Pioneer neurog1 expressing cells ingress into the otic epithelium and instruct neuronal specification

PubMed Central

Hoijman, Esteban; Fargas, L; Blader, Patrick; Alsina, Berta

2017-01-01

Neural patterning involves regionalised cell specification. Recent studies indicate that cell dynamics play instrumental roles in neural pattern refinement and progression, but the impact of cell behaviour and morphogenesis on neural specification is not understood. Here we combine 4D analysis of cell behaviours with dynamic quantification of proneural expression to uncover the construction of the zebrafish otic neurogenic domain. We identify pioneer cells expressing neurog1 outside the otic epithelium that migrate and ingress into the epithelialising placode to become the first otic neuronal progenitors. Subsequently, neighbouring cells express neurog1 inside the placode, and apical symmetric divisions amplify the specified pool. Interestingly, pioneer cells delaminate shortly after ingression. Ablation experiments reveal that pioneer cells promote neurog1 expression in other otic cells. Finally, ingression relies on the epithelialisation timing controlled by FGF activity. We propose a novel view for otic neurogenesis integrating cell dynamics whereby ingression of pioneer cells instructs neuronal specification. DOI: http://dx.doi.org/10.7554/eLife.25543.001 PMID:28537554

Factors contributing to variability in larval ingress of Atlantic menhaden, Brevoortia tyrannus

NASA Astrophysics Data System (ADS)

Lozano, C.; Houde, E. D.

2013-02-01

Annual recruitment levels of age-0 juvenile Atlantic menhaden to Chesapeake Bay, which historically supported >65% of coastwide recruitment, have been consistently low since the 1980s. Diminished larval supply to the Bay is one hypothesized explanation. In a three-year ichthyoplankton survey at the Chesapeake Bay mouth, abundance of ingressing larvae varied nine-fold among years. Larvae were most abundant in 2007-2008 and less abundant in 2005-2006 and 2006-2007. High month-to-month variability in larval concentrations was attributable primarily to seasonality of occurrences. There was no defined spatial pattern in distribution of larvae across the 18-km-wide Bay mouth, but larvae at the south side were longer and older on average than larvae at the middle and north side. Environmental variables measured at the times of larval collections were not correlated consistently with temporal and spatial variability in abundance of larvae at ingress, highlighting complexity and suggesting that abundance may be controlled by processes occurring offshore during the pre-ingress phase. Moreover, the substantial differences in inter-annual abundances of larvae at the Bay mouth were not concordant with subsequent abundances of age-0 juveniles in the three survey years, indicating that important processes affecting recruitment of Atlantic menhaden operate after ingress, during the larval to juvenile transition stage.

An Undergraduate Experiment for the Measurement of the Speed of Sound in Air: Phenomena and Discussion

ERIC Educational Resources Information Center

Yang, Hujiang; Zhao, Xiaohong; Wang, Xin; Xiao, Jinghua

2012-01-01

In this paper, we present and discuss some phenomena in an undergraduate experiment for the measurement of the speed of sound in air. A square wave distorts when connected to a piezoelectric transducer. Moreover, the amplitude of the receiving signal varies with the driving frequency. Comparing with the Gibbs phenomenon, these phenomena can be…

Myosin II promotes the anisotropic loss of the apical domain during Drosophila neuroblast ingression

PubMed Central

Simões, Sérgio; Oh, Youjin; Wang, Michael F.Z.; Fernandez-Gonzalez, Rodrigo

2017-01-01

Epithelial–mesenchymal transitions play key roles in development and cancer and entail the loss of epithelial polarity and cell adhesion. In this study, we use quantitative live imaging of ingressing neuroblasts (NBs) in Drosophila melanogaster embryos to assess apical domain loss and junctional disassembly. Ingression is independent of the Snail family of transcriptional repressors and down-regulation of Drosophila E-cadherin (DEcad) transcription. Instead, the posttranscriptionally regulated decrease in DEcad coincides with the reduction of cell contact length and depends on tension anisotropy between NBs and their neighbors. A major driver of apical constriction and junctional disassembly are periodic pulses of junctional and medial myosin II that result in progressively stronger cortical contractions during ingression. Effective contractions require the molecular coupling between myosin and junctions and apical relaxation of neighboring cells. Moreover, planar polarization of myosin leads to the loss of anterior–posterior junctions before the loss of dorsal–ventral junctions. We conclude that planar-polarized dynamic actomyosin networks drive apical constriction and the anisotropic loss of cell contacts during NB ingression. PMID:28363972

Ingress in Geography: Portals to Academic Success?

ERIC Educational Resources Information Center

Davis, Michael

2017-01-01

Niantic Labs has developed an augmented virtual reality mobile app game called Ingress in which agents must seek out and control locations for their designated factions. The app uses the Google Maps interface along with GPS to enhance a geocaching-like experience with elements of other classical games such as capture-the-flag. This study aims to…

Liquid ingress recognition in honeycomb structure by pulsed thermography

NASA Astrophysics Data System (ADS)

Chen, Dapeng; Zeng, Zhi; Tao, Ning; Zhang, Cunlin; Zhang, Zheng

2013-05-01

Pulsed thermography has been proven to be a fast and effective method to detect fluid ingress in aircraft honeycomb structure; however, water and hydraulic oil may have similar appearance in the thermal image sequence. It is meaningful to identify what kind of liquid ingress it is for aircraft maintenance. In this study, honeycomb specimens with glass fiber and aluminum skin are injected different kinds of liquids: water and oil. Pulsed thermography is adopted; a recognition method is proposed to first get the reference curve by linear fitting the beginning of the logarithmic curve, and then an algorithm based on the thermal contrast between liquid and reference is used to recognize what kind of fluid it is by calculating their thermal properties. It is verified with the results of theory and the finite element simulation.

Ingression-type cell migration drives vegetal endoderm internalisation in the Xenopus gastrula

PubMed Central

Wen, Jason WH

2017-01-01

During amphibian gastrulation, presumptive endoderm is internalised as part of vegetal rotation, a large-scale movement that encompasses the whole vegetal half of the embryo. It has been considered a gastrulation process unique to amphibians, but we show that at the cell level, endoderm internalisation exhibits characteristics reminiscent of bottle cell formation and ingression, known mechanisms of germ layer internalisation. During ingression proper, cells leave a single-layered epithelium. In vegetal rotation, the process occurs in a multilayered cell mass; we refer to it as ingression-type cell migration. Endoderm cells move by amoeboid shape changes, but in contrast to other instances of amoeboid migration, trailing edge retraction involves ephrinB1-dependent macropinocytosis and trans-endocytosis. Moreover, although cells are separated by wide gaps, they are connected by filiform protrusions, and their migration depends on C-cadherin and the matrix protein fibronectin. Cells move in the same direction but at different velocities, to rearrange by differential migration. PMID:28826499

Daily variation in ingress of fall-spawned larval fishes into Delaware Bay in relation to alongshore and along-estuary wind components

NASA Astrophysics Data System (ADS)

Schieler, Brittany M.; Hale, Edward A.; Targett, Timothy E.

2014-12-01

Identifying factors that affect ingress of larval fishes from offshore spawning areas into estuarine nurseries is important to improve understanding of variability in recruitment of many coastal marine species. This study investigated the ingress of larval Atlantic croaker (Micropogonias undulatus), Atlantic menhaden (Brevoortia tyrannus), and summer flounder (Paralichthys dentatus) at Roosevelt Inlet, near the mouth of Delaware Bay, USA in relation to short-term wind events. Nightly abundances, from November 15 to December 15, 2010, were analyzed with alongshore and along-estuary wind components (direction and speed) using cross-correlation analysis to determine if winds affect larval ingress. Ingress of Atlantic croaker and summer flounder correlated with along-estuary winds, whereas Atlantic menhaden showed no significant correlations with either alongshore or along-estuary winds. Although along-estuary winds during this period were predominantly down-estuary, Atlantic croaker ingress was correlated with positive along-estuary winds (blowing up-estuary), with a three-day lag; and a particularly large ingress peak occurred following the largest up-estuary wind peak. Ingress of summer flounder was correlated with negative along-estuary winds (blowing down-estuary), with a two-day lag. These results suggest that species-specific vertical position in the water column influenced ingress into Delaware Bay. The lag results also suggest that ingressing Atlantic croaker and summer flounder may have a pooling stage outside the mouth of Delaware Bay.

36 CFR 14.7 - Right of ingress and egress to a primary right-of-way.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Right of ingress and egress to a primary right-of-way. 14.7 Section 14.7 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR RIGHTS-OF-WAY Nature of Interest § 14.7 Right of ingress and egress to...

36 CFR 14.7 - Right of ingress and egress to a primary right-of-way.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Right of ingress and egress to a primary right-of-way. 14.7 Section 14.7 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR RIGHTS-OF-WAY Nature of Interest § 14.7 Right of ingress and egress to...

Astronaut John Young ingresses Apollo spacecraft command module in training

NASA Image and Video Library

1968-07-05

S68-40875 (5 July 1968) --- Astronaut John W. Young, Apollo 7 backup command module pilot, ingresses Apollo Spacecraft 101 Command Module during simulated altitude runs at the Kennedy Space Center's Pad 34.

The Effect of Disturbances and Surrounding Air on the Droplet Impact Phenomena

NASA Astrophysics Data System (ADS)

Work, Andrew; Lian, Yongsheng; Sussman, Mark

2013-11-01

Supercooled Large Droplets (SLDs) represent an icing hazard in a number of areas, most obviously in aviation. SLDs pose a hazard above smaller supercooled droplets because they don't freeze completely on impact, and can spread or splash. Experiments have demonstrated that surrounding air plays an important role in the droplet impact phenomena: a low ambient pressure can suppress the droplet splashing. However, the effect of surrounding air on the droplet impact has not been adequately addressed. Numerical simulations are conducted to systematically investigate the interplay between the droplet and the surrounding air in the droplet splashing regime. Disturbances originating from the experimental droplet generator are also studied in the simulation. We investigate whether these disturbances are responsible for the fingering observed in experimentation. We compare the results of several perturbations on the droplet, as well as the effect of surface roughness. Simulations are conducted using the Moment of Fluid numerical method, and the grid features adaptive mesh refinement.

Reducing ingress of organic vapours into homes situated on contaminated land.

PubMed

Crump, D; Brown, V; Rowley, J; Squire, R

2004-04-01

The efficacy of current landfill gas and radon mitigation measures for the prevention of ingress of organic vapours was investigated by the study of four houses situated on contaminated land in North West England. The chemical present in the ground of greatest concern for health due to exposure to vapour in the indoor air was hexachlorobutadiene (HCBD) and the concentration of this compound was used to assess the effectiveness of the remedial measures. A two stage remediation was undertaken. For a house with a solid floor the top surface of the floor was sealed and then for the second stage a fan was used to pressurise the soil gas beneath the house. In a house with a suspended timber floor, extra air bricks were installed to increase ventilation of the floor void and then a fan to further increase air exchange in the void. HCBD in air was monitored by both pumped and diffusive sampling methods. Control houses were also monitored that were not subject to remediation. It is concluded that the remedial measures used for radon protection of a suspended floor have the potential to reduce indoor HCBD concentrations by about 80%, at least in downstairs rooms (where initial levels were highest). The two techniques used for properties with solid floors do not appear to be as effective, and no benefit at all was seen without making allowances for changes in concentration that occurred in the control house over the same period. Further work is required to test the efficacy of the techniques over a longer period and under different circumstances of type of contamination and building characteristics.

Age, growth and hatch dates of ingressing larvae and surviving juveniles of Atlantic menhaden Brevoortia tyrannus.

PubMed

Lozano, C; Houde, E D; Wingate, R L; Secor, D H

2012-10-01

Ages, growth and hatch dates of ingressing Brevoortia tyrannus larvae were determined in a 3 year sampling survey at the mouth of the Chesapeake Bay, U.S.A. To determine if otolith-aged cohorts had variable relative survival, hatch dates of summer-caught young-of-the-year (YOY) juveniles collected throughout the Chesapeake Bay were compared with hatch dates of ingressing larvae. Modal total length of ingressing larvae was similar among years: 28 mm in 2005-2006 and 2007-2008, and 30 mm in 2006-2007. Ages of ingressing larvae ranged from 9 to 96 days post hatch (dph); mean ages were similar among years, but significantly older in 2006-2007 (50 dph) than in 2005-2006 (44 dph) and 2007-2008 (46 dph). Larval growth rates differed among years. Earliest growth, when larvae were offshore (0-20 dph), was faster in 2006-2007 (0·62 mm day(-1)), than in 2005-2006 and 2007-2008 (0·55 mm day(-1) in these years). Subsequently, from 30 to 80 dph, growth was slowest in 2006-2007. Hatch dates of ingressing larvae occurred from September to March and 90% (2007-2008) to 98% (2006-2007) had hatched prior to 31 December. In contrast, most surviving YOY juvenile B. tyrannus had hatched in January to February, suggesting selective mortality of early-hatched individuals, apparently during the overwinter, larval to juvenile transition period. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

STS-131 crew during SSMTF Ingress/Egress Timeline training

NASA Image and Video Library

2010-02-10

JSC2010-E-024620 (10 Feb. 2010) --- NASA astronaut Stephanie Wilson, STS-131 mission specialist, participates in an ingress/egress timeline training session in a shuttle mock-up in the Space Vehicle Mock-up Facility at NASA's Johnson Space Center. United Space Alliance (USA) instructors David L. Williams (left) and Gary W. Kilgo assisted Wilson.

Moisture ingress prediction in polyisobutylene-based edge seal with molecular sieve desiccant

DOE PAGES

Kempe, Michael D.; Nobles, Dylan L.; Postak, Lori; ...

2017-10-26

Often photovoltaic modules are constructed with materials that are sensitive to water. This is most often the case with thin film technologies, including perovskite cells, where the active layers are a few microns thick and can be sensitive to moisture, liquid water or both. When moisture or liquid water can ingress, a small amount of water can lead to corrosion and depending on the resulting reactions, a larger local detrimental effect is possible. To prevent moisture from contacting photovoltaic components, impermeable frontsheets and backsheets are used with a polyisobutylene (PIB)-based edge seal material around the perimeter. Here, we evaluate themore » ability of a PIB-based edge seal using a molecular sieve desiccant to keep moisture out for the expected module lifetime. Moisture ingress is evaluated using test coupons where the edge seal is placed between 2 pieces of glass, one of which has a metallic calcium film on it, and monitoring the moisture ingress distance as a function of time. We expose samples to different temperature and humidity conditions to create permeation models useful for extrapolation to field use. This extrapolation indicates that this PIB material is capable of keeping moisture out of a module for the desired lifetime.« less

Moisture ingress prediction in polyisobutylene-based edge seal with molecular sieve desiccant

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

Kempe, Michael D.; Nobles, Dylan L.; Postak, Lori

Often photovoltaic modules are constructed with materials that are sensitive to water. This is most often the case with thin film technologies, including perovskite cells, where the active layers are a few microns thick and can be sensitive to moisture, liquid water or both. When moisture or liquid water can ingress, a small amount of water can lead to corrosion and depending on the resulting reactions, a larger local detrimental effect is possible. To prevent moisture from contacting photovoltaic components, impermeable frontsheets and backsheets are used with a polyisobutylene (PIB)-based edge seal material around the perimeter. Here, we evaluate themore » ability of a PIB-based edge seal using a molecular sieve desiccant to keep moisture out for the expected module lifetime. Moisture ingress is evaluated using test coupons where the edge seal is placed between 2 pieces of glass, one of which has a metallic calcium film on it, and monitoring the moisture ingress distance as a function of time. We expose samples to different temperature and humidity conditions to create permeation models useful for extrapolation to field use. This extrapolation indicates that this PIB material is capable of keeping moisture out of a module for the desired lifetime.« less

Measurement and Modeling of the Ability of Crack Fillers to Prevent Chloride Ingress into Mortar.

PubMed

Jones, Scott Z; Bentz, Dale P; Davis, Jeffrey M; Hussey, Daniel S; Jacobson, David L; Molloy, John L; Sieber, John R

2017-09-01

A common repair procedures applied to damaged concrete is to fill cracks with an organic polymer. This operation is performed to increase the service life of the concrete by removing a preferential pathway for the ingress of water, chlorides, and other deleterious species. To effectively fulfill its mission of preventing chloride ingress, the polymer must not only fully fill the macro-crack, but must also intrude the damage zone surrounding the crack perimeter. Here, the performance of two commonly employed crack fillers, one epoxy, and one methacrylate, are investigated using a combined experimental and computer modeling approach. Neutron tomography and microbeam X-ray fluorescence spectrometry (μXRF) measurements are employed on pre-cracked and chloride-exposed specimens to quantify the crack filling and chloride ingress limiting abilities, respectively, of the two polymers. A two-dimensional model of chloride transport is derived from a mass balance and solved by the finite element method. Crack images provided by μXRF are used to generate the input microstructure for the simulations. When chloride binding and a time-dependent mortar diffusivity are both included in the computer model, good agreement with the experimental results is obtained. Both crack fillers significantly reduce chloride ingress during the 21 d period of the present experiments; however, the epoxy itself contains approximately 4 % by mass chlorine. Leaching studies were performed assess the epoxy as a source of deleterious ions for initiating corrosion of the steel reinforcement in concrete structures.

A Human Factors Evaluation of a Methodology for Pressurized Crew Module Acceptability for Zero-Gravity Ingress of Spacecraft

NASA Technical Reports Server (NTRS)

Sanchez, Merri J.

2000-01-01

This project aimed to develop a methodology for evaluating performance and acceptability characteristics of the pressurized crew module volume suitability for zero-gravity (g) ingress of a spacecraft and to evaluate the operational acceptability of the NASA crew return vehicle (CRV) for zero-g ingress of astronaut crew, volume for crew tasks, and general crew module and seat layout. No standard or methodology has been established for evaluating volume acceptability in human spaceflight vehicles. Volume affects astronauts'ability to ingress and egress the vehicle, and to maneuver in and perform critical operational tasks inside the vehicle. Much research has been conducted on aircraft ingress, egress, and rescue in order to establish military and civil aircraft standards. However, due to the extremely limited number of human-rated spacecraft, this topic has been un-addressed. The NASA CRV was used for this study. The prototype vehicle can return a 7-member crew from the International Space Station in an emergency. The vehicle's internal arrangement must be designed to facilitate rapid zero-g ingress, zero-g maneuverability, ease of one-g egress and rescue, and ease of operational tasks in multiple acceleration environments. A full-scale crew module mockup was built and outfitted with representative adjustable seats, crew equipment, and a volumetrically equivalent hatch. Human factors testing was conducted in three acceleration environments using ground-based facilities and the KC-135 aircraft. Performance and acceptability measurements were collected. Data analysis was conducted using analysis of variance and nonparametric techniques.

Oxygen ingress study of 3D printed gaseous radiation detector enclosures

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

Steer, Christopher A.; Durose, Aaron

2015-07-01

As part of our ongoing studies into the potential application of 3D printing techniques to gaseous radiation detectors, we have studied the ability of 3D printed enclosures to resist environmental oxygen ingress. A set of cuboid and hexagonal prism shaped enclosures with wall thicknesses of 4 mm, 6 mm, 8 mm and 10 mm were designed and printed in nylon using a EOSINT P 730 Selective Laser Sintering 3D printer system These test enclosures provide a comparison of different environmental gas ingress for different 3D printing techniques. The rate of change of oxygen concentration was found to be linear, decreasingmore » as the wall thickness increases. It was also found that the hexagonal prism geometry produced a lower rate of change of oxygen concentration compared with the cuboid shaped enclosures. Possible reasons as to why these results were obtained are discussed The implications for the this study for deployable systems are also discussed (authors)« less

AIR PASSIVATION OF METAL HYDRIDE BEDS FOR WASTE DISPOSAL

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

Klein, J; R. H. Hsu, R

2007-07-02

Metal hydride beds offer compact, safe storage of tritium. After metal hydride beds have reached the end of their useful life, the beds will replaced with new beds and the old beds prepared for disposal. One acceptance criteria for hydride bed waste disposal is that the material inside the bed not be pyrophoric. To determine the pyrophoric nature of spent metal hydride beds, controlled air ingress tests were performed. A simple gas handling manifold fitted with pressure transducers and a calibrated volume were used to introduce controlled quantities of air into a metal hydride bed and the bed temperature risemore » monitored for reactivity with the air. A desorbed, 4.4 kg titanium prototype hydride storage vessel (HSV) produced a 4.4 C internal temperature rise upon the first air exposure cycle and a 0.1 C temperature rise upon a second air exposure. A total of 346 scc air was consumed by the bed (0.08 scc per gram Ti). A desorbed, 9.66 kg LaNi{sub 4.25}Al{sub 0.75} prototype storage bed experienced larger temperature rises over successive cycles of air ingress and evacuation. The cycles were performed over a period of days with the bed effectively passivated after the 12th cycle. Nine to ten STP-L of air reacted with the bed producing both oxidized metal and water.« less

Do predator-prey relationships on the river bed affect fine sediment ingress?

NASA Astrophysics Data System (ADS)

Mathers, Kate; Rice, Stephen; Wood, Paul

2016-04-01

Ecosystem engineers are organisms that alter their physical environment and thereby influence the flow of resources through ecosystems. In rivers, several ecosystem engineers are also important geomorphological agents that modify fluvial sediment dynamics. By altering channel morphology and bed material characteristics, such modifications can affect the availability of habitats for other organisms, with implications for ecosystem health and wider community composition. In this way geomorphological and ecological systems are intimately interconnected. This paper focuses on one element of this intricate abiotic-biotic coupling: the interaction between fine sediment ingress into the river bed and the predator-prey relationships of aquatic organisms living on and in the river bed. Signal crayfish (Pacifastacus leniusculus) have been shown to modify fine sediment fluxes in rivers, but their effect on fine sediment ingress into riverbeds remains unclear. Many macroinvertebrate taxa have adapted avoidance strategies to avoid predation by crayfish, with one example being the freshwater shrimp (Gammarus pulex) which relies on open interstitial spaces within subsurface sediments as a refuge from crayfish predation. Fine sedimentation that fills gravelly frameworks may preclude access to those spaces, therefore leaving freshwater shrimp susceptible to predation. Ex-situ experiments were conducted which sought to examine: i) if freshwater shrimps and signal crayfish, alone and in combination, influenced fine sediment infiltration rates; and ii) whether modifications to substratum composition, specifically the introduction of fine sediment, modified predator-prey interactions. The results demonstrate that crayfish are significant geomorphic agents and that fine sediment ingress rates were significantly enhanced in their presence compared to control conditions or the presence of only freshwater shrimps. The combination of both organisms (i.e. allowing the interaction between

Water ingress detection in honeycomb sandwich panels by passive infrared thermography using a high-resolution thermal imaging camera

NASA Astrophysics Data System (ADS)

Ibarra-Castanedo, C.; Brault, L.; Marcotte, F.; Genest, M.; Farley, V.; Maldague, X.

2012-06-01

Water ingress in honeycomb structures is of great concern for the civil and military aerospace industries. Pressure and temperature variations during take-off and landing produce considerable stress on aircraft structures, promoting moisture ingress (by diffusion through fibers or by direct ingress through voids, cracks or unsealed joints) into the core. The presence of water (or other fluids such as kerosene, hydraulic fluid and de-icing agents) in any of its forms (gas vapor, liquid or ice) promotes corrosion, cell breakage, and induce composite layer delaminations and skin disbonds. In this study, testing specimens were produced from unserviceable parts from military aircraft. In order to simulate atmospheric conditions during landing, selected core areas were filled with measured quantities of water and then frozen in a cold chamber. The specimens were then removed from the chamber and monitored for over 20 minutes as they warm up using a cooled high-resolution infrared camera. Results have shown that detection and quantification of water ingress on honeycomb sandwich structures by passive infrared thermography is possible using a HD mid-wave infrared cameras for volumes of water as low as 0.2 ml and from a distance as far as 20 m from the target.

Embryonic wound healing by apical contraction and ingression in Xenopus laevis.

PubMed

Davidson, Lance A; Ezin, Akouavi M; Keller, Ray

2002-11-01

We have characterized excisional wounds in the animal cap of early embryos of the frog Xenopus laevis and found that these wounds close accompanied by three distinct processes: (1) the assembly of an actin purse-string in the epithelial cells at the wound margin, (2) contraction and ingression of exposed deep cells, and (3) protrusive activity of epithelial cells at the margin. Microsurgical manipulation allowing fine control over the area and depth of the wound combined with videomicroscopy and confocal analysis enabled us to describe the kinematics and challenge the mechanics of the closing wound. Full closure typically occurs only when the deep, mesenchymal cell-layer of the ectoderm is left intact; in contrast, when deep cells are removed along with the superficial, epithelial cell-layer of the ectoderm, wounds do not close. Actin localizes to the superficial epithelial cell-layer at the wound margin immediately after wounding and forms a contiguous "purse-string" in those cells within 15 min. However, manipulation and closure kinematics of shaped wounds and microsurgical cuts made through the purse-string rule out a major force-generating role for the purse-string. Further analysis of the cell behaviors within the wound show that deep, mesenchymal cells contract their apical surfaces and ingress from the exposed surface. High resolution time-lapse sequences of cells at the leading edge of the wound show that these cells undergo protrusive activity only during the final phases of wound closure as the ectoderm reseals. We propose that assembly of the actin purse-string works to organize and maintain the epithelial sheet at the wound margin, that contraction and ingression of deep cells pulls the wound margins together, and that protrusive activity of epithelial cells at the wound margin reseals the ectoderm and re-establishes tissue integrity during wound healing in the Xenopus embryonic ectoderm. Copyright 2002 Wiley-Liss, Inc.

Vision-Aided Autonomous Landing and Ingress of Micro Aerial Vehicles

NASA Technical Reports Server (NTRS)

Brockers, Roland; Ma, Jeremy C.; Matthies, Larry H.; Bouffard, Patrick

2012-01-01

Micro aerial vehicles have limited sensor suites and computational power. For reconnaissance tasks and to conserve energy, these systems need the ability to autonomously land at vantage points or enter buildings (ingress). But for autonomous navigation, information is needed to identify and guide the vehicle to the target. Vision algorithms can provide egomotion estimation and target detection using input from cameras that are easy to include in miniature systems.

SMART PEBBLES : passive embeddable wireless sensors for chloride ingress monitoring in bridge decks.

DOT National Transportation Integrated Search

2003-06-01

SRI International has developed a wireless sensor for monitoring the level of chloride : ingress into concrete bridge decks. We call this device a Smart Pebble since it has : roughly the size and weight of a typical piece of the rock aggregate tha...

Oxygen Selective Membranes for Li-Air (O2) Batteries

PubMed Central

Crowther, Owen; Salomon, Mark

2012-01-01

Lithium-air (Li-air) batteries have a much higher theoretical energy density than conventional lithium batteries and other metal air batteries, so they are being developed for applications that require long life. Water vapor from air must be prevented from corroding the lithium (Li) metal negative electrode during discharge under ambient conditions, i.e., in humid air. One method of protecting the Li metal from corrosion is to use an oxygen selective membrane (OSM) that allows oxygen into the cell while stopping or slowing the ingress of water vapor. The desired properties and some potential materials for OSMs for Li-air batteries are discussed and the literature is reviewed. PMID:24958173

Inter and intra-estuary variability in ingress, condition and settlement of the American eel Anguilla rostrata: implications for estimating and understanding recruitment.

PubMed

Sullivan, M C; Wuenschel, M J; Able, K W

2009-06-01

The objective of this study was to quantify spatial and temporal variability of anguillid glass eel ingress within and between adjacent watersheds in order to help illuminate the mechanisms moderating annual recruitment. Because single fixed locations are often used to assess annual recruitment, the intra-annual dynamics of ingress across multiple sites often remains unresolved. To address this question, plankton nets and eel collectors were deployed weekly to synoptically quantify early stage Anguilla rostrata abundance at 12 sites across two New Jersey estuaries over an ingress season. Numbers of early-stage glass eels collected at the inlet mouths were moderately variable within and between estuaries over time and showed evidence for weak lunar phase and water temperature correlations. The relative condition of glass eels, although highly variable, declined significantly over the ingress season and indicated a tendency for lower condition A. rostrata to colonize sites in the lower estuary. Accumulations of glass eels and early-stage elvers retrieved from collectors (one to >1500 A. rostrata per collector) at lower estuary sites were highly variable over time, producing only weak correlations between estuaries. By way of contrast, development into late-stage elvers, coupled with the large-scale colonization of up-river sites, was highly synchronized between and within estuaries and contingent on water temperatures reaching c. 10-12 degrees C. Averaged over the ingress season, abundance estimates were remarkably consistent between paired sites across estuaries, indicating a low degree of interestuary variability. Within an estuary, however, abundance estimates varied considerably depending on location. These results and methodology have important implications for the planning and interpretation of early-stage anguillid eel surveys as well as the understanding of the dynamic nature of ingress and the spatial scales over which recruitment varies.

Evaluation of ATP measurements to detect microbial ingress by wastewater and surface water in drinking water.

PubMed

Vang, Óluva K; Corfitzen, Charlotte B; Smith, Christian; Albrechtsen, Hans-Jørgen

2014-11-01

Fast and reliable methods are required for monitoring of microbial drinking water quality in order to protect public health. Adenosine triphosphate (ATP) was investigated as a potential real-time parameter for detecting microbial ingress in drinking water contaminated with wastewater or surface water. To investigate the ability of the ATP assay in detecting different contamination types, the contaminant was diluted with non-chlorinated drinking water. Wastewater, diluted at 10(4) in drinking water, was detected with the ATP assay, as well as 10(2) to 10(3) times diluted surface water. To improve the performance of the ATP assay in detecting microbial ingress in drinking water, different approaches were investigated, i.e. quantifying microbial ATP or applying reagents of different sensitivities to reduce measurement variations; however, none of these approaches contributed significantly in this respect. Compared to traditional microbiological methods, the ATP assay could detect wastewater and surface water in drinking water to a higher degree than total direct counts (TDCs), while both heterotrophic plate counts (HPC 22 °C and HPC 37 °C) and Colilert-18 (Escherichia coli and coliforms) were more sensitive than the ATP measurements, though with much longer response times. Continuous sampling combined with ATP measurements displays definite monitoring potential for microbial drinking water quality, since microbial ingress in drinking water can be detected in real-time with ATP measurements. The ability of the ATP assay to detect microbial ingress is influenced by both the ATP load from the contaminant itself and the ATP concentration in the specific drinking water. Consequently, a low ATP concentration of the specific drinking water facilitates a better detection of a potential contamination of the water supply with the ATP assay. Copyright © 2014 Elsevier Ltd. All rights reserved.

Meteorological phenomena affecting the presence of solid particles suspended in the air during winter

NASA Astrophysics Data System (ADS)

Cariñanos, P.; Galán, C.; Alcázar, P.; Dominguez, E.

Winter is not traditionally considered to be a risky season for people who suffer from pollen allergies. However, increasing numbers of people are showing symptoms in winter. This prompted our investigation into the levels of solid material in the air, and some of the meteorological phenomena that allow their accumulation. This study showed a possible relationship between the phenomenon of thermal inversion, which occurs when very low temperatures, cloudless skies and atmospheric calms coincide, and an increase in the concentration of solid material in the atmosphere. Frequently, this situation is associated with other predictable phenomena such as fog, dew and frost. This may allow a warning system to be derived for urban pollution episodes. The effect caused by parameters such as wind and rainfall was also analysed. Solid material was differentiated into non-biological material from natural and non-natural sources (e.g. soot, dust, sand, diesel exhaust particles, partially burnt residues) and biological material. The latter mainly comprises pollen grains and fungal spores. Owing to its abundance and importance as a causal agent of winter allergies, Cupressaceae pollen was considered separately.

An analysis of injuries to front-end loader operators during ingress and egress.

PubMed

Nasarwanji, Mahiyar F; Pollard, Jonisha; Porter, William

2018-05-01

Slips, trips, and falls from mobile mining equipment have been documented for decades. However, little research has been conducted to determine the events precipitating these incidents during ingress or egress. This study examined slips, trips, and falls sustained during ingress or egress from front-end loaders to determine the frequencies of factors that may contribute to injuries. Non-fatal injuries, when getting on or off of front-end wheel loaders specifically, were identified, coded, and analyzed from the Mine Safety and Health Administration's accidents, injuries, and illnesses database. Overall trends, events that precipitated the injury, injuries sustained, contributing factors, location of the individual, and equipment characteristics were analyzed. More incidents occurred during egress (63%); and egress is believed to be more hazardous than ingress. Foot slips were the most common event that precipitated the incident and the leading cause of these was contaminants on the equipment. Misstep, loss of footing, and step on/in related incidents were more common during egress and are likely due to the operator's reduced visibility when descending a ladder facing the equipment, limiting their ability to detect hazards. Egress also makes an operator less capable of avoiding unsafe ground conditions as indicated by the significant number of step on/in injuries occurring on the ground during egress. Most of the front-end loaders associated with the incidents were found to have bottom rungs with flexible rails, which may also increase fall risk during egress due to inconsistent rung heights and lengthy transition areas from the ground, through the flexible-railed rungs, to the rungs with rigid rails. Recommendations are provided to reduce the risk for slips, trips, and falls from mobile mining equipment.

Reducing the ingress of urban noise through natural ventilation openings.

PubMed

Oldham, D J; de Salis, M H; Sharples, S

2004-01-01

For buildings in busy urban areas affected by high levels of road traffic noise the potential to use natural ventilation can be limited by excessive noise entering through ventilation openings. This paper is concerned with techniques to reduce noise ingress into naturally ventilated buildings while minimizing airflow path resistance. A combined experimental and theoretical approach to the interaction of airflow and sound transmission through ventilators for natural ventilation applications is described. A key element of the investigation has been the development of testing facilities capable of measuring the airflow and sound transmission losses for a range of ventilation noise control strategies. It is demonstrated that a combination of sound reduction mechanisms -- one covering low frequency sound and another covering high frequency sound -- is required to attenuate effectively noise from typical urban sources. A method is proposed for quantifying the acoustic performance of different strategies to enable comparisons and informed decisions to be made leading to the possibility of a design methodology for optimizing the ventilation and acoustic performance of different strategies. The need for employing techniques for combating low frequency sound in tandem with techniques for reducing high frequency sound in reducing the ingress of noise from urban sources such as road traffic to acceptable levels is demonstrated. A technique is proposed for enabling the acoustic and airflow performance of apertures for natural ventilation systems to be designed simultaneously.

Effects of light ingress through ventilation fan apertures on selected blood variables of male broilers

USDA-ARS?s Scientific Manuscript database

Increasing broiler house size and ventilation capacity have resulted in increased light ingress through ventilation system component apertures. The effective photoperiod for broilers may create local increases in light intensity, which may also impact broiler’ body homeostasis. The objective of this...

Comparison of 2 fluid ingress/egress systems for canine stifle arthroscopy using computed tomography.

PubMed

Warnock, Jennifer J; Nemanic, Sarah; O'Donnell, Matthew D; Wiest, Jason E

2014-11-01

To evaluate volume of extra-articular fluid egress and complications associated with 2 fluid ingress/egress techniques for stifle arthroscopy. Ex vivo study. Canine cadavers (n = 14). Four cadavers (8 stifles) were used to validate 3D computed tomographic (CT) methods to quantify stifle joint intra- and extra-articular volumes of iodinated contrast medium. Ten canine cadavers (20 stifles) had preoperative CT, followed by stifle arthroscopy using a 10% solution of iodinated contrast enhanced ingress fluid delivered by pressure bag (2PB) or by arthroscopic peristaltic pump (3FP). All 3FP limbs had an additional fluid egress portal placed by cannula and obturator. Arthroscopy was limited to 20 minutes/joint. The volume of the contrast medium egress into the soft tissues was measured on postoperative 3D CT reconstructed images. Mean percentage of total ingress fluids administered that remained in the joint and extra-articular tissues postoperatively was 8.8 ± 1.2% in 3FP and 33.2 ± 8% in 2PB (P = .014). Two 3FP joints had 4-5 mm egress obturator tracks on the proximal medial trochlear ridge. Two 2PB joints had severe joint collapse from extracapsular fluid precluding further examination. Intermittent visual blurring by joint fluid mixing or fat pad fragmentation/dissolution was noted in 2PB joints. A superior technique was not identified: 2PB had greater egress fluid tissue accumulation, whereas 3FP had better viewing of intra-articular structures with less tissue egress fluid accumulation; however, cartilage damage was induced with the egress obturator. © Copyright 2014 by The American College of Veterinary Surgeons.

Pharmaceutical container/closure integrity. II: The relationship between microbial ingress and helium leak rates in rubber-stoppered glass vials.

PubMed

Kirsch, L E; Nguyen, L; Moeckly, C S; Gerth, R

1997-01-01

Helium leak rate measurements were quantitatively correlated to the probability of microbial ingress for rubber-stoppered glass vials subjected to immersion challenge. Standard 10-mL tubing glass vials were modified by inserting micropipettes of various sizes (0.1 to 10 microns nominal diameter) into a side wall hole and securing them with epoxy. Butyl rubber closures and aluminum crimps were used to seal the vials. The test units were sealed in a helium-filled glove bag, then the absolute helium leak rates were determined. The test units were disassembled, filled with media, resealed, and autoclaved. The test units were thermally treated to eliminate airlocks within the micropipette lumen and establish a liquid path between microbial challenge media and the test units' contents. Microbial challenge was performed by immersing the test units in a 35 degrees C bath containing magnesium ion and 8 to 10 logs of viable P. diminuta and E. coli for 24 hours. The test units were then incubated at 35 degrees C for an additional 13 days. Microbial ingress was detected by turbidity and plating on blood agar. The elimination of airlocks was confirmed by the presence of magnesium ions in the vial contents by atomic absorption spectrometry. A total of 288 vials were subjected to microbial challenge testing. Those test units whose contents failed to show detectable magnesium ions were eliminated from further analysis. At large leak rates, the probability of microbial ingress approached 100% and at very low leak rates microbial ingress rates were 0%. A dramatic increase in microbial failure occurred in the leak rate region 10(-4.5) to 10(-3) std cc/sec, which roughly corresponded to leak diameters ranging from 0.4 to 2 microns. Below a leak rate of 10(-4.5) std cc/sec the microbial failure rate was < 10%. The critical leak rate in our studies, i.e. the value below which microbial ingress cannot occur because the leak is too small, was observed to be between 10(-5) and 10(-5.8) std

Non-destructive evaluation of water ingress in photovoltaic modules

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

Bora, Mihail; Kotovsky, Jack

Systems and techniques for non-destructive evaluation of water ingress in photovoltaic modules include and/or are configured to illuminate a photovoltaic module comprising a photovoltaic cell and an encapsulant with at least one beam of light having a wavelength in a range from about 1400 nm to about 2700 nm; capture one or more images of the illuminated photovoltaic module, each image relating to a water content of the photovoltaic module; and determine a water content of the photovoltaic module based on the one or more images. Systems preferably include one or more of a light source, a moving mirror, amore » focusing lens, a beam splitter, a stationary mirror, an objective lens and an imaging module.« less

Ingressive Speech Errors: A Service Evaluation of Speech-Sound Therapy in a Child Aged 4;6

ERIC Educational Resources Information Center

Hrastelj, Laura; Knight, Rachael-Anne

2017-01-01

Background: A pattern of ingressive substitutions for word-final sibilants can be identified in a small number of cases in child speech disorder, with growing evidence suggesting it is a phonological difficulty, despite the unusual surface form. Phonological difficulty implies a problem with the cognitive process of organizing speech into sound…

Experimental and modeling study of chloride ingress into concrete and reinforcement corrosion initiation

NASA Astrophysics Data System (ADS)

Yu, Hui

Effects of reinforcement and coarse aggregate on chloride ingression into concrete and reinforcement corrosion initiation have been studied with experimental and modeling (finite element method) analyses. Once specimens were fabricated and exposed to a chloride solution, various experimental techniques were employed to determine the effect of reinforcement and coarse aggregate on time-to-corrosion and chloride ingress and concentration at corrosion locations. Model analyses were performed to verify and explain the experimental results. Based upon the results, it was determined that unexpectedly higher chloride concentrations were present on the top of the rebar trace than that to the side at the same depth and an inverse concentration gradient (increasing [ Cl-] with increasing depth) occurred near the top of rebars. Also, coarse aggregate volume profile in close proximity to the rebar and spatial distribution of these aggregates, in conjunction with the physical obstruction afforded by reinforcement to chloride flow, complicates concrete sampling for Cl- intended to define the critical concentration of this species to initiate corrosion. Modeling analyses that considered cover thickness, chloride threshold concentration, reinforcement size and shape, and coarse aggregate type and percolation confirmed the experimental findings. The results, at least in part, account for the relatively wide spread in chloride corrosion threshold values reported in the literature and illustrate that more consistent chloride threshold concentrations can be acquired from mortar or paste specimens than from concrete ones.

Method Development for Container Closure Integrity Evaluation via Headspace Gas Ingress by Using Frequency Modulation Spectroscopy.

PubMed

Victor, Ken G; Levac, Lauren; Timmins, Michael; Veale, James

2017-01-01

USP <1207.1> Section 3.5 states that "A deterministic leak test method having the ability to detect leaks at the product's maximum allowable leakage limit is preferred when establishing the inherent integrity of a container-closure system." Ideally, container closure integrity of parenteral packaging would be evaluated by measuring a physical property that is sensitive to the presence of any package defect that breaches package integrity by increasing its leakage above its maximum allowable leakage limit. The primary goals of the work presented herein were to demonstrate the viability of the nondestructive, deterministic method known as laser-based gas headspace analysis for evaluating container closure integrity and to provide a physical model for predicting leak rates for a variety of container volumes, headspace conditions, and defect sizes. The results demonstrate that laser-based headspace analysis provides sensitive, accurate, and reproducible measurements of the gas ingress into glass vial-stopper package assemblies that are under either diffusive or effusive leak conditions. Two different types of positive controls were examined. First, laser-drilled micro-holes in thin metal disks that were crimped on top of 15R glass vials served as positive controls with a well-characterized defect geometry. For these, a strong correlation was observed between the measured ingress parameter and the size of the defect for both diffusive and effusive conditions. Second, laser-drilled holes in the wall of glass vials served as controls that more closely simulate real-world defects. Due to their complex defect geometries, their diffusive and effusive ingress parameters did not necessarily correlate; this is an important observation that has significant implications for standardizing the characterization of container defects. Regardless, laser-based headspace analysis could readily differentiate positive and negative controls for all leak conditions, and the results provide a

Sulfate-reducing bacteria lower sulfur-mediated pitting corrosion under conditions of oxygen ingress.

PubMed

Johnston, Shawna L; Voordouw, Gerrit

2012-08-21

The effect of oxygen ingress into sour water containing dissolved sulfide on the production of sulfur and polysulfide (S-PS) and associated iron corrosion was investigated. Biotic (active SRB present), abiotic (autoclaved SRB present), and chemical (no bacteria present) conditions were compared. Under biotic conditions formation of S-PS was only seen at a high ratio of oxygen to sulfide (R(OS)) of 1 to 2.4. General corrosion rates increased 10-fold to 0.10 mm/yr under these conditions. Under abiotic and chemical conditions S-PS formation increased over the entire range of R(OS) with general corrosion rates reaching 0.06 mm/yr. Although general corrosion rates were thus highest under biotic conditions, biotically corroded coupons showed much less pitting corrosion. Maximum pit depth increased to 40-80 μm with increasing R(OS) for coupons incubated for 1 month under abiotic or chemical conditions but not for biotically incubated coupons (10 μm). This appeared to be related to the properties and size of the sulfur formed, which was hydrophobic and in excess of 10 μm under chemical or abiotic conditions and hydrophilic and 0.5 to 1 μm under biotic conditions. Hence, perhaps contrary to expectation, SRB lowered pitting corrosion rates under conditions of oxygen ingress due to their ability to respire oxygen and produce a less aggressive form of sulfur. Microbial control, which is usually required in sour systems, may be counterproductive under these conditions.

Relationship between meteorological phenomena and air pollution in an urbanized and industrialized coastal area in northern France

NASA Astrophysics Data System (ADS)

Gengembre, Cyril; Zhang, Shouwen; Dieudonné, Elsa; Sokolov, Anton; Augustin, Patrick; Riffault, Véronique; Dusanter, Sébastien; Fourmentin, Marc; Delbarre, Hervé

2016-04-01

Impacts of global climate evolution are quite uncertain at regional and local scales, especially on air pollution. Air quality is associated with local atmospheric dynamics at a time scale shorter than a few weeks, while the climate change time scale is on the order of fifty years. To infer consequences of climate evolution on air pollution, it is necessary to fill the gap between these different scales. Another challenge is to understand the effect of global warming on the frequency of meteorological phenomena that influence air pollution. In this work, we classified meteorological events related to air pollution during a one-year long field campaign in Dunkirk (northern France). Owing to its coastal location under urban and industrial exposures, the Dunkirk agglomeration is an interesting area for studying gaseous and aerosols pollutants and their relationship with weather events such as sea breezes, fogs, storms and fronts. The air quality in the northern region of France is also greatly influenced by highly populated and industrialized cities along the coast of the North Sea, and by London and Paris agglomerations. During a field campaign, we used simultaneously a three-dimensional sonic anemometer and a weather station network, along with a scanning Doppler Lidar system to analyse the vertical structure of the atmosphere. An Aerosol Chemical Speciation Monitor enabled investigating the PM1 behaviour during the studied events. Air contaminants such as NOx (NO and NO2) were also measured by the regional pollution monitoring network ATMO Nord Pas-de-Calais. The events were identified by finding specific criteria from meteorological and turbulent parameters. Over a hundred cases of sea breezes, fog periods, stormy days and atmospheric front passages were investigated. Variations of turbulent parameters (vertical sensible heat flux and momentum flux) give estimations on the transport and the dispersal of pollutants. As the fluxes are weak during fogs, an increase

Biophysical processes leading to the ingress of temperate fish larvae into estuarine nursery areas: A review

NASA Astrophysics Data System (ADS)

Teodósio, Maria Alexandra; Paris, Claire B.; Wolanski, Eric; Morais, Pedro

2016-12-01

A series of complementary hypotheses have been proposed to explain the recruitment of marine and temperate pelagic fish larvae originated from pelagic eggs in coastal environments. In this review, we propose a new and complementary hypothesis describing the biophysical processes intervening in the recruitment of temperate fish larvae into estuaries. This new hypothesis, the Sense Acuity And Behavioral (SAAB) hypothesis, recognizes that recruitment is unlikely if the larvae drift passively with the water currents, and that successful recruitment requires the sense acuity of temperate fish larvae and their behavioral response to the estuarine cues present in coastal areas. We propose that temperate fish larvae use a hierarchy of sensory cues (odor, sound, visual and geomagnetic cues) to detect estuarine nursery areas and to aid during navigation towards these areas. The sensorial acuity increases along ontogeny, which coincides with increased swimming capabilities. The swimming strategies of post-flexion larvae differ from offshore areas to the tidal zone. In offshore areas, innate behavior might lead larvae towards the coast guided by a sun compass or by the earth's geomagnetic field. In areas under limited influence of estuarine plumes (either in energetic nearshore areas or offshore), post-flexion larvae display a searching swimming behavior for estuarine disconnected patches (infotaxis strategy). After finding an estuarine plume, larvae may swim along the increasing cue concentration to ingress into the estuary. Here, larvae exhibit a rheotaxis behavior and avoid displacement by longshore currents by keeping bearing during navigation. When larvae reach the vicinity of an estuary, merging diel rhythms with feeding and predator avoidance strategies with tidally induced movements is essential to increase their chances of estuarine ingress. A fish larva recruitment model developed for the Ria Formosa lagoon supports the general framework of the SAAB hypothesis. In

Investigation on Plasma Jet Flow Phenomena During DC Air Arc Motion in Bridge-Type Contacts

NASA Astrophysics Data System (ADS)

Zhai, Guofu; Bo, Kai; Chen, Mo; Zhou, Xue; Qiao, Xinlei

2016-05-01

Arc plasma jet flow in the air was investigated under a bridge-type contacts in a DC 270 V resistive circuit. We characterized the arc plasma jet flow appearance at different currents by using high-speed photography, and two polished contacts were used to search for the relationship between roughness and plasma jet flow. Then, to make the nature of arc plasma jet flow phenomena clear, a simplified model based on magnetohydrodynamic (MHD) theory was established and calculated. The simulated DC arc plasma was presented with the temperature distribution and the current density distribution. Furthermore, the calculated arc flow velocity field showed that the circular vortex was an embodiment of the arc plasma jet flow progress. The combined action of volume force and contact surface was the main reason of the arc jet flow. supported by National Natural Science Foundation of China (Nos. 51307030, 51277038)

36 CFR 14.5 - Nature of interest granted; settlement on right-of-way; rights of ingress and egress.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Nature of interest granted; settlement on right-of-way; rights of ingress and egress. 14.5 Section 14.5 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR RIGHTS-OF-WAY Nature of Interest § 14.5 Nature...

36 CFR 14.5 - Nature of interest granted; settlement on right-of-way; rights of ingress and egress.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Nature of interest granted; settlement on right-of-way; rights of ingress and egress. 14.5 Section 14.5 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR RIGHTS-OF-WAY Nature of Interest § 14.5 Nature...

36 CFR 14.5 - Nature of interest granted; settlement on right-of-way; rights of ingress and egress.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Nature of interest granted; settlement on right-of-way; rights of ingress and egress. 14.5 Section 14.5 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR RIGHTS-OF-WAY Nature of Interest § 14.5 Nature...

36 CFR 14.5 - Nature of interest granted; settlement on right-of-way; rights of ingress and egress.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Nature of interest granted; settlement on right-of-way; rights of ingress and egress. 14.5 Section 14.5 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR RIGHTS-OF-WAY Nature of Interest § 14.5 Nature...

36 CFR 14.5 - Nature of interest granted; settlement on right-of-way; rights of ingress and egress.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Nature of interest granted; settlement on right-of-way; rights of ingress and egress. 14.5 Section 14.5 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR RIGHTS-OF-WAY Nature of Interest § 14.5 Nature...

Lonchakov ingresses the Earth-facing port of the SM after arrival of the Soyuz TMA-13 Spacecraft

NASA Image and Video Library

2008-10-14

ISS017-E-019022 (14 Oct. 2008) --- Russian Federal Space Agency cosmonaut Yury Lonchakov, Expedition 18 flight engineer, ingresses the Earth-facing port of the International Space Station's Zarya module after arriving onboard the Soyuz TMA-13 spacecraft with NASA astronaut Michael Fincke, commander, and American spaceflight participant Richard Garriott (both out of frame). Hatches between the two spacecraft were opened at 4:55 a.m. (CDT).

An experimental investigation on the requirement of roof height and sill width for car ingress and egress.

PubMed

Causse, Julien; Wang, Xuguang; Denninger, Lisa

2012-01-01

This study aimed at experimentally investigating the influence of roof height and sill width on car ingress/egress movements. The first uncomfortable (Ht1) and the lowest acceptable (Ht2) roof heights were obtained from 26 participants of three different stature groups thanks to a multi-adjustable vehicle mock-up. Both Ht1 and Ht2 were affected neither by stature nor by vehicle type. Only a difference of 45 mm between Ht1 and Ht2 was observed. Tall volunteers more flexed the trunk and neck than short persons thanks to a larger space available around the seat when the head passing under the roof. The vehicle type had almost no effect on upper body posture. The roof height only affected neck flexion. The sill width mainly imposed a lateral translation. Results demonstrated that an appropriate roof height should be determined carefully. A small change of 45 mm in roof height may lead to an unacceptable situation. The present study experimentally investigated the effects of roof height and sill width on car ingress and egress movements. Short females required almost the same roof height as tall males due to smaller space around the seat. The results would help to optimise car dimensions for improving car accessibility.

The Transit Ingress and the Tilted Orbit of the Extraordinarily Eccentric Exoplanet HD 80606b

NASA Technical Reports Server (NTRS)

Winn, Joshua N.; Howard, Andrew W.; Johnson, John A.; Marcy, Geoffrey W.; Gazak, J. Zachary; Starkey, Donn; Ford, Eric B.; Colon, Knicole D.; Reyes, Francisco; Nortmann, Lisa;

Perfluorocarbon Tracer Experiments on a 2 km Scale in Manchester Showing Ingress of Pollutants into a Building

NASA Astrophysics Data System (ADS)

Matthews, James; Wright, Matthew; Bacak, Asan; Silva, Hugo; Priestley, Michael; Martin, Damien; Percival, Carl; Shallcross, Dudley

2016-04-01

Cyclic perfluorocarbons (PFCs) have been used to measure the passage of air in urban and rural settings as they are chemically inert, non-toxic and have low background concentrations. The use of pre-concentrators and chemical ionisation gas chromatography enables concentrations of a few parts per quadrillion (ppq) to be measured in bag samples. Three PFC tracers were used in Manchester, UK in the summer of 2015 to map airflow in the city and ingress into buildings: perfluomethylcyclohexane (PMCH), perfluoro-2-4-dimethylcyclohexane (mPDMCH) and perfluoro-2-methyl-3-ethylpentene (PMEP). A known quantity of each PFC was released for 15 minutes from steel canisters using pre-prepared PFC mixtures. Release points were chosen to be upwind of the central sampling location (Simon Building, University of Manchester) and varied in distance up to 2.2 km. Six releases using one or three tracers in different configurations and under different conditions were undertaken in the summer. Three further experiments were conducted in the Autumn, to more closely investigate the rate of ingress and decay of tracer indoors. In each experiment, 10 litre samples were made over 30 minutes into Tedlar bags, starting at the same time the as PFC release. Samples were taken in 11 locations chosen from 15 identified areas including three in public parks, three outside within the University of Manchester area, seven inside and five outside of the Simon building and two outside a building nearby. For building measurements, receptors were placed inside the buildings on different floors; outside measurements were achieved through a sample line out of the window. Three of the sample positions inside the Simon building were paired with samplers outside to allow indoor-outdoor comparisons. PFC concentrations varied depending on location and height. The highest measured concentrations occurred when the tracer was released at sunrise; up to 330 ppq above background (11 ppq) of PMCH was measured at the 6

Discomfort Evaluation of Truck Ingress/Egress Motions Based on Biomechanical Analysis

PubMed Central

Choi, Nam-Chul; Lee, Sang Hun

2015-01-01

This paper presents a quantitative discomfort evaluation method based on biomechanical analysis results for human body movement, as well as its application to an assessment of the discomfort for truck ingress and egress. In this study, the motions of a human subject entering and exiting truck cabins with different types, numbers, and heights of footsteps were first measured using an optical motion capture system and load sensors. Next, the maximum voluntary contraction (MVC) ratios of the muscles were calculated through a biomechanical analysis of the musculoskeletal human model for the captured motion. Finally, the objective discomfort was evaluated using the proposed discomfort model based on the MVC ratios. To validate this new discomfort assessment method, human subject experiments were performed to investigate the subjective discomfort levels through a questionnaire for comparison with the objective discomfort levels. The validation results showed that the correlation between the objective and subjective discomforts was significant and could be described by a linear regression model. PMID:26067194

Cardiomyocyte binucleation is associated with aberrant mitotic microtubule distribution, mislocalization of RhoA and IQGAP3, as well as defective actomyosin ring anchorage and cleavage furrow ingression.

PubMed

Leone, Marina; Musa, Gentian; Engel, Felix Benedikt

2018-03-07

After birth mammalian cardiomyocytes initiate a last cell cycle which results in binucleation due to cytokinesis failure. Despite its importance for cardiac regenerative therapies, this process is poorly understood. Here, we aimed at a better understanding of the difference between cardiomyocyte proliferation and binucleation, and providing a new tool to distinguish these two processes. Monitoring of cell division by time-lapse imaging revealed that rat cardiomyocyte binucleation stems from a failure to properly ingress the cleavage furrow. Astral microtubule required for actomyosin ring anchorage and thus furrow ingression were not symmetrically distributed at the periphery of the equatorial region during anaphase in binucleating cardiomyocytes. Consequently, RhoA, the master regulator of actomyosin ring formation and constriction, non-muscle myosin IIB, a central component of the actomyosin ring, as well as IQGAP3 were abnormally localized during cytokinesis. In agreement with improper furrow ingression, binucleation in vitro as well as in vivo was associated with a failure of RhoA as well as IQGAP3 to localize to the stembody of the midbody. Taken together, these results indicate that naturally occurring cytokinesis failure in primary cardiomyocytes is due to an aberrant mitotic microtubule apparatus resulting in inefficient anchorage of the actomyosin ring to the plasma cell membrane. Thus, cardiomyocyte binucleation and division can be discriminated by the analysis of RhoA as well as IQGAP3 localization.

Demonstrations of Magnetic Phenomena: Measuring the Air Permeability Using Tablets

ERIC Educational Resources Information Center

Lara, V. O. M.; Amaral, D. F.; Faria, D.; Vieira, L. P.

2014-01-01

We use a tablet to experimentally determine the dependencies of the magnetic field (B) on the electrical current and the axial distance from a coil (z). Our data shows good precision on the inverse cubic dependence of the magnetic field on the axial distance, B?z[superscript -3]. We obtain the value of air permeability µ[subscript air] with good…

Non-destructive vacuum decay method for pre-filled syringe closure integrity testing compared with dye ingress testing and high-voltage leak detection.

PubMed

Simonetti, Andrea; Amari, Filippo

2015-01-01

solution, preventing possible prefilled syringe plunger movement during container closure integrity testing execution, is presented as well. The growing need to meet sterile drug products' regulatory, quality, and safety expectations has progressively driven new developments and improvements both in container closure integrity testing methods and in the respective equipment, over the last years. Indeed, container closure integrity testing establishes the container closure system capability to provide required protection to the drug product and to demonstrate maintenance of product sterility over its shelf life. This article describes the development of four container closure integrity testing approaches for the evaluation of glass prefilled syringe closure integrity, including two destructive (pharmacopoeial and Novartis specific dye ingress test) and two non-destructive (vacuum decay and high-voltage leak detection) methods. The important finding from the validation of comparative studies was that the vacuum decay method resulted in the most effective, reliable and repeatable detection of defective samples, whether the defect was exposed to sterile water, to drug product, or to air. Complete sets of known defects were created for this purpose (5 μm, 10 μm, 20 μm certified leakages by laser drilled holes and capillary tubes). All investigations and studies were conducted at Bonfiglioli Engineering S.r.l. (Vigarano Pieve, Ferrara, Italy) and at Novartis Vaccines (Sovicille, Siena, Italy). © PDA, Inc. 2015.

Some perspective decisions for the regeneration system equipment of the thermal and nuclear power plants decreasing the probability of water ingress into the turbine and rotor acceleration by return steam flow

NASA Astrophysics Data System (ADS)

Trifonov, N. N.; Svyatkin, F. A.; Sintsova, T. G.; Ukhanova, M. G.; Yesin, S. B.; Nikolayenkova, E. K.; Yurchenko, A. Yu.; Grigorieva, E. B.

2016-03-01

The regeneration system heaters are one of the sources of possible ingress of the water into the turbine. The water penetrates into the turbine either at the heaters overflow or with the return flow of steam generated when the water being in the heater boils up in the dynamic operation modes or at deenergization of the power-generating unit. The return flow of steam and water is dangerous to the turbine blades and can result in the rotor acceleration. The known protective devices used to prevent the overflow of the low-pressure and high-pressure heaters (LPH and HPH), of the horizontal and vertical heaters of heating-system water (HWH and VWH), as well as of the deaerators and low-pressure mixing heaters (LPMH) were considered. The main protective methods of the steam and water return flows supplied by the heaters in dynamic operation modes or at deenergization of the power-generating unit are described. Previous operating experience shows that the available protections do not fully prevent water ingress into the turbine and the rotor acceleration and, therefore, the development of measures to decrease the possibility of ingress of the water into the turbine is an actual problem. The measures allowing eliminating or reducing the water mass in the heaters are expounded; some of them were designed by the specialists of OAO Polzunov Scientific and Development Association on Research and Design of Power Equipment (NPO CKTI) and are efficiently introduced at heat power plants and nuclear power plants. The suggested technical solutions allow reducing the possibility of the water ingress into the turbine and rotor acceleration by return steam flow in the dynamic operation modes or in the case of power generating unit deenergization. Some of these solutions have been tested in experimental-industrial exploitation and can be used in industry.

Leak testing in parenteral packaging: establishment of direct correlation between helium leak rate measurements and microbial ingress for two different leak types.

PubMed

Morrical, Bradley D; Goverde, Marcel; Grausse, Jean; Gerwig, Tanja; Vorgrimler, Lothar; Morgen, Rachel; Büttiker, Jean-Pierre

2007-01-01

A direct test method using helium leak detection was developed to determine microbial ingress in parenteral vial/rubber closure systems. The purpose of this study was to establish a direct correlation between the helium leak rate and the presence of ingress when vials were submersed under pressure in a broth of bacteria. Results were obtained for two different types of leaks: microholes that have been laser-drilled into thin metal plates, and thin copper wire that was placed between the rubber closure and the glass vial's sealing surface. The results from the microholes showed that the helium leak rate was a function of the square of the hole diameter and fit well with theoretical calculations. The relationship with the wire gave a far more complex dependence and was not modeled theoretically. Comparison with the microbial challenge showed that for microholes a lower size limit was found to be 2 microm with a corresponding leak rate of 1.4 x 10(-3) mbarl/s. For the fine wire experiment the lower limit was 15-microm wire and a corresponding leak rate of 1.3 x 10(-5) mbarl/s. From these tests a safe, lower limit, leak rate was established.

Paranormal phenomena

NASA Astrophysics Data System (ADS)

Gaina, Alex

1996-08-01

Critical analysis is given of some paranormal phenomena events (UFO, healers, psychokinesis (telekinesis))reported in Moldova. It is argued that correct analysis of paranormal phenomena should be made in the framework of electromagnetism.

ESM of ionic and electrochemical phenomena on the nanoscale

DOE PAGES

Kalinin, Sergei V.; Kumar, Amit; Balke, Nina; ...

2011-01-01

Operation of energy storage and conversion devices is ultimately controlled by series of intertwined ionic and electronic transport processes and electrochemical reactions at surfaces and interfaces, strongly mediated by strain and mechanical processes. In a typical fuel cell, these include chemical species transport in porous cathode and anode materials, gas-solid electrochemical reactions at grains and triple-phase boundaries (TPBs), ionic and electronic flows in multicomponent electrodes, and chemical and electronic potential drops at internal interfaces in electrodes and electrolytes. Furthermore, all these phenomena are sensitively affected by the microstructure of materials from device level to the atomic scales. Similar spectrum ofmore » length scales and phenomena underpin operation of other energy systems including primary and secondary batteries, as well as hybrid systems such flow and metal-air/water batteries.« less

Impact of measurable physical phenomena on contact thermal comfort

NASA Astrophysics Data System (ADS)

Fojtlín, Miloš; Pokorný, Jan; Fišer, Jan; Toma, Róbert; Tuhovčák, Ján

Cabin HVAC (Heating Ventilation and Air-conditioning) systems have become an essential part of personal vehicles as demands for comfortable transport are still rising. In fact, 85 % of the car trips in Europe are shorter than 18 km and last only up to 30 minutes. Under such conditions, the HVAC unit cannot often ensure desired cabin environment and passengers are prone to experience thermal stress. For this reason, additional comfort systems, such as heated or ventilated seats, are available on the market. However, there is no straightforward method to evaluate thermal comfort at the contact surfaces nowadays. The aim of this work is to summarise information about heated and ventilated seats. These technologies use electrical heating and fan driven air to contact area in order to achieve enhanced comfort. It is also expected, that such measures may contribute to lower energy consumption. Yet, in real conditions it is almost impossible to measure the airflow through the ventilated seat directly. Therefore, there is a need for an approach that would correlate measurable physical phenomena with thermal comfort. For this reason, a method that exploits a measurement of temperatures and humidity at the contact area is proposed. Preliminary results that correlate comfort with measurable physical phenomena are demonstrated.

Seasonality of alcohol-related phenomena in Estonia.

PubMed

Silm, Siiri; Ahas, Rein

2005-03-01

We studied alcohol consumption and its consequences as a seasonal phenomenon in Estonia and analysed the social and environmental factors that may cause its seasonal rhythm. There are two important questions when researching the seasonality of human activities: (1) whether it is caused by natural or social factors, and (2) whether the impact of the factors is direct or indirect. Often the seasonality of social phenomena is caused by social factors, but the triggering mechanisms are related to environmental factors like temperature, precipitation, and radiation via the circannual calendar. The indicators of alcohol consumption in the current paper are grouped as: (1) pre-consumption phenomena, i.e. production, tax and excise, sales (beer, wine and vodka are analysed separately), and (2) post-consumption phenomena, i.e. alcohol-related crime and traffic accidents and the number of people detained in lockups and admitted to alcohol treatment clinics. In addition, seasonal variability in the amount of alcohol advertising has been studied, and a survey has been carried out among 87 students of Tartu University. The analysis shows that different phenomena related to alcohol have a clear seasonal rhythm in Estonia. The peak period of phenomena related to beer is in the summer, from June to August and the low point is during the first months of the year. Beer consumption correlates well with air temperature. The consumption of vodka increases sharply at the end of the year and in June; the production of vodka does not have a significant correlation with negative temperatures. The consumption of wine increases during summer and in December. The consequences of alcohol consumption, expressed as the rate of traffic accidents or the frequency of medical treatment, also show seasonal variability. Seasonal variability of alcohol consumption in Estonia is influenced by natural factors (temperature, humidity, etc.) and by social factors (celebrations, vacations, etc.). However

Seasonality of alcohol-related phenomena in Estonia

NASA Astrophysics Data System (ADS)

Silm, Siiri; Ahas, Rein

2005-03-01

We studied alcohol consumption and its consequences as a seasonal phenomenon in Estonia and analysed the social and environmental factors that may cause its seasonal rhythm. There are two important questions when researching the seasonality of human activities: (1) whether it is caused by natural or social factors, and (2) whether the impact of the factors is direct or indirect. Often the seasonality of social phenomena is caused by social factors, but the triggering mechanisms are related to environmental factors like temperature, precipitation, and radiation via the circannual calendar. The indicators of alcohol consumption in the current paper are grouped as: (1) pre-consumption phenomena, i.e. production, tax and excise, sales (beer, wine and vodka are analysed separately), and (2) post-consumption phenomena, i.e. alcohol-related crime and traffic accidents and the number of people detained in lockups and admitted to alcohol treatment clinics. In addition, seasonal variability in the amount of alcohol advertising has been studied, and a survey has been carried out among 87 students of Tartu University. The analysis shows that different phenomena related to alcohol have a clear seasonal rhythm in Estonia. The peak period of phenomena related to beer is in the summer, from June to August and the low point is during the first months of the year. Beer consumption correlates well with air temperature. The consumption of vodka increases sharply at the end of the year and in June; the production of vodka does not have a significant correlation with negative temperatures. The consumption of wine increases during summer and in December. The consequences of alcohol consumption, expressed as the rate of traffic accidents or the frequency of medical treatment, also show seasonal variability. Seasonal variability of alcohol consumption in Estonia is influenced by natural factors (temperature, humidity, etc.) and by social factors (celebrations, vacations, etc.). However

Recent Applications of Higher-Order Spectral Analysis to Nonlinear Aeroelastic Phenomena

NASA Technical Reports Server (NTRS)

Silva, Walter A.; Hajj, Muhammad R.; Dunn, Shane; Strganac, Thomas W.; Powers, Edward J.; Stearman, Ronald

2005-01-01

Recent applications of higher-order spectral (HOS) methods to nonlinear aeroelastic phenomena are presented. Applications include the analysis of data from a simulated nonlinear pitch and plunge apparatus and from F-18 flight flutter tests. A MATLAB model of the Texas A&MUniversity s Nonlinear Aeroelastic Testbed Apparatus (NATA) is used to generate aeroelastic transients at various conditions including limit cycle oscillations (LCO). The Gaussian or non-Gaussian nature of the transients is investigated, related to HOS methods, and used to identify levels of increasing nonlinear aeroelastic response. Royal Australian Air Force (RAAF) F/A-18 flight flutter test data is presented and analyzed. The data includes high-quality measurements of forced responses and LCO phenomena. Standard power spectral density (PSD) techniques and HOS methods are applied to the data and presented. The goal of this research is to develop methods that can identify the onset of nonlinear aeroelastic phenomena, such as LCO, during flutter testing.

Ultrafast Phenomena XIV

NASA Astrophysics Data System (ADS)

Kobayashi, Takayoshi; Okada, Tadashi; Kobayashi, Tetsuro; Nelson, Keith A.; de Silvestri, Sandro

Ultrafast Phenomena XIV presents the latest advances in ultrafast science, including ultrafast laser and measurement technology as well as studies of ultrafast phenomena. Pico-, femto-, and atosecond processes relevant in physics, chemistry, biology, and engineering are presented. Ultrafast technology is now having a profound impact within a wide range of applications, among them imaging, material diagnostics, and transformation and high-speed optoelectronics . This book summarizes results presented at the 14th Ultrafast Phenomena Conference and reviews the state of the art in this important and rapidly advancing field.

Impact of Air Entraining Method on the Resistance of Concrete to Internal Cracking

NASA Astrophysics Data System (ADS)

Wawrzeńczyk, Jerzy; Molendowska, Agnieszka

2017-10-01

This paper presents the test results of air entrained concrete mixtures made at a constant W/C ratio of 0.44. Three different air entraining agents were used: polymer microspheres, glass microspheres and a conventional air entraining admixture. The aim of this study was to compare the effectiveness of the air entraining methods. Concrete mixture tests were performed for consistency (slump test), density and, in the case of AEA series, air content by pressure method. Hardened concrete tests were performed for compressive strength, water absorption, resistance to chloride ingress, and freeze-thaw durability - resistance to internal cracking tests were conducted in accordance with PN-88/B-06250 on cube specimens and with the modified ASTM C666 A test method on beam specimens; porosity characteristics (A, A300, \\bar L) were determined to PN-EN 480-11:1998. No significant mass and length changes were recorded for the concrete air entrained with the conventional methods or with polymer microspheres. The results indicate that polymer microspheres are a very good alternative to traditional air entraining methods for concrete, providing effective air entrainment and protection from freezing and thawing. The glass microsphere-based concretes showed insufficient freeze-thaw resistance. The test results indicate that both the conventional methods (AEA) and the air entrainment by polymer microspheres are effective air entraining methods. It has to be noted that in the case of the use of polymer microspheres, a comparable value of \\bar L and a very good freeze-thaw resistance can be achieved at a noticeably lower air and micropore contents and at lower strength loss.

Phenomena of Pneumatic Tire Hydroplaning

NASA Technical Reports Server (NTRS)

Dreher, R. C.; Horne, W. B.

1963-01-01

Recent research on pneumatic tire hydroplaning has been collected and summarized with the aim of describing what is presently known about the phenomena of tire hydroplaning. A physical description of tire hydroplaning is given along with formulae for estimating the ground speed at which it occurs. Eight manifestations of tire hydroplaning which have been experimentally observed are presented and discussed. These manifestations are: detachment of tire footprint, hydrodynamic ground pressure, spin-down of wheel, suppression of tire bow wave, scouring action of escaping fluid in tire-ground footprint region, peaking of fluid displacement drag, loss in braking traction, and loss of tire directional stability. The vehicle, pavement, tire, and fluid parameters of importance to tire hydroplaning are listed and described. Finally, the hazards of tire hydroplaning to ground and air-vehicle-ground performance are listed, and procedures are given to minimize these effects.

Shock Tunnel Studies of Scramjet Phenomena

NASA Technical Reports Server (NTRS)

Stalker, R. J.

1996-01-01

Work focussed on a large number of preliminary studies of supersonic combustion in a simple combustion duct - thrust nozzle combination, investigating effects of Mach number, equivalence ratio, combustor divergence, fuel injecting angle and other parameters with an influence on the combustion process. This phase lasted for some three or four years, during which strongest emphasis was placed on responding to the request for preliminary experimental information on high enthalpy effects, to support the technology maturation activities of the NASP program. As the need for preliminary data became less urgent, it was possible to conduct more systematic studies of high enthalpy combustion phenomena, and to initiate other projects aimed at improving the facilities and instrumentation used for studying scramjet phenomena at high enthalpies. The combustion studies were particularly directed towards hypersonic combustion, and to the effects of injecting fuel along the combustion chamber wall. A substantial effort was directed towards a study of the effect of scale on the supersonic combustion process. The influence of wave phenomena (both compression waves and expansion waves) on the realization of thrust from a supersonic combustion process was also investigated. The effect of chemical kinetics was looked into, particularly as it affected the composition of the test flow provided by a ground facility. The effect of injection of the fuel through wall orifices was compared with injection from a strut spanning the stream, and the effect of heating the fuel prior to injection was investigated. Studies of fuel-air mixing by shock impingement were also done, as well as mass spectrometer surveys of a combustion wake. The use of hypersonic nozzles with an expansion tube was investigated. A new method was developed for measuring the forces acting of a model in less than one millisecond. Also included in this report are listings of published journal papers and conference presentations.

Nursing phenomena in inpatient psychiatry.

PubMed

Frauenfelder, F; Müller-Staub, M; Needham, I; Van Achterberg, T

2011-04-01

Little is known about the question if the nursing diagnosis classification of North American Nursing Association-International (NANDA-I) describes the adult inpatient psychiatric nursing care. The present study aimed to identify nursing phenomena mentioned in journal articles about the psychiatric inpatient nursing care and to compare these phenomena with the labels and the definitions of the nursing diagnoses to elucidate how well this classification covers these phenomena. A search of journal articles took place in the databases MedLine, PsychInfo, Cochrane and CINAHL. A qualitative content analysis approach was used to identify nursing phenomena in the articles. Various phenomena were found in the articles. The study demonstrated that NANDA-I describes essential phenomena for the adult inpatient psychiatry on the level of labels and definitions. However, some apparently important nursing phenomena are not covered by the labels or definitions of NANDA-I. Other phenomena are assigned as defining characteristics or as related factors to construct nursing diagnoses. The further development of the classification NANDA-I will strengthen the application in the daily work of psychiatric nurses and enhance the quality of nursing care in the inpatient setting. © 2010 Blackwell Publishing.

Phenomena Associated with EIT Waves

NASA Technical Reports Server (NTRS)

Thompson, B. J.; Biesecker, D. A.; Gopalswamy, N.; Fisher, Richard R. (Technical Monitor)

2002-01-01

We discuss phenomena associated with 'EIT Wave' transients. These phenomena include coronal mass ejections, flares, EUV/SXR dimmings, chromospheric waves, Moreton waves, solar energetic particle events, energetic electron events, and radio signatures. Although the occurrence of many phenomena correlate with the appearance of EIT waves, it is difficult to infer which associations are causal. The presentation will include a discussion of correlation surveys of these phenomena.

Phenomena Associated With EIT Waves

NASA Technical Reports Server (NTRS)

Thompson, B. J.; Biesecker, D. A.; Gopalswamy, N.

2003-01-01

We discuss phenomena associated with "EIT Wave" transients. These phenomena include coronal mass ejections, flares, EUV/SXR dimmings, chromospheric waves, Moreton waves, solar energetic particle events, energetic electron events, and radio signatures. Although the occurrence of many phenomena correlate with the appearance of EIT waves, it is difficult to mfer which associations are causal. The presentation will include a discussion of correlation surveys of these phenomena.

Luminous phenomena and electromagnetic VHF wave emission originated from earthquake-related radon exhalation

NASA Astrophysics Data System (ADS)

Seki, A.; Tobo, I.; Omori, Y.; Muto, J.; Nagahama, H.

2013-12-01

Anomalous luminous phenomena and electromagnetic wave emission before or during earthquakes have been reported (e.g., the 1965 Matsushiro earthquake swarm). However, their mechanism is still unsolved, in spite of many models for these phenomena. Here, we propose a new model about luminous phenomena and electromagnetic wave emission during earthquake by focusing on atmospheric radon (Rn-222) and its daughter nuclides (Po-218 and Po-214). Rn-222, Po-218 and Po-214 are alpha emitters, and these alpha particles ionize atmospheric molecules. A light emission phenomenon, called 'the air luminescence', is caused by de-excitation of the ionized molecules of atmospheric nitrogen due to electron impact ionization from alpha particles. The de-excitation is from the second positive system of neutral nitrogen molecules and the first negative system of nitrogen molecule ion. Wavelengths of lights by these transitions include the visible light wavelength. So based on this mechanism, we proposed a new luminous phenomenon model before or during earthquake: 1. The concentration of atmospheric radon and its daughter nuclides increase anomalously before or during earthquakes, 2. Nitrogen molecules and their ions are excited by alpha particles emitted from Rn-222, Po-218 and Po-214, and air luminescence is generated by their de-excitation. Similarly, electromagnetic VHF wave emission can be explained by ionizing effect of radon and its daughter nuclides. Boyarchuk et al. (2005) proposed a model that electromagnetic VHF wave emission is originated when excited state of neutral clusters changes. Radon gas ionizes atmosphere and forms positively and negatively charged heavy particles. The process of ion hydration in ordinary air can be determined by the formation of complex chemically active structures of the various types of ion radicals. As a result of the association of such hydration radical ions, a neutral cluster, which is dipole quasi-molecules, is formed. A neutral cluster

Damage Assessment of Structures an Air Force Office of Scientific Research Structural Mechanics Perspective

DTIC Science & Technology

2007-07-01

air turbulence and structural vibration , etc. Flexible load- bearing skins and reconfigurable support structures for smart and adaptive morphing...phenomena for flapping-wing micro air vehicles, the prevention and control of nonlinear and aeroelastic phenomena, energy harvesting from environmental...Embedded Ultrasonic NDE is a research project aimed at studying the Lamb wave interaction between piezoelectric wafer active sensors (PWAS) and the host

Air oxidation of Zircaloy-4 in the 600-1000 °C temperature range: Modeling for ASTEC code application

NASA Astrophysics Data System (ADS)

Coindreau, O.; Duriez, C.; Ederli, S.

2010-10-01

Progress in the treatment of air oxidation of zirconium in severe accident (SA) codes are required for a reliable analysis of severe accidents involving air ingress. Air oxidation of zirconium can actually lead to accelerated core degradation and increased fission product release, especially for the highly-radiotoxic ruthenium. This paper presents a model to simulate air oxidation kinetics of Zircaloy-4 in the 600-1000 °C temperature range. It is based on available experimental data, including separate-effect experiments performed at IRSN and at Forschungszentrum Karlsruhe. The kinetic transition, named "breakaway", from a diffusion-controlled regime to an accelerated oxidation is taken into account in the modeling via a critical mass gain parameter. The progressive propagation of the locally initiated breakaway is modeled by a linear increase in oxidation rate with time. Finally, when breakaway propagation is completed, the oxidation rate stabilizes and the kinetics is modeled by a linear law. This new modeling is integrated in the severe accident code ASTEC, jointly developed by IRSN and GRS. Model predictions and experimental data from thermogravimetric results show good agreement for different air flow rates and for slow temperature transient conditions.

Effects of implant design parameters on fluid convection, potentiating third-body debris ingress into the bearing surface during THA impingement/subluxation.

PubMed

Lundberg, Hannah J; Pedersen, Douglas R; Baer, Thomas E; Muste, Marian; Callaghan, John J; Brown, Thomas D

2007-01-01

Aseptic loosening from polyethylene wear debris is the leading cause of failure for metal-on-polyethylene total hip implants. Third-body debris ingress to the bearing space results in femoral head roughening and acceleration of polyethylene wear. How third-body particles manage to enter the bearing space between the closely conforming articulating surfaces of the joint is not well understood. We hypothesize that one such mechanism is from convective fluid transport during subluxation of the total hip joint. To test this hypothesis, a three-dimensional (3D) computational fluid dynamics (CFD) model was developed and validated, to quantify fluid ingress into the bearing space during a leg-cross subluxation event. The results indicated that extra-articular joint fluid could be drawn nearly to the pole of the cup with even very small separations of the femoral head (<0.60mm). Debris suspended near the equator of the cup at the site of maximum fluid velocity just before the subluxation began could be transported to within 11 degrees from the cup pole. Larger head diameters resulted in increased fluid velocity at all sites around the entrance to the gap compared to smaller head sizes, with fluid velocity being greatest along the anterosuperolateral cup edge, for all head sizes. Fluid pathlines indicated that suspended debris would reach similar angular positions in the bearing space regardless of head size. Increased inset of the femoral head into the acetabular cup resulted both in higher fluid velocity and in transport of third-body debris further into the bearing space.

Crew Configuration, Ingress/Egress Procedures, and In-Flight Caregiving Capacity in a Space Ambulance Based on the Boeing X-37B

NASA Astrophysics Data System (ADS)

Halberg, Ephriam Etan

This study proposes that a Boeing X-37B space plane, its dimensions and performance characteristics estimated from publicly available documents, diagrams, and photographs, could be internally redesigned as a medical evacuation (ambulance) vehicle for the International Space Station. As of 2017, there is currently no spacecraft designed to accommodate a contingency medical evacuation wherein a crew member aboard the ISS is injured or ailing and must be returned to Earth for immediate medical attention. The X-37B is an unmanned vehicle with a history of success in both sub-orbital testing and all four of its long-duration orbital missions to date. Research conducted at UC Davis suggests that it is possible to retain the outer mold line of the X-37B while expanding the internal payload compartment to a volume sufficient for a crew of three--pilot, crew medical officer, and injured crew member--throughout ISS un-dock and atmospheric entry, descent, and landing. In addition to crew life support systems, this re-purposed X-37B, hereafter referred to as the X-37SA (Space Ambulance), includes medical equipment for stabilization of a patient in-transit. This study suggests an optimal, ergonomic crew configuration and berthing port location, procedures for microgravity ingress and 1G egress, a minimum medical equipment list and location within the crew cabin for the medical care and monitoring equipment. Conceptual crew configuration, ingress/egress procedures, and patient/equipment access are validated via physical simulation in a full-scale mockup of the proposed X-37SA crew cabin.

Transport phenomena in environmental engineering

NASA Astrophysics Data System (ADS)

Sander, Aleksandra; Kardum, Jasna Prlić; Matijašić, Gordana; Žižek, Krunoslav

2018-01-01

A term transport phenomena arises as a second paradigm at the end of 1950s with high awareness that there was a strong need to improve the scoping of chemical engineering science. At that point, engineers became highly aware that it is extremely important to take step forward from pure empirical description and the concept of unit operations only to understand the specific process using phenomenological equations that rely on three elementary physical processes: momentum, energy and mass transport. This conceptual evolution of chemical engineering was first presented with a well-known book of R. Byron Bird, Warren E. Stewart and Edwin N. Lightfoot, Transport Phenomena, published in 1960 [1]. What transport phenomena are included in environmental engineering? It is hard to divide those phenomena through different engineering disciplines. The core is the same but the focus changes. Intention of the authors here is to present the transport phenomena that are omnipresent in treatment of various process streams. The focus in this chapter is made on the transport phenomena that permanently occur in mechanical macroprocesses of sedimentation and filtration for separation in solid-liquid particulate systems and on the phenomena of the flow through a fixed and a fluidized bed of particles that are immanent in separation processes in packed columns and in environmental catalysis. The fundamental phenomena for each thermal and equilibrium separation process technology are presented as well. Understanding and mathematical description of underlying transport phenomena result in scoping the separation processes in a way that ChEs should act worldwide.

Hessdalen Light Phenomena and the Inconsistency of the "Car-Headlight" Interpretation

NASA Astrophysics Data System (ADS)

Teodorani, M.

Some gratuitous criticism attempted to attack research concerning the scientific study of anomalous light phenomena in Hessdalen, Norway, by artfully constructing a castle in the air based on the arbitrary assumption that the "EMBLA 2002" field-study was dedicated to car headlights. This paper summarizes and analyzes in a few essential details the reasons why this "criticism" hasn't any reason to be considered such, as it is only a well-constructed fake. Some epistemological aspects are treated as well.

Lattice Boltzmann modeling of transport phenomena in fuel cells and flow batteries

NASA Astrophysics Data System (ADS)

Xu, Ao; Shyy, Wei; Zhao, Tianshou

2017-06-01

Fuel cells and flow batteries are promising technologies to address climate change and air pollution problems. An understanding of the complex multiscale and multiphysics transport phenomena occurring in these electrochemical systems requires powerful numerical tools. Over the past decades, the lattice Boltzmann (LB) method has attracted broad interest in the computational fluid dynamics and the numerical heat transfer communities, primarily due to its kinetic nature making it appropriate for modeling complex multiphase transport phenomena. More importantly, the LB method fits well with parallel computing due to its locality feature, which is required for large-scale engineering applications. In this article, we review the LB method for gas-liquid two-phase flows, coupled fluid flow and mass transport in porous media, and particulate flows. Examples of applications are provided in fuel cells and flow batteries. Further developments of the LB method are also outlined.

Switching Phenomena

NASA Astrophysics Data System (ADS)

Stanley, H. E.; Buldyrev, S. V.; Franzese, G.; Havlin, S.; Mallamace, F.; Mazza, M. G.; Kumar, P.; Plerou, V.; Preis, T.; Stokely, K.; Xu, L.

One challenge of biology, medicine, and economics is that the systems treated by these serious scientific disciplines can suddenly "switch" from one behavior to another, even though they possess no perfect metronome in time. As if by magic, out of nothing but randomness one finds remarkably fine-tuned processes in time. The past century has, philosophically, been concerned with placing aside the human tendency to see the universe as a fine-tuned machine. Here we will address the challenge of uncovering how, through randomness (albeit, as we shall see, strongly correlated randomness), one can arrive at some of the many temporal patterns in physics, economics, and medicine and even begin to characterize the switching phenomena that enable a system to pass from one state to another. We discuss some applications of correlated randomness to understanding switching phenomena in various fields. Specifically, we present evidence from experiments and from computer simulations supporting the hypothesis that water's anomalies are related to a switching point (which is not unlike the "tipping point" immortalized by Malcolm Gladwell), and that the bubbles in economic phenomena that occur on all scales are not "outliers" (another Gladwell immortalization).

Toxicological Assessment of ISS Air Quality: June - September 2013 (Increment 36)

NASA Technical Reports Server (NTRS)

Meyers, Valerie

2014-01-01

Fourteen mini grab sample containers (msGSCs) were collected on ISS between June and September 2013 and were returned on 34S; however, the ATV-4 first ingress mGSC did not contain sufficient sample to report results (initial sample pressure = 1.2 psia). Of the remaining 13 mGSCs, 12 were collected as routine monthly samples in the Russian Service Module (SM), US Laboratory (Lab), and either the Japanese Pressurized Module (JPM) or the Columbus module (Col), and 1 was collected during HTV-4 first ingress. A summary of the analytical results from the 13 valid mGSCs is shown.

Free-Surface Fluid-Object Interaction for the Large-Scale Computation of Ship Hydrodynamics Phenomena

DTIC Science & Technology

2014-05-21

simulating air-water free -surface flow, fluid-object interaction (FOI), and fluid-structure interaction (FSI) phenomena for complex geometries, and...with no limitations on the motion of the free surface, and with particular emphasis on ship hydrodynamics. The following specific research objectives...were identified for this project: 1) Development of a theoretical framework for free -surface flow, FOI and FSI that is a suitable starting point

Exogenous factors contributing to column bed heterogeneity: Part 1: Consequences of 'air' injections in liquid chromatography.

PubMed

Samuelsson, Jörgen; Fornstedt, Torgny; Shalliker, Andrew

2015-08-07

It has been shown that not only the packing homogeneity, but also factors external to the column bed, such as, frits and distributors can have important effects on the column performance. This current communication is the first in a series focusing on the impact of exogenous factors on the column bed heterogeneity. This study is based on several observations by us and others that chromatographic runs often, for technical reasons, include more or less portions of air in the injections. It is therefore extremely important to find out the impact of air on the column performance, the reliability of the results derived from analyses where air was injected, and the effect on the column homogeneity. We used a photographic approach for visualising the air transport phenomena, and found that the air transport through the column is comprised of many different types of transport phenomena, such as laminal flow, viscous fingering like flows, channels and bulbs, and pulsations. More particularly, the air clouds within the column definitely interact in the adsorption, i.e. mobile phase adsorbed to the column surface is displaced. In addition, irrespective of the type of air transport phenomena, the air does not penetrate the column homogeneously. This process is strongly flow dependent. In this work we study air transport both in an analytical scale and a semi-prep column. Copyright © 2015. Published by Elsevier B.V.

Ion exchange phenomena

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

Bourg, I.C.; Sposito, G.

Ion exchange phenomena involve the population of readily exchangeable ions, the subset of adsorbed solutes that balance the intrinsic surface charge and can be readily replaced by major background electrolyte ions (Sposito, 2008). These phenomena have occupied a central place in soil chemistry research since Way (1850) first showed that potassium uptake by soils resulted in the release of an equal quantity of moles of charge of calcium and magnesium. Ion exchange phenomena are now routinely modeled in studies of soil formation (White et al., 2005), soil reclamation (Kopittke et al., 2006), soil fertilitization (Agbenin and Yakubu, 2006), colloidal dispersion/flocculationmore » (Charlet and Tournassat, 2005), the mechanics of argillaceous media (Gajo and Loret, 2007), aquitard pore water chemistry (Tournassat et al., 2008), and groundwater (Timms and Hendry, 2007; McNab et al., 2009) and contaminant hydrology (Chatterjee et al., 2008; van Oploo et al., 2008; Serrano et al., 2009).« less

Teaching optical phenomena with Tracker

NASA Astrophysics Data System (ADS)

Rodrigues, M.; Simeão Carvalho, P.

2014-11-01

Since the invention and dissemination of domestic laser pointers, observing optical phenomena is a relatively easy task. Any student can buy a laser and experience at home, in a qualitative way, the reflection, refraction and even diffraction phenomena of light. However, quantitative experiments need instruments of high precision that have a relatively complex setup. Fortunately, nowadays it is possible to analyse optical phenomena in a simple and quantitative way using the freeware video analysis software ‘Tracker’. In this paper, we show the advantages of video-based experimental activities for teaching concepts in optics. We intend to show: (a) how easy the study of such phenomena can be, even at home, because only simple materials are needed, and Tracker provides the necessary measuring instruments; and (b) how we can use Tracker to improve students’ understanding of some optical concepts. We give examples using video modelling to study the laws of reflection, Snell’s laws, focal distances in lenses and mirrors, and diffraction phenomena, which we hope will motivate teachers to implement it in their own classes and schools.

Different states of the transient luminous phenomena in Hessdalen valley, Norway.

NASA Astrophysics Data System (ADS)

Hauge, B. G.; Montebugnoli, S.

2012-04-01

The transient luminous phenomena's in Hessdalen valley has at least been observed for 200 years, since 1811, when the priest Jacob T. Krogh did the first written documentation. The valley is located in the middle of Norway, isolated and with sub arctic climate. The former mining district has no more than 140 inhabitants, and the deep mines are closed and filled with water. The valley has been under scientific surveillance since 1998 when the first automated and remote controlled observatory was put into action. Today a Norwegian, Italian and French collaboration runs 3 different research stations inside the valley. Each year a scientific field campaign establishes 4 temporary bases in the mountains, and up to 100 students and researchers man these bases for up to 14 days in september when the moon is down. The Hessdalen phenomena is not easy to detect, and approximately only 20 observations is done each year. The work done the last 14 years suggests that the phenomenon has different states, at least 6 detected so far. The states are so different that to se a coupling between them is difficult. New work done into dusty plasma physics suggest that the different phenomena's may be of the same origin, since the ionized grains of dusty plasma can change states from weakly coupled (gaseous) to crystalline, altering shape/formation and leading to different phenomena. Optical spectrometry from 2007 suggested that the luminous phenomena consisted of burning air and dust from the valley. Work done by G.S Paiva and C.A Taft suggests that radon decay from closed mines may be the mechanism that ionizes dust and triggers this phenomena. The 6 different main states of the Hessdalen phenomena, Doublet, Fireball, Plasma ray, Dust cloud, Flash and Invisible state is described and discussed. Investigation of the atmosphere inside the Hessdalen valley with low frequency directional RADAR, reveals large areas of ionized matter, giving a reflecting area big enough to saturate the input

Aura phenomena during syncope.

PubMed

Benke, T; Hochleitner, M; Bauer, G

1997-01-01

We studied the frequency and clinical characteristics of aura phenomena in 60 patients with cardiac and 40 subjects with vasovagal syncopes. The majority (93%) of all syncope patients recalled having experienced an aura. Aura phenomena were similar in both groups and were mostly compound auras comprising epigastric, vertiginous, visual, or somatosensory experiences, but were more detailed in the noncardiac group. The localizing significance of auras preceding a syncope was generally poor. Although hard to distinguish from epileptic auras from their structure and shape, syncope-related auras lacked symptoms that are commonly reported after epileptic seizures such as tastes, smells, déjà vu phenomena, scenic visual perceptions, and speech impairments. A detailed anamnestic exploration of auras seems worthwhile in unexplained disorders of consciousness.

The simulation of air recirculation and fire/explosion phenomena within a semiconductor factory.

PubMed

I, Yet-Pole; Chiu, Yi-Long; Wu, Shi-Jen

2009-04-30

The semiconductor industry is the collection of capital-intensive firms that employ a variety of hazardous chemicals and engage in the design and fabrication of semiconductor devices. Owing to its processing characteristics, the fully confined structure of the fabrication area (fab) and the vertical airflow ventilation design restrict the applications of traditional consequence analysis techniques that are commonly used in other industries. The adverse situation also limits the advancement of a fire/explosion prevention design for the industry. In this research, a realistic model of a semiconductor factory with a fab, sub-fabrication area, supply air plenum, and return air plenum structures was constructed and the computational fluid dynamics algorithm was employed to simulate the possible fire/explosion range and its severity. The semiconductor factory has fan module units with high efficiency particulate air filters that can keep the airflow uniform within the cleanroom. This condition was modeled by 25 fans, three layers of porous ceiling, and one layer of porous floor. The obtained results predicted very well the real airflow pattern in the semiconductor factory. Different released gases, leak locations, and leak rates were applied to investigate their influence on the hazard range and severity. Common mitigation measures such as a water spray system and a pressure relief panel were also provided to study their potential effectiveness to relieve thermal radiation and overpressure hazards within a fab. The semiconductor industry can use this simulation procedure as a reference on how to implement a consequence analysis for a flammable gas release accident within an air recirculation cleanroom.

Autonomous urban reconnaissance ingress system (AURIS): providing a tactically relevant autonomous door-opening kit for unmanned ground vehicles

NASA Astrophysics Data System (ADS)

Shane, David J.; Rufo, Michael A.; Berkemeier, Matthew D.; Alberts, Joel A.

2012-06-01

The Autonomous Urban Reconnaissance Ingress System (AURIS™) addresses a significant limitation of current military and first responder robotics technology: the inability of reconnaissance robots to open doors. Leveraging user testing as a baseline, the program has derived specifications necessary for military personnel to open doors with fielded UGVs (Unmanned Ground Vehicles), and evaluates the technology's impact on operational mission areas: duration, timing, and user patience in developing a tactically relevant, safe, and effective system. Funding is provided through the US ARMY Tank Automotive Research, Development and Engineering Center (TARDEC) and the project represents a leap forward in perception, autonomy, robotic implements, and coordinated payload operation in UGVs. This paper describes high level details of specification generation, status of the last phase of development, an advanced view of the system autonomy capability, and a short look ahead towards the ongoing work on this compelling and important technology.

An analysis of short haul air passenger demand, volume 2

NASA Technical Reports Server (NTRS)

Blumer, T. P.; Swan, W. M.

1978-01-01

Several demand models for short haul air travel are proposed and calibrated on pooled data. The models are designed to predict demand and analyze some of the motivating phenomena behind demand generation. In particular, an attempt is made to include the effects of competing modes and of alternate destinations. The results support three conclusions: (1) the auto mode is the air mode's major competitor; (2) trip time is an overriding factor in intermodal competition, with air fare at its present level appearing unimportant to the typical short haul air traveler; and (3) distance appears to underly several demand generating phenomena, and therefore, must be considered very carefully to any intercity demand model. It may be the cause of the wide range of fare elasticities reported by researchers over the past 15 years. A behavioral demand model is proposed and calibrated. It combines the travel generating effects of income and population, the effects of modal split, the sensitivity of travel to price and time, and the effect of alternative destinations satisfying the trip purpose.

Hydrochemical analysis to evaluate the seawater ingress in a small coral island of India.

PubMed

Banerjee, Pallavi; Singh, V S; Singh, Ajay; Prasad, R K; Rangarajan, R

2012-06-01

The sustainable development of the limited groundwater resources in the tropical island requires a thorough understanding of detail hydrogeological regime including the hydrochemical behavior of groundwater. Detail analysis of chemical data of groundwater helps in assessing the different groundwater zone affected by formation as well as sea water. Groundwater and saline water interaction is better understood using groundwater major ion chemistry over an island aquifer. Multivariate methods to analyze the geochemical data are used to understand geochemical evolution of groundwater. The methods are successfully used to group the data to evaluate influence of various environs in the study area. Various classification methods such as piper, correlation method, and salinity hazard measurements are also employed to critical study of geochemical characteristics of groundwater to identify vulnerable parts of the aquifer. These approaches have been used to successfully evaluate the aquifer zones of a tiny island off the west coast of India. The most part of island is found to be safe for drinking, however some parts of island are identified that are affected by sea water ingress and dissolution of formation minerals. The analysis has successfully leaded to identification of that part of aquifer on the island which needs immediate attention for restoration and avoids further deterioration.

Crystallization phenomena in slags

NASA Astrophysics Data System (ADS)

Orrling, Carl Folke

2000-09-01

The crystallization of the mold slag affects both the heat transfer and the lubrication between the mold and the strand in continuous casting of steel. In order for mold slag design to become an engineering science rather than an empirical exercise, a fundamental understanding of the melting and solidification behavior of a slag must be developed. Thus it is necessary to be able to quantify the phenomena that occur under the thermal conditions that are found in the mold of a continuous caster. The double hot thermocouple technique (DHTT) and the Confocal Laser Scanning Microscope used in this study are two novel techniques for investigating melting and solidification phenomena of transparent slags. Results from these techniques are useful in defining the phenomena that occur when the slag film infiltrates between the mold and the shell of the casting. TTT diagrams were obtained for various slags and indicated that the onset of crystallization is a function of cooling rate and slag chemistry. Crystal morphology was found to be dependent upon the experimental temperature and four different morphologies were classified based upon the degree of melt undercooling. Continuous cooling experiments were carried out to develop CCT diagrams and it was found that the amount and appearance of the crystalline fraction greatly depends on the cooling conditions. The DHTT can also be used to mimic the cooling profile encountered by the slag in the mold of a continuous caster. In this differential cooling mode (DCT), it was found that the details of the cooling rate determine the actual response of the slag to a thermal gradient and small changes can lead to significantly different results. Crystal growth rates were measured and found to be in the range between 0.11 mum/s to 11.73 mum/s depending on temperature and slag chemistry. Alumina particles were found to be effective innoculants in oxide melts reducing the incubation time for the onset of crystallization and also extending

Dynamic of Air Invasion in an Immersed Granular Layer

NASA Astrophysics Data System (ADS)

Varas, G.; Ramos, G.; Géminard, J. C.; Vidal, V.

2014-12-01

Displacement processes (typically, grains displaced by a fluid) are the driving mechanism which control the dynamics of many geological processes (e.g. oil extraction, air sparging, piercement structures). They also play an important role in a wide range of industrial applications, from ground water hydrology and soil mechanics to agricultural engineering. The interaction between one or more moving fluids (e.g. rising gas immersed in a granular medium) and grains control the dynamics of these phenomena. Due to their economic and ecological importance, it is essential to understand the variety and potentiality of these phenomena. When an ascending air passes trough an immersed granular bed its fluidized producing the grains to start to move. When this process is repeated, its created a fluidized zone that evolves over time. Here, we investigate the morphology and dynamics of the region invaded by air as a function of a dimensionless parameter χ which accounts for the relative effects of the gravity and the capillarity. We propose new experimental observations on the air invasion regimes and on the morphology of the fluidized zone, in particular its growth dynamics.

A Study of Aircraft Fire Hazards Related to Natural Electrical Phenomena

NASA Technical Reports Server (NTRS)

Kester, Frank L.; Gerstein, Melvin; Plumer, J. A.

1960-01-01

The problems of natural electrical phenomena as a fire hazard to aircraft are evaluated. Assessment of the hazard is made over the range of low level electrical discharges, such as static sparks, to high level discharges, such as lightning strikes to aircraft. In addition, some fundamental work is presented on the problem of flame propagation in aircraft fuel vent systems. This study consists of a laboratory investigation in five parts: (1) a study of the ignition energies and flame propagation rates of kerosene-air and JP-6-air foams, (2) a study of the rate of flame propagation of n-heptane, n-octane, n-nonane, and n-decane in aircraft vent ducts, (3) a study of the damage to aluminum, titanium, and stainless steel aircraft skin materials by lightning strikes, (4) a study of fuel ignition by lightning strikes to aircraft skins, and (5) a study of lightning induced flame propagation in an aircraft vent system.

Dependence of charge transfer phenomena during solid-air two-phase flow on particle disperser

NASA Astrophysics Data System (ADS)

Tanoue, Ken-ichiro; Suedomi, Yuuki; Honda, Hirotaka; Furutani, Satoshi; Nishimura, Tatsuo; Masuda, Hiroaki

2012-12-01

An experimental investigation of the tribo-electrification of particles has been conducted during solid-air two-phase turbulent flow. The current induced in a metal plate by the impact of polymethylmethacrylate (PMMA) particles in a high-speed air flow was measured for two different plate materials. The results indicated that the contact potential difference between the particles and a stainless steel plate was positive, while for a nickel plate it was negative. These results agreed with theoretical contact charge transfer even if not only the particle size but also the kind of metal plate was changed. The specific charge of the PMMA particles during solid-air two-phase flow using an ejector, a stainless steel branch pipe, and a stainless steel straight pipe was measured using a Faraday cage. Although the charge was negative in the ejector, the particles had a positive specific charge at the outlet of the branch pipe, and this positive charge increased in the straight pipe. The charge decay along the flow direction could be reproduced by the charging and relaxation theory. However, the proportional coefficients in the theory changed with the particle size and air velocity. Therefore, an unexpected charge transfer occurred between the ejector and the branch pipe, which could not be explained solely by the contact potential difference. In the ejector, an electrical current in air might have been produced by self-discharge of particles with excess charge between the nickel diffuser in the ejector and the stainless steel nozzle or the stainless steel pipe due to a reversal in the contact potential difference between the PMMA and the stainless steel. The sign of the current depended on the particle size, possibly because the position where the particles impacted depended on their size. When dual coaxial glass pipes were used as a particle disperser, the specific charge of the PMMA particles became more positive along the particle flow direction due to the contact

Continuum-based DFN-consistent simulations of oxygen ingress in fractured crystalline rocks

NASA Astrophysics Data System (ADS)

Trinchero, P.; Puigdomenech, I.; Molinero, J.; Ebrahimi, H.; Gylling, B.; Svensson, U.; Bosbach, D.; Deissmann, G.

2016-12-01

The potential transient infiltration of oxygenated glacial meltwater into initially anoxic and reducing fractured crystalline rocks during glaciation events is an issue of concern for some of the prospected deep geological repositories for spent nuclear fuel. Here, this problem is assessed using reactive transport calculations. First, a novel parameterisation procedure is presented, where flow, transport and geochemical parameters (i.e. hydraulic conductivity, effective/kinetic porosity, and mineral specific surface and abundance) are defined on a finite volume numerical grid based on the (spatially varying) properties of an underlying Discrete Fracture Network (DFN). Second, using this approach, a realistic reactive transport model of Forsmark, i.e. the selected site for the proposed Swedish spent nuclear fuel repository, is implemented. The model consists of more than 70 million geochemical transport degrees of freedom and simulates the ingress of oxygen-rich water from the recharge area of the domain and its depletion due to reactions with the Fe(II) mineral chlorite. Third, the calculations are solved in the supercomputer JUQUEEN of the Jülich Supercomputing Centre. The results of the simulations show that oxygen infiltrates relatively quickly along fractures and deformation zones until a steady state profile is reached, where geochemical reactions counterbalance advective transport processes. Interestingly, most of the iron-bearing minerals are consumed in the highly conductive zones, where larger mineral surfaces are available for reactions. An analysis based on mineral mass balance shows that the considered rock medium has enough capacity to buffer oxygen infiltration for a long period of time (i.e. some thousand years).

Investigation of the quality of stored red blood cells after simulated air drop in the maritime environment.

PubMed

Meli, Athinoula; Hancock, Vicky; Doughty, Heidi; Smedley, Steve; Cardigan, Rebecca; Wiltshire, Michael

2018-02-01

Maritime medical capability may be compromised by blood resupply. Air-dropped red blood cells (RBCs) is a possible mitigation factor. This study set out to evaluate RBC storage variables after a simulated parachute air drop into the sea, as limited data exist. The air load construction for the air drop of blood was subject to static drop assessment to simulate a worst-case parachute drop scenario. One control and two test Golden Hour shipping containers were each packaged with 10 RBC units. The control box was not dropped; Test Boxes 1 and 2 were further reinforced with waterproof boxes and underwent a simulated air drop on Day 7 or Day 8 postdonation, respectively. One day after the drop and once a week thereafter until Day 43 of storage, RBCs from each box were sampled and tested for full blood counts, hemolysis, adenosine triphosphate, 2,3-diphosphoglycerate, pH, extracellular potassium, glucose, lactate, deformability, and RBC microvesicles. The packaging configuration completed the air drop with no water ingress or physical damage. All units met UK specifications for volume, hemoglobin, and hemolysis. There were no significant differences for any of the variables studied between RBCs in the control box compared to RBCs in Test Boxes 1 and 2 combined over storage. The test proved that the packaging solution and the impact of a maritime air drop as performed in this study, on Day 7 or Day 8 postdonation, did not affect the in vitro quality of RBCs in SAGM over storage for 35 days. © 2017 AABB.

Teaching Optical Phenomena with Tracker

ERIC Educational Resources Information Center

Rodrigues, M.; Carvalho, P. Simeão

2014-01-01

Since the invention and dissemination of domestic laser pointers, observing optical phenomena is a relatively easy task. Any student can buy a laser and experience at home, in a qualitative way, the reflection, refraction and even diffraction phenomena of light. However, quantitative experiments need instruments of high precision that have a…

Optical Air Flow Measurements for Flight Tests and Flight Testing Optical Air Flow Meters

NASA Technical Reports Server (NTRS)

Jentink, Henk W.; Bogue, Rodney K.

2005-01-01

Optical air flow measurements can support the testing of aircraft and can be instrumental to in-flight investigations of the atmosphere or atmospheric phenomena. Furthermore, optical air flow meters potentially contribute as avionics systems to flight safety and as air data systems. The qualification of these instruments for the flight environment is where we encounter the systems in flight testing. An overview is presented of different optical air flow measurement techniques applied in flight and what can be achieved with the techniques for flight test purposes is reviewed. All in-flight optical airflow velocity measurements use light scattering. Light is scattered on both air molecules and aerosols entrained in the air. Basic principles of making optical measurements in flight, some basic optical concepts, electronic concepts, optoelectronic interfaces, and some atmospheric processes associated with natural aerosols are reviewed. Safety aspects in applying the technique are shortly addressed. The different applications of the technique are listed and some typical examples are presented. Recently NASA acquired new data on mountain rotors, mountain induced turbulence, with the ACLAIM system. Rotor position was identified using the lidar system and the potentially hazardous air flow profile was monitored by the ACLAIM system.

Transport Phenomena.

ERIC Educational Resources Information Center

McCready, Mark J.; Leighton, David T.

1987-01-01

Discusses the problems created in graduate chemical engineering programs when students enter with a wide diversity of understandings of transport phenomena. Describes a two-semester graduate transport course sequence at the University of Notre Dame which focuses on fluid mechanics and heat and mass transfer. (TW)

Observation of Celestial Phenomena in Ancient China

NASA Astrophysics Data System (ADS)

Sun, Xiaochun

Because of the need for calendar-making and portent astrology, the Chinese were diligent and meticulous observers of celestial phenomena. China has maintained the longest continuous historical records of celestial phenomena in the world. Extraordinary or abnormal celestial events were particularly noted because of their astrological significance. The historical records cover various types of celestial phenomena, which include solar and lunar eclipses, sunspots, "guest stars" (novae or supernovae as we understand today), comets and meteors, and all kinds of planetary phenomena. These records provide valuable historical data for astronomical studies today.

The NASA Air Traffic Management Ontology: Technical Documentation

NASA Technical Reports Server (NTRS)

Keller, Richard M.

2017-01-01

This document is intended to serve as comprehensive documentation for the NASA Air Traffic Management (ATM) Ontology. The ATM Ontology is a conceptual model that defines key classes of entities and relationships pertaining to the US National Airspace System (NAS) and the management of air traffic through that system. A wide variety of classes are represented in the ATM Ontology, including classes corresponding to flights, aircraft, manufacturers, airports, airlines, air routes, NAS facilities, air traffic control advisories, weather phenomena, and many others. The Ontology can be useful in the context of a variety of information management tasks relevant to NAS, including information exchange, data query and search, information organization, information integration, and terminology standardization.

Discharge in Long Air Gaps; Modelling and applications

NASA Astrophysics Data System (ADS)

Beroual, A.; Fofana, I.

2016-06-01

Discharge in Long Air Gaps: Modelling and applications presents self-consistent predictive dynamic models of positive and negative discharges in long air gaps. Equivalent models are also derived to predict lightning parameters based on the similarities between long air gap discharges and lightning flashes. Macroscopic air gap discharge parameters are calculated to solve electrical, empirical and physical equations, and comparisons between computed and experimental results for various test configurations are presented and discussed. This book is intended to provide a fresh perspective by contributing an innovative approach to this research domain, and universities with programs in high-voltage engineering will find this volume to be a working example of how to introduce the basics of electric discharge phenomena.

Advanced modelling of the transport phenomena across horizontal clothing microclimates with natural convection.

PubMed

Mayor, T S; Couto, S; Psikuta, A; Rossi, R M

2015-12-01

The ability of clothing to provide protection against external environments is critical for wearer's safety and thermal comfort. It is a function of several factors, such as external environmental conditions, clothing properties and activity level. These factors determine the characteristics of the different microclimates existing inside the clothing which, ultimately, have a key role in the transport processes occurring across clothing. As an effort to understand the effect of transport phenomena in clothing microclimates on the overall heat transport across clothing structures, a numerical approach was used to study the buoyancy-driven heat transfer across horizontal air layers trapped inside air impermeable clothing. The study included both the internal flow occurring inside the microclimate and the external flow occurring outside the clothing layer, in order to analyze the interdependency of these flows in the way heat is transported to/from the body. Two-dimensional simulations were conducted considering different values of microclimate thickness (8, 25 and 52 mm), external air temperature (10, 20 and 30 °C), external air velocity (0.5, 1 and 3 m s(-1)) and emissivity of the clothing inner surface (0.05 and 0.95), which implied Rayleigh numbers in the microclimate spanning 4 orders of magnitude (9 × 10(2)-3 × 10(5)). The convective heat transfer coefficients obtained along the clothing were found to strongly depend on the transport phenomena in the microclimate, in particular when natural convection is the most important transport mechanism. In such scenario, convective coefficients were found to vary in wavy-like manner, depending on the position of the flow vortices in the microclimate. These observations clearly differ from data in the literature for the case of air flow over flat-heated surfaces with constant temperature (which shows monotonic variations of the convective heat transfer coefficients, along the length of the surface). The flow

Classifying prion and prion-like phenomena.

PubMed

Harbi, Djamel; Harrison, Paul M

2014-01-01

The universe of prion and prion-like phenomena has expanded significantly in the past several years. Here, we overview the challenges in classifying this data informatically, given that terms such as "prion-like", "prion-related" or "prion-forming" do not have a stable meaning in the scientific literature. We examine the spectrum of proteins that have been described in the literature as forming prions, and discuss how "prion" can have a range of meaning, with a strict definition being for demonstration of infection with in vitro-derived recombinant prions. We suggest that although prion/prion-like phenomena can largely be apportioned into a small number of broad groups dependent on the type of transmissibility evidence for them, as new phenomena are discovered in the coming years, a detailed ontological approach might be necessary that allows for subtle definition of different "flavors" of prion / prion-like phenomena.

Three cell recognition changes accompany the ingression of sea urchin primary mesenchyme cells.

PubMed

Fink, R D; McClay, D R

1985-01-01

At gastrulation the primary mesenchyme cells of sea urchin embryos lose contact with the extracellular hyaline layer and with neighboring blastomeres as they pass through the basal lamina and enter the blastocoel. This delamination process was examined using a cell-binding assay to follow changes in affinities between mesenchyme cells and their three substrates: hyalin, early gastrula cells, and basal lamina. Sixteen-cell-stage micromeres (the precursors of primary mesenchyme cells), and mesenchyme cells obtained from mesenchyme-blastula-stage embryos were used in conjunction with micromeres raised in culture to intermediate ages. The micromeres exhibited an affinity for hyalin, but the affinity was lost at the time of mesenchyme ingression in vivo. Similarly, micromeres had an affinity for monolayers of gastrula cells but the older mesenchyme cells lost much of their cell-to-cell affinity. Presumptive ectoderm and endoderm cells tested against the gastrula monolayers showed no decrease in binding over the same time interval. When micromeres and primary mesenchyme cells were tested against basal lamina preparations, there was an increase in affinity that was associated with developmental time. Presumptive ectoderm and endoderm cells showed no change in affinity over the same interval. Binding measurements using isolated basal laminar components identified fibronectin as one molecule for which the wandering primary mesenchyme cells acquired a specific affinity. The data indicate that as the presumptive mesenchyme cells leave the vegetal plate of the embryo they lose affinities for hyalin and for neighboring cells, and gain an affinity for fibronectin associated with the basal lamina and extracellular matrix that lines the blastocoel.

Subway platform air quality: Assessing the influences of tunnel ventilation, train piston effect and station design

NASA Astrophysics Data System (ADS)

Moreno, T.; Pérez, N.; Reche, C.; Martins, V.; de Miguel, E.; Capdevila, M.; Centelles, S.; Minguillón, M. C.; Amato, F.; Alastuey, A.; Querol, X.; Gibbons, W.

2014-08-01

A high resolution air quality monitoring campaign (PM, CO2 and CO) was conducted on differently designed station platforms in the Barcelona subway system under: (a) normal forced tunnel ventilation, and (b) with daytime tunnel ventilation systems shut down. PM concentrations are highly variable (6-128 μgPM1 m-3, 16-314 μgPM3 m-3, and 33-332 μgPM10 m-3, 15-min averages) depending on ventilation conditions and station design. Narrow platforms served by single-track tunnels are heavily dependent on forced tunnel ventilation and cannot rely on the train piston effect alone to reduce platform PM concentrations. In contrast PM levels in stations with spacious double-track tunnels are not greatly affected when tunnel ventilation is switched off, offering the possibility of significant energy savings without damaging air quality. Sampling at different positions along the platform reveals considerable lateral variation, with the greatest accumulation of particulates occurring at one end of the platform. Passenger accesses can dilute PM concentrations by introducing cleaner outside air, although lateral down-platform accesses are less effective than those positioned at the train entry point. CO concentrations on the platform are very low (≤1 ppm) and probably controlled by ingress of traffic-contaminated street-level air. CO2 averages range from 371 to 569 ppm, changing during the build-up and exchange of passengers with each passing train.

Measuring Air Density in the Introductory Lab

ERIC Educational Resources Information Center

Calza, G.; Gratton, L. M.; Lopez-Arias, T.; Oss, S.

2010-01-01

The measurement of the mass, or the density, of air can easily be done with very simple materials and offers many interesting phenomena for discussion--buoyancy and its effects being the most obvious but not the only one. Many interesting considerations can be done regarding the behavior of gases, the effect of the external conditions in the…

The nature of the air-cleaved mica surface

NASA Astrophysics Data System (ADS)

Christenson, Hugo K.; Thomson, Neil H.

2016-06-01

The accepted image of muscovite mica is that of an inert and atomically smooth surface, easily prepared by cleavage in an ambient atmosphere. Consequently, mica is extensively used a model substrate in many fundamental studies of surface phenomena and as a substrate for AFM imaging of biomolecules. In this review we present evidence from the literature that the above picture is not quite correct. The mica used in experimental work is almost invariably cleaved in laboratory air, where a reaction between the mica surface, atmospheric CO2 and water occurs immediately after cleavage. The evidence suggests very strongly that as a result the mica surface becomes covered by up to one formula unit of K2CO3 per nm2, which is mobile under humid conditions, and crystallises under drier conditions. The properties of mica in air or water vapour cannot be fully understood without reference to the surface K2CO3, and many studies of the structure of adsorbed water on mica surfaces may need to be revisited. With this new insight, however, the air-cleaved mica should provide exciting opportunities to study phenomena such as two-dimensional ion diffusion, electrolyte effects on surface conductivity, and two-dimensional crystal nucleation.

Self field electromagnetism and quantum phenomena

NASA Astrophysics Data System (ADS)

Schatten, Kenneth H.

1994-07-01

Quantum Electrodynamics (QED) has been extremely successful inits predictive capability for atomic phenomena. Thus the greatest hope for any alternative view is solely to mimic the predictive capability of quantum mechanics (QM), and perhaps its usefulness will lie in gaining a better understanding of microscopic phenomena. Many ?paradoxes? and problematic situations emerge in QED. To combat the QED problems, the field of Stochastics Electrodynamics (SE) emerged, wherein a random ?zero point radiation? is assumed to fill all of space in an attmept to explain quantum phenomena, without some of the paradoxical concerns. SE, however, has greater failings. One is that the electromagnetic field energy must be infinit eto work. We have examined a deterministic side branch of SE, ?self field? electrodynamics, which may overcome the probelms of SE. Self field electrodynamics (SFE) utilizes the chaotic nature of electromagnetic emissions, as charges lose energy near atomic dimensions, to try to understand and mimic quantum phenomena. These fields and charges can ?interact with themselves? in a non-linear fashion, and may thereby explain many quantum phenomena from a semi-classical viewpoint. Referred to as self fields, they have gone by other names in the literature: ?evanesccent radiation?, ?virtual photons?, and ?vacuum fluctuations?. Using self fields, we discuss the uncertainty principles, the Casimir effects, and the black-body radiation spectrum, diffraction and interference effects, Schrodinger's equation, Planck's constant, and the nature of the electron and how they might be understood in the present framework. No new theory could ever replace QED. The self field view (if correct) would, at best, only serve to provide some understanding of the processes by which strange quantum phenomena occur at the atomic level. We discuss possible areas where experiments might be employed to test SFE, and areas where future work may lie.

Light flash phenomena induced by HzE particles

NASA Technical Reports Server (NTRS)

Mcnulty, P. J.; Pease, V. P.

1980-01-01

Astronauts and Apollo and Skylab missions have reported observing a variety of visual phenomena when their eyes are closed and adapted to darkness. These phenomena have been collectively labelled as light flashes. Visual phenomena which are similar in appearance to those observed in space have been demonstrated at the number of accelerator facilities by expressing the eyes of human subjects to beams of various types of radiation. In some laboratory experiments Cerenkov radiation was found to be the basis for the flashes observed while in other experiments Cerenkov radiation could apparently be ruled out. Experiments that differentiate between Cerenkov radiation and other possible mechanisms for inducing visual phenomena was then compared. The phenomena obtained in the presence and absence of Cerenkov radiation were designed and conducted. A new mechanism proposed to explain the visual phenomena observed by Skylab astronauts as they passed through the South Atlantic Anomaly, namely nuclear interactions in and near the sensitive layer of the retina, is covered. Also some studies to search for similar transient effects of space radiation on sensors and microcomputer memories are described.

Hydrocode simulations of air and water shocks for facility vulnerability assessments.

PubMed

Clutter, J Keith; Stahl, Michael

2004-01-02

Hydrocodes are widely used in the study of explosive systems but their use in routine facility vulnerability assessments has been limited due to the computational resources typically required. These requirements are due to the fact that the majority of hydrocodes have been developed primarily for the simulation of weapon-scale phenomena. It is not practical to use these same numerical frameworks on the large domains found in facility vulnerability studies. Here, a hydrocode formulated specifically for facility vulnerability assessments is reviewed. Techniques used to accurately represent the explosive source while maintaining computational efficiency are described. Submodels for addressing other issues found in typical terrorist attack scenarios are presented. In terrorist attack scenarios, loads produced by shocks play an important role in vulnerability. Due to the difference in the material properties of water and air and interface phenomena, there exists significant contrast in wave propagation phenomena in these two medium. These physical variations also require special attention be paid to the mathematical and numerical models used in the hydrocodes. Simulations for a variety of air and water shock scenarios are presented to validate the computational models used in the hydrocode and highlight the phenomenological issues.

Drop impact on a solid surface at reduced air pressure

NASA Astrophysics Data System (ADS)

Langley, Kenneth; Li, E. Q.; Tian, Y. S.; Hicks, P. D.; Thoroddsen, S. T.

2017-11-01

When a drop approaches a solid surface at atmospheric pressure, the lubrication pressure within the air forms a dimple in the bottom of the drop resulting in the entrainment of an air disc upon impact. Reducing the ambient air pressure below atmospheric has been shown to suppress splashing and the compression of the intervening air could be significant on the air disc formation; however, to date there have been no experimental studies showing how the entrainment of the air disc is affected by reducing the ambient pressure. Using ultra-high-speed interferometry, at up to 5 Mfps, we investigate droplet impacts onto dry solid surfaces in reduced ambient air pressures with particular interest in what happens as rarified gas effects become important, i.e. when the thickness of the air layer is of the same magnitude as the mean free path of the air molecules. Experimental data will be presented showing novel phenomena and comparisons will be drawn with theoretical models from the literature.

Luminous Phenomena - A Scientific Investigation of Anomalous Luminous Atmospheric Phenomena

NASA Astrophysics Data System (ADS)

Teodorani, M.

2003-12-01

Anomalous atmospheric luminous phenomena reoccur in several locations of Earth, in the form of multi-color light balls characterized by large dimensions, erratic motion, long duration and a correlated electromagnetic field. The author (an astrophysicist) of this book, which is organized as a selection of some of his technical and popularizing papers and seminars, describes and discusses all the efforts that have been done in 10 years, through several missions and a massive data analysis, in order to obtain some scientific explanation of this kind of anomalies, in particular the Hessdalen anomaly in Norway. The following topics are treated in the book: a) geographic archive of the areas of Earth where such phenomena are known to reoccur most often; b) observational techniques of astrophysical kind that have been used to acquire the data; c) main scientific results obtained so far; d) physical interpretation and natural hypothesis vs. ETV hypothesis; e) historical and chronological issues; f) the importance to brindle new energy sources; g) the importance to keep distance from any kind of "ufology". An unpublished chapter is entirely devoted to a detailed scientific investigation project of light phenomena reoccurring on the Ontario lake; the chosen new-generation multi-wavelength sensing instrumentation that is planned to be used in future missions in that specific area, is described together with scientific rationale and planned procedures. The main results, which were obtained in other areas of the world, such as the Arizona desert, USA and the Sibillini Mountains, Italy, are also briefly mentioned. One chapter is entirely dedicated to the presentation of extensive abstracts of technical papers by the author concerning this specific subject. The book is accompanied with a rich source of bibliographic references.

Air entrapment under an impacting drop

NASA Astrophysics Data System (ADS)

Thoroddsen, S. T.; Etoh, T. G.; Takehara, K.

2003-03-01

When a drop impacts on a liquid surface it entraps a small amount of air under its centre as the two liquid surfaces meet. The contact occurs along a ring enclosing a thin disk of air. We use the next-generation ultra-high-speed video camera, capable of 1 million f.p.s. (Etoh et al. 2002), to study the dynamics of this air sheet as it contracts due to surface tension, to form a bubble or, more frequently, splits into two bubbles. During the contraction of the air disk an azimuthal undulation, resembling a pearl necklace, develops along its edge. The contraction speed of the sheet is accurately described by a balance between inertia and surface tension. The average initial thickness of the air sheet decreases with higher impact Reynolds numbers, becoming less than one micron. The total volume of air entrapped depends strongly on the bottom curvature of the drop at impact. A sheet of micro-bubbles is often observed along the original interface. Oguz Prosperetti bubble rings are also observed. For low Weber numbers (We<20) a variety of other entrapment phenomena appear.

Theories of dynamical phenomena in sunspots

NASA Technical Reports Server (NTRS)

Thomas, J. H.

1981-01-01

Attempts that have been made to understand and explain observed dynamical phenomena in sunspots within the framework of magnetohydrodynamic theory are surveyed. The qualitative aspects of the theory and physical arguments are emphasized, with mathematical details generally avoided. The dynamical phenomena in sunspots are divided into two categories: aperiodic (quasi-steady) and oscillatory. For each phenomenon discussed, the salient observational features that any theory should explain are summarized. The two contending theoretical models that can account for the fine structure of the Evershed motion, namely the convective roll model and the siphon flow model, are described. With regard to oscillatory phenomena, attention is given to overstability and oscillatory convection, umbral oscillations and flashes. penumbral waves, five-minute oscillations in sunspots, and the wave cooling of sunspots.

ARE CARS OR TREES MORE IMPORTANT TO PARTICULATE MATTER AIR POLUTION? WHAT RADIOCARBON MEASUREMENTS HAVE TO SAY

EPA Science Inventory

Air pollution in the form of particulate matter (PM) originates from both human activities and "natural" phenomena. Setting and achieving National Ambient Air Quality Standards (NAAQS) for PM has to take into account the latter since they are in general less controllable than th...

Time-Variable Phenomena in the Jovian System

NASA Technical Reports Server (NTRS)

Belton, Michael J. S. (Editor); West, Robert A. (Editor); Rahe, Jurgen (Editor); Pereyda, Margarita

1989-01-01

The current state of knowledge of dynamic processes in the Jovian system is assessed and summaries are provided of both theoretical and observational foundations upon which future research might be based. There are three sections: satellite phenomena and rings; magnetospheric phenomena, Io's torus, and aurorae; and atmospheric phenomena. Each chapter discusses time dependent theoretical framework for understanding and interpreting what is observed; others describe the evidence and nature of observed changes or their absence. A few chapters provide historical perspective and attempt to present a comprehensive synthesis of the current state of knowledge.

Reproducibility in Psychological Science: When Do Psychological Phenomena Exist?

PubMed Central

Iso-Ahola, Seppo E.

2017-01-01

Scientific evidence has recently been used to assert that certain psychological phenomena do not exist. Such claims, however, cannot be made because (1) scientific method itself is seriously limited (i.e., it can never prove a negative); (2) non-existence of phenomena would require a complete absence of both logical (theoretical) and empirical support; even if empirical support is weak, logical and theoretical support can be strong; (3) statistical data are only one piece of evidence and cannot be used to reduce psychological phenomena to statistical phenomena; and (4) psychological phenomena vary across time, situations and persons. The human mind is unreproducible from one situation to another. Psychological phenomena are not particles that can decisively be tested and discovered. Therefore, a declaration that a phenomenon is not real is not only theoretically and empirically unjustified but runs counter to the propositional and provisional nature of scientific knowledge. There are only “temporary winners” and no “final truths” in scientific knowledge. Psychology is a science of subtleties in human affect, cognition and behavior. Its phenomena fluctuate with conditions and may sometimes be difficult to detect and reproduce empirically. When strictly applied, reproducibility is an overstated and even questionable concept in psychological science. Furthermore, statistical measures (e.g., effect size) are poor indicators of the theoretical importance and relevance of phenomena (cf. “deliberate practice” vs. “talent” in expert performance), not to mention whether phenomena are real or unreal. To better understand psychological phenomena, their theoretical and empirical properties should be examined via multiple parameters and criteria. Ten such parameters are suggested. PMID:28626435

Solar Phenomena Associated with "EIT Waves"

NASA Technical Reports Server (NTRS)

Biesecker, D. A.; Myers, D. C.; Thompson, B. J.; Hammer, D. M.; Vourlidas, A.

2002-01-01

In an effort to understand what an 'EIT wave' is and what its causes are, we have looked for correlations between the initiation of EIT waves and the occurrence of other solar phenomena. An EIT wave is a coronal disturbance, typically appearing as a diffuse brightening propagating across the Sun. A catalog of EIT waves, covering the period from 1997 March through 1998 June, was used in this study. For each EIT wave, the catalog gives the heliographic location and a rating for each wave, where the rating is determined by the reliability of the observations. Since EIT waves are transient, coronal phenomena, we have looked for correlations with other transient, coronal phenomena: X-ray flares, coronal mass ejections (CMEs), and metric type II radio bursts. An unambiguous correlation between EIT waves and CMEs has been found. The correlation of EIT waves with flares is significantly weaker, and EIT waves frequently are not accompanied by radio bursts. To search for trends in the data, proxies for each of these transient phenomena are examined. We also use the accumulated data to show the robustness of the catalog and to reveal biases that must be accounted for in this study.

Comprehending emergent systems phenomena through direct-manipulation animation

NASA Astrophysics Data System (ADS)

Aguirre, Priscilla Abel

This study seeks to understand the type of interaction mode that best supports learning and comprehension of emergent systems phenomena. Given that the literature has established that students hold robust misconceptions of such phenomena, this study investigates the influence of using three types of interaction; speed-manipulation animation (SMN), post-manipulation animation (PMA) and direct-manipulation animation (DMA) for increasing comprehension and testing transfer of the phenomena, by looking at the effect of simultaneous interaction of haptic and visual channels on long term and working memories when seeking to comprehend emergent phenomena. The questions asked were: (1) Does the teaching of emergent phenomena, with the aid of a dynamic interactive modeling tool (i.e., SMA, PMA or DMA), improve students' mental model construction of systems, thus increasing comprehension of this scientific concept? And (2) does the teaching of emergent phenomena, with the aid of a dynamic interactive modeling tool, give the students the necessary complex cognitive skill which can then be applied to similar (near transfer) and/or novel, but different, (far transfer) scenarios? In an empirical study undergraduate and graduate students were asked to participate in one of three experimental conditions: SMA, PMA, or DMA. The results of the study found that it was the participants of the SMA treatment condition that had the most improvement in post-test scores. Students' understanding of the phenomena increased most when they used a dynamic model with few interactive elements (i.e., start, stop, and speed) that allowed for real time visualization of one's interaction on the phenomena. Furthermore, no indication was found that the learning of emergent phenomena, with the aid of a dynamic interactive modeling tool, gave the students the necessary complex cognitive skill which could then be applied to similar (near transfer) and/or novel, but different, (far transfer) scenarios

The effect of ventilation strategies of child care centers on indoor air quality and respiratory health of children in Singapore.

PubMed

Zuraimi, M S; Tham, K W; Chew, F T; Ooi, P L

2007-08-01

This paper reports the effects of ventilation strategies on indoor air quality (IAQ) and respiratory health of children within 104 child care centers (CCCs) in a hot and humid climate. The CCCs were categorized by ventilation strategies: natural (NV), air-conditioned and mechanically ventilated (ACMV), air-conditioned using split units (AC), and hybrid (NV and AC operated intermittently). The concentration levels of IAQ parameters in NV CCCs are characterized by the influence of the outdoors and good dilution of indoor pollutants. The lower ventilation rates in air-conditioned CCCs result in higher concentrations of occupant-related pollutants but lower outdoor pollutant ingress. This study also revealed lower prevalence for most asthma and allergy, and respiratory symptoms in children attending NV CCCs. In multivariate analyses controlled for the effects of confounders, the risk of current rhinitis among children is significantly higher if they attend mechanically ventilated CCCs compared to NV CCCs. Air-conditioned CCCs were also associated with higher adjusted prevalence ratio of severe phlegm and cough symptoms and lower respiratory illness. Finally, children attending CCCs with hybrid ventilation are at high risk for almost all the respiratory symptoms studied. This large field study indicates that different ventilation strategies employed by child care centers can cause significant variations in the indoor air quality and prevalence of asthma, allergies and respiratory symptoms of attending children. The higher prevalence rates of allergic and respiratory symptoms among young children, whose immune system is still under-developed, in child care centers, whether fully or partially air-conditioned, suggest that ventilation and plausible growth and propagation mechanisms of allergens and infectious agents be further investigated.

Do Weather Phenomena Have Any Influence on the Occurrence of Spontaneous Pneumothorax?

PubMed

Vodička, Josef; Vejvodová, Šárka; Šmíd, David; Fichtl, Jakub; Špidlen, Vladimír; Kormunda, Stanislav; Hostýnek, Jiří; Moláček, Jiří

2016-05-01

The objective of this study was to assess the impact of weather phenomena on the occurrence of spontaneous pneumothorax (SP) in the Plzeň region (Czech Republic). A retrospective analysis of 450 cases of SP in 394 patients between 1991 and 2013. We observed changes in average daily values of atmospheric pressure, air temperature and daily maximum wind gust for each day of that period and their effect on the development of SP. The risk of developing SP is 1.41 times higher (P=.0017) with air pressure changes of more than±6.1hPa. When the absolute value of the air temperature changes by more than±0.9°C, the risk of developing SP is 1.55 times higher (P=.0002). When the wind speed difference over the 5 days prior to onset of SP is less than 13m/sec, then the risk of SP is 2.16 times higher (P=.0004). If the pressure difference is greater than±6.1hPa and the temperature difference is greater than±0.9°C or the wind speed difference during the 5 days prior to onset of SP is less than 10.7m/s, the risk of SP is 2.04 times higher (P≤.0001). Changes in atmospheric pressure, air temperature and wind speed are undoubtedly involved in the development of SP, but don't seem to be the only factors causing rupture of blebs or emphysematous bullae. Copyright © 2015 SEPAR. Published by Elsevier Espana. All rights reserved.

The relationships between air exposure, negative pressure, and hemolysis.

PubMed

Pohlmann, Joshua R; Toomasian, John M; Hampton, Claire E; Cook, Keith E; Annich, Gail M; Bartlett, Robert H

2009-01-01

The purpose of this study was to describe the hemolytic effects of both negative pressure and an air-blood interface independently and in combination in an in vitro static blood model. Samples of fresh ovine or human blood (5 ml) were subjected to a bubbling air interface (0-100 ml/min) or negative pressure (0-600 mm Hg) separately, or in combination, for controlled periods of time and analyzed for hemolysis. Neither negative pressure nor an air interface alone increased hemolysis. However, when air and negative pressure were combined, hemolysis increased as a function of negative pressure, the air interface, and time. Moreover, when blood samples were exposed to air before initiating the test, hemolysis was four to five times greater than samples not preexposed to air. When these experiments were repeated using freshly drawn human blood, the same phenomena were observed, but the hemolysis was significantly higher than that observed in sheep blood. In this model, hemolysis is caused by combined air and negative pressure and is unrelated to either factor alone.

The Relationships between Air Exposure, Negative Pressure and Hemolysis

PubMed Central

Pohlmann, Joshua R.; Toomasian, John M.; Hampton, Claire E.; Cook, Keith E.; Annich, Gail M.; Bartlett, Robert H.

2013-01-01

The purpose of this study was to describe the hemolytic effects of both negative pressure and an air-blood interface independently and in combination in an in-vitro static blood model. Samples of fresh ovine or human blood (5 mL) were subjected to a bubbling air interface (0–100 mL/min) or negative pressure (0–600 mmHg) separately, or in combination, for controlled periods of time, and analyzed for hemolysis. Neither negative pressure nor an air interface alone increased hemolysis. However, when air and negative pressure were combined, hemolysis increased as a function of negative pressure, the air interface, and time. Moreover, when blood samples were exposed to air prior to initiating the test, hemolysis was 4–5 times greater than samples not pre-exposed to air. When these experiments were repeated using freshly drawn human blood the same phenomena were observed, but the hemolysis was significantly higher than that observed in sheep blood. In this model, hemolysis is caused by combined air and negative pressure and is unrelated to either factor alone. PMID:19730004

Crystal Melting and Wall Crossing Phenomena

NASA Astrophysics Data System (ADS)

Yamazaki, Masahito

This paper summarizes recent developments in the theory of Bogomol'nyi-Prasad-Sommerfield (BPS) state counting and the wall crossing phenomena, emphasizing in particular the role of the statistical mechanical model of crystal melting. This paper is divided into two parts, which are closely related to each other. In the first part, we discuss the statistical mechanical model of crystal melting counting BPS states. Each of the BPS states contributing to the BPS index is in one-to-one correspondence with a configuration of a molten crystal, and the statistical partition function of the melting crystal gives the BPS partition function. We also show that smooth geometry of the Calabi-Yau manifold emerges in the thermodynamic limit of the crystal. This suggests a remarkable interpretation that an atom in the crystal is a discretization of the classical geometry, giving an important clue as such to the geometry at the Planck scale. In the second part, we discuss the wall crossing phenomena. Wall crossing phenomena states that the BPS index depends on the value of the moduli of the Calabi-Yau manifold, and jumps along real codimension one subspaces in the moduli space. We show that by using type IIA/M-theory duality, we can provide a simple and an intuitive derivation of the wall crossing phenomena, furthermore clarifying the connection with the topological string theory. This derivation is consistent with another derivation from the wall crossing formula, motivated by multicentered BPS extremal black holes. We also explain the representation of the wall crossing phenomena in terms of crystal melting, and the generalization of the counting problem and the wall crossing to the open BPS invariants.

Schlieren imaging of loud sounds and weak shock waves in air near the limit of visibility

NASA Astrophysics Data System (ADS)

Hargather, Michael John; Settles, Gary S.; Madalis, Matthew J.

2010-02-01

A large schlieren system with exceptional sensitivity and a high-speed digital camera are used to visualize loud sounds and a variety of common phenomena that produce weak shock waves in the atmosphere. Frame rates varied from 10,000 to 30,000 frames/s with microsecond frame exposures. Sound waves become visible to this instrumentation at frequencies above 10 kHz and sound pressure levels in the 110 dB (6.3 Pa) range and above. The density gradient produced by a weak shock wave is examined and found to depend upon the profile and thickness of the shock as well as the density difference across it. Schlieren visualizations of weak shock waves from common phenomena include loud trumpet notes, various impact phenomena that compress a bubble of air, bursting a toy balloon, popping a champagne cork, snapping a wooden stick, and snapping a wet towel. The balloon burst, snapping a ruler on a table, and snapping the towel and a leather belt all produced readily visible shock-wave phenomena. In contrast, clapping the hands, snapping the stick, and the champagne cork all produced wave trains that were near the weak limit of visibility. Overall, with sensitive optics and a modern high-speed camera, many nonlinear acoustic phenomena in the air can be observed and studied.

Numerical Investigations of Slip Phenomena in Centrifugal Compressor Impellers

NASA Astrophysics Data System (ADS)

Huang, Jeng-Min; Luo, Kai-Wei; Chen, Ching-Fu; Chiang, Chung-Ping; Wu, Teng-Yuan; Chen, Chun-Han

2013-03-01

This study systematically investigates the slip phenomena in the centrifugal air compressor impellers by CFD. Eight impeller blades for different specific speeds, wrap angles and exit blade angles are designed by compressor design software to analyze their flow fields. Except for the above three variables, flow rate and number of blades are the other two. Results show that the deviation angle decreases as the flow rate increases. The specific speed is not an important parameter regarding deviation angle or slip factor for general centrifugal compressor impellers. The slip onset position is closely related to the position of the peak value in the blade loading factor distribution. When no recirculation flow is present at the shroud, the variations of slip factor under various flow rates are mainly determined by difference between maximum blade angle and exit blade angle, Δβmax-2. The solidity should be of little importance to slip factor correlations in centrifugal compressor impellers.

Ambroise August Liébeault and psychic phenomena.

PubMed

Alvarado, Carlos S

2009-10-01

Some nineteenth-century hypnosis researchers did not limit their interest to the study of the conventional psychological and behavioral aspects of hypnosis, but also studied and wrote about psychic phenomena such as mental suggestion and clairvoyance. One example, and the topic of this paper, was French physician Ambroise August Liébeault (1823-1904), who influenced the Nancy school of hypnosis. Liébeault wrote about mental suggestion, clairvoyance, mediumship, and even so-called poltergeists. Some of his writings provide conventional explanations of the phenomena. Still of interest today, Liébeault's writings about psychic phenomena illustrate the overlap that existed during the nineteenth-century between hypnosis and psychic phenomena--an overlap related to the potentials of the mind and its subconscious activity.

Indoor air humidity, air quality, and health - An overview.

PubMed

Wolkoff, Peder

2018-04-01

There is a long-standing dispute about indoor air humidity and perceived indoor air quality (IAQ) and associated health effects. Complaints about sensory irritation in eyes and upper airways are generally among top-two symptoms together with the perception "dry air" in office environments. This calls for an integrated analysis of indoor air humidity and eye and airway health effects. This overview has reviewed the literature about the effects of extended exposure to low humidity on perceived IAQ, sensory irritation symptoms in eyes and airways, work performance, sleep quality, virus survival, and voice disruption. Elevation of the indoor air humidity may positively impact perceived IAQ, eye symptomatology, and possibly work performance in the office environment; however, mice inhalation studies do not show exacerbation of sensory irritation in the airways by low humidity. Elevated humidified indoor air appears to reduce nasal symptoms in patients suffering from obstructive apnea syndrome, while no clear improvement on voice production has been identified, except for those with vocal fatigue. Both low and high RH, and perhaps even better absolute humidity (water vapor), favors transmission and survival of influenza virus in many studies, but the relationship between temperature, humidity, and the virus and aerosol dynamics is complex, which in the end depends on the individual virus type and its physical/chemical properties. Dry and humid air perception continues to be reported in offices and in residential areas, despite the IAQ parameter "dry air" (or "wet/humid air") is semantically misleading, because a sensory organ for humidity is non-existing in humans. This IAQ parameter appears to reflect different perceptions among other odor, dustiness, and possibly exacerbated by desiccation effect of low air humidity. It is salient to distinguish between indoor air humidity (relative or absolute) near the breathing and ocular zone and phenomena caused by moisture

Lean Limit Phenomena

NASA Technical Reports Server (NTRS)

Law, C. K.

1983-01-01

The influence of stretch and preferential diffusion on premixed flame extinction and stability was investigated via two model flame configurations, namely the stagnation flame and the bunsen flame. Using a counterflow burner and a stagnation flow burner with a water-cooled wall, the effect of downstream heat loss on the extinction of a stretched premixed flame investigated for lean and rich propane/air and methane/air mixtures. It was demonstrated that extinction by stretch alone is possible only when the deficient reactant is the less mobile one. When it is the more mobile one, downstream heat loss or incomplete reaction is also needed to achieve extinction. The local extinction of bunsen flame tips and edges of hydrocarbon/air premixtures was investigated using a variety of burners. Results show that, while for both rich propane/air and butane/air mixtures tip opening occurs at a constant fuel equivalence ratio of 1.44 and is therefore independent of the intensity, uniformity, and configuration of the approach flow, for rich methane/air flames burning is intensified at the tip and therefore opening is not possible.

A Connection between Transport Phenomena and Thermodynamics

ERIC Educational Resources Information Center

Swaney, Ross; Bird, R. Byron

2017-01-01

Although students take courses in transport phenomena and thermodynamics, they probably do not ask whether these two subjects are related. Here we give an answer to that question. Specifically we give relationships between the equations of change for total energy, internal energy, and entropy of transport phenomena and key equations of equilibrium…

Paramutation phenomena in plants.

PubMed

Pilu, Roberto

2015-08-01

Paramutation is a particular epigenetic phenomenon discovered in Zea mays by Alexander Brink in the 1950s, and then also found in other plants and animals. Brink coined the term paramutation (from the Greek syllable "para" meaning beside, near, beyond, aside) in 1958, with the aim to differentiate paramutation from mutation. The peculiarity of paramutation with respect to other gene silencing phenomena consists in the ability of the silenced allele (named paramutagenic) to silence the other allele (paramutable) present in trans. The newly silenced (paramutated) allele remains stable in the next generations even after segregation from the paramutagenic allele and acquires paramutagenic ability itself. The inheritance behaviour of these epialleles permits a fast diffusion of a particular gene expression level/phenotype in a population even in the absence of other evolutionary influences, thus breaking the Hardy-Weinberg law. As with other gene silencing phenomena such as quelling in the fungus Neurospora crassa, transvection in Drosophila, co-suppression and virus-induced gene silencing (VIGS) described in transgenic plants and RNA interference (RNAi) in the nematode Caenorhabditis elegans, paramutation occurs without changes in the DNA sequence. So far the molecular basis of paramutation remains not fully understood, although many studies point to the involvement of RNA causing changes in DNA methylation and chromatin structure of the silenced genes. In this review I summarize all paramutation phenomena described in plants, focusing on the similarities and differences between them. Copyright © 2015 Elsevier Ltd. All rights reserved.

The making of extraordinary psychological phenomena.

PubMed

Lamont, Peter

2012-01-01

This article considers the extraordinary phenomena that have been central to unorthodox areas of psychological knowledge. It shows how even the agreed facts relating to mesmerism, spiritualism, psychical research, and parapsychology have been framed as evidence both for and against the reality of the phenomena. It argues that these disputes can be seen as a means through which beliefs have been formulated and maintained in the face of potentially challenging evidence. It also shows how these disputes appealed to different forms of expertise, and that both sides appealed to belief in various ways as part of the ongoing dispute about both the facts and expertise. Finally, it shows how, when a formal Psychology of paranormal belief emerged in the twentieth century, it took two different forms, each reflecting one side of the ongoing dispute about the reality of the phenomena. © 2012 Wiley Periodicals, Inc.

Abnormal pressures as hydrodynamic phenomena

USGS Publications Warehouse

Neuzil, C.E.

1995-01-01

So-called abnormal pressures, subsurface fluid pressures significantly higher or lower than hydrostatic, have excited speculation about their origin since subsurface exploration first encountered them. Two distinct conceptual models for abnormal pressures have gained currency among earth scientists. The static model sees abnormal pressures generally as relict features preserved by a virtual absence of fluid flow over geologic time. The hydrodynamic model instead envisions abnormal pressures as phenomena in which flow usually plays an important role. This paper develops the theoretical framework for abnormal pressures as hydrodynamic phenomena, shows that it explains the manifold occurrences of abnormal pressures, and examines the implications of this approach. -from Author

Illustrations and Supporting Texts for Sound Standing Waves of Air Columns in Pipes in Introductory Physics Textbooks

ERIC Educational Resources Information Center

Zeng, Liang; Smith, Chris; Poelzer, G. Herold; Rodriguez, Jennifer; Corpuz, Edgar; Yanev, George

2014-01-01

In our pilot studies, we found that many introductory physics textbook illustrations with supporting text for sound standing waves of air columns in open-open, open-closed, and closed-closed pipes inhibit student understanding of sound standing wave phenomena due to student misunderstanding of how air molecules move within these pipes. Based on…

Air-Coupled Vibrometry

NASA Astrophysics Data System (ADS)

Döring, D.; Solodov, I.; Busse, G.

Sound and ultrasound in air are the products of a multitude of different processes and thus can be favorable or undesirable phenomena. Development of experimental tools for non-invasive measurements and imaging of airborne sound fields is of importance for linear and nonlinear nondestructive material testing as well as noise control in industrial or civil engineering applications. One possible solution is based on acousto-optic interaction, like light diffraction imaging. The diffraction approach usually requires a sophisticated setup with fine optical alignment barely applicable in industrial environment. This paper focuses on the application of the robust experimental tool of scanning laser vibrometry, which utilizes commercial off-the-shelf equipment. The imaging technique of air-coupled vibrometry (ACV) is based on the modulation of the optical path length by the acoustic pressure of the sound wave. The theoretical considerations focus on the analysis of acousto-optical phase modulation. The sensitivity of the ACV in detecting vibration velocity was estimated as ~1 mm/s. The ACV applications to imaging of linear airborne fields are demonstrated for leaky wave propagation and measurements of ultrasonic air-coupled transducers. For higher-intensity ultrasound, the classical nonlinear effect of the second harmonic generation was measured in air. Another nonlinear application includes a direct observation of the nonlinear air-coupled emission (NACE) from the damaged areas in solid materials. The source of the NACE is shown to be strongly localized around the damage and proposed as a nonlinear "tag" to discern and image the defects.

The Role of Family Phenomena in Posttraumatic Stress in Youth

PubMed Central

Deatrick, Janet A.

2010-01-01

Topic Youth face trauma that can cause posttraumatic stress (PTS). Purpose 1). To identify the family phenomena used in youth PTS research; and 2). Critically examine the research findings regarding the relationship between family phenomena and youth PTS. Sources Systematic literature review in PsycInfo, PILOTS, CINAHL, and MEDLINE. Twenty-six empirical articles met inclusion criteria. Conclusion Measurement of family phenomena included family functioning, support, environment, expressiveness, relationships, cohesion, communication, satisfaction, life events related to family, parental style of influence, and parental bonding. Few studies gave clear conceptualization of family or family phenomena. Empirical findings from the 26 studies indicate inconsistent empirical relationships between family phenomena and youth PTS, though a majority of the prospective studies support a relationship between family phenomena and youth PTS. Future directions for leadership by psychiatric nurses in this area of research and practice are recommended. PMID:21344778

The Outdoor Air Pollution and Brain Health Workshop

PubMed Central

Block, Michelle L.; Elder, Alison; Auten, Rick L.; Bilbo, Staci D.; Chen, Honglei; Chen, Jiu-Chiuan; Cory-Slechta, Deborah A.; Costa, Daniel; Diaz-Sanchez, David; Dorman, David C.; Gold, Diane; Gray, Kimberly; Jeng, Hueiwang Anna; Kaufman, Joel D.; Kleinman, Michael T.; Kirshner, Annette; Lawler, Cindy; Miller, David S.; Nadadur, Sri; Ritz, Beate; Semmens, Erin O.; Tonelli, Leonardo H.; Veronesi, Bellina; Wright, Robert O.; Wright, Rosalind

2013-01-01

Accumulating evidence suggests that outdoor air pollution may have a significant impact on central nervous system (CNS) health and disease. To address this issue, the National Institute of Environmental Health Sciences/National Institute of Health convened a panel of research scientists that was assigned the task of identifying research gaps and priority goals essential for advancing this growing field and addressing an emerging human health concern. Here, we review recent findings that have established the effects of inhaled air pollutants in the brain, explore the potential mechanisms driving these phenomena, and discuss the recommended research priorities/approaches that were identified by the panel. PMID:22981845

Reduplication phenomena: body, mind and archetype.

PubMed

Garner, J

2000-09-01

The many biological and few psychodynamic explanations of reduplicative syndromes tend to have paralleled the dualism of the phenomenon with organic theories concentrating on form and dynamic theories emphasising content. This paper extends the contribution of psychoanalytic thinking to an elucidation of the form of the delusion. Literature on clinical and aetiological aspects of reduplicative phenomena is reviewed alongside a brief examination of psychoanalytic models not overtly related to these phenomena. The human experience of doubles as universal archetype is considered. There is an obvious aetiological role for brain lesions in delusional misidentifications, but psychological symptoms in an individual can rarely be reduced to an organic disorder. The splitting and doubling which occurs in the phenomena have resonances in cultural mythology and in theories from different schools of psychodynamic thought. For the individual patient and doctor, it is a diverting but potentially empty debate to endeavour to draw strict divisions between what is physical and what is psychological although both need to be investigated. Nevertheless, in patients in whom there is clear evidence of an organic contribution to aetiology a psychodynamic understanding may serve to illuminate the patient's experience. Organic brain disease or serious functional illness predispose to regression to earlier modes of archetypical and primitive thinking with concretization of the metaphorical and mythological world. Psychoanalytic models have a contribution in describing the form as well as the content of reduplicative phenomena.

Anomalous Light Phenomena vs. Bioelectric Brain Activity

NASA Astrophysics Data System (ADS)

Teodorani, M.; Nobili, G.

We present a research proposal concerning the instrumented investigation of anomalous light phenomena that are apparently correlated with particular mind states, such as prayer, meditation or psi. Previous research by these authors demonstrate that such light phenomena can be monitored and measured quite efficiently in areas of the world where they are reported in a recurrent way. Instruments such as optical equipment for photography and spectroscopy, VLF spectrometers, magnetometers, radar and IR viewers were deployed and used massively in several areas of the world. Results allowed us to develop physical models concerning the structural and time-variable behaviour of light phenomena, and their kinematics. Recent insights and witnesses have suggested to us that a sort of "synchronous connection" seems to exist between plasma-like phenomena and particular mind states of experiencers who seem to trigger a light manifestation which is very similar to the one previously investigated. The main goal of these authors is now aimed at the search for a concrete "entanglement-like effect" between the experiencer's mind and the light phenomena, in such a way that both aspects are intended to be monitored and measured simultaneously using appropriate instrumentation. The goal of this research project is twofold: a) to verify quantitatively the existence of one very particular kind of mind-matter interaction and to study in real time its physical and biophysical manifestations; b) to repeat the same kind of experiment using the same test-subject in different locations and under various conditions of geomagnetic activity.

Incorporating interfacial phenomena in solidification models

NASA Technical Reports Server (NTRS)

Beckermann, Christoph; Wang, Chao Yang

1994-01-01

A general methodology is available for the incorporation of microscopic interfacial phenomena in macroscopic solidification models that include diffusion and convection. The method is derived from a formal averaging procedure and a multiphase approach, and relies on the presence of interfacial integrals in the macroscopic transport equations. In a wider engineering context, these techniques are not new, but their application in the analysis and modeling of solidification processes has largely been overlooked. This article describes the techniques and demonstrates their utility in two examples in which microscopic interfacial phenomena are of great importance.

Ultrasound-Assisted Hot Air Drying of Foods

NASA Astrophysics Data System (ADS)

Mulet, Antonio; Cárcel, Juan Andrés; García-Pérez, José Vicente; Riera, Enrique

This chapter deals with the application of power ultrasound, also named high-intensity ultrasound, in the hot air drying of foods. The aim of ultrasound-assisted drying is to overcome some of the limitations of traditional convective drying systems, especially by increasing drying rate without reducing quality attributes. The effects of ultrasound on drying rate are responsible for some of the phenomena produced in the internal and/or external resistance to mass transfer.

Geophysical phenomena classification by artificial neural networks

NASA Technical Reports Server (NTRS)

Gough, M. P.; Bruckner, J. R.

1995-01-01

Space science information systems involve accessing vast data bases. There is a need for an automatic process by which properties of the whole data set can be assimilated and presented to the user. Where data are in the form of spectrograms, phenomena can be detected by pattern recognition techniques. Presented are the first results obtained by applying unsupervised Artificial Neural Networks (ANN's) to the classification of magnetospheric wave spectra. The networks used here were a simple unsupervised Hamming network run on a PC and a more sophisticated CALM network run on a Sparc workstation. The ANN's were compared in their geophysical data recognition performance. CALM networks offer such qualities as fast learning, superiority in generalizing, the ability to continuously adapt to changes in the pattern set, and the possibility to modularize the network to allow the inter-relation between phenomena and data sets. This work is the first step toward an information system interface being developed at Sussex, the Whole Information System Expert (WISE). Phenomena in the data are automatically identified and provided to the user in the form of a data occurrence morphology, the Whole Information System Data Occurrence Morphology (WISDOM), along with relationships to other parameters and phenomena.

Antagonistic Phenomena in Network Dynamics

NASA Astrophysics Data System (ADS)

Motter, Adilson E.; Timme, Marc

2018-03-01

Recent research on the network modeling of complex systems has led to a convenient representation of numerous natural, social, and engineered systems that are now recognized as networks of interacting parts. Such systems can exhibit a wealth of phenomena that not only cannot be anticipated from merely examining their parts, as per the textbook definition of complexity, but also challenge intuition even when considered in the context of what is now known in network science. Here, we review the recent literature on two major classes of such phenomena that have far-reaching implications: (a) antagonistic responses to changes of states or parameters and (b) coexistence of seemingly incongruous behaviors or properties - both deriving from the collective and inherently decentralized nature of the dynamics. They include effects as diverse as negative compressibility in engineered materials, rescue interactions in biological networks, negative resistance in fluid networks, and the Braess paradox occurring across transport and supply networks. They also include remote synchronization, chimera states, and the converse of symmetry breaking in brain, power-grid, and oscillator networks as well as remote control in biological and bioinspired systems. By offering a unified view of these various scenarios, we suggest that they are representative of a yet broader class of unprecedented network phenomena that ought to be revealed and explained by future research.

Skating on a Film of Air: Drops Impacting on a Surface

NASA Astrophysics Data System (ADS)

Kolinski, John M.; Rubinstein, Shmuel M.; Mandre, Shreyas; Brenner, Michael P.; Weitz, David A.; Mahadevan, L.

2012-02-01

The commonly accepted description of drops impacting on a surface typically ignores the essential role of the air that is trapped between the impacting drop and the surface. Here we describe a new imaging modality that is sensitive to the behavior right at the surface. We show that a very thin film of air, only a few tens of nanometers thick, remains trapped between the falling drop and the surface as the drop spreads. The thin film of air serves to lubricate the drop enabling the fluid to skate on the air film laterally outward at surprisingly high velocities, consistent with theoretical predictions. Eventually this thin film of air breaks down as the fluid wets the surface via a spinodal-like mechanism. Our results show that the dynamics of impacting drops are much more complex than previously thought, with a rich array of unexpected phenomena that require rethinking classic paradigms.

Thermodynamic constraints on fluctuation phenomena

NASA Astrophysics Data System (ADS)

Maroney, O. J. E.

2009-12-01

The relationships among reversible Carnot cycles, the absence of perpetual motion machines, and the existence of a nondecreasing globally unique entropy function form the starting point of many textbook presentations of the foundations of thermodynamics. However, the thermal fluctuation phenomena associated with statistical mechanics has been argued to restrict the domain of validity of this basis of the second law of thermodynamics. Here we demonstrate that fluctuation phenomena can be incorporated into the traditional presentation, extending rather than restricting the domain of validity of the phenomenologically motivated second law. Consistency conditions lead to constraints upon the possible spectrum of thermal fluctuations. In a special case this uniquely selects the Gibbs canonical distribution and more generally incorporates the Tsallis distributions. No particular model of microscopic dynamics need be assumed.

Thermodynamic constraints on fluctuation phenomena.

PubMed

Maroney, O J E

2009-12-01

The relationships among reversible Carnot cycles, the absence of perpetual motion machines, and the existence of a nondecreasing globally unique entropy function form the starting point of many textbook presentations of the foundations of thermodynamics. However, the thermal fluctuation phenomena associated with statistical mechanics has been argued to restrict the domain of validity of this basis of the second law of thermodynamics. Here we demonstrate that fluctuation phenomena can be incorporated into the traditional presentation, extending rather than restricting the domain of validity of the phenomenologically motivated second law. Consistency conditions lead to constraints upon the possible spectrum of thermal fluctuations. In a special case this uniquely selects the Gibbs canonical distribution and more generally incorporates the Tsallis distributions. No particular model of microscopic dynamics need be assumed.

Collective phenomena in photonic, plasmonic and hybrid structures.

PubMed

Boriskina, Svetlana V; Povinelli, Michelle; Astratov, Vasily N; Zayats, Anatoly V; Podolskiy, Viktor A

2011-10-24

Preface to a focus issue of invited articles that review recent progress in studying the fundamental physics of collective phenomena associated with coupling of confined photonic, plasmonic, electronic and phononic states and in exploiting these phenomena to engineer novel devices for light generation, optical sensing, and information processing. © 2011 Optical Society of America

Utilizing adaptive wing technology in the control of a micro air vehicle

NASA Astrophysics Data System (ADS)

Null, William R.; Wagner, Matthew G.; Shkarayev, Sergey V.; Jouse, Wayne C.; Brock, Keith M.

2002-07-01

Evolution of the design of micro air vehicles (MAVs) towards miniaturization has been severely constrained by the size and mass of the electronic components needed to control the vehicles. Recent research, experimentation, and development in the area of smart materials have led to the possibility of embedding control actuators, fabricated from smart materials, in the wing of the vehicle, reducing both the size and mass of these components. Further advantages can be realized by developing adaptive wing structures. Small size and mass, and low airspeeds, can lead to considerable buffeting during flight, and may result in a loss of flight control. In order to counter these effects, we are developing a thin, variable-cambered airfoil design with actuators embedded within the wing. In addition to reducing the mass and size of the vehicle or, conversely, increasing its available payload, an important benefit from the adaptive wing concept is the possibility of in-flight modification of the flight envelope. Reduced airspeeds, which are crucial during loiter, can be realized by an in-flight increase in wing camber. Conversely, decreases in camber provide for an airframe best suited for rapid ingress/egress and extension of the mission range.

Hemispheric Transport of Air Pollutants: Issues, Progress, and Implications

NASA Astrophysics Data System (ADS)

Keating, T.

2007-12-01

Once thought of as only a local or regional issue, air quality is now understood to be influenced by local, regional, hemispheric, and global phenomena. There is well-documented evidence from ground-, aircraft-, and satellite- based observations for the intercontinental transport of ozone, aerosols, mercury, and some persistent organic pollutants. Global and regional models have provided a range of estimates of the influence of emissions on one continent on concentrations and deposition levels on another continent. These estimates have been difficult to compare and the significance of this intercontinental influence for the design of air pollution control policies is not well understood. The Task Force on Hemispheric Transport of Air Pollutants organized under the Convention on Long-Range Transboundary Air Pollution is developing the first systematic assessment of intercontinental transport and hemispheric pollution in the Northern Hemisphere. This presentation by one of the co-chairs of the Task Force will explore the motivations behind the creation of the Task Force, review its progress, and discuss the implications of its work for the development of domestic and international air quality management policies.

A geophysical shock and air blast simulator at the National Ignition Facility

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

Fournier, K. B.; Brown, C. G.; May, M. J.

2014-09-15

The energy partitioning energy coupling experiments at the National Ignition Facility (NIF) have been designed to measure simultaneously the coupling of energy from a laser-driven target into both ground shock and air blast overpressure to nearby media. The source target for the experiment is positioned at a known height above the ground-surface simulant and is heated by four beams from the NIF. The resulting target energy density and specific energy are equal to those of a low-yield nuclear device. The ground-shock stress waves and atmospheric overpressure waveforms that result in our test system are hydrodynamically scaled analogs of full-scale seismicmore » and air blast phenomena. This report summarizes the development of the platform, the simulations, and calculations that underpin the physics measurements that are being made, and finally the data that were measured. Agreement between the data and simulation of the order of a factor of two to three is seen for air blast quantities such as peak overpressure. Historical underground test data for seismic phenomena measured sensor displacements; we measure the stresses generated in our ground-surrogate medium. We find factors-of-a-few agreement between our measured peak stresses and predictions with modern geophysical computer codes.« less

A geophysical shock and air blast simulator at the National Ignition Facility

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

Fournier, K. B.; Brown, C. G.; May, M. J.

2014-09-01

The energy partitioning energy coupling experiments at the National Ignition Facility (NIF) have been designed to measure simultaneously the coupling of energy from a laser-driven target into both ground shock and air blast overpressure to nearby media. The source target for the experiment is positioned at a known height above the ground-surface simulant and is heated by four beams from the NIF. The resulting target energy density and specific energy are equal to those of a low-yield nuclear device. The ground-shock stress waves and atmospheric overpressure waveforms that result in our test system are hydrodynamically scaled analogs of full-scale seismicmore » and air blast phenomena. This report summarizes the development of the platform, the simulations, and calculations that underpin the physics measurements that are being made, and finally the data that were measured. Agreement between the data and simulation of the order of a factor of two to three is seen for air blast quantities such as peak overpressure. Historical underground test data for seismic phenomena measured sensor displacements; we measure the stresses generated in our ground-surrogate medium. We find factors-of-a-few agreement between our measured peak stresses and predictions with modern geophysical computer codes.« less

Quantum Chess: Making Quantum Phenomena Accessible

NASA Astrophysics Data System (ADS)

Cantwell, Christopher

Quantum phenomena have remained largely inaccessible to the general public. There tends to be a scare factor associated with the word ``Quantum''. This is in large part due to the alien nature of phenomena such as superposition and entanglement. However, Quantum Computing is a very active area of research and one day we will have games that run on those quantum computers. Quantum phenomena such as superposition and entanglement will seem as normal as gravity. Is it possible to create such games today? Can we make games that are built on top of a realistic quantum simulation and introduce players of any background to quantum concepts in a fun and mentally stimulating way? One of the difficulties with any quantum simulation run on a classical computer is that the Hilbert space grows exponentially, making simulations of an appreciable size physically impossible due largely to memory restrictions. Here we will discuss the conception and development of Quantum Chess, and how to overcome some of the difficulties faced. We can then ask the question, ``What's next?'' What are some of the difficulties Quantum Chess still faces, and what is the future of quantum games?

Electrocapillary Phenomena at Edible Oil/Saline Interfaces.

PubMed

Nishimura, Satoshi; Ohzono, Takuya; Shoji, Kohei; Yagihara, Shin; Hayashi, Masafumi; Tanaka, Hisao

2017-03-01

Interfacial tension between edible oil and saline was measured under applied electric fields to understand the electrocapillary phenomena at the edible oil/saline interfaces. The electric responses of saline droplets in edible oil were also observed microscopically to examine the relationship between the electrocapillary phenomena and interfacial polarization. When sodium oleate (SO) was added to edible oil (SO-oil), the interfacial tension between SO-oil and saline decreased. However, no decrease was observed for additive-free oil or oleic acid (OA)-added oil (OA-oil). Microscopic observations suggested that the magnitude of interfacial polarization increased in the order of additive-free oil < OA-oil < SO-oil. The difference in electrocapillary phenomena between OA- and SO-oils was closely related to the polarization magnitude. In the case of SO-oil, the decrease in interfacial tension was remarkably larger for saline (pH 5.4~5.6) than that for phosphate-buffered saline (PBS, pH 7.2~7.4). However, no difference was observed between the electric responses of PBS and saline droplets in SO-oil. The difference in electrocapillary phenomena for PBS and saline could not be simply explained in terms of polarization magnitude. The ratio of ionized and non-ionized OA at the interfaces changed with the saline pH, possibly leading to the above difference.

Evaluation of the operator protection factors offered by positive pressure air suits against airborne microbiological challenge.

PubMed

Steward, Jackie A; Lever, Mark S

2012-08-01

Laboratories throughout the world that perform work with Risk Group 4 Pathogens generally adopt one of two approaches within BSL-4 environments: either the use of positive pressure air-fed suits or using Class III microbiological safety cabinets and isolators for animal work. Within the UK at present, all laboratories working with Risk Group 4 agents adopt the use of Class III microbiological safety cabinet lines and isolators. Operator protection factors for the use of microbiological safety cabinets and isolators are available however; there is limited published data on the operator protection factors afforded by the use of positive pressure suits. This study evaluated the operator protection factors provided by positive pressure air suits against a realistic airborne microbiological challenge. The suits were tested, both intact and with their integrity compromised, on an animated mannequin within a stainless steel exposure chamber. The suits gave operator protection in all tests with an intact suit and with a cut in the leg. When compromised by a cut in the glove, a very small ingress of the challenge was seen as far as the wrist. This is likely to be due to the low airflow in the gloves of the suit. In all cases no microbiological penetration of the respiratory tract was observed. These data provide evidence on which to base safety protocols for use of positive pressure suits within high containment laboratories.

On the accuracy of the rate coefficients used in plasma fluid models for breakdown in air

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

Kourtzanidis, Konstantinos, E-mail: kkourt@utexas.edu; Raja, Laxminarayan L., E-mail: lraja@mail.utexas.edu

2016-07-15

The electrical breakdown of air depends on the balance between creation and loss of charged particles. In fluid models, datasets of the rate coefficients used are obtained either from fits to experimental data or by solutions of the Boltzmann equation. Here, we study the accuracy of the commonly used models for ionization and attachment frequencies and their impact on the prediction of the breakdown threshold for air. We show that large errors can occur depending on the model and propose the most accurate dataset available for modeling of air breakdown phenomena.

Pendulum Phenomena and the Assessment of Scientific Inquiry Capabilities

ERIC Educational Resources Information Center

Zachos, Paul

2004-01-01

Phenomena associated with the "pendulum" present numerous opportunities for assessing higher order human capabilities related to "scientific inquiry" and the "discovery" of natural law. This paper illustrates how systematic "assessment of scientific inquiry capabilities", using "pendulum" phenomena, can provide a useful tool for classroom teachers…

Realistic generation of natural phenomena based on video synthesis

NASA Astrophysics Data System (ADS)

Wang, Changbo; Quan, Hongyan; Li, Chenhui; Xiao, Zhao; Chen, Xiao; Li, Peng; Shen, Liuwei

2009-10-01

Research on the generation of natural phenomena has many applications in special effects of movie, battlefield simulation and virtual reality, etc. Based on video synthesis technique, a new approach is proposed for the synthesis of natural phenomena, including flowing water and fire flame. From the fire and flow video, the seamless video of arbitrary length is generated. Then, the interaction between wind and fire flame is achieved through the skeleton of flame. Later, the flow is also synthesized by extending the video textures using an edge resample method. Finally, we can integrate the synthesized natural phenomena into a virtual scene.

The experimental evidence for parapsychological phenomena: A review.

PubMed

Cardeña, Etzel

2018-05-24

This article presents a comprehensive integration of current experimental evidence and theories about so-called parapsychological (psi) phenomena. Throughout history, people have reported events that seem to violate the common sense view of space and time. Some psychologists have been at the forefront of investigating these phenomena with sophisticated research protocols and theory, while others have devoted much of their careers to criticizing the field. Both stances can be explained by psychologists' expertise on relevant processes such as perception, memory, belief, and conscious and nonconscious processes. This article clarifies the domain of psi, summarizes recent theories from physics and psychology that present psi phenomena as at least plausible, and then provides an overview of recent/updated meta-analyses. The evidence provides cumulative support for the reality of psi, which cannot be readily explained away by the quality of the studies, fraud, selective reporting, experimental or analytical incompetence, or other frequent criticisms. The evidence for psi is comparable to that for established phenomena in psychology and other disciplines, although there is no consensual understanding of them. The article concludes with recommendations for further progress in the field including the use of project and data repositories, conducting multidisciplinary studies with enough power, developing further nonconscious measures of psi and falsifiable theories, analyzing the characteristics of successful sessions and participants, improving the ecological validity of studies, testing how to increase effect sizes, recruiting more researchers at least open to the possibility of psi, and situating psi phenomena within larger domains such as the study of consciousness. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Air cleaning performance of a new environmentally controlled primary crusher operator booth

PubMed Central

Organiscak, J.A.; Cecala, A.B.; Zimmer, J.A.; Holen, B.; Baregi, J.R.

2016-01-01

The National Institute for Occupational Safety and Health (NIOSH) cooperated with 3M Company in the design and testing of a new environmentally controlled primary crusher operator booth at the company’s Wausau granite quarry near Wausau, WI. This quarry had an older crusher booth without a central heating, ventilation and air conditioning (HVAC) system, and without an air filtration and pressurization system. A new replacement operator booth was designed and installed by 3M based on design considerations from past NIOSH research on enclosed cab filtration systems. NIOSH conducted pre-testing of the old booth and post-testing of the new booth to assess the new filtration and pressurization system’s effectiveness in controlling airborne dusts and particulates. The booth’s dust and particulate control effectiveness is described by its protection factor, expressed as a ratio of the outside to inside concentrations measured during testing. Results indicate that the old booth provided negligible airborne respirable dust protection and low particulate protection from the outside environment. The newly installed booth provided average respirable dust protection factors from 2 to 25 over five shifts of dust sampling with occasional worker ingress and egress from the booth, allowing some unfiltered contaminants to enter the enclosure. Shorter-term particle count testing outside and inside the booth under near-steady-state conditions, with no workers entering or exiting the booth, resulted in protection factors from 35 to 127 on 0.3- to 1.0-μm respirable size particulates under various HVAC airflow operating conditions. PMID:26937052

Air cleaning performance of a new environmentally controlled primary crusher operator booth.

PubMed

Organiscak, J A; Cecala, A B; Zimmer, J A; Holen, B; Baregi, J R

2016-02-01

The National Institute for Occupational Safety and Health (NIOSH) cooperated with 3M Company in the design and testing of a new environmentally controlled primary crusher operator booth at the company's Wausau granite quarry near Wausau, WI. This quarry had an older crusher booth without a central heating, ventilation and air conditioning (HVAC) system, and without an air filtration and pressurization system. A new replacement operator booth was designed and installed by 3M based on design considerations from past NIOSH research on enclosed cab filtration systems. NIOSH conducted pre-testing of the old booth and post-testing of the new booth to assess the new filtration and pressurization system's effectiveness in controlling airborne dusts and particulates. The booth's dust and particulate control effectiveness is described by its protection factor, expressed as a ratio of the outside to inside concentrations measured during testing. Results indicate that the old booth provided negligible airborne respirable dust protection and low particulate protection from the outside environment. The newly installed booth provided average respirable dust protection factors from 2 to 25 over five shifts of dust sampling with occasional worker ingress and egress from the booth, allowing some unfiltered contaminants to enter the enclosure. Shorter-term particle count testing outside and inside the booth under near-steady-state conditions, with no workers entering or exiting the booth, resulted in protection factors from 35 to 127 on 0.3- to 1.0-μm respirable size particulates under various HVAC airflow operating conditions.

Thermal transport phenomena in nanoparticle suspensions

NASA Astrophysics Data System (ADS)

Cardellini, Annalisa; Fasano, Matteo; Bozorg Bigdeli, Masoud; Chiavazzo, Eliodoro; Asinari, Pietro

2016-12-01

Nanoparticle suspensions in liquids have received great attention, as they may offer an approach to enhance thermophysical properties of base fluids. A good variety of applications in engineering and biomedicine has been investigated with the aim of exploiting the above potential. However, the multiscale nature of nanosuspensions raises several issues in defining a comprehensive modelling framework, incorporating relevant molecular details and much larger scale phenomena, such as particle aggregation and their dynamics. The objectives of the present topical review is to report and discuss the main heat and mass transport phenomena ruling macroscopic behaviour of nanosuspensions, arising from molecular details. Relevant experimental results are included and properly put in the context of recent observations and theoretical studies, which solved long-standing debates about thermophysical properties enhancement. Major transport phenomena are discussed and in-depth analysis is carried out for highlighting the role of geometrical (nanoparticle shape, size, aggregation, concentration), chemical (pH, surfactants, functionalization) and physical parameters (temperature, density). We finally overview several computational techniques available at different scales with the aim of drawing the attention on the need for truly multiscale predictive models. This may help the development of next-generation nanoparticle suspensions and their rational use in thermal applications.

A new asymptotic method for jump phenomena

NASA Technical Reports Server (NTRS)

Reiss, E. L.

1980-01-01

Physical phenomena involving rapid and sudden transitions, such as snap buckling of elastic shells, explosions, and earthquakes, are characterized mathematically as a small disturbance causing a large-amplitude response. Because of this, standard asymptotic and perturbation methods are ill-suited to these problems. In the present paper, a new method of analyzing jump phenomena is proposed. The principal feature of the method is the representation of the response in terms of rational functions. For illustration, the method is applied to the snap buckling of an elastic arch and to a simple combustion problem.

Light-induced phenomena in one-component gas: The transport phenomena

NASA Astrophysics Data System (ADS)

Chermyaninov, I. V.; Chernyak, V. G.

2016-09-01

The article presents the theory of transport processes in a one-component gas located in the capillary under the action of resonant laser radiation and the temperature and pressure gradients. The expressions for the kinetic coefficients determining heat and mass transport in the gas are obtained on the basis of the modified Boltzmann equations for the excited and unexcited particles. The Onsager reciprocal relations for cross kinetic coefficients are proven for all Knudsen numbers and for any law interaction of gas particles with each other and boundary surface. Light-induced phenomena associated with the possible non-equilibrium stationary states of system are analyzed.

Illustrations and supporting texts for sound standing waves of air columns in pipes in introductory physics textbooks

NASA Astrophysics Data System (ADS)

Zeng, Liang; Smith, Chris; Poelzer, G. Herold; Rodriguez, Jennifer; Corpuz, Edgar; Yanev, George

2014-12-01

In our pilot studies, we found that many introductory physics textbook illustrations with supporting text for sound standing waves of air columns in open-open, open-closed, and closed-closed pipes inhibit student understanding of sound standing wave phenomena due to student misunderstanding of how air molecules move within these pipes. Based on the construct of meaningful learning from cognitive psychology and semiotics, a quasiexperimental study was conducted to investigate the comparative effectiveness of two alternative approaches to student understanding: a traditional textbook illustration approach versus a newly designed air molecule motion illustration approach. Thirty volunteer students from introductory physics classes were randomly assigned to two groups of 15 each. Both groups were administered a presurvey. Then, group A read the air molecule motion illustration handout, and group B read a traditional textbook illustration handout; both groups were administered postsurveys. Subsequently, the procedure was reversed: group B read the air molecule motion illustration handout and group A read the traditional textbook illustration handout. This was followed by a second postsurvey along with an exit research questionnaire. The study found that the majority of students experienced meaningful learning and stated that they understood sound standing wave phenomena significantly better using the air molecule motion illustration approach. This finding provides a method for physics education researchers to design illustrations for abstract sound standing wave concepts, for publishers to improve their illustrations with supporting text, and for instructors to facilitate deeper learning in their students on sound standing waves.

Department of Energy Natural Phenomena Hazards Mitigation Program

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

Murray, R.C.

1993-09-01

This paper will present a summary of past and present accomplishments of the Natural Phenomena Hazards Program that has been ongoing at Lawrence Livermore National Laboratory since 1975. The Natural Phenomena covered includes earthquake; winds, hurricanes, and tornadoes; flooding and precipitation; lightning; and volcanic events. The work is organized into four major areas (1) Policy, requirements, standards, and guidance (2) Technical support, research development, (3) Technology transfer, and (4) Oversight.

A Course on Surface Phenomena.

ERIC Educational Resources Information Center

Woods, Donald R.

1983-01-01

Describes a graduate or senior elective course combining fundamentals of surface phenomena with practical problem-solving structured around a series of case problems. Discusses topics covered and their development through acquiring new knowledge applied to the case problem, practical calculations of solutions, and applications to additional…

Investigation of the mechanism of soft tissue conduction explains several perplexing auditory phenomena.

PubMed

Adelman, Cahtia; Chordekar, Shai; Perez, Ronen; Sohmer, Haim

2014-09-01

Soft tissue conduction (STC) is a recently expounded mode of auditory stimulation in which the clinical bone vibrator delivers auditory frequency vibratory stimuli to skin sites on the head, neck, and thorax. Investigation of the mechanism of STC stimulation has served as a platform for the elucidation of the mechanics of cochlear activation, in general, and to a better understanding of several perplexing auditory phenomena. This review demonstrates that it is likely that the cochlear hair cells can be directly activated at low sound intensities by the fluid pressures initiated in the cochlea; that the fetus in utero, completely enveloped in amniotic fluid, hears by STC; that a speaker hears his/her own voice by air conduction and by STC; and that pulsatile tinnitus is likely due to pulsatile turbulent blood flow producing fluid pressures that reach the cochlea through the soft tissues.

View of Expedition 32 FE Hoshide during HTV3 Ingress

NASA Image and Video Library

2012-07-28

ISS032-E-011406 (28 July 2012) --- Japan Aerospace Exploration Agency (JAXA) astronaut Aki Hoshide, Expedition 32 flight engineer, using a Russian AK-1M absorber, samples the air in the newly attached JAXA H-II Transfer Vehicle (HTV-3) docked to the International Space Station?s Harmony node.

75 FR 64507 - Taking and Importing Marine Mammals; Military Training Activities Conducted Within the Gulf of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-19

... the typical ordnance that may be used in a SINKEX, which may include missiles, bombs, 5'' gunfire, and...)--During an air-to-surface BOMBEX, maritime patrol aircraft (MPA) or F/A-18 deliver free-fall bombs against... ft (914 m) while adhering to designated ingress and egress routes. Typical bomb release altitude is...

AIRES: an Airborne Infra-Red Echelle Spectrometer for SOFIA

NASA Astrophysics Data System (ADS)

Erickson, E. F.; Haas, M. R.; Colgan, S. W. J.; Roellig, T.; Simpson, J. P.; Telesco, C. M.; Pina, R. K.; Young, E. T.; Wolf, J.

1997-12-01

The Stratospheric Observatory for Infrared Astronomy, SOFIA, is a 2.7 meter telescope which is scheduled to begin observations in a Boeing 747 in October 2001. Among other SOFIA science instruments recently selected for development is the facility spectrometer AIRES. AIRES is designed for studies of a broad range of phenomena occuring in the interstellar medium (ISM) which are uniquely enabled by SOFIA. Examples include accretion and outflow in protostars and young stellar objects, the morphology, dynamics, and excitation of neutral and ionized gas at the Galactic center, and the recycling of material to the ISM from evolved stars. Astronomers using AIRES will be able to select any wavelength from 17 to 210 mu m., with corresponding spectral resolving powers ranging from 60,000 to 4000 in less than a minute. This entire wavelength range is important because it contains spectral features, often widely separated in wavelength, which characterize fundamental ISM processes. AIRES will utilize two-dimensional detector arrays and a large echelle grating to achieve spectral imaging with excellent sensitivity and unparalleled angular resolution at these wavelengths. As a facility science instrument, AIRES will provide guest investigators frequent opportunities for far infrared spectroscopic observations when SOFIA begins operations.

Correlated randomness and switching phenomena

NASA Astrophysics Data System (ADS)

Stanley, H. E.; Buldyrev, S. V.; Franzese, G.; Havlin, S.; Mallamace, F.; Kumar, P.; Plerou, V.; Preis, T.

2010-08-01

One challenge of biology, medicine, and economics is that the systems treated by these serious scientific disciplines have no perfect metronome in time and no perfect spatial architecture-crystalline or otherwise. Nonetheless, as if by magic, out of nothing but randomness one finds remarkably fine-tuned processes in time and remarkably fine-tuned structures in space. Further, many of these processes and structures have the remarkable feature of “switching” from one behavior to another as if by magic. The past century has, philosophically, been concerned with placing aside the human tendency to see the universe as a fine-tuned machine. Here we will address the challenge of uncovering how, through randomness (albeit, as we shall see, strongly correlated randomness), one can arrive at some of the many spatial and temporal patterns in biology, medicine, and economics and even begin to characterize the switching phenomena that enables a system to pass from one state to another. Inspired by principles developed by A. Nihat Berker and scores of other statistical physicists in recent years, we discuss some applications of correlated randomness to understand switching phenomena in various fields. Specifically, we present evidence from experiments and from computer simulations supporting the hypothesis that water’s anomalies are related to a switching point (which is not unlike the “tipping point” immortalized by Malcolm Gladwell), and that the bubbles in economic phenomena that occur on all scales are not “outliers” (another Gladwell immortalization). Though more speculative, we support the idea of disease as arising from some kind of yet-to-be-understood complex switching phenomenon, by discussing data on selected examples, including heart disease and Alzheimer disease.

Bion and Tustin: the autistic phenomena.

PubMed

Korbivcher, Celia Fix

2013-08-01

This article examines the implications of the proposal of autistic transformations within the general context of Bion's theory of Transformations. The aim is to confirm the coherence of this proposal of autistic transformations within the overall structure of Bion's theory of Transformations. She examines the relation between emotional links and their negatives, particularly -K. She questions in which of the dimensions of the mind the autistic phenomena are located, the relation between autistic phenomena and beta elements, and where to place them in the Grid. The author tries to form metapsychological support for the incorporation of the autistic area in Bion's theory of Transformations. She argues that, despite the incongruence and imprecision of this incorporation, such autistic phenomena cannot be excluded from the complexus of the human mind and should therefore be accounted for in Bion's transformations. She discusses the idea that the theory of transformations includes the field of the neurosis and psychosis and deals with emotions, whereas the autistic area is dominated by sensations. The author asks how to add the autistic area to Bion's theory. Clinical material of a child for whom the non-psychotic part of the personality predominates and who presents autistic nuclei provides material for the discussion. Copyright © 2013 Institute of Psychoanalysis.

Three-Dimensional Visualization of Interfacial Phenomena Using Confocal Microscopy

NASA Astrophysics Data System (ADS)

Shieh, Ian C.

Surfactants play an integral role in numerous functions ranging from stabilizing the emulsion in a favorite salad dressing to organizing the cellular components that make life possible. We are interested in lung surfactant, which is a mixture of lipids and proteins essential for normal respiration because it modulates the surface tension of the air-liquid interface of the thin fluid lining in the lungs. Through this surface tension modulation, lung surfactant ensures effortless lung expansion and prevents lung collapse during exhalation, thereby effecting proper oxygenation of the bloodstream. The function of lung surfactant, as well as numerous interfacial lipid systems, is not solely dictated by the behavior of materials confined to the two-dimensional interface. Rather, the distributions of materials in the liquid subphase also greatly influence the performance of interfacial films of lung surfactant. Therefore, to better understand the behavior of lung surfactant and other interfacial lipid systems, we require a three-dimensional characterization technique. In this dissertation, we have developed a novel confocal microscopy methodology for investigating the interfacial phenomena of surfactants at the air-liquid interface of a Langmuir trough. Confocal microscopy provides the excellent combination of in situ, fast, three-dimensional visualization of multiple components of the lung surfactant system that other characterization techniques lack. We detail the solutions to the numerous challenges encountered when imaging a dynamic air-liquid interface with a high-resolution technique like confocal microscopy. We then use confocal microscopy to elucidate the distinct mechanisms by which a polyelectrolyte (chitosan) and nonadsorbing polymer (polyethylene glycol) restore the function of lung surfactant under inhibitory conditions mimicking the effects of lung trauma. Beyond this physiological model, we also investigate several one- and two-component interfacial films

The importance of conceptual models in the reactive transport simulation of oxygen ingress in sparsely fractured crystalline rock.

PubMed

Macquarrie, K T B; Mayer, K U; Jin, B; Spiessl, S M

2010-03-01

Redox evolution in sparsely fractured crystalline rocks is a key, and largely unresolved, issue when assessing the geochemical suitability of deep geological repositories for nuclear waste. Redox zonation created by the influx of oxygenated waters has previously been simulated using reactive transport models that have incorporated a variety of processes, resulting in predictions for the depth of oxygen penetration that may vary greatly. An assessment and direct comparison of the various underlying conceptual models are therefore needed. In this work a reactive transport model that considers multiple processes in an integrated manner is used to investigate the ingress of oxygen for both single fracture and fracture zone scenarios. It is shown that the depth of dissolved oxygen migration is greatly influenced by the a priori assumptions that are made in the conceptual models. For example, the ability of oxygen to access and react with minerals in the rock matrix may be of paramount importance for single fracture conceptual models. For fracture zone systems, the abundance and reactivity of minerals within the fractures and thin matrix slabs between the fractures appear to provide key controls on O(2) attenuation. The findings point to the need for improved understanding of the coupling between the key transport-reaction feedbacks to determine which conceptual models are most suitable and to provide guidance for which parameters should be targeted in field and laboratory investigations. Copyright 2009 Elsevier B.V. All rights reserved.

Research into Surface Wave Phenomena in Sedimentary Basins.

DTIC Science & Technology

1981-12-31

150 km of the southerly extension of the Overthrust Belt, 350 km of the Green River Basin paralleling the Uinta Mountains and 150 km across the Front...WEIDLINGER ASSOCIATES O300 SAND HiLL ROAD BUILDING 4, SUITE 245 MENLO PARK, CALIFORNIA 9462 RESEARCH INTO SURFACE WAVE PHENOMENA IN SEDIMENTARY BASINS BY...PARK, CALIFORNIA 94025 ! I RESEARCH INTO SURFACE WAVE PHENOMENA IN SEDIMENTARY BASINS I Dy G.L. Wojcik J. Isenberg F. Ma E. Richardson Prepared for

Visualizing Chemical Phenomena in Microdroplets

ERIC Educational Resources Information Center

Lee, Sunghee; Wiener, Joseph

2011-01-01

Phenomena that occur in microdroplets are described to the undergraduate chemistry community. Droplets having a diameter in the micrometer range can have unique and interesting properties, which arise because of their small size and, especially, their high surface area-to-volume ratio. Students are generally unfamiliar with the characteristics of…

Nanoflares, Spicules, and Other Small-Scale Dynamic Phenomena on the Sun

NASA Technical Reports Server (NTRS)

Klimchuk, James

2010-01-01

There is abundant evidence of highly dynamic phenomena occurring on very small scales in the solar atmosphere. For example, the observed pr operties of many coronal loops can only be explained if the loops are bundles of unresolved strands that are heated impulsively by nanoflares. Type II spicules recently discovered by Hinode are an example of small-scale impulsive events occurring in the chromosphere. The exist ence of these and other small-scale phenomena is not surprising given the highly structured nature of the magnetic field that is revealed by photospheric observations. Dynamic phenomena also occur on much lar ger scales, including coronal jets, flares, and CMEs. It is tempting to suggest that these different phenomena are all closely related and represent a continuous distribution of sizes and energies. However, this is a dangerous over simplification in my opinion. While it is tru e that the phenomena all involve "magnetic reconnection" (the changin g of field line connectivity) in some form, how this occurs depends s trongly on the magnetic geometry. A nanoflare resulting from the interaction of tangled magnetic strands within a confined coronal loop is much different from a major flare occurring at the current sheet form ed when a CME rips open an active region. I will review the evidence for ubiquitous small-scale dynamic phenomena on the Sun and discuss wh y different phenomena are not all fundamentally the same.

Vector analysis of postcardiotomy behavioral phenomena.

PubMed

Caston, J C; Miller, W C; Felber, W J

1975-04-01

The classification of postcardiotomy behavioral phenomena in Figure 1 is proposed for use as a clinical instrument to analyze etiological determinants. The utilization of a vector analysis analogy inherently denies absolutism. Classifications A-P are presented as prototypes of certain ratio imbalances of the metabolic, hemodynamic, environmental, and psychic vectors. Such a system allows for change from one type to another according to the individuality of the patient and the highly specific changes in his clinical presentation. A vector analysis also allows for infinite intermediary ratio imbalances between classification types as a function of time. Thus, postcardiotomy behavioral phenomena could be viewed as the vector summation of hemodynamic, metabolic, environmental, and psychic processes at a given point in time. Elaboration of unknown determinants in this complex syndrome appears to be task for the future.

Wolf-Rayet phenomena

NASA Technical Reports Server (NTRS)

Conti, P. S.

1982-01-01

The properties of stars showing Wolf-Rayet phenomena are outlined along with the direction of future work. Emphasis is placed on the characteristics of W-R spectra. Specifically the following topics are covered: the absolute visual magnitudes; the heterogeneity of WN spectra; the existence of transition type spectra and compositions the mass loss rates; and the existence of very luminous and possibly very massive W-R stars. Also, a brief overview of current understanding of the theoretical aspects of stellar evolution and stellar winds and the various scenarios that have been proposed to understand W-R spectra are included.

Effects of Oxidation on Oxidation-Resistant Graphite

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

Windes, William; Smith, Rebecca; Carroll, Mark

2015-05-01

The Advanced Reactor Technology (ART) Graphite Research and Development Program is investigating doped nuclear graphite grades that exhibit oxidation resistance through the formation of protective oxides on the surface of the graphite material. In the unlikely event of an oxygen ingress accident, graphite components within the VHTR core region are anticipated to oxidize so long as the oxygen continues to enter the hot core region and the core temperatures remain above 400°C. For the most serious air-ingress accident which persists over several hours or days the continued oxidation can result in significant structural damage to the core. Reducing the oxidationmore » rate of the graphite core material during any air-ingress accident would mitigate the structural effects and keep the core intact. Previous air oxidation testing of nuclear-grade graphite doped with varying levels of boron-carbide (B4C) at a nominal 739°C was conducted for a limited number of doped specimens demonstrating a dramatic reduction in oxidation rate for the boronated graphite grade. This report summarizes the conclusions from this small scoping study by determining the effects of oxidation on the mechanical strength resulting from oxidation of boronated and unboronated graphite to a 10% mass loss level. While the B4C additive did reduce mechanical strength loss during oxidation, adding B4C dopants to a level of 3.5% or more reduced the as-fabricated compressive strength nearly 50%. This effectively minimized any benefits realized from the protective film formed on the boronated grades. Future work to infuse different graphite grades with silicon- and boron-doped material as a post-machining conditioning step for nuclear components is discussed as a potential solution for these challenges in this report.« less

Aircraft Weather Mitigation for the Next Generation Air Transportation System

NASA Technical Reports Server (NTRS)

Stough, H. Paul, III

2007-01-01

Atmospheric effects on aviation are described by Mahapatra (1999) as including (1) atmospheric phenomena involving air motion - wind shear and turbulence; (2) hydrometeorological phenomena - rain, snow and hail; (3) aircraft icing; (4) low visibility; and (5) atmospheric electrical phenomena. Aircraft Weather Mitigation includes aircraft systems (e.g. airframe, propulsion, avionics, controls) that can be enacted (by a pilot, automation or hybrid systems) to suppress and/or prepare for the effects of encountered or unavoidable weather or to facilitate a crew operational decision-making process relative to weather. Aircraft weather mitigation can be thought of as a continuum (Figure 1) with the need to avoid all adverse weather at one extreme and the ability to safely operate in all weather conditions at the other extreme. Realistic aircraft capabilities fall somewhere between these two extremes. The capabilities of small general aviation aircraft would be expected to fall closer to the "Avoid All Adverse Weather" point, and the capabilities of large commercial jet transports would fall closer to the "Operate in All Weather Conditions" point. The ability to safely operate in adverse weather conditions is dependent upon the pilot s capabilities (training, total experience and recent experience), the airspace in which the operation is taking place (terrain, navigational aids, traffic separation), the capabilities of the airport (approach guidance, runway and taxiway lighting, availability of air traffic control), as well as the capabilities of the airplane. The level of mitigation may vary depending upon the type of adverse weather. For example, a small general aviation airplane may be equipped to operate "in the clouds" without outside visual references, but not be equipped to prevent airframe ice that could be accreted in those clouds.

Water gate array for current flow or tidal movement pneumatic harnessing system

DOEpatents

Gorlov, Alexander M.

1991-01-01

The invention, which provides a system for harnessing power from current flow or tidal movement in a body of water, comprises first and second hydro-pneumatic chambers each having ingress and egress below the water surface near the river or ocean floor and water gates operative to open or seal the ports to the passage of water. In an exemplary embodiment, the gates are sychronized by shafts so that the ingress ports of each chamber are connected to the egress ports of each other chamber. Thus, one set of gates is closed, while the other is open, thereby allowing water to flow into one chamber and build air pressure therein and allowing water to flow out of the other chamber and create a partial vacuum therein. A pipe connects the chambers, and an air turbine harnesses the air movement within the pipe. When water levels are equilibrated, the open set of gates is closed by a counterweight, and the other set is allowed to open by natural force of the water differential. The water gates may be comprised of a plurality of louvers which are ganged for simultaneous opening and closing. The system is designed to operate with air turbines or other pneumatic devices. Its design minimizes construction cost and environmental impact, yet provides a clean renewable energy source.

Transport phenomena in porous media

NASA Astrophysics Data System (ADS)

Bear, Jacob; Corapcioglu, M. Yavuz

The Advanced Study Institute on Fundamentals of Transport Phenomena in Porous Media, held July 14-23, 1985 in Newark, Del. and directed by Jacob Bear (Israel Institute of Technology, Haifa) and M. Yavuz Corapcioglu (City College of New York), under the auspices of NATO, was a sequel to the NATO Advanced Study Institute (ASI) held in 1982 (proceedings published as Fundamentals of Transport Phenomena in Porous Media, J. Bear, and M.Y. Corapcioglu (Ed.), Martinus Nijhoff, Dordrecht, the Netherlands, 1984). The meeting was attended by 106 participants and lecturers from 21 countries.As in the first NATO/ASI, the objective of this meeting—which was a combination of a conference of experts and a teaching institute— was to present and discuss selected topics of transport in porous media. In selecting topics and lecturers, an attempt was made to bridge the gap that sometimes exists between research and practice. An effort was also made to demonstrate the unified approach to the transport of mass of a fluid phase, components of a fluid phase, momentum, and heat in a porous medium domain. The void space may be occupied by a single fluid phase or by a number of such phases; each fluid may constitute a multicomponent system; the solid matrix may be deformable; and the whole process of transport in the system may take place under nonisothermal conditions, with or without phase changes. Such phenomena are encountered in a variety of disciplines, e.g., petroleum engineering, civil engineering (in connection with groundwater flow and contamination), soil mechanics, and chemical engineering. One of the goals of the 1985 NATO/ASI, as in the 1982 institute, was to bring together experts from all these disciplines and enhance communication among them.

Membrane Transport Phenomena (MTP)

NASA Technical Reports Server (NTRS)

Mason, Larry W.

1997-01-01

The third semi-annual period of the MTP project has been involved with performing experiments using the Membrane Transport Apparatus (MTA), development of analysis techniques for the experiment results, analytical modeling of the osmotic transport phenomena, and completion of a DC-9 microgravity flight to test candidate fluid cell geometries. Preparations were also made for the MTP Science Concept Review (SCR), held on 13 June 1997 at Lockheed Martin Astronautics in Denver. These activities are detailed in the report.

Eighty phenomena about the self: representation, evaluation, regulation, and change

PubMed Central

Thagard, Paul; Wood, Joanne V.

2015-01-01

We propose a new approach for examining self-related aspects and phenomena. The approach includes (1) a taxonomy and (2) an emphasis on multiple levels of mechanisms. The taxonomy categorizes approximately eighty self-related phenomena according to three primary functions involving the self: representing, effecting, and changing. The representing self encompasses the ways in which people depict themselves, either to themselves or to others (e.g., self-concepts, self-presentation). The effecting self concerns ways in which people facilitate or limit their own traits and behaviors (e.g., self-enhancement, self-regulation). The changing self is less time-limited than the effecting self; it concerns phenomena that involve lasting alterations in how people represent and control themselves (e.g., self-expansion, self-development). Each self-related phenomenon within these three categories may be examined at four levels of interacting mechanisms (social, individual, neural, and molecular). We illustrate our approach by focusing on seven self-related phenomena. PMID:25870574

Respirable particulate monitoring with remote sensors. (Public health ecology: Air pollution)

NASA Technical Reports Server (NTRS)

Severs, R. K.

1974-01-01

The feasibility of monitoring atmospheric aerosols in the respirable range from air or space platforms was studied. Secondary reflectance targets were located in the industrial area and near Galveston Bay. Multichannel remote sensor data were utilized to calculate the aerosol extinction coefficient and thus determine the aerosol size distribution. Houston Texas air sampling network high volume data were utilized to generate computer isopleth maps of suspended particulates and to establish the mass loading of the atmosphere. In addition, a five channel nephelometer and a multistage particulate air sampler were used to collect data. The extinction coefficient determined from remote sensor data proved more representative of wide areal phenomena than that calculated from on site measurements. It was also demonstrated that a significant reduction in the standard deviation of the extinction coefficient could be achieved by reducing the bandwidths used in remote sensor.

CONFERENCES AND SYMPOSIA: Long-lived light phenomena in the atmosphere

NASA Astrophysics Data System (ADS)

Smirnov, Boris M.

1994-05-01

The state of knowledge of long-lived light phenomena in the atmosphere is reviewed in the light of contributions to the International Interdisciplinary Congress on Unsolved Problems of Atmospheric Electricity, September 1993, Salzburg, Austria; and the First International Workshop on Unidentified Atmospheric Light Phenomena, March 1994, Hessdalen, Norway.

COMIS -- an international multizone air-flow and contaminant transport model

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

Feustel, H.E.

1998-08-01

A number of interzonal models have been developed to calculate air flows and pollutant transport mechanisms in both single and multizone buildings. A recent development in multizone air-flow modeling, the COMIS model, has a number of capabilities that go beyond previous models, much as COMIS can be used as either a stand-alone air-flow model with input and output features or as an infiltration module for thermal building simulation programs. COMIS was designed during a 12 month workshop at Lawrence Berkeley National Laboratory (LBNL) in 1988-89. In 1990, the Executive Committee of the International Energy Agency`s Energy Conservation in Buildings andmore » Community Systems program created a working group on multizone air-flow modeling, which continued work on COMIS. The group`s objectives were to study physical phenomena causing air flow and pollutant (e.g., moisture) transport in multizone buildings, develop numerical modules to be integrated in the previously designed multizone air flow modeling system, and evaluate the computer code. The working group supported by nine nations, officially finished in late 1997 with the release of IISiBat/COMIS 3.0, which contains the documented simulation program COMIS, the user interface IISiBat, and reports describing the evaluation exercise.« less

Bubble-induced skin-friction drag reduction and the abrupt transition to air-layer drag reduction

NASA Astrophysics Data System (ADS)

Elbing, Brian R.; Winkel, Eric S.; Lay, Keary A.; Ceccio, Steven L.; Dowling, David R.; Perlin, Marc

To investigate the phenomena of skin-friction drag reduction in a turbulent boundary layer (TBL) at large scales and high Reynolds numbers, a set of experiments has been conducted at the US Navy's William B. Morgan Large Cavitation Channel (LCC). Drag reduction was achieved by injecting gas (air) from a line source through the wall of a nearly zero-pressure-gradient TBL that formed on a flat-plate test model that was either hydraulically smooth or fully rough. Two distinct drag-reduction phenomena were investigated; bubble drag reduction (BDR) and air-layer drag reduction (ALDR).The streamwise distribution of skin-friction drag reduction was monitored with six skin-friction balances at downstream-distance-based Reynolds numbers to 220 million and at test speeds to 20.0msinitial zone1. These results indicated that there are three distinct regions associated with drag reduction with air injection: Region I, BDR; Region II, transition between BDR and ALDR; and Region III, ALDR. In addition, once ALDR was established: friction drag reduction in excess of 80% was observed over the entire smooth model for speeds to 15.3ms1 with the surface fully roughened (though approximately 50% greater volumetric air flux was required); and ALDR was sensitive to the inflow conditions. The sensitivity to the inflow conditions can be mitigated by employing a small faired step (10mm height in the experiment) that helps to create a fixed separation line.

Air Quality Effects on Human Health and Approaches for Its Assessment through Microfluidic Chips.

PubMed

Schulze, Frank; Gao, Xinghua; Virzonis, Darius; Damiati, Samar; Schneider, Marlon R; Kodzius, Rimantas

2017-09-27

Air quality depends on the various gases and particles present in it. Both natural phenomena and human activities affect the cleanliness of air. In the last decade, many countries experienced an unprecedented industrial growth, resulting in changing air quality values, and correspondingly, affecting our life quality. Air quality can be accessed by employing microchips that qualitatively and quantitatively determine the present gases and dust particles. The so-called particular matter 2.5 (PM2.5) values are of high importance, as such small particles can penetrate the human lung barrier and enter the blood system. There are cancer cases related to many air pollutants, and especially to PM2.5, contributing to exploding costs within the healthcare system. We focus on various current and potential future air pollutants, and propose solutions on how to protect our health against such dangerous substances. Recent developments in the Organ-on-Chip (OoC) technology can be used to study air pollution as well. OoC allows determination of pollutant toxicity and speeds up the development of novel pharmaceutical drugs.

Air Quality Effects on Human Health and Approaches for Its Assessment through Microfluidic Chips

PubMed Central

Gao, Xinghua; Virzonis, Darius; Damiati, Samar; Schneider, Marlon R.

2017-01-01

Air quality depends on the various gases and particles present in it. Both natural phenomena and human activities affect the cleanliness of air. In the last decade, many countries experienced an unprecedented industrial growth, resulting in changing air quality values, and correspondingly, affecting our life quality. Air quality can be accessed by employing microchips that qualitatively and quantitatively determine the present gases and dust particles. The so-called particular matter 2.5 (PM2.5) values are of high importance, as such small particles can penetrate the human lung barrier and enter the blood system. There are cancer cases related to many air pollutants, and especially to PM2.5, contributing to exploding costs within the healthcare system. We focus on various current and potential future air pollutants, and propose solutions on how to protect our health against such dangerous substances. Recent developments in the Organ-on-Chip (OoC) technology can be used to study air pollution as well. OoC allows determination of pollutant toxicity and speeds up the development of novel pharmaceutical drugs. PMID:28953246

Unstart phenomena induced by flow choking in scramjet inlet-isolators

NASA Astrophysics Data System (ADS)

Im, Seong-kyun; Do, Hyungrok

2018-02-01

A review of recent research outcomes in downstream flow choking-driven unstart is presented. Unstart is a flow phenomenon at the inlet that severely reduces the air mass flow rate through the engine, causing a loss of thrust and considerable transient mechanical loading. Therefore, unstart in a scramjet engine crucially affects the design and the operation range of hypersonic vehicles. Downstream flow choking is known to be one of the major mechanisms inducing inlet unstart, as confirmed by recent scramjet-powered flight tests. The current paper examines recent research progress in identifying flow choking mechanisms that trigger unstart. Three different flow choking mechanisms are discussed: flow blockage, mass addition, and heat release from combustion reactions. Current research outcomes on the characteristic of unstarting flows, such as transient and quasi-steady motions, are reviewed for each flow choking mechanism. The characteristics of unstarted flows are described including Buzzing phenomena and oscillatory motions of unstarted shockwaves. Then, the state-of-the-art methods to predict, detect, and control unstart are presented. The review suggests that further investigations with high-enthalpy ground facilities will aid understanding of heat release-driven unstart.

Investigation of Hypervelocity Impact Phenomena Using Real-Time Concurrent Diagnostics

NASA Astrophysics Data System (ADS)

Mihaly, Jonathan Michael

Hypervelocity impact of meteoroids and orbital debris poses a serious and growing threat to spacecraft. To study hypervelocity impact phenomena, a comprehensive ensemble of real-time concurrently operated diagnostics has been developed and implemented in the Small Particle Hypervelocity Impact Range (SPHIR) facility. This suite of simultaneously operated instrumentation provides multiple complementary measurements that facilitate the characterization of many impact phenomena in a single experiment. The investigation of hypervelocity impact phenomena described in this work focuses on normal impacts of 1.8 mm nylon 6/6 cylinder projectiles and variable thickness aluminum targets. The SPHIR facility two-stage light-gas gun is capable of routinely launching 5.5 mg nylon impactors to speeds of 5 to 7 km/s. Refinement of legacy SPHIR operation procedures and the investigation of first-stage pressure have improved the velocity performance of the facility, resulting in an increase in average impact velocity of at least 0.57 km/s. Results for the perforation area indicate the considered range of target thicknesses represent multiple regimes describing the non-monotonic scaling of target perforation with decreasing target thickness. The laser side-lighting (LSL) system has been developed to provide ultra-high-speed shadowgraph images of the impact event. This novel optical technique is demonstrated to characterize the propagation velocity and two-dimensional optical density of impact-generated debris clouds. Additionally, a debris capture system is located behind the target during every experiment to provide complementary information regarding the trajectory distribution and penetration depth of individual debris particles. The utilization of a coherent, collimated illumination source in the LSL system facilitates the simultaneous measurement of impact phenomena with near-IR and UV-vis spectrograph systems. Comparison of LSL images to concurrent IR results indicates two

Loads Produced During the Ingression and Egression of the Portable Foot Restraint on the Hubble Space Telescope

NASA Technical Reports Server (NTRS)

Ramsey, Susan; Rajulu, Sudhakar

2000-01-01

The Hubble Space Telescope (HST) was deployed from the Space Shuttle Discovery on April 25, 1990. It is capable of performing observations in the visible, near-ultraviolet, and near-infrared (1150 A to 1 mm). The HST weighs 12 tons, and collects light with an 8-ft-diameter mirror. The attitude control and maneuvering is performed by four of six gyroscopes, or reaction wheels. The HST contains fine guidance sensors that lock onto guide stars to reduce the spacecraft drift and increase the pointing accuracy. The HST was designed to last 15 years, with crewed service missions approximately every three years. The first service mission, STS-61, took place in 1993. The second service mission took place in 1997. In 1999, the STS-103 crew performed the third service mission to the HST. This mission's purpose was to replace the right sensor units and make improvements on the fine guidance sensors. To perform these tasks on the HST, the STS-103 crewmembers used a portable foot restraint to anchor themselves to the HST in the zero-gravity environment. The solar arrays currently used on the telescope are second-generation, and therefore susceptible to loads placed on the telescope. The crew and Mission Operations Directorate worried about the damage that the crew could possibly cause during ingress and egress of the PFR and by transferring loads to the solar arrays. The purpose of this study is to inform the crewmembers of the loads they are imparting on the HST, and train them to decrease these loads to a safer level. Minimizing these loads will significantly decrease the chance of crewmembers causing damage to the solar arrays while repairing the HST.

Observational data needs for plasma phenomena

NASA Technical Reports Server (NTRS)

Niedner, M. B., Jr.

1981-01-01

Bright comets display a rich variety of interesting plasma phenomena which occur over an enormous range of spatial scales, and which require different observational techniques to be studied effectively. Wide-angle photography of high time resolution is probably the best method of studying the phenomenon of largest known scale: the plasma tail disconnection event (DE), which has been attributed to magnetic reconnection at interplanetary sector boundary crossings. These structures usually accelerate as they recede from the head region and observed velocities are typically in the range 50 V km/s. They are often visible for several days following the time of disconnection, and are sometimes seen out past 0.2 AU from the cometary head. The following areas pertaining to plasma phenomena in the ionoshere are addressed: the existence, size, and heliocentric distance variations of the contact surface, and the observational signatures of magnetic reconnection at sector boundary crossings.

Resistive switching phenomena: A review of statistical physics approaches

DOE PAGES

Lee, Jae Sung; Lee, Shinbuhm; Noh, Tae Won

2015-08-31

Here we report that resistive switching (RS) phenomena are reversible changes in the metastable resistance state induced by external electric fields. After discovery ~50 years ago, RS phenomena have attracted great attention due to their potential application in next-generation electrical devices. Considerable research has been performed to understand the physical mechanisms of RS and explore the feasibility and limits of such devices. There have also been several reviews on RS that attempt to explain the microscopic origins of how regions that were originally insulators can change into conductors. However, little attention has been paid to the most important factor inmore » determining resistance: how conducting local regions are interconnected. Here, we provide an overview of the underlying physics behind connectivity changes in highly conductive regions under an electric field. We first classify RS phenomena according to their characteristic current–voltage curves: unipolar, bipolar, and threshold switchings. Second, we outline the microscopic origins of RS in oxides, focusing on the roles of oxygen vacancies: the effect of concentration, the mechanisms of channel formation and rupture, and the driving forces of oxygen vacancies. Third, we review RS studies from the perspective of statistical physics to understand connectivity change in RS phenomena. We discuss percolation model approaches and the theory for the scaling behaviors of numerous transport properties observed in RS. Fourth, we review various switching-type conversion phenomena in RS: bipolar-unipolar, memory-threshold, figure-of-eight, and counter-figure-of-eight conversions. Finally, we review several related technological issues, such as improvement in high resistance fluctuations, sneak-path problems, and multilevel switching problems.« less

Diffusion phenomena of cells and biomolecules in microfluidic devices.

PubMed

Yildiz-Ozturk, Ece; Yesil-Celiktas, Ozlem

2015-09-01

Biomicrofluidics is an emerging field at the cross roads of microfluidics and life sciences which requires intensive research efforts in terms of introducing appropriate designs, production techniques, and analysis. The ultimate goal is to deliver innovative and cost-effective microfluidic devices to biotech, biomedical, and pharmaceutical industries. Therefore, creating an in-depth understanding of the transport phenomena of cells and biomolecules becomes vital and concurrently poses significant challenges. The present article outlines the recent advancements in diffusion phenomena of cells and biomolecules by highlighting transport principles from an engineering perspective, cell responses in microfluidic devices with emphases on diffusion- and flow-based microfluidic gradient platforms, macroscopic and microscopic approaches for investigating the diffusion phenomena of biomolecules, microfluidic platforms for the delivery of these molecules, as well as the state of the art in biological applications of mammalian cell responses and diffusion of biomolecules.

Plasma channel localisation during multiple filamentation in air

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

Panov, N A; Kosareva, O G; Kandidov, V P

It is shown by numerical simulations that multiple filamentation of a femtosecond laser pulse with a negative initial phase modulation in air leads to an increase in the density of self-induced laser plasma compared to the case when a transform-limited laser pulse of the same duration is used. Simultaneous control of the duration of the chirped pulse and the beam diameter results in an increase in the distance over which the first filament is formed, the length of the plasma channel, and its linear density. (nonlinear optical phenomena)

New Phenomena in NC Field Theory and Emergent Spacetime Geometry

NASA Astrophysics Data System (ADS)

Ydri, Badis

2010-10-01

We give a brief review of two nonperturbative phenomena typical of noncommutative field theory which are known to lead to the perturbative instability known as the UV-IR mixing. The first phenomena concerns the emergence/evaporation of spacetime geometry in matrix models which describe perturbative noncommutative gauge theory on fuzzy backgrounds. In particular we show that the transition from a geometrical background to a matrix phase makes the description of noncommutative gauge theory in terms of fields via the Weyl map only valid below a critical value g*. The second phenomena concerns the appearance of a nonuniform ordered phase in noncommutative scalar φ4 field theory and the spontaneous symmetry breaking of translational/rotational invariance which happens even in two dimensions. We argue that this phenomena also originates in the underlying matrix degrees of freedom of the noncommutative field theory. Furthermore it is conjectured that in addition to the usual WF fixed point at θ = 0 there must exist a novel fixed point at θ = ∞ corresponding to the quartic hermitian matrix model.

Critical phenomena on k -booklets

NASA Astrophysics Data System (ADS)

Grassberger, Peter

2017-01-01

We define a "k -booklet" to be a set of k semi-infinite planes with -∞ phenomena: self-avoiding random walks, the Ising model, and percolation. For k =2 , a booklet is equivalent to a single infinite lattice, and for k =1 to a semi-infinite lattice. In both these cases the systems show standard critical phenomena. This is not so for k ≥3 . Self-avoiding walks starting at y =0 show a first-order transition at a shifted critical point, with no power-behaved scaling laws. The Ising model and percolation show hybrid transitions, i.e., the scaling laws of the standard models coexist with discontinuities of the order parameter at y ≈0 , and the critical points are not shifted. In the case of the Ising model, ergodicity is already broken at T =Tc , and not only for T

Calcium contained tap water phenomena: students misconception patterns of acids-bases concept

NASA Astrophysics Data System (ADS)

Liliasari, S.; Albaiti, A.; Wahyudi, A.

2018-05-01

Acids and bases concept is very important and fundamental concept in learning chemistry. It is one of the chemistry subjects considered as an abstract and difficult concept to understand. The aim of this research was to explore student’s misconception pattern about acids and bases phenomena in daily life, such as calcium contained tap water. This was a qualitative research with descriptive methods. Participants were 546 undergraduate students of chemistry education and chemistry program, and graduate students of chemistry education in West Java, Indonesia. The test to explore students’ misconception about this phenomena was essay test. The results showed that there were five patterns of students’ misconception in explaining the phenomena of calcium carbonate precipitation on heating tap water. Students used irrelevant concepts in explaining this phenomena, i.e. temporary hardness, coagulation, density, and phase concepts. No students had right answer in explaining this phenomena. This research contributes to design meaningful learning and to achieve better understanding.

Foot morphometric phenomena.

PubMed

Agić, Ante

2007-06-01

Knowledge of the foot morphometry is important for proper foot structure and function. Foot structure as a vital part of human body is important for many reasons. The foot anthropometric and morphology phenomena are analyzed together with hidden biomechanical descriptors in order to fully characterize foot functionality. For Croatian student population the scatter data of the individual foot variables were interpolated by multivariate statistics. Foot morphometric descriptors are influenced by many factors, such as life style, climate, and things of great importance in human society. Dominant descriptors related to fit and comfort are determined by the use 3D foot shape and advanced foot biomechanics. Some practical recommendations and conclusions for medical, sportswear and footwear practice are highlighted.

Thermal Wave Phenomena

NASA Technical Reports Server (NTRS)

1999-01-01

This map from the MGS Horizon Sensor Assembly (HORSE) shows middle atmospheric temperatures near the 1 mbar level of Mars between Ls 170 to 175 (approx. July 14 - 23, 1999). Local Mars times between 1:30 and 4:30 AM are included. Infrared radiation measured by the Mars Horizon Sensor Assembly was used to make the map. That device continuously views the 'limb' of Mars in four directions, to help orient the spacecraft instruments to the nadir: straight down.

The map shows thermal wave phenomena that are caused by the large topographic variety of Mars' surface, as well the latitudinally symmetric behavior expected at this time of year near the equinox.

Visualization of solidification front phenomena

NASA Technical Reports Server (NTRS)

Workman, Gary L.; Smith, Guy A.

1993-01-01

Directional solidification experiments have been utilized throughout the Materials Processing in Space Program to provide an experimental platform which minimizes variables in solidification experiments. Because of the wide-spread use of this experimental technique in space-based research, it has become apparent that a better understanding of all the phenomena occurring during solidification can be better understood if direct visualization of the solidification interface were possible.

Characterization of Air and Ground Temperature Relationships within the CMIP5 Historical and Future Climate Simulations

NASA Astrophysics Data System (ADS)

García-García, A.; Cuesta-Valero, F. J.; Beltrami, H.; Smerdon, J. E.

2017-12-01

The relationships between air and ground surface temperatures across North America are examined in the historical and future projection simulations from 32 General Circulation Models (GCMs) included in the fifth phase of the Coupled Model Intercomparison Project (CMIP5). The covariability between surface air (2 m) and ground surface temperatures (10 cm) is affected by simulated snow cover, vegetation cover and precipitation through changes in soil moisture at the surface. At high latitudes, the differences between air and ground surface temperatures, for all CMIP5 simulations, are related to the insulating effect of snow cover and soil freezing phenomena. At low latitudes, the differences between the two temperatures, for the majority of simulations, are inversely proportional to leaf area index and precipitation, likely due to induced-changes in latent and sensible heat fluxes at the ground surface. Our results show that the transport of energy across the air-ground interface differs from observations and among GCM simulations, by amounts that depend on the components of the land-surface models that they include. The large variability among GCMs and the marked dependency of the results on the choice of the land-surface model, illustrate the need for improving the representation of processes controlling the coupling of the lower atmosphere and the land surface in GCMs as a means of reducing the variability in their representation of weather and climate phenomena, with potentially important implications for positive climate feedbacks such as permafrost and soil carbon stability.

Understanding cathode flooding and dry-out for water management in air breathing PEM fuel cells

NASA Astrophysics Data System (ADS)

Paquin, Mathieu; Fréchette, Luc G.

An analysis of water management in air breathing small polymer electrolyte membrane fuel cells (PEMFCs) is presented. Comprehensive understanding of flooding and dry-out limiting phenomena is presented through a combination of analytical modeling and experimental investigations using a small PEMFC prototype. Configurations of the fuel cell with different heat and mass transfer properties are experimentally evaluated to assess the impact of thermal resistance and mass transport resistance on water balance. Manifestation of dry-out and flooding problems, as limiting phenomena, are explained through a ratio between these two resistances. Main conclusions are that decreasing the ratio between thermal and mass transport resistance under a certain point leads to flooding problems in air breathing PEMFC. Increasing this ratio leads to dry-out of the polymer electrolyte membrane. However, too high thermal resistance or too low mass transport resistance reduces the limiting current by pushing forward the dry-out problem. This work provides a framework to achieve the proper balance between thermal rejection and mass transport to optimize the maximum current density of free convection fuel cells.

Diffusion phenomena of cells and biomolecules in microfluidic devices

PubMed Central

Yildiz-Ozturk, Ece; Yesil-Celiktas, Ozlem

2015-01-01

Biomicrofluidics is an emerging field at the cross roads of microfluidics and life sciences which requires intensive research efforts in terms of introducing appropriate designs, production techniques, and analysis. The ultimate goal is to deliver innovative and cost-effective microfluidic devices to biotech, biomedical, and pharmaceutical industries. Therefore, creating an in-depth understanding of the transport phenomena of cells and biomolecules becomes vital and concurrently poses significant challenges. The present article outlines the recent advancements in diffusion phenomena of cells and biomolecules by highlighting transport principles from an engineering perspective, cell responses in microfluidic devices with emphases on diffusion- and flow-based microfluidic gradient platforms, macroscopic and microscopic approaches for investigating the diffusion phenomena of biomolecules, microfluidic platforms for the delivery of these molecules, as well as the state of the art in biological applications of mammalian cell responses and diffusion of biomolecules. PMID:26180576

Air shower detectors in gamma-ray astronomy

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

Sinnis, Gus

2008-01-01

Extensive air shower (EAS) arrays directly detect the particles in an EAS that reach the observation altitude. This detection technique effectively makes air shower arrays synoptic telescopes -- they are capable of simultaneously and continuously viewing the entire overhead sky. Typical air shower detectors have an effective field-of-view of 2 sr and operate nearly 100% of the time. These two characteristics make them ideal instruments for studying the highest energy gamma rays, extended sources and transient phenomena. Until recently air shower arrays have had insufficient sensitivity to detect gamma-ray sources. Over the past decade, the situation has changed markedly. Milagro,more » in the US, and the Tibet AS{gamma} array in Tibet, have detected very-high-energy gamma-ray emission from the Crab Nebula and the active galaxy Markarian 421 (both previously known sources). Milagro has discovered TeV diffuse emission from the Milky Way, three unidentified sources of TeV gamma rays, and several candidate sources of TeV gamma rays. Given these successes and the suite of existing and planned instruments in the GeV and TeV regime (AGILE, GLAST, HESS, VERITAS, CTA, AGIS and IceCube) there are strong reasons for pursuing a next generation of EAS detectors. In conjunction with these other instruments the next generation of EAS instruments could answer long-standing problems in astrophysics.« less

Comparison of the light-flash phenomena observed in space and in laboratory experiments.

PubMed

McNulty, P J; Pease, V P; Bond, V P

1977-01-01

Astronauts on Apollo and Skylab missions have reported observing a variety of visual phenomena when their eyes were closed and adapted to darkness. These observations were studied under controlled conditions during a number of sessions on board Apollo and Skylab spacecraft and the data available to date on these so-called light flashes are in the form of descriptions of the phenomena and frequency of occurrence. Similar visual phenomena have been demonstrated in a number of laboratories by exposing the eyes of human subjects to beams of neutrons, alpha particles, pions and protons. More than one physical mechanism is involved in the laboratory and space phenomena. No direct comparison of the laboratory and space observations has been made by observers who have experienced both. However, the range of visual phenomena observed in the laboratory is consistent with the Apollo and Skylab observations. Measured detection efficiencies can be used to estimate the frequencies with which various phenomena would be observed if that subject was exposed to cosmic rays in space.

Stokes phenomena in discrete Painlevé II.

PubMed

Joshi, N; Lustri, C J; Luu, S

2017-02-01

We consider the asymptotic behaviour of the second discrete Painlevé equation in the limit as the independent variable becomes large. Using asymptotic power series, we find solutions that are asymptotically pole-free within some region of the complex plane. These asymptotic solutions exhibit Stokes phenomena, which is typically invisible to classical power series methods. We subsequently apply exponential asymptotic techniques to investigate such phenomena, and obtain mathematical descriptions of the rapid switching behaviour associated with Stokes curves. Through this analysis, we determine the regions of the complex plane in which the asymptotic behaviour is described by a power series expression, and find that the behaviour of these asymptotic solutions shares a number of features with the tronquée and tri-tronquée solutions of the second continuous Painlevé equation.

Stokes phenomena in discrete Painlevé II

PubMed Central

Joshi, N.

2017-01-01

We consider the asymptotic behaviour of the second discrete Painlevé equation in the limit as the independent variable becomes large. Using asymptotic power series, we find solutions that are asymptotically pole-free within some region of the complex plane. These asymptotic solutions exhibit Stokes phenomena, which is typically invisible to classical power series methods. We subsequently apply exponential asymptotic techniques to investigate such phenomena, and obtain mathematical descriptions of the rapid switching behaviour associated with Stokes curves. Through this analysis, we determine the regions of the complex plane in which the asymptotic behaviour is described by a power series expression, and find that the behaviour of these asymptotic solutions shares a number of features with the tronquée and tri-tronquée solutions of the second continuous Painlevé equation. PMID:28293132

Mathematical Modeling of Diverse Phenomena

NASA Technical Reports Server (NTRS)

Howard, J. C.

1979-01-01

Tensor calculus is applied to the formulation of mathematical models of diverse phenomena. Aeronautics, fluid dynamics, and cosmology are among the areas of application. The feasibility of combining tensor methods and computer capability to formulate problems is demonstrated. The techniques described are an attempt to simplify the formulation of mathematical models by reducing the modeling process to a series of routine operations, which can be performed either manually or by computer.

Novel collective phenomena in high-energy proton–proton and proton–nucleus collisions

DOE PAGES

Dusling, Kevin; Li, Wei; Schenke, Björn

2016-01-22

The observation of long-range rapidity correlations among particles in high-multiplicity p–p and p–Pb collisions created new opportunities for investigating novel high-density QCD phenomena in small colliding systems. We also review experimental results related to the study of collective phenomena in small systems at RHIC and the LHC along with the related developments in theory and phenomenology. Finally, perspectives on possible future directions for research are discussed with the aim of exploring emergent QCD phenomena.

Some Phenomena on Negative Inversion Constructions

ERIC Educational Resources Information Center

Sung, Tae-Soo

2013-01-01

We examine the characteristics of NDI (negative degree inversion) and its relation with other inversion phenomena such as SVI (subject-verb inversion) and SAI (subject-auxiliary inversion). The negative element in the NDI construction may be" not," a negative adverbial, or a negative verb. In this respect, NDI has similar licensing…

Organic Bistable Memory Switching Phenomena in Squarylium-Dye Langmuir-Blodgett Films

NASA Astrophysics Data System (ADS)

Kushida, Masahito; Inomata, Hisao; Miyata, Hiroshi; Harada, Kieko; Saito, Kyoichi; Sugita, Kazuyuki

2003-06-01

We have investigated the relationship between the switching phenomena and H-like aggregates in squarylium-dye Langmuir-Blodgett (SQ LB) films. The current-voltage characteristics of SQ LB films sandwiched between the top gold electrode and the bottom aluminum electrode indicated conductance switching phenomena below the temperature of 100°C but not at 140°C. Current densities suddenly increased at switching voltages between 2 and 4 V. The switching voltage increased as the temperature increased between room temperature and 100°C. Current densities were 50-100 μA/cm2 in a low-impedance state (ON state). A high-impedance state (OFF state) can be recovered by applying a reverse bias, and therefore, these bistable devices are ideal for memory applications. The dependence of conductance switching phenomena and ultraviolet-visible absorption spectra on annealing temperatures was studied. The results revealed that conductance switching phenomena were caused by the presence of H-like aggregates in the SQ LB films.

Transformation and birth processes of the transient luminous phenomena's in the low atmosphere of the Hessdalen valley, Norway.

NASA Astrophysics Data System (ADS)

Gitle Hauge, Bjørn; Strand, Erling

2013-04-01

Transient louminous phenomenas has been observed in and over the Hessdalen valley for over 100 years. These phenomena's has been nicknamed "Hessdalen phenomenas", HP, and has been under permanent scientific investigation since 1998, when Norwegian, Italian and later French researchers installed different types of monitoring equipment in the valley. The earth's magnetic field, electromagnetic radiation in different bands, radioactive radiation, electrical resistance in the ground, ultrasound, and seismic activity are some of the signals/parameters that has been monitored. The valley has also been surveillanced by radar, optical spectrometers and automatic video recording devices. So far no electromagnetic radiation, except in the optical band, has been detected that can be coupled to the HP. The phenomenon is characterized by its horizontal movement, intense optical radiation when a transformation process occurs, different colours where white/yellow dominates, no sound, high speed, unpredictable flight patterns, seen by radar while optical invisible and often observed with continuous optical spectrum. The phenomena have been seen touching ground, without leaving burning marks and flying in higher altitudes over the valley apparently ignoring wind/weather conditions. The Hessdalen valley is located in the middle of Norway and is famous for its mines with iron, zinc and copper ore. Big deposits of ore still reside inside the valley, and the mountains are penetrated by several mineshafts, some has depth down to 1000m. No exact birthplace has been located and the phenomenon seems to emerge "out of thin air" anywhere in the valley. Any activity coupled to mineshafts has not been observed. In September 2006 a birth and transformation process was observed and several optical spectrums was obtained. The phenomena appear as a big white light possibly not more than some hundred meters above the ground in a desolated area. The phenomenon starts a transformation process

The effect of standing acoustic waves on the formation of laser-induced air plasmas.

PubMed

Craig, Stephanie M; Brownell, Kara; O'Leary, Brendon; Malfitano, Christopher; Kelley, Jude A

2013-03-01

The expected location of an air plasma produced by a focused YAG laser pulse has been found to be influenced by the acoustics of the surrounding environment. In open air, the expected location of a laser-induced air plasma is centered close to the focal point of the lens focusing the laser beam. When confining the same beam coaxially along the interior of a quartz tube, the expected location of the air plasma shifts away from the focal point, toward the focusing lens, in a region of less laser fluence. This shift is caused by an interaction between standing acoustic waves (formed from sound waves produced by previous laser-induced plasmas) and the impinging laser pulse. Standing acoustic waves in a tube produce areas (antinodes) of slightly higher and slightly lower pressure than ambient atmospheric conditions, that in turn have a noticeable affect on the probability of creating an air plasma at a given location. This leads to two observed phenomena: Increased probability of air plasma formation before the optical focal point is reached, and the formation of distinct (separate) air plasmas at the antinodes themselves.

Light Phenomena from the Nothing

NASA Astrophysics Data System (ADS)

Teodorani, M.

2004-11-01

The most recent results of scientific investigations on anomalous light phenomena, which were carried out in Hessdalen, Norway, are described and discussed. The data acquired so far show that the phenomenon is a plasma form triggered by piezoelectricity and maintained by electrochemical effects that become effective when a plasma concentration interacts with an atmosphere rich of water vapor and aerosols. It is also shown that the electrochemical mechanism able to permit an efficient confinement of the plasma can explain some peculiar kinematic and structural characteristics too, being the light phenomenon formed by clusters of small light balls, which are occasionally ejected from the core. The mechanism, with which amplitude time-variations of pulsating light phenomena occur, is also described. It is finally shown how, however, some peculiar aspects of the phenomenon, in particular the occurrence of some transiently geometric shapes, cannot be explained using a geophysical standard model. One hypothesis concerning quantum fluctuations of the zero point energy, including a possible interaction with a form of "electromagnetic intelligence", is discussed as a possible speculation, which is ventured in order to suggest to all physical scientists working in this field to carry out a more in-depth study of the light phenomenon in its entirety.

Review of Natural Phenomena Hazard (NPH) Assessments for the DOE Hanford Site

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

Snow, Robert L.; Ross, Steven B.

2011-09-15

The purpose of this review is to assess the need for updating Natural Phenomena Hazard (NPH) assessments for the DOE's Hanford Site, as required by DOE Order 420.1B Chapter IV, Natural Phenomena Hazards Mitigation, based on significant changes in state-of-the-art NPH assessment methodology or site-specific information. This review is an update and expansion to the September 2010 review of PNNL-19751, Review of Natural Phenomena Hazard (NPH) Assessments for the Hanford 200 Areas (Non-Seismic).

Microgravity Transport Phenomena Experiment (MTPE) Overview

NASA Technical Reports Server (NTRS)

Mason, Larry W.

1999-01-01

The Microgravity Transport Phenomena Experiment (MTPE) is a fluids experiment supported by the Fundamentals in Biotechnology program in association with the Human Exploration and Development of Space (BEDS) initiative. The MTP Experiment will investigate fluid transport phenomena both in ground based experiments and in the microgravity environment. Many fluid transport processes are affected by gravity. Osmotic flux kinetics in planar membrane systems have been shown to be influenced by gravimetric orientation, either through convective mixing caused by unstably stratified fluid layers, or through a stable fluid boundary layer structure that forms in association with the membrane. Coupled transport phenomena also show gravity related effects. Coefficients associated with coupled transport processes are defined in terms of a steady state condition. Buoyancy (gravity) driven convection interferes with the attainment of steady state, and the measurement of coupled processes. The MTP Experiment measures the kinetics of molecular migration that occurs in fluids, in response to the application of various driving potentials. Three separate driving potentials may be applied to the MTP Experiment fluids, either singly or in combination. The driving potentials include chemical potential, thermal potential, and electrical potential. Two separate fluid arrangements are used to study membrane mediated and bulk fluid transport phenomena. Transport processes of interest in membrane mediated systems include diffusion, osmosis, and streaming potential. Bulk fluid processes of interest include coupled phenomena such as the Soret Effect, Dufour Effect, Donnan Effect, and thermal diffusion potential. MTP Experiments are performed in the Microgravity Transport Apparatus (MTA), an instrument that has been developed specifically for precision measurement of transport processes. Experiment fluids are contained within the MTA fluid cells, designed to create a one dimensional flow geometry

[Dissociative phenomena in a sample of outpatients].

PubMed

Cantone, Daniela; Sperandeo, Raffaele; Maldonato, Mauro Nelson; Cozzolino, Pasquale; Perris, Francesco

2012-01-01

The study describes the frequency and the quality of dissociative phenomena and their relationship with axis I disorders and the psychopathological severity in outpatients. The sample (N=383) was subjected to MINI diagnostic interview and self-assessment scales DES and SCL-90. The data were analysed using SPSS. The 11,0% of subjects has a score ≥20 on DES. The 5,2% has no dissociative symptoms. The absorption images is the most frequent dissociative phenomenon, the less common is the dissociation amnesia. A relationship between dissociative phenomena and conditions unemployment, marital separation and single parties and an inverse relationship with age founded. Dissociative phenomena are more frequent in participants who have been diagnosed at least one axis I disorder and their severity is positively correlated with the number of diagnosed diseases and scores to the General Symptomatic Index. Our results point towards the existence of three types of dissociative experiences. The first type, represented by the factor absorption/imaginative involvement, is expressed along a continuum from normal to pathological; a second type, represented by the factor depersonalization/derealization, occurs in a significantly more intense and specific among subjects with axis I disorders; the latest manifestation dissociative, described by the dissociation amnesia, seems to have a predominantly typological feature that qualifies it as an experience not commonly distributed in the general population. The identifying of dissociative symptoms is necessary for the psychopathologic evaluation and to improve the effectiveness of treatment programs.

Transport Phenomena During Equiaxed Solidification of Alloys

NASA Technical Reports Server (NTRS)

Beckermann, C.; deGroh, H. C., III

1997-01-01

Recent progress in modeling of transport phenomena during dendritic alloy solidification is reviewed. Starting from the basic theorems of volume averaging, a general multiphase modeling framework is outlined. This framework allows for the incorporation of a variety of microscale phenomena in the macroscopic transport equations. For the case of diffusion dominated solidification, a simplified set of model equations is examined in detail and validated through comparisons with numerous experimental data for both columnar and equiaxed dendritic growth. This provides a critical assessment of the various model assumptions. Models that include melt flow and solid phase transport are also discussed, although their validation is still at an early stage. Several numerical results are presented that illustrate some of the profound effects of convective transport on the final compositional and structural characteristics of a solidified part. Important issues that deserve continuing attention are identified.

Time-Frequency and Non-Laplacian Phenomena at Radio Frequencies

DTIC Science & Technology

2017-01-22

Unlimited UU UU UU UU 22-01-2017 30-Sep-2012 30-Sep-2016 Final Report: Time -Frequency and Non-Laplacian Phenomena at Radio Frequencies The views...average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data... Time ‐Frequency and Non‐Laplacian Phenomena at Radio Frequencies  U.S. Army Research Office grant W911NF‐12‐1‐0526  Michael B. Steer  Department of

Nocturnal Air Seiches in the Arizona Meteor Crater

NASA Astrophysics Data System (ADS)

Muschinski, A.; Fritts, D. C.; Zhong, S.; Oncley, S. P.

2011-12-01

The Arizona Meteor Crater near Winslow, AZ is 170 m deep, has a diameter of 1.2 km, and it has a nearly circular shape. The motivation of the Meteor Crater Experiment (METCRAX), conducted in October 2006, was to use the Meteor Crater as a natural laboratory to study atmospheric phenomena that are typical for small basins. Among other observations, high-resolution wind, temperature and pressure measurements were collected with sonics and microbarometers, respectively, during the entire month. The sensors were mounted between 0.5 m and 8.5 m AGL on seven portable towers, five of which were located within the crater and two on the crater rim. Here we report observations of nocturnal air seiches, that is, standing gravity waves associated with the time-harmonic sloshing of the cold-air pool that forms at the bottom of the crater due to radiative cooling at night. We present time series, spectra, and spectrograms of temperature, wind and pressure fluctuations that characterize those air seiches. Typical seiche periods were 15 min. We compare the observations with the time-harmonic solutions of the shallow-water equation and with numerical simulations.

Understanding the reaction of nuclear graphite with molecular oxygen: Kinetics, transport, and structural evolution

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

Kane, Joshua J.; Contescu, Cristian I.; Smith, Rebecca E.

A thorough understanding of oxidation is important when considering the health and integrity of graphite components in graphite reactors. For the next generation of graphite reactors, HTGRs specifically, an unlikely air ingress has been deemed significant enough to have made its way into the licensing applications of many international licensing bodies. While a substantial body of literature exists on nuclear graphite oxidation in the presence of molecular oxygen and significant efforts have been made to characterize oxidation kinetics of various grades, the value of existing information is somewhat limited. Often, multiple competing processes, including reaction kinetics, mass transfer, and microstructuralmore » evolution, are lumped together into a single rate expression that limits the ability to translate this information to different conditions. This article reviews the reaction of graphite with molecular oxygen in terms of the reaction kinetics, gas transport, and microstructural evolution of graphite. It also presents the foundations of a model for the graphite-molecular oxygen reaction system that is kinetically independent of graphite grade, and is capable of describing both the bulk and local oxidation rates under a wide range of conditions applicable to air-ingress.« less

Understanding the reaction of nuclear graphite with molecular oxygen: Kinetics, transport, and structural evolution

DOE PAGES

Kane, Joshua J.; Contescu, Cristian I.; Smith, Rebecca E.; ...

2017-06-08

A thorough understanding of oxidation is important when considering the health and integrity of graphite components in graphite reactors. For the next generation of graphite reactors, HTGRs specifically, an unlikely air ingress has been deemed significant enough to have made its way into the licensing applications of many international licensing bodies. While a substantial body of literature exists on nuclear graphite oxidation in the presence of molecular oxygen and significant efforts have been made to characterize oxidation kinetics of various grades, the value of existing information is somewhat limited. Often, multiple competing processes, including reaction kinetics, mass transfer, and microstructuralmore » evolution, are lumped together into a single rate expression that limits the ability to translate this information to different conditions. This article reviews the reaction of graphite with molecular oxygen in terms of the reaction kinetics, gas transport, and microstructural evolution of graphite. It also presents the foundations of a model for the graphite-molecular oxygen reaction system that is kinetically independent of graphite grade, and is capable of describing both the bulk and local oxidation rates under a wide range of conditions applicable to air-ingress.« less

Maxwell Prize Talk: Scaling Laws for the Dynamical Plasma Phenomena

NASA Astrophysics Data System (ADS)

Ryutov, Livermore, Ca 94550, Usa, D. D.

2017-10-01

The scaling and similarity technique is a powerful tool for developing and testing reduced models of complex phenomena, including plasma phenomena. The technique has been successfully used in identifying appropriate simplified models of transport in quasistationary plasmas. In this talk, the similarity and scaling arguments will be applied to highly dynamical systems, in which temporal evolution of the plasma leads to a significant change of plasma dimensions, shapes, densities, and other parameters with respect to initial state. The scaling and similarity techniques for dynamical plasma systems will be presented as a set of case studies of problems from various domains of the plasma physics, beginning with collisonless plasmas, through intermediate collisionalities, to highly collisional plasmas describable by the single-fluid MHD. Basic concepts of the similarity theory will be introduced along the way. Among the results discussed are: self-similarity of Langmuir turbulence driven by a hot electron cloud expanding into a cold background plasma; generation of particle beams in disrupting pinches; interference between collisionless and collisional phenomena in the shock physics; similarity for liner-imploded plasmas; MHD similarities with an emphasis on the effect of small-scale (turbulent) structures on global dynamics. Relations between astrophysical phenomena and scaled laboratory experiments will be discussed.

Hydraulic pressures generated in magnetic ionic liquids by paramagnetic fluid/air interfaces inside of uniform tangential magnetic fields.

PubMed

Scovazzo, Paul; Portugal, Carla A M; Rosatella, Andreia A; Afonso, Carlos A M; Crespo, João G

2014-08-15

Magnetic Ionic Liquid (MILs), novel magnetic molecules that form "pure magnetic liquids," will follow the Ferrohydrodynamic Bernoulli Relationship. Based on recent literature, the modeling of this fluid system is an open issue and potentially controversial. We imposed uniform magnetic fields parallel to MIL/air interfaces where the capillary forces were negligible, the Quincke Problem. The size and location of the bulk fluid as well as the size and location of the fluid/air interface inside of the magnetic field were varied. MIL properties varied included the density, magnetic susceptibility, chemical structure, and magnetic element. Uniform tangential magnetic fields pulled the MILs up counter to gravity. The forces per area were not a function of the volume, the surface area inside of the magnetic field, or the volume displacement. However, the presence of fluid/air interfaces was necessary for the phenomena. The Ferrohydrodynamic Bernoulli Relationship predicted the phenomena with the forces being directly related to the fluid's volumetric magnetic susceptibility and the square of the magnetic field strength. [emim][FeCl4] generated the greatest hydraulic head (64-mm or 910 Pa at 1.627 Tesla). This work could aid in experimental design, when free surfaces are involved, and in the development of MIL applications. Copyright © 2014 Elsevier Inc. All rights reserved.

Aerothermodynamic flow phenomena of the airframe-integrated supersonic combustion ramjet

NASA Technical Reports Server (NTRS)

Walton, James T.

1992-01-01

The unique component flow phenomena is discussed of the airframe-integrated supersonic combustion ramjet (scramjet) in a format geared towards new players in the arena of hypersonic propulsion. After giving an overview of the scramjet aerothermodynamic cycle, the characteristics are then covered individually of the vehicle forebody, inlet, combustor, and vehicle afterbody/nozzle. Attention is given to phenomena such as inlet speeding, inlet starting, inlet spillage, fuel injection, thermal choking, and combustor-inlet interaction.

Moon-based Earth Observation for Large Scale Geoscience Phenomena

NASA Astrophysics Data System (ADS)

Guo, Huadong; Liu, Guang; Ding, Yixing

2016-07-01

The capability of Earth observation for large-global-scale natural phenomena needs to be improved and new observing platform are expected. We have studied the concept of Moon as an Earth observation in these years. Comparing with manmade satellite platform, Moon-based Earth observation can obtain multi-spherical, full-band, active and passive information,which is of following advantages: large observation range, variable view angle, long-term continuous observation, extra-long life cycle, with the characteristics of longevity ,consistency, integrity, stability and uniqueness. Moon-based Earth observation is suitable for monitoring the large scale geoscience phenomena including large scale atmosphere change, large scale ocean change,large scale land surface dynamic change,solid earth dynamic change,etc. For the purpose of establishing a Moon-based Earth observation platform, we already have a plan to study the five aspects as follows: mechanism and models of moon-based observing earth sciences macroscopic phenomena; sensors' parameters optimization and methods of moon-based Earth observation; site selection and environment of moon-based Earth observation; Moon-based Earth observation platform; and Moon-based Earth observation fundamental scientific framework.

Daily Cycle of Air Temperature and Surface Temperature in Stone Forest

NASA Astrophysics Data System (ADS)

Wang, K.; Li, Y.; Wang, X.; Yuan, M.

2013-12-01

Urbanization is one of the most profound human activities that impact on climate change. In cities, where are highly artificial areas, the conflict between human activity and natural climate is particularly prominent. Urban areas always have the larger area of impervious land, the higher consumption of greenhouse gases, more emissions of anthropogenic heat and air pollution, all contribute to the urban warming phenomena. Understanding the mechanisms causing a variety of phenomena involved in the urban warming is critical to distinguish the anthropogenic effect and natural variation in the climate change. However, the exact dynamics of urban warming were poorly understood, and effective control strategies are not available. Here we present a study of the daily cycle of air temperature and surface temperature in Stone Forest. The specific heat of the stones in the Stone Forest and concrete of the man-made structures within the cities are approximate. Besides, the height of the Stone Forest and the height of buildings within the city are also similar. As a scenic area, the Stone Forest is being preserved and only opened for sightseeing. There is no anthropogenic heat, as well air pollution within the Stone Forest. The thermal environment in Stone Forest can be considered to be a simulation of thermal environment in the city, which can reveal the effect of man-made structures on urban thermal environment. We conducted the field studies and numerical analysis in the Stone Forest for 4 typical urban morphology and environment scenarios, including high-rise compact cities, low-rise sparse cities, garden cities and isolated single stone. Air temperature and relative humidity were measured every half an hour in 15 different locations, which within different spatial distribution of stones and can represent the four urban scenarios respectively. At the same time, an infrared camera was used to take thermal images and get the hourly surface temperatures of stones and

Multipoint observations of plasma phenomena made in space by Cluster

NASA Astrophysics Data System (ADS)

Goldstein, M. L.; Escoubet, P.; Hwang, K.-Joo; Wendel, D. E.; Viñas, A.-F.; Fung, S. F.; Perri, S.; Servidio, S.; Pickett, J. S.; Parks, G. K.; Sahraoui, F.; Gurgiolo, C.; Matthaeus, W.; Weygand, J. M.

2015-06-01

Plasmas are ubiquitous in nature, surround our local geospace environment, and permeate the universe. Plasma phenomena in space give rise to energetic particles, the aurora, solar flares and coronal mass ejections, as well as many energetic phenomena in interstellar space. Although plasmas can be studied in laboratory settings, it is often difficult, if not impossible, to replicate the conditions (density, temperature, magnetic and electric fields, etc.) of space. Single-point space missions too numerous to list have described many properties of near-Earth and heliospheric plasmas as measured both in situ and remotely (see http://www.nasa.gov/missions/#.U1mcVmeweRY for a list of NASA-related missions). However, a full description of our plasma environment requires three-dimensional spatial measurements. Cluster is the first, and until data begin flowing from the Magnetospheric Multiscale Mission (MMS), the only mission designed to describe the three-dimensional spatial structure of plasma phenomena in geospace. In this paper, we concentrate on some of the many plasma phenomena that have been studied using data from Cluster. To date, there have been more than 2000 refereed papers published using Cluster data but in this paper we will, of necessity, refer to only a small fraction of the published work. We have focused on a few basic plasma phenomena, but, for example, have not dealt with most of the vast body of work describing dynamical phenomena in Earth's magnetosphere, including the dynamics of current sheets in Earth's magnetotail and the morphology of the dayside high latitude cusp. Several review articles and special publications are available that describe aspects of that research in detail and interested readers are referred to them (see for example, Escoubet et al. 2005 Multiscale Coupling of Sun-Earth Processes, p. 459, Keith et al. 2005 Sur. Geophys. 26, 307-339, Paschmann et al. 2005 Outer Magnetospheric Boundaries: Cluster Results, Space Sciences Series

Quasi-perpetual discharge behaviour in p-type Ge-air batteries.

PubMed

Ocon, Joey D; Kim, Jin Won; Abrenica, Graniel Harne A; Lee, Jae Kwang; Lee, Jaeyoung

2014-11-07

Metal-air batteries continue to become attractive energy storage and conversion systems due to their high energy and power densities, safer chemistries, and economic viability. Semiconductor-air batteries - a term we first define here as metal-air batteries that use semiconductor anodes such as silicon (Si) and germanium (Ge) - have been introduced in recent years as new high-energy battery chemistries. In this paper, we describe the excellent doping-dependent discharge kinetics of p-type Ge anodes in a semiconductor-air cell employing a gelled KOH electrolyte. Owing to its Fermi level, n-type Ge is expected to have lower redox potential and better electronic conductivity, which could potentially lead to a higher operating voltage and better discharge kinetics. Nonetheless, discharge measurements demonstrated that this prediction is only valid at the low current regime and breaks down at the high current density region. The p-type Ge behaves extremely better at elevated currents, evident from the higher voltage, more power available, and larger practical energy density from a very long discharge time, possibly arising from the high overpotential for surface passivation. A primary semiconductor-air battery, powered by a flat p-type Ge as a multi-electron anode, exhibited an unprecedented full discharge capacity of 1302.5 mA h gGe(-1) (88% anode utilization efficiency), the highest among semiconductor-air cells, notably better than new metal-air cells with three-dimensional and nanostructured anodes, and at least two folds higher than commercial Zn-air and Al-air cells. We therefore suggest that this study be extended to doped-Si anodes, in order to pave the way for a deeper understanding on the discharge phenomena in alkaline metal-air conversion cells with semiconductor anodes for specific niche applications in the future.

Multi-pollutant surface objective analyses and mapping of air quality health index over North America.

PubMed

Robichaud, Alain; Ménard, Richard; Zaïtseva, Yulia; Anselmo, David

2016-01-01

Air quality, like weather, can affect everyone, but responses differ depending on the sensitivity and health condition of a given individual. To help protect exposed populations, many countries have put in place real-time air quality nowcasting and forecasting capabilities. We present in this paper an optimal combination of air quality measurements and model outputs and show that it leads to significant improvements in the spatial representativeness of air quality. The product is referred to as multi-pollutant surface objective analyses (MPSOAs). Moreover, based on MPSOA, a geographical mapping of the Canadian Air Quality Health Index (AQHI) is also presented which provides users (policy makers, public, air quality forecasters, and epidemiologists) with a more accurate picture of the health risk anytime and anywhere in Canada and the USA. Since pollutants can also behave as passive atmospheric tracers, they provide information about transport and dispersion and, hence, reveal synoptic and regional meteorological phenomena. MPSOA could also be used to build air pollution climatology, compute local and national trends in air quality, and detect systematic biases in numerical air quality (AQ) models. Finally, initializing AQ models at regular time intervals with MPSOA can produce more accurate air quality forecasts. It is for these reasons that the Canadian Meteorological Centre (CMC) in collaboration with the Air Quality Research Division (AQRD) of Environment Canada has recently implemented MPSOA in their daily operations.

ARL Support of NRL Rocket Experiments to Investigate Ionospheric Phenomena

DTIC Science & Technology

2010-08-31

reallocate the funds to support NRL’s ongoing efforts to develop an ionospheric tomography network in South America to support the C/NOFS satellite...of NRL Rocket Experiments to Investigate Ionospheric Phenomena 5a. CONTRACT NUMBER N00173-09-1-G036 5b. GRANT NUMBER N00173-09-1-G036 5c...1-G036 ARL Support of NRL Rocket Experiments to Investigate Ionospheric Phenomena BY DR. TREVOR W. GARNER APPLIED RESEARCH LABORATORIES THE

Displaying Computer Simulations Of Physical Phenomena

NASA Technical Reports Server (NTRS)

Watson, Val

1991-01-01

Paper discusses computer simulation as means of experiencing and learning to understand physical phenomena. Covers both present simulation capabilities and major advances expected in near future. Visual, aural, tactile, and kinesthetic effects used to teach such physical sciences as dynamics of fluids. Recommends classrooms in universities, government, and industry be linked to advanced computing centers so computer simulations integrated into education process.

Natural phenomena exhibited by forest fires

Treesearch

J. S. Barrows

1961-01-01

Forest fire phenomena are presented through a series of motion pictures and 35 mm slides. These films have been taken by the staffs of the Southeastern, Pacific Southwest, and Intermountain Forest and Range Experiment Stations of the U. S. Forest Service and by Dr. Vincent J. Schaefer during the course of fire research activities. Both regular speed and time-lapse...

AIRS Detection of Dust: Global Map for July 2003

NASA Technical Reports Server (NTRS)

2007-01-01

The averaged brightness temperature differences between the 961 and 1231 cm-1 AIRS channels for July 2003, reveal long range transport of Sahara Dust across the Atlantic.

The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

Joint space-time geostatistical model for air quality surveillance

NASA Astrophysics Data System (ADS)

Russo, A.; Soares, A.; Pereira, M. J.

2009-04-01

Air pollution and peoples' generalized concern about air quality are, nowadays, considered to be a global problem. Although the introduction of rigid air pollution regulations has reduced pollution from industry and power stations, the growing number of cars on the road poses a new pollution problem. Considering the characteristics of the atmospheric circulation and also the residence times of certain pollutants in the atmosphere, a generalized and growing interest on air quality issues led to research intensification and publication of several articles with quite different levels of scientific depth. As most natural phenomena, air quality can be seen as a space-time process, where space-time relationships have usually quite different characteristics and levels of uncertainty. As a result, the simultaneous integration of space and time is not an easy task to perform. This problem is overcome by a variety of methodologies. The use of stochastic models and neural networks to characterize space-time dispersion of air quality is becoming a common practice. The main objective of this work is to produce an air quality model which allows forecasting critical concentration episodes of a certain pollutant by means of a hybrid approach, based on the combined use of neural network models and stochastic simulations. A stochastic simulation of the spatial component with a space-time trend model is proposed to characterize critical situations, taking into account data from the past and a space-time trend from the recent past. To identify near future critical episodes, predicted values from neural networks are used at each monitoring station. In this paper, we describe the design of a hybrid forecasting tool for ambient NO2 concentrations in Lisbon, Portugal.

Average Tropical Relative Humidity from AIRS, Dec-Feb 2002-2005

NASA Technical Reports Server (NTRS)

2007-01-01

The average tropospheric relative humidity from AIRS for the four December-February periods during 2002 through 2005.

The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

Using Temperature-Dependent Phenomena at Oxide Surfaces for Species Recognition in Chemical Sensing.

NASA Astrophysics Data System (ADS)

Semancik, Steve; Meier, Douglas; Evju, Jon; Benkstein, Kurt; Boger, Zvi; Montgomery, Chip

2006-03-01

Nanostructured films of SnO2 and TiO2 have been deposited on elements in MEMS arrays to fabricate solid state conductometric gas microsensors. The multilevel platforms within an array, called microhotplates, are individually addressable for localized temperature control and measurement of sensing film electrical conductance. Temperature variations of the microhotplates are employed in thermally-activated CVD oxide film growth, and for rapid temperature-programmed operation of the microsensors. Analytical information on environmental gas phase composition is produced temporally as purposeful thermal fluctuations provide energetic and kinetic control of surface reaction and adsorption/desorption phenomena. Resulting modulations of oxide adsorbate populations cause changing charge transfer behavior and measurable conductance responses. Rich data streams from different sensing films in the arrays have been analyzed by Artificial Neural Networks (ANN) to successfully recognize low concentration species in mixed gases. We illustrate capabilities of the approach and technology in the homeland security area, where dangerous chemicals (TICs, CWSs and CWAs) have been detected at 10-100 ppb levels in interference-spiked air backgrounds.

Collective Phenomena In Volume And Surface Barrier Discharges

NASA Astrophysics Data System (ADS)

Kogelschatz, U.

2010-07-01

Barrier discharges are increasingly used as a cost-effective means to produce non-equilibrium plasmas at atmospheric pressure. This way, copious amounts of electrons, ions, free radicals and excited species can be generated without appreciable gas heating. In most applications the barrier is made of dielectric material. In laboratory experiments also the use of resistive, ferroelectric and semiconducting materials has been investigated, also porous ceramic layers and dielectric barriers with controlled surface conductivity. Major applications utilizing mainly dielectric barriers include ozone generation, surface cleaning and modification, polymer and textile treatment, sterilization, pollution control, CO2 lasers, excimer lamps, plasma display panels (flat TV screens). More recent research efforts are also devoted to biomedical applications and to plasma actuators for flow control. Sinu- soidal feeding voltages at various frequencies as well as pulsed excitation schemes are used. Volume as well as surface barrier discharges can exist in the form of filamentary, regularly patterned or laterally homogeneous discharges. Reviews of the subject and the older literature on barrier discharges were published by Kogelschatz (2002, 2003), by Wagner et al. (2003) and by Fridman et al. (2005). A detailed discussion of various properties of barrier discharges can also be found in the recent book "Non-Equilibrium Air Plasmas at Atmospheric Pressure" by Becker et al. (2005). The physical effects leading to collective phenomena in volume and surface barrier discharges will be discussed in detail. Special attention will be given to self-organization of current filaments. Main similarities and differences of the two types of barrier discharges will be elaborated.

Emergent Phenomena at Oxide Interfaces

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

Hwang, H.Y.

2012-02-16

Transition metal oxides (TMOs) are an ideal arena for the study of electronic correlations because the s-electrons of the transition metal ions are removed and transferred to oxygen ions, and hence the strongly correlated d-electrons determine their physical properties such as electrical transport, magnetism, optical response, thermal conductivity, and superconductivity. These electron correlations prohibit the double occupancy of metal sites and induce a local entanglement of charge, spin, and orbital degrees of freedom. This gives rise to a variety of phenomena, e.g., Mott insulators, various charge/spin/orbital orderings, metal-insulator transitions, multiferroics, and superconductivity. In recent years, there has been a burstmore » of activity to manipulate these phenomena, as well as create new ones, using oxide heterostructures. Most fundamental to understanding the physical properties of TMOs is the concept of symmetry of the order parameter. As Landau recognized, the essence of phase transitions is the change of the symmetry. For example, ferromagnetic ordering breaks the rotational symmetry in spin space, i.e., the ordered phase has lower symmetry than the Hamiltonian of the system. There are three most important symmetries to be considered here. (i) Spatial inversion (I), defined as r {yields} -r. In the case of an insulator, breaking this symmetry can lead to spontaneous electric polarization, i.e. ferroelectricity, or pyroelectricity once the point group belongs to polar group symmetry. (ii) Time-reversal symmetry (T) defined as t {yields} -t. In quantum mechanics, the time-evolution of the wave-function {Psi} is given by the phase factor e{sup -iEt/{h_bar}} with E being the energy, and hence time-reversal basically corresponds to taking the complex conjugate of the wave-function. Also the spin, which is induced by the 'spinning' of the particle, is reversed by time-reversal. Broken T-symmetry is most naturally associated with magnetism, since the

Mathematical methods of studying physical phenomena

NASA Astrophysics Data System (ADS)

Man'ko, Margarita A.

2013-03-01

In recent decades, substantial theoretical and experimental progress was achieved in understanding the quantum nature of physical phenomena that serves as the foundation of present and future quantum technologies. Quantum correlations like the entanglement of the states of composite systems, the phenomenon of quantum discord, which captures other aspects of quantum correlations, quantum contextuality and, connected with these phenomena, uncertainty relations for conjugate variables and entropies, like Shannon and Rényi entropies, and the inequalities for spin states, like Bell inequalities, reflect the recently understood quantum properties of micro and macro systems. The mathematical methods needed to describe all quantum phenomena mentioned above were also the subject of intense studies in the end of the last, and beginning of the new, century. In this section of CAMOP 'Mathematical Methods of Studying Physical Phenomena' new results and new trends in the rapidly developing domain of quantum (and classical) physics are presented. Among the particular topics under discussion there are some reviews on the problems of dynamical invariants and their relations with symmetries of the physical systems. In fact, this is a very old problem of both classical and quantum systems, e.g. the systems of parametric oscillators with time-dependent parameters, like Ermakov systems, which have specific constants of motion depending linearly or quadratically on the oscillator positions and momenta. Such dynamical invariants play an important role in studying the dynamical Casimir effect, the essence of the effect being the creation of photons from the vacuum in a cavity with moving boundaries due to the presence of purely quantum fluctuations of the electromagnetic field in the vacuum. It is remarkable that this effect was recently observed experimentally. The other new direction in developing the mathematical approach in physics is quantum tomography that provides a new vision of

Laser-assisted surface modification of Ti-implant in air and water environment

NASA Astrophysics Data System (ADS)

Trtica, M.; Stasic, J.; Batani, D.; Benocci, R.; Narayanan, V.; Ciganovic, J.

2018-01-01

A study of the surface modification of titanium CP grade 2 implant/target with high intensity picosecond (Nd:YAG) laser, operating at 1064 nm wavelength and pulse duration of 40 ps, in gaseous (air) and liquid (water) medium, is presented. The exposure of Ti to a laser pulse energy of 17 mJ in both media - gaseous and liquid, induced specific surface features and phenomena: (i) enhancement of the implant surface roughness (higher in water). In this context, the damage depth is more prominent in water (as high as ∼40 μm) vs. air (∼14 μm). Also, the appearance of laser induced periodic surface structures (LIPSS) is recorded in both media, at periphery area, while in water they are registered at lower pulse count; (ii) variation of chemical surface content depending on the applied medium. Thus, in the central irradiation region, the oxygen was absent in air while its concentration was relatively high (6.44 wt%) in case of water; (iii) possibility of direct collection of synthesized titanium based nanoparticles in water environment, and (iv) formation of the plasma above the sample in both mediums, more volumetrically confined in water. These investigations showed that surface structuring and observed phenomena are in strong correlation with the medium used. The liquid - water seems like the medium of choice in regard to titanium implant biocompatibility and bio-activity (the water is a favorable medium for build-up of the oxide layer which affects bioactivity). The process of laser interaction with titanium implant targets was accompanied by the formation of plasma plume, which provides the additional sterilizing effect facilitating contaminant-free conditions.

Experimental studies of contact angle hysteresis phenomena on polymer surfaces – Toward the understanding and control of wettability for different applications.

PubMed

Grundke, K; Pöschel, K; Synytska, A; Frenzel, R; Drechsler, A; Nitschke, M; Cordeiro, A L; Uhlmann, P; Welzel, P B

2015-08-01

Contact angle hysteresis phenomena on polymer surfaces have been studied by contact angle measurements using sessile liquid droplets and captive air bubbles in conjunction with a drop shape method known as Axisymmetric Drop Shape Analysis - Profile (ADSA-P). In addition, commercially available sessile drop goniometer techniques were used. The polymer surfaces were characterized with respect to their surface structure (morphology, roughness, swelling) and surface chemistry (elemental surface composition, acid-base characteristics) by scanning electron microscopy (SEM), scanning force microscopy (SFM), ellipsometry, X-ray photoelectron spectroscopy (XPS) and streaming potential measurements. Heterogeneous polymer surfaces with controlled roughness and chemical composition were prepared by different routes using plasma etching and subsequent dip coating or grafting of polymer brushes, anodic oxidation of aluminium substrates coated with thin polymer films, deposition techniques to create regular patterned and rough fractal surfaces from core-shell particles, and block copolymers. To reveal the effects of swelling and reorientation at the solid/liquid interface contact angle hysteresis phenomena on polyimide surfaces, cellulose membranes, and thermo-responsive hydrogels have been studied. The effect of different solutes in the liquid (electrolytes, surfactants) and their impact on contact angle hysteresis were characterized for solid polymers without and with ionizable functional surface groups in aqueous electrolyte solutions of different ion concentrations and pH and for photoresist surfaces in cationic aqueous surfactant solutions. The work is an attempt toward the understanding of contact angle hysteresis phenomena on polymer surfaces aimed at the control of wettability for different applications. Copyright © 2014 Elsevier B.V. All rights reserved.

The dynamics of information-driven coordination phenomena: A transfer entropy analysis

PubMed Central

Borge-Holthoefer, Javier; Perra, Nicola; Gonçalves, Bruno; González-Bailón, Sandra; Arenas, Alex; Moreno, Yamir; Vespignani, Alessandro

2016-01-01

Data from social media provide unprecedented opportunities to investigate the processes that govern the dynamics of collective social phenomena. We consider an information theoretical approach to define and measure the temporal and structural signatures typical of collective social events as they arise and gain prominence. We use the symbolic transfer entropy analysis of microblogging time series to extract directed networks of influence among geolocalized subunits in social systems. This methodology captures the emergence of system-level dynamics close to the onset of socially relevant collective phenomena. The framework is validated against a detailed empirical analysis of five case studies. In particular, we identify a change in the characteristic time scale of the information transfer that flags the onset of information-driven collective phenomena. Furthermore, our approach identifies an order-disorder transition in the directed network of influence between social subunits. In the absence of clear exogenous driving, social collective phenomena can be represented as endogenously driven structural transitions of the information transfer network. This study provides results that can help define models and predictive algorithms for the analysis of societal events based on open source data. PMID:27051875

The dynamics of information-driven coordination phenomena: A transfer entropy analysis.

PubMed

Borge-Holthoefer, Javier; Perra, Nicola; Gonçalves, Bruno; González-Bailón, Sandra; Arenas, Alex; Moreno, Yamir; Vespignani, Alessandro

2016-04-01

Data from social media provide unprecedented opportunities to investigate the processes that govern the dynamics of collective social phenomena. We consider an information theoretical approach to define and measure the temporal and structural signatures typical of collective social events as they arise and gain prominence. We use the symbolic transfer entropy analysis of microblogging time series to extract directed networks of influence among geolocalized subunits in social systems. This methodology captures the emergence of system-level dynamics close to the onset of socially relevant collective phenomena. The framework is validated against a detailed empirical analysis of five case studies. In particular, we identify a change in the characteristic time scale of the information transfer that flags the onset of information-driven collective phenomena. Furthermore, our approach identifies an order-disorder transition in the directed network of influence between social subunits. In the absence of clear exogenous driving, social collective phenomena can be represented as endogenously driven structural transitions of the information transfer network. This study provides results that can help define models and predictive algorithms for the analysis of societal events based on open source data.

Brain functional integration: an epidemiologic study on stress-producing dissociative phenomena.

PubMed

Sperandeo, Raffaele; Monda, Vincenzo; Messina, Giovanni; Carotenuto, Marco; Maldonato, Nelson Mauro; Moretto, Enrico; Leone, Elena; De Luca, Vincenzo; Monda, Marcellino; Messina, Antonietta

2018-01-01

Dissociative phenomena are common among psychiatric patients; the presence of these symptoms can worsen the prognosis, increasing the severity of their clinical conditions and exposing them to increased risk of suicidal behavior. Personality disorders as long duration stressful experiences may support the development of dissociative phenomena. In 933 psychiatric outpatients consecutively recruited, presence of dissociative phenomena was identified with the Dissociative Experience Scale (DES). Dissociative phenomena were significantly more severe in the group of people with mental disorders and/or personality disorders. All psychopathologic traits detected with the symptom checklist-90-revised had a significant correlation with the total score on the DES. Using total DES score as the dependent variable, a linear regression model was constructed. Mental and personality disorders which were associated with greater severity of dissociative phenomena on analysis of variance were included as predictors; scores from the nine scales of symptom checklist-90-revised, significantly correlated to total DES score, were used as covariates. The model consisted of seven explanatory variables (four factors and three covariates) explaining 82% of variance. The four significant factors were the presence of borderline and narcissistic personality disorder, substance abuse disorders and psychotic disorders. Significant covariates were psychopathologic traits of anger, psychoticism and obsessiveness. This study, confirming Janet's theory, explains that, mental disorders and psychopathologic experiences of patients can configure the chronic stress condition that produces functional damage to the adaptive executive system. The symptoms of dissociative depersonalization/derealization and dissociative amnesia can be explained, in large part, through their current and previous psychopathologic experiences.

Brain functional integration: an epidemiologic study on stress-producing dissociative phenomena

PubMed Central

Messina, Giovanni; Carotenuto, Marco; Maldonato, Nelson Mauro; Moretto, Enrico; Leone, Elena; De Luca, Vincenzo; Monda, Marcellino; Messina, Antonietta

2018-01-01

Dissociative phenomena are common among psychiatric patients; the presence of these symptoms can worsen the prognosis, increasing the severity of their clinical conditions and exposing them to increased risk of suicidal behavior. Personality disorders as long duration stressful experiences may support the development of dissociative phenomena. In 933 psychiatric outpatients consecutively recruited, presence of dissociative phenomena was identified with the Dissociative Experience Scale (DES). Dissociative phenomena were significantly more severe in the group of people with mental disorders and/or personality disorders. All psychopathologic traits detected with the symptom checklist-90-revised had a significant correlation with the total score on the DES. Using total DES score as the dependent variable, a linear regression model was constructed. Mental and personality disorders which were associated with greater severity of dissociative phenomena on analysis of variance were included as predictors; scores from the nine scales of symptom checklist-90-revised, significantly correlated to total DES score, were used as covariates. The model consisted of seven explanatory variables (four factors and three covariates) explaining 82% of variance. The four significant factors were the presence of borderline and narcissistic personality disorder, substance abuse disorders and psychotic disorders. Significant covariates were psychopathologic traits of anger, psychoticism and obsessiveness. This study, confirming Janet’s theory, explains that, mental disorders and psychopathologic experiences of patients can configure the chronic stress condition that produces functional damage to the adaptive executive system. The symptoms of dissociative depersonalization/derealization and dissociative amnesia can be explained, in large part, through their current and previous psychopathologic experiences. PMID:29296086

I-NERI Quarterly Technical Report (April 1 to June 30, 2005)

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

Chang Oh; Prof. Hee Cheon NO; Prof. John Lee

2005-06-01

The objective of this Korean/United States/laboratory/university collaboration is to develop new advanced computational methods for safety analysis codes for very-high-temperature gas-cooled reactors (VHTGRs) and numerical and experimental validation of these computer codes. This study consists of five tasks for FY-03: (1) development of computational methods for the VHTGR, (2) theoretical modification of aforementioned computer codes for molecular diffusion (RELAP5/ATHENA) and modeling CO and CO2 equilibrium (MELCOR), (3) development of a state-of-the-art methodology for VHTGR neutronic analysis and calculation of accurate power distributions and decay heat deposition rates, (4) reactor cavity cooling system experiment, and (5) graphite oxidation experiment. Second quartermore » of Year 3: (A) Prof. NO and Kim continued Task 1. As a further plant application of GAMMA code, we conducted two analyses: IAEA GT-MHR benchmark calculation for LPCC and air ingress analysis for PMR 600MWt. The GAMMA code shows comparable peak fuel temperature trend to those of other country codes. The analysis results for air ingress show much different trend from that of previous PBR analysis: later onset of natural circulation and less significant rise in graphite temperature. (B) Prof. Park continued Task 2. We have designed new separate effect test device having same heat transfer area and different diameter and total number of U-bands of air cooling pipe. New design has smaller pressure drop in the air cooling pipe than the previous one as designed with larger diameter and less number of U-bands. With the device, additional experiments have been performed to obtain temperature distributions of the water tank, the surface and the center of cooling pipe on axis. The results will be used to optimize the design of SNU-RCCS. (C) Prof. NO continued Task 3. The experimental work of air ingress is going on without any concern: With nuclear graphite IG-110, various kinetic parameters and

Laboratory Measurements of Cometary Photochemical Phenomena.

DTIC Science & Technology

1981-12-04

PROGFIAM ELEMENT.PROJECT TASK Laser .Chemistry Division AREA & WORK UNIT NUMaZRS Department of Chemistry - Howard University NR.051-733 Wash’ ngtQn, D. C...William M. Jackson Laser Chemistry Division Department of Chemistry Howard University .Washington, D. C. 20059 / Published by Jet Propulsion Laboratory...MEASUREMENTS OF COMETARY PHOTOCHEMICAL PHENOMENA William M. Jackson Howard University Washington, DC 20059 Abstract Laboratory experiments are described

Phenomena and Diosignes of Aratous

NASA Astrophysics Data System (ADS)

Avgoloupis, S. I.

2013-01-01

Aratous (305-240B.C.) was a singular intellectual, writer and poet which engage himself to compose a very interesting astronomical poet, using the "Dactylous sixstage' style, the formal style of the ancient Greek Epic poetry. This astronomic poem of Aratous "Phenomena and Diosignes" became very favorite reading during the Alexandrine, the Romman and the Byzandin eras as well and had received many praises from significant poets and particularly from Hipparchous and from Theonas from Alexandria, an astronomer of 4rth century A.C.(in Greeks)

Quantum phenomena in gravitational field

NASA Astrophysics Data System (ADS)

Bourdel, Th.; Doser, M.; Ernest, A. D.; Voronin, A. Yu.; Voronin, V. V.

2011-10-01

The subjects presented here are very different. Their common feature is that they all involve quantum phenomena in a gravitational field: gravitational quantum states of ultracold antihydrogen above a material surface and measuring a gravitational interaction of antihydrogen in AEGIS, a quantum trampoline for ultracold atoms, and a hypothesis on naturally occurring gravitational quantum states, an Eötvös-type experiment with cold neutrons and others. Considering them together, however, we could learn that they have many common points both in physics and in methodology.

Release phenomena and iterative activities in psychiatric geriatric patients

PubMed Central

Villeneuve, A.; Turcotte, J.; Bouchard, M.; Côté, J. M.; Jus, A.

1974-01-01

This survey was undertaken to assess the frequency of some of the so-called release phenomena and iterative activities in an aged psychiatric population. Three groups of geriatric psychiatric patients with diagnoses of (I) organic brain syndrome, including senile dementia (56), (II) functional psychoses, predominantly schizophrenia (51) and (III) chronic schizophrenia never treated by neuroleptics or other biologic agents (16), were compared with (IV) a control group of 32 elderly people in good physical and mental health. In general, for the manifestations studied, the geriatric psychiatric patients suffering from an organic brain syndrome and treated with neuroleptics differed notably from the control group. This latter group, although older, had few neurological signs of senescence and the spontaneous oral movements usually associated with the use of neuroleptics were absent. Release phenomena such as the grasp and pouting reflexes, as well as the stereotyped activities, were encountered significantly more frequently in patients with an organic brain syndrome than in the two other groups of patients. Our survey has yielded limited results with regard to the possible influence of type of illness and neuroleptic treatment on the incidence of release phenomena and iterative activities. PMID:4810188

Contamination of piped medical gas supply with water.

PubMed

Hay, H

2000-08-01

The failure of anaesthetic equipment as a result of maintenance is extremely rare. The ingress of water into the flowmeters of an anaesthetic machine from the piped medical air supply is reported and is possibly unique. The piped medical air supply was open to the atmosphere during maintenance. Water condensed in the gas pipeline and this was not noticed during subsequent testing. Water was seen leaking from the orthopaedic air tools used for surgery but was assumed to be from the autoclaving process. Later the same day, when medical air from the piped source was used as part of the gas mixture for a general anaesthetic, water was seen filling the barrel of the flowmeter air control valve. This could have had far-reaching and dangerous consequences for the patient, which were fortunately averted.

Fast Particle Methods for Multiscale Phenomena Simulations

NASA Technical Reports Server (NTRS)

Koumoutsakos, P.; Wray, A.; Shariff, K.; Pohorille, Andrew

2000-01-01

We are developing particle methods oriented at improving computational modeling capabilities of multiscale physical phenomena in : (i) high Reynolds number unsteady vortical flows, (ii) particle laden and interfacial flows, (iii)molecular dynamics studies of nanoscale droplets and studies of the structure, functions, and evolution of the earliest living cell. The unifying computational approach involves particle methods implemented in parallel computer architectures. The inherent adaptivity, robustness and efficiency of particle methods makes them a multidisciplinary computational tool capable of bridging the gap of micro-scale and continuum flow simulations. Using efficient tree data structures, multipole expansion algorithms, and improved particle-grid interpolation, particle methods allow for simulations using millions of computational elements, making possible the resolution of a wide range of length and time scales of these important physical phenomena.The current challenges in these simulations are in : [i] the proper formulation of particle methods in the molecular and continuous level for the discretization of the governing equations [ii] the resolution of the wide range of time and length scales governing the phenomena under investigation. [iii] the minimization of numerical artifacts that may interfere with the physics of the systems under consideration. [iv] the parallelization of processes such as tree traversal and grid-particle interpolations We are conducting simulations using vortex methods, molecular dynamics and smooth particle hydrodynamics, exploiting their unifying concepts such as : the solution of the N-body problem in parallel computers, highly accurate particle-particle and grid-particle interpolations, parallel FFT's and the formulation of processes such as diffusion in the context of particle methods. This approach enables us to transcend among seemingly unrelated areas of research.

The Role of Perspective Taking in How Children Connect Reference Frames When Explaining Astronomical Phenomena

ERIC Educational Resources Information Center

Plummer, Julia D.; Bower, Corinne A.; Liben, Lynn S.

2016-01-01

This study investigates the role of perspective-taking skills in how children explain spatially complex astronomical phenomena. Explaining many astronomical phenomena, especially those studied in elementary and middle school, requires shifting between an Earth-based description of the phenomena and a space-based reference frame. We studied 7- to…

Review of Portable and Low-Cost Sensors for the Ambient Air Monitoring of Benzene and Other Volatile Organic Compounds

PubMed Central

Kok, Gertjan; Persijn, Stefan; Sauerwald, Tilman

2017-01-01

This article presents a literature review of sensors for the monitoring of benzene in ambient air and other volatile organic compounds. Combined with information provided by stakeholders, manufacturers and literature, the review considers commercially available sensors, including PID-based sensors, semiconductor (resistive gas sensors) and portable on-line measuring devices as for example sensor arrays. The bibliographic collection includes the following topics: sensor description, field of application at fixed sites, indoor and ambient air monitoring, range of concentration levels and limit of detection in air, model descriptions of the phenomena involved in the sensor detection process, gaseous interference selectivity of sensors in complex VOC matrix, validation data in lab experiments and under field conditions. PMID:28657595

Review of Portable and Low-Cost Sensors for the Ambient Air Monitoring of Benzene and Other Volatile Organic Compounds.

PubMed

Spinelle, Laurent; Gerboles, Michel; Kok, Gertjan; Persijn, Stefan; Sauerwald, Tilman

2017-06-28

This article presents a literature review of sensors for the monitoring of benzene in ambient air and other volatile organic compounds. Combined with information provided by stakeholders, manufacturers and literature, the review considers commercially available sensors, including PID-based sensors, semiconductor (resistive gas sensors) and portable on-line measuring devices as for example sensor arrays. The bibliographic collection includes the following topics: sensor description, field of application at fixed sites, indoor and ambient air monitoring, range of concentration levels and limit of detection in air, model descriptions of the phenomena involved in the sensor detection process, gaseous interference selectivity of sensors in complex VOC matrix, validation data in lab experiments and under field conditions.

Wave Phenomena in an Acoustic Resonant Chamber

ERIC Educational Resources Information Center

Smith, Mary E.; And Others

1974-01-01

Discusses the design and operation of a high Q acoustical resonant chamber which can be used to demonstrate wave phenomena such as three-dimensional normal modes, Q values, densities of states, changes in the speed of sound, Fourier decomposition, damped harmonic oscillations, sound-absorbing properties, and perturbation and scattering problems.…

Fluid Physical and Transport Phenomena Studies aboard the International Space Station: Planned Experiments

NASA Technical Reports Server (NTRS)

Singh, Bhim S.

1999-01-01

This paper provides an overview of the microgravity fluid physics and transport phenomena experiments planned for the International Spare Station. NASA's Office of Life and Microgravity Science and Applications has established a world-class research program in fluid physics and transport phenomena. This program combines the vast expertise of the world research community with NASA's unique microgravity facilities with the objectives of gaining new insight into fluid phenomena by removing the confounding effect of gravity. Due to its criticality to many terrestrial and space-based processes and phenomena, fluid physics and transport phenomena play a central role in the NASA's Microgravity Program. Through widely publicized research announcement and well established peer-reviews, the program has been able to attract a number of world-class researchers and acquired a critical mass of investigations that is now adding rapidly to this field. Currently there arc a total of 106 ground-based and 20 candidate flight principal investigators conducting research in four major thrust areas in the program: complex flows, multiphase flow and phase change, interfacial phenomena, and dynamics and instabilities. The International Space Station (ISS) to be launched in 1998, provides the microgravity research community with a unprecedented opportunity to conduct long-duration microgravity experiments which can be controlled and operated from the Principal Investigators' own laboratory. Frequent planned shuttle flights to the Station will provide opportunities to conduct many more experiments than were previously possible. NASA Lewis Research Center is in the process of designing a Fluids and Combustion Facility (FCF) to be located in the Laboratory Module of the ISS that will not only accommodate multiple users but, allow a broad range of fluid physics and transport phenomena experiments to be conducted in a cost effective manner.

Foot anthropometry and morphology phenomena.

PubMed

Agić, Ante; Nikolić, Vasilije; Mijović, Budimir

2006-12-01

Foot structure description is important for many reasons. The foot anthropometric morphology phenomena are analyzed together with hidden biomechanical functionality in order to fully characterize foot structure and function. For younger Croatian population the scatter data of the individual foot variables were interpolated by multivariate statistics. Foot structure descriptors are influenced by many factors, as a style of life, race, climate, and things of the great importance in human society. Dominant descriptors are determined by principal component analysis. Some practical recommendation and conclusion for medical, sportswear and footwear practice are highlighted.

Thermal modelling and control of 130kw direct contact (salt/air) heat exchanger

NASA Astrophysics Data System (ADS)

Qureshi, Omer A.; Calvet, Nicolas; Armstrong, Peter R.

2017-06-01

This work investigates the transient response of a certain type of direct contact heat exchanger (DCHX) that consists of packing (Raschig Rings) to increase the surface area for effective heat transfer between molten salt and air. Molten salt from the hot tank enters the heat exchanger (HX) and exit after heating the air still in the molten form. Thermal capacitance of the HX, mainly due to packing and resident salt inside the HX, results in strong transient response. Pure delay from salt residence time may also impact transient response. Both phenomena have been modelled in this paper. A Proportional-Integral controller (PI control) performance has been evaluated to maintain the minimum salt temperature above avoid crystallization temperature of the salt.

Meteorological determinants of air quality

NASA Astrophysics Data System (ADS)

Turoldo, F.; Del Frate, S.; Gallai, I.; Giaiotti, D. B.; Montanari, F.; Stel, F.; Goi, D.

2010-09-01

Air quality is the result of complex phenomena, among which the major role is played by human emissions of pollutants. Atmospheric processes act as determinants, e.g., modulating, dumping or amplifying the effects of emissions as an orchestra's director does with musical instruments. In this work, a series of small-scale and meso-scale meteorological determinants of air-quality are presented as they are observed in an area characterized by complex orography (Friuli Venezia Giulia, in the north-eastern side of Italy). In particular, attention is devoted to: i) meso-scale flows favouring the persistence of high concentrations of particulate matter; ii) meso-scale periodic flows (breezes) favouring high values of particulate matter; iii) local-scale thermodynamic behaviour favouring high atmospheric values of nitrogen oxides. The effects of these different classes of determinants are shown through comparisons between anthropic emissions (mainly traffic) and ground-based measurements. The relevance of complex orography (relatively steep relieves near to the sea) is shown for the meso-scale flows and, in particular, for local-scale periodic flows, which favour the increase of high pollutants concentrations mainly in summer, when the breezes regime is particularly relevant. Part of these results have been achieved through the ETS - Alpine Space EU project iMONITRAF!

Numerical simulation of anomalous wave phenomena in hot nuclear matter

NASA Astrophysics Data System (ADS)

Konyukhov, A. V.; Likhachev, A. P.

2015-11-01

The collective dynamic phenomena accompanying the collision of high-energy heavy ions are suggested to be approximately described in the framework of ideal relativistic hydrodynamics. If the transition from hadron state to quark-gluon plasma is the first-order phase transition (presently this view is prevailing), the hydrodynamic description of the nuclear matter must demonstrate several anomalous wave phenomena—such as the shock splitting and the formation of rarefaction shock and composite waves, which may be indicative of this transition. The present work is devoted to numerical study of these phenomena.

Sensory phenomena related to tics, obsessive-compulsive symptoms, and global functioning in Tourette syndrome.

PubMed

Kano, Yukiko; Matsuda, Natsumi; Nonaka, Maiko; Fujio, Miyuki; Kuwabara, Hitoshi; Kono, Toshiaki

2015-10-01

Sensory phenomena, including premonitory urges, are experienced by patients with Tourette syndrome (TS) and obsessive-compulsive disorder (OCD). The goal of the present study was to investigate such phenomena related to tics, obsessive-compulsive symptoms (OCS), and global functioning in Japanese patients with TS. Forty-one patients with TS were assessed using the University of São Paulo Sensory Phenomena Scale (USP-SPS), the Premonitory Urge for Tics Scale (PUTS), the Yale Global Tic Severity Scale (YGTSS), the Dimensional Yale-Brown Obsessive-Compulsive Scale (DY-BOCS), and the Global Assessment of Functioning (GAF) Scale. USP-SPS and PUTS total scores were significantly correlated with YGTSS total and vocal tics scores. Additionally, both sensory phenomena severity scores were significantly correlated with DY-BOCS total OCS scores. Of the six dimensional OCS scores, the USP-SPS scores were significantly correlated with measures of aggression and sexual/religious dimensions. Finally, the PUTS total scores were significantly and negatively correlated with GAF scores. By assessing premonitory urges and broader sensory phenomena, and by viewing OCS from a dimensional approach, this study provides significant insight into sensory phenomena related to tics, OCS, and global functioning in patients with TS. Copyright © 2015 Elsevier Inc. All rights reserved.

Temporal Phenomena in the Korean Conjunctive Constructions

ERIC Educational Resources Information Center

Kim, Dongmin

2015-01-01

The goal of this study is to characterize the temporal phenomena in the Korean conjunctive constructions. These constructions consist of three components: a verbal stem, a clause medial temporal suffix, and a clause terminal suffix. This study focuses on both the temporality of the terminal connective suffixes and the grammatical meanings of the…

Large-scale phenomena, chapter 3, part D

NASA Technical Reports Server (NTRS)

1975-01-01

Oceanic phenomena with horizontal scales from approximately 100 km up to the widths of the oceans themselves are examined. Data include: shape of geoid, quasi-stationary anomalies due to spatial variations in sea density and steady current systems, and the time dependent variations due to tidal and meteorological forces and to varying currents.

"Did You Climax or Are You Just Laughing at Me?" Rare Phenomena Associated With Orgasm.

PubMed

Reinert, Anna E; Simon, James A

2017-07-01

The study of the human orgasm has shown a core set of physiologic and psychological symptoms experienced by most individuals. The study of normal sheds light on the abnormal and has spotlighted rare physical and psychological symptoms experienced by some individuals in association with orgasm. These phenomena are rare and, as is typical of rare phenomena, their documentation in the medical literature is largely confined to case studies. To identify peri-orgasmic phenomena, defined as unusual physical or psychological symptoms subjectively experienced by some individuals as part of the orgasm response, distinct from the usual or normal orgasm response. A list of peri-orgasmic phenomena was made with help from sexual health colleagues and, using this list as a foundation, a literature search was performed of articles published in English. Publications included in this review report on physical or psychological phenomena at the time of orgasm that are distinct from psychological, whole-body, and genito-pelvic sensations commonly experienced at the time of orgasm. Cases of physical symptoms related to the physiology of sexual intercourse and not specifically to orgasm were excluded. Case studies of peri-orgasmic phenomena were reviewed, including cases describing cataplexy (weakness), crying, dysorgasmia, dysphoria, facial and/or ear pain, foot pain, headache, pruritus, laughter, panic attack, post-orgasm illness syndrome, seizures, and sneezing. The literature review confirms the existence of diverse and frequently replicated peri-orgasmic phenomena. The value of case studies is in the collection and recording of observations so that hypotheses can be formed about the observed phenomena. Accordingly, this review could inspire further research on the neurophysiologic mechanisms of orgasm. Reinert AE, Simon JA. "Did You Climax or Are You Just Laughing at Me?" Rare Phenomena Associated With Orgasm. Sex Med Rev 2017;5:275-281. Copyright © 2017 International Society for

Scaling phenomena in the Internet: Critically examining criticality

PubMed Central

Willinger, Walter; Govindan, Ramesh; Jamin, Sugih; Paxson, Vern; Shenker, Scott

2002-01-01

Recent Internet measurements have found pervasive evidence of some surprising scaling properties. The two we focus on in this paper are self-similar scaling in the burst patterns of Internet traffic and, in some contexts, scale-free structure in the network's interconnection topology. These findings have led to a number of proposed models or “explanations” of such “emergent” phenomena. Many of these explanations invoke concepts such as fractals, chaos, or self-organized criticality, mainly because these concepts are closely associated with scale invariance and power laws. We examine these criticality-based explanations of self-similar scaling behavior—of both traffic flows through the Internet and the Internet's topology—to see whether they indeed explain the observed phenomena. To do so, we bring to bear a simple validation framework that aims at testing whether a proposed model is merely evocative, in that it can reproduce the phenomenon of interest but does not necessarily capture and incorporate the true underlying cause, or indeed explanatory, in that it also captures the causal mechanisms (why and how, in addition to what). We argue that the framework can provide a basis for developing a useful, consistent, and verifiable theory of large networks such as the Internet. Applying the framework, we find that, whereas the proposed criticality-based models are able to produce the observed “emergent” phenomena, they unfortunately fail as sound explanations of why such scaling behavior arises in the Internet. PMID:11875212

Assessment of precursory information in seismo-electromagnetic phenomena

NASA Astrophysics Data System (ADS)

Han, P.; Hattori, K.; Zhuang, J.

2017-12-01

Previous statistical studies showed that there were correlations between seismo-electromagnetic phenomena and sizeable earthquakes in Japan. In this study, utilizing Molchan's error diagram, we evaluate whether these phenomena contain precursory information and discuss how they can be used in short-term forecasting of large earthquake events. In practice, for given series of precursory signals and related earthquake events, each prediction strategy is characterized by the leading time of alarms, the length of alarm window, the alarm radius (area) and magnitude. The leading time is the time length between a detected anomaly and its following alarm, and the alarm window is the duration that an alarm lasts. The alarm radius and magnitude are maximum predictable distance and minimum predictable magnitude of earthquake events, respectively. We introduce the modified probability gain (PG') and the probability difference (D') to quantify the forecasting performance and to explore the optimal prediction parameters for a given electromagnetic observation. The above methodology is firstly applied to ULF magnetic data and GPS-TEC data. The results show that the earthquake predictions based on electromagnetic anomalies are significantly better than random guesses, indicating the data contain potential useful precursory information. Meanwhile, we reveal the optimal prediction parameters for both observations. The methodology proposed in this study could be also applied to other pre-earthquake phenomena to find out whether there is precursory information, and then on this base explore the optimal alarm parameters in practical short-term forecast.

Preface: cardiac control pathways: signaling and transport phenomena.

PubMed

Sideman, Samuel

2008-03-01

Signaling is part of a complex system of communication that governs basic cellular functions and coordinates cellular activity. Transfer of ions and signaling molecules and their interactions with appropriate receptors, transmembrane transport, and the consequent intracellular interactions and functional cellular response represent a complex system of interwoven phenomena of transport, signaling, conformational changes, chemical activation, and/or genetic expression. The well-being of the cell thus depends on a harmonic orchestration of all these events and the existence of control mechanisms that assure the normal behavior of the various parameters involved and their orderly expression. The ability of cells to sustain life by perceiving and responding correctly to their microenvironment is the basis for development, tissue repair, and immunity, as well as normal tissue homeostasis. Natural deviations, or human-induced interference in the signaling pathways and/or inter- and intracellular transport and information transfer, are responsible for the generation, modulation, and control of diseases. The present overview aims to highlight some major topics of the highly complex cellular information transfer processes and their control mechanisms. Our goal is to contribute to the understanding of the normal and pathophysiological phenomena associated with cardiac functions so that more efficient therapeutic modalities can be developed. Our objective in this volume is to identify and enhance the study of some basic passive and active physical and chemical transport phenomena, physiological signaling pathways, and their biological consequences.

A Numerical Simulation of Transport Phenomena During the Horizontal Single Belt Casting Process Using an Inclined Feeding System

NASA Astrophysics Data System (ADS)

Xu, Mianguang; Isac, Mihaiela; Guthrie, Roderick I. L.

2018-03-01

Horizontal single belt casting (HSBC) has great potential to replace current conventional continuous casting (CCC) processes for sheet metal production, by directly casting 3 to 1 mm sheet for the automobile industry. In the present paper, two-dimensional mathematical models were developed to study transport phenomena, for the case of an inclined wall feeding system for a liquid aluminum wrought alloy (AA6111). Based on the commercial software ANSYS FLUENT 14.5 and user-defined functions, a two-layer turbulence model was used to examine the fluid flow emanating from a slot nozzle set above a water-cooled, high-speed, steel belt. The Volume of Fluid (VOF) method was used to predict the shape of the melt-air interface. A transformed coordinate system (x', y') was established in order to analyze the fluid flow on the inclined wall of the feeding system. The total pressure gauge gradient (∂p total/∂x) was used to describe the behavior of the melt film inside the slot nozzle of the head box. The modeling results show that during the melt film falling process, the total gauge pressure varies within the slot nozzle, which can decrease the stability of the falling film. The first impingement between the falling film and the inclined refractory wall of the feeding system gives rise to a local oscillation, and this influences the stability of the melt film moving downwards. At the rear meniscus position between the inclined wall and the moving belt, there is a clear vibration of the air-melt interface, together with a recirculation zone. The weak vibration of the air-melt interface could be induced by the periodic variation of the melt-air interface. Moreover, the formation of tiny air pockets is predicted. Finally, on the inclined wall of the feeding system, a suitable length of the transition area is needed to avoid over-acceleration of the melt film due to the force of gravity.

A Numerical Simulation of Transport Phenomena During the Horizontal Single Belt Casting Process Using an Inclined Feeding System

NASA Astrophysics Data System (ADS)

Xu, Mianguang; Isac, Mihaiela; Guthrie, Roderick I. L.

2018-06-01

Horizontal single belt casting (HSBC) has great potential to replace current conventional continuous casting (CCC) processes for sheet metal production, by directly casting 3 to 1 mm sheet for the automobile industry. In the present paper, two-dimensional mathematical models were developed to study transport phenomena, for the case of an inclined wall feeding system for a liquid aluminum wrought alloy (AA6111). Based on the commercial software ANSYS FLUENT 14.5 and user-defined functions, a two-layer turbulence model was used to examine the fluid flow emanating from a slot nozzle set above a water-cooled, high-speed, steel belt. The Volume of Fluid (VOF) method was used to predict the shape of the melt-air interface. A transformed coordinate system ( x', y') was established in order to analyze the fluid flow on the inclined wall of the feeding system. The total pressure gauge gradient ( ∂p total/ ∂x) was used to describe the behavior of the melt film inside the slot nozzle of the head box. The modeling results show that during the melt film falling process, the total gauge pressure varies within the slot nozzle, which can decrease the stability of the falling film. The first impingement between the falling film and the inclined refractory wall of the feeding system gives rise to a local oscillation, and this influences the stability of the melt film moving downwards. At the rear meniscus position between the inclined wall and the moving belt, there is a clear vibration of the air-melt interface, together with a recirculation zone. The weak vibration of the air-melt interface could be induced by the periodic variation of the melt-air interface. Moreover, the formation of tiny air pockets is predicted. Finally, on the inclined wall of the feeding system, a suitable length of the transition area is needed to avoid over-acceleration of the melt film due to the force of gravity.

Role of air-water interfaces in colloid transport in porous media: A review

NASA Astrophysics Data System (ADS)

Flury, Markus; Aramrak, Surachet

2017-07-01

Air-water interfaces play an important role in unsaturated porous media, giving rise to phenomena like capillarity. Less recognized and understood are interactions of colloids with the air-water interface in porous media and the implications of these interactions for fate and transport of colloids. In this review, we discuss how colloids, both suspended in the aqueous phase and attached at pore walls, interact with air-water interfaces in porous media. We discuss the theory of colloid/air-water interface interactions, based on the different forces acting between colloids and the air-water interface (DLVO, hydrophobic, capillary forces) and based on thermodynamic considerations (Gibbs free energy). Subsurface colloids are usually electrostatically repelled from the air-water interface because most subsurface colloids and the air-water are negatively charged. However, hydrophobic interactions can lead to attraction to the air-water interface. When colloids are at the air-water interface, capillary forces are usually dominant over other forces. Moving air-water interfaces are effective in mobilizing and transporting colloids from surfaces. Thermodynamic considerations show that, for a colloid, the air-water interface is the favored state as compared with the suspension phase, except for hydrophilic colloids in the nanometer size range. Experimental evidence indicates that colloid mobilization in soils often occurs through macropores, although matrix transport is also prevalent in absence of macropores. Moving air-water interfaces, e.g., occurring during infiltration, imbibition, or drainage, have been shown to scour colloids from surfaces and translocate colloids. Colloids can also be pinned to surfaces by thin water films and capillary menisci at the air-water-solid interface line, causing colloid retention and immobilization. Air-water interfaces thus can both mobilize or immobilize colloids in porous media, depending on hydrodynamics and colloid and surface

Calibration of low-cost gas sensors for an urban air quality monitoring network

NASA Astrophysics Data System (ADS)

Scott, A.; Kelley, C.; He, C.; Ghugare, P.; Lehman, A.; Benish, S.; Stratton, P.; Dickerson, R. R.; Zuidema, C.; Azdoud, Y.; Ren, X.

2017-12-01

In a warming world, environmental pollution may be exacerbated by anthropogenic activities, such as climate change and the urban heat island effect, as well as natural phenomena such as heat waves. However, monitoring air pollution at federal reference standards (approximately 1 part per billion or ppb for ambient ozone) is cost-prohibitive in heterogeneous urban areas as many expensive devices are required to fully capture a region's geo-spatial variability. Innovation in low-cost sensors provide a potential solution, yet technical challenges remain to overcome possible imprecision in the data. We present the calibrations of ozone and nitrous dioxide from a low-cost air quality monitoring device designed for the Baltimore Open Air Project. The sensors used in this study are commercially available thin film electrochemical sensors from SPEC Sensor, which are amperometric, meaning they generate current proportional to volumetric fraction of gas. The results of sensor calibrations in the laboratory and field are presented.

A comparison study of exploding a Cu wire in air, water, and solid powders

NASA Astrophysics Data System (ADS)

Han, Ruoyu; Wu, Jiawei; Ding, Weidong; Zhou, Haibin; Qiu, Aici; Wang, Yanan

2017-11-01

In this paper, an experimental study on exploding a copper wire in air, water, incombustible powders, and energetic materials is performed. We examined the effects of the surrounding media on the explosion process and its related phenomena. Experiments were first carried out with copper wire explosions driven by microsecond timescale pulsed currents in air, water, and the half-half case. Then, the copper wires were exploded in air, water, SiO2 powders, quartz sand, NaCl powders, and energetic-material cylinders, respectively. Our experimental results indicated that the explosion process was significantly influenced by the surrounding media, resulting in noticeable differences in energy deposition, optical emission, and shock waves. In particular, incombustible powders could throttle the current flow completely when a fine wire was adopted. We also found that an air or incombustible-powder layer could drastically attenuate the shock wave generated by a wire explosion. As for energetic-material loads, obvious discrepancies were found in voltage/current waveforms from vaporization when compared with a wire explosion in air/water, which meant the metal vapor/liquid drops play a significant role in the ignition process.

Merging Air Quality and Public Health Decision Support Systems

NASA Astrophysics Data System (ADS)

Hudspeth, W. B.; Bales, C. L.

2003-12-01

The New Mexico Air Quality Mapper (NMAQM) is a Web-based, open source GIS prototype application that Earth Data Analysis Center is developing under a NASA Cooperative Agreement. NMAQM enhances and extends existing data and imagery delivery systems with an existing Public Health system called the Rapid Syndrome Validation Project (RSVP). RSVP is a decision support system operating in several medical and public health arenas. It is evolving to ingest remote sensing data as input to provide early warning of human health threats, especially those related to anthropogenic atmospheric pollutants and airborne pathogens. The NMAQM project applies measurements of these atmospheric pollutants, derived from both remotely sensed data as well as from in-situ air quality networks, to both forecasting and retrospective analyses that influence human respiratory health. NMAQM provides a user-friendly interface for visualizing and interpreting environmentally-linked epidemiological phenomena. The results, and the systems made to provide the information, will be applicable not only to decision-makers in the public health realm, but also to air quality organizations, demographers, community planners, and other professionals in information technology, and social and engineering sciences. As an accessible and interactive mapping and analysis application, it allows environment and health personnel to study historic data for hypothesis generation and trend analysis, and then, potentially, to predict air quality conditions from daily data acquisitions. Additional spin off benefits to such users include the identification of gaps in the distribution of in-situ monitoring stations, the dissemination of air quality data to the public, and the discrimination of local vs. more regional sources of air pollutants that may bear on decisions relating to public health and public policy.

Understanding the coherence of the severity effect and optimism phenomena: Lessons from attention.

PubMed

Harris, Adam J L

2017-04-01

Claims that optimism is a near-universal characteristic of human judgment seem to be at odds with recent results from the judgment and decision making literature suggesting that the likelihood of negative outcomes are overestimated relative to neutral outcomes. In an attempt to reconcile these seemingly contrasting phenomena, inspiration is drawn from the attention literature in which there is evidence that both positive and negative stimuli can have attentional privilege relative to neutral stimuli. This result provides a framework within which I consider three example phenomena that purport to demonstrate that people's likelihood estimates are optimistic: Wishful thinking; Unrealistic comparative optimism and Asymmetric belief updating. The framework clarifies the relationships between these phenomena and stimulates future research questions. Generally, whilst results from the first two phenomena appear reconcilable in this conceptualisation, further research is required in reconciling the third. Copyright © 2016 Elsevier Inc. All rights reserved.

Theoretical Studies of Nonlinear Phenomena in Plasmas.

DTIC Science & Technology

1984-02-14

AD-Ai38 762 THEORETICAL STUDIES OF NONLINEAR PHENOMENA IN PLASMAS i/i, (U) MARYLAND UNIV COLLEUE FHRK LAB FOR PLASMA AND FUSION ENERGY STUDIES H H...Tnvestiga-tor: H. Chen 4 j DTIC $ELECTE ~ ~.UNIVERSITY OF MARYLAND * S 4ABORATORY FOR PLASMA AND FUSION ENERGY STUDIES " ’ ..COLLEGE PARK, MARYLAND 4k

Physics education students’ cognitive and affective domains toward ecological phenomena

NASA Astrophysics Data System (ADS)

Napitupulu, N. D.; Munandar, A.; Redjeki, S.; Tjasyono, B.

2018-05-01

Environmental education is become prominent in dealing with natural phenomena that occur nowadays. Studying environmental physics will lead students to have conceptual understanding which are importent in enhancing attitudes toward ecological phenomena that link directry to cognitive and affective domains. This research focused on the the relationship of cognitive and affective domains toward ecological phenomena. Thirty-seven Physics Education students participated in this study and validated sources of data were collected to eksplore students’ conceptual understanding as cognitive domain and to investigate students’ attitudes as affective domain. The percentage of cognitive outcome and affective outcome are explore. The features of such approaches to environmental learning are discussion through analysis of contribution of cognitive to develop the attitude ecological as affective outcome. The result shows that cognitive domains do not contribute significantly to affective domain toward ecological henomena as an issue trend in Central Sulawesi although students had passed Environmental Physics instruction for two semester. In fact, inferior knowledge in a way actually contributes to the attitude domain caused by the prior knowledge that students have as ombo as a Kaili local wisdom.

Complex (dusty) plasmas-kinetic studies of strong coupling phenomena

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

Morfill, Gregor E.; Ivlev, Alexei V.; Thomas, Hubertus M.

2012-05-15

'Dusty plasmas' can be found almost everywhere-in the interstellar medium, in star and planet formation, in the solar system in the Earth's atmosphere, and in the laboratory. In astrophysical plasmas, the dust component accounts for only about 1% of the mass, nevertheless this component has a profound influence on the thermodynamics, the chemistry, and the dynamics. Important physical processes are charging, sputtering, cooling, light absorption, and radiation pressure, connecting electromagnetic forces to gravity. Surface chemistry is another important aspect. In the laboratory, there is great interest in industrial processes (e.g., etching, vapor deposition) and-at the fundamental level-in the physics ofmore » strong coupling phenomena. Here, the dust (or microparticles) are the dominant component of the multi-species plasma. The particles can be observed in real time and space, individually resolved at all relevant length and time scales. This provides an unprecedented means for studying self-organisation processes in many-particle systems, including the onset of cooperative phenomena. Due to the comparatively large mass of the microparticles (10{sup -12}to10{sup -9}g), precision experiments are performed on the ISS. The following topics will be discussed: Phase transitions, phase separation, electrorheology, flow phenomena including the onset of turbulence at the kinetic level.« less

Thermo-Chemical Phenomena Simulation for Ablation

DTIC Science & Technology

2011-02-21

DATES COVERED (1/01/08-30/11/10) 4. TITLE AND SUBTITLE Thermo- Chemical Phenomena Simulation for Ablation 5a. CONTRACT NUMBER...First, a physic based chemical kinetic model for high-temperature gas is developed and verified by comparing with data from the RAM-C-II probe and the...found to be negligible and the energy exchange is dominated by the chemical process for conductive-convective heat transfer. A simplified and more

Probing Cytological and Reproductive Phenomena by Means of Bryophytes.

ERIC Educational Resources Information Center

Newton, M. E.

1985-01-01

Describes procedures (recommended for both secondary and college levels) to study mitosis, Giemsa C-banding, reproductive phenomena (including alternation of generations), and phototropism in mosses and liverworts. (JN)

Autoimmune phenomena following prostatectomy.

PubMed

Tweezer-Zaks, Nurit; Marai, Ibrahim; Livneh, Avi; Bank, Ilan; Langevitz, Pnina

2005-09-01

Benign prostatic hypertrophy is the most common benign tumor in males, resulting in prostatectomy in 20-30% of men who live to the age of 80. There are no data on the association of prostatectomy with autoimmune phenomena in the English-language medical literature. To report our experience with three patients who developed autoimmune disease following prostatectomy. Three patients presented awith autoimmune phenomenon soon after a prostectomy for BPH or prostatic carcinoma: one had clinically diagnosed temporal arteritis, one had leukocytoclastic vasculitis, and the third patient developed sensory Guillian-Barré syndrome following prostatectomy. In view of the temporal association between the removal of the prostate gland andthe autoimmune process, combined with previously known immunohistologic features of BPH, a cause-effect relationship probably exists.

ATV Ingress

NASA Image and Video Library

2014-08-13

ISS040-E-091921 (13 Aug. 2014) --- European Space Agency astronaut Alexander Gerst, Expedition 40 flight engineer, prepares to remove the docking mechanism to gain access to the hatch of the newly attached "Georges Lemaitre" Automated Transfer Vehicle-5 (ATV-5).

ATV Ingress

NASA Image and Video Library

2014-08-13

ISS040-E-091940 (13 Aug. 2014) --- Russian cosmonaut Alexander Skvortsov, Expedition 40 flight engineer, prepares to remove the docking mechanism to gain access to the hatch of the newly attached "Georges Lemaitre" Automated Transfer Vehicle-5 (ATV-5).

ATV Ingress

NASA Image and Video Library

2014-08-13

ISS040-E-091918 (13 Aug. 2014) --- European Space Agency astronaut Alexander Gerst, Expedition 40 flight engineer, prepares to remove the docking mechanism to gain access to the hatch of the newly attached "Georges Lemaitre" Automated Transfer Vehicle-5 (ATV-5).

ATV Ingress

NASA Image and Video Library

2014-08-13

ISS040-E-091919 (13 Aug. 2014) --- European Space Agency astronaut Alexander Gerst, Expedition 40 flight engineer, prepares to remove the docking mechanism to gain access to the hatch of the newly attached "Georges Lemaitre" Automated Transfer Vehicle-5 (ATV-5).

ATV Ingress

NASA Image and Video Library

2014-08-13

ISS040-E-091922 (13 Aug. 2014) --- European Space Agency astronaut Alexander Gerst, Expedition 40 flight engineer, prepares to remove the docking mechanism to gain access to the hatch of the newly attached "Georges Lemaitre" Automated Transfer Vehicle-5 (ATV-5).

ATV Ingress

NASA Image and Video Library

2014-08-13

ISS040-E-091979 (13 Aug. 2014) --- European Space Agency astronaut Alexander Gerst, Expedition 40 flight engineer, is pictured in the hatch after removing the docking mechanism of the newly-attached "Georges Lemaitre" Automated Transfer Vehicle-5 (ATV-5) of the International Space Station.

ATV Ingress

NASA Image and Video Library

2014-08-13

ISS040-E-091966 (13 Aug. 2014) --- European Space Agency astronaut Alexander Gerst, Expedition 40 flight engineer, is pictured in the newly-attached "Georges Lemaitre" Automated Transfer Vehicle-5 (ATV-5) of the International Space Station.

ATV Ingress

NASA Image and Video Library

2014-08-13

ISS040-E-091989 (13 Aug. 2014) --- European Space Agency astronaut Alexander Gerst, Expedition 40 flight engineer, enters the newly-attached "Georges Lemaitre" Automated Transfer Vehicle-5 (ATV-5) of the International Space Station.

ATV Ingress

NASA Image and Video Library

2014-08-13

ISS040-E-091969 (13 Aug. 2014) --- Surrounded by stowage containers, European Space Agency astronaut Alexander Gerst, Expedition 40 flight engineer, is pictured in the newly-attached "Georges Lemaitre" Automated Transfer Vehicle-5 (ATV-5) of the International Space Station.

Sundance Fire: an analysis of fire phenomena

Treesearch

Hal E. Anderson

1968-01-01

The Sundance Fire on September 1, 1967, made a spectacular run of 16 miles in 9 hours and destroyed more than 50,000 acres. This run became the subject of a detailed research analysis of the environmental, topographic, and vegetation variables aimed at reconstructing and describing fire phenomena. This report details the fire's progress; discusses the fire's...

Nonlinear phenomena in general relativity

NASA Astrophysics Data System (ADS)

Allahyari, Alireza; Firouzjaee, Javad T.; Mansouri, Reza

2018-04-01

The perturbation theory plays an important role in studying structure formation in cosmology and post-Newtonian physics, but not all phenomena can be described by the linear perturbation theory. Thus, it is necessary to study exact solutions or higher-order perturbations. Specifically, we study black hole (apparent) horizons and the cosmological event horizon formation in the perturbation theory. We emphasize that in the perturbative regime of the gravitational potential these horizons cannot form in the lower order. Studying the infinite plane metric, we show that, to capture the cosmological constant effect, we need at least a second-order expansion.

An experimental study of a plunging liquid jet induced air carryunder and dispersion

NASA Astrophysics Data System (ADS)

Bonetto, F.; Drew, D. A.; Lahey, R. T., Jr.

1993-03-01

A good understanding of the air carryunder and bubble dispersion process associated with a plunging liquid jet is vital if one is to be able to quantify such diverse phenomena as sea surface chemistry, the meteorological significance of breaking ocean waves (e.g., mitigation of the greenhouse effect due to the absorption of CO2 by the oceans), the performance of certain type of chemical reactors, and a number of other important maritime-related applications. The absorption of greenhouse gases into the ocean has been hypothesized to be highly dependent upon the air carryunder that occurs due to breaking waves. This process can be approximated with a plunging liquid jet. Moreover, the air entrainment process due to the breaking bow waves of surface ships may cause long (i.e., up to 5 km in length) wakes. Naturally, easily detectable wakes are undesirable for naval warships. In addition, the air carryunder that occurs at most hydraulic structures in rivers is primarily responsible for the large air/water mass transfer that is associated with these structures. Also, air entrainment plays an important role in the slug flow regime. In particular, the liquid film surrounding a Taylor bubble has a flow in the opposite direction from the Taylor bubble. This liquid film can be thought of as a plunging liquid jet that produces a surface depression in the rear part of the Taylor bubble.

Role of the Hof1-Cyk3 interaction in cleavage-furrow ingression and primary-septum formation during yeast cytokinesis.

PubMed

Wang, Meng; Nishihama, Ryuichi; Onishi, Masayuki; Pringle, John R

2018-03-01

In Saccharomyces cerevisiae, it is well established that Hof1, Cyk3, and Inn1 contribute to septum formation and cytokinesis. Because hof1∆ and cyk3∆ single mutants have relatively mild defects but hof1∆ cyk3∆ double mutants are nearly dead, it has been hypothesized that these proteins contribute to parallel pathways. However, there is also evidence that they interact physically. In this study, we examined this interaction and its functional significance in detail. Our data indicate that the interaction 1) is mediated by a direct binding of the Hof1 SH3 domain to a proline-rich motif in Cyk3; 2) occurs specifically at the time of cytokinesis but is independent of the (hyper)phosphorylation of both proteins that occurs at about the same time; 3) is dispensable for the normal localization of both proteins; 4) is essential for normal primary-septum formation and a normal rate of cleavage-furrow ingression; and 5) becomes critical for growth when either Inn1 or the type II myosin Myo1 (a key component of the contractile actomyosin ring) is absent. The similarity in phenotype between cyk3∆ mutants and mutants specifically lacking the Hof1-Cyk3 interaction suggests that the interaction is particularly important for Cyk3 function, but it may be important for Hof1 function as well. © 2018 Wang et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Some problems in coupling solar activity to meteorological phenomena

NASA Technical Reports Server (NTRS)

Dessler, A. J.

1975-01-01

The development of a theory of coupling of solar activity to meteorological phenomena is hindered by the difficulties of devising a mechanism that can modify the behavior of the troposphere while employing only a negligible amount of energy compared with the energy necessary to drive the normal meteorological system, and determining how such a mechanism can effectively couple some relevant magnetospheric process into the troposphere in such a way as to influence the weather. A clue to the nature of the interaction between the weather and solar activity might be provided by the fact that most solar activity undergoes a definite 11-yr cycle, and meteorological phenomena undergo either no closely correlated variation, an 11-yr variation, or a 22-yr variation.

Multispectral observations complementary to the study of high-energy solar phenomena

NASA Technical Reports Server (NTRS)

Walker, Arthur B. C., Jr.

1988-01-01

Multispectral observations of phenomena associated with nonthermal events on the sun and characterized by the transient acceleration of electrons and ions to energies ranging from several keV to tens of GeV are discussed. It is shown that observations of the thermal and quasi-thermal phenomena preceeding, coinciding with, and following the impulsive acceleration and heating event itself can be used to study the evolution of magnetic structures in the solar convection zone and atmosphere. Observational techniques are discussed in detail.

Proceedings of the Fourth Microgravity Fluid Physics and Transport Phenomena Conference

NASA Technical Reports Server (NTRS)

Singh, Bhim S. (Editor)

1999-01-01

This conference presents information to the scientific community on research results, future directions, and research opportunities in microgravity fluid physics and transport phenomena within NASA's microgravity research program. The conference theme is "The International Space Station." Plenary sessions provide an overview of the Microgravity Fluid Physics Program, the International Space Station and the opportunities ISS presents to fluid physics and transport phenomena researchers, and the process by which researchers may become involved in NASA's program, including information about the NASA Research Announcement in this area. Two plenary lectures present promising areas of research in electrohydrodynamics/electrokinetics in the movement of particles and in micro- and meso-scale effects on macroscopic fluid dynamics. Featured speakers in plenary sessions present results of recent flight experiments not heretofore presented. The conference publication consists of this book of abstracts and the full Proceedings of the 4th Microgravity Fluid Physics and Transport Phenomena Conference on CD-ROM, containing full papers presented at the conference (NASA/CP-1999-208526/SUPPL1).

Electro-Hydrodynamics and Kinetic Modeling of Dry and Humid Air Flows Activated by Corona Discharges

NASA Astrophysics Data System (ADS)

P. Sarrette, J.; Eichwald, O.; Marchal, F.; Ducasse, O.; Yousfi, M.

2016-05-01

The present work is devoted to the 2D simulation of a point-to-plane Atmospheric Corona Discharge Reactor (ACDR) powered by a DC high voltage supply. The corona reactor is periodically crossed by thin mono filamentary streamers with a natural repetition frequency of some tens of kHz. The study compares the results obtained in dry air and in air mixed with a small amount of water vapour (humid air). The simulation involves the electro-dynamics, chemical kinetics and neutral gas hydrodynamics phenomena that influence the kinetics of the chemical species transformation. Each discharge lasts about one hundred of a nanosecond while the post-discharge occurring between two successive discharges lasts one hundred of a microsecond. The ACDR is crossed by a lateral dry or humid air flow initially polluted with 400 ppm of NO. After 5 ms, the time corresponding to the occurrence of 50 successive discharge/post-discharge phases, a higher NO removal rate and a lower ozone production rate are found in humid air. This change is due to the presence of the HO2 species formed from the H primary radical in the discharge zone.

Neutronics Phenomena Important in Modeling and Simulation of Liquid-Fuel Molten Salt Reactors

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

Diamond, David J.

This paper discusses liquid-fuel molten salt reactors, how they will operate under normal, transient, and accident conditions, and the results of an expert elicitation to determine the corresponding neutronic phenomena important to understanding their behavior. Identifying these phenomena will enable the U.S. Nuclear Regulatory Commission (NRC) to develop or identify modeling functionalities and tools required to carry out confirmatory analyses that examine the validity and accuracy of applicants’ calculations and help determine the margin of safety in plant design. NRC frequently does an expert elicitation using a Phenomena Identification and Ranking Table (PIRT) to identify and evaluate the state ofmore » knowledge of important modeling phenomena. However, few details about the design of these reactors and the sequence of events during accidents are known, so the process used was considered a preliminary PIRT. A panel met to define phenomena that would need to be modeled and considered the impact/importance of each phenomenon with respect to specific figures-of-merit (FoMs) (e.g., power distribution, fluence, kinetics parameters and reactivity). Each FoM reflected a potential impact on radionuclide release or loss of a barrier to release. The panel considered what the path forward might be with respect to being able to model the phenomenon in a simulation code. Results are explained for both thermal and fast spectrum designs.« less

Physical phenomena and the microgravity response

NASA Technical Reports Server (NTRS)

Todd, Paul

1989-01-01

The living biological cell is not a sack of Newtonian fluid containing systems of chemical reactions at equilibrium. It is a kinetically driven system, not a thermodynamically driven system. While the cell as a whole might be considered isothermal, at the scale of individual macromolecular events there is heat generated, and presumably sharp thermal gradients exist at the submicron level. Basic physical phenomena to be considered when exploring the cell's response to inertial acceleration include particle sedimentation, solutal convection, motility electrokinetics, cytoskeletal work, and hydrostatic pressure. Protein crystal growth experiments, for example, illustrate the profound effects of convection currents on macromolecular assembly. Reaction kinetics in the cell vary all the way from diffusion-limited to life-time limited. Transport processes vary from free diffusion, to facilitated and active transmembrane transport, to contractile-protein-driven motility, to crystalline immobilization. At least four physical states of matter exist in the cell: aqueous, non-aqueous, immiscible-aqueous, and solid. Levels of order vary from crystalline to free solution. The relative volumes of these states profoundly influence the cell's response to inertial acceleration. Such subcellular phenomena as stretch-receptor activation, microtubule re-assembly, synaptic junction formation, chemotactic receptor activation, and statolith sedimentation were studied recently with respect to both their basic mechanisms and their responsiveness to inertial acceleration. From such studies a widespread role of cytoskeletal organization is becoming apparent.

Assessing Decreased Sensation and Increased Sensory Phenomena in Diabetic Polyneuropathies

PubMed Central

Herrmann, David N.; Staff, Nathan P.; Dyck, P. James B.

2013-01-01

Loss of sensation and increased sensory phenomena are major expressions of varieties of diabetic polyneuropathies needing improved assessments for clinical and research purposes. We provide a neurobiological explanation for the apparent paradox between decreased sensation and increased sensory phenomena. Strongly endorsed is the use of the 10-g monofilaments for screening of feet to detect sensation loss, with the goal of improving diabetic management and prevention of foot ulcers and neurogenic arthropathy. We describe improved methods to assess for the kind, severity, and distribution of both large- and small-fiber sensory loss and which approaches and techniques may be useful for conducting therapeutic trials. The abnormality of attributes of nerve conduction may be used to validate the dysfunction of large sensory fibers. The abnormality of epidermal nerve fibers/1 mm may be used as a surrogate measure of small-fiber sensory loss but appear not to correlate closely with severity of pain. Increased sensory phenomena are recognized by the characteristic words patients use to describe them and by the severity and persistence of these symptoms. Tests of tactile and thermal hyperalgesia are additional markers of neural hyperactivity that are useful for diagnosis and disease management. PMID:24158999

Fast soft x-ray images of magnetohydrodynamic phenomena in NSTX.

PubMed

Bush, C E; Stratton, B C; Robinson, J; Zakharov, L E; Fredrickson, E D; Stutman, D; Tritz, K

2008-10-01

A variety of magnetohydrodynamic (MHD) phenomena have been observed on NSTX. Many of these affect fast particle losses, which are of major concern for future burning plasma experiments. Usual diagnostics for studying these phenomena are arrays of Mirnov coils for magnetic oscillations and p-i-n diode arrays for soft x-ray emission from the plasma core. Data reported here are from a unique fast soft x-ray imaging camera (FSXIC) with a wide-angle (pinhole) tangential view of the entire plasma minor cross section. The camera provides a 64x64 pixel image, on a charge coupled device chip, of light resulting from conversion of soft x rays incident on a phosphor to the visible. We have acquired plasma images at frame rates of 1-500 kHz (300 frames/shot) and have observed a variety of MHD phenomena: disruptions, sawteeth, fishbones, tearing modes, and edge localized modes (ELMs). New data including modes with frequency >90 kHz are also presented. Data analysis and modeling techniques used to interpret the FSXIC data are described and compared, and FSXIC results are compared to Mirnov and p-i-n diode array results.

Regional Phenomena of Vertical Deformation in Southern Part of Indonesia

NASA Astrophysics Data System (ADS)

Sarsito, D. A.; Susilo; Andreas, H.; Pradipta, D.; Gumilar, I.

2018-02-01

Distribution of present-day horizontal and vertical deformation across the Southern Part of Indonesia at Java, Bali and Nusa Tenggara now days can be determined from continuous and campaign types of GNSS GPS data monitoring. For vertical deformation in this case we use the continuous types since they are give better quality of data consistency compare to campaign type. Continuous Global Positioning System (CGPS) are maintaining by Geospatial Information Agency for more than a decade. The vertical displacements or velocity rates are estimated from time series analysis after multi-baseline GPS processing using GAMIT-GLOBK software with respect to the latest International Terrestrial Reference Frame. The result shows some interesting phenomena where the northern part of research area majority have negative value that may indicate land subsidence with or without tectonic subsidence combination. In the middle part, the uplift phenomena are clearly shown and in the southern part show combine pattern between uplift and subsidence. The impacts of those phenomena would be discuss also in this paper since many population and infrastructure are located in the areas that will need more protection planning to reduce the negative impact such as earthquake and flooding.

Review of Natural Phenomena Hazard (NPH) Assessments for the Hanford 200 Areas (Non-Seismic)

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

Snow, Robert L.; Ross, Steven B.; Sullivan, Robin S.

2010-09-24

The purpose of this review is to assess the need for updating Natural Phenomena Hazard (NPH) assessments for the Hanford 200 Areas, as required by DOE Order 420.1B Chapter IV, Natural Phenomena Hazards Mitigation, based on significant changes in state-of-the-art NPH assessment methodology or site-specific information. The review includes all natural phenomena hazards with the exception of seismic/earthquake hazards, which are being addressed under a separate effort. It was determined that existing non-seismic NPH assessments are consistent with current design methodology and site specific data.

Some problems in coupling solar activity to meteorological phenomena

NASA Technical Reports Server (NTRS)

Dessler, A. J.

1974-01-01

The development of a theory of coupling of solar activity to meteorological phenomena has to date foundered on the two difficulties of (1) devising a mechanism that can modify the behavior of the troposphere while employing only a negligible amount of energy compared with the energy necessary to drive the normal meteorological system; and (2) determining how such a mechanism can effectively couple some relevant magnetospheric process into the troposphere in such a way as to influence the weather. A clue to the nature of the interaction between the weather and solar activity might be provided by the fact that most solar activity undergoes a definite 11-year cycle, while meteorological phenomena undergo either no closely correlated variation, or an 11-year variation, or a 22-year variation.

Concepts and methods for describing critical phenomena in fluids

NASA Technical Reports Server (NTRS)

Sengers, J. V.; Sengers, J. M. H. L.

1977-01-01

The predictions of theoretical models for a critical-point phase transistion in fluids, namely the classical equation with third-degree critical isotherm, that with fifth-degree critical isotherm, and the lattice gas, are reviewed. The renormalization group theory of critical phenomena and the hypothesis of universality of critical behavior supported by this theory are discussed as well as the nature of gravity effects and how they affect cricital-region experimentation in fluids. The behavior of the thermodynamic properties and the correlation function is formulated in terms of scaling laws. The predictions of these scaling laws and of the hypothesis of universality of critical behavior are compared with experimental data for one-component fluids and it is indicated how the methods can be extended to describe critical phenomena in fluid mixtures.

Sixth Microgravity Fluid Physics and Transport Phenomena Conference Abstracts

NASA Technical Reports Server (NTRS)

Singh, Bhim (Compiler)

2002-01-01

The Sixth Microgravity Fluid Physics and Transport Phenomena Conference provides the scientific community the opportunity to view the current scope of the Microgravity Fluid Physics and Transport Phenomena Program, current research opportunities, and plans for the near future. The conference focuses not only on fundamental research but also on applications of this knowledge towards enabling future space exploration missions. A whole session dedicated to biological fluid physics shows increased emphasis that the program has placed on interdisciplinary research. The conference includes invited plenary talks, technical paper presentations, poster presentations, and exhibits. This TM is a compilation of abstracts of the papers and the posters presented at the conference. Web-based proceedings, including the charts used by the presenters, will be posted on the web shortly after the conference.

Molecular Dynamics Study of the Bulk and Interface Properties of Frother and Oil with Saltwater and Air

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

Chong, Leebyn; Lai, Yungchieh; Gray, McMahan

For water treatment purposes, the separation processes involving surfactants and crude oil at seawater-air interfaces are of importance for chemical and energy industries. Little progress has been made in understanding the nanoscale phenomena of surfactants on oily saltwater-air interfaces. This work focuses on using molecular dynamics with a united-atom force field to simulate the interface of linear alkane oil, saltwater, and air with three surfactant frothers: methyl isobutyl carbinol (MIBC), terpineol, and ethyl glycol butyl ether (EGBE). For each frother, although the calculated diffusivities and viscosities are lower than the expected experimental values, our results showed that diffusivity trends betweenmore » each frother agree with experiments but was not suitable for viscosity. Binary combinations of liquid (frother or saltwater)-air and liquid-liquid interfaces are equilibrated to study the density profiles and interfacial tensions. The calculated surface tensions of the frothers-air interfaces are like that of oil-air, but lower than that of saltwater-air. Only MIBC-air and terpineol-air interfaces agreed with our experimental measurements. For frother-saltwater interfaces, the calculated results showed that terpineol has interfacial tensions higher than those of the MIBC-saltwater. Here, the simulated results indicated that the frother-oil systems underwent mixing such that the density profiles depicted large interfacial thicknesses.« less

Molecular Dynamics Study of the Bulk and Interface Properties of Frother and Oil with Saltwater and Air

DOE PAGES

Chong, Leebyn; Lai, Yungchieh; Gray, McMahan; ...

2017-03-15

For water treatment purposes, the separation processes involving surfactants and crude oil at seawater-air interfaces are of importance for chemical and energy industries. Little progress has been made in understanding the nanoscale phenomena of surfactants on oily saltwater-air interfaces. This work focuses on using molecular dynamics with a united-atom force field to simulate the interface of linear alkane oil, saltwater, and air with three surfactant frothers: methyl isobutyl carbinol (MIBC), terpineol, and ethyl glycol butyl ether (EGBE). For each frother, although the calculated diffusivities and viscosities are lower than the expected experimental values, our results showed that diffusivity trends betweenmore » each frother agree with experiments but was not suitable for viscosity. Binary combinations of liquid (frother or saltwater)-air and liquid-liquid interfaces are equilibrated to study the density profiles and interfacial tensions. The calculated surface tensions of the frothers-air interfaces are like that of oil-air, but lower than that of saltwater-air. Only MIBC-air and terpineol-air interfaces agreed with our experimental measurements. For frother-saltwater interfaces, the calculated results showed that terpineol has interfacial tensions higher than those of the MIBC-saltwater. Here, the simulated results indicated that the frother-oil systems underwent mixing such that the density profiles depicted large interfacial thicknesses.« less

The Effects of Globalization Phenomena on Educational Concepts

ERIC Educational Resources Information Center

Schrottner, Barbara Theresia

2010-01-01

It is becoming more and more apparent that globalization processes represent, theoretically as well as practically, a challenge for educational sciences and therefore, it must be addressed within the sphere of education. Accordingly, educational conceptions have to adapt to globalization phenomena and focus more on alternative and innovative…

Space Weather affects on Air Transportation

NASA Astrophysics Data System (ADS)

Jones, J. B. L.; Bentley, R. D.; Dyer, C.; Shaw, A.

In Europe, legislation requires the airline industry to monitor the occupational exposure of aircrew to cosmic radiation. However, there are other significant impacts of space weather phenomena on the technological systems used for day-to-day operations which need to be considered by the airlines. These were highlighted by the disruption caused to the industry by the period of significant solar activity in late October and early November 2003. Next generation aircraft will utilize increasingly complex avionics as well as expanding the performance envelopes. These and future generation platforms will require the development of a new air-space management infrastructure with improved position accuracy (for route navigation and landing in bad weather) and reduced separation minima in order to cope with the expected growth in air travel. Similarly, greater reliance will be placed upon satellites for command, control, communication and information (C3I) of the operation. However, to maximize effectiveness of this globally interoperable C3I and ensure seamless fusion of all components for a safe operation will require a greater understanding of the space weather affects, their risks with increasing technology, and the inclusion of space weather information into the operation. This paper will review space weather effects on air transport and the increasing risks for future operations cause by them. We will examine how well the effects can be predicted, some of the tools that can be used and the practicalities of using such predictions in an operational scenario. Initial results from the SOARS ESA Space Weather Pilot Project will also be discussed,

Contamination of current-clamp measurement of neuron capacitance by voltage-dependent phenomena

PubMed Central

White, William E.

2013-01-01

Measuring neuron capacitance is important for morphological description, conductance characterization, and neuron modeling. One method to estimate capacitance is to inject current pulses into a neuron and fit the resulting changes in membrane potential with multiple exponentials; if the neuron is purely passive, the amplitude and time constant of the slowest exponential give neuron capacitance (Major G, Evans JD, Jack JJ. Biophys J 65: 423–449, 1993). Golowasch et al. (Golowasch J, Thomas G, Taylor AL, Patel A, Pineda A, Khalil C, Nadim F. J Neurophysiol 102: 2161–2175, 2009) have shown that this is the best method for measuring the capacitance of nonisopotential (i.e., most) neurons. However, prior work has not tested for, or examined how much error would be introduced by, slow voltage-dependent phenomena possibly present at the membrane potentials typically used in such work. We investigated this issue in lobster (Panulirus interruptus) stomatogastric neurons by performing current clamp-based capacitance measurements at multiple membrane potentials. A slow, voltage-dependent phenomenon consistent with residual voltage-dependent conductances was present at all tested membrane potentials (−95 to −35 mV). This phenomenon was the slowest component of the neuron's voltage response, and failure to recognize and exclude it would lead to capacitance overestimates of several hundredfold. Most methods of estimating capacitance depend on the absence of voltage-dependent phenomena. Our demonstration that such phenomena make nonnegligible contributions to neuron responses even at well-hyperpolarized membrane potentials highlights the critical importance of checking for such phenomena in all work measuring neuron capacitance. We show here how to identify such phenomena and minimize their contaminating influence. PMID:23576698

ldentifying Episodes of Earth Science Phenomena Using a Big-Data Technology

NASA Technical Reports Server (NTRS)

Kuo, Kwo-Sen; Oloso, Amidu; Rushing, John; Lin, Amy; Fekete, Gyorgy; Ramachandran, Rahul; Clune, Thomas; Dunny, Daniel

2014-01-01

A significant portion of Earth Science investigations is phenomenon- (or event-) based, such as the studies of Rossby waves, volcano eruptions, tsunamis, mesoscale convective systems, and tropical cyclones. However, except for a few high-impact phenomena, e.g. tropical cyclones, comprehensive records are absent for the occurrences or events of these phenomena. Phenomenon-based studies therefore often focus on a few prominent cases while the lesser ones are overlooked. Without an automated means to gather the events, comprehensive investigation of a phenomenon is at least time-consuming if not impossible. We have constructed a prototype Automated Event Service (AES) system that is used to methodically mine custom-defined events in the reanalysis data sets of atmospheric general circulation models. Our AES will enable researchers to specify their custom, numeric event criteria using a user-friendly web interface to search the reanalysis data sets. Moreover, we have included a social component to enable dynamic formation of collaboration groups for researchers to cooperate on event definitions of common interest and for the analysis of these events. An Earth Science event (ES event) is defined here as an episode of an Earth Science phenomenon (ES phenomenon). A cumulus cloud, a thunderstorm shower, a rogue wave, a tornado, an earthquake, a tsunami, a hurricane, or an El Nino, is each an episode of a named ES phenomenon, and, from the small and insignificant to the large and potent, all are examples of ES events. An ES event has a duration (often finite) and an associated geo-location as a function of time; it's therefore an entity embedded in four-dimensional (4D) spatiotemporal space. Earth Science phenomena with the potential to cause massive economic disruption or loss of life often rivet the attention of researchers. But, broader scientific curiosity also drives the study of phenomena that pose no immediate danger, such as land/sea breezes. Due to Earth System

Spacecraft environmental interactions: A joint Air Force and NASA research and technology program

NASA Technical Reports Server (NTRS)

Pike, C. P.; Purvis, C. K.; Hudson, W. R.

1985-01-01

A joint Air Force/NASA comprehensive research and technology program on spacecraft environmental interactions to develop technology to control interactions between large spacecraft systems and the charged-particle environment of space is described. This technology will support NASA/Department of Defense operations of the shuttle/IUS, shuttle/Centaur, and the force application and surveillance and detection missions, planning for transatmospheric vehicles and the NASA space station, and the AFSC military space system technology model. The program consists of combined contractual and in-house efforts aimed at understanding spacecraft environmental interaction phenomena and relating results of ground-based tests to space conditions. A concerted effort is being made to identify project-related environmental interactions of concern. The basic properties of materials are being investigated to develop or modify the materials as needed. A group simulation investigation is evaluating basic plasma interaction phenomena to provide inputs to the analytical modeling investigation. Systems performance is being evaluated by both groundbased tests and analysis.

Switching Phenomena in a System with No Switches

NASA Astrophysics Data System (ADS)

Preis, Tobias; Stanley, H. Eugene

2010-02-01

It is widely believed that switching phenomena require switches, but this is actually not true. For an intriguing variety of switching phenomena in nature, the underlying complex system abruptly changes from one state to another in a highly discontinuous fashion. For example, financial market fluctuations are characterized by many abrupt switchings creating increasing trends ("bubble formation") and decreasing trends ("financial collapse"). Such switching occurs on time scales ranging from macroscopic bubbles persisting for hundreds of days to microscopic bubbles persisting only for a few seconds. We analyze a database containing 13,991,275 German DAX Future transactions recorded with a time resolution of 10 msec. For comparison, a database providing 2,592,531 of all S&P500 daily closing prices is used. We ask whether these ubiquitous switching phenomena have quantifiable features independent of the time horizon studied. We find striking scale-free behavior of the volatility after each switching occurs. We interpret our findings as being consistent with time-dependent collective behavior of financial market participants. We test the possible universality of our result by performing a parallel analysis of fluctuations in transaction volume and time intervals between trades. We show that these financial market switching processes have properties similar to those of phase transitions. We suggest that the well-known catastrophic bubbles that occur on large time scales—such as the most recent financial crisis—are no outliers but single dramatic representatives caused by the switching between upward and downward trends on time scales varying over nine orders of magnitude from very large (≈102 days) down to very small (≈10 ms).

Didactic Model--Bridging a Concept with Phenomena

ERIC Educational Resources Information Center

Shternberg, Beba; Yerushalmy, Michal

2004-01-01

The article focuses on a specific method of constructing the concept of function. The core of this method is a didactic model that plays two roles together--on the one hand a role of a model of the concept of function and on the other hand a role of a model of physical phenomena that functions can represent. This synergy of modeling situations and…

Coronal Mass Ejections (CMEs) and Associated Phenomena

NASA Astrophysics Data System (ADS)

Manoharan, P. K.

2008-10-01

The Sun is the most powerful radio waves emitting object in the sky. The first documented recognition of the reception of radio waves from the Sun was made in 1942 by Hey.15 Since then solar radio observations, from ground-based and space-based instruments, have played a major role in understanding the physics of the Sun and fundamental physical processes of the solar radio emitting phenomena...

Investigation of air pollution and regional climate change due to anthropogenic aerosols

NASA Astrophysics Data System (ADS)

Nakata, Makiko; Sano, Itaru; Mukai, Sonoyo

2016-10-01

Increased emissions of anthropogenic aerosols associated with economic growth can lead to increased concentrations of hazardous air pollutants. In particular, large cities in East Asia have experienced numerous heavy haze episodes. Atmospheric aerosol distributions in East Asia are complex, being influenced by both natural phenomena and human activity, with urban areas in particular being dominated by fine anthropogenic aerosols released from diesel-powered vehicles and industrial activity. In Japan, air pollution levels have been reduced; nevertheless, in recent years, there is increasing concern regarding air pollution caused by fine particulate matter. The origins of air pollution were examined, focusing on the comparison between aerosol properties observed from satellites and that on the ground. Because of their short life spans, concentrations of anthropogenic aerosols are highest over the source regions, and as a result, the climatic impacts of anthropogenic aerosols are also found to be most pronounced in these regions. In this study, aerosol impacts on climate are assessed by numerical model simulations. The direct effects of aerosols include reduced solar radiation, and hence a decrease in surface temperatures. In addition to these changes in the radiation budget, aerosols have a significant potential to change cloud and precipitation fields. These climatic responses to aerosols can manifest far from their source regions with high industrial activities.

Study on law of negative corona discharge in microparticle-air two-phase flow media

NASA Astrophysics Data System (ADS)

He, Bo; Li, Tianwei; Xiu, Yaping; Zhao, Heng; Peng, Zongren; Meng, Yongpeng

2016-03-01

To study the basic law of negative corona discharge in solid particle-air two-phase flow, corona discharge experiments in a needle-plate electrode system at different voltage levels and different wind speed were carried out in the wind tunnel. In this paper, the change law of average current and current waveform were analyzed, and the observed phenomena were systematically explained from the perspectives of airflow, particle charging, and particle motion with the help of PIV (particle image velocity) measurements and ultraviolet observations.

Modelling complex phenomena in optical fibres

NASA Astrophysics Data System (ADS)

Allington-Smith, Jeremy; Murray, Graham; Lemke, Ulrike

2012-09-01

We present a new model for predicting the performance of fibre systems in the multimode limit. This is based on ray-­-tracing but includes a semi-­-empirical description of Focal Ratio Degradation (FRD). We show how FRD is simulated by the model. With this ability, it can be used to investigate a wide variety of phenomena including scrambling and the loss of light close to the limiting numerical aperture. It can also be used to predict the performance of non-­-round and asymmetric fibres.

Investigation of Ozone Yield of Air Fed Ozonizer by High Pressure Homogeneous Dielectric Barrier Discharge

DTIC Science & Technology

2013-07-01

31st ICPIG, July 14-19, 2013, Granada , Spain Investigation of ozone yield of air fed ozonizer by high pressure homogeneous dielectric barrier...Phenomena in Ionized Gases (31st) (ICPIG) Held in Granada , Spain on 14-19 July 2013 14. ABSTRACT We succeed in generating an atmospheric and high...8-98) Prescribed by ANSI Std Z39-18 31st ICPIG, July 14-19, 2013, Granada , Spain size and thickness are 100 cm2 and 2 mm respectively. The

Urban political ecologies of informal recyclers׳ health in Buenos Aires, Argentina.

PubMed

Parizeau, Kate

2015-05-01

Buenos Aires׳ informal recyclers (cartoneros) confront multiple health hazards in their work. Based in a survey with (n=397) informal recyclers, this study establishes that these workers experience uneven health landscapes as evidenced through their health outcomes, the social determinants of their health, and their living and working environments. I argue that the analytical framework of urban political ecology can provide insights to the ways that the urban environments where cartoneros live and work are socially-constructed phenomena, drawing on concepts of crisis, metabolism, and multi-scalar analyses. Copyright © 2015 Elsevier Ltd. All rights reserved.

INVESTIGATIONS INTO BIOFOULING PHENOMENA IN FINE PORE AERATION DEVICES

EPA Science Inventory

Microbiologically-based procedures were used to describe biofouling phenomena on fine pore aeration devices and to determine whether biofilm characteristics could be related to diffuser process performance parameters. Fine pore diffusers were obtained from five municipal wastewa...

Association between lower air pressure and the onset of ischemic colitis: a case-control study.

PubMed

Kimura, Takefumi; Shinji, Akihiro; Tanaka, Naoki; Koinuma, Masayoshi; Yamaura, Maki; Nagaya, Tadanobu; Joshita, Satoru; Komatsu, Michiharu; Umemura, Takeji; Horiuchi, Akira; Wada, Shuichi; Tanaka, Eiji

2017-09-01

Ischemic colitis (IC) often affects the elderly. Proarteriosclerotic factors, such as hypertension and smoking, and cardiovascular disease are considered major contributors to IC. Although a possible link between certain cerebrocardiovascular disorders and meteorological phenomena has been reported, the relationship between IC onset and weather changes remains uninvestigated. This study examined whether specific meteorological factors were associated with the occurrence of IC. We retrospectively enrolled 303 patients who had been diagnosed with IC between January 2003 and June 2010 at Suwa Red Cross Hospital in Nagano Prefecture, Japan. The meteorological data of the days on which IC patients visited the hospital (IC+ days) were compared with those of the days on which IC patients did not (IC- days). Univariate analysis indicated that IC+ days had significantly lower air pressure (P<0.001), depressed air pressure from the previous day (P<0.001), and fewer daylight hours (P<0.001), as well as higher air temperature (P=0.017), air humidity (P=0.004), wind velocity (P<0.001), and rainfall (P=0.012) compared with IC- days. Multivariate logistic regression analysis of the meteorological data showed that air pressure (odds ratio: 0.935, P<0.001) and change in air pressure from the previous day (odds ratio: 0.934, P<0.001) were related to onset of IC. Lower air pressure and decrease in air pressure from the previous day are possible novel factors associated with the development of IC.

Integrated Mission Precision Attack Cockpit Technology (IMPACT). Phase 1: Identifying Technologies for Air-to-Ground Fighter Integration.

DTIC Science & Technology

1994-10-31

No comment S4: No comment 63 3. The HMD would my...released (i.e., not hung) without looking down on the PACS page is very good." S4: No comment 6. The HMD would my SITUATIONAL AWARENESS during the INGRESS...Substantially Degrade 0 (Subject 1: NO RATING) HOW? S 1: No comment S2: "Previous reasons, visibility REF # 2, 4" S3: No comment S4: No comment 65 7. The

Risk in nuclear power plants due to natural hazard phenomena

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

Lu, S.C.

1995-12-01

For the safety of nuclear power plants, it is important to identify potential areas of vulnerabilities to internal as well as external events to which nuclear power plants are exposed. This paper summarizes the risk in nuclear power plants due to natural hazard phenomena such as earthquakes, winds and tornadoes, floods, etc. The reported results are based on a limited number of probabilistic risk assessments (PRAS) performed for a few of the operating nuclear power plants within the United States. The summary includes an importance ranking of various natural hazard phenomena based on their contribution to the plant risk alongmore » with insights observed from the PRA studies.« less

Mesoscopic modeling of multi-physicochemical transport phenomena in porous media

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

Kang, Qinjin; Wang, Moran; Mukherjee, Partha P

2009-01-01

We present our recent progress on mesoscopic modeling of multi-physicochemical transport phenomena in porous media based on the lattice Boltzmann method. Simulation examples include injection of CO{sub 2} saturated brine into a limestone rock, two-phase behavior and flooding phenomena in polymer electrolyte fuel cells, and electroosmosis in homogeneously charged porous media. It is shown that the lattice Boltzmann method can account for multiple, coupled physicochemical processes in these systems and can shed some light on the underlying physics occuning at the fundamental scale. Therefore, it can be a potential powerful numerical tool to analyze multi-physicochemical processes in various energy, earth,more » and environmental systems.« less

An assessment of Gallistel's (2012) rationalistic account of extinction phenomena.

PubMed

Miller, Ralph R

2012-05-01

Gallistel (2012) asserts that animals use rationalistic reasoning (i.e., information theory and Bayesian inference) to make decisions that underlie select extinction phenomena. Rational processes are presumed to lead to evolutionarily optimal behavior. Thus, Gallistel's model is a type of optimality theory. But optimality theory is only a theory, a theory about an ideal organism, and its predictions frequently deviate appreciably from observed behavior of animals in the laboratory and the real world. That is, behavior of animals is often far from optimal, as is evident in many behavioral phenomena. Hence, appeals to optimality theory to explain, rather than illuminate, actual behavior are misguided. Copyright © 2012 Elsevier B.V. All rights reserved.

Interplay of Internal and External Representations: Students' Drawings and Textual Explanations about Shadow Phenomena

ERIC Educational Resources Information Center

Valanides, Nicos; Efthymiou, Irene; Angeli, Charoula

2013-01-01

Fifty-six third-year kindergarten student teachers (KTS) were presented with an experimental setting for investigating shadow phenomena. Prior to performing any specific experiment, KTS were asked to externalize their ideas about shadow phenomena corresponding to different configurations of the experimental setting through the use of drawings…

Laboratory simulation of space plasma phenomena*

NASA Astrophysics Data System (ADS)

Amatucci, B.; Tejero, E. M.; Ganguli, G.; Blackwell, D.; Enloe, C. L.; Gillman, E.; Walker, D.; Gatling, G.

2017-12-01

Laboratory devices, such as the Naval Research Laboratory's Space Physics Simulation Chamber, are large-scale experiments dedicated to the creation of large-volume plasmas with parameters realistically scaled to those found in various regions of the near-Earth space plasma environment. Such devices make valuable contributions to the understanding of space plasmas by investigating phenomena under carefully controlled, reproducible conditions, allowing for the validation of theoretical models being applied to space data. By working in collaboration with in situ experimentalists to create realistic conditions scaled to those found during the observations of interest, the microphysics responsible for the observed events can be investigated in detail not possible in space. To date, numerous investigations of phenomena such as plasma waves, wave-particle interactions, and particle energization have been successfully performed in the laboratory. In addition to investigations such as plasma wave and instability studies, the laboratory devices can also make valuable contributions to the development and testing of space plasma diagnostics. One example is the plasma impedance probe developed at NRL. Originally developed as a laboratory diagnostic, the sensor has now been flown on a sounding rocket, is included on a CubeSat experiment, and will be included on the DoD Space Test Program's STP-H6 experiment on the International Space Station. In this presentation, we will describe several examples of the laboratory investigation of space plasma waves and instabilities and diagnostic development. *This work supported by the NRL Base Program.

Modeling of convection phenomena in Bridgman-Stockbarger crystal growth

NASA Technical Reports Server (NTRS)

Carlson, F. M.; Eraslan, A. H.; Sheu, J. Z.

1985-01-01

Thermal convection phenomena in a vertically oriented Bridgman-Stockbarger apparatus were modeled by computer simulations for different gravity conditions, ranging from earth conditions to extremely low gravity, approximate space conditions. The modeling results were obtained by the application of a state-of-the art, transient, multi-dimensional, completely densimetrically coupled, discrete-element computational model which was specifically developed for the simulation of flow, temperature, and species concentration conditions in two-phase (solid-liquid) systems. The computational model was applied to the simulation of the flow and the thermal conditions associated with the convection phenomena in a modified Germanium-Silicon charge enclosed in a stationary fused-silica ampoule. The results clearly indicated that the gravitational field strength influences the characteristics of the coherent vortical flow patterns, interface shape and position, maximum melt velocity, and interfacial normal temperature gradient.

[Is the brain the creator of psychic phenomena or is a paradigm shift inevitable?].

PubMed

Bonilla, Ernesto

2014-06-01

Every day new scientific information is appearing that cannot be explained using the classical Newtonian model and is calling for the emergence of a new paradigm that would include the explanation of such phenomena as telepathy, clairvoyance, presentiment, precognition, out of the body experiences, psychic healing, after-death communication, near-death experiences and reincarnation. The materialist paradigm which considers the brain as the sole cause of consciousness and psychic phenomena has been challenged by a new paradigm that seems to demonstrate that there is not a cause-effect relationship between brain activity and psychic phenomena but only a correlation between them, since these phenomena can be experienced without the body and appear to have an extra-cerebral origin (cosmic field, cosmic consciousness?). Of course, the brain is intensely involved in the manifestation of consciousness in our daily life but this is not equivalent to affirm that brain creates consciousness. Recent findings force us to consider a non-physical, spiritual and transpersonal aspect of reality.

The Impact of the Qur'anic Conception of Astronomical Phenomena on Islamic Civilization

NASA Astrophysics Data System (ADS)

Ahmad, I. A.

Discussions of astronomical phenomena in religious texts usually center around either their literal astronomical content or their symbolic significance. We shall instead consider the use of frequent references to astronomical phenomena in the Qur'an as exhortations to a worldview that ushered in the modern era. The Qur'anic conception of astronomical phenomena had a critical impact on Islamic civilization and the civilizations that followed because it introduced and mandated the adoption of certain attitudes. Among these were a greater respect for empirical data than was common in the preceding Greek civilization and an insistence that the Universe is ruled by a single set of laws. Both of these were rooted in the Islamic concept of tawhîd, the unity of God.

To investigate or not to investigate? Researchers' views on unexplored atmospheric light phenomena

NASA Astrophysics Data System (ADS)

Caron, Etienne; Faridi, Pouya

2016-02-01

For hundreds of years, scientists have been studying light, which is used nowadays to explore the universe and cure diseases. Here, we present the results of a survey indicating a significant support from a subset of the academic community to investigate rare, unusual and unexplained atmospheric light phenomena that have historically been unexplored by scientists — the transient luminous phenomena in the valley of Hessdalen in Norway in particular. We propose that stable, long-term funding, and thorough investigation of poorly understood and/or unexplored luminous phenomena occurring in the low atmosphere could lead to the creation of new inter-disciplinary research programs in multiple universities, and ultimately, to important fundamental discoveries in the field of atmospheric science, photonics and beyond.

A numerical solution of Duffing's equations including the prediction of jump phenomena

NASA Technical Reports Server (NTRS)

Moyer, E. T., Jr.; Ghasghai-Abdi, E.

1987-01-01

Numerical methodology for the solution of Duffing's differential equation is presented. Algorithms for the prediction of multiple equilibrium solutions and jump phenomena are developed. In addition, a filtering algorithm for producing steady state solutions is presented. The problem of a rigidly clamped circular plate subjected to cosinusoidal pressure loading is solved using the developed algorithms (the plate is assumed to be in the geometrically nonlinear range). The results accurately predict regions of solution multiplicity and jump phenomena.

Robert Boyle's landmark book of 1660 with the first experiments on rarified air.

PubMed

West, John B

2005-01-01

In 1660, Robert Boyle (1627-1691) published his landmark book New Experiments Physico-Mechanicall, Touching the Spring of the Air, and its Effects... in which he described the first controlled experiments of the effects of reducing the pressure of the air. Critical to this work was the development of an air pump by Boyle with Robert Hooke (1635-1703). For the first time, it was possible to observe physical and physiological processes at both normal and reduced barometric pressures. The air pump was described in detail, although the exact design of the critical piston is unclear. Boyle reported 43 separate experiments, which can conveniently be divided into 7 groups. The first experiments were on the "spring of the air," that is the pressure developed by the air when its volume was changed. Several experiments described the behavior of the barometer invented by Torricelli just 16 years before when it was introduced into the low-pressure chamber. The behavior of burning candles was discussed, although this emphasized early misunderstandings of the nature of combustion. There were some physiological observations, although these were later extended by Boyle and Hooke. The effects of the low pressure on such diverse physical phenomena as magnetism, sound propagation, behavior of a pendulum, evolution of gases from liquids, and the behavior of smoke were described. This classic book is brimming with enthusiasm and fresh ideas even for today and deserves to be better known.

Superfluous neuroscience information makes explanations of psychological phenomena more appealing.

PubMed

Fernandez-Duque, Diego; Evans, Jessica; Christian, Colton; Hodges, Sara D

2015-05-01

Does the presence of irrelevant neuroscience information make explanations of psychological phenomena more appealing? Do fMRI pictures further increase that allure? To help answer these questions, 385 college students in four experiments read brief descriptions of psychological phenomena, each one accompanied by an explanation of varying quality (good vs. circular) and followed by superfluous information of various types. Ancillary measures assessed participants' analytical thinking, beliefs on dualism and free will, and admiration for different sciences. In Experiment 1, superfluous neuroscience information increased the judged quality of the argument for both good and bad explanations, whereas accompanying fMRI pictures had no impact above and beyond the neuroscience text, suggesting a bias that is conceptual rather than pictorial. Superfluous neuroscience information was more alluring than social science information (Experiment 2) and more alluring than information from prestigious "hard sciences" (Experiments 3 and 4). Analytical thinking did not protect against the neuroscience bias, nor did a belief in dualism or free will. We conclude that the "allure of neuroscience" bias is conceptual, specific to neuroscience, and not easily accounted for by the prestige of the discipline. It may stem from the lay belief that the brain is the best explanans for mental phenomena.

A Bayesian explanation of the "Uncanny Valley" effect and related psychological phenomena

NASA Astrophysics Data System (ADS)

Moore, Roger K.

2012-11-01

There are a number of psychological phenomena in which dramatic emotional responses are evoked by seemingly innocuous perceptual stimuli. A well known example is the `uncanny valley' effect whereby a near human-looking artifact can trigger feelings of eeriness and repulsion. Although such phenomena are reasonably well documented, there is no quantitative explanation for the findings and no mathematical model that is capable of predicting such behavior. Here I show (using a Bayesian model of categorical perception) that differential perceptual distortion arising from stimuli containing conflicting cues can give rise to a perceptual tension at category boundaries that could account for these phenomena. The model is not only the first quantitative explanation of the uncanny valley effect, but it may also provide a mathematical explanation for a range of social situations in which conflicting cues give rise to negative, fearful or even violent reactions.

Natural phenomena hazards design and evaluation criteria for Department of Energy Facilities

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

NONE

1996-01-01

The Department of Energy (DOE) has issued an Order 420.1 which establishes policy for its facilities in the event of natural phenomena hazards (NPH) along with associated NPH mitigation requirements. This DOE Standard gives design and evaluation criteria for NPH effects as guidance for implementing the NPH mitigation requirements of DOE Order 420.1 and the associated implementation Guides. These are intended to be consistent design and evaluation criteria for protection against natural phenomena hazards at DOE sites throughout the United States. The goal of these criteria is to assure that DOE facilities can withstand the effects of natural phenomena suchmore » as earthquakes, extreme winds, tornadoes, and flooding. These criteria apply to the design of new facilities and the evaluation of existing facilities. They may also be used for modification and upgrading of existing facilities as appropriate. The design and evaluation criteria presented herein control the level of conservatism introduced in the design/evaluation process such that earthquake, wind, and flood hazards are treated on a consistent basis. These criteria also employ a graded approach to ensure that the level of conservatism and rigor in design/evaluation is appropriate for facility characteristics such as importance, hazards to people on and off site, and threat to the environment. For each natural phenomena hazard covered, these criteria consist of the following: Performance Categories and target performance goals as specified in the DOE Order 420.1 NPH Implementation Guide, and DOE-STD-1 021; specified probability levels from which natural phenomena hazard loading on structures, equipment, and systems is developed; and design and evaluation procedures to evaluate response to NPH loads and criteria to assess whether or not computed response is permissible.« less

Layered phenomena in the mesopause region

NASA Astrophysics Data System (ADS)

Plane, J. M. C.; Bailey, S. M.; Baumgarten, G.; Rapp, M.

2015-05-01

This special issue of the Journal of Atmospheric and Solar-Terrestrial Physics comprises a collection of papers which were mostly presented at the 11th Layered Phenomena in the Mesopause Region (LPMR) Workshop, held at the University of Leeds between 29th July 2013 and 1st August 2013. The topics covered at the workshop included atmospheric dynamics, mesospheric ice clouds, meteoric metal layers, meteoric smoke particles, and airglow layers. There was also a session on the potential of planned sub-orbital spacecraft for making measurements in the mesosphere and lower thermosphere (MLT).

Modelling transport phenomena in a multi-physics context

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

Marra, Francesco

2015-01-22

Innovative heating research on cooking, pasteurization/sterilization, defrosting, thawing and drying, often focuses on areas which include the assessment of processing time, evaluation of heating uniformity, studying the impact on quality attributes of the final product as well as considering the energy efficiency of these heating processes. During the last twenty years, so-called electro-heating-processes (radio-frequency - RF, microwaves - MW and ohmic - OH) gained a wide interest in industrial food processing and many applications using the above mentioned technologies have been developed with the aim of reducing processing time, improving process efficiency and, in many cases, the heating uniformity. Inmore » the area of innovative heating, electro-heating accounts for a considerable portion of both the scientific literature and commercial applications, which can be subdivided into either direct electro-heating (as in the case of OH heating) where electrical current is applied directly to the food or indirect electro-heating (e.g. MW and RF heating) where the electrical energy is firstly converted to electromagnetic radiation which subsequently generates heat within a product. New software packages, which make easier solution of PDEs based mathematical models, and new computers, capable of larger RAM and more efficient CPU performances, allowed an increasing interest about modelling transport phenomena in systems and processes - as the ones encountered in food processing - that can be complex in terms of geometry, composition, boundary conditions but also - as in the case of electro-heating assisted applications - in terms of interaction with other physical phenomena such as displacement of electric or magnetic field. This paper deals with the description of approaches used in modelling transport phenomena in a multi-physics context such as RF, MW and OH assisted heating.« less

Modelling transport phenomena in a multi-physics context

NASA Astrophysics Data System (ADS)

Marra, Francesco

2015-01-01

Innovative heating research on cooking, pasteurization/sterilization, defrosting, thawing and drying, often focuses on areas which include the assessment of processing time, evaluation of heating uniformity, studying the impact on quality attributes of the final product as well as considering the energy efficiency of these heating processes. During the last twenty years, so-called electro-heating-processes (radio-frequency - RF, microwaves - MW and ohmic - OH) gained a wide interest in industrial food processing and many applications using the above mentioned technologies have been developed with the aim of reducing processing time, improving process efficiency and, in many cases, the heating uniformity. In the area of innovative heating, electro-heating accounts for a considerable portion of both the scientific literature and commercial applications, which can be subdivided into either direct electro-heating (as in the case of OH heating) where electrical current is applied directly to the food or indirect electro-heating (e.g. MW and RF heating) where the electrical energy is firstly converted to electromagnetic radiation which subsequently generates heat within a product. New software packages, which make easier solution of PDEs based mathematical models, and new computers, capable of larger RAM and more efficient CPU performances, allowed an increasing interest about modelling transport phenomena in systems and processes - as the ones encountered in food processing - that can be complex in terms of geometry, composition, boundary conditions but also - as in the case of electro-heating assisted applications - in terms of interaction with other physical phenomena such as displacement of electric or magnetic field. This paper deals with the description of approaches used in modelling transport phenomena in a multi-physics context such as RF, MW and OH assisted heating.

Deriving Case, Agreement and Voice Phenomena in Syntax

ERIC Educational Resources Information Center

Sigurdsson, Einar Freyr

2017-01-01

This dissertation places case, agreement and Voice phenomena in syntax. It argues that the derivation is driven by so-called derivational features, that is, structure-building features (Merge) and probe features (Agree) (Heck and Muller 2007 and Muller 2010; see also Chomsky 2000, 2001). Both types are essential in deriving case and agreement in…

Nuclear phenomena in low-energy nuclear reaction research.

PubMed

Krivit, Steven B

2013-09-01

This is a comment on Storms E (2010) Status of Cold Fusion, Naturwissenschaften 97:861-881. This comment provides the following remarks to other nuclear phenomena observed in low-energy nuclear reactions aside from helium-4 make significant contributions to the overall energy balance; and normal hydrogen, not just heavy hydrogen, produces excess heat.

Lean limit phenomena

NASA Technical Reports Server (NTRS)

Law, C. K.

1984-01-01

The concept of flammability limits in the presence of flame interaction, and the existence of negative flame speeds are discussed. Downstream interaction between two counterflow premixed flames of different stoichiometries are experimentally studied. Various flame configurations are observed and quantified; these include the binary system of two lean or rich flames, the triplet system of a lean and a rich flame separated by a diffusion flame, and single diffusion flames with some degree of premixedness. Extinction limits are determined for methane/air and butane/air mixtures over the entire range of mixture concentrations. The results show that the extent of flame interaction depends on the separation distance between the flames which are functions of the mixtures' concentrations, the stretch rate, and the effective Lewis numbers (Le). In particular, in a positively-stretched flow field Le 1 ( 1) mixtures tend to interact strongly (weakly), while the converse holds for flames in a negatively-stretched flow. Also established was the existence of negative flames whose propagation velocity is in the same general direction as that of the bulk convective flow, being supported by diffusion alone. Their existence demonstrates the tendency of flames to resist extinction, and further emphasizes the possibility of very lean or rich mixtures to undergo combustion.

Augmented Visual Experience of Simulated Solar Phenomena

NASA Astrophysics Data System (ADS)

Tucker, A. O., IV; Berardino, R. A.; Hahne, D.; Schreurs, B.; Fox, N. J.; Raouafi, N.

2017-12-01

The Parker Solar Probe (PSP) mission will explore the Sun's corona, studying solar wind, flares and coronal mass ejections. The effects of these phenomena can impact the technology that we use in ways that are not readily apparent, including affecting satellite communications and power grids. Determining the structure and dynamics of corona magnetic fields, tracing the flow of energy that heats the corona, and exploring dusty plasma near the Sun to understand its influence on solar wind and energetic particle formation requires a suite of sensors on board the PSP spacecraft that are engineered to observe specific phenomena. Using models of these sensors and simulated observational data, we can visualize what the PSP spacecraft will "see" during its multiple passes around the Sun. Augmented reality (AR) technologies enable convenient user access to massive data sets. We are developing an application that allows users to experience environmental data from the point of view of the PSP spacecraft in AR using the Microsoft HoloLens. Observational data, including imagery, magnetism, temperature, and density are visualized in 4D within the user's immediate environment. Our application provides an educational tool for comprehending the complex relationships of observational data, which aids in our understanding of the Sun.

Emergent ultrafast phenomena in correlated oxides and heterostructures

NASA Astrophysics Data System (ADS)

Gandolfi, M.; Celardo, G. L.; Borgonovi, F.; Ferrini, G.; Avella, A.; Banfi, F.; Giannetti, C.

2017-03-01

The possibility of investigating the dynamics of solids on timescales faster than the thermalization of the internal degrees of freedom has disclosed novel non-equilibrium phenomena that have no counterpart at equilibrium. Transition metal oxides (TMOs) provide an interesting playground in which the correlations among the charges in the metal d-orbitals give rise to a wealth of intriguing electronic and thermodynamic properties involving the spin, charge, lattice and orbital orders. Furthermore, the physical properties of TMOs can be engineered at the atomic level, thus providing the platform to investigate the transport phenomena on timescales of the order of the intrinsic decoherence time of the charge excitations. Here, we review and discuss three paradigmatic examples of transient emerging properties that are expected to open new fields of research: (i) the creation of non-thermal magnetic states in spin-orbit Mott insulators; (ii) the possible exploitation of quantum paths for the transport and collection of charge excitations in heterostructures; (iii) the transient wave-like behavior of the temperature field in strongly anisotropic TMOs.

EDITORIAL: Quantum phenomena in Nanotechnology Quantum phenomena in Nanotechnology

NASA Astrophysics Data System (ADS)

Loss, Daniel

2009-10-01

Twenty years ago the Institute of Physics launched the journal Nanotechnology from its publishing house based in the home town of Paul Dirac, a legendary figure in the development of quantum mechanics at the turn of the last century. At the beginning of the 20th century, the adoption of quantum mechanical descriptions of events transformed the existing deterministic world view. But in many ways it also revolutionised the progress of research itself. For the first time since the 17th century when Francis Bacon established inductive reasoning as the means of advancing science from fact to axiom to law, theory was progressing ahead of experiments instead of providing explanations for observations that had already been made. Dirac's postulation of antimatter through purely theoretical investigation before its observation is the archetypal example of theory leading the way for experiment. The progress of nanotechnology and the development of tools and techniques that enabled the investigation of systems at the nanoscale brought with them many fascinating observations of phenomena that could only be explained through quantum mechanics, first theoretically deduced decades previously. At the nanoscale, quantum confinement effects dominate the electrical and optical properties of systems. They also render new opportunities for manipulating the response of systems. For example, a better understanding of these systems has enabled the rapid development of quantum dots with precisely determined properties, which can be exploited in a range of applications from medical imaging and photovoltaic solar cells to quantum computation, a radically new information technology being currently developed in many labs worldwide. As the first ever academic journal in nanotechnology, {\\it Nanotechnology} has been the forum for papers detailing progress of the science through extremely exciting times. In the early years of the journal, the investigation of electron spin led to the formulation

Novel Method for Detection of Air Pollution using Cellular Communication Networks

NASA Astrophysics Data System (ADS)

David, N.; Gao, O. H.

2016-12-01

Air pollution can lead to a wide spectrum of severe and chronic health impacts. Conventional tools for monitoring the phenomenon do not provide a sufficient monitoring solution in a global scale since they are, for example, not representative of the larger space or due to limited deployment as a result of practical limitations, such as: acquisition, installation, and ongoing maintenance costs. Near ground temperature inversions are directly identified with air pollution events since they suppress vertical atmospheric movement and trap pollutants near the ground. Wireless telecommunication links that comprise the data transfer infrastructure in cellular communication networks operate at frequencies of tens of GHz and are affected by different atmospheric phenomena. These systems are deployed near ground level across the globe, including in developing countries such as India, countries in Africa, etc. Many cellular providers routinely store data regarding the received signal levels in the network for quality assurance needs. Temperature inversions cause atmospheric layering, and change the refractive index of the air when compared to standard conditions. As a result, the ducts that are formed can operate, in essence, as atmospheric wave guides, and cause interference (signal amplification / attenuation) in the microwaves measured by the wireless network. Thus, this network is in effect, an existing system of environmental sensors for monitoring temperature inversions and the episodes of air pollution identified with them. This work presents the novel idea, and demonstrates it, in operation, over several events of air pollution which were detected by a standard cellular communication network during routine operation. Reference: David, N. and Gao, H.O. Using cellular communication networks to detect air pollution, Environmental Science & Technology, 2016 (accepted).

Thermal-Hydraulics Phenomena Important in Modeling and Simulation of Liquid-Fuel Molten Salt Reactors

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

Bajorek, Stephen; Diamond, David J.

This paper discusses liquid-fuel molten salt reactors, how they will operate under normal, transient, and accident conditions, and the results of an expert elicitation to determine the corresponding thermalhydraulic phenomena important to understanding their behavior. Identifying these phenomena will enable the U.S. Nuclear Regulatory Commission (NRC) to develop or identify modeling functionalities and tools required to carry out confirmatory analyses that examine the validity and accuracy of an applicant’s calculations and help determine the margin of safety in plant design. NRC frequently does an expert elicitation using a Phenomena Identification and Ranking Table (PIRT) to identify and evaluate the statemore » of knowledge of important modeling phenomena. However, few details about the design of these reactors and the sequence of events during accidents are known, so the process used was considered a preliminary PIRT. A panel met to define phenomena that would need to be modeled and considered the impact/importance of each phenomenon with respect to specific figures-of-merit (FoMs) (e.g., salt temperature, velocity, and composition). Each FoM reflected a potential impact on radionuclide release or loss of a barrier to release. The panel considered what the path forward might be with respect to being able to model the phenomenon in a simulation code. Results are explained for both thermal and fast spectrum designs.« less

A new multiscale air quality transport model (Fluidity, 4.1.9) using fully unstructured anisotropic adaptive mesh technology

NASA Astrophysics Data System (ADS)

Zheng, J.; Zhu, J.; Wang, Z.; Fang, F.; Pain, C. C.; Xiang, J.

2015-06-01

A new anisotropic hr-adaptive mesh technique has been applied to modelling of multiscale transport phenomena, which is based on a discontinuous Galerkin/control volume discretization on unstructured meshes. Over existing air quality models typically based on static-structured grids using a locally nesting technique, the advantage of the anisotropic hr-adaptive model has the ability to adapt the mesh according to the evolving pollutant distribution and flow features. That is, the mesh resolution can be adjusted dynamically to simulate the pollutant transport process accurately and effectively. To illustrate the capability of the anisotropic adaptive unstructured mesh model, three benchmark numerical experiments have been setup for two-dimensional (2-D) transport phenomena. Comparisons have been made between the results obtained using uniform resolution meshes and anisotropic adaptive resolution meshes.

Acoustic phenomena observed in lung auscultation

NASA Astrophysics Data System (ADS)

Korenbaum, V. I.; Tagil'Tsev, A. A.; Kulakov, Yu. V.

2003-05-01

The results of studying respiratory noise at the chest wall by the method of acoustic intensimetry reveal the presence of frequency components with different signs of the real and imaginary parts of the cross spectrum obtained for the responses of the receivers of vibratory displacement and dynamic force. An acoustic model is proposed to explain this difference on the basis of the hypothesis that the contributions of both air-borne and structure-borne sound are significant in the transmission of respiratory noise to the chest wall. It is shown that, when considered as an acoustic channel for the basic respiratory noise, the respiratory system of an adult subject has two resonances: in the frequency bands within 110 150 and 215 350 Hz. For adults in normal condition, the air-borne component of the basic respiratory noise predominates in the region 100 300 Hz in the lower parts of lungs. At forced respiration of healthy adults, the sounds of vesicular respiration are generated by the turbulent air flow in the 11th-through 13th-generation bronchi, and the transmission of these sounds to the chest wall in normal condition is mainly through air and is determined by the resonance of the vibratory system formed by the elasticity of air in the respiratory ducts of lungs and by the surface mass density of the chest wall. It is demonstrated that the distance from the chest wall to the sources of structure-borne additional respiratory noise, namely, wheezing with frequencies above 300 Hz, can be estimated numerically from the ratio between the real and imaginary parts of the cross spectrum on the assumption that the source is of the quadrupole type.

Slow slip phenomena in Cascadia from 2007 and beyond: a review

USGS Publications Warehouse

Gomberg, Joan; ,

2010-01-01

Recent technological advances combined with more detailed analyses of seismologic and geodetic observations have fundamentally changed our understanding of the ways in which tectonic stresses arising from plate motions are accommodated by slip on faults. The traditional view that relative plate motions are accommodated by a simple cycle of stress accumulation and release on “locked” plate-boundary faults has been revolutionized by the serendipitous discovery and recognition of the significance of slow-slip phenomena, mostly in the deeper reaches of subduction zones. The Cascadia subduction zone, located in the Pacific Northwest of the conterminous United States and adjacent Canada, is an archetype of exploration and learning about slow-slip phenomena. These phenomena are manifest as geodetically observed aseismic transient deformations accompanied by a previously unrecognized class of seismic signals. Although secondary failure processes may be involved in generating the seismic signals, the primary origins of both aseismic and seismic phenomena appear to be episodic fault slip, probably facilitated by fluids, on a plate interface that is critically stressed or weakened. In Cascadia, this transient slip evolves more slowly and over more prolonged durations relative to the slip in earthquakes, and it occurs between the 30- and 40-km-depth contours of the plate interface where information was previously elusive. Although there is some underlying organization that relaxes nearly all the accrued plate-motion stresses along the entirety of Cascadia, we now infer that slow slip evolves in complex patterns indicative of propagating stress fronts. Our new understanding provides key constraints not only on the region where the slow slip originates, but also on the probable characteristics of future megathrust earthquakes in Cascadia. Herein, we review the most significant scientific issues and progress related to understanding slow-slip phenomena in Cascadia and

Characteristics of a Direct Current-driven plasma jet operated in open air

NASA Astrophysics Data System (ADS)

Li, Xuechen; Di, Cong; Jia, Pengying; Bao, Wenting

2013-09-01

A DC-driven plasma jet has been developed to generate a diffuse plasma plume by blowing argon into the ambient air. The plasma plume, showing a cup shape with a diameter of several centimeters at a higher voltage, is a pulsed discharge despite a DC voltage is applied. The pulse frequency is investigated as a function of the voltage under different gap widths and gas flow rates. Results show that plasma bullets propagate from the hollow needle to the plate electrode by spatially resolved measurement. A supposition about non-electroneutral trail of the streamer is proposed to interpret these experimental phenomena.

An Initial Investigation of the Psychedelic Drug Flashback Phenomena

ERIC Educational Resources Information Center

Matefy, Robert E.; Krall, Roger G.

1974-01-01

This study investigated some characteristics of persons experiencing "flashbacks," and provides systematic descriptions of the flashback phenomena. The drug user showed no significant differences in psychopathological characteristics as measured by the MMPI, nor significant differences in attentional processes as measured by the Embedded Figures…

Consensus on core phenomena and statements describing Basic Body Awareness Therapy within the movement awareness domain in physiotherapy.

PubMed

Skjaerven, L H; Mattsson, M; Catalan-Matamoros, D; Parker, A; Gard, G; Gyllensten, A Lundvik

2018-02-26

Physiotherapists are facing complex health challenges in the treatment of persons suffering from long-lasting musculoskeletal disorders and mental health problems. Basic Body Awareness Therapy (BBAT) is a physiotherapy approach within the movement awareness domain developed to bridge physical, mental, and relational health challenges. The purpose of this study was to reach a consensus on core phenomena and statements describing BBAT. A consensus-building process was conducted using the nominal group technique (NGT). Twenty-one BBAT experts from 10 European countries participated in a concentrated weekend workshop of 20 hours. All participants signed informed consent. Participants reached a consensus on 138 core phenomena, clustered in three overarching categories: clinical core, historical roots, and research and evaluation phenomena. Of the 106 clinical core phenomena, the participants agreed on three categories of phenomena: movement quality, movement awareness practice, and movement awareness therapy and pedagogy. Furthermore, the participants reached 100 percent consensus on 16 of 30 statements describing BBAT. This study provides a consensus on core phenomena and statements describing BBAT. The data reveal phenomena implemented when promoting movement quality through movement awareness. Data provide clarity in some aspects of the vocabulary as fundamental theory. Further reearch will be developed.

Replication Unreliability in Psychology: Elusive Phenomena or “Elusive” Statistical Power?

PubMed Central

Tressoldi, Patrizio E.

2012-01-01

The focus of this paper is to analyze whether the unreliability of results related to certain controversial psychological phenomena may be a consequence of their low statistical power. Applying the Null Hypothesis Statistical Testing (NHST), still the widest used statistical approach, unreliability derives from the failure to refute the null hypothesis, in particular when exact or quasi-exact replications of experiments are carried out. Taking as example the results of meta-analyses related to four different controversial phenomena, subliminal semantic priming, incubation effect for problem solving, unconscious thought theory, and non-local perception, it was found that, except for semantic priming on categorization, the statistical power to detect the expected effect size (ES) of the typical study, is low or very low. The low power in most studies undermines the use of NHST to study phenomena with moderate or low ESs. We conclude by providing some suggestions on how to increase the statistical power or use different statistical approaches to help discriminate whether the results obtained may or may not be used to support or to refute the reality of a phenomenon with small ES. PMID:22783215

Effects of Social Psychological Phenomena on School Psychologists' Ethical Decision-Making: A Preliminary Empirical Analysis

ERIC Educational Resources Information Center

Klose, Laurie McGarry; Lasser, Jon; Reardon, Robert F.

2012-01-01

This preliminary, exploratory study examines the impact of select social psychological phenomena on school-based ethical decision-making of school psychologists. Responses to vignettes and hypothetical statements reflecting several social psychological phenomena were collected from 106 practicing school psychologists. Participants were asked to…

[Investigations of psychic/spiritual phenomena in the nineteenth century: somnambulism and spiritualism, 1811-1860].

PubMed

Pimentel, Marcelo Gulão; Alberto, Klaus Chaves; Moreira-Almeida, Alexander

2016-01-01

In the early nineteenth century, investigations into the nature of psychic/spiritual phenomena, like trances and the supposed acquisition of information unattainable using normal sensory channels, prompted much debate in the scientific arena. This article discusses the main explanations offered by the researchers of psychic phenomena reported between 1811 and 1860, concentrating on the two main movements in the period: magnetic somnambulism and modern spiritualism. While the investigations of these phenomena gave rise to multiple theories, they did not yield any consensus. However, they did have implications for the understanding of the mind and its disorders, especially in the areas of the unconscious and dissociation, constituting an important part of the history of psychology and psychiatry.

Proceedings of the Fourth Microgravity Fluid Physics and Transport Phenomena Conference

NASA Technical Reports Server (NTRS)

1999-01-01

This conference presents information to the scientific community on research results, future directions, and research opportunities in microgravity fluid physics and transport phenomena within NASA's microgravity research program. The conference theme is "The International Space Station." The conference publication consists of the full Proceedings of the 4th Microgravity Fluid Physics and Transport Phenomena Conference on CD-ROM, containing full papers presented at the conference. Ninety papers are presented in 21 technical sessions, and a special exposition session presents 32 posters describing the work of principal investigators new to NASA's program in this discipline. Eighty-eight papers and 25 posters are presented in their entirety on the CD-ROM.

A Rules-Based Service for Suggesting Visualizations to Analyze Earth Science Phenomena.

NASA Astrophysics Data System (ADS)

Prabhu, A.; Zednik, S.; Fox, P. A.; Ramachandran, R.; Maskey, M.; Shie, C. L.; Shen, S.

2016-12-01

Current Earth Science Information Systems lack support for new or interdisciplinary researchers, who may be unfamiliar with the domain vocabulary or the breadth of relevant data available. We need to evolve the current information systems, to reduce the time required for data preparation, processing and analysis. This can be done by effectively salvaging the "dark" resources in Earth Science. We assert that Earth science metadata assets are dark resources, information resources that organizations collect, process, and store for regular business or operational activities but fail to utilize for other purposes. In order to effectively use these dark resources, especially for data processing and visualization, we need a combination of domain, data product and processing knowledge, i.e. a knowledge base from which specific data operations can be performed. In this presentation, we describe a semantic, rules based approach to provide i.e. a service to visualize Earth Science phenomena, based on the data variables extracted using the "dark" metadata resources. We use Jena rules to make assertions about compatibility between a phenomena and various visualizations based on multiple factors. We created separate orthogonal rulesets to map each of these factors to the various phenomena. Some of the factors we have considered include measurements, spatial resolution and time intervals. This approach enables easy additions and deletions based on newly obtained domain knowledge or phenomena related information and thus improving the accuracy of the rules service overall.

Heavenly Bodies and Phenomena in Petroglyphs

NASA Astrophysics Data System (ADS)

Tokhatyan, Karen

2016-12-01

In Armenian culture are amply reflected realities connected with Universe. Their figurative expressions are also petroglyphs in which there are representations of solar signs, swastika, Moon crescend, planets, stars, star groups, constellations, Milky Way, Earth. Among heavenly and atmospheric phenomena are: eclipce, meteor, comet, ligthning, cloud, rain and rainbow. There are many products of scientific thinking: stellar maps, calendars, compasses, astronomical records, Zodiac signs and ideograms. Thousands of the Armenian petroglyphs that were created millennia ago by an indigenous ethnos - Armenians, point to the significant place of celestial bodies and luminaries, especially the Sun, stars, and stellar constellations in our ancestors' cosmological perceptions.

Robust Emergent Climate Phenomena Associated with the High-Sensitivity Tail

NASA Astrophysics Data System (ADS)

Boslough, M.; Levy, M.; Backus, G.

2010-12-01

Because the potential effects of climate change are more severe than had previously been thought, increasing focus on uncertainty quantification is required for risk assessment needed by policy makers. Current scientific efforts focus almost exclusively on establishing best estimates of future climate change. However, the greatest consequences occur in the extreme tail of the probability density functions for climate sensitivity (the “high-sensitivity tail”). To this end, we are exploring the impacts of newly postulated, highly uncertain, but high-consequence physical mechanisms to better establish the climate change risk. We define consequence in terms of dramatic change in physical conditions and in the resulting socioeconomic impact (hence, risk) on populations. Although we are developing generally applicable risk assessment methods, we have focused our initial efforts on uncertainty and risk analyses for the Arctic region. Instead of focusing on best estimates, requiring many years of model parameterization development and evaluation, we are focusing on robust emergent phenomena (those that are not necessarily intuitive and are insensitive to assumptions, subgrid-parameterizations, and tunings). For many physical systems, under-resolved models fail to generate such phenomena, which only develop when model resolution is sufficiently high. Our ultimate goal is to discover the patterns of emergent climate precursors (those that cannot be predicted with lower-resolution models) that can be used as a "sensitivity fingerprint" and make recommendations for a climate early warning system that would use satellites and sensor arrays to look for the various predicted high-sensitivity signatures. Our initial simulations are focused on the Arctic region, where underpredicted phenomena such as rapid loss of sea ice are already emerging, and because of major geopolitical implications associated with increasing Arctic accessibility to natural resources, shipping routes

Inverse Analysis of Cavitation Impact Phenomena on Structures

DTIC Science & Technology

2007-07-02

can occur within different types of dynamic water environments of structures. Case study analyses using experimental data are used to demonstrate the...cavitation impact phenomena, and ultimately, with cavitation erosion of structures within turbulent water environments. 02-07-2007 Memorandum Report...of dynamic water environments of structures. Case study analyses using experimental data are used to demonstrate the fundamentals of various aspects

Design and evaluation guidelines for Department of Energy facilities subjected to natural phenomena hazards

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

Kennedy, R.P.; Short, S.A.; McDonald, J.R.

1990-06-01

The Department of Energy (DOE) and the DOE Natural Phenomena Hazards Panel have developed uniform design and evaluation guidelines for protection against natural phenomena hazards at DOE sites throughout the United States. The goal of the guidelines is to assure that DOE facilities can withstand the effects of natural phenomena such as earthquakes, extreme winds, tornadoes, and flooding. The guidelines apply to both new facilities (design) and existing facilities (evaluation, modification, and upgrading). The intended audience is primarily the civil/structural or mechanical engineers conducting the design or evaluation of DOE facilities. The likelihood of occurrence of natural phenomena hazards atmore » each DOE site has been evaluated by the DOE Natural Phenomena Hazard Program. Probabilistic hazard models are available for earthquake, extreme wind/tornado, and flood. Alternatively, site organizations are encouraged to develop site-specific hazard models utilizing the most recent information and techniques available. In this document, performance goals and natural hazard levels are expressed in probabilistic terms, and design and evaluation procedures are presented in deterministic terms. Design/evaluation procedures conform closely to common standard practices so that the procedures will be easily understood by most engineers. Performance goals are expressed in terms of structure or equipment damage to the extent that: (1) the facility cannot function; (2) the facility would need to be replaced; or (3) personnel are endangered. 82 refs., 12 figs., 18 tabs.« less

Autoscopic phenomena and one's own body representation in dreams.

PubMed

Occhionero, Miranda; Cicogna, Piera Carla

2011-12-01

Autoscopic phenomena (AP) are complex experiences that include the visual illusory reduplication of one's own body. From a phenomenological point of view, we can distinguish three conditions: autoscopic hallucinations, heautoscopy, and out-of-body experiences. The dysfunctional pattern involves multisensory disintegration of personal and extrapersonal space perception. The etiology, generally either neurological or psychiatric, is different. Also, the hallucination of Self and own body image is present during dreams and differs according to sleep stage. Specifically, the representation of the Self in REM dreams is frequently similar to the perception of Self in wakefulness, whereas in NREM dreams, a greater polymorphism of Self and own body representation is observed. The parallels between autoscopic phenomena in pathological cases and the Self-hallucination in dreams will be discussed to further the understanding of the particular states of self awareness, especially the complex integration of different memory sources in Self and body representation. Copyright © 2011 Elsevier Inc. All rights reserved.

Initiating Young Children into Basic Astronomical Concepts and Phenomena

NASA Astrophysics Data System (ADS)

Kallery, M.

2010-07-01

In the present study we developed and implemented three units of activities aiming at acquainting very young children with basic astronomical concepts and phenomena such as the sphericity of the earth, the earth’s movements and the day/night cycle. The activities were developed by a group composed of a researcher/facilitator and six early-years teachers. In the activities children were presented with appropriate for their age scientific information along with conceptual tools such as a globe and an instructional video. Action research processes were used to optimize classroom practices and to gather useful information for the final shaping of the activities and the instruction materials. In these activities the adopted approach to learning can be characterized as socially constructed. The results indicated awareness of concepts and phenomena that the activities dealt with in high percentages of children, storage of the new knowledge in the long term memory and easy retrieval of it, and children’s enthusiasm for the subject.

Musical obsessions: a comprehensive review of neglected clinical phenomena.

PubMed

Taylor, Steven; McKay, Dean; Miguel, Euripedes C; De Mathis, Maria Alice; Andrade, Chittaranjan; Ahuja, Niraj; Sookman, Debbie; Kwon, Jun Soo; Huh, Min Jung; Riemann, Bradley C; Cottraux, Jean; O'Connor, Kieron; Hale, Lisa R; Abramowitz, Jonathan S; Fontenelle, Leonardo F; Storch, Eric A

2014-08-01

Intrusive musical imagery (IMI) consists of involuntarily recalled, short, looping fragments of melodies. Musical obsessions are distressing, impairing forms of IMI that merit investigation in their own right and, more generally, research into these phenomena may broaden our understanding of obsessive-compulsive disorder (OCD), which is phenomenologically and etiologically heterogeneous. We present the first comprehensive review of musical obsessions, based on the largest set of case descriptions ever assembled (N=96). Characteristics of musical obsessions are described and compared with normal IMI, musical hallucinations, and visual obsessional imagery. Assessment, differential diagnosis, comorbidity, etiologic hypotheses, and treatments are described. Musical obsessions may be under-diagnosed because they are not adequately assessed by current measures of OCD. Musical obsessions have been misdiagnosed as psychotic phenomena, which has led to ineffective treatment. Accurate diagnosis is important for appropriate treatment. Musical obsessions may respond to treatments that are not recommended for prototypic OCD symptoms. Copyright © 2014 Elsevier Ltd. All rights reserved.

Electrochemical Transport Phenomena in Hybrid Pseudocapacitors under Galvanostatic Cycling

DOE PAGES

d'Entremont, Anna L.; Girard, Henri -Louis; Wang, Hainan; ...

2015-11-18

Here, this study aims to provide insights into the electrochemical transport and interfacial phenomena in hybrid pseudocapacitors under galvanostatic cycling. Pseudocapacitors are promising electrical energy storage devices for applications requiring large power density. They also involve complex, coupled, and multiscale physical phenomena that are difficult to probe experimentally. The present study performed detailed numerical simulations for a hybrid pseudocapacitor with planar electrodes and binary, asymmetric electrolyte under various cycling conditions, based on a first-principles continuum model accounting simultaneously for charge storage by electric double layer (EDL) formation and by faradaic reactions with intercalation. Two asymptotic regimes were identified corresponding tomore » (i) dominant faradaic charge storage at low current and low frequency or (ii) dominant EDL charge storage at high current and high frequency. Analytical expressions for the intercalated ion concentration and surface overpotential were derived for both asymptotic regimes. Features of typical experimentally measured cell potential were physically interpreted. These insights could guide the optimization of hybrid pseudocapacitors.« less

Stochastic Car-Following Model for Explaining Nonlinear Traffic Phenomena

NASA Astrophysics Data System (ADS)

Meng, Jianping; Song, Tao; Dong, Liyun; Dai, Shiqiang

There is a common time parameter for representing the sensitivity or the lag (response) time of drivers in many car-following models. In the viewpoint of traffic psychology, this parameter could be considered as the perception-response time (PRT). Generally, this parameter is set to be a constant in previous models. However, PRT is actually not a constant but a random variable described by the lognormal distribution. Thus the probability can be naturally introduced into car-following models by recovering the probability of PRT. For demonstrating this idea, a specific stochastic model is constructed based on the optimal velocity model. By conducting simulations under periodic boundary conditions, it is found that some important traffic phenomena, such as the hysteresis and phantom traffic jams phenomena, can be reproduced more realistically. Especially, an interesting experimental feature of traffic jams, i.e., two moving jams propagating in parallel with constant speed stably and sustainably, is successfully captured by the present model.

Different Selection Pressures Give Rise to Distinct Ethnic Phenomena

PubMed Central

Moya, Cristina; Boyd, Robert

2015-01-01

Many accounts of ethnic phenomena imply that processes such as stereotyping, essentialism, ethnocentrism, and intergroup hostility stem from a unitary adaptation for reasoning about groups. This is partly justified by the phenomena’s co-occurrence in correlational studies. Here we argue that these behaviors are better modeled as functionally independent adaptations that arose in response to different selection pressures throughout human evolution. As such, different mechanisms may be triggered by different group boundaries within a single society. We illustrate this functionalist framework using ethnographic work from the Quechua-Aymara language boundary in the Peruvian Altiplano. We show that different group boundaries motivate different ethnic phenomena. For example, people have strong stereotypes about socioeconomic categories, which are not cooperative units, whereas they hold fewer stereotypes about communities, which are the primary focus of cooperative activity. We also show that, despite the cross-cultural importance of ethnolinguistic boundaries, the Quechua-Aymara linguistic distinction does not strongly motivate any of these intergroup processes. PMID:25731969

Modeling of nanosecond pulsed laser processing of polymers in air and water

NASA Astrophysics Data System (ADS)

Marla, Deepak; Zhang, Yang; Hattel, Jesper H.; Spangenberg, Jon

2018-07-01

Laser ablation of polymers in water is known to generate distinct surface characteristics as compared to that in air. In order to understand the role of ambient media during laser ablation of polymers, this paper aims to develop a physics-based model of the process considering the effect of ambient media. Therefore, in the present work, models are developed for laser ablation of polymers in air and water considering all the relevant physical phenomena such as laser–polymer interaction, plasma generation, plasma expansion and plasma shielding. The current work focuses on near-infrared laser radiation (λ = 1064 nm) of nanosecond pulse duration. The laser–polymer interaction at such wavelengths is purely photo-thermal in nature and the laser–plasma interaction is assumed to occur mainly by inverse-bremsstrahlung photon absorption. The computational model is based on the finite volume method using the Crank‑Nicholson scheme. The model predicts that underwater laser ablation results in subsurface heating effect in the polymer and confinement of the laser generated plasma, which makes it different from laser ablation in air. Plasma expansion velocities are much lower in water than in air. This results in an enhanced plasma shielding effect in the case of water. The predicted results of ablation depth versus fluence from the model are in qualitative agreement with those observed in experiments.

Nonlinear dynamic phenomena in the space shuttle thermal protection system

NASA Technical Reports Server (NTRS)

Housner, J. M.; Edighoffer, H. H.; Park, K. C.

1981-01-01

The development of an analysis for examining the nonlinear dynamic phenomena arising in the space shuttle orbiter tile/pad thermal protection system is presented. The tile/pad system consists of ceramic tiles bonded to the aluminum skin of the orbiter through a thin nylon felt pad. The pads are a soft nonlinear material which permits large strains and displays both hysteretic and nonlinear viscous damping. Application of the analysis to a square tile subjected to transverse sinusoidal motion of the orbiter skin is presented and the following nonlinear dynamic phenomena are considered: highly distorted wave forms, amplitude-dependent resonant frequencies which initially decrease and then increase with increasing amplitude of motion, magnification of substrate motion which is higher than would be expected in a similarly highly damped linear system, and classical parametric resonance instability.

Change Blindness Phenomena for Virtual Reality Display Systems.

PubMed

Steinicke, Frank; Bruder, Gerd; Hinrichs, Klaus; Willemsen, Pete

2011-09-01

In visual perception, change blindness describes the phenomenon that persons viewing a visual scene may apparently fail to detect significant changes in that scene. These phenomena have been observed in both computer-generated imagery and real-world scenes. Several studies have demonstrated that change blindness effects occur primarily during visual disruptions such as blinks or saccadic eye movements. However, until now the influence of stereoscopic vision on change blindness has not been studied thoroughly in the context of visual perception research. In this paper, we introduce change blindness techniques for stereoscopic virtual reality (VR) systems, providing the ability to substantially modify a virtual scene in a manner that is difficult for observers to perceive. We evaluate techniques for semiimmersive VR systems, i.e., a passive and active stereoscopic projection system as well as an immersive VR system, i.e., a head-mounted display, and compare the results to those of monoscopic viewing conditions. For stereoscopic viewing conditions, we found that change blindness phenomena occur with the same magnitude as in monoscopic viewing conditions. Furthermore, we have evaluated the potential of the presented techniques for allowing abrupt, and yet significant, changes of a stereoscopically displayed virtual reality environment.

Numerical characterisation of one-step and three-step solar air heating collectors used for cocoa bean solar drying.

PubMed

Orbegoso, Elder Mendoza; Saavedra, Rafael; Marcelo, Daniel; La Madrid, Raúl

2017-12-01

In the northern coastal and jungle areas of Peru, cocoa beans are dried using artisan methods, such as direct exposure to sunlight. This traditional process is time intensive, leading to a reduction in productivity and, therefore, delays in delivery times. The present study was intended to numerically characterise the thermal behaviour of three configurations of solar air heating collectors in order to determine which demonstrated the best thermal performance under several controlled operating conditions. For this purpose, a computational fluid dynamics model was developed to describe the simultaneous convective and radiative heat transfer phenomena under several operation conditions. The constructed computational fluid dynamics model was firstly validated through comparison with the data measurements of a one-step solar air heating collector. We then simulated two further three-step solar air heating collectors in order to identify which demonstrated the best thermal performance in terms of outlet air temperature and thermal efficiency. The numerical results show that under the same solar irradiation area of exposition and operating conditions, the three-step solar air heating collector with the collector plate mounted between the second and third channels was 67% more thermally efficient compared to the one-step solar air heating collector. This is because the air exposition with the surface of the collector plate for the three-step solar air heating collector former device was twice than the one-step solar air heating collector. Copyright © 2017 Elsevier Ltd. All rights reserved.

Analytical investigation of critical phenomena in MHD power generators

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

Not Available

1980-07-31

Critical phenomena in the Arnold Engineering Development Center (AEDC) High Performance Demonstration Experiment (HPDE) and the US U-25 Experiment, are analyzed. Also analyzed are the performance of a NASA-specified 500 MW(th) flow train and computations concerning critica issues for the scale-up of MHD Generators. The HPDE is characterized by computational simulations of both the nominal conditions and the conditions during the experimental runs. The steady-state performance is discussed along with the Hall voltage overshoots during the start-up and shutdown transients. The results of simulations of the HPDE runs with codes from the Q3D and TRANSIENT code families are compared tomore » the experimental results. The results of the simulations are in good agreement with the experimental data. Additional critica phenomena analyzed in the AEDC/HPDE are the optimal load schedules, parametric variations, the parametric dependence of the electrode voltage drops, the boundary layer behavior, near electrode phenomena with finite electrode segmentation, and current distribution in the end regions. The US U-25 experiment is characterized by computational simulations of the nominal operating conditions. The steady-state performance for the nominal design of the US U-25 experiment is analyzed, as is the dependence of performance on the mass flow rate. A NASA-specified 500 MW(th) MHD flow train is characterized for computer simulation and the electrical, transport, and thermodynamic properties at the inlet plane are analyzed. Issues for the scale-up of MHD power trains are discussed. The AEDC/HPDE performance is analyzed to compare these experimental results to scale-up rules.« less

Casting And Solidification Technology (CAST): Directional solidification phenomena in a metal model at reduced gravity

NASA Technical Reports Server (NTRS)

Mccay, M. H.

1988-01-01

The Casting and Solidification Technology (CAST) experiment will study the phenomena that occur during directional solidification of an alloy, e.g., constitutional supercooling, freckling, and dendrite coarsening. The reduced gravity environment of space will permit the individual phenomena to be examined with minimum complication from buoyancy driven flows.

Exploring Divisibility and Summability of 'Photon' Wave Packets in Nonlinear Optical Phenomena

NASA Technical Reports Server (NTRS)

Prasad, Narasimha; Roychoudhuri, Chandrasekhar

2009-01-01

Formulations for second and higher harmonic frequency up and down conversions, as well as multi photon processes directly assume summability and divisibility of photons. Quantum mechanical (QM) interpretations are completely congruent with these assumptions. However, for linear optical phenomena (interference, diffraction, refraction, material dispersion, spectral dispersion, etc.), we have a profound dichotomy. Most optical engineers innovate and analyze all optical instruments by propagating pure classical electromagnetic (EM) fields using Maxwell s equations and gives only lip-service to the concept "indivisible light quanta". Further, irrespective of linearity or nonlinearity of the phenomena, the final results are always registered through some photo-electric or photo-chemical effects. This is mathematically well modeled by a quadratic action (energy absorption) relation. Since QM does not preclude divisibility or summability of photons in nonlinear & multi-photon effects, it cannot have any foundational reason against these same possibilities in linear optical phenomena. It implies that we must carefully revisit the fundamental roots behind all light-matter interaction processes and understand the common origin of "graininess" and "discreteness" of light energy.

A Bayesian explanation of the ‘Uncanny Valley’ effect and related psychological phenomena

PubMed Central

Moore, Roger K.

2012-01-01

There are a number of psychological phenomena in which dramatic emotional responses are evoked by seemingly innocuous perceptual stimuli. A well known example is the ‘uncanny valley’ effect whereby a near human-looking artifact can trigger feelings of eeriness and repulsion. Although such phenomena are reasonably well documented, there is no quantitative explanation for the findings and no mathematical model that is capable of predicting such behavior. Here I show (using a Bayesian model of categorical perception) that differential perceptual distortion arising from stimuli containing conflicting cues can give rise to a perceptual tension at category boundaries that could account for these phenomena. The model is not only the first quantitative explanation of the uncanny valley effect, but it may also provide a mathematical explanation for a range of social situations in which conflicting cues give rise to negative, fearful or even violent reactions. PMID:23162690

Homogeneous dielectric barrier discharges in atmospheric air and its influencing factor

NASA Astrophysics Data System (ADS)

Ran, Junxia; Li, Caixia; Ma, Dong; Luo, Haiyun; Li, Xiaowei

2018-03-01

The stable homogeneous dielectric barrier discharge (DBD) is obtained in atmospheric 2-3 mm air gap. It is generated using center frequency 1 kHz high voltage power supply between two plane parallel electrodes with specific alumina ceramic plates as the dielectric barriers. The discharge characteristics are studied by a measurement of its electrical discharge parameters and observation of its light emission phenomena. The results show that a large single current pulse of about 200 μs duration appearing in each voltage pulse, and its light emission is radially homogeneous and covers the entire surface of the two electrodes. The homogeneous discharge generated is a Townsend discharge during discharge. The influences of applied barrier, its thickness, and surface roughness on the transition of discharge modes are studied. The results show that it is difficult to produce a homogeneous discharge using smooth plates or alumina plate surface roughness Ra < 100 nm even at a 1 mm air gap. If the alumina plate is too thin, the discharge also transits to filamentary discharge. If it is too thick, the discharge is too weak to observe. With the increase of air gap distance and applied voltage, the discharge can also transit from a homogeneous mode to a filamentary mode. In order to generate stable and homogeneous DBD at a larger air gap, proper dielectric material, dielectric thickness, and dielectric surface roughness should be used, and proper applied voltage amplitude and frequency should also be used.

Possible relationships between solar activity and meteorological phenomena

NASA Technical Reports Server (NTRS)

Bandeen, W. R. (Editor); Maran, S. P. (Editor)

1975-01-01

A symposium was conducted in which the following questions were discussed: (1) the evidence concerning possible relationships between solar activity and meteorological phenomena; (2) plausible physical mechanisms to explain these relationships; and (3) kinds of critical measurements needed to determine the nature of solar/meteorological relationships and/or the mechanisms to explain them, and which of these measurements can be accomplished best from space.

Radar Scan Strategies for the Patrick Air Force Base Weather Surveillance Radar, Model-74C, Replacement

NASA Technical Reports Server (NTRS)

Short, David

2008-01-01

The 45th Weather Squadron (45 WS) is replacing the Weather Surveillance Radar, Model 74C (WSR-74C) at Patrick Air Force Base (PAFB), with a Doppler, dual polarization radar, the Radtec 43/250. A new scan strategy is needed for the Radtec 43/250, to provide high vertical resolution data over the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) launch pads, while taking advantage of the new radar's advanced capabilities for detecting severe weather phenomena associated with convection within the 45 WS area of responsibility. The Applied Meteorology Unit (AMU) developed several scan strategies customized for the operational needs of the 45 WS. The AMU also developed a plan for evaluating the scan strategies in the period prior to operational acceptance, currently scheduled for November 2008.

Flow Pattern Phenomena in Two-Phase Flow in Microchannels

NASA Astrophysics Data System (ADS)

Keska, Jerry K.; Simon, William E.

2004-02-01

Space transportation systems require high-performance thermal protection and fluid management techniques for systems ranging from cryogenic fluid management devices to primary structures and propulsion systems exposed to extremely high temperatures, as well as for other space systems such as cooling or environment control for advanced space suits and integrated circuits. Although considerable developmental effort is being expended to bring potentially applicable technologies to a readiness level for practical use, new and innovative methods are still needed. One such method is the concept of Advanced Micro Cooling Modules (AMCMs), which are essentially compact two-phase heat exchangers constructed of microchannels and designed to remove large amounts of heat rapidly from critical systems by incorporating phase transition. The development of AMCMs requires fundamental technological advancement in many areas, including: (1) development of measurement methods/systems for flow-pattern measurement/identification for two-phase mixtures in microchannels; (2) development of a phenomenological model for two-phase flow which includes the quantitative measure of flow patterns; and (3) database development for multiphase heat transfer/fluid dynamics flows in microchannels. This paper focuses on the results of experimental research in the phenomena of two-phase flow in microchannels. The work encompasses both an experimental and an analytical approach to incorporating flow patterns for air-water mixtures flowing in a microchannel, which are necessary tools for the optimal design of AMCMs. Specifically, the following topics are addressed: (1) design and construction of a sensitive test system for two-phase flow in microchannels, one which measures ac and dc components of in-situ physical mixture parameters including spatial concentration using concomitant methods; (2) data acquisition and analysis in the amplitude, time, and frequency domains; and (3) analysis of results

Non-Grammatical Reflexive Binding Phenomena: The Case of Japanese.

ERIC Educational Resources Information Center

Sakakibara, Sonoko

Two non-syntactic phenomena of Japanese reflexive binding by "zibun" ("self") are analyzed with respect to a pragmatic use condition on "zibun," a culture-specific condition, and the Maxim of Politeness (Fukada 1986). The first phenomenon is the tendency by native speakers of Japanese to avoid referring to an honored…

Developing Critical Thinking through the Study of Paranormal Phenomena.

ERIC Educational Resources Information Center

Wesp, Richard; Montgomery, Kathleen

1998-01-01

Argues that accounts of paranormal phenomena can serve as an ideal medium in which to encourage students to develop critical-thinking skills. Describes a cooperative-learning approach used to teach critical thinking in a course on paranormal events. Reports that critical-thinking skills increased and that the course received favorable student…

Investigating Dissolution and Precipitation Phenomena with a Smartphone Microscope

ERIC Educational Resources Information Center

Lumetta, Gregg J.; Arcia, Edgar

2016-01-01

A novel smartphone microscope can be used to observe the dissolution and crystallization of sodium chloride at a microscopic level. Observation of these seemingly simple phenomena through the microscope at 100× magnification can actually reveal some surprising behavior. These experiments offer the opportunity to discuss some basic concepts such as…

The Fragility of Interdependency: Coupled Networks Switching Phenomena

NASA Astrophysics Data System (ADS)

Stanley, H. Eugene

2013-03-01

Recent disasters ranging from abrupt financial ``flash crashes'' and large-scale power outages to sudden death among the elderly dramatically exemplify the fact that the most dangerous vulnerability is hiding in the many interdependencies among different networks. In the past year, we have quantified failures in model of interconnected networks, and demonstrated the need to consider mutually dependent network properties in designing resilient systems. Specifically, we have uncovered new laws governing the nature of switching phenomena in coupled networks, and found that phenomena that are continuous ``second order'' phase transitions in isolated networks become discontinuous abrupt ``first order'' transitions in interdependent networks [S. V. Buldyrev, R. Parshani, G. Paul, H. E. Stanley, and S. Havlin, ``Catastrophic Cascade of Failures in Interdependent Networks,'' Nature 464, 1025 (2010); J. Gao, S. V. Buldyrev, H. E. Stanley, and S. Havlin, ``Novel Behavior of Networks Formed from Interdependent Networks,'' Nature Physics 8, 40 (2012). We conclude by discussing the network basis for understanding sudden death in the elderly, and the possibility that financial ``flash crashes'' are not unlike the catastrophic first-order failure incidents occurring in coupled networks. Specifically, we study the coupled networks that are responsible for financial fluctuations. It appears that ``trend switching phenomena'' that we uncover are remarkably independent of the scale over which they are analyzed. For example, we find that the same laws governing the formation and bursting of the largest financial bubbles also govern the tiniest finance bubbles, over a factor of 1,000,000,000 in time scale [T. Preis, J. Schneider, and H. E. Stanley, ``Switching Processes in Financial Markets,'' Proc. Natl. Acad. Sci. USA 108, 7674 (2011); T. Preis and H. E. Stanley, ``Bubble Trouble: Can a Law Describe Bubbles and Crashes in Financial Markets?'' Physics World 24, No. 5, 29 (May 2011

TRANSIENT LUNAR PHENOMENA: REGULARITY AND REALITY

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

Crotts, Arlin P. S.

2009-05-20

Transient lunar phenomena (TLPs) have been reported for centuries, but their nature is largely unsettled, and even their existence as a coherent phenomenon is controversial. Nonetheless, TLP data show regularities in the observations; a key question is whether this structure is imposed by processes tied to the lunar surface, or by terrestrial atmospheric or human observer effects. I interrogate an extensive catalog of TLPs to gauge how human factors determine the distribution of TLP reports. The sample is grouped according to variables which should produce differing results if determining factors involve humans, and not reflecting phenomena tied to the lunarmore » surface. Features dependent on human factors can then be excluded. Regardless of how the sample is split, the results are similar: {approx}50% of reports originate from near Aristarchus, {approx}16% from Plato, {approx}6% from recent, major impacts (Copernicus, Kepler, Tycho, and Aristarchus), plus several at Grimaldi. Mare Crisium produces a robust signal in some cases (however, Crisium is too large for a 'feature' as defined). TLP count consistency for these features indicates that {approx}80% of these may be real. Some commonly reported sites disappear from the robust averages, including Alphonsus, Ross D, and Gassendi. These reports begin almost exclusively after 1955, when TLPs became widely known and many more (and inexperienced) observers searched for TLPs. In a companion paper, we compare the spatial distribution of robust TLP sites to transient outgassing (seen by Apollo and Lunar Prospector instruments). To a high confidence, robust TLP sites and those of lunar outgassing correlate strongly, further arguing for the reality of TLPs.« less

AIRS Ozone Burden During Antarctic Winter: Time Series from 8/1/2005 to 9/30/2005

NASA Technical Reports Server (NTRS)

2007-01-01

[figure removed for brevity, see original site] Click on the image for movie of AIRS Ozone Burden During Antarctic Winter

AIRS provides a daily global 3-dimensional view of Earth's ozone layer. Since AIRS observes in the thermal infrared spectral range, it also allows scientists to view from space the Antarctic ozone hole for the first time continuously during polar winter. This image sequence captures the intensification of the annual ozone hole in the Antarctic Polar Vortex.

The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

Neuropsychiatric phenomena in the medieval text Cantigas de Santa Maria.

PubMed

Gondim, Francisco De Assis Aquino; Griesbach, Sarah H; Thomas, Florian P

2015-05-12

To discuss the neuropsychiatric phenomena described in Cantigas de Santa Maria (Canticles of St. Mary [CSM]). CSM is a collection of 427 canticles composed in Galician-Portuguese between 1252 and 1284 at the Court of King Alfonso X the Wise of Spain (1221-1284). The canticles (of which 9 are repeated) include devotional and liturgical poems and 353 narrative stories consisting mainly of depictions of Marian miracles. Most are set to music and many are illustrated. We reviewed the canticles for description of miracles and other neuropsychiatric phenomena. Two neurologists reached a consensus about the descriptions. Of the 353 miracles, 279 medically relevant facts (from 187 canticles) and 25 instances of resurrection were reported. Possible neuropsychiatric conditions were described in 98 canticles. Physicians were mentioned in 16 narratives. The most common neurologic conditions detailed were blindness (n = 17), dystonia, weakness, and deformities (n = 20). Other common conditions included psychosis (n = 15), speech disorder/deaf-mutism (n = 12), infections (n = 15), sexual dysfunction/infertility/obstetrical-gynecologic issues (n = 18), head trauma (n = 5), ergotism/St. Anthony's fire (n = 7), and others. There were 9 instances of prodromic mystical experiences/hallucinations heralding death. While limited by retrospection and interpretation of neuropsychiatric phenomena in the medieval context, these short accounts are among the first descriptions of neuropsychiatric conditions in early Portuguese/Galician. They reflect how medieval societies used rational and irrational approaches to understand occurrences in their lives. © 2015 American Academy of Neurology.

Electrostatic Phenomena on Planetary Surfaces

NASA Astrophysics Data System (ADS)

Calle, Carlos I.

2017-02-01

The diverse planetary environments in the solar system react in somewhat different ways to the encompassing influence of the Sun. These different interactions define the electrostatic phenomena that take place on and near planetary surfaces. The desire to understand the electrostatic environments of planetary surfaces goes beyond scientific inquiry. These environments have enormous implications for both human and robotic exploration of the solar system. This book describes in some detail what is known about the electrostatic environment of the solar system from early and current experiments on Earth as well as what is being learned from the instrumentation on the space exploration missions (NASA, European Space Agency, and the Japanese Space Agency) of the last few decades. It begins with a brief review of the basic principles of electrostatics.

Amplitude various angles (AVA) phenomena in thin layer reservoir: Case study of various reservoirs

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

Nurhandoko, Bagus Endar B., E-mail: bagusnur@bdg.centrin.net.id, E-mail: bagusnur@rock-fluid.com; Rock Fluid Imaging Lab., Bandung; Susilowati, E-mail: bagusnur@bdg.centrin.net.id, E-mail: bagusnur@rock-fluid.com

2015-04-16

Amplitude various offset is widely used in petroleum exploration as well as in petroleum development field. Generally, phenomenon of amplitude in various angles assumes reservoir’s layer is quite thick. It also means that the wave is assumed as a very high frequency. But, in natural condition, the seismic wave is band limited and has quite low frequency. Therefore, topic about amplitude various angles in thin layer reservoir as well as low frequency assumption is important to be considered. Thin layer reservoir means the thickness of reservoir is about or less than quarter of wavelength. In this paper, I studied aboutmore » the reflection phenomena in elastic wave which considering interference from thin layer reservoir and transmission wave. I applied Zoeppritz equation for modeling reflected wave of top reservoir, reflected wave of bottom reservoir, and also transmission elastic wave of reservoir. Results show that the phenomena of AVA in thin layer reservoir are frequency dependent. Thin layer reservoir causes interference between reflected wave of top reservoir and reflected wave of bottom reservoir. These phenomena are frequently neglected, however, in real practices. Even though, the impact of inattention in interference phenomena caused by thin layer in AVA may cause inaccurate reservoir characterization. The relation between classes of AVA reservoir and reservoir’s character are different when effect of ones in thin reservoir and ones in thick reservoir are compared. In this paper, I present some AVA phenomena including its cross plot in various thin reservoir types based on some rock physics data of Indonesia.« less

Protein Crystallization: Specific Phenomena and General Insights on Crystallization Kinetics

NASA Technical Reports Server (NTRS)

Rosenberger, F.

1998-01-01

Experimental and simulation studies of the nucleation and growth kinetics of proteins have revealed phenomena that are specific for macromolecular crystallization, and others that provide a more detailed understanding of solution crystallization in general. The more specific phenomena, which include metastable liquid-liquid phase separations and gelation prior to solid nucleation, are due to the small ratio of the intermolecular interaction-range to the size of molecules involved. The apparently more generally applicable mechanisms include the cascade-like formation of macrosteps, as an intrinsic morphological instability that roots in the coupled bulk transport and nonlinear interface kinetics in systems with mixed growth rate control. Analyses of this nonlinear response provide (a) criteria for the choice of bulk transport conditions to minimize structural defect formation, and (b) indications that the "slow" protein crystallization kinetics stems from the mutual retardation of growth steps.

Preface: MHD wave phenomena in the solar interior and atmosphere

NASA Astrophysics Data System (ADS)

Fedun, Viktor; Srivastava, A. K.

2018-01-01

The Sun is our nearest star and this star produces various plasma wave processes and energetic events. These phenomena strongly influence interplanetary plasma dynamics and contribute to space-weather. The understanding of solar atmospheric dynamics requires hi-resolution modern observations which, in turn, further advances theoretical models of physical processes in the solar interior and atmosphere. In particular, it is essential to connect the magnetohydrodynamic (MHD) wave processes with the small and large-scale solar phenomena vis-a-vis transport of energy and mass. With the advent of currently available and upcoming high-resolution space (e.g., IRIS, SDO, Hinode, Aditya-L1, Solar-C, Solar Orbiter), and ground-based (e.g., SST, ROSA, NLST, Hi-C, DKIST, EST, COSMO) observations, solar physicists are able to explore exclusive wave processes in various solar magnetic structures at different spatio-temporal scales.

Steam-air blown bubbling fluidized bed biomass gasification (BFBBG): Multi-scale models and experimental validation

DOE PAGES

Bates, Richard B.; Ghoniem, Ahmed F.; Jablonski, Whitney S.; ...

2017-02-02

During fluidized bed biomass gasification, complex gas-solid mixing patterns and numerous chemical and physical phenomena make identification of optimal operating conditions challenging. In this work, a parametric experimental campaign was carried out alongside the development of a coupled reactor network model which successfully integrates the individually validated sub-models to predict steady-state reactor performance metrics and outputs. The experiments utilized an integrated gasification system consisting of an externally-heated, bench-scale, 4-in., 5 kWth, fluidized bed steam/air blown gasifier fed with woody biomass equipped with a molecular beam mass spectrometer to directly measure tar species. The operating temperature (750-850°C) and air/fuel equivalence ratiomore » (ER = 0-0.157) were independently varied to isolate their effects. Elevating temperature is shown to improve the char gasification rate and reduce tar concentrations. In conclusion, air strongly impacts the composition of tar, accelerating the conversion of lighter polycyclic-aromatic hydrocarbons into soot precursors, while also improving the overall carbon conversion.« less

Fluor Daniel Hanford implementation plan for DOE Order 5480.28, Natural phenomena hazards mitigation

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

Conrads, T.J.

1997-09-12

Natural phenomena hazards (NPH) are unexpected acts of nature that pose a threat or danger to workers, the public, or the environment. Earthquakes, extreme winds (hurricane and tornado), snow, flooding, volcanic ashfall, and lightning strikes are examples of NPH that could occur at the Hanford Site. U.S. Department of Energy (DOE) policy requires facilities to be designed, constructed, and operated in a manner that protects workers, the public, and the environment from hazards caused by natural phenomena. DOE Order 5480.28, Natural Phenomena Hazards Mitigation, includes rigorous new natural phenomena criteria for the design of new DOE facilities, as well asmore » for the evaluation and, if necessary, upgrade of existing DOE facilities. The Order was transmitted to Westinghouse Hanford Company in 1993 for compliance and is also identified in the Project Hanford Management Contract, Section J, Appendix C. Criteria and requirements of DOE Order 5480.28 are included in five standards, the last of which, DOE-STD-1023, was released in fiscal year 1996. Because the Order was released before all of its required standards were released, enforcement of the Order was waived pending release of the last standard and determination of an in-force date by DOE Richland Operations Office (DOE-RL). Agreement also was reached between the Management and Operations Contractor and DOE-RL that the Order would become enforceable for new structures, systems, and components (SSCS) 60 days following issue of a new order-based design criteria in HNF-PRO-97, Engineering Design and Evaluation. The order also requires that commitments addressing existing SSCs be included in an implementation plan that is to be issued 1 year following the release of the last standard. Subsequently, WHC-SP-1175, Westinghouse Hanford Company Implementation Plan for DOE Order 5480.28, Natural Phenomena Hazards Mitigation, Rev. 0, was issued in November 1996, and this document, HNF-SP-1175, Fluor Daniel Hanford

Complex Synchronization Phenomena in Ecological Systems

NASA Astrophysics Data System (ADS)

Stone, Lewi; Olinky, Ronen; Blasius, Bernd; Huppert, Amit; Cazelles, Bernard

2002-07-01

Ecological and biological systems provide us with many striking examples of synchronization phenomena. Here we discuss a number of intriguing cases and attempt to explain them taking advantage of a modelling framework. One main focus will concern synchronized ecological end epidemiological cycles which have Uniform Phase growth associated with their regular recurrence, and Chaotic Amplitudes - a feature we term UPCA. Examples come from different areas and include decadal cycles of small mammals, recurrent viral epidemics such as childhood infections (eg., measles), and seasonally driven phytoplankton blooms observed in lakes and the oceans. A more detailed theoretical analysis of seasonally synchronized chaotic population cycles is presented.

Graphene Visualizes the Ion Distribution on Air-Cleaved Mica.

PubMed

Bampoulis, Pantelis; Sotthewes, Kai; Siekman, Martin H; Zandvliet, Harold J W; Poelsema, Bene

2017-03-06

The distribution of potassium (K + ) ions on air-cleaved mica is important in many interfacial phenomena such as crystal growth, self-assembly and charge transfer on mica. However, due to experimental limitations to nondestructively probe single ions and ionic domains, their exact lateral organization is yet unknown. We show, by the use of graphene as an ultra-thin protective coating and scanning probe microscopies, that single potassium ions form ordered structures that are covered by an ice layer. The K + ions prefer to minimize the number of nearest neighbour K + ions by forming row-like structures as well as small domains. This trend is a result of repulsive ionic forces between adjacent ions, weakened due to screening by the surrounding water molecules. Using high resolution conductive atomic force microscopy maps, the local conductance of the graphene is measured, revealing a direct correlation between the K + distribution and the structure of the ice layer. Our results shed light on the local distribution of ions on the air-cleaved mica, solving a long-standing enigma. They also provide a detailed understanding of charge transfer from the ionic domains towards graphene.

Numerical study of turbulence-influence mechanism on arc characteristics in an air direct current circuit breaker

NASA Astrophysics Data System (ADS)

Wu, Mingliang; Yang, Fei; Rong, Mingzhe; Wu, Yi; Qi, Yang; Cui, Yufei; Liu, Zirui; Guo, Anxiang

2016-04-01

This paper focuses on the numerical investigation of arc characteristics in an air direct current circuit breaker (air DCCB). Using magneto-hydrodynamics (MHD) theory, 3D laminar model and turbulence model are constructed and calculated. The standard k-epsilon model is utilized to consider the turbulence effect in the arc chamber of the DCCB. Several important phenomena are found: the arc column in the turbulence-model case is more extensive, moves much more slowly than the counterpart in the laminar-model case, and shows stagnation at the entrance of the chamber, unlike in the laminar-model case. Moreover, the arc voltage in the turbulence-model case is much lower than in the laminar-model case. However, the results in the turbulence-model case show a much better agreement with the results of the breaking experiments under DC condition than in the laminar-model case, which is contradictory to the previous conclusions from the arc researches of both the low-voltage circuit breaker and the sulfur hexafluoride (SF6) nozzle. First, in the previous air-arc research of the low-voltage circuit breaker, it is assumed that the air plasma inside the chamber is in the state of laminar, and the laminar-model application gives quite satisfactory results compared with the experiments, while in this paper, the laminar-model application works badly. Second, the turbulence-model application in the arc research of the SF6-nozzle performs much better and gives higher arc voltage than the laminar-model application does, whereas in this paper, the turbulence-model application predicts lower arc voltage than the laminar-model application does. Based on the analysis of simulation results in detail, the mechanism of the above phenomena is revealed. The transport coefficients are strongly changed by turbulence, which will enhance the arc diffusion and make the arc volume much larger. Consequently, the arc appearance and the distribution of Lorentz force in the turbulence-model case

Binding Phenomena within a Reductionist Theory of Grammatical Dependencies

ERIC Educational Resources Information Center

Drummond, Alex

2011-01-01

This thesis investigates the implications of binding phenomena for the development of a reductionist theory of grammatical dependencies. The starting point is the analysis of binding and control in Hornstein (2001, 2009). A number of revisions are made to this framework in order to develop a simpler and empirically more successful account of…

α-, β-phenomena in the post-symmetry break for the flow past a circular cylinder

NASA Astrophysics Data System (ADS)

Kalita, Jiten C.; Sen, Shuvam

2017-03-01

In the existing literature, the so-called α- and β-phenomena have been reported only for the early stages for the flow past an impulsively started circular cylinder. The current study endeavours to explore the possible existence of these phenomena even in the later stages of the flow. The flow is computed using a recently developed compact finite difference method for the biharmonic form of the two-dimensional Navier-Stokes equations for a wide range of Reynolds numbers (Re). We establish that these secondary phenomena not only appear once the wake becomes asymmetric but also periodically during the post-vortex shedding period for Re = 1000. Further, the recently reported sub-α- and sub-β-phenomena for Re = 5000 at the tertiary level during the early stages of the flow could be identified even during the later stages of the flow as well. The formation of these tertiary structures has been explained through a detailed theoretical characterization of the topological aspects of the boundary layer separation. Both qualitative and quantitative results are provided to substantiate our claim.

Electromagnetic phenomena in granular flows in the laboratory and dusty plasmas in geophysics and astrophysics

NASA Astrophysics Data System (ADS)

Lathrop, Daniel; Eiskowitz, Skylar; Rojas, Ruben

2017-11-01

In clouds of suspended particles, collisions electrify particles and the clouds produce electric potential differences over large scales. This is seen in the atmosphere as lightning in thunderstorms, thundersnow, dust storms, and volcanic ash plumes, but it is a general phenomena in granular systems. The electrification process is not well understood. To investigate the relative importance of particle material properties and collective phenomena in granular and atmospheric electrification, we used several tabletop experiments that excite particle-laden flows. Various electromagnetic phenomena ensue. Measured electric fields result from capacitive and direct charge transfer to electrodes. These results suggest that while particle properties do matter (as previous investigations have shown), macroscopic electrification of granular flows is somewhat material independent and large-scale collective phenomena play a major role. As well, our results on charge separation and Hall effects suggest a very different view of the dynamics of clouds, planetary rings, and cold accretion disks in proto-planetary systems. We gratefully acknowledge past funding from the Julian Schwinger Foundation as well as the Ph.D. work of Freja Nordsiek.

A Photochemical Reactor for the Study of Kinetics and Adsorption Phenomena

ERIC Educational Resources Information Center

Poce-Fatou, J. A.; Gil, M. L. A.; Alcantara, R.; Botella, C.; Martin, J.

2004-01-01

The interaction between light and matter is examined with the help of a photochemical experiment. This experiment is useful for the investigation of heterogeneous catalysis, semiconductor properties and adsorption phenomena.

Migration and sorption phenomena in packaged foods.

PubMed

Gnanasekharan, V; Floros, J D

1997-10-01

Rapidly developing analytical capabilities and continuously evolving stringent regulations have made food/package interactions a subject of intense research. This article focuses on: (1) the migration of package components such as oligomers and monomers, processing aids, additives, and residual reactants in to packaged foods, and (2) sorption of food components such as flavors, lipids, and moisture into packages. Principles of diffusion and thermodynamics are utilized to describe the mathematics of migration and sorption. Mathematical models are developed from first principles, and their applicability is illustrated using numerical simulations and published data. Simulations indicate that available models are system (polymer-penetrant) specific. Furthermore, some models best describe the early stages of migration/sorption, whereas others should be used for the late stages of these phenomena. Migration- and/or sorption-related problems with respect to glass, metal, paper-based and polymeric packaging materials are discussed, and their importance is illustrated using published examples. The effects of migrating and absorbed components on food safety, quality, and the environment are presented for various foods and packaging materials. The impact of currently popular packaging techniques such as microwavable, ovenable, and retortable packaging on migration and sorption are discussed with examples. Analytical techniques for investigating migration and sorption phenomena in food packaging are critically reviewed, with special emphasis on the use and characteristics of food-simulating liquids (FSLs). Finally, domestic and international regulations concerning migration in packaged foods, and their impact on food packaging is briefly presented.

Initial aging phenomena in copper-chromium alloys

NASA Technical Reports Server (NTRS)

Suzuki, H.; Motohiro, K.

1985-01-01

The effects of quenching and aging temperatures on the initial aging curves of Cu-Cr alloy were examined mainly by means of electrical resistivity measurements. Three Cu-Cr alloy specimens having 0.24, 0.74, and 1.0% Cr were solution-treated at 950-1050 C, quenched into ice-water, and subsequently aged at 300-500 C. The results were as follows: (1) At the very early stage of aging (within about 30 sec), an abrupt decrease of resistivity with lowering aging tempratures. (T sub A) and rising solution temperatures (T sub S) was observed at (T sub A) up to about 400 C. In contrast, a transient increase of resistivity with rising T sub A and lowering T sub S was observed at T sub A from about 450 to 500 C. These phenomena seem to be caused by a rapid formation of solute clusters and the reversion of clusters formed during quenching, which are enhanced by quenched-in vacancies, respectively. (2) The amount of precipitation increased at the latter stage of aging with rising T sub S and T sub A as generally expected, where T sub S was not so high as to form secondary defects. (3) As a result, the initial aging phenomena in Cr-Cr alloy were revealed to be complicated against expectations. This was considered to be due to the migration energy of vacancies so larger in Cu-base.

Interface-Driven Phenomena in Solids: Thermodynamics, Kinetics and Chemistry

DOE PAGES

Abdeljawad, Fadi; Foiles, Stephen M.

2016-05-04

The study of materials interfaces dates back over a century. In solid systems and from an engineering perspective, free surfaces and internal (grain and/or phase) boundaries influence a wide range of properties, such as thermal, electrical and optical transport, and mechanical ones. The properties and the role of interfaces has been discussed extensively in various reviews such as by Sutton and Balluffi. As the characteristic feature size of a materials system (i.e., grain size) is decreased to the nanometer scale, interface-driven physics is expected to dominate due to the increased density of such planar defects. Moreover, interfacial attributes, thermodynamics, andmore » mobility play a key role in phase transformations, such as solidification dynamics and structural transitions in solids, and in homogenization and microstructural evolution processes, such as grain growth, coarsening, and recrystallization. In summary, the set of articles published in this special topic titled: “Interface-Driven Phenomena in Solids: Thermodynamics, Kinetics and Chemistry” covers topics related to microstructure evolution, segregation/adsorption phenomena and interface interactions with other materials defects.« less

Interface-Driven Phenomena in Solids: Thermodynamics, Kinetics and Chemistry

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

Abdeljawad, Fadi; Foiles, Stephen M.

The study of materials interfaces dates back over a century. In solid systems and from an engineering perspective, free surfaces and internal (grain and/or phase) boundaries influence a wide range of properties, such as thermal, electrical and optical transport, and mechanical ones. The properties and the role of interfaces has been discussed extensively in various reviews such as by Sutton and Balluffi. As the characteristic feature size of a materials system (i.e., grain size) is decreased to the nanometer scale, interface-driven physics is expected to dominate due to the increased density of such planar defects. Moreover, interfacial attributes, thermodynamics, andmore » mobility play a key role in phase transformations, such as solidification dynamics and structural transitions in solids, and in homogenization and microstructural evolution processes, such as grain growth, coarsening, and recrystallization. In summary, the set of articles published in this special topic titled: “Interface-Driven Phenomena in Solids: Thermodynamics, Kinetics and Chemistry” covers topics related to microstructure evolution, segregation/adsorption phenomena and interface interactions with other materials defects.« less

Emergent Topological Phenomena in Thin Films of Pyrochlore Iridates

NASA Astrophysics Data System (ADS)

Yang, Bohm-Jung; Nagaosa, Naoto

2014-06-01

Because of the recent development of thin film and artificial superstructure growth techniques, it is possible to control the dimensionality of the system, smoothly between two and three dimensions. In this Letter we unveil the dimensional crossover of emergent topological phenomena in correlated topological materials. In particular, by focusing on the thin film of pyrochlore iridate antiferromagnets grown along the [111] direction, we demonstrate that the thin film can have a giant anomalous Hall conductance, proportional to the thickness of the film, even though there is no Hall effect in 3D bulk material. Moreover, in the case of ultrathin films, a quantized anomalous Hall conductance can be observed, despite the fact that the system is an antiferromagnet. In addition, we uncover the emergence of a new topological phase, the nontrivial topological properties of which are hidden in the bulk insulator and manifest only in thin films. This shows that the thin film of correlated topological materials is a new platform to search for unexplored novel topological phenomena.

Social Justice Is in the Air: Teaching Climate Change and Air Pollution with Scientific and Social Inquiry

NASA Astrophysics Data System (ADS)

Hahnenberger, M.

2014-12-01

The intersection of environmental with social problems is a growing area of concern for scientists, policy makers, and citizens. Climate change and air pollution are two current environmental issues holding the public's attention which require collaboration of all stakeholders to create meaningful solutions. General education science courses are critical venues to engage students in the intersection of science with society. Effective teaching methods for these intersections include case studies, gallery walks, and town hall meetings. A case study from California explores how air quality has greatly improved in Los Angeles in the past 20 years, however residents of neighborhoods with lower socioeconomic status are still exposed to high levels of air pollutants. Students analyze scientific and health data to develop understanding and expertise in the problem, and are then tasked with developing a cost-benefit analysis of solutions. Gallery walks can be used to connect natural phenomena, such as hurricanes and severe weather, with their human impacts. Students bring their personal experiences with disasters and recovery to analyze how societies should deal with the changing climate and weather risks in their region, the country, or across the world. Town hall meetings allow students to gain expertise and perspective while embodying a role as a particular stakeholder in a climate mitigation or adaptation issue. A successful application of this method is a discussion of whether a resort community should be rebuilt on a barrier island after being destroyed in a category 3 hurricane. Stakeholders which students take on as roles have included climate scientists, homeowners, emergency managers, meteorologists, and others. Including distinct connections to social issues in introductory science courses helps students to not only engage with the material in a deeper way, but also helps to create critical thinkers who will become better citizens for tomorrow.

An investigation of relationships between meso- and synoptic-scale phenomena

NASA Technical Reports Server (NTRS)

Scoggins, J. R.; Wood, J. E.; Fuelberg, H. E.; Read, W. L.

1972-01-01

Methods based on the vorticity equation, the adiabatic method, the curvature of the vertical wind profile, and the structure of synoptic waves are used to determine areas of positive vertical motion in the mid-troposphere for a period in each season. Parameters indicative of low-level moisture and conditional instability are areas in which mesoscale systems may be present. The best association between mesoscale and synoptic-scale phenomena was found for a period during December when synoptic-scale systems were well developed. A good association between meso- and synoptic-scale events also was found for a period during March, while the poorest association was found for a June period. Daytime surface heating apparently is an important factor in the formation of mesoscale systems during the summer. It is concluded that the formation of mesoscale phenomena may be determined essentially from synoptic-scale conditions during winter, late fall, and early spring.

Visualizing Time-Varying Phenomena In Numerical Simulations Of Unsteady Flows

NASA Technical Reports Server (NTRS)

Lane, David A.

1996-01-01

Streamlines, contour lines, vector plots, and volume slices (cutting planes) are commonly used for flow visualization. These techniques are sometimes referred to as instantaneous flow visualization techniques because calculations are based on an instant of the flowfield in time. Although instantaneous flow visualization techniques are effective for depicting phenomena in steady flows,they sometimes do not adequately depict time-varying phenomena in unsteady flows. Streaklines and timelines are effective visualization techniques for depicting vortex shedding, vortex breakdown, and shock waves in unsteady flows. These techniques are examples of time-dependent flow visualization techniques, which are based on many instants of the flowfields in time. This paper describes the algorithms for computing streaklines and timelines. Using numerically simulated unsteady flows, streaklines and timelines are compared with streamlines, contour lines, and vector plots. It is shown that streaklines and timelines reveal vortex shedding and vortex breakdown more clearly than instantaneous flow visualization techniques.

Preface to special issue: Layered Phenomena in the Mesopause Region

NASA Astrophysics Data System (ADS)

Chu, Xinzhao; Marsh, Daniel R.

2017-09-01

Historically, the Layered Phenomena in the Mesopause Region (LPMR) workshops have focused on studies of mesospheric clouds and their related science, including spectacular noctilucent clouds (NLCs), polar mesospheric clouds (PMCs), and polar mesospheric summer echoes (PMSEs). This is because, in the pre-technology era, these high-altitude ( 85 km) clouds revealed the existence of substance above the 'normal atmosphere' - our near-space environment is not empty! The occurrence and nature of these clouds have commanded the attention of atmospheric and space scientists for generations. Modern technologies developed in the last 50 years have enabled scientists to significantly advance our understanding of these layered phenomena. Satellite observations expanded these studies to global scales, while lidar and radar observations from the ground enabled fine-scale studies. The launch of the Aeronomy of Ice in the Mesosphere (AIM) satellite in 2007 brought mesospheric cloud research to a more mature level.

The role of family phenomena in children and adolescents with attention deficit hyperactivity disorder.

PubMed

Paidipati, Cynthia P; Deatrick, Janet A

2015-02-01

Previous research suggests that families are integral to the understanding of children and adolescents with attention deficit hyperactivity disorder (ADHD). The purpose of this article is to identify family phenomena related to children and adolescents with ADHD and highlight research findings that intersect family phenomena with the care and treatment of ADHD in youth. A literature review was conducted at the University of Pennsylvania in spring of 2014 using an online library system. The four major databases utilized are Cumulative Index to Nursing and Allied Health Literature (CINAHL), Ovid Medline, Scopus, and Psyc-INFO. A wide array of family-related concepts are identified in the literature and represent a multifaceted and dynamic range of family phenomena related to ADHD youth. Four major themes emerged in the literature, including family stress and strain, parenting practices and caregiver health, family relationships, and family processes related to ADHD management. Different cultural and ethnic groups are reflected in the studies, but the majority of participants are self-identified Caucasian. As a collective, the research findings suggest family-related phenomena are essential and relevant to the investigation of children and adolescents with ADHD and worthwhile to explore in future research endeavors, especially in diverse populations. © 2014 Wiley Periodicals, Inc.

Electrokinetic phenomena and dielectrophoresis in charged colloidal suspensions

NASA Astrophysics Data System (ADS)

Huang, J. P.; Karttunen, Mikko; Yu, K. W.; Dong, L.

2003-03-01

AC electrokinetic phenomena, i.e., electrorotation, dielectrophoresis and traveling wave dielectrophoresis, have gained an increasing amount of attention. This is due to their wide range of applications from cancer research to identifying and separating parasites, cell populations and viruses, and even to design of nanomotors. Despite the number of applications, there is need for a theory that treats the different aspects of electrokinetic phenomena on an equal footing starting from the general underlying physical principles. Here, we present a theoretical study of dielectrophoretic (DEP) crossover spectrum of two polarizable particles under the action of a nonuniform AC electric field. For two approaching particles, the mutual polarization interaction yields a change in their respective dipole moments, and hence, in the DEP crossover spectrum. We use the multiple image method to study the induced polarization effects and using spectral representation theory, an analytic expression for the DEP force is derived. Our results shows that the mutual polarization effects can change the crossover frequency at which the DEP force changes sign. The results are in agreement with recent experimental observations. Importantly, this approach goes beyond the standard theory and helps to clarify the important question of the underlying polarization mechanisms. The extension to dense systems and relation to electrorotation is discussed.

Astronomical phenomena: events with high impact factor in teaching optics and photonics

NASA Astrophysics Data System (ADS)

Curticapean, Dan

2014-07-01

Astronomical phenomena fascinate people from the very beginning of mankind up to today. They have a enthusiastic effect, especially on young people. Among the most amazing and well-known phenomena are the sun and moon eclipses. The impact factor of such events is very high, as they are being covered by mass media reports and the Internet, which provides encyclopedic content and discussion in social networks. The principal optics and photonics topics that can be included in such lessons originate from geometrical optics and the basic phenomena of reflection, refraction and total internal reflection. Lenses and lens systems up to astronomical instruments also have a good opportunity to be presented. The scientific content can be focused on geometrical optics but also diffractive and quantum optics can be incorporated successfully. The author will present how live streams of the moon eclipses can be used to captivate the interest of young listeners for optics and photonics. The gathered experience of the last two moon eclipses visible from Germany (on Dec, 21 2010 and Jun, 15 2011) will be considered. In an interactive broadcast we reached visitors from more than 135 countries.

Characterizing Air Temperature Changes in the Tarim Basin over 1960–2012

PubMed Central

Peng, Dongmei; Wang, Xiujun; Zhao, Chenyi; Wu, Xingren; Jiang, Fengqing; Chen, Pengxiang

2014-01-01

There has been evidence of warming rate varying largely over space and between seasons. However, little has been done to evaluate the spatial and temporal variability of air temperature in the Tarim Basin, northwest China. In this study, we collected daily air temperature from 19 meteorological stations for the period of 1960–2012, and analyzed annual mean temperature (AMT), the annual minimum (Tmin) and maximum temperature (Tmax), and mean temperatures of all twelve months and four seasons and their anomalies. Trend analyses, standard deviation of the detrended anomaly (SDDA) and correlations were carried out to characterize the spatial and temporal variability of various mean air temperatures. Our data showed that increasing trend was much greater in the Tmin (0.55°C/10a) than in the AMT (0.25°C/10a) and Tmax (0.12°C/10a), and the fluctuation followed the same order. There were large spatial variations in the increasing trends of both AMT (from −0.09 to 0.43 °C/10a) and Tmin (from 0.15 to 1.12°C/10a). Correlation analyses indicated that AMT had a significantly linear relationship with Tmin and the mean temperatures of four seasons. There were also pronounced changes in the monthly air temperature from November to March at decadal time scale. The seasonality (i.e., summer and winter difference) of air temperature was stronger during the period of 1960–1979 than over the recent three decades. Our preliminary analyses indicated that local environmental conditions (such as elevation) might be partly responsible for the spatial variability, and large scale climate phenomena might have influences on the temporal variability of air temperature in the Tarim Basin. In particular, there was a significant correlation between index of El Niño-Southern Oscillation (ENSO) and air temperature of May (P = 0.004), and between the index of Pacific Decadal Oscillation (PDO) and air temperature of July (P = 0.026) over the interannual to decadal time scales. PMID

Modeling some two-dimensional relativistic phenomena using an educational interactive graphics software

NASA Astrophysics Data System (ADS)

Sastry, G. P.; Ravuri, Tushar R.

1990-11-01

This paper describes several relativistic phenomena in two spatial dimensions that can be modeled using the collision program of Spacetime Software. These include the familiar aberration, the Doppler effect, the headlight effect, and the invariance of the speed of light in vacuum, in addition to the rather unfamiliar effects like the dragging of light in a moving medium, reflection at moving mirrors, Wigner rotation of noncommuting boosts, and relativistic rotation of shrinking and expanding rods. All these phenomena are exhibited by tracings of composite computer printouts of the collision movie. It is concluded that an interactive educational graphics software with pleasing visuals can have considerable investigative power packed within it.

Near Space Tracking of the EM Phenomena Associated with the Main Earthquakes

NASA Technical Reports Server (NTRS)

Ouzounov, Dimitar; Taylor, Patrick; Bryant, Nevin; Pulinets, Sergey; Liu, Jann-Yenq; Yang, Kwang-Su

2004-01-01

Searching for electromagnetic (EM) phenomena originating in the Earth's crust prior to major earthquakes (M>5) are the object of this exploratory study. We present the idea of a possible relationship between: (1) electro-chemical and thermodynamic processes in the Earth's crust and (2) ionic enhancement of the atmosphere/ionosphere with tectonic stress and earthquake activity. The major source of these signals are proposed to originate from electromagnetic phenomenon which are responsible for these observed pre-seismic processes, such as, enhanced IR emission, also born as thermal anomalies, generation of long wave radiation, light emission caused by ground-to-air electric discharges, Total Electron Content (TEC) ionospheric anomalies and ionospheric plasma variations. The source of these data will include: (i) ionospheric plasma perturbations data from the recently launched DEMETER mission and currently available TEC/GPS network data; (ii) geomagnetic data from ORSTED and CHAMP; (iii) Thermal infra-red (TIR) transients mapped by the polar orbiting (NOAA/AVHRR, MODIS) and (iv) geosynchronous weather satellites measurements of GOES, METEOSAT. This approach requires continues observations and data collecting, in addition to both ground and space based monitoring over selected regions in order to investigate the various techniques for recording possible anomalies. During the space campaign emphasis will be on IR emission, obtained from TIR (thermal infrared) satellites, that records land/sea surface temperature anomalies and changes in the plasma and total electron content (TEC) of the ionosphere that occur over areas of potential earthquake activity.

Advection fog formation and aerosols produced by combustion-originated air pollution

NASA Technical Reports Server (NTRS)

Hung, R. J.; Liaw, G. S.; Vaughan, O. H., Jr.

1980-01-01

The way in which pollutants produced by the photochemical reaction of NO(X) and SO(X) affect the quality of the human environment through such phenomena as the formation of advection fog is considered. These pollutants provide the major source of condensation nuclei for the formation of fog in highways, airports and seaports. Results based on the monodisperse, multicomponent aerosol model show that: (1) condensation nuclei can grow and form a dense fog without the air having attained supersaturation; (2) the mass concentration range for NO(X) is one-third that of SO(X); and (3) the greater the mass concentration, the particle concentration, and the radius of condensation nuclei, the denser the fog that is formed.

Period doubling and other nonlinear phenomena in volcanic earthquakes and tremor

USGS Publications Warehouse

Julian, B.R.

2000-01-01

Evidence of subharmonic period-doubling cascades has recently been recognized in seismograms of volcanic tremor from several volcanoes. This phenomenon occurs only in nonlinear systems, and is the commonest route by which such systems change from periodic to chaotic behavior. It is predicted to occur in a model of volcanic tremor excitation by flow-induced vibration, and it might well also occur in other volcano-seismic source process. If the possibility of period doubling is not taken into account in interpreting spectra of tremor and long-period earthquakes, then low-frequency "sub-harmonic" oscillations may be mis-identified as normal modes of a linear acoustic resonator, leading to errors of an order of magnitude or more in inferred magma-body dimensions. This example illustrates the importance of nonlinear phenomena in attempts to understand volcano-seismic phenomena physically. Linear systems are fundamentally incapable of causing earthquakes or exciting tremor, so nonlinearity is essential to any theory of volcano-seismic phenomena. Nonlinear processes are in many respects qualitatively different from linear ones. A few of their characteristics that might be relevant in volcanoes include the possibility: (1) that damping might increase, rather than decrease, oscillation frequencies; and (2) that these frequencies might be functions of the amplitude of oscillation, so that temporal variations in spectral peak frequencies might not be manifestations of changes of conditions within the magmatic system.

A tale of two congresses: the psychological study of psychical, occult, and religious phenomena, 1900-1909.

PubMed

Taves, Ann

2014-01-01

In so far as researchers viewed psychical, occult, and religious phenomena as both objectively verifiable and resistant to extant scientific explanations, their study posed thorny issues for experimental psychologists. Controversies over the study of psychical and occult phenomena at the Fourth Congress of International Psychology (Paris, 1900) and religious phenomena at the Sixth (Geneva, 1909) raise the question of why the latter was accepted as a legitimate object of study, whereas the former was not. Comparison of the Congresses suggests that those interested in the study of religion were willing to forego the quest for objective evidence and focus on experience, whereas those most invested in psychical research were not. The shift in focus did not overcome many of the methodological difficulties. Sub-specialization formalized distinctions between psychical, religious, and pathological phenomena; obscured similarities; and undercut the nascent comparative study of unusual experiences that had emerged at the early Congresses. © 2014 Wiley Periodicals, Inc.

33 CFR 334.1280 - Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force.

Code of Federal Regulations, 2012 CFR

2012-07-01

... weapon range, Alaskan Air Command, U.S. Air Force. 334.1280 Section 334.1280 Navigation and Navigable... REGULATIONS § 334.1280 Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force. (a... enforced by the Commander, Alaskan Air Command, U.S. Air Force, Seattle, Washington, or such agencies as he...

33 CFR 334.1280 - Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force.

Code of Federal Regulations, 2013 CFR

2013-07-01

... weapon range, Alaskan Air Command, U.S. Air Force. 334.1280 Section 334.1280 Navigation and Navigable... REGULATIONS § 334.1280 Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force. (a... enforced by the Commander, Alaskan Air Command, U.S. Air Force, Seattle, Washington, or such agencies as he...

33 CFR 334.1280 - Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force.

Code of Federal Regulations, 2014 CFR

2014-07-01

... weapon range, Alaskan Air Command, U.S. Air Force. 334.1280 Section 334.1280 Navigation and Navigable... REGULATIONS § 334.1280 Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force. (a... enforced by the Commander, Alaskan Air Command, U.S. Air Force, Seattle, Washington, or such agencies as he...

33 CFR 334.1280 - Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force.

Code of Federal Regulations, 2010 CFR

2010-07-01

... weapon range, Alaskan Air Command, U.S. Air Force. 334.1280 Section 334.1280 Navigation and Navigable... REGULATIONS § 334.1280 Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force. (a... enforced by the Commander, Alaskan Air Command, U.S. Air Force, Seattle, Washington, or such agencies as he...

33 CFR 334.1280 - Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force.

Code of Federal Regulations, 2011 CFR

2011-07-01

... weapon range, Alaskan Air Command, U.S. Air Force. 334.1280 Section 334.1280 Navigation and Navigable... REGULATIONS § 334.1280 Bristol Bay, Alaska; air-to-air weapon range, Alaskan Air Command, U.S. Air Force. (a... enforced by the Commander, Alaskan Air Command, U.S. Air Force, Seattle, Washington, or such agencies as he...

Surfactant-based critical phenomena in microgravity

NASA Technical Reports Server (NTRS)

Kaler, Eric W.; Paulaitis, Michael E.

1994-01-01

The objective of this research project is to characterize by experiment and theoretically both the kinetics of phase separation and the metastable structures produced during phase separation in a microgravity environment. The particular systems we are currently studying are mixtures of water, nonionic surfactants, and compressible supercritical fluids at temperatures and pressures where the coexisting liquid phases have equal densities (isopycnic phases). In this report, we describe experiments to locate equilibrium isopycnic phases and to determine the 'local' phase behavior and critical phenomena at nearby conditions of temperature, pressure, and composition. In addition, we report the results of preliminary small angle neutron scattering (SANS) experiments to characterize microstructures that exist in these mixtures at different fluid densities.

Advances in modelling of condensation phenomena

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

Liu, W.S.; Zaltsgendler, E.; Hanna, B.

1997-07-01

The physical parameters in the modelling of condensation phenomena in the CANDU reactor system codes are discussed. The experimental programs used for thermal-hydraulic code validation in the Canadian nuclear industry are briefly described. The modelling of vapour generation and in particular condensation plays a key role in modelling of postulated reactor transients. The condensation models adopted in the current state-of-the-art two-fluid CANDU reactor thermal-hydraulic system codes (CATHENA and TUF) are described. As examples of the modelling challenges faced, the simulation of a cold water injection experiment by CATHENA and the simulation of a condensation induced water hammer experiment by TUFmore » are described.« less

Physical Phenomena in Containerless Glass Processing

NASA Technical Reports Server (NTRS)

Subramanian, R. S.; Cole, R.

1985-01-01

An investigation into the various physical phenomena of importance in the space experiments is under way. Theoretical models of thermocapillary flow in drops, thermal migration of bubbles and droplets, the motion of bubbles inside drops, and the migration of bubbles in rotating liquid bodies are being developed. Experiments were conducted on the migration of bubbles and droplets to the axis of a rotating liquid body, and the rise of bubbles in molten glass. Also, experiments on thermocapillary motion in silicone oils as well as glass melts were performed. Experiments are currently being conducted on the migration of bubbles in a thermal gradient, and on their motion inside unconstrained liquid drops in a rotating liquid.

Arcjet Cathode Phenomena

NASA Technical Reports Server (NTRS)

Curran, Francis M.; Haag, Thomas W.; Raquet, John F.

1989-01-01

Cathode tips made from a number of different materials were tested in a modular arcjet thruster in order to examine cathode phenomena. Periodic disassembly and examination, along with the data collected during testing, indicated that all of the tungsten-based materials behaved similarly despite the fact that in one of these samples the percentage of thorium oxide was doubled and another was 25 percent rhenium. The mass loss rate from a 2 percent thoriated rhenium cathode was found to be an order of magnitude greater than that observed using 2 percent thoriated tungsten. Detailed analysis of one of these cathode tips showed that the molten crater contained pure tungsten to a depth of about 150 microns. Problems with thermal stress cracking were encountered in the testing of a hafnium carbide tip. Post test analysis showed that the active area of the tip had chemically reacted with the propellant. A 100 hour continuous test was run at about 1 kW. Post test analysis revealed no dendrite formation, such as observed in a 30 kW arcjet lifetest, near the cathode crater. The cathodes from both this test and a previously run 1000 hour cycled test displayed nearly identical arc craters. Data and calculations indicate that the mass losses observed in testing can be explained by evaporation.

Arcjet cathode phenomena

NASA Technical Reports Server (NTRS)

Curran, Francis M.; Haag, Thomas W.; Raquet, John F.

1989-01-01

Cathode tips made from a number of different materials were tested in a modular arcjet thruster in order to examine cathode phenomena. Periodic disassembly and examination, along with the data collected during testing, indicated that all of the tungsten-based materials behaved similarly despite the fact that in one of these samples the percentage of thorium oxide was doubled and another was 25 percent rhenium. The mass loss rate from a 2 percent thoriated rhenium cathode was found to be an order of magnitude greater than that observed using 2 percent thoriated tungsten. Detailed analysis of one of these cathode tips showed that the molten crater contained pure tungsten to a depth of about 150 microns. Problems with thermal stress cracking were encountered in the testing of a hafnium carbide tip. Post test analysis showed that the active area of the tip had chemically reacted with the propellant. A 100 hour continuous test was run at about 1 kW. Post test analysis revealed no dendrite formation, such as observed in a 30 kW arcjet lifetest, near the cathode crater. The cathodes from both this test and a previously run 1000 hour cycled test displayed nearly identical arc craters. Data and calculations indicate that the mass losses observed in testing can be explained by evaporation.

Rapid Diffusion and Nanosegregation of Hydrogen in Magnesium Alloys from Exposure to Water.

PubMed

Brady, Michael P; Ievlev, Anton V; Fayek, Mostafa; Leonard, Donovan N; Frith, Matthew G; Meyer, Harry M; Ramirez-Cuesta, Anibal J; Daemen, Luke L; Cheng, Yongqiang; Guo, Wei; Poplawsky, Jonathan D; Ovchinnikova, Olga S; Thomson, Jeffrey; Anovitz, Lawrence M; Rother, Gernot; Shin, Dongwon; Song, Guang-Ling; Davis, Bruce

2017-11-01

Hydrogen gas is formed when Mg corrodes in water; however, the manner and extent to which the hydrogen may also enter the Mg metal is poorly understood. Such knowledge is critical as stress corrosion cracking (SCC)/embrittlement phenomena limit many otherwise promising structural and functional uses of Mg. Here, we report via D 2 O/D isotopic tracer and H 2 O exposures with characterization by secondary ion mass spectrometry, inelastic neutron scattering vibrational spectrometry, electron microscopy, and atom probe tomography techniques direct evidence that hydrogen rapidly penetrated tens of micrometers into Mg metal after only 4 h of exposure to water at room temperature. Further, technologically important microalloying additions of <1 wt % Zr and Nd used to improve the manufacturability and mechanical properties of Mg significantly increased the extent of hydrogen ingress, whereas Al additions in the 2-3 wt % range did not. Segregation of hydrogen species was observed at regions of high Mg/Zr/Nd nanoprecipitate density and at Mg(Zr) metastable solid solution microstructural features. We also report evidence that this ingressed hydrogen was unexpectedly present in the alloy as nanoconfined, molecular H 2 . These new insights provide a basis for strategies to design Mg alloys to resist SCC in aqueous environments as well as potentially impact functional uses such as hydrogen storage where increased hydrogen uptake is desired.

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

Brady, Michael P.; Ievlev, Anton V.; Fayek, Mostafa

Hydrogen gas is formed when Mg corrodes in water; however, the manner and extent to which the hydrogen may also enter the Mg metal is poorly understood. Such knowledge is critical as stress corrosion cracking (SCC)/embrittlement phenomena limit many otherwise promising structural and functional uses of Mg. Here, we report via D 2O/D isotopic tracer and H 2O exposures with characterization by secondary ion mass spectrometry, inelastic neutron scattering vibrational spectrometry, electron microscopy, and atom probe tomography techniques direct evidence that hydrogen rapidly penetrated tens of micrometers into Mg metal after only 4 h of exposure to water at roommore » temperature. Further, technologically important microalloying additions of <1 wt % Zr and Nd used to improve the manufacturability and mechanical properties of Mg significantly increased the extent of hydrogen ingress, whereas Al additions in the 2–3 wt % range did not. Segregation of hydrogen species was observed at regions of high Mg/Zr/Nd nanoprecipitate density and at Mg(Zr) metastable solid solution microstructural features. We also report evidence that this ingressed hydrogen was unexpectedly present in the alloy as nanoconfined, molecular H 2. These new insights provide a basis for strategies to design Mg alloys to resist SCC in aqueous environments as well as potentially impact functional uses such as hydrogen storage where increased hydrogen uptake is desired.« less

Rapid Diffusion and Nanosegregation of Hydrogen in Magnesium Alloys from Exposure to Water

DOE PAGES

Brady, Michael P.; Ievlev, Anton V.; Fayek, Mostafa; ...

2017-10-10

Hydrogen gas is formed when Mg corrodes in water; however, the manner and extent to which the hydrogen may also enter the Mg metal is poorly understood. Such knowledge is critical as stress corrosion cracking (SCC)/embrittlement phenomena limit many otherwise promising structural and functional uses of Mg. Here, we report via D 2O/D isotopic tracer and H 2O exposures with characterization by secondary ion mass spectrometry, inelastic neutron scattering vibrational spectrometry, electron microscopy, and atom probe tomography techniques direct evidence that hydrogen rapidly penetrated tens of micrometers into Mg metal after only 4 h of exposure to water at roommore » temperature. Further, technologically important microalloying additions of <1 wt % Zr and Nd used to improve the manufacturability and mechanical properties of Mg significantly increased the extent of hydrogen ingress, whereas Al additions in the 2–3 wt % range did not. Segregation of hydrogen species was observed at regions of high Mg/Zr/Nd nanoprecipitate density and at Mg(Zr) metastable solid solution microstructural features. We also report evidence that this ingressed hydrogen was unexpectedly present in the alloy as nanoconfined, molecular H 2. These new insights provide a basis for strategies to design Mg alloys to resist SCC in aqueous environments as well as potentially impact functional uses such as hydrogen storage where increased hydrogen uptake is desired.« less

Noncontact temperature measurements in the microgravity fluids and transport phenomena discipline

NASA Technical Reports Server (NTRS)

Salzman, Jack

1988-01-01

The program of activities within the Microgravity Fluids and Transport Phenomena Discipline has been structured to enable the systematic pursuit of an increased understanding of low gravity fluid behavior/phenomena in a way which ensures that the results are appropriate to the widest range of applications. This structure is discussed and an overview of some of the activities which are underway is given. Of significance is the fact that in the majority of the current and planned activities, the measurement and, or control of the fluid temperature is a key experiment requirement. In addition, many of the experiments require that the temperature measurement be nonintrusive. A description of these requirements together with the current techniques which are being employed or under study to make these measurements is also discussed.

The numerical modelling of mixing phenomena of nanofluids in passive micromixers

NASA Astrophysics Data System (ADS)

Milotin, R.; Lelea, D.

2018-01-01

The paper deals with the rapid mixing phenomena in micro-mixing devices with four tangential injections and converging tube, considering nanoparticles and water as the base fluid. Several parameters like Reynolds number (Re = 6 - 284) or fluid temperature are considered in order to optimize the process and obtain fundamental insight in mixing phenomena. The set of partial differential equations is considered based on conservation of momentum and species. Commercial package software Ansys-Fluent is used for solution of differential equations, based on a finite volume method. The results reveal that mixing index and mixing process is strongly dependent both on Reynolds number and heat flux. Moreover there is a certain Reynolds number when flow instabilities are generated that intensify the mixing process due to the tangential injections of the fluids.

Acoustic emission signal processing technique to characterize reactor in-pile phenomena

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

Agarwal, Vivek, E-mail: vivek.agarwal@inl.gov; Tawfik, Magdy S., E-mail: magdy.tawfik@inl.gov; Smith, James A., E-mail: james.smith@inl.gov

2015-03-31

Existing and developing advanced sensor technologies and instrumentation will allow non-intrusive in-pile measurement of temperature, extension, and fission gases when coupled with advanced signal processing algorithms. The transmitted measured sensor signals from inside to the outside of containment structure are corrupted by noise and are attenuated, thereby reducing the signal strength and the signal-to-noise ratio. Identification and extraction of actual signal (representative of an in-pile phenomenon) is a challenging and complicated process. In the paper, empirical mode decomposition technique is utilized to reconstruct actual sensor signal by partially combining intrinsic mode functions. Reconstructed signal will correspond to phenomena and/or failuremore » modes occurring inside the reactor. In addition, it allows accurate non-intrusive monitoring and trending of in-pile phenomena.« less

Technical basis, supporting information, and strategy for development and implementation of DOE policy for natural phenomena hazards

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

Murray, R.C.

1991-09-01

Policy for addressing natural phenomenon comprises a hierarchy of interrelated documents. The top level of policy is contained in the code of Federal Regulations which establishes the framework and intent to ensure overall safety of DOE facilities when subjected to the effects of natural phenomena. The natural phenomena to be considered include earthquakes and tsunami, winds, hurricanes and tornadoes, floods, volcano effects and seiches. Natural phenomena criteria have been established for design of new facilities; evaluation of existing facilities; additions, modifications, and upgrades to existing facilities; and evaluation criteria for new or existing sites. Steps needed to implement these fourmore » general criteria are described. The intent of these criteria is to identify WHAT needs to be done to ensure adequate protection from natural phenomena. The commentary provides discussion of WHY this is needed for DOE facilities within the complex. Implementing procedures identifying HOW to carry out these criteria are next identified. Finally, short and long term tasks needed to identify the implementing procedure are tabulated. There is an overall need for consistency throughout the DOE complex related to natural phenomena including consistent terminology, policy, and implementation. 1 fig, 6 tabs.« less

Using LabVIEW for Applying Mathematical Models in Representing Phenomena

ERIC Educational Resources Information Center

Faraco, G.; Gabriele, L.

2007-01-01

Simulations make it possible to explore physical and biological phenomena, where conducting the real experiment is impracticable or difficult. The implementation of a software program describing and simulating a given physical situation encourages the understanding of a phenomenon itself. Fifty-nine students, enrolled at the Mathematical Methods…

Linguistic Studies on English Pronominalization: Syntactic, Discourse and Pragmatic Phenomena.

ERIC Educational Resources Information Center

Barnitz, John G.

To integrate many of the theoretical linguistic studies examining pronoun reference, this paper focuses on tracing the shift from purely transformational syntactic studies of intrasentential phenomena to the wider orientations of discourse and pragmatic studies. The first section describes the classic studies of pronominalization within the…

The ultrastructure of book lung development in the bark scorpion Centruroides gracilis (Scorpiones: Buthidae)

PubMed Central

2011-01-01

Background Near the end of the nineteenth century the hypothesis was presented for the homology of book lungs in arachnids and book gills in the horseshoe crab. Early studies with the light microscope showed that book gill lamellae are formed by outgrowth and possibly some invagination (infolding) of hypodermis (epithelium) from the posterior surface of opisthosomal limb buds. Scorpion book lungs are formed near the bilateral sites of earlier limb buds. Hypodermal invaginations in the ventral opisthosoma result in spiracles and sac-like cavities (atria). In early histological sections of embryo book lungs, widening of the atrial entrance of some lamellae (air channels, air sacs, saccules) was interpreted as an indication of invagination as hypothesized for book gill lamellae. The hypodermal infolding was thought to produce the many rows of lamellar precursor cells anterior to the atrium. The ultrastructure of scorpion book lung development is compared herein with earlier investigations of book gill formation. Results In scorpion embryos, there is ingression (inward migration) of atrial hypodermal cells rather than invagination or infolding of the atrial hypodermal layer. The ingressing cells proliferate and align in rows anterior to the atrium. Their apical-basal polarity results in primordial air channels among double rows of cells. The cuticular walls of the air channels are produced by secretion from the apical surfaces of the aligned cells. Since the precursor cells are in rows, their secreted product is also in rows (i.e., primordial air channels, saccules). For each double row of cells, their opposed basal surfaces are gradually separated by a hemolymph channel of increasing width. Conclusions The results from this and earlier studies show there are differences and similarities in the formation of book lung and book gill lamellae. The homology hypothesis for these respiratory organs is thus supported or not supported depending on which developmental features

Agent-based spin model for financial markets on complex networks: Emergence of two-phase phenomena

NASA Astrophysics Data System (ADS)

Kim, Yup; Kim, Hong-Joo; Yook, Soon-Hyung

2008-09-01

We study a microscopic model for financial markets on complex networks, motivated by the dynamics of agents and their structure of interaction. The model consists of interacting agents (spins) with local ferromagnetic coupling and global antiferromagnetic coupling. In order to incorporate more realistic situations, we also introduce an external field which changes in time. From numerical simulations, we find that the model shows two-phase phenomena. When the local ferromagnetic interaction is balanced with the global antiferromagnetic interaction, the resulting return distribution satisfies a power law having a single peak at zero values of return, which corresponds to the market equilibrium phase. On the other hand, if local ferromagnetic interaction is dominant, then the return distribution becomes double peaked at nonzero values of return, which characterizes the out-of-equilibrium phase. On random networks, the crossover between two phases comes from the competition between two different interactions. However, on scale-free networks, not only the competition between the different interactions but also the heterogeneity of underlying topology causes the two-phase phenomena. Possible relationships between the critical phenomena of spin system and the two-phase phenomena are discussed.

The role of perspective taking in how children connect reference frames when explaining astronomical phenomena

NASA Astrophysics Data System (ADS)

Plummer, Julia D.; Bower, Corinne A.; Liben, Lynn S.

2016-02-01

This study investigates the role of perspective-taking skills in how children explain spatially complex astronomical phenomena. Explaining many astronomical phenomena, especially those studied in elementary and middle school, requires shifting between an Earth-based description of the phenomena and a space-based reference frame. We studied 7- to 9-year-old children (N = 15) to (a) develop a method for capturing how children make connections between reference frames and to (b) explore connections between perspective-taking skill and the nature of children's explanations. Children's explanations for the apparent motion of the Sun and stars and for seasonal changes in constellations were coded for accuracy of explanation, connection between frames of reference, and use of gesture. Children with higher spatial perspective-taking skills made more explicit connections between reference frames and used certain gesture-types more frequently, although this pattern was evident for only some phenomena. Findings suggest that children - particularly those with lower perspective-taking skills - may need additional support in learning to explicitly connect reference frames in astronomy. Understanding spatial thinking among children who successfully made explicit connections between reference frames in their explanations could be a starting point for future instruction in this domain.

Just the two of us: misalignment of theory and methods in examining dyadic phenomena.

PubMed

Krasikova, Dina V; LeBreton, James M

2012-07-01

Many organizational phenomena such as leader-member exchange, mentoring, coaching, interpersonal conflict and cooperation, negotiation, performance appraisal, and the employment interview involve inherently dyadic relationships and interactions. Even when theories explicitly acknowledge the dyadic nature of such phenomena, it is not uncommon to observe a disconnection or misalignment between the level of theory and method. Our purpose in the current paper is to discuss how organizational scholars might better align these components of their research endeavors. We discuss how recent developments involving the actor-partner interdependence model (APIM) and reciprocal one-with-many (OWM) models are applicable to studying dyadic phenomena in organizations. The emphasis is on preanalytic considerations associated with collecting and organizing reciprocal dyadic data, types of research questions that APIM and reciprocal OWM models can help answer, and specific analytic techniques involved in testing dyadic hypotheses. (PsycINFO Database Record (c) 2012 APA, all rights reserved).

High spatial resolution measurements of ram accelerator gas dynamic phenomena

NASA Technical Reports Server (NTRS)

Hinkey, J. B.; Burnham, E. A.; Bruckner, A. P.

1992-01-01

High spatial resolution experimental tube wall pressure measurements of ram accelerator gas dynamic phenomena are presented. The projectile resembles the centerbody of a ramjet and travels supersonically through a tube filled with a combustible gaseous mixture, with the tube acting as the outer cowling. Pressure data are recorded as the projectile passes by sensors mounted in the tube wall at various locations along the tube. Data obtained by using a special highly instrumented section of tube has allowed the recording of gas dynamic phenomena with a spatial resolution on the order of one tenth the projectile length. High spatial resolution tube wall pressure data from the three regimes of propulsion studied to date (subdetonative, transdetonative, and superdetonative) are presented and reveal the 3D character of the flowfield induced by projectile fins and the canting of the projectile body relative to the tube wall. Also presented for comparison to the experimental data are calculations made with an inviscid, 3D CFD code.

Brain structural correlates of sensory phenomena in patients with obsessive–compulsive disorder

PubMed Central

Subirà, Marta; Sato, João R.; Alonso, Pino; do Rosário, Maria C.; Segalàs, Cinto; Batistuzzo, Marcelo C.; Real, Eva; Lopes, Antonio C.; Cerrillo, Ester; Diniz, Juliana B.; Pujol, Jesús; Assis, Rachel O.; Menchón, José M.; Shavitt, Roseli G.; Busatto, Geraldo F.; Cardoner, Narcís; Miguel, Euripedes C.; Hoexter, Marcelo Q.; Soriano-Mas, Carles

2015-01-01

Background Sensory phenomena (SP) are uncomfortable feelings, including bodily sensations, sense of inner tension, “just-right” perceptions, feelings of incompleteness, or “urge-only” phenomena, which have been described to precede, trigger or accompany repetitive behaviours in individuals with obsessive–compulsive disorder (OCD). Sensory phenomena are also observed in individuals with tic disorders, and previous research suggests that sensorimotor cortex abnormalities underpin the presence of SP in such patients. However, to our knowledge, no studies have assessed the neural correlates of SP in patients with OCD. Methods We assessed the presence of SP using the University of São Paulo Sensory Phenomena Scale in patients with OCD and healthy controls from specialized units in São Paulo, Brazil, and Barcelona, Spain. All participants underwent a structural magnetic resonance examination, and brain images were examined using DARTEL voxel-based morphometry. We evaluated grey matter volume differences between patients with and without SP and healthy controls within the sensorimotor and premotor cortices. Results We included 106 patients with OCD and 87 controls in our study. Patients with SP (67% of the sample) showed grey matter volume increases in the left sensorimotor cortex in comparison to patients without SP and bilateral sensorimotor cortex grey matter volume increases in comparison to controls. No differences were observed between patients without SP and controls. Limitations Most patients were medicated. Participant recruitment and image acquisition were performed in 2 different centres. Conclusion We have identified a structural correlate of SP in patients with OCD involving grey matter volume increases within the sensorimotor cortex; this finding is in agreement with those of tic disorder studies showing that abnormal activity and volume increases within this region are associated with the urges preceding tic onset. PMID:25652753

New phenomena in non-equilibrium quantum physics

NASA Astrophysics Data System (ADS)

Kitagawa, Takuya

From its beginning in the early 20th century, quantum theory has become progressively more important especially due to its contributions to the development of technologies. Quantum mechanics is crucial for current technology such as semiconductors, and also holds promise for future technologies such as superconductors and quantum computing. Despite of the success of quantum theory, its applications have been mostly limited to equilibrium or static systems due to 1. lack of experimental controllability of non-equilibrium quantum systems 2. lack of theoretical frameworks to understand non-equilibrium dynamics. Consequently, physicists have not yet discovered too many interesting phenomena in non-equilibrium quantum systems from both theoretical and experimental point of view and thus, non-equilibrium quantum physics did not attract too much attentions. The situation has recently changed due to the rapid development of experimental techniques in condensed matter as well as cold atom systems, which now enables a better control of non-equilibrium quantum systems. Motivated by this experimental progress, we constructed theoretical frameworks to study three different non-equilibrium regimes of transient dynamics, steady states and periodically drives. These frameworks provide new perspectives for dynamical quantum process, and help to discover new phenomena in these systems. In this thesis, we describe these frameworks through explicit examples and demonstrate their versatility. Some of these theoretical proposals have been realized in experiments, confirming the applicability of the theories to realistic experimental situations. These studies have led to not only the improved fundamental understanding of non-equilibrium processes in quantum systems, but also suggested entirely different venues for developing quantum technologies.

Meteorological phenomena in Western classical orchestral music

NASA Astrophysics Data System (ADS)

Williams, P. D.; Aplin, K. L.

2012-12-01

The creative output of composers, writers, and artists is often influenced by their surroundings. To give a literary example, it has been claimed recently that some of the characters in Oliver Twist and A Christmas Carol were based on real-life people who lived near Charles Dickens in London. Of course, an important part of what we see and hear is not only the people with whom we interact, but also our geophysical surroundings. Of all the geophysical phenomena to influence us, the weather is arguably the most significant, because we are exposed to it directly and daily. The weather was a great source of inspiration for Monet, Constable, and Turner, who are known for their scientifically accurate paintings of the skies. But to what extent does weather inspire composers? The authors of this presentation, who are atmospheric scientists by day but amateur classical musicians by night, have been contemplating this question. We have built a systematic musical database, which has allowed us to catalogue and analyze the frequencies with which weather is depicted in a sample of classical orchestral music. The depictions vary from explicit mimicry using traditional and specialized orchestral instruments, through to subtle suggestions. We have found that composers are generally influenced by their own environment in the type of weather they choose to represent. As befits the national stereotype, British composers seem disproportionately keen to depict the UK's variable weather patterns and stormy coastline. Reference: Aplin KL and Williams PD (2011) Meteorological phenomena in Western classical orchestral music. Weather, 66(11), pp 300-306. doi:10.1002/wea.765

Nonlinear Phenomena in Electromagnetic and Acoustic Wave Propagation.

DTIC Science & Technology

1984-04-01

W~ . f. W. ~.. ~ . . W-71 40. R. Burridge Poroelasticity equations derived from J. B. Keller microstructure Pub: J. Acoust . Soc. Am., 70, 1140...Pub: Coin. Pure Appl. Math., 36, 547-569, 1983. 91. J. B. Keller Asymptotic analysis of a viscous Cochlear model 1. C. ou Sub: J. Acoust . Soc. Am. 92...34RD-R49 螜 NONLINEAR PHENOMENA IN ELECTROMAGNETIC AND ACOUSTIC /1 NAVE PROPAORTION(U) STANFORD UNIV CA DEPT OF MATHEMATICS J B KELLER APR 84 ARO

STS-135 crew during Ingress/Egress Timeline training in building 9NW space station mockups

NASA Image and Video Library

2011-04-29

JSC2011-E-043875 (29 April 2011) --- NASA astronaut Rex Walheim, STS-135 mission specialist, participates in an EVA Thermal Protection System (TPS) overview training session in the TPS/Precision Air Bearing Facility in the Space Vehicle Mock-up Facility at NASA's Johnson Space Center. Photo credit: NASA

Prebreakdown phenomena and formation process of the glow discharge in low-pressure Ar gas

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

Hosokawa, Tatsuzo; Goto, Kazuhiro; Ohuchi, Mikio

2001-06-01

The prebreakdown phenomena and the formation process of the glow discharge in a low-pressure Ar gas were investigated under a uniform field gap. Prebreakdown phenomena were observed for 0.5Torrcm{le}pd{le}2Torrcm (where p is pressure, d the gap distance) in Ar gas under conditions of a slowly increasing voltage. It was observed that the prebreakdown phenomena formed pulse discharges up to the transition to the glow discharge. The amplitudes of the photon and current pulses due to the pulse discharge increased with time, and then decreased as soon as the transition to a steady glow discharge occurred. When the overvoltage or externalmore » series resistance was increased, the pulse amplitudes increased with the applied voltage and decreased with the resistance. The characteristics of the prebreakdown phenomena were changed by the shape of the electrodes. The formation mechanism of the glow discharge can be qualitatively explained by that of the streamer in a high-pressure discharge. The transient glow discharge was observed, and its duration increased with an increase in resistance. The instability of the glow discharge was controlled by three factors, namely, Kaufmann{close_quote}s criterion, the Child{endash}Langmuir law, and the density balance between the production and removal rates of electrons. {copyright} 2001 American Institute of Physics.« less

Theory and experimental evidence of phonon domains and their roles in pre-martensitic phenomena

NASA Astrophysics Data System (ADS)

Jin, Yongmei M.; Wang, Yu U.; Ren, Yang

2015-12-01

Pre-martensitic phenomena, also called martensite precursor effects, have been known for decades while yet remain outstanding issues. This paper addresses pre-martensitic phenomena from new theoretical and experimental perspectives. A statistical mechanics-based Grüneisen-type phonon theory is developed. On the basis of deformation-dependent incompletely softened low-energy phonons, the theory predicts a lattice instability and pre-martensitic transition into elastic-phonon domains via 'phonon spinodal decomposition.' The phase transition lifts phonon degeneracy in cubic crystal and has a nature of phonon pseudo-Jahn-Teller lattice instability. The theory and notion of phonon domains consistently explain the ubiquitous pre-martensitic anomalies as natural consequences of incomplete phonon softening. The phonon domains are characterised by broken dynamic symmetry of lattice vibrations and deform through internal phonon relaxation in response to stress (a particular case of Le Chatelier's principle), leading to previously unexplored new domain phenomenon. Experimental evidence of phonon domains is obtained by in situ three-dimensional phonon diffuse scattering and Bragg reflection using high-energy synchrotron X-ray single-crystal diffraction, which observes exotic domain phenomenon fundamentally different from usual ferroelastic domain switching phenomenon. In light of the theory and experimental evidence of phonon domains and their roles in pre-martensitic phenomena, currently existing alternative opinions on martensitic precursor phenomena are revisited.

Exotic Phenomena in Quantum limit in nodal-line semimetal ZrSiS

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

Hu, Jin; Liu, Jinyu; Mao, Zhiqiang

2017-03-01

In quantum limit, all carriers condense to the lowest Landau level, leading to possible exotic quantum phenomena such as Lifshitz transition and density waves. Usually, quantum limit is not easily achieved due to relatively large Fermi surface in metals. Fortunately, the nodal-line semimetal ZrSiS possesses a very small Fermi pocket with a characteristic quantum oscillation frequency of 8.4T, which represents the 2D Dirac states protected by non-symmorphic symmetry. The quantum limit of such Dirac bands can be reached in moderate magnetic field ~25T, indicating that ZrSiS could be a nice platform to explore the novel quantum phenomena of Dirac fermionsmore » in quantum limit.« less

The Role of Thermal Properties in Periodic Time-Varying Phenomena

ERIC Educational Resources Information Center

Marin, E.

2007-01-01

The role played by physical parameters governing the transport of heat in periodical time-varying phenomena within solids is discussed. Starting with a brief look at the conduction heat transport mechanism, the equations governing heat conduction under static, stationary and non-stationary conditions, and the physical parameters involved, are…

Collective phenomena in crowds—Where pedestrian dynamics need social psychology

PubMed Central

2017-01-01

This article is on collective phenomena in pedestrian dynamics during the assembling and dispersal of gatherings. To date pedestrian dynamics have been primarily studied in the natural and engineering sciences. Pedestrians are analyzed and modeled as driven particles revealing self-organizing phenomena and complex transport characteristics. However, pedestrians in crowds also behave as living beings according to stimulus-response mechanisms or act as human subjects on the basis of social norms, social identities or strategies. To show where pedestrian dynamics need social psychology in addition to the natural sciences we propose the application of three categories–phenomena, behavior and action. They permit a clear discrimination between situations in which minimal models from the natural sciences are appropriate and those in which sociological and psychological concepts are needed. To demonstrate the necessity of this framework, an experiment in which a large group of people (n = 270) enters a concert hall through two different spatial barrier structures is analyzed. These two structures correspond to everyday situations such as boarding trains and access to immigration desks. Methods from the natural and social sciences are applied. Firstly, physical measurements show the influence of the spatial structure on the dynamics of the entrance procedure. Density, waiting time and speed of progress show large variations. Secondly, a questionnaire study (n = 60) reveals how people perceive and evaluate these entrance situations. Markedly different expectations, social norms and strategies are associated with the two spatial structures. The results from the questionnaire study do not always conform to objective physical measures, indicating the limitations of models which are based on objective physical measures alone and which neglect subjective perspectives. PMID:28591142

Collective phenomena in crowds-Where pedestrian dynamics need social psychology.

PubMed

Sieben, Anna; Schumann, Jette; Seyfried, Armin

2017-01-01

This article is on collective phenomena in pedestrian dynamics during the assembling and dispersal of gatherings. To date pedestrian dynamics have been primarily studied in the natural and engineering sciences. Pedestrians are analyzed and modeled as driven particles revealing self-organizing phenomena and complex transport characteristics. However, pedestrians in crowds also behave as living beings according to stimulus-response mechanisms or act as human subjects on the basis of social norms, social identities or strategies. To show where pedestrian dynamics need social psychology in addition to the natural sciences we propose the application of three categories-phenomena, behavior and action. They permit a clear discrimination between situations in which minimal models from the natural sciences are appropriate and those in which sociological and psychological concepts are needed. To demonstrate the necessity of this framework, an experiment in which a large group of people (n = 270) enters a concert hall through two different spatial barrier structures is analyzed. These two structures correspond to everyday situations such as boarding trains and access to immigration desks. Methods from the natural and social sciences are applied. Firstly, physical measurements show the influence of the spatial structure on the dynamics of the entrance procedure. Density, waiting time and speed of progress show large variations. Secondly, a questionnaire study (n = 60) reveals how people perceive and evaluate these entrance situations. Markedly different expectations, social norms and strategies are associated with the two spatial structures. The results from the questionnaire study do not always conform to objective physical measures, indicating the limitations of models which are based on objective physical measures alone and which neglect subjective perspectives.

Multiscale Modeling of Mesoscale and Interfacial Phenomena

NASA Astrophysics Data System (ADS)

Petsev, Nikolai Dimitrov

With rapidly emerging technologies that feature interfaces modified at the nanoscale, traditional macroscopic models are pushed to their limits to explain phenomena where molecular processes can play a key role. Often, such problems appear to defy explanation when treated with coarse-grained continuum models alone, yet remain prohibitively expensive from a molecular simulation perspective. A prominent example is surface nanobubbles: nanoscopic gaseous domains typically found on hydrophobic surfaces that have puzzled researchers for over two decades due to their unusually long lifetimes. We show how an entirely macroscopic, non-equilibrium model explains many of their anomalous properties, including their stability and abnormally small gas-side contact angles. From this purely transport perspective, we investigate how factors such as temperature and saturation affect nanobubbles, providing numerous experimentally testable predictions. However, recent work also emphasizes the relevance of molecular-scale phenomena that cannot be described in terms of bulk phases or pristine interfaces. This is true for nanobubbles as well, whose nanoscale heights may require molecular detail to capture the relevant physics, in particular near the bubble three-phase contact line. Therefore, there is a clear need for general ways to link molecular granularity and behavior with large-scale continuum models in the treatment of many interfacial problems. In light of this, we have developed a general set of simulation strategies that couple mesoscale particle-based continuum models to molecular regions simulated through conventional molecular dynamics (MD). In addition, we derived a transport model for binary mixtures that opens the possibility for a wide range of applications in biological and drug delivery problems, and is readily reconciled with our hybrid MD-continuum techniques. Approaches that couple multiple length scales for fluid mixtures are largely absent in the literature, and

Quantifying energy and mass transfer in crop canopies: sensors for measurement of temperature and air velocity

NASA Technical Reports Server (NTRS)

Bugbee, B.; Monje, O.; Tanner, B.

1996-01-01

Here we report on the in situ performance of inexpensive, miniature sensors that have increased our ability to measure mass and energy fluxes from plant canopies in controlled environments: 1. Surface temperature. Canopy temperature measurements indicate changes in stomatal aperture and thus latent and sensible heat fluxes. Infrared transducers from two manufacturers (Exergen Corporation, Newton, MA; and Everest Interscience, Tucson, AZ, USA) have recently become available. Transducer accuracy matched that of a more expensive hand-held infrared thermometer. 2. Air velocity varies above and within plant canopies and is an important component in mass and energy transfer models. We tested commercially-available needle, heat-transfer anemometers (1 x 50 mm cylinder) that consist of a fine-wire thermocouple and a heater inside a hypodermic needle. The needle is heated and wind speed determined from the temperature rise above ambient. These sensors are particularly useful in measuring the low wind speeds found within plant canopies. 3. Accurate measurements of air temperature adjacent to plant leaves facilitates transport phenomena modeling. We quantified the effect of radiation and air velocity on temperature rise in thermocouples from 10 to 500 micrometers. At high radiation loads and low wind speeds, temperature errors were as large as 7 degrees C above air temperature.

Towards an understanding of flows in avalanche transport phenomena

NASA Astrophysics Data System (ADS)

Jin, Suying; Ramadan, Nikolas; van Compernolle, Bart; Poulos, Matt J.; Morales, George J.

2017-10-01

Recent heat transport experiments conducted in the Large Plasma Device (LAPD) at UCLA, studying avalanche phenomena at steep cross-magnetic field pressure gradients, suggest that flows play a critical role in the evolution of transport phenomena, motivating further characterization. A ring shaped electron beam source injects sub-ionization energy electrons along the strong background magnetic field within a larger quiescent plasma, creating a hollow, high pressure filament. Two distinct regimes are observed as the density decays; the first characterized by multiple small avalanches producing sudden relaxations of the pressure profile which then recovers under continued heating, and the second signaled by a permanent collapse of the density profile after a global avalanche event, then dominated by drift-Alfven waves. The source is modified from previous experiments to gain active control of the flows by controlling the bias between the emitting ring and surrounding carbon masks. The results of flow measurements obtained using a Mach probe and Langmuir/emissive probe are here presented and compared. An analytical model for the behavior of the electron beam source is also in development. Sponsored by NSF Grant 1619505 and by DOE/NSF at BaPSF.

Nuclear disarmament verification via resonant phenomena.

PubMed

Hecla, Jake J; Danagoulian, Areg

2018-03-28

Nuclear disarmament treaties are not sufficient in and of themselves to neutralize the existential threat of the nuclear weapons. Technologies are necessary for verifying the authenticity of the nuclear warheads undergoing dismantlement before counting them toward a treaty partner's obligation. Here we present a concept that leverages isotope-specific nuclear resonance phenomena to authenticate a warhead's fissile components by comparing them to a previously authenticated template. All information is encrypted in the physical domain in a manner that amounts to a physical zero-knowledge proof system. Using Monte Carlo simulations, the system is shown to reveal no isotopic or geometric information about the weapon, while readily detecting hoaxing attempts. This nuclear technique can dramatically increase the reach and trustworthiness of future nuclear disarmament treaties.

Numerical simulation of severe convective phenomena over Croatian and Hungarian territory

NASA Astrophysics Data System (ADS)

Mahović, Nataša Strelec; Horvath, Akos; Csirmaz, Kalman

2007-02-01

Squall lines and supercells cause severe weather and huge damages in the territory of Croatia and Hungary. These long living events can be recognised by radar very well, but the problem of early warning, especially successful numerical forecast of these phenomena, has not yet been solved in this region. Two case studies are presented here in which dynamical modelling approach gives promising results: a squall line preceding a cold front and a single supercell generated because of a prefrontal instability. The numerical simulation is performed using the PSU/NCAR meso-scale model MM5, with horizontal resolution of 3 km. Lateral boundary conditions are taken from the ECMWF model. The moist processes are resolved by Reisner mixed-phase explicit moisture scheme and for the radiation scheme a rapid radiative transfer model is applied. The analysis nudging technique is applied for the first two hours of the model run. The results of the simulation are very promising. The MM5 model reconstructed the appearance of the convective phenomena and showed the development of thunderstorm into the supercell phase. The model results give very detailed insight into wind changes showing the rotation of supercells, clearly distinguish warm core of the cell and give rather good precipitation estimate. The successful simulation of convective phenomena by a high-resolution MM5 model showed that even smaller scale conditions are contained in synoptic scale patterns, represented in this case by the ECMWF model.

Inquiry learning: Students' perception of light wave phenomena in an informal environment

NASA Astrophysics Data System (ADS)

Ford, Ken

This study involved identifying students' perception of light phenomena and determined if they learned the scientific concepts of light that were presented to them by an interactive science exhibit. The participants in this study made scientific inquiry about light by using a powerful white light source, a prism, converging lenses, diverging lenses, concave and convex mirrors in an informal science setting. The sample used in the study consisted of 40 subjects (15 males and 25 females) in a college program at a University located in the Southern region of the United States. The participants were selected using a convenient sampling process from a population enrolled in a pre-calculus class and a physics class. The participants were engaged in pretest on light wave phenomena using the Inquiry Laboratory Light Island exhibit. After the pretest, the participants were engaged in activities, where they reflected white light off the surface of concave and convex mirrors, refracted white light through converging and diverging lens, and passed white light through a prism. They also made observations of the behavior and characteristics of light from the patterns that it created. After three weeks, the participants were given the Inquiry Laboratory Light Island exhibit posttest. The findings of the study indicated that the means yielded a higher average for the participants' posttest scores. The t-Test results were statistically significant, which confirmed that the concepts of light wave phenomena were perceived and learned by the participants. The Inquiry Laboratory survey questions analyzed using the chi-square test suggested that participants were in agreement with the concepts about light. In addition, Cramer's phi and Cramer's V suggested a moderate relationship and association between the genders of the participants on the concepts of light wave phenomena. Furthermore, the interview and observation protocol processes confirmed that students perceived and learned the

X-ray Spectroscopy and Imaging as Multiscale Probes of Intercalation Phenomena in Cathode Materials

NASA Astrophysics Data System (ADS)

Horrocks, Gregory A.; De Jesus, Luis R.; Andrews, Justin L.; Banerjee, Sarbajit

2017-09-01

Intercalation phenomena are at the heart of modern electrochemical energy storage. Nevertheless, as out-of-equilibrium processes involving concomitant mass and charge transport, such phenomena can be difficult to engineer in a predictive manner. The rational design of electrode architectures requires mechanistic understanding of physical phenomena spanning multiple length scales, from atomistic distortions and electron localization at individual transition metal centers to phase inhomogeneities and intercalation gradients in individual particles and concentration variances across ensembles of particles. In this review article, we discuss the importance of the electronic structure in mediating electrochemical storage and mesoscale heterogeneity. In particular, we discuss x-ray spectroscopy and imaging probes of electronic and atomistic structure as well as statistical regression methods that allow for monitoring of the evolution of the electronic structure as a function of intercalation. The layered α-phase of V2O5 is used as a model system to develop fundamental ideas on the origins of mesoscale heterogeneity.

Design, development, and fabrication of a prototype ice pack heat sink subsystem. Flight experiment physical phenomena experiment chest

NASA Technical Reports Server (NTRS)

Roebelen, G. J., Jr.; Dean, W. C., II

1975-01-01

The concept of a flight experiment physical phenomena experiment chest, to be used eventually for investigating and demonstrating ice pack heat sink subsystem physical phenomena during a zero gravity flight experiment, is described.

Experimental Study on Short Circuit Phenomena in Air Switch of Distribution Line due to Sparkover between Different Poles on Which One Surge Arrester of the Three Ones is Omitted

NASA Astrophysics Data System (ADS)

Sato, Tomoyuki; Uemura, Satoshi; Asakawa, Akira; Yokoyama, Shigeru; Honda, Hideki; Horikoshi, Kazuhiro

In this study, we experimentally examined the possibility of the internal short circuit of an air switch due to the sparkover between different poles under the condition that no surge arrester exists in neighboring poles and one of three surge arresters is omitted at the pole with an air switch. Experiments at Shiobara Testing Yard and Akagi Testing Center of CRIEPI clarified the following. Fault current may flow via the grounding point of a pole with an air switch and that of the next pole on a different phase from grounded phase of the pole with an air switch. If the low-voltage wire, overhead ground wire or communication wire forms a short circuit between them, ultimately the air switch may burn out. Moreover Fault current continues even if the length of the short-circuit between different poles is increased. Although the increase of the short-circuit length results in the increase of wire impedance, the amount of increase is still small compared with source impedance.

Indoor air quality in urban nurseries at Porto city: Particulate matter assessment

NASA Astrophysics Data System (ADS)

Branco, P. T. B. S.; Alvim-Ferraz, M. C. M.; Martins, F. G.; Sousa, S. I. V.

2014-02-01

Indoor air quality in nurseries is an interesting case of study mainly due to children's high vulnerability to exposure to air pollution (with special attention to younger ones), and because nursery is the public environment where young children spend most of their time. Particulate matter (PM) constitutes one of the air pollutants with greater interest. In fact, it can cause acute effects on children's health, as well as may contribute to the prevalence of chronic respiratory diseases like asthma. Thus, the main objectives of this study were: i) to evaluate indoor concentrations of particulate matter (PM1, PM2.5, PM10 and PMTotal) on different indoor microenvironments in urban nurseries of Porto city; and ii) to analyse those concentrations according to guidelines and references for indoor air quality and children's health. Indoor PM measurements were performed in several class and lunch rooms in three nurseries on weekdays and weekends. Outdoor PM10 concentrations were also obtained to determine I/O ratios. PM concentrations were often found high in the studied classrooms, especially for the finer fractions, reaching maxima hourly mean concentrations of 145 μg m-3 for PM1 and 158 μg m-3 PM2.5, being often above the limits recommended by WHO, reaching 80% of exceedances for PM2.5, which is concerning in terms of exposure effects on children's health. Mean I/O ratios were always above 1 and most times above 2 showing that indoor sources (re-suspension phenomena due to children's activities, cleaning and cooking) were clearly the main contributors to indoor PM concentrations when compared with the outdoor influence. Though, poor ventilation to outdoors in classrooms affected indoor air quality by increasing the PM accumulation. So, enhancing air renovation rate and performing cleaning activities after the occupancy period could be good practices to reduce PM indoor air concentrations in nurseries and, consequently, to improve children's health and welfare.

Flow phenomena on plates and airfoils of short span

NASA Technical Reports Server (NTRS)

Winter, H

1936-01-01

Investigations on the flow phenomena at plates and cambered models were carried out with the aid of force measurements, some pressure distribution measurements, and photographic observation. The experimental methods are described and the results given. Section III of this work gives a comprehensive account of the results and enables us to see how nearly the lift line and lift surface theories agree with the experimental results.

Optical Phenomena Observed upon Some Launches of Russian Rockets

NASA Astrophysics Data System (ADS)

Kozlov, S. I.; Nilolaishvili, S. Sh.; Platov, Yu. V.

2018-01-01

In this paper, unusual optical phenomena observed in our country and abroad upon launches of Russian rockets are discussed and interpreted: they are regarded as the aftereffects of sunlight scattering by gas-dust clouds created by rocket fuel combustion products in different modes of engine operation. The results of instrumental observations of the clouds can be used to study physical processes in the upper atmosphere.

The role of spinning electrons in paramagnetic phenomena

NASA Technical Reports Server (NTRS)

Bose, D. M.

1986-01-01

An attempt is made to explain paramagnetic phenomena without assuming the orientation of a molecule or ion in a magnetic field. Only the spin angular momentum is assumed to be responsible. A derivative of the Gurie-Langevin law and the magnetic moments of ions are given as a function of the number of electrons in an inner, incomplete shell. An explanation of Gerlach's experiments with iron and nickel vapors is attempted. An explanation of magnetomechanical experiments with ferromagne elements is given.

Structure for identifying, locating and quantifying physical phenomena

DOEpatents

Richardson, John G.

2006-10-24

A method and system for detecting, locating and quantifying a physical phenomena such as strain or a deformation in a structure. A minimum resolvable distance along the structure is selected and a quantity of laterally adjacent conductors is determined. Each conductor includes a plurality of segments coupled in series which define the minimum resolvable distance along the structure. When a deformation occurs, changes in the defined energy transmission characteristics along each conductor are compared to determine which segment contains the deformation.

Review of Air Vitiation Effects on Scramjet Ignition and Flameholding Combustion Processes

NASA Technical Reports Server (NTRS)

Pellett, G. L.; Bruno, Claudio; Chinitz, W.

2002-01-01

This paper offers a detailed review and analysis of more than 100 papers on the physics and chemistry of scramjet ignition and flameholding combustion processes, and the known effects of air vitiation on these processes. The paper attempts to explain vitiation effects in terms of known chemical kinetics and flame propagation phenomena. Scaling methodology is also examined, and a highly simplified Damkoehler scaling technique based on OH radical production/destruction is developed to extrapolate ground test results, affected by vitiation, to flight testing conditions. The long term goal of this effort is to help provide effective means for extrapolating ground test data to flight, and thus to reduce the time and expense of both ground and flight testing.

Numerical study of turbulence-influence mechanism on arc characteristics in an air direct current circuit breaker

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

Wu, Mingliang; Yang, Fei, E-mail: yfei2007@mail.xjtu.edu.cn; Rong, Mingzhe

This paper focuses on the numerical investigation of arc characteristics in an air direct current circuit breaker (air DCCB). Using magneto-hydrodynamics (MHD) theory, 3D laminar model and turbulence model are constructed and calculated. The standard k-epsilon model is utilized to consider the turbulence effect in the arc chamber of the DCCB. Several important phenomena are found: the arc column in the turbulence-model case is more extensive, moves much more slowly than the counterpart in the laminar-model case, and shows stagnation at the entrance of the chamber, unlike in the laminar-model case. Moreover, the arc voltage in the turbulence-model case ismore » much lower than in the laminar-model case. However, the results in the turbulence-model case show a much better agreement with the results of the breaking experiments under DC condition than in the laminar-model case, which is contradictory to the previous conclusions from the arc researches of both the low-voltage circuit breaker and the sulfur hexafluoride (SF6) nozzle. First, in the previous air-arc research of the low-voltage circuit breaker, it is assumed that the air plasma inside the chamber is in the state of laminar, and the laminar-model application gives quite satisfactory results compared with the experiments, while in this paper, the laminar-model application works badly. Second, the turbulence-model application in the arc research of the SF6-nozzle performs much better and gives higher arc voltage than the laminar-model application does, whereas in this paper, the turbulence-model application predicts lower arc voltage than the laminar-model application does. Based on the analysis of simulation results in detail, the mechanism of the above phenomena is revealed. The transport coefficients are strongly changed by turbulence, which will enhance the arc diffusion and make the arc volume much larger. Consequently, the arc appearance and the distribution of Lorentz force in the turbulence

Flow-field differences and electromagnetic-field properties of air and N2 inductively coupled plasmas

NASA Astrophysics Data System (ADS)

Yu, Minghao; Yamada, Kazuhiko; Takahashi, Yusuke; Liu, Kai; Zhao, Tong

2016-12-01

A numerical model for simulating air and nitrogen inductively coupled plasmas (ICPs) was developed considering thermochemical nonequilibrium and the third-order electron transport properties. A modified far-field electromagnetic model was introduced and tightly coupled with the flow field equations to describe the Joule heating and inductive discharge phenomena. In total, 11 species and 49 chemical reactions of air, which include 5 species and 8 chemical reactions of nitrogen, were employed to model the chemical reaction process. The internal energy transfers among translational, vibrational, rotational, and electronic energy modes of chemical species were taken into account to study thermal nonequilibrium effects. The low-Reynolds number Abe-Kondoh-Nagano k-ɛ turbulence model was employed to consider the turbulent heat transfer. In this study, the fundamental characteristics of an ICP flow, such as the weak ionization, high temperature but low velocity in the torch, and wide area of the plasma plume, were reproduced by the developed numerical model. The flow field differences between the air and nitrogen ICP flows inside the 10-kW ICP wind tunnel were made clear. The interactions between the electromagnetic and flow fields were also revealed for an inductive discharge.