Evaluation of soil processing conditions on mineralizable C and N across a textural gradient

USDA-ARS?s Scientific Manuscript database

Soil biological activity is an important component of a well-functioning soil. Methodologies for estimating this process in soil vary due to a variety of theoretical, functional, and expediency considerations. We tested the effects of soil processing (sieve size), water delivery method (from top a...

Common and distinct neural substrates for the perception of speech rhythm and intonation.

PubMed

Zhang, Linjun; Shu, Hua; Zhou, Fengying; Wang, Xiaoyi; Li, Ping

2010-07-01

The present study examines the neural substrates for the perception of speech rhythm and intonation. Subjects listened passively to synthesized speech stimuli that contained no semantic and phonological information, in three conditions: (1) continuous speech stimuli with fixed syllable duration and fundamental frequency in the standard condition, (2) stimuli with varying vocalic durations of syllables in the speech rhythm condition, and (3) stimuli with varying fundamental frequency in the intonation condition. Compared to the standard condition, speech rhythm activated the right middle superior temporal gyrus (mSTG), whereas intonation activated the bilateral superior temporal gyrus and sulcus (STG/STS) and the right posterior STS. Conjunction analysis further revealed that rhythm and intonation activated a common area in the right mSTG but compared to speech rhythm, intonation elicited additional activations in the right anterior STS. Findings from the current study reveal that the right mSTG plays an important role in prosodic processing. Implications of our findings are discussed with respect to neurocognitive theories of auditory processing. (c) 2009 Wiley-Liss, Inc.

Electrophysiological spatiotemporal dynamics during implicit visual threat processing.

PubMed

DeLaRosa, Bambi L; Spence, Jeffrey S; Shakal, Scott K M; Motes, Michael A; Calley, Clifford S; Calley, Virginia I; Hart, John; Kraut, Michael A

2014-11-01

Numerous studies have found evidence for corticolimbic theta band electroencephalographic (EEG) oscillations in the neural processing of visual stimuli perceived as threatening. However, varying temporal and topographical patterns have emerged, possibly due to varying arousal levels of the stimuli. In addition, recent studies suggest neural oscillations in delta, theta, alpha, and beta-band frequencies play a functional role in information processing in the brain. This study implemented a data-driven PCA based analysis investigating the spatiotemporal dynamics of electroencephalographic delta, theta, alpha, and beta-band frequencies during an implicit visual threat processing task. While controlling for the arousal dimension (the intensity of emotional activation), we found several spatial and temporal differences for threatening compared to nonthreatening visual images. We detected an early posterior increase in theta power followed by a later frontal increase in theta power, greatest for the threatening condition. There was also a consistent left lateralized beta desynchronization for the threatening condition. Our results provide support for a dynamic corticolimbic network, with theta and beta band activity indexing processes pivotal in visual threat processing. Published by Elsevier Inc.

Differences in nutrient uptake capacity of the benthic filamentous algae Cladophora sp., Klebsormidium sp. and Pseudanabaena sp. under varying N/P conditions.

PubMed

Liu, Junzhuo; Vyverman, Wim

2015-03-01

The N/P ratio of wastewater can vary greatly and directly affect algal growth and nutrient removal process. Three benthic filamentous algae species Cladophora sp., Klebsormidium sp. and Pseudanabaena sp. were isolated from a periphyton bioreactor and cultured under laboratory conditions on varying N/P ratios to determine their ability to remove nitrate and phosphorus. The N/P ratio significantly influenced the algal growth and phosphorus uptake process. Appropriate N/P ratios for nitrogen and phosphorus removal were 5-15, 7-10 and 7-20 for Cladophora sp., Klebsormidium sp. and Pseudanabaena sp., respectively. Within these respective ranges, Cladophora sp. had the highest biomass production, while Pseudanabaena sp. had the highest nitrogen and phosphorus contents. This study indicated that Cladophora sp. had a high capacity of removing phosphorus from wastewaters of low N/P ratio, and Pseudanabaena sp. was highly suitable for removing nitrogen from wastewaters with high N/P ratio. Copyright © 2014 Elsevier Ltd. All rights reserved.

Jet fuels from synthetic crudes

NASA Technical Reports Server (NTRS)

Antoine, A. C.; Gallagher, J. P.

1977-01-01

An investigation was conducted to determine the technical problems in the conversion of a significant portion of a barrel of either a shale oil or a coal synthetic crude oil into a suitable aviation turbine fuel. Three syncrudes were used, one from shale and two from coal, chosen as representative of typical crudes from future commercial production. The material was used to produce jet fuels of varying specifications by distillation, hydrotreating, and hydrocracking. Attention is given to process requirements, hydrotreating process conditions, the methods used to analyze the final products, the conditions for shale oil processing, and the coal liquid processing conditions. The results of the investigation show that jet fuels of defined specifications can be made from oil shale and coal syncrudes using readily available commercial processes.

ICUMSA general subject 7 cane sugar processing report

USDA-ARS?s Scientific Manuscript database

In recent years there has been a world-wide increase in starch concentrations mostly because of one or a combination of the following: (i) increased mechanical processing of green sugarcane; (ii) varying environmental conditions; and (iii) newer sugarcane varieties with higher starch content. Many i...

Numerical Modeling of High-Temperature Corrosion Processes

NASA Technical Reports Server (NTRS)

Nesbitt, James A.

1995-01-01

Numerical modeling of the diffusional transport associated with high-temperature corrosion processes is reviewed. These corrosion processes include external scale formation and internal subscale formation during oxidation, coating degradation by oxidation and substrate interdiffusion, carburization, sulfidation and nitridation. The studies that are reviewed cover such complexities as concentration-dependent diffusivities, cross-term effects in ternary alloys, and internal precipitation where several compounds of the same element form (e.g., carbides of Cr) or several compounds exist simultaneously (e.g., carbides containing varying amounts of Ni, Cr, Fe or Mo). In addition, the studies involve a variety of boundary conditions that vary with time and temperature. Finite-difference (F-D) techniques have been applied almost exclusively to model either the solute or corrodant transport in each of these studies. Hence, the paper first reviews the use of F-D techniques to develop solutions to the diffusion equations with various boundary conditions appropriate to high-temperature corrosion processes. The bulk of the paper then reviews various F-D modeling studies of diffusional transport associated with high-temperature corrosion.

Effects of and preference for pay for performance: an analogue analysis.

PubMed

Long, Robert D; Wilder, David A; Betz, Alison; Dutta, Ami

2012-01-01

We examined the effects of 2 payment systems on the rate of check processing and time spent on task by participants in a simulated work setting. Three participants experienced individual pay-for-performance (PFP) without base pay and pay-for-time (PFT) conditions. In the last phase, we asked participants to choose which system they preferred. For all participants, the PFP condition produced higher rates of check processing and more time spent on task than did the PFT condition, but choice of payment system varied both within and across participants.

Processing deficits for familiar and novel faces in patients with left posterior fusiform lesions.

PubMed

Roberts, Daniel J; Lambon Ralph, Matthew A; Kim, Esther; Tainturier, Marie-Josephe; Beeson, Pelagie M; Rapcsak, Steven Z; Woollams, Anna M

2015-11-01

Pure alexia (PA) arises from damage to the left posterior fusiform gyrus (pFG) and the striking reading disorder that defines this condition has meant that such patients are often cited as evidence for the specialisation of this region to processing of written words. There is, however, an alternative view that suggests this region is devoted to processing of high acuity foveal input, which is particularly salient for complex visual stimuli like letter strings. Previous reports have highlighted disrupted processing of non-linguistic visual stimuli after damage to the left pFG, both for familiar and unfamiliar objects and also for novel faces. This study explored the nature of face processing deficits in patients with left pFG damage. Identification of famous faces was found to be compromised in both expressive and receptive tasks. Discrimination of novel faces was also impaired, particularly for those that varied in terms of second-order spacing information, and this deficit was most apparent for the patients with the more severe reading deficits. Interestingly, discrimination of faces that varied in terms of feature identity was considerably better in these patients and it was performance in this condition that was related to the size of the length effects shown in reading. This finding complements functional imaging studies showing left pFG activation for faces varying only in spacing and frontal activation for faces varying only on features. These results suggest that the sequential part-based processing strategy that promotes the length effect in the reading of these patients also allows them to discriminate between faces on the basis of feature identity, but processing of second-order configural information is most compromised due to their left pFG lesion. This study supports a view in which the left pFG is specialised for processing of high acuity foveal visual information that supports processing of both words and faces. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Processing deficits for familiar and novel faces in patients with left posterior fusiform lesions

PubMed Central

Roberts, Daniel J.; Lambon Ralph, Matthew A.; Kim, Esther; Tainturier, Marie-Josephe; Beeson, Pelagie M.; Rapcsak, Steven Z.; Woollams, Anna M.

2015-01-01

Pure alexia (PA) arises from damage to the left posterior fusiform gyrus (pFG) and the striking reading disorder that defines this condition has meant that such patients are often cited as evidence for the specialisation of this region to processing of written words. There is, however, an alternative view that suggests this region is devoted to processing of high acuity foveal input, which is particularly salient for complex visual stimuli like letter strings. Previous reports have highlighted disrupted processing of non-linguistic visual stimuli after damage to the left pFG, both for familiar and unfamiliar objects and also for novel faces. This study explored the nature of face processing deficits in patients with left pFG damage. Identification of famous faces was found to be compromised in both expressive and receptive tasks. Discrimination of novel faces was also impaired, particularly for those that varied in terms of second-order spacing information, and this deficit was most apparent for the patients with the more severe reading deficits. Interestingly, discrimination of faces that varied in terms of feature identity was considerably better in these patients and it was performance in this condition that was related to the size of the length effects shown in reading. This finding complements functional imaging studies showing left pFG activation for faces varying only in spacing and frontal activation for faces varying only on features. These results suggest that the sequential part-based processing strategy that promotes the length effect in the reading of these patients also allows them to discriminate between faces on the basis of feature identity, but processing of second-order configural information is most compromised due to their left pFG lesion. This study supports a view in which the left pFG is specialised for processing of high acuity foveal visual information that supports processing of both words and faces. PMID:25837867

How High Pressure Unifies Solvation Processes in Liquid Chromatography.

PubMed

Bocian, Szymon; Škrinjar, Tea; Bolanca, Tomislav; Buszewski, Bogusław

2017-11-01

A series of core-shell-based stationary phases of varying surface chemistry were subjected to solvent adsorption investigation under ultra-HPLC conditions. Acetonitrile and water excess isotherms were measured using a minor disturbance method. It was observed that adsorption of organic solvent is unified under high pressure. Preferential solvation due to specific interactions between the stationary phases and solvent molecules was limited. The obtained results showed that the solvation process is almost independent of surface chemistry, in contrast to HPLC conditions in which specific interactions differentiate solvation processes.

Effect of storage conditions on the calorific value of municipal solid waste.

PubMed

Nzioka, Antony Mutua; Hwang, Hyeon-Uk; Kim, Myung-Gyun; Yan, Cao Zheng; Lee, Chang-Soo; Kim, Young-Ju

2017-08-01

Storage conditions are considered to be an important factor as far as waste material characteristics are concerned. This experimental investigation was conducted using municipal solid waste (MSW) with a high moisture content and varying composition of organic waste. The objective of this study was to understand the effect of storage conditions and temperature on the moisture content and calorific value of the waste. Samples were subjected to two different storage conditions and investigated at specified temperatures. The composition of sample materials investigated was varied for each storage condition and temperature respectively. Gross calorific value was determined experimentally while net calorific value was calculated using empirical formulas proposed by other researchers. Results showed minimal changes in moisture content as well as in gross and net calorific values when the samples were subjected to sealed storage conditions. Moisture content reduced due to the ventilation process and the rate of moisture removal increased with a rise in storage temperature. As expected, rate of moisture removal had a positive effect on gross and net calorific values. Net calorific values also increased at varying rates with a simultaneous decrease in moisture content. Experimental investigation showed the effectiveness of ventilation in improving the combustion characteristics of the waste.

Detection of Subsurface Defects in Levees in Correlation to Weather Conditions Utilizing Ground Penetrating Radar

NASA Astrophysics Data System (ADS)

Martinez, I. A.; Eisenmann, D.

2012-12-01

Ground Penetrating Radar (GPR) has been used for many years in successful subsurface detection of conductive and non-conductive objects in all types of material including different soils and concrete. Typical defect detection is based on subjective examination of processed scans using data collection and analysis software to acquire and analyze the data, often requiring a developed expertise or an awareness of how a GPR works while collecting data. Processing programs, such as GSSI's RADAN analysis software are then used to validate the collected information. Iowa State University's Center for Nondestructive Evaluation (CNDE) has built a test site, resembling a typical levee used near rivers, which contains known sub-surface targets of varying size, depth, and conductivity. Scientist at CNDE have developed software with the enhanced capabilities, to decipher a hyperbola's magnitude and amplitude for GPR signal processing. With this enhanced capability, the signal processing and defect detection capabilities for GPR have the potential to be greatly enhanced. This study will examine the effects of test parameters, antenna frequency (400MHz), data manipulation methods (which include data filters and restricting the range of depth in which the chosen antenna's signal can reach), and real-world conditions using this test site (such as varying weather conditions) , with the goal of improving GPR tests sensitivity for differing soil conditions.

INFLUENCE OF PH AND REDOX CONDITIONS ON COPPER LEACHING

EPA Science Inventory

Leaching behavior of metals from a mineral processing waste at varying pH and redox conditions was studies. Effect of combinations of pH and Eh on leaching of copper is described. Leaching of copper was found to be dependent on both pH and Eh. Higher concentrations of Cu were ...

A recipe for primordial soup

NASA Technical Reports Server (NTRS)

Kolb, E.

2001-01-01

If the universe emerged from a state of high temperature and high density, we can study the origin of the universe by recreating those conditions in the laboratory. While we can not reproduce the Big Bang, we can recreate its conditions and study the physical processes responsible for producing the rich and varied universe we observe today.

Friction and lubrication modelling in sheet metal forming: Influence of lubrication amount, tool roughness and sheet coating on product quality

NASA Astrophysics Data System (ADS)

Hol, J.; Wiebenga, J. H.; Carleer, B.

2017-09-01

In the stamping of automotive parts, friction and lubrication play a key role in achieving high quality products. In the development process of new automotive parts, it is therefore crucial to accurately account for these effects in sheet metal forming simulations. This paper presents a selection of results considering friction and lubrication modelling in sheet metal forming simulations of a front fender product. For varying lubrication conditions, the front fender can either show wrinkling or fractures. The front fender is modelled using different lubrication amounts, tool roughness’s and sheet coatings to show the strong influence of friction on both part quality and the overall production stability. For this purpose, the TriboForm software is used in combination with the AutoForm software. The results demonstrate that the TriboForm software enables the simulation of friction behaviour for varying lubrication conditions, i.e. resulting in a generally applicable approach for friction characterization under industrial sheet metal forming process conditions.

Dynamic predictive model for the growth of Salmonella spp. in liquid whole egg.

PubMed

Singh, Aikansh; Korasapati, Nageswara R; Juneja, Vijay K; Subbiah, Jeyamkondan; Froning, Glenn; Thippareddi, Harshavardhan

2011-04-01

A dynamic model for the growth of Salmonella spp. in liquid whole egg (LWE) (approximately pH 7.8) under continuously varying temperature was developed. The model was validated using 2 (5 to 15 °C; 600 h and 10 to 40 °C; 52 h) sinusoidal, continuously varying temperature profiles. LWE adjusted to pH 7.8 was inoculated with approximately 2.5-3.0 log CFU/mL of Salmonella spp., and the growth data at several isothermal conditions (5, 7, 10, 15, 20, 25, 30, 35, 37, 39, 41, 43, 45, and 47 °C) was collected. A primary model (Baranyi model) was fitted for each temperature growth data and corresponding maximum growth rates were estimated. Pseudo-R2 values were greater than 0.97 for primary models. Modified Ratkowsky model was used to fit the secondary model. The pseudo-R2 and root mean square error were 0.99 and 0.06 log CFU/mL, respectively, for the secondary model. A dynamic model for the prediction of Salmonella spp. growth under varying temperature conditions was developed using 4th-order Runge-Kutta method. The developed dynamic model was validated for 2 sinusoidal temperature profiles, 5 to 15 °C (for 600 h) and 10 to 40 °C (for 52 h) with corresponding root mean squared error values of 0.28 and 0.23 log CFU/mL, respectively, between predicted and observed Salmonella spp. populations. The developed dynamic model can be used to predict the growth of Salmonella spp. in LWE under varying temperature conditions.   Liquid egg and egg products are widely used in food processing and in restaurant operations. These products can be contaminated with Salmonella spp. during breaking and other unit operations during processing. The raw, liquid egg products are stored under refrigeration prior to pasteurization. However, process deviations can occur such as refrigeration failure, leading to temperature fluctuations above the required temperatures as specified in the critical limits within hazard analysis and critical control point plans for the operations. The processors are required to evaluate the potential growth of Salmonella spp. in such products before the product can be used, or further processed. Dynamic predictive models are excellent tools for regulators as well as the processing plant personnel to evaluate the microbiological safety of the product under such conditions.

Geologic Conditions Required for the Fluvial Erosion of Titan’s Craters

NASA Astrophysics Data System (ADS)

Kinser, Rebeca; Neish, Catherine; Howard, Alan; Schenk, Paul; Bray, Veronica

2015-11-01

In comparison to other icy satellites, Titan has a small number of impact craters on its surface. This suggests that it has a young surface and/or erosional processes that remove craters from its surface. The set of geological conditions on Titan that would allow craters to become unrecognizable by orbiting spacecraft such as Cassini is unclear. Initial results suggest that not all geologic conditions would allow for complete degradation of impact craters on Titan. Using a landscape evolution model, we explored a larger parameter space to determine the conditions under which a representative 40 km crater on Titan would be eroded. We focused on varying the values of parameters such as bedrock and regolith erodibility, sediment grain size, the weathering rate of the regolith, and whether or not the regolith was saturated with liquid hydrocarbons. We found that only after changing the saturation state of the regolith mid-way through the simulation was it possible to completely erode the crater. Since there are few craters on Titan, this suggests that during Titan’s geological history there may have been varying quantities of liquid on its surface. Titan is known to have a dense atmosphere, not unlike that of the Earth, that could allow for surface liquids to vary under a changing climate. The erosion rate could then also vary as a direct result of changing climatic conditions.

An investigation of squeeze-cast alloy 718

NASA Technical Reports Server (NTRS)

Gamwell, W. R.

1993-01-01

Alloy 718 billets produced by the squeeze-cast process have been evaluated for use as potential replacements for propulsion engine components which are normally produced from forgings. Alloy 718 billets were produced using various processing conditions. Structural characterizations were performed on 'as-cast' billets. As-cast billets were then homogenized and solution treated and aged according to conventional heat-treatment practices for this alloy. Mechanical property evaluations were performed on heat-treated billets. As-cast macrostructures and microstructures varied with squeeze-cast processing parameters. Mechanical properties varied with squeeze-cast processing parameters and heat treatments. One billet exhibited a defect free, refined microstructure, with mechanical properties approaching those of wrought alloy 718 bar, confirming the feasibility of squeeze-casting alloy 718. However, further process optimization is required, and further structural and mechanical property improvements are expected with process optimization.

Biological Potential in Serpentinizing Systems

NASA Technical Reports Server (NTRS)

Hoehler, Tori M.

2016-01-01

Generation of the microbial substrate hydrogen during serpentinization, the aqueous alteration of ultramafic rocks, has focused interest on the potential of serpentinizing systems to support biological communities or even the origin of life. However the process also generates considerable alkalinity, a challenge to life, and both pH and hydrogen concentrations vary widely across natural systems as a result of different host rock and fluid composition and differing physical and hydrogeologic conditions. Biological potential is expected to vary in concert. We examined the impact of such variability on the bioenergetics of an example metabolism, methanogenesis, using a cell-scale reactive transport model to compare rates of metabolic energy generation as a function of physicochemical environment. Potential rates vary over more than 5 orders of magnitude, including bioenergetically non-viable conditions, across the range of naturally occurring conditions. In parallel, we assayed rates of hydrogen metabolism in wells associated with the actively serpentinizing Coast Range Ophiolite, which includes conditions more alkaline and considerably less reducing than is typical of serpentinizing systems. Hydrogen metabolism is observed at pH approaching 12 but, consistent with the model predictions, biological methanogenesis is not observed.

Reading Rate, Readability and Variations in Task-Induced Processing.

ERIC Educational Resources Information Center

Coke, Esther U.

This study examined the adaptability of reading rate to passage difficulty under different conditions of task-induced processing. Sixteen experimental passages varying in subject matter and ranging from 85 to 171 words were selected from a set of 32 texts rated for comprehensibility. The eight easiest and eight hardest texts were selected. Another…

The role of surface charge in the desolvation process of gelatin: implications in nanoparticle synthesis and modulation of drug release

PubMed Central

Ahsan, Saad M; Rao, Chintalagiri Mohan

2017-01-01

The process of moving hydrophobic amino acids into the core of a protein by desolvation is important in protein folding. However, a rapid and forced desolvation can lead to precipitation of proteins. Desolvation of proteins under controlled conditions generates nanoparticles – homogeneous aggregates with a narrow size distribution. The protein nanoparticles, under physiological conditions, undergo surface erosion due to the action of proteases, releasing the entrapped drug/gene. The packing density of protein nanoparticles significantly influences the release kinetics. We have investigated the desolvation process of gelatin, exploring the role of pH and desolvating agent in nanoparticle synthesis. Our results show that the desolvation process, initiated by the addition of acetone, follows distinct pathways for gelatin incubated at different pH values and results in the generation of nanoparticles with varying matrix densities. The nanoparticles synthesized with varying matrix densities show variations in drug loading and protease-dependent extra- and intracellular drug release. These results will be useful in fine-tuning the synthesis of nanoparticles with desirable drug release profiles. PMID:28182126

Crack propagation monitoring in a full-scale aircraft fatigue test based on guided wave-Gaussian mixture model

NASA Astrophysics Data System (ADS)

Qiu, Lei; Yuan, Shenfang; Bao, Qiao; Mei, Hanfei; Ren, Yuanqiang

2016-05-01

For aerospace application of structural health monitoring (SHM) technology, the problem of reliable damage monitoring under time-varying conditions must be addressed and the SHM technology has to be fully validated on real aircraft structures under realistic load conditions on ground before it can reach the status of flight test. In this paper, the guided wave (GW) based SHM method is applied to a full-scale aircraft fatigue test which is one of the most similar test status to the flight test. To deal with the time-varying problem, a GW-Gaussian mixture model (GW-GMM) is proposed. The probability characteristic of GW features, which is introduced by time-varying conditions is modeled by GW-GMM. The weak cumulative variation trend of the crack propagation, which is mixed in time-varying influence can be tracked by the GW-GMM migration during on-line damage monitoring process. A best match based Kullback-Leibler divergence is proposed to measure the GW-GMM migration degree to reveal the crack propagation. The method is validated in the full-scale aircraft fatigue test. The validation results indicate that the reliable crack propagation monitoring of the left landing gear spar and the right wing panel under realistic load conditions are achieved.

Electrophysiological CNS-processes related to associative learning in humans.

PubMed

Christoffersen, Gert R J; Schachtman, Todd R

2016-01-01

The neurophysiology of human associative memory has been studied with electroencephalographic techniques since the 1930s. This research has revealed that different types of electrophysiological processes in the human brain can be modified by conditioning: sensory evoked potentials, sensory induced gamma-band activity, periods of frequency-specific waves (alpha and beta waves, the sensorimotor rhythm and the mu-rhythm) and slow cortical potentials. Conditioning of these processes has been studied in experiments that either use operant conditioning or repeated contingent pairings of conditioned and unconditioned stimuli (classical conditioning). In operant conditioning, the appearance of a specific brain process is paired with an external stimulus (neurofeedback) and the feedback enables subjects to obtain varying degrees of control of the CNS-process. Such acquired self-regulation of brain activity has found practical uses for instance in the amelioration of epileptic seizures, Autism Spectrum Disorders (ASD) and Attention Deficit Hyperactivity Disorder (ADHD). It has also provided communicative means of assistance for tetraplegic patients through the use of brain computer interfaces. Both extra and intracortically recorded signals have been coupled with contingent external feedback. It is the aim for this review to summarize essential results on all types of electromagnetic brain processes that have been modified by classical or operant conditioning. The results are organized according to type of conditioned EEG-process, type of conditioning, and sensory modalities of the conditioning stimuli. Copyright © 2015 Elsevier B.V. All rights reserved.

Fine-tuning of process conditions to improve product uniformity of polystyrene particles used for wind tunnel velocimetry

NASA Technical Reports Server (NTRS)

Ray, Asit K.

1990-01-01

Monodisperse polymer particles (having uniform diameter) were used for the last two decades in physical, biological, and chemical sciences. In NASA Langley Research Center monodisperse polystyrene particles are used in wind tunnel laser velocimeters. These polystyrene (PS) particles in latex form were formulated at the Engineering Laboratory of FENGD using emulsion-free emulsion polymerization. Monodisperse PS latices particles having different particle diameters were formulated and useful experimental data involving effects of process conditions on particle size were accumulated. However, similar process conditions and chemical recipes for polymerization of styrene monomer have often yielded monodisperse particles having varying diameters. The purpose was to improve the PS latex product uniformity by fine-tuning the process parameters based on the knowledge of suspension and emulsion polymerization.

Oil-in-water emulsification using confined impinging jets.

PubMed

Siddiqui, Shad W; Norton, Ian T

2012-07-01

A confined impinging jet mixing device has been used to investigate the continuous sunflower oil/water emulsification process under turbulent flow conditions with oil contents between 5% (v/v) and 10% (v/v). Various emulsifiers (Tween20, Span80, Whey Protein, Lecithin and Sodium Dodecylsulphate) varying in molecular weights have been studied. Mean droplet sizes varied with the emulsifiers used and smallest droplets were obtained under fully turbulent flow regime, i.e. at the highest jet flow rate and highest jet Reynolds Number conditions. Sodium Dodecylsulfate (SDS) produced droplets in the range of 3.8 μm while 6 μm droplets were obtained with Whey Protein. Similar droplet sizes were obtained under fully turbulent flow conditions (610 mL/min; Reynolds Number=13,000) for oil content varying between 5% (v/v) and 10% (v/v). To investigate the smallest droplet size possible in the device, the emulsion was passed through the geometry multiple times. Multi-pass emulsification resulted in reduction in droplet size indicating that longer residence in the flow field under high shear condition allowed for breakage of droplets as well as the time for the emulsifier to stabilize the newly formed droplets, decreasing the impact of coalescence. This was confirmed by timescale analysis of the involved process steps for the droplet data obtained via experiments. Dependence of mean droplet size on the o/w interfacial tension and peak energy dissipation was also investigated. Copyright © 2012 Elsevier Inc. All rights reserved.

A digital computer simulation and study of a direct-energy-transfer power-conditioning system

NASA Technical Reports Server (NTRS)

Burns, W. W., III; Owen, H. A., Jr.; Wilson, T. G.; Rodriguez, G. E.; Paulkovich, J.

1974-01-01

A digital computer simulation technique, which can be used to study such composite power-conditioning systems, was applied to a spacecraft direct-energy-transfer power-processing system. The results obtained duplicate actual system performance with considerable accuracy. The validity of the approach and its usefulness in studying various aspects of system performance such as steady-state characteristics and transient responses to severely varying operating conditions are demonstrated experimentally.

Time-varying nonstationary multivariate risk analysis using a dynamic Bayesian copula

NASA Astrophysics Data System (ADS)

Sarhadi, Ali; Burn, Donald H.; Concepción Ausín, María.; Wiper, Michael P.

2016-03-01

A time-varying risk analysis is proposed for an adaptive design framework in nonstationary conditions arising from climate change. A Bayesian, dynamic conditional copula is developed for modeling the time-varying dependence structure between mixed continuous and discrete multiattributes of multidimensional hydrometeorological phenomena. Joint Bayesian inference is carried out to fit the marginals and copula in an illustrative example using an adaptive, Gibbs Markov Chain Monte Carlo (MCMC) sampler. Posterior mean estimates and credible intervals are provided for the model parameters and the Deviance Information Criterion (DIC) is used to select the model that best captures different forms of nonstationarity over time. This study also introduces a fully Bayesian, time-varying joint return period for multivariate time-dependent risk analysis in nonstationary environments. The results demonstrate that the nature and the risk of extreme-climate multidimensional processes are changed over time under the impact of climate change, and accordingly the long-term decision making strategies should be updated based on the anomalies of the nonstationary environment.

Quality Assurance Processes in Finnish Universities: Direct and Indirect Outcomes and Organisational Conditions

ERIC Educational Resources Information Center

Haapakorpi, Arja

2011-01-01

In Finland, quality assurance related to the Bologna process has been adapted to existing systems of higher education at the national level and a form of implementation is also recognised at the level of the higher education institution. In universities, varied outcomes of quality assurance are based on interaction of organisational structures,…

The effect of encoding manipulation on word-stem cued recall: an event-related potential study.

PubMed

Fay, Séverine; Isingrini, Michel; Ragot, Richard; Pouthas, Viviane

2005-08-01

The purpose of the present study was to find out whether the neural correlates of explicit retrieval from episodic memory would vary according to conditions at encoding when the words were presented in separate study/test blocks. Event-related potentials (ERPs) were recorded while participants performed a word-stem cued-recall task. Deeply (semantically) studied words were associated with higher levels of recall and faster response times than shallowly (lexically) studied words. Robust ERP old/new effects were observed for each encoding condition. They varied in magnitude, being largest in the semantic condition. As expected, scalp distributions also differed: for deeply studied words, the old/new effect resembled that found in previous ERP studies of word-stem cued-recall tasks (parietal and right frontal effects, between 400-800 and 800-1100 ms post-stimulus), whereas for shallowly studied words, the parietal old/new effect was absent in the latter latency window. These results can be interpreted as reflecting access to different kinds of memory representation depending on the nature of the processing engaged during encoding. Furthermore, differences in the ERPs elicited by new items indicate that subjects adopted different processing strategies in the test blocks following each encoding condition.

Analysing the Friction Stir Welded Joints of AA2219 Al-Cu Alloy in Different Heat-Treated-State

NASA Astrophysics Data System (ADS)

Venkateswarlu, D.; Cheepu, Muralimohan; Kranthi kumar, B.; Mahapatra, M. M.

2018-03-01

Aluminium alloy AA2219 is widely used in light weight structural applications where the good corrosion resistance and specific weight required. The fabrication of this alloy using friction stir welding process is gaining interest towards finding the characteristics of the weld metal properties, since this process involved in the welded materials does not melt and recast. In the present investigation, friction stir welding process was used for different heat treated conditions of 2219-T87 and 2219-T62 aluminium alloys to find the influence of base metal on characteristics of the joints. The experimental output results exhibited that, mechanical properties, weld metal characteristics and joint failure locations are significantly affected by the different heat treatment conditions of the substrate. The joints tensile and yield strength of the 2219-T87 welds was higher than the 2219-T62 welds. Hardness distribution in the stir zone was significantly varied between two different heat treaded material conditions. The microstructural features of the 2219-T62 welds reveal the coarse grains formation in the thermo-mechanically affected zone and heat affected zone. The joint efficiency of the 2219- T82 welds is 59.87%, while that of 2219-T62 welds is 39.10%. In addition, the elongation of the joint also varied and the joints failure location characteristics are different for two different types heat treated condition joints.

The metaphysics of evolution.

PubMed

Dupré, John

2017-10-06

This paper briefly describes process metaphysics, and argues that it is better suited for describing life than the more standard thing, or substance, metaphysics. It then explores the implications of process metaphysics for conceptualizing evolution. After explaining what it is for an organism to be a process, the paper takes up the Hull/Ghiselin thesis of species as individuals and explores the conditions under which a species or lineage could constitute an individual process. It is argued that only sexual species satisfy these conditions, and that within sexual species the degree of organization varies. This, in turn, has important implications for species' evolvability. One important moral is that evolution will work differently in different biological domains.

The metaphysics of evolution

PubMed Central

2017-01-01

This paper briefly describes process metaphysics, and argues that it is better suited for describing life than the more standard thing, or substance, metaphysics. It then explores the implications of process metaphysics for conceptualizing evolution. After explaining what it is for an organism to be a process, the paper takes up the Hull/Ghiselin thesis of species as individuals and explores the conditions under which a species or lineage could constitute an individual process. It is argued that only sexual species satisfy these conditions, and that within sexual species the degree of organization varies. This, in turn, has important implications for species' evolvability. One important moral is that evolution will work differently in different biological domains. PMID:28839921

The effect of bedload transport rates on bedform and planform morphological development in a laboratory meandering stream under varying flow conditions

NASA Astrophysics Data System (ADS)

Sullivan, C.; Good, R. G. R.; Binns, A. D.

2017-12-01

Sediment transport processes in streams provides valuable insight into the temporal evolution of planform and bedform geometry. The majority of previous experimental research in the literature has focused on bedload transport and corresponding bedform development in rectangular, confined channels, which does not consider planform adjustment processes in streams. In contrast, research conducted with laboratory streams having movable banks can investigate planform development in addition to bedform development, which is more representative of natural streams. The goal of this research is to explore the relationship between bedload transport rates and the morphological adjustments in meandering streams. To accomplish this, a series of experimental runs were conducted in a 5.6 m by 1.9 m river basin flume at the University of Guelph to analyze the bedload impacts on bed formations and planform adjustments in response to varying flow conditions. In total, three experimental runs were conducted: two runs using steady state conditions and one run using unsteady flow conditions in the form of a symmetrical hydrograph implementing quasi steady state flow. The runs were performed in a series of time-steps in order to monitor the evolution of the stream morphology and the bedload transport rates. Structure from motion (SfM) was utilized to capture the channel morphology after each time-step, and Agisoft PhotoScan software was used to produce digital elevation models to analyze the morphological evolution of the channel with time. Bedload transport rates were quantified using a sediment catch at the end of the flume. Although total flow volumes were similar for each run, the morphological evolution and bedload transport rates in each run varied. The observed bedload transport rates from the flume are compared with existing bedload transport formulas to assess their accuracy with respect to sediment transport in unconfined meandering channels. The measured sediment transport rates varied from the existing equations, which can be attributed to the sediment characteristics, planform morphology and bed formations. The results from this research provide greater knowledge of morphological processes in natural meandering streams to improve the capabilities of computational modelling and river engineering practice.

Drying and heat decomposition of biomass during the production of biochar

NASA Astrophysics Data System (ADS)

Lyubov, V. K.; Popova, E. I.

2017-11-01

The process of wood torrefaction provides an opportunity to combine properties of biofuel and steam coal. Different degrees of biofuel heat treating leads to varied outcomes and varied biochar heating value. Therefore, the torrefaction process requires optimal operation that ensures the highest heating value of biochar with the lowest energy loss. In this paper we present the experimental results of drying cycle and thermal decomposition of particles of spruce stem wood and hydrolytic lignin in argon under various temperature conditions and basic material humidity as well as changes in the morphological structure of the biomass and its grain size composition during the torrefaction.

The Impact of Attention on Judgments of Frequency and Duration

PubMed Central

Winkler, Isabell; Glauer, Madlen; Betsch, Tilmann; Sedlmeier, Peter

2015-01-01

Previous studies that examined human judgments of frequency and duration found an asymmetrical relationship: While frequency judgments were quite accurate and independent of stimulus duration, duration judgments were highly dependent upon stimulus frequency. A potential explanation for these findings is that the asymmetry is moderated by the amount of attention directed to the stimuli. In the current experiment, participants' attention was manipulated in two ways: (a) intrinsically, by varying the type and arousal potential of the stimuli (names, low-arousal and high-arousal pictures), and (b) extrinsically, by varying the physical effort participants expended during the stimulus presentation (by lifting a dumbbell vs. relaxing the arm). Participants processed stimuli with varying presentation frequencies and durations and were subsequently asked to estimate the frequency and duration of each stimulus. Sensitivity to duration increased for pictures in general, especially when processed under physical effort. A large effect of stimulus frequency on duration judgments was obtained for all experimental conditions, but a similar large effect of presentation duration on frequency judgments emerged only in the conditions that could be expected to draw high amounts of attention to the stimuli: when pictures were judged under high physical effort. Almost no difference in the mutual impact of frequency and duration was obtained for low-arousal or high-arousal pictures. The mechanisms underlying the simultaneous processing of frequency and duration are discussed with respect to existing models derived from animal research. Options for the extension of such models to human processing of frequency and duration are suggested. PMID:26000712

The impact of attention on judgments of frequency and duration.

PubMed

Winkler, Isabell; Glauer, Madlen; Betsch, Tilmann; Sedlmeier, Peter

2015-01-01

Previous studies that examined human judgments of frequency and duration found an asymmetrical relationship: While frequency judgments were quite accurate and independent of stimulus duration, duration judgments were highly dependent upon stimulus frequency. A potential explanation for these findings is that the asymmetry is moderated by the amount of attention directed to the stimuli. In the current experiment, participants' attention was manipulated in two ways: (a) intrinsically, by varying the type and arousal potential of the stimuli (names, low-arousal and high-arousal pictures), and (b) extrinsically, by varying the physical effort participants expended during the stimulus presentation (by lifting a dumbbell vs. relaxing the arm). Participants processed stimuli with varying presentation frequencies and durations and were subsequently asked to estimate the frequency and duration of each stimulus. Sensitivity to duration increased for pictures in general, especially when processed under physical effort. A large effect of stimulus frequency on duration judgments was obtained for all experimental conditions, but a similar large effect of presentation duration on frequency judgments emerged only in the conditions that could be expected to draw high amounts of attention to the stimuli: when pictures were judged under high physical effort. Almost no difference in the mutual impact of frequency and duration was obtained for low-arousal or high-arousal pictures. The mechanisms underlying the simultaneous processing of frequency and duration are discussed with respect to existing models derived from animal research. Options for the extension of such models to human processing of frequency and duration are suggested.

Production of Methane and Water from Crew Plastic Waste

NASA Technical Reports Server (NTRS)

Captain, Janine; Santiago, Eddie; Parrish, Clyde; Strayer, Richard F.; Garland, Jay L.

2008-01-01

Recycling is a technology that will be key to creating a self sustaining lunar outpost. The plastics used for food packaging provide a source of material that could be recycled to produce water and methane. The recycling of these plastics will require some additional resources that will affect the initial estimate of starting materials that will have to be transported from earth, mainly oxygen, energy and mass. These requirements will vary depending on the recycling conditions. The degredation products of these plastics will vary under different atmospheric conditions. An estimate of the the production rate of methane and water using typical ISRU processes along with the plastic recycling will be presented.

Bearing fault diagnosis under unknown time-varying rotational speed conditions via multiple time-frequency curve extraction

NASA Astrophysics Data System (ADS)

Huang, Huan; Baddour, Natalie; Liang, Ming

2018-02-01

Under normal operating conditions, bearings often run under time-varying rotational speed conditions. Under such circumstances, the bearing vibrational signal is non-stationary, which renders ineffective the techniques used for bearing fault diagnosis under constant running conditions. One of the conventional methods of bearing fault diagnosis under time-varying speed conditions is resampling the non-stationary signal to a stationary signal via order tracking with the measured variable speed. With the resampled signal, the methods available for constant condition cases are thus applicable. However, the accuracy of the order tracking is often inadequate and the time-varying speed is sometimes not measurable. Thus, resampling-free methods are of interest for bearing fault diagnosis under time-varying rotational speed for use without tachometers. With the development of time-frequency analysis, the time-varying fault character manifests as curves in the time-frequency domain. By extracting the Instantaneous Fault Characteristic Frequency (IFCF) from the Time-Frequency Representation (TFR) and converting the IFCF, its harmonics, and the Instantaneous Shaft Rotational Frequency (ISRF) into straight lines, the bearing fault can be detected and diagnosed without resampling. However, so far, the extraction of the IFCF for bearing fault diagnosis is mostly based on the assumption that at each moment the IFCF has the highest amplitude in the TFR, which is not always true. Hence, a more reliable T-F curve extraction approach should be investigated. Moreover, if the T-F curves including the IFCF, its harmonic, and the ISRF can be all extracted from the TFR directly, no extra processing is needed for fault diagnosis. Therefore, this paper proposes an algorithm for multiple T-F curve extraction from the TFR based on a fast path optimization which is more reliable for T-F curve extraction. Then, a new procedure for bearing fault diagnosis under unknown time-varying speed conditions is developed based on the proposed algorithm and a new fault diagnosis strategy. The average curve-to-curve ratios are utilized to describe the relationship of the extracted curves and fault diagnosis can then be achieved by comparing the ratios to the fault characteristic coefficients. The effectiveness of the proposed method is validated by simulated and experimental signals.

Short-term acclimation to warmer temperatures accelerates leaf carbon exchange processes across plant types.

PubMed

Smith, Nicholas G; Dukes, Jeffrey S

2017-11-01

While temperature responses of photosynthesis and plant respiration are known to acclimate over time in many species, few studies have been designed to directly compare process-level differences in acclimation capacity among plant types. We assessed short-term (7 day) temperature acclimation of the maximum rate of Rubisco carboxylation (V cmax ), the maximum rate of electron transport (J max ), the maximum rate of phosphoenolpyruvate carboxylase carboxylation (V pmax ), and foliar dark respiration (R d ) in 22 plant species that varied in lifespan (annual and perennial), photosynthetic pathway (C 3 and C 4 ), and climate of origin (tropical and nontropical) grown under fertilized, well-watered conditions. In general, acclimation to warmer temperatures increased the rate of each process. The relative increase in different photosynthetic processes varied by plant type, with C 3 species tending to preferentially accelerate CO 2 -limited photosynthetic processes and respiration and C 4 species tending to preferentially accelerate light-limited photosynthetic processes under warmer conditions. R d acclimation to warmer temperatures caused a reduction in temperature sensitivity that resulted in slower rates at high leaf temperatures. R d acclimation was similar across plant types. These results suggest that temperature acclimation of the biochemical processes that underlie plant carbon exchange is common across different plant types, but that acclimation to warmer temperatures tends to have a relatively greater positive effect on the processes most limiting to carbon assimilation, which differ by plant type. The acclimation responses observed here suggest that warmer conditions should lead to increased rates of carbon assimilation when water and nutrients are not limiting. © 2017 John Wiley & Sons Ltd.

Costs of storing colour and complex shape in visual working memory: Insights from pupil size and slow waves.

PubMed

Kursawe, Michael A; Zimmer, Hubert D

2015-06-01

We investigated the impact of perceptual processing demands on visual working memory of coloured complex random polygons during change detection. Processing load was assessed by pupil size (Exp. 1) and additionally slow wave potentials (Exp. 2). Task difficulty was manipulated by presenting different set sizes (1, 2, 4 items) and by making different features (colour, shape, or both) task-relevant. Memory performance in the colour condition was better than in the shape and both condition which did not differ. Pupil dilation and the posterior N1 increased with set size independent of type of feature. In contrast, slow waves and a posterior P2 component showed set size effects but only if shape was task-relevant. In the colour condition slow waves did not vary with set size. We suggest that pupil size and N1 indicates different states of attentional effort corresponding to the number of presented items. In contrast, slow waves reflect processes related to encoding and maintenance strategies. The observation that their potentials vary with the type of feature (simple colour versus complex shape) indicates that perceptual complexity already influences encoding and storage and not only comparison of targets with memory entries at the moment of testing. Copyright © 2015 Elsevier B.V. All rights reserved.

Assessing the impact of graphical quality on automatic text recognition in digital maps

NASA Astrophysics Data System (ADS)

Chiang, Yao-Yi; Leyk, Stefan; Honarvar Nazari, Narges; Moghaddam, Sima; Tan, Tian Xiang

2016-08-01

Converting geographic features (e.g., place names) in map images into a vector format is the first step for incorporating cartographic information into a geographic information system (GIS). With the advancement in computational power and algorithm design, map processing systems have been considerably improved over the last decade. However, the fundamental map processing techniques such as color image segmentation, (map) layer separation, and object recognition are sensitive to minor variations in graphical properties of the input image (e.g., scanning resolution). As a result, most map processing results would not meet user expectations if the user does not "properly" scan the map of interest, pre-process the map image (e.g., using compression or not), and train the processing system, accordingly. These issues could slow down the further advancement of map processing techniques as such unsuccessful attempts create a discouraged user community, and less sophisticated tools would be perceived as more viable solutions. Thus, it is important to understand what kinds of maps are suitable for automatic map processing and what types of results and process-related errors can be expected. In this paper, we shed light on these questions by using a typical map processing task, text recognition, to discuss a number of map instances that vary in suitability for automatic processing. We also present an extensive experiment on a diverse set of scanned historical maps to provide measures of baseline performance of a standard text recognition tool under varying map conditions (graphical quality) and text representations (that can vary even within the same map sheet). Our experimental results help the user understand what to expect when a fully or semi-automatic map processing system is used to process a scanned map with certain (varying) graphical properties and complexities in map content.

Transfer behavior of odorous pollutants in wastewater sludge system under typical chemical conditioning processes for dewaterability enhancement.

PubMed

Gao, Hongyu; Zhang, Weijun; Song, Zhenzhen; Yang, Xiaofang; Yang, Lian; Cao, Mengdi; Wang, Dongsheng; Liao, Guiying

2017-06-13

Chemical conditioning has been used for enhancing wastewater sludge dewaterability for many years, but the characteristics of odorous pollutants emission in sludge conditioning were still unclear. In this work, the transfer behavior of different odorous pollutants between air, liquid and solid phases under typical chemical conditioning processes for high-pressure dewatering was systematically investigated. The results indicated that that besides hydrogen sulfide (H 2 S) and ammonia (NH 3 ), 21 kinds of volatile organic contaminants (VOCs) were identified and quantified by gas chromatography-mass spectrometry (GC-MS), while the concentrations and composition of odorous pollutants varied greatly for different conditioning processes. VOCs were composed by three main constituents including benzenes, halogeno benzene and hydrocarbons. According to mass balance analysis, about 50% of VOCs adsorbed within sludge extracellular polymeric substances (EPS) fraction. Since EPS was damaged and/or flocculation in different chemical conditioning processes, VOCs distributed in solid phase transformed into liquid phase and then released into air. The discrepancies in mass of odorous pollutants before and after chemical conditioning were likely to be related to chemical conversion under acidification, oxidation and precipitation in the presence of ferric ions.

Chemistry of rubber processing and disposal.

PubMed Central

Bebb, R L

1976-01-01

The major chemical changes during the processing of rubber occur with the breakdown in mastication and during vulcanization of the molded tire. There is little chemical change during the compounding, calendering, extrusion, and molding steps. Reclaiming is the process of converting scrap rubber into an unsaturated, processible product that can be vulcanized with sulfur. Pyrolysis of scrap rubber yields a complex mixture of liquids, gas, and residue in varying ratios dependent on the nature of the scrap and the conditions of pyrolysis. PMID:799964

Process-Structure Linkages Using a Data Science Approach: Application to Simulated Additive Manufacturing Data

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

Popova, Evdokia; Rodgers, Theron M.; Gong, Xinyi

A novel data science workflow is developed and demonstrated to extract process-structure linkages (i.e., reduced-order model) for microstructure evolution problems when the final microstructure depends on (simulation or experimental) processing parameters. Our workflow consists of four main steps: data pre-processing, microstructure quantification, dimensionality reduction, and extraction/validation of process-structure linkages. These methods that can be employed within each step vary based on the type and amount of available data. In this paper, this data-driven workflow is applied to a set of synthetic additive manufacturing microstructures obtained using the Potts-kinetic Monte Carlo (kMC) approach. Additive manufacturing techniques inherently produce complex microstructures thatmore » can vary significantly with processing conditions. Using the developed workflow, a low-dimensional data-driven model was established to correlate process parameters with the predicted final microstructure. In addition, the modular workflows developed and presented in this work facilitate easy dissemination and curation by the broader community.« less

Surface enhancement of cold work tool steels by friction stir processing with a pinless tool

NASA Astrophysics Data System (ADS)

Costa, M. I.; Verdera, D.; Vieira, M. T.; Rodrigues, D. M.

2014-03-01

The microstructure and mechanical properties of enhanced tool steel (AISI D2) surfaces produced using a friction stir welding (FSW) related procedure, called friction stir processing (FSP), are analysed in this work. The surface of the tool steel samples was processed using a WC-Co pinless tool and varying processing conditions. Microstructural analysis revealed that meanwhile the original substrate structure consisted of a heterogeneous distribution of coarse carbides in a ferritic matrix, the transformed surfaces consisted of very small carbides, homogenously distributed in a ferrite- bainite- martensite matrix. The morphology of the surfaces, as well as its mechanical properties, evaluated by hardness and tensile testing, were found to vary with increasing tool rotation speed. Surface hardness was drastically increased, relative to the initial hardness of bulk steel. This was attributed to ferrite and carbide refinement, as well as to martensite formation during solid state processing. At the highest rotation rates, tool sliding during processing deeply compromised the characteristics of the processed surfaces.

Process-Structure Linkages Using a Data Science Approach: Application to Simulated Additive Manufacturing Data

DOE PAGES

Popova, Evdokia; Rodgers, Theron M.; Gong, Xinyi; ...

2017-03-13

A novel data science workflow is developed and demonstrated to extract process-structure linkages (i.e., reduced-order model) for microstructure evolution problems when the final microstructure depends on (simulation or experimental) processing parameters. Our workflow consists of four main steps: data pre-processing, microstructure quantification, dimensionality reduction, and extraction/validation of process-structure linkages. These methods that can be employed within each step vary based on the type and amount of available data. In this paper, this data-driven workflow is applied to a set of synthetic additive manufacturing microstructures obtained using the Potts-kinetic Monte Carlo (kMC) approach. Additive manufacturing techniques inherently produce complex microstructures thatmore » can vary significantly with processing conditions. Using the developed workflow, a low-dimensional data-driven model was established to correlate process parameters with the predicted final microstructure. In addition, the modular workflows developed and presented in this work facilitate easy dissemination and curation by the broader community.« less

Definitions of climate and climate change under varying external conditions

NASA Astrophysics Data System (ADS)

Werndl, C.

2014-06-01

Commonly, definitions of climate are endorsed where the external conditions are held constant. This paper argues that these definitions risk being empirically void because in reality the external conditions vary. As a consequence, analogous definitions for varying external conditions are explored with help of the recently developed theory of non-autonomous dynamical systems, and the similarities and differences between the cases of constant and varying external conditions are discussed. It is argued that there are analogous definitions for varying external conditions which are preferable to the definitions where the external conditions are held constant. In this context, a novel definition is proposed (namely, climate as the distribution over time under a regime of varying external conditions), which is argued to be promising.

Different target-discrimination times can be followed by the same saccade-initiation timing in different stimulus conditions during visual searches

PubMed Central

Tanaka, Tomohiro; Nishida, Satoshi

2015-01-01

The neuronal processes that underlie visual searches can be divided into two stages: target discrimination and saccade preparation/generation. This predicts that the length of time of the prediscrimination stage varies according to the search difficulty across different stimulus conditions, whereas the length of the latter postdiscrimination stage is stimulus invariant. However, recent studies have suggested that the length of the postdiscrimination interval changes with different stimulus conditions. To address whether and how the visual stimulus affects determination of the postdiscrimination interval, we recorded single-neuron activity in the lateral intraparietal area (LIP) when monkeys (Macaca fuscata) performed a color-singleton search involving four stimulus conditions that differed regarding luminance (Bright vs. Dim) and target-distractor color similarity (Easy vs. Difficult). We specifically focused on comparing activities between the Bright-Difficult and Dim-Easy conditions, in which the visual stimuli were considerably different, but the mean reaction times were indistinguishable. This allowed us to examine the neuronal activity when the difference in the degree of search speed between different stimulus conditions was minimal. We found that not only prediscrimination but also postdiscrimination intervals varied across stimulus conditions: the postdiscrimination interval was longer in the Dim-Easy condition than in the Bright-Difficult condition. Further analysis revealed that the postdiscrimination interval might vary with stimulus luminance. A computer simulation using an accumulation-to-threshold model suggested that the luminance-related difference in visual response strength at discrimination time could be the cause of different postdiscrimination intervals. PMID:25995344

Developing a scalable model of recombinant protein yield from Pichia pastoris: the influence of culture conditions, biomass and induction regime

PubMed Central

Holmes, William J; Darby, Richard AJ; Wilks, Martin DB; Smith, Rodney; Bill, Roslyn M

2009-01-01

Background The optimisation and scale-up of process conditions leading to high yields of recombinant proteins is an enduring bottleneck in the post-genomic sciences. Typical experiments rely on varying selected parameters through repeated rounds of trial-and-error optimisation. To rationalise this, several groups have recently adopted the 'design of experiments' (DoE) approach frequently used in industry. Studies have focused on parameters such as medium composition, nutrient feed rates and induction of expression in shake flasks or bioreactors, as well as oxygen transfer rates in micro-well plates. In this study we wanted to generate a predictive model that described small-scale screens and to test its scalability to bioreactors. Results Here we demonstrate how the use of a DoE approach in a multi-well mini-bioreactor permitted the rapid establishment of high yielding production phase conditions that could be transferred to a 7 L bioreactor. Using green fluorescent protein secreted from Pichia pastoris, we derived a predictive model of protein yield as a function of the three most commonly-varied process parameters: temperature, pH and the percentage of dissolved oxygen in the culture medium. Importantly, when yield was normalised to culture volume and density, the model was scalable from mL to L working volumes. By increasing pre-induction biomass accumulation, model-predicted yields were further improved. Yield improvement was most significant, however, on varying the fed-batch induction regime to minimise methanol accumulation so that the productivity of the culture increased throughout the whole induction period. These findings suggest the importance of matching the rate of protein production with the host metabolism. Conclusion We demonstrate how a rational, stepwise approach to recombinant protein production screens can reduce process development time. PMID:19570229

Memory guidance in distractor suppression is governed by the availability of cognitive control.

PubMed

Wen, Wen; Hou, Yin; Li, Sheng

2018-03-26

Information stored in the memory systems can affect visual search. Previous studies have shown that holding the to-be-ignored features of distractors in working memory (WM) could accelerate target selection. However, such facilitation effect was only observed when the cued to-be-ignored features remained unchanged within an experimental block (i.e., the fixed cue condition). No search benefit was obtained if the to-be-ignored features varied from trial to trial (i.e., the varied cue condition). In the present study, we conducted three behavioral experiments to investigate whether the WM and long-term memory (LTM) representations of the to-be-ignored features could facilitate visual search in the fixed cue (Experiment 1) and varied cue (Experiments 2 and 3) conditions. Given the importance of the processing time of cognitive control in distractor suppression, we divided visual search trials into five quintiles based on their reaction times (RTs) and examined the temporal characteristics of the suppression effect. Results showed that both the WM and LTM representations of the to-be-ignored features could facilitate distractor suppression in the fixed cue condition, and the facilitation effects were evident across the quintiles in the RT distribution. However, in the varied cue condition, the RT benefits of the WM-matched distractors occurred only in the trials with the longest RTs, whereas no advantage of the LTM-matched distractors was observed. These results suggest that the effective WM-guided distractor suppression depends on the availability of cognitive control and the LTM-guided suppression occurs only if sufficient WM resource is accessible by LTM reactivation.

Evaluation of Process Performance for Sustainable Hard Machining

NASA Astrophysics Data System (ADS)

Rotella, Giovanna; Umbrello, Domenico; , Oscar W. Dillon, Jr.; Jawahir, I. S.

This paper aims to evaluate the sustainability performance of machining operation of through-hardening steel, AISI 52100, taking into account the impact of the material removal process in its various aspects. Experiments were performed for dry and cryogenic cutting conditions using chamfered cubic boron nitride (CBN) tool inserts at varying cutting conditions (cutting speed and feed rate). Cutting forces, mechanical power, tool wear, white layer thickness, surface roughness and residual stresses were investigated in order to evaluate the effects of extreme in-process cooling on the machined surface. The results indicate that cryogenic cooling has the potential to be used for surface integrity enhancement for improved product life and more sustainable functional performance.

Interactive effects in transfer-appropriate processing for event-based prospective memory: the roles of effort, ongoing task, and PM cue properties.

PubMed

Abney, Drew H; McBride, Dawn M; Petrella, Samantha N

2013-10-01

Past studies (e.g., Marsh, Hicks, & Cook Journal of Experimental Psychology: Learning, Memory, and Cognition 31:68-75, 2005; Meiser & Schult European Journal of Cognitive Psychology 20:290-311, 2008) have shown that transfer-appropriate processing (TAP) effects in event-based prospective memory (PM) depend on the effort directed toward the ongoing task. In the present study, we addressed mixed findings from these studies and examined monitoring in TAP and transfer-inappropriate processing (TIP) conditions. In two experiments, a semantic or orthographic ongoing task was paired with a PM cue that either was matched in processing (TAP) or did not match in processing (TIP). Within each condition, effort was varied across trials. The results indicated that PM accuracy was higher in TAP than in TIP conditions, regardless of effort condition, supporting the findings reported by Meiser and Schult. Ex-Gaussian functions were fit to the mean reaction times (cf. Brewer Journal of Psychology 219:117-124, 2011) in order to examine monitoring across conditions. The analysis of distributional skew (τ parameter) showed sensitivity to ongoing task instructions and properties of the PM cues. These results support Meiser and Schult's suggestion that TIP conditions require more attentional processing, and they also afford novel discussion on the interactive effects of ongoing task condition, PM cue properties, and manipulations of effort.

Analysis of automobile engine cylinder pressure and rotation speed from engine body vibration signal

NASA Astrophysics Data System (ADS)

Wang, Yuhua; Cheng, Xiang; Tan, Haishu

2016-01-01

In order to improve the engine vibration signal process method for the engine cylinder pressure and engine revolution speed measurement instrument, the engine cylinder pressure varying with the engine working cycle process has been regarded as the main exciting force for the engine block forced vibration. The forced vibration caused by the engine cylinder pressure presents as a low frequency waveform which varies with the cylinder pressure synchronously and steadily in time domain and presents as low frequency high energy discrete humorous spectrum lines in frequency domain. The engine cylinder pressure and the rotation speed can been extract form the measured engine block vibration signal by low-pass filtering analysis in time domain or by FFT analysis in frequency domain, the low-pass filtering analysis in time domain is not only suitable for the engine in uniform revolution condition but also suitable for the engine in uneven revolution condition. That provides a practical and convenient way to design motor revolution rate and cylinder pressure measurement instrument.

Slow-fast stochastic diffusion dynamics and quasi-stationarity for diploid populations with varying size.

PubMed

Coron, Camille

2016-01-01

We are interested in the long-time behavior of a diploid population with sexual reproduction and randomly varying population size, characterized by its genotype composition at one bi-allelic locus. The population is modeled by a 3-dimensional birth-and-death process with competition, weak cooperation and Mendelian reproduction. This stochastic process is indexed by a scaling parameter K that goes to infinity, following a large population assumption. When the individual birth and natural death rates are of order K, the sequence of stochastic processes indexed by K converges toward a new slow-fast dynamics with variable population size. We indeed prove the convergence toward 0 of a fast variable giving the deviation of the population from quasi Hardy-Weinberg equilibrium, while the sequence of slow variables giving the respective numbers of occurrences of each allele converges toward a 2-dimensional diffusion process that reaches (0,0) almost surely in finite time. The population size and the proportion of a given allele converge toward a Wright-Fisher diffusion with stochastically varying population size and diploid selection. We insist on differences between haploid and diploid populations due to population size stochastic variability. Using a non trivial change of variables, we study the absorption of this diffusion and its long time behavior conditioned on non-extinction. In particular we prove that this diffusion starting from any non-trivial state and conditioned on not hitting (0,0) admits a unique quasi-stationary distribution. We give numerical approximations of this quasi-stationary behavior in three biologically relevant cases: neutrality, overdominance, and separate niches.

Modeling of the non-isothermal crystallization kinetics of polyamide 6 composites during thermoforming

NASA Astrophysics Data System (ADS)

Kugele, Daniel; Dörr, Dominik; Wittemann, Florian; Hangs, Benjamin; Rausch, Julius; Kärger, Luise; Henning, Frank

2017-10-01

The combination of thermoforming processes of continuous-fiber reinforced thermoplastics and injection molding offers a high potential for cost-effective use in automobile mass production. During manufacturing, the thermoplastic laminates are initially heated up to a temperature above the melting point. This is followed by continuous cooling of the material during the forming process, which leads to crystallization under non-isothermal conditions. To account for phase change effects in thermoforming simulation, an accurate modeling of the crystallization kinetics is required. In this context, it is important to consider the wide range of cooling rates, which are observed during processing. Consequently, this paper deals with the experimental investigation of the crystallization at cooling rates varying from 0.16 K/s to 100 K/s using standard differential scanning calorimetry (DSC) and fast scanning calorimetry (Flash DSC). Two different modeling approaches (Nakamura model, modified Nakamura-Ziabicki model) for predicting crystallization kinetics are parameterized according to DSC measurements. It turns out that only the modified Nakamura-Ziabicki model is capable of predicting crystallization kinetics for all investigated cooling rates. Finally, the modified Nakamura-Ziabicki model is validated by cooling experiments using PA6-CF laminates with embedded temperature sensors. It is shown that the modified Nakamura-Ziabicki model predicts crystallization at non-isothermal conditions and varying cooling rates with a good accuracy. Thus, the study contributes to a deeper understanding of the non-isothermal crystallization and presents an overall method for modeling crystallization under process conditions.

Evaporation and transpiration

Treesearch

Robert R. Ziemer

1979-01-01

For years, the principal objective of evapotranspiration research has been to calculate the loss of water under varying conditions of climate, soil, and vegetation. The early simple empirical methods have generally been replaced by more detailed models which more closely represent the physical and biological processes involved. Monteith's modification of the...

Soot and Spectral Radiation Modeling in ECN Spray A and in Engines

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

Haworth, Daniel C; Ferreyro-Fernandez, Sebastian; Paul, Chandan

The amount of soot formed in a turbulent combustion system is determined by a complex system of coupled nonlinear chemical and physical processes. Different physical subprocesses can dominate, depending on the hydrodynamic and thermochemical environments. Similarly, the relative importance of reabsorption, spectral radiation properties, and molecular gas radiation versus soot radiation varies with thermochemical conditions, and in ways that are difficult to predict for the highly nonhomogeneous in-cylinder mixtures in engines. Here it is shown that transport and mixing play relatively more important roles as rate-determining processes in soot formation at engine-relevant conditions. It is also shown that molecular gasmore » radiation and spectral radiation properties are important for engine-relevant conditions.« less

Hybrid Percolation Transition in Cluster Merging Processes: Continuously Varying Exponents

NASA Astrophysics Data System (ADS)

Cho, Y. S.; Lee, J. S.; Herrmann, H. J.; Kahng, B.

2016-01-01

Consider growing a network, in which every new connection is made between two disconnected nodes. At least one node is chosen randomly from a subset consisting of g fraction of the entire population in the smallest clusters. Here we show that this simple strategy for improving connection exhibits a more unusual phase transition, namely a hybrid percolation transition exhibiting the properties of both first-order and second-order phase transitions. The cluster size distribution of finite clusters at a transition point exhibits power-law behavior with a continuously varying exponent τ in the range 2 <τ (g )≤2.5 . This pattern reveals a necessary condition for a hybrid transition in cluster aggregation processes, which is comparable to the power-law behavior of the avalanche size distribution arising in models with link-deleting processes in interdependent networks.

The effects of concurrent cognitive load on phonological processing in adults who stutter.

PubMed

Jones, Robin M; Fox, Robert A; Jacewicz, Ewa

2012-12-01

To determine whether phonological processing in adults who stutter (AWS) is disrupted by increased amounts of cognitive load in a concurrent attention-demanding task. Nine AWS and 9 adults who do not stutter (AWNS) participated. Using a dual-task paradigm, the authors presented word pairs for rhyme judgments and, concurrently, letter strings for memory recall. The rhyme judgment task manipulated rhyming type (rhyming/nonrhyming) and orthographic representation (similar/dissimilar). The memory recall task varied stimulus complexity (no letters, 3 letters, 5 letters). Rhyme judgment accuracy and reaction time (RT) were used to assess phonological processing, and letter recall accuracy was used to measure memory recall. For rhyme judgments, AWS were as accurate as AWNS, and the increase in the cognitive load did not affect rhyme judgment accuracy of either group. Significant group differences were found in RTs (delays by AWS were 241 ms greater). RTs of AWS were also slower in the most demanding rhyme condition and varied with the complexity of the memory task. Accuracy of letter recall of AWS was comparatively worse in the most demanding 5-letter condition. Phonological and cognitive processing of AWS is more vulnerable to disruptions caused by increased amounts of cognitive load in concurrent attention-demanding tasks.

Unattended processing of hierarchical pitch variations in spoken sentences.

PubMed

Li, Xiaoqing; Chen, Yiya

2018-05-16

An auditory oddball paradigm was employed to examine the unattended processing of pitch variation which functions to signal hierarchically different levels of meaning contrasts. Four oddball conditions were constructed by varying the pitch contour of critical words embedded in a Mandarin Chinese sentence. Two conditions included lexical-level word meaning contrasts (i.e. TONE condition) and the other two sentence-level information-status contrasts (i.e. ACCENTUATION condition). Both included stimuli with early vs. late acoustic cue divergence points. Results showed that the two early-cue conditions elicited earlier Mismatch Negativities, regardless of their functional hierarchy. The deviant stimuli induced theta-band power increases in the TONE condition but beta-band power decreases in the ACCENTUATIION condition, regardless of the timing of their acoustic cues. These results suggest that, in an unattentive state, the human brain can functionally disentangle hierarchically different levels of pitch variation, and the brain responses to these pitch variations are time-locked to the presence of the acoustic cues. Copyright © 2018. Published by Elsevier Inc.

A study of the relationship between the performance and dependability of a fault-tolerant computer

NASA Technical Reports Server (NTRS)

Goswami, Kumar K.

1994-01-01

This thesis studies the relationship by creating a tool (FTAPE) that integrates a high stress workload generator with fault injection and by using the tool to evaluate system performance under error conditions. The workloads are comprised of processes which are formed from atomic components that represent CPU, memory, and I/O activity. The fault injector is software-implemented and is capable of injecting any memory addressable location, including special registers and caches. This tool has been used to study a Tandem Integrity S2 Computer. Workloads with varying numbers of processes and varying compositions of CPU, memory, and I/O activity are first characterized in terms of performance. Then faults are injected into these workloads. The results show that as the number of concurrent processes increases, the mean fault latency initially increases due to increased contention for the CPU. However, for even higher numbers of processes (less than 3 processes), the mean latency decreases because long latency faults are paged out before they can be activated.

Consolidation of an extinction memory depends on the unconditioned stimulus magnitude previously experienced during training.

PubMed

Stollhoff, Nicola; Eisenhardt, Dorothea

2009-07-29

Here, we examine the role of the magnitude of the unconditioned stimulus (US) during classical conditioning in consolidation processes after memory retrieval. We varied the US durations during training and we test the impact of these variations on consolidation after memory retrieval with one or two conditioned stimulus-only trials. We found that the consolidation of an extinction memory depends on US duration during training and ruled out the possibility that this effect is attributable to differences in satiation after conditioning. We conclude that consolidation of an extinction memory is triggered only when the duration of the US reaches a critical threshold. This demonstrates that memory consolidation cannot be regarded as an isolated process depending solely on training conditions. Instead, it depends on the animal's previous experience as well.

Watershed Health: The Need for a New Perspective

NASA Astrophysics Data System (ADS)

Reeves, G.

2017-12-01

Watershed health is a measure of the condition of the aquatic ecosystem within a watershed and is indicated by a specific set of environmental conditions that provide desired ecological, social, and legal amenities. A watershed is deemed "healthy" if it has these attributes and the traditional management approach to maintaining or developing a healthy watershed is to create and maintain these specific conditions within the watershed. However, this approach may not be applicable to situations in which processes are complex, non-linear, and poorly understood. The focus on a specific set of conditions comes at the expense of recognizing the ecological processes that create and maintain habitats for an aquatic organisms and the ecological context in which they evolved, and may lead to further degradation or compromising of the ecosystems and landscapes of interest. An emerging perspective suggests that aquatic-riparian ecosystems possess a range of processes and attributes that are inherently complex, nonlinear, and dynamic and because of the variation in the size and asynchronous nature of disturbance events, conditions will vary over time among watersheds, resulting in a mosaic of biophysical conditions across the landscape. Thus, watershed health may not be a single condition but rather a suite of conditions similar to how terrestrial ecosystems are viewed, requiring an integrated assessment of a range of ecological conditions and consideration of the intactness of key ecological processes.

System and method for statistically monitoring and analyzing sensed conditions

DOEpatents

Pebay, Philippe P [Livermore, CA; Brandt, James M [Dublin, CA; Gentile, Ann C [Dublin, CA; Marzouk, Youssef M [Oakland, CA; Hale, Darrian J [San Jose, CA; Thompson, David C [Livermore, CA

2011-01-04

A system and method of monitoring and analyzing a plurality of attributes for an alarm condition is disclosed. The attributes are processed and/or unprocessed values of sensed conditions of a collection of a statistically significant number of statistically similar components subjected to varying environmental conditions. The attribute values are used to compute the normal behaviors of some of the attributes and also used to infer parameters of a set of models. Relative probabilities of some attribute values are then computed and used along with the set of models to determine whether an alarm condition is met. The alarm conditions are used to prevent or reduce the impact of impending failure.

System and method for statistically monitoring and analyzing sensed conditions

DOEpatents

Pebay, Philippe P [Livermore, CA; Brandt, James M [Dublin, CA; Gentile, Ann C [Dublin, CA; Marzouk, Youssef M [Oakland, CA; Hale, Darrian J [San Jose, CA; Thompson, David C [Livermore, CA

2011-01-25

A system and method of monitoring and analyzing a plurality of attributes for an alarm condition is disclosed. The attributes are processed and/or unprocessed values of sensed conditions of a collection of a statistically significant number of statistically similar components subjected to varying environmental conditions. The attribute values are used to compute the normal behaviors of some of the attributes and also used to infer parameters of a set of models. Relative probabilities of some attribute values are then computed and used along with the set of models to determine whether an alarm condition is met. The alarm conditions are used to prevent or reduce the impact of impending failure.

System and method for statistically monitoring and analyzing sensed conditions

DOEpatents

Pebay, Philippe P [Livermore, CA; Brandt, James M. , Gentile; Ann C. , Marzouk; Youssef M. , Hale; Darrian J. , Thompson; David, C [Livermore, CA

2010-07-13

A system and method of monitoring and analyzing a plurality of attributes for an alarm condition is disclosed. The attributes are processed and/or unprocessed values of sensed conditions of a collection of a statistically significant number of statistically similar components subjected to varying environmental conditions. The attribute values are used to compute the normal behaviors of some of the attributes and also used to infer parameters of a set of models. Relative probabilities of some attribute values are then computed and used along with the set of models to determine whether an alarm condition is met. The alarm conditions are used to prevent or reduce the impact of impending failure.

Estimating effective soil properties of heterogeneous areas for modeling infiltration and redistribution

USDA-ARS?s Scientific Manuscript database

Field scale water infiltration and soil-water and solute transport models require spatially-averaged “effective” soil hydraulic parameters to represent the average flux and storage. The values of these effective parameters vary for different conditions, processes, and component soils in a field. For...

Enhanced processing of threat stimuli under limited attentional resources.

PubMed

De Martino, Benedetto; Kalisch, Raffael; Rees, Geraint; Dolan, Raymond J

2009-01-01

The ability to process stimuli that convey potential threat, under conditions of limited attentional resources, confers adaptive advantages. This study examined the neurobiology underpinnings of this capacity. Employing an attentional blink paradigm, in conjunction with functional magnetic resonance imaging, we manipulated the salience of the second of 2 face target stimuli (T2), by varying emotionality. Behaviorally, fearful T2 faces were identified significantly more than neutral faces. Activity in fusiform face area increased with correct identification of T2 faces. Enhanced activity in rostral anterior cingulate cortex (rACC) accounted for the benefit in detection of fearful stimuli reflected in a significant interaction between target valence and correct identification. Thus, under conditions of limited attention resources activation in rACC correlated with enhanced processing of emotional stimuli. We suggest that these data support a model in which a prefrontal "gate" mechanism controls conscious access of emotional information under conditions of limited attentional resources.

Development of optimum process for electron beam cross-linking of high density polyethylene thermal energy storage pellets, process scale-up and production of application qualities of material

NASA Technical Reports Server (NTRS)

Salyer, I. O.

1980-01-01

The electron irradiation conditions required to prepare thermally from stable high density polyethylene (HDPE) were defined. The conditions were defined by evaluating the heat of fusion and the melting temperature of several HDPE specimens. The performance tests conducted on the specimens, including the thermal cycling tests in the thermal energy storage unit are described. The electron beam irradiation tests performed on the specimens, in which the total radiation dose received by the pellets, the electron beam current, the accelerating potential, and the atmospheres were varied, are discussed.

Tracing Nitrogen Sources in Forested Catchments Under Varying Flow Conditions: Seasonal and Event Scale Patterns

NASA Astrophysics Data System (ADS)

Sebestyen, S. D.; Shanley, J. B.; Boyer, E. W.; Kendall, C.

2004-12-01

Our ability to assess how stream nutrient concentrations respond to biogeochemical transformations and stream flow dynamics is often limited by datasets that do not include all flow conditions that occur over event, monthly, seasonal, and yearly time scales. At the Sleepers River Research Watershed in northeastern Vermont, USA, nitrate, DOC (dissolved organic carbon), and major ion concentrations were measured on samples collected over a wide range of flow conditions from summer 2002 through summer 2004. Nutrient flushing occurred at the W-9 catchment and high-frequency sampling revealed critical insights into seasonal and event-scale controls on nutrient concentrations. In this seasonally snow-covered catchment, the earliest stage of snowmelt introduced nitrogen directly to the stream from the snowpack. As snowmelt progressed, the source of stream nitrate shifted to flushing of soil nitrate along shallow subsurface flow paths. In the growing season, nitrogen flushing to streams varied with antecedent moisture conditions. More nitrogen was available to flush to streams when antecedent moisture was lowest, and mobile nitrogen stores in the landscape regenerated under baseflow conditions on times scales as short as 7 days. Leaf fall was another critical time when coupled hydrological and biogeochemical processes controlled nutrient fluxes. With the input of labile organic carbon from freshly decomposing leaves, nitrate concentrations declined sharply in response to in-stream immobilization or denitrification. These high-resolution hydrochemical data from multiple flow regimes are identifying "hot spots" and "hot moments" of biogeochemical and hydrological processes that control nutrient fluxes in streams.

Finding a face in the crowd: testing the anger superiority effect in Asperger Syndrome.

PubMed

Ashwin, Chris; Wheelwright, Sally; Baron-Cohen, Simon

2006-06-01

Social threat captures attention and is processed rapidly and efficiently, with many lines of research showing involvement of the amygdala. Visual search paradigms looking at social threat have shown angry faces 'pop-out' in a crowd, compared to happy faces. Autism and Asperger Syndrome (AS) are neurodevelopmental conditions characterised by social deficits, abnormal face processing, and amygdala dysfunction. We tested adults with high-functioning autism (HFA) and AS using a facial visual search paradigm with schematic neutral and emotional faces. We found, contrary to predictions, that people with HFA/AS performed similarly to controls in many conditions. However, the effect was reduced in the HFA/AS group when using widely varying crowd sizes and when faces were inverted, suggesting a difference in face-processing style may be evident even with simple schematic faces. We conclude there are intact threat detection mechanisms in AS, under simple and predictable conditions, but that like other face-perception tasks, the visual search of threat faces task reveals atypical face-processing in HFA/AS.

Acoustic emission characteristics of a single cylinder diesel generator at various loads and with a failing injector

NASA Astrophysics Data System (ADS)

Dykas, Brian; Harris, James

2017-09-01

Acoustic emission sensing techniques have been applied in recent years to dynamic machinery with varying degrees of success in diagnosing various component faults and distinguishing between operating conditions. This work explores basic properties of acoustic emission signals measured on a small single cylinder diesel engine in a laboratory setting. As reported in other works in the open literature, the measured acoustic emission on the engine is mostly continuous mode and individual burst events are generally not readily identifiable. Therefore, the AE are processed into the local (instantaneous) root mean square (rms) value of the signal which is averaged over many cycles to obtain a mean rms AE in the crank angle domain. Crank-resolved spectral representation of the AE is also given but rigorous investigation of the AE spectral qualities is left to future study. Cycle-to-cycle statistical dispersion of the AE signal is considered to highlight highly variable engine processes. Engine speed was held constant but load conditions are varied to investigate AE signal sensitivity to operating condition. Furthermore, during the course of testing the fuel injector developed a fault and acoustic emission signals were captured and several signal attributes were successful in distinguishing this altered condition. The sampling and use of instantaneous rms acoustic emission signal demonstrated promise for non-intrusive and economical change detection of engine injection, combustion and valve events.

Doping and structural properties for the phosphorous-doped polysilicon layers used for micromechanical applications

NASA Astrophysics Data System (ADS)

Gaiseanu, Florin; Esteve, Jaume; Cane, Carles; Perez-Rodriguez, Alejandro; Morante, Juan R.; Serre, Christoph

1999-08-01

Our researches were devoted to the micromechanical elements fabricated by the surface micromachining technology, in order to reduce or to eliminate the internal stress or the stress gradients. We used an analysis based on secondary ion mass spectroscopy and the spreading resistance profiling determinations, correlated with cross-section electron transmission spectroscopy. The stress induced in the polysilicon layers by the technological processes depends on: (i) the conditions of the low pressure chemical vapor deposition process; (ii) the phosphorus doping technique; (iii) the subsequent multi-step annealing processes. In our experiments the LP-CVD conditions were maintained the same, but the condition specified previously as items (ii) was varied by using two different doping techniques: thermal- chemical doping consisting in prediffusion from a POCl3 source in an open furnace tube; ionic implantation with an energy E equals 65KeV and a dose N equals 4.5 X 1015 cm-2. The implantation process was followed by an annealing at 900 degrees C in an oxygen ambient for 30 minutes. The thermal budget was varied after the doping in order to reduce the stress gradient in the polysilicon layers. The results of our analysis allow us to show that: (1) the doping gradients are correlated with the slower phosphorus grains forme by an excess of the oxygen atoms; a concurrent process induced by the silicon self-interstitial injection during the diffusion and oxidation, determines the enhancement of the grain growth and therefore the enhancement of the electrical activation especially near the internal polysilicon interface; (2) the post-doping annealing conditions could be varied in a convenient manner, so that the doping induced stress gradients into the polysilicon layers to be reduced or completely eliminated for suitable micromechanical induced stress gradients into the polysilicon layers to be reduced or completely eliminated for suitable micromechanical applications. The results were used for the process optimization of micromechanical elements. The internal stress was determined by using anew, pull-in voltage method, allowing the comparison of the theory with the experimental data. It was deduced a new form of the equations set useful to extract the mechanical parameters like the internal stress and the Young's module. It was also deduced a simplified approximate formula useful to apply the least square fitting method for the extraction of the mechanical parameters. The results confirms the conclusions of the doping and the structural analysis.

Method of preparing uranium nitride or uranium carbonitride bodies

DOEpatents

Wilhelm, Harley A.; McClusky, James K.

1976-04-27

Sintered uranium nitride or uranium carbonitride bodies having a controlled final carbon-to-uranium ratio are prepared, in an essentially continuous process, from U.sub.3 O.sub.8 and carbon by varying the weight ratio of carbon to U.sub.3 O.sub.8 in the feed mixture, which is compressed into a green body and sintered in a continuous heating process under various controlled atmospheric conditions to prepare the sintered bodies.

The Downside of Greater Lexical Influences: Selectively Poorer Speech Perception in Noise

PubMed Central

Xie, Zilong; Tessmer, Rachel; Chandrasekaran, Bharath

2017-01-01

Purpose Although lexical information influences phoneme perception, the extent to which reliance on lexical information enhances speech processing in challenging listening environments is unclear. We examined the extent to which individual differences in lexical influences on phonemic processing impact speech processing in maskers containing varying degrees of linguistic information (2-talker babble or pink noise). Method Twenty-nine monolingual English speakers were instructed to ignore the lexical status of spoken syllables (e.g., gift vs. kift) and to only categorize the initial phonemes (/g/ vs. /k/). The same participants then performed speech recognition tasks in the presence of 2-talker babble or pink noise in audio-only and audiovisual conditions. Results Individuals who demonstrated greater lexical influences on phonemic processing experienced greater speech processing difficulties in 2-talker babble than in pink noise. These selective difficulties were present across audio-only and audiovisual conditions. Conclusion Individuals with greater reliance on lexical processes during speech perception exhibit impaired speech recognition in listening conditions in which competing talkers introduce audible linguistic interferences. Future studies should examine the locus of lexical influences/interferences on phonemic processing and speech-in-speech processing. PMID:28586824

Effect of manufacturing and experimental conditions on the mechanical and surface properties of silicone elastomer scaffolds used in endothelial mechanobiological studies.

PubMed

Campeau, Marc-Antoine; Lortie, Audrey; Tremblay, Pierrick; Béliveau, Marc-Olivier; Dubé, Dominic; Langelier, Ève; Rouleau, Léonie

2017-07-14

Mechanobiological studies allow the characterization of cell response to mechanical stresses. Cells need to be supported by a material with properties similar to the physiological environment. Silicone elastomers have been used to produce various in vitro scaffolds of different geometries for endothelial cell studies given its relevant mechanical, optical and surface properties. However, obtaining defined and repeatable properties is a challenge as depending on the different manufacturing and processing steps, mechanical and surface properties may vary significantly between research groups. The impact of different manufacturing and processing methods on the mechanical and surface properties was assessed by measuring the Young's modulus and the contact angle. Silicone samples were produced using different curing temperatures and processed with different sterilization techniques and hydrophilization conditions. Different curing temperatures were used to obtain materials of different stiffness with a chosen silicone elastomer, i.e. Sylgard 184 ® . Sterilization by boiling had a tendency to stiffen samples cured at lower temperatures whereas UV and ethanol did not alter the material properties. Hydrophilization using sulphuric acid allowed to decrease surface hydrophobicity, however this effect was lost over time as hydrophobic recovery occurred. Extended contact with water maintained decreased hydrophobicity up to 7 days. Mechanobiological studies require complete cell coverage of the scaffolds used prior to mechanical stresses exposure. Different concentrations of fibronectin and collagen were used to coat the scaffolds and cell seeding density was varied to optimize cell coverage. This study highlights the potential bias introduced by manufacturing and processing conditions needed in the preparation of scaffolds used in mechanobiological studies involving endothelial cells. As manufacturing, processing and cell culture conditions are known to influence cell adhesion and function, they should be more thoroughly assessed by research groups that perform such mechanobiological studies using silicone.

Business Process Design Method Based on Business Event Model for Enterprise Information System Integration

NASA Astrophysics Data System (ADS)

Kobayashi, Takashi; Komoda, Norihisa

The traditional business process design methods, in which the usecase is the most typical, have no useful framework to design the activity sequence with. Therefore, the design efficiency and quality vary widely according to the designer’s experience and skill. In this paper, to solve this problem, we propose the business events and their state transition model (a basic business event model) based on the language/action perspective, which is the result in the cognitive science domain. In the business process design, using this model, we decide event occurrence conditions so that every event synchronizes with each other. We also propose the design pattern to decide the event occurrence condition (a business event improvement strategy). Lastly, we apply the business process design method based on the business event model and the business event improvement strategy to the credit card issue process and estimate its effect.

Efficient extraction strategies of tea (Camellia sinensis) biomolecules.

PubMed

Banerjee, Satarupa; Chatterjee, Jyotirmoy

2015-06-01

Tea is a popular daily beverage worldwide. Modulation and modifications of its basic components like catechins, alkaloids, proteins and carbohydrate during fermentation or extraction process changes organoleptic, gustatory and medicinal properties of tea. Through these processes increase or decrease in yield of desired components are evident. Considering the varied impacts of parameters in tea production, storage and processes that affect the yield, extraction of tea biomolecules at optimized condition is thought to be challenging. Implementation of technological advancements in green chemistry approaches can minimize the deviation retaining maximum qualitative properties in environment friendly way. Existed extraction processes with optimization parameters of tea have been discussed in this paper including its prospects and limitations. This exhaustive review of various extraction parameters, decaffeination process of tea and large scale cost effective isolation of tea components with aid of modern technology can assist people to choose extraction condition of tea according to necessity.

Imperium/Lanzatech Syngas Fermentation Project - Biomass Gasification and Syngas Conditioning for Fermentation Evaluation: Cooperative Research and Development Final Report, CRADA Number CRD-12-474

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

Wilcox, E.

2014-09-01

LanzaTech and NREL will investigate the integration between biomass gasification and LanzaTech's proprietary gas fermentation process to produce ethanol and 2,3-butanediol. Using three feed materials (woody biomass, agricultural residue and herbaceous grass) NREL will produce syngas via steam indirect gasification and syngas conditioning over a range of process relevant operating conditions. The gasification temperature, steam-to-biomass ratio of the biomass feed into the gasifier, and several levels of syngas conditioning (based on temperature) will be varied to produce multiple syngas streams that will be fed directly to 10 liter seed fermenters operating with the Lanzatech organism. The NREL gasification system willmore » then be integrated with LanzaTech's laboratory pilot unit to produce large-scale samples of ethanol and 2,3-butanediol for conversion to fuels and chemicals.« less

Self-assembly of concentric quantum double rings.

PubMed

Mano, Takaaki; Kuroda, Takashi; Sanguinetti, Stefano; Ochiai, Tetsuyuki; Tateno, Takahiro; Kim, Jongsu; Noda, Takeshi; Kawabe, Mitsuo; Sakoda, Kazuaki; Kido, Giyuu; Koguchi, Nobuyuki

2005-03-01

We demonstrate the self-assembled formation of concentric quantum double rings with high uniformity and excellent rotational symmetry using the droplet epitaxy technique. Varying the growth process conditions can control each ring's size. Photoluminescence spectra emitted from an individual quantum ring complex show peculiar quantized levels that are specified by the carriers' orbital trajectories.

Heuristic and Analytic Processing: Age Trends and Associations with Cognitive Ability and Cognitive Styles.

ERIC Educational Resources Information Center

Kokis, Judite V.; Macpherson, Robyn; Toplak, Maggie E.; West, Richard F.; Stanovich, Keith E.

2002-01-01

Examined developmental and individual differences in tendencies to favor analytic over heuristic responses in three tasks (inductive reasoning, deduction under belief bias conditions, probabilistic reasoning) in children varying in age and cognitive ability. Found significant increases in analytic responding with development on first two tasks.…

Hierarchical Bayes Models for Response Time Data

ERIC Educational Resources Information Center

Craigmile, Peter F.; Peruggia, Mario; Van Zandt, Trisha

2010-01-01

Human response time (RT) data are widely used in experimental psychology to evaluate theories of mental processing. Typically, the data constitute the times taken by a subject to react to a succession of stimuli under varying experimental conditions. Because of the sequential nature of the experiments there are trends (due to learning, fatigue,…

Fire regimes, past and present

Treesearch

Carl N. Skinner; Chiru Chang

1996-01-01

Fire has been an important ecosystem process in the Sierra Nevada for thousands of years. Before the area was settled in the 1850s, fires were generally frequent throughout much of the range. The frequency and severity of these fires varied spatially and temporally depending upon climate, elevation, topography, vegetation, edaphic conditions, and human cultural...

Children's Judgements concerning "Easy" Partitioning. Tasks as Related to a Theory of Partitioning.

ERIC Educational Resources Information Center

Pothier, Yvonne; Sawada, Daiyo

By varying task conditions and constraints on subjects, this study attempted to extend and refine a developmental theory of partitioning as a foundational process undergirding children's construction of a rational number. Subjects were 31 preponderantly higher-grade pupils enrolled at an elementary school in Nova Scotia, Canada. Two tasks were…

Nonlinear dynamics in ecosystem response to climatic change: case studies and policy implications.

Treesearch

Virginia R. Burkett; Douglas A. Wilcox; Robert Stottlemeyer; Wylie Barrow; Dan Fagre; Jill Baron; Jeff Price; Jennifer L. Nielsen; Craig D. Allen; David L. Peterson; Greg Ruggerone; Thomas Doyle

2005-01-01

Many biological, hydrological, and geological processes are interactively linked in ecosystems. These ecological phenomena normally vary within bounded ranges, but rapid, nonlinear changes to markedly different conditions can be triggered by even small differences if threshold values are exceeded. Intrinsic and extrinsic ecological thresholds can lead to effects that...

The Effect of Reading Upon Pupil Dilation. Final Report.

ERIC Educational Resources Information Center

Carver, Ronald P.

The question of whether pupil diameter indicates information processing load during reading was investigated in three experiments involving 24 college students reading passages of varying difficulty. A TV camera and monitor, together with a video-recorder, were used to measure the diameter of the pupil under a reading condition and under three…

Application of a conceptional framework to interpret variability in rangeland responses to atmospheric CO2 enrichment

USDA-ARS?s Scientific Manuscript database

Plant productivity and other ecosystem processes vary widely in their responses to experimental increases in atmospheric carbon dioxide (CO2) concentration. We adapt a conceptual framework first suggested by Chapin et al. (1996) to define conditions that sustain ecosystems to address the question o...

Automated mosaicking of sub-canopy video incorporating ancillary data

Treesearch

E. Kee; N.E. Clark; A.L. Abbott

2002-01-01

This work investigates the process of mosaicking overlapping video frames of individual tree stems in sub-canopy scenes captured with a portable multisensor instrument. The robust commercial computer vision systems that are in use today typically rely on precisely controlled conditions. Inconsistent lighting as well as image distortion caused by varying interior and...

Experimental study of switching in a rho-i(MQW)-eta vertical coupler

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

Cavailles, J.A.; Erman, M.; Woodbridge, K.

1989-11-01

Electrically controlled switching in a vertically arranged directional coupler with GaAs/GaAIAs multiple quantum well waveguides is demonstrated. Coupling lengths and extinction parameters are determined by using a sample processed in such a way that injection conditions are well defined and that the coupler length can be varied continuously.

DOC quantity and quality in northeastern USA catchments

NASA Astrophysics Data System (ADS)

Shanley, J. B.; Sebestyen, S. D.; Aiken, G.; Pellerin, B. A.

2011-12-01

At the Sleepers River Research Watershed in Vermont we have studied interactions of dissolved organic carbon (DOC) cycling and hydrological processes for nearly 20 years to determine how and when DOC is transported through the landscape. Stream DOC concentration in this cool temperate forested catchment varies from ~1 to ~15 mg L-1 and is transport-limited; concentrations increase with increasing flow, even under the wettest conditions, suggesting shifting but non-depletable sources. Specific UV absorbance (SUVA) also increases consistently with flow. Source strength does vary seasonally, however, evidenced by higher DOC for a given flow during autumn leaf fall relative to spring snowmelt. Recent high-frequency optical sensor measurements have revealed fine-scale structure in the temporal DOC pattern not possible from discrete sampling. We observe a consistent counterclockwise hysteresis and diurnal cycles with seasonally variable amplitude. In this presentation we infer DOC sources and processes through analysis of antecedent moisture conditions and concurrent variations in nitrate, dissolved organic nitrogen, and SUVA. With sensors and sampling in place at several other research catchments, we are investigating the similarity of patterns across the northeastern USA.

Transesterification of waste vegetable oil under pulse sonication using ethanol, methanol and ethanol-methanol mixtures.

PubMed

Martinez-Guerra, Edith; Gude, Veera Gnaneswar

2014-12-01

This study reports on the effects of direct pulse sonication and the type of alcohol (methanol and ethanol) on the transesterification reaction of waste vegetable oil without any external heating or mechanical mixing. Biodiesel yields and optimum process conditions for the transesterification reaction involving ethanol, methanol, and ethanol-methanol mixtures were evaluated. The effects of ultrasonic power densities (by varying sample volumes), power output rates (in W), and ultrasonic intensities (by varying the reactor size) were studied for transesterification reaction with ethanol, methanol and ethanol-methanol (50%-50%) mixtures. The optimum process conditions for ethanol or methanol based transesterification reaction of waste vegetable oil were determined as: 9:1 alcohol to oil ratio, 1% wt. catalyst amount, 1-2 min reaction time at a power output rate between 75 and 150 W. It was shown that the transesterification reactions using ethanol-methanol mixtures resulted in biodiesel yields as high as >99% at lower power density and ultrasound intensity when compared to ethanol or methanol based transesterification reactions. Copyright © 2014 Elsevier Ltd. All rights reserved.

The development of sentence interpretation: effects of perceptual, attentional and semantic interference.

PubMed

Leech, Robert; Aydelott, Jennifer; Symons, Germaine; Carnevale, Julia; Dick, Frederic

2007-11-01

How does the development and consolidation of perceptual, attentional, and higher cognitive abilities interact with language acquisition and processing? We explored children's (ages 5-17) and adults' (ages 18-51) comprehension of morphosyntactically varied sentences under several competing speech conditions that varied in the degree of attentional demands, auditory masking, and semantic interference. We also evaluated the relationship between subjects' syntactic comprehension and their word reading efficiency and general 'speed of processing'. We found that the interactions between perceptual and attentional processes and complex sentence interpretation changed considerably over the course of development. Perceptual masking of the speech signal had an early and lasting impact on comprehension, particularly for more complex sentence structures. In contrast, increased attentional demand in the absence of energetic auditory masking primarily affected younger children's comprehension of difficult sentence types. Finally, the predictability of syntactic comprehension abilities by external measures of development and expertise is contingent upon the perceptual, attentional, and semantic milieu in which language processing takes place.

Differential contribution of left and right prefrontal cortex to associative cued-recall memory: a parametric PET study.

PubMed

Lepage, Martin

2004-03-01

Several brain imaging studies have implicated prefrontal regions bilaterally during cued-recall memory tasks and yet the functional significance of these regions remains poorly understood. Using PET, we examined the neural activity in prefrontal regions of 15 subjects while they performed three cued-recall tasks differing in pre-experimental semantic associations between cues and targets. This manipulation produced varying levels of retrieval performance when one member (a semantic category name) of the triad was used as a cue for the retrieval of the other two members. The percentage of items correctly recalled was 10, 46, and 70 in the low, medium, and high cued-recall conditions, respectively. Linear contrast analyses of the PET data identified brain regions where neural activity varied with the number of items retrieved from memory. A left lateral prefrontal region showed maximal activity during the high cued-recall condition, which likely reflects processes involved in retrieval success and possibly in the generation of memory responses. Three right prefrontal regions (anterior and dorsolateral) showed maximal activity during the low cued-recall condition, which likely reflects processes involved in memory search/monitoring. These findings add further support for a bilateral prefrontal contribution to memory cued-recall tasks and point to differential roles of the two hemispheres.

Structural acoustic control of plates with variable boundary conditions: design methodology.

PubMed

Sprofera, Joseph D; Cabell, Randolph H; Gibbs, Gary P; Clark, Robert L

2007-07-01

A method for optimizing a structural acoustic control system subject to variations in plate boundary conditions is provided. The assumed modes method is used to build a plate model with varying levels of rotational boundary stiffness to simulate the dynamics of a plate with uncertain edge conditions. A transducer placement scoring process, involving Hankel singular values, is combined with a genetic optimization routine to find spatial locations robust to boundary condition variation. Predicted frequency response characteristics are examined, and theoretically optimized results are discussed in relation to the range of boundary conditions investigated. Modeled results indicate that it is possible to minimize the impact of uncertain boundary conditions in active structural acoustic control by optimizing the placement of transducers with respect to those uncertainties.

Discussion of Electrode Conditioning Mechanism Based on Pre-breakdown Current under Non-uniform Electric Field in Vacuum

NASA Astrophysics Data System (ADS)

Yasuoka, Takanori; Kato, Tomohiro; Kato, Katsumi; Okubo, Hitoshi

Electrode conditioning is very important technique for improvement of the insulation performance of vacuum circuit breakers (VCBs). This paper discusses the spark conditioning mechanism under non-uniform electric field focused on the pre-breakdown current. We quantitatively evaluated the spark conditioning effect by analyzing the pre-breakdown current based on Fowler-Nordheim equation. As a result, field enhancement factor β decreased with the increasing in breakdown voltage in the beginning of conditioning process, and finally β was saturated with the saturation of breakdown voltage. In addition, in case of non-uniform field, we found that β on high voltage rod electrode after conditioning varied according to the electric field strength on the rod electrode.

The Statistical Signal of Morphological Process in Stratigraphy

NASA Astrophysics Data System (ADS)

Esposito, C. R.; Straub, K. M.

2013-12-01

The most widely used classification of river delta morphologies, Galloway's ternary diagram, holds that the surface characteristics of a delta, including the distribution of depositional environments, and shoreline shape, can be predicted by the relative strengths of the fluvial and marine processes that influence the delta. Though almost 40 years old, Galloway's diagram of wave, river, and tide dominated deltas is still widely referred to in textbooks and in literature as a way of describing the relationship between morphological processes and the distribution of depositional environments over a single delta 'event' such as the progradation of one delta lobe. However, there is no complimentary classification scheme that addresses the ways in which deltaic stratigraphy under varying forcing conditions is preserved over sequences of many such events. Such sequences operating over a range of time scales set the architecture of sedimentary basins, so a method of classifying the stratigraphic result is an important goal. In this study, we use Delft3D to examine the autogenic behavior of thick packages of simulated deltaic stratigraphy (>10 channel depths) under the influence of a range of wave, tide, and flood-dominated conditions, as well as a variety of sedimentary inputs. We quantify the strength and type of autogenic behavior by measuring stratigraphic completeness and compensation index. Both metrics have been observed to vary systematically in field scale systems, and in experimental deltas deposited under a range of river dominated conditions. This work will extend that range into deltas with significant wave, tide, and flood influence.

CONTROL LIMITER DEVICE

DOEpatents

DeShong, J.A.

1960-03-01

A control-limiting device for monltoring a control system is described. The system comprises a conditionsensing device, a condition-varying device exerting a control over the condition, and a control means to actuate the condition-varying device. A control-limiting device integrates the total movement or other change of the condition-varying device over any interval of time during a continuum of overlapping periods of time, and if the tothl movement or change of the condition-varying device exceeds a preset value, the control- limiting device will switch the control of the operated apparatus from automatic to manual control.

Cerebral laterality and verbal processes.

PubMed

Sherman, J L; Kulhavy, R W; Burns, K

1976-11-01

Research suggests that we process information by way of two distinct and functionallly separate coding systems. The localization of these two processing systems appears to be somewhat dependent on cerebral laterality, which has been shown to vary in right-handed and left-handed persons. To test the dual coding model, right-handed and left-handed subjects learned lists of abstract and concrete words under various conditions of visual and tactile interference. Right-handed subjects showed a significant superiority in the remembering of highly concrete items, while total recall did not differ reliably between groups.

Investigation of composition dependence of the nanowire samples grown on brass on synthesis conditions

NASA Astrophysics Data System (ADS)

Srivastava, Himanshu; Khooha, Ajay; Singh, Ajit; Ganguli, Tapas

2018-04-01

The study of the growth of nanowires on α-brass (Cu 65%, Zn 35%) substrate was done by annealing the substrates at different temperatures in air and varying flow of moist nitrogen. It was found that the surface composition of oxidized brass depended on the synthesis condition. Angle Dependent X-ray Fluorescence (ADXRF) measurements of the oxidized brass samples were done to study the variation of composition with the synthesis conditions and depth. The results showed that the cause of the compositional dependence on synthesis parameters is due to a process, inherent to the oxidation of brass.

Spectral Imaging from Uavs Under Varying Illumination Conditions

NASA Astrophysics Data System (ADS)

Hakala, T.; Honkavaara, E.; Saari, H.; Mäkynen, J.; Kaivosoja, J.; Pesonen, L.; Pölönen, I.

2013-08-01

Rapidly developing unmanned aerial vehicles (UAV) have provided the remote sensing community with a new rapidly deployable tool for small area monitoring. The progress of small payload UAVs has introduced greater demand for light weight aerial payloads. For applications requiring aerial images, a simple consumer camera provides acceptable data. For applications requiring more detailed spectral information about the surface, a new Fabry-Perot interferometer based spectral imaging technology has been developed. This new technology produces tens of successive images of the scene at different wavelength bands in very short time. These images can be assembled in spectral data cubes with stereoscopic overlaps. On field the weather conditions vary and the UAV operator often has to decide between flight in sub optimal conditions and no flight. Our objective was to investigate methods for quantitative radiometric processing of images taken under varying illumination conditions, thus expanding the range of weather conditions during which successful imaging flights can be made. A new method that is based on insitu measurement of irradiance either in UAV platform or in ground was developed. We tested the methods in a precision agriculture application using realistic data collected in difficult illumination conditions. Internal homogeneity of the original image data (average coefficient of variation in overlapping images) was 0.14-0.18. In the corrected data, the homogeneity was 0.10-0.12 with a correction based on broadband irradiance measured in UAV, 0.07-0.09 with a correction based on spectral irradiance measurement on ground, and 0.05-0.08 with a radiometric block adjustment based on image data. Our results were very promising, indicating that quantitative UAV based remote sensing could be operational in diverse conditions, which is prerequisite for many environmental remote sensing applications.

Removal of refractory organics in nanofiltration concentrates of municipal solid waste leachate treatment plants by combined Fenton oxidative-coagulation with photo--Fenton processes.

PubMed

Li, Jiuyi; Zhao, Lei; Qin, Lele; Tian, Xiujun; Wang, Aimin; Zhou, Yanmei; Meng, Liao; Chen, Yong

2016-03-01

Removal of the refractory organic matters in leachate brines generated from nanofiltration unit in two full-scale municipal solid waste landfill leachate treatment plants was investigated by Fenton oxidative-coagulation and ultraviolet photo - Fenton processes in this study. Fenton oxidative-coagulation was performed under the condition of an initial pH of 5.0 and low H2O2/Fe(2+) ratios. After precipitate separation, the remaining organic constituents were further oxidized by photo - Fenton process. For both leachate brines with varying pollution strength, more than 90% COD and TOC reductions were achieved at H2O2/Fe(2+) dosages of 35 mM/8 mM and 90 mM/10 mM, respectively. The effluent COD ranged 120-160 mg/L under the optimal operating conditions, and the biodegradability was increased significantly. Fenton oxidative-coagulation was demonstrated to contribute nearly 70% overall removal of organic matters. In the combined processes, the efficiency of hydrogen peroxide varied from 216 to 228%, which may significantly reduce the operating cost of conventional Fenton method. Six phthalic acid esters and thirteen polycyclic aromatic hydrocarbons were found in leachate brines, and, on the average, around 80% phthalic acid esters and 90% polycyclic aromatic hydrocarbons were removed by the combined treatments. Copyright © 2015 Elsevier Ltd. All rights reserved.

Risk management in spatio-temporally varying field by true slime mold

NASA Astrophysics Data System (ADS)

Ito, Kentaro; Sumpter, David; Nakagaki, Toshiyuki

Revealing how lower organisms solve complicated problems is a challenging research area, which could reveal the evolutionary origin of biological information processing. Here we report on the ability of a single-celled organism, true slime mold, to find a smart solution of risk management under spatio-temporally varying conditions. We designed test conditions under which there were three food-locations at vertices of equilateral triangle and a toxic light illuminated the organism on alternating halves of the triangle. We found that the organism behavior depended on the period of the repeated illumination, even though the total exposure time was kept the same . A simple mathematical model for the experimental results is proposed from a dynamical system point of view. We discuss our results in the context of a strategy of risk management by Physarum.

Evaluation of the pair-culture effect in Ophyryotrocha puerilis (Polychaeta: Dorvilleidae). II. Conditions for the moult of the upper jaw

NASA Astrophysics Data System (ADS)

Kegel, B.; Pfannenstiel, H.-D.

1983-06-01

The conditions for moult of the upper jaw of Ophryotrocha puerilis were determined in isolated individuals and in groups of various sizes. The frequency of formation of the complicated upper jaw in both isolated individuals and in groups varies to a considerable extent. Although formation of the upper jaw and sex reversal normally are associated processes, the relationship of these two processes is not very well understood. Histological investigations at the light microscopic level demonstrate that the dental apparatus is an elaboration of the ectodermal stomodaeum which is considered to be a highly specialized part of the cuticle in the pharyngeal region of the gut.

[Effects on phenol removal in the process of enhanced coagulation by manganese dioxide formed in situ].

PubMed

Zhang, Li-Zhu; Chen, Xiao-Dong; Ma, Jun; Yu, Min; Li, Xin

2011-10-01

Phenol was selected as a model compound. Factors, such as Ca2+, tannic acid, dose of kaolinite, dose of manganese dioxide formed in situ and pH, were invested on phenol removal in the process of enhanced coagulation by manganese dioxide formed in situ. Results showed that the addition of Ca2+ is beneficial for phenol removal. In the range of Ca2+ varied from 0 to 1.0 mmol x L(-1), the efficiency of phenol removal was enhanced more than 10%. Tannic acid can enhance phenol removal significantly when they are coexisted in water. As tannic acid was added to 10 mg x L(-1), phenol removal can be increased about 30% and 50% in the process of coagulation by AlCl3 and enhanced coagulation by manganese dioxide formed in situ, respectively. The dose of coagulant can be reduced in the process of enhanced coagulation with the addition of manganese dioxide formed in situ. The point of 1 mg x L(-1) manganese dioxide formed in situ linked with 30 mg x L(-1) AlCl3 can have the same phenol removal efficiency as the addition of 50 mg x L(-1) AlCl3. In the range of pH varied from 5 to 9, phenol can be removed with the high efficiency in the process of enhanced coagulation by manganese dioxide formed in situ. While under the strong acid condition and strong basic condition, phenol has lower removal efficiency.

Complex Dynamic Processes in Sign Tracking With an Omission Contingency (Negative Automaintenance)

PubMed Central

Killeen, Peter R.

2008-01-01

Hungry pigeons received food periodically, signaled by the onset of a keylight. Key pecks aborted the feeding. Subjects responded for thousands of trials, despite the contingent nonreinforcement, with varying probability as the intertrial interval was varied. Hazard functions showed the dominant tendency to be perseveration in responding and not responding. Once perseveration was accounted for, a linear operator model of associative conditioning further improved predictions. Response rates during trials were correlated with the prior probabilities of a response. Rescaled range analyses showed that the behavioral trajectories were a kind of fractional Brownian motion. PMID:12561133

Complex dynamic processes in sign tracking with an omission contingency (negative automaintenance).

PubMed

Killeen, Peter R

2003-01-01

Hungry pigeons received food periodically, signaled by the onset of a keylight. Key pecks aborted the feeding. Subjects responded for thousands of trials, despite the contingent nonreinforcement, with varying probability as the intertrial interval was varied. Hazard functions showed the dominant tendency to be perseveration in responding and not responding. Once perseveration was accounted for, a linear operator model of associative conditioning further improved predictions. Response rates during trials were correlated with the prior probabilities of a response. Rescaled range analyses showed that the behavioral trajectories were a kind of fractional Brownian motion.

Evaluation of Varying Ductile Fracture Criteria for 42CrMo Steel by Compressions at Different Temperatures and Strain Rates

PubMed Central

Quan, Guo-zheng; Luo, Gui-chang; Mao, An; Liang, Jian-ting; Wu, Dong-sen

2014-01-01

Fracturing by ductile damage occurs quite naturally in metal forming processes, and ductile fracture of strain-softening alloy, here 42CrMo steel, cannot be evaluated through simple procedures such as tension testing. Under these circumstances, it is very significant and economical to find a way to evaluate the ductile fracture criteria (DFC) and identify the relationships between damage evolution and deformation conditions. Under the guidance of the Cockcroft-Latham fracture criteria, an innovative approach involving hot compression tests, numerical simulations, and mathematic computations provides mutual support to evaluate ductile damage cumulating process and DFC diagram along with deformation conditions, which has not been expounded by Cockcroft and Latham. The results show that the maximum damage value appears in the region of upsetting drum, while the minimal value appears in the middle region. Furthermore, DFC of 42CrMo steel at temperature range of 1123~1348 K and strain rate of 0.01~10 s−1 are not constant but change in a range of 0.160~0.226; thus, they have been defined as varying ductile fracture criteria (VDFC) and characterized by a function of temperature and strain rate. In bulk forming operations, VDFC help technicians to choose suitable process parameters and avoid the occurrence of fracture. PMID:24592175

Distinct Soil Microbial Communities in habitats of differing soil water balance on the Tibetan Plateau

PubMed Central

Li, Yuntao; Adams, Jonathan; Shi, Yu; Wang, Hao; He, Jin-Sheng; Chu, Haiyan

2017-01-01

Global change may be a severe threat to natural and agricultural systems, partly through its effects in altering soil biota and processes, due to changes in water balance. We studied the potential influence of changing soil water balance on soil biota by comparing existing sites along a natural water balance gradient in the Qinghai-Tibetan Plateau. In this study, the community structure of bacteria, archaea and eukaryotes differed between the different soil water conditions. Soil moisture was the strongest predictor of bacterial and eukaryotic community structure, whereas C/N ratio was the key factor predicting variation in the archaeal community. Bacterial and eukaryotic diversity was quite stable among different soil water availability, but archaeal diversity was dramatically different between the habitats. The auxotype of methanogens also varied significantly among different habitats. The co-varying soil properties among habitats shaped the community structure of soil microbes, with archaea being particularly sensitive in terms of community composition, diversity and functional groups. Bacterial and archaeal phylogenetic community turnover was mainly driven by deterministic processes while stochastic processes had stronger effects on eukaryotic phylogenetic community turnover. Our work provides insight into microbial community, functional group and phylogenetic turnover under different soil conditions in low-latitude alpine ecosystem. PMID:28401921

Distinct Soil Microbial Communities in habitats of differing soil water balance on the Tibetan Plateau

NASA Astrophysics Data System (ADS)

Li, Yuntao; Adams, Jonathan; Shi, Yu; Wang, Hao; He, Jin-Sheng; Chu, Haiyan

2017-04-01

Global change may be a severe threat to natural and agricultural systems, partly through its effects in altering soil biota and processes, due to changes in water balance. We studied the potential influence of changing soil water balance on soil biota by comparing existing sites along a natural water balance gradient in the Qinghai-Tibetan Plateau. In this study, the community structure of bacteria, archaea and eukaryotes differed between the different soil water conditions. Soil moisture was the strongest predictor of bacterial and eukaryotic community structure, whereas C/N ratio was the key factor predicting variation in the archaeal community. Bacterial and eukaryotic diversity was quite stable among different soil water availability, but archaeal diversity was dramatically different between the habitats. The auxotype of methanogens also varied significantly among different habitats. The co-varying soil properties among habitats shaped the community structure of soil microbes, with archaea being particularly sensitive in terms of community composition, diversity and functional groups. Bacterial and archaeal phylogenetic community turnover was mainly driven by deterministic processes while stochastic processes had stronger effects on eukaryotic phylogenetic community turnover. Our work provides insight into microbial community, functional group and phylogenetic turnover under different soil conditions in low-latitude alpine ecosystem.

Evaluation of varying ductile fracture criteria for 42CrMo steel by compressions at different temperatures and strain rates.

PubMed

Quan, Guo-zheng; Luo, Gui-chang; Mao, An; Liang, Jian-ting; Wu, Dong-sen

2014-01-01

Fracturing by ductile damage occurs quite naturally in metal forming processes, and ductile fracture of strain-softening alloy, here 42CrMo steel, cannot be evaluated through simple procedures such as tension testing. Under these circumstances, it is very significant and economical to find a way to evaluate the ductile fracture criteria (DFC) and identify the relationships between damage evolution and deformation conditions. Under the guidance of the Cockcroft-Latham fracture criteria, an innovative approach involving hot compression tests, numerical simulations, and mathematic computations provides mutual support to evaluate ductile damage cumulating process and DFC diagram along with deformation conditions, which has not been expounded by Cockcroft and Latham. The results show that the maximum damage value appears in the region of upsetting drum, while the minimal value appears in the middle region. Furthermore, DFC of 42CrMo steel at temperature range of 1123~1348 K and strain rate of 0.01~10 s(-1) are not constant but change in a range of 0.160~0.226; thus, they have been defined as varying ductile fracture criteria (VDFC) and characterized by a function of temperature and strain rate. In bulk forming operations, VDFC help technicians to choose suitable process parameters and avoid the occurrence of fracture.

Identification of Time-Varying Pilot Control Behavior in Multi-Axis Control Tasks

NASA Technical Reports Server (NTRS)

Zaal, Peter M. T.; Sweet, Barbara T.

2012-01-01

Recent developments in fly-by-wire control architectures for rotorcraft have introduced new interest in the identification of time-varying pilot control behavior in multi-axis control tasks. In this paper a maximum likelihood estimation method is used to estimate the parameters of a pilot model with time-dependent sigmoid functions to characterize time-varying human control behavior. An experiment was performed by 9 general aviation pilots who had to perform a simultaneous roll and pitch control task with time-varying aircraft dynamics. In 8 different conditions, the axis containing the time-varying dynamics and the growth factor of the dynamics were varied, allowing for an analysis of the performance of the estimation method when estimating time-dependent parameter functions. In addition, a detailed analysis of pilots adaptation to the time-varying aircraft dynamics in both the roll and pitch axes could be performed. Pilot control behavior in both axes was significantly affected by the time-varying aircraft dynamics in roll and pitch, and by the growth factor. The main effect was found in the axis that contained the time-varying dynamics. However, pilot control behavior also changed over time in the axis not containing the time-varying aircraft dynamics. This indicates that some cross coupling exists in the perception and control processes between the roll and pitch axes.

Cooling Rate Determination in Additively Manufactured Aluminum Alloy 2219

NASA Astrophysics Data System (ADS)

Brice, Craig A.; Dennis, Noah

2015-05-01

Metallic additive manufacturing processes generally utilize a conduction mode, welding-type approach to create beads of deposited material that can be arranged into a three-dimensional structure. As with welding, the cooling rates in the molten pool are relatively rapid compared to traditional casting techniques. Determination of the cooling rate in the molten pool is critical for predicting the solidified microstructure and resultant properties. In this experiment, wire-fed electron beam additive manufacturing was used to melt aluminum alloy 2219 under different thermal boundary conditions. The dendrite arm spacing was measured in the remelted material, and this information was used to estimate cooling rates in the molten pool based on established empirical relationships. The results showed that the thermal boundary conditions have a significant effect on the resulting cooling rate in the molten pool. When thermal conduction is limited due to a small thermal sink, the dendrite arm spacing varies between 15 and 35 µm. When thermal conduction is active, the dendrite arm spacing varies between 6 and 12 µm. This range of dendrite arm spacing implies cooling rates ranging from 5 to 350 K/s. Cooling rates can vary greatly as thermal conditions change during deposition. A cooling rate at the higher end of the range could lead to significant deviation from microstructural equilibrium during solidification.

Understanding scale dependency of climatic processes with diarrheal disease

NASA Astrophysics Data System (ADS)

Nasr Azadani, F.; Jutla, A.; Akanda, A. S. S.; Colwell, R. R.

2015-12-01

The issue of scales in linking climatic processes with diarrheal diseases is perhaps one of the most challenging aspect to develop any predictive algorithm for outbreaks and to understand impacts of changing climate. Majority of diarrheal diseases have shown to be strongly associated with climate modulated environmental processes where pathogens survive. Using cholera as an example of characteristic diarrheal diseases, this study will provide methodological insights on dominant scale variability in climatic processes that are linked with trigger and transmission of disease. Cholera based epidemiological models use human to human interaction as a main transmission mechanism, however, environmental conditions for creating seasonality in outbreaks is not explicitly modeled. For example, existing models cannot create seasonality, unless some of the model parameters are a-priori chosen to vary seasonally. A systems based feedback approach will be presented to understand role of climatic processes on trigger and transmission disease. In order to investigate effect of changing climate on cholera, a downscaling approach using support vector machine will be used. Our preliminary results using three climate models, ECHAM5, GFDL, and HADCM show that varying modalities in future cholera outbreaks.

Investigation of aerosol indirect effects on simulated flash-flood heavy rainfall over Korea

NASA Astrophysics Data System (ADS)

Lim, Kyo-Sun Sunny; Hong, Song-You

2012-11-01

This study investigates aerosol indirect effects on the development of heavy rainfall near Seoul, South Korea, on 12 July 2006, focusing on precipitation amount. The impact of the aerosol concentration on simulated precipitation is evaluated by varying the initial cloud condensation nuclei (CCN) number concentration in the Weather Research and Forecasting (WRF) Double-Moment 6-class (WDM6) microphysics scheme. The simulations are performed under clean, semi-polluted, and polluted conditions. Detailed analysis of the physical processes that are responsible for surface precipitation, including moisture and cloud microphysical budgets shows enhanced ice-phase processes to be the primary driver of increased surface precipitation under the semi-polluted condition. Under the polluted condition, suppressed auto-conversion and the enhanced evaporation of rain cause surface precipitation to decrease. To investigate the role of environmental conditions on precipitation response under different aerosol number concentrations, a set of sensitivity experiments are conducted with a 5 % decrease in relative humidity at the initial time, relative to the base simulations. Results show ice-phase processes having small sensitivity to CCN number concentration, compared with the base simulations. Surface precipitation responds differently to CCN number concentration under the lower humidity initial condition, being greatest under the clean condition, followed by the semi-polluted and polluted conditions.

Toward intensifying design of experiments in upstream bioprocess development: An industrial Escherichia coli feasibility study.

PubMed

von Stosch, Moritz; Hamelink, Jan-Martijn; Oliveira, Rui

2016-09-01

In this study, step variations in temperature, pH, and carbon substrate feeding rate were performed within five high cell density Escherichia coli fermentations to assess whether intraexperiment step changes, can principally be used to exploit the process operation space in a design of experiment manner. A dynamic process modeling approach was adopted to determine parameter interactions. A bioreactor model was integrated with an artificial neural network that describes biomass and product formation rates as function of varied fed-batch fermentation conditions for heterologous protein production. A model reliability measure was introduced to assess in which process region the model can be expected to predict process states accurately. It was found that the model could accurately predict process states of multiple fermentations performed at fixed conditions within the determined validity domain. The results suggest that intraexperimental variations of process conditions could be used to reduce the number of experiments by a factor, which in limit would be equivalent to the number of intraexperimental variations per experiment. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1343-1352, 2016. © 2016 American Institute of Chemical Engineers.

Biochar Preparation from Simulated Municipal Solid Waste Employing Low Temperature Carbonization Process

NASA Astrophysics Data System (ADS)

Areeprasert, C.; Leelachaikul, P.; Jangkobpattana, G.; Phumprasop, K.; Kiattiwat, T.

2018-02-01

This paper presents an investigation on carbonization process of simulated municipal solid waste (MSW). Simulated MSW consists of a representative of food residue (68%), plastic waste (20%), paper (8%), and textile (4%). Laboratory-scale carbonization was performed in this study using a vertical-type pyrolyzer varying carbonization temperature (300, 350, 400, and 450 °C) and heating rate (5, 10, 15, and 20 °C/min). Appearance of the biochar product was in black and the volume was significantly reduced. Low carbonization temperature (300 °C) might not completely decompose plastic materials in MSW. Results showed that the carbonization at the temperature of 400 °C with the heating rate of 5 °C/min was the optimal condition. The yield of biochar from the optimal process was 50.6% with the heating value of 26.85 MJ/kg. Energy input of the process was attributed to water evaporation and the decomposition of plastics and paper. Energy output of the process was highest at the optimal condition. Energy output and input ratio was around 1.3-1.7 showing the feasibility of the carbonization process in all heating rate condition.

Yeast population dynamics of industrial fuel-ethanol fermentation process assessed by PCR-fingerprinting.

PubMed

da Silva-Filho, Eurípedes Alves; Brito dos Santos, Scheila Karina; Resende, Alecsandra do Monte; de Morais, José Otamar Falcão; de Morais, Marcos Antonio; Ardaillon Simões, Diogo

2005-07-01

Yeast population used in industrial production of fuel-ethanol may vary according to the plant process condition and to the environmental stresses imposed to yeast cells. Therefore, yeast strains isolated from a particular industrial process may be adapted to such conditions and should be used as starter strain instead of less adapted commercial strains. This work reports the use of PCR-fingerprinting method based on microsatellite primer (GTG)5 to characterize the yeast population dynamics along the fermentation period in six distilleries. The results show that indigenous fermenting strains present in the crude substrate can be more adapted to the industrial process than commercial strains. We also identified new strains that dominate the yeast population and were more present either in molasses or sugar cane fermenting distilleries. Those strains were proposed to be used as starters in those industrial processes. This is the first report on the use of molecular markers to discriminate Saccharomyces cerevisiae strains from fuel-ethanol producing process.

Estimation and Application of Ecological Memory Functions in Time and Space

NASA Astrophysics Data System (ADS)

Itter, M.; Finley, A. O.; Dawson, A.

2017-12-01

A common goal in quantitative ecology is the estimation or prediction of ecological processes as a function of explanatory variables (or covariates). Frequently, the ecological process of interest and associated covariates vary in time, space, or both. Theory indicates many ecological processes exhibit memory to local, past conditions. Despite such theoretical understanding, few methods exist to integrate observations from the recent past or within a local neighborhood as drivers of these processes. We build upon recent methodological advances in ecology and spatial statistics to develop a Bayesian hierarchical framework to estimate so-called ecological memory functions; that is, weight-generating functions that specify the relative importance of local, past covariate observations to ecological processes. Memory functions are estimated using a set of basis functions in time and/or space, allowing for flexible ecological memory based on a reduced set of parameters. Ecological memory functions are entirely data driven under the Bayesian hierarchical framework—no a priori assumptions are made regarding functional forms. Memory function uncertainty follows directly from posterior distributions for model parameters allowing for tractable propagation of error to predictions of ecological processes. We apply the model framework to simulated spatio-temporal datasets generated using memory functions of varying complexity. The framework is also applied to estimate the ecological memory of annual boreal forest growth to local, past water availability. Consistent with ecological understanding of boreal forest growth dynamics, memory to past water availability peaks in the year previous to growth and slowly decays to zero in five to eight years. The Bayesian hierarchical framework has applicability to a broad range of ecosystems and processes allowing for increased understanding of ecosystem responses to local and past conditions and improved prediction of ecological processes.

A generalized conditional heteroscedastic model for temperature downscaling

NASA Astrophysics Data System (ADS)

Modarres, R.; Ouarda, T. B. M. J.

2014-11-01

This study describes a method for deriving the time varying second order moment, or heteroscedasticity, of local daily temperature and its association to large Coupled Canadian General Circulation Models predictors. This is carried out by applying a multivariate generalized autoregressive conditional heteroscedasticity (MGARCH) approach to construct the conditional variance-covariance structure between General Circulation Models (GCMs) predictors and maximum and minimum temperature time series during 1980-2000. Two MGARCH specifications namely diagonal VECH and dynamic conditional correlation (DCC) are applied and 25 GCM predictors were selected for a bivariate temperature heteroscedastic modeling. It is observed that the conditional covariance between predictors and temperature is not very strong and mostly depends on the interaction between the random process governing temporal variation of predictors and predictants. The DCC model reveals a time varying conditional correlation between GCM predictors and temperature time series. No remarkable increasing or decreasing change is observed for correlation coefficients between GCM predictors and observed temperature during 1980-2000 while weak winter-summer seasonality is clear for both conditional covariance and correlation. Furthermore, the stationarity and nonlinearity Kwiatkowski-Phillips-Schmidt-Shin (KPSS) and Brock-Dechert-Scheinkman (BDS) tests showed that GCM predictors, temperature and their conditional correlation time series are nonlinear but stationary during 1980-2000 according to BDS and KPSS test results. However, the degree of nonlinearity of temperature time series is higher than most of the GCM predictors.

Kinetic Monte Carlo simulation of dopant-defect systems under submicrosecond laser thermal processes

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

Fisicaro, G.; Pelaz, Lourdes; Lopez, P.

2012-11-06

An innovative Kinetic Monte Carlo (KMC) code has been developed, which rules the post-implant kinetics of the defects system in the extremely far-from-the equilibrium conditions caused by the laser irradiation close to the liquid-solid interface. It considers defect diffusion, annihilation and clustering. The code properly implements, consistently to the stochastic formalism, the fast varying local event rates related to the thermal field T(r,t) evolution. This feature of our numerical method represents an important advancement with respect to current state of the art KMC codes. The reduction of the implantation damage and its reorganization in defect aggregates are studied as amore » function of the process conditions. Phosphorus activation efficiency, experimentally determined in similar conditions, has been related to the emerging damage scenario.« less

Characterisation and treatment of VOCs in process water from upgrading facilities for compressed biogas (CBG).

PubMed

Nilsson Påledal, S; Arrhenius, K; Moestedt, J; Engelbrektsson, J; Stensen, K

2016-02-01

Compression and upgrading of biogas to vehicle fuel generates process water, which to varying degrees contains volatile organic compounds (VOCs) originating from the biogas. The compostion of this process water has not yet been studied and scientifically published and there is currently an uncertainty regarding content of VOCs and how the process water should be managed to minimise the impact on health and the environment. The aim of the study was to give an overview about general levels of VOCs in the process water. Characterisation of process water from amine and water scrubbers at plants digesting waste, sewage sludge or agricultural residues showed that both the average concentration and composition of particular VOCs varied depending on the substrate used at the biogas plant, but the divergence was high and the differences for total concentrations from the different substrate groups were only significant for samples from plants using waste compared to residues from agriculture. The characterisation also showed that the content of VOCs varied greatly between different sampling points for same main substrate and between sampling occasions at the same sampling point, indicating that site-specific conditions are important for the results which also indicates that a number of analyses at different times are required in order to make an more exact characterisation with low uncertainty. Inhibition of VOCs in the anaerobic digestion (AD) process was studied in biomethane potential tests, but no inhibition was observed during addition of synthetic process water at concentrations of 11.6 mg and 238 mg VOC/L. Copyright © 2015 Elsevier Ltd. All rights reserved.

Multivariate statistical process control (MSPC) using Raman spectroscopy for in-line culture cell monitoring considering time-varying batches synchronized with correlation optimized warping (COW).

PubMed

Liu, Ya-Juan; André, Silvère; Saint Cristau, Lydia; Lagresle, Sylvain; Hannas, Zahia; Calvosa, Éric; Devos, Olivier; Duponchel, Ludovic

2017-02-01

Multivariate statistical process control (MSPC) is increasingly popular as the challenge provided by large multivariate datasets from analytical instruments such as Raman spectroscopy for the monitoring of complex cell cultures in the biopharmaceutical industry. However, Raman spectroscopy for in-line monitoring often produces unsynchronized data sets, resulting in time-varying batches. Moreover, unsynchronized data sets are common for cell culture monitoring because spectroscopic measurements are generally recorded in an alternate way, with more than one optical probe parallelly connecting to the same spectrometer. Synchronized batches are prerequisite for the application of multivariate analysis such as multi-way principal component analysis (MPCA) for the MSPC monitoring. Correlation optimized warping (COW) is a popular method for data alignment with satisfactory performance; however, it has never been applied to synchronize acquisition time of spectroscopic datasets in MSPC application before. In this paper we propose, for the first time, to use the method of COW to synchronize batches with varying durations analyzed with Raman spectroscopy. In a second step, we developed MPCA models at different time intervals based on the normal operation condition (NOC) batches synchronized by COW. New batches are finally projected considering the corresponding MPCA model. We monitored the evolution of the batches using two multivariate control charts based on Hotelling's T 2 and Q. As illustrated with results, the MSPC model was able to identify abnormal operation condition including contaminated batches which is of prime importance in cell culture monitoring We proved that Raman-based MSPC monitoring can be used to diagnose batches deviating from the normal condition, with higher efficacy than traditional diagnosis, which would save time and money in the biopharmaceutical industry. Copyright © 2016 Elsevier B.V. All rights reserved.

Inter- and Intra-Specific Differences in Foliar N Concentrations of Juvenile Loblolly and Slash Pine in North Florida

Treesearch

Yu Xiao; Eric J. Jokela; Tim L. White; Dudley A. Huber

2002-01-01

Differences in foliar N concentrations among species, families, and clones may contribute to variation in relative growth performance under varying environmental conditions. Only limited information exists regarding the importance of genetic vs. environmental controls on the nutritional characteristics of loblolly and slash pine. Knowledge of these processes may...

Intervening with Care--Varying Outcomes of a Training and Development Programme in Elderly Care in Sweden

ERIC Educational Resources Information Center

Hauer, Esther; Westerberg, Kristina; Nordlund, Annika M.

2017-01-01

Awareness of the mechanisms underlying training and development (T&D) programmes is crucial in creating sustainable learning conditions in organisations. The organisational and psychosocial aspects of the work environment in Swedish elderly care is the focus of this longitudinal study, and the relation between process and results of a T&D…

Evaluation of forest snow processes models (SnowMKIP2)

Treesearch

Nick Rutter; Richard Essery; John Pomeroy; Nuria Altimir; Kostas Andreadis; Ian Baker; Alan Barr; Paul Bartlett; Aaron Boone; Huiping Deng; Herve Douville; Emanuel Dutra; Kelly Elder; others

2009-01-01

Thirty-three snowpack models of varying complexity and purpose were evaluated across a wide range of hydrometeorological and forest canopy conditions at five Northern Hemisphere locations, for up to two winter snow seasons. Modeled estimates of snow water equivalent (SWE) or depth were compared to observations at forest and open sites at each location. Precipitation...

Orientation and Affective Expression Effects on Face Recognition in Williams Syndrome and Autism

ERIC Educational Resources Information Center

Rose, Fredric E.; Lincoln, Alan J.; Lai, Zona; Ene, Michaela; Searcy, Yvonne M.; Bellugi, Ursula

2007-01-01

We sought to clarify the nature of the face processing strength commonly observed in individuals with Williams syndrome (WS) by comparing the face recognition ability of persons with WS to that of persons with autism and to healthy controls under three conditions: Upright faces with neutral expressions, upright faces with varying affective…

The Organization of Exploratory Behaviors in Infant Locomotor Planning

ERIC Educational Resources Information Center

Kretch, Kari S.; Adolph, Karen E.

2017-01-01

How do infants plan and guide locomotion under challenging conditions? This experiment investigated the real-time process of visual and haptic exploration in 14-month-old infants as they decided whether and how to walk over challenging terrain--a series of bridges varying in width. Infants' direction of gaze was recorded with a head-mounted eye…

Force characteristics in continuous path controlled crankpin grinding

NASA Astrophysics Data System (ADS)

Zhang, Manchao; Yao, Zhenqiang

2015-03-01

Recent research on the grinding force involved in cylindrical plunge grinding has focused mainly on steady-state conditions. Unlike in conventional external cylindrical plunge grinding, the conditions between the grinding wheel and the crankpin change periodically in path controlled grinding because of the eccentricity of the crankpin and the constant rotational speed of the crankshaft. The objective of this study is to investigate the effects of various grinding conditions on the characteristics of the grinding force during continuous path controlled grinding. Path controlled plunge grinding is conducted at a constant rotational speed using a cubic boron nitride (CBN) wheel. The grinding force is determined by measuring the torque. The experimental results show that the force and torque vary sinusoidally during dry grinding and load grinding. The variations in the results reveal that the resultant grinding force and torque decrease with higher grinding speeds and increase with higher peripheral speeds of the pin and higher grinding depths. In path controlled grinding, unlike in conventional external cylindrical plunge grinding, the axial grinding force cannot be disregarded. The speeds and speed ratios of the workpiece and wheel are also analyzed, and the analysis results show that up-grinding and down-grinding occur during the grinding process. This paper proposes a method for describing the force behavior under varied process conditions during continuous path controlled grinding, which provides a beneficial reference for describing the material removal mechanism and for optimizing continuous controlled crankpin grinding.

Self-awareness and the subconscious effect of personal pronouns on word encoding: a magnetoencephalography (MEG) study.

PubMed

Walla, Peter; Greiner, Katharina; Duregger, Cornelia; Deecke, Lüder; Thurner, Stefan

2007-03-02

The effect of personal pronouns such as "ein" (German for "a"), "mein" (German for "my") and "sein" (German for "his") on the processing of associated nouns was investigated using MEG. Three different encoding strategies were provided in order to vary the level of consciousness involved in verbal information processing. A shallow (alphabetic), a deep (semantic) and a very deep (contextual) encoding instruction related to visual word presentation were given to all study participants. After the encoding of pronoun-noun pairs, recognition performances of nouns only were tested. The number of correctly recognized nouns previously associated with "sein" was significantly lower than the number of correctly recognized nouns previously associated with "ein" in the shallow encoding condition. The same trend was found for "mein" associated nouns which were also less accurately recognized compared to "ein" associated nouns. Magnetic field distributions recorded during the encoding phases revealed two significant effects, one between about 200 and 400ms after stimulus onset and the other between about 500 and 800ms. The earlier effect was found over occipito-parietal sensors, whereas the later effect occurred over left frontal sensors. Within both time ranges, brain activation varied significantly as a function of associated pronoun independent of depth of word processing. In the respective areas of both time ranges, conditions including personal pronouns ("mein" and "sein") showed higher magnetic field components compared to the control condition of no personal pronouns ("ein"). Evidence is shown that early stage processing is able to distinguish between no personal and personal information, whereas later stage processing is able to distinguish between information related to oneself and to another person (self and non-self). Along with other previous reports our MEG findings support the notion that particular human brain functions involved in processing neurophysiological correlates of self and non-self can be identified.

Theoretical bases for conducting certain technological processes in space

NASA Technical Reports Server (NTRS)

Okhotin, A. S.

1979-01-01

Dimensionless conservation equations are presented and the theoretical bases of fluid behavior aboard orbiting satellites with application to the processes of manufacturing crystals in weightlessness. The small amount of gravitational acceleration is shown to increase the separation of bands of varying concentration. Natural convection is shown to have no practical effect on crystallization from a liquid melt. Barodiffusion is also negligibly small in realistic conditions of weightlessness. The effects of surface tension become increasingly large, and suggestions are made for further research.

Ultra-Long Time Dynamics of Contaminant Plume Mixing Induced by Transient Forcing Factors in Geologic Formations

NASA Astrophysics Data System (ADS)

Rajabi, F.; Battiato, I.

2016-12-01

Long term predictions of the impact of anthropogenic stressors on the environment is essential to reduce the risks associated with processes such as CO2 sequestration and nuclear waste storage in the subsurface. On the other hand, transient forcing factors (e.g. time-varying injection or pumping rate) with evolving heterogeneity of time scales spanning from days to years can influence transport phenomena at the pore scale. A comprehensive spatio-temporal prediction of reactive transport in porous media under time-dependent forcing factors for thousands of years requires the formulation of continuum scale models for time-averages. Yet, as every macroscopic model, time-averaged models can loose predictivity and accuracy when certain conditions are violated. This is true whenever lack of temporal and spatial scale separation occurs and it makes the continuum scale equation a poor assumption for the processes at the pore scale. In this work, we consider mass transport of a dissolved species undergoing a heterogeneous reaction and subject to time-varying boundary conditions in a periodic porous medium. By means of homogenization method and asymptotic expansion technique, we derive a macro-time continuum-scale equation as well as expressions for its effective properties. Our analysis demonstrates that the dynamics at the macro-scale is strongly influenced by the interplay between signal frequency at the boundary and transport processes at the pore level. In addition, we provide the conditions under which the space-time averaged equations accurately describe pore-scale processes. To validate our theoretical predictions, we consider a thin fracture with reacting walls and transient boundary conditions at the inlet. Our analysis shows a good agreement between numerical simulations and theoretical predictions. Furthermore, our numerical experiments show that mixing patterns of the contaminant plumes at the pore level strongly depend on the signal frequency.

Design-for-manufacture of gradient-index optical systems using time-varying boundary condition diffusion

NASA Astrophysics Data System (ADS)

Harkrider, Curtis Jason

2000-08-01

The incorporation of gradient-index (GRIN) material into optical systems offers novel and practical solutions to lens design problems. However, widespread use of gradient-index optics has been limited by poor correlation between gradient-index designs and the refractive index profiles produced by ion exchange between glass and molten salt. Previously, a design-for- manufacture model was introduced that connected the design and fabrication processes through use of diffusion modeling linked with lens design software. This project extends the design-for-manufacture model into a time- varying boundary condition (TVBC) diffusion model. TVBC incorporates the time-dependent phenomenon of melt poisoning and introduces a new index profile control method, multiple-step diffusion. The ions displaced from the glass during the ion exchange fabrication process can reduce the total change in refractive index (Δn). Chemical equilibrium is used to model this melt poisoning process. Equilibrium experiments are performed in a titania silicate glass and chemically analyzed. The equilibrium model is fit to ion concentration data that is used to calculate ion exchange boundary conditions. The boundary conditions are changed purposely to control the refractive index profile in multiple-step TVBC diffusion. The glass sample is alternated between ion exchange with a molten salt bath and annealing. The time of each diffusion step can be used to exert control on the index profile. The TVBC computer model is experimentally verified and incorporated into the design- for-manufacture subroutine that runs in lens design software. The TVBC design-for-manufacture model is useful for fabrication-based tolerance analysis of gradient-index lenses and for the design of manufactureable GRIN lenses. Several optical elements are designed and fabricated using multiple-step diffusion, verifying the accuracy of the model. The strength of multiple-step diffusion process lies in its versatility. An axicon, imaging lens, and curved radial lens, all with different index profile requirements, are designed out of a single glass composition.

Self-visualization of transparent microscopic objects in optical glasses under the conditions of the thermal self-action of an illuminating laser beam

NASA Astrophysics Data System (ADS)

Bubis, E. L.; Palashov, O. V.; Kuz'min, I. V.; Snetkov, I. L.; Gusev, S. A.

2017-03-01

We demonstrate the process of adaptive self-visualization of small-scale transparent objects and structures in weakly absorbing optical glasses (a glass plate made of K8 and an NS-1 neutral density filter) placed in the Fourier plane of the optical system under the conditions of thermal self-action of the illuminating laser beam. The process is based on the ideology of the classical Zernike phase contrast method. The process is implemented at the level of power of radiation of the illuminated object varying from several milliwatts to tens of watts in the visible and IR spectral ranges. The conducted experiments indicate that the visualization takes place in all glasses and optical elements fabricated from them at an appropriate level of the radiation power.

Generating survival times to simulate Cox proportional hazards models with time-varying covariates.

PubMed

Austin, Peter C

2012-12-20

Simulations and Monte Carlo methods serve an important role in modern statistical research. They allow for an examination of the performance of statistical procedures in settings in which analytic and mathematical derivations may not be feasible. A key element in any statistical simulation is the existence of an appropriate data-generating process: one must be able to simulate data from a specified statistical model. We describe data-generating processes for the Cox proportional hazards model with time-varying covariates when event times follow an exponential, Weibull, or Gompertz distribution. We consider three types of time-varying covariates: first, a dichotomous time-varying covariate that can change at most once from untreated to treated (e.g., organ transplant); second, a continuous time-varying covariate such as cumulative exposure at a constant dose to radiation or to a pharmaceutical agent used for a chronic condition; third, a dichotomous time-varying covariate with a subject being able to move repeatedly between treatment states (e.g., current compliance or use of a medication). In each setting, we derive closed-form expressions that allow one to simulate survival times so that survival times are related to a vector of fixed or time-invariant covariates and to a single time-varying covariate. We illustrate the utility of our closed-form expressions for simulating event times by using Monte Carlo simulations to estimate the statistical power to detect as statistically significant the effect of different types of binary time-varying covariates. This is compared with the statistical power to detect as statistically significant a binary time-invariant covariate. Copyright © 2012 John Wiley & Sons, Ltd.

On-Line Modal State Monitoring of Slowly Time-Varying Structures

NASA Technical Reports Server (NTRS)

Johnson, Erik A.; Bergman, Lawrence A.; Voulgaris, Petros G.

1997-01-01

Monitoring the dynamic response of structures is often performed for a variety of reasons. These reasons include condition-based maintenance, health monitoring, performance improvements, and control. In many cases the data analysis that is performed is part of a repetitive decision-making process, and in these cases the development of effective on-line monitoring schemes help to speed the decision-making process and reduce the risk of erroneous decisions. This report investigates the use of spatial modal filters for tracking the dynamics of slowly time-varying linear structures. The report includes an overview of modal filter theory followed by an overview of several structural system identification methods. Included in this discussion and comparison are H-infinity, eigensystem realization, and several time-domain least squares approaches. Finally, a two-stage adaptive on-line monitoring scheme is developed and evaluated.

Different involvement of medial prefrontal cortex and dorso-lateral striatum in automatic and controlled processing of a future conditioned stimulus.

PubMed

Pérez-Díaz, Francisco; Díaz, Estrella; Sánchez, Natividad; Vargas, Juan Pedro; Pearce, John M; López, Juan Carlos

2017-01-01

Recent studies support the idea that stimulus processing in latent inhibition can vary during the course of preexposure. Controlled attentional mechanisms are said to be important in the early stages of preexposure, while in later stages animals adopt automatic processing of the stimulus to be used for conditioning. Given this distinction, it is possible that both types of processing are governed by different neural systems, affecting differentially the retrieval of information about the stimulus. In the present study we tested if a lesion to the dorso-lateral striatum or to the medial prefrontal cortex has a selective effect on exposure to the future conditioned stimulus (CS). With this aim, animals received different amounts of exposure to the future CS. The results showed that a lesion to the medial prefrontal cortex enhanced latent inhibition in animals receiving limited preexposure to the CS, but had no effect in animals receiving extended preexposure to the CS. The lesion of the dorso-lateral striatum produced a decrease in latent inhibition, but only in animals with an extended exposure to the future conditioned stimulus. These results suggest that the dorsal striatum and medial prefrontal cortex play essential roles in controlled and automatic processes. Automatic attentional processes appear to be impaired by a lesion to the dorso-lateral striatum and facilitated by a lesion to the prefrontal cortex.

Standardization of domestic frying processes by an engineering approach.

PubMed

Franke, K; Strijowski, U

2011-05-01

An approach was developed to enable a better standardization of domestic frying of potato products. For this purpose, 5 domestic fryers differing in heating power and oil capacity were used. A very defined frying process using a highly standardized model product and a broad range of frying conditions was carried out in these fryers and the development of browning representing an important quality parameter was measured. Product-to-oil ratio, oil temperature, and frying time were varied. Quite different color changes were measured in the different fryers although the same frying process parameters were applied. The specific energy consumption for water evaporation (spECWE) during frying related to product amount was determined for all frying processes to define an engineering parameter for characterizing the frying process. A quasi-linear regression approach was applied to calculate this parameter from frying process settings and fryer properties. The high significance of the regression coefficients and a coefficient of determination close to unity confirmed the suitability of this approach. Based on this regression equation, curves for standard frying conditions (SFC curves) were calculated which describe the frying conditions required to obtain the same level of spECWE in the different domestic fryers. Comparison of browning results from the different fryers operated at conditions near the SFC curves confirmed the applicability of the approach. © 2011 Institute of Food Technologists®

Healthcare priority setting in Kenya: a gap analysis applying the accountability for reasonableness framework.

PubMed

Bukachi, Salome A; Onyango-Ouma, Washington; Siso, Jared Maaka; Nyamongo, Isaac K; Mutai, Joseph K; Hurtig, Anna Karin; Olsen, Oystein Evjen; Byskov, Jens

2014-01-01

In resource-poor settings, the accountability for reasonableness (A4R) has been identified as an important advance in priority setting that helps to operationalize fair priority setting in specific contexts. The four conditions of A4R are backed by theory, not evidence, that conformance with them improves the priority setting decisions. This paper describes the healthcare priority setting processes in Malindi district, Kenya, prior to the implementation of A4R in 2008 and evaluates the process for its conformance with the conditions for A4R. In-depth interviews and focus group discussions with key players in the Malindi district health system and a review of key policy documents and national guidelines show that the priority setting process in the district relies heavily on guidelines from the national level, making it more of a vertical, top-down orientation. Multilateral and donor agencies, national government, budgetary requirements, traditions and local culture influence the process. The four conditions of A4R are present within the priority setting process, albeit to varying degrees and referred to by different terms. There exists an opportunity for A4R to provide a guiding approach within which its four conditions can be strengthened and assessed to establish whether conformance helps improve on the priority setting process. Copyright © 2013 John Wiley & Sons, Ltd.

Different involvement of medial prefrontal cortex and dorso-lateral striatum in automatic and controlled processing of a future conditioned stimulus

PubMed Central

Pérez-Díaz, Francisco; Díaz, Estrella; Sánchez, Natividad; Vargas, Juan Pedro; Pearce, John M.

2017-01-01

Recent studies support the idea that stimulus processing in latent inhibition can vary during the course of preexposure. Controlled attentional mechanisms are said to be important in the early stages of preexposure, while in later stages animals adopt automatic processing of the stimulus to be used for conditioning. Given this distinction, it is possible that both types of processing are governed by different neural systems, affecting differentially the retrieval of information about the stimulus. In the present study we tested if a lesion to the dorso-lateral striatum or to the medial prefrontal cortex has a selective effect on exposure to the future conditioned stimulus (CS). With this aim, animals received different amounts of exposure to the future CS. The results showed that a lesion to the medial prefrontal cortex enhanced latent inhibition in animals receiving limited preexposure to the CS, but had no effect in animals receiving extended preexposure to the CS. The lesion of the dorso-lateral striatum produced a decrease in latent inhibition, but only in animals with an extended exposure to the future conditioned stimulus. These results suggest that the dorsal striatum and medial prefrontal cortex play essential roles in controlled and automatic processes. Automatic attentional processes appear to be impaired by a lesion to the dorso-lateral striatum and facilitated by a lesion to the prefrontal cortex. PMID:29240804

Real-Time Dynamic Observation of Micro-Friction on the Contact Interface of Friction Lining

PubMed Central

Zhang, Dekun; Chen, Kai; Guo, Yongbo

2018-01-01

This paper aims to investigate the microscopic friction mechanism based on in situ microscopic observation in order to record the deformation and contact situation of friction lining during the frictional process. The results show that friction coefficient increased with the shear deformation and energy loss of the surfacee, respectively. Furthermore, the friction mechanism mainly included adhesive friction in the high-pressure and high-speed conditions, whereas hysteresis friction was in the low-pressure and low-speed conditions. The mixed-friction mechanism was in the period when the working conditions varied from high pressure and speed to low pressure and speed. PMID:29498677

Force, Torque and Stiffness: Interactions in Perceptual Discrimination

PubMed Central

Wu, Bing; Klatzky, Roberta L.; Hollis, Ralph L.

2011-01-01

Three experiments investigated whether force and torque cues interact in haptic discrimination of force, torque and stiffness, and if so, how. The statistical relation between force and torque was manipulated across four experimental conditions: Either one type of cue varied while the other was constant, or both varied so as to be positively correlated, negatively correlated, or uncorrelated. Experiment 1 showed that the subjects’ ability to discriminate force was improved by positively correlated torque but impaired with uncorrelated torque, as compared to the constant torque condition. Corresponding effects were found in Experiment 2 for the influence of force on torque discrimination. These findings indicate that force and torque are integrated in perception, rather than being processed as separate dimensions. A further experiment demonstrated facilitation of stiffness discrimination by correlated force and torque, whether the correlation was positive or negative. The findings suggest new means of augmenting haptic feedback to facilitate perception of the properties of soft objects. PMID:21359137

Applying a Family Resilience Framework in Training, Practice, and Research: Mastering the Art of the Possible.

PubMed

Walsh, Froma

2016-12-01

With growing interest in systemic views of human resilience, this article updates and clarifies our understanding of the concept of resilience as involving multilevel dynamic processes over time. Family resilience refers to the functioning of the family system in dealing with adversity: Assessment and intervention focus on the family impact of stressful life challenges and the family processes that foster positive adaptation for the family unit and all members. The application of a family resilience framework is discussed and illustrated in clinical and community-based training and practice. Use of the author's research-informed map of core processes in family resilience is briefly noted, highlighting the recursive and synergistic influences of transactional processes within families and with their social environment. Given the inherently contextual nature of the construct of resilience, varied process elements may be more or less useful, depending on different adverse situations over time, with a major crisis; disruptive transitions; or chronic multistress conditions. This perspective is attuned to the diversity of family cultures and structures, their resources and constraints, socio-cultural and developmental influences, and the viability of varied pathways in resilience. © 2016 Family Process Institute.

Adaptation to high throughput batch chromatography enhances multivariate screening.

PubMed

Barker, Gregory A; Calzada, Joseph; Herzer, Sibylle; Rieble, Siegfried

2015-09-01

High throughput process development offers unique approaches to explore complex process design spaces with relatively low material consumption. Batch chromatography is one technique that can be used to screen chromatographic conditions in a 96-well plate. Typical batch chromatography workflows examine variations in buffer conditions or comparison of multiple resins in a given process, as opposed to the assessment of protein loading conditions in combination with other factors. A modification to the batch chromatography paradigm is described here where experimental planning, programming, and a staggered loading approach increase the multivariate space that can be explored with a liquid handling system. The iterative batch chromatography (IBC) approach is described, which treats every well in a 96-well plate as an individual experiment, wherein protein loading conditions can be varied alongside other factors such as wash and elution buffer conditions. As all of these factors are explored in the same experiment, the interactions between them are characterized and the number of follow-up confirmatory experiments is reduced. This in turn improves statistical power and throughput. Two examples of the IBC method are shown and the impact of the load conditions are assessed in combination with the other factors explored. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sensitivity of chemical weathering and dissolved carbon dynamics to hydrological conditions in a typical karst river

PubMed Central

Zhong, Jun; Li, Si-liang; Tao, Faxiang; Yue, Fujun; Liu, Cong-Qiang

2017-01-01

To better understand the mechanisms that hydrological conditions control chemical weathering and carbon dynamics in the large rivers, we investigated hydrochemistry and carbon isotopic compositions of dissolved inorganic carbon (DIC) based on high-frequency sampling in the Wujiang River draining the carbonate area in southwestern China. Concentrations of major dissolved solute do not strictly follow the dilution process with increasing discharge, and biogeochemical processes lead to variability in the concentration-discharge relationships. Temporal variations of dissolved solutes are closely related to weathering characteristics and hydrological conditions in the rainy seasons. The concentrations of dissolved carbon and the carbon isotopic compositions vary with discharge changes, suggesting that hydrological conditions and biogeochemical processes control dissolved carbon dynamics. Biological CO2 discharge and intense carbonate weathering by soil CO2 should be responsible for the carbon variability under various hydrological conditions during the high-flow season. The concentration of DICbio (DIC from biological sources) derived from a mixing model increases with increasing discharge, indicating that DICbio influx is the main driver of the chemostatic behaviors of riverine DIC in this typical karst river. The study highlights the sensitivity of chemical weathering and carbon dynamics to hydrological conditions in the riverine system. PMID:28220859

Study of the joining of polycarbonate panels in butt joint configuration through friction stir welding

NASA Astrophysics Data System (ADS)

Astarita, Antonello; Boccarusso, Luca; Carrino, Luigi; Durante, Massimo; Minutolo, Fabrizio Memola Capece; Squillace, Antonino

2018-05-01

Polycarbonate sheets, 3 mm thick, were successfully friction stir welded in butt joint configuration. Aiming to study the feasibility of the process and the influence of the process parameters joints under different processing conditions, obtained by varying the tool rotational speed and the tool travel speed, were realized. Tensile tests were carried out to characterize the joints. Moreover the forces arising during the process were recorded and carefully studied. The experimental outcomes proved the feasibility of the process when the process parameters are properly set, joints retaining more than 70% of the UTS of the base material were produced. The trend of the forces was described and explained, the influence of the process parameters was also introduced.

The effect of process parameters on audible acoustic emissions from high-shear granulation.

PubMed

Hansuld, Erin M; Briens, Lauren; Sayani, Amyn; McCann, Joe A B

2013-02-01

Product quality in high-shear granulation is easily compromised by minor changes in raw material properties or process conditions. It is desired to develop a process analytical technology (PAT) that can monitor the process in real-time and provide feedback for quality control. In this work, the application of audible acoustic emissions (AAEs) as a PAT tool was investigated. A condenser microphone was placed at the top of the air exhaust on a PMA-10 high-shear granulator to collect AAEs for a design of experiment (DOE) varying impeller speed, total binder volume and spray rate. The results showed the 10 Hz total power spectral densities (TPSDs) between 20 and 250 Hz were significantly affected by the changes in process conditions. Impeller speed and spray rate were shown to have statistically significant effects on granulation wetting, and impeller speed and total binder volume were significant in terms of process end-point. The DOE results were confirmed by a multivariate PLS model of the TPSDs. The scores plot showed separation based on impeller speed in the first component and spray rate in the second component. The findings support the use of AAEs to monitor changes in process conditions in real-time and achieve consistent product quality.

A Correlation-based Framework for Evaluating Postural Control Stochastic Dynamics

PubMed Central

Hernandez, Manuel E.; Snider, Joseph; Stevenson, Cory; Cauwenberghs, Gert; Poizner, Howard

2016-01-01

The inability to maintain balance during varying postural control conditions can lead to falls, a significant cause of mortality and serious injury among older adults. However, our understanding of the underlying dynamical and stochastic processes in human postural control have not been fully explored. To further our understanding of the underlying dynamical processes, we examine a novel conceptual framework for studying human postural control using the center of pressure (COP) velocity autocorrelation function (COP-VAF) and compare its results to Stabilogram Diffusion Analysis (SDA). Eleven healthy young participants were studied under quiet unipedal or bipedal standing conditions with eyes either opened or closed. COP trajectories were analyzed using both the traditional posturographic measure SDA and the proposed COP-VAF. It is shown that the COP-VAF leads to repeatable, physiologically meaningful measures that distinguish postural control differences in unipedal versus bipedal stance trials with and without vision in healthy individuals. More specifically, both a unipedal stance and lack of visual feedback increased initial values of the COP-VAF, magnitude of the first minimum, and diffusion coefficient, particularly in contrast to bipedal stance trials with open eyes. Use of a stochastic postural control model, based on an Ornstein-Uhlenbeck process that accounts for natural weight-shifts, suggests an increase in spring constant and decreased damping coefficient when fitted to experimental data. This work suggests that we can further extend our understanding of the underlying mechanisms behind postural control in quiet stance under varying stance conditions using the COP-VAF and provides a tool for quantifying future neurorehabilitative interventions. PMID:26011886

77 FR 52397 - Federal Property Suitable as Facilities To Assist the Homeless

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-29

...: 26305, 40132 Comments: Off-site removal only; sf. varies; use varies; fair conditions; restricted area..., 912, 913 Comments: Off-site removal only; sf varies; housing; fair to poor conditions; asbestos and...; office space; fair to poor conditions; secured area; prior approval to access property 258 7th Division...

INVESTIGATING SURFACE WATER QUALITY IMPACTS ON GROUNDWATER QUALITY UNDER VARYING FLOW CONDITIONS IN THE BARTON SPRINGS SEGMENT OF THE EDWARDS AQUIFER, CENTRAL TEXAS

EPA Science Inventory

The expected results from this research include: i) the quantification of the proportion of surface water comprising spring discharge under varying flow conditions; ii) the characterization of surface watersheds under varying antecedent moisture conditions, and evaluation of ...

Stochastic simulation by image quilting of process-based geological models

NASA Astrophysics Data System (ADS)

Hoffimann, Júlio; Scheidt, Céline; Barfod, Adrian; Caers, Jef

2017-09-01

Process-based modeling offers a way to represent realistic geological heterogeneity in subsurface models. The main limitation lies in conditioning such models to data. Multiple-point geostatistics can use these process-based models as training images and address the data conditioning problem. In this work, we further develop image quilting as a method for 3D stochastic simulation capable of mimicking the realism of process-based geological models with minimal modeling effort (i.e. parameter tuning) and at the same time condition them to a variety of data. In particular, we develop a new probabilistic data aggregation method for image quilting that bypasses traditional ad-hoc weighting of auxiliary variables. In addition, we propose a novel criterion for template design in image quilting that generalizes the entropy plot for continuous training images. The criterion is based on the new concept of voxel reuse-a stochastic and quilting-aware function of the training image. We compare our proposed method with other established simulation methods on a set of process-based training images of varying complexity, including a real-case example of stochastic simulation of the buried-valley groundwater system in Denmark.

Operation of the solvent-refined-coal pilot plant, Wilsonville, Alabama. Annual technical report, January-December 1980

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

Lewis, H.E.

1981-08-01

The plant was in operation for the equivalent of 247 days, an on-stream factor of 67.7%. Kentucky 9 coals from the Lafayette, Dotiki and Fies mines were processed. During 1980, the operating conditions and equipment were adjusted to evaluate potential process improvements. These experiments produced significant results in the following areas: Operating V103 High Pressure Separator in the hot mode; varying T102 Vacuum Column operating temperature; adding light SRC (LSRC), a product of the third stage of the Critical Solvent Deashing (CSD) unit, to the process solvent; investigating the effects of the chlorine content of the feed coal on corrosionmore » in the process vessels; evaluating the effects of adding sodium carbonate on corrosion rates; operating under conditions of low severity; i.e., low reactor temperature and long residence time; and testing an alternate CSD deashing solvent. A series of simulation runs investigating the design operating conditions for a planned 6000 ton per day SRC-I demonstation plant were also completed. Numerous improvements were made in the CSD processing area, and the components for a hydrotreating unit were installed.« less

Carbonaceous aerosols from prescribed burning of a boreal forest ecosystem

NASA Technical Reports Server (NTRS)

Mazurek, Monica A.; Cofer, Wesley R., III; Levine, Joel S.

1991-01-01

During the boreal forest burn studied, the ambient concentrations for the particle carbon smoke aerosol are highest for the full-fire burn conditions and vary significantly throughout the burn. Collection strategies must accordingly define ranges in the smoke aerosol concentrations produced. While the highest elemental C concentrations are observed during full-fire conditions, the great majority of smoke aerosol particles are in the form of organic C particles irrespective of fire temperature. The formation of organic C light-scattering particles was a significant process in the burn studied.

Quantifying the effect of varying GHG's concentration in Regional Climate Models

NASA Astrophysics Data System (ADS)

López-Romero, Jose Maria; Jerez, Sonia; Palacios-Peña, Laura; José Gómez-Navarro, Juan; Jiménez-Guerrero, Pedro; Montavez, Juan Pedro

2017-04-01

Regional Climate Models (RCMs) are driven at the boundaries by Global Circulation Models (GCM), and in the particular case of Climate Change projections, such simulations are forced by varying greenhouse gases (GHGs) concentrations. In hindcast simulations driven by reanalysis products, the climate change signal is usually introduced in the assimilation process as well. An interesting question arising in this context is whether GHGs concentrations have to be varied within the RCMs model itself, or rather they should be kept constant. Some groups keep the GHGs concentrations constant under the assumption that information about climate change signal is given throughout the boundaries; sometimes certain radiation parameterization schemes do not permit such changes. Other approaches vary these concentrations arguing that this preserves the physical coherence respect to the driving conditions for the RCM. This work aims to shed light on this topic. For this task, various regional climate simulations with the WRF model for the 1954-2004 period have been carried out for using a Euro-CORDEX compliant domain. A series of simulations with constant and variable GHGs have been performed using both, a GCM (ECHAM6-OM) and a reanalysis product (ERA-20C) data. Results indicate that there exist noticeable differences when introducing varying GHGs concentrations within the RCM domain. The differences in 2-m temperature series between the experiments with varying or constant GHGs concentration strongly depend on the atmospheric conditions, appearing a strong interannual variability. This suggests that short-term experiments are not recommended if the aim is to assess the role of varying GHGs. In addition, and consistently in both GCM and reanalysis-driven experiments, the magnitude of temperature trends, as well as the spatial pattern represented by varying GHGs experiment, are closer to the driving dataset than in experiments keeping constant the GHGs concentration. These results point towards the need for the inclusion of varying GHGs concentration within the RCM itself when dynamically downscaling global datasets, both in GCM and hindcast simulations.

Tuning relaxation dynamics and mechanical properties of polymer films of identical thickness

NASA Astrophysics Data System (ADS)

Kchaou, Marwa; Alcouffe, Pierre; Chandran, Sivasurender; Cassagnau, Philippe; Reiter, Günter; Al Akhrass, Samer

2018-03-01

Using dewetting as a characterization tool, we demonstrate that physical properties of thin polymer films can be regulated and tuned by employing variable processing conditions. For different molecular weights, the variable behavior of polystyrene films of identical thickness, prepared along systematically altered pathways, became predictable through a single parameter P , defined as the ratio of time required over time available for the equilibration of polymers. In particular, preparation-induced residual stresses, the corresponding relaxation times as well as the rupture probability of such films (of identical thickness) varied by orders of magnitude following scaling relations with P . Our experimental findings suggest that we can predictably enhance properties and hence maximize the performance of thin polymer films via appropriately chosen processing conditions.

Effects of set-size and lateral masking in visual search.

PubMed

Põder, Endel

2004-01-01

In the present research, the roles of lateral masking and central processing limitations in visual search were studied. Two search conditions were used: (1) target differed from distractors by presence/absence of a simple feature; (2) target differed by relative position of the same components only. The number of displayed stimuli (set-size) and the distance between neighbouring stimuli were varied as independently as possible in order to measure the effect of both. The effect of distance between stimuli (lateral masking) was found to be similar in both conditions. The effect of set-size was much larger for relative position stimuli. The results support the view that perception of relative position of stimulus components is limited mainly by the capacity of central processing.

Cooling the vertical surface by conditionally single pulses

NASA Astrophysics Data System (ADS)

Karpov, Pavel; Nazarov, Alexander; Serov, Anatoly; Terekhov, Victor

2017-10-01

You Sprays with periodic supply of the droplet phase have great opportunities to control the heat exchange processes. Varying pulse duration and frequency of their repetition, we can achieve the optimal conditions of evaporative cooling with minimization of the liquid flow rate. The paper presents experimental data on studying local heat transfer on a large subcooled surface, obtained on the original setup with multinozzle controlled system of impact irrigation by the gas-droplet flow. A contribution to intensification of the spray parameters (flow rate, pulse duration, repetition frequency) per a growth of integral heat transfer was studied. Data on instantaneous distribution of the heat flux value helped us to describe the processes occurring on the studied surface. These data could describe the regime of "island" film cooling.

Heterogeneity within the frontoparietal control network and its relationship to the default and dorsal attention networks.

PubMed

Dixon, Matthew L; De La Vega, Alejandro; Mills, Caitlin; Andrews-Hanna, Jessica; Spreng, R Nathan; Cole, Michael W; Christoff, Kalina

2018-02-13

The frontoparietal control network (FPCN) plays a central role in executive control. It has been predominantly viewed as a unitary domain general system. Here, we examined patterns of FPCN functional connectivity (FC) across multiple conditions of varying cognitive demands, to test for FPCN heterogeneity. We identified two distinct subsystems within the FPCN based on hierarchical clustering and machine learning classification analyses of within-FPCN FC patterns. These two FPCN subsystems exhibited distinct patterns of FC with the default network (DN) and the dorsal attention network (DAN). FPCN A exhibited stronger connectivity with the DN than the DAN, whereas FPCN B exhibited the opposite pattern. This twofold FPCN differentiation was observed across four independent datasets, across nine different conditions (rest and eight tasks), at the level of individual-participant data, as well as in meta-analytic coactivation patterns. Notably, the extent of FPCN differentiation varied across conditions, suggesting flexible adaptation to task demands. Finally, we used meta-analytic tools to identify several functional domains associated with the DN and DAN that differentially predict activation in the FPCN subsystems. These findings reveal a flexible and heterogeneous FPCN organization that may in part emerge from separable DN and DAN processing streams. We propose that FPCN A may be preferentially involved in the regulation of introspective processes, whereas FPCN B may be preferentially involved in the regulation of visuospatial perceptual attention.

Temporal Information Partitioning Networks (TIPNets): A process network approach to infer ecohydrologic shifts

NASA Astrophysics Data System (ADS)

Goodwell, Allison E.; Kumar, Praveen

2017-07-01

In an ecohydrologic system, components of atmospheric, vegetation, and root-soil subsystems participate in forcing and feedback interactions at varying time scales and intensities. The structure of this network of complex interactions varies in terms of connectivity, strength, and time scale due to perturbations or changing conditions such as rainfall, drought, or land use. However, characterization of these interactions is difficult due to multivariate and weak dependencies in the presence of noise, nonlinearities, and limited data. We introduce a framework for Temporal Information Partitioning Networks (TIPNets), in which time-series variables are viewed as nodes, and lagged multivariate mutual information measures are links. These links are partitioned into synergistic, unique, and redundant information components, where synergy is information provided only jointly, unique information is only provided by a single source, and redundancy is overlapping information. We construct TIPNets from 1 min weather station data over several hour time windows. From a comparison of dry, wet, and rainy conditions, we find that information strengths increase when solar radiation and surface moisture are present, and surface moisture and wind variability are redundant and synergistic influences, respectively. Over a growing season, network trends reveal patterns that vary with vegetation and rainfall patterns. The framework presented here enables us to interpret process connectivity in a multivariate context, which can lead to better inference of behavioral shifts due to perturbations in ecohydrologic systems. This work contributes to more holistic characterizations of system behavior, and can benefit a wide variety of studies of complex systems.

Robust sensor fault detection and isolation of gas turbine engines subjected to time-varying parameter uncertainties

NASA Astrophysics Data System (ADS)

Pourbabaee, Bahareh; Meskin, Nader; Khorasani, Khashayar

2016-08-01

In this paper, a novel robust sensor fault detection and isolation (FDI) strategy using the multiple model-based (MM) approach is proposed that remains robust with respect to both time-varying parameter uncertainties and process and measurement noise in all the channels. The scheme is composed of robust Kalman filters (RKF) that are constructed for multiple piecewise linear (PWL) models that are constructed at various operating points of an uncertain nonlinear system. The parameter uncertainty is modeled by using a time-varying norm bounded admissible structure that affects all the PWL state space matrices. The robust Kalman filter gain matrices are designed by solving two algebraic Riccati equations (AREs) that are expressed as two linear matrix inequality (LMI) feasibility conditions. The proposed multiple RKF-based FDI scheme is simulated for a single spool gas turbine engine to diagnose various sensor faults despite the presence of parameter uncertainties, process and measurement noise. Our comparative studies confirm the superiority of our proposed FDI method when compared to the methods that are available in the literature.

The Effects of Conflict, Quality and Time on Small Group Information Use and Behavior in Evaluative Decision-Making Situations.

ERIC Educational Resources Information Center

Pflum, Glenn D.; Brown, Robert D.

This study investigated information needs and use by groups in decision-making processes. Problem contexts were varied by conflict, quality, and time conditions and presented to 89 graduate level education students who simulated school board members making decisions about educational programs. The research hypotheses were: (1) there are no…

Kennedy Space Center environmental health program

NASA Technical Reports Server (NTRS)

Marmaro, G. M.; Cardinale, M. A.; Summerfield, B. R.; Tipton, D. A.

1992-01-01

The Kennedy Space Center's environmental health organization is responsible for programs which assure its employees a healthful workplace under diverse and varied working conditions. These programs encompass the disciplines of industrial hygiene, radiation protection (health physics), and environmental sanitation/pollution control. Activities range from the routine, such as normal office work, to the highly specialized, such as the processing of highly toxic and hazardous materials.

Face Recognition Is Affected by Similarity in Spatial Frequency Range to a Greater Degree Than Within-Category Object Recognition

ERIC Educational Resources Information Center

Collin, Charles A.; Liu, Chang Hong; Troje, Nikolaus F.; McMullen, Patricia A.; Chaudhuri, Avi

2004-01-01

Previous studies have suggested that face identification is more sensitive to variations in spatial frequency content than object recognition, but none have compared how sensitive the 2 processes are to variations in spatial frequency overlap (SFO). The authors tested face and object matching accuracy under varying SFO conditions. Their results…

The Entrance of Women into the Teaching Profession in Spain (1855-1940)

ERIC Educational Resources Information Center

de Gabriel, Narciso

2014-01-01

The admission of women to the teaching field was conditioned by many different circumstances that varied depending on time and place. This article will examine the evolution of this process in Spain in an attempt to identify some of the contributing factors: a patriarchal mentality which held that women had a special aptitude for teaching; a…

Independent and additive repetition priming of motion direction and color in visual search.

PubMed

Kristjánsson, Arni

2009-03-01

Priming of visual search for Gabor patch stimuli, varying in color and local drift direction, was investigated. The task relevance of each feature varied between the different experimental conditions compared. When the target defining dimension was color, a large effect of color repetition was seen as well as a smaller effect of the repetition of motion direction. The opposite priming pattern was seen when motion direction defined the target--the effect of motion direction repetition was this time larger than for color repetition. Finally, when neither was task relevant, and the target defining dimension was the spatial frequency of the Gabor patch, priming was seen for repetition of both color and motion direction, but the effects were smaller than in the previous two conditions. These results show that features do not necessarily have to be task relevant for priming to occur. There is little interaction between priming following repetition of color and motion, these two features show independent and additive priming effects, most likely reflecting that the two features are processed at separate processing sites in the nervous system, consistent with previous findings from neuropsychology & neurophysiology. The implications of the findings for theoretical accounts of priming in visual search are discussed.

Welding quality evaluation of resistance spot welding using the time-varying inductive reactance signal

NASA Astrophysics Data System (ADS)

Zhang, Hongjie; Hou, Yanyan; Yang, Tao; Zhang, Qian; Zhao, Jian

2018-05-01

In the spot welding process, a high alternating current is applied, resulting in a time-varying electromagnetic field surrounding the welder. When measuring the welding voltage signal, the impedance of the measuring circuit consists of two parts: dynamic resistance relating to weld nugget nucleation event and inductive reactance caused by mutual inductance. The aim of this study is to develop a method to acquire the dynamic reactance signal and to discuss the possibility of using this signal to evaluate the weld quality. For this purpose, a series of experiments were carried out. The reactance signals under different welding conditions were compared and the results showed that the morphological feature of the reactance signal was closely related to the welding current and it was also significantly influenced by some abnormal welding conditions. Some features were extracted from the reactance signal and combined to construct weld nugget strength and diameter prediction models based on the radial basis function (RBF) neural network. In addition, several features were also used to monitor the expulsion in the welding process by using Fisher linear discriminant analysis. The results indicated that using the dynamic reactance signal to evaluate weld quality is possible and feasible.

Comparison of turbulence mitigation algorithms

NASA Astrophysics Data System (ADS)

Kozacik, Stephen T.; Paolini, Aaron; Sherman, Ariel; Bonnett, James; Kelmelis, Eric

2017-07-01

When capturing imagery over long distances, atmospheric turbulence often degrades the data, especially when observation paths are close to the ground or in hot environments. These issues manifest as time-varying scintillation and warping effects that decrease the effective resolution of the sensor and reduce actionable intelligence. In recent years, several image processing approaches to turbulence mitigation have shown promise. Each of these algorithms has different computational requirements, usability demands, and degrees of independence from camera sensors. They also produce different degrees of enhancement when applied to turbulent imagery. Additionally, some of these algorithms are applicable to real-time operational scenarios while others may only be suitable for postprocessing workflows. EM Photonics has been developing image-processing-based turbulence mitigation technology since 2005. We will compare techniques from the literature with our commercially available, real-time, GPU-accelerated turbulence mitigation software. These comparisons will be made using real (not synthetic), experimentally obtained data for a variety of conditions, including varying optical hardware, imaging range, subjects, and turbulence conditions. Comparison metrics will include image quality, video latency, computational complexity, and potential for real-time operation. Additionally, we will present a technique for quantitatively comparing turbulence mitigation algorithms using real images of radial resolution targets.

Controllable growth of shaped graphene domains by atmospheric pressure chemical vapour deposition

NASA Astrophysics Data System (ADS)

Fan, Lili; Li, Zhen; Li, Xiao; Wang, Kunlin; Zhong, Minlin; Wei, Jinquan; Wu, Dehai; Zhu, Hongwei

2011-12-01

Graphene domains in different shapes have been grown on copper substrates via atmospheric pressure chemical vapour deposition by controlling the growth process parameters. Under stabilized conditions, graphene domains tend to be six-fold symmetric hexagons under low flow rate methane with some domains in an irregular hexagonal shape. After further varying the growth duration, methane flow rate, and temperature, graphene domains have developed shapes from hexagon to shovel and dendrite. Two connecting modes, through overlap and merging of adjacent graphene domains, are proposed.Graphene domains in different shapes have been grown on copper substrates via atmospheric pressure chemical vapour deposition by controlling the growth process parameters. Under stabilized conditions, graphene domains tend to be six-fold symmetric hexagons under low flow rate methane with some domains in an irregular hexagonal shape. After further varying the growth duration, methane flow rate, and temperature, graphene domains have developed shapes from hexagon to shovel and dendrite. Two connecting modes, through overlap and merging of adjacent graphene domains, are proposed. Electronic supplementary information (ESI) available: Schematics of CVD setups for graphene growth, Raman spectra and SEM images. See DOI: 10.1039/c1nr11480h

Averaging Principle for the Higher Order Nonlinear Schrödinger Equation with a Random Fast Oscillation

NASA Astrophysics Data System (ADS)

Gao, Peng

2018-06-01

This work concerns the problem associated with averaging principle for a higher order nonlinear Schrödinger equation perturbed by a oscillating term arising as the solution of a stochastic reaction-diffusion equation evolving with respect to the fast time. This model can be translated into a multiscale stochastic partial differential equations. Stochastic averaging principle is a powerful tool for studying qualitative analysis of stochastic dynamical systems with different time-scales. To be more precise, under suitable conditions, we prove that there is a limit process in which the fast varying process is averaged out and the limit process which takes the form of the higher order nonlinear Schrödinger equation is an average with respect to the stationary measure of the fast varying process. Finally, by using the Khasminskii technique we can obtain the rate of strong convergence for the slow component towards the solution of the averaged equation, and as a consequence, the system can be reduced to a single higher order nonlinear Schrödinger equation with a modified coefficient.

Averaging Principle for the Higher Order Nonlinear Schrödinger Equation with a Random Fast Oscillation

NASA Astrophysics Data System (ADS)

Gao, Peng

2018-04-01

This work concerns the problem associated with averaging principle for a higher order nonlinear Schrödinger equation perturbed by a oscillating term arising as the solution of a stochastic reaction-diffusion equation evolving with respect to the fast time. This model can be translated into a multiscale stochastic partial differential equations. Stochastic averaging principle is a powerful tool for studying qualitative analysis of stochastic dynamical systems with different time-scales. To be more precise, under suitable conditions, we prove that there is a limit process in which the fast varying process is averaged out and the limit process which takes the form of the higher order nonlinear Schrödinger equation is an average with respect to the stationary measure of the fast varying process. Finally, by using the Khasminskii technique we can obtain the rate of strong convergence for the slow component towards the solution of the averaged equation, and as a consequence, the system can be reduced to a single higher order nonlinear Schrödinger equation with a modified coefficient.

Scavenging rate ecoassay: a potential indicator of estuary condition.

PubMed

Porter, Augustine G; Scanes, Peter R

2015-01-01

Monitoring of estuary condition is essential due to the highly productive and often intensely impacted nature of these ecosystems. Assessment of the physico-chemical condition of estuaries is expensive and difficult due to naturally fluctuating water quality and biota. Assessing the vigour of ecosystem processes is an alternative method with potential to overcome much of the variability associated with physico-chemical measures. Indicators of estuary condition should have small spatial and temporal variability, have a predictable response to perturbation and be ecologically relevant. Here, we present tests of the first criterion, the spatio-temporal variability of a potential ecoassay measuring the rate of scavenging in estuaries. We hypothesised that the proposed scavenging ecoassay would not vary significantly among A) sites in an estuary, B) trips separated by weeks, or C) days in a trip. Because not all habitats are present in all estuaries, this test was undertaken in two habitats. When conducted over bare substrate there were occasional significant differences, but no discernible patterns, within levels of the experiment. When conducted over vegetated substrate, days within a trip did not vary significantly, but later trips experienced greater scavenging. This scavenging ecoassay shows potential as a tool for assessing the condition of estuarine ecosystems, and further exploration of this protocol is warranted by implementation in estuaries across a gradient of anthropogenic stress.

On the Principles of Building a Layered Intrusion

NASA Astrophysics Data System (ADS)

Marsh, B. D.

2009-12-01

An accurate and realistic understanding of all magmatic processes involves knowing the combined physical and chemical fundamentals governing the overall process. Magmatic processes involve such a vast array of sub-processes (e.g., heat and mass transfer, crystal growth, slurry transport and sorting, annealing, resorbtion, etc.) that rarely is there any single feature or measurement that can be safely inverted to solve the problem. And each event as in the formation of an intrusion must at some level for heuristic purposes be defined as an isolated event. This is commonly done without much forethought, as is the absolutely critical assumption of the initial conditions defining the beginning of the event. Almost without exception, it is the initial conditions that determine the outcome of the entire process in all physical and biological systems. Automobile factories produce motorized vehicles not water melons or chimpanzees. Nucleosynthesis of H and He always gives the same set of elements. The initial conditions of the magma giving rise to the end product for mafic layered systems are especially difficult to discern and must be bounded by observing simpler, real time magmatic and volcanic processes. Initial conditions come from posing a series of questions: What was the style and duration of filling? What was the rate of influx and final volume of each delivery of magma? What was the compositional variation and phenocryst content of the individual magmatic deliveries? If phenocrysts are present, were they sorted prior to injection during ascension? What was the original and ongoing shape of the magmatic reservoir? A failure to appreciate or answer such basic questions leads to vastly untenable evolutionary scenarios. Unrealistic initial conditions necessarily lead to unrealistic magmatic scenarios. There are certain safe starting points. Eruptive and emplacement fluxes are limited. The larger an intrusion is the longer it took to build and the longer to build the more varied are the deliveries in time, volume, and constitution. Instantaneous emplacement of crystal free magma are unlikely initial conditions for a large intrusion. The most realistic initial conditions are that intrusions are made of a combination of crystal poor and crystal-rich inputs. Examples abound of the outcomes of systems with clearly known initial conditions. The huge Sudbury magma was produced in 5 minutes at a temperature of 1700C. Clearly crystal free, it produced no layering whatsoever. Sills worldwide, regardless of size, approaching these initial conditions are similarly featureless. At the other extreme are the lava outputs of large volcanic systems like Kilauea. The ensuing lava lakes produced over months are filled with magma containing varied amounts of phenocrysts/xenocrysts and ultramafic layers are produced. Intrusions abound of all sizes that show the same characteristics. Ponding in crystal-laden sills forms layered systems with many of the features of large bodies. Rapid cooling preserves diagnostic textural relations lost to annealing in large bodies. Slow cooling promotes annealing to sharpen and accentuate the initial modal and cryptic layering. Initial conditions are fundamental to understanding the final product. Physical processes buttressed by chemistry mainly dominate magmatic systems.

The Phosphorylation State of the Drosophila TRP Channel Modulates the Frequency Response to Oscillating Light In Vivo

PubMed Central

Rhodes-Mordov, Elisheva; Katz, Ben; Oberegelsbacher, Claudia; Yasin, Bushra; Tzadok, Hanan; Huber, Armin

2017-01-01

Drosophila photoreceptors respond to oscillating light of high frequency (∼100 Hz), while the detected maximal frequency is modulated by the light rearing conditions, thus enabling high sensitivity to light and high temporal resolution. However, the molecular basis for this adaptive process is unclear. Here, we report that dephosphorylation of the light-activated transient receptor potential (TRP) ion channel at S936 is a fast, graded, light-dependent, and Ca2+-dependent process that is partially modulated by the rhodopsin phosphatase retinal degeneration C (RDGC). Electroretinogram measurements of the frequency response to oscillating lights in vivo revealed that dark-reared flies expressing wild-type TRP exhibited a detection limit of oscillating light at relatively low frequencies, which was shifted to higher frequencies upon light adaptation. Strikingly, preventing phosphorylation of the S936-TRP site by alanine substitution in transgenic Drosophila (trpS936A) abolished the difference in frequency response between dark-adapted and light-adapted flies, resulting in high-frequency response also in dark-adapted flies. In contrast, inserting a phosphomimetic mutation by substituting the S936-TRP site to aspartic acid (trpS936D) set the frequency response of light-adapted flies to low frequencies typical of dark-adapted flies. Light-adapted rdgC mutant flies showed relatively high S936-TRP phosphorylation levels and light–dark phosphorylation dynamics. These findings suggest that RDGC is one but not the only phosphatase involved in pS936-TRP dephosphorylation. Together, this study indicates that TRP channel dephosphorylation is a regulatory process that affects the detection limit of oscillating light according to the light rearing condition, thus adjusting dynamic processing of visual information under varying light conditions. SIGNIFICANCE STATEMENT Drosophila photoreceptors exhibit high temporal resolution as manifested in frequency response to oscillating light of high frequency (≤∼100 Hz). Light rearing conditions modulate the maximal frequency detected by photoreceptors, thus enabling them to maintain high sensitivity to light and high temporal resolution. However, the precise mechanisms for this process are not fully understood. Here, we show by combination of biochemistry and in vivo electrophysiology that transient receptor potential (TRP) channel dephosphorylation at a specific site is a fast, light-activated and Ca2+-dependent regulatory process. TRP dephosphorylation affects the detection limit of oscillating light according to the adaptation state of the photoreceptor cells by shifting the detection limit to higher frequencies upon light adaptation. This novel mechanism thus adjusts dynamic processing of visual information under varying light conditions. PMID:28314815

Destruction of organic pollutants by cerium(IV) MEO process: a study on the influence of process conditions for EDTA mineralization.

PubMed

Balaji, Subramanian; Chung, Sang Joon; Matheswaran, Manickam; Vasilivich, Kokovkin Vasily; Moon, Il Shik

2008-02-11

The mediated electrochemical oxidation (MEO) process with cerium(IV) and nitric acid as the oxidizing medium was employed for the destruction of various model organic pollutants in continuous organic feeding mode. A near complete destruction was observed for all the organics studied. The effects of various experimental conditions were evaluated with respect to EDTA mineralization. The key parameters varied in the process were concentration of EDTA (67-268 mM), temperature (70, 80 and 95 degrees C), concentrations of Ce(IV) (0.7, 0.8 and 0.95 M), nitric acid (2, 3 and 4M) and duration of organic addition (30 and 120 min). Under the experimental conditions of 80 degrees C and 0.95 M Ce(IV) in 3 M nitric acid, nearly 90% destruction was achieved based on CO(2) production and 95% based on TOC analyses for all the organic compounds studied. The in situ regeneration of mediator ion by the electrochemical cell was found to be good during the organic destruction within the range of experimental conditions studied. In the case of long term organic feeding (120 min) the destruction was calculated after the CO(2) evolution attained the steady state and under this condition the destruction efficiency was found to be 85% based on CO(2) evolution.

Dissociation between morality and disgust: an event-related potential study.

PubMed

Yang, Qun; Li, An; Xiao, Xiao; Zhang, Ye; Tian, Xuehong

2014-10-01

This study explored the neural correlates of morality and disgust, particularly, how the mechanisms that mediate our avoidance of physically disgusting and morally abhorrent behaviors are neurologically dissociated during the time-course of processing. Twelve participants were asked to judge the acceptability of different types of behaviors, which varied in their level of moral wrongness and physical disgust, while event-related potentials (ERPs) were recorded. The main results showed that the two morally wrong conditions elicited greater amplitudes of P300-400 at frontal sites than the neutral condition and the physically disgusting, but not morally wrong, condition. The physically disgusting conditions (with and without moral content) elicited significantly more positive deflections in the 500-600 ms timeframe than the neutral condition at central-posterior sites. These findings indicate that our aversion to harmful substances in the physical environment and offensive behaviors in the social environment may be neurologically dissociable in the temporal dimension. Furthermore, the detection of moral violations may be processed earlier in time than that of physical disgust. Copyright © 2014 Elsevier B.V. All rights reserved.

Dysphoria and children's processing of supportive interactions.

PubMed

Shirk, S R; Van Horn, M; Leber, D

1997-06-01

This study examined the processing of supportive interactions by dysphoric and nondysphoric preteens and early adolescents. Seventy-two youngsters between the ages of 10 and 13 evaluated the supportiveness and helpfulness of standardized, videotaped interactions between a distressed preadolescent and a maternal figure. The tape presentations varied in terms of the level of depicted maternal support and instructional condition (degree of self-reference). The results indicated that dysphoric youngsters evaluated both the supportiveness and helpfulness of interactions less positively than nondysphoric agemates. Group differences in support evaluations were most pronounced in the self-referenced condition. The level of depicted support did not affect processing differences. Dysphoric subjects reported lower levels of emotional support in prior relationships and a greater tendency to view supportive behavior as ingenuine than nondysphoric peers. Variation in prior support experiences accounted for group differences in the evaluation of the supportiveness of new interactions.

Rain events and their effect on effluent quality studied at a full scale activated sludge treatment plant.

PubMed

Wilén, B M; Lumley, D; Mattsson, A; Mino, T

2006-01-01

The effect of rain events on effluent quality dynamics was studied at a full scale activated sludge wastewater treatment plant which has a process solution incorporating pre-denitrification in activated sludge with post-nitrification in trickling filters. The incoming wastewater flow varies significantly due to a combined sewer system. Changed flow conditions have an impact on the whole treatment process since the recirculation to the trickling filters is set by the hydraulic limitations of the secondary settlers. Apart from causing different hydraulic conditions in the plant, increased flow due to rain or snow-melting, changes the properties of the incoming wastewater which affects process performance and effluent quality, especially the particle removal efficiency. A comprehensive set of on-line and laboratory data were collected and analysed to assess the impact of rain events on the plant performance.

Decreasing diameter fluctuation of polymer optical fiber with optimized drawing conditions

NASA Astrophysics Data System (ADS)

Çetinkaya, Onur; Wojcik, Grzegorz; Mergo, Pawel

2018-05-01

The diameter fluctuations of poly(methyl methacrylate) based polymer optical fibers, during drawing processes, have been comprehensively studied. In this study, several drawing parameters were selected for investigation; such as drawing tensions, preform diameters, preform feeding speeds, and argon flows. Varied drawing tensions were used to draw fibers, while other parameters were maintained at constant. At a later stage in the process, micro-structured polymer optical fibers were drawn under optimized drawing conditions. Fiber diameter deviations were reduced to 2.2%, when a 0.2 N drawing tension was employed during the drawing process. Higher drawing tensions led to higher diameter fluctuations. The Young’s modulus of fibers drawn with different tensions was also measured. Our results showed that fiber elasticity increased as drawing tensions decreased. The inhomogeneity of fibers was also determined by comparing the deviation of Young’s modulus.

Poromechanics of stick-slip frictional sliding and strength recovery on tectonic faults

DOE PAGES

Scuderi, Marco M.; Carpenter, Brett M.; Johnson, Paul A.; ...

2015-10-22

Pore fluids influence many aspects of tectonic faulting including frictional strength aseismic creep and effective stress during the seismic cycle. But, the role of pore fluid pressure during earthquake nucleation and dynamic rupture remains poorly understood. Here we report on the evolution of pore fluid pressure and porosity during laboratory stick-slip events as an analog for the seismic cycle. We sheared layers of simulated fault gouge consisting of glass beads in a double-direct shear configuration under true triaxial stresses using drained and undrained fluid conditions and effective normal stress of 5–10 MPa. Shear stress was applied via a constant displacementmore » rate, which we varied in velocity step tests from 0.1 to 30 µm/s. Here, we observe net pore pressure increases, or compaction, during dynamic failure and pore pressure decreases, or dilation, during the interseismic period, depending on fluid boundary conditions. In some cases, a brief period of dilation is attendant with the onset of dynamic stick slip. Our data show that time-dependent strengthening and dynamic stress drop increase with effective normal stress and vary with fluid conditions. For undrained conditions, dilation and preseismic slip are directly related to pore fluid depressurization; they increase with effective normal stress and recurrence time. Microstructural observations confirm the role of water-activated contact growth and shear-driven elastoplastic processes at grain junctions. These results indicate that physicochemical processes acting at grain junctions together with fluid pressure changes dictate stick-slip stress drop and interseismic creep rates and thus play a key role in earthquake nucleation and rupture propagation.« less

Optimization of hydrostatic pressure at varied sonication conditions--power density, intensity, very low frequency--for isothermal ultrasonic sludge treatment.

PubMed

Delmas, Henri; Le, Ngoc Tuan; Barthe, Laurie; Julcour-Lebigue, Carine

2015-07-01

This work aims at investigating for the first time the key sonication (US) parameters: power density (DUS), intensity (IUS), and frequency (FS) - down to audible range, under varied hydrostatic pressure (Ph) and low temperature isothermal conditions (to avoid any thermal effect). The selected application was activated sludge disintegration, a major industrial US process. For a rational approach all comparisons were made at same specific energy input (ES, US energy per solid weight) which is also the relevant economic criterion. The decoupling of power density and intensity was obtained by either changing the sludge volume or most often by changing probe diameter, all other characteristics being unchanged. Comprehensive results were obtained by varying the hydrostatic pressure at given power density and intensity. In all cases marked maxima of sludge disintegration appeared at optimum pressures, which values increased at increasing power intensity and density. Such optimum was expected due to opposite effects of increasing hydrostatic pressure: higher cavitation threshold then smaller and fewer bubbles, but higher temperature and pressure at the end of collapse. In addition the first attempt to lower US frequency down to audible range was very successful: at any operation condition (DUS, IUS, Ph, sludge concentration and type) higher sludge disintegration was obtained at 12 kHz than at 20 kHz. The same values of optimum pressure were observed at 12 and 20 kHz. At same energy consumption the best conditions - obtained at 12 kHz, maximum power density 720 W/L and 3.25 bar - provided about 100% improvement with respect to usual conditions (1 bar, 20 kHz). Important energy savings and equipment size reduction may then be expected. Copyright © 2014 Elsevier B.V. All rights reserved.

Multiple drivers, scales, and interactions influence southern Appalachian stream salamander occupancy

USGS Publications Warehouse

Cecala, Kristen K.; Maerz, John C.; Halstead, Brian J.; Frisch, John R.; Gragson, Ted L.; Hepinstall-Cymerman, Jeffrey; Leigh, David S.; Jackson, C. Rhett; Peterson, James T.; Pringle, Catherine M.

2018-01-01

Understanding how factors that vary in spatial scale relate to population abundance is vital to forecasting species responses to environmental change. Stream and river ecosystems are inherently hierarchical, potentially resulting in organismal responses to fine‐scale changes in patch characteristics that are conditional on the watershed context. Here, we address how populations of two salamander species are affected by interactions among hierarchical processes operating at different scales within a rapidly changing landscape of the southern Appalachian Mountains. We modeled reach‐level occupancy of larval and adult black‐bellied salamanders (Desmognathus quadramaculatus) and larval Blue Ridge two‐lined salamanders (Eurycea wilderae) as a function of 17 different terrestrial and aquatic predictor variables that varied in spatial extent. We found that salamander occurrence varied widely among streams within fully forested catchments, but also exhibited species‐specific responses to changes in local conditions. While D. quadramaculatus declined predictably in relation to losses in forest cover, larval occupancy exhibited the strongest negative response to forest loss as well as decreases in elevation. Conversely, occupancy of E. wilderae was unassociated with watershed conditions, only responding negatively to higher proportions of fast‐flowing stream habitat types. Evaluation of hierarchical relationships demonstrated that most fine‐scale variables were closely correlated with broad watershed‐scale variables, suggesting that local reach‐scale factors have relatively smaller effects within the context of the larger landscape. Our results imply that effective management of southern Appalachian stream salamanders must first focus on the larger scale condition of watersheds before management of local‐scale conditions should proceed. Our findings confirm the results of some studies while refuting the results of others, which may indicate that prescriptive recommendations for range‐wide management of species or the application of a single management focus across large geographic areas is inappropriate.

Friction Stir Welding (FSW) of Aged CuCrZr Alloy Plates

NASA Astrophysics Data System (ADS)

Jha, Kaushal; Kumar, Santosh; Nachiket, K.; Bhanumurthy, K.; Dey, G. K.

2018-01-01

Friction Stir Welding (FSW) of Cu-0.80Cr-0.10Zr (in wt pct) alloy under aged condition was performed to study the effects of process parameters on microstructure and properties of the joint. FSW was performed over a wide range of process parameters, like tool-rotation speed (from 800 to 1200 rpm) and tool-travel speed (from 40 to 100 mm/min), and the resulting thermal cycles were recorded on both sides (advancing and retreating) of the joint. The joints were characterized for their microstructure and tensile properties. The welding process resulted in a sound and defect-free weld joint, over the entire range of the process parameters used in this study. Microstructure of the stir zone showed fine and equiaxed grains, the scale of which varied with FSW process parameters. Grain size in the stir zone showed direct correlation with tool rotation and inverse correlation with tool-travel speed. Tensile strength of the weld joints was ranging from 225 to 260 MPa, which is substantially lower than that of the parent metal under aged condition ( 400 MPa), but superior to that of the parent material under annealed condition ( 220 MPa). Lower strength of the FSW joint than that of the parent material under aged condition can be attributed to dissolution of the precipitates in the stir zone and TMAZ. These results are presented and discussed in this paper.

Impact of hydraulic and carbon loading rates of constructed wetlands on contaminants of emerging concern (CECs) removal.

PubMed

Sharif, Fariya; Westerhoff, Paul; Herckes, Pierre

2014-02-01

Constructed wetlands remove trace organic contaminants via synergistic processes involving plant biomass that include hydrolysis, volatilization, sorption, biodegradation, and photolysis. Wetland design conditions, such as hydraulic loading rates (HLRs) and carbon loading rates (CLRs), influence these processes. Contaminant of emerging concern (CEC) removal by wetland plants was investigated at varying HLRs and CLRs. Rate constants and parameters obtained from batch-scale studies were used in a mechanistic model to evaluate the effect of these two loading rates on CEC removal. CLR significantly influenced CEC removal when wetlands were operated at HLR >5 cm/d. High values of CLR increased removal of estradiol and carbamazepine but lowered that of testosterone and atrazine. Without increasing the cumulative HLR, operating two wetlands in series with varying CLRs could be a way to improve CEC removal. Copyright © 2013 Elsevier Ltd. All rights reserved.

Style follows content: on the microgenesis of art perception.

PubMed

Augustin, M Dorothee; Leder, Helmut; Hutzler, Florian; Carbon, Claus-Christian

2008-05-01

Despite fruitful research in experimental aesthetics, the dynamics of aesthetics, i.e., the processes involved in art perception, have received little attention. Concerning representational art, two aspects seem most important in this respect: style and content. In two experiments, we examined the dynamics of processing of style and content by means of the microgenetic approach. This approach systematically varies perceptual conditions to find out about the stages involved in the formation of percepts--their microgenesis. Participants gave similarity ratings for pairs of pictures that were fully crossed in style (artist) and content (motif). Presentation times were systematically varied between 10, 50, 202 and 3000 ms (Experiment 1) plus unlimited presentation time (Experiment 2). While effects of content were present at all presentation times, effects of style were traceable from 50 ms onwards. The results show clear differences in the microgenesis of style and content, suggesting that in art perception style follows content.

Robust fusion-based processing for military polarimetric imaging systems

NASA Astrophysics Data System (ADS)

Hickman, Duncan L.; Smith, Moira I.; Kim, Kyung Su; Choi, Hyun-Jin

2017-05-01

Polarisation information within a scene can be exploited in military systems to give enhanced automatic target detection and recognition (ATD/R) performance. However, the performance gain achieved is highly dependent on factors such as the geometry, viewing conditions, and the surface finish of the target. Such performance sensitivities are highly undesirable in many tactical military systems where operational conditions can vary significantly and rapidly during a mission. Within this paper, a range of processing architectures and fusion methods is considered in terms of their practical viability and operational robustness for systems requiring ATD/R. It is shown that polarisation information can give useful performance gains but, to retained system robustness, the introduction of polarimetric processing should be done in such a way as to not compromise other discriminatory scene information in the spectral and spatial domains. The analysis concludes that polarimetric data can be effectively integrated with conventional intensity-based ATD/R by either adapting the ATD/R processing function based on the scene polarisation or else by detection-level fusion. Both of these approaches avoid the introduction of processing bottlenecks and limit the impact of processing on system latency.

The selective processing of emotional visual stimuli while detecting auditory targets: an ERP analysis.

PubMed

Schupp, Harald T; Stockburger, Jessica; Bublatzky, Florian; Junghöfer, Markus; Weike, Almut I; Hamm, Alfons O

2008-09-16

Event-related potential studies revealed an early posterior negativity (EPN) for emotional compared to neutral pictures. Exploring the emotion-attention relationship, a previous study observed that a primary visual discrimination task interfered with the emotional modulation of the EPN component. To specify the locus of interference, the present study assessed the fate of selective visual emotion processing while attention is directed towards the auditory modality. While simply viewing a rapid and continuous stream of pleasant, neutral, and unpleasant pictures in one experimental condition, processing demands of a concurrent auditory target discrimination task were systematically varied in three further experimental conditions. Participants successfully performed the auditory task as revealed by behavioral performance and selected event-related potential components. Replicating previous results, emotional pictures were associated with a larger posterior negativity compared to neutral pictures. Of main interest, increasing demands of the auditory task did not modulate the selective processing of emotional visual stimuli. With regard to the locus of interference, selective emotion processing as indexed by the EPN does not seem to reflect shared processing resources of visual and auditory modality.

Dielectric Characterization of Mylar and The Effects of Doping Processes.

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

Belcher, Cami Beth

2016-11-01

Mylar® polymer is a bi-axially oriented polyethylene terephthalate (PET) polymer film used widely as a dielectric, specifically in capacitors. The dielectric characteristics of Mylar have been well studied and documented over the years; however, many of the mechanisms responsible for dielectric breakdown and failure are not understood for modified versions of the material. Previous studies on Mylar confirm that factors such as temperature, humidity, and voltage ramp rates can also have a significant effect on the dielectric properties and measurement of the dielectric properties. This study seeks to determine how dielectric properties, including permittivity, dielectric loss, and breakdown strength, aremore » affected by doping of the polymer. To do this, two types of Mylar films, virgin film and film doped with a small-molecule electron-acceptor, are tested. Both types of materials are tested under a variety of environmental and experimental conditions, including testing at elevated temperatures, varying relative humidity, and varying ramp rates in dielectric breakdown testing. Analysis of permittivity, dielectric loss, and breakdown strength will be presented comparing virgin and doped Mylar to gain insight into the effects of doping with electron-acceptor molecules on dielectric properties under these varying environmental and test conditions.« less

Nickel-hydrogen capacity loss on storage

NASA Technical Reports Server (NTRS)

Manzo, Michelle A.

1989-01-01

A controlled experiment evaluating the capacity loss experienced by nickel electrodes stored under various conditions of temperature, hydrogen pressure, and electrolyte concentration was conducted using nickel electrodes from four different manufacturers. It was found that capacity loss varied with respect to hydrogen pressure, and storage temperature as well as with respect to electrode manufacturing processes. Impedance characteristics were monitored and found to be indicative of electrode manufacturing processes and capacity loss. Cell testing to evaluate state-of-charge effects on capacity loss were inconclusive as no loss was sustained by the cells tested in this experiment.

Counterflow diffusion flame synthesis of ceramic oxide powders

DOEpatents

Katz, J.L.; Miquel, P.F.

1997-07-22

Ceramic oxide powders and methods for their preparation are revealed. Ceramic oxide powders are obtained using a flame process whereby one or more precursors of ceramic oxides are introduced into a counterflow diffusion flame burner wherein the precursors are converted into ceramic oxide powders. The nature of the ceramic oxide powder produced is determined by process conditions. The morphology, particle size, and crystalline form of the ceramic oxide powders may be varied by the temperature of the flame, the precursor concentration ratio, the gas stream and the gas velocity. 24 figs.

Counterflow diffusion flame synthesis of ceramic oxide powders

DOEpatents

Katz, Joseph L.; Miquel, Philippe F.

1997-01-01

Ceramic oxide powders and methods for their preparation are revealed. Ceramic oxide powders are obtained using a flame process whereby one or more precursors of ceramic oxides are introduced into a counterflow diffusion flame burner wherein the precursors are converted into ceramic oxide powders. The nature of the ceramic oxide powder produced is determined by process conditions. The morphology, particle size, and crystalline form of the ceramic oxide powders may be varied by the temperature of the flame, the precursor concentration ratio, the gas stream and the gas velocity.

Arbitrarily small amounts of correlation for arbitrarily varying quantum channels

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

Boche, H., E-mail: boche@tum.de, E-mail: janis.noetzel@tum.de; Nötzel, J., E-mail: boche@tum.de, E-mail: janis.noetzel@tum.de

2013-11-15

As our main result show that in order to achieve the randomness assisted message and entanglement transmission capacities of a finite arbitrarily varying quantum channel it is not necessary that sender and receiver share (asymptotically perfect) common randomness. Rather, it is sufficient that they each have access to an unlimited amount of uses of one part of a correlated bipartite source. This access might be restricted to an arbitrary small (nonzero) fraction per channel use, without changing the main result. We investigate the notion of common randomness. It turns out that this is a very costly resource – generically, itmore » cannot be obtained just by local processing of a bipartite source. This result underlines the importance of our main result. Also, the asymptotic equivalence of the maximal- and average error criterion for classical message transmission over finite arbitrarily varying quantum channels is proven. At last, we prove a simplified symmetrizability condition for finite arbitrarily varying quantum channels.« less

Comparing the effects of sustained and transient spatial attention on the orienting towards and the processing of electrical nociceptive stimuli.

PubMed

Van der Lubbe, Rob H J; Blom, Jorian H G; De Kleine, Elian; Bohlmeijer, Ernst T

2017-02-01

We examined whether sustained vs. transient spatial attention differentially affect the processing of electrical nociceptive stimuli. Cued nociceptive stimuli of a relevant intensity (low or high) on the left or right forearm required a foot pedal press. The cued side varied trial wise in the transient attention condition, while it remained constant during a series of trials in the sustained attention condition. The orienting phase preceding the nociceptive stimuli was examined by focusing on lateralized EEG activity. ERPs were computed to examine the influence of spatial attention on the processing of the nociceptive stimuli. Results for the orienting phase showed increased ipsilateral alpha and beta power above somatosensory areas in both the transient and the sustained attention conditions, which may reflect inhibition of ipsilateral and/or disinhibition of contralateral somatosensory areas. Cued nociceptive stimuli evoked a larger N130 than uncued stimuli, both in the transient and the sustained attention conditions. Support for increased efficiency of spatial attention in the sustained attention condition was obtained for the N180 and the P540 component. We concluded that spatial attention is more efficient in the case of sustained than in the case of transient spatial attention. Copyright © 2016 Elsevier B.V. All rights reserved.

Determinant impact of waste collection and composition on anaerobic digestion performance: industrial results.

PubMed

Saint-Joly, C; Desbois, S; Lotti, J P

2000-01-01

The performance of the anaerobic digestion process depends deeply on the quality of the waste to be treated. This has been already demonstrated at the lab-scale. The objective of this study is to confirm this result at the industrial scale, with very long representative period and with the same process, the Valorga process. According to the waste quality and the collection type and even with the same conditions of fermentation, the biogas yield can vary by a factor of 1.5 when it is expressed (under normal conditions of pressure and temperature) in m3 biogas/t fresh waste, and by a factor of 2 when it is expressed in m3 CH4/t volatile solids. So, the biogas performance does not characterise a process since it is deeply governed by waste composition. This biogas productivity becomes a pertinent parameter only with consistent and relevant hypothesis and/or analytical results on the waste composition which depends on the collection procedure, the site characteristics and the season.

Production and Characterization of Ethyl Ester from Crude Jatropha curcas Oil having High Free Fatty Acid Content

NASA Astrophysics Data System (ADS)

Kumar, Rajneesh; Dixit, Anoop; Singh, Shashi Kumar; Singh, Gursahib; Sachdeva, Monica

2015-09-01

The two step process was carried out to produce biodiesel from crude Jatropha curcas oil. The pretreatment process was carried out to reduce the free fatty acid content by (≤2 %) acid catalyzed esterification. The optimum reaction conditions for esterification were reported to be 5 % H2SO4, 20 % ethanol and 1 h reaction time at temperature of 65 °C. The pretreatment process reduced the free fatty acid of oil from 7 to 1.85 %. In second process, alkali catalysed transesterification of pretreated oil was carried and the effects of the varying concentrations of KOH and ethanol: oil ratios on percent ester recovery were investigated. The optimum reaction conditions for transesterification were reported to be 3 % KOH (w/v of oil) and 30 % (v/v) ethanol: oil ratio and reaction time 2 h at 65 °C. The maximum percent recovery of ethyl ester was reported to be 60.33 %.

Acetylene terminated matrix resins

NASA Technical Reports Server (NTRS)

Goldfarb, I. J.; Lee, Y. C.; Arnold, F. E.; Helminiak, T. E.

1985-01-01

The synthesis of resins with terminal acetylene groups has provided a promising technology to yield high performance structural materials. Because these resins cure through an addition reaction, no volatile by-products are produced during the processing. The cured products have high thermal stability and good properties retention after exposure to humidity. Resins with a wide variety of different chemical structures between the terminal acetylene groups are synthesized and their mechanical properties studied. The ability of the acetylene cured polymers to give good mechanical properties is demonstrated by the resins with quinoxaline structures. Processibility of these resins can be manipulated by varying the chain length between the acetylene groups or by blending in different amounts of reactive deluents. Processing conditions similar to the state-of-the-art epoxy can be attained by using backbone structures like ether-sulfone or bis-phenol-A. The wide range of mechanical properties and processing conditions attainable by this class of resins should allow them to be used in a wide variety of applications.

Trends in non-stationary signal processing techniques applied to vibration analysis of wind turbine drive train - A contemporary survey

NASA Astrophysics Data System (ADS)

Uma Maheswari, R.; Umamaheswari, R.

2017-02-01

Condition Monitoring System (CMS) substantiates potential economic benefits and enables prognostic maintenance in wind turbine-generator failure prevention. Vibration Monitoring and Analysis is a powerful tool in drive train CMS, which enables the early detection of impending failure/damage. In variable speed drives such as wind turbine-generator drive trains, the vibration signal acquired is of non-stationary and non-linear. The traditional stationary signal processing techniques are inefficient to diagnose the machine faults in time varying conditions. The current research trend in CMS for drive-train focuses on developing/improving non-linear, non-stationary feature extraction and fault classification algorithms to improve fault detection/prediction sensitivity and selectivity and thereby reducing the misdetection and false alarm rates. In literature, review of stationary signal processing algorithms employed in vibration analysis is done at great extent. In this paper, an attempt is made to review the recent research advances in non-linear non-stationary signal processing algorithms particularly suited for variable speed wind turbines.

Automaticity in reading and the Stroop task: testing the limits of involuntary word processing.

PubMed

Brown, Tracy L; Joneleit, Kelly; Robinson, Cathy S; Brown, Carli Rose

2002-01-01

We investigated the parameters of involuntary word reading in the Stroop task in 7 experiments. Experiments 1-4 varied response modality and the presence of congruent word trials in a test of the claim that presenting a Stroop color word with only one letter in the target color eliminates the Stroop effect. Experiments 5 and 6 addressed the roles of spatial attention and orthographic processing as possible mechanisms behind the reduction of Stroop effects with the single-letter format. Experiment 7 investigated the limits of involuntary reading under optimal conditions for selective processing of rectangular color patch targets. We found that the single-letter format reduced but never eliminated Stroop effects, spatial attention but not orthographic processing plays a role in the effect of the single-letter format, and word reading is not completely prevented even with austere presentation conditions. We conclude with a defense of the involuntariness criterion for automaticity in the Stroop task, particularly when word reading is viewed in the context of a skilled performance.

Advocate: A Distributed Architecture for Speech-to-Speech Translation

DTIC Science & Technology

2009-01-01

tecture, are either wrapped natural-language processing ( NLP ) components or objects developed from scratch using the architecture’s API. GATE is...framework, we put together a demonstration Arabic -to- English speech translation system using both internally developed ( Arabic speech recognition and MT...conditions of our Arabic S2S demonstration system described earlier. Once again, the data size was varied and eighty identical requests were

Vulnerability of carbon storage in North American boreal forests to wildfires during the 21st century

Treesearch

M.S. Balshi; A.D. McGuire; P. Duffy; M. Flannigan; D.W. Kicklighter; J. Melillo

2009-01-01

We use a gridded data set developed with a multivariate adaptive regression spline approach to determine how area burned varies each year with changing climatic and fuel moisture conditions. We apply the process-based Terrestrial Ecosystem Model to evaluate the role of future fire on the carbon dynamics of boreal North America in the context of changing atmospheric...

Preliminary results of fire behavior in maquis fuels under varying weather and slope conditions in turkey

Treesearch

Bulent Saglam; Ertugrul Bilgili; Omer Kucuk; Bahar Dinc Durmaz; Ismail Baysal

2007-01-01

The prediction of fire behavior is of vital importance to all fire management planning and decisionmaking processes including fire prevention, presuppression planning, and fire use. The effect of slope on fire behavior is well acknowledged, yet its effect on fire behavior is not well accounted for. Determining the effects of slope on fire behavior under field...

Genotype-environment interaction in passive avoidance learning of the paradise fish (Macropodus opercularis).

PubMed

Csányi, V; Gervai, J

1985-01-01

Passive dark avoidance conditioning and effects of the presence and absence of a fish-like dummy on the training process were studied in four inbred strains of paradise fish. Strain differences were found in the shuttle activity during habituation trials, and in the sensitivity to the mild electric shock punishment. The presence or absence of the dummy in the punished dark side of the shuttle box had a genotype-dependent effect on the measures taken during the conditioning process. The statistical analysis of the learning curves revealed differences in the way the strains varied in the different environments, i.e. genotype--environment interaction components of variances were identified. The results are discussed in the light of previous investigations and their implication in further genetic analysis.

Please Wait, Processing: A Selective Literature Review of the Neurological Understanding of Emotional Processing in ASD and Its Potential Contribution to Neuroeducation.

PubMed

Shyman, Eric

2017-11-17

Autism spectrum disorder (ASD) and its corresponding conditions have been investigated from a multitude of perspectives resulting in varying understandings of its origin, its outplay, its prognosis, and potential methods of intervention and education for individuals with the disorder. One area that has contributed significantly to providing a different type of understanding is that of neuroscience, and specifically neuroimaging. This paper will offer a selective literature review of research that investigates the role of emotional processing in ASD, and how a deepening of this line of understanding can be used to inform more comprehensive educational practices.

Light field and water clarity simulation of natural environments in laboratory conditions

NASA Astrophysics Data System (ADS)

Pe'eri, Shachak; Shwaery, Glenn

2012-06-01

Simulation of natural oceanic conditions in a laboratory setting is a challenging task, especially when that environment can be miles away. We present an attempt to replicate the solar radiation expected at different latitudes with varying water clarity conditions up to 30 m in depth using a 2.5 m deep engineering tank at the University of New Hampshire. The goals of the study were: 1) to configure an underwater light source that produced an irradiance spectrum similar to natural daylight with the sun at zenith and at 60° under clear atmospheric conditions, and 2) to monitor water clarity as a function of depth. Irradiance was measured using a spectra-radiometer with a cosine receiver to analyze the output spectrum of submersed lamps as a function of distance. In addition, an underwater reflection method was developed to measure the diffuse attenuation coefficient in real time. Two water clarity types were characterized, clear waters representing deep, open-ocean conditions, and murky waters representing littoral environments. Results showed good correlation between the irradiance measured at 400 nm to 600 nm and the natural daylight spectrum at 3 m from the light source. This can be considered the water surface conditions reference. Using these methodologies in a controlled laboratory setting, we are able to replicate illumination and water conditions to study the physical, chemical and biological processes on natural and man-made objects and/or systems in simulated, varied geographic locations and environments.

Conditioning of material properties by micro rotary swaging

NASA Astrophysics Data System (ADS)

Ishkina, Svetlana; Schenck, Christian; Kuhfuss, Bernd

2018-05-01

Cold forming initiates a change of the material properties like flow stress and hardness. Due to work hardening and the accompanied loss of formability some intermediate heat treatment may become necessary in multi-stage forming processes. One possibility to avoid this heat treatment is to adjust the forming characteristics in terms of flow stress and formability by rotary swaging. This process is particularly suitable not only for producing of the target geometry but also for modifying of the material properties during the process and thus, rotary swaging can prepare the parts for further forming, such as extrusion. In this contribution, the process chain "rotary swaging - extrusion" for austenite stainless steel AISI304 was investigated. The forming characteristics of the semi-finished products for the extrusion were influenced by the previous swaging process. The conditioning by changing of the microstructure, the work hardening and the geometry of the processed wires was achieved by the process design. For this purpose, the geometry of the swaging dies, the feeding velocity as well as the process kinematics (eccentric swaging) and a stroke following angle Δɸ were varied. In particular, the novel geometry of the swaging dies with extraordinary sloped faces generated a non-symmetric material flow with severe shear deformation and thus an extreme change of the microstructure. The required forming force of the following extrusion process reflected the range of achievable conditioning. The micro rotary swaging process positively improved the formability of AISI304 by work softening.

Simulation and experimental research on trans-media vehicle water-entry motion characteristics at low speed

PubMed Central

Yang, Jian; Feng, Jinfu; Hu, Junhua; Liu, An

2017-01-01

The motion characteristics of trans-media vehicles during the water-entry process were explored in this study in an effort to obtain the optimal water-entry condition of the vehicle for developing a novel, single control strategy integrating underwater non-control and in-air control. A water-entry dynamics model is established by combining the water-entry motion characteristics of the vehicle in uncontrolled conditions at low speed with time-varying parameters (e.g. buoyancy, added mass). A water-entry experiment is designed to confirm the effectiveness of the established model. After that, by comparing the experimental results with the simulated results, the model is further modified to more accurately reflect water-entry motion. The change laws of the vehicle’s attitude and position during the water-entry process are also obtained by analyzing the simulation of the modified model under different velocity, angle, and angle of attack conditions. The results presented here have guiding significance for the future realization of reaching the stable underwater navigation state of the vehicle after water-entry process. PMID:28558012

Simulation and experimental research on trans-media vehicle water-entry motion characteristics at low speed.

PubMed

Yang, Jian; Li, Yongli; Feng, Jinfu; Hu, Junhua; Liu, An

2017-01-01

The motion characteristics of trans-media vehicles during the water-entry process were explored in this study in an effort to obtain the optimal water-entry condition of the vehicle for developing a novel, single control strategy integrating underwater non-control and in-air control. A water-entry dynamics model is established by combining the water-entry motion characteristics of the vehicle in uncontrolled conditions at low speed with time-varying parameters (e.g. buoyancy, added mass). A water-entry experiment is designed to confirm the effectiveness of the established model. After that, by comparing the experimental results with the simulated results, the model is further modified to more accurately reflect water-entry motion. The change laws of the vehicle's attitude and position during the water-entry process are also obtained by analyzing the simulation of the modified model under different velocity, angle, and angle of attack conditions. The results presented here have guiding significance for the future realization of reaching the stable underwater navigation state of the vehicle after water-entry process.

Hyperactivity in boys with attention-deficit/hyperactivity disorder (ADHD): The role of executive and non-executive functions.

PubMed

Hudec, Kristen L; Alderson, R Matt; Patros, Connor H G; Lea, Sarah E; Tarle, Stephanie J; Kasper, Lisa J

2015-01-01

Motor activity of boys (age 8-12 years) with (n=19) and without (n=18) ADHD was objectively measured with actigraphy across experimental conditions that varied with regard to demands on executive functions. Activity exhibited during two n-back (1-back, 2-back) working memory tasks was compared to activity during a choice-reaction time (CRT) task that placed relatively fewer demands on executive processes and during a simple reaction time (SRT) task that required mostly automatic processing with minimal executive demands. Results indicated that children in the ADHD group exhibited greater activity compared to children in the non-ADHD group. Further, both groups exhibited the greatest activity during conditions with high working memory demands, followed by the reaction time and control task conditions, respectively. The findings indicate that large-magnitude increases in motor activity are predominantly associated with increased demands on working memory, though demands on non-executive processes are sufficient to elicit small to moderate increases in motor activity as well. Published by Elsevier Ltd.

Separation of components from a scale mixture of Gaussian white noises

NASA Astrophysics Data System (ADS)

Vamoş, Călin; Crăciun, Maria

2010-05-01

The time evolution of a physical quantity associated with a thermodynamic system whose equilibrium fluctuations are modulated in amplitude by a slowly varying phenomenon can be modeled as the product of a Gaussian white noise {Zt} and a stochastic process with strictly positive values {Vt} referred to as volatility. The probability density function (pdf) of the process Xt=VtZt is a scale mixture of Gaussian white noises expressed as a time average of Gaussian distributions weighted by the pdf of the volatility. The separation of the two components of {Xt} can be achieved by imposing the condition that the absolute values of the estimated white noise be uncorrelated. We apply this method to the time series of the returns of the daily S&P500 index, which has also been analyzed by means of the superstatistics method that imposes the condition that the estimated white noise be Gaussian. The advantage of our method is that this financial time series is processed without partitioning or removal of the extreme events and the estimated white noise becomes almost Gaussian only as result of the uncorrelation condition.

Molecular Dynamics Underlie the Nature of MRI Signals: The NMR Shutter-Speed

NASA Astrophysics Data System (ADS)

Springer, Charles S., Jr.

2007-03-01

Motions of the spin-bearing molecules can have profound effects on the very nature (the exponentiality) of the macroscopic NMR signal. Quantitative mechanistic protocols often involve varying the equilibrium molecular kinetics (usually by temperature change) relative to the ``NMR time-scale'' (SS-1), usually ill-defined as the absolute difference of resonance frequencies [|δφ|] in sites between which spins are exchanged. This holds true for the equilibrium water molecule exchange between tissue compartments and distinct populations. However, in vivo studies must [by regulation] be isothermal, and the tissue ^1H2O MRI signals remain essentially isochronous [δφ = 0]. In NMR, an equilibrium process is manifest in the context of its ``exchange condition.'' It only ``appears'' to be fast or slow by comparison of its actual rate constant with its system ``shutter-speed'' (SS). [A nonzero δφ is the first, but not only, SS: its dimension is reciprocal time.] The process kinetics can be measured only if its NMR condition is varied at least partway between the fast- and slow exchange limits. In an isothermal study with no catalyst, this can be accomplished only by varying the pertinent SS. An MRI contrast reagent (CR) increases the laboratory frame ^1H2O relaxation rate constant, Ri [≡ (Ti)-1; i = 1,2]. For an isochronous exchange process, the SS is the intrinsic |δRi| for the sites. In quantitative dynamic-contrast-enhanced (DCE) studies, analytical pharmacokinetic modeling is accomplished on region-of-interest (ROI) or pixel by pixel ^1H2O signal time-courses following bolus CR injections. Accounting for the equilibrium transendothelial and transcytolemmal water interchange processes (a three-site exchange situation) is crucial for modeling accuracy: the relevant SS values vary during the CR bolus passage. This is so for DCE studies of cancer, multiple sclerosis, and myocardial blood flow variation. It is necessary for the successful discrimination of malignant and benign breast and prostate lesions. One can expect a SS for almost any NMR experiment. This includes diffusion weighted and rotating-frame longitudinal relaxation of in vivo ^1H2O signals. In these latter cases, the pertinent SS can be manipulated solely by adjustment of pulse sequence parameters, leading to completely non-invasive protocols.

The Effects of Phonotactic Probability and Neighborhood Density on Adults' Word Learning in Noisy Conditions

PubMed Central

Storkel, Holly L.; Lee, Jaehoon; Cox, Casey

2016-01-01

Purpose Noisy conditions make auditory processing difficult. This study explores whether noisy conditions influence the effects of phonotactic probability (the likelihood of occurrence of a sound sequence) and neighborhood density (phonological similarity among words) on adults' word learning. Method Fifty-eight adults learned nonwords varying in phonotactic probability and neighborhood density in either an unfavorable (0-dB signal-to-noise ratio [SNR]) or a favorable (+8-dB SNR) listening condition. Word learning was assessed using a picture naming task by scoring the proportion of phonemes named correctly. Results The unfavorable 0-dB SNR condition showed a significant interaction between phonotactic probability and neighborhood density in the absence of main effects. In particular, adults learned more words when phonotactic probability and neighborhood density were both low or both high. The +8-dB SNR condition did not show this interaction. These results are inconsistent with those from a prior adult word learning study conducted under quiet listening conditions that showed main effects of word characteristics. Conclusions As the listening condition worsens, adult word learning benefits from a convergence of phonotactic probability and neighborhood density. Clinical implications are discussed for potential populations who experience difficulty with auditory perception or processing, making them more vulnerable to noise. PMID:27788276

The Effects of Phonotactic Probability and Neighborhood Density on Adults' Word Learning in Noisy Conditions.

PubMed

Han, Min Kyung; Storkel, Holly L; Lee, Jaehoon; Cox, Casey

2016-11-01

Noisy conditions make auditory processing difficult. This study explores whether noisy conditions influence the effects of phonotactic probability (the likelihood of occurrence of a sound sequence) and neighborhood density (phonological similarity among words) on adults' word learning. Fifty-eight adults learned nonwords varying in phonotactic probability and neighborhood density in either an unfavorable (0-dB signal-to-noise ratio [SNR]) or a favorable (+8-dB SNR) listening condition. Word learning was assessed using a picture naming task by scoring the proportion of phonemes named correctly. The unfavorable 0-dB SNR condition showed a significant interaction between phonotactic probability and neighborhood density in the absence of main effects. In particular, adults learned more words when phonotactic probability and neighborhood density were both low or both high. The +8-dB SNR condition did not show this interaction. These results are inconsistent with those from a prior adult word learning study conducted under quiet listening conditions that showed main effects of word characteristics. As the listening condition worsens, adult word learning benefits from a convergence of phonotactic probability and neighborhood density. Clinical implications are discussed for potential populations who experience difficulty with auditory perception or processing, making them more vulnerable to noise.

Use of Field Observations for Understanding Controls of Polar Low Cloud Microphysical Properties

NASA Astrophysics Data System (ADS)

McFarquhar, G. M.

2016-12-01

Although arctic clouds have a net warming effect on the Arctic surface, their radiative effect is sensitive to cloud microphysical properties, namely the sizes, phases and shapes of cloud particles. Such cloud properties are influenced by the numbers, compositions and sizes of aerosols, meteorological conditions, and surface characteristics. Uncertainty in representing cloud-aerosol interactions in varying environmental conditions and associated feedbacks is a major cause in our lack of understanding of why the Arctic is warming faster than the rest of the Earth. Here, the understanding of cloud-aerosol interactions gained from past arctic field experiments is reviewed. Such studies have characterized the structure of single-layer mixed phase clouds that are ubiquitous in the Arctic and investigated different aerosol indirect effect mechanisms acting in these clouds. But, it is still unknown what controls the amount of supercooled water in arctic clouds (especially in complex frequently occurring multi-layer clouds), how probability distributions of cloud properties and radiative heating and their subsequent impact on temperature profiles and underlying snow and sea ice cover vary with aerosol loading and composition in different surface and meteorological conditions, how the composition and concentration of arctic aerosols and cloud microphysical properties vary annually and interannually, and how cloud-aerosol-radiative interactions can be better represented in models with varying temporal and spatial scales. These needs can be addressed in two ways. First, there is a need for comprehensive and routine aircraft, UAV and tethered balloon measurements in the presence of ground, air or space-based remote sensors over a variety of surface and meteorological conditions. Second, planned observational campaigns (the Measurements of Aerosols Radiation and Clouds over the Southern Oceans MARCUS and the Southern Oceans Cloud Radiation Transport Experimental Study SOCRATES) should provide cloud, aerosol, radiative and precipitation observations over the pristine and continually cloudy Southern Oceans that are remote from natural and continental anthropogenic aerosol sources should provide a process-oriented understanding of cloud-aerosol interactions in liquid and ice clouds.

Incipient Fault Detection for Rolling Element Bearings under Varying Speed Conditions.

PubMed

Xue, Lang; Li, Naipeng; Lei, Yaguo; Li, Ningbo

2017-06-20

Varying speed conditions bring a huge challenge to incipient fault detection of rolling element bearings because both the change of speed and faults could lead to the amplitude fluctuation of vibration signals. Effective detection methods need to be developed to eliminate the influence of speed variation. This paper proposes an incipient fault detection method for bearings under varying speed conditions. Firstly, relative residual (RR) features are extracted, which are insensitive to the varying speed conditions and are able to reflect the degradation trend of bearings. Then, a health indicator named selected negative log-likelihood probability (SNLLP) is constructed to fuse a feature set including RR features and non-dimensional features. Finally, based on the constructed SNLLP health indicator, a novel alarm trigger mechanism is designed to detect the incipient fault. The proposed method is demonstrated using vibration signals from bearing tests and industrial wind turbines. The results verify the effectiveness of the proposed method for incipient fault detection of rolling element bearings under varying speed conditions.

Incipient Fault Detection for Rolling Element Bearings under Varying Speed Conditions

PubMed Central

Xue, Lang; Li, Naipeng; Lei, Yaguo; Li, Ningbo

2017-01-01

Varying speed conditions bring a huge challenge to incipient fault detection of rolling element bearings because both the change of speed and faults could lead to the amplitude fluctuation of vibration signals. Effective detection methods need to be developed to eliminate the influence of speed variation. This paper proposes an incipient fault detection method for bearings under varying speed conditions. Firstly, relative residual (RR) features are extracted, which are insensitive to the varying speed conditions and are able to reflect the degradation trend of bearings. Then, a health indicator named selected negative log-likelihood probability (SNLLP) is constructed to fuse a feature set including RR features and non-dimensional features. Finally, based on the constructed SNLLP health indicator, a novel alarm trigger mechanism is designed to detect the incipient fault. The proposed method is demonstrated using vibration signals from bearing tests and industrial wind turbines. The results verify the effectiveness of the proposed method for incipient fault detection of rolling element bearings under varying speed conditions. PMID:28773035

Subcritical Water Technology for Enhanced Extraction of Biochemical Compounds from Chlorella vulgaris

PubMed Central

Awaluddin, S. A.; Thiruvenkadam, Selvakumar; Izhar, Shamsul; Hiroyuki, Yoshida; Danquah, Michael K.; Harun, Razif

2016-01-01

Subcritical water extraction (SWE) technology has been used for the extraction of active compounds from different biomass materials with low process cost, mild operating conditions, short process times, and environmental sustainability. With the limited application of the technology to microalgal biomass, this work investigates parametrically the potential of subcritical water for high-yield extraction of biochemicals such as carbohydrates and proteins from microalgal biomass. The SWE process was optimized using central composite design (CCD) under varying process conditions of temperature (180–374°C), extraction time (1–20 min), biomass particulate size (38–250 μm), and microalgal biomass loading (5–40 wt.%). Chlorella vulgaris used in this study shows high volatile matter (83.5 wt.%) and carbon content (47.11 wt.%), giving advantage as a feedstock for biofuel production. The results showed maximum total carbohydrate content and protein yields of 14.2 g/100 g and 31.2 g/100 g, respectively, achieved under the process conditions of 277°C, 5% of microalgal biomass loading, and 5 min extraction time. Statistical analysis revealed that, of all the parameters investigated, temperature is the most critical during SWE of microalgal biomass for protein and carbohydrate production. PMID:27366748

Methods of synthesizing hydroxyapatite powders and bulk materials

DOEpatents

Luo, Ping

1999-01-12

Methods are provided for producing non-porous controlled morphology hydroxyapatite granules of less than 8 .mu.m by a spray-drying process. Solid or hollow spheres or doughnuts can be formed by controlling the volume fraction and viscosity of the slurry as well as the spray-drying conditions. Methods of providing for homogenous cellular structure hydroxyapatite granules are also provided. Pores or channels or varying size and number can be formed by varying the temperature at which a hydroxyapatite slurry formed in basic, saturated ammonium hydroxide is spray-dried. Methods of providing non-porous controlled morphology hydroxyapatite granules in ammonium hydroxide are also provided. The hydroxyapatite granules and bulk materials formed by these methods are also provided.

Methods of synthesizing hydroxyapatite powders and bulk materials

DOEpatents

Luo, P.

1999-01-12

Methods are provided for producing non-porous controlled morphology hydroxyapatite granules of less than 8 {micro}m by a spray-drying process. Solid or hollow spheres or doughnuts can be formed by controlling the volume fraction and viscosity of the slurry as well as the spray-drying conditions. Methods of providing for homogeneous cellular structure hydroxyapatite granules are also provided. Pores or channels or varying size and number can be formed by varying the temperature at which a hydroxyapatite slurry formed in basic, saturated ammonium hydroxide is spray-dried. Methods of providing non-porous controlled morphology hydroxyapatite granules in ammonium hydroxide are also provided. The hydroxyapatite granules and bulk materials formed by these methods are also provided. 26 figs.

Sampled-data H∞ filtering for Markovian jump singularly perturbed systems with time-varying delay and missing measurements

NASA Astrophysics Data System (ADS)

Yan, Yifang; Yang, Chunyu; Ma, Xiaoping; Zhou, Linna

2018-02-01

In this paper, sampled-data H∞ filtering problem is considered for Markovian jump singularly perturbed systems with time-varying delay and missing measurements. The sampled-data system is represented by a time-delay system, and the missing measurement phenomenon is described by an independent Bernoulli random process. By constructing an ɛ-dependent stochastic Lyapunov-Krasovskii functional, delay-dependent sufficient conditions are derived such that the filter error system satisfies the prescribed H∞ performance for all possible missing measurements. Then, an H∞ filter design method is proposed in terms of linear matrix inequalities. Finally, numerical examples are given to illustrate the feasibility and advantages of the obtained results.

Temperature and Pressure Dependence of Signal Amplitudes for Electrostriction Laser-Induced Thermal Acoustics

NASA Technical Reports Server (NTRS)

Herring, Gregory C.

2015-01-01

The relative signal strength of electrostriction-only (no thermal grating) laser-induced thermal acoustics (LITA) in gas-phase air is reported as a function of temperature T and pressure P. Measurements were made in the free stream of a variable Mach number supersonic wind tunnel, where T and P are varied simultaneously as Mach number is varied. Using optical heterodyning, the measured signal amplitude (related to the optical reflectivity of the acoustic grating) was averaged for each of 11 flow conditions and compared to the expected theoretical dependence of a pure-electrostriction LITA process, where the signal is proportional to the square root of [P*P /( T*T*T)].

Soft Costs Fact Sheet

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

None

2016-05-01

This fact sheet is an overview of the systems integration subprogram at the U.S. Department of Energy SunShot Initiative. Soft costs can vary significantly as a result of a fragmented energy marketplace. In the U.S., there are 18,000 jurisdictions and 3,000 utilities with different rules and regulations for how to go solar. The same solar equipment may vary widely in its final installation price due to process and market variations across jurisdictions, creating barriers to rapid industry growth. SunShot supports the development of innovative solutions that enable communities to build their local economies and establish clean energy initiatives that meetmore » their needs, while at the same time creating sustainable solar market conditions.« less

Environmental Effects on Mesozooplankton Size Structure and Export Flux at Station ALOHA, North Pacific Subtropical Gyre

NASA Astrophysics Data System (ADS)

Valencia, Bellineth; Décima, Moira; Landry, Michael R.

2018-02-01

Using size-fractionated mesozooplankton biomass data collected over 23 years (1994-2016) of increasing primary production (PP) at station ALOHA (A Long-Term Oligotrophic Habitat Assessment), we evaluate how changing environmental conditions affect mesozooplankton size structure, trophic cycling, and export fluxes in the subtropical North Pacific. From generalized additive model analysis, size structure is significantly influenced by a nonlinear relationship with sea surface temperature that is mainly driven by the strong 1997-1998 El Niño and a positive and linear relationship with PP. Increasing PP has more strongly enhanced the biomass of smaller (0.2-0.5 mm) and larger (>5 mm) mesozooplankton, increasing evenness of the biomass spectra, while animals of 2-5 mm, the major size class for vertically migrating mesozooplankton, show no long-term trend. Measured PP is sufficient to meet feeding requirements that satisfy mesozooplankton respiration and growth rates, as determined by commonly used empirical relationships based on animal size and temperature, consistent with a tightly coupled food web with one intermediate level for protistan consumers. Estimated fecal pellet production suggests an enhanced contribution of mesozooplankton to passive particle export relative to the material collected in 150 m sediment traps. In contrast, the biomass of vertically migrants does not vary systematically with PP due to the varying responses of the different size classes. These results illustrate some complexities in understanding how varying environmental conditions can affect carbon cycling and export processes at the community level in open-ocean oligotrophic systems, which need to be confirmed and better understood by process-oriented mechanistic study.

Solar Cycle Effects on Equatorial Electrojet Strength and Low Latitude Ionospheric Variability (P10)

NASA Astrophysics Data System (ADS)

Veenadhari, B.; Alex, S.

2006-11-01

veena_iig@yahoo.co.in The most obvious indicators of the activity of a solar cycle are sunspots, flares, plages, and soon. These are intimately linked to the solar magnetic fields, heliospheric processes which exhibit complex but systematic variations. The changes in geomagnetic activity, as observed in the ground magnetic records follow systematic correspondence with the solar activity conditions. Thus the transient variations in the magnetic field get modified by differing solar conditions. Also the solar cycle influences the Earth causing changes in geomagnetic activity, the magnetosphere and the ionosphere. Daily variations in the ground magnetic field are produced by different current systems in the earth’s space environment flowing in the ionosphere and magnetosphere which has a strong dependence on latitude and longitude of the location. The north-south (Horizontal) configuration of the earth’s magnetic field over the equator is responsible for the narrow band of current system over the equatorial latitudes and is called the Equatorial electrojet (EEJ) and is a primary driver for Equatorial Ionization anomaly (EIA). Equatorial electric fields and plasma drifts play the fundamental roles on the morphology of the low latitude ionosphere and strongly vary during geomagnetically quiet and disturbed periods. Quantitative study is done to illustrate the development process of EEJ and its influence on ionospheric parameters. An attempt is also made to examine and discuss the response of the equatorial electrojet parameters to the fast varying conditions of solar wind and interplanetary parameters.

A Methodology for Soil Moisture Retrieval from Land Surface Temperature, Vegetation Index, Topography and Soil Type

NASA Astrophysics Data System (ADS)

Pradhan, N. R.

2015-12-01

Soil moisture conditions have an impact upon hydrological processes, biological and biogeochemical processes, eco-hydrology, floods and droughts due to changing climate, near-surface atmospheric conditions and the partition of incoming solar and long-wave radiation between sensible and latent heat fluxes. Hence, soil moisture conditions virtually effect on all aspects of engineering / military engineering activities such as operational mobility, detection of landmines and unexploded ordinance, natural material penetration/excavation, peaking factor analysis in dam design etc. Like other natural systems, soil moisture pattern can vary from completely disorganized (disordered, random) to highly organized. To understand this varying soil moisture pattern, this research utilized topographic wetness index from digital elevation models (DEM) along with vegetation index from remotely sensed measurements in red and near-infrared bands, as well as land surface temperature (LST) in the thermal infrared bands. This research developed a methodology to relate a combined index from DEM, LST and vegetation index with the physical soil moisture properties of soil types and the degree of saturation. The advantage in using this relationship is twofold: first it retrieves soil moisture content at the scale of soil data resolution even though the derived indexes are in a coarse resolution, and secondly the derived soil moisture distribution represents both organized and disorganized patterns of actual soil moisture. The derived soil moisture is used in driving the hydrological model simulations of runoff, sediment and nutrients.

Effects of music engagement on responses to painful stimulation.

PubMed

Bradshaw, David H; Chapman, C Richard; Jacobson, Robert C; Donaldson, Gary W

2012-06-01

We propose a theoretical framework for the behavioral modulation of pain based on constructivism, positing that task engagement, such as listening for errors in a musical passage, can establish a construction of reality that effectively replaces pain as a competing construction. Graded engagement produces graded reductions in pain as indicated by reduced psychophysiological arousal and subjective pain report. Fifty-three healthy volunteers having normal hearing participated in 4 music listening conditions consisting of passive listening (no task) or performing an error detection task varying in signal complexity and task difficulty. During all conditions, participants received normally painful fingertip shocks varying in intensity while stimulus-evoked potentials (SEP), pupil dilation responses (PDR), and retrospective pain reports were obtained. SEP and PDR increased with increasing stimulus intensity. Task performance decreased with increasing task difficulty. Mixed model analyses, adjusted for habituation/sensitization and repeated measures within person, revealed significant quadratic trends for SEP and pain report (Pchange<0.001) with large reductions from no task to easy task and smaller graded reductions corresponding to increasing task difficulty/complexity. PDR decreased linearly (Pchange<0.001) with graded task condition. We infer that these graded reductions in indicators of central and peripheral arousal and in reported pain correspond to graded increases in engagement in the music listening task. Engaging activities may prevent pain by creating competing constructions of reality that draw on the same processing resources as pain. Better understanding of these processes will advance the development of more effective pain modulation through improved manipulation of engagement strategies.

Experimental quantum verification in the presence of temporally correlated noise

NASA Astrophysics Data System (ADS)

Mavadia, S.; Edmunds, C. L.; Hempel, C.; Ball, H.; Roy, F.; Stace, T. M.; Biercuk, M. J.

2018-02-01

Growth in the capabilities of quantum information hardware mandates access to techniques for performance verification that function under realistic laboratory conditions. Here we experimentally characterise the impact of common temporally correlated noise processes on both randomised benchmarking (RB) and gate-set tomography (GST). Our analysis highlights the role of sequence structure in enhancing or suppressing the sensitivity of quantum verification protocols to either slowly or rapidly varying noise, which we treat in the limiting cases of quasi-DC miscalibration and white noise power spectra. We perform experiments with a single trapped 171Yb+ ion-qubit and inject engineered noise (" separators="∝σ^ z ) to probe protocol performance. Experiments on RB validate predictions that measured fidelities over sequences are described by a gamma distribution varying between approximately Gaussian, and a broad, highly skewed distribution for rapidly and slowly varying noise, respectively. Similarly we find a strong gate set dependence of default experimental GST procedures in the presence of correlated errors, leading to significant deviations between estimated and calculated diamond distances in the presence of correlated σ^ z errors. Numerical simulations demonstrate that expansion of the gate set to include negative rotations can suppress these discrepancies and increase reported diamond distances by orders of magnitude for the same error processes. Similar effects do not occur for correlated σ^ x or σ^ y errors or depolarising noise processes, highlighting the impact of the critical interplay of selected gate set and the gauge optimisation process on the meaning of the reported diamond norm in correlated noise environments.

Emotional self-reference: brain structures involved in the processing of words describing one's own emotions.

PubMed

Herbert, Cornelia; Herbert, Beate M; Pauli, Paul

2011-08-01

The present functional magnetic resonance imaging study investigated the role of emotion-related (e.g., amygdala) and self-related brain structures (MPFC in particular) in the processing of emotional words varying in stimulus reference. Healthy subjects (N=22) were presented with emotional (pleasant or unpleasant) or neutral words in three different conditions: (1) self (e.g., my fear), (2) other (e.g., his fear) and (3) no reference (e.g., the fear). Processing of unpleasant words was associated with increased amygdala and also insula activation across all conditions. Pleasant stimuli were specifically associated with increased activation of amygdala and insula when related to the self (vs. other and no reference). Activity in the MPFC (vMPFC in particular) and anterior cingulate cortex (ACC) was preferentially increased during processing of self-related emotional words (vs. other and no reference). These results demonstrate that amygdala activation in response to emotional stimuli is modulated by stimulus reference and that brain structures implicated in emotional and self-related processing might be important for the subjective experience of one's own emotions. Copyright © 2011 Elsevier Ltd. All rights reserved.

The behavior of fuel-lean premixed flames in a standard flammability limit tube under controlled gravity conditions

NASA Technical Reports Server (NTRS)

Wherley, B. L.; Strehlow, R. A.

1986-01-01

Fuel-lean flames in methane-air mixtures from 4.90 to 6.20 volume percent fuel and propane-air mixtures from 1.90 to 3.00 volume percent fuel were studied in the vicinity of the limit for a variety of gravity conditions. The limits were determined and the behavior of the flames studied for one g upward, one g downward, and zero g propagation. Photographic records of all flammability tube firings were obtained. The structure and behavior of these flames were detailed including the variations of the curvature of the flame front, the skirt length, and the occurrence of cellular instabilities with varying gravity conditions. The effect of ignition was also discussed. A survey of flame speeds as a function of mixture strength was made over a range of lean mixture compositions for each of the fuels studied. The results were presented graphically with those obtained by other researchers. The flame speed for constant fractional gravity loadings were plotted as a function of gravity loadings from 0.0 up to 2.0 g's against flame speeds extracted from the transient gravity flame histories for corresponding gravity loadings. The effects of varying gravity conditions on the extinguishment process for upward and downward propagating flames were investigated.

CO line ratios in molecular clouds: the impact of environment

NASA Astrophysics Data System (ADS)

Peñaloza, Camilo H.; Clark, Paul C.; Glover, Simon C. O.; Klessen, Ralf S.

2018-04-01

Line emission is strongly dependent on the local environmental conditions in which the emitting tracers reside. In this work, we focus on modelling the CO emission from simulated giant molecular clouds (GMCs), and study the variations in the resulting line ratios arising from the emission from the J = 1-0, J = 2-1, and J = 3-2 transitions. We perform a set of smoothed particle hydrodynamics simulations with time-dependent chemistry, in which environmental conditions - including total cloud mass, density, size, velocity dispersion, metallicity, interstellar radiation field (ISRF), and the cosmic ray ionization rate (CRIR) - were systematically varied. The simulations were then post-processed using radiative transfer to produce synthetic emission maps in the three transitions quoted above. We find that the cloud-averaged values of the line ratios can vary by up to ±0.3 dex, triggered by changes in the environmental conditions. Changes in the ISRF and/or in the CRIR have the largest impact on line ratios since they directly affect the abundance, temperature, and distribution of CO-rich gas within the clouds. We show that the standard methods used to convert CO emission to H2 column density can underestimate the total H2 molecular gas in GMCs by factors of 2 or 3, depending on the environmental conditions in the clouds.

Scavenging Rate Ecoassay: A Potential Indicator of Estuary Condition

PubMed Central

Porter, Augustine G.; Scanes, Peter R.

2015-01-01

Monitoring of estuary condition is essential due to the highly productive and often intensely impacted nature of these ecosystems. Assessment of the physico-chemical condition of estuaries is expensive and difficult due to naturally fluctuating water quality and biota. Assessing the vigour of ecosystem processes is an alternative method with potential to overcome much of the variability associated with physico-chemical measures. Indicators of estuary condition should have small spatial and temporal variability, have a predictable response to perturbation and be ecologically relevant. Here, we present tests of the first criterion, the spatio-temporal variability of a potential ecoassay measuring the rate of scavenging in estuaries. We hypothesised that the proposed scavenging ecoassay would not vary significantly among A) sites in an estuary, B) trips separated by weeks, or C) days in a trip. Because not all habitats are present in all estuaries, this test was undertaken in two habitats. When conducted over bare substrate there were occasional significant differences, but no discernible patterns, within levels of the experiment. When conducted over vegetated substrate, days within a trip did not vary significantly, but later trips experienced greater scavenging. This scavenging ecoassay shows potential as a tool for assessing the condition of estuarine ecosystems, and further exploration of this protocol is warranted by implementation in estuaries across a gradient of anthropogenic stress. PMID:26024225

Evaporation from soils subjected to natural boundary conditions at the land-atmospheric interface

NASA Astrophysics Data System (ADS)

Smits, K.; Illngasekare, T.; Ngo, V.; Cihan, A.

2012-04-01

Bare soil evaporation is a key process for water exchange between the land and the atmosphere and an important component of the water balance in semiarid and arid regions. However, there is no agreement on the best methodology to determine evaporation under different boundary conditions at the land surface. This becomes critical in developing models that couples land to the atmosphere. Because it is difficult to measure evaporation from soil, with the exception of using lysimeters, numerous formulations have been proposed to establish a relationship between the rate of evaporation and soil moisture and/or soil temperature and thermal properties. Different formulations vary in how they partition available energy. A need exists to systematically compare existing methods to experimental data under highly controlled conditions not achievable in the field. The goal of this work is to perform controlled experiments under transient conditions of soil moisture, temperature and wind at the land/atmospheric interface to test different conceptual and mathematical formulations for the soil surface boundary conditions to develop appropriate numerical models to be used in simulations. In this study, to better understand the coupled water-vapor-heat flow processes in the shallow subsurface near the land surface, we modified a previously developed theory by Smits et al. [2011] that allows non-equilibrium liquid/gas phase change with gas phase vapor diffusion to better account for dry soil conditions. The model did not implement fitting parameters such as a vapor enhancement factor that is commonly introduced into the vapor diffusion coefficient as an arbitrary multiplication factor. In order to experimentally test the numerical formulations/code, we performed a two-dimensional physical model experiment under varying boundary conditions using test sand for which the hydraulic and thermal properties were well characterized. Precision data under well-controlled transient heat and wind boundary conditions was generated and results from numerical simulations were compared with experimental data. Results demonstrate that the boundary condition approaches varied in their ability to capture stage 1- and stage 2- evaporation. Results also demonstrated the importance of properly characterizing soil thermal properties and accounting for dry soil conditions. The contribution of film flow to hydraulic conductivity for the layer above the drying front is dominant compared to that of capillary flow, demonstrating the importance of including film flow in modeling efforts for dry soils, especially for fine grained soils. Comparisons of different formulations of the surface boundary condition validate the need for joint evaluation of heat and mass transfer for better modeling accuracy. This knowledge is applicable to many current hydrologic and environmental problems to include climate modeling and the simulation of contaminant transport and volatilization in the shallow subsurface. Smits, K. M., A. Cihan, T. Sakaki, and T. H. Illangasekare (2011). Evaporation from soils under thermal boundary conditions: Experimental and modeling investigation to compare equilibrium- and nonequilibrium-based approaches, Water Resour. Res., 47, W05540, doi:10.1029/2010WR009533.

Application of a simplified mathematical model to estimate the effect of forced aeration on composting in a closed system.

PubMed

Bari, Quazi H; Koenig, Albert

2012-11-01

The aeration rate is a key process control parameter in the forced aeration composting process because it greatly affects different physico-chemical parameters such as temperature and moisture content, and indirectly influences the biological degradation rate. In this study, the effect of a constant airflow rate on vertical temperature distribution and organic waste degradation in the composting mass is analyzed using a previously developed mathematical model of the composting process. The model was applied to analyze the effect of two different ambient conditions, namely, hot and cold ambient condition, and four different airflow rates such as 1.5, 3.0, 4.5, and 6.0 m(3) m(-2) h(-1), respectively, on the temperature distribution and organic waste degradation in a given waste mixture. The typical waste mixture had 59% moisture content and 96% volatile solids, however, the proportion could be varied as required. The results suggested that the model could be efficiently used to analyze composting under variable ambient and operating conditions. A lower airflow rate around 1.5-3.0 m(3) m(-2) h(-1) was found to be suitable for cold ambient condition while a higher airflow rate around 4.5-6.0 m(3) m(-2) h(-1) was preferable for hot ambient condition. The engineered way of application of this model is flexible which allows the changes in any input parameters within the realistic range. It can be widely used for conceptual process design, studies on the effect of ambient conditions, optimization studies in existing composting plants, and process control. Copyright © 2012 Elsevier Ltd. All rights reserved.

The effects of quantity and depth of processing on children's time perception.

PubMed

Arlin, M

1986-08-01

Two experiments were conducted to investigate the effects of quantity and depth of processing on children's time perception. These experiments tested the appropriateness of two adult time-perception models (attentional and storage size) for younger ages. Children were given stimulus sets of equal time which varied by level of processing (deep/shallow) and quantity (list length). In the first experiment, 28 children in Grade 6 reproduced presentation times of various quantities of pictures under deep (living/nonliving categorization) or shallow (repeating label) conditions. Students also compared pairs of durations. In the second experiment, 128 children in Grades K, 2, 4, and 6 reproduced presentation times under similar conditions with three or six pictures and with deep or shallow processing requirements. Deep processing led to decreased estimation of time. Higher quantity led to increased estimation of time. Comparative judgments were influenced by quantity. The interaction between age and depth of processing was significant. Older children were more affected by depth differences than were younger children. Results were interpreted as supporting different aspects of each adult model as explanations of children's time perception. The processing effect supported the attentional model and the quantity effect supported the storage size model.

An Improved Gaussian Mixture Model for Damage Propagation Monitoring of an Aircraft Wing Spar under Changing Structural Boundary Conditions.

PubMed

Qiu, Lei; Yuan, Shenfang; Mei, Hanfei; Fang, Fang

2016-02-26

Structural Health Monitoring (SHM) technology is considered to be a key technology to reduce the maintenance cost and meanwhile ensure the operational safety of aircraft structures. It has gradually developed from theoretic and fundamental research to real-world engineering applications in recent decades. The problem of reliable damage monitoring under time-varying conditions is a main issue for the aerospace engineering applications of SHM technology. Among the existing SHM methods, Guided Wave (GW) and piezoelectric sensor-based SHM technique is a promising method due to its high damage sensitivity and long monitoring range. Nevertheless the reliability problem should be addressed. Several methods including environmental parameter compensation, baseline signal dependency reduction and data normalization, have been well studied but limitations remain. This paper proposes a damage propagation monitoring method based on an improved Gaussian Mixture Model (GMM). It can be used on-line without any structural mechanical model and a priori knowledge of damage and time-varying conditions. With this method, a baseline GMM is constructed first based on the GW features obtained under time-varying conditions when the structure under monitoring is in the healthy state. When a new GW feature is obtained during the on-line damage monitoring process, the GMM can be updated by an adaptive migration mechanism including dynamic learning and Gaussian components split-merge. The mixture probability distribution structure of the GMM and the number of Gaussian components can be optimized adaptively. Then an on-line GMM can be obtained. Finally, a best match based Kullback-Leibler (KL) divergence is studied to measure the migration degree between the baseline GMM and the on-line GMM to reveal the weak cumulative changes of the damage propagation mixed in the time-varying influence. A wing spar of an aircraft is used to validate the proposed method. The results indicate that the crack propagation under changing structural boundary conditions can be monitored reliably. The method is not limited by the properties of the structure, and thus it is feasible to be applied to composite structure.

Quantifying Construction Site Sediment Discharge Risk and Treatment Potential

NASA Astrophysics Data System (ADS)

Ferrell, L.; Beighley, R. E.

2006-12-01

Dealing with soil erosion and sediment transport can be a significant challenge during the construction process due to the potentially large spatial and temporal extent and conditions of bare soils. Best Management Practices (BMP) are commonly used to eliminate or reduce offsite discharge of sediment. However, few efforts have investigated the time varying risk of sediment discharge from construction sites, which often have dynamic soil conditions and the potential for less than optimal BMP installations. The goal of this research is to improve the design, implementation and effectiveness of sediment and erosion control at construction sites using site specific, temporal distributions of sediment discharge risk. Sediment risk is determined from individual factors leading to sediment expert, such as rainfall frequency, the adequacy of BMP installations, and the extent and duration of bare soil conditions. This research specifically focuses on quantifying: (a) the effectiveness of temporary sediment and control erosion control BMPs in preventing, containing, and/or treating construction site sediment discharge at varying levels of "proper" installation, and (b) sediment discharge potential from construction sites during different phases of construction, (ex., disturbed earth operations). BMPs are evaluated at selected construction sites in southern California and at the Soil Erosion Research Laboratory (SERL) in the Civil and Environmental Engineering department at San Diego State University. SERL experiments are performed on a 3-m by 10-m tilting soil bed with soil depths up to 1 meter, slopes ranging from 0 to 50 percent, and rainfall rates up to 150 mm/hr (6 in/hr). BMP performance is assessed based on experiments where BMPs are installed per manufacture specifications, potential less than optimal installations, and no treatment conditions. Soil conditions are also varied to represent site conditions during different phases of construction (i.e., loose lifts, stock piles, temporary roads, finished grade, others). Preliminary site monitoring, experimental results, and a conceptual model for estimating the time depend risk of sediment discharge over the duration of a construction project are presented.

Some Considerations Relating to Combustion in Rocket Motors

DTIC Science & Technology

1950-03-01

evaporation and chemical reaction. Even the separate processes of heat and mass transfer under varying conditions are too complex for adequate theoretical...treatment although with the aid of dimensional analysis and experiment useful relationships for the heat transfer to spheres and for the evaporation of...if they do not evaporate sufficiently rapidly they may be carriod out of the rocket in the gas stream with a consequent loss in performance. 4

Effects of Short-Term Biosolarization Using Mature Compost and Industrial Tomato Waste Amendments on the Generation and Persistence of Biocidal Soil Conditions and Subsequent Tomato Growth.

PubMed

Achmon, Yigal; Sade, Nir; Wilhelmi, María Del Mar Rubio; Fernández-Bayo, Jesus D; Harrold, Duff R; Stapleton, James J; VanderGheynst, Jean S; Blumwald, Eduardo; Simmons, Christopher W

2018-06-06

Conventional solarization and biosolarization with mature compost and tomato processing residue amendments were compared with respect to generation of pesticidal conditions and tomato ( Solanum lycopersicum L.) plant growth in treated soils. Soil oxygen depletion was examined as a response that has previously not been measured across multiple depths during biosolarization. For biosolarized soil, volatile fatty acids were found to accumulate concurrent with oxygen depletion, and the magnitude of these changes varied by soil depth. Two consecutive years of experimentation showed varying dissipation of volatile fatty acids from biosolarized soils post-treatment. When residual volatile fatty acids were detected in the biosolarized soil, fruit yield did not significantly differ from plants grown in solarized soil. However, when there was no residual volatile fatty acids in the soil at the time of planting, plants grown in biosolarized soil showed a significantly greater vegetation amount, fruit quantity, and fruit ripening than those of plants grown in solarized soil.

Modeling Storm-Influenced Suspended Particulate Matter Flocculation Using a Tide-Wave-Combined Biomineral Model.

PubMed

Chen, Peihung; Yu, Jason C S; Fettweis, Michael

2018-03-01

  Flocculation of suspended particulate matter (SPM) in marine and estuarine environments is a complex process that is influenced by physical, biological, and chemical mechanisms. The flocculation model of Maggi (2009) was adapted to simulate flocculation under various weather conditions and during different seasons. The adaptation incorporated the effect of tide-wave-combined turbulence on floc dynamics. The model was validated using in situ measurements of floc size and SPM concentration from the southern North Sea during both calm and storm conditions. The results show that tide-wave-combined turbulence needs to be incorporated when simulating flocculation in a tide-wave-dominated environment. The observed seasonal variations in floc size (Fettweis et al., 2014) were reproduced using varying values for various floc strengths in different seasons. The results revealed that the biological effect on floc strength, which enhances aggregation, is stronger during summer, indicating that floc strength in the model should be varied seasonally.

Gratitude intervention modulates P3 amplitude in a temporal discounting task.

PubMed

Patalano, Andrea L; Lolli, Sydney L; Sanislow, Charles A

2018-06-23

Gratitude has been shown to reduce economic impatience. In particular, individuals induced to experience heightened gratitude are more willing to choose delayed larger rewards over immediate smaller rewards (i.e., they have lower discounting rates) than those in a neutral condition. Using the event-related potential (ERP) method, we investigated the relation between gratitude level and neurophysiological correlates. Of interest was motivated information processing, as indexed by the P3 component. Participants were administered a gratitude or a neutral mood induction followed by a temporal discounting task (choosing between a fixed immediate reward versus a future reward that varied across trials) while electroencephalogram (EEG) activity was recorded. Individuals in the gratitude condition had greater P3 amplitude, suggesting greater attention to the future-reward option (the choice option that varied across trials), even when this option was not selected, and providing the first evidence of gratitude-induced changes in electrophysiological activity. Copyright © 2018. Published by Elsevier B.V.

Tribological Behavior of Electroless Ni-P Coatings in Various Corrosive Environments

NASA Astrophysics Data System (ADS)

Panja, Bikash; Das, Suman Kalyan; Sahoo, Prasanta

2016-04-01

The present paper deals with the study of tribological characteristics, viz. friction and wear, of electroless Ni-P coating in corrosive environments (brine, acidic and alkaline) by varying different coating process parameters as well as varying the tribological testing parameters, viz. applied load and speed. The optimized results of coating process parameters for minimum friction and wear performance of the coating are presented. Moreover, a detailed study of the tribological behavior of the coating is undertaken individually for the three corrosive environments. The results obtained are compared among each other and also with the dry condition test of the coating. It is found that the friction coefficient of Ni-P coating decreases with increase in load for all environments. In case of wear, the wear rate of Ni-P coating gradually increases with increase in load for all mediums but the same decreases after 40N in brine and alkaline mediums. However, for acidic solution, the wear rate shows a continuous increasing trend. It is observed that alkaline and brine environments are favorable from friction and wear point of view of the coating, respectively. Microstructure study of the coatings is also performed and the coating is found to be of cauliflower-like morphology. The coating also exhibits amorphous structure in as-deposited condition, which gradually turns crystalline with heat treatment.

Quality and loudness judgments for music subjected to compression limiting.

PubMed

Croghan, Naomi B H; Arehart, Kathryn H; Kates, James M

2012-08-01

Dynamic-range compression (DRC) is used in the music industry to maximize loudness. The amount of compression applied to commercial recordings has increased over time due to a motivating perspective that louder music is always preferred. In contrast to this viewpoint, artists and consumers have argued that using large amounts of DRC negatively affects the quality of music. However, little research evidence has supported the claims of either position. The present study investigated how DRC affects the perceived loudness and sound quality of recorded music. Rock and classical music samples were peak-normalized and then processed using different amounts of DRC. Normal-hearing listeners rated the processed and unprocessed samples on overall loudness, dynamic range, pleasantness, and preference, using a scaled paired-comparison procedure in two conditions: un-equalized, in which the loudness of the music samples varied, and loudness-equalized, in which loudness differences were minimized. Results indicated that a small amount of compression was preferred in the un-equalized condition, but the highest levels of compression were generally detrimental to quality, whether loudness was equalized or varied. These findings are contrary to the "louder is better" mentality in the music industry and suggest that more conservative use of DRC may be preferred for commercial music.

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

Martinez-Guerra, Edith; Gude, Veera Gnaneswar, E-mail: gude@cee.msstate.edu

Highlights: • Pulse sonication effect on transesterification of waste vegetable oil was studied. • Effects of ethanol, methanol, and alcohol mixtures on FAMEs yield were evaluated. • Effect of ultrasonic intensity, power density, and its output rates were evaluated. • Alcohol mixtures resulted in higher biodiesel yields due to better solubility. - Abstract: This study reports on the effects of direct pulse sonication and the type of alcohol (methanol and ethanol) on the transesterification reaction of waste vegetable oil without any external heating or mechanical mixing. Biodiesel yields and optimum process conditions for the transesterification reaction involving ethanol, methanol, andmore » ethanol–methanol mixtures were evaluated. The effects of ultrasonic power densities (by varying sample volumes), power output rates (in W), and ultrasonic intensities (by varying the reactor size) were studied for transesterification reaction with ethanol, methanol and ethanol–methanol (50%-50%) mixtures. The optimum process conditions for ethanol or methanol based transesterification reaction of waste vegetable oil were determined as: 9:1 alcohol to oil ratio, 1% wt. catalyst amount, 1–2 min reaction time at a power output rate between 75 and 150 W. It was shown that the transesterification reactions using ethanol–methanol mixtures resulted in biodiesel yields as high as >99% at lower power density and ultrasound intensity when compared to ethanol or methanol based transesterification reactions.« less

Distinguishing synchronous and time-varying synergies using point process interval statistics: motor primitives in frog and rat

PubMed Central

Hart, Corey B.; Giszter, Simon F.

2013-01-01

We present and apply a method that uses point process statistics to discriminate the forms of synergies in motor pattern data, prior to explicit synergy extraction. The method uses electromyogram (EMG) pulse peak timing or onset timing. Peak timing is preferable in complex patterns where pulse onsets may be overlapping. An interval statistic derived from the point processes of EMG peak timings distinguishes time-varying synergies from synchronous synergies (SS). Model data shows that the statistic is robust for most conditions. Its application to both frog hindlimb EMG and rat locomotion hindlimb EMG show data from these preparations is clearly most consistent with synchronous synergy models (p < 0.001). Additional direct tests of pulse and interval relations in frog data further bolster the support for synchronous synergy mechanisms in these data. Our method and analyses support separated control of rhythm and pattern of motor primitives, with the low level execution primitives comprising pulsed SS in both frog and rat, and both episodic and rhythmic behaviors. PMID:23675341

Process optimization involving critical evaluation of oxygen transfer, oxygen uptake and nitrogen limitation for enhanced biomass and lipid production by oleaginous yeast for biofuel application.

PubMed

Chopra, Jayita; Sen, Ramkrishna

2018-04-20

Lipid accumulation in oleaginous yeast is generally induced by nitrogen starvation, while oxygen saturation can influence biomass growth. Systematic shake flask studies that help in identifying the right nitrogen source and relate its uptake kinetics to lipid biosynthesis under varying oxygen saturation conditions are very essential for addressing the bioprocessing-related issues, which are envisaged to occur in the fermenter scale production. In the present study, lipid bioaccumulation by P. guilliermondii at varying C:N ratios and oxygen transfer conditions (assessed in terms of k L a) was investigated in shake flasks using a pre-optimized N-source and a two-stage inoculum formulated in a hybrid medium. A maximum lipid concentration of 10.8 ± 0.5 g L -1 was obtained in shake flask study at the optimal condition with an initial C:N and k L a of 60:1 and 0.6 min -1 , respectively, at a biomass specific growth rate of 0.11 h -1 . Translating these optimal shake flask conditions to a 3.7 L stirred tank reactor resulted in biomass and lipid concentrations of 16.74 ± 0.8 and 8 ± 0.4 g L -1 . The fatty acid methyl ester (FAME) profile of lipids obtained by gas chromatography was found to be suitable for biodiesel application. We strongly believe that the rationalistic approach-based design of experiments adopted in the study would help in achieving high cell density with improved lipid accumulation and also minimize the efforts towards process optimization during bioreactor level operations, consequently reducing the research and development-associated costs.

Application of fuzzy logic to the control of wind tunnel settling chamber temperature

NASA Technical Reports Server (NTRS)

Gwaltney, David A.; Humphreys, Gregory L.

1994-01-01

The application of Fuzzy Logic Controllers (FLC's) to the control of nonlinear processes, typically controlled by a human operator, is a topic of much study. Recent application of a microprocessor-based FLC to the control of temperature processes in several wind tunnels has proven to be very successful. The control of temperature processes in the wind tunnels requires the ability to monitor temperature feedback from several points and to accommodate varying operating conditions in the wind tunnels. The FLC has an intuitive and easily configurable structure which incorporates the flexibility required to have such an ability. The design and implementation of the FLC is presented along with process data from the wind tunnels under automatic control.

Opposing effects of perceptual versus working memory load on emotional distraction.

PubMed

Tavares, Tamara P; Logie, Kyle; Mitchell, Derek G V

2016-10-01

Throughout our day-to-day activities, we are subjected to numerous stimuli that compete for our attention; consequently, we must prioritize stimuli for further processing and influence over behaviour. Previous research has demonstrated that the extent to which task-irrelevant distractors are processed is mediated by the nature of the cognitive task, and the level of processing load. Importantly though, the interaction between cognitive task, processing load, and emotional distractor processing remains unclear. This is a particularly important question given the unique ways that emotion interacts with attention, and the fact that some other forms of processing load have been shown to reduce emotional distractor encoding. In the present study, participants were presented with emotional distractors during a perceptual and working memory task, under varying levels of load. In Experiment 1, we showed that the impact of emotional distractors on behaviour was reduced under conditions of high relative to low perceptual load. However, in sharp contrast, high working memory load was associated with increased emotional distraction. Importantly, these results were replicated in Experiment 2. Overall, the impact of processing load on emotional distraction varies according to the cognitive function being performed. These results raise the intriguing possibility that working memory operations deplete some of the cognitive resources needed to control the impact of emotion on behaviour. The findings, therefore, may have important implications for clinical populations featuring cognitive dysfunction and emotional dysregulation.

Risk analysis and detection of thrombosis by measurement of electrical resistivity of blood.

PubMed

Sapkota, Achyut; Asakura, Yuta; Maruyama, Osamu; Kosaka, Ryo; Yamane, Takashi; Takei, Masahiro

2013-01-01

Monitoring of thrombogenic process is very important in ventricular assistance devices (VADs) used as temporary or permanent measures in patients with advanced heart failure. Currently, there is a lack of a system which can perform a real-time monitoring of thrombogenic activity. Electrical signals vary according to the change in concentration of coagulation factors as well as the distribution of blood cells, and thus have potential to detect the thrombogenic process in an early stage. In the present work, we have made an assessment of an instrumentation system exploiting the electrical properties of blood. The experiments were conducted using bovine blood. Electrical resistance tomography with eight-electrode sensor was used to monitor the spatio-temporal change in electrical resistivity of blood in thrombogenic and non-thrombogenic condition. Under non-thrombogenic condition, the resistivity was uniform across the cross-section and average resistivity monotonically decreased with time before remaining almost flat. In contrary, under thrombogenic condition, there was non-uniform distribution across the cross-section, and average resistivity fluctuated with time.

Measuring biogeochemical responses to pulses of water

NASA Astrophysics Data System (ADS)

Balcerak, Ernie

2012-05-01

Hydrologic pulses, temporary increases in water inputs such as bouts of precipitation, can affect biogeochemical processes in ecosystems by providing water and nutrient resources. However, ecosystem responses to the water vary. Harms and Grimm conducted experiments to determine how hydrologic pulses and existing moisture conditions interact to affect the biogeochemistry of desert floodplains. During dry and monsoon seasons at their study site in the floodplains of the San Pedro River in Arizona, the researchers experimentally added pulses of water and then measured emissions of several trace gases that are indicators of biological processes. They found that the size of the added hydrologic pulse strongly interacted with existing soil moisture conditions in determining emissions of some trace gases. For instance, following dry conditions, pulses of water stimulated carbon dioxide, methane, and nitric oxide emissions, with larger water pulses stimulating more emissions. However, when soil was already wet, the addition of water pulses had less effect on the emission of these gases. (Journal of Geophysical Research-Biogeosciences, doi:10.1029/2011JG001775, 2012)

Nitrogen processing by grazers in a headwater stream: riparian connections

DOE PAGES

Hill, Walter R.; Griffiths, Natalie A.

2016-10-19

Primary consumers play important roles in the cycling of nutrients in headwater streams, storing assimilated nutrients in growing tissue and recycling them through excretion. Though environmental conditions in most headwater streams and their surrounding terrestrial ecosystems vary considerably over the course of a year, relatively little is known about the effects of seasonality on consumer nutrient recycling these streams. Here, we measured nitrogen accumulated through growth and excreted by the grazing snail Elimia clavaeformis (Pleuroceridae) over the course of 12 months in Walker Branch, identifying close connections between in-stream nitrogen processing and seasonal changes in the surrounding forest.

Facile synthesis of SiO{sub 2} nanoparticles for biomedical applications

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

Scano, A., E-mail: alescano80@tiscali.it; Pilloni, M., E-mail: alescano80@tiscali.it; Cabras, V., E-mail: alescano80@tiscali.it

Silica nanoparticles (SiO{sub 2} NPs) for biomedical applications have been prepared by using a facile modified Stöber-synthesis. Potassium borohydride (KBH{sub 4}) has been introduced in the synthesis procedure in order to control NP size. Several samples have been prepared varying tetraethylorthosilicate (TEOS) concentration, and using different process conditions (temperature, reaction time and atmosphere). In order to study the influence of the process conditions on the NP size, morphology and properties, several characterization techniques were used. Size and morphology of the as-prepared SiO{sub 2} NPs have been studied by using Transmission Electron Microscope (TEM) and Dynamic Light Scattering (DLS) techniques. Structuralmore » characterization was carried out by X-ray powder diffraction. To investigate the SiO{sub 2} NP fluorescence emission properties the fluorescence spectroscopy was also used.« less

77 FR 23813 - Federal Property Suitable as Facilities To Assist the Homeless

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-20

... bldg. 4704 and dispatch--bldg 4707, fair conditions; need repairs Bldg. 8404 Redstone Arsenal Redstone...; current use: varies; fair to poor conditions--bldgs. need repairs; possible asbestos 5 Bldgs. Hunter Army...: 1208, 1209, 1211, 1212, 1221 Comments: Off-site removal only; sq. ft. varies; current use: varies; fair...

Do deglaciated mountainslopes contribute significantly to paraglacial sediment fluxes?

NASA Astrophysics Data System (ADS)

Cossart, Etienne

2013-04-01

Current models of paraglacial sediment generation and transport (Ballantyne, 2002 & 2003) are general in nature; they are probably inaccurate for many specific locations because of the wide range in local or regional geomorphic conditions encountered around the globe. One of the conditions that varies from place to place is the pattern of paraglacial landsliding; it varies in both the magnitude, scale, and timing, and therefore has variable influence on sediment generation. Another condition that varies is the sediment connectivity between slopes and the fluvial system; this can vary due to differences in topography, hydrologic regimes, or transient sediment buffers such as landslide dams. In this paper, we examine the extent to which variability in paraglacial landslide patterns and sediment connectivity may affect the applicability of the general paraglacial model. To achieve this we draw on both existing literature and our field experience from the European Alps and Iceland. Sediment generation and pathways, as influenced by post-glacial collapse of mountain slopes in particular, are studied in three steps. First, the processes involved in rock failure are identified and their possible influence on mass-movement locations at different spatial scales in various places is discussed. This comparison reveals a variable pattern of paraglacial landslide distribution, and allows the local/regional controlling parameters to be identified. Second, the rate of triggering of mass-movement over time is roughly assessed in various settings based on a review of recently published data. This comparison aims to identify typical temporal-models for slope evolution through the time elapsed since deglaciation. Third, an attempt is made to assess the contribution of landsliding to the whole paraglacial cascading system by evaluating the somewhat contradictory findings and assertions from previous authors: Some authors have argued for a high sediment yield at catchment sinks in relation to paraglacial landsliding (Church & Ryder, 1972; Ritter & Ten Brink, 1986), whereas others have identified that some long-lived sediment dams can occur after the deposition of a landslide mass, so that no or little sediment exportation occurs (Korup, 2009; Cossart & Fort, 2008). We add to this debate by developing a typology of geomorphic couples, between paraglacial landslides and other geomorphic processes, and present simulations of sediment yield evolution since glacier disappearance. BALLANTYNE C.K., 2002 - A general model of paraglacial landscape response. The Holocene, 12, 371-376. BALLANTYNE C.K., 2003 - Paraglacial landform succession and sediment storage in deglaciated mountain valleys: theory and approaches to calibration. Zeitschrift für Geomorphologie, 32, 1-18. CHURCH M., & RYDER J.M., 1972 - Paraglacial sedimentation: a consideration of fluvial processes conditioned by glaciation. Geological Society of America Bulletin, 83, 3059-3072. COSSART É., & FORT M., 2008 - Sediment release and storage in early deglaciated areas: Towards an application of the exhaustion model from the case of Massif des Écrins (French Alps) since the Little Ice Age. Norsk Geografisk Tidsskrift - Norwegian Journal of Geography, 62, 115-131. KORUP O., 2009 - Linking landslides, hillslope erosion, and landscape evolution. Earth Surface Processes and Landforms, 34, 1315-1317. RITTER D.F., & TEN BRINK N.W., 1986 - Alluvial fan development and the glacial-glaciofluvial cycle. Nenana Valley, Alaska. Journal of Geology, 94, 613-615.

Zoom-in Simulations of Protoplanetary Disks Starting from GMC Scales

NASA Astrophysics Data System (ADS)

Kuffmeier, Michael; Haugbølle, Troels; Nordlund, Åke

2017-09-01

We investigate the formation of protoplanetary disks around nine solar-mass stars formed in the context of a (40 pc)3 Giant Molecular Cloud model, using ramses adaptive mesh refinement simulations extending over a scale range of about 4 million, from an outer scale of 40 pc down to cell sizes of 2 au. Our most important result is that the accretion process is heterogeneous in multiple ways: in time, in space, and among protostars of otherwise similar mass. Accretion is heterogeneous in time, in the sense that accretion rates vary during the evolution, with generally decreasing profiles, whose slopes vary over a wide range, and where accretion can increase again if a protostar enters a region with increased density and low speed. Accretion is heterogeneous in space, because of the mass distribution, with mass approaching the accreting star-disk system in filaments and sheets. Finally, accretion is heterogeneous among stars, since the detailed conditions and dynamics in the neighborhood of each star can vary widely. We also investigate the sensitivity of disk formation to physical conditions and test their robustness by varying numerical parameters. We find that disk formation is robust even when choosing the least favorable sink particle parameters, and that turbulence cascading from larger scales is a decisive factor in disk formation. We also investigate the transport of angular momentum, finding that the net inward mechanical transport is compensated for mainly by an outward-directed magnetic transport, with a contribution from gravitational torques usually subordinate to the magnetic transport.

Hippocampal Processing of Ambiguity Enhances Fear Memory

PubMed Central

Amadi, Ugwechi; Lim, Seh Hong; Liu, Elizabeth; Baratta, Michael V.; Goosens, Ki Ann

2016-01-01

Despite the ubiquitous use of Pavlovian fear conditioning as a model for fear learning, the highly predictable conditions used in the laboratory do not resemble real-world conditions, where dangerous situations can lead to unpleasant outcomes in unpredictable ways. Here we varied the timing of aversive events following predictive cues in rodents and discovered that temporal ambiguity of aversive events greatly enhances fear. During fear conditioning with unpredictably timed aversive events, pharmacological inactivation of the dorsal hippocampus or optogenetic silencing of CA1 cells during aversive negative prediction errors prevented this enhancement of fear without impacting fear learning for predictable events. Dorsal hippocampal inactivation also prevented ambiguity-related enhancement of fear during auditory fear conditioning under a partial reinforcement schedule. These results reveal that information about the timing and occurrence of aversive events is rapidly acquired and that unexpectedly timed or omitted aversive events generate hippocampal signals to enhance fear learning. PMID:28182526

Hippocampal Processing of Ambiguity Enhances Fear Memory.

PubMed

Amadi, Ugwechi; Lim, Seh Hong; Liu, Elizabeth; Baratta, Michael V; Goosens, Ki A

2017-02-01

Despite the ubiquitous use of Pavlovian fear conditioning as a model for fear learning, the highly predictable conditions used in the laboratory do not resemble real-world conditions, in which dangerous situations can lead to unpleasant outcomes in unpredictable ways. In the current experiments, we varied the timing of aversive events after predictive cues in rodents and discovered that temporal ambiguity of aversive events greatly enhances fear. During fear conditioning with unpredictably timed aversive events, pharmacological inactivation of the dorsal hippocampus or optogenetic silencing of cornu ammonis 1 cells during aversive negative prediction errors prevented this enhancement of fear without affecting fear learning for predictable events. Dorsal hippocampal inactivation also prevented ambiguity-related enhancement of fear during auditory fear conditioning under a partial-reinforcement schedule. These results reveal that information about the timing and occurrence of aversive events is rapidly acquired and that unexpectedly timed or omitted aversive events generate hippocampal signals to enhance fear learning.

Alternative Polyadenylation in Human Diseases

PubMed Central

Chang, Jae-Woong; Yeh, Hsin-Sung

2017-01-01

Varying length of messenger RNA (mRNA) 3′-untranslated region is generated by alternating the usage of polyadenylation sites during pre-mRNA processing. It is prevalent through all eukaryotes and has emerged as a key mechanism for controlling gene expression. Alternative polyadenylation (APA) plays an important role for cell growth, proliferation, and differentiation. In this review, we discuss the functions of APA related with various physiological conditions including cellular metabolism, mRNA processing, and protein diversity in a variety of disease models. We also discuss the molecular mechanisms underlying APA regulation, such as variations in the concentration of mRNA processing factors and RNA-binding proteins, as well as global transcriptome changes under cellular signaling pathway. PMID:29271615

Please Wait, Processing: A Selective Literature Review of the Neurological Understanding of Emotional Processing in ASD and Its Potential Contribution to Neuroeducation

PubMed Central

Shyman, Eric

2017-01-01

Autism spectrum disorder (ASD) and its corresponding conditions have been investigated from a multitude of perspectives resulting in varying understandings of its origin, its outplay, its prognosis, and potential methods of intervention and education for individuals with the disorder. One area that has contributed significantly to providing a different type of understanding is that of neuroscience, and specifically neuroimaging. This paper will offer a selective literature review of research that investigates the role of emotional processing in ASD, and how a deepening of this line of understanding can be used to inform more comprehensive educational practices. PMID:29149018

An exemplar-familiarity model predicts short-term and long-term probe recognition across diverse forms of memory search.

PubMed

Nosofsky, Robert M; Cox, Gregory E; Cao, Rui; Shiffrin, Richard M

2014-11-01

Experiments were conducted to test a modern exemplar-familiarity model on its ability to account for both short-term and long-term probe recognition within the same memory-search paradigm. Also, making connections to the literature on attention and visual search, the model was used to interpret differences in probe-recognition performance across diverse conditions that manipulated relations between targets and foils across trials. Subjects saw lists of from 1 to 16 items followed by a single item recognition probe. In a varied-mapping condition, targets and foils could switch roles across trials; in a consistent-mapping condition, targets and foils never switched roles; and in an all-new condition, on each trial a completely new set of items formed the memory set. In the varied-mapping and all-new conditions, mean correct response times (RTs) and error proportions were curvilinear increasing functions of memory set size, with the RT results closely resembling ones from hybrid visual-memory search experiments reported by Wolfe (2012). In the consistent-mapping condition, new-probe RTs were invariant with set size, whereas old-probe RTs increased slightly with increasing study-test lag. With appropriate choice of psychologically interpretable free parameters, the model accounted well for the complete set of results. The work provides support for the hypothesis that a common set of processes involving exemplar-based familiarity may govern long-term and short-term probe recognition across wide varieties of memory- search conditions. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Parallel steady state studies on a milliliter scale accelerate fed-batch bioprocess design for recombinant protein production with Escherichia coli.

PubMed

Schmideder, Andreas; Cremer, Johannes H; Weuster-Botz, Dirk

2016-11-01

In general, fed-batch processes are applied for recombinant protein production with Escherichia coli (E. coli). However, state of the art methods for identifying suitable reaction conditions suffer from severe drawbacks, i.e. direct transfer of process information from parallel batch studies is often defective and sequential fed-batch studies are time-consuming and cost-intensive. In this study, continuously operated stirred-tank reactors on a milliliter scale were applied to identify suitable reaction conditions for fed-batch processes. Isopropyl β-d-1-thiogalactopyranoside (IPTG) induction strategies were varied in parallel-operated stirred-tank bioreactors to study the effects on the continuous production of the recombinant protein photoactivatable mCherry (PAmCherry) with E. coli. Best-performing induction strategies were transferred from the continuous processes on a milliliter scale to liter scale fed-batch processes. Inducing recombinant protein expression by dynamically increasing the IPTG concentration to 100 µM led to an increase in the product concentration of 21% (8.4 g L -1 ) compared to an implemented high-performance production process with the most frequently applied induction strategy by a single addition of 1000 µM IPGT. Thus, identifying feasible reaction conditions for fed-batch processes in parallel continuous studies on a milliliter scale was shown to be a powerful, novel method to accelerate bioprocess design in a cost-reducing manner. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1426-1435, 2016. © 2016 American Institute of Chemical Engineers.

Analysis of unsteady wave processes in a rotating channel

NASA Technical Reports Server (NTRS)

Larosiliere, L. M.; Mawid, M.

1993-01-01

The impact of passage rotation on the gas dynamic wave processes is analyzed through a numerical simulation of ideal shock-tube flow in a closed rotating-channel. Initial conditions are prescribed by assuming homentropic solid-body rotation. Relevant parameters of the problem such as wheel Mach number, hub-to-tip radius ratio, length-to-tip radius ratio, diaphragm temperature ratio, and diaphragm pressure ratio are varied. The results suggest possible criteria for assessing the consequences of passage rotation on the wave processes, and they may therefore be applicable to pressure-exchange wave rotors. It is shown that for a fixed geometry and initial conditions, the contact interface acquires a distorted three-dimensional time-dependent orientation at non-zero wheel Mach numbers. At a fixed wheel Mach number, the level of distortion depends primarily on the density ratio across the interface as well as the hub-to-tip radius ratio. Rarefaction fronts, shocks, and contact interfaces are observed to propagate faster with increasing wheel Mach number.

NEET-AMM Final Technical Report on Laser Direct Manufacturing (LDM) for Nuclear Power Components

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

Anderson, Scott; Baca, Georgina; O'Connor, Michael

2015-12-31

Final technical report summarizes the program progress and technical accomplishments of the Laser Direct Manufacturing (LDM) for Nuclear Power Components project. A series of experiments varying build process parameters (scan speed and laser power) were conducted at the outset to establish the optimal build conditions for each of the alloys. Fabrication was completed in collaboration with Quad City Manufacturing Laboratory (QCML). The density of all sample specimens was measured and compared to literature values. Optimal build process conditions giving fabricated part densities close to literature values were chosen for making mechanical test coupons. Test coupons whose principal axis is onmore » the x-y plane (perpendicular to build direction) and on the z plane (parallel to build direction) were built and tested as part of the experimental build matrix to understand the impact of the anisotropic nature of the process.. Investigations are described 316L SS, Inconel 600, 718 and 800 and oxide dispersion strengthed 316L SS (Yttria) alloys.« less

Analysis of unsteady wave processes in a rotating channel

NASA Astrophysics Data System (ADS)

Larosiliere, Louis M.; Mawid, M.

1993-06-01

The impact of passage rotation on the gas dynamic wave processes is analyzed through a numerical simulation of ideal shock-tube flow in a closed rotating-channel. Initial conditions are prescribed by assuming homentropic solid-body rotation. Relevant parameters of the problem such as wheel Mach number, hub-to-tip radius ratio, length-to-tip radius ratio, diaphragm temperature ratio, and diaphragm pressure ratio are varied. The results suggest possible criteria for assessing the consequences of passage rotation on the wave processes, and they may therefore be applicable to pressure-exchange wave rotors. It is shown that for a fixed geometry and initial conditions, the contact interface acquires a distorted three-dimensional time-dependent orientation at non-zero wheel Mach numbers. At a fixed wheel Mach number, the level of distortion depends primarily on the density ratio across the interface as well as the hub-to-tip radius ratio. Rarefaction fronts, shocks, and contact interfaces are observed to propagate faster with increasing wheel Mach number.

Current Use of Evidence-Based Medicine in Pediatric Spine Surgery.

PubMed

Oetgen, Matthew E

2018-04-01

Evidence-based medicine (EBM) is a process of decision-making aimed at making the best clinical decisions as they relate to patients' health. The current use of EBM in pediatric spine surgery is varied, based mainly on the availability of high-quality data. The use of EBM is limited in idiopathic scoliosis, whereas EBM has been used to investigate the treatment of pediatric spondylolysis. Studies on early onset scoliosis are of low quality, making EBM difficult in this condition. Future focus and commitment to study quality in pediatric spinal surgery will likely increase the role of EBM in these conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

The effect of preparation conditions on the structure and mechanical properties of reaction-sintered silicon nitride

NASA Technical Reports Server (NTRS)

Heinrich, J.

1980-01-01

The microstructure of reaction sintered silicon nitride (RSSN) was changed over a wide range by varying the grain density, grain size of the silicon starting powder, nitriding conditions, and by introducing artificial pores. The influence of single microstructural parameters on mechanical properties like room temperature strength, creep behavior, and resistance to thermal shock was investigated. The essential factors influencing these properties were found to be total porosity, pore size distribution, and the fractions of alpha and beta Si3N4. In view of high temperature engineering applications of RSSN, potentials for optimizing the material's properties by controlled processing are discussed.

SENSITIVITY OF CONDITIONAL-DISCRIMINATION PERFORMANCE TO WITHIN-SESSION VARIATION OF REINFORCER FREQUENCY

PubMed Central

Ward, Ryan D; Odum, Amy L

2008-01-01

The present experiment developed a methodology for assessing sensitivity of conditional-discrimination performance to within-session variation of reinforcer frequency. Four pigeons responded under a multiple schedule of matching-to-sample components in which the ratio of reinforcers for correct S1 and S2 responses was varied across components within session. Initially, five components, each arranging a different reinforcer-frequency ratio (from 1∶9 to 9∶1), were presented randomly within a session. Under this condition, sensitivity to reinforcer frequency was low. Sensitivity failed to improve after extended exposure to this condition, and under a condition in which only three reinforcer-frequency ratios were varied within session. In a later condition, three reinforcer-frequency ratios were varied within session, but the reinforcer-frequency ratio in effect was differentially signaled within each component. Under this condition, values of sensitivity were similar to those traditionally obtained when reinforcer-frequency ratios for correct responses are varied across conditions. The effects of signaled vs. unsignaled reinforcer-frequency ratios were replicated in two subsequent conditions. The present procedure could provide a practical alternative to parametric variation of reinforcer frequency across conditions and may be useful in characterizing the effects of a variety of manipulations on steady-state sensitivity to reinforcer frequency. PMID:19070338

On creativity of slime mould

NASA Astrophysics Data System (ADS)

Adamatzky, Andrew; Armstrong, Rachel; Jones, Jeff; Gunji, Yukio-Pegio

2013-07-01

Slime mould Physarum polycephalum is large single cell with intriguingly smart behaviour. The slime mould shows outstanding abilities to adapt its protoplasmic network to varying environmental conditions. The slime mould can solve tasks of computational geometry, image processing, logics and arithmetics when data are represented by configurations of attractants and repellents. We attempt to map behavioural patterns of slime onto the cognitive control vs. schizotypy spectrum phase space and thus interpret slime mould's activity in terms of creativity.

Wastewater Management Alternatives for the Cleveland - Akron, Three Rivers Watershed Area. Technical Appendix - Phase II. System Design and Estimate of Cost.

DTIC Science & Technology

1973-02-01

established. Secondly, the applicable process sequence to most economically meet these requirements under local enviromental constraints must be...concentrations are highest for receiving waters containing cold water fisheries. Allowable fecal coliform bacteria counts vary seasonally and dictate...handling system has also been modified to include gravity waste activated sludge thickening and heat conditioning of the combined raw sludge after

Musical Experience Influences Statistical Learning of a Novel Language

PubMed Central

Shook, Anthony; Marian, Viorica; Bartolotti, James; Schroeder, Scott R.

2014-01-01

Musical experience may benefit learning a new language by enhancing the fidelity with which the auditory system encodes sound. In the current study, participants with varying degrees of musical experience were exposed to two statistically-defined languages consisting of auditory Morse-code sequences which varied in difficulty. We found an advantage for highly-skilled musicians, relative to less-skilled musicians, in learning novel Morse-code based words. Furthermore, in the more difficult learning condition, performance of lower-skilled musicians was mediated by their general cognitive abilities. We suggest that musical experience may lead to enhanced processing of statistical information and that musicians’ enhanced ability to learn statistical probabilities in a novel Morse-code language may extend to natural language learning. PMID:23505962

Linking Local Scale Ecosystem Science to Regional Scale Management

NASA Astrophysics Data System (ADS)

Shope, C. L.; Tenhunen, J.; Peiffer, S.

2012-04-01

Ecosystem management with respect to sufficient water yield, a quality water supply, habitat and biodiversity conservation, and climate change effects requires substantial observational data at a range of scales. Complex interactions of local physical processes oftentimes vary over space and time, particularly in locations with extreme meteorological conditions. Modifications to local conditions (ie: agricultural land use changes, nutrient additions, landscape management, water usage) can further affect regional ecosystem services. The international, inter-disciplinary TERRECO research group is intensively investigating a variety of local processes, parameters, and conditions to link complex physical, economic, and social interactions at the regional scale. Field-based meteorology, hydrology, soil physics, plant production, solute and sediment transport, economic, and social behavior data were measured in a South Korean catchment. The data are used to parameterize suite of models describing local to landscape level water, sediment, nutrient, and monetary relationships. We focus on using the agricultural and hydrological SWAT model to synthesize the experimental field data and local-scale models throughout the catchment. The approach of our study was to describe local scientific processes, link potential interrelationships between different processes, and predict environmentally efficient management efforts. The Haean catchment case study shows how research can be structured to provide cross-disciplinary scientific linkages describing complex ecosystems and landscapes that can be used for regional management evaluations and predictions.

Evaluating the impact of ammonia fiber expansion (AFEX) pretreatment conditions on the cost of ethanol production.

PubMed

Bals, Bryan; Wedding, Chris; Balan, Venkatesh; Sendich, Elizabeth; Dale, Bruce

2011-01-01

Ammonia fiber expansion (AFEX) pretreatment is an ammonia-based process for improving the susceptibility of lignocellulosic biomass to enzymatic attack. Four parameters--ammonia loading, water loading, reaction temperature, and residence time--can be varied in order to optimize AFEX pretreatment. The effect of these parameters on process economics of ethanol production was studied using a leading biorefinery model. Ammonia loading and residence time had the greatest impact on the economics of ethanol production, primarily due to processing costs for the chilled water condenser and the capital cost of the AFEX reactor. Water loading and reaction temperature had only modest impact on process economics. In addition, the impact of pretreatment conditions on makeup ammonia requirements was explored experimentally, which ranged from 15 to 25 g ammonia/kg biomass. Overall, pretreatment conditions can change the costs of ethanol production by up to 35 cents per gallon ethanol in an 850 ton/day refinery. By linking the results obtained from this Aspen model to experimental results for ethanol production and makeup ammonia recovery, this study can be used to create an economic optimum for AFEX pretreatment in contrast with simply maximizing fermentable sugar production. Copyright © 2010 Elsevier Ltd. All rights reserved.

Preparation and recrystallization behavior of spray-dried co-amorphous naproxen-indomethacin.

PubMed

Beyer, Andreas; Radi, Lydia; Grohganz, Holger; Löbmann, Korbinian; Rades, Thomas; Leopold, Claudia S

2016-07-01

To improve the dissolution properties and the physical stability of amorphous active pharmaceutical ingredients, small molecule stabilizing agents may be added to prepare co-amorphous systems. The objective of the study was to investigate if spray-drying allows the preparation of co-amorphous drug-drug systems such as naproxen-indomethacin and to examine the influence of the process conditions on the resulting initial sample crystallinity and the recrystallization behavior of the drug(s). For this purpose, the process parameters inlet temperature and pump feed rate were varied according to a 2(2) factorial design and the obtained samples were analyzed with X-ray powder diffractometry and Fourier-transformed infrared spectroscopy. Evaluation of the data revealed that the preparation of fully amorphous samples could be achieved depending on the process conditions. The resulting recrystallization behavior of the samples, such as the total recrystallization rate, the individual recrystallization rates of naproxen and indomethacin as well as the polymorphic form of indomethacin that was formed were influenced by these process conditions. For initially amorphous samples, it was found that naproxen and indomethacin recrystallized almost simultaneously, which supports the theory of formation of drug-drug heterodimers in the co-amorphous phase. Copyright © 2016 Elsevier B.V. All rights reserved.

Hybrid modeling as a QbD/PAT tool in process development: an industrial E. coli case study.

PubMed

von Stosch, Moritz; Hamelink, Jan-Martijn; Oliveira, Rui

2016-05-01

Process understanding is emphasized in the process analytical technology initiative and the quality by design paradigm to be essential for manufacturing of biopharmaceutical products with consistent high quality. A typical approach to developing a process understanding is applying a combination of design of experiments with statistical data analysis. Hybrid semi-parametric modeling is investigated as an alternative method to pure statistical data analysis. The hybrid model framework provides flexibility to select model complexity based on available data and knowledge. Here, a parametric dynamic bioreactor model is integrated with a nonparametric artificial neural network that describes biomass and product formation rates as function of varied fed-batch fermentation conditions for high cell density heterologous protein production with E. coli. Our model can accurately describe biomass growth and product formation across variations in induction temperature, pH and feed rates. The model indicates that while product expression rate is a function of early induction phase conditions, it is negatively impacted as productivity increases. This could correspond with physiological changes due to cytoplasmic product accumulation. Due to the dynamic nature of the model, rational process timing decisions can be made and the impact of temporal variations in process parameters on product formation and process performance can be assessed, which is central for process understanding.

Changes in Soil Minerology Reduce Phosphorus Mobility During Anoxic Soil Conditions

NASA Astrophysics Data System (ADS)

Giri, S. K.; Geohring, L. D.; Richards, B. K.; Walter, M.; Steenhuis, T. S.

2008-05-01

Phosphorus (P) transfer from the landscape to receiving waters is an important environmental concern because these diffuse losses may cause widespread water quality impairments which can accelerate freshwater eutrophication. Phosphorus (P) mobilization from soil to surface and subsurface flow paths is controlled by numerous factors, and thus it can vary greatly with time and landscape scale. To determine whether P mobilization during soil saturation in the landscape was caused or controlled by complexation, iron reduction or ligand exchange, experiments were carried out to better characterize the interrelationships of varying P sources with dissolved organic carbon (DOC) and soil anoxic conditions. The soil incubation experiments consisted of treatments with distilled water, 5 mM acetic acid (HAc), 0.05% humic acid (HA) and glucose (40 mM) at 26 o C under anaerobic conditions to isolate effects of the various P exchange processes. The experimental results suggest that during soil saturation, the loosely bound P, which is primarily associated with iron oxyhydroxides, was mobilized by both reduction and complexation processes. Good correlations were observed between ferrous iron (Fe+2) and DOC, and between total dissolved phosphorus (TDP) and DOC, facilitating P desorption to the soil water. The anaerobic soil conditions with different P sources also indicated that mineralization facilitated P mobility, mainly due to chelation (humics and metabolites) and as a result of the bio-reduction of iron when fresh litter and grass were present. The organic P sources which are rich in carbohydrate and cellulose and that undergo fermentation due to the action of lactate forming organisms also caused a release of P. The easily metabolizable DOC sources lead to intensive bio-reduction of soil with the release of Fe, however this did not necessarily appear to cause more TDP in the soil solution. The varying P additions in soils with water, HAc and glucose (40mm) before and after soil incubation showed higher P sorption than aerobic soil due to reduced iron (Fe+2) - P mineral formation. Some of the readily available P in the soil solution tended to co-precipitate quickly with Fe, Al, Ca, and Mn, but it also resulted in the formation of earthy masses of vivianite [Fe2+3(PO4)2 . 8 H20], thus almost completely immobilizing P. These findings suggest that where conditions in the landscape are saturated, but remain stagnant for extended time periods, P additions may not necessarily enhance leaching once hydrological transport resumes. The temporal nature of P mobilization processes combined with rapid (i.e., preferential flow) hydrological transport appears to have a more important role in controlling P transport through the landscape.

Via fill properties of organic BARCs in dual-damascene application

NASA Astrophysics Data System (ADS)

Huang, Runhui

2004-05-01

With the introduction of copper as the interconnect metal, the Dual Damascene (DD) process has been integrated into integrated circuit (IC) device fabrication. The DD process utilizes organic bottom anti-reflective coatings (BARCs) not only to eliminate the thin film interference effects but also to act as via fill materials. However, three serious processing problems are encountered with organic BARCs. One is the formation of voids, which are trapped gas bubbles (evaporating solvent, byproduct of the curing reaction and air) inside the vias. Another problem is non-uniform BARC layer thickness in different via pitch areas. The third problem is the formation of fences during plasma etch. Fences are formed from materials that are removed by plasma and subsequently deposited on the sidewall surrounding the via openings during the etching process. Voids can cause variations in BARC top thickness, optical properties, via fill percentage, and plasma etch rate. This study focuses on the factors that influence the formation of voids and addresses the ways to eliminate them by optimizing the compositions of formulations and the processing conditions. Effects of molecular weight of the polymer, nature of the crosslinker, additives, and bake temperature were examined. The molecular weight of the polymer is one of the important factors that needs to be controlled carefully. Polymers with high molecular weights tend to trap voids inside the vias. Low molecular weight polymers have low Tg and low viscosity, which enables good thermal flow so that the BARC can fill vias easily without voids. Several kinds of crosslinkers were investigated in this study. When used with the same polymer system, formulations with different crosslinkers show varying results that affect planar fill, sidewall coverage, and, in some cases, voids. Additives also can change via fill behavior dramatically, and choosing the right additive will improve the via fill property. Processing conditions such as bake temperature also greatly affect via fill. Depending on the polymer thermal property and crosslinking reaction, varying the bake temperature can change the via fill behavior of the BARC. By understanding the nature of the polymer, the crosslinking reaction, and the processing conditions, we are able to design BARCs with better flow property to provide planar topography without voids inside the vias.

Influence of thermomechanical processing on biomechanical compatibility and electrochemical behavior of new near beta alloy, Ti-20.6Nb-13.6Zr-0.5V

PubMed Central

Mohammed, Mohsin Talib; Khan, Zahid A; Manivasagam, Geetha; Siddiquee, Arshad N

2015-01-01

This paper presents the results for the effect of different methods of thermomechanical processing on the mechanical properties and electrochemical behavior of metastable β alloy Ti-20.6Nb-13.6Zr-0.5V (TNZV). The thermomechanical processing included hot working, solution heat treatments at different temperatures, and cooling rates in addition to aging. The thermomechanical processing conditions used in the study resulted in attainment of a wide range of microstructures with varying spatial distributions and morphologies of elongated/equiaxed α, β phases, or martensite, as a result of which several tensile properties were achieved. Aging treatment led to an increase in hardness, elastic modulus, and tensile strength and a decrease in ductility (elongation). Electrochemical tests indicated that the TNZV alloy undergoes spontaneous passivation due to spontaneous formation of an oxide film in the environment of the human body. Because the air-cooled samples possessed high hardness and also a fine grain size, they showed a lower corrosion rate than the samples treated under other conditions. PMID:26491324

Regulation of the forming process and the set voltage distribution of unipolar resistance switching in spin-coated CoFe2O4 thin films.

PubMed

Mustaqima, Millaty; Yoo, Pilsun; Huang, Wei; Lee, Bo Wha; Liu, Chunli

2015-01-01

We report the preparation of (111) preferentially oriented CoFe2O4 thin films on Pt(111)/TiO2/SiO2/Si substrates using a spin-coating process. The post-annealing conditions and film thickness were varied for cobalt ferrite (CFO) thin films, and Pt/CFO/Pt structures were prepared to investigate the resistance switching behaviors. Our results showed that resistance switching without a forming process is preferred to obtain less fluctuation in the set voltage, which can be regulated directly from the preparation conditions of the CFO thin films. Therefore, instead of thicker film, CFO thin films deposited by two times spin-coating with a thickness about 100 nm gave stable resistance switching with the most stable set voltage. Since the forming process and the large variation in set voltage have been considered as serious obstacles for the practical application of resistance switching for non-volatile memory devices, our results could provide meaningful insights in improving the performance of ferrite material-based resistance switching memory devices.

A game theoretic approach to a finite-time disturbance attenuation problem

NASA Technical Reports Server (NTRS)

Rhee, Ihnseok; Speyer, Jason L.

1991-01-01

A disturbance attenuation problem over a finite-time interval is considered by a game theoretic approach where the control, restricted to a function of the measurement history, plays against adversaries composed of the process and measurement disturbances, and the initial state. A zero-sum game, formulated as a quadratic cost criterion subject to linear time-varying dynamics and measurements, is solved by a calculus of variation technique. By first maximizing the quadratic cost criterion with respect to the process disturbance and initial state, a full information game between the control and the measurement residual subject to the estimator dynamics results. The resulting solution produces an n-dimensional compensator which expresses the controller as a linear combination of the measurement history. A disturbance attenuation problem is solved based on the results of the game problem. For time-invariant systems it is shown that under certain conditions the time-varying controller becomes time-invariant on the infinite-time interval. The resulting controller satisfies an H(infinity) norm bound.

Preliminary analysis of species partitioning in the DWPF melter. Sludge batch 7A

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

Choi, A. S.; Smith III, F. G.; McCabe, D. J.

2017-01-01

The work described in this report is preliminary in nature since its goal was to demonstrate the feasibility of estimating the off-gas carryover from the Defense Waste Processing Facility (DWPF) melter based on a simple mass balance using measured feed and glass pour stream (PS) compositions and time-averaged melter operating data over the duration of one canister-filling cycle. The DWPF has been in radioactive operation for over 20 years processing a wide range of high-level waste (HLW) feed compositions under varying conditions such as bubbled vs. non-bubbled and feeding vs. idling. So it is desirable to find out how themore » varying feed compositions and operating parameters would have impacted the off-gas entrainment. However, the DWPF melter is not equipped with off-gas sampling or monitoring capabilities, so it is not feasible to measure off-gas entrainment rates directly. The proposed method provides an indirect way of doing so.« less

Estimating and mapping ecological processes influencing microbial community assembly

PubMed Central

Stegen, James C.; Lin, Xueju; Fredrickson, Jim K.; Konopka, Allan E.

2015-01-01

Ecological community assembly is governed by a combination of (i) selection resulting from among-taxa differences in performance; (ii) dispersal resulting from organismal movement; and (iii) ecological drift resulting from stochastic changes in population sizes. The relative importance and nature of these processes can vary across environments. Selection can be homogeneous or variable, and while dispersal is a rate, we conceptualize extreme dispersal rates as two categories; dispersal limitation results from limited exchange of organisms among communities, and homogenizing dispersal results from high levels of organism exchange. To estimate the influence and spatial variation of each process we extend a recently developed statistical framework, use a simulation model to evaluate the accuracy of the extended framework, and use the framework to examine subsurface microbial communities over two geologic formations. For each subsurface community we estimate the degree to which it is influenced by homogeneous selection, variable selection, dispersal limitation, and homogenizing dispersal. Our analyses revealed that the relative influences of these ecological processes vary substantially across communities even within a geologic formation. We further identify environmental and spatial features associated with each ecological process, which allowed mapping of spatial variation in ecological-process-influences. The resulting maps provide a new lens through which ecological systems can be understood; in the subsurface system investigated here they revealed that the influence of variable selection was associated with the rate at which redox conditions change with subsurface depth. PMID:25983725

[Morphological characteristics of kidneys connective tissue of mature fetuses and newborns from mothers, whose pregnancy was complicated by preeclampsia of varying degrees of severity].

PubMed

Sorokina, Iryna V; Myroshnychenko, Mykhailo S; Kapustnyk, Nataliia V; Khramova, Tetyana O; Dehtiarova, Oksana V; Danylchenko, Svitlana I

2018-01-01

Introduction: The kidneys connective tissue condition in the antenatal period affects the formation of tissues and it changes with the development of various general pathological processes in this organ. The aim of the study was to identify the morphological features of kidneys connective tissue of fetuses and newborns from mothers whose pregnancy was complicated by preeclampsia of varying degrees of severity. Materials and methods: The material of the study was the tissue of kidneys of mature fetuses and newborns from mothers with physiological pregnancy (28 cases), as well as from mothers whose pregnancy was complicated by preeclampsia of varying degrees of severity (78 cases). Immunohistochemical study was performed by an indirect Coons method according to M. Brosman's technique using monoclonal antibodies to collagen type I, III and IV. Results: The kidneys connective tissue of fetuses and newborns developing under the maternal preeclampsia conditions is characterized by the qualitative and quantitative changes that indicate the development of sclerotic processes in this organ, the severity of which increase with the age and with the increase of the maternal preeclampsia severity. Qualitative changes are characterized by an increase of the fibrous component, thickening of the bundles of connective tissue fibers, and a decrease in the distance between them. Quantitative changes are characterized by a pronounced predominance of collagen fibers over elastic fibers, almost total absence in some field of view elastic fibers and the violation of the content of collagen type I, III and IV. Conclusion: Maternal preeclampsia underlies the development of qualitative and quantitative changes in kidneys connective tissue of fetuses and newborns, which as a result will lead to disruption of the functions of these organs in such children.

How chemical information processing interferes with face processing: a magnetoencephalographic study.

PubMed

Walla, Peter; Mayer, Dagmar; Deecke, Lüder; Lang, Wilfried

2005-01-01

Magnetic field changes related to face encoding were recorded in 20 healthy young participants. Faces had to be deeply encoded under four kinds of simultaneous nasal chemical stimulation. Neutral room air, phenyl ethyl alcohol (PEA, rose flavor), carbon dioxide (CO2, pain), and hydrogen sulfide (H2S, rotten eggs flavor) were used as chemical stimuli. PEA and H2S represented odor stimuli, whereas CO2 was used for trigeminal stimulation (pain sensation). After the encoding of faces, the respective recognition performances were tested focusing on recognition effects related to specific chemical stimulation during encoding. The number of correctly recognized faces (hits) varied between chemical conditions. PEA stimulation during face encoding significantly increased the number of hits compared to the control condition. H2S also led to an increased mean number of hits, whereas simultaneous CO2 administration during face encoding resulted in a reduction. Analysis of the physiological data revealed two latency regions of interest. Compared to the control condition, both olfactory stimulus conditions resulted in reduced activity components peaking at about 260 ms after stimulus onset, whereas CO2 produced a strongly pronounced enhanced activity component peaking at about 700 ms after stimulus onset. Both olfactory conditions elicited only weak enhanced activities at about 700 ms, and CO2 did not show any difference activity at 260 ms after stimulus onset compared to the control condition. It is concluded that the early activity differences represent subconscious olfactory information processing leading to enhanced memory performances irrespective of the hedonic value, at least if they are only subconsciously processed. The later activity is suggested to reflect conscious CO2 perception negatively affecting face encoding and therefore leading to reduced subsequent face recognition. We interpret that conscious processing of nasal chemical stimulation competes with deep face encoding with respect to cortical resources, whereas subconscious processing of nasal chemical stimulation does not.

The effects of interstimulus interval on event-related indices of attention: an auditory selective attention test of perceptual load theory.

PubMed

Gomes, Hilary; Barrett, Sophia; Duff, Martin; Barnhardt, Jack; Ritter, Walter

2008-03-01

We examined the impact of perceptual load by manipulating interstimulus interval (ISI) in two auditory selective attention studies that varied in the difficulty of the target discrimination. In the paradigm, channels were separated by frequency and target/deviant tones were softer in intensity. Three ISI conditions were presented: fast (300ms), medium (600ms) and slow (900ms). Behavioral (accuracy and RT) and electrophysiological measures (Nd, P3b) were observed. In both studies, participants evidenced poorer accuracy during the fast ISI condition than the slow suggesting that ISI impacted task difficulty. However, none of the three measures of processing examined, Nd amplitude, P3b amplitude elicited by unattended deviant stimuli, or false alarms to unattended deviants, were impacted by ISI in the manner predicted by perceptual load theory. The prediction based on perceptual load theory, that there would be more processing of irrelevant stimuli under conditions of low as compared to high perceptual load, was not supported in these auditory studies. Task difficulty/perceptual load impacts the processing of irrelevant stimuli in the auditory modality differently than predicted by perceptual load theory, and perhaps differently than in the visual modality.

Process feasibility study in support of silicon material task 1

NASA Technical Reports Server (NTRS)

Fang, C. S.; Hansen, K. C.; Miller, J. W., Jr.; Yaws, C. L.

1978-01-01

Initial results for gas thermal conductivity of silicon tetrafluoride and trichlorosilane are reported in respective temperature ranges of 25 to 400 C and 50 to 400 C. For chemical engineering analyses, the preliminary process design for the original silane process of Union Carbide was completed for Cases A and B, Regular and Minimum Process Storage. Included are raw material usage, utility requirements, major process equipment lists, and production labor requirements. Because of the large differences in surge tankage between major unit operations the fixed capital investment varied from $19,094,000 to $11,138,000 for Cases A and B, respectively. For the silane process the original flowsheet was revised for a more optimum arrangement of major equipment, raw materials and operating conditions. The initial issue of the revised flowsheet (Case C) for the silane process indicated favorable cost benefits over the original scheme.

Characteristic time scales for diffusion processes through layers and across interfaces

NASA Astrophysics Data System (ADS)

Carr, Elliot J.

2018-04-01

This paper presents a simple tool for characterizing the time scale for continuum diffusion processes through layered heterogeneous media. This mathematical problem is motivated by several practical applications such as heat transport in composite materials, flow in layered aquifers, and drug diffusion through the layers of the skin. In such processes, the physical properties of the medium vary across layers and internal boundary conditions apply at the interfaces between adjacent layers. To characterize the time scale, we use the concept of mean action time, which provides the mean time scale at each position in the medium by utilizing the fact that the transition of the transient solution of the underlying partial differential equation model, from initial state to steady state, can be represented as a cumulative distribution function of time. Using this concept, we define the characteristic time scale for a multilayer diffusion process as the maximum value of the mean action time across the layered medium. For given initial conditions and internal and external boundary conditions, this approach leads to simple algebraic expressions for characterizing the time scale that depend on the physical and geometrical properties of the medium, such as the diffusivities and lengths of the layers. Numerical examples demonstrate that these expressions provide useful insight into explaining how the parameters in the model affect the time it takes for a multilayer diffusion process to reach steady state.

Characteristic time scales for diffusion processes through layers and across interfaces.

PubMed

Carr, Elliot J

2018-04-01

This paper presents a simple tool for characterizing the time scale for continuum diffusion processes through layered heterogeneous media. This mathematical problem is motivated by several practical applications such as heat transport in composite materials, flow in layered aquifers, and drug diffusion through the layers of the skin. In such processes, the physical properties of the medium vary across layers and internal boundary conditions apply at the interfaces between adjacent layers. To characterize the time scale, we use the concept of mean action time, which provides the mean time scale at each position in the medium by utilizing the fact that the transition of the transient solution of the underlying partial differential equation model, from initial state to steady state, can be represented as a cumulative distribution function of time. Using this concept, we define the characteristic time scale for a multilayer diffusion process as the maximum value of the mean action time across the layered medium. For given initial conditions and internal and external boundary conditions, this approach leads to simple algebraic expressions for characterizing the time scale that depend on the physical and geometrical properties of the medium, such as the diffusivities and lengths of the layers. Numerical examples demonstrate that these expressions provide useful insight into explaining how the parameters in the model affect the time it takes for a multilayer diffusion process to reach steady state.

Cryophenomena in the Cold Desert of Atacama

NASA Astrophysics Data System (ADS)

Buchroithner, Dr.; Trombotto, Dr.

2012-04-01

The study area of the Valle de Barrancas Blancas in the High Atacama Andes of Chile (68°39' W, 27°02' S), a kind of Patagonian "bajo sin salida", shows well preserved landforms resulting from a combination of slope, eolian, lacustrine/litoral, fluvial, glacial and periglacial regimes. They permit the reconstruction of geomorphological processes within this isolated catchment of approximately 160 km2. The mean annual air temperature varies between -2 and -4 °C and the precipitation is approximately 150 mm/a. Snowfall is frequent but the snow is quickly sublimated, redeposited and/or covered by cryosediments, i.e. mainly pumice pebbles. Water bodies present icings, even in summer. Regarding its climatic conditions the study area represents an extremely cold desertic region. Extremophile microfauna was also found. The area displays both in situ mountain permafrost and creeping permafrost. The active layer is 30 to 45 cm thick. It is a periglacial macro-environment where interdependent processes, and not only cryogenic processes but also erosion and eolian deposition and the action of fluvial washout mainly caused by precipitation, accumulation, retransportation/redeposition and melting of snow, play an important role. The cryogenic geomorphology of the Valle de Barrancas Blancas is varied and contains microforms such as patterned ground and microforms caused by cryoturbation, as well as mesoforms like rockglaciers and cryoplanation surfaces. Slopes are strongly affected by gelifluction. New cryoforms in South America and in the Southern Hemisphere like the Atacama Pingo (Pingo atacamensis) and Permafrosted Dunes ("Dunas heladas") were found. Intense niveo-eolian processes participate in the erosion of preexisting landforms, in the formation of subterraneous ice layers, and the retransportation/redeposition of snow and sediments. Studies of this periglacial environment are crucial for the understanding of Tundrean paleoenvironments and Martian conditions.

Influence of environmental conditions on the toxicokinetics of cadmium in the marine copepod Acartia tonsa.

PubMed

Pavlaki, Maria D; Morgado, Rui G; van Gestel, Cornelis A M; Calado, Ricardo; Soares, Amadeu M V M; Loureiro, Susana

2017-11-01

mMarine and estuarine ecosystems are highly productive areas that often act as a final sink for several pollutants, such as cadmium. Environmental conditions in these habitats can affect metal speciation, as well as its uptake and depuration by living organisms. The aim of this study was to assess cadmium uptake and depuration rates in the euryhaline calanoid copepod Acartia tonsa under different pH, salinity and temperature conditions. Cadmium speciation did not vary with changing pH or temperature, but varied with salinity. Free Cd 2+ ion activity increased with decreasing salinities resulting in increased cadmium concentrations in A. tonsa. However, uptake rate, derived using free Cd 2+ ion activity, showed no significant differences at different salinities indicating a simultaneous combined effect of Cd 2+ speciation and metabolic rates for osmoregulation. Cadmium concentration in A. tonsa and uptake rate increased with increasing pH, showing a peak at the intermediate pH of 7.5, while depuration rate fluctuated, thus suggesting that both parameters are mediated by metabolic processes (to maintain homeostasis at pH levels lower than normal) and ion competition at membrane binding sites. Cadmium concentration in A. tonsa, uptake and depuration rates increased with increasing temperature, a trend that can be attributed to an increase in metabolic energy demand at higher temperatures. The present study shows that cadmium uptake and depuration rates in the marine copepod A. tonsa is mostly affected by biological processes, mainly driven by metabolic mechanisms, and to a lesser extent by metal speciation in the exposure medium. Copyright © 2017 Elsevier Inc. All rights reserved.

Separating monocular and binocular neural mechanisms mediating chromatic contextual interactions.

PubMed

D'Antona, Anthony D; Christiansen, Jens H; Shevell, Steven K

2014-04-17

When seen in isolation, a light that varies in chromaticity over time is perceived to oscillate in color. Perception of that same time-varying light may be altered by a surrounding light that is also temporally varying in chromaticity. The neural mechanisms that mediate these contextual interactions are the focus of this article. Observers viewed a central test stimulus that varied in chromaticity over time within a larger surround that also varied in chromaticity at the same temporal frequency. Center and surround were presented either to the same eye (monocular condition) or to opposite eyes (dichoptic condition) at the same frequency (3.125, 6.25, or 9.375 Hz). Relative phase between center and surround modulation was varied. In both the monocular and dichoptic conditions, the perceived modulation depth of the central light depended on the relative phase of the surround. A simple model implementing a linear combination of center and surround modulation fit the measurements well. At the lowest temporal frequency (3.125 Hz), the surround's influence was virtually identical for monocular and dichoptic conditions, suggesting that at this frequency, the surround's influence is mediated primarily by a binocular neural mechanism. At higher frequencies, the surround's influence was greater for the monocular condition than for the dichoptic condition, and this difference increased with temporal frequency. Our findings show that two separate neural mechanisms mediate chromatic contextual interactions: one binocular and dominant at lower temporal frequencies and the other monocular and dominant at higher frequencies (6-10 Hz).

Assessment of Low Cycle Fatigue Behavior of Powder Metallurgy Alloy U720

NASA Technical Reports Server (NTRS)

Gabb, Tomothy P.; Bonacuse, Peter J.; Ghosn, Louis J.; Sweeney, Joseph W.; Chatterjee, Amit; Green, Kenneth A.

2000-01-01

The fatigue lives of modem powder metallurgy disk alloys are influenced by variabilities in alloy microstructure and mechanical properties. These properties can vary as functions of variables the different steps of materials/component processing: powder atomization, consolidation, extrusion, forging, heat treating, and machining. It is important to understand the relationship between the statistical variations in life and these variables, as well as the change in life distribution due to changes in fatigue loading conditions. The objective of this study was to investigate these relationships in a nickel-base disk superalloy, U720, produced using powder metallurgy processing. Multiple strain-controlled fatigue tests were performed at 538 C (1000 F) at limited sets of test conditions. Analyses were performed to: (1) assess variations of microstructure, mechanical properties, and LCF failure initiation sites as functions of disk processing and loading conditions; and (2) compare mean and minimum fatigue life predictions using different approaches for modeling the data from assorted test conditions. Significant variations in life were observed as functions of the disk processing variables evaluated. However, the lives of all specimens could still be combined and modeled together. The failure initiation sites for tests performed at a strain ratio R(sub epsilon) = epsilon(sub min)/epsilon(sub max) of 0 were different from those in tests at a strain ratio of -1. An approach could still be applied to account for the differences in mean and maximum stresses and strains. This allowed the data in tests of various conditions to be combined for more robust statistical estimates of mean and minimum lives.

Assessment of variability in the hydrological cycle of the Loess Plateau, China: examining dependence structures of hydrological processes

NASA Astrophysics Data System (ADS)

Guo, A.; Wang, Y.

2017-12-01

Investigating variability in dependence structures of hydrological processes is of critical importance for developing an understanding of mechanisms of hydrological cycles in changing environments. In focusing on this topic, present work involves the following: (1) identifying and eliminating serial correlation and conditional heteroscedasticity in monthly streamflow (Q), precipitation (P) and potential evapotranspiration (PE) series using the ARMA-GARCH model (ARMA: autoregressive moving average; GARCH: generalized autoregressive conditional heteroscedasticity); (2) describing dependence structures of hydrological processes using partial copula coupled with the ARMA-GARCH model and identifying their variability via copula-based likelihood-ratio test method; and (3) determining conditional probability of annual Q under different climate scenarios on account of above results. This framework enables us to depict hydrological variables in the presence of conditional heteroscedasticity and to examine dependence structures of hydrological processes while excluding the influence of covariates by using partial copula-based ARMA-GARCH model. Eight major catchments across the Loess Plateau (LP) are used as study regions. Results indicate that (1) The occurrence of change points in dependence structures of Q and P (PE) varies across the LP. Change points of P-PE dependence structures in all regions almost fully correspond to the initiation of global warming, i.e., the early 1980s. (3) Conditional probabilities of annual Q under various P and PE scenarios are estimated from the 3-dimensional joint distribution of (Q, P and PE) based on the above change points. These findings shed light on mechanisms of the hydrological cycle and can guide water supply planning and management, particularly in changing environments.

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

Sevik, James; Pamminger, Michael; Wallner, Thomas

Interest in natural gas as an alternative fuel source to petroleum fuels for light-duty vehicle applications has increased due to its domestic availability and stable price compared to gasoline. With its higher hydrogen-to-carbon ratio, natural gas has the potential to reduce engine out carbon dioxide emissions, which has shown to be a strong greenhouse gas contributor. For part-load conditions, the lower flame speeds of natural gas can lead to an increased duration in the inflammation process with traditional port-injection. Direct-injection of natural gas can increase in-cylinder turbulence and has the potential to reduce problems typically associated with port-injection of naturalmore » gas, such as lower flame speeds and poor dilution tolerance. A study was designed and executed to investigate the effects of direct-injection of natural gas at part-load conditions. Steady-state tests were performed on a single-cylinder research engine representative of current gasoline direct-injection engines. Tests were performed with direct-injection in the central and side location. The start of injection was varied under stoichiometric conditions in order to study the effects on the mixture formation process. In addition, exhaust gas recirculation was introduced at select conditions in order to investigate the dilution tolerance. Relevant combustion metrics were then analyzed for each scenario. Experimental results suggest that regardless of the injector location, varying the start of injection has a strong impact on the mixture formation process. Delaying the start of injection from 300 to 120°CA BTDC can reduce the early flame development process by nearly 15°CA. While injecting into the cylinder after the intake valves have closed has shown to produce the fastest combustion process, this does not necessarily lead to the highest efficiency, due to increases in pumping and wall heat losses. When comparing the two injection configurations, the side location shows the best performance in terms of combustion metrics and efficiencies. For both systems, part-load dilution tolerance is affected by the injection timing, due to the induced turbulence from the gaseous injection event. CFD simulation results have shown that there is a fundamental difference in how the two injection locations affect the mixture formation process. Delayed injection timing increases the turbulence level in the cylinder at the time of the spark, but reduces the available time for proper mixing. Side injection delivers a gaseous jet that interacts more effectively with the intake induced flow field, and this improves the engine performance in terms of efficiency.« less

The Effects of Pre-processing Strategies for Pediatric Cochlear Implant Recipients

PubMed Central

Rakszawski, Bernadette; Wright, Rose; Cadieux, Jamie H.; Davidson, Lisa S.; Brenner, Christine

2016-01-01

Background Cochlear implants (CIs) have been shown to improve children’s speech recognition over traditional amplification when severe to profound sensorineural hearing loss is present. Despite improvements, understanding speech at low-level intensities or in the presence of background noise remains difficult. In an effort to improve speech understanding in challenging environments, Cochlear Ltd. offers pre-processing strategies that apply various algorithms prior to mapping the signal to the internal array. Two of these strategies include Autosensitivity Control™ (ASC) and Adaptive Dynamic Range Optimization (ADRO®). Based on previous research, the manufacturer’s default pre-processing strategy for pediatrics’ everyday programs combines ASC+ADRO®. Purpose The purpose of this study is to compare pediatric speech perception performance across various pre-processing strategies while applying a specific programming protocol utilizing increased threshold (T) levels to ensure access to very low-level sounds. Research Design This was a prospective, cross-sectional, observational study. Participants completed speech perception tasks in four pre-processing conditions: no pre-processing, ADRO®, ASC, ASC+ADRO®. Study Sample Eleven pediatric Cochlear Ltd. cochlear implant users were recruited: six bilateral, one unilateral, and four bimodal. Intervention Four programs, with the participants’ everyday map, were loaded into the processor with different pre-processing strategies applied in each of the four positions: no pre-processing, ADRO®, ASC, and ASC+ADRO®. Data Collection and Analysis Participants repeated CNC words presented at 50 and 70 dB SPL in quiet and HINT sentences presented adaptively with competing R-Space noise at 60 and 70 dB SPL. Each measure was completed as participants listened with each of the four pre-processing strategies listed above. Test order and condition were randomized. A repeated-measures analysis of variance (ANOVA) was used to compare each pre-processing strategy across group data. Critical differences were utilized to determine significant score differences between each pre-processing strategy for individual participants. Results For CNC words presented at 50 dB SPL, the group data revealed significantly better scores using ASC+ADRO® compared to all other pre-processing conditions while ASC resulted in poorer scores compared to ADRO® and ASC+ADRO®. Group data for HINT sentences presented in 70 dB SPL of R-Space noise revealed significantly improved scores using ASC and ASC+ADRO® compared to no pre-processing, with ASC+ADRO® scores being better than ADRO® alone scores. Group data for CNC words presented at 70 dB SPL and adaptive HINT sentences presented in 60 dB SPL of R-Space noise showed no significant difference among conditions. Individual data showed that the pre-processing strategy yielding the best scores varied across measures and participants. Conclusions Group data reveals an advantage with ASC+ADRO® for speech perception presented at lower levels and in higher levels of background noise. Individual data revealed that the optimal pre-processing strategy varied among participants; indicating that a variety of pre-processing strategies should be explored for each CI user considering his or her performance in challenging listening environments. PMID:26905529

PVDF-based semicrystalline-amorphous blends: Phase behavior and thermomechanical properties

NASA Astrophysics Data System (ADS)

Campo, Cheryl Josephine

Poly(vinylidene fluoride) [PVDF]-based semicrystalline-amorphous blends were studied to better understand the degree to which transition temperatures and mechanical properties could be varied as a function of composition. Changes in the amorphous component, processing parameters, MW, and filler content were used to manipulate blend properties. Compositional and MW series of PVDF:poly(vinyl acetate) [PVAc] blends were prepared and characterized. Varying PVDF content led to appreciable changes in crystallinity. In contrast, the effect of composition on blend glass transition temperature, Tg, was manifested only at low PVDF contents. The effect of MWPVA, on the 30:70 PVDF:PVAc composition was manifested primarily in the materials' viscoelastic response to deformation. Ternary blends of PVDF, PVAc, and poly(methyl methacrylate) [PMMA] showed limited miscibility with both a PVAc- and PMMA-rich amorphous phase apparent in all the compositions tested. PVDF:PMMA blends on the other hand exhibited good miscibility characterized by tunable Tg values which were further exploited by varying the processing conditions in order to obtain thermomechanical properties ideal for bio-related shape memory applications. PVDF:poly(ethyl methacrylate) [PEMA] blends, despite having very broad transitions, similarly exhibited desirable transition temperatures for in vivo actuation. The effect of boron nitride (BN), short carbon fibers (SCF), and clay on blend properties was also assessed. SCF filler in 50:50 PVDF:PMMA led mainly to the formation of PVDF crystals in the alpha form, clay was observed to promote growth of the beta crystal form, and BN led to a mixture of crystal forms. BN also exhibited interesting effects in the creep behavior of this system as well as the crystallization behavior of the 50:50 PVDF:PEMA blend, suppressed kinetic crystallization competing with enhanced nucleation effect under isothermal conditions observed in the latter. Depending on the processing conditions used, SCF was found to have similar nucleation effects in the 50:50 PVDF:PMMA blend but diminished degrees of crystallinity overall. Finally, shape memory behavior of PVDF:PVAc blends as well as SCF-filled 50:50 PVDF:PMMA was characterized using single and multiple shape memory cycles. Increasing PVDF content had a negative impact on PVDF:PVAc shape memory properties while increasing stress was found to have an enhancing effect as did low SCF filler content in 50:50 PVDF:PMMA.

Prolegomena to the Study of Friction Stir Welding

NASA Technical Reports Server (NTRS)

Nunes, Arthur C., Jr.

2010-01-01

The literature contains many approaches toward modeling of the friction stir welding (FSW) process with varying treatments of the weld metal properties. It is worthwhile to consider certain fundamental features of the process before attempting to interpret FSW phenomena: Because of the unique character of metal deformation (as opposed to, say, viscous deformation) a velocity "discontinuity" or shear surface occurs in FSW and determines much of the character of the welding mechanism. A shear surface may not always produce a sound bond. Balancing mechanical power input against conduction and convection heat losses yields a relation, a "temperature index", between spindle speed and travel speed to maintain constant weld temperature. But many process features are only weakly dependent upon temperature. Thus, unlike modeling of metal forming processes, it may be that modeling the FSW process independently of the material conditions has some merit.

Spatially-varied erosion modeling using WEPP for timber harvested and burned hillslopes

Treesearch

Peter R. Robichaud; T. M. Monroe

1997-01-01

Spatially-varied hydrologic surface conditions exist on steep hillslopes after timber harvest operation and site preparation burning treatments. Site preparation burning creates low- and high-severity burn surface conditions or disturbances. In this study, a hillslope was divided into multiple combinations of surface conditions to determine how their spatial...

Wear Properties of ECAP-Processed AM80 Magnesium Alloy

NASA Astrophysics Data System (ADS)

Gopi, K. R.; Shivananda Nayaka, H.; Sahu, Sandeep

2017-07-01

AM80 magnesium alloy was subjected to equal-channel angular pressing (ECAP), and microstructural evolution was studied using scanning electron microscope (SEM). Grain size was found to decrease up to 3 µm after four passes. An increase in number of ECAP passes led to a corresponding increase in hardness of the processed samples. Unprocessed and ECAP-processed samples were subjected to wear test using pin-on-disk wear test machine to study the wear behavior. Effects of varying loads (30 and 40 N) with sliding distances (2500 and 5000 m) were studied. The results showed reduction in wear mass loss for the ECAP-processed samples in comparison with unprocessed condition. Coefficient of friction (COF) was studied for different loads, and improvement in COF values was observed for ECAP-processed samples compared to unprocessed condition. Worn surfaces were studied using SEM and energy-dispersive x-ray spectrometer, and they exhibited plastic deformation, delamination, plowing, wear debris and oxidation in the sliding direction. X-ray diffraction analysis was conducted on the worn surfaces to identify the phases. It revealed the presence of magnesium oxide and magnesium aluminum oxide which led to oxidation wear in the sliding direction. Wear mechanism was found to be abrasive and oxidation wear.

Enhanced Impurity-Free Intermixing Bandgap Engineering for InP-Based Photonic Integrated Circuits

NASA Astrophysics Data System (ADS)

Cui, Xiao; Zhang, Can; Liang, Song; Zhu, Hong-Liang; Hou, Lian-Ping

2014-04-01

Impurity-free intermixing of InGaAsP multiple quantum wells (MQW) using sputtering Cu/SiO2 layers followed by rapid thermal processing (RTP) is demonstrated. The bandgap energy could be modulated by varying the sputtering power and time of Cu, RTP temperature and time to satisfy the demands for lasers, modulators, photodetector, and passive waveguides for the photonic integrated circuits with a simple procedure. The blueshift of the bandgap wavelength of MQW is experimentally investigated on different sputtering and annealing conditions. It is obvious that the introduction of the Cu layer could increase the blueshift more greatly than the common impurity free vacancy disordering technique. A maximum bandgap blueshift of 172 nm is realized with an annealing condition of 750°C and 200s. The improved technique is promising for the fabrication of the active/passive optoelectronic components on a single wafer with simple process and low cost.

State-dependent sensorimotor processing: gaze and posture stability during simulated flight in birds.

PubMed

McArthur, Kimberly L; Dickman, J David

2011-04-01

Vestibular responses play an important role in maintaining gaze and posture stability during rotational motion. Previous studies suggest that these responses are state dependent, their expression varying with the environmental and locomotor conditions of the animal. In this study, we simulated an ethologically relevant state in the laboratory to study state-dependent vestibular responses in birds. We used frontal airflow to simulate gliding flight and measured pigeons' eye, head, and tail responses to rotational motion in darkness, under both head-fixed and head-free conditions. We show that both eye and head response gains are significantly higher during flight, thus enhancing gaze and head-in-space stability. We also characterize state-specific tail responses to pitch and roll rotation that would help to maintain body-in-space orientation during flight. These results demonstrate that vestibular sensorimotor processing is not fixed but depends instead on the animal's behavioral state.

State-dependent sensorimotor processing: gaze and posture stability during simulated flight in birds

PubMed Central

McArthur, Kimberly L.

2011-01-01

Vestibular responses play an important role in maintaining gaze and posture stability during rotational motion. Previous studies suggest that these responses are state dependent, their expression varying with the environmental and locomotor conditions of the animal. In this study, we simulated an ethologically relevant state in the laboratory to study state-dependent vestibular responses in birds. We used frontal airflow to simulate gliding flight and measured pigeons′ eye, head, and tail responses to rotational motion in darkness, under both head-fixed and head-free conditions. We show that both eye and head response gains are significantly higher during flight, thus enhancing gaze and head-in-space stability. We also characterize state-specific tail responses to pitch and roll rotation that would help to maintain body-in-space orientation during flight. These results demonstrate that vestibular sensorimotor processing is not fixed but depends instead on the animal's behavioral state. PMID:21307332

A comparison of acoustic levitation with microgravity processing for containerless solidification of ternary Al-Cu-Sn alloy

NASA Astrophysics Data System (ADS)

Yan, N.; Hong, Z. Y.; Geng, D. L.; Wei, B.

2015-07-01

The containerless rapid solidification of liquid ternary Al-5 %Cu-65 %Sn immiscible alloy was accomplished at both ultrasonic levitation and free fall conditions. A maximum undercooling of 185 K (0.22 T L) was obtained for the ultrasonically levitated alloy melt at a cooling rate of about 122 K s-1. Meanwhile, the cooling rate of alloy droplets in drop tube varied from 102 to 104 K s-1. The macrosegregation was effectively suppressed through the complex melt flow under ultrasonic levitation condition. In contrast, macrosegregation became conspicuous and core-shell structures with different layers were formed during free fall. The microstructure formation mechanisms during rapid solidification at containerless states were investigated in comparison with the conventional static solidification process. It was found that the liquid phase separation and structural growth kinetics may be modulated by controlling both alloy undercooling and cooling rate.

Studies on the Evaluation Methods for the Food Quality with a Non-contact type Capacitance Sensor.

NASA Astrophysics Data System (ADS)

Narumiya, Tadaoki; Hagura, Yoshio

Changes of capacitance and temperature of ethyl alcohol, hamburger and dough with cheese filling were measured with specially-made measuring devices during the freezing and thawing. The results of measurement of capacitance and temperature suggest a linear correlation for ethyl alcohol as a single constituent substance. The adequate correlation is too estimated from the results of food samples, though the capacitance of food sample varies greatly at the start and end of freezing and thawing process. It has been demonstrated that the quality or physical condition of food sample can be determined easily by the measurement of capacitance using the specially-made devices. Also the quality or physical condition of food can be determined easily by the non-contact and non-destructive measurements of capacitance. A variety application of the present technique is conceivable for the process control of the freezing and thawing foods.

Cultural differences in emotion regulation during self-reflection on negative personal experiences.

PubMed

Tsai, William; Lau, Anna S

2013-01-01

Reflecting on negative personal experiences has implications for mood that may vary as a function of specific domains (e.g., achievement vs. interpersonal) and cultural orientation (e.g., interdependence vs. independence). This study investigated cultural differences in the social-cognitive and affective processes undertaken as Easterners and Westerners reflected on negative interpersonal and performance experiences. One hundred Asian Americans and 92 European-American college students were randomly assigned to one of three conditions: interpersonal rejection, achievement failure, or a control condition. Results revealed that Asian Americans experienced greater distress than European Americans after self-reflecting over a failed interpersonal experience, suggesting cultural sensitivity in the relational domain. Consistent with theoretical predictions, analysis of the social cognitive and affective processes that participants engaged in during self-reflection provided some evidence that self-enhancement may buffer distress for European Americans, while emotion suppression may be adaptive for Asian Americans.

Experimental study of the visible-light photocatalytic activity of oxygen-deficient TiO2 prepared with Ar/H2 plasma surface treatment

NASA Astrophysics Data System (ADS)

Nakano, Takuma; Yazawa, Shota; Araki, Shota; Kogoshi, Sumio; Katayama, Noboru; Kudo, Yusuke; Nakanishi, Tetsuya

2015-01-01

Oxygen-deficient TiO2 (TiO2-x) has been proposed as a visible-light-responsive photocatalyst. TiO2-x thin films were prepared by Ar/H2 plasma surface treatment, applying varying levels of microwave input power and processing times. The highest visible light photocatalytic activity was observed when using an input power of 200 W, a plasma processing time of 10 min, and a 1:1 \\text{Ar}:\\text{H}2 ratio, conditions that generate an electron temperature of 5.7(±1.0) eV and an electron density of 8.5 × 1010 cm-3. The maximum formaldehyde (HCHO) removal rate of the TiO2-x film was 2.6 times higher than that obtained from a TiO2-xNx film under the same test conditions.

The effects of limited bandwidth and noise on verbal processing time and word recall in normal-hearing children.

PubMed

McCreery, Ryan W; Stelmachowicz, Patricia G

2013-09-01

Understanding speech in acoustically degraded environments can place significant cognitive demands on school-age children who are developing the cognitive and linguistic skills needed to support this process. Previous studies suggest the speech understanding, word learning, and academic performance can be negatively impacted by background noise, but the effect of limited audibility on cognitive processes in children has not been directly studied. The aim of the present study was to evaluate the impact of limited audibility on speech understanding and working memory tasks in school-age children with normal hearing. Seventeen children with normal hearing between 6 and 12 years of age participated in the present study. Repetition of nonword consonant-vowel-consonant stimuli was measured under conditions with combinations of two different signal to noise ratios (SNRs; 3 and 9 dB) and two low-pass filter settings (3.2 and 5.6 kHz). Verbal processing time was calculated based on the time from the onset of the stimulus to the onset of the child's response. Monosyllabic word repetition and recall were also measured in conditions with a full bandwidth and 5.6 kHz low-pass cutoff. Nonword repetition scores decreased as audibility decreased. Verbal processing time increased as audibility decreased, consistent with predictions based on increased listening effort. Although monosyllabic word repetition did not vary between the full bandwidth and 5.6 kHz low-pass filter condition, recall was significantly poorer in the condition with limited bandwidth (low pass at 5.6 kHz). Age and expressive language scores predicted performance on word recall tasks, but did not predict nonword repetition accuracy or verbal processing time. Decreased audibility was associated with reduced accuracy for nonword repetition and increased verbal processing time in children with normal hearing. Deficits in free recall were observed even under conditions where word repetition was not affected. The negative effects of reduced audibility may occur even under conditions where speech repetition is not impacted. Limited stimulus audibility may result in greater cognitive effort for verbal rehearsal in working memory and may limit the availability of cognitive resources to allocate to working memory and other processes.

User's guide to the Variably Saturated Flow (VSF) process to MODFLOW

USGS Publications Warehouse

Thoms, R. Brad; Johnson, Richard L.; Healy, Richard W.

2006-01-01

A new process for simulating three-dimensional (3-D) variably saturated flow (VSF) using Richards' equation has been added to the 3-D modular finite-difference ground-water model MODFLOW. Five new packages are presented here as part of the VSF Process--the Richards' Equation Flow (REF1) Package, the Seepage Face (SPF1) Package, the Surface Ponding (PND1) Package, the Surface Evaporation (SEV1) Package, and the Root Zone Evapotranspiration (RZE1) Package. Additionally, a new Adaptive Time-Stepping (ATS1) Package is presented for use by both the Ground-Water Flow (GWF) Process and VSF. The VSF Process allows simulation of flow in unsaturated media above the ground-water zone and facilitates modeling of ground-water/surface-water interactions. Model performance is evaluated by comparison to an analytical solution for one-dimensional (1-D) constant-head infiltration (Dirichlet boundary condition), field experimental data for a 1-D constant-head infiltration, laboratory experimental data for two-dimensional (2-D) constant-flux infiltration (Neumann boundary condition), laboratory experimental data for 2-D transient drainage through a seepage face, and numerical model results (VS2DT) of a 2-D flow-path simulation using realistic surface boundary conditions. A hypothetical 3-D example case also is presented to demonstrate the new capability using periodic boundary conditions (for example, daily precipitation) and varied surface topography over a larger spatial scale (0.133 square kilometer). The new model capabilities retain the modular structure of the MODFLOW code and preserve MODFLOW's existing capabilities as well as compatibility with commercial pre-/post-processors. The overall success of the VSF Process in simulating mixed boundary conditions and variable soil types demonstrates its utility for future hydrologic investigations. This report presents a new flow package implementing the governing equations for variably saturated ground-water flow, four new boundary condition packages unique to unsaturated flow, the Adaptive Time-Stepping Package for use with both the GWF Process and the new VSF Process, detailed descriptions of the input and output files for each package, and six simulation examples verifying model performance.

Quantifying in-stream nitrate reaction rates using continuously-collected water quality data

Treesearch

Matthew Miller; Anthony Tesoriero; Paul Capel

2016-01-01

High frequency in situ nitrate data from three streams of varying hydrologic condition, land use, and watershed size were used to quantify the mass loading of nitrate to streams from two sources – groundwater discharge and event flow – at a daily time step for one year. These estimated loadings were used to quantify temporally-variable in-stream nitrate processing ...

Methods for predicting properties and tailoring salt solutions for industrial processes

NASA Technical Reports Server (NTRS)

Ally, Moonis R.

1993-01-01

An algorithm developed at Oak Ridge National Laboratory accurately and quickly predicts thermodynamic properties of concentrated aqueous salt solutions. This algorithm is much simpler and much faster than other modeling schemes and is unique because it can predict solution behavior at very high concentrations and under varying conditions. Typical industrial applications of this algorithm would be in manufacture of inorganic chemicals by crystallization, thermal storage, refrigeration and cooling, extraction of metals, emissions controls, etc.

Fuel Effects on Nozzle Flow and Spray Using Fully Coupled Eulerian Simulations

DTIC Science & Technology

2015-09-01

Density of liquid fuel, kg/m 3 = Density of ambient gas , kg/m 3 VOF = Volume of Fluid model = Volume of Fluid Scalar ROI = Rate of...have been reported arising from individual refinery processes, crude oil source, and also varying with season, year and age of the fuel. This myriad...configurations. Under reacting conditions, Violi et al. (6) presented a surrogate mixture of six pure hydrocarbon ( Utah surrogate) and found that it

Gas Diffusion in Fluids Containing Bubbles

NASA Technical Reports Server (NTRS)

Zak, M.; Weinberg, M. C.

1982-01-01

Mathematical model describes movement of gases in fluid containing many bubbles. Model makes it possible to predict growth and shrink age of bubbles as function of time. New model overcomes complexities involved in analysis of varying conditions by making two simplifying assumptions. It treats bubbles as point sources, and it employs approximate expression for gas concentration gradient at liquid/bubble interface. In particular, it is expected to help in developing processes for production of high-quality optical glasses in space.

Effects of sensorineural hearing loss on temporal coding of narrowband and broadband signals in the auditory periphery

PubMed Central

Henry, Kenneth S.; Heinz, Michael G.

2013-01-01

People with sensorineural hearing loss have substantial difficulty understanding speech under degraded listening conditions. Behavioral studies suggest that this difficulty may be caused by changes in auditory processing of the rapidly-varying temporal fine structure (TFS) of acoustic signals. In this paper, we review the presently known effects of sensorineural hearing loss on processing of TFS and slower envelope modulations in the peripheral auditory system of mammals. Cochlear damage has relatively subtle effects on phase locking by auditory-nerve fibers to the temporal structure of narrowband signals under quiet conditions. In background noise, however, sensorineural loss does substantially reduce phase locking to the TFS of pure-tone stimuli. For auditory processing of broadband stimuli, sensorineural hearing loss has been shown to severely alter the neural representation of temporal information along the tonotopic axis of the cochlea. Notably, auditory-nerve fibers innervating the high-frequency part of the cochlea grow increasingly responsive to low-frequency TFS information and less responsive to temporal information near their characteristic frequency (CF). Cochlear damage also increases the correlation of the response to TFS across fibers of varying CF, decreases the traveling-wave delay between TFS responses of fibers with different CFs, and can increase the range of temporal modulation frequencies encoded in the periphery for broadband sounds. Weaker neural coding of temporal structure in background noise and degraded coding of broadband signals along the tonotopic axis of the cochlea are expected to contribute considerably to speech perception problems in people with sensorineural hearing loss. PMID:23376018

All-in-one centrifugal microfluidic device for size-selective circulating tumor cell isolation with high purity.

PubMed

Lee, Ada; Park, Juhee; Lim, Minji; Sunkara, Vijaya; Kim, Shine Young; Kim, Gwang Ha; Kim, Mi-Hyun; Cho, Yoon-Kyoung

2014-11-18

Circulating tumor cells (CTCs) have gained increasing attention owing to their roles in cancer recurrence and progression. Due to the rarity of CTCs in the bloodstream, an enrichment process is essential for effective target cell characterization. However, in a typical pressure-driven microfluidic system, the enrichment process generally requires complicated equipment and long processing times. Furthermore, the commonly used immunoaffinity-based positive selection method is limited, as its recovery rate relies on EpCAM expression of target CTCs, which shows heterogeneity among cell types. Here, we propose a centrifugal-force-based size-selective CTC isolation platform that can isolate and enumerate CTCs from whole blood within 30 s with high purity. The device was validated using the MCF-7 breast cancer cell line spiked in phosphate-buffered saline and whole blood, and an average capture efficiency of 61% was achieved, which is typical for size-based filtration. The capture efficiency for whole blood samples varied from 44% to 84% under various flow conditions and dilution factors. Under the optimized operating conditions, a few hundred white blood cells per 1 mL of whole blood were captured, representing a 20-fold decrease compared to those obtained using a commercialized size-based CTC isolation device. In clinical validation, normalized CTC counts varied from 10 to 60 per 7.5 mL of blood from gastric and lung cancer patients, yielding a detection rate of 50% and 38%, respectively. Overall, our CTC isolation device enables rapid and label-free isolation of CTCs with high purity, which should greatly improve downstream molecular analyses of captured CTCs.

Model Improvement by Assimilating Observations of Storm-Induced Coastal Change

NASA Astrophysics Data System (ADS)

Long, J. W.; Plant, N. G.; Sopkin, K.

2010-12-01

Discrete, large scale, meteorological events such as hurricanes can cause wide-spread destruction of coastal islands, habitats, and infrastructure. The effects can vary significantly along the coast depending on the configuration of the coastline, variable dune elevations, changes in geomorphology (sandy beach vs. marshland), and alongshore variations in storm hydrodynamic forcing. There are two primary methods of determining the changing state of a coastal system. Process-based numerical models provide highly resolved (in space and time) representations of the dominant dynamics in a physical system but must employ certain parameterizations due to computational limitations. The predictive capability may also suffer from the lack of reliable initial or boundary conditions. On the other hand, observations of coastal topography before and after the storm allow the direct quantification of cumulative storm impacts. Unfortunately these measurements suffer from instrument noise and a lack of necessary temporal resolution. This research focuses on the combination of these two pieces of information to make more reliable forecasts of storm-induced coastal change. Of primary importance is the development of a data assimilation strategy that is efficient, applicable for use with highly nonlinear models, and able to quantify the remaining forecast uncertainty based on the reliability of each individual piece of information used in the assimilation process. We concentrate on an event time-scale and estimate/update unobserved model information (boundary conditions, free parameters, etc.) by assimilating direct observations of coastal change with those simulated by the model. The data assimilation can help estimate spatially varying quantities (e.g. friction coefficients) that are often modeled as homogeneous and identify processes inadequately characterized in the model.

Importance of associative learning processes for one-trial behavioral sensitization of preweanling rats.

PubMed

McDougall, Sanders A; Pothier, Alexandria G; Der-Ghazarian, Taleen; Herbert, Matthew S; Kozanian, Olga O; Castellanos, Kevin A; Flores, Ana T

2011-10-01

During adulthood, associative learning is necessary for the expression of one-trial behavioral sensitization; however, it is uncertain whether the same associative processes are operative during the preweanling period. Two strategies were used to assess the importance of associative learning for one-trial behavioral sensitization of preweanling rats. In the initial experiments, we varied both the sequence and time interval between presentation of the conditioned stimulus (CS, novel environment) and unconditioned stimulus (US, cocaine). In the final experiment, we determined whether electroconvulsive shock-induced retrograde amnesia would disrupt one-trial behavioral sensitization. Results showed that robust-sensitized responding was apparent regardless of the sequence in which cocaine and the novel environment (the presumptive CS) were presented. Varying the time between CS and US presentation (0, 3, or 6 h) was also without effect. Results from experiment 3 showed that single or multiple electroconvulsive shock treatments did not alter the expression of the sensitized response. Therefore, these data indicated that one-trial behavioral sensitization of preweanling rats was exclusively mediated by nonassociative mechanisms and that associative processes did not modulate sensitized responding. These findings are in contrast to what is observed during adulthood, as adult rats exhibit one-trial behavioral sensitization only when associative processes are operative.

Monitoring copper release in drinking water distribution systems.

PubMed

d'Antonio, L; Fabbricino, M; Panico, A

2008-01-01

A new procedure, recently proposed for on-line monitoring of copper released from metal pipes in household plumbing system for drinking water distribution during the development of corrosion processes, is tested experimentally. Experiments were carried out in laboratory controlled conditions, using synthetic water and varying the water alkalinity. The possibility of using the corrosion potential as a surrogate measure of copper concentration in stagnating water is shown, verifying, in the meantime, the effect of alkalinity on the development of passivation phenomena, which tend to protect the pipe from corrosion processes. Experimental data are discussed, highlighting the potentiality of the procedure, and recognizing its limitations. Copyright IWA Publishing 2008.

Dynamic metrology and data processing for precision freeform optics fabrication and testing

NASA Astrophysics Data System (ADS)

Aftab, Maham; Trumper, Isaac; Huang, Lei; Choi, Heejoo; Zhao, Wenchuan; Graves, Logan; Oh, Chang Jin; Kim, Dae Wook

2017-06-01

Dynamic metrology holds the key to overcoming several challenging limitations of conventional optical metrology, especially with regards to precision freeform optical elements. We present two dynamic metrology systems: 1) adaptive interferometric null testing; and 2) instantaneous phase shifting deflectometry, along with an overview of a gradient data processing and surface reconstruction technique. The adaptive null testing method, utilizing a deformable mirror, adopts a stochastic parallel gradient descent search algorithm in order to dynamically create a null testing condition for unknown freeform optics. The single-shot deflectometry system implemented on an iPhone uses a multiplexed display pattern to enable dynamic measurements of time-varying optical components or optics in vibration. Experimental data, measurement accuracy / precision, and data processing algorithms are discussed.

Transcriptional dynamics with time-dependent reaction rates

NASA Astrophysics Data System (ADS)

Nandi, Shubhendu; Ghosh, Anandamohan

2015-02-01

Transcription is the first step in the process of gene regulation that controls cell response to varying environmental conditions. Transcription is a stochastic process, involving synthesis and degradation of mRNAs, that can be modeled as a birth-death process. We consider a generic stochastic model, where the fluctuating environment is encoded in the time-dependent reaction rates. We obtain an exact analytical expression for the mRNA probability distribution and are able to analyze the response for arbitrary time-dependent protocols. Our analytical results and stochastic simulations confirm that the transcriptional machinery primarily act as a low-pass filter. We also show that depending on the system parameters, the mRNA levels in a cell population can show synchronous/asynchronous fluctuations and can deviate from Poisson statistics.

Growth kinetics of physical vapor transport processes: Crystal growth of the optoelectronic material mercurous chloride

NASA Technical Reports Server (NTRS)

Singh, N. B.; Duval, W. M.

1991-01-01

Physical vapor transport processes were studied for the purpose of identifying the magnitude of convective effects on the crystal growth process. The effects of convection on crystal quality were were studied by varying the aspect ratio and those thermal conditions which ultimately affect thermal convection during physical vapor transport. An important outcome of the present study was the observation that the convection growth rate increased up to a certain value and then dropped to a constant value for high aspect ratios. This indicated that a very complex transport had occurred which could not be explained by linear stability theory. Better quality crystals grown at a low Rayleigh number confirmed that improved properties are possible in convectionless environments.

Eye movements show similar adaptations in temporal coordination to movement planning conditions in both people with and without cerebral palsy.

PubMed

Payne, Alexander R; Plimmer, Beryl; McDaid, Andrew; Davies, T Claire

2017-05-01

The effects of cerebral palsy on movement planning for simple reaching tasks are not well understood. Movement planning is complex and entails many processes which could be affected. This study specifically sought to evaluate integrating task information, decoupling movements, and adjusting to altered mapping. For a reaching task, the asynchrony between the eye onset and the hand onset was measured across different movement planning conditions for participants with and without cerebral palsy. Previous research shows people without cerebral palsy vary this temporal coordination for different planning conditions. Our measurements show similar adaptations in temporal coordination for groups with and without cerebral palsy, to three of the four variations in planning condition tested. However, movement durations were still longer for the participants with cerebral palsy. Hence for simple goal-directed reaching, movement execution problems appear to limit activity more than movement planning deficits.

What is the cause of confidence inflation in the Life Events Inventory (LEI) paradigm?

PubMed

Von Glahn, Nicholas R; Otani, Hajime; Migita, Mai; Langford, Sara J; Hillard, Erin E

2012-01-01

Briefly imagining, paraphrasing, or explaining an event causes people to increase their confidence that this event occurred during childhood-the imagination inflation effect. The mechanisms responsible for the effect were investigated with a new paradigm. In Experiment 1, event familiarity (defined as processing fluency) was varied by asking participants to rate each event once, three times, or five times. No inflation was found, indicating that familiarity does not account for the effect. In Experiment 2, richness of memory representation was manipulated by asking participants to generate zero, three, or six details. Confidence increased from the initial to the final rating in the three- and six-detail conditions, indicating that the effect is based on reality-monitoring errors. However, greater inflation in the three-detail condition than in the six-detail condition indicated that there is a boundary condition. These results were also consistent with an alternative hypothesis, the mental workload hypothesis.

The influence of cognitive ability and instructional set on causal conditional inference.

PubMed

Evans, Jonathan St B T; Handley, Simon J; Neilens, Helen; Over, David

2010-05-01

We report a large study in which participants are invited to draw inferences from causal conditional sentences with varying degrees of believability. General intelligence was measured, and participants were split into groups of high and low ability. Under strict deductive-reasoning instructions, it was observed that higher ability participants were significantly less influenced by prior belief than were those of lower ability. This effect disappeared, however, when pragmatic reasoning instructions were employed in a separate group. These findings are in accord with dual-process theories of reasoning. We also took detailed measures of beliefs in the conditional sentences used for the reasoning tasks. Statistical modelling showed that it is not belief in the conditional statement per se that is the causal factor, but rather correlates of it. Two different models of belief-based reasoning were found to fit the data according to the kind of instructions and the type of inference under consideration.

Helicobacter pylori colonization critically depends on postprandial gastric conditions

PubMed Central

Bücker, Roland; Azevedo-Vethacke, Marina; Groll, Claudia; Garten, Désirée; Josenhans, Christine; Suerbaum, Sebastian; Schreiber, Sören

2012-01-01

The risk of Helicobacter pylori infection is highest in childhood, but the colonization process of the stomach mucosa is poorly understood. We used anesthetized Mongolian gerbils to study the initial stages of H. pylori colonization. Prandial and postprandial gastric conditions characteristic of humans of different ages were simulated. The fraction of bacteria that reached the deep mucus layer varied strongly with the modelled postprandial conditions. Colonization success was weak with fast gastric reacidification typical of adults. The efficiency of deep mucus entry was also low with a slow pH decrease as seen in pH profiles simulating the situation in babies. Initial colonization was most efficient under conditions simulating the postprandial reacidification and pepsin activation profiles in young children. In conclusion, initial H. pylori colonization depends on age-related gastric physiology, providing evidence from an in vivo infection model that suggests an explanation why the bacterium is predominantly acquired in early childhood. PMID:23251780

Roundness and taper of holes during drilling composites of various thickness by HSS drill bit under dry condition

NASA Astrophysics Data System (ADS)

Sakib, M. S.; Rahman, Motiur; Ferdous, M.; Dhar, N. R.

2017-12-01

Polymer Matrix Composites are extending a wide range of applications in aviation in recent eras because of their better economics, well established processing, high temperature properties, high resistance to corrosion and fatigue. Directional properties of composites are dependent on the fibre orientation. Composites being anisotropic in nature are difficult to drill and machining and tooling of the composites remained a great challenge over time. This paper addresses the issues of various machining problems such as delamination, fibre pull-out, cracks on varying drilling parameters like feed rate and drilling speed. Experimental drilling was carried out on Fibre Reinforced Plastic composites with HSS drill bit. Results reveal that as the number of holes increases the entry and exit diameter and tapper of holes vary and also varying composite thickness results in a difference in hole roundness and tapper. This experiment summarizes that for achieving acceptable tool life and hole quality demands a drill designed with composites.

MAVEN - Mars Atmosphere and Volatile EvolutioN Mission

NASA Technical Reports Server (NTRS)

Grebowsky, Joseph M.; Jakosky, Bruce M.

2011-01-01

NASA's MAVEN mission (to be launched in late 2013) is the first mission to Mars devoted to sampling all of the upper atmosphere neutral and plasma environments, including the well-mixed atmosphere, the exosphere, ionosphere, outer magnetosphere and near-Mars solar wind. It will fill in some measurement gaps remaining from the successful Mars Global Surveyor and the on-going Mars Express missions. The primary science objectives of MAVEN are: 1. Provide a comprehensive picture of the present state of the upper atmosphere and ionosphere of Mars; 2. Understand the processes controlling the present state; and 3. Determine how loss of volatiles to outer space in the present epoch varies with changing solar condition - EUY, solar wind and interplanetary magnetic field measurements will provide the varying solar energy inputs into the system. Knowing how these processes respond to the Sun's energy inputs in the current epoch will provide a framework for projecting atmospheric processes back in time to profile MARS' atmospheric evolution and to explore "where the water went", A description will be given of the science objectives, the instruments, and the current status of the project, emphasizing the value of having collaborations between the MAVEN project and the Mars upper atmosphere science community.

Universal Rim Thickness in Unsteady Sheet Fragmentation.

PubMed

Wang, Y; Dandekar, R; Bustos, N; Poulain, S; Bourouiba, L

2018-05-18

Unsteady fragmentation of a fluid bulk into droplets is important for epidemiology as it governs the transport of pathogens from sneezes and coughs, or from contaminated crops in agriculture. It is also ubiquitous in industrial processes such as paint, coating, and combustion. Unsteady fragmentation is distinct from steady fragmentation on which most theoretical efforts have been focused thus far. We address this gap by studying a canonical unsteady fragmentation process: the breakup from a drop impact on a finite surface where the drop fluid is transferred to a free expanding sheet of time-varying properties and bounded by a rim of time-varying thickness. The continuous rim destabilization selects the final spray droplets, yet this process remains poorly understood. We combine theory with advanced image analysis to study the unsteady rim destabilization. We show that, at all times, the rim thickness is governed by a local instantaneous Bond number equal to unity, defined with the instantaneous, local, unsteady rim acceleration. This criterion is found to be robust and universal for a family of unsteady inviscid fluid sheet fragmentation phenomena, from impacts of drops on various surface geometries to impacts on films. We discuss under which viscous and viscoelastic conditions the criterion continues to govern the unsteady rim thickness.

Universal Rim Thickness in Unsteady Sheet Fragmentation

NASA Astrophysics Data System (ADS)

Wang, Y.; Dandekar, R.; Bustos, N.; Poulain, S.; Bourouiba, L.

2018-05-01

Unsteady fragmentation of a fluid bulk into droplets is important for epidemiology as it governs the transport of pathogens from sneezes and coughs, or from contaminated crops in agriculture. It is also ubiquitous in industrial processes such as paint, coating, and combustion. Unsteady fragmentation is distinct from steady fragmentation on which most theoretical efforts have been focused thus far. We address this gap by studying a canonical unsteady fragmentation process: the breakup from a drop impact on a finite surface where the drop fluid is transferred to a free expanding sheet of time-varying properties and bounded by a rim of time-varying thickness. The continuous rim destabilization selects the final spray droplets, yet this process remains poorly understood. We combine theory with advanced image analysis to study the unsteady rim destabilization. We show that, at all times, the rim thickness is governed by a local instantaneous Bond number equal to unity, defined with the instantaneous, local, unsteady rim acceleration. This criterion is found to be robust and universal for a family of unsteady inviscid fluid sheet fragmentation phenomena, from impacts of drops on various surface geometries to impacts on films. We discuss under which viscous and viscoelastic conditions the criterion continues to govern the unsteady rim thickness.

Temporal expectancy in the context of a theory of visual attention.

PubMed

Vangkilde, Signe; Petersen, Anders; Bundesen, Claus

2013-10-19

Temporal expectation is expectation with respect to the timing of an event such as the appearance of a certain stimulus. In this paper, temporal expectancy is investigated in the context of the theory of visual attention (TVA), and we begin by summarizing the foundations of this theoretical framework. Next, we present a parametric experiment exploring the effects of temporal expectation on perceptual processing speed in cued single-stimulus letter recognition with unspeeded motor responses. The length of the cue-stimulus foreperiod was exponentially distributed with one of six hazard rates varying between blocks. We hypothesized that this manipulation would result in a distinct temporal expectation in each hazard rate condition. Stimulus exposures were varied such that both the temporal threshold of conscious perception (t0 ms) and the perceptual processing speed (v letters s(-1)) could be estimated using TVA. We found that the temporal threshold t0 was unaffected by temporal expectation, but the perceptual processing speed v was a strikingly linear function of the logarithm of the hazard rate of the stimulus presentation. We argue that the effects on the v values were generated by changes in perceptual biases, suggesting that our perceptual biases are directly related to our temporal expectations.

Lane-changing model with dynamic consideration of driver's propensity

NASA Astrophysics Data System (ADS)

Wang, Xiaoyuan; Wang, Jianqiang; Zhang, Jinglei; Ban, Xuegang Jeff

2015-07-01

Lane-changing is the driver's selection result of the satisfaction degree in different lane driving conditions. There are many different factors influencing lane-changing behavior, such as diversity, randomicity and difficulty of measurement. So it is hard to accurately reflect the uncertainty of drivers' lane-changing behavior. As a result, the research of lane-changing models is behind that of car-following models. Driver's propensity is her/his emotion state or the corresponding preference of a decision or action toward the real objective traffic situations under the influence of various dynamic factors. It represents the psychological characteristics of the driver in the process of vehicle operation and movement. It is an important factor to influence lane-changing. In this paper, dynamic recognition of driver's propensity is considered during simulation based on its time-varying discipline and the analysis of the driver's psycho-physic characteristics. The Analytic Hierarchy Process (AHP) method is used to quantify the hierarchy of driver's dynamic lane-changing decision-making process, especially the influence of the propensity. The model is validated using real data. Test results show that the developed lane-changing model with the dynamic consideration of a driver's time-varying propensity and the AHP method are feasible and with improved accuracy.

Electrolyte-stimulated biphasic dissolution profile and stability enhancement for tablets containing drug-polyelectrolyte complexes.

PubMed

Kindermann, Christoph; Matthée, Karin; Sievert, Frank; Breitkreutz, Jörg

2012-10-01

Recently introduced drug-polyelectrolyte complexes prepared by hot-melt extrusion should be processed to solid dosage forms with tailor-made release properties. Their potential of stability enhancement should be investigated. Milled hot-melt extruded naproxen-EUDRAGIT® E PO polyelectrolyte complexes were subsequently processed to double-layer tablets with varying complex loadings on a rotary-die press. Physicochemical interactions were studied under ICH guideline conditions and using the Gordon-Taylor equation. Sorption and desorption were determined to investigate the influence of moisture and temperature on the complex and related to stability tests under accelerated conditions. Naproxen release from the drug-polyelectrolyte complex is triggered by electrolyte concentration. Depending on the complex loading, phosphate buffer pH 6.8 stimulated a biphasic dissolution profile of the produced double-layer tablets: immediate release from the first layer with 65% loading and prolonged release from the second layer within 24 h (98.5% loading). XRPD patterns proved pseudopolymorphism for tablets containing the pure drug under common storage conditions whereas the drug-complex was stable in the amorphous state. Drug-polyelectrolyte complexes enable tailor-made dissolution profiles of solid dosage forms by electrolyte stimulation and increase stability under common storage conditions.

Basic regulatory principles of Escherichia coli's electron transport chain for varying oxygen conditions.

PubMed

Henkel, Sebastian G; Ter Beek, Alexander; Steinsiek, Sonja; Stagge, Stefan; Bettenbrock, Katja; de Mattos, M Joost Teixeira; Sauter, Thomas; Sawodny, Oliver; Ederer, Michael

2014-01-01

For adaptation between anaerobic, micro-aerobic and aerobic conditions Escherichia coli's metabolism and in particular its electron transport chain (ETC) is highly regulated. Although it is known that the global transcriptional regulators FNR and ArcA are involved in oxygen response it is unclear how they interplay in the regulation of ETC enzymes under micro-aerobic chemostat conditions. Also, there are diverse results which and how quinones (oxidised/reduced, ubiquinone/other quinones) are controlling the ArcBA two-component system. In the following a mathematical model of the E. coli ETC linked to basic modules for substrate uptake, fermentation product excretion and biomass formation is introduced. The kinetic modelling focusses on regulatory principles of the ETC for varying oxygen conditions in glucose-limited continuous cultures. The model is based on the balance of electron donation (glucose) and acceptance (oxygen or other acceptors). Also, it is able to account for different chemostat conditions due to changed substrate concentrations and dilution rates. The parameter identification process is divided into an estimation and a validation step based on previously published and new experimental data. The model shows that experimentally observed, qualitatively different behaviour of the ubiquinone redox state and the ArcA activity profile in the micro-aerobic range for different experimental conditions can emerge from a single network structure. The network structure features a strong feed-forward effect from the FNR regulatory system to the ArcBA regulatory system via a common control of the dehydrogenases of the ETC. The model supports the hypothesis that ubiquinone but not ubiquinol plays a key role in determining the activity of ArcBA in a glucose-limited chemostat at micro-aerobic conditions.

Geostatistics: a new tool for describing spatially-varied surface conditions from timber harvested and burned hillslopes

Treesearch

Peter R. Robichaud

1997-01-01

Geostatistics provides a method to describe the spatial continuity of many natural phenomena. Spatial models are based upon the concept of scaling, kriging and conditional simulation. These techniques were used to describe the spatially-varied surface conditions on timber harvest and burned hillslopes. Geostatistical techniques provided estimates of the ground cover (...

Ignition of a Droplet of Composite Liquid Fuel in a Vortex Combustion Chamber

NASA Astrophysics Data System (ADS)

Valiullin, T. R.; Vershinina, K. Yu; Glushkov, D. O.; Strizhak, P. A.

2017-11-01

Experimental study results of a droplet ignition and combustion were obtained for coal-water slurry containing petrochemicals (CWSP) prepared from coal processing waste, low-grade coal and waste petroleum products. A comparative analysis of process characteristics were carried out in different conditions of fuel droplet interaction with heated air flow: droplet soars in air flow in a vortex combustion chamber, droplet soars in ascending air flow in a cone-shaped combustion chamber, and droplet is placed in a thermocouple junction and motionless in air flow. The size (initial radii) of CWSP droplet was varied in the range of 0.5-1.5 mm. The ignition delay time of fuel was determined by the intensity of the visible glow in the vicinity of the droplet during CWSP combustion. It was established (under similar conditions) that ignition delay time of CWSP droplets in the combustion chamber is lower in 2-3.5 times than similar characteristic in conditions of motionless droplet placed in a thermocouple junction. The average value of ignition delay time of CWSP droplet is 3-12 s in conditions of oxidizer temperature is 600-850 K. Obtained experimental results were explained by the influence of heat and mass transfer processes in the droplet vicinity on ignition characteristics in different conditions of CWSP droplet interaction with heated air flow. Experimental results are of interest for the development of combustion technology of promising fuel for thermal power engineering.

Visually cued motor synchronization: modulation of fMRI activation patterns by baseline condition.

PubMed

Cerasa, Antonio; Hagberg, Gisela E; Bianciardi, Marta; Sabatini, Umberto

2005-01-03

A well-known issue in functional neuroimaging studies, regarding motor synchronization, is to design suitable control tasks able to discriminate between the brain structures involved in primary time-keeper functions and those related to other processes such as attentional effort. The aim of this work was to investigate how the predictability of stimulus onsets in the baseline condition modulates the activity in brain structures related to processes involved in time-keeper functions during the performance of a visually cued motor synchronization task (VM). The rational behind this choice derives from the notion that using different stimulus predictability can vary the subject's attention and the consequently neural activity. For this purpose, baseline levels of BOLD activity were obtained from 12 subjects during a conventional-baseline condition: maintained fixation of the visual rhythmic stimuli presented in the VM task, and a random-baseline condition: maintained fixation of visual stimuli occurring randomly. fMRI analysis demonstrated that while brain areas with a documented role in basic time processing are detected independent of the baseline condition (right cerebellum, bilateral putamen, left thalamus, left superior temporal gyrus, left sensorimotor cortex, left dorsal premotor cortex and supplementary motor area), the ventral premotor cortex, caudate nucleus, insula and inferior frontal gyrus exhibited a baseline-dependent activation. We conclude that maintained fixation of unpredictable visual stimuli can be employed in order to reduce or eliminate neural activity related to attentional components present in the synchronization task.

Spatial Analysis of Gravity Data in the California, Nevada, and Utah (US)

NASA Astrophysics Data System (ADS)

Ferani, NA; Hartantyo, E.; Niasari, SW

2018-04-01

The geological condition of western North America is very complex because of the encounter of three major plates namely North America, Juan de Fuca, and Pacific Plate. The process of Juan de Fuca subduction and Pacific transform against North America plate created many mountains and produced Great Basin that we can see extending across California, Nevada, and Utah. The varied natural condition causes the varied value of gravity anomaly distribution. Using Topex free-air anomaly analyzed with second vertical derivative (SVD), we can analyze the fracture structures that occur in the Great Basin. The results show that the maximal SVD anomaly value is higher than the minimal SVD anomaly value at the western and eastern border of Great Basin. This explains that the two of Great Basin border are normal faults with trend direction NW-SE in the western boundary and NE-SW trending in the eastern boundary. This research result corresponds with the high seismicity data along the fault. Through this research, we can know that topex free-air anomaly data can be used to determine the type and trend of fault on a regional scale.

Domain-general contributions to social reasoning: theory of mind and deontic reasoning re-explored.

PubMed

McKinnon, Margaret C; Moscovitch, Morris

2007-02-01

Using older adults and dual-task interference, we examined performance on two social reasoning tasks: theory of mind (ToM) tasks and versions of the deontic selection task involving social contracts and hazardous conditions. In line with performance accounts of social reasoning, evidence from both aging and the dual-task method suggested that domain-general resources contribute to performance of these tasks. Specifically, older adults were impaired relative to younger adults on all types of social reasoning tasks tested; performance varied as a function of the demands these tasks placed on domain-general resources. Moreover, in younger adults, simultaneous performance of a working memory task interfered with younger adults' performance on both types of social reasoning tasks; here too, the magnitude of the interference effect varied with the processing demands of each task. Limits placed on social reasoning by executive functions contribute a great deal to performance, even in old age and in healthy younger adults under conditions of divided attention. The role of potentially non-modular and modular contributions to social reasoning is discussed.

Numerical mixing calculations of confined reacting jet flows in a cylindrical duct

NASA Technical Reports Server (NTRS)

Oechsle, Victor L.; Holdeman, J. D.

1995-01-01

The results reported in this paper describe some of the main flow characteristics and NOx production results which develop in the mixing process in a constant cross-sectional cylindrical duct. A 3-dimensional numerical model has been used to predict the mixing flow field and NOx characteristics in a mixing section of an RQL combustor. Eighteen configurations have been analyzed in a circular geometry in a fully reacting environment simulating the operating condition of an actual RQL gas turbine combustion liner. The evaluation matrix was constructed by varying three parameter: (1) jet-to-mainstream momentum-flux ration (J), (2) orifice shape or orifice aspect ratio, and (3) slot slant angle. The results indicate that the mixing flow field and NOx production significantly vary with the value of the jet penetration and subsequently, slanting elongated slots generally improve the NOx production at high J conditions. Round orifices produce low NOx at low J due to the strong jet penetration. The NOx production trends do not correlate with the mixing non-uniformity parameters described herein.

Response of mixed-phase boundary layer clouds with rapid and slow ice nucleation processes to cloud-top temperature trend

NASA Astrophysics Data System (ADS)

Fridlind, A. M.; Avramov, A.; Ackerman, A. S.; Alpert, P. A.; Knopf, D. A.; DeMott, P. J.; Brooks, S. D.; Glen, A.

2015-12-01

It has been argued on the basis of some laboratory data sets, observed mixed-phase cloud systems, and numerical modeling studies that weakly active or slowly consumed ice forming nuclei (IFN) may be important to natural cloud systems. It has also been argued on the basis of field measurements that ice nucleation under mixed-phase conditions appears to occur predominantly via a liquid-phase mechanism, requiring the presence of liquid droplets prior to substantial ice nucleation. Here we analyze the response of quasi-Lagrangian large-eddy simulations of mixed-phase cloud layers to IFN operating via a liquid-phase mode using assumptions that result in either slow or rapid depletion of IFN from the cloudy boundary layer. Using several generalized case studies that do not exhibit riming or drizzle, based loosely on field campaign data, we vary environmental conditions such that the cloud-top temperature trend varies. One objective of this work is to identify differing patterns in ice formation intensity that may be distinguishable from ground-based or satellite platforms.

Display of high dynamic range images under varying viewing conditions

NASA Astrophysics Data System (ADS)

Borer, Tim

2017-09-01

Recent demonstrations of high dynamic range (HDR) television have shown that superb images are possible. With the emergence of an HDR television production standard (ITU-R Recommendation BT.2100) last year, HDR television production is poised to take off. However research to date has focused principally on HDR image display only under "dark" viewing conditions. HDR television will need to be displayed at varying brightness and under varying illumination (for example to view sport in daytime or on mobile devices). We know, from common practice with conventional TV, that the rendering intent (gamma) should change under brighter conditions, although this is poorly quantified. For HDR the need to render images under varying conditions is all the more acute. This paper seeks to explore the issues surrounding image display under varying conditions. It also describes how visual adaptation is affected by display brightness, surround illumination, screen size and viewing distance. Existing experimental results are presented and extended to try to quantify these effects. Using the experimental results it is described how HDR images may be displayed so that they are perceptually equivalent under different viewing conditions. A new interpretation of the experimental results is reported, yielding a new, luminance invariant model for the appropriate display "gamma". In this way the consistency of HDR image reproduction should be improved, thereby better maintaining "creative intent" in television.

Longitudinal Average Attributable Fraction as a Method for Studying Time-Varying Conditions and Treatments on Recurrent Self-rated Health: The Case of Medications in Older Adults with Multiple Chronic Conditions

PubMed Central

Allore, Heather G.; Zhan, Yilei; Tinetti, Mary; Trentalange, Mark; McAvay, Gail

2015-01-01

Purpose The objective is to modify the longitudinal extension of the average attributable fraction (LE-AAF) for recurrent outcomes with time-varying exposures and control for covariates. Methods We included Medicare Current Beneficiary Survey participants with two or more chronic conditions enrolled from 2005-2009 with follow-up through 2011. Nine time-varying medications indicated for nine time-varying common chronic conditions and 14 out of 18 forward-selected participant characteristics were used as control variables in the generalized estimating equations step of the LE-AAF to estimate associations with the recurrent universal health outcome self-rated health (SRH). Modifications of the LE-AAF were made to accommodate these indicated medication-condition interactions and covariates. Variability was empirically estimated by bias-corrected and accelerated bootstrapping. Results In the adjusted LE-AAF, thiazide, warfarin and clopidogrel had significant contributions of 1.2%, 0.4%, 0.2% respectively to low (poor or fair) SRH; while there were no significant contributions of the other medications to SRH. Hyperlipidemia significantly contributed 4.6% to high SRH. All the other conditions except atrial fibrillation contributed significantly to low SRH. Conclusions Our modifications to the LE-AAF method apply to a recurrent binary outcome with time-varying factors accounting for covariates. PMID:26033374

Modeling soil respiration and variations of source components using a multi-factor global climate change experiment

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

Chen, Xiongwen; Post, Wilfred M; Norby, Richard J

2011-01-01

Soil respiration is an important component of the global carbon cycle and is highly responsive to changes in soil temperature and moisture. Accurate prediction of soil respiration and its changes under future climatic conditions requires a clear understanding of the processes involved. In spite of this, most current empirical soil respiration models incorporate just few of the underlying mechanisms that may influence its response. In this study, a new partial process-based component model built on source components of soil respiration was tested using data collected from a multi-factor climate change experiment that manipulates CO2 concentrations, temperature and precipitation. These resultsmore » were then compared to results generated using several other established models. The component model we tested performed well across different treatments of global climate change. In contrast, some other models, which worked well predicting ambient environmental conditions, were unable to predict the changes under different climate change treatments. Based on the component model, the relative proportions of heterotrophic respiration (Rh) in the total soil respiration at different treatments varied from 0.33 to 0.85. There is a significant increase in the proportion of Rh under the elevated atmospheric CO2 concentration in comparison ambient conditions. The dry treatment resulted in higher proportion of Rh at elevated CO2 and ambient T than under elevated CO2 and elevated T. Also, the ratios between root growth and root maintenance respiration varied across different treatments. Neither increased temperature nor elevated atmospheric CO2 changed Q10 values significantly, while the average Q10 value at wet sites was significantly higher than it at dry sites. There was a higher possibility of increased soil respiration under drying relative to wetting conditions across all treatments based on monthly data, indicating that soil respiration may also be related to soil moisture at previous time periods. Our results reveal that the extent, time delay and contribution of different source components need to be included into mechanistic/processes-based soil respiration models at corresponding scale.« less

Electrophysiological evidence that top-down knowledge controls working memory processing for subsequent visual search.

PubMed

Kawashima, Tomoya; Matsumoto, Eriko

2016-03-23

Items in working memory guide visual attention toward a memory-matching object. Recent studies have shown that when searching for an object this attentional guidance can be modulated by knowing the probability that the target will match an item in working memory. Here, we recorded the P3 and contralateral delay activity to investigate how top-down knowledge controls the processing of working memory items. Participants performed memory task (recognition only) and memory-or-search task (recognition or visual search) in which they were asked to maintain two colored oriented bars in working memory. For visual search, we manipulated the probability that target had the same color as memorized items (0, 50, or 100%). Participants knew the probabilities before the task. Target detection in 100% match condition was faster than that in 50% match condition, indicating that participants used their knowledge of the probabilities. We found that the P3 amplitude in 100% condition was larger than in other conditions and that contralateral delay activity amplitude did not vary across conditions. These results suggest that more attention was allocated to the memory items when observers knew in advance that their color would likely match a target. This led to better search performance despite using qualitatively equal working memory representations.

Electrolytic decontamination of conductive materials for hazardous waste management

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

Wedman, D.E.; Martinez, H.E.; Nelson, T.O.

1996-12-31

Electrolytic removal of plutonium and americium from stainless steel and uranium surfaces has been demonstrated. Preliminary experiments were performed on the electrochemically based decontamination of type 304L stainless steel in sodium nitrate solutions to better understand the metal removal effects of varying cur-rent density, pH, and nitrate concentration parameters. Material removal rates and changes in surface morphology under these varying conditions are reported. Experimental results indicate that an electropolishing step before contamination removes surface roughness, thereby simplifying later electrolytic decontamination. Sodium nitrate based electrolytic decontamination produced the most uniform stripping of material at low to intermediate pH and at sodiummore » nitrate concentrations of 200 g L{sup -1} and higher. Stirring was also observed to increase the uniformity of the stripping process.« less

Early diagnostic of concurrent gear degradation processes progressing under time-varying loads

NASA Astrophysics Data System (ADS)

Guilbault, Raynald; Lalonde, Sébastien

2016-08-01

This study develops a gear diagnostic procedure for the detection of multi- and concurrent degradation processes evolving under time-varying loads. Instead of a conventional comparison between a descriptor and an alarm level, this procedure bases its detection strategy on a descriptor evolution tracking; a lasting descriptor increase denotes the presence of ongoing degradation mechanisms. The procedure works from time domain residual signals prepared in the frequency domain, and accepts any gear conditions as reference signature. To extract the load fluctuation repercussions, the procedure integrates a scaling factor. The investigation first examines a simplification assuming a linear connection between the load and the dynamic response amplitudes. However, while generally valuable, the precision losses associated with large load variations may mask the contribution of tiny flaws. To better reflect the real non-linear relation, the paper reformulates the scaling factor; a power law with an exponent value of 0.85 produces noticeable improvements of the load effect extraction. To reduce the consequences of remaining oscillations, the procedure also includes a filtering phase. During the validation program, a synthetic wear progression assuming a commensurate relation between the wear depth and friction assured controlled evolutions of the surface degradation influence, whereas the fillet crack growth remained entirely determined by the operation conditions. Globally, the tested conditions attest that the final strategy provides accurate monitoring of coexisting isolated damages and general surface deterioration, and that its tracking-detection capacities are unaffected by severe time variations of external loads. The procedure promptly detects the presence of evolving abnormal phenomena. The tests show that the descriptor curve shapes virtually describe the constant wear progression superimposed on the crack length evolution. At the tooth fracture, the mean values of the residual signal evince strong perturbations, while after this episode, the monitoring curves continue signaling the ongoing wear process.

Mineralogy and Microstructures of Shock-Induced Melt Veins in Chondrites

NASA Technical Reports Server (NTRS)

Sharp, Thomas G.

2000-01-01

The applicability of phase equilibrium data to the interpretation of shock-induced melt veins can only be tested by a detailed study of melt- vein mineralogy to see how high-pressure assemblages vary as a function of shock conditions inferred from other indicators. We have used transmission electron microscopy (TEM), analytical electron microscopy (AEM), scanning electron microscopy (SEM), electron microprobe analysis (EMA) and optical petrography to characterize the mineralogy, microstructures, and compositions of melt veins and associated high-pressure minerals in shocked chondrites and SNC meteorites. In the processes, we have gained a better understanding of what melt veining can tell us about shock conditions and we have discovered new mineral phases in chondritic and SNC meteorites.

An Analysis of the Effects of Chip-groove Geometry on Machining Performance Using Finite Element Methods

NASA Astrophysics Data System (ADS)

Ee, K. C.; Dillon, O. W.; Jawahir, I. S.

2004-06-01

This paper discusses the influence of major chip-groove parameters of a cutting tool on the chip formation process in orthogonal machining using finite element (FE) methods. In the FE formulation, a thermal elastic-viscoplastic material model is used together with a modified Johnson-Cook material law for the flow stress. The chip back-flow angle and the chip up-curl radius are calculated for a range of cutting conditions by varying the chip-groove parameters. The analysis provides greater understanding of the effectiveness of chip-groove configurations and points a way to correlate cutting conditions with tool-wear when machining with a grooved cutting tool.

Single-Molecule Studies of Hyaluronic Acid Conformation

NASA Astrophysics Data System (ADS)

Innes-Gold, Sarah; Berezney, John; Saleh, Omar

Hyaluronic acid (HA) is a charged linear polysaccharide abundant in extracellular spaces. Its solution conformation and mechanical properties help define the environment outside of cells, play key roles in cell motility and adhesion processes, and are of interest for the development of HA biomaterials. Intra-chain hydrogen bonds and electrostatic repulsion contribute to HAs physical structure, but the nature of this structure, as well as its dependence on solution electrostatics, are not well-understood. To address this problem, we have investigated HA conformation and mechanical properties under a range of solution conditions systematically designed to affect charge screening or hydrogen bonding. We used magnetic tweezers to apply biological-scale stretching forces to individual HA chains under varying solution conditions.

XPS Investigation on Changes in UO 2 Speciation following Exposure to Humidity

DOE PAGES

Donald, Scott B.; Davisson, M. Lee; Nelson, Art J.

2016-04-27

High purity UO 2powder samples were subjected to accelerated aging under controlled conditions with relative humidity ranging from 34% to 98%. Characterization of the chemical speciation of the products was accomplished using X-ray photoelectron spectroscopy (XPS). A shift to higher uranium oxidation states was found to be directly correlated to increased relative humidity exposure. In addition, the relative abundance of O 2-, OH -, and H 2O was found to vary with exposure time. Therefore, it is expected that uranium oxide materials exposed to high relative humidity conditions during processing and storage would display a similar increase in average uraniummore » valence.« less

Understanding dynamic pattern and process across spatial scales in river systems using simultaneous deployments of in situ sensors

NASA Astrophysics Data System (ADS)

Wollheim, W. M.; Mulukutla, G.; Cook, C.; Carey, R. O.

2014-12-01

Biogeochemical conditions throughout aquatic landscapes are spatially varied and temporally dynamic due to interactions of upstream land use, climate, hydrologic responses, and internal aquatic processes. One of the key goals in aquatic ecosystem ecology is to parse the upstream influences of terrestrial and aquatic processes on local conditions, which becomes progressively more difficult as watershed size increases and as processes are altered by diverse human activities. Simultaneous deployments of high frequency, in situ aquatic sensors for multiple constituents (e.g. NO3-N, CDOM, turbidity, conductivity, D.O., water temperature, along with flow) offer a new approach for understanding patterns along the aquatic continuum. For this talk, we explore strategies for deployments within single watersheds to improve understanding of terrestrial and aquatic processes. We address applications regarding mobilization of non-point nutrient sources across temporal scales, interactions with land use and watershed size, and the importance of aquatic processes. We also explore ways in which simultaneous sensor deployments can be designed to improve parameterization and testing of river network biogeochemical models. We will provide several specific examples using conductivity, nitrate and carbon from ongoing sensor deployments in New England, USA. We expect that improved deployments of sensors and sensor networks will benefit the management of critical freshwater resources.

Fault Detection and Diagnosis In Hall-Héroult Cells Based on Individual Anode Current Measurements Using Dynamic Kernel PCA

NASA Astrophysics Data System (ADS)

Yao, Yuchen; Bao, Jie; Skyllas-Kazacos, Maria; Welch, Barry J.; Akhmetov, Sergey

2018-04-01

Individual anode current signals in aluminum reduction cells provide localized cell conditions in the vicinity of each anode, which contain more information than the conventionally measured cell voltage and line current. One common use of this measurement is to identify process faults that can cause significant changes in the anode current signals. While this method is simple and direct, it ignores the interactions between anode currents and other important process variables. This paper presents an approach that applies multivariate statistical analysis techniques to individual anode currents and other process operating data, for the detection and diagnosis of local process abnormalities in aluminum reduction cells. Specifically, since the Hall-Héroult process is time-varying with its process variables dynamically and nonlinearly correlated, dynamic kernel principal component analysis with moving windows is used. The cell is discretized into a number of subsystems, with each subsystem representing one anode and cell conditions in its vicinity. The fault associated with each subsystem is identified based on multivariate statistical control charts. The results show that the proposed approach is able to not only effectively pinpoint the problematic areas in the cell, but also assess the effect of the fault on different parts of the cell.

ROSE: the road simulation environment

NASA Astrophysics Data System (ADS)

Liatsis, Panos; Mitronikas, Panogiotis

1997-05-01

Evaluation of advanced sensing systems for autonomous vehicle navigation (AVN) is currently carried out off-line with prerecorded image sequences taken by physically attaching the sensors to the ego-vehicle. The data collection process is cumbersome and costly as well as highly restricted to specific road environments and weather conditions. This work proposes the use of scientific animation in modeling and representation of real-world traffic scenes and aims to produce an efficient, reliable and cost-effective concept evaluation suite for AVN sensing algorithms. ROSE is organized in a modular fashion consisting of the route generator, the journey generator, the sequence description generator and the renderer. The application was developed in MATLAB and POV-Ray was selected as the rendering module. User-friendly graphical user interfaces have been designed to allow easy selection of animation parameters and monitoring of the generation proces. The system, in its current form, allows the generation of various traffic scenarios, providing for an adequate number of static/dynamic objects, road types and environmental conditions. Initial tests on the robustness of various image processing algorithms to varying lighting and weather conditions have been already carried out.

Syngas production by high temperature steam/CO2 coelectrolysis using solid oxide electrolysis cells.

PubMed

Chen, Xinbing; Guan, Chengzhi; Xiao, Guoping; Du, Xianlong; Wang, Jian-Qiang

2015-01-01

High temperature (HT) steam/CO2 coelectrolysis with solid oxide electrolysis cells (SOECs) using the electricity and heat generated from clean energies is an important alternative for syngas production without fossil fuel consumption and greenhouse gas emissions. Herein, reaction characteristics and the outlet syngas composition of HT steam/CO2 coelectrolysis under different operating conditions, including distinct inlet gas compositions and electrolysis current densities, are systematically studied at 800 °C using commercially available SOECs. The HT coelectrolysis process, which has comparable performance to HT steam electrolysis, is more active than the HT CO2 electrolysis process, indicating the important contribution of the reverse water-gas shift reaction in the formation of CO. The outlet syngas composition from HT steam/CO2 coelectrolysis is very sensitive to the operating conditions, indicating the feasibility of controlling the syngas composition by varying these conditions. Maximum steam and CO2 utilizations of 77% and 76% are achieved at 1.0 A cm(-2) with an inlet gas composition of 20% H2/40% steam/40% CO2.

Some effects of alcohol and eye movements on cross-race face learning.

PubMed

Harvey, Alistair J

2014-01-01

This study examines the impact of acute alcohol intoxication on visual scanning in cross-race face learning. The eye movements of a group of white British participants were recorded as they encoded a series of own-and different-race faces, under alcohol and placebo conditions. Intoxication reduced the rate and extent of visual scanning during face encoding, reorienting the focus of foveal attention away from the eyes and towards the nose. Differences in encoding eye movements also varied between own-and different-race face conditions as a function of alcohol. Fixations to both face types were less frequent and more lingering following intoxication, but in the placebo condition this was only the case for different-race faces. While reducing visual scanning, however, alcohol had no adverse effect on memory, only encoding restrictions associated with sober different-race face processing led to poorer recognition. These results support perceptual expertise accounts of own-race face processing, but suggest the adverse effects of alcohol on face learning published previously are not caused by foveal encoding restrictions. The implications of these findings for alcohol myopia theory are discussed.

Dark chocolate acceptability: influence of cocoa origin and processing conditions.

PubMed

Torres-Moreno, Miriam; Tarrega, Amparo; Costell, Elvira; Blanch, Consol

2012-01-30

Chocolate properties can vary depending on cocoa origin, composition and manufacturing procedure, which affect consumer acceptability. The aim of this work was to study the effect of two cocoa origins (Ghana and Ecuador) and two processing conditions (roasting time and conching time) on dark chocolate acceptability. Overall acceptability and acceptability for different attributes (colour, flavour, odour and texture) were evaluated by 95 consumers. Differences in acceptability among dark chocolates were mainly related to differences in flavour acceptability. The use of a long roasting time lowered chocolate acceptability in Ghanaian samples while it had no effect on acceptability of Ecuadorian chocolates. This response was observed for most consumers (two subgroups with different frequency consumption of dark chocolate). However, for a third group of consumers identified as distinguishers, the most acceptable dark chocolate samples were those produced with specific combinations of roasting time and conching time for each of the cocoa geographical origin considered. To produce dark chocolates from a single origin it is important to know the target market preferences and to select the appropriate roasting and conching conditions. Copyright © 2011 Society of Chemical Industry.

Nonlinear dynamics under varying temperature conditions of the resonating beams of a differential resonant accelerometer

NASA Astrophysics Data System (ADS)

Zhang, Jing; Wang, Yagang; Zega, Valentina; Su, Yan; Corigliano, Alberto

2018-07-01

In this work the nonlinear dynamic behaviour under varying temperature conditions of the resonating beams of a differential resonant accelerometer is studied from the theoretical, numerical and experimental points of view. A complete analytical model based on the Hamilton’s principle is proposed to describe the nonlinear behaviour of the resonators under varying temperature conditions and numerical solutions are presented in comparison with experimental data. This provides a novel perspective to examine the relationship between temperature and nonlinearity, which helps predicting the dynamic behaviour of resonant devices and can guide their optimal design.

Transient Point Infiltration In The Unsaturated Zone

NASA Astrophysics Data System (ADS)

Buecker-Gittel, M.; Mohrlok, U.

The risk assessment of leaking sewer pipes gets more and more important due to urban groundwater management and environmental as well as health safety. This requires the quantification and balancing of transport and transformation processes based on the water flow in the unsaturated zone. The water flow from a single sewer leakage could be described as a point infiltration with time varying hydraulic conditions externally and internally. External variations are caused by the discharge in the sewer pipe as well as the state of the leakage itself. Internal variations are the results of microbiological clogging effects associated with the transformation processes. Technical as well as small scale laboratory experiments were conducted in order to investigate the water transport from an transient point infiltration. From the technical scale experiment there was evidence that the water flow takes place under transient conditions when sewage infiltrates into an unsaturated soil. Whereas the small scale experiments investigated the hydraulics of the water transport and the associated so- lute and particle transport in unsaturated soils in detail. The small scale experiment was a two-dimensional representation of such a point infiltration source where the distributed water transport could be measured by several tensiometers in the soil as well as by a selective measurement of the discharge at the bottom of the experimental setup. Several series of experiments were conducted varying the boundary and initial con- ditions in order to derive the important parameters controlling the infiltration of pure water from the point source. The results showed that there is a significant difference between the infiltration rate in the point source and the discharge rate at the bottom, that could be explained by storage processes due to an outflow resistance at the bottom. This effect is overlayn by a decreasing water content decreases over time correlated with a decreasing infiltration rate. As expected the initial conditions mainly affects the time scale for the water transport. Additionally, the influence of preferential flow paths on the discharge distribution could be found due to the heterogenieties caused by the filling and compaction process of the sandy soil.

A 2-D process-based model for suspended sediment dynamics: A first step towards ecological modeling

USGS Publications Warehouse

Achete, F. M.; van der Wegen, M.; Roelvink, D.; Jaffe, B.

2015-01-01

In estuaries suspended sediment concentration (SSC) is one of the most important contributors to turbidity, which influences habitat conditions and ecological functions of the system. Sediment dynamics differs depending on sediment supply and hydrodynamic forcing conditions that vary over space and over time. A robust sediment transport model is a first step in developing a chain of models enabling simulations of contaminants, phytoplankton and habitat conditions. This works aims to determine turbidity levels in the complex-geometry delta of the San Francisco estuary using a process-based approach (Delft3D Flexible Mesh software). Our approach includes a detailed calibration against measured SSC levels, a sensitivity analysis on model parameters and the determination of a yearly sediment budget as well as an assessment of model results in terms of turbidity levels for a single year, water year (WY) 2011. Model results show that our process-based approach is a valuable tool in assessing sediment dynamics and their related ecological parameters over a range of spatial and temporal scales. The model may act as the base model for a chain of ecological models assessing the impact of climate change and management scenarios. Here we present a modeling approach that, with limited data, produces reliable predictions and can be useful for estuaries without a large amount of processes data.

Canola Cake as a Potential Substrate for Proteolytic Enzymes Production by a Selected Strain of Aspergillus oryzae: Selection of Process Conditions and Product Characterization

PubMed Central

Freitas, Adriana C.; Castro, Ruann J. S.; Fontenele, Maria A.; Egito, Antonio S.; Farinas, Cristiane S.; Pinto, Gustavo A. S.

2013-01-01

Oil cakes have excellent nutritional value and offer considerable potential for use in biotechnological processes that employ solid-state fermentation (SSF) for the production of high value products. This work evaluates the feasibility of using canola cake as a substrate for protease production by a selected strain of Aspergillus oryzae cultivated under SSF. The influences of the following process parameters were considered: initial substrate moisture content, incubation temperature, inoculum size, and pH of the buffer used for protease extraction and activity analysis. Maximum protease activity was obtained after cultivating Aspergillus oryzae CCBP 001 at 20°C, using an inoculum size of 107 spores/g in canola cake medium moistened with 40 mL of water to 100 g of cake. Cultivation and extraction under selected conditions increased protease activity 5.8-fold, compared to the initial conditions. Zymogram analysis of the enzymatic extract showed that the protease molecular weights varied between 31 and 200 kDa. The concentrated protease extract induced clotting of casein in 5 min. The results demonstrate the potential application of canola cake for protease production under SSF and contribute to the technological advances needed to increase the efficiency of processes designed to add value to agroindustrial wastes. PMID:24455400

Virtual reality Stroop task for assessment of supervisory attentional processing.

PubMed

Parsons, Thomas D; Courtney, Christopher G; Dawson, Michael E

2013-01-01

The current project is a preliminary attempt at assessing the potential of a three-dimensional virtual reality Stroop task (VRST) for investigation of supervisory attentional processing. The VRST was compared with paper-and-pencil and computer automated (two-dimensional) versions of the Stroop. Psychophysiological measures were also used to assess varying levels of user arousal. The three versions of the Stroop task were conducted with a sample of 50 healthy university students, between the ages of 18 and 28 years, which included equivalent distributions of men and women from ethnically diverse populations. No significant differences were found for age, gender, or education. Results indicated that the typical Stroop effect pattern found in the Delis-Kaplan Executive Function System (D-KEFS) and Automated Neuropsychological Assessment Metrics (ANAM) occurs in the VRST; the complexity condition of the VRST offers potential for assessment of exogenous and endogenous attentional processing; the two single-item presentation formats of the Stroop are comparable; there is a psychophysiological difference in arousal between low- and high-threat zones; and while there is a learning effect present in the VRST across conditions, it is limited by the arousal conditions in the high-threat zones. Additionally, no negative side effects were associated with use of the virtual environment. We conclude that the VRST has the potential to offer a novel approach to assessment of supervisory attentional processing within an ecologically relevant environment.

A 2-D process-based model for suspended sediment dynamics: a first step towards ecological modeling

NASA Astrophysics Data System (ADS)

Achete, F. M.; van der Wegen, M.; Roelvink, D.; Jaffe, B.

2015-06-01

In estuaries suspended sediment concentration (SSC) is one of the most important contributors to turbidity, which influences habitat conditions and ecological functions of the system. Sediment dynamics differs depending on sediment supply and hydrodynamic forcing conditions that vary over space and over time. A robust sediment transport model is a first step in developing a chain of models enabling simulations of contaminants, phytoplankton and habitat conditions. This works aims to determine turbidity levels in the complex-geometry delta of the San Francisco estuary using a process-based approach (Delft3D Flexible Mesh software). Our approach includes a detailed calibration against measured SSC levels, a sensitivity analysis on model parameters and the determination of a yearly sediment budget as well as an assessment of model results in terms of turbidity levels for a single year, water year (WY) 2011. Model results show that our process-based approach is a valuable tool in assessing sediment dynamics and their related ecological parameters over a range of spatial and temporal scales. The model may act as the base model for a chain of ecological models assessing the impact of climate change and management scenarios. Here we present a modeling approach that, with limited data, produces reliable predictions and can be useful for estuaries without a large amount of processes data.

Theoretical and experimental study of the formation conditions of stepped leaders in negative flashes

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

Xie, Shijun, E-mail: sj-xie@163.com; State Key Laboratory of Control and Simulation of Power System and Generation Equipment, Department of Electrical Engineering, Tsinghua University, Beijing 100084; Zeng, Rong

2015-08-15

Natural lightning flashes are stochastic and uncontrollable, and thus, it is difficult to observe the formation process of a downward negative stepped leader (NSL) directly and in detail. This situation has led to some dispute over the actual NSL formation mechanism, and thus has hindered improvements in the lightning shielding analysis model. In this paper, on the basis of controllable long air gap discharge experiments, the formation conditions required for NSLs in negative flashes have been studied. First, a series of simulation experiments on varying scales were designed and carried out. The NSL formation processes were observed, and several ofmore » the characteristic process parameters, including the scale, the propagation velocity, and the dark period, were obtained. By comparing the acquired formation processes and the characteristic parameters with those in natural lightning flashes, the similarity between the NSLs in the simulation experiments and those in natural flashes was proved. Then, based on the local thermodynamic equation and the space charge estimation method, the required NSL formation conditions were deduced, and the space background electric field (E{sub b}) was proposed as the primary parameter for NSL formation. Finally, the critical value of E{sub b} required for the formation of NSLs in natural flashes was determined to be approximately 75 kV/m by extrapolation of the results of the simulation experiments.« less

Heart rate variability and cognitive processing: The autonomic response to task demands.

PubMed

Luque-Casado, Antonio; Perales, José C; Cárdenas, David; Sanabria, Daniel

2016-01-01

This study investigated variations in heart rate variability (HRV) as a function of cognitive demands. Participants completed an execution condition including the psychomotor vigilance task, a working memory task and a duration discrimination task. The control condition consisted of oddball versions (participants had to detect the rare event) of the tasks from the execution condition, designed to control for the effect of the task parameters (stimulus duration and stimulus rate) on HRV. The NASA-TLX questionnaire was used as a subjective measure of cognitive workload across tasks and conditions. Three major findings emerged from this study. First, HRV varied as a function of task demands (with the lowest values in the working memory task). Second, and crucially, we found similar HRV values when comparing each of the tasks with its oddball control equivalent, and a significant decrement in HRV as a function of time-on-task. Finally, the NASA-TLX results showed larger cognitive workload in the execution condition than in the oddball control condition, and scores variations as a function of task. Taken together, our results suggest that HRV is highly sensitive to overall demands of sustained attention over and above the influence of other cognitive processes suggested by previous literature. In addition, our study highlights a potential dissociation between objective and subjective measures of mental workload, with important implications in applied settings. Copyright © 2015 Elsevier B.V. All rights reserved.

Freeze-cast alumina pore networks: Effects of freezing conditions and dispersion medium

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

Miller, S. M.; Xiao, X.; Faber, K. T.

Alumina ceramics were freeze-cast from water- and camphene-based slurries under varying freezing conditions and examined using X-ray computed tomography (XCT). Pore network characteristics, i.e., porosity, pore size, geometric surface area, and tortuosity, were measured from XCT reconstructions and the data were used to develop a model to predict feature size from processing conditions. Classical solidification theory was used to examine relationships between pore size, temperature gradients, and freezing front velocity. Freezing front velocity was subsequently predicted from casting conditions via the two-phase Stefan problem. Resulting models for water-based samples agreed with solidification-based theories predicting lamellar spacing of binary eutectic alloys,more » and models for camphene-based samples concurred with those for dendritic growth. Relationships between freezing conditions and geometric surface area were also modeled by considering the inverse relationship between pore size and surface area. Tortuosity was determined to be dependent primarily on the type of dispersion medium. (C) 2015 Elsevier Ltd. All rights reserved.« less

Simulation of dynamic processes when machining transition surfaces of stepped shafts

NASA Astrophysics Data System (ADS)

Maksarov, V. V.; Krasnyy, V. A.; Viushin, R. V.

2018-03-01

The paper addresses the characteristics of stepped surfaces of parts categorized as "solids of revolution". It is noted that in the conditions of transition modes during the switch to end surface machining, there is cutting with varied load intensity in the section of the cut layer, which leads to change in cutting force, onset of vibrations, an increase in surface layer roughness, a decrease of size precision, and increased wear of a tool's cutting edge. This work proposes a method that consists in developing a CNC program output code that allows one to process complex forms of stepped shafts with only one machine setup. The authors developed and justified a mathematical model of a technological system for mechanical processing with consideration for the resolution of tool movement at the stages of transition processes to assess the dynamical stability of a system in the process of manufacturing stepped surfaces of parts of “solid of revolution” type.

One process is not enough! A speed-accuracy tradeoff study of recognition memory.

PubMed

Boldini, Angela; Russo, Riccardo; Avons, S E

2004-04-01

Speed-accuracy tradeoff (SAT) methods have been used to contrast single- and dual-process accounts of recognition memory. In these procedures, subjects are presented with individual test items and are required to make recognition decisions under various time constraints. In this experiment, we presented word lists under incidental learning conditions, varying the modality of presentation and level of processing. At test, we manipulated the interval between each visually presented test item and a response signal, thus controlling the amount of time available to retrieve target information. Study-test modality match had a beneficial effect on recognition accuracy at short response-signal delays (< or =300 msec). Conversely, recognition accuracy benefited more from deep than from shallow processing at study only at relatively long response-signal delays (> or =300 msec). The results are congruent with views suggesting that both fast familiarity and slower recollection processes contribute to recognition memory.

Manufacturing polymer light emitting diode with high luminance efficiency by solution process

NASA Astrophysics Data System (ADS)

Kim, Miyoung; Jo, SongJin; Yang, Ho Chang; Yoon, Dang Mo; Kwon, Jae-Taek; Lee, Seung-Hyun; Choi, Ju Hwan; Lee, Bum-Joo; Shin, Jin-Koog

2012-06-01

While investigating polymer light emitting diodes (polymer-LEDs) fabricated by solution process, surface roughness influences electro-optical (E-O) characteristics. We expect that E-O characteristics such as luminance and power efficiency related to surface roughness and layer thickness of emitting layer with poly-9-Vinylcarbazole. In this study, we fabricated polymer organic light emitting diodes by solution process which guarantees easy, eco-friendly and low cost manufacturing for flexible display applications. In order to obtain high luminescence efficiency, E-O characteristics of these devices by varying parameters for printing process have been investigated. Therefore, we optimized process condition for polymer-LEDs by adjusting annealing temperatures of emission, thickness of emission layer showing efficiency (10.8 cd/A) at 10 mA/cm2. We also checked wavelength dependent electroluminescence spectrum in order to find the correlation between the variation of efficiency and the thickness of the layer.

On Cellular Darwinism: Mitochondria.

PubMed

Bull, Larry

2016-01-01

The significant role of mitochondria within cells is becoming increasingly clear. This letter uses the NKCS model of coupled fitness landscapes to explore aspects of organelle-nucleus coevolution. The phenomenon of mitochondrial diversity is allowed to emerge under a simple intracellular evolutionary process, including varying the relative rate of evolution by the organelle. It is shown how the conditions for the maintenance of more than one genetic variant of mitochondria are similar to those previously suggested as needed for the original symbiotic origins of the relationship using the NKCS model.

Cold worked ferritic alloys and components

DOEpatents

Korenko, Michael K.

1984-01-01

This invention relates to liquid metal fast breeder reactor and steam generator precipitation hardening fully ferritic alloy components which have a microstructure substantially free of the primary precipitation hardening phase while having cells or arrays of dislocations of varying population densities. It also relates to the process by which these components are produced, which entails solution treating the alloy followed by a final cold working step. In this condition, the first significant precipitation hardening of the component occurs during high temperature use.

Enhancement and inhibition of second-harmonic generation and absorption in a negative index cavity.

PubMed

de Ceglia, Domenico; D'Orazio, Antonella; De Sario, Marco; Petruzzelli, Vincenzo; Prudenzano, Francesco; Centini, Marco; Cappeddu, Mirko G; Bloemer, Mark J; Scalora, Michael

2007-02-01

We study second-harmonic generation in a negative-index material cavity. The transmission spectrum shows a bandgap between the electric and magnetic plasma frequencies. The nonlinear process is made efficient by local phase-matching conditions between a forward-propagating pump and a backward-propagating second-harmonic signal. By simultaneously exciting the cavity with counterpropagating pulses, and by varying their relative phase difference, one is able to enhance or inhibit linear absorption and the second-harmonic conversion efficiency.

Varied Human Tolerance to the Combined Conditions of Low Contrast and Diminished Luminance: A Quasi-Meta Analysis

DTIC Science & Technology

2017-08-30

as being three-fold: 1) a measurement of the integrity of both the central and peripheral visual processing centers; 2) an indicator of detail...visual assessment task 12 integral to the Army’s Class 1 Flight Physical (Ginsburg, 1981 and 1984; Bachman & Behar, 1986). During a Class 1 flight...systems. Meta-analysis has been defined as the statistical analysis of a collection of analytical results for the purpose of integrating the findings

Social and attentional aspects of echolalia in highly echolalic mentally retarded persons.

PubMed

Campbell, B; Grieve, R

1978-01-01

Echolalia was examined in a sample of highly echolalic mentally retarded individuals. When presented with a standard set of questions, under conditions differing in appropriateness for exchange of discourse (e.g., questions presented with examiner and patient face-to-face vs. questions presented with the examiner's face averted vs. questions addressed towards another person sitting silently beside the patient), subjects' frequency of echolalia varied. Besides showing considerable sensitivity to aspects of discourse exchange, subjects exhibited some limited capacity for processing linguistic information.

Estimating and mapping ecological processes influencing microbial community assembly

DOE PAGES

Stegen, James C.; Lin, Xueju; Fredrickson, Jim K.; ...

2015-05-01

Ecological community assembly is governed by a combination of (i) selection resulting from among-taxa differences in performance; (ii) dispersal resulting from organismal movement; and (iii) ecological drift resulting from stochastic changes in population sizes. The relative importance and nature of these processes can vary across environments. Selection can be homogeneous or variable, and while dispersal is a rate, we conceptualize extreme dispersal rates as two categories; dispersal limitation results from limited exchange of organisms among communities, and homogenizing dispersal results from high levels of organism exchange. To estimate the influence and spatial variation of each process we extend a recentlymore » developed statistical framework, use a simulation model to evaluate the accuracy of the extended framework, and use the framework to examine subsurface microbial communities over two geologic formations. For each subsurface community we estimate the degree to which it is influenced by homogeneous selection, variable selection, dispersal limitation, and homogenizing dispersal. Our analyses revealed that the relative influences of these ecological processes vary substantially across communities even within a geologic formation. We further identify environmental and spatial features associated with each ecological process, which allowed mapping of spatial variation in ecological-process-influences. The resulting maps provide a new lens through which ecological systems can be understood; in the subsurface system investigated here they revealed that the influence of variable selection was associated with the rate at which redox conditions change with subsurface depth.« less

The Inversion Effect for Chinese Characters is Modulated by Radical Organization.

PubMed

Luo, Canhuang; Chen, Wei; Zhang, Ye

2017-06-01

In studies of visual object recognition, strong inversion effects accompany the acquisition of expertise and imply the involvement of configural processing. Chinese literacy results in sensitivity to the orthography of Chinese characters. While there is some evidence that this orthographic sensitivity results in an inversion effect, and thus involves configural processing, that processing might depend on exact orthographic properties. Chinese character recognition is believed to involve a hierarchical process, involving at least two lower levels of representation: strokes and radicals. Radicals are grouped into characters according to certain types of structure, i.e. left-right structure, top-bottom structure, or simple characters with only one radical by itself. These types of radical structures vary in both familiarity, and in hierarchical level (compound versus simple characters). In this study, we investigate whether the hierarchical-level or familiarity of radical-structure has an impact on the magnitude of the inversion effect. Participants were asked to do a matching task on pairs of either upright or inverted characters with all the types of structure. Inversion effects were measured based on both reaction time and response sensitivity. While an inversion effect was observed in all 3 conditions, the magnitude of the inversion effect varied with radical structure, being significantly larger for the most familiar type of structure: characters consisting of 2 radicals organized from left to right. These findings indicate that character recognition involves extraction of configural structure as well as radical processing which play different roles in the processing of compound characters and simple characters.

Heuristic and analytic processing: age trends and associations with cognitive ability and cognitive styles.

PubMed

Kokis, Judite V; Macpherson, Robyn; Toplak, Maggie E; West, Richard F; Stanovich, Keith E

2002-09-01

Developmental and individual differences in the tendency to favor analytic responses over heuristic responses were examined in children of two different ages (10- and 11-year-olds versus 13-year-olds), and of widely varying cognitive ability. Three tasks were examined that all required analytic processing to override heuristic processing: inductive reasoning, deductive reasoning under conditions of belief bias, and probabilistic reasoning. Significant increases in analytic responding with development were observed on the first two tasks. Cognitive ability was associated with analytic responding on all three tasks. Cognitive style measures such as actively open-minded thinking and need for cognition explained variance in analytic responding on the tasks after variance shared with cognitive ability had been controlled. The implications for dual-process theories of cognition and cognitive development are discussed.

The Role of Economic Strain on Adolescent Delinquency: A Microsocial Process Model

PubMed Central

Low, Sabina; Sinclair, Ryan; Shortt, Joann Wu

2013-01-01

The current study examines the role of economic strain as a moderator of the microsocial processes influencing younger siblings’ delinquency (externalizing behavior and substance use) in a longitudinal design. The younger siblings (122 younger brothers and 122 younger sisters) were from 244 families with same-sex biological siblings. Structural equation modeling was utilized to examine a process model whereby mothers’ harsh/inconsistent parenting and older sibling delinquency influence younger siblings’ delinquent behavior via sibling aggression and delinquent peer affiliation. Findings suggest that indirect mechanisms vary as a function of economic strain, with sibling aggression having a stronger, more detrimental effect on adolescent delinquency in economically strained families. Data suggest that familial economic conditions contextualize the relative roles of parenting, sibling, and peer processes in the transmission of risk to adolescent delinquency. PMID:22709262

Change of pH during excess sludge fermentation under alkaline, acidic and neutral conditions.

PubMed

Yuan, Yue; Peng, Yongzhen; Liu, Ye; Jin, Baodan; Wang, Bo; Wang, Shuying

2014-12-01

The change in pH during excess sludge (ES) fermentation of varying sludge concentrations was investigated in a series of reactors at alkaline, acidic, and neutral pHs. The results showed that the changes were significantly affected by fermentative conditions. Under different conditions, pH exhibited changing profiles. When ES was fermented under alkaline conditions, pH decreased in a range of (10±1). At the beginning of alkaline fermentation, pH dropped significantly, at intervals of 4h, 4h, and 5h with sludge concentrations of 8665.6mg/L, 6498.8mg/L, and 4332.5mg/L, then it would become moderate. However, under acidic conditions, pH increased from 4 to 5. Finally, under neutral conditions pH exhibited a decrease then an increase throughout entire fermentation process. Further study showed short-chain fatty acids (SCFAs), ammonia nitrogen and cations contributed to pH change under various fermentation conditions. This study presents a novel strategy based on pH change to predict whether SCFAs reach their stable stage. Copyright © 2014 Elsevier Ltd. All rights reserved.

The influence of memory and attention on the ear advantage in dichotic listening.

PubMed

D'Anselmo, Anita; Marzoli, Daniele; Brancucci, Alfredo

2016-12-01

The role of memory retention and attentional control on hemispheric asymmetry was investigated using a verbal dichotic listening paradigm, with the consonant-vowel syllables (/ba/,/da/,/ga/,/ka/,/pa/and/ta/), while manipulating the focus of attention and the time interval between stimulus and response. Attention was manipulated using three conditions: non-forced (NF), forced left (FL) and forced right (FR) attention. Memory involvement was varied using four delays (0, 1, 3 and 4 s) between stimulus presentation and response. Results showed a significant right ear advantage (REA) in the NF condition and an increased REA in the FR condition. A left ear advantage (LEA) was found in FL condition. The REA increased significantly in the NF attention condition at the 3-s compared to the 0-s delay and in the FR condition at the 1-s compared to the 0-s delay. No modulation of the left ear advantage was observed in the FL condition. These results are discussed in terms of an interaction between attentional processes and memory retention. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of simulated microgravity on oxidation-sensitive gene expression in PC12 cells

NASA Astrophysics Data System (ADS)

Kwon, Ohwon; Sartor, Maureen; Tomlinson, Craig R.; Millard, Ronald W.; Olah, Mark E.; Sankovic, John M.; Banerjee, Rupak K.

2006-01-01

Oxygen utilization by and oxygen dependence of cellular processes may be different in biological systems that are exposed to microgravity (micro-g). A baseline in which cellular changes in oxygen sensitive molecular processes occur during micro-g conditions would be important to pursue this question. The objective of this research is to analyze oxidation-sensitive gene expression in a model cell line [rat pheochromocytoma (PC12)] under simulated micro-g conditions. The PC12 cell line is well characterized in its response to oxygen, and is widely recognized as a sensitive model for studying the responses of oxygen-sensitive molecular and cellular processes. This study uses the rotating wall vessel bioreactor (RWV) designed at NASA to simulate micro-g. Gene expression in PC12 cells in response to micro-g was analyzed by DNA microarray technology. The microarray analysis of PC12 cells cultured for 4 days under simulated micro-g under standardized oxygen environment conditions revealed more than 100 genes whose expression levels were changed at least twofold (up-regulation of 65 genes and down-regulation of 39 genes) compared with those from cells in the unit gravity (unit-g) control. This study observed that genes involved in the oxidoreductase activity category were most significantly differentially expressed under micro-g conditions. Also, known oxidation-sensitive transcription factors such as hypoxia-inducible factor-2α, c-myc, and the peroxisome proliferator-activated receptor-γ were changed significantly. Our initial results from the gene expression microarray studies may provide a context in which to evaluate the effect of varying oxygen environments on the background of differential gene regulation of biological processes under variable gravity conditions.

Effect of simulated microgravity on oxidation-sensitive gene expression in PC12 cells

PubMed Central

Kwon, Ohwon; Sartor, Maureen; Tomlinson, Craig R.; Millard, Ronald W.; Olah, Mark E.; Sankovic, John M.; Banerjee, Rupak K.

2008-01-01

Oxygen utilization by and oxygen dependence of cellular processes may be different in biological systems that are exposed to microgravity (micro-g). A baseline in which cellular changes in oxygen sensitive molecular processes occur during micro-g conditions would be important to pursue this question. The objective of this research is to analyze oxidation-sensitive gene expression in a model cell line [rat pheochromocytoma (PC12)] under simulated micro-g conditions. The PC12 cell line is well characterized in its response to oxygen, and is widely recognized as a sensitive model for studying the responses of oxygen-sensitive molecular and cellular processes. This study uses the rotating wall vessel bioreactor (RWV) designed at NASA to simulate micro-g. Gene expression in PC12 cells in response to micro-g was analyzed by DNA microarray technology. The microarray analysis of PC12 cells cultured for 4 days under simulated micro-g under standardized oxygen environment conditions revealed more than 100 genes whose expression levels were changed at least twofold (up-regulation of 65 genes and down-regulation of 39 genes) compared with those from cells in the unit gravity (unit-g) control. This study observed that genes involved in the oxidoreductase activity category were most significantly differentially expressed under micro-g conditions. Also, known oxidation-sensitive transcription factors such as hypoxia-inducible factor-2α, c-myc, and the peroxisome proliferator-activated receptor-γ were changed significantly. Our initial results from the gene expression microarray studies may provide a context in which to evaluate the effect of varying oxygen environments on the background of differential gene regulation of biological processes under variable gravity conditions. PMID:19081771

Informational Masking Effects on Neural Encoding of Stimulus Onset and Acoustic Change.

PubMed

Niemczak, Christopher E; Vander Werff, Kathy R

2018-05-18

Recent investigations using cortical auditory evoked potentials have shown masker-dependent effects on sensory cortical processing of speech information. Background noise maskers consisting of other people talking are particularly difficult for speech recognition. Behavioral studies have related this to perceptual masking, or informational masking, beyond just the overlap of the masker and target at the auditory periphery. The aim of the present study was to use cortical auditory evoked potentials, to examine how maskers (i.e., continuous speech-shaped noise [SSN] and multi-talker babble) affect the cortical sensory encoding of speech information at an obligatory level of processing. Specifically, cortical responses to vowel onset and formant change were recorded under different background noise conditions presumed to represent varying amounts of energetic or informational masking. The hypothesis was, that even at this obligatory cortical level of sensory processing, we would observe larger effects on the amplitude and latency of the onset and change components as the amount of informational masking increased across background noise conditions. Onset and change responses were recorded to a vowel change from /u-i/ in young adults under four conditions: quiet, continuous SSN, eight-talker (8T) babble, and two-talker (2T) babble. Repeated measures analyses by noise condition were conducted on amplitude, latency, and response area measurements to determine the differential effects of these noise conditions, designed to represent increasing and varying levels of informational and energetic masking, on cortical neural representation of a vowel onset and acoustic change response waveforms. All noise conditions significantly reduced onset N1 and P2 amplitudes, onset N1-P2 peak to peak amplitudes, as well as both onset and change response area compared with quiet conditions. Further, all amplitude and area measures were significantly reduced for the two babble conditions compared with continuous SSN. However, there were no significant differences in peak amplitude or area for either onset or change responses between the two different babble conditions (eight versus two talkers). Mean latencies for all onset peaks were delayed for noise conditions compared with quiet. However, in contrast to the amplitude and area results, differences in peak latency between SSN and the babble conditions did not reach statistical significance. These results support the idea that while background noise maskers generally reduce amplitude and increase latency of speech-sound evoked cortical responses, the type of masking has a significant influence. Speech babble maskers (eight talkers and two talkers) have a larger effect on the obligatory cortical response to speech sound onset and change compared with purely energetic continuous SSN maskers, which may be attributed to informational masking effects. Neither the neural responses to the onset nor the vowel change, however, were sensitive to the hypothesized increase in the amount of informational masking between speech babble maskers with two talkers compared with eight talkers.

The temporal spectrum of adult mosquito population fluctuations: conceptual and modeling implications.

PubMed

Jian, Yun; Silvestri, Sonia; Brown, Jeff; Hickman, Rick; Marani, Marco

2014-01-01

An improved understanding of mosquito population dynamics under natural environmental forcing requires adequate field observations spanning the full range of temporal scales over which mosquito abundance fluctuates in natural conditions. Here we analyze a 9-year daily time series of uninterrupted observations of adult mosquito abundance for multiple mosquito species in North Carolina to identify characteristic scales of temporal variability, the processes generating them, and the representativeness of observations at different sampling resolutions. We focus in particular on Aedes vexans and Culiseta melanura and, using a combination of spectral analysis and modeling, we find significant population fluctuations with characteristic periodicity between 2 days and several years. Population dynamical modelling suggests that the observed fast fluctuations scales (2 days-weeks) are importantly affected by a varying mosquito activity in response to rapid changes in meteorological conditions, a process neglected in most representations of mosquito population dynamics. We further suggest that the range of time scales over which adult mosquito population variability takes place can be divided into three main parts. At small time scales (indicatively 2 days-1 month) observed population fluctuations are mainly driven by behavioral responses to rapid changes in weather conditions. At intermediate scales (1 to several month) environmentally-forced fluctuations in generation times, mortality rates, and density dependence determine the population characteristic response times. At longer scales (annual to multi-annual) mosquito populations follow seasonal and inter-annual environmental changes. We conclude that observations of adult mosquito populations should be based on a sub-weekly sampling frequency and that predictive models of mosquito abundance must include behavioral dynamics to separate the effects of a varying mosquito activity from actual changes in the abundance of the underlying population.

Mixing and NO(x) Emission Calculations of Confined Reacting Jet Flows in a Cylindrical Duct

NASA Technical Reports Server (NTRS)

Holdeman, James D. (Technical Monitor); Oechsle, Victor L.

2003-01-01

Rapid mixing of cold lateral jets with hot cross-stream flows in confined configurations is of practical interest in gas turbine combustors as it strongly affects combustor exit temperature quality, and gaseous emissions in for example rich-lean combustion. It is therefore important to further improve our fundamental understanding of the important processes of dilution jet mixing especially when the injected jet mass flow rate exceeds that of the cross-stream. The results reported in this report describe some of the main flow characteristics which develop in the mixing process in a cylindrical duct. A 3-dimensional tool has been used to predict the mixing flow field characteristics and NOx emission in a quench section of an RQL combustor, Eighteen configurations have been analyzed in a circular geometry in a fully reacting environment simulating the operating condition of an actual RQL gas turbine combustion liner. The evaluation matrix was constructed by varying three parameters: 1) jet-to-mainstream momentum-flux ratio (J), 2) orifice shape or orifice aspect ratio, and 3) slot slant angle. The results indicate that the mixing flow field significantly varies with the value of the jet penetration and subsequently, slanting elongated slots generally improve the mixing uniformity at high J conditions. Round orifices produce more uniform mixing and low NO(x) emissions at low J due to the strong and adequate jet penetration. No significant correlation was found between the NO(x) production rates and the mixing deviation parameters, however, strong correlation was found between NO(x) formation and jet penetration. In the computational results, most of the NO(x) formation occurred behind the orifice starting at the orifice wake region. Additional NO(x) is formed upstream of the orifice in certain configurations with high J conditions due to the upstream recirculation.

Morning Sleep Inertia in Alertness and Performance: Effect of Cognitive Domain and White Light Conditions

PubMed Central

Santhi, Nayantara; Groeger, John A.; Archer, Simon N.; Gimenez, Marina; Schlangen, Luc J. M.; Dijk, Derk-Jan

2013-01-01

The transition from sleep to wakefulness entails a temporary period of reduced alertness and impaired performance known as sleep inertia. The extent to which its severity varies with task and cognitive processes remains unclear. We examined sleep inertia in alertness, attention, working memory and cognitive throughput with the Karolinska Sleepiness Scale (KSS), the Psychomotor Vigilance Task (PVT), n-back and add tasks, respectively. The tasks were administered 2 hours before bedtime and at regular intervals for four hours, starting immediately after awakening in the morning, in eleven participants, in a four-way cross-over laboratory design. We also investigated whether exposure to Blue-Enhanced or Bright Blue-Enhanced white light would reduce sleep inertia. Alertness and all cognitive processes were impaired immediately upon awakening (p<0.01). However, alertness and sustained attention were more affected than cognitive throughput and working memory. Moreover, speed was more affected than accuracy of responses. The light conditions had no differential effect on performance except in the 3-back task (p<0.01), where response times (RT) at the end of four hours in the two Blue-Enhanced white light conditions were faster (200 ms) than at wake time. We conclude that the effect of sleep inertia varies with cognitive domain and that it’s spectral/intensity response to light is different from that of sleepiness. That is, just increasing blue-wavelength in light may not be sufficient to reduce sleep inertia. These findings have implications for critical professions like medicine, law-enforcement etc., in which, personnel routinely wake up from night-time sleep to respond to emergency situations. PMID:24260280

Assessment and manifestation of central sensitisation across different chronic pain conditions.

PubMed

Arendt-Nielsen, L; Morlion, B; Perrot, S; Dahan, A; Dickenson, A; Kress, H G; Wells, C; Bouhassira, D; Mohr Drewes, A

2018-02-01

Different neuroplastic processes can occur along the nociceptive pathways and may be important in the transition from acute to chronic pain and for diagnosis and development of optimal management strategies. The neuroplastic processes may result in gain (sensitisation) or loss (desensitisation) of function in relation to the incoming nociceptive signals. Such processes play important roles in chronic pain, and although the clinical manifestations differ across condition processes, they share some common mechanistic features. The fundamental understanding and quantitative assessment of particularly some of the central sensitisation mechanisms can be translated from preclinical studies into the clinic. The clinical perspectives are implementation of such novel information into diagnostics, mechanistic phenotyping, prevention, personalised treatment, and drug development. The aims of this paper are to introduce and discuss (1) some common fundamental central pain mechanisms, (2) how they may translate into the clinical signs and symptoms across different chronic pain conditions, (3) how to evaluate gain and loss of function using quantitative pain assessment tools, and (4) the implications for optimising prevention and management of pain. The chronic pain conditions selected for the paper are neuropathic pain in general, musculoskeletal pain (chronic low back pain and osteoarthritic pain in particular), and visceral pain (irritable bowel syndrome in particular). The translational mechanisms addressed are local and widespread sensitisation, central summation, and descending pain modulation. Central sensitisation is an important manifestation involved in many different chronic pain conditions. Central sensitisation can be different to assess and evaluate as the manifestations vary from pain condition to pain condition. Understanding central sensitisation may promote better profiling and diagnosis of pain patients and development of new regimes for mechanism based therapy. Some of the mechanisms underlying central sensitisation can be translated from animals to humans providing new options in development of therapies and profiling drugs under development. © 2017 European Pain Federation - EFIC®.

Cortical Activation in Response to Pure Taste Stimuli During the Physiological States of Hunger and Satiety

PubMed Central

Haase, Lori; Cerf-Ducastel, Barbara; Murphy, Claire

2009-01-01

This event-related functional magnetic resonance imaging (er-fMRI) study investigated BOLD signal change in response to a series of pure gustatory stimuli that varied in stimulus quality when subjects were hungry and sated with a nutritional preload. Group analyses showed significant differences in activation in the hunger minus satiety condition in response to sucrose, caffeine, saccharin, and citric acid within the thalamus, hippocampus, and parahippocampus. When examining the hunger and satiety conditions, activation varied as a function of stimulus, with the majority of the stimuli exhibiting significantly greater activation in the hunger state within the insula, thalamus, and substantia nigra, in contrast to decreased activation in the satiated state within the parahippocampus, hippocampus, amygdala, and anterior cingulate. Region of interest (ROI) analysis revealed two significant interactions, ROI by physiology and ROI by physiology by stimulus. In the satiety condition, the primary (inferior and superior insulae) and secondary (OFC 11 and OFC 47) taste regions exhibited significantly greater brain activation in response to all stimuli than regions involved in processing eating behavior (hypothalamus), affect (amygdala), and memory (hippocampus, parahippocampus and entorhinal cortex). These same regions demonstrated significantly greater activation within the hunger condition than the satiety condition, with the exception of the superior insula. Furthermore, the patterns of activation differed as a function taste stimulus, with greater activation in response to sucrose than to the other stimuli. These differential patterns of activation suggest that the physiological states of hunger and satiety produce divergent activation in multiple brain areas in response to different pure gustatory stimuli. PMID:19007893

Cortical activation in response to pure taste stimuli during the physiological states of hunger and satiety.

PubMed

Haase, Lori; Cerf-Ducastel, Barbara; Murphy, Claire

2009-02-01

This event-related functional magnetic resonance imaging (er-fMRI) study investigated BOLD signal change in response to a series of pure gustatory stimuli that varied in stimulus quality when subjects were hungry and sated with a nutritional pre-load. Group analyses showed significant differences in activation in the hunger minus satiety condition in response to sucrose, caffeine, saccharin, and citric acid within the thalamus, hippocampus, and parahippocampus. When examining the hunger and satiety conditions, activation varied as a function of stimulus, with the majority of the stimuli exhibiting significantly greater activation in the hunger state within the insula, thalamus, and substantia nigra, in contrast to decreased activation in the satiated state within the parahippocampus, hippocampus, amygdala, and anterior cingulate. Region of interest (ROI) analysis revealed two significant interactions, ROI by physiology and ROI by physiology by stimulus. In the satiety condition, the primary (inferior and superior insulae) and secondary (OFC 11 and OFC 47) taste regions exhibited significantly greater brain activation in response to all stimuli than regions involved in processing eating behavior (hypothalamus), affect (amygdala), and memory (hippocampus, parahippocampus and entorhinal cortex). These same regions demonstrated significantly greater activation within the hunger condition than the satiety condition, with the exception of the superior insula. Furthermore, the patterns of activation differed as a function taste stimulus, with greater activation in response to sucrose than to the other stimuli. These differential patterns of activation suggest that the physiological states of hunger and satiety produce divergent activation in multiple brain areas in response to different pure gustatory stimuli.

Fuel conditioning facility zone-to-zone transfer administrative controls.

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

Pope, C. L.

2000-06-21

The administrative controls associated with transferring containers from one criticality hazard control zone to another in the Argonne National Laboratory (ANL) Fuel Conditioning Facility (FCF) are described. FCF, located at the ANL-West site near Idaho Falls, Idaho, is used to remotely process spent sodium bonded metallic fuel for disposition. The process involves nearly forty widely varying material forms and types, over fifty specific use container types, and over thirty distinct zones where work activities occur. During 1999, over five thousand transfers from one zone to another were conducted. Limits are placed on mass, material form and type, and container typesmore » for each zone. Ml material and containers are tracked using the Mass Tracking System (MTG). The MTG uses an Oracle database and numerous applications to manage the database. The database stores information specific to the process, including material composition and mass, container identification number and mass, transfer history, and the operators involved in each transfer. The process is controlled using written procedures which specify the zone, containers, and material involved in a task. Transferring a container from one zone to another is called a zone-to-zone transfer (ZZT). ZZTs consist of four distinct phases, select, request, identify, and completion.« less

Synaptic consolidation as a temporally variable process: Uncovering the parameters modulating its time-course.

PubMed

Casagrande, Mirelle A; Haubrich, Josué; Pedraza, Lizeth K; Popik, Bruno; Quillfeldt, Jorge A; de Oliveira Alvares, Lucas

2018-04-01

Memories are not instantly created in the brain, requiring a gradual stabilization process called consolidation to be stored and persist in a long-lasting manner. However, little is known whether this time-dependent process is dynamic or static, and the factors that might modulate it. Here, we hypothesized that the time-course of consolidation could be affected by specific learning parameters, changing the time window where memory is susceptible to retroactive interference. In the rodent contextual fear conditioning paradigm, we compared weak and strong training protocols and found that in the latter memory is susceptible to post-training hippocampal inactivation for a shorter period of time. The accelerated consolidation process triggered by the strong training was mediated by glucocorticoids, since this effect was blocked by pre-training administration of metyrapone. In addition, we found that pre-exposure to the training context also accelerates fear memory consolidation. Hence, our results demonstrate that the time window in which memory is susceptible to post-training interferences varies depending on fear conditioning intensity and contextual familiarity. We propose that the time-course of memory consolidation is dynamic, being directly affected by attributes of the learning experiences. Copyright © 2018 Elsevier Inc. All rights reserved.

Oxidative processes in soybean and pea seeds: effect of light, temperature, and water content

NASA Technical Reports Server (NTRS)

Vertucci, C. W.; Leopold, A. C.

1987-01-01

Oxidative processes are probable determinants of longevity of seeds in storage. Measurements of actual oxygen uptake rates were made for soybean and pea seeds as a comparison of short and long lived seeds when light, temperature, and moisture contents were varied. In both peas and soybeans, the oxygen uptake was depressed at low temperatures (<16 degrees C) and low water contents (< 0.25 gram H2O per gram dry weight). Apparent activation energies under these conditions are very high, while apparent activation energies of seeds at higher water contents and at temperatures greater than 22 degrees C are much less. Light enhances the level of oxygen uptake in pea, but reduces the level of oxygen uptake in soybean. The complexities of the interactions of oxygen uptake with environmental conditions in soybean compared to pea suggest that oxidative processes occur in soybean at low water contents, but are essentially absent in pea. It is suggested that the additional oxidative processes in soybean with moisture contents between 0.10 and 0.24 gram per gram may contribute to the poorer longevity of soybean seed compared to pea seed.

Disentangling the Role of Entanglement Density and Molecular Alignment in the Mechanical Response of Glassy Polymers

NASA Astrophysics Data System (ADS)

O'Connor, Thomas; Robbins, Mark

Glassy polymers are a ubiquitous part of modern life, but much about their mechanical properties remains poorly understood. Since chains in glassy states are hindered from exploring their conformational entropy, they can't be understood with common entropic network models. Additionally, glassy states are highly sensitive to material history and nonequilibrium distributions of chain alignment and entanglement can be produced during material processing. Understanding how these far-from equilibrium states impact mechanical properties is analytically challenging but essential to optimizing processing methods. We use molecular dynamics simulations to study the yield and strain hardening of glassy polymers as separate functions of the degree of molecular alignment and inter-chain entanglement. We vary chain alignment and entanglement with three different preparation protocols that mimic common processing conditions in and out of solution. We compare our results to common mechanical models of amorphous polymers and assess their applicability to different experimental processing conditions. This research was performed within the Center for Materials in Extreme Dynamic Environments (CMEDE) under the Hopkins Extreme Materials Institute at Johns Hopkins University. Financial support was provided by Grant W911NF-12-2-0022.

Study of recombination characteristics in MOCVD grown GaN epi-layers on Si

NASA Astrophysics Data System (ADS)

Gaubas, E.; Ceponis, T.; Dobrovolskas, D.; Malinauskas, T.; Meskauskaite, D.; Miasojedovas, S.; Mickevicius, J.; Pavlov, J.; Rumbauskas, V.; Simoen, E.; Zhao, M.

2017-12-01

The radiative and non-radiative recombination carrier decay lifetimes in GaN epi-layers grown by metal-organic chemical vapour deposition technology on Si substrates were measured by contactless techniques of time-resolved photoluminescence and microwave-probed transients of photoconductivity. The lifetime variations were obtained to be dependent on growth regimes. These variations have been related to varied densities of edge dislocations associated with growth temperature. It has been also revealed that the lateral carrier lifetime and photoluminescence intensity distribution is determined by the formation of dislocation clusters dependent on the growth conditions. For low excitation level, the asymptotic component within the excess carrier decay transients is attributed to carrier trapping and anomalous diffusion through random-walk processes within dislocation cluster regions and barriers at dislocation cores. The two-componential decay process at high excitation conditions, where excess carriers may suppress barriers, proceeds through a nonlinear recombination, where band-to-band transitions determine the nonlinearity of the process, while the asymptotic component is ascribed to the impact of D-A pair PL within the long-wavelength wing of the UV-PL band.

New Evidence for Strategic Differences between Static and Dynamic Search Tasks: An Individual Observer Analysis of Eye Movements

PubMed Central

Dickinson, Christopher A.; Zelinsky, Gregory J.

2013-01-01

Two experiments are reported that further explore the processes underlying dynamic search. In Experiment 1, observers’ oculomotor behavior was monitored while they searched for a randomly oriented T among oriented L distractors under static and dynamic viewing conditions. Despite similar search slopes, eye movements were less frequent and more spatially constrained under dynamic viewing relative to static, with misses also increasing more with target eccentricity in the dynamic condition. These patterns suggest that dynamic search involves a form of sit-and-wait strategy in which search is restricted to a small group of items surrounding fixation. To evaluate this interpretation, we developed a computational model of a sit-and-wait process hypothesized to underlie dynamic search. In Experiment 2 we tested this model by varying fixation position in the display and found that display positions optimized for a sit-and-wait strategy resulted in higher d′ values relative to a less optimal location. We conclude that different strategies, and therefore underlying processes, are used to search static and dynamic displays. PMID:23372555

Glass fiber dissolution in simulated lung fluid and measures needed to improve consistency and correspondence to in vivo dissolution.

PubMed Central

Mattson, S M

1994-01-01

The dissolution of a range of glass fibers including commercial glass and mineral wools has been studied using a modification of Gamble's solution in a flow system at pH 7.4 and 37 degrees C. Dissolution has been followed by weight loss, effluent analysis, and morphology change of fibers and bulk glass. Flow per glass surface area can strongly affect both dissolution rate and morphology due to the effect of the dissolution process on the fluid. Effluent pH is shown to be a guide for choice of optimum flow/area conditions. These conditions provide measurable concentrations of dissolved glass in the effluent while maintaining their concentrations below the point at which they significantly affect the dissolution process. SiO2 and Al2O3 vary widely in the extent to which they are involved in the leaching process, which removes alkalis, alkaline earths, and B2O3. This makes analysis of a single component in the effluent unsuitable as a means of comparing the dissolution rates of a wide range of compositions. PMID:7882963

Sulfide and methane production in sewer sediments: Field survey and model evaluation.

PubMed

Liu, Yiwen; Tugtas, A Evren; Sharma, Keshab R; Ni, Bing-Jie; Yuan, Zhiguo

2016-02-01

Sewer sediment processes have been reported to significantly contribute to overall sulfide and methane production in sewers, at a scale comparable to that of sewer biofilms. The physiochemical and biological characteristics of sewer sediments are heterogeneous; however, the variability of in-sediments sulfide and methane production rates among sewers has not been assessed to date. In this study, five sewer sediment samples were collected from two cities in Australia with different climatic conditions. Batch assays were conducted to determine the rates of sulfate reduction and methane production under different flow velocity (shear stress) conditions as well as under completely mixed conditions. The tests showed substantial and variable sulfate reduction and methane production activities among different sediments. Sulfate reduction and methane production from sewer sediments were confirmed to be areal processes, and were dependent on flow velocity/shear stress. Despite of the varying characteristics and reactions kinetics, the sulfate reduction and methane production processes in all sediments could be well described by a one-dimensional sewer sediment model recently developed based on results obtained from a laboratory sewer sediment reactor. Model simulations indicated that the in-situ contribution of sewer sediment emissions could be estimated without the requirement of measuring the specific sediment characteristics or the sediment depths. Copyright © 2015 Elsevier Ltd. All rights reserved.

Microbial production of scleroglucan and downstream processing.

PubMed

Castillo, Natalia A; Valdez, Alejandra L; Fariña, Julia I

2015-01-01

Synthetic petroleum-based polymers and natural plant polymers have the disadvantage of restricted sources, in addition to the non-biodegradability of the former ones. In contrast, eco-sustainable microbial polysaccharides, of low-cost and standardized production, represent an alternative to address this situation. With a strong global market, they attracted worldwide attention because of their novel and unique physico-chemical properties as well as varied industrial applications, and many of them are promptly becoming economically competitive. Scleroglucan, a β-1,3-β-1,6-glucan secreted by Sclerotium fungi, exhibits high potential for commercialization and may show different branching frequency, side-chain length, and/or molecular weight depending on the producing strain or culture conditions. Water-solubility, viscosifying ability and wide stability over temperature, pH and salinity make scleroglucan useful for different biotechnological (enhanced oil recovery, food additives, drug delivery, cosmetic and pharmaceutical products, biocompatible materials, etc.), and biomedical (immunoceutical, antitumor, etc.) applications. It can be copiously produced at bioreactor scale under standardized conditions, where a high exopolysaccharide concentration normally governs the process optimization. Operative and nutritional conditions, as well as the incidence of scleroglucan downstream processing will be discussed in this chapter. The relevance of using standardized inocula from selected strains and experiences concerning the intricate scleroglucan scaling-up will be also herein outlined.

Working memory deficits in boys with attention deficit/hyperactivity disorder (ADHD): An examination of orthographic coding and episodic buffer processes.

PubMed

Alderson, R Matt; Kasper, Lisa J; Patros, Connor H G; Hudec, Kristen L; Tarle, Stephanie J; Lea, Sarah E

2015-01-01

The episodic buffer component of working memory was examined in children with attention deficit/hyperactivity disorder (ADHD) and typically developing peers (TD). Thirty-two children (ADHD = 16, TD = 16) completed three versions of a phonological working memory task that varied with regard to stimulus presentation modality (auditory, visual, or dual auditory and visual), as well as a visuospatial task. Children with ADHD experienced the largest magnitude working memory deficits when phonological stimuli were presented via a unimodal, auditory format. Their performance improved during visual and dual modality conditions but remained significantly below the performance of children in the TD group. In contrast, the TD group did not exhibit performance differences between the auditory- and visual-phonological conditions but recalled significantly more stimuli during the dual-phonological condition. Furthermore, relative to TD children, children with ADHD recalled disproportionately fewer phonological stimuli as set sizes increased, regardless of presentation modality. Finally, an examination of working memory components indicated that the largest magnitude between-group difference was associated with the central executive. Collectively, these findings suggest that ADHD-related working memory deficits reflect a combination of impaired central executive and phonological storage/rehearsal processes, as well as an impaired ability to benefit from bound multimodal information processed by the episodic buffer.

Microbial production of scleroglucan and downstream processing

PubMed Central

Castillo, Natalia A.; Valdez, Alejandra L.; Fariña, Julia I.

2015-01-01

Synthetic petroleum-based polymers and natural plant polymers have the disadvantage of restricted sources, in addition to the non-biodegradability of the former ones. In contrast, eco-sustainable microbial polysaccharides, of low-cost and standardized production, represent an alternative to address this situation. With a strong global market, they attracted worldwide attention because of their novel and unique physico-chemical properties as well as varied industrial applications, and many of them are promptly becoming economically competitive. Scleroglucan, a β-1,3-β-1,6-glucan secreted by Sclerotium fungi, exhibits high potential for commercialization and may show different branching frequency, side-chain length, and/or molecular weight depending on the producing strain or culture conditions. Water-solubility, viscosifying ability and wide stability over temperature, pH and salinity make scleroglucan useful for different biotechnological (enhanced oil recovery, food additives, drug delivery, cosmetic and pharmaceutical products, biocompatible materials, etc.), and biomedical (immunoceutical, antitumor, etc.) applications. It can be copiously produced at bioreactor scale under standardized conditions, where a high exopolysaccharide concentration normally governs the process optimization. Operative and nutritional conditions, as well as the incidence of scleroglucan downstream processing will be discussed in this chapter. The relevance of using standardized inocula from selected strains and experiences concerning the intricate scleroglucan scaling-up will be also herein outlined. PMID:26528259

In-process, non-destructive multimodal dynamic testing of high-speed composite rotors

NASA Astrophysics Data System (ADS)

Kuschmierz, Robert; Filippatos, Angelos; Langkamp, Albert; Hufenbach, Werner; Czarske, Jürgern W.; Fischer, Andreas

2014-03-01

Fibre reinforced plastic (FRP) rotors are lightweight and offer great perspectives in high-speed applications such as turbo machinery. Currently, novel rotor structures and materials are investigated for the purpose of increasing machine efficiency, lifetime and loading limits. Due to complex rotor structures, high anisotropy and non-linear behavior of FRP under dynamic loads, an in-process measurement system is necessary to monitor and to investigate the evolution of damages under real operation conditions. A non-invasive, optical laser Doppler distance sensor measurement system is applied to determine the biaxial deformation of a bladed FRP rotor with micron uncertainty as well as the tangential blade vibrations at surface speeds above 300 m/s. The laser Doppler distance sensor is applicable under vacuum conditions. Measurements at varying loading conditions are used to determine elastic and plastic deformations. Furthermore they allow to determine hysteresis, fatigue, Eigenfrequency shifts and loading limits. The deformation measurements show a highly anisotropic and nonlinear behavior and offer a deeper understanding of the damage evolution in FRP rotors. The experimental results are used to validate and to calibrate a simulation model of the deformation. The simulation combines finite element analysis and a damage mechanics model. The combination of simulation and measurement system enables the monitoring and prediction of damage evolutions of FRP rotors in process.

Timing matters: the processing of pitch relations

PubMed Central

Weise, Annekathrin; Grimm, Sabine; Trujillo-Barreto, Nelson J.; Schröger, Erich

2014-01-01

The human central auditory system can automatically extract abstract regularities from a variant auditory input. To this end, temporarily separated events need to be related. This study tested whether the timing between events, falling either within or outside the temporal window of integration (~350 ms), impacts the extraction of abstract feature relations. We utilized tone pairs for which tones within but not across pairs revealed a constant pitch relation (e.g., pitch of second tone of a pair higher than pitch of first tone, while absolute pitch values varied across pairs). We measured the mismatch negativity (MMN; the brain’s error signal to auditory regularity violations) to second tones that rarely violated the pitch relation (e.g., pitch of second tone lower). A Short condition in which tone duration (90 ms) and stimulus onset asynchrony between the tones of a pair were short (110 ms) was compared to two conditions, where this onset asynchrony was long (510 ms). In the Long Gap condition, the tone durations were identical to Short (90 ms), but the silent interval was prolonged by 400 ms. In Long Tone, the duration of the first tone was prolonged by 400 ms, while the silent interval was comparable to Short (20 ms). Results show a frontocentral MMN of comparable amplitude in all conditions. Thus, abstract pitch relations can be extracted even when the within-pair timing exceeds the integration period. Source analyses indicate MMN generators in the supratemporal cortex. Interestingly, they were located more anterior in Long Gap than in Short and Long Tone. Moreover, frontal generator activity was found for Long Gap and Long Tone. Thus, the way in which the system automatically registers irregular abstract pitch relations depends on the timing of the events to be linked. Pending that the current MMN data mirror established abstract rule representations coding the regular pitch relation, neural processes building these templates vary with timing. PMID:24966823

Audio-Visual Perception of 3D Cinematography: An fMRI Study Using Condition-Based and Computation-Based Analyses

PubMed Central

Ogawa, Akitoshi; Bordier, Cecile; Macaluso, Emiliano

2013-01-01

The use of naturalistic stimuli to probe sensory functions in the human brain is gaining increasing interest. Previous imaging studies examined brain activity associated with the processing of cinematographic material using both standard “condition-based” designs, as well as “computational” methods based on the extraction of time-varying features of the stimuli (e.g. motion). Here, we exploited both approaches to investigate the neural correlates of complex visual and auditory spatial signals in cinematography. In the first experiment, the participants watched a piece of a commercial movie presented in four blocked conditions: 3D vision with surround sounds (3D-Surround), 3D with monaural sound (3D-Mono), 2D-Surround, and 2D-Mono. In the second experiment, they watched two different segments of the movie both presented continuously in 3D-Surround. The blocked presentation served for standard condition-based analyses, while all datasets were submitted to computation-based analyses. The latter assessed where activity co-varied with visual disparity signals and the complexity of auditory multi-sources signals. The blocked analyses associated 3D viewing with the activation of the dorsal and lateral occipital cortex and superior parietal lobule, while the surround sounds activated the superior and middle temporal gyri (S/MTG). The computation-based analyses revealed the effects of absolute disparity in dorsal occipital and posterior parietal cortices and of disparity gradients in the posterior middle temporal gyrus plus the inferior frontal gyrus. The complexity of the surround sounds was associated with activity in specific sub-regions of S/MTG, even after accounting for changes of sound intensity. These results demonstrate that the processing of naturalistic audio-visual signals entails an extensive set of visual and auditory areas, and that computation-based analyses can track the contribution of complex spatial aspects characterizing such life-like stimuli. PMID:24194828

Audio-visual perception of 3D cinematography: an fMRI study using condition-based and computation-based analyses.

PubMed

Ogawa, Akitoshi; Bordier, Cecile; Macaluso, Emiliano

2013-01-01

The use of naturalistic stimuli to probe sensory functions in the human brain is gaining increasing interest. Previous imaging studies examined brain activity associated with the processing of cinematographic material using both standard "condition-based" designs, as well as "computational" methods based on the extraction of time-varying features of the stimuli (e.g. motion). Here, we exploited both approaches to investigate the neural correlates of complex visual and auditory spatial signals in cinematography. In the first experiment, the participants watched a piece of a commercial movie presented in four blocked conditions: 3D vision with surround sounds (3D-Surround), 3D with monaural sound (3D-Mono), 2D-Surround, and 2D-Mono. In the second experiment, they watched two different segments of the movie both presented continuously in 3D-Surround. The blocked presentation served for standard condition-based analyses, while all datasets were submitted to computation-based analyses. The latter assessed where activity co-varied with visual disparity signals and the complexity of auditory multi-sources signals. The blocked analyses associated 3D viewing with the activation of the dorsal and lateral occipital cortex and superior parietal lobule, while the surround sounds activated the superior and middle temporal gyri (S/MTG). The computation-based analyses revealed the effects of absolute disparity in dorsal occipital and posterior parietal cortices and of disparity gradients in the posterior middle temporal gyrus plus the inferior frontal gyrus. The complexity of the surround sounds was associated with activity in specific sub-regions of S/MTG, even after accounting for changes of sound intensity. These results demonstrate that the processing of naturalistic audio-visual signals entails an extensive set of visual and auditory areas, and that computation-based analyses can track the contribution of complex spatial aspects characterizing such life-like stimuli.

Dry Ribbon for Heated Head Automated Fiber Placement

NASA Technical Reports Server (NTRS)

Hulcher, A. Bruce; Marchello, Joseph M.; Hinkley, Jeffrey A.; Johnston, Norman J.; Lamontia, Mark A.

2000-01-01

Ply-by-ply in situ processes involving automated heated head deposition are being developed for fabrication of high performance, high temperature composite structures from low volatile content polymer matrices. This technology requires (1) dry carbon fiber towpreg, (2) consolidation of towpreg to quality, placement-grade unidirectional ribbon or tape, and (3) rapid, in situ, accurate, ply-by-ply robotic placement and consolidation of this material to fabricate a composite structure. In this study, the physical properties of a candidate thermoplastic ribbon, PIXA/IM7, were evaluated and screened for suitability in robotic placement. Specifically, towpreg was prepared from PIXA powder. Various conditions (temperatures) were used to convert the powder-coated towpreg to ribbons with varying degrees of processability. Ribbon within preset specifications was fabricated at 3 temperatures: 390, 400 and 410 C. Ribbon was also produced out-of-spec by purposely overheating the material to a processing temperature of 450 C. Automated placement equipment at Cincinnati Milacron and NASA Langley was used to fabricate laminates from these experimental ribbons. Ribbons were placed at 405 and 450 C by both sets of equipment. Double cantilever beam and wedge peel tests were used to determine the quality of the laminates and, especially, the interlaminar bond formed during the placement process. Ribbon made under conditions expected to be non-optimal (overheated) resulted in poor placeability and composites with weak interlaminar bond strengths, regardless of placement conditions. Ribbon made under conditions expected to be ideal showed good processability and produced well-consolidated laminates. Results were consistent from machine to machine and demonstrated the importance of ribbon quality in heated-head placement of dry material forms. Preliminary screening criteria for the development and evaluation of ribbon from new matrix materials were validated.

Evolution of Pediatric Chronic Disease Treatment Decisions: A Qualitative, Longitudinal View of Parents' Decision-Making Process.

PubMed

Lipstein, Ellen A; Britto, Maria T

2015-08-01

In the context of pediatric chronic conditions, patients and families are called upon repeatedly to make treatment decisions. However, little is known about how their decision making evolves over time. The objective was to understand parents' processes for treatment decision making in pediatric chronic conditions. We conducted a qualitative, prospective longitudinal study using recorded clinic visits and individual interviews. After consent was obtained from health care providers, parents, and patients, clinic visits during which treatment decisions were expected to be discussed were video-recorded. Parents then participated in sequential telephone interviews about their decision-making experience. Data were coded by 2 people and analyzed using framework analysis with sequential, time-ordered matrices. 21 families, including 29 parents, participated in video-recording and interviews. We found 3 dominant patterns of decision evolution. Each consisted of a series of decision events, including conversations, disease flares, and researching of treatment options. Within all 3 patterns there were both constant and evolving elements of decision making, such as role perceptions and treatment expectations, respectively. After parents made a treatment decision, they immediately turned to the next decision related to the chronic condition, creating an iterative cycle. In this study, decision making was an iterative process occurring in 3 distinct patterns. Understanding these patterns and the varying elements of parents' decision processes is an essential step toward developing interventions that are appropriate to the setting and that capitalize on the skills families may develop as they gain experience with a chronic condition. Future research should also consider the role of children and adolescents in this decision process. © The Author(s) 2015.

Explicit attention interferes with selective emotion processing in human extrastriate cortex.

PubMed

Schupp, Harald T; Stockburger, Jessica; Bublatzky, Florian; Junghöfer, Markus; Weike, Almut I; Hamm, Alfons O

2007-02-22

Brain imaging and event-related potential studies provide strong evidence that emotional stimuli guide selective attention in visual processing. A reflection of the emotional attention capture is the increased Early Posterior Negativity (EPN) for pleasant and unpleasant compared to neutral images (approximately 150-300 ms poststimulus). The present study explored whether this early emotion discrimination reflects an automatic phenomenon or is subject to interference by competing processing demands. Thus, emotional processing was assessed while participants performed a concurrent feature-based attention task varying in processing demands. Participants successfully performed the primary visual attention task as revealed by behavioral performance and selected event-related potential components (Selection Negativity and P3b). Replicating previous results, emotional modulation of the EPN was observed in a task condition with low processing demands. In contrast, pleasant and unpleasant pictures failed to elicit increased EPN amplitudes compared to neutral images in more difficult explicit attention task conditions. Further analyses determined that even the processing of pleasant and unpleasant pictures high in emotional arousal is subject to interference in experimental conditions with high task demand. Taken together, performing demanding feature-based counting tasks interfered with differential emotion processing indexed by the EPN. The present findings demonstrate that taxing processing resources by a competing primary visual attention task markedly attenuated the early discrimination of emotional from neutral picture contents. Thus, these results provide further empirical support for an interference account of the emotion-attention interaction under conditions of competition. Previous studies revealed the interference of selective emotion processing when attentional resources were directed to locations of explicitly task-relevant stimuli. The present data suggest that interference of emotion processing by competing task demands is a more general phenomenon extending to the domain of feature-based attention. Furthermore, the results are inconsistent with the notion of effortlessness, i.e., early emotion discrimination despite concurrent task demands. These findings implicate to assess the presumed automatic nature of emotion processing at the level of specific aspects rather than considering automaticity as an all-or-none phenomenon.

Explicit attention interferes with selective emotion processing in human extrastriate cortex

PubMed Central

Schupp, Harald T; Stockburger, Jessica; Bublatzky, Florian; Junghöfer, Markus; Weike, Almut I; Hamm, Alfons O

2007-01-01

Background Brain imaging and event-related potential studies provide strong evidence that emotional stimuli guide selective attention in visual processing. A reflection of the emotional attention capture is the increased Early Posterior Negativity (EPN) for pleasant and unpleasant compared to neutral images (~150–300 ms poststimulus). The present study explored whether this early emotion discrimination reflects an automatic phenomenon or is subject to interference by competing processing demands. Thus, emotional processing was assessed while participants performed a concurrent feature-based attention task varying in processing demands. Results Participants successfully performed the primary visual attention task as revealed by behavioral performance and selected event-related potential components (Selection Negativity and P3b). Replicating previous results, emotional modulation of the EPN was observed in a task condition with low processing demands. In contrast, pleasant and unpleasant pictures failed to elicit increased EPN amplitudes compared to neutral images in more difficult explicit attention task conditions. Further analyses determined that even the processing of pleasant and unpleasant pictures high in emotional arousal is subject to interference in experimental conditions with high task demand. Taken together, performing demanding feature-based counting tasks interfered with differential emotion processing indexed by the EPN. Conclusion The present findings demonstrate that taxing processing resources by a competing primary visual attention task markedly attenuated the early discrimination of emotional from neutral picture contents. Thus, these results provide further empirical support for an interference account of the emotion-attention interaction under conditions of competition. Previous studies revealed the interference of selective emotion processing when attentional resources were directed to locations of explicitly task-relevant stimuli. The present data suggest that interference of emotion processing by competing task demands is a more general phenomenon extending to the domain of feature-based attention. Furthermore, the results are inconsistent with the notion of effortlessness, i.e., early emotion discrimination despite concurrent task demands. These findings implicate to assess the presumed automatic nature of emotion processing at the level of specific aspects rather than considering automaticity as an all-or-none phenomenon. PMID:17316444

Brain oscillatory subsequent memory effects differ in power and long-range synchronization between semantic and survival processing.

PubMed

Fellner, Marie-Christin; Bäuml, Karl-Heinz T; Hanslmayr, Simon

2013-10-01

Memory crucially depends on the way information is processed during encoding. Differences in processes during encoding not only lead to differences in memory performance but also rely on different brain networks. Although these assumptions are corroborated by several previous fMRI and ERP studies, little is known about how brain oscillations dissociate between different memory encoding tasks. The present study therefore compared encoding related brain oscillatory activity elicited by two very efficient encoding tasks: a typical deep semantic item feature judgment task and a more elaborative survival encoding task. Subjects were asked to judge words either for survival relevance or for animacy, as indicated by a cue presented prior to the item. This allowed dissociating pre-item activity from item-related activity for both tasks. Replicating prior studies, survival processing led to higher recognition performance than semantic processing. Successful encoding in the semantic condition was reflected by a strong decrease in alpha and beta power, whereas successful encoding in the survival condition was related to increased alpha and beta long-range phase synchrony. Moreover, a pre-item subsequent memory effect in theta power was found which did not vary with encoding condition. These results show that measures of local synchrony (power) and global long range-synchrony (phase synchronization) dissociate between memory encoding processes. Whereas semantic encoding was reflected in decreases in local synchrony, increases in global long range synchrony were related to elaborative survival encoding, presumably reflecting the involvement of a more widespread cortical network in this task. Copyright © 2013 Elsevier Inc. All rights reserved.

Ecological niche models reveal the importance of climate variability for the biogeography of protosteloid amoebae

PubMed Central

Aguilar, María; Lado, Carlos

2012-01-01

Habitat availability and environmental preferences of species are among the most important factors in determining the success of dispersal processes and therefore in shaping the distribution of protists. We explored the differences in fundamental niches and potential distributions of an ecological guild of slime moulds—protosteloid amoebae—in the Iberian Peninsula. A large set of samples collected in a north-east to south-west transect of approximately 1000 km along the peninsula was used to test the hypothesis that, together with the existence of suitable microhabitats, climate conditions may determine the probability of survival of species. Although protosteloid amoebae share similar morphologies and life history strategies, canonical correspondence analyses showed that they have varied ecological optima, and that climate conditions have an important effect in niche differentiation. Maxent environmental niche models provided consistent predictions of the probability of presence of the species based on climate data, and they were used to generate maps of potential distribution in an ‘everything is everywhere' scenario. The most important climatic factors were, in both analyses, variables that measure changes in conditions throughout the year, confirming that the alternation of fruiting bodies, cysts and amoeboid stages in the life cycles of protosteloid amoebae constitutes an advantage for surviving in a changing environment. Microhabitat affinity seems to be influenced by climatic conditions, which suggests that the micro-environment may vary at a local scale and change together with the external climate at a larger scale. PMID:22402402

Ecological niche models reveal the importance of climate variability for the biogeography of protosteloid amoebae.

PubMed

Aguilar, María; Lado, Carlos

2012-08-01

Habitat availability and environmental preferences of species are among the most important factors in determining the success of dispersal processes and therefore in shaping the distribution of protists. We explored the differences in fundamental niches and potential distributions of an ecological guild of slime moulds-protosteloid amoebae-in the Iberian Peninsula. A large set of samples collected in a north-east to south-west transect of approximately 1000 km along the peninsula was used to test the hypothesis that, together with the existence of suitable microhabitats, climate conditions may determine the probability of survival of species. Although protosteloid amoebae share similar morphologies and life history strategies, canonical correspondence analyses showed that they have varied ecological optima, and that climate conditions have an important effect in niche differentiation. Maxent environmental niche models provided consistent predictions of the probability of presence of the species based on climate data, and they were used to generate maps of potential distribution in an 'everything is everywhere' scenario. The most important climatic factors were, in both analyses, variables that measure changes in conditions throughout the year, confirming that the alternation of fruiting bodies, cysts and amoeboid stages in the life cycles of protosteloid amoebae constitutes an advantage for surviving in a changing environment. Microhabitat affinity seems to be influenced by climatic conditions, which suggests that the micro-environment may vary at a local scale and change together with the external climate at a larger scale.

Contamination-Free Sonoreactor for the Food Industry

NASA Astrophysics Data System (ADS)

Dion, Jean-Luc

A new sonoreactor technology is presented here, which should open vast development possibilities in various fields of chemical, pharmaceutical, and food industries. It should give a decisive impulse to sonochemistry in these various areas. These exclusive systems use high-power converging acoustic waves in a tube to produce a relatively large volume confined acoustic cavitation zone in flowing liquid reagents. It is well known that numerous chemical reactions are strongly accelerated when they take place inside such a zone. The new cylindrical sonoreactors do not contaminate the processed liquids with erosion products as other devices do. The processing conditions can be widely varied with pressure, power, temperature, and flow rate. The processing capacity of the largest models may be up to several tons per hour, using an electric power input of about 50 kW.

Dominierende Prozesse bei der thermischen In-situ-Sanierung (TISS) kontaminierter Geringleiter

NASA Astrophysics Data System (ADS)

Hiester, Uwe; Bieber, Laura

2017-09-01

Contaminants such as chlorinated, aromatic or polycyclic aromatic hydrocarbons (CHC, BTEX, PAH) or mineral oil hydrocarbons (TPH) constitute a prevalent threat to water resources. The significant storage capacity of low permeable soils (aquitards) leads to their long-term contamination. In situ thermal remediation (ISTR) proved to work successfully in treating these soils. Thus, the area of ISTR application grew continuously over the past 10 years. The dominating processes during the remediation can vary considerably, depending on hydrogeological and geological boundary conditions and the contamination itself. This article summarizes the application for in-situ thermal remediation (ISTR) in low permeable soils and aquitards for soil and groundwater treatment. Dominating remediation processes during volatile organic compound (VOC) and residual oil phase recovery are presented. The processes are illustrated by project examples.

Tuning the properties of polyhydroxybutyrate films using acetic acid via solvent casting

PubMed Central

Anbukarasu, Preetam; Sauvageau, Dominic; Elias, Anastasia

2015-01-01

Biodegradable polyhydroxybutyrate (PHB) films were fabricated using acetic acid as an alternative to common solvents such as chloroform. The PHB films were prepared using a solvent casting process at temperatures ranging from 80 °C to 160 °C. The crystallinity, mechanical properties and surface morphology of the films cast at different temperatures were characterized and compared to PHB films cast using chloroform as a solvent. Results revealed that the properties of the PHB film varied considerably with solvent casting temperature. In general, samples processed with acetic acid at low temperatures had comparable mechanical properties to PHB cast using chloroform. This acetic acid based method is environmentally friendly, cost efficient and allows more flexible processing conditions and broader ranges of polymer properties than traditional methods. PMID:26640089

Tuning the properties of polyhydroxybutyrate films using acetic acid via solvent casting

NASA Astrophysics Data System (ADS)

Anbukarasu, Preetam; Sauvageau, Dominic; Elias, Anastasia

2015-12-01

Biodegradable polyhydroxybutyrate (PHB) films were fabricated using acetic acid as an alternative to common solvents such as chloroform. The PHB films were prepared using a solvent casting process at temperatures ranging from 80 °C to 160 °C. The crystallinity, mechanical properties and surface morphology of the films cast at different temperatures were characterized and compared to PHB films cast using chloroform as a solvent. Results revealed that the properties of the PHB film varied considerably with solvent casting temperature. In general, samples processed with acetic acid at low temperatures had comparable mechanical properties to PHB cast using chloroform. This acetic acid based method is environmentally friendly, cost efficient and allows more flexible processing conditions and broader ranges of polymer properties than traditional methods.

Green nanoparticle production using micro reactor technology

NASA Astrophysics Data System (ADS)

Kück, A.; Steinfeldt, M.; Prenzel, K.; Swiderek, P.; Gleich, A. v.; Thöming, J.

2011-07-01

The importance and potential of nanoparticles in daily life as well as in various industrial processes is becoming more predominant. Specifically, silver nanoparticles are increasingly applied, e.g. in clothes and wipes, due to their antibacterial properties. For applications in liquid phase it is advantageous to produce the nanoparticles directly in suspension. This article describes a green production of silver nanoparticles using micro reactor technology considering principles of green chemistry. The aim is to reveal the potential and constraints of this approach and to show, how economic and environmental costs vary depending on process conditions. For this purpose our research compares the proposed process with water-based batch synthesis and demonstrates improvements in terms of product quality. Because of the lower energy consumption and lower demand of cleaning agents, micro reactor is the best ecological choice.

Optimization of process parameters for RF sputter deposition of tin-nitride thin-films

NASA Astrophysics Data System (ADS)

Jangid, Teena; Rao, G. Mohan

2018-05-01

Radio frequency Magnetron sputtering technique was employed to deposit Tin-nitride thin films on Si and glass substrate at different process parameters. Influence of varying parameters like substrate temperature, target-substrate distance and RF power is studied in detail. X-ray diffraction method is used as a key technique for analyzing the changes in the stoichiometric and structural properties of the deposited films. Depending on the combination of deposition parameters, crystalline as well as amorphous films were obtained. Pure tin-nitride thin films were deposited at 15W RF power and 600°C substrate temperature with target-substrate distance fixed at 10cm. Bandgap value of 1.6 eV calculated for the film deposited at optimum process conditions matches well with reported values.

Grain Boundary Engineering the Mechanical Properties of Allvac 718Plus(Trademark) Superalloy

NASA Technical Reports Server (NTRS)

Gabb, Timothy P.; Telesman, Jack; Garg, Anita; Lin, Peter; Provenzano, virgil; Heard, Robert; Miller, Herbert M.

2010-01-01

Grain Boundary Engineering can enhance the population of structurally-ordered "low S" Coincidence Site Lattice (CSL) grain boundaries in the microstructure. In some alloys, these "special" grain boundaries have been reported to improve overall resistance to corrosion, oxidation, and creep resistance. Such improvements could be quite beneficial for superalloys, especially in conditions which encourage damage and cracking at grain boundaries. Therefore, the effects of GBE processing on high-temperature mechanical properties of the cast and wrought superalloy Allvac 718Plus (Allvac ATI) were screened. Bar sections were subjected to varied GBE processing, and then consistently heat treated, machined, and tested at 650 C. Creep, tensile stress relaxation, and dwell fatigue crack growth tests were performed. The influences of GBE processing on microstructure, mechanical properties, and associated failure modes are discussed.

Analysis of a municipal wastewater treatment plant using a neural network-based pattern analysis

USGS Publications Warehouse

Hong, Y.-S.T.; Rosen, Michael R.; Bhamidimarri, R.

2003-01-01

This paper addresses the problem of how to capture the complex relationships that exist between process variables and to diagnose the dynamic behaviour of a municipal wastewater treatment plant (WTP). Due to the complex biological reaction mechanisms, the highly time-varying, and multivariable aspects of the real WTP, the diagnosis of the WTP are still difficult in practice. The application of intelligent techniques, which can analyse the multi-dimensional process data using a sophisticated visualisation technique, can be useful for analysing and diagnosing the activated-sludge WTP. In this paper, the Kohonen Self-Organising Feature Maps (KSOFM) neural network is applied to analyse the multi-dimensional process data, and to diagnose the inter-relationship of the process variables in a real activated-sludge WTP. By using component planes, some detailed local relationships between the process variables, e.g., responses of the process variables under different operating conditions, as well as the global information is discovered. The operating condition and the inter-relationship among the process variables in the WTP have been diagnosed and extracted by the information obtained from the clustering analysis of the maps. It is concluded that the KSOFM technique provides an effective analysing and diagnosing tool to understand the system behaviour and to extract knowledge contained in multi-dimensional data of a large-scale WTP. ?? 2003 Elsevier Science Ltd. All rights reserved.

Time-varying parameter models for catchments with land use change: the importance of model structure

NASA Astrophysics Data System (ADS)

Pathiraja, Sahani; Anghileri, Daniela; Burlando, Paolo; Sharma, Ashish; Marshall, Lucy; Moradkhani, Hamid

2018-05-01

Rapid population and economic growth in Southeast Asia has been accompanied by extensive land use change with consequent impacts on catchment hydrology. Modeling methodologies capable of handling changing land use conditions are therefore becoming ever more important and are receiving increasing attention from hydrologists. A recently developed data-assimilation-based framework that allows model parameters to vary through time in response to signals of change in observations is considered for a medium-sized catchment (2880 km2) in northern Vietnam experiencing substantial but gradual land cover change. We investigate the efficacy of the method as well as the importance of the chosen model structure in ensuring the success of a time-varying parameter method. The method was used with two lumped daily conceptual models (HBV and HyMOD) that gave good-quality streamflow predictions during pre-change conditions. Although both time-varying parameter models gave improved streamflow predictions under changed conditions compared to the time-invariant parameter model, persistent biases for low flows were apparent in the HyMOD case. It was found that HyMOD was not suited to representing the modified baseflow conditions, resulting in extreme and unrealistic time-varying parameter estimates. This work shows that the chosen model can be critical for ensuring the time-varying parameter framework successfully models streamflow under changing land cover conditions. It can also be used to determine whether land cover changes (and not just meteorological factors) contribute to the observed hydrologic changes in retrospective studies where the lack of a paired control catchment precludes such an assessment.

Visually induced gains in pitch discrimination: Linking audio-visual processing with auditory abilities.

PubMed

Møller, Cecilie; Højlund, Andreas; Bærentsen, Klaus B; Hansen, Niels Chr; Skewes, Joshua C; Vuust, Peter

2018-05-01

Perception is fundamentally a multisensory experience. The principle of inverse effectiveness (PoIE) states how the multisensory gain is maximal when responses to the unisensory constituents of the stimuli are weak. It is one of the basic principles underlying multisensory processing of spatiotemporally corresponding crossmodal stimuli that are well established at behavioral as well as neural levels. It is not yet clear, however, how modality-specific stimulus features influence discrimination of subtle changes in a crossmodally corresponding feature belonging to another modality. Here, we tested the hypothesis that reliance on visual cues to pitch discrimination follow the PoIE at the interindividual level (i.e., varies with varying levels of auditory-only pitch discrimination abilities). Using an oddball pitch discrimination task, we measured the effect of varying visually perceived vertical position in participants exhibiting a wide range of pitch discrimination abilities (i.e., musicians and nonmusicians). Visual cues significantly enhanced pitch discrimination as measured by the sensitivity index d', and more so in the crossmodally congruent than incongruent condition. The magnitude of gain caused by compatible visual cues was associated with individual pitch discrimination thresholds, as predicted by the PoIE. This was not the case for the magnitude of the congruence effect, which was unrelated to individual pitch discrimination thresholds, indicating that the pitch-height association is robust to variations in auditory skills. Our findings shed light on individual differences in multisensory processing by suggesting that relevant multisensory information that crucially aids some perceivers' performance may be of less importance to others, depending on their unisensory abilities.

Study of the Evolution of the Electric Structure of a Convective Cloud Using the Data of a Numerical Nonstationary Three-Dimensional Model

NASA Astrophysics Data System (ADS)

Veremey, N. E.; Dovgalyuk, Yu. A.; Zatevakhin, M. A.; Ignatyev, A. A.; Morozov, V. N.

2014-04-01

Numerical nonstationary three-dimensional model of a convective cloud with parameterized description of microphysical processes with allowance for the electrization processes is considered. The results of numerical modeling of the cloud evolution for the specified atmospheric conditions are presented. The spatio-temporal distribution of the main cloud characteristics including the volume charge density and the electric field is obtained. The calculation results show that the electric structure of the cloud is different at its various life stages, i.e., it varies from unipolar to dipolar and then to tripolar. This conclusion is in fair agreement with the field studies.

California residential energy standards: problems and recommendations relating to implementation, enforcement, and design. [Thermal insulation

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

Not Available

1977-08-01

Documents relevant to the development and implementation of the California energy insulation standards for new residential buildings were evaluated and a survey was conducted to determine problems encountered in the implementation, enforcement, and design aspects of the standards. The impact of the standards on enforcement agencies, designers, builders and developers, manufacturers and suppliers, consumers, and the building process in general is summarized. The impact on construction costs and energy savings varies considerably because of the wide variation in prior insulation practices and climatic conditions in California. The report concludes with a series of recommendations covering all levels of government andmore » the building process. (MCW)« less

Effect of Weld Tool Geometry on Friction Stir Welded AA2219-T87 Properties

NASA Technical Reports Server (NTRS)

Querin, Joseph A.; Schneider, Judy A.

2008-01-01

In this study, flat panels of AA2219-T87 were friction stir welded (FSWed) using weld tools with tapered pins The three pin geometries of the weld tools included: 0 (straight cylinder), 30 , and 60 angles on the frustum. For each weld tool geometry, the FSW process parameters were optimized to eliminate defects. A constant heat input was maintained while varying the process parameters of spindle rpm and travel speed. This provided a constant heat input for each FSW weld panel while altering the hot working conditions imparted to the workpiece. The resulting mechanical properties were evaluated from tensile test results of the FSW joint.

Development of a System Model for Non-Invasive Quantification of Bilirubin in Jaundice Patients

NASA Astrophysics Data System (ADS)

Alla, Suresh K.

Neonatal jaundice is a medical condition which occurs in newborns as a result of an imbalance between the production and elimination of bilirubin. Excess bilirubin in the blood stream diffuses into the surrounding tissue leading to a yellowing of the skin. An optical system integrated with a signal processing system is used as a platform to noninvasively quantify bilirubin concentration through the measurement of diffuse skin reflectance. Initial studies have lead to the generation of a clinical analytical model for neonatal jaundice which generates spectral reflectance data for jaundiced skin with varying levels of bilirubin concentration in the tissue. The spectral database built using the clinical analytical model is then used as a test database to validate the signal processing system in real time. This evaluation forms the basis for understanding the translation of this research to human trials. The clinical analytical model and signal processing system have been successful validated on three spectral databases. First spectral database is constructed using a porcine model as a surrogate for neonatal skin tissue. Samples of pig skin were soaked in bilirubin solutions of varying concentrations to simulate jaundice skin conditions. The resulting skins samples were analyzed with our skin reflectance systems producing bilirubin concentration values that show a high correlation (R2 = 0.94) to concentration of the bilirubin solution that each porcine tissue sample is soaked in. The second spectral database is the spectral measurements collected on human volunteers to quantify the different chromophores and other physical properties of the tissue such a Hematocrit, Hemoglobin etc. The third spectral database is the spectral data collected at different time periods from the moment a bruise is induced.

Modeling diffusion in foamed polymer nanocomposites.

PubMed

Ippalapalli, Sandeep; Ranaprathapan, A Dileep; Singh, Sachchida N; Harikrishnan, G

2013-04-15

Two-way multicomponent diffusion processes in polymeric nanocomposite foams, where the condensed phase is nanoscopically reinforced with impermeable fillers, are investigated. The diffusion process involves simultaneous outward permeation of the components of the dispersed gas phase and inward diffusion of atmospheric air. The transient variation in thermal conductivity of foam is used as the macroscopic property to track the compositional variations of the dispersed gases due to the diffusion process. In the continuum approach adopted, the unsteady-state diffusion process is combined with tortuosity theory. The simulations conducted at ambient temperature reveal distinct regimes of diffusion processes in the nanocomposite foams owing to the reduction in the gas-transport rate induced by nanofillers. Simulations at a higher temperature are also conducted and the predictions are compared with experimentally determined thermal conductivities under accelerated diffusion conditions for polyurethane foams reinforced with clay nanoplatelets of varying individual lamellar dimensions. Intermittent measurements of foam thermal conductivity are performed while the accelerated diffusion proceeded. The predictions under accelerated diffusion conditions show good agreement with experimentally measured thermal conductivities for nanocomposite foams reinforced with low and medium aspect-ratios fillers. The model shows higher deviations for foams with fillers that have a high aspect ratio. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Final technical report. In-situ FT-IR monitoring of a black liquor recovery boiler

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

James Markham; Joseph Cosgrove; David Marran

1999-05-31

This project developed and tested advanced Fourier transform infrared (FT-IR) instruments for process monitoring of black liquor recovery boilers. The state-of-the-art FT-IR instruments successfully operated in the harsh environment of a black liquor recovery boiler and provided a wealth of real-time process information. Concentrations of multiple gas species were simultaneously monitored in-situ across the combustion flow of the boiler and extractively at the stack. Sensitivity to changes of particulate fume and carryover levels in the process flow were also demonstrated. Boiler set-up and operation is a complex balance of conditions that influence the chemical and physical processes in the combustionmore » flow. Operating parameters include black liquor flow rate, liquor temperature, nozzle pressure, primary air, secondary air, tertiary air, boiler excess oxygen and others. The in-process information provided by the FT-IR monitors can be used as a boiler control tool since species indicative of combustion efficiency (carbon monoxide, methane) and pollutant emissions (sulfur dioxide, hydrochloric acid and fume) were monitored in real-time and observed to fluctuate as operating conditions were varied. A high priority need of the U.S. industrial boiler market is improved measurement and control technology. The sensor technology demonstrated in this project is applicable to the need of industry.« less

Study of the Ohmic Contact Mechanism of Oxidized Ni/Au Contact to p-GaN

NASA Astrophysics Data System (ADS)

Roesler, Erika; Chengyu, Hu; Zhang, Guoyi

2004-03-01

In the semiconductor industry, GaN is important for blue Laser Diodes (LDs) and Light Emitting Diodes (LEDs). In order to maximize efficiency for optoelectronic devices that utilize GaN products, a low contact resistance and an ohmic contact are needed. Previously, the contact resistance has been found to be as low as 10-4 Ohms cm^2. The aim of this research project was to investigate the influence of different annealing conditions for the contact resistance; analyze the microstructure of the electrodes; find the relationship between the microstructure, annealing conditions, and contact resistance; and then explain the mechanism. The sample was grown in a MOCVD system and had a mesa structure. It was activated with Mg-H 800 C for 20 minutes to become a p-type GaN semiconductor. The sample underwent four different annealing conditions. The first condition varied the temperature in constant Oxygen ambient; the second varied the temperature in air; the third varied the percentage of Oxygen with Nitrogen in constant temperature; and the fourth varied the time annealed under Oxygen ambient. The third condition has never previously been tested. We found definite minimums of the contact resistivity (using the TLM method) in the first condition and second conditions at 500 C. The third condition had the best results with a mix of 50% Oxygen and 50the fourth condition had the best results at 5 minutes. Once the effects of the microstructure are analyzed for the sample at each condition, a better understanding of the physical mechanisms to yield the contact resistance will be known.

Simulation of disturbance rejection control of half-car active suspension system using active disturbance rejection control with decoupling transformation

NASA Astrophysics Data System (ADS)

Hasbullah, Faried; Faris, Waleed F.

2017-12-01

In recent years, Active Disturbance Rejection Control (ADRC) has become a popular control alternative due to its easy applicability and robustness to varying processes. In this article, ADRC with input decoupling transformation (ADRC-IDT) is proposed to improve ride comfort of a vehicle with an active suspension system using half-car model. The ride performance of the ADRC-IDT is evaluated and compared with decentralized ADRC control as well as the passive system. Simulation results show that both ADRC and ADRC-IDT manage to appreciably reduce body accelerations and able to cope well with varying conditions typically encountered in an active suspension system. Also, it is sufficient to control only the body motions with both active controllers to improve ride comfort while maintaining good road holding and small suspension working space.

Convergent Time-Varying Regression Models for Data Streams: Tracking Concept Drift by the Recursive Parzen-Based Generalized Regression Neural Networks.

PubMed

Duda, Piotr; Jaworski, Maciej; Rutkowski, Leszek

2018-03-01

One of the greatest challenges in data mining is related to processing and analysis of massive data streams. Contrary to traditional static data mining problems, data streams require that each element is processed only once, the amount of allocated memory is constant and the models incorporate changes of investigated streams. A vast majority of available methods have been developed for data stream classification and only a few of them attempted to solve regression problems, using various heuristic approaches. In this paper, we develop mathematically justified regression models working in a time-varying environment. More specifically, we study incremental versions of generalized regression neural networks, called IGRNNs, and we prove their tracking properties - weak (in probability) and strong (with probability one) convergence assuming various concept drift scenarios. First, we present the IGRNNs, based on the Parzen kernels, for modeling stationary systems under nonstationary noise. Next, we extend our approach to modeling time-varying systems under nonstationary noise. We present several types of concept drifts to be handled by our approach in such a way that weak and strong convergence holds under certain conditions. Finally, in the series of simulations, we compare our method with commonly used heuristic approaches, based on forgetting mechanism or sliding windows, to deal with concept drift. Finally, we apply our concept in a real life scenario solving the problem of currency exchange rates prediction.

Incineration of tannery sludge under oxic and anoxic conditions: study of chromium speciation.

PubMed

Kavouras, P; Pantazopoulou, E; Varitis, S; Vourlias, G; Chrissafis, K; Dimitrakopulos, G P; Mitrakas, M; Zouboulis, A I; Karakostas, Th; Xenidis, A

2015-01-01

A tannery sludge, produced from physico-chemical treatment of tannery wastewaters, was incinerated without any pre-treatment process under oxic and anoxic conditions, by controlling the abundance of oxygen. Incineration in oxic conditions was performed at the temperature range from 300°C to 1200°C for duration of 2h, while in anoxic conditions at the temperature range from 400°C to 600°C and varying durations. Incineration under oxic conditions at 500°C resulted in almost total oxidation of Cr(III) to Cr(VI), with CaCrO4 to be the crystalline phase containing Cr(VI). At higher temperatures a part of Cr(VI) was reduced, mainly due to the formation of MgCr2O4. At 1200°C approximately 30% of Cr(VI) was reduced to Cr(III). Incineration under anoxic conditions substantially reduced the extent of oxidation of Cr(III) to Cr(VI). Increase of temperature and duration of incineration lead to increase of Cr(VI) content, while no chromium containing crystalline phase was detected. Copyright © 2014 Elsevier B.V. All rights reserved.

The Effects of Varying Contextual Demands on Age-related Positive Gaze Preferences

PubMed Central

Noh, Soo Rim; Isaacowitz, Derek M.

2015-01-01

Despite many studies on the age-related positivity effect and its role in visual attention, discrepancies remain regarding whether one’s full attention is required for age-related differences to emerge. The present study took a new approach to this question by varying the contextual demands of emotion processing. This was done by adding perceptual distractions, such as visual and auditory noise, that could disrupt attentional control. Younger and older participants viewed pairs of happy–neutral and fearful–neutral faces while their eye movements were recorded. Facial stimuli were shown either without noise, embedded in a background of visual noise (low, medium, or high), or with simultaneous auditory babble. Older adults showed positive gaze preferences, looking toward happy faces and away from fearful faces; however, their gaze preferences tended to be influenced by the level of visual noise. Specifically, the tendency to look away from fearful faces was not present in conditions with low and medium levels of visual noise, but was present where there were high levels of visual noise. It is important to note, however, that in the high-visual-noise condition, external cues were present to facilitate the processing of emotional information. In addition, older adults’ positive gaze preferences disappeared or were reduced when they first viewed emotional faces within a distracting context. The current results indicate that positive gaze preferences may be less likely to occur in distracting contexts that disrupt control of visual attention. PMID:26030774

The effects of varying contextual demands on age-related positive gaze preferences.

PubMed

Noh, Soo Rim; Isaacowitz, Derek M

2015-06-01

Despite many studies on the age-related positivity effect and its role in visual attention, discrepancies remain regarding whether full attention is required for age-related differences to emerge. The present study took a new approach to this question by varying the contextual demands of emotion processing. This was done by adding perceptual distractions, such as visual and auditory noise, that could disrupt attentional control. Younger and older participants viewed pairs of happy-neutral and fearful-neutral faces while their eye movements were recorded. Facial stimuli were shown either without noise, embedded in a background of visual noise (low, medium, or high), or with simultaneous auditory babble. Older adults showed positive gaze preferences, looking toward happy faces and away from fearful faces; however, their gaze preferences tended to be influenced by the level of visual noise. Specifically, the tendency to look away from fearful faces was not present in conditions with low and medium levels of visual noise but was present when there were high levels of visual noise. It is important to note, however, that in the high-visual-noise condition, external cues were present to facilitate the processing of emotional information. In addition, older adults' positive gaze preferences disappeared or were reduced when they first viewed emotional faces within a distracting context. The current results indicate that positive gaze preferences may be less likely to occur in distracting contexts that disrupt control of visual attention. (c) 2015 APA, all rights reserved.

Node-based measures of connectivity in genetic networks.

PubMed

Koen, Erin L; Bowman, Jeff; Wilson, Paul J

2016-01-01

At-site environmental conditions can have strong influences on genetic connectivity, and in particular on the immigration and settlement phases of dispersal. However, at-site processes are rarely explored in landscape genetic analyses. Networks can facilitate the study of at-site processes, where network nodes are used to model site-level effects. We used simulated genetic networks to compare and contrast the performance of 7 node-based (as opposed to edge-based) genetic connectivity metrics. We simulated increasing node connectivity by varying migration in two ways: we increased the number of migrants moving between a focal node and a set number of recipient nodes, and we increased the number of recipient nodes receiving a set number of migrants. We found that two metrics in particular, the average edge weight and the average inverse edge weight, varied linearly with simulated connectivity. Conversely, node degree was not a good measure of connectivity. We demonstrated the use of average inverse edge weight to describe the influence of at-site habitat characteristics on genetic connectivity of 653 American martens (Martes americana) in Ontario, Canada. We found that highly connected nodes had high habitat quality for marten (deep snow and high proportions of coniferous and mature forest) and were farther from the range edge. We recommend the use of node-based genetic connectivity metrics, in particular, average edge weight or average inverse edge weight, to model the influences of at-site habitat conditions on the immigration and settlement phases of dispersal. © 2015 John Wiley & Sons Ltd.

A Comparative Data-Based Modeling Study on Respiratory CO2 Gas Exchange during Mechanical Ventilation

PubMed Central

Kim, Chang-Sei; Ansermino, J. Mark; Hahn, Jin-Oh

2016-01-01

The goal of this study is to derive a minimally complex but credible model of respiratory CO2 gas exchange that may be used in systematic design and pilot testing of closed-loop end-tidal CO2 controllers in mechanical ventilation. We first derived a candidate model that captures the essential mechanisms involved in the respiratory CO2 gas exchange process. Then, we simplified the candidate model to derive two lower-order candidate models. We compared these candidate models for predictive capability and reliability using experimental data collected from 25 pediatric subjects undergoing dynamically varying mechanical ventilation during surgical procedures. A two-compartment model equipped with transport delay to account for CO2 delivery between the lungs and the tissues showed modest but statistically significant improvement in predictive capability over the same model without transport delay. Aggregating the lungs and the tissues into a single compartment further degraded the predictive fidelity of the model. In addition, the model equipped with transport delay demonstrated superior reliability to the one without transport delay. Further, the respiratory parameters derived from the model equipped with transport delay, but not the one without transport delay, were physiologically plausible. The results suggest that gas transport between the lungs and the tissues must be taken into account to accurately reproduce the respiratory CO2 gas exchange process under conditions of wide-ranging and dynamically varying mechanical ventilation conditions. PMID:26870728

On the nature of extraversion: variation in conditioned contextual activation of dopamine-facilitated affective, cognitive, and motor processes

PubMed Central

Depue, Richard A.; Fu, Yu

2013-01-01

Research supports an association between extraversion and dopamine (DA) functioning. DA facilitates incentive motivation and the conditioning and incentive encoding of contexts that predict reward. Therefore, we assessed whether extraversion is related to the efficacy of acquiring conditioned contextual facilitation of three processes that are dependent on DA: motor velocity, positive affect, and visuospatial working memory. We exposed high and low extraverts to three days of association of drug reward (methylphenidate, MP) with a particular laboratory context (Paired group), a test day of conditioning, and three days of extinction in the same laboratory. A Placebo group and an Unpaired group (that had MP in a different laboratory context) served as controls. Conditioned contextual facilitation was assessed by (i) presenting video clips that varied in their pairing with drug and laboratory context and in inherent incentive value, and (ii) measuring increases from day 1 to Test day on the three processes above. Results showed acquisition of conditioned contextual facilitation across all measures to video clips that had been paired with drug and laboratory context in the Paired high extraverts, but no conditioning in the Paired low extraverts (nor in either of the control groups). Increases in the Paired high extraverts were correlated across the three measures. Also, conditioned facilitation was evident on the first day of extinction in Paired high extraverts, despite the absence of the unconditioned effects of MP. By the last day of extinction, responding returned to day 1 levels. The findings suggest that extraversion is associated with variation in the acquisition of contexts that predict reward. Over time, this variation may lead to differences in the breadth of networks of conditioned contexts. Thus, individual differences in extraversion may be maintained by activation of differentially encoded central representations of incentive contexts that predict reward. PMID:23785330

Effect of plasma spray processing variations on particle melting and splat spreading of hydroxylapatite and alumina

NASA Astrophysics Data System (ADS)

Yankee, S. J.; Pletka, B. J.

1993-09-01

Splats of hydroxylapatite (HA) and alumina were obtained via plasma spraying using systematically varied combinations of plasma velocity and temperature, which were achieved by altering the primary plasma gas flow rate and plasma gas composition. Particle size was also varied in the case of alumina. Splat spreading was quantified via computer- aided image analysis as a function of processing variations. A comparison of the predicted splat dimensions from a model developed by Madejski with experimental observations of HA and alumina splats was performed. The model tended to underestimate the HA splat sizes, suggesting that evaporation of smaller particles occurred under the chosen experimental conditions, and to overestimate the observed alumina splat dimensions. Based on this latter result and on the surface appearance of the substrates, incomplete melting appeared to take place in all but the smaller alumina particles. Analysis of the spreading data as a function of the processing variations indicated that the particle size as well as the plasma temperature and velocity influenced the extent of particle melting. Based on these data and other considerations, a physical model was developed that described the degree of particle melting in terms of material and processing parameters. The physical model correctly predicted the relative splat spreading behavior of HA and alumina, assuming that spreading was directly linked to the extent of particle melting.

Processing effects in production of composite prepreg by hot melt impregnation

NASA Astrophysics Data System (ADS)

Chmielewski, C.; Jayaraman, K.; Petty, C. A.

1993-06-01

The hot melt impregnation process for producing composite prepreg has been studied. The role of the exit die is highlighted by operating without impregnation bars. Experimental results show that when a fiber tow is pulled through a resin bath and then through a wedge shaped die, the total resin mass fraction and the extent of resin impregnation in the tow increase with the processing viscosity. The penetration of resin into a fiber bundle is greater when the resin viscosity is higher. This trend is unchanged over a range of tow speeds up to the breaking point. A theoretical model is developed to describe the effect of processing conditions and die geometry on the degree of impregnation. Calculations with this model indicate that for a given die geometry, the degree of impregnation increases from 58 percent to 90 percent as the ratio of the clearance between the tow and the die wall, to the total die gap is decreased from 0.15 to 0.05. Physical arguments related to the effective viscosity of the prepreg show that the clearance ratio is independent of the tow speed, but decreases as the ratio of the effective shear viscosity of the prepreg to the resin viscosity increases. This provides a connection between the experimental results obtained with varying resin viscosity and the computational results obtained with varying clearance values at the die inlet.

Phenotypic plasticity to light and nutrient availability alters functional trait ranking across eight perennial grassland species.

PubMed

Siebenkäs, Alrun; Schumacher, Jens; Roscher, Christiane

2015-03-27

Functional traits are often used as species-specific mean trait values in comparative plant ecology or trait-based predictions of ecosystem processes, assuming that interspecific differences are greater than intraspecific trait variation and that trait-based ranking of species is consistent across environments. Although this assumption is increasingly challenged, there is a lack of knowledge regarding to what degree the extent of intraspecific trait variation in response to varying environmental conditions depends on the considered traits and the characteristics of the studied species to evaluate the consequences for trait-based species ranking. We studied functional traits of eight perennial grassland species classified into different functional groups (forbs vs. grasses) and varying in their inherent growth stature (tall vs. small) in a common garden experiment with different environments crossing three levels of nutrient availability and three levels of light availability over 4 months of treatment applications. Grasses and forbs differed in almost all above- and belowground traits, while trait differences related to growth stature were generally small. The traits showing the strongest responses to resource availability were similarly for grasses and forbs those associated with allocation and resource uptake. The strength of trait variation in response to varying resource availability differed among functional groups (grasses > forbs) and species of varying growth stature (small-statured > tall-statured species) in many aboveground traits, but only to a lower extent in belowground traits. These differential responses altered trait-based species ranking in many aboveground traits, such as specific leaf area, tissue nitrogen and carbon concentrations and above-belowground allocation (leaf area ratio and root : shoot ratio) at varying resource supply, while trait-based species ranking was more consistent in belowground traits. Our study shows that species grouping according to functional traits is valid, but trait-based species ranking depends on environmental conditions, thus limiting the applicability of species-specific mean trait values in ecological studies. Published by Oxford University Press on behalf of the Annals of Botany Company.

Impact of (α, n) reactions on weak r-process in neutrino-driven winds

NASA Astrophysics Data System (ADS)

Bliss, J.; Arcones, A.; Montes, F.; Pereira, J.

2017-05-01

After a successful core-collapse supernova, a neutrino-driven wind develops where it is possible to synthesize lighter heavy elements (30 < Z < 45). In the early galaxy, the origin of these elements is associated with the r-process and to an additional process. Here we assume that the additional process corresponds to the weak r-process (sometimes referred to as alpha-process) taking place in neutrino-driven winds. Based on a trajectory obtained from hydrodynamical simulations we study the astrophysics and nuclear physics uncertainties of a weak r-process with our main focus on the (α, n) reactions. These reactions are critical to redistribute the matter and allow it to move from light to heavy elements after nuclear statistical equilibrium freezes out. In this first sensitivity study, we vary all (α, n) reactions by given constant factors which are justified based on the uncertainties of the statistical model and its nuclear physics input, mainly alpha optical potentials for weak r-process conditions. Our results show that (α, n) rate uncertainties are indeed crucial to predict abundances. Therefore, further studies will follow to identify individual critical reactions. Since the nucleosynthesis path is close to stability, these reactions can be measured in the near future. Since much of the other nuclear data for the weak r-process are known, the reduction in nuclear physics uncertainties provided by these experiments will allow astronomical observations to directly constrain the astronomical conditions in the wind.

Retrieving self-vocalized information: An event-related potential (ERP) study on the effect of retrieval orientation.

PubMed

Rosburg, Timm; Johansson, Mikael; Sprondel, Volker; Mecklinger, Axel

2014-11-18

Retrieval orientation refers to a pre-retrieval process and conceptualizes the specific form of processing that is applied to a retrieval cue. In the current event-related potential (ERP) study, we sought to find evidence for an involvement of the auditory cortex when subjects attempt to retrieve vocalized information, and hypothesized that adopting retrieval orientation would be beneficial for retrieval accuracy. During study, participants saw object words that they subsequently vocalized or visually imagined. At test, participants had to identify object names of one study condition as targets and to reject object names of the second condition together with new items. Target category switched after half of the test trials. Behaviorally, participants responded less accurately and more slowly to targets of the vocalize condition than to targets of the imagine condition. ERPs to new items varied at a single left electrode (T7) between 500 and 800ms, indicating a moderate retrieval orientation effect in the subject group as a whole. However, whereas the effect was strongly pronounced in participants with high retrieval accuracy, it was absent in participants with low retrieval accuracy. A current source density (CSD) mapping of the retrieval orientation effect indicated a source over left temporal regions. Independently from retrieval accuracy, the ERP retrieval orientation effect was surprisingly also modulated by test order. Findings are suggestive for an involvement of the auditory cortex in retrieval attempts of vocalized information and confirm that adopting retrieval orientation is potentially beneficial for retrieval accuracy. The effects of test order on retrieval-related processes might reflect a stronger focus on the newness of items in the more difficult test condition when participants started with this condition. Copyright © 2014 Elsevier Inc. All rights reserved.

Storage of RF photons in minimal conditions

NASA Astrophysics Data System (ADS)

Cromières, J.-P.; Chanelière, T.

2018-02-01

We investigate the minimal conditions to store coherently a RF pulse in a material medium. We choose a commercial quartz as a memory support because it is a widely available component with a high Q-factor. Pulse storage is obtained by varying dynamically the light-matter coupling with an analog switch. This parametric driving of the quartz dynamics can be alternatively interpreted as a stopped-light experiment. We obtain an efficiency of 26%, a storage time of 209 μs and a time-to-bandwidth product of 98 by optimizing the pulse temporal shape. The coherent character of the storage is demonstrated. Our goal is to connect different types of memories in the RF and optical domain for quantum information processing. Our motivation is essentially fundamental.

A common presentation to an uncommon disease. Penile Mondor's disease: a case report and literature review.

PubMed

Walsh, John C; Poimboeuf, Sabré; Garvin, Daniel S

2014-01-01

Penile Mondor's disease, or superficial thrombophlebitis of the dorsal vein of the penis, is a relatively uncommon but potentially anxiety-inducing self-limiting condition that should be easily recognizable by any primary care practitioner. It typically presents with a cord-like mass and pain to the dorsal penis and has a myriad of causes, including trauma, excessive sexual activity, excessive exercise, or malignancy. Although Penile Mondor's disease is typically a clinical diagnosis, Doppler ultrasound is the initial imaging modality of choice if there is question or doubt about the diagnosis. Accurate diagnosis and reassurance about the condition's benign and self-limiting nature assuages most patients' fears. Treatment is primarily symptomatic but may vary depending on possible underlying disease processes.

Rolling element bearing defect diagnosis under variable speed operation through angle synchronous averaging of wavelet de-noised estimate

NASA Astrophysics Data System (ADS)

Mishra, C.; Samantaray, A. K.; Chakraborty, G.

2016-05-01

Rolling element bearings are widely used in rotating machines and their faults can lead to excessive vibration levels and/or complete seizure of the machine. Under special operating conditions such as non-uniform or low speed shaft rotation, the available fault diagnosis methods cannot be applied for bearing fault diagnosis with full confidence. Fault symptoms in such operating conditions cannot be easily extracted through usual measurement and signal processing techniques. A typical example is a bearing in heavy rolling mill with variable load and disturbance from other sources. In extremely slow speed operation, variation in speed due to speed controller transients or external disturbances (e.g., varying load) can be relatively high. To account for speed variation, instantaneous angular position instead of time is used as the base variable of signals for signal processing purposes. Even with time synchronous averaging (TSA) and well-established methods like envelope order analysis, rolling element faults in rolling element bearings cannot be easily identified during such operating conditions. In this article we propose to use order tracking on the envelope of the wavelet de-noised estimate of the short-duration angle synchronous averaged signal to diagnose faults in rolling element bearing operating under the stated special conditions. The proposed four-stage sequential signal processing method eliminates uncorrelated content, avoids signal smearing and exposes only the fault frequencies and its harmonics in the spectrum. We use experimental data1

Neural correlates of deception in social contexts in normally developing children

PubMed Central

Yokota, Susumu; Taki, Yasuyuki; Hashizume, Hiroshi; Sassa, Yuko; Thyreau, Benjamin; Tanaka, Mari; Kawashima, Ryuta

2013-01-01

Deception is related to the ability to inhibit prepotent responses and to engage in mental tasks such as anticipating responses and inferring what another person knows, especially in social contexts. However, the neural correlates of deception processing, which requires mentalizing, remain unclear. Using functional magnetic resonance imaging (fMRI), we examined the neural correlates of deception, including mentalization, in social contexts in normally developing children. Healthy right-handed children (aged 8–9 years) were scanned while performing interactive games involving deception. The games varied along two dimensions: the type of reply (deception and truth) and the type of context (social and less social). Participants were instructed to deceive a witch and to tell the truth to a girl. Under the social-context conditions, participants were asked to consider what they inferred about protagonists' preferences from their facial expressions when responding to questions. Under the less-social-context conditions, participants did not need to consider others' preferences. We found a significantly greater response in the right precuneus under the social-context than under less-social-context conditions. Additionally, we found marginally greater activation in the right inferior parietal lobule (IPL) under the deception than under the truth condition. These results suggest that deception in a social context requires not only inhibition of prepotent responses but also engagement in mentalizing processes. This study provides the first evidence of the neural correlates of the mentalizing processes involved in deception in normally developing children. PMID:23730281

The secretion of alkali metal ions by the perfused cat pancreas as influenced by the composition and osmolality of the external environment and by inhibitors of metabolism and Na+, K+-ATPase activity

PubMed Central

Case, R. M.; Scratcherd, T.

1974-01-01

1. The secretion of sodium, potassium and lithium has been studied in the isolated cat pancreas, perfused with bicarbonate buffered saline solutions of varying composition and osmolality, and stimulated maximally with secretin. 2. Under isosmolal conditions, when perfusate sodium chloride was replaced by sucrose, sodium secretion and potassium secretion were directly related to perfusate sodium concentration, [Na]p. 3. When osmolality was varied by increasing or decreasing perfusate sodium chloride concentration, the secretion of sodium and of potassium were maximal at [Na]p of about 120 and 80 mM respectively. 4. At a given [Na]p, sodium secretion was greater under hypo-osmolal conditions than under isosmolal conditions. 5. When potassium concentration was varied over the range 0-130 mM under isosmolal conditions, by adjusting perfusate NaCl concentration, the secretion of potassium and of sodium were maximal at [K]p of about 50 and 10 mM respectively. Water flux was maximal at a [K]p of 10-15 mM. The concentration of potassium in the secretion was almost identical with that in the perfusate over the whole concentration range. 6. Replacement of perfusate sodium by lithium reduced the volume of secretion, though a small secretion was maintained even in the complete absence of sodium. The concentration of lithium in the secretion was generally slightly greater than that in the perfusate. 7. Omission of potassium from the perfusate reduced secretion by about 65%. Rubidium was a complete substitute for potassium; caesium was not. 8. Energy for secretion is derived largely from oxidative phosphorylation. Secretion was reduced by more than 90% under anaerobic conditions and in the presence of dinitrophenol or cyanide. Removal of glucose from the perfusate reduced secretion by more than 50% within 30 min; lactate was a complete substitute for glucose. 9. Ouabain, ethacrinic acid and frusimide, known inhibitors of Na+, K+-ATPase activity, all inhibited pancreatic electrolyte secretion. 10. The observations are interpreted with reference to the nature of active transport processes involved in pancreatic electrolyte secretion. PMID:4281836

Odour emissions from poultry litter - A review litter properties, odour formation and odorant emissions from porous materials.

PubMed

Dunlop, Mark W; Blackall, Patrick J; Stuetz, Richard M

2016-07-15

Odour emissions from meat chicken sheds can at times cause odour impacts on surrounding communities. Litter is seen as the primary source of this odour. Formation and emission of odour from meat chicken litter during the grow-out period are influenced by various factors such as litter conditions, the environment, microbial activity, properties of the odorous gases and management practices. Odour emissions vary spatially and temporally. This variability has made it challenging to understand how specific litter conditions contribute to odour emissions from the litter and production sheds. Existing knowledge on odorants, odour formation mechanisms and emission processes that contribute to odour emissions from litter are reviewed. Litter moisture content and water thermodynamics (i.e. water activity, Aw) are also examined as factors that contribute to microbial odour formation, physical litter conditions and the exchange of individual odorant gases at the air-water interface. Substantial opportunities exist for future research on litter conditions and litter formation mechanisms and how these contribute to odour emissions. Closing this knowledge gap will improve management strategies that intercept and interfere with odour formation and emission processes leading to an overall reduction in the potential to cause community impacts. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Phenotypic evaluation and characterization of 21 industrial Saccharomyces cerevisiae yeast strains.

PubMed

Kong, In Iok; Turner, Timothy Lee; Kim, Heejin; Kim, Soo Rin; Jin, Yong-Su

2018-02-01

Microorganisms have been studied and used extensively to produce value-added fuels and chemicals. Yeasts, specifically Saccharomyces cerevisiae, receive industrial attention because of their well-known ability to ferment glucose and produce ethanol. Thousands of natural or genetically modified S. cerevisiae have been found in industrial environments for various purposes. These industrial strains are isolated from industrial fermentation sites, and they are considered as potential host strains for superior fermentation processes. In many cases, industrial yeast strains have higher thermotolerance, increased resistances towards fermentation inhibitors and increased glucose fermentation rates under anaerobic conditions when compared with laboratory yeast strains. Despite the advantages of industrial strains, they are often not well characterized. Through screening and phenotypic characterization of commercially available industrial yeast strains, industrial fermentation processes requiring specific environmental conditions may be able to select an ideal starting yeast strain to be further engineered. Here, we have characterized and compared 21 industrial S. cerevisiae strains under multiple conditions, including their tolerance to varying pH conditions, resistance to fermentation inhibitors, sporulation efficiency and ability to ferment lignocellulosic sugars. These data may be useful for the selection of a parental strain for specific biotechnological applications of engineered yeast. © FEMS 2018. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Pitting and Stress Corrosion Cracking Susceptibility of Nanostructured Al-Mg Alloys in Natural and Artificial Environments

NASA Astrophysics Data System (ADS)

Sharma, Mala M.; Ziemian, Constance W.

2008-12-01

The stress corrosion cracking (SCC) behavior of two developmental nanocrystalline 5083 alloys with varied composition and processing conditions was studied. The results were compared to a commercial aluminum AA 5083 (H111) alloy. The pitting densities, size and depths, and residual tensile strengths were measured after alternate immersion in artificial seawater and atmospheric exposure under different loading conditions. Optical and scanning electron microscopy (SEM) with EDX was used to analyze the fracture surfaces of failed specimen after removal at selected intervals and tensile testing. One of the nanostructured Al-Mg alloys exhibited significantly superior pitting resistance when compared to conventional microstructured AA 5083. Under conditions where pitting corrosion showed up as local tunnels toward phase inclusions, transgranular cracking was observed, whereas under conditions when pitting corrosion evolved along grain boundaries, intergranular cracking inside the pit was observed. Pit initiation resistance of the nano alloys appears to be better than that of the conventional alloys. However, long-term pit propagation is a concern and warrants further study. The objective of this investigation was to obtain information regarding the role that ultra-fine microstructures play in their degradation in marine environments and to provide insight into the corrosion mechanisms and damage processes of these alloys.

Dopamine treatment and cognitive functioning in individuals with Parkinson's disease: the "cognitive flexibility" hypothesis seems to work.

PubMed

Costa, Alberto; Peppe, Antonella; Mazzù, Ilenia; Longarzo, Mariachiara; Caltagirone, Carlo; Carlesimo, Giovanni A

2014-01-01

Previous data suggest that (i) dopamine modulates the ability to implement nonroutine schemata and update operations (flexibility processes) and that (ii) dopamine-related improvement may be related to baseline dopamine levels in target pathways (inverted U-shaped hypothesis). To investigate above hypotheses in individuals with Parkinson's disease (PD). Twenty PD patients were administered tasks varying as to flexibility load in two treatment conditions: (i) "off" condition, about 18 hours after dopamine dose and (ii) "on" condition, after dopamine administration. PD patients were separated into two groups: low performers (i.e., performance on Digit Span Backward below the sample mean) and high performers (i.e., performance above the mean). Twenty healthy individuals performed the tasks in two sessions without taking drugs. Passing from the "off" to the "on" state, only low performer PD patients significantly improved their performance on high-flexibility measures (interference condition of the Stroop test; P < 0.05); no significant effect was found on low-flexibility tasks. These findings document that high-flexibility processes are sensitive to dopamine neuromodulation in the early phases of PD. This is in line with the hypothesis that striatal dopamine pathways, affected early by PD, are precociously implicated in the expression of cognitive disorders in these individuals.

Thermodynamic Evaluation of Hydrogen Absorption by Niobium During SRF Fabrication

NASA Astrophysics Data System (ADS)

Ricker, R. E.; Myneni, G. R.

2011-03-01

The properties and performance of the ultra high purity Nb used to fabricate superconducting radio frequency (SRF) particle accelerator cavities have been found to vary with processing conditions. One hypothesis for these variations is that hydrogen, absorbed during processing, is responsible for this behavior. The key assumption behind this hypothesis is that niobium can absorb hydrogen from one or more of the processing environments. This paper reviews work examining the validity of this assumption. It was determined that Nb will spontaneously react with water producing adsorbed atomic hydrogen that is readily absorbed into the metal. The passivating oxide film normally prevents this reaction, but this film is frequently removed during processing and it is attacked by the fluoride ion used in the polishing solutions for SRF cavities. However, during electropolishing that cathodic reduction of hydrogen is transferred to the auxiliary electrode and this should suppress hydrogen absorption.

In situ encapsulation of liquids by means of crystallization

NASA Astrophysics Data System (ADS)

Hartwig, Anne; Ulrich, Joachim

2017-07-01

The in situ encapsulation process is due to its few process steps an innovative and cost effective alternative to common encapsulation techniques. It combines the well-known processes of pastillation and crystallization. This concept is proven with case studies of three xylitol capsules which vary in composition and size. It could be shown that the knowledge concerning the solubility of the components is essential to determine the suitable production conditions. The application of seed crystals and the temperatures during the process have major effects on the capsules quality. A fast crystallization of the capsules results in an instable shell. However, with increasing layer thickness of the shell, the crushing force that needs to be applied to break the capsules is increasing as well. But the stability which is related to the capsules size is decreasing with increasing diameter, even though layer thickness and crushing force are increasing, too.

The role of economic strain on adolescent delinquency: a microsocial process model.

PubMed

Low, Sabina; Sinclair, Ryan; Shortt, Joann Wu

2012-08-01

The current study examines the role of economic strain as a moderator of the microsocial processes influencing younger siblings' delinquency (externalizing behavior and substance use) in a longitudinal design. The younger siblings (122 younger brothers and 122 younger sisters) were from 244 families with same-sex biological siblings. Structural equation modeling was utilized to examine a process model whereby mothers' harsh/inconsistent parenting and older sibling delinquency influence younger siblings' delinquent behavior via sibling aggression and delinquent peer affiliation. Findings suggest that indirect mechanisms vary as a function of economic strain, with sibling aggression having a stronger, more detrimental effect on adolescent delinquency in economically strained families. Data suggest that familial economic conditions contextualize the relative roles of parenting, sibling, and peer processes in the transmission of risk to adolescent delinquency. PsycINFO Database Record (c) 2012 APA, all rights reserved.

A Comparison of Crater-Size Scaling and Ejection-Speed Scaling During Experimental Impacts in Sand

NASA Technical Reports Server (NTRS)

Anderson, J. L. B.; Cintala, M. J.; Johnson, M. K.

2014-01-01

Non-dimensional scaling relationships are used to understand various cratering processes including final crater sizes and the excavation of material from a growing crater. The principal assumption behind these scaling relationships is that these processes depend on a combination of the projectile's characteristics, namely its diameter, density, and impact speed. This simplifies the impact event into a single point-source. So long as the process of interest is beyond a few projectile radii from the impact point, the point-source assumption holds. These assumptions can be tested through laboratory experiments in which the initial conditions of the impact are controlled and resulting processes measured directly. In this contribution, we continue our exploration of the congruence between crater-size scaling and ejection-speed scaling relationships. In particular, we examine a series of experimental suites in which the projectile diameter and average grain size of the target are varied.

Seasonal dependence of aerosol processing in urban Philadelphia

NASA Astrophysics Data System (ADS)

Avery, A. M.; Waring, M. S.; DeCarlo, P. F.

2017-12-01

Urban aerosols pose an important threat to human health due to the conflation of emissions and concentrated population exposed. Winter and summer aerosol and trace gas measurements were taken in downtown Philadelphia in 2016. Measurements included aerosol composition and size with an Aerodyne Aerosol Mass Spectrometer (AMS), particle size distributions with an SMPS, and an aethalometer. Trace gas measurements of O3, NO, CH4, CO, and CO2 were taken concurrently. Sampling in seasonal extremes provided contrast in aerosol and trace gas composition, aerosol processing, and emission factors. Inorganic aerosol components contributed approximately 60% of the submicron aerosol mass, while summertime aerosol composition was roughly 70% organic matter. Positive Matrix Factorization (PMF) on the organic aerosol (OA) matrix revealed three factors in common in each season, including an oxygenated organic aerosol (OOA) factor with different temporal behavior in each season. In summertime, OOA varied diurnally with ozone and daytime temperature, but in the wintertime, it was anti-correlated with ozone and temperature, and instead trended with calculated liquid water, indicating a seasonally-dependent processing of organic aerosol in Philadelphia's urban environment. Due to the inorganic dominant winter aerosol, liquid water much higher (2.65 μg/m3) in winter than in summer (1.54 μg/m3). Diurnally varying concentrations of background gas phase species (CH4, CO2) were higher in winter and varied less as a result of boundary layer conditions; ozone was also higher in background in winter than summer. Winter stagnation events with low windspeed showed large buildup of trace gases CH4, CO, CO2, and NO. Traffic related aerosol was also elevated with black carbon and hydrocarbon-like OA (HOA) plumes of each at 3-5 times higher than the winter the average value for each. Winter ratios of HOA to black carbon were significantly higher in the winter than the summer due to lower temperatures. Aerosol compositional differences in winter and summer indicate Philadelphia resident's aerosol exposures vary significantly with season.

Word Skipping During Sentence Reading: Effects of Lexicality on Parafoveal Processing

PubMed Central

Choi, Wonil; Gordon, Peter C.

2013-01-01

Two experiments examined how lexical status affects the targeting of saccades during reading by using the boundary technique to vary independently the content of a letter string when seen in parafoveal preview and when directly fixated. Experiment 1 measured the skipping rate for a target word embedded in a sentence under three parafoveal preview conditions: full preview (e.g. brain-brain), pseudohomophone preview (e.g. brane-brain), and orthographic nonword control preview (e.g. brant-brain); in the first condition the preview string was always an English word while in the second and third conditions it was always a nonword. Experiment 2 investigated three conditions where the preview string was always a word: full preview (e.g. beach-beach), homophone preview (e.g. beech-beach), and orthographic control preview (e.g. bench-beach). None of the letter string manipulations used to create the preview conditions in the experiments disrupted sub-lexical orthographic or phonological patterns. In Experiment 1 higher skipping rates were observed for the full (lexical) preview condition, which consisted of a word, compared to the nonword preview conditions (pseudohomophone and orthographic-control). In contrast Experiment 2 showed no difference in skipping rates across the three types of lexical preview conditions (full, homophone and orthographic control), though preview type did influence reading times. This pattern indicates that skipping depends not only on the presence of disrupted sub-lexical patterns of orthography or phonology but is also critically dependent on processes that are sensitive to the lexical status of letter strings in the parafovea. PMID:24170376

An evaluation of models of bare soil evaporation formulated with different land surface boundary conditions and assumptions

NASA Astrophysics Data System (ADS)

Smits, Kathleen M.; Ngo, Viet V.; Cihan, Abdullah; Sakaki, Toshihiro; Illangasekare, Tissa H.

2012-12-01

Bare soil evaporation is a key process for water exchange between the land and the atmosphere and an important component of the water balance. However, there is no agreement on the best modeling methodology to determine evaporation under different atmospheric boundary conditions. Also, there is a lack of directly measured soil evaporation data for model validation to compare these methods to establish the validity of their mathematical formulations. Thus, a need exists to systematically compare evaporation estimates using existing methods to experimental observations. The goal of this work is to test different conceptual and mathematical formulations that are used to estimate evaporation from bare soils to critically investigate various formulations and surface boundary conditions. Such a comparison required the development of a numerical model that has the ability to incorporate these boundary conditions. For this model, we modified a previously developed theory that allows nonequilibrium liquid/gas phase change with gas phase vapor diffusion to better account for dry soil conditions. Precision data under well-controlled transient heat and wind boundary conditions were generated, and results from numerical simulations were compared with experimental data. Results demonstrate that the approaches based on different boundary conditions varied in their ability to capture different stages of evaporation. All approaches have benefits and limitations, and no one approach can be deemed most appropriate for every scenario. Comparisons of different formulations of the surface boundary condition validate the need for further research on heat and vapor transport processes in soil for better modeling accuracy.

Gas emission from the UO2 samples, containing fission products and burnable absorber

NASA Astrophysics Data System (ADS)

Kopytin, V. P.; Baranov, V. G.; Burlakova, M. A.; Tenishev, A. V.; Kuzmin, R. S.; Pokrovskiy, S. A.; Mikhalchik, V. V.

2016-04-01

The process gas released from the fuel pellets of uranium fuel during fuel burn-up reduces the thermal conductivity of the rod-shell gap, enhances hydrogen embrittlement of the cladding material, causes it's carbonization, as well as transport processes in the fuel. In this study a technique of investigating the thermal desorption of gases from the UO2 fuel material were perfected in the temperature range 300-2000 K for uniform sample heating rate of 15 K/min in vacuum. The characteristic kinetic dependences are acquired for the gas emission from UO2 samples, containing simulators of fission products (SFP) and the burnable neutron absorber (BNA). Depending on the amount of SFP and BNA contained in the sample thermal desorption gas spectra (TDGS) vary. The composition of emitted gas varies, as well as the number of peaks in the TDGS and the peaks shift to higher temperatures. This indicates that introduction of SFPs and BNA alters the sample material structure and cause the creation of so- called traps which have different bonding energies to the gases. The traps can be a grid of dislocations, voids, and contained in the UO2 matrix SFP and BNA. Similar processes will occur in the fuel pellets in the real conditions of the Nuclear Power Plant as well.

Temporal expectancy in the context of a theory of visual attention

PubMed Central

Vangkilde, Signe; Petersen, Anders; Bundesen, Claus

2013-01-01

Temporal expectation is expectation with respect to the timing of an event such as the appearance of a certain stimulus. In this paper, temporal expectancy is investigated in the context of the theory of visual attention (TVA), and we begin by summarizing the foundations of this theoretical framework. Next, we present a parametric experiment exploring the effects of temporal expectation on perceptual processing speed in cued single-stimulus letter recognition with unspeeded motor responses. The length of the cue–stimulus foreperiod was exponentially distributed with one of six hazard rates varying between blocks. We hypothesized that this manipulation would result in a distinct temporal expectation in each hazard rate condition. Stimulus exposures were varied such that both the temporal threshold of conscious perception (t0 ms) and the perceptual processing speed (v letters s−1) could be estimated using TVA. We found that the temporal threshold t0 was unaffected by temporal expectation, but the perceptual processing speed v was a strikingly linear function of the logarithm of the hazard rate of the stimulus presentation. We argue that the effects on the v values were generated by changes in perceptual biases, suggesting that our perceptual biases are directly related to our temporal expectations. PMID:24018716

Irradiation-induced Ag-colloid formation in ion-exchanged soda-lime glass

NASA Astrophysics Data System (ADS)

Caccavale, F.; De Marchi, G.; Gonella, F.; Mazzoldi, P.; Meneghini, C.; Quaranta, A.; Arnold, G. W.; Battaglin, G.; Mattei, G.

1995-03-01

Ion-exchanged glass samples were obtained by immersing soda-lime slides in molten salt baths of molar concentration in the range 1-20% AgNO 3 in NaNO 3, at temperatures varying from 320 to 350°C, and processing times of the order of a few minutes. Irradiations of exchanged samples were subsequently performed by using H +m, He +, N + ions at different energies in order to obtain comparable projected ranges. The fluence was varied between 5 × 10 15 and 2 × 10 17 ions/cm 2. Most of the samples were treated at current densities lower than 2 μA/cm 2, in order to avoid heating effects. Some samples were irradiated with 4 keV electrons, corresponding to a range of 250 nm. The formation of nanoclusters of radii in the range 1-10 nm has been observed after irradiation, depending on the treatment conditions. The precipitation process is governed by the electronic energy deposition of incident particles. The most desirable results are obtained for helium implants. The process was characterized by the use of Secondary Ion Mass Spectrometry (SIMS) and nuclear techniques (Rutherford Backscattering (RBS), Nuclear Reactions (NRA)), in order to determine concentration-depth profiles and by optical absorption and Transmission Electron Microscopy (TEM) measurements for the silver nanoclusters detection and size evaluation.

Zinc oxide nanostructures and its nano-compounds for efficient visible light photo-catalytic processes

NASA Astrophysics Data System (ADS)

Adam, Rania E.; Alnoor, Hatim; Elhag, Sami; Nur, Omer; Willander, Magnus

2017-02-01

Zinc oxide (ZnO) in its nanostructure form is a promising material for visible light emission/absorption and utilization in different energy efficient photocatalytic processes. We will first present our recent results on the effect of varying the molar ratio of the synthesis nutrients on visible light emission. Further we will use the optimized conditions from the molar ration experiments to vary the synthesis processing parameters like stirring time etc. and the effect of all these parameters in order to optimize the efficiency and control the emission spectrum are investigated using different complementary techniques. Cathodoluminescence (CL) is combined with photoluminescence (PL) and electroluminescence (EL) as the techniques to investigate and optimizes visible light emission from ZnO/GaN light emitting diodes. We will then show and discuss our recent finding of the use of high quality ZnO nanoparticles (NPs) for efficient photo-degradation of toxic dyes using the visible spectra, namely with a wavelength up to 800 nm. In the end, we show how ZnO nanorods (NRs) are used as the first template to be transferred to bismuth zinc vanadate (BiZn2VO6). The BiZn2VO6 is then used to demonstrate efficient and cost effective hydrogen production through photoelectrochemical water splitting using solar radiation.

Refining the Enrolment Process in Emergency Medicine Research.

PubMed

Sahan, Kate M; Channon, Keith M; Choudhury, Robin P; Kharbanda, Rajesh K; Lee, Regent; Sheehan, Mark

2016-04-01

Research in the emergency setting involving patients with acute clinical conditions is needed if there are to be advances in diagnosis and treatment. But research in these areas poses ethical and practical challenges. One of these is the general inability to obtain informed consent due to the patient's lack of mental capacity and insufficient time to contact legal representatives. Regulatory frameworks which allow this research to proceed with a consent 'waiver', provided patients lack mental capacity, miss important ethical subtleties. One of these is the varying nature of mental capacity among emergency medicine patients. Not only is their capacity variable and often unclear, but some patients are also likely to be able to engage with the researcher and the context to varying degrees. In this paper we describe the key elements of a novel enrolment process for emergency medicine research that refines the consent waiver and fully engages with the ethical rationale for consent and, in this context, its waiver. The process is verbal but independently documented during the 'emergent' stages of the research. It provides appropriate engagement with the patient, is context-sensitive and better addresses ethical subtleties. In line with regulation, full written consent for on-going participation in the research is obtained once the emergency is passed.

Top-down and bottom-up competition in visual stimuli processing.

PubMed

Ligeza, Tomasz S; Tymorek, Agnieszka D; Wyczesany, Mirosław

2017-01-01

Limited attention capacity results that not all the stimuli present in the visual field are equally processed. While processing of salient stimuli is automatically boosted by bottom‑up attention, processing of task‑relevant stimuli can be boosted volitionally by top‑down attention. Usually, both top‑down and bottom‑up influences are present simultaneously, which creates a competition between these two types of attention. We examined this competition using both behavioral and electrophysiological measures. Participants responded to letters superimposed on background pictures. We assumed that responding to different conditions of the letter task engages top‑down attention to different extent, whereas processing of background pictures of varying salience engages bottom‑up attention to different extent. To check how manipulation of top‑down attention influences bottom‑up processing, we measured evoked response potentials (ERPs) in response to pictures (engaging mostly bottom‑up attention) during three conditions of a letter task (different levels of top‑down engagement). Conversely, to check how manipulation of bottom‑up attention influences top‑down processing, we measured ERP responses for letters (engaging mostly top‑down attention) while manipulating the salience of background pictures (different levels of bottom‑up engagement). The correctness and reaction times in response to letters were also analyzed. As expected, most of the ERPs and behavioral measures revealed a trade‑off between both types of processing: a decrease of bottom‑up processing was associated with an increase of top‑down processing and, similarly, a decrease of top‑down processing was associated with an increase in bottom‑up processing. Results proved competition between the two types of attentions.

Synthesis and analysis of jet fuel from shale oil and coal syncrudes

NASA Technical Reports Server (NTRS)

Gallagher, J. P.; Collins, T. A.; Nelson, T. J.; Pedersen, M. J.; Robison, M. G.; Wisinski, L. J.

1976-01-01

Thirty-two jet fuel samples of varying properties were produced from shale oil and coal syncrudes, and analyzed to assess their suitability for use. TOSCO II shale oil and H-COAL and COED syncrudes were used as starting materials. The processes used were among those commonly in use in petroleum processing-distillation, hydrogenation and catalytic hydrocracking. The processing conditions required to meet two levels of specifications regarding aromatic, hydrogen, sulfur and nitrogen contents at two yield levels were determined and found to be more demanding than normally required in petroleum processing. Analysis of the samples produced indicated that if the more stringent specifications of 13.5% hydrogen (min.) and 0.02% nitrogen (max.) were met, products similar in properties to conventional jet fuels were obtained. In general, shale oil was easier to process (catalyst deactivation was seen when processing coal syncrudes), consumed less hydrogen and yielded superior products. Based on these considerations, shale oil appears to be preferred to coal as a petroleum substitute for jet fuel production.

An automated distinction of DICOM images for lung cancer CAD system

NASA Astrophysics Data System (ADS)

Suzuki, H.; Saita, S.; Kubo, M.; Kawata, Y.; Niki, N.; Nishitani, H.; Ohmatsu, H.; Eguchi, K.; Kaneko, M.; Moriyama, N.

2009-02-01

Automated distinction of medical images is an important preprocessing in Computer-Aided Diagnosis (CAD) systems. The CAD systems have been developed using medical image sets with specific scan conditions and body parts. However, varied examinations are performed in medical sites. The specification of the examination is contained into DICOM textual meta information. Most DICOM textual meta information can be considered reliable, however the body part information cannot always be considered reliable. In this paper, we describe an automated distinction of DICOM images as a preprocessing for lung cancer CAD system. Our approach uses DICOM textual meta information and low cost image processing. Firstly, the textual meta information such as scan conditions of DICOM image is distinguished. Secondly, the DICOM image is set to distinguish the body parts which are identified by image processing. The identification of body parts is based on anatomical structure which is represented by features of three regions, body tissue, bone, and air. The method is effective to the practical use of lung cancer CAD system in medical sites.

High heat flux performance of W-Eurofer brazed joints

NASA Astrophysics Data System (ADS)

de Prado, J.; Sánchez, M.; Wirtz, M.; Pintsuk, G.; Du, J.; Linke, J.; Ureña, A.

2018-02-01

The qualification process of the materials and components for the next generation of fusion reactors makes it necessary to expose them to similar service conditions as expected during the service life of the reactor. In the present work, W-Eurofer brazed joints (tungsten block: 8 × 8 × 4 mm; steel block: 8 × 8 × 4 mm; joined to an actively cooled copper heat sink) were exposed to steady state heat loads to study the effect of the thermal fatigue on their microstructure and mechanical integrity. Three different W surface temperatures were tested (400, 500 and 600 °C) varying the number of applied cycles (100 and 1000). The results allowed identifying a braze temperature of 359 °C as threshold condition under which the brazed joints could be used without deterioration. The increase of the surface temperature deteriorated the mechanical integrity of the joints in comparison to those analyzed after the brazing process and accordingly reduced the refrigeration capabilities.

Microbial enzymes with special characteristics for biotechnological applications.

PubMed

Nigam, Poonam Singh

2013-08-23

This article overviews the enzymes produced by microorganisms, which have been extensively studied worldwide for their isolation, purification and characterization of their specific properties. Researchers have isolated specific microorganisms from extreme sources under extreme culture conditions, with the objective that such isolated microbes would possess the capability to bio-synthesize special enzymes. Various Bio-industries require enzymes possessing special characteristics for their applications in processing of substrates and raw materials. The microbial enzymes act as bio-catalysts to perform reactions in bio-processes in an economical and environmentally-friendly way as opposed to the use of chemical catalysts. The special characteristics of enzymes are exploited for their commercial interest and industrial applications, which include: thermotolerance, thermophilic nature, tolerance to a varied range of pH, stability of enzyme activity over a range of temperature and pH, and other harsh reaction conditions. Such enzymes have proven their utility in bio-industries such as food, leather, textiles, animal feed, and in bio-conversions and bio-remediations.

Tuning polymorphism and orientation in organic semiconductor thin films via post-deposition processing.

PubMed

Hiszpanski, Anna M; Baur, Robin M; Kim, Bumjung; Tremblay, Noah J; Nuckolls, Colin; Woll, Arthur R; Loo, Yueh-Lin

2014-11-05

Though both the crystal structure and molecular orientation of organic semiconductors are known to impact charge transport in thin-film devices, separately accessing different polymorphs and varying the out-of-plane molecular orientation is challenging, typically requiring stringent control over film deposition conditions, film thickness, and substrate chemistry. Here we demonstrate independent tuning of the crystalline polymorph and molecular orientation in thin films of contorted hexabenzocoronene, c-HBC, during post-deposition processing without the need to adjust deposition conditions. Three polymorphs are observed, two of which have not been previously reported. Using our ability to independently tune the crystal structure and out-of-plane molecular orientation in thin films of c-HBC, we have decoupled and evaluated the effects that molecular packing and orientation have on device performance in thin-film transistors (TFTs). In the case of TFTs comprising c-HBC, polymorphism and molecular orientation are equally important; independently changing either one affects the field-effect mobility by an order of magnitude.

Stress-corrosion behavior of aluminum-lithium alloys in aqueous salt environments

NASA Technical Reports Server (NTRS)

Pizzo, P. P.; Galvin, R. P.; Nelson, H. G.

1984-01-01

The stress corrosion susceptibility of two powder metallurgy (P/M) alloys, Al-Li-Cu and Al-Li-Cu-Mg; two mechanically attrited (M/A) alloys, Al-Li-Cu and Al-Li-Mg; and two wrought, ingot alloys, X-2020 and AA7475, are compared. Time-dependent fracture in an aqueous sodium chloride environment under alternate immersion condition was found to vary significantly between alloys. The stress corrosion behavior of the two powder metallurgy processed alloys was studied in detail under conditions of crack initiation, static crack growth, and fatigue crack growth. A variety of stress corrosion tests were performed including smooth surface, time-to-failure tests; potentiostatic tests on smooth surfaces exposed to constant applied strain rates; and fracture mechanics-type tests under static and cyclic loads. Both alloys show surface pitting and subsequent intergranular corrosion. Pitting is more severe in the magnesium-bearing alloy and is associated with stringer particles strung along the extrusion direction as a result of P/M processing.

Simulation of 2D Waves in Circular Membrane Using Excel Spreadsheet with Visual Basic for Teaching Activity

NASA Astrophysics Data System (ADS)

Eso, R.; Safiuddin, L. O.; Agusu, L.; Arfa, L. M. R. F.

2018-04-01

We propose a teaching instrument demonstrating the circular membrane waves using the excel interactive spreadsheets with the Visual Basic for Application (VBA) programming. It is based on the analytic solution of circular membrane waves involving Bessel function. The vibration modes and frequencies are determined by using Bessel approximation and initial conditions. The 3D perspective based on the spreadsheets functions and facilities has been explored to show the 3D moving objects in transitional or rotational processes. This instrument is very useful both in teaching activity and learning process of wave physics. Visualizing of the vibration of waves in the circular membrane which is showing a very clear manner of m and n vibration modes of the wave in a certain frequency has been compared and matched to the experimental result using resonance method. The peak of deflection varies in time if the initial condition was working and have the same pattern with matlab simulation in zero initial velocity

The time course of perceptual grouping: the role of segregation and shape formation.

PubMed

Razpurker-Apfeld, Irene; Kimchi, Ruth

2007-07-01

The time course of perceptual grouping was examined in two experiments, using a primed matching task. In different conditions, elements were grouped into columns/rows by common lightness, into a shape (triangle/ arrow or square/cross) by common lightness, and into a shape without segregation of elements. The results showed an early and rapid grouping into columns/rows by common lightness and into a shape when no segregation from other elements was involved. Goodness of shape (i.e., triangle/arrow vs. square/cross) had no influence on how early grouping was evident, but the relatively poorer shapes appeared to consolidate with time. In contrast, grouping into a shape that involved segregation and required resolving figure-ground relations between segregated units, as grouping into a shape by common lightness, consumed time, regardless of shape goodness. These results suggest that the time course of grouping varies as a function of the processes involved in it (e.g., segregation and shape formation) and the conditions prevailing for each process.

Polymer deformation and filling modes during microembossing

NASA Astrophysics Data System (ADS)

Rowland, Harry D.; King, William P.

2004-12-01

This work investigates the initial stages of polymer deformation during hot embossing micro-manufacturing at processing temperatures near the glass transition temperature (Tg) of polymer films having sufficient thickness such that polymer flow is not supply limited. Several stages of polymer flow can be observed by employing stamp geometries of various widths and varying imprint conditions of time and temperature to modulate polymer viscosity. Experiments investigate conditions affecting cavity filling phenomena, including apparent polymer viscosity. Stamps with periodic ridges of height and width 4 µm and periodicity 30, 50 and 100 µm emboss trenches into polymethyl methacrylate films at Tg - 10 °C < Temboss < Tg + 20 °C. Imprint parameters of time, temperature and load are correlated with replicated polymer shape, height and imprinted area. Polymer replicates are measured by atomic force microscopy and inspected by scanning electron microscopy. Cavity size and the temperature dependence of polymer viscosity significantly influence the nature of polymer deformation in hot embossing micro-manufacturing and must be accounted for in rational process design.

Effect of initial conditions on constant pressure mixing between two turbulent streams

NASA Astrophysics Data System (ADS)

Kangovi, S.

1983-02-01

It is pointed out that a study of the process of mixing between two dissimilar streams has varied applications in different fields. The applications include the design of an after burner in a high by-pass ratio aircraft engine and the disposal of effluents in a stream. The mixing process determines important quantities related to the energy transfer from main stream to the secondary stream, the temperature and velocity profiles, and the local kinematic and dissipative structure within the mixing region, and the growth of the mixing layer. Hill and Page (1968) have proposed the employment of an 'assumed epsilon' method in which the eddy viscosity model of Goertler (1942) is modified to account for the initial boundary layer. The present investigation is concerned with the application of the assumed epsilon technique to the study of the effect of initial conditions on the development of the turbulent mixing layer between two compressible, nonisoenergetic streams at constant pressure.

Multiple sites of extinction for a single learned response

PubMed Central

Mauk, Michael D.

2012-01-01

Most learned responses can be diminished by extinction, a process that can be engaged when a conditioned stimulus (CS) is presented but not reinforced. We present evidence that plasticity in at least two brain regions can mediate extinction of responses produced by trace eyelid conditioning, where the CS and the reinforcing stimulus are separated by a stimulus-free interval. We observed individual differences in the effects of blocking extinction mechanisms in the cerebellum, the structure that, along with several forebrain structures, mediates acquisition of trace eyelid responses; in some rabbits extinction was prevented, whereas in others it was largely unaffected. We also show that cerebellar mechanisms can mediate extinction when noncerebellar mechanisms are bypassed. Together, these observations indicate that trace eyelid responses can be extinguished via processes operating at more than one site, one in the cerebellum and one upstream in forebrain. The relative contributions of these sites may vary from animal to animal and situation to situation. PMID:21940608

Stress-corrosion behavior of aluminum-lithium alloys in aqueous environments

NASA Technical Reports Server (NTRS)

Pizzo, P. P.; Galvin, R. P.; Nelson, H. G.

1983-01-01

The stress corrosion susceptibility of two powder metallurgy (P/M) alloys, Al-Li-Cu and Al-Li-Cu-Mg two mechanically attrited (M/A) alloys, Al-Li-Cu and Al-Li-Mg; and two wrought, ingot alloys, X-2020 and AA7475, are compared. Time-dependent fracture in an aqueous sodium chloride environment under alternate immersion condition was found to vary significantly between alloys. The stress corrosion behavior of the two powder metallurgy processed alloys was studied in detail under conditions of crack initiation, static crack growth, and fatigue crack growth. A variety of stress corrosion tests were performed including smooth surface, time-to-failure tests; potentiostatic tests on smooth surfaces exposed to constant applied strain rates; and fracture mechanics-type tests under static and cyclic loads. Both alloys show surface pitting and subsequent intergranular corrosion. Pitting is more severe in the magnesium-bearing alloy and is associated with stringer particles strung along the extrusion direction as a result of P/M processing.

In-situ Condition Monitoring of Components in Small Modular Reactors Using Process and Electrical Signature Analysis. Final report, volume 1. Development of experimental flow control loop, data analysis and plant monitoring

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

Upadhyaya, Belle; Hines, J. Wesley; Damiano, Brian

The research and development under this project was focused on the following three major objectives: Objective 1: Identification of critical in-vessel SMR components for remote monitoring and development of their low-order dynamic models, along with a simulation model of an integral pressurized water reactor (iPWR). Objective 2: Development of an experimental flow control loop with motor-driven valves and pumps, incorporating data acquisition and on-line monitoring interface. Objective 3: Development of stationary and transient signal processing methods for electrical signatures, machinery vibration, and for characterizing process variables for equipment monitoring. This objective includes the development of a data analysis toolbox. Themore » following is a summary of the technical accomplishments under this project: - A detailed literature review of various SMR types and electrical signature analysis of motor-driven systems was completed. A bibliography of literature is provided at the end of this report. Assistance was provided by ORNL in identifying some key references. - A review of literature on pump-motor modeling and digital signal processing methods was performed. - An existing flow control loop was upgraded with new instrumentation, data acquisition hardware and software. The upgrading of the experimental loop included the installation of a new submersible pump driven by a three-phase induction motor. All the sensors were calibrated before full-scale experimental runs were performed. - MATLAB-Simulink model of a three-phase induction motor and pump system was completed. The model was used to simulate normal operation and fault conditions in the motor-pump system, and to identify changes in the electrical signatures. - A simulation model of an integral PWR (iPWR) was updated and the MATLAB-Simulink model was validated for known transients. The pump-motor model was interfaced with the iPWR model for testing the impact of primary flow perturbations (upsets) on plant parameters and the pump electrical signatures. Additionally, the reactor simulation is being used to generate normal operation data and data with instrumentation faults and process anomalies. A frequency controller was interfaced with the motor power supply in order to vary the electrical supply frequency. The experimental flow control loop was used to generate operational data under varying motor performance characteristics. Coolant leakage events were simulated by varying the bypass loop flow rate. The accuracy of motor power calculation was improved by incorporating the power factor, computed from motor current and voltage in each phase of the induction motor.- A variety of experimental runs were made for steady-state and transient pump operating conditions. Process, vibration, and electrical signatures were measured using a submersible pump with variable supply frequency. High correlation was seen between motor current and pump discharge pressure signal; similar high correlation was exhibited between pump motor power and flow rate. Wide-band analysis indicated high coherence (in the frequency domain) between motor current and vibration signals. - Wide-band operational data from a PWR were acquired from AMS Corporation and used to develop time-series models, and to estimate signal spectrum and sensor time constant. All the data were from different pressure transmitters in the system, including primary and secondary loops. These signals were pre-processed using the wavelet transform for filtering both low-frequency and high-frequency bands. This technique of signal pre-processing provides minimum distortion of the data, and results in a more optimal estimation of time constants of plant sensors using time-series modeling techniques.« less

The Metabolic Syndrome and the Relevance of Nutrients for its Onset.

PubMed

Schnack, Lauren L; Romani, Andrea M P

2017-01-01

Metabolic Syndrome is a pathological condition characterized by the copresence of various dysmetabolic and pathological processes including hypertension, dyslipidemia, type 2 diabetes mellitus, obesity, and cardiovascular complications. Because these conditions manifest themselves differently in a given patient, the ensuing pathophysiological state varies from patient to patient. Consequently, the order in which signs and symptoms manifest themselves can vary, making difficult to establish cause-effect relationship, and efficacious treatment and prevention options. Furthermore, the available therapeutic options do not necessarily apply in an effective manner to all patients due to the modality of the syndrome's onset and progression, and the fact that each patient presents different clinical manifestations. Where do the metabolic disturbances originate? Genetic predisposition, maternal health, age, and ethnicity are possible influential factors, which put individuals at higher risk for developing metabolic defects. More recently, dietary factors and deficiency in key macro- and micro-nutrients have been indicated as key players in the onset and progression of the disease. We revised all possible patents applying to this topic. Aside from pharmacological agents used to treat specific medical conditions, no patents were observed to be registered for specific dietary macro- and micro-nutrients. The present review attempts to provide a framework to help the reader understand the causes behind the development of the metabolic syndrome and its complication. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Factors Influencing Dwell Fatigue Cracking in Notches of Powder Metallurgy Superalloys

NASA Technical Reports Server (NTRS)

Gabb, T. P.; Telesman, J.; Ghosn, L.; Garg, A.; Gayda, J.

2011-01-01

The influences of heat treatment and cyclic dwells on the notch fatigue resistance of powder metallurgy disk superalloys were investigated for low solvus high refractory (LSHR) and ME3 disk alloys. Disks were processed to produce material conditions with varied microstructures and associated mechanical properties. Notched specimens were first subjected to baseline dwell fatigue cycles having a dwell at maximum load, as well as tensile, stress relaxation, creep rupture, and dwell fatigue crack growth tests at 704 C. Several material heat treatments displayed a bimodal distribution of fatigue life with the lives varying by two orders-of-magnitude, while others had more consistent fatigue lives. This response was compared to other mechanical properties, in search of correlations. The wide scatter in baseline dwell fatigue life was observed only for material conditions resistant to stress relaxation. For selected materials and conditions, additional tests were then performed with the dwells shifted in part or in total to minimum tensile load. The tests performed with dwells at minimum load exhibited lower fatigue lives than max dwell tests, and also exhibited early crack initiation and a substantial increase in the number of initiation sites. These results could be explained in part by modeling evolution of peak stresses in the notch with continued dwell fatigue cycling. Fatigue-environment interactions were determined to limit life for the fatigue cycles with dwells.

Importance of interactions between food quality, quantity, and gut transit time on consumer feeding, growth, and trophic dynamics.

PubMed

Mitra, Aditee; Flynn, Kevin J

2007-05-01

Ingestion kinetics of animals are controlled by both external food availability and feedback from the quantity of material already within the gut. The latter varies with gut transit time (GTT) and digestion of the food. Ingestion, assimilation efficiency, and thus, growth dynamics are not related in a simple fashion. For the first time, the important linkage between these processes and GTT is demonstrated; this is achieved using a biomass-based, mechanistic multinutrient model fitted to experimental data for zooplankton growth dynamics when presented with food items of varying quality (stoichiometric composition) or quantity. The results show that trophic transfer dynamics will vary greatly between the extremes of feeding on low-quantity/high-quality versus high-quantity/low-quality food; these conditions are likely to occur in nature. Descriptions of consumer behavior that assume a constant relationship between the kinetics of grazing and growth irrespective of food quality and/or quantity, with little or no recognition of the combined importance of these factors on consumer behavior, may seriously misrepresent consumer activity in dynamic situations.

Facile control of silica nanoparticles using a novel solvent varying method for the fabrication of artificial opal photonic crystals

NASA Astrophysics Data System (ADS)

Gao, Weihong; Rigout, Muriel; Owens, Huw

2016-12-01

In this work, the Stöber process was applied to produce uniform silica nanoparticles (SNPs) in the meso-scale size range. The novel aspect of this work was to control the produced silica particle size by only varying the volume of the solvent ethanol used, whilst fixing the other reaction conditions. Using this one-step Stöber-based solvent varying (SV) method, seven batches of SNPs with target diameters ranging from 70 to 400 nm were repeatedly reproduced, and the size distribution in terms of the polydispersity index (PDI) was well maintained (within 0.1). An exponential equation was used to fit the relationship between the particle diameter and ethanol volume. This equation allows the prediction of the amount of ethanol required in order to produce particles of any target diameter within this size range. In addition, it was found that the reaction was completed in approximately 2 h for all batches regardless of the volume of ethanol. Structurally coloured artificial opal photonic crystals (PCs) were fabricated from the prepared SNPs by self-assembly under gravity sedimentation.

A mind in a disk: the attribution of mental states to technological systems.

PubMed

Parlangeli, Oronzo; Chiantini, Tommaso; Guidi, Stefano

2012-01-01

This paper reports a study about the role of different variables in the process of attributing mental states to technological systems, variables such as the number of figural elements displayed in the system and the personality traits of the subjects interacting with the systems. In an experiment, participants were interacting with a computer on whose screen several disks of various sizes and colours were blinking at different rates. Each time a disk reappeared on the screen its position was randomly varied. As in a videogame, participants had to click on the disks to increase their score. The results showed that, even in the case of such a simple system, subjects believed that the figural elements they were interacting with had some form of mental states, although their confidence in these beliefs varied in the different experimental conditions. The confidence level of the attributions, in fact, was not the same for all the different mental states considered, and it varied also both with the number of elements being displayed as well as with some personality traits of the subjects.

Combustion of a Polymer (PMMA) Sphere in Microgravity

NASA Technical Reports Server (NTRS)

Yang, Jiann C.; Hamins, Anthony; Donnelly, Michelle K.

1999-01-01

A series of low gravity, aircraft-based, experiments was conducted to investigate the combustion of supported thermoplastic polymer spheres under varying ambient conditions. The three types of thermoplastic investigated were polymethylmethacrylate (PMMA), polypropylene (PP). and polystyrene (PS). Spheres with diameters ranging from 2 mm to 6.35 mm were tested. The total initial pressure varied from 0.05 MPa to 0. 15 MPa whereas the ambient oxygen concentration varied from 19 % to 30 % (by volume). The ignition system consisted of a pair of retractable energized coils. Two CCD cameras recorded the burning histories of the spheres. The video sequences revealed a number of dynamic events including bubbling and sputtering, as well as soot shell formation and break-up during combustion of the spheres at reduced gravity. The ejection of combusting material from the burning spheres represents a fire hazard that must be considered at reduced gravity. The ejection process was found to be sensitive to polymer type. All average burning rates were measured to increase with initial sphere diameter and oxygen concentration, whereas the initial pressure had little effect. The three thermoplastic types exhibited different burning characteristics. For the same initial conditions, the burning rate of PP was slower than PMMA, whereas the burning rate of PS was comparable to PMMA. The transient diameter of the burning thermoplastic exhibited two distinct periods: an initial period (enduring approximately half of the total burn duration) when the diameter remained approximately constant, and a final period when the square of the diameter linearly decreased with time. A simple homogeneous two-phase model was developed to understand the changing diameter of the burning sphere. Its value is based on a competition between diameter reduction due to mass loss from burning and sputtering, and diameter expansion due to the processes of swelling (density decrease with heating) and bubble growth. The model relies on empirical parameters for input, such as the burning rate and the duration of the initial and final burning periods.

The Impact of Deliberative Strategy Dissociates ERP Components Related to Conflict Processing vs. Reinforcement Learning

PubMed Central

Warren, Christopher M.; Holroyd, Clay B.

2012-01-01

We applied the event-related brain potential (ERP) technique to investigate the involvement of two neuromodulatory systems in learning and decision making: The locus coeruleus–norepinephrine system (NE system) and the mesencephalic dopamine system (DA system). We have previously presented evidence that the N2, a negative deflection in the ERP elicited by task-relevant events that begins approximately 200 ms after onset of the eliciting stimulus and that is sensitive to low-probability events, is a manifestation of cortex-wide noradrenergic modulation recruited to facilitate the processing of unexpected stimuli. Further, we hold that the impact of DA reinforcement learning signals on the anterior cingulate cortex (ACC) produces a component of the ERP called the feedback-related negativity (FRN). The N2 and the FRN share a similar time range, a similar topography, and similar antecedent conditions. We varied factors related to the degree of cognitive deliberation across a series of experiments to dissociate these two ERP components. Across four experiments we varied the demand for a deliberative strategy, from passively watching feedback, to more complex/challenging decision tasks. Consistent with our predictions, the FRN was largest in the experiment involving active learning and smallest in the experiment involving passive learning whereas the N2 exhibited the opposite effect. Within each experiment, when subjects attended to color, the N2 was maximal at frontal–central sites, and when they attended to gender it was maximal over lateral-occipital areas, whereas the topology of the FRN was frontal–central in both task conditions. We conclude that both the DA system and the NE system act in concert when learning from rewards that vary in expectedness, but that the DA system is relatively more exercised when subjects are relatively more engaged by the learning task. PMID:22493568

Computer Simulations of Deltas with Varying Fluvial Input and Tidal Forcing

NASA Astrophysics Data System (ADS)

Sun, T.

2015-12-01

Deltas are important depositional systems because many large hydrocarbon reservoirs in the world today are found in delta deposits. Deltas form when water and sediments carried by fluvial channels are emptied to an open body of water, and form delta shaped deposits. Depending on the relative importance of the physical processes that controls the forming and the growth of deltas, deltas can often be classified into three different types, namely fluvial, tidal and wave dominated delta. Many previous works, using examples from modern systems, tank experiments, outcrops, and 2 and 3D seismic data sets, have studied the shape, morphology and stratigraphic architectures corresponding to each of the deltas' types. However, few studies have focused on the change of these properties as a function of the relative change of the key controls, and most of the studies are qualitative. Here, using computer simulations, the dynamics of delta evolutions under an increasing amount of tidal influences are studied. The computer model used is fully based on the physics of fluid flow and sediment transport. In the model, tidal influences are taken into account by setting proper boundary conditions that varies both temporally and spatially. The model is capable of capturing many important natural geomorphic and sedimentary processes in fluvial and tidal systems, such as channel initiation, formation of channel levees, growth of mouth bars, bifurcation of channels around channel mouth bars, and channel avulsion. By systematically varying tidal range and fluvial input, the following properties are investigated quantitatively: (1) the presence and the form of tidal beds as a function of tidal range, (2) change of stratigraphic architecture of distributary channel mouth bars or tidal bars as tidal range changes, (3) the transport and sorting of different grainsizes and the overall facie distributions in the delta with different tidal ranges, and (4) the conditions and locations of mud drapes with different magnitude of tidal forcing.

Modeling local chemistry in PWR steam generator crevices

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

Millett, P.J.

1997-02-01

Over the past two decades steam generator corrosion damage has been a major cost impact to PWR owners. Crevices and occluded regions create thermal-hydraulic conditions where aggressive impurities can become highly concentrated, promoting localized corrosion of the tubing and support structure materials. The type of corrosion varies depending on the local conditions, with stress corrosion cracking being the phenomenon of most current concern. A major goal of the EPRI research in this area has been to develop models of the concentration process and resulting crevice chemistry conditions. These models may then be used to predict crevice chemistry based on knowledgemore » of bulk chemistry, thereby allowing the operator to control corrosion damage. Rigorous deterministic models have not yet been developed; however, empirical approaches have shown promise and are reflected in current versions of the industry-developed secondary water chemistry guidelines.« less

Role of naturally occurring osmolytes in protein folding and stability.

PubMed

Kumar, Raj

2009-11-01

Osmolytes are typically accumulated in the intracellular environment at relatively high concentrations when cells/tissues are subjected to stress conditions. Osmolytes are common in a variety of organisms, including microorganisms, plants, and animals. They enhance thermodynamic stability of proteins by providing natively folded conformations without perturbing other cellular processes. By burying the backbone into the core of folded proteins, osmolytes can provide significant stability to proteins. Two properties of osmolytes are particularly important: (i) their ability to impart increased thermodynamic stability to folded proteins; and (ii) their compatibility in the intracellular environment at high concentrations. Under physiological conditions, the cellular compositions of osmolytes may vary significantly. This may lead to different protein folding pathways utilized in cells depending upon the intracellular environment. Proper understanding of the role of osmolytes in cell regulation should allow predicting the action of osmolytes on macromolecular interactions in stressed and crowded environments typical of cellular conditions.