Sample records for capillary fringe

  1. Natural Attenuation of Nonvolatile Contaminants in the Capillary Fringe.

    PubMed

    Kurt, Zohre; Mack, E Erin; Spain, Jim C

    2016-09-20

    When anoxic polluted groundwater encounters the overlying vadose zone an oxic/anoxic interface is created, often near the capillary fringe. Biodegradation of volatile contaminants in the capillary fringe can prevent vapor migration. In contrast, the biodegradation of nonvolatile contaminants in the vadose zone has received comparatively little attention. Nonvolatile compounds do not cause vapor intrusion, but they still move with the groundwater and are major contaminants. Aniline (AN) and diphenylamine (DPA) are examples of toxic nonvolatile contaminants found often at dye and munitions manufacturing sites. In this study, we tested the hypothesis that bacteria can aerobically biodegrade AN and DPA in the capillary fringe and decrease the contaminant concentrations in the anoxic plume beneath the vadose zone. Laboratory multiport columns that represented the unsaturated zone were used to evaluate degradation of AN or DPA in contaminated water. The biodegradation fluxes of the contaminants were estimated to be 113 ± 26 mg AN·m(-2)·h(-1) and 76 ± 18 mg DPA·m(-2)·h(-1) in the presence of bacteria known to degrade AN and DPA. Oxygen and contaminant profiles along with enumeration of bacterial populations indicated that most of the biodegradation took place within the lower part of the capillary fringe. The results indicate that bacteria capable of contaminant biodegradation in the capillary fringe can create a sink for nonvolatile contaminants.

  2. IN SITU ABIOTIC DETOXIFICATION AND IMMOBILIZATION OF HEXAVALENT CHROMIUM IN THE CAPILLARY FRINGE ZONE

    EPA Science Inventory

    Detailed site characterization data from the former electroplating shop at the U.S. Coast Guard Air Support Center, Elizabeth City, North Carolina suggested that the elevated Cr(VI) in the capillary fringe area had contaminated the ground water at the site. Most of the mobile Cr(...

  3. Unsaturated flow characterization utilizing water content data collected within the capillary fringe

    USGS Publications Warehouse

    Baehr, Arthur; Reilly, Timothy J.

    2014-01-01

    An analysis is presented to determine unsaturated zone hydraulic parameters based on detailed water content profiles, which can be readily acquired during hydrological investigations. Core samples taken through the unsaturated zone allow for the acquisition of gravimetrically determined water content data as a function of elevation at 3 inch intervals. This dense spacing of data provides several measurements of the water content within the capillary fringe, which are utilized to determine capillary pressure function parameters via least-squares calibration. The water content data collected above the capillary fringe are used to calculate dimensionless flow as a function of elevation providing a snapshot characterization of flow through the unsaturated zone. The water content at a flow stagnation point provides an in situ estimate of specific yield. In situ determinations of capillary pressure function parameters utilizing this method, together with particle-size distributions, can provide a valuable supplement to data libraries of unsaturated zone hydraulic parameters. The method is illustrated using data collected from plots within an agricultural research facility in Wisconsin.

  4. Biodegradation of phenol, salicylic acid, benzenesulfonic acid, and iomeprol by Pseudomonas fluorescens in the capillary fringe

    NASA Astrophysics Data System (ADS)

    Hack, Norman; Reinwand, Christian; Abbt-Braun, Gudrun; Horn, Harald; Frimmel, Fritz H.

    2015-12-01

    Mass transfer and biological transformation phenomena in the capillary fringe were studied using phenol, salicylic acid, benzenesulfonic acid, and the iodinated X-ray contrast agent iomeprol as model organic compounds and the microorganism strain Pseudomonas fluorescens. Three experimental approaches were used: Batch experiments (uniform water saturation and transport by diffusion), in static columns (with a gradient of water saturation and advective transport in the capillaries) and in a flow-through cell (with a gradient of water saturation and transport by horizontal and vertical flow: 2-dimension flow-through microcosm). The reactors employed for the experiments were filled with quartz sand of defined particle size distribution (dp = 200…600 μm, porosity ε = 0.42). Batch experiments showed that phenol and salicylic acid have a high, whereas benzenesulfonic acid and iomeprol have a quite low potential for biodegradation under aerobic conditions and in a matrix nearly close to water saturation. Batch experiments under anoxic conditions with nitrate as electron acceptor revealed that the biodegradation of the model compounds was lower than under aerobic conditions. Nevertheless, the experiments showed that the moisture content was also responsible for an optimized transport in the liquid phase of a porous medium. Biodegradation in the capillary fringe was found to be influenced by both the moisture content and availability of the dissolved substrate, as seen in static column experiments. The gas-liquid mass transfer of oxygen also played an important role for the biological activity. In static column experiments under aerobic conditions, the highest biodegradation was found in the capillary fringe (e.g. βt/β0 (phenol) = 0 after t = 6 d) relative to the zone below the water table and unsaturated zone. The highest biodegradation occurred in the flow-through cell experiment where the height of the capillary fringe was largest.

  5. Biodegradation of phenol, salicylic acid, benzenesulfonic acid, and iomeprol by Pseudomonas fluorescens in the capillary fringe.

    PubMed

    Hack, Norman; Reinwand, Christian; Abbt-Braun, Gudrun; Horn, Harald; Frimmel, Fritz H

    2015-12-01

    Mass transfer and biological transformation phenomena in the capillary fringe were studied using phenol, salicylic acid, benzenesulfonic acid, and the iodinated X-ray contrast agent iomeprol as model organic compounds and the microorganism strain Pseudomonas fluorescens. Three experimental approaches were used: Batch experiments (uniform water saturation and transport by diffusion), in static columns (with a gradient of water saturation and advective transport in the capillaries) and in a flow-through cell (with a gradient of water saturation and transport by horizontal and vertical flow: 2-dimension flow-through microcosm). The reactors employed for the experiments were filled with quartz sand of defined particle size distribution (dp=200...600 μm, porosity ε=0.42). Batch experiments showed that phenol and salicylic acid have a high, whereas benzenesulfonic acid and iomeprol have a quite low potential for biodegradation under aerobic conditions and in a matrix nearly close to water saturation. Batch experiments under anoxic conditions with nitrate as electron acceptor revealed that the biodegradation of the model compounds was lower than under aerobic conditions. Nevertheless, the experiments showed that the moisture content was also responsible for an optimized transport in the liquid phase of a porous medium. Biodegradation in the capillary fringe was found to be influenced by both the moisture content and availability of the dissolved substrate, as seen in static column experiments. The gas-liquid mass transfer of oxygen also played an important role for the biological activity. In static column experiments under aerobic conditions, the highest biodegradation was found in the capillary fringe (e.g. βt/β0 (phenol)=0 after t=6 d) relative to the zone below the water table and unsaturated zone. The highest biodegradation occurred in the flow-through cell experiment where the height of the capillary fringe was largest. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Subsurface Flow and Moisture Dynamics in Response to Swash Motions: Effects of Beach Hydraulic Conductivity and Capillarity

    NASA Astrophysics Data System (ADS)

    Geng, Xiaolong; Heiss, James W.; Michael, Holly A.; Boufadel, Michel C.

    2017-12-01

    A combined field and numerical study was conducted to investigate dynamics of subsurface flow and moisture response to waves in the swash zone of a sandy beach located on Cape Henlopen, DE. A density-dependent variably saturated flow model MARUN was used to simulate subsurface flow beneath the swash zone. Values of hydraulic conductivity (K) and characteristic pore size (α, a capillary fringe property) were varied to evaluate their effects on subsurface flow and moisture dynamics in response to swash motions in beach aquifers. The site-specific modeling results were validated against spatiotemporal measurements of moisture and pore pressure in the beach. Sensitivity analyses indicated that the hydraulic conductivity and capillary fringe thickness of the beach greatly influenced groundwater flow pathways and associated transit times in the swash zone. A higher value of K enhanced swash-induced seawater infiltration into the beach, thereby resulting in a faster expansion of a wedge of high moisture content induced by swash cycles, and a flatter water table mound beneath the swash zone. In contrast, a thicker capillary fringe retained higher moisture content near the beach surface, and thus, significantly reduced the available pore space for infiltration of seawater. This attenuated wave effects on pore water flow in the unsaturated zone of the beach. Also, a thicker capillary fringe enhanced horizontal flow driven by the larger-scale hydraulic gradient caused by tides.

  7. Transport of volatile organic compounds across the capillary fringe

    USGS Publications Warehouse

    McCarthy, Kathleen A.; Johnson, Richard L.

    1993-01-01

    Physical experiments were conducted to investigate the transport of a dissolved volatile organic compound (trichloroethylene, TCE) from shallow groundwater to the unsaturated zone under a variety of conditions including changes in the soil moisture profile and water table position. Experimental data indicated that at moderate groundwater velocities (0.1 m/d), vertical mechanical dispersion was negligible and molecular diffusion was the dominant vertical transport mechanism. Under these conditions, TCE concentrations decreased nearly 3 orders of magnitude across the capillary fringe and soil gas concentrations remained low relative to those of underlying groundwater. Data collected during a water table drop showed a short-term increase in concentrations throughout most of the unsaturated zone, but these concentrations quickly declined and approached initial values after the water table was returned to its original level. In the deep part of the unsaturated zone, the water table drop resulted in a long-term decrease in concentrations, illustrating the effects of hysteresis in the soil moisture profile. A two-dimensional random walk advection-diffusion model was developed to simulate the experimental conditions, and numerical simulations agreed well with experimental data. A simpler, one-dimensional finite-difference diffusion-dispersion model was also developed. One-dimensional simulations based on molecular diffusion also agreed well with experimental data. Simulations which incorporated mechanical dispersion tended to overestimate flux across the capillary fringe. Good agreement between the one- and two-dimensional models suggested that a simple, one-dimensional approximation of vertical transport across the capillary fringe can be useful when conditions are appropriate.

  8. FIELD EVALUATION OF IN-SITU REDOX MANIPULATION FOR REMEDIATING CHROMIUM CONTAMINATED GROUND WATER AND SEDIMENT

    EPA Science Inventory

    Historical data from the electroplating shop at the U.S Coast Guard Air Support Center site, Elizabeth City, North Carolina, suggested that the elevated Cr(VI) in the capillary fringe area had contaminated the ground water. Most of the mobile Cr(VI) is present in the capillary z...

  9. Modeling Subsurface Hydrology in Floodplains

    NASA Astrophysics Data System (ADS)

    Evans, Cristina M.; Dritschel, David G.; Singer, Michael B.

    2018-03-01

    Soil-moisture patterns in floodplains are highly dynamic, owing to the complex relationships between soil properties, climatic conditions at the surface, and the position of the water table. Given this complexity, along with climate change scenarios in many regions, there is a need for a model to investigate the implications of different conditions on water availability to riparian vegetation. We present a model, HaughFlow, which is able to predict coupled water movement in the vadose and phreatic zones of hydraulically connected floodplains. Model output was calibrated and evaluated at six sites in Australia to identify key patterns in subsurface hydrology. This study identifies the importance of the capillary fringe in vadose zone hydrology due to its water storage capacity and creation of conductive pathways. Following peaks in water table elevation, water can be stored in the capillary fringe for up to months (depending on the soil properties). This water can provide a critical resource for vegetation that is unable to access the water table. When water table peaks coincide with heavy rainfall events, the capillary fringe can support saturation of the entire soil profile. HaughFlow is used to investigate the water availability to riparian vegetation, producing daily output of water content in the soil over decadal time periods within different depth ranges. These outputs can be summarized to support scientific investigations of plant-water relations, as well as in management applications.

  10. Impact of Heterogeneity on Vadose Zone Drainage During Pumping: Numerical Simulations of the Borden Aquifer

    NASA Astrophysics Data System (ADS)

    Bunn, M. I.; Jones, J.; Endres, A. L.

    2009-05-01

    Unconfined aquifers are in direct contact with the earth's surface; hence, they are an important focus in groundwater recharge and contaminant transport studies. While pumping tests have long been used to quantify aquifer properties, the contribution of drainage from the vadose zone during pumping has been the subject of debate for decades. In 2001, a highly detailed data set was collected during a seven-day pumping test in the unconfined aquifer at CFB Borden, Ontario (Bevan et al., 2005). The frequent observation of moisture content profiles during the test has initiated a closer examination of the vadose zone response to pumping. The moisture profiles collected during the test were obtained using a neutron probe. The neutron data depicts a capillary fringe thickness that increases with both proximity to the pumping well and duration of pumping. This capillary fringe extension results in delayed drainage that persists to the end of the seven-day test with the shape of the transition zone remaining constant (Bevan et al., 2005). Simulations of the pumping test were conducted using Hydrogeosphere (Therrien et al., 2006). Initial simulations were completed based on the conceptual model of a homogeneous and slightly anisotropic aquifer. The simulation results replicated the observed piezometric response, but were unable to produce any change in the thickness of the capillary fringe. It was hypothesized that the discrepancy between observations and simulation results may be the result of assumptions such as the homogeneity of the hydraulic conductivity field. In an effort to replicate this potential mechanism for the observed extension, the conceptual model was updated to better reflect the mildly heterogeneous hydraulic conductivity field of the Borden aquifer. Conductivity fields were generated using the statistical description of the Borden aquifer given by Sudicky (1986) with an adjusted mean log conductivity to better approximate the observed piezometric response. The inclusion of heterogeneity appears to have little effect on the hydraulic head drawdown, or the thickness of the capillary fringe. Heterogeneity does lead to delayed drainage in the drier portion of the vadose zone, where volumetric water content is less than 0.13 m3/m3. This effect is more pronounced with proximity to the pumping well, and is negligible at 15 m from the well. The amount of excess moisture in the vadose zone does not appear to be a function of pumping duration.

  11. BIODEGRADATION OF HYDROCARBON VAPORS IN THE UNSATURATED ZONE

    EPA Science Inventory

    The time-averaged concentration of hydrocarbon and oxygen vapors were measured in the unsaturated zone above the residually contaminated capillary fringe at the U.S. Coast Guard Air Station in Traverse City, Michigan. Total hydrocarbon and oxygen vapor concentrations were observe...

  12. FIELD SAMPLING OF RESIDUAL AVIATION GASOLINE IN SANDY SOIL

    EPA Science Inventory

    Two complimentary field sampling methods for the determination of residual aviation gasoline content in the contaminated capillary fringe of a fine, uniform, sandy soil were investigated. The first method featured filed extrusion of core barrels into pint size Mason jars, while ...

  13. MOLECULAR CHARACTERIZATION OF MICROBIAL COMMUNITIES IN A JP-4 FUEL CONTAMINATED SOIL

    EPA Science Inventory

    In this study, lipid biomarker characterization of the bacterial and eukaryotic communities was combined with PCR-DGGE analysis of the eubacterial community to evaluate correlation between JP-4 fuel concentration and community structure shifts. Vadose, capillary fringe and satur...

  14. LNAPL DISTRIBUTION AND HYDROCARBON VAPOR TRANSPORT IN THE CAPILLARY FRINGE

    EPA Science Inventory

    Vertical distributions of water and light nonaqueous phase liquid (LNAPL) from a well document aviation gasoline spill at the US Coast Guard Air Station in Traverse City, Michigan were measured. Two field sampling methods for the determination of LNAPL content were presented. E...

  15. GROUND WATER SAMPLING OF VOCS IN THE WATER/CAPILLARY FRINGE AREA FOR VAPOR INTRUSION ASSESSMENT

    EPA Science Inventory

    Vapor intrusion has recently been considered a major pathway for increased indoor air contamination from certain volatile organic contaminants (VOCs). The recent Draft EPA Subsurface Vapor Intrusion Guidance Document states that ground water samples should be obtained from the u...

  16. Quasi 3D modeling of water flow in vadose zone and groundwater

    USDA-ARS?s Scientific Manuscript database

    The complexity of subsurface flow systems calls for a variety of concepts leading to the multiplicity of simplified flow models. One habitual simplification is based on the assumption that lateral flow and transport in unsaturated zone are not significant unless the capillary fringe is involved. In ...

  17. THE HYDROCARBON SPILL SCREENING MODEL (HSSM), VOLUME 2: THEORETICAL BACKGROUND AND SOURCE CODES

    EPA Science Inventory

    A screening model for subsurface release of a nonaqueous phase liquid which is less dense than water (LNAPL) is presented. The model conceptualizes the release as consisting of 1) vertical transport from near the surface to the capillary fringe, 2) radial spreading of an LNAPL l...

  18. VOC SAMPLING IN THE WATER TABLE/CAPILLARY FRINGE AREA FOR ASSESSING IMPACT ON VAPOR INTRUSION AND INDOOR AIR QUALITY

    EPA Science Inventory

    Vapor intrusion has been determined to be a major pathway for increased indoor air contamination from volatile organic contaminants (VOCs) at certain contaminated sites. In order to properly assess vapor intrusion, it is important to adequately evaluate VOC concentrations in the...

  19. Numerical Analysis of Infiltration Into a Sand Profile Bounded by a Capillary Fringe

    NASA Astrophysics Data System (ADS)

    Curtis, Alan A.; Watson, Keith K.

    1980-04-01

    The rapid response sometimes observed in a tile drain system following surface ponding of water is discussed in terms of the air compressibility effect. An earlier numerical study describing water movement into a bounded profile with a lower boundary impermeable to the passage of both air and water is reviewed with particular reference to the validity of the time-dependent boundary condition transformation used in simulating the inhibiting effects of the air pressure increase on infiltration. The extension of the transformation approach to a profile bounded by a capillary fringe is then considered in detail, and the results of numerical analyses are presented for infiltration into two columns of a fine sand initially in hydraulic equilibrium from a prior gravity drainage regime. The shorter column develops a steady state flow condition at short times which is consistent with earlier experimental findings. In contrast, the pressure of the entrapped air in the longer column gradually increases as infiltration proceeds until the analysis is terminated when air escape through the lower boundary is imminent.

  20. Liquid crystal-based biosensor with backscattering interferometry: A quantitative approach.

    PubMed

    Khan, Mashooq; Park, Soo-Young

    2017-01-15

    We developed a new technology that uses backscattering interferometry (BSI) to quantitatively measure nematic liquid crystal (NLC)-based biosensors, those usually relied on texture reading for on/off signals. The LC-based BSI comprised an octadecyltrichlorosilane (OTS)-coated square capillary filled with 4-cyano-4'-pentylbiphenyl (5CB, a nematic LC at room temperature). The LC/water interface in the capillary was functionalized by a coating of poly(acrylicacid-b-4-cyanobiphenyl-4'-oxyundecylacrylate) (PAA-b-LCP) and immobilized with the enzymes glucose oxidase (GOx) and horseradish peroxidase (HRP) through covalent linkage to the PAA chains (5CB PAA-GOx:HRP ) for glucose detection. Laser irradiation of the LC near the LC/water interface resulted in backscattered fringes with high contrast. The change in the spatial position of the fringes (because of the change in the orientation of the LC caused by the GOx:HRP enzymatic reaction of glucose) altered the output voltage of the photodetector when its active area was aligned with the edge of one of the fringes. The change in the intensity at the photodetector allowed the detection limit of the instrument to be as low as 0.008mM with a linear range of 0.02-9mM in a short response time (~60s). This LC-based BSI technique allows for quantitative, sensitive, selective, reproducible, easily obtainable, and interference-free detection in a large linear dynamic range and for practical applications with human serum. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Microbial growth and transport in saturated and unsaturated porous media

    NASA Astrophysics Data System (ADS)

    Hron, Pavel; Jost, Daniel; Bastian, Peter; Ippisch, Olaf

    2014-05-01

    There is a considerable ongoing effort aimed at understanding the behavior of microorganisms in porous media. Microbial activity is of significant interest in various environmental applications such as in situ bioremediation, protection of drinking water supplies and for subsurface geochemistry in general. The main limiting factors for bacterial growth are the availability of electron acceptors, nutrients and bio-available water. The capillary fringe, defined - in a wider sense than usual - as the region of the subsurface above the groundwater table, but still dominated by capillary rise, is a region where all these factors are abundantly available. It is thus a region where high microbial activity is to be expected. In a research unit 'Dynamic Capillary Fringes - A Multidisciplinary Approach (DyCap)' founded by the German Research Foundation (DFG), the growth of microorganisms in the capillary fringe was studied experimentally and with numerical simulations. Processes like component transport and diffusion, exchange between the liquid phase and the gas phase, microbial growth and cell attachment and detachment were incorporated into a numerical simulator. The growth of the facultative anaerobic Escherichia coli as a function of nutrient availability and oxygen concentration in the liquid phase is modeled with modified Monod-type models and modifications for the switch between aerobic and anaerobic growth. Laboratory batch experiments with aqueous solutions of bacteria have been carried out under various combinations of oxygen concentrations in the gas phase and added amounts of dissolved organic carbon to determine the growth model parameters by solution of a parameter estimation problem. For the transport of bacteria the adhesion to phase boundaries is also very important. As microorganisms are transported through porous media, they are removed from the pore fluid by physicochemical filtration (attachment to sediment grain surfaces) or are adhering to gas-water interface. The cell attachment and detachment model was based on flow-through experiments and the parameters were obtained by fitting the model to measured bacteria breakthrough curves. Experiments on bacterial growth in porous media with and without groundwater flow were performed in Hele-Shaw cells filled with quartz sands. The cell density was determined by the fluorescence of a special protein produced by the genetically modified strain of E. coli. The simulation results are compared to experimental data and different modeling approaches are discussed.

  2. Measurements and modelling of beach groundwater flow in the swash-zone: a review

    NASA Astrophysics Data System (ADS)

    Horn, Diane P.

    2006-04-01

    This paper reviews research on beach groundwater dynamics and identifies research questions which will need to be answered before swash zone sediment transport and beach profile evolution can be successfully modelled. Beach groundwater hydrodynamics are a result of combined forcing from the tide and waves at a range of frequencies, and a large number of observations exist which describe the shape and elevation of the beach watertable in response to tidal forcing at diurnal, semi-diurnal and spring-neap tidal frequencies. Models of beach watertable response to tidal forcing have been successfully validated; however, models of watertable response to wave forcing are less well developed and require verification. Improved predictions of swash zone sediment transport and beach profile evolution cannot be achieved unless the complex fluid and sediment interactions between the surface flow and the beach groundwater are better understood, particularly the sensitivity of sediment transport processes to flow perpendicular to the permeable bed. The presence of a capillary fringe, particularly when it lies just below the sand surface, has influences on beach groundwater dynamics. The presence of a capillary fringe can have a significant effect on the exchange of water between the ocean and the coastal aquifer, particularly in terms of the storage capacity of the aquifer. Field and laboratory observations have also shown that natural groundwater waves usually propagate faster and decay more slowly in aquifers with a capillary fringe, and observations which suggest that horizontal flows may also occur in the capillary zone have been reported. The effects of infiltration and exfiltration are generally invoked to explain why beaches with a low watertable tend to accrete and beaches with a high watertable tend to erode. However, the relative importance of processes such as infiltration losses in the swash, changes in the effective weight of the sediment, and modified shear stress due to boundary layer thinning, are not yet clear. Experimental work on the influence of seepage flows within sediment beds provides conflicting results concerning the effect on bed stability. Both modelling and experimental work indicates that the hydraulic conductivity of the beach is a critical parameter. However, hydraulic conductivity varies both spatially and temporally on beaches, particularly on gravel and mixed sand and gravel beaches. Another important, but poorly understood, consideration in beach groundwater studies is the role of air encapsulation during the wetting of beach sand.

  3. Results and Lessons Learned Interim Report: Altus AFB Site

    DTIC Science & Technology

    2005-07-07

    from the Altus AFB RFI Report Attachment B: Geologic Logs and Static Water Levels Attachment C: Results of Groundwater Analyses Attachment D: Results...including: soil lithology, depth to groundwater , height of capillary fringe, soil hydraulic conductivity and air permeability, soil water retention...were gauged to determine whether groundwater had infiltrated the well and to measure the static water level. Monitoring wells installed for the

  4. Vadose zone microbiology

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

    Kieft, Thomas L.; Brockman, Fred J.

    2001-01-17

    The vadose zone is defined as the portion of the terrestrial subsurface that extends from the land surface downward to the water table. As such, it comprises the surface soil (the rooting zone), the underlying subsoil, and the capillary fringe that directly overlies the water table. The unsaturated zone between the rooting zone and the capillary fringe is termed the "intermediate zone" (Chapelle, 1993). The vadose zone has also been defined as the unsaturated zone, since the sediment pores and/or rock fractures are generally not completely water filled, but instead contain both water and air. The latter characteristic results inmore » the term "zone of aeration" to describe the vadose zone. The terms "vadose zone," "unsaturated zone", and "zone of aeration" are nearly synonymous, except that the vadose zone may contain regions of perched water that are actually saturated. The term "subsoil" has also been used for studies of shallow areas of the subsurface immediately below the rooting zone. This review focuses almost exclusively on the unsaturated region beneath the soil layer since there is already an extensive body of literature on surface soil microbial communities and process, e.g., Paul and Clark (1989), Metting (1993), Richter and Markowitz, (1995), and Sylvia et al. (1998); whereas the deeper strata of the unsaturated zone have only recently come under scrutiny for their microbiological properties.« less

  5. United States Air Force Environmental Restoration Program. Guidance on Soil Vapor Extraction Optimization

    DTIC Science & Technology

    2001-06-01

    Pump Exposed Capillary Fringe SVE System Pneumatic/ Hydraulic Fracturing Points Increased Advective Flow draw\\svehandbk1.cdr aee p1 4/5/01 022/736300...propagate further from the extraction well, increasing the advective flow zone round the well. Pneumatic and hydraulic fracturing are the primary methods...enhancing existing fractures and increasing the secondary fracture network. Hydraulic fracturing involves the injection of water or slurry into the

  6. Phreatophytes under stress: transpiration and stomatal conductance of saltcedar (Tamarix spp.) in a high-salinity environment

    USGS Publications Warehouse

    Glenn, Edward P.; Nagler, Pamela L.; Morino, Kiyomi; Hultine, Kevin

    2013-01-01

    Conclusions: Salts accumulated in the vadose zone at both sites so usable water was confined to the saturated capillary fringe above the aquifer. Existence of a saline aquifer imposes several types of constraints on phreatophyte EG, which need to be considered in models of plant water uptake. The heterogeneous nature of saltcedar EG over river terraces introduces potential errors into estimates of ET by wide-area methods.

  7. Nitrogen fluxes through unsaturated zones in five agricultural settings across the USA

    NASA Astrophysics Data System (ADS)

    Green, C. T.; Fisher, L. H.; Bekins, B. A.

    2006-12-01

    The main controls on nitrogen (N) fluxes between the root zone and the water table were determined for agricultural sites in California, Washington, Nebraska, Indiana, and Maryland in 2004 and 2005. Sites included irrigated and non-irrigated fields; soil textures ranging from clay to sand; crops including corn, soybeans, almonds, and pasture; and unsaturated zone thicknesses ranging from 0.5 to 20 m. Chemical analyses of water from lysimeters, shallow wells, and sediment cores indicate that advective transport of nitrate is the dominant process affecting the rate of N transport below the root zone. Vertical profiles of (1) N species, (2) stable N and O isotopes, and (3) oxygen gas in unsaturated zone air and shallow ground water, and correlations between N and other agricultural chemicals indicate that reactions do not greatly affect N concentrations between the root zone and the capillary fringe. Relatively stable concentrations at depths greater than a few meters allow calculation of nitrogen fluxes to the saturated zone. These fluxes are equivalent to 14 - 64% of the N application rates. At the same locations, median vertical fluxes of N in ground water are generally lower, ranging from 4 - 37% of N application rates. The lower nitrate fluxes in ground water reflect processes including lateral flow to tile drains and denitrification in the capillary fringe, as well as historical changes in N inputs.

  8. 3D mouse shape reconstruction based on phase-shifting algorithm for fluorescence molecular tomography imaging system.

    PubMed

    Zhao, Yue; Zhu, Dianwen; Baikejiang, Reheman; Li, Changqing

    2015-11-10

    This work introduces a fast, low-cost, robust method based on fringe pattern and phase shifting to obtain three-dimensional (3D) mouse surface geometry for fluorescence molecular tomography (FMT) imaging. We used two pico projector/webcam pairs to project and capture fringe patterns from different views. We first calibrated the pico projectors and the webcams to obtain their system parameters. Each pico projector/webcam pair had its own coordinate system. We used a cylindrical calibration bar to calculate the transformation matrix between these two coordinate systems. After that, the pico projectors projected nine fringe patterns with a phase-shifting step of 2π/9 onto the surface of a mouse-shaped phantom. The deformed fringe patterns were captured by the corresponding webcam respectively, and then were used to construct two phase maps, which were further converted to two 3D surfaces composed of scattered points. The two 3D point clouds were further merged into one with the transformation matrix. The surface extraction process took less than 30 seconds. Finally, we applied the Digiwarp method to warp a standard Digimouse into the measured surface. The proposed method can reconstruct the surface of a mouse-sized object with an accuracy of 0.5 mm, which we believe is sufficient to obtain a finite element mesh for FMT imaging. We performed an FMT experiment using a mouse-shaped phantom with one embedded fluorescence capillary target. With the warped finite element mesh, we successfully reconstructed the target, which validated our surface extraction approach.

  9. An Examination of Potential Causes of the Persistent Capillary Fringe Extension Observed During a Pumping Test in an Unconfined Aquifer

    NASA Astrophysics Data System (ADS)

    Bunn, M. I.; Jones, J.; Endres, A. L.

    2008-12-01

    Hydrogeologists quantify the properties of unconfined aquifers by analyzing the data from pumping tests. The most appropriate method of incorporating flow contributions from the vadose zone into these analyses has been the subject of debate for decades. Recently, a highly detailed data set was collected during a seven- day pumping test at CFB Borden, Ontario (Bevan et al., 2005) which has allowed a close examination of the vadose zone response to pumping. Water table drawdown was monitored using pressure transducers in 11 monitoring wells, while moisture profiles were collected 19 times during the 7-day test using neutron logging. The Borden aquifer system is quite homogeneous, and numerical simulations using the variably saturated model InHM resulted in excellent reproduction of the observed hydraulic head drawdowns. Conversely, the simulated moisture profiles correlated poorly with neutron-logging-derived observed profiles. Specifically, the field results show delayed drawdown in the vadose zone, resulting in a persistent and significant extension of the capillary fringe, with the shape of the moisture profile remaining constant through the transition zone. Numerical simulations using various forms of the capillary pressure-saturation relationship with reasonable parameter sets were unable produce the extension. Neutron moisture profiles were selected from three locations (3, 5, and 15 m radial distance from the pumping well) at which an adjacent shallow deep piezometer pair could be used to accurately estimate water table location. Using this data in conjunction with the inverse modeling tool PEST, a set of van Genuchten capillary pressure-saturation parameters was generated to match each observed moisture profile. Horizontal and vertical hydraulic gradients and flow rates at the water table were generated using model output and compared to the fitted parameters. The van Genuchten parameter n was found to have significant scatter in both profile location and observation time when compared to any of the modeled results. The van Genuchten parameter alpha was found to vary linearly as a function of horizontal hydraulic gradient; further the results from all observation locations and times were found to follow the same linear relationship. The likely effects of consolidation, entrapped air, heterogeneity, and hydraulic gradients on the observed moisture profile were also evaluated. Results indicate a need for further investigation into the applicability of laboratory derived steady-state water retention curves for field scale simulations.

  10. Delivery and Establishing Slow Release Carbon Source to the Hanford Vadose Zone Using Colloidal Silica Suspension Injection and Subsequent Gelation - Laboratory Study

    NASA Astrophysics Data System (ADS)

    Zhong, L.; Lee, M. H.; Lee, B.; Yang, S.

    2016-12-01

    Delivery of nutrient to and establish a slow release carbon source in the vadose zone and capillary fringe zone is essential for setting up of a long-lasting bioremediation of contaminations in those zones. Conventional solution-based injection and infiltration approaches are facing challenges to achieve the delivery and remedial goals. Aqueous silica suspensions undergo a delayed gelation process under favorite geochemical conditions. The delay in gelation provides a time window for the injection of the suspension into the subsurface; and the gelation of the amendment-silica suspension enables the amendment-laden gel to stay in the target zone and slowly release the constituents for contaminant remediation. This approach can potentially be applied to deliver bio-nutrients to the vadose zone and capillary fringe zone for enhanced bioremediation and achieve remedial goals. This research was conducted to demonstrate delayed gelation of colloidal silica suspensions when carbon sources were added and to prove the gelation occurs in sediments under vadose conditions. Sodium lactate, vegetable oil, ethanol, and molasses were tested as the examples of carbon source (or nutrient) amendments. The rheological properties of the silica suspensions during the gelation were characterized. The influence of silica, salinity, nutrient concentrations, and the type of nutrients was studied. The kinetics of nutrient release from silica-nutrient gel was quantified using molasses as the example, and the influence of suspension gelation time was evaluated. The injection behavior of the suspensions was investigated by monitoring their viscosity changes and the injection pressures when the suspensions were delivered into sediment columns.

  11. Soil-Moisture Retention Curves, Capillary Pressure Curves, and Mercury Porosimetry: A Theoretical and Computational Investigation of the Determination of the Geometric Properties of the Pore Space

    NASA Astrophysics Data System (ADS)

    Strand, T. E.; Wang, H. F.

    2003-12-01

    Immiscible displacement protocols have long been used to infer the geometric properties of the void space in granular porous media. The three most commonly used experimental techniques are the measurement of soil-moisture retention curves and relative permeability-capillary pressure-saturation relations, as well as mercury intrusion porosimetry experiments. A coupled theoretical and computational investigation was performed that provides insight into the limitations associated with each technique and quantifies the relationship between experimental observations and the geometric properties of the void space. It is demonstrated that the inference of the pore space geometry from both mercury porosimetry experiments and measurements of capillary pressure curves is influenced by trapping/mobilization phenomena and subject to scaling behavior. In addition, both techniques also assume that the capillary pressure at a location on the meniscus can be approximated by a pressure difference across a region or sample. For example, when performing capillary pressure measurements, the capillary pressure, taken to be the difference between the injected fluid pressure at the inlet and the defending fluid pressure at the outlet, is increased in a series of small steps and the fluid saturation is measured each time the system reaches steady. Regions of defending fluid that become entrapped by the invading fluid can be subsequently mobilized at higher flow rates (capillary pressures), contributing to a scale-dependence of the capillary pressure-saturation curve that complicates the determination of the properties of the pore space. This scale-dependence is particularly problematic for measurements performed at the core scale. Mercury porosimetry experiments are subject to similar limitations. Trapped regions of defending fluid are also present during the measurement of soil-moisture retention curves, but the effects of scaling behavior on the evaluation of the pore space properties from the immiscible displacement structure are much simpler to account for due to the control of mobilization phenomena. Some mobilization may occur due to film flow, but this can be limited by keeping time scales relatively small or exploited at longer time scales in order to quantify the rate of film flow. Computer simulations of gradient-stabilized drainage and imbibition to the (respective) equilibrium positions were performed using a pore-scale modified invasion percolation (MIP) model in order to quantify the relationship between the saturation profile and the geometric properties of the void space. These simulations are similar to the experimental measurement of soil-moisture retention curves. Results show that the equilibrium height and the width of the equilibrium fringe depend on two length scale distributions, one controlling the imbibition equilibrium structure and the other controlling the drainage structure. The equilibrium height is related to the mean value of the appropriate distribution as described by Jurin's law, and the width of the equilibrium fringe scales as a function of a combined parameter, the Bond number, Bo, divided by the coefficient of variation (cov). Simulations also demonstrate that the apparent radius distribution obtained from saturation profiles using direct inversion by Jurin's law is a subset of the actual distribution in the porous medium. The relationship between the apparent and actual radius distributions is quantified in terms of the combined parameter, Bo/cov, and the mean coordination number of the porous medium.

  12. Microvolume index of refraction determinations by interferometric backscatter

    NASA Astrophysics Data System (ADS)

    Bornhop, Darryl J.

    1995-06-01

    A new method has been applied to the determination of fluid bulk properties in small detection volumes. Through the use of an unfocused He-Ne laser beam and a cylindrical tube of capillary dimensions, relative refractive-index measurements are possible. The backscattered light from the illumination of a tube of capillary dimensions produces an interference pattern that is spatially defined and that contains information related to the bulk properties of the fluid contained in the tube. Positional changes in the intensity-modulated beam profile (interference fringes) are directly related to the refractive index of the fluid in the tube. The determination of dn/n at the 10-7 level is possible in probe volumes of 350 pL. The technique has been applied to tubes as small as 75 mu m inner diameter and as large as 1.0 mm inner diameter. No modification of the simple optical bench is required for facilitating the determination of refractive index for the complete range of tube diameters.

  13. 2D-Visualization of metabolic activity with planar optical chemical sensors (optodes)

    NASA Astrophysics Data System (ADS)

    Meier, R. J.; Liebsch, G.

    2015-12-01

    Microbia plays an outstandingly important role in many hydrologic compartments, such as e.g. the benthic community in sediments, or biologically active microorganisms in the capillary fringe, in ground water, or soil. Oxygen, pH, and CO2 are key factors and indicators for microbial activity. They can be measured using optical chemical sensors. These sensors record changing fluorescence properties of specific indicator dyes. The signals can be measured in a non-contact mode, even through transparent walls, which is important for many lab-experiments. They can measure in closed (transparent) systems, without sampling or intruding into the sample. They do not consume the analytes while measuring, are fully reversible and able to measure in non-stirred solutions. These sensors can be applied as high precision fiberoptic sensors (for profiling), robust sensor spots, or as planar sensors for 2D visualization (imaging). Imaging enables to detect thousands of measurement spots at the same time and generate 2D analyte maps over a region of interest. It allows for comparing different regions within one recorded image, visualizing spatial analyte gradients, or more important to identify hot spots of metabolic activity. We present ready-to-use portable imaging systems for the analytes oxygen, pH, and CO2. They consist of a detector unit, planar sensor foils and a software for easy data recording and evaluation. Sensors foils for various analytes and measurement ranges enable visualizing metabolic activity or analyte changes in the desired range. Dynamics of metabolic activity can be detected in one shot or over long time periods. We demonstrate the potential of this analytical technique by presenting experiments on benthic disturbance-recovery dynamics in sediments and microbial degradation of organic material in the capillary fringe. We think this technique is a new tool to further understand how microbial and geochemical processes are linked in (not solely) hydrologic systems.

  14. Pore Size Distributions Inferred from Modified Inversion Percolation Modeling of Drainage Curves

    NASA Astrophysics Data System (ADS)

    Dralus, D. E.; Wang, H. F.; Strand, T. E.; Glass, R. J.; Detwiler, R. L.

    2005-12-01

    Experiments have been conducted of drainage in sand packs. At equilibrium, the interface between the fluids forms a saturation transition fringe where the saturation decreases monotonically with height. This behavior was observed in a 1-inch thick pack of 20-30 sand contained front and back within two thin, 12-inch-by-24-inch glass plates. The translucent chamber was illuminated from behind by a bank of fluorescent bulbs. Acquired data were in the form of images captured by a CCD camera with resolution on the grain scale. The measured intensity of the transmitted light was used to calculate the average saturation at each point in the chamber. This study used a modified invasion percolation (MIP) model to simulate the drainage experiments to evaluate the relationship between the saturation-versus-height curve at equilibrium and the pore size distribution associated with the granular medium. The simplest interpretation of a drainage curve is in terms of a distribution of capillary tubes whose radii reproduce the the observed distribution of rise heights. However, this apparent radius distribution obtained from direct inversion of the saturation profile did not yield the assumed radius distribution. Further investigation demonstrated that the equilibrium height distribution is controlled primarily by the Bond number (ratio of gravity to capillary forces) with some influence from the width of the pore radius distribution. The width of the equilibrium fringe is quantified in terms of the ratio of Bond number to the standard deviation of the pore throat distribution. The normalized saturation-vs-height curves exhibit a power-law scaling behavior consistent with both Brooks-Corey and Van Genuchten type curves. Fundamental tenets of percolation theory were used to quantify the relationship between the apparent and actual radius distributions as a function of the mean coordination number and of the ratio of Bond number to standard deviation, which was supported by both MIP simulations and corresponding drainage experiments.

  15. Global patterns of groundwater table depth.

    PubMed

    Fan, Y; Li, H; Miguez-Macho, G

    2013-02-22

    Shallow groundwater affects terrestrial ecosystems by sustaining river base-flow and root-zone soil water in the absence of rain, but little is known about the global patterns of water table depth and where it provides vital support for land ecosystems. We present global observations of water table depth compiled from government archives and literature, and fill in data gaps and infer patterns and processes using a groundwater model forced by modern climate, terrain, and sea level. Patterns in water table depth explain patterns in wetlands at the global scale and vegetation gradients at regional and local scales. Overall, shallow groundwater influences 22 to 32% of global land area, including ~15% as groundwater-fed surface water features and 7 to 17% with the water table or its capillary fringe within plant rooting depths.

  16. Estimation of bare soil evaporation for different depths of water table in the wind-blown sand area of the Ordos Basin, China

    NASA Astrophysics Data System (ADS)

    Chen, Li; Wang, Wenke; Zhang, Zaiyong; Wang, Zhoufeng; Wang, Qiangmin; Zhao, Ming; Gong, Chengcheng

    2018-04-01

    Soil surface evaporation is a significant component of the hydrological cycle, occurring at the interface between the atmosphere and vadose zone, but it is affected by factors such as groundwater level, soil properties, solar radiation and others. In order to understand the soil evaporation characteristics in arid regions, a field experiment was conducted in the Ordos Basin, central China, and high accuracy sensors of soil moisture, moisture potential and temperature were installed in three field soil profiles with water-table depths (WTDs) of about 0.4, 1.4 and 2.2 m. Soil-surface-evaporation values were estimated by observed data combined with Darcy's law. Results showed that: (1) soil-surface-evaporation rate is linked to moisture content and it is also affected by air temperature. When there is sufficient moisture in the soil profile, soil evaporation increases with rising air temperature. For a WTD larger than the height of capillary rise, the soil evaporation is related to soil moisture content, and when air temperature is above 25 °C, the soil moisture content reduces quickly and the evaporation rate lowers; (2) phreatic water contributes to soil surface evaporation under conditions in which the WTD is within the capillary fringe. This indicates that phreatic water would not participate in soil evaporation for a WTD larger than the height of capillary rise. This finding developed further the understanding of phreatic evaporation, and this study provides valuable information on recognized soil evaporation processes in the arid environment.

  17. An analytical solution for predicting the transient seepage from a subsurface drainage system

    NASA Astrophysics Data System (ADS)

    Xin, Pei; Dan, Han-Cheng; Zhou, Tingzhang; Lu, Chunhui; Kong, Jun; Li, Ling

    2016-05-01

    Subsurface drainage systems have been widely used to deal with soil salinization and waterlogging problems around the world. In this paper, a mathematical model was introduced to quantify the transient behavior of the groundwater table and the seepage from a subsurface drainage system. Based on the assumption of a hydrostatic pressure distribution, the model considered the pore-water flow in both the phreatic and vadose soil zones. An approximate analytical solution for the model was derived to quantify the drainage of soils which were initially water-saturated. The analytical solution was validated against laboratory experiments and a 2-D Richards equation-based model, and found to predict well the transient water seepage from the subsurface drainage system. A saturated flow-based model was also tested and found to over-predict the time required for drainage and the total water seepage by nearly one order of magnitude, in comparison with the experimental results and the present analytical solution. During drainage, a vadose zone with a significant water storage capacity developed above the phreatic surface. A considerable amount of water still remained in the vadose zone at the steady state with the water table situated at the drain bottom. Sensitivity analyses demonstrated that effects of the vadose zone were intensified with an increased thickness of capillary fringe, capillary rise and/or burying depth of drains, in terms of the required drainage time and total water seepage. The analytical solution provides guidance for assessing the capillary effects on the effectiveness and efficiency of subsurface drainage systems for combating soil salinization and waterlogging problems.

  18. Long-distance electron transfer by cable bacteria in aquifer sediments

    PubMed Central

    Müller, Hubert; Bosch, Julian; Griebler, Christian; Damgaard, Lars Riis; Nielsen, Lars Peter; Lueders, Tillmann; Meckenstock, Rainer U

    2016-01-01

    The biodegradation of organic pollutants in aquifers is often restricted to the fringes of contaminant plumes where steep countergradients of electron donors and acceptors are separated by limited dispersive mixing. However, long-distance electron transfer (LDET) by filamentous ‘cable bacteria' has recently been discovered in marine sediments to couple spatially separated redox half reactions over centimeter scales. Here we provide primary evidence that such sulfur-oxidizing cable bacteria can also be found at oxic–anoxic interfaces in aquifer sediments, where they provide a means for the direct recycling of sulfate by electron transfer over 1–2-cm distance. Sediments were taken from a hydrocarbon-contaminated aquifer, amended with iron sulfide and saturated with water, leaving the sediment surface exposed to air. Steep geochemical gradients developed in the upper 3 cm, showing a spatial separation of oxygen and sulfide by 9 mm together with a pH profile characteristic for sulfur oxidation by LDET. Bacterial filaments, which were highly abundant in the suboxic zone, were identified by sequencing of 16S rRNA genes and fluorescence in situ hybridization (FISH) as cable bacteria belonging to the Desulfobulbaceae. The detection of similar Desulfobulbaceae at the oxic–anoxic interface of fresh sediment cores taken at a contaminated aquifer suggests that LDET may indeed be active at the capillary fringe in situ. PMID:27058505

  19. Depth dependent microbial carbon use efficiency in the capillary fringe as affected by water table fluctuations in a column incubation experiment

    NASA Astrophysics Data System (ADS)

    Pronk, G. J.; Mellage, A.; Milojevic, T.; Smeaton, C. M.; Rezanezhad, F.; Van Cappellen, P.

    2017-12-01

    Microbial growth and turnover of soil organic carbon (SOC) depend on the availability of electron donors and acceptors. The steep geochemical gradients in the capillary fringe between the saturated and unsaturated zones provide hotspots of soil microbial activity. Water table fluctuations and the associated drying and wetting cycles within these zones have been observed to lead to enhanced turnover of SOC and adaptation of the local microbial communities. To improve our understanding of SOC degradation under changing moisture conditions, we carried out an automated soil column experiment with integrated of hydro-bio-geophysical monitoring under both constant and oscillating water table conditions. An artificial soil mixture composed of quartz sand, montmorillonite, goethite and humus was used to provide a well-defined system. This material was inoculated with a microbial community extracted from a forested riparian zone. The soils were packed into 6 columns (60 cm length and 7.5 cm inner diameter) to a height of 45 cm; and three replicate columns were incubated under constant water table while another three were saturated and drained monthly. The initial soil development, carbon cycling and microbial community development were then characterized during 10 months of incubation. This system provides an ideal artificial gradient from the saturated to the unsaturated zone to study soil development from initially homogeneous materials and the same microbial community composition under controlled conditions. Depth profiles of SOC and microbial biomass after 329 days of incubation showed a depletion of carbon in the transition drying and wetting zone that was not associated with higher accumulation of microbial biomass, indicating a lower carbon use efficiency of the microbial community established within the water table fluctuation zone. This was supported by a higher ATP to microbial biomass carbon ratio within the same zone. The findings from this study highlight the importance of considering the effects of transient soil moisture and oxygen availability on microbial mediated SOC transformations. The effects of these changes in carbon use efficiency need to be included in soil models in order to accurately predict SOC turnover.

  20. Mineral formation and organo-mineral controls on the bioavailability of carbon at the terrestrial-aquatic interface

    NASA Astrophysics Data System (ADS)

    Rod, K. A.; Smith, A. P.; Renslow, R.

    2016-12-01

    Recent evidence highlights the importance of organo-mineral interactions in regulating the source or sink capacity of soil. High surface area soils, such as allophane-rich or clay-rich soils, retain organic matter (OM) via sorption to mineral surfaces which can also contribute physical isolation in interlayer spaces. Despite the direct correlation between mineral surfaces and OM accumulation, the pedogenic processes controlling the abundance of reactive surface areas and their distribution in the mineral matrix remains unclear. As global soil temperatures rise, the dissolution of primary minerals and formation of new secondary minerals may be thermodynamically favored as part of soil weathering process. Newly formed minerals can supply surfaces for organo-metallic bonding and may, therefore, stabilize OM by surface bonding and physical exclusion. This is especially relevant in environments that intersect terrestrial and aquatic systems, such as the capillary fringe zone in riparian ecosystems. To test the mechanisms of mineral surface area protection of OM, we facilitated secondary precipitation of alumino-silicates in the presence of OM held at two different temperatures in natural Nisqually River sediments (Mt Rainier, WA). This was a three month reaction intended to simulate early pedogenesis. To tease out the influence of mineral surface area increase during pedogenesis, we incubated the sediments at two different soil moisture contents to induce biodegradation. We measured OM desorption, biodegradation, and the molecular composition of mineral-associated OM both prior to and following the temperature manipulation. To simulate the saturation of capillary fringe sediment and associated transport and reaction of OM, column experiments were conducted using the reacted sediments. More co-precipitation was observed in the 20°C solution compared to the 4°C reacted solution suggesting that warming trends alter mineral development and may remove more OM from solution. The results from the static experiments will be used to model and predict the impacts of mineral sorption and biological activity on OM persistence in the context of dynamic saturation conditions and heterogeneous material properties.

  1. Effects of unsaturated zone on ground-water mounding

    USGS Publications Warehouse

    Sumner, D.M.; Rolston, D.E.; Marino, M.A.

    1999-01-01

    The design of infiltration basins used to dispose of treated wastewater or for aquifer recharge often requires estimation of ground-water mounding beneath the basin. However, the effect that the unsaturated zone has on water-table response to basin infiltration often has been overlooked in this estimation. A comparison was made between two methods used to estimate ground-water mounding-an analytical approach that is limited to the saturated zone and a numerical approach that incorporates both the saturated and the unsaturated zones. Results indicate that the error that is introduced by a method that ignores the effects of the unsaturated zone on ground-water mounding increases as the basin-loading period is shortened; as the depth to the water table increases, with increasing subsurface anisotropy; and with the inclusion of fine-textured strata. Additionally, such a method cannot accommodate the dynamic nature of basin infiltration, the finite transmission time of the infiltration front to the water table, or the interception of the basin floor by the capillary fringe.The design of infiltration basins used to dispose of treated wastewater or for aquifer recharge often requires estimation of ground-water mounding beneath the basin. However, the effect that the unsaturated zone has on water-table response to basin infiltration often has been overlooked in this estimation. A comparison was made between two methods used to estimate ground-water mounding - an analytical approach that is limited to the saturated zone and a numerical approach that incorporates both the saturated and the unsaturated zones. Results indicate that the error that is introduced by a method that ignores the effects of the unsaturated zone on ground-water mounding increases as the basin-loading period is shortened; as the depth to the water table increases, with increasing subsurface anisotropy; and with the inclusion of fine-textured strata. Additionally, such a method cannot accommodate the dynamic nature of basin infiltration, the finite transmission time of the infiltration front to the water, or the interception of the basin floor by the capillary fringe.

  2. Multiphase flow and transport caused by spontaneous gas phase growth in the presence of dense non-aqueous phase liquid

    NASA Astrophysics Data System (ADS)

    Roy, James W.; Smith, James E.

    2007-01-01

    Disconnected bubbles or ganglia of trapped gas may occur below the top of the capillary fringe through a number of mechanisms. In the presence of dense non-aqueous phase liquid (DNAPL), the disconnected gas phase experiences mass transfer of dissolved gases, including volatile components from the DNAPL. The properties of the gas phase interface can also change. This work shows for the first time that when seed gas bubbles exist spontaneous gas phase growth can be expected to occur and can significantly affect water-gas-DNAPL distributions, fluid flow, and mass transfer. Source zone behaviour was observed in three different experiments performed in a 2-dimensional flow cell. In each case, a DNAPL pool was created in a zone of larger glass beads over smaller glass beads, which served as a capillary barrier. In one experiment effluent water samples were analyzed to determine the vertical concentration profile of the plume above the pool. The experiments effectively demonstrated a) a cycle of spontaneous gas phase expansion and vertical advective mobilization of gas bubbles and ganglia above the DNAPL source zone, b) DNAPL redistribution caused by gas phase growth and mobilization, and c) that these processes can significantly affect mass transport from a NAPL source zone.

  3. Multiphase flow and transport caused by spontaneous gas phase growth in the presence of dense non-aqueous phase liquid.

    PubMed

    Roy, James W; Smith, James E

    2007-01-30

    Disconnected bubbles or ganglia of trapped gas may occur below the top of the capillary fringe through a number of mechanisms. In the presence of dense non-aqueous phase liquid (DNAPL), the disconnected gas phase experiences mass transfer of dissolved gases, including volatile components from the DNAPL. The properties of the gas phase interface can also change. This work shows for the first time that when seed gas bubbles exist spontaneous gas phase growth can be expected to occur and can significantly affect water-gas-DNAPL distributions, fluid flow, and mass transfer. Source zone behaviour was observed in three different experiments performed in a 2-dimensional flow cell. In each case, a DNAPL pool was created in a zone of larger glass beads over smaller glass beads, which served as a capillary barrier. In one experiment effluent water samples were analyzed to determine the vertical concentration profile of the plume above the pool. The experiments effectively demonstrated a) a cycle of spontaneous gas phase expansion and vertical advective mobilization of gas bubbles and ganglia above the DNAPL source zone, b) DNAPL redistribution caused by gas phase growth and mobilization, and c) that these processes can significantly affect mass transport from a NAPL source zone.

  4. Investigation on the properties of the formation and coherence of intense fringe near nonlinear medium slab

    NASA Astrophysics Data System (ADS)

    Hu, Yonghua; Qiu, Yaqiong; Li, Yang; Shi, Lin

    2018-03-01

    Near medium intense (NMI) fringe is a kind of intense fringe which can be formed near Kerr medium in high-power laser beam propagation. The formation properties of NMI fringe and the relations between NMI fringe and related important parameters are systematically investigated. It is found that it is the co-existence of two wirelike phase-typed scatterers in the incident beam spot which is mainly responsible for the high intensity of NMI fringe. From the viewpoint of coherent superposition, the formation process of NMI fringe is analyzed, and the mechanism that NMI fringe is formed by the coherent superposition of the localized bright fringes in the exit field of Kerr medium slab is demonstrated. The fluctuations of NMI fringe properties with beam wavelength, scatterer spacing and object distance are studied, the coherence of NMI fringe are revealed, and the approximate periodicity of the appearance of remarkable NMI fringe for these parameters are obtained. Especially, it is found that the intensity of NMI fringe is very sensitive to scatterer spacing. Besides, the laws about how NMI fringe properties will be changed by the modulation properties of scatterers and the medium thickness are demonstrated.

  5. High dynamic range fringe acquisition: A novel 3-D scanning technique for high-reflective surfaces

    NASA Astrophysics Data System (ADS)

    Jiang, Hongzhi; Zhao, Huijie; Li, Xudong

    2012-10-01

    This paper presents a novel 3-D scanning technique for high-reflective surfaces based on phase-shifting fringe projection method. High dynamic range fringe acquisition (HDRFA) technique is developed to process the fringe images reflected from the shiny surfaces, and generates a synthetic fringe image by fusing the raw fringe patterns, acquired with different camera exposure time and the illumination fringe intensity from the projector. Fringe image fusion algorithm is introduced to avoid saturation and under-illumination phenomenon by choosing the pixels in the raw fringes with the highest fringe modulation intensity. A method of auto-selection of HDRFA parameters is developed and largely increases the measurement automation. The synthetic fringes have higher signal-to-noise ratio (SNR) under ambient light by optimizing HDRFA parameters. Experimental results show that the proposed technique can successfully measure objects with high-reflective surfaces and is insensitive to ambient light.

  6. Identifying data gaps and prioritizing restoration strategies for Fremont cottonwood using linked geomorphic and population models

    NASA Astrophysics Data System (ADS)

    Harper, E. B.; Stella, J. C.; Fremier, A. K.

    2009-12-01

    Fremont cottonwood (Populus fremontii) is an important component of semi-arid riparian ecosystems throughout western North America, but its populations are in decline due to flow regulation. Achieving a balance between human resource needs and riparian ecosystem function requires a mechanistic understanding of the multiple geomorphic and biological factors affecting tree recruitment and survival, including the timing and magnitude of river flows, and the concomitant influence on suitable habitat creation and mortality from scour and sedimentation burial. Despite a great deal of empirical research on some components of the system, such as factors affecting cottonwood recruitment, other key components are less studied. Yet understanding the relative influence of the full suite of physical and life-history drivers is critical to modeling whole-population dynamics under changing environmental conditions. We addressed these issues for the Fremont cottonwood population along the Sacramento River, CA using a sensitivity analysis approach to quantify uncertainty in parameters on the outcomes of a patch-based, dynamic population model. Using a broad range of plausible values for 15 model parameters that represent key physical, biological and climatic components of the ecosystem, we ran 1,000 population simulations that consisted of a subset of 14.3 million possible combinations of parameter estimates to predict the frequency of patch colonization and total forest habitat predicted to occur under current hydrologic conditions after 175 years. Results indicate that Fremont cottonwood populations are highly sensitive to the interactions among flow regime, sedimentation rate and the depth of the capillary fringe (Fig. 1). Estimates of long-term floodplain sedimentation rate would substantially improve model accuracy. Spatial variation in sediment texture was also important to the extent that it determines the depth of the capillary fringe, which regulates the availability of water for germination and adult tree growth. Our sensitivity analyses suggest that models of future scenarios should incorporate regional climate change projections because changes in temperature and the timing and volume of precipitation affects sensitive aspects of the system, including the timing of seed release and spring snowmelt runoff. Figure 1. The relative effects on model predictions of uncertainty around each parameter included in the patch-based population model for Fremont cottonwood.

  7. Generalized spin filtering and an improved derivative-sign binary image method for the extraction of fringe skeletons

    NASA Astrophysics Data System (ADS)

    Yu, Qifeng; Liu, Xiaolin; Sun, Xiangyi

    1998-07-01

    Generalized spin filters, including several directional filters such as the directional median filter and the directional binary filter, are proposed for removal of the noise of fringe patterns and the extraction of fringe skeletons with the help of fringe-orientation maps (FOM s). The generalized spin filters can filter off noise on fringe patterns and binary fringe patterns efficiently, without distortion of fringe features. A quadrantal angle filter is developed to filter off the FOM. With these new filters, the derivative-sign binary image (DSBI) method for extraction of fringe skeletons is improved considerably. The improved DSBI method can extract high-density skeletons as well as common density skeletons.

  8. Fringe pattern demodulation with a two-frame digital phase-locked loop algorithm.

    PubMed

    Gdeisat, Munther A; Burton, David R; Lalor, Michael J

    2002-09-10

    A novel technique called a two-frame digital phase-locked loop for fringe pattern demodulation is presented. In this scheme, two fringe patterns with different spatial carrier frequencies are grabbed for an object. A digital phase-locked loop algorithm tracks and demodulates the phase difference between both fringe patterns by employing the wrapped phase components of one of the fringe patterns as a reference to demodulate the second fringe pattern. The desired phase information can be extracted from the demodulated phase difference. We tested the algorithm experimentally using real fringe patterns. The technique is shown to be suitable for noncontact measurement of objects with rapid surface variations, and it outperforms the Fourier fringe analysis technique in this aspect. Phase maps produced withthis algorithm are noisy in comparison with phase maps generated with the Fourier fringe analysis technique.

  9. Interactive Fringe Analysis System: Applications To Moire Contourogram And Interferogram

    NASA Astrophysics Data System (ADS)

    Yatagai, T.; Idesawa, M.; Yamaashi, Y.; Suzuki, M.

    1982-10-01

    A general purpose fringe pattern processing facility was developed in order to analyze moire photographs used for scoliosis diagnoses and interferometric patterns in optical shops. A TV camera reads a fringe profile to be analyzed, and peaks of the fringe are detected by a microcomputer. Fringe peak correction and fringe order determination are performed with the man-machine interactive software developed. A light pen facility and an image digitizer are employed for interaction. In the case of two-dimensional fringe analysis, we analyze independently analysis lines parallel to each other and a reference line perpendicular to the parallel analysis lines. Fringe orders of parallel analysis lines are uniquely determined by using the fringe order of the reference line. Some results of analysis of moire contourograms, interferometric testing of silicon wafers, and holographic measurement of thermal deformation are presented.

  10. 49 CFR 25.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Fringe benefits. 25.525 Section 25.525... Employment in Education Programs or Activities Prohibited § 25.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  11. 49 CFR 25.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 1 2012-10-01 2012-10-01 false Fringe benefits. 25.525 Section 25.525... Employment in Education Programs or Activities Prohibited § 25.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  12. 49 CFR 25.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 1 2011-10-01 2011-10-01 false Fringe benefits. 25.525 Section 25.525... Employment in Education Programs or Activities Prohibited § 25.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  13. 49 CFR 25.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 1 2014-10-01 2014-10-01 false Fringe benefits. 25.525 Section 25.525... Employment in Education Programs or Activities Prohibited § 25.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  14. Dual-sensitivity profilometry with defocused projection of binary fringes.

    PubMed

    Garnica, G; Padilla, M; Servin, M

    2017-10-01

    A dual-sensitivity profilometry technique based on defocused projection of binary fringes is presented. Here, two sets of fringe patterns with a sinusoidal profile are produced by applying the same analog low-pass filter (projector defocusing) to binary fringes with a high- and low-frequency spatial carrier. The high-frequency fringes have a binary square-wave profile, while the low-frequency binary fringes are produced with error-diffusion dithering. The binary nature of the binary fringes removes the need for calibration of the projector's nonlinear gamma. Working with high-frequency carrier fringes, we obtain a high-quality wrapped phase. On the other hand, working with low-frequency carrier fringes we found a lower-quality, nonwrapped phase map. The nonwrapped estimation is used as stepping stone for dual-sensitivity temporal phase unwrapping, extending the applicability of the technique to discontinuous (piecewise continuous) surfaces. We are proposing a single defocusing level for faster high- and low-frequency fringe data acquisition. The proposed technique is validated with experimental results.

  15. 10 CFR 1042.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Fringe benefits. 1042.525 Section 1042.525 Energy... Education Programs or Activities Prohibited § 1042.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life...

  16. 36 CFR 1211.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 3 2011-07-01 2011-07-01 false Fringe benefits. 1211.525... Prohibited § 1211.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

  17. 22 CFR 146.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Fringe benefits. 146.525 Section 146.525... Employment in Education Programs or Activities Prohibited § 146.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  18. 44 CFR 19.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 44 Emergency Management and Assistance 1 2013-10-01 2013-10-01 false Fringe benefits. 19.525... Programs or Activities Prohibited § 19.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or...

  19. 22 CFR 146.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Fringe benefits. 146.525 Section 146.525... Employment in Education Programs or Activities Prohibited § 146.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  20. 22 CFR 229.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Fringe benefits. 229.525 Section 229.525... Employment in Education Programs or Activities Prohibited § 229.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  1. 22 CFR 229.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Fringe benefits. 229.525 Section 229.525... Employment in Education Programs or Activities Prohibited § 229.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  2. 44 CFR 19.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Fringe benefits. 19.525... Programs or Activities Prohibited § 19.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or...

  3. 36 CFR 1211.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 3 2012-07-01 2012-07-01 false Fringe benefits. 1211.525... Prohibited § 1211.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

  4. 44 CFR 19.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 44 Emergency Management and Assistance 1 2012-10-01 2011-10-01 true Fringe benefits. 19.525... Programs or Activities Prohibited § 19.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or...

  5. 36 CFR 1211.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Fringe benefits. 1211.525... Prohibited § 1211.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

  6. 28 CFR 54.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 2 2014-07-01 2014-07-01 false Fringe benefits. 54.525 Section 54.525... in Employment in Education Programs or Activities Prohibited § 54.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  7. 10 CFR 1042.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Fringe benefits. 1042.525 Section 1042.525 Energy... Education Programs or Activities Prohibited § 1042.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life...

  8. 32 CFR 196.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 2 2012-07-01 2012-07-01 false Fringe benefits. 196.525 Section 196.525... Prohibited § 196.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

  9. 22 CFR 229.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Fringe benefits. 229.525 Section 229.525... Employment in Education Programs or Activities Prohibited § 229.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  10. 22 CFR 229.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Fringe benefits. 229.525 Section 229.525... Employment in Education Programs or Activities Prohibited § 229.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  11. 32 CFR 196.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 2 2011-07-01 2011-07-01 false Fringe benefits. 196.525 Section 196.525... Prohibited § 196.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

  12. 36 CFR 1211.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false Fringe benefits. 1211.525... Prohibited § 1211.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

  13. 22 CFR 146.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Fringe benefits. 146.525 Section 146.525... Employment in Education Programs or Activities Prohibited § 146.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  14. 28 CFR 54.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Fringe benefits. 54.525 Section 54.525... in Employment in Education Programs or Activities Prohibited § 54.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  15. 44 CFR 19.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 44 Emergency Management and Assistance 1 2014-10-01 2014-10-01 false Fringe benefits. 19.525... Programs or Activities Prohibited § 19.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or...

  16. 32 CFR 196.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Fringe benefits. 196.525 Section 196.525... Prohibited § 196.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

  17. 28 CFR 54.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 2 2012-07-01 2012-07-01 false Fringe benefits. 54.525 Section 54.525... in Employment in Education Programs or Activities Prohibited § 54.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  18. 22 CFR 146.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Fringe benefits. 146.525 Section 146.525... Employment in Education Programs or Activities Prohibited § 146.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  19. 22 CFR 229.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Fringe benefits. 229.525 Section 229.525... Employment in Education Programs or Activities Prohibited § 229.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  20. 32 CFR 196.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 2 2014-07-01 2014-07-01 false Fringe benefits. 196.525 Section 196.525... Prohibited § 196.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

  1. 28 CFR 54.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 28 Judicial Administration 2 2011-07-01 2011-07-01 false Fringe benefits. 54.525 Section 54.525... in Employment in Education Programs or Activities Prohibited § 54.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  2. 10 CFR 1042.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Fringe benefits. 1042.525 Section 1042.525 Energy... Education Programs or Activities Prohibited § 1042.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life...

  3. 22 CFR 146.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Fringe benefits. 146.525 Section 146.525... Employment in Education Programs or Activities Prohibited § 146.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  4. 32 CFR 196.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 2 2013-07-01 2013-07-01 false Fringe benefits. 196.525 Section 196.525... Prohibited § 196.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

  5. 44 CFR 19.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 44 Emergency Management and Assistance 1 2011-10-01 2011-10-01 false Fringe benefits. 19.525... Programs or Activities Prohibited § 19.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or...

  6. 10 CFR 1042.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Fringe benefits. 1042.525 Section 1042.525 Energy... Education Programs or Activities Prohibited § 1042.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life...

  7. 10 CFR 1042.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Fringe benefits. 1042.525 Section 1042.525 Energy... Education Programs or Activities Prohibited § 1042.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life...

  8. 31 CFR 28.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance: Treasury 1 2014-07-01 2014-07-01 false Fringe benefits. 28.525 Section 28... the Basis of Sex in Employment in Education Programs or Activities Prohibited § 28.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any...

  9. 6 CFR 17.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 6 Domestic Security 1 2014-01-01 2014-01-01 false Fringe benefits. 17.525 Section 17.525 Domestic... in Employment in Education Programs or Activities Prohibited § 17.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, the term fringe benefits means any medical...

  10. 40 CFR 5.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 1 2012-07-01 2012-07-01 false Fringe benefits. 5.525 Section 5.525... in Employment in Education Programs or Activities Prohibited § 5.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  11. 29 CFR 36.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Fringe benefits. 36.525 Section 36.525 Labor Office of the... Activities Prohibited § 36.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

  12. 41 CFR 101-4.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 2 2013-07-01 2012-07-01 true Fringe benefits. 101-4... in Employment in Education Programs or Activities Prohibited § 101-4.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  13. 43 CFR 41.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Fringe benefits. 41.525 Section 41.525... in Employment in Education Programs or Activities Prohibited § 41.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  14. 43 CFR 41.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Fringe benefits. 41.525 Section 41.525... in Employment in Education Programs or Activities Prohibited § 41.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  15. 14 CFR 1253.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Fringe benefits. 1253.525 Section 1253.525... in Employment in Education Programs or Activities Prohibited § 1253.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  16. 41 CFR 101-4.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 2 2012-07-01 2012-07-01 false Fringe benefits. 101-4... in Employment in Education Programs or Activities Prohibited § 101-4.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  17. 31 CFR 28.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance: Treasury 1 2012-07-01 2012-07-01 false Fringe benefits. 28.525 Section 28... the Basis of Sex in Employment in Education Programs or Activities Prohibited § 28.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any...

  18. 10 CFR 5.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Fringe benefits. 5.525 Section 5.525 Energy NUCLEAR... Activities Prohibited § 5.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

  19. 31 CFR 28.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance: Treasury 1 2011-07-01 2011-07-01 false Fringe benefits. 28.525 Section 28... the Basis of Sex in Employment in Education Programs or Activities Prohibited § 28.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any...

  20. 45 CFR 86.56 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 1 2014-10-01 2014-10-01 false Fringe benefits. 86.56 Section 86.56 Public... Basis of Sex in Employment in Education Programs or Activities Prohibited § 86.56 Fringe benefits. (a) Fringe benefits defined. For purposes of this part, fringe benefits means: Any medical, hospital...

  1. 40 CFR 5.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 1 2011-07-01 2011-07-01 false Fringe benefits. 5.525 Section 5.525... in Employment in Education Programs or Activities Prohibited § 5.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  2. 41 CFR 101-4.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Fringe benefits. 101-4... in Employment in Education Programs or Activities Prohibited § 101-4.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  3. 45 CFR 86.56 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 1 2012-10-01 2012-10-01 false Fringe benefits. 86.56 Section 86.56 Public... Basis of Sex in Employment in Education Programs or Activities Prohibited § 86.56 Fringe benefits. (a) Fringe benefits defined. For purposes of this part, fringe benefits means: Any medical, hospital...

  4. 45 CFR 86.56 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 1 2011-10-01 2011-10-01 false Fringe benefits. 86.56 Section 86.56 Public... Basis of Sex in Employment in Education Programs or Activities Prohibited § 86.56 Fringe benefits. (a) Fringe benefits defined. For purposes of this part, fringe benefits means: Any medical, hospital...

  5. 29 CFR 36.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 1 2013-07-01 2013-07-01 false Fringe benefits. 36.525 Section 36.525 Labor Office of the... Activities Prohibited § 36.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

  6. 41 CFR 101-4.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 41 Public Contracts and Property Management 2 2014-07-01 2012-07-01 true Fringe benefits. 101-4... in Employment in Education Programs or Activities Prohibited § 101-4.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  7. 10 CFR 5.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Fringe benefits. 5.525 Section 5.525 Energy NUCLEAR... Activities Prohibited § 5.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

  8. 45 CFR 86.56 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 1 2013-10-01 2013-10-01 false Fringe benefits. 86.56 Section 86.56 Public... Basis of Sex in Employment in Education Programs or Activities Prohibited § 86.56 Fringe benefits. (a) Fringe benefits defined. For purposes of this part, fringe benefits means: Any medical, hospital...

  9. 36 CFR § 1211.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 3 2013-07-01 2012-07-01 true Fringe benefits. § 1211.525... Prohibited § 1211.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

  10. 10 CFR 5.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Fringe benefits. 5.525 Section 5.525 Energy NUCLEAR... Activities Prohibited § 5.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

  11. 31 CFR 28.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Fringe benefits. 28.525 Section 28... the Basis of Sex in Employment in Education Programs or Activities Prohibited § 28.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any...

  12. 10 CFR 5.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Fringe benefits. 5.525 Section 5.525 Energy NUCLEAR... Activities Prohibited § 5.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

  13. 14 CFR 1253.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Fringe benefits. 1253.525 Section 1253.525... in Employment in Education Programs or Activities Prohibited § 1253.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  14. 31 CFR 28.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance: Treasury 1 2013-07-01 2013-07-01 false Fringe benefits. 28.525 Section 28... the Basis of Sex in Employment in Education Programs or Activities Prohibited § 28.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any...

  15. 29 CFR 36.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 1 2014-07-01 2013-07-01 true Fringe benefits. 36.525 Section 36.525 Labor Office of the... Activities Prohibited § 36.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

  16. 6 CFR 17.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 6 Domestic Security 1 2011-01-01 2011-01-01 false Fringe benefits. 17.525 Section 17.525 Domestic... in Employment in Education Programs or Activities Prohibited § 17.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, the term fringe benefits means any medical...

  17. 14 CFR 1253.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 5 2013-01-01 2013-01-01 false Fringe benefits. 1253.525 Section 1253.525... in Employment in Education Programs or Activities Prohibited § 1253.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  18. 10 CFR 5.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Fringe benefits. 5.525 Section 5.525 Energy NUCLEAR... Activities Prohibited § 5.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit...

  19. 45 CFR 86.56 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Fringe benefits. 86.56 Section 86.56 Public... Basis of Sex in Employment in Education Programs or Activities Prohibited § 86.56 Fringe benefits. (a) Fringe benefits defined. For purposes of this part, fringe benefits means: Any medical, hospital...

  20. 43 CFR 41.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Fringe benefits. 41.525 Section 41.525... in Employment in Education Programs or Activities Prohibited § 41.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  1. 14 CFR 1253.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Fringe benefits. 1253.525 Section 1253.525... in Employment in Education Programs or Activities Prohibited § 1253.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  2. 40 CFR 5.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 1 2013-07-01 2013-07-01 false Fringe benefits. 5.525 Section 5.525... in Employment in Education Programs or Activities Prohibited § 5.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  3. 6 CFR 17.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 6 Domestic Security 1 2013-01-01 2013-01-01 false Fringe benefits. 17.525 Section 17.525 Domestic... in Employment in Education Programs or Activities Prohibited § 17.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, the term fringe benefits means any medical...

  4. 6 CFR 17.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 6 Domestic Security 1 2010-01-01 2010-01-01 false Fringe benefits. 17.525 Section 17.525 Domestic... in Employment in Education Programs or Activities Prohibited § 17.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, the term fringe benefits means any medical...

  5. 6 CFR 17.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 6 Domestic Security 1 2012-01-01 2012-01-01 false Fringe benefits. 17.525 Section 17.525 Domestic... in Employment in Education Programs or Activities Prohibited § 17.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, the term fringe benefits means any medical...

  6. 43 CFR 41.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Fringe benefits. 41.525 Section 41.525... in Employment in Education Programs or Activities Prohibited § 41.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  7. 41 CFR 101-4.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 41 Public Contracts and Property Management 2 2011-07-01 2007-07-01 true Fringe benefits. 101-4... in Employment in Education Programs or Activities Prohibited § 101-4.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  8. 43 CFR 41.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Fringe benefits. 41.525 Section 41.525... in Employment in Education Programs or Activities Prohibited § 41.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  9. 40 CFR 5.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 1 2014-07-01 2014-07-01 false Fringe benefits. 5.525 Section 5.525... in Employment in Education Programs or Activities Prohibited § 5.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  10. Fringe order correction for the absolute phase recovered by two selected spatial frequency fringe projections in fringe projection profilometry.

    PubMed

    Ding, Yi; Peng, Kai; Yu, Miao; Lu, Lei; Zhao, Kun

    2017-08-01

    The performance of the two selected spatial frequency phase unwrapping methods is limited by a phase error bound beyond which errors will occur in the fringe order leading to a significant error in the recovered absolute phase map. In this paper, we propose a method to detect and correct the wrong fringe orders. Two constraints are introduced during the fringe order determination of two selected spatial frequency phase unwrapping methods. A strategy to detect and correct the wrong fringe orders is also described. Compared with the existing methods, we do not need to estimate the threshold associated with absolute phase values to determine the fringe order error, thus making it more reliable and avoiding the procedure of search in detecting and correcting successive fringe order errors. The effectiveness of the proposed method is validated by the experimental results.

  11. 15 CFR 8a.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 15 Commerce and Foreign Trade 1 2012-01-01 2012-01-01 false Fringe benefits. 8a.525 Section 8a.525... in Employment in Education Programs or Activities Prohibited § 8a.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  12. 29 CFR 5.29 - Specific fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 1 2014-07-01 2013-07-01 true Specific fringe benefits. 5.29 Section 5.29 Labor Office of... SUBJECT TO THE CONTRACT WORK HOURS AND SAFETY STANDARDS ACT) Interpretation of the Fringe Benefits Provisions of the Davis-Bacon Act § 5.29 Specific fringe benefits. (a) The act lists all types of fringe...

  13. 15 CFR 8a.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 15 Commerce and Foreign Trade 1 2013-01-01 2013-01-01 false Fringe benefits. 8a.525 Section 8a.525... in Employment in Education Programs or Activities Prohibited § 8a.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  14. 15 CFR 8a.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 1 2014-01-01 2014-01-01 false Fringe benefits. 8a.525 Section 8a.525... in Employment in Education Programs or Activities Prohibited § 8a.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  15. 26 CFR 1.61-21 - Taxation of fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 2 2013-04-01 2013-04-01 false Taxation of fringe benefits. 1.61-21 Section 1... § 1.61-21 Taxation of fringe benefits. (a) Fringe benefits—(1) In general. Section 61(a)(1) provides... includes compensation for services, including fees, commissions, fringe benefits, and similar items. For an...

  16. 15 CFR 8a.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 1 2011-01-01 2011-01-01 false Fringe benefits. 8a.525 Section 8a.525... in Employment in Education Programs or Activities Prohibited § 8a.525 Fringe benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital...

  17. Fringe-period selection for a multifrequency fringe-projection phase unwrapping method

    NASA Astrophysics Data System (ADS)

    Zhang, Chunwei; Zhao, Hong; Jiang, Kejian

    2016-08-01

    The multi-frequency fringe-projection phase unwrapping method (MFPPUM) is a typical phase unwrapping algorithm for fringe projection profilometry. It has the advantage of being capable of correctly accomplishing phase unwrapping even in the presence of surface discontinuities. If the fringe frequency ratio of the MFPPUM is too large, fringe order error (FOE) may be triggered. FOE will result in phase unwrapping error. It is preferable for the phase unwrapping to be kept correct while the fewest sets of lower frequency fringe patterns are used. To achieve this goal, in this paper a parameter called fringe order inaccuracy (FOI) is defined, dominant factors which may induce FOE are theoretically analyzed, a method to optimally select the fringe periods for the MFPPUM is proposed with the aid of FOI, and experiments are conducted to research the impact of the dominant factors in phase unwrapping and demonstrate the validity of the proposed method. Some novel phenomena are revealed by these experiments. The proposed method helps to optimally select the fringe periods and detect the phase unwrapping error for the MFPPUM.

  18. Computer-assisted techniques to evaluate fringe patterns

    NASA Astrophysics Data System (ADS)

    Sciammarella, Cesar A.; Bhat, Gopalakrishna K.

    1992-01-01

    Strain measurement using interferometry requires an efficient way to extract the desired information from interferometric fringes. Availability of digital image processing systems makes it possible to use digital techniques for the analysis of fringes. In the past, there have been several developments in the area of one dimensional and two dimensional fringe analysis techniques, including the carrier fringe method (spatial heterodyning) and the phase stepping (quasi-heterodyning) technique. This paper presents some new developments in the area of two dimensional fringe analysis, including a phase stepping technique supplemented by the carrier fringe method and a two dimensional Fourier transform method to obtain the strain directly from the discontinuous phase contour map.

  19. Comparison of infinite and wedge fringe settings in Mach Zehnder interferometer for temperature field measurement

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

    Haridas, Divya; P, Vibin Antony; Sajith, V.

    2014-10-15

    Interferometric method, which utilizes the interference of coherent light beams, is used to determine the temperature distribution in the vicinity of a vertical heater plate. The optical components are arranged so as to obtain wedge fringe and infinite fringe patterns and isotherms obtained in each case were compared. In wedge fringe setting, image processing techniques has been used for obtaining isotherms by digital subtraction of initial parallel fringe pattern from deformed fringe pattern. The experimental results obtained are compared with theoretical correlations. The merits and demerits of the fringe analysis techniques are discussed on the basis of the experimental results.

  20. A shape-preserving oriented partial differential equation based on a new fidelity term for electronic speckle pattern interferometry fringe patterns denoising

    NASA Astrophysics Data System (ADS)

    Xu, Wenjun; Tang, Chen; Zheng, Tingyue; Qiu, Yue

    2018-07-01

    Oriented partial differential equations (OPDEs) have been demonstrated to be a powerful tool for preserving the integrity of fringes while filtering electronic speckle pattern interferometry (ESPI) fringe patterns. However, the main drawback of OPDEs-based methods is that many iterations are often needed, which causes the change in the shape of fringes. Change in the shape of fringes will affect the accuracy of subsequent fringe analysis. In this paper, we focus on preserving the shape of fringes while filtering, suggested here for the first time. We propose a shape-preserving OPDE for ESPI fringe patterns denoising by introducing a new fidelity term to the previous second-order single oriented PDE (SOOPDE). In our proposed fidelity term, the evolution image is subtracted from the shrinkage result of original noisy image by shearlet transform. Our proposed shape-preserving OPDE is capable of eliminating noise effectively, keeping the integrity of fringes, and more importantly, preserving the shape of fringes. We test the proposed shape-preserving OPDE on three computer-simulated and three experimentally obtained ESPI fringe patterns with poor quality. Furthermore, we compare our model with three representative filtering methods, including the widely used SOOPDE, shearlet transform and coherence-enhancing diffusion (CED). We also compare our proposed fidelity term with the traditional fidelity term. Experimental results show that the proposed shape-preserving OPDE not only yields filtered images with visual quality on par with those by CED which is the state-of-the-art method for ESPI fringe patterns denoising, but also keeps the shape of ESPI fringe patterns.

  1. Particle measurement systems and methods

    DOEpatents

    Steele, Paul T [Livermore, CA

    2011-10-04

    A system according to one embodiment includes a light source for generating light fringes; a sampling mechanism for directing a particle through the light fringes; and at least one light detector for detecting light scattered by the particle as the particle passes through the light fringes. A method according to one embodiment includes generating light fringes using a light source; directing a particle through the light fringes; and detecting light scattered by the particle as the particle passes through the light fringes using at least one light detector.

  2. Mathematical expressions using fringe projections for transparent objects

    NASA Astrophysics Data System (ADS)

    Su, Wei-Hung; Cheng, Chau-Jern

    2017-08-01

    A setup using fringe projection techniques to perform 3D profile measurements for transparent objects is presented. The related mathematical equations are derived as well. A fringe pattern is illuminated onto the transparent object. Fringes passing through the inspected object are then projected onto a screen. A CCD camera is employed to record the transmitted fringes on the screen. Fringe on the screen are deformed by the refractive index and the surface structure, and therefore are desirable to describe the shape of the inspected sample.

  3. Analysis of Fringe Field Formed Inside LDA Measurement Volume Using Compact Two Hololens Imaging Systems

    NASA Astrophysics Data System (ADS)

    Ghosh, Abhijit; Nirala, A. K.; Yadav, H. L.

    2018-03-01

    We have designed and fabricated four LDA optical setups consisting of aberration compensated four different compact two hololens imaging systems. We have experimentally investigated and realized a hololens recording geometry which is interferogram of converging spherical wavefront with mutually coherent planar wavefront. Proposed real time monitoring and actual fringe field analysis techniques allow complete characterizations of fringes formed at measurement volume and permit to evaluate beam quality, alignment and fringe uniformity with greater precision. After experimentally analyzing the fringes formed at measurement volume by all four imaging systems, it is found that fringes obtained using compact two hololens imaging systems get improved both qualitatively and quantitatively compared to that obtained using conventional imaging system. Results indicate qualitative improvement of non-uniformity in fringe thickness and micro intensity variations perpendicular to the fringes, and quantitative improvement of 39.25% in overall average normalized standard deviations of fringe width formed by compact two hololens imaging systems compare to that of conventional imaging system.

  4. Single-shot color fringe projection for three-dimensional shape measurement of objects with discontinuities.

    PubMed

    Dai, Meiling; Yang, Fujun; He, Xiaoyuan

    2012-04-20

    A simple but effective fringe projection profilometry is proposed to measure 3D shape by using one snapshot color sinusoidal fringe pattern. One color fringe pattern encoded with a sinusoidal fringe (as red component) and one uniform intensity pattern (as blue component) is projected by a digital video projector, and the deformed fringe pattern is recorded by a color CCD camera. The captured color fringe pattern is separated into its RGB components and division operation is applied to red and blue channels to reduce the variable reflection intensity. Shape information of the tested object is decoded by applying an arcsine algorithm on the normalized fringe pattern with subpixel resolution. In the case of fringe discontinuities caused by height steps, or spatially isolated surfaces, the separated blue component is binarized and used for correcting the phase demodulation. A simple and robust method is also introduced to compensate for nonlinear intensity response of the digital video projector. The experimental results demonstrate the validity of the proposed method.

  5. Accuracy and high-speed technique for autoprocessing of Young's fringes

    NASA Astrophysics Data System (ADS)

    Chen, Wenyi; Tan, Yushan

    1991-12-01

    In this paper, an accurate and high-speed method for auto-processing of Young's fringes is proposed. A group of 1-D sampled intensity values along three or more different directions are taken from Young's fringes, and the fringe spacings of each direction are obtained by 1-D FFT respectively. Two directions that have smaller fringe spacing are selected from all directions. The accurate fringe spacings along these two directions are obtained by using orthogonal coherent phase detection technique (OCPD). The actual spacing and angle of Young's fringes, therefore, can be calculated. In this paper, the principle of OCPD is introduced in detail. The accuracy of the method is evaluated theoretically and experimentally.

  6. 29 CFR 4.171 - “Bona fide” fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 1 2014-07-01 2013-07-01 true âBona fideâ fringe benefits. 4.171 Section 4.171 Labor... Compliance with Compensation Standards § 4.171 “Bona fide” fringe benefits. (a) To be considered a “bona fide” fringe benefit for purposes of the Act, a fringe benefit plan, fund, or program must constitute a legally...

  7. On-Line Fringe Tracking and Prediction at IOTA

    NASA Technical Reports Server (NTRS)

    Wilson, Edward; Mah, Robert; Lau, Sonie (Technical Monitor)

    1999-01-01

    The Infrared/Optical Telescope Array (IOTA) is a multi-aperture Michelson interferometer located on Mt. Hopkins near Tucson, Arizona. To enable viewing of fainter targets, an on-line fringe tracking system is presently under development at NASA Ames Research Center. The system has been developed off-line using actual data from IOTA, and is presently undergoing on-line implementation at IOTA. The system has two parts: (1) a fringe tracking system that identifies the center of a fringe packet by fitting a parametric model to the data; and (2) a fringe packet motion prediction system that uses characteristics of past fringe packets to predict fringe packet motion. Combined, this information will be used to optimize on-line the scanning trajectory, resulting in improved visibility of faint targets. Fringe packet identification is highly accurate and robust (99% of the 4000 fringe packets were identified correctly, the remaining 1% were either out of the scan range or too noisy to be seen) and is performed in 30-90 milliseconds on a Pentium II-based computer. Fringe packet prediction, currently performed using an adaptive linear predictor, delivers a 10% improvement over the baseline of predicting no motion.

  8. Fringe pattern demodulation with a two-dimensional digital phase-locked loop algorithm.

    PubMed

    Gdeisat, Munther A; Burton, David R; Lalor, Michael J

    2002-09-10

    A novel technique called a two-dimensional digital phase-locked loop (DPLL) for fringe pattern demodulation is presented. This algorithm is more suitable for demodulation of fringe patterns with varying phase in two directions than the existing DPLL techniques that assume that the phase of the fringe patterns varies only in one direction. The two-dimensional DPLL technique assumes that the phase of a fringe pattern is continuous in both directions and takes advantage of the phase continuity; consequently, the algorithm has better noise performance than the existing DPLL schemes. The two-dimensional DPLL algorithm is also suitable for demodulation of fringe patterns with low sampling rates, and it outperforms the Fourier fringe analysis technique in this aspect.

  9. Computerized evaluation of holographic interferograms for fatigue crack detection in riveted lap joints

    NASA Astrophysics Data System (ADS)

    Zhou, Xiang

    Using an innovative portable holographic inspection and testing system (PHITS) developed at the Australian Defence Force Academy, fatigue cracks in riveted lap joints can be detected by visually inspecting the abnormal fringe changes recorded on holographic interferograms. In this thesis, for automatic crack detection, some modern digital image processing techniques are investigated and applied to holographic interferogram evaluation. Fringe analysis algorithms are developed for identification of the crack-induced fringe changes. Theoretical analysis of PHITS and riveted lap joints and two typical experiments demonstrate that the fatigue cracks in lightly-clamped joints induce two characteristic fringe changes: local fringe discontinuities at the cracking sites; and the global crescent fringe distribution near to the edge of the rivet hole. Both of the fringe features are used for crack detection in this thesis. As a basis of the fringe feature extraction, an algorithm for local fringe orientation calculation is proposed. For high orientation accuracy and computational efficiency, Gaussian gradient filtering and neighboring direction averaging are used to minimize the effects of image background variations and random noise. The neighboring direction averaging is also used to approximate the fringe directions in centerlines of bright and dark fringes. Experimental results indicate that for high orientation accuracy the scales of the Gaussian filter and neighboring direction averaging should be chosen according to the local fringe spacings. The orientation histogram technique is applied to detect the local fringe discontinuity due to the fatigue cracks. The Fourier descriptor technique is used to characterize the global fringe distribution change from a circular to a crescent distribution with the fatigue crack growth. Experiments and computer simulations are conducted to analyze the detectability and reliability of crack detection using the two techniques. Results demonstrate that the Fourier descriptor technique is more promising in the detection of the short cracks near the edge of the rivet head. However, it is not as reliable as the fringe orientation technique for detection of the long through cracks. For reliability, both techniques should be used in practical crack detection. Neither the Fourier descriptor technique nor the orientation histogram technique have been previously applied to holographic interferometry. While this work related primarily to interferograms of cracked rivets, the techniques would be readily applied to other areas of fringe pattern analysis.

  10. 48 CFR 731.372 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Fringe benefits. 731.372 Section 731.372 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL....372 Fringe benefits. USAID's policies on certain fringe benefits related to overseas service...

  11. 48 CFR 731.372 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Fringe benefits. 731.372 Section 731.372 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL....372 Fringe benefits. USAID's policies on certain fringe benefits related to overseas service...

  12. 48 CFR 731.372 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Fringe benefits. 731.372 Section 731.372 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL....372 Fringe benefits. USAID's policies on certain fringe benefits related to overseas service...

  13. 48 CFR 731.372 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Fringe benefits. 731.372 Section 731.372 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL....372 Fringe benefits. USAID's policies on certain fringe benefits related to overseas service...

  14. 48 CFR 731.372 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Fringe benefits. 731.372 Section 731.372 Federal Acquisition Regulations System AGENCY FOR INTERNATIONAL DEVELOPMENT GENERAL....372 Fringe benefits. USAID's policies on certain fringe benefits related to overseas service...

  15. In situ bioventing at a natural gas dehydrator site: Field demonstration

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

    Lawrence, A.W.; Miller, D.L.; Miller, J.A.

    1995-12-31

    This paper describes a bioventing/biosparging field demonstration that was conducted over a 10-month period at a former glycol dehydrator site located near Traverse City, Michigan. The goal of the project was to determine the feasibility of this technology for dehydrator site remediation and to develop engineering design concepts for applying bioventing/biosparging at similar sites. The chemicals of interest are benzene, toluene, ethylbenzene, and xylenes (BTEX) and alkanes. Soil sampling indicated that the capillary fringe and saturated zones were heavily contaminated, but that the unsaturated zone was relatively free of the contaminants. A pump-and-treat system has operated since 1991 to treatmore » the groundwater BTEX plume. Bioventing/biosparging was installed in September 1993 to treat the contaminant source area. Three different air sparging operating modes were tested to determine an optimal process configuration for site remediation. These operational modes were compared through in situ respirometry studies. Respirometry measurements were used to estimate biodegradation rates. Dissolved oxygen and carbon dioxide were monitored in the groundwater.« less

  16. Hydrologic Regulation of Plant Rooting Depth and Vice Versa

    NASA Astrophysics Data System (ADS)

    Fan, Y.; Miguez-Macho, G.

    2017-12-01

    How deep plant roots go and why may hold the answer to several questions regarding the co-evolution of terrestrial life and its environment. In this talk we explore how plant rooting depth responds to the hydrologic plumbing system in the soil/regolith/bedrocks, and vice versa. Through analyzing 2200 root observations of >1000 species along biotic (life form, genus) and abiotic (precipitation, soil, drainage) gradients, we found strong sensitivities of rooting depth to local soil water profiles determined by precipitation infiltration depth from the top (reflecting climate and soil), and groundwater table depth from below (reflecting topography-driven land drainage). In well-drained uplands, rooting depth follows infiltration depth; in waterlogged lowlands, roots stay shallow avoiding oxygen stress below the water table; in between, high productivity and drought can send roots many meters down to groundwater capillary fringe. We explore the global significance of this framework using an inverse model, and the implications to the coevolution of deep roots and the CZ in the Early-Mid Devonian when plants colonized the upland environments.

  17. Planning criteria for express bus-fringe parking operations : volume I of express bus-fringe parking planning methodology.

    DOT National Transportation Integrated Search

    1975-01-01

    Tripmaker reactions to two recent express bus-fringe parking operations in Richmond and Norfolk-Virginia Beach Virginia are examined. This travel behavior's interpreted to establish planning and design guidelines for locating and designing fringe lot...

  18. Nonlinear gamma correction via normed bicoherence minimization in optical fringe projection metrology

    NASA Astrophysics Data System (ADS)

    Kamagara, Abel; Wang, Xiangzhao; Li, Sikun

    2018-03-01

    We propose a method to compensate for the projector intensity nonlinearity induced by gamma effect in three-dimensional (3-D) fringe projection metrology by extending high-order spectra analysis and bispectral norm minimization to digital sinusoidal fringe pattern analysis. The bispectrum estimate allows extraction of vital signal information features such as spectral component correlation relationships in fringe pattern images. Our approach exploits the fact that gamma introduces high-order harmonic correlations in the affected fringe pattern image. Estimation and compensation of projector nonlinearity is realized by detecting and minimizing the normed bispectral coherence of these correlations. The proposed technique does not require calibration information and technical knowledge or specification of fringe projection unit. This is promising for developing a modular and calibration-invariant model for intensity nonlinear gamma compensation in digital fringe pattern projection profilometry. Experimental and numerical simulation results demonstrate this method to be efficient and effective in improving the phase measuring accuracies with phase-shifting fringe pattern projection profilometry.

  19. Fringing in MonoCam Y4 filter images

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

    Brooks, J.; Fisher-Levine, M.; Nomerotski, A.

    Here, we study the fringing patterns observed in MonoCam, a camera with a single Large Synoptic Survey Telescope (LSST) CCD sensor. Images were taken at the U.S. Naval Observatory in Flagstaff, Arizona (NOFS) employing its 1.3 m telescope and an LSST y4 filter. Fringing occurs due to the reflection of infrared light (700 nm or larger) from the bottom surface of the CCD which constructively or destructively interferes with the incident light to produce a net "fringe" pattern which is superimposed on all images taken. Emission lines from the atmosphere, dominated by hydroxyl (OH) spectra, can change in their relativemore » intensities as the night goes on, producing different fringe patterns in the images taken. We found through several methods that the general shape of the fringe patterns remained constant, though with slight changes in the amplitude and phase of the fringes. Lastly, we also found that a superposition of fringes from two monochromatic lines taken in the lab offered a reasonable description of the sky data.« less

  20. Fringing in MonoCam Y4 filter images

    DOE PAGES

    Brooks, J.; Fisher-Levine, M.; Nomerotski, A.

    2017-05-05

    Here, we study the fringing patterns observed in MonoCam, a camera with a single Large Synoptic Survey Telescope (LSST) CCD sensor. Images were taken at the U.S. Naval Observatory in Flagstaff, Arizona (NOFS) employing its 1.3 m telescope and an LSST y4 filter. Fringing occurs due to the reflection of infrared light (700 nm or larger) from the bottom surface of the CCD which constructively or destructively interferes with the incident light to produce a net "fringe" pattern which is superimposed on all images taken. Emission lines from the atmosphere, dominated by hydroxyl (OH) spectra, can change in their relativemore » intensities as the night goes on, producing different fringe patterns in the images taken. We found through several methods that the general shape of the fringe patterns remained constant, though with slight changes in the amplitude and phase of the fringes. Lastly, we also found that a superposition of fringes from two monochromatic lines taken in the lab offered a reasonable description of the sky data.« less

  1. Localization of Interference Fringes.

    ERIC Educational Resources Information Center

    Simon, J. M.; Comastri, Silvia A.

    1980-01-01

    Discusses a proof for determining the localized fringes position arrived at when one considers the interference of two extended sources when one is able to observe fringes only at certain points in space. Shows how the localized fringes may be found in a device used to observe Newton's rings. (Author/CS)

  2. 18 CFR 1317.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 2 2011-04-01 2011-04-01 false Fringe benefits. 1317... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  3. 24 CFR 3.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 1 2013-04-01 2013-04-01 false Fringe benefits. 3.525 Section 3... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  4. 24 CFR 3.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 1 2014-04-01 2014-04-01 false Fringe benefits. 3.525 Section 3... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  5. 45 CFR 2555.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 4 2011-10-01 2011-10-01 false Fringe benefits. 2555.525 Section 2555.525 Public... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  6. 13 CFR 113.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 13 Business Credit and Assistance 1 2013-01-01 2013-01-01 false Fringe benefits. 113.525 Section... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  7. 34 CFR 106.56 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 34 Education 1 2014-07-01 2014-07-01 false Fringe benefits. 106.56 Section 106.56 Education... benefits. (a) Fringe benefits defined. For purposes of this part, fringe benefits means: Any medical, hospital, accident, life insurance or retirement benefit, service, policy or plan, any profit-sharing or...

  8. 24 CFR 3.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 1 2012-04-01 2012-04-01 false Fringe benefits. 3.525 Section 3... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  9. 38 CFR 23.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2014-07-01 2014-07-01 false Fringe benefits. 23.525... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  10. 13 CFR 113.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 13 Business Credit and Assistance 1 2012-01-01 2012-01-01 false Fringe benefits. 113.525 Section... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  11. 34 CFR 106.56 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 34 Education 1 2013-07-01 2013-07-01 false Fringe benefits. 106.56 Section 106.56 Education... benefits. (a) Fringe benefits defined. For purposes of this part, fringe benefits means: Any medical, hospital, accident, life insurance or retirement benefit, service, policy or plan, any profit-sharing or...

  12. 45 CFR 2555.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 4 2012-10-01 2012-10-01 false Fringe benefits. 2555.525 Section 2555.525 Public... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  13. 34 CFR 106.56 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 34 Education 1 2012-07-01 2012-07-01 false Fringe benefits. 106.56 Section 106.56 Education... benefits. (a) Fringe benefits defined. For purposes of this part, fringe benefits means: Any medical, hospital, accident, life insurance or retirement benefit, service, policy or plan, any profit-sharing or...

  14. 18 CFR 1317.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Fringe benefits. 1317... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  15. 13 CFR 113.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Fringe benefits. 113.525 Section... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  16. 18 CFR 1317.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Fringe benefits. 1317... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  17. 18 CFR 1317.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Fringe benefits. 1317... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  18. 24 CFR 3.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Fringe benefits. 3.525 Section 3... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  19. 34 CFR 106.56 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 1 2011-07-01 2011-07-01 false Fringe benefits. 106.56 Section 106.56 Education... benefits. (a) Fringe benefits defined. For purposes of this part, fringe benefits means: Any medical, hospital, accident, life insurance or retirement benefit, service, policy or plan, any profit-sharing or...

  20. 34 CFR 106.56 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Fringe benefits. 106.56 Section 106.56 Education... benefits. (a) Fringe benefits defined. For purposes of this part, fringe benefits means: Any medical, hospital, accident, life insurance or retirement benefit, service, policy or plan, any profit-sharing or...

  1. 38 CFR 23.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2011-07-01 2011-07-01 false Fringe benefits. 23.525... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  2. 45 CFR 2555.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false Fringe benefits. 2555.525 Section 2555.525 Public... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  3. 45 CFR 2555.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 4 2013-10-01 2013-10-01 false Fringe benefits. 2555.525 Section 2555.525 Public... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  4. 24 CFR 3.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 1 2011-04-01 2011-04-01 false Fringe benefits. 3.525 Section 3... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  5. 38 CFR 23.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2013-07-01 2013-07-01 false Fringe benefits. 23.525... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  6. 18 CFR 1317.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Fringe benefits. 1317... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  7. 13 CFR 113.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 13 Business Credit and Assistance 1 2014-01-01 2014-01-01 false Fringe benefits. 113.525 Section... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  8. 38 CFR 23.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2012-07-01 2012-07-01 false Fringe benefits. 23.525... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  9. 13 CFR 113.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 13 Business Credit and Assistance 1 2011-01-01 2011-01-01 false Fringe benefits. 113.525 Section... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  10. 38 CFR 23.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Fringe benefits. 23.525... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  11. 45 CFR 2555.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 4 2014-10-01 2014-10-01 false Fringe benefits. 2555.525 Section 2555.525 Public... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  12. 7 CFR 15a.56 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 1 2011-01-01 2011-01-01 false Fringe benefits. 15a.56 Section 15a.56 Agriculture Office of the Secretary of Agriculture EDUCATION PROGRAMS OR ACTIVITIES RECEIVING OR BENEFITTING FROM... Activities Prohibited § 15a.56 Fringe benefits. (a) “Fringe benefits” defined. For purposes of this part...

  13. 7 CFR 15a.56 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 1 2014-01-01 2014-01-01 false Fringe benefits. 15a.56 Section 15a.56 Agriculture Office of the Secretary of Agriculture EDUCATION PROGRAMS OR ACTIVITIES RECEIVING OR BENEFITTING FROM... Activities Prohibited § 15a.56 Fringe benefits. (a) “Fringe benefits” defined. For purposes of this part...

  14. 14 CFR § 1253.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 5 2014-01-01 2014-01-01 false Fringe benefits. § 1253.525 Section Â... benefits. (a) “Fringe benefits” defined. For purposes of these Title IX regulations, fringe benefits means: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  15. 7 CFR 15a.56 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 1 2013-01-01 2013-01-01 false Fringe benefits. 15a.56 Section 15a.56 Agriculture Office of the Secretary of Agriculture EDUCATION PROGRAMS OR ACTIVITIES RECEIVING OR BENEFITTING FROM... Activities Prohibited § 15a.56 Fringe benefits. (a) “Fringe benefits” defined. For purposes of this part...

  16. 7 CFR 15a.56 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 1 2012-01-01 2012-01-01 false Fringe benefits. 15a.56 Section 15a.56 Agriculture Office of the Secretary of Agriculture EDUCATION PROGRAMS OR ACTIVITIES RECEIVING OR BENEFITTING FROM... Activities Prohibited § 15a.56 Fringe benefits. (a) “Fringe benefits” defined. For purposes of this part...

  17. 77 FR 50211 - Proposed Collection; Comment Request for Regulation Project

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-20

    ... taxation of fringe benefits and exclusions from gross income for certain fringe Benefits, listed property...-63-88 (Final and temporary regulations) Taxation of Fringe Benefits and Exclusions From Gross Income... Code section 274(d). The regulation also provides guidance on the taxation of fringe benefits and...

  18. 44 CFR 208.40 - Reimbursement of fringe benefit costs during Activation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... reimbursement sought from DHS. (c) DHS will not reimburse the Sponsoring Agency for fringe benefit costs for... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Reimbursement of fringe... RESCUE RESPONSE SYSTEM Response Cooperative Agreements § 208.40 Reimbursement of fringe benefit costs...

  19. Fringe-projection profilometry based on two-dimensional empirical mode decomposition.

    PubMed

    Zheng, Suzhen; Cao, Yiping

    2013-11-01

    In 3D shape measurement, because deformed fringes often contain low-frequency information degraded with random noise and background intensity information, a new fringe-projection profilometry is proposed based on 2D empirical mode decomposition (2D-EMD). The fringe pattern is first decomposed into numbers of intrinsic mode functions by 2D-EMD. Because the method has partial noise reduction, the background components can be removed to obtain the fundamental components needed to perform Hilbert transformation to retrieve the phase information. The 2D-EMD can effectively extract the modulation phase of a single direction fringe and an inclined fringe pattern because it is a full 2D analysis method and considers the relationship between adjacent lines of a fringe patterns. In addition, as the method does not add noise repeatedly, as does ensemble EMD, the data processing time is shortened. Computer simulations and experiments prove the feasibility of this method.

  20. 20 CFR 641.565 - What policies govern the provision of wages and fringe benefits to participants?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... covered employment. (2) Allowable fringe benefit costs. Grantees may provide the following fringe benefits... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false What policies govern the provision of wages and fringe benefits to participants? 641.565 Section 641.565 Employees' Benefits EMPLOYMENT AND...

  1. 15 CFR 8a.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Fringe benefits. 8a.525 Section 8a.525 Commerce and Foreign Trade Office of the Secretary of Commerce NONDISCRIMINATION ON THE BASIS OF SEX IN... in Employment in Education Programs or Activities Prohibited § 8a.525 Fringe benefits. (a) “Fringe...

  2. 26 CFR 1.132-9 - Qualified transportation fringes.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 2 2012-04-01 2012-04-01 false Qualified transportation fringes. 1.132-9... Qualified transportation fringes. (a) Table of contents. This section contains a list of the questions and answers in § 1.132-9. (1) General rules. Q-1. What is a qualified transportation fringe? Q-2. What is...

  3. 26 CFR 1.132-9 - Qualified transportation fringes.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 2 2014-04-01 2014-04-01 false Qualified transportation fringes. 1.132-9... Qualified transportation fringes. (a) Table of contents. This section contains a list of the questions and answers in § 1.132-9. (1) General rules. Q-1. What is a qualified transportation fringe? Q-2. What is...

  4. 26 CFR 1.132-9 - Qualified transportation fringes.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 2 2013-04-01 2013-04-01 false Qualified transportation fringes. 1.132-9... Qualified transportation fringes. (a) Table of contents. This section contains a list of the questions and answers in § 1.132-9. (1) General rules. Q-1. What is a qualified transportation fringe? Q-2. What is...

  5. Edge Triggered Apparatus and Method for Measuring Strain in Bragg Gratings

    NASA Technical Reports Server (NTRS)

    Froggatt, Mark E. (Inventor)

    2003-01-01

    An apparatus and method for measuring strain of gratings written into an optical fiber. Optical radiation is transmitted over one or more contiguous predetermined wavelength ranges into a reference optical fiber network and an optical fiber network under test to produce a plurality of reference interference fringes and measurement interference fringes, respectively. The reference and measurement fringes are detected, and the reference fringes trigger the sampling of the measurement fringes. This results in the measurement fringes being sampled at 2(pi) increments of the reference fringes. Each sampled measurement fringe of each wavelength sweep is transformed into a spatial domain waveform. The spatial domain waveforms are summed to form a summation spatial domain waveform that is used to determine location of each grating with respect to a reference reflector. A portion of each spatial domain waveform that corresponds to a particular grating is determined and transformed into a corresponding frequency spectrum representation. The strain on the grating at each wavelength of optical radiation is determined by determining the difference between the current wavelength and an earlier, zero-strain wavelength measurement.

  6. Stratigraphy and sedimentology of a dry to wet eolian depositional system, Burns formation, Meridiani Planum, Mars

    NASA Astrophysics Data System (ADS)

    Grotzinger, J. P.; Arvidson, R. E.; Bell, J. F.; Calvin, W.; Clark, B. C.; Fike, D. A.; Golombek, M.; Greeley, R.; Haldemann, A.; Herkenhoff, K. E.; Jolliff, B. L.; Knoll, A. H.; Malin, M.; McLennan, S. M.; Parker, T.; Soderblom, L.; Sohl-Dickstein, J. N.; Squyres, S. W.; Tosca, N. J.; Watters, W. A.

    2005-11-01

    Outcrop exposures of sedimentary rocks at the Opportunity landing site (Meridiani Planum) form a set of genetically related strata defined here informally as the Burns formation. This formation can be subdivided into lower, middle, and upper units which, respectively, represent eolian dune, eolian sand sheet, and mixed eolian sand sheet and interdune facies associations. Collectively, these three units are at least 7 m thick and define a "wetting-upward" succession which records a progressive increase in the influence of groundwater and, ultimately, surface water in controlling primary depositional processes. The Burns lower unit is interpreted as a dry dune field (though grain composition indicates an evaporitic source), whose preserved record of large-scale cross-bedded sandstones indicates either superimposed bedforms of variable size or reactivation of lee-side slip faces by episodic (possibly seasonal) changes in wind direction. The boundary between the lower and middle units is a significant eolian deflation surface. This surface is interpreted to record eolian erosion down to the capillary fringe of the water table, where increased resistance to wind-induced erosion was promoted by increased sediment cohesiveness in the capillary fringe. The overlying Burns middle unit is characterized by fine-scale planar-laminated to low-angle-stratified sandstones. These sandstones accumulated during lateral migration of eolian impact ripples over the flat to gently undulating sand sheet surface. In terrestrial settings, sand sheets may form an intermediate environment between dune fields and interdune or playa surfaces. The contact between the middle and upper units of the Burns formation is interpreted as a diagenetic front, where recrystallization in the phreatic or capillary zones may have occurred. The upper unit of the Burns formation contains a mixture of sand sheet facies and interdune facies. Interdune facies include wavy bedding, irregular lamination with convolute bedding and possible small tepee or salt-ridge structures, and cm-scale festoon cross-lamination indicative of shallow subaqueous flows marked by current velocities of a few tens of cm/s. Most likely, these currents were gravity-driven, possibly unchannelized flows resulting from the flooding of interdune/playa surfaces. However, evidence for lacustrine sedimentation, including mudstones or in situ bottom-growth evaporites, has not been observed so far at Eagle and Endurance craters. Mineralogical and elemental data indicate that the eolian sandstones of the lower and middle units, as well as the subaqueous and eolian deposits of the Burns upper unit, were derived from an evaporitic source. This indirectly points to a temporally equivalent playa where lacustrine evaporites or ground-water-generated efflorescent crusts were deflated to provide a source of sand-sized particles that were entrained to form eolian dunes and sand sheets. This process is responsible for the development of sulfate eolianites at White Sands, New Mexico, and could have provided a prolific flux of sulfate sediment at Meridiani. Though evidence for surface water in the Burns formation is mostly limited to the upper unit, the associated sulfate eolianites provide strong evidence for the critical role of groundwater in controlling sediment production and stratigraphic architecture throughout the formation.

  7. DLP-based 3D metrology by structured light or projected fringe technology for life sciences and industrial metrology

    NASA Astrophysics Data System (ADS)

    Frankowski, G.; Hainich, R.

    2009-02-01

    Since the mid-eighties, a fundamental idea for achieving measuring accuracy in projected fringe technology was to consider the projected fringe pattern as an interferogram and evaluate it on the basis of advanced algorithms widely used for phase measuring in real-time interferometry. A fundamental requirement for obtaining a sufficiently high degree of measuring accuracy with this so-called "phase measuring projected fringe technology" is that the projected fringes, analogous to interference fringes, must have a cos2-shaped intensity distribution. Until the mid-nineties, this requirement for the projected fringe pattern measurement technology presented a basic handicap for its wide application in 3D metrology. This situation changed abruptly, when in the nineties Texas Instruments introduced to the market advanced digital light projection on the basis of micro mirror based projection systems, socalled DLP technology, which also facilitated the generation and projection of cos2-shaped intensity and/or fringe patterns. With this DLP technology, which from its original approach was actually oriented towards completely different applications such as multimedia projection, Texas Instruments boosted phase-measuring fringe projection in optical 3D metrology to a worldwide breakthrough both for medical as well as industrial applications. A subject matter of the lecture will be to present the fundamental principles and the resulting advantages of optical 3D metrology based on phase-measuring fringe projection using DLP technology. Further will be presented and discussed applications of the measurement technology in medical engineering and industrial metrology.

  8. 24 CFR 3280.504 - Condensation control and installation of vapor retarders.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... these cavities; or (4) Homes manufactured to be sited in “humid climates” or “fringe climates” as shown on the Humid and Fringe Climate Map in this paragraph are permitted to have a vapor retarder... the humid and fringe climate areas shown on the Humid and Fringe Climate Map in paragraph (b)(4) of...

  9. 24 CFR 3280.504 - Condensation control and installation of vapor retarders.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... these cavities; or (4) Homes manufactured to be sited in “humid climates” or “fringe climates” as shown on the Humid and Fringe Climate Map in this paragraph are permitted to have a vapor retarder... the humid and fringe climate areas shown on the Humid and Fringe Climate Map in paragraph (b)(4) of...

  10. 24 CFR 3280.504 - Condensation control and installation of vapor retarders.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... be sited in “humid climates” or “fringe climates” as shown on the Humid and Fringe Climate Map in... specified), listed by state are deemed to be within the humid and fringe climate areas shown on the Humid and Fringe Climate Map in paragraph (b)(4) of this section, and the vapor retarder or construction...

  11. 24 CFR 3280.504 - Condensation control and installation of vapor retarders.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... these cavities; or (4) Homes manufactured to be sited in “humid climates” or “fringe climates” as shown on the Humid and Fringe Climate Map in this paragraph are permitted to have a vapor retarder... the humid and fringe climate areas shown on the Humid and Fringe Climate Map in paragraph (b)(4) of...

  12. Analysis of the Localization of Michelson Interferometer Fringes Using Fourier Optics and Temporal Coherence

    ERIC Educational Resources Information Center

    Narayanamurthy, C. S.

    2009-01-01

    Fringes formed in a Michelson interferometer never localize in any plane, in the detector plane and in the localization plane. Instead, the fringes are assumed to localize at infinity. Except for some explanation in "Principles of Optics" by Born and Wolf (1964 (New York: Macmillan)), the fringe localization phenomena of Michelson's interferometer…

  13. 24 CFR 3280.504 - Condensation control and installation of vapor retarders.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... these cavities; or (4) Homes manufactured to be sited in “humid climates” or “fringe climates” as shown on the Humid and Fringe Climate Map in this paragraph are permitted to have a vapor retarder... the humid and fringe climate areas shown on the Humid and Fringe Climate Map in paragraph (b)(4) of...

  14. 29 CFR 4.50 - Types of wage and fringe benefit determinations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Types of wage and fringe benefit determinations. 4.50... Determination Procedures § 4.50 Types of wage and fringe benefit determinations. The Administrator specifies the minimum monetary wages and fringe benefits to be paid as required under the Act in two types of...

  15. Fringe Benefits and the Value of Summer Leisure for Public School Teachers in the Southeast.

    ERIC Educational Resources Information Center

    Mabry, Rodney H.; And Others

    This report focuses on the fringe benefit element of total compensation for teachers in the Southeast. Study objectives include the following: (1) identifying teachers' fringe benefits in 12 Southeastern States; (2) examining the variation in fringe benefits within the region; (3) examining whether summer free time is a benefit or detriment; and…

  16. 26 CFR 1.132-6 - De minimis fringes.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 2 2014-04-01 2014-04-01 false De minimis fringes. 1.132-6 Section 1.132-6...) INCOME TAXES (CONTINUED) Items Specifically Excluded from Gross Income § 1.132-6 De minimis fringes. (a... the Internal Revenue Code of 1986 other than section 132(a)(4), the value of any fringe benefit that...

  17. 26 CFR 1.132-6 - De minimis fringes.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 2 2012-04-01 2012-04-01 false De minimis fringes. 1.132-6 Section 1.132-6...) INCOME TAXES (CONTINUED) Items Specifically Excluded from Gross Income § 1.132-6 De minimis fringes. (a... the Internal Revenue Code of 1986 other than section 132(a)(4), the value of any fringe benefit that...

  18. 26 CFR 1.132-6 - De minimis fringes.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 2 2013-04-01 2013-04-01 false De minimis fringes. 1.132-6 Section 1.132-6...) INCOME TAXES (CONTINUED) Items Specifically Excluded from Gross Income § 1.132-6 De minimis fringes. (a... the Internal Revenue Code of 1986 other than section 132(a)(4), the value of any fringe benefit that...

  19. 14 CFR 93.345 - VFR outbound procedures for fringe airports.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false VFR outbound procedures for fringe airports... Metropolitan Area Special Flight Rules Area § 93.345 VFR outbound procedures for fringe airports. (a) A pilot may depart from a fringe airport as defined in § 93.335 without filing a flight plan or communicating...

  20. 14 CFR 93.345 - VFR outbound procedures for fringe airports.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false VFR outbound procedures for fringe airports... Metropolitan Area Special Flight Rules Area § 93.345 VFR outbound procedures for fringe airports. (a) A pilot may depart from a fringe airport as defined in § 93.335 without filing a flight plan or communicating...

  1. 14 CFR 93.345 - VFR outbound procedures for fringe airports.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false VFR outbound procedures for fringe airports... Metropolitan Area Special Flight Rules Area § 93.345 VFR outbound procedures for fringe airports. (a) A pilot may depart from a fringe airport as defined in § 93.335 without filing a flight plan or communicating...

  2. 14 CFR 93.345 - VFR outbound procedures for fringe airports.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false VFR outbound procedures for fringe airports... Metropolitan Area Special Flight Rules Area § 93.345 VFR outbound procedures for fringe airports. (a) A pilot may depart from a fringe airport as defined in § 93.335 without filing a flight plan or communicating...

  3. 14 CFR 93.345 - VFR outbound procedures for fringe airports.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false VFR outbound procedures for fringe airports... Metropolitan Area Special Flight Rules Area § 93.345 VFR outbound procedures for fringe airports. (a) A pilot may depart from a fringe airport as defined in § 93.335 without filing a flight plan or communicating...

  4. Fringe stabilizers and their application to telecommunication device manufacturing

    NASA Astrophysics Data System (ADS)

    Odhner, Jefferson E.

    2000-10-01

    The ability to create stable holographic grating is an important part of the production of many telecommunication products. The stability problem is increased by the need to use ultra-violet light for close fringe spacing and long exposure times on phot-resist - a relatively low sensitivity material. Active fringe locking increases the modulation depth and efficiency of these holographic gratings. A discussion of how fringe lockers work and how they can be incorporated into a manufacturing set-up is followed by results of using fringe lockers in the manufacturing of some telecommunication devices.

  5. Analysis of the localization of Michelson interferometer fringes using Fourier optics and temporal coherence

    NASA Astrophysics Data System (ADS)

    Narayanamurthy, C. S.

    2009-01-01

    Fringes formed in a Michelson interferometer never localize in any plane, in the detector plane and in the localization plane. Instead, the fringes are assumed to localize at infinity. Except for some explanation in Principles of Optics by Born and Wolf (1964 (New York: Macmillan)), the fringe localization phenomena of Michelson's interferometer have never been analysed seriously in any book. Because Michelson's interferometer is one of the important and fundamental optical experiments taught at both undergraduate and graduate levels, it would be appropriate to explain the localization of these fringes. In this paper, we analyse the localization of Michelson interferometer fringes using Fourier optics and temporal coherence, and show that they never localize at any plane even at infinity.

  6. A Capillary Absorption Spectrometer for Stable Carbon Isotope Ratio (13C/12C) Analysis in Very Small Samples

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

    Kelly, James F.; Sams, Robert L.; Blake, Thomas A.

    2012-02-06

    A capillary absorption spectrometer (CAS) suitable for IR laser isotope analysis of small CO{sub 2} samples is presented. The system employs a continuous-wave (cw) quantum cascade laser to study nearly adjacent rovibrational transitions of different isotopologues of CO{sub 2} near 2307 cm{sup -1} (4.34 {mu}m). This initial CAS system can achieve relative isotopic precision of about 10 ppm {sup 13}C, or {approx}1{per_thousand} (per mil in delta notation relative to Vienna Pee Dee Belemnite) with 20-100 picomoles of entrained sample within the hollow waveguide for CO{sub 2} concentrations {approx}400 to 750 ppm. Isotopic analyses of such gas fills in a 1-mmmore » ID hollow waveguide of 0.8 m overall physical path length can be carried out down to {approx}2 Torr. Overall {sup 13}C/{sup 12}C ratios can be calibrated to {approx}2{per_thousand} accuracy with diluted CO{sub 2} standards. A novel, low-cost method to reduce cw-fringing noise resulting from multipath distortions in the hollow waveguide is presented, which allows weak absorbance features to be studied at the few ppm level (peak-to-rms) after 1,000 scans are co-added in {approx}10 sec. The CAS is meant to work directly with converted CO{sub 2} samples from a Laser Ablation-Catalytic-Combustion (LA CC) micro-sampler to provide {sup 13}C/{sup 12}C ratios of small biological isolates with spatial resolutions {approx}50 {mu}m.« less

  7. 26 CFR 1.61-2T - Taxation of fringe benefits-1985 through 1988 (temporary).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Taxation of fringe benefits-1985 through 1988 (temporary). 1.61-2T Section 1.61-2T Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY..., and Taxable Income § 1.61-2T Taxation of fringe benefits—1985 through 1988 (temporary). (a) Fringe...

  8. Optimized Beam Sculpting with Generalized Fringe-rate Filters

    NASA Astrophysics Data System (ADS)

    Parsons, Aaron R.; Liu, Adrian; Ali, Zaki S.; Cheng, Carina

    2016-03-01

    We generalize the technique of fringe-rate filtering, whereby visibilities measured by a radio interferometer are re-weighted according to their temporal variation. As the Earth rotates, radio sources traverse through an interferometer’s fringe pattern at rates that depend on their position on the sky. Capitalizing on this geometric interpretation of fringe rates, we employ time-domain convolution kernels to enact fringe-rate filters that sculpt the effective primary beam of antennas in an interferometer. As we show, beam sculpting through fringe-rate filtering can be used to optimize measurements for a variety of applications, including mapmaking, minimizing polarization leakage, suppressing instrumental systematics, and enhancing the sensitivity of power-spectrum measurements. We show that fringe-rate filtering arises naturally in minimum variance treatments of many of these problems, enabling optimal visibility-based approaches to analyses of interferometric data that avoid systematics potentially introduced by traditional approaches such as imaging. Our techniques have recently been demonstrated in Ali et al., where new upper limits were placed on the 21 {cm} power spectrum from reionization, showcasing the ability of fringe-rate filtering to successfully boost sensitivity and reduce the impact of systematics in deep observations.

  9. Interference Fringes of Solar Acoustic Waves around Sunspots

    NASA Astrophysics Data System (ADS)

    Chou, Dean-Yi; Zhao, Hui; Yang, Ming-Hsu; Liang, Zhi-Chao

    2012-10-01

    Solar acoustic waves are scattered by a sunspot due to the interaction between the acoustic waves and the sunspot. The sunspot, excited by the incident wave, generates the scattered wave. The scattered wave is added to the incident wave to form the total wave around the sunspot. The interference fringes between the scattered wave and the incident wave are visible in the intensity of the total wave because the coherent time of the incident wave is of the order of a wave period. The strength of the interference fringes anti-correlates with the width of temporal spectra of the incident wave. The separation between neighboring fringes increases with the incident wavelength and the sunspot size. The strength of the fringes increases with the radial order n of the incident wave from n = 0 to n = 2, and then decreases from n = 2 to n = 5. The interference fringes play a role analogous to holograms in optics. This study suggests the feasibility of using the interference fringes to reconstruct the scattered wavefields of the sunspot, although the quality of the reconstructed wavefields is sensitive to the noise and errors in the interference fringes.

  10. Phase-stepped fringe projection by rotation about the camera's perspective center.

    PubMed

    Huddart, Y R; Valera, J D; Weston, N J; Featherstone, T C; Moore, A J

    2011-09-12

    A technique to produce phase steps in a fringe projection system for shape measurement is presented. Phase steps are produced by introducing relative rotation between the object and the fringe projection probe (comprising a projector and camera) about the camera's perspective center. Relative motion of the object in the camera image can be compensated, because it is independent of the distance of the object from the camera, whilst the phase of the projected fringes is stepped due to the motion of the projector with respect to the object. The technique was validated with a static fringe projection system by moving an object on a coordinate measuring machine (CMM). The alternative approach, of rotating a lightweight and robust CMM-mounted fringe projection probe, is discussed. An experimental accuracy of approximately 1.5% of the projected fringe pitch was achieved, limited by the standard phase-stepping algorithms used rather than by the accuracy of the phase steps produced by the new technique.

  11. Fringes in FTIR spectroscopy revisited: understanding and modelling fringes in infrared spectroscopy of thin films.

    PubMed

    Konevskikh, Tatiana; Ponossov, Arkadi; Blümel, Reinhold; Lukacs, Rozalia; Kohler, Achim

    2015-06-21

    The appearance of fringes in the infrared spectroscopy of thin films seriously hinders the interpretation of chemical bands because fringes change the relative peak heights of chemical spectral bands. Thus, for the correct interpretation of chemical absorption bands, physical properties need to be separated from chemical characteristics. In the paper at hand we revisit the theory of the scattering of infrared radiation at thin absorbing films. Although, in general, scattering and absorption are connected by a complex refractive index, we show that for the scattering of infrared radiation at thin biological films, fringes and chemical absorbance can in good approximation be treated as additive. We further introduce a model-based pre-processing technique for separating fringes from chemical absorbance by extended multiplicative signal correction (EMSC). The technique is validated by simulated and experimental FTIR spectra. It is further shown that EMSC, as opposed to other suggested filtering methods for the removal of fringes, does not remove information related to chemical absorption.

  12. Metacognition and Mindfulness: the Role of Fringe Consciousness.

    PubMed

    Norman, Elisabeth

    2017-01-01

    The involvement of metacognition in mindfulness is already acknowledged in recent mindfulness models. The focus of the current paper is on how mindfulness may be seen to involve a particular subcategory of metacognitive feeling referred to as fringe consciousness . Fringe feelings are in themselves consciously experienced but have been demonstrated to reflect nonconscious context information and are assumed to play a functional role in metacognitive monitoring and behavioral control. I first address ways in which metaexperiences during mindfulness may be seen as a variety of fringe consciousness. I then turn to how mindfulness practice may change a person's attitude to fringe feelings, which in turn may influence the ease with which currently unconscious cognitive content may be retrieved. Finally, I specifically discuss how feelings of novelty , described by many as characteristic of a mindful state, may be understood within the fringe consciousness framework. I propose that fringe consciousness may be a useful framework for understanding the relationship between cognition and certain forms of subjective feelings during mindfulness.

  13. Isochromatic photoelasticity fringe patterns of PMMA in various shapes and stress applications

    NASA Astrophysics Data System (ADS)

    Manjit, Y.; Limpichaipanit, A.; Ngamjarurojana, A.

    2018-03-01

    The research focuses on isochromatic photoelastic fringe patterns in solid materials by using reflection mode in dark field polariscope. The optical setup consists of light source, polarizers, quarter wave plates, 577 nm optical pass filter, compensator and digital camera system. The fringe patterns were produced on the sample and fractional / integer number of fringe order was observed using Babinet compensator and digital camera system. The samples were circular and rectangular shape of PMMA coated with silver spray and compressed by hydraulic system at the top and the bottom. The results of the isochromatic fringe pattern were analyzed in horizontal and vertical positions. It was found that force and the number of isochromatic photoelastic fringe order depended on shape of sample, which reflects stress distribution behavior.

  14. Fast fringe pattern phase demodulation using FIR Hilbert transformers

    NASA Astrophysics Data System (ADS)

    Gdeisat, Munther; Burton, David; Lilley, Francis; Arevalillo-Herráez, Miguel

    2016-01-01

    This paper suggests the use of FIR Hilbert transformers to extract the phase of fringe patterns. This method is computationally faster than any known spatial method that produces wrapped phase maps. Also, the algorithm does not require any parameters to be adjusted which are dependent upon the specific fringe pattern that is being processed, or upon the particular setup of the optical fringe projection system that is being used. It is therefore particularly suitable for full algorithmic automation. The accuracy and validity of the suggested method has been tested using both computer-generated and real fringe patterns. This novel algorithm has been proposed for its advantages in terms of computational processing speed as it is the fastest available method to extract the wrapped phase information from a fringe pattern.

  15. Estimation of Phase in Fringe Projection Technique Using High-order Instantaneous Moments Based Method

    NASA Astrophysics Data System (ADS)

    Gorthi, Sai Siva; Rajshekhar, G.; Rastogi, Pramod

    2010-04-01

    For three-dimensional (3D) shape measurement using fringe projection techniques, the information about the 3D shape of an object is encoded in the phase of a recorded fringe pattern. The paper proposes a high-order instantaneous moments based method to estimate phase from a single fringe pattern in fringe projection. The proposed method works by approximating the phase as a piece-wise polynomial and subsequently determining the polynomial coefficients using high-order instantaneous moments to construct the polynomial phase. Simulation results are presented to show the method's potential.

  16. Soot Nanostructure: Using Fringe Analysis Software on High Resolution Transmission Electron Microscopy of Carbon Soot

    NASA Technical Reports Server (NTRS)

    King, James D.

    2004-01-01

    Using high resolution transmission electron images of carbon nanotubes and carbon particles, we are able to use image analysis program to determine several carbon fringe properties, including length, separation, curvature and orientation. Results are shown in the form of histograms for each of those quantities. The combination of those measurements can give a better indication of the graphic structure within nanotubes and particles of carbon and can distinguish carbons based upon fringe properties. Carbon with longer, straighter and closer spaced fringes are considered graphite, while amorphous carbon contain shorter, less structured fringes.

  17. Fringe Formation in Dual-Hologram Interferometry

    NASA Technical Reports Server (NTRS)

    Burner, A. W.

    1989-01-01

    A first order geometrical optics treatment of holograms combined with the generation of interference fringes by two point sources is used to describe reference fringe formation in non-diffuse dual-hologram interferometry.

  18. Grating-dot two-dimensional barcode patterns with extra binary data for encoding secret information

    NASA Astrophysics Data System (ADS)

    Lih Yeh, Sheng; Lin, Shyh Tsong

    2013-02-01

    The usual two-dimensional (2D) barcode patterns do not encrypt secret information. However, secret information is sometimes needed to increase the security features of barcode patterns. Therefore, this paper proposes 2D barcode patterns created by two-beam writers to encrypt extra binary data for encoding secret information. The proposed 2D barcode patterns are composed of many grating dots and the fringes of the grating dots are classified into four types. The first type of fringe possesses a pitch of 1.1 μm and an orientation of -45°, the second type of fringe possesses a pitch of 1.2 μm and an orientation of -45°, the third type of fringe possesses a pitch of 1.1 μm and an orientation of 45°and the fourth type of fringe possesses a pitch of 1.2 μm and an orientation of 45°. All the fringes with a 1.1 μm pitch can show a color and all the fringes with a 1.2 μm pitch can show another color when a microscope is used to inspect them. Therefore, extra binary data for encoding secret information can be formed with the two pitches. On the other hand, all the fringes with a -45° orientation can become bright for a viewing direction and all the fringes with a 45° orientation can become bright for another viewing direction when one looks at them. Therefore, the grating dots with the -45° fringe orientation and the grating dots with the 45° fringe orientation can be used to show a positive barcode image and a negative barcode image, respectively. Both the positive and negative barcode images can be used to derive the barcode data. The experiment shows that the proposed barcode patterns can be used conveniently and correctly.

  19. Regional fringe analysis for improving depth measurement in phase-shifting fringe projection profilometry

    NASA Astrophysics Data System (ADS)

    Chien, Kuang-Che Chang; Tu, Han-Yen; Hsieh, Ching-Huang; Cheng, Chau-Jern; Chang, Chun-Yen

    2018-01-01

    This study proposes a regional fringe analysis (RFA) method to detect the regions of a target object in captured shifted images to improve depth measurement in phase-shifting fringe projection profilometry (PS-FPP). In the RFA method, region-based segmentation is exploited to segment the de-fringed image of a target object, and a multi-level fuzzy-based classification with five presented features is used to analyze and discriminate the regions of an object from the segmented regions, which were associated with explicit fringe information. Then, in the experiment, the performance of the proposed method is tested and evaluated on 26 test cases made of five types of materials. The qualitative and quantitative results demonstrate that the proposed RFA method can effectively detect the desired regions of an object to improve depth measurement in the PS-FPP system.

  20. Virtual fringe projection system with nonparallel illumination based on iteration

    NASA Astrophysics Data System (ADS)

    Zhou, Duo; Wang, Zhangying; Gao, Nan; Zhang, Zonghua; Jiang, Xiangqian

    2017-06-01

    Fringe projection profilometry has been widely applied in many fields. To set up an ideal measuring system, a virtual fringe projection technique has been studied to assist in the design of hardware configurations. However, existing virtual fringe projection systems use parallel illumination and have a fixed optical framework. This paper presents a virtual fringe projection system with nonparallel illumination. Using an iterative method to calculate intersection points between rays and reference planes or object surfaces, the proposed system can simulate projected fringe patterns and captured images. A new explicit calibration method has been presented to validate the precision of the system. Simulated results indicate that the proposed iterative method outperforms previous systems. Our virtual system can be applied to error analysis, algorithm optimization, and help operators to find ideal system parameter settings for actual measurements.

  1. The Impact of Masker Fringe and Masker Sparial Uncertainty on Sound Localization

    DTIC Science & Technology

    2010-09-01

    spatial uncertainty on sound localization and to examine how such effects might be related to binaural detection and informational masking. 2 Methods...results from the binaural detection literature and suggest that a longer duration fringe provides a more robust context against which to judge the...results from the binaural detection literature, which suggest that forward masker fringe provides a greater benefit than backward masker fringe [2]. The

  2. Coherent scatter-controlled phase-change grating structures in silicon using femtosecond laser pulses.

    PubMed

    Fuentes-Edfuf, Yasser; Garcia-Lechuga, Mario; Puerto, Daniel; Florian, Camilo; Garcia-Leis, Adianez; Sanchez-Cortes, Santiago; Solis, Javier; Siegel, Jan

    2017-07-04

    Periodic structures of alternating amorphous-crystalline fringes have been fabricated in silicon using repetitive femtosecond laser exposure (800 nm wavelength and 120 fs duration). The method is based on the interference of the incident laser light with far- and near-field scattered light, leading to local melting at the interference maxima, as demonstrated by femtosecond microscopy. Exploiting this strategy, lines of highly regular amorphous fringes can be written. The fringes have been characterized in detail using optical microscopy combined modelling, which enables a determination of the three-dimensional shape of individual fringes. 2D micro-Raman spectroscopy reveals that the space between amorphous fringes remains crystalline. We demonstrate that the fringe period can be tuned over a range of 410 nm - 13 µm by changing the angle of incidence and inverting the beam scan direction. Fine control over the lateral dimensions, thickness, surface depression and optical contrast of the fringes is obtained via adjustment of pulse number, fluence and spot size. Large-area, highly homogeneous gratings composed of amorphous fringes with micrometer width and millimeter length can readily be fabricated. The here presented fabrication technique is expected to have applications in the fields of optics, nanoelectronics, and mechatronics and should be applicable to other materials.

  3. Adaptive projection intensity adjustment for avoiding saturation in three-dimensional shape measurement

    NASA Astrophysics Data System (ADS)

    Chen, Chao; Gao, Nan; Wang, Xiangjun; Zhang, Zonghua

    2018-03-01

    Phase-based fringe projection methods have been commonly used for three-dimensional (3D) measurements. However, image saturation results in incorrect intensities in captured fringe pattern images, leading to phase and measurement errors. Existing solutions are complex. This paper proposes an adaptive projection intensity adjustment method to avoid image saturation and maintain good fringe modulation in measuring objects with a high range of surface reflectivities. The adapted fringe patterns are created using only one prior step of fringe-pattern projection and image capture. First, a set of phase-shifted fringe patterns with maximum projection intensity value of 255 and a uniform gray level pattern are projected onto the surface of an object. The patterns are reflected from and deformed by the object surface and captured by a digital camera. The best projection intensities corresponding to each saturated-pixel clusters are determined by fitting a polynomial function to transform captured intensities to projected intensities. Subsequently, the adapted fringe patterns are constructed using the best projection intensities at projector pixel coordinate. Finally, the adapted fringe patterns are projected for phase recovery and 3D shape calculation. The experimental results demonstrate that the proposed method achieves high measurement accuracy even for objects with a high range of surface reflectivities.

  4. Real-time vibration measurement by a spatial phase-shifting technique with a tilted holographic interferogram.

    PubMed

    Nakadate, S; Isshiki, M

    1997-01-01

    Real-time vibration measurement by a tilted holographic interferogram is presented that utilizes the real-time digital fringe processor of a video signal. Three intensity data sampled at every one-third of the fringe spacing of the tilted fringes are used to calculate the modulation term of the fringe that is a function of a vibration amplitude. A three-dimensional lookup table performs the calculation in a TV repetition rate to give a new fringe profile that contours the vibration amplitude. Vibration modes at the resonant frequencies of a flat speaker were displayed on a monitor as changing the exciting frequency of vibration.

  5. 3D image acquisition by fiber-based fringe projection

    NASA Astrophysics Data System (ADS)

    Pfeifer, Tilo; Driessen, Sascha

    2005-02-01

    In macroscopic production processes several measuring methods are used to assure the quality of 3D parts. Definitely, one of the most widespread techniques is the fringe projection. It"s a fast and accurate method to receive the topography of a part as a computer file which can be processed in further steps, e.g. to compare the measured part to a given CAD file. In this article it will be shown how the fringe projection method is applied to a fiber-optic system. The fringes generated by a miniaturized fringe projector (MiniRot) are first projected onto the front-end of an image guide using special optics. The image guide serves as a transmitter for the fringes in order to get them onto the surface of a micro part. A second image guide is used to observe the micro part. It"s mounted under an angle relating to the illuminating image guide so that the triangulation condition is fulfilled. With a CCD camera connected to the second image guide the projected fringes are recorded and those data is analyzed by an image processing system.

  6. Modular digital holographic fringe data processing system

    NASA Technical Reports Server (NTRS)

    Downward, J. G.; Vavra, P. C.; Schebor, F. S.; Vest, C. M.

    1985-01-01

    A software architecture suitable for reducing holographic fringe data into useful engineering data is developed and tested. The results, along with a detailed description of the proposed architecture for a Modular Digital Fringe Analysis System, are presented.

  7. Effects of the Tax Treatment of Fringe Benefits on Labor Market Segmentation.

    ERIC Educational Resources Information Center

    Scott, Frank A.; And Others

    1989-01-01

    Argues that the provision of the same fringe benefits for all workers promotes labor market segmentation by inducing workers to sort themselves across the economy according to their demand for fringe benefits. (JOW)

  8. Fringe formation in dual-hologram interferometry

    NASA Technical Reports Server (NTRS)

    Burner, A. W.

    1990-01-01

    Reference-fringe formation in nondiffuse dual-hologram interferometry is described by combining a first-order geometrical hologram treatment with interference fringes generated by two point sources. The first-order imaging relationships can be used to describe reference-fringe patterns for the geometry of the dual-hologram interferometry. The process can be completed without adjusting the two holograms when the reconstructing wavelength is less than the exposing wavelength, and the process is found to facilitate basic intereferometer adjustments.

  9. A new method for determining the plasma electron density using three-color interferometer

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

    Arakawa, Hiroyuki; Kawano, Yasunori; Itami, Kiyoshi

    2012-06-15

    A new method for determining the plasma electron density using the fractional fringes on three-color interferometer is proposed. Integrated phase shift on each interferometer is derived without using the temporal history of the fractional fringes. The dependence on the fringe resolution and the electrical noise are simulated on the wavelengths of CO{sub 2} laser. Short-time integrations of the fractional fringes enhance the reliability of this method.

  10. Fringe image processing based on structured light series

    NASA Astrophysics Data System (ADS)

    Gai, Shaoyan; Da, Feipeng; Li, Hongyan

    2009-11-01

    The code analysis of the fringe image is playing a vital role in the data acquisition of structured light systems, which affects precision, computational speed and reliability of the measurement processing. According to the self-normalizing characteristic, a fringe image processing method based on structured light is proposed. In this method, a series of projective patterns is used when detecting the fringe order of the image pixels. The structured light system geometry is presented, which consist of a white light projector and a digital camera, the former projects sinusoidal fringe patterns upon the object, and the latter acquires the fringe patterns that are deformed by the object's shape. Then the binary images with distinct white and black strips can be obtained and the ability to resist image noise is improved greatly. The proposed method can be implemented easily and applied for profile measurement based on special binary code in a wide field.

  11. An improved principal component analysis based region matching method for fringe direction estimation

    NASA Astrophysics Data System (ADS)

    He, A.; Quan, C.

    2018-04-01

    The principal component analysis (PCA) and region matching combined method is effective for fringe direction estimation. However, its mask construction algorithm for region matching fails in some circumstances, and the algorithm for conversion of orientation to direction in mask areas is computationally-heavy and non-optimized. We propose an improved PCA based region matching method for the fringe direction estimation, which includes an improved and robust mask construction scheme, and a fast and optimized orientation-direction conversion algorithm for the mask areas. Along with the estimated fringe direction map, filtered fringe pattern by automatic selective reconstruction modification and enhanced fast empirical mode decomposition (ASRm-EFEMD) is used for Hilbert spiral transform (HST) to demodulate the phase. Subsequently, windowed Fourier ridge (WFR) method is used for the refinement of the phase. The robustness and effectiveness of proposed method are demonstrated by both simulated and experimental fringe patterns.

  12. Flow-dependent porosity and other biomechanical properties of mysticete baleen.

    PubMed

    Werth, Alexander J

    2013-04-01

    Despite its vital function in a highly dynamic environment, baleen is typically assumed to be a static material. Its biomechanical and material properties have not previously been explored. Thus I tested sections of baleen from bowhead whales, Balaena mysticetus, and humpback whales, Megaptera novaeangliae, alone or in groups representing miniature 'racks', in a flow tank through which water and buoyant particles circulated with variable flow velocity. Kinematic sequences were recorded through an endoscopic camera or viewing window. One set of experiments investigated particle capture; another series analyzed biomechanical behavior, including fringe spacing, movement and interaction. Baleen fringe porosity directly correlates, in a mostly linear fashion, with velocity of incident water flow. However, undulation and interaction of fringes (especially of bowheads) at higher flow velocities can decrease porosity. Fringe porosity depends on distance from the baleen plate. Porosity also varies, with fringe length, by position along the length of an individual plate. Plate orientation, which varied from 0 to 90 deg relative to water flow, is crucial in fringe spacing and particle capture. At all flow velocities, porosity is lowest with plates aligned parallel to water flow. Turbulence introduced when plates rotate perpendicular to flow (as in cross-flow filtration) increases fringe interaction, so that particles more easily strike fringes yet more readily dislodge. Baleen of bowhead whales, which feed by continuous ram filtration, differs biomechanically from that of humpbacks, which use intermittent lunge filtration. The longer, finer fringes of bowhead baleen readily form a mesh-like mat, especially at higher flow velocities, to trap tiny particles.

  13. Phase demodulation method from a single fringe pattern based on correlation with a polynomial form.

    PubMed

    Robin, Eric; Valle, Valéry; Brémand, Fabrice

    2005-12-01

    The method presented extracts the demodulated phase from only one fringe pattern. Locally, this method approaches the fringe pattern morphology with the help of a mathematical model. The degree of similarity between the mathematical model and the real fringe is estimated by minimizing a correlation function. To use an optimization process, we have chosen a polynomial form such as a mathematical model. However, the use of a polynomial form induces an identification procedure with the purpose of retrieving the demodulated phase. This method, polynomial modulated phase correlation, is tested on several examples. Its performance, in terms of speed and precision, is presented on very noised fringe patterns.

  14. Second-order oriented partial-differential equations for denoising in electronic-speckle-pattern interferometry fringes.

    PubMed

    Tang, Chen; Han, Lin; Ren, Hongwei; Zhou, Dongjian; Chang, Yiming; Wang, Xiaohang; Cui, Xiaolong

    2008-10-01

    We derive the second-order oriented partial-differential equations (PDEs) for denoising in electronic-speckle-pattern interferometry fringe patterns from two points of view. The first is based on variational methods, and the second is based on controlling diffusion direction. Our oriented PDE models make the diffusion along only the fringe orientation. The main advantage of our filtering method, based on oriented PDE models, is that it is very easy to implement compared with the published filtering methods along the fringe orientation. We demonstrate the performance of our oriented PDE models via application to two computer-simulated and experimentally obtained speckle fringes and compare with related PDE models.

  15. Digital Processing Of Young's Fringes In Speckle Photography

    NASA Astrophysics Data System (ADS)

    Chen, D. J.; Chiang, F. P.

    1989-01-01

    A new technique for fully automatic diffraction fringe measurement in point-wise speckle photograph analysis is presented in this paper. The fringe orientation and spacing are initially estimated with the help of 1-D FFT. A 2-D convolution filter is then applied to enhance the estimated image . High signal-to-noise rate (SNR) fringe pattern is achieved which makes it feasible for precise determination of the displacement components. The halo-effect is also optimally eliminated in a new way. With the computation time compared favorably with those of 2-D autocorrelation method and the iterative 2-D FFT method. High reliability and accurate determination of displacement components are achieved over a wide range of fringe density.

  16. Moire-Fringe Images of Twin Boundaries in Chemical Vapor Deposited Diamond

    DTIC Science & Technology

    1992-07-10

    Moire-Fringe Images of Twin Boundaries in Chemical Vapor Deposited Diamond IJ PERSONAL AUITHOR(S) - D. Shechtman. A. Fldman, M.D. Vaudin, and J.L...micrographs of chemical vapor deposited diamond can be interprete as Moire fringes that occur when viewing twin boundaries that are inclined to the electron...Dist J Special TECHNICAL REPORT No. 14 eca MOIRE-FRINGE IMAGES OF TWIN BOUNDARIES IN CHEMICAL VAPOR DEPOSITED DIAMOND D. Shechtman, A. Feldman, M.D

  17. Detection for flatness of large surface based on structured light

    NASA Astrophysics Data System (ADS)

    He, Wenyan; Cao, Xuedong; Long, Kuang; Peng, Zhang

    2016-09-01

    In order to get flatness of a large plane, this paper set up a measurement system, composed by Line Structured Light, imaging system, CCD, etc. Line Structured Light transmits parallel fringes at a proper angle onto the plane which is measured; the imaging system and CCD locate above the plane to catch the fringes. When the plane is perfect, CCD will catch straight fringes; however, the real plane is not perfect; according to the theory of projection, the fringes caught by CCD will be distorted by convex and concave. Extract the center of line fringes to obtain the distortion of the fringe, according to the functional relationship between the distortion of fringes and the height which is measured, then we will get flatness of the entire surface. Data from experiment approached the analysis of theory. In the simulation, the vertical resolution is 0.0075 mm per pixel when measuring a plane of 400mm×400mm, choosing the size of CCD 4096×4096, at the angle 85°. Helped by sub-pixel, the precision will get the level of submicron. There are two obvious advantages: method of surface sampling can increase the efficiency for auto-repairing of machines; considering the center of fringe is required mainly in this system, as a consequence, there is no serious demand for back light.

  18. 3D mapping of breast surface using digital fringe projection

    NASA Astrophysics Data System (ADS)

    Vairavan, Rajendaran; Retnasamy, Vithyacharan; Mohamad Shahimin, Mukhzeer; Sauli, Zaliman; Leng, Lai Siang; Wan Norhaimi, Wan Mokhzani; Marimuthu, Rajeswaran; Abdullah, Othman; Kirtsaeng, Supap

    2017-02-01

    Optical sensing technique has inherited non-contact nature for generating 3D surface mapping where its application ranges from MEMS component characterization, corrosion analysis, and vibration analysis. In particular, the digital fringe projection is utilized for 3D mapping of objects through the illumination of structured light for medical application extending from oral dental measurements, lower back deformation analysis, monitoring of scoliosis and 3D face reconstruction for biometric identification. However, the usage of digital fringe projection for 3D mapping of human breast is very minimal. Thus, this paper addresses the application of digital fringe projection for 3D mapping of breast surface based on total non-contact nature. In this work, phase shift method is utilized to perform the 3D mapping. The phase shifted fringe pattern are displayed through a digital projector onto the breast surface, and the distorted fringe patterns are captured by a CCD camera. A phase map is produced, and phase unwrapping was executed to obtain the 3D surface mapping of the breast. The surface height profile from 3D fringe projection was compared with the surface height measured by a direct method using electronic digital vernier caliper. Preliminary results showed the feasibility of digital fringe projection in providing a 3D mapping of breast and its application could be further extended for breast carcinoma detection.

  19. Investigation of Underground Hydrocarbon Leakage using Ground Penetrating Radar

    NASA Astrophysics Data System (ADS)

    Srigutomo, Wahyu; Trimadona; Agustine, Eleonora

    2016-08-01

    Ground Penetrating Radar (GPR) survey was carried out in several petroleum plants to investigate hydrocarbon contamination beneath the surface. The hydrocarbon spills are generally recognized as Light Non-Aqueous Phase Liquids (LNAPL) if the plume of leakage is distributed in the capillary fringe above the water table and as Dense Non-Aqueous Phase Liquids (DNAPL) if it is below the water table. GPR antennas of 200 MHz and 400 MHz were deployed to obtain clear radargrams until 4 m deep. In general, the interpreted radargram sections indicate the presence of surface concrete layer, the compacted silty soill followed by sand layer and the original clayey soil as well as the water table. The presence of hydrocarbon plumes are identified as shadow zones (radar velocity and intensity contrasts) in the radargram that blur the layering pattern with different intensity of reflected signal. Based on our results, the characteristic of the shadow zones in the radargram is controlled by several factors: types of hydrocarbon (fresh or bio-degraded), water moisture in the soil, and clay content which contribute variation in electrical conductivity and dielectric constants of the soil.

  20. Probing the prodigious strain fringes from Lourdes

    NASA Astrophysics Data System (ADS)

    Aerden, Domingo G. A. M.; Sayab, Mohammad

    2017-12-01

    We investigate the kinematics of classic sigmoidal strain fringes from Lourdes (France) and review previous genetic models, strain methods and strain rates for these microstructures. Displacement controlled quartz and calcite fibers within the fringes yield an average strain of 195% with the technique of Ramsay and Huber (1983). This agrees well with strains measured from boudinaged pyrite layers and calcite veins in the same rocks, but conflicts with ca. ∼675% strain in previous analogue models for the studied strain fringes produced by progressive simple shear. We show that the detailed geometry and orientation of fiber patterns are insufficiently explained by simple shear but imply two successive, differently oriented strain fields. Although all strain fringes have the same overall asymmetry, considerable morphological variation resulted from different amounts of rotation of pyrite grains and fringes. Minor rotation led to sharply kinked fibers that record a ca. 70° rotation of the kinematic frame. Larger (up to 145°) rotations, accommodated by antithetic sliding on pyrite-fringe contacts, produced more strongly and smoothly curved fibers. Combined with published Rb-Sr ages for the studied microstructures, our new strain data indicate an average strain rate of 1.41 10-15 s-1 during ca. 37 Myr. continuous growth.

  1. Polarization modeling and predictions for DKIST part 2: application of the Berreman calculus to spectral polarization fringes of beamsplitters and crystal retarders

    NASA Astrophysics Data System (ADS)

    Harrington, David M.; Snik, Frans; Keller, Christoph U.; Sueoka, Stacey R.; van Harten, Gerard

    2017-10-01

    We outline polarization fringe predictions derived from an application of the Berreman calculus for the Daniel K. Inouye Solar Telescope (DKIST) retarder optics. The DKIST retarder baseline design used six crystals, single-layer antireflection coatings, thick cover windows, and oil between all optical interfaces. This tool estimates polarization fringes and optic Mueller matrices as functions of all optical design choices. The amplitude and period of polarized fringes under design changes, manufacturing errors, tolerances, and several physical factors can now be estimated. This tool compares well with observations of fringes for data collected with the spectropolarimeter for infrared and optical regions at the Dunn Solar Telescope using bicrystalline achromatic retarders as well as laboratory tests. With this tool, we show impacts of design decisions on polarization fringes as impacted by antireflection coatings, oil refractive indices, cover window presence, and part thicknesses. This tool helped DKIST decide to remove retarder cover windows and also recommends reconsideration of coating strategies for DKIST. We anticipate this tool to be essential in designing future retarders for mitigation of polarization and intensity fringe errors in other high spectral resolution astronomical systems.

  2. Controlling Fringe Sensitivity of Electro-Optic Holography Systems Using Laser Diode Current Modulation

    NASA Technical Reports Server (NTRS)

    Bybee, Shannon J.

    2001-01-01

    Electro-Optic Holography (EOH) is a non-intrusive, laser-based, displacement measurement technique capable of static and dynamic displacement measurements. EOH is an optical interference technique in which fringe patterns that represent displacement contour maps are generated. At excessively large displacements the fringe density may be so great that individual fringes are not resolvable using typical EOH techniques. This thesis focuses on the development and implementation of a method for controlling the sensitivity of the EOH system. This method is known as Frequency Translated Electro-Optic Holography (FTEOH). It was determined that by modulating the current source of the laser diode at integer multiples of the object vibration, the fringe pattern is governed by higher order Bessel function of the first kind and the number of fringes that represent a given displacement can be controlled. The reduction of fringes is theoretically unlimited but physically limited by the frequency bandwidth of the signal generator, providing modulation to the laser diode. Although this research technique has been verified theoretically and experimentally in this thesis, due to the current laser diode capabilities it is a tedious and time consuming process to acquire data using the FTEOH technique.

  3. Polarization modeling and predictions for DKIST part 3: focal ratio and thermal dependencies of spectral polarization fringes and optic retardance

    NASA Astrophysics Data System (ADS)

    Harrington, David M.; Sueoka, Stacey R.

    2018-01-01

    Data products from high spectral resolution astronomical polarimeters are often limited by fringes. Fringes can skew derived magnetic field properties from spectropolarimetric data. Fringe removal algorithms can also corrupt the data if the fringes and object signals are too similar. For some narrow-band imaging polarimeters, fringes change the calibration retarder properties and dominate the calibration errors. Systems-level engineering tools for polarimetric instrumentation require accurate predictions of fringe amplitudes, periods for transmission, diattenuation, and retardance. The relevant instabilities caused by environmental, thermal, and optical properties can be modeled and mitigation tools developed. We create spectral polarization fringe amplitude and temporal instability predictions by applying the Berreman calculus and simple interferometric calculations to optics in beams of varying F/ number. We then apply the formalism to superachromatic six-crystal retarders in converging beams under beam thermal loading in outdoor environmental conditions for two of the world's largest observatories: the 10-m Keck telescope and the Daniel K. Inouye Solar Telescope (DKIST). DKIST will produce a 300-W optical beam, which has imposed stringent requirements on the large diameter six-crystal retarders, dichroic beamsplitters, and internal optics. DKIST retarders are used in a converging beam with F/ ratios between 8 and 62. The fringe spectral periods, amplitudes, and thermal models of retarder behavior assisted DKIST optical designs and calibration plans with future application to many astronomical spectropolarimeters. The Low Resolution Imaging Spectrograph with polarimetry instrument at Keck also uses six-crystal retarders in a converging F / 13 beam in a Cassegrain focus exposed to summit environmental conditions providing observational verification of our predictions.

  4. Real-time fringe pattern demodulation with a second-order digital phase-locked loop.

    PubMed

    Gdeisat, M A; Burton, D R; Lalor, M J

    2000-10-10

    The use of a second-order digital phase-locked loop (DPLL) to demodulate fringe patterns is presented. The second-order DPLL has better tracking ability and more noise immunity than the first-order loop. Consequently, the second-order DPLL is capable of demodulating a wider range of fringe patterns than the first-order DPLL. A basic analysis of the first- and the second-order loops is given, and a performance comparison between the first- and the second-order DPLL's in analyzing fringe patterns is presented. The implementation of the second-order loop in real time on a commercial parallel image processing system is described. Fringe patterns are grabbed and processed, and the resultant phase maps are displayed concurrently.

  5. Frequency guided methods for demodulation of a single fringe pattern.

    PubMed

    Wang, Haixia; Kemao, Qian

    2009-08-17

    Phase demodulation from a single fringe pattern is a challenging task but of interest. A frequency-guided regularized phase tracker and a frequency-guided sequential demodulation method with Levenberg-Marquardt optimization are proposed to demodulate a single fringe pattern. Demodulation path guided by the local frequency from the highest to the lowest is applied in both methods. Since critical points have low local frequency values, they are processed last so that the spurious sign problem caused by these points is avoided. These two methods can be considered as alternatives to the effective fringe follower regularized phase tracker. Demodulation results from one computer-simulated and two experimental fringe patterns using the proposed methods will be demonstrated. (c) 2009 Optical Society of America

  6. Axial resonance of periodic patterns by using a Fresnel biprism.

    PubMed

    Doblas, Ana; Saavedra, Genaro; Martinez-Corral, Manuel; Barreiro, Juan C; Sanchez-Ortiga, Emilio; Llavador, Anabel

    2013-01-01

    This paper proposes a method for the generation of high-contrast localized sinusoidal fringes with spatially noncoherent illumination and relatively high light throughput. The method, somehow similar to the classical Lau effect, is based on the use of a Fresnel biprism. It has some advantages over previous methods for the noncoherent production of interference fringes. One is the flexibility of the method, which allows the control of the fringe period by means of a simple axial shift of the biprism. Second is the rapid axial fall-off in visibility around the high-contrast fringe planes. And third is the possibility of creating fringes with increasing or with constant period as the light beam propagates. Experimental verifications of the theoretical statements are also provided.

  7. Lithography using quantum entangled particles

    NASA Technical Reports Server (NTRS)

    Williams, Colin (Inventor); Dowling, Jonathan (Inventor)

    2003-01-01

    A system of etching using quantum entangled particles to get shorter interference fringes. An interferometer is used to obtain an interference fringe. N entangled photons are input to the interferometer. This reduces the distance between interference fringes by n, where again n is the number of entangled photons.

  8. Lithography using quantum entangled particles

    NASA Technical Reports Server (NTRS)

    Williams, Colin (Inventor); Dowling, Jonathan (Inventor)

    2001-01-01

    A system of etching using quantum entangled particles to get shorter interference fringes. An interferometer is used to obtain an interference fringe. N entangled photons are input to the interferometer. This reduces the distance between interference fringes by n, where again n is the number of entangled photons.

  9. Fringe Benefits Available to Supported Employment Participants.

    ERIC Educational Resources Information Center

    West, Michael; And Others

    1990-01-01

    Examined fringe benefits available to individuals in supported employment. Found that 64 percent of supported employees received fringe benefits. Found significant differences in availability of particular benefits across employment models. Medical-health insurance coverage was available more frequently to persons in individual placement models.…

  10. Finite fringe hologram

    NASA Technical Reports Server (NTRS)

    Heflinger, L. O.

    1970-01-01

    In holographic interferometry a small movement of apparatus between exposures causes the background of the reconstructed scene to be covered with interference fringes approximately parallel to each other. The three-dimensional quality of the holographic image is allowable since a mathematical model will give the location of the fringes.

  11. A STUDY OF FRINGE BENEFITS.

    DTIC Science & Technology

    Fringe benefits as a term was coined by the War Labor Board during World War II to describe the various indirect benefits which industry had devised...trends for the future. The appendix contains an analysis of comparative costs of fringe benefits in industry and the military services. (Author)

  12. Adaptive correction to the speckle correlation fringes by using a twisted-nematic liquid-crystal display.

    PubMed

    Hack, Erwin; Gundu, Phanindra Narayan; Rastogi, Pramod

    2005-05-10

    An innovative technique for reducing speckle noise and improving the intensity profile of the speckle correlation fringes is presented. The method is based on reducing the range of the modulation intensity values of the speckle interference pattern. After the fringe pattern is corrected adaptively at each pixel, a simple morphological filtering of the fringes is sufficient to obtain smoothed fringes. The concept is presented both analytically and by simulation by using computer-generated speckle patterns. The experimental verification is performed by using an amplitude-only spatial light modulator (SLM) in a conventional electronic speckle pattern interferometry setup. The optical arrangement for tuning a commercially available LCD array for amplitude-only behavior is described. The method of feedback to the LCD SLM to modulate the intensity of the reference beam in order to reduce the modulation intensity values is explained, and the resulting fringe pattern and increase in the signal-to-noise ratio are discussed.

  13. Utilization characteristics and importance of woody biomass resources on the rural-urban fringe in botswana.

    PubMed

    Nkambwe, Musisi; Sekhwela, Mogodisheng B M

    2006-02-01

    This article examines the utilization characteristics and importance of woody biomass resources in the rural-urban fringe zones of Botswana. In the literature for Africa, attention has been given to the availability and utilization of biomass in either urban or rural environments, but the rural-urban fringe has been neglected. Within southern Africa, this neglect is not justified; the rural-urban fringe, not getting the full benefits available in urban environments in Botswana, has developed problems in woody biomass availability and utilization that require close attention. In this article, socioeconomic data on the importance of woody biomass in the Batlokwa Tribal Territory, on the rural-urban fringe of Gaborone, Botswana, were collected together with ecologic data that reveal the utilization characteristics and potential for regrowth of woody biomass. The analysis of these results show that local woody biomass is very important in the daily lives of communities in the rural-urban fringe zones and that there is a high level of harvesting. However, there is no effort in planning land use in the tribal territory to either conserve this resource or provide alternatives to its utilization. The future of woody biomass resources in Botswana's rural-urban fringe is uncertain. The investigators recommend that a comprehensive policy for the development of the rural-urban fringe consider the importance of this resource. The neglect of this resource will have far-reaching implications on the livelihoods of residents as well as the environment in this zone.

  14. 29 CFR 36.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Secretary of Labor NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in Education Programs or...) Discriminate on the basis of sex with regard to making fringe benefits available to employees or make fringe...

  15. 29 CFR 36.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Secretary of Labor NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in Education Programs or...) Discriminate on the basis of sex with regard to making fringe benefits available to employees or make fringe...

  16. Lithography system using quantum entangled photons

    NASA Technical Reports Server (NTRS)

    Williams, Colin (Inventor); Dowling, Jonathan (Inventor); della Rossa, Giovanni (Inventor)

    2002-01-01

    A system of etching using quantum entangled particles to get shorter interference fringes. An interferometer is used to obtain an interference fringe. N entangled photons are input to the interferometer. This reduces the distance between interference fringes by n, where again n is the number of entangled photons.

  17. 29 CFR 1604.9 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... OF SEX § 1604.9 Fringe benefits. (a) “Fringe benefits,” as used herein, includes medical, hospital... prohibitions against sex discrimination contained in the act. (d) It shall be an unlawful employment practice... title VIII to a charge of sex discrimination in benefits that the cost of such benefits is greater with...

  18. 26 CFR 1.132-8 - Fringe benefit nondiscrimination rules.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 2 2013-04-01 2013-04-01 false Fringe benefit nondiscrimination rules. 1.132-8... Fringe benefit nondiscrimination rules. (a) Application of nondiscrimination rules—(1) General rule. A... such benefit from his or her income unless the benefit is available on substantially the same terms to...

  19. 29 CFR 4.52 - Fringe benefit determinations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 1 2014-07-01 2013-07-01 true Fringe benefit determinations. 4.52 Section 4.52 Labor... Procedures § 4.52 Fringe benefit determinations. (a) Wage determinations issued pursuant to the Service Contract Act ordinarily contain provisions for vacation and holiday benefits prevailing in the locality. In...

  20. American Involvement in Fringe Religious Cults

    ERIC Educational Resources Information Center

    Intellect, 1977

    1977-01-01

    "Twenty million Americans are involved in fringe religious cults such as spiritualism, Hare Krishna, Scientology, and Black Gospel groups," according to anthropologist Irving Zaretsky of the University of Chicago. He recently completed a 10-year period as a participant-observer of fringe religious groups in the San Francisco Bay area and the…

  1. The Gender Pay Gap, Fringe Benefits, and Occupational Crowding.

    ERIC Educational Resources Information Center

    Solberg, Eric; Laughlin, Teresa

    1995-01-01

    In estimating earnings equations for seven occupations, when fringe benefits are excluded, women receive significantly lower wages in all but the most female-dominated occupation. Including fringe benefits makes gender significant in only one occupational category. Crowding of one gender into an occupation appears the primary determinant of the…

  2. Retrieval of phase-derivative discontinuities in digital speckle pattern interferometry fringes using the Wigner-Ville distribution

    NASA Astrophysics Data System (ADS)

    Federico, Alejandro; Kaufmann, Guillermo H.

    2004-08-01

    We evaluate the application of the Wigner-Ville distribution (WVD) to measure phase gradient maps in digital speckle pattern interferometry (DSPI), when the generated correlation fringes present phase discontinuities. The performance of the WVD method is evaluated using computer-simulated fringes. The influence of the filtering process to smooth DSPI fringes and additional drawbacks that emerge when this method is applied are discussed. A comparison with the conventional method based on the continuous wavelet transform in the stationary phase approximation is also presented.

  3. Optical interference fringe reduction in frequency-modulation spectroscopy experiments

    NASA Astrophysics Data System (ADS)

    Hjelme, Dag Roar; Neegard, Steinar; Vartdal, Erling

    1995-08-01

    We show both theoretically and experimentally that interference fringe signals can always be suppressed to improve the signal-to-noise ratio, provided that the modulation frequency is of the order of the absorption linewidth or higher. Suppression of optical interference fringes by more than 1 order of magnitude and signal-to-noise ratio enhancement of more than 13 dB is demonstrated by use of a proper choice of laser modulation frequency. A further fringe reduction of 10 dB is possible by adjustment of the local oscillator phase.

  4. Triton Southern Hemisphere

    NASA Image and Video Library

    1998-06-08

    This polar projection from NASA Voyager 2 of Triton southern hemisphere provides a view of the southern polar cap and bright equatorial fringe. The margin of the cap is scalloped and ranges in latitude from +10 degrees to -30 degrees. The bright fringe is closely associated with the cap's margin; from it, diffuse bright rays extend north-northeast for hundreds of kilometers. The bright fringe probably consists of very fresh nitrogen frost or snow, and the rays consist of bright-fringe materials that were redistributed by north-moving Coriolis-deflected winds. http://photojournal.jpl.nasa.gov/catalog/PIA00423

  5. Wavefront reversal technique for self-referencing collimation testing

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

    Hii, King Ung; Kwek, Kuan Hiang

    2010-02-01

    We present a wavefront reversal technique to produce a dual-field fringe pattern for self-referencing collimation testing in wedge-plate lateral-shear interferometry. The method requires only a suitably placed cubic beam splitter to produce two replicas of the fringe field formed by the wedge-plate lateral-shear interferometer. One of the replicas has a fringe pattern that is the reverse of the other. With these two fringe fields, the collimation testing has a built-in reference, and the detection sensitivity is twice that of a single-wedge-plate technique.

  6. Optical fringe-reflection deflectometry with bundle adjustment

    NASA Astrophysics Data System (ADS)

    Xiao, Yong-Liang; Li, Sikun; Zhang, Qican; Zhong, Jianxin; Su, Xianyu; You, Zhisheng

    2018-06-01

    Liquid crystal display (LCD) screens are located outside of a camera's field of view in fringe-reflection deflectometry. Therefore, fringes that are displayed on LCD screens are obtained through specular reflection by a fixed camera. Thus, the pose calibration between the camera and LCD screen is one of the main challenges in fringe-reflection deflectometry. A markerless planar mirror is used to reflect the LCD screen more than three times, and the fringes are mapped into the fixed camera. The geometrical calibration can be accomplished by estimating the pose between the camera and the virtual image of fringes. Considering the relation between their pose, the incidence and reflection rays can be unified in the camera frame, and a forward triangulation intersection can be operated in the camera frame to measure three-dimensional (3D) coordinates of the specular surface. In the final optimization, constraint-bundle adjustment is operated to refine simultaneously the camera intrinsic parameters, including distortion coefficients, estimated geometrical pose between the LCD screen and camera, and 3D coordinates of the specular surface, with the help of the absolute phase collinear constraint. Simulation and experiment results demonstrate that the pose calibration with planar mirror reflection is simple and feasible, and the constraint-bundle adjustment can enhance the 3D coordinate measurement accuracy in fringe-reflection deflectometry.

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

    Liao, Yubo; School of Physics and Electronic Information Science, Gannan Normal University, Ganzhou 341000; Lei, Yunfei

    An image converter tube with a magnetic lens was used to obtain static images of moiré fringes formed by electron beam. These moiré fringes are formed due to the interference between the anode mesh and the photocathode containing slits of various spatial frequencies. Moiré fringes are observed at an accelerating voltage of 3.5 kV requiring the magnetic excitation condition of ∼550 ampere-turns. Not only the features of the fringes are analyzed but also the change of fringe spacing as a function of the rotation angle is investigated. The experimental results are found well in agreement with the theoretical analysis. By changingmore » the rotation angle or adjusting the excitation condition of the magnetic lens, we were able to record parallel moiré and secondary moiré fringes too. The secondary moiré fringes can be observed in the rotation angle range of −39.5° to −50.6°. The theoretical analysis indicates that the secondary moiré is formed by the interference between the photocathode slits and the 2-D periodic structure of the anode mesh. Combining our proposed moiré method with the pulse-dilation technique may potentially open the door for future applications, in various fields including, but not limited to, ultrafast electrical pulse diagnostics.« less

  8. Observation: Leafy spurge control in western prairie fringed orchid habitat

    Treesearch

    Donald R. Kirby; Rodney G. Lym; John J. Sterling; Carolyn Hull Sieg

    2003-01-01

    The western prairie fringed orchid (Platanthera praeclara Sheviak and Bowles) is a threatened species of the tallgrass prairie. Invasion by leafy spurge (Euphorbiaes esula L.) is a serious threat to western prairie fringed orchid habitat. The obiectives of this study were to develop a herbicide treatment to control leafy spurge...

  9. 26 CFR 1.61-2T - Taxation of fringe benefits-1985 through 1988 (temporary).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... concerning the application of law in effect prior to January 1, 1985. (b) Valuation of fringe benefits—(1) In... particular fringe benefit. Thus, for example, the effect of any special relationship that may exist between... to employer-provided vehicles. Paragraph (f) provides a commuting valuation rule relating to employer...

  10. 26 CFR 1.61-2T - Taxation of fringe benefits-1985 through 1988 (temporary).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... concerning the application of law in effect prior to January 1, 1985. (b) Valuation of fringe benefits—(1) In... particular fringe benefit. Thus, for example, the effect of any special relationship that may exist between... to employer-provided vehicles. Paragraph (f) provides a commuting valuation rule relating to employer...

  11. 26 CFR 1.61-2T - Taxation of fringe benefits-1985 through 1988 (temporary).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... concerning the application of law in effect prior to January 1, 1985. (b) Valuation of fringe benefits—(1) In... particular fringe benefit. Thus, for example, the effect of any special relationship that may exist between... to employer-provided vehicles. Paragraph (f) provides a commuting valuation rule relating to employer...

  12. 26 CFR 1.61-2T - Taxation of fringe benefits-1985 through 1988 (temporary).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... concerning the application of law in effect prior to January 1, 1985. (b) Valuation of fringe benefits—(1) In... particular fringe benefit. Thus, for example, the effect of any special relationship that may exist between... to employer-provided vehicles. Paragraph (f) provides a commuting valuation rule relating to employer...

  13. Single-shot real-time three dimensional measurement based on hue-height mapping

    NASA Astrophysics Data System (ADS)

    Wan, Yingying; Cao, Yiping; Chen, Cheng; Fu, Guangkai; Wang, Yapin; Li, Chengmeng

    2018-06-01

    A single-shot three-dimensional (3D) measurement based on hue-height mapping is proposed. The color fringe pattern is encoded by three sinusoidal fringes with the same frequency but different shifting phase into red (R), green (G) and blue (B) color channels, respectively. It is found that the hue of the captured color fringe pattern on the reference plane maintains monotonic in one period even it has the color crosstalk. Thus, unlike the traditional color phase shifting technique, the hue information is utilized to decode the color fringe pattern and map to the pixels of the fringe displacement in the proposed method. Because the monotonicity of the hue is limited within one period, displacement unwrapping is proposed to obtain the continuous displacement that is finally used to map to the height distribution. This method directly utilizes the hue under the effect of color crosstalk for mapping the height so that no color calibration is involved. Also, as it requires only single shot deformed color fringe pattern, this method can be applied into the real-time or dynamic 3D measurements.

  14. Local denoising of digital speckle pattern interferometry fringes by multiplicative correlation and weighted smoothing splines.

    PubMed

    Federico, Alejandro; Kaufmann, Guillermo H

    2005-05-10

    We evaluate the use of smoothing splines with a weighted roughness measure for local denoising of the correlation fringes produced in digital speckle pattern interferometry. In particular, we also evaluate the performance of the multiplicative correlation operation between two speckle patterns that is proposed as an alternative procedure to generate the correlation fringes. It is shown that the application of a normalization algorithm to the smoothed correlation fringes reduces the excessive bias generated in the previous filtering stage. The evaluation is carried out by use of computer-simulated fringes that are generated for different average speckle sizes and intensities of the reference beam, including decorrelation effects. A comparison with filtering methods based on the continuous wavelet transform is also presented. Finally, the performance of the smoothing method in processing experimental data is illustrated.

  15. Analysis of a multi-wavelength multi-camera phase-shifting profilometric system for real-time operation

    NASA Astrophysics Data System (ADS)

    Stoykova, Elena; Gotchev, Atanas; Sainov, Ventseslav

    2011-01-01

    Real-time accomplishment of a phase-shifting profilometry through simultaneous projection and recording of fringe patterns requires a reliable phase retrieval procedure. In the present work we consider a four-wavelength multi-camera system with four sinusoidal phase gratings for pattern projection that implements a four-step algorithm. Successful operation of the system depends on overcoming two challenges which stem out from the inherent limitations of the phase-shifting algorithm, namely the demand for a sinusoidal fringe profile and the necessity to ensure equal background and contrast of fringes in the recorded fringe patterns. As a first task, we analyze the systematic errors due to the combined influence of the higher harmonics and multi-wavelength illumination in the Fresnel diffraction zone considering the case when the modulation parameters of the four gratings are different. As a second task we simulate the system performance to evaluate the degrading effect of the speckle noise and the spatially varying fringe modulation at non-uniform illumination on the overall accuracy of the profilometric measurement. We consider the case of non-correlated speckle realizations in the recorded fringe patterns due to four-wavelength illumination. Finally, we apply a phase retrieval procedure which includes normalization, background removal and denoising of the recorded fringe patterns to both simulated and measured data obtained for a dome surface.

  16. Remote ultrasound detection with a quasi-balanced confocal Fabry-Perot interferometer

    NASA Astrophysics Data System (ADS)

    Reitinger, B.; Roither, J.; Berer, T.; Hornhuber, C.; Burgholzer, P.

    2011-09-01

    In this article, we show the benefits of a quasi-balanced fringe hopping confocal Fabry-Perot interferometer (CFPI) with broadband common mode rejection ratio (CMRR) for remote ultrasound detection. In laser ultrasound, the ultrasonic information, in general, lies in the phase modulation of laser light which in this case is demodulated using the CFPI at a certain working point on a fringe. By hopping from the positive to the negative slope on the same fringe, the detected ultrasonic signals are inverted. In contrary, interference signals - such crosstalk from the generation, ghosts or noise correlated to pulse laser excitation - are not influenced and hence get rejected by subtracting the signals measured at both slopes. Hence, a minimum of two measurements is needed for common mode rejection. The fringe hopping from the positive to the negative slope is done by changing the distance of the CFPI mirrors with a precise piezoelectric-stack and a fast high-resolution digital controller. As only one photodetector with a transimpedance amplifier is needed, a high CMRR can be accomplished. The CMRR is not affected by the symmetry of the fringe but only by pulse-to-pulse energy fluctuations of the generation laser. We show that with fringe hopping and averaging the signal-to-noise ratio increases much faster than with averaging without fringe hopping. This is due to the correlation of the quasi-noise with the generation cycle.

  17. Rejection of crosstalk and noise by a quasi balanced CFPI for remote ultrasound detection

    NASA Astrophysics Data System (ADS)

    Reitinger, B.; Berer, T.; Hornhuber, C.; Burgholzer, P.

    2011-01-01

    In this paper we show the benefits of a quasi balanced fringe hopping CFPI (confocal Fabry-Pérot interferometer) with broadband CMRR (common mode rejection ratio) for remote ultrasound detection. Ultrasonic information in general lies in the phase modulation of laser light which in this case is demodulated by using the CFPI at a certain working point on a fringe. By hopping from the positive to the negative slope on the same fringe the detected ultrasonic signals are inverted. In contrary interference signals like crosstalk from the generation, ghosts, or noise correlated to pulse laser excitation are not influenced and hence get rejected by subtracting the signals from both slopes. Hence, a minimum of two measurements is needed for common mode rejection. The fringe hopping from the positive to the negative slope is done by changing the distance of the CFPI mirrors with a precise piezoelectric-stack and a fast high resolution digital controller. As only one photo-detector with a transimpedance-amplifier is needed a high CMRR can be accomplished which is not affected by the symmetry of the fringe but only by pulse to pulse energy fluctuations of the generation laser. We show that with fringe hopping and averaging the signal to noise ratio increases much faster than with averaging without fringe hopping. This is due to the correlation of the quasi-noise with the generation cycle.

  18. Phase demodulation from a single fringe pattern based on a correlation technique.

    PubMed

    Robin, Eric; Valle, Valéry

    2004-08-01

    We present a method for determining the demodulated phase from a single fringe pattern. This method, based on a correlation technique, searches in a zone of interest for the degree of similarity between a real fringe pattern and a mathematical model. This method, named modulated phase correlation, is tested with different examples.

  19. Community structure and abundance of benthic infaunal invertebrates in Maine fringing marsh ecosystems

    Treesearch

    Richard A. MacKenzie; Michele Dionne; Jeremy Miller; Michael Haas; Pamela A. Morgan

    2015-01-01

    Fringing marshes are abundant ecosystems that dominate the New England coastline. Despite their abundance, very little baseline data is available from them and few studies have documented the ecosystems services that they provide. This information is important for conservation efforts as well as for an increased understanding of how fringing marshes function compared...

  20. A Study of Fringe Benefits and Selected Salaries of California Community College Districts.

    ERIC Educational Resources Information Center

    Kern Community Coll. District, Bakersfield, CA.

    A questionnaire requesting fringe benefit and salary information was mailed to the 70 California community college districts. Data, with the 1977-78 salary schedule provided by each district, were used to determine compensation. After fringe benefit information was determined, the dollar amount for each plan was calculated at each of three salary…

  1. 29 CFR 4.177 - Discharging fringe benefit obligations by equivalent means.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... number of non-overtime hours in a year of work, to arrive at the hourly cash equivalent. This principle... 29 Labor 1 2012-07-01 2012-07-01 false Discharging fringe benefit obligations by equivalent means... obligations by equivalent means. (a) In general. (1) Section 2(a)(2) of the Act, which provides for fringe...

  2. 29 CFR 4.177 - Discharging fringe benefit obligations by equivalent means.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... number of non-overtime hours in a year of work, to arrive at the hourly cash equivalent. This principle... 29 Labor 1 2014-07-01 2013-07-01 true Discharging fringe benefit obligations by equivalent means... obligations by equivalent means. (a) In general. (1) Section 2(a)(2) of the Act, which provides for fringe...

  3. 29 CFR 4.177 - Discharging fringe benefit obligations by equivalent means.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... number of non-overtime hours in a year of work, to arrive at the hourly cash equivalent. This principle... 29 Labor 1 2011-07-01 2011-07-01 false Discharging fringe benefit obligations by equivalent means... obligations by equivalent means. (a) In general. (1) Section 2(a)(2) of the Act, which provides for fringe...

  4. 29 CFR 4.177 - Discharging fringe benefit obligations by equivalent means.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... number of non-overtime hours in a year of work, to arrive at the hourly cash equivalent. This principle... 29 Labor 1 2010-07-01 2010-07-01 true Discharging fringe benefit obligations by equivalent means... obligations by equivalent means. (a) In general. (1) Section 2(a)(2) of the Act, which provides for fringe...

  5. 29 CFR 4.177 - Discharging fringe benefit obligations by equivalent means.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... number of non-overtime hours in a year of work, to arrive at the hourly cash equivalent. This principle... 29 Labor 1 2013-07-01 2013-07-01 false Discharging fringe benefit obligations by equivalent means... obligations by equivalent means. (a) In general. (1) Section 2(a)(2) of the Act, which provides for fringe...

  6. Evolution and loss of long-fringed petals: a case study using a dated phylogeny of the snake gourds, Trichosanthes (Cucurbitaceae)

    PubMed Central

    2012-01-01

    Background The Cucurbitaceae genus Trichosanthes comprises 90–100 species that occur from India to Japan and southeast to Australia and Fiji. Most species have large white or pale yellow petals with conspicuously fringed margins, the fringes sometimes several cm long. Pollination is usually by hawkmoths. Previous molecular data for a small number of species suggested that a monophyletic Trichosanthes might include the Asian genera Gymnopetalum (four species, lacking long petal fringes) and Hodgsonia (two species with petals fringed). Here we test these groups’ relationships using a species sampling of c. 60% and 4759 nucleotides of nuclear and plastid DNA. To infer the time and direction of the geographic expansion of the Trichosanthes clade we employ molecular clock dating and statistical biogeographic reconstruction, and we also address the gain or loss of petal fringes. Results Trichosanthes is monophyletic as long as it includes Gymnopetalum, which itself is polyphyletic. The closest relative of Trichosanthes appears to be the sponge gourds, Luffa, while Hodgsonia is more distantly related. Of six morphology-based sections in Trichosanthes with more than one species, three are supported by the molecular results; two new sections appear warranted. Molecular dating and biogeographic analyses suggest an Oligocene origin of Trichosanthes in Eurasia or East Asia, followed by diversification and spread throughout the Malesian biogeographic region and into the Australian continent. Conclusions Long-fringed corollas evolved independently in Hodgsonia and Trichosanthes, followed by two losses in the latter coincident with shifts to other pollinators but not with long-distance dispersal events. Together with the Caribbean Linnaeosicyos, the Madagascan Ampelosicyos and the tropical African Telfairia, these cucurbit lineages represent an ideal system for more detailed studies of the evolution and function of petal fringes in plant-pollinator mutualisms. PMID:22759528

  7. Space-based detection of wetlands' surface water level changes from L-band SAR interferometry

    USGS Publications Warehouse

    Wdowinski, S.; Kim, S.-W.; Amelung, F.; Dixon, T.H.; Miralles-Wilhelm, F.; Sonenshein, R.

    2008-01-01

    Interferometric processing of JERS-1 L-band Synthetic Aperture Radar (SAR) data acquired over south Florida during 1993-1996 reveals detectable surface changes in the Everglades wetlands. Although our study is limited to south Florida it has implication for other large-scale wetlands, because south Florida wetlands have diverse vegetation types and both managed and natural flow environments. Our analysis reveals that interferometric coherence level is sensitive to wetland vegetation type and to the interferogram time span. Interferograms with time spans less than six months maintain phase observations for all wetland types, allowing characterization of water level changes in different wetland environments. The most noticeable changes occur between the managed and the natural flow wetlands. In the managed wetlands, fringes are organized, follow patterns related to some of the managed water control structures and have high fringe-rate. In the natural flow areas, fringes are irregular and have a low fringe-rate. The high fringe rate in managed areas reflects dynamic water topography caused by high flow rate due to gate operation. Although this organized fringe pattern is not characteristic of most large-scale wetlands, the high level of water level change enables accurate estimation of the wetland InSAR technique, which lies in the range of 5-10??cm. The irregular and low rate fringe pattern in the natural flow area reflects uninterrupted flow that diffuses water efficiently and evenly. Most of the interferograms in the natural flow area show an elongated fringe located along the transitional zone between salt- and fresh-water wetlands, reflecting water level changes due to ocean tides. ?? 2007 Elsevier Inc. All rights reserved.

  8. The shelf space and strategic placement of healthy and discretionary foods in urban, urban-fringe and rural/non-metropolitan Australian supermarkets.

    PubMed

    Cameron, Adrian J

    2018-02-01

    Supermarkets are a key influence on eating behaviours, but it is unknown if the promotion of food within stores varies on a geographic gradient from urban, to urban-fringe and non-metropolitan areas. The present study aimed to assess the shelf space and strategic placement of healthy and discretionary foods in each of urban, urban-fringe and non-metropolitan Australian supermarkets. Design/Setting In-store audits were conducted in stores from one of the two major Australian supermarket chains in urban (n 19), urban-fringe (n 20) and non-metropolitan (n 26) areas of Victoria. These audits examined selected food items (crisps/chips, chocolate, confectionery, soft drinks/sodas, fruits and vegetables) and measured the shelf space and the proportion of end-of-aisle and cash register displays containing these products. Store size was measured as the sum of aisle length. Differences in the supermarket food environment with respect to location were assessed, before and after adjustment for neighbourhood socio-economic position. The strategic placement of discretionary foods was commonly observed in all supermarkets. Adjusting for store size (larger in urban-fringe and rural areas), urban stores had greater shelf space devoted to fruits and vegetables, and less checkouts with soft drinks, than urban-fringe and rural/non-metropolitan areas. Differences remained following adjustment for neighbourhood socio-economic position. No clear pattern was observed for end-of-aisle displays, or the placement of chocolate and confectionery at checkouts. The shelf space of healthy and discretionary foods in urban-fringe and rural stores parallels the prevalence of overweight and obesity in these areas. Interventions in urban-fringe and rural stores targeting the shelf space of healthy foods and the placement of soft drinks at key displays may be useful obesity prevention initiatives.

  9. 3D silicon breast surface mapping via structured light profilometry

    NASA Astrophysics Data System (ADS)

    Vairavan, R.; Ong, N. R.; Sauli, Z.; Kirtsaeng, S.; Sakuntasathien, S.; Shahimin, M. M.; Alcain, J. B.; Lai, S. L.; Paitong, P.; Retnasamy, V.

    2017-09-01

    Digital fringe projection technique is one of the promising optical methods for 3D surface imaging as it demonstrates non contact and non invasive characteristics. The potential of this technique matches the requirement for human body evaluation, as it is vital for disease diagnosis and for treatment option selection. Thus, the digital fringe projection has addressed this requirement with its wide clinical related application and studies. However, the application of this technique for 3D surface mapping of the breast is very minimal. Hence, in this work, the application of digital fringe projection for 3D breast surface mapping is reported. Phase shift fringe projection technique was utilized to perform the 3D breast surface mapping. Maiden results have confirmed the feasibility of using the digital fringe projection method for 3D surface mapping of the breast and it can be extended for breast cancer detection.

  10. A low-cost and portable realization on fringe projection three-dimensional measurement

    NASA Astrophysics Data System (ADS)

    Xiao, Suzhi; Tao, Wei; Zhao, Hui

    2015-12-01

    Fringe projection three-dimensional measurement is widely applied in a wide range of industrial application. The traditional fringe projection system has the disadvantages of high expense, big size, and complicated calibration requirements. In this paper we introduce a low-cost and portable realization on three-dimensional measurement with Pico projector. It has the advantages of low cost, compact physical size, and flexible configuration. For the proposed fringe projection system, there is no restriction to camera and projector's relative alignment on parallelism and perpendicularity for installation. Moreover, plane-based calibration method is adopted in this paper that avoids critical requirements on calibration system such as additional gauge block or precise linear z stage. What is more, error sources existing in the proposed system are introduced in this paper. The experimental results demonstrate the feasibility of the proposed low cost and portable fringe projection system.

  11. Characterization of CNRS Fizeau wedge laser tuner

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

    Not Available

    A fringe detection and measurement system was constructed for use with the CNRS Fizeau wedge laser tuner, consisting of three circuit boards. The first board is a standard Reticon RC-100 B motherboard which is used to provide the timing, video processing, and housekeeping functions required by the Reticon RL-512 G photodiode array used in the system. The sampled and held video signal from the motherboard is processed by a second, custom-fabricated circuit board which contains a high-speed fringe detection and locating circuit. This board includes a dc level-discriminator-type fringe detector, a counter circuit to determine fringe center, a pulsed lasermore » triggering circuit, and a control circuit to operate the shutter for the He-Ne reference laser beam. The fringe center information is supplied to the third board, a commercial single board computer, which governs the data-collection process and interprets the results.« less

  12. Space beam combiner for long-baseline interferometry

    NASA Astrophysics Data System (ADS)

    Lin, Yao; Bartos, Randall D.; Korechoff, Robert P.; Shaklan, Stuart B.

    1999-04-01

    An experimental beam combiner (BC) is being developed to support the space interferometry program at the JPL. The beam combine forms the part of an interferometer where star light collected by the sidestats or telescopes is brought together to produce white light fringes, and to provide wavefront tilt information via guiding spots and beam walk information via shear spots. The assembly and alignment of the BC has been completed. The characterization test were performed under laboratory conditions with an artificial star and optical delay line. Part of each input beam was used to perform star tracking. The white light interference fringes were obtained over the selected wavelength range from 450 nm to 850 nm. A least-square fit process was used to analyze the fringe initial phase, fringe visibilities and shift errors of the optical path difference in the delay line using the dispersed white-light fringes at different OPD positions.

  13. Enhanced dual-frequency pattern scheme based on spatial-temporal fringes method

    NASA Astrophysics Data System (ADS)

    Wang, Minmin; Zhou, Canlin; Si, Shuchun; Lei, Zhenkun; Li, Xiaolei; Li, Hui; Li, YanJie

    2018-07-01

    One of the major challenges of employing a dual-frequency phase-shifting algorithm for phase retrieval is its sensitivity to noise. Yun et al proposed a dual-frequency method based on the Fourier transform profilometry, yet the low-frequency lobes are close to each other for accurate band-pass filtering. In the light of this problem, a novel dual-frequency pattern based on the spatial-temporal fringes (STF) method is developed in this paper. Three fringe patterns with two different frequencies are required. The low-frequency phase is obtained from two low-frequency fringe patterns by the STF method, so the signal lobes can be extracted accurately as they are far away from each other. The high-frequency phase is retrieved from another fringe pattern without the impact of the DC component. Simulations and experiments are conducted to demonstrate the excellent precision of the proposed method.

  14. Characterization of CNRS Fizeau wedge laser tuner

    NASA Technical Reports Server (NTRS)

    1984-01-01

    A fringe detection and measurement system was constructed for use with the CNRS Fizeau wedge laser tuner, consisting of three circuit boards. The first board is a standard Reticon RC-100 B motherboard which is used to provide the timing, video processing, and housekeeping functions required by the Reticon RL-512 G photodiode array used in the system. The sampled and held video signal from the motherboard is processed by a second, custom fabricated circuit board which contains a high speed fringe detection and locating circuit. This board includes a dc level discriminator type fringe detector, a counter circuit to determine fringe center, a pulsed laser triggering circuit, and a control circuit to operate the shutter for the He-Ne reference laser beam. The fringe center information is supplied to the third board, a commercial single board computer, which governs the data collection process and interprets the results.

  15. A Study of Certificated Salaries and Fringe Benefits of California Community College Districts, 1990-91.

    ERIC Educational Resources Information Center

    Kern Community Coll. District, Bakersfield, CA.

    In January 1991, a study was conducted to assess the fringe benefit programs of community college districts in California, and to determine the total dollar amounts paid to certified employees. Questionnaires requesting fringe benefits and salary information for 1990-91 were mailed to all 71 districts in the state. Rankings of salaries at three…

  16. 26 CFR 1.132-6T - De minimis fringe-1985 through 1988 (temporary).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 2 2010-04-01 2010-04-01 false De minimis fringe-1985 through 1988 (temporary....132-6T De minimis fringe—1985 through 1988 (temporary). (a) In general. Gross income does not include the value of a de minimis fringe provided to an employee. The term “de minimis fringe” means any...

  17. 26 CFR 1.132-6T - De minimis fringe-1985 through 1988 (temporary).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 2 2011-04-01 2011-04-01 false De minimis fringe-1985 through 1988 (temporary....132-6T De minimis fringe—1985 through 1988 (temporary). (a) In general. Gross income does not include the value of a de minimis fringe provided to an employee. The term “de minimis fringe” means any...

  18. Fringe Benefits for Administrators in Public Schools, 1979-80. Part 2 of National Survey of Fringe Benefits in Public Schools. ERS Report.

    ERIC Educational Resources Information Center

    Educational Research Service, Arlington, VA.

    Thirty tables present data from the third biennial survey of fringe benefits among non-superintendent administrators and supervisors in public elementary and secondary school systems. Designed to help school boards and administrators assess their non-cash compensation packages, the national survey drew responses from 803 districts in a random…

  19. Information retrieval from holographic interferograms: Fundamentals and problems

    NASA Technical Reports Server (NTRS)

    Vest, Charles M.

    1987-01-01

    Holographic interferograms can contain large amounts of information about flow and temperature fields. Their information content can be very high because they can be viewed from many different directions. This multidirectionality, and fringe localization add to the information contained in the fringe pattern if diffuse illumination is used. Additional information, and increased accuracy can be obtained through the use of dual reference wave holography to add reference fringes or to effect discrete phase shift or hetrodyne interferometry. Automated analysis of fringes is possible if interferograms are of simple structure and good quality. However, in practice a large number of practical problems can arise, so that a difficult image processing task results.

  20. Application of digital interferogram evaluation techniques to the measurement of 3-D flow fields

    NASA Technical Reports Server (NTRS)

    Becker, Friedhelm; Yu, Yung H.

    1987-01-01

    A system for digitally evaluating interferograms, based on an image processing system connected to a host computer, was implemented. The system supports one- and two-dimensional interferogram evaluations. Interferograms are digitized, enhanced, and then segmented. The fringe coordinates are extracted, and the fringes are represented as polygonal data structures. Fringe numbering and fringe interpolation modules are implemented. The system supports editing and interactive features, as well as graphic visualization. An application of the system to the evaluation of double exposure interferograms from the transonic flow field around a helicopter blade and the reconstruction of the three dimensional flow field is given.

  1. Self-organization of a periodic structure between amorphous and crystalline phases in a GeTe thin film induced by femtosecond laser pulse amorphization

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

    Katsumata, Y.; Morita, T.; Morimoto, Y.

    A self-organized fringe pattern in a single amorphous mark of a GeTe thin film was formed by multiple femtosecond pulse amorphization. Micro Raman measurement indicates that the fringe is a periodic alternation between crystalline and amorphous phases. The period of the fringe is smaller than the irradiation wavelength and the direction is parallel to the polarization direction. Snapshot observation revealed that the fringe pattern manifests itself via a complex but coherent process, which is attributed to crystallization properties unique to a nonthermally amorphized phase and the distinct optical contrast between crystalline and amorphous phases.

  2. A generalization of the theory of fringe patterns containing displacement information

    NASA Astrophysics Data System (ADS)

    Sciammarella, C. A.; Bhat, G.

    The theory that provides the interpretation of interferometric fringes as frequency modulated signals, is used to show that the electrooptical system used to analyze fringe patterns can be considered as a simultaneous Fourier spectrum analyzer. This interpretation generalizes the quasi-heterodyning techniques. It is pointed out that the same equations that yield the discrete Fourier transform as summations, yield correct values for a reduced number of steps. Examples of application of the proposed technique to electronic holography are given. It is found that for a uniform field the standard deviation of the individual readings is 1/20 of the fringe spacing.

  3. Boundary-layer transition and global skin friction measurement with an oil-fringe imaging technique

    NASA Technical Reports Server (NTRS)

    Monson, Daryl J.; Mateer, George G.; Menter, Florian R.

    1993-01-01

    A new oil-fringe imaging system skin friction (FISF) technique to measure skin friction on wind tunnel models is presented. In the method used to demonstrate the technique, lines of oil are applied on surfaces that connect the intended sets of measurement points, and then a wind tunnel is run so that the oil thins and forms interference fringes that are spaced in proportion to local skin friction. After a run the fringe spacings are imaged with a CCD-array digital camera and measured on a computer. Skin friction and transition measurements on a two-dimensional wing are presented and compared with computational predictions.

  4. Eliminating the zero spectrum in Fourier transform profilometry using empirical mode decomposition.

    PubMed

    Li, Sikun; Su, Xianyu; Chen, Wenjing; Xiang, Liqun

    2009-05-01

    Empirical mode decomposition is introduced into Fourier transform profilometry to extract the zero spectrum included in the deformed fringe pattern without the need for capturing two fringe patterns with pi phase difference. The fringe pattern is subsequently demodulated using a standard Fourier transform profilometry algorithm. With this method, the deformed fringe pattern is adaptively decomposed into a finite number of intrinsic mode functions that vary from high frequency to low frequency by means of an algorithm referred to as a sifting process. Then the zero spectrum is separated from the high-frequency components effectively. Experiments validate the feasibility of this method.

  5. Highlight removal based on the regional-projection fringe projection method

    NASA Astrophysics Data System (ADS)

    Qi, Zhaoshuai; Wang, Zhao; Huang, Junhui; Xing, Chao; Gao, Jianmin

    2018-04-01

    In fringe projection profilometry, highlight usually causes the saturation and blooming in captured fringes and reduces the measurement accuracy. To solve the problem, a regional-projection fringe projection (RP-FP) method is proposed. Regional projection patterns (RP patterns) are projected onto the tested object surface to avoid the saturation and blooming. Then, an image inpainting technique is employed to reconstruct the missing phases in the captured RP patterns and a complete surface of the tested object is obtained. Experiments verified the effectiveness of the proposed method. The method can be widely used in industrial inspections and quality controlling in mechanical and manufacturing industries.

  6. Diffraction of a Gaussian laser beam by a straight edge leading to the formation of optical vortices and elliptical diffraction fringes

    NASA Astrophysics Data System (ADS)

    Zeylikovich, Iosif; Nikitin, Aleksandr

    2018-04-01

    The diffraction of a Gaussian laser beam by a straight edge has been studied theoretically and experimentally for many years. In this paper, we have experimentally observed for the first time the formation of the cusped caustic (for the Fresnel number F ≈ 100) in the shadow region of the straight edge, with the cusp placed near the center of the circular laser beam(λ = 0 . 65 μm) overlapped with the elliptical diffraction fringes. These fringes are originated at the region near the cusp of the caustic where light intensity is zero and the wave phase is singular (the optical vortex). We interpret observed diffraction fringes as a result of interference between the helical wave created by the optical vortex and cylindrical wave diffracted at the straight edge. We have theoretically revealed that the number of high contrast diffraction fringes observable in a shadow region is determined by the square of the diffracted angles in the range of spatial frequencies of the scattered light field in excellent agreement with experiments. The extra phase singularities with opposite charges are also observed along the shadow boundary as the fork-like diffraction fringes.

  7. Combination of oriented partial differential equation and shearlet transform for denoising in electronic speckle pattern interferometry fringe patterns.

    PubMed

    Xu, Wenjun; Tang, Chen; Gu, Fan; Cheng, Jiajia

    2017-04-01

    It is a key step to remove the massive speckle noise in electronic speckle pattern interferometry (ESPI) fringe patterns. In the spatial-domain filtering methods, oriented partial differential equations have been demonstrated to be a powerful tool. In the transform-domain filtering methods, the shearlet transform is a state-of-the-art method. In this paper, we propose a filtering method for ESPI fringe patterns denoising, which is a combination of second-order oriented partial differential equation (SOOPDE) and the shearlet transform, named SOOPDE-Shearlet. Here, the shearlet transform is introduced into the ESPI fringe patterns denoising for the first time. This combination takes advantage of the fact that the spatial-domain filtering method SOOPDE and the transform-domain filtering method shearlet transform benefit from each other. We test the proposed SOOPDE-Shearlet on five experimentally obtained ESPI fringe patterns with poor quality and compare our method with SOOPDE, shearlet transform, windowed Fourier filtering (WFF), and coherence-enhancing diffusion (CEDPDE). Among them, WFF and CEDPDE are the state-of-the-art methods for ESPI fringe patterns denoising in transform domain and spatial domain, respectively. The experimental results have demonstrated the good performance of the proposed SOOPDE-Shearlet.

  8. Effect of fringe-artifact correction on sub-tomogram averaging from Zernike phase-plate cryo-TEM

    PubMed Central

    Kishchenko, Gregory P.; Danev, Radostin; Fisher, Rebecca; He, Jie; Hsieh, Chyongere; Marko, Michael; Sui, Haixin

    2015-01-01

    Zernike phase-plate (ZPP) imaging greatly increases contrast in cryo-electron microscopy, however fringe artifacts appear in the images. A computational de-fringing method has been proposed, but it has not been widely employed, perhaps because the importance of de-fringing has not been clearly demonstrated. For testing purposes, we employed Zernike phase-plate imaging in a cryo-electron tomographic study of radial-spoke complexes attached to microtubule doublets. We found that the contrast enhancement by ZPP imaging made nonlinear denoising insensitive to the filtering parameters, such that simple low-frequency band-pass filtering made the same improvement in map quality. We employed sub-tomogram averaging, which compensates for the effect of the “missing wedge” and considerably improves map quality. We found that fringes (caused by the abrupt cut-on of the central hole in the phase plate) can lead to incorrect representation of a structure that is well-known from the literature. The expected structure was restored by amplitude scaling, as proposed in the literature. Our results show that de-fringing is an important part of image-processing for cryo-electron tomography of macromolecular complexes with ZPP imaging. PMID:26210582

  9. Suppression of contrast-related artefacts in phase-measuring structured light techniques

    NASA Astrophysics Data System (ADS)

    Burke, Jan; Zhong, Liang

    2017-06-01

    Optical metrology using phase measurements has benefited significantly from the introduction of phase-shifting methods, first in interferometry, then also in fringe projection and fringe reflection. As opposed to interferometry, the latter two techniques generally use a spatiotemporal phase-shifting approach: A sequence of fringe patterns with varying spacing is used, and a phase map of each is generated by temporal phase shifting, to allow unique assignments of projector or screen pixels to camera pixels. One ubiquitous problem with phase-shifting structured-light techniques is that phase artefacts appear near regions of the image where the modulation amplitude of the projected or reflected fringes changes abruptly, e.g. near dirt/dust particles on the surface in deflectometry or bright-dark object colour transitions in fringe projection. Near the bright-dark boundaries, responses in the phase maps appear that are not plausible as actual surface features. The phenomenon has been known for a long time but is usually ignored because it does not compromise the overall reliability of results. In deflectometry, however, often the objective is to find and classify small defects, and of course it is then important to distinguish between bogus phase responses caused by fringe modulation changes, and actual surface defects. We present, for what we believe is the first time, an analytical derivation of the error terms, study the parameters influencing the phase artefacts (in particular the fringe period), and suggest some simple algorithms to minimise them.

  10. 49 CFR 1242.29 - Fringe benefits (accounts 12-17-00, 12-18-00, and 12-19-00).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Fringe benefits (accounts 12-17-00, 12-18-00, and... RAILROADS 1 Operating Expenses-Way and Structures § 1242.29 Fringe benefits (accounts 12-17-00, 12-18-00, and 12-19-00). Separate common expenses in the running subactivity in the same proportion as the...

  11. Fringe Benefits for Superintendents in Public Schools, 1979-80. Part 1 of National Survey of Fringe Benefits in Public Schools. ERS Report.

    ERIC Educational Resources Information Center

    Educational Research Service, Arlington, VA.

    Displayed in 38 tables, the data in this third biennial survey of public school superintendents' fringe benefits are designed to help school boards and administrators assess their non-cash compensation packages. A national sample of 797 school districts--stratified by district enrollment size, expenditure per pupil, and geographic region--supplied…

  12. Three-dimensional displacement measurement by fringe projection and speckle photography

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

    Barrientos, B.; Garcia-Marquez, J.; Cerca, M.

    2008-04-15

    3D displacement fields are measured by the combination of two optical methods, fringe projection and speckle photography. The use of only one camera recording the necessary information implies that no calibration procedures are necessary as is the case in techniques based on stereoscopy. The out-of-plane displacement is measured by fringe projection whereas speckle photography yields the 2-D in-plane component. To show the feasibility of the technique, we analyze a detailed morphological spatio-temporal evolution of a model of the Earth's crust while subjected to compression forces. The results show that the combination of fringe projection and speckle photography is well suitedmore » for this type of studies.« less

  13. Diffraction in volume reflection gratings with variable fringe contrast.

    PubMed

    Brotherton-Ratcliffe, David; Bjelkhagen, Hans; Osanlou, Ardeshir; Excell, Peter

    2015-06-01

    The PSM model is used to analyze the process of diffraction occurring in volume reflection gratings in which fringe contrast is an arbitrary function of distance within the grating. General analytic expressions for diffraction efficiency at Bragg resonance are obtained for unslanted panchromatic lossless reflection gratings at oblique incidence. These formulas are then checked for several diverse fringe contrast profiles with numerical solutions of the Helmholtz equation, where exceptionally good agreement is observed. Away from Bragg resonance, the case of the hyperbolically decaying fringe contrast profile is shown to lead to an analytic expression for the diffraction efficiency and this is again compared successfully with numerical solutions of the Helmholtz equation.

  14. Remedial Amendment Delivery near the Water Table Using Shear Thinning Fluids: Experiments and Numerical Simulations

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

    Oostrom, Martinus; Truex, Michael J.; Vermeul, Vincent R.

    2014-08-19

    The use of shear thinning fluids (STFs) containing xanthan is a potential enhancement for emplacing a solute amendment near the water table and within the capillary fringe. Most research to date related to STF behavior has involved saturated and confined conditions. A series of flow cell experiments were conducted to investigate STF emplacement in variable saturated homogeneous and layered heterogeneous systems. Besides flow visualization using dyes, amendment concentrations and pressure data were obtained at several locations. The experiments showed that injection of STFs considerably improved the subsurface distribution near the water table by mitigating preferential flow through higher permeability zonesmore » compared to no-polymer injections. The phosphate amendment migrated with the xanthan SFT without retardation. Despite the high viscosity of the STF, no excessive mounding or preferential flow were observed in the unsaturated zone. The STOMP simulator was able to predict the experimentally observed fluid displacement and amendment concentrations reasonably well. Cross flow between layers could be interpreted as the main mechanism to transport STFs into lower permeability layers based on the observed pressure gradient and concentration data in layers of differing hydraulic conductivity.« less

  15. Laboratory meter-scale seismic monitoring of varying water levels in granular media

    NASA Astrophysics Data System (ADS)

    Pasquet, S.; Bodet, L.; Bergamo, P.; Guérin, R.; Martin, R.; Mourgues, R.; Tournat, V.

    2016-12-01

    Laboratory physical modelling and non-contacting ultrasonic techniques are frequently proposed to tackle theoretical and methodological issues related to geophysical prospecting. Following recent developments illustrating the ability of seismic methods to image spatial and/or temporal variations of water content in the vadose zone, we developed laboratory experiments aimed at testing the sensitivity of seismic measurements (i.e., pressure-wave travel times and surface-wave phase velocities) to water saturation variations. Ultrasonic techniques were used to simulate typical seismic acquisitions on small-scale controlled granular media presenting different water levels. Travel times and phase velocity measurements obtained at the dry state were validated with both theoretical models and numerical simulations and serve as reference datasets. The increasing water level clearly affects the recorded wave field in both its phase and amplitude, but the collected data cannot yet be inverted in the absence of a comprehensive theoretical model for such partially saturated and unconsolidated granular media. The differences in travel time and phase velocity observed between the dry and wet models show patterns that are interestingly coincident with the observed water level and depth of the capillary fringe, thus offering attractive perspectives for studying soil water content variations in the field.

  16. Semianalytical model predicting transfer of volatile pollutants from groundwater to the soil surface.

    PubMed

    Atteia, Olivier; Höhener, Patrick

    2010-08-15

    Volatilization of toxic organic contaminants from groundwater to the soil surface is often considered an important pathway in risk analysis. Most of the risk models use simplified linear solutions that may overpredict the volatile flux. Although complex numerical models have been developed, their use is restricted to experienced users and for sites where field data are known in great detail. We present here a novel semianalytical model running on a spreadsheet that simulates the volatilization flux and vertical concentration profile in a soil based on the Van Genuchten functions. These widely used functions describe precisely the gas and water saturations and movement in the capillary fringe. The analytical model shows a good accuracy over several orders of magnitude when compared to a numerical model and laboratory data. The effect of barometric pumping is also included in the semianalytical formulation, although the model predicts that barometric pumping is often negligible. A sensitivity study predicts significant fluxes in sandy vadose zones and much smaller fluxes in other soils. Fluxes are linked to the dimensionless Henry's law constant H for H < 0.2 and increase by approximately 20% when temperature increases from 5 to 25 degrees C.

  17. Microbial communities along biogeochemical gradients in a hydrocarbon-contaminated aquifer.

    PubMed

    Tischer, Karolin; Kleinsteuber, Sabine; Schleinitz, Kathleen M; Fetzer, Ingo; Spott, Oliver; Stange, Florian; Lohse, Ute; Franz, Janett; Neumann, Franziska; Gerling, Sarah; Schmidt, Christian; Hasselwander, Eyk; Harms, Hauke; Wendeberg, Annelie

    2013-09-01

    Micro-organisms are known to degrade a wide range of toxic substances. How the environment shapes microbial communities in polluted ecosystems and thus influences degradation capabilities is not yet fully understood. In this study, we investigated microbial communities in a highly complex environment: the capillary fringe and subjacent sediments in a hydrocarbon-contaminated aquifer. Sixty sediment sections were analysed using terminal restriction fragment length polymorphism (T-RFLP) fingerprinting, cloning and sequencing of bacterial and archaeal 16S rRNA genes, complemented by chemical analyses of petroleum hydrocarbons, methane, oxygen and alternative terminal electron acceptors. Multivariate statistics revealed concentrations of contaminants and the position of the water table as significant factors shaping the microbial community composition. Micro-organisms with highest T-RFLP abundances were related to sulphate reducers belonging to the genus Desulfosporosinus, fermenting bacteria of the genera Sedimentibacter and Smithella, and aerobic hydrocarbon degraders of the genus Acidovorax. Furthermore, the acetoclastic methanogens Methanosaeta, and hydrogenotrophic methanogens Methanocella and Methanoregula were detected. Whereas sulphate and sulphate reducers prevail at the contamination source, the detection of methane, fermenting bacteria and methanogenic archaea further downstream points towards syntrophic hydrocarbon degradation. © 2013 John Wiley & Sons Ltd and Society for Applied Microbiology.

  18. Looking Under a Leidenfrost Drop

    NASA Astrophysics Data System (ADS)

    Burton, Justin; Sharpe, Aaron; van der Veen, Roeland; Franco, Andres; Nagel, Sidney

    2011-11-01

    The Leidenfrost effect can be observed when small water drops move around effortlessly without sticking on a hot pan. The transition to a levitated state, where the drops rest on an insulating layer of vapor, occurs at the Leidenfrost temperature. Experiment and theory have examined the lifetime and maximum size of Leidenfrost drops. However, the liquid-vapor interface beneath the drop has not been fully charcterized. We report experiments using laser-light interference to measure the geometry of the liquid-vapor interface. By imaging the interference fringes produced between the bottom surface of the liquid and the hot substrate, we can measure the curvature of the vapor pocket beneath the drop as well as the azimuthal undulations along the neck that sits closest to the surface. From these measurements, we can extrapolate the shape of the bottom of the drop, which fluctuates in time with a period of a few milliseconds for millimeter-sized water drops. Our measurements of the azimuthal neck radius agree with predictions: the difference between the drop and neck radii, (Rd -Rn) ~0.53 λ in the limit of large drops where λ is the capillary length of the fluid. For small drops we recover the result found in that Rn ~Rd2 / λ .

  19. Phase retrieval in digital speckle pattern interferometry by application of two-dimensional active contours called snakes.

    PubMed

    Federico, Alejandro; Kaufmann, Guillermo H

    2006-03-20

    We propose a novel approach to retrieving the phase map coded by a single closed-fringe pattern in digital speckle pattern interferometry, which is based on the estimation of the local sign of the quadrature component. We obtain the estimate by calculating the local orientation of the fringes that have previously been denoised by a weighted smoothing spline method. We carry out the procedure of sign estimation by determining the local abrupt jumps of size pi in the orientation field of the fringes and by segmenting the regions defined by these jumps. The segmentation method is based on the application of two-dimensional active contours (snakes), with which one can also estimate absent jumps, i.e., those that cannot be detected from the local orientation of the fringes. The performance of the proposed phase-retrieval technique is evaluated for synthetic and experimental fringes and compared with the results obtained with the spiral-phase- and Fourier-transform methods.

  20. From Payday Loans To Pawnshops: Fringe Banking, The Unbanked, And Health.

    PubMed

    Eisenberg-Guyot, Jerzy; Firth, Caislin; Klawitter, Marieka; Hajat, Anjum

    2018-03-01

    The fringe banking industry, including payday lenders and check cashers, was nearly nonexistent three decades ago. Today it generates tens of billions of dollars in annual revenue. The industry's growth accelerated in the 1980s with financial deregulation and the working class's declining resources. With Current Population Survey data, we used propensity score matching to investigate the relationship between fringe loan use, unbanked status, and self-rated health, hypothesizing that the material and stress effects of exposure to these financial services would be harmful to health. We found that fringe loan use was associated with 38 percent higher prevalence of poor or fair health, while being unbanked (not having one's own bank account) was associated with 17 percent higher prevalence. Although a variety of policies could mitigate the health consequences of these exposures, expanding social welfare programs and labor protections would address the root causes of the use of fringe services and advance health equity.

  1. The Least-Squares Calibration on the Micro-Arcsecond Metrology Test Bed

    NASA Technical Reports Server (NTRS)

    Zhai, Chengxing; Milman, Mark H.; Regehr, Martin W.

    2006-01-01

    The Space Interferometry Mission (S1M) will measure optical path differences (OPDs) with an accuracy of tens of picometers, requiring precise calibration of the instrument. In this article, we present a calibration approach based on fitting star light interference fringes in the interferometer using a least-squares algorithm. The algorithm is first analyzed for the case of a monochromatic light source with a monochromatic fringe model. Using fringe data measured on the Micro-Arcsecond Metrology (MAM) testbed with a laser source, the error in the determination of the wavelength is shown to be less than 10pm. By using a quasi-monochromatic fringe model, the algorithm can be extended to the case of a white light source with a narrow detection bandwidth. In SIM, because of the finite bandwidth of each CCD pixel, the effect of the fringe envelope can not be neglected, especially for the larger optical path difference range favored for the wavelength calibration.

  2. Holographic interferometry of transparent media using light scattered by embedded test objects

    NASA Technical Reports Server (NTRS)

    Prikryl, I.; Vest, C. M.

    1982-01-01

    Fringe formation and localization in holographic interferometry of transparent media are discussed for configurations in which light enters the medium and is scattered back through it by an embedded diffuse object. Fringe order numbers are doubled, and the fringe localization region is translated and compressed by a factor of two. The results are applicable to tomographic reconstruction of aerodynamic density fields around opaque test objects.

  3. Adaptive pixel-to-pixel projection intensity adjustment for measuring a shiny surface using orthogonal color fringe pattern projection

    NASA Astrophysics Data System (ADS)

    Chen, Chao; Gao, Nan; Wang, Xiangjun; Zhang, Zonghua

    2018-05-01

    Three-dimensional (3D) shape measurement based on fringe pattern projection techniques has been commonly used in various fields. One of the remaining challenges in fringe pattern projection is that camera sensor saturation may occur if there is a large range of reflectivity variation across the surface that causes measurement errors. To overcome this problem, a novel fringe pattern projection method is proposed to avoid image saturation and maintain high-intensity modulation for measuring shiny surfaces by adaptively adjusting the pixel-to-pixel projection intensity according to the surface reflectivity. First, three sets of orthogonal color fringe patterns and a sequence of uniform gray-level patterns with different gray levels are projected onto a measured surface by a projector. The patterns are deformed with respect to the object surface and captured by a camera from a different viewpoint. Subsequently, the optimal projection intensity at each pixel is determined by fusing different gray levels and transforming the camera pixel coordinate system into the projector pixel coordinate system. Finally, the adapted fringe patterns are created and used for 3D shape measurement. Experimental results on a flat checkerboard and shiny objects demonstrate that the proposed method can measure shiny surfaces with high accuracy.

  4. Characterization of depolarizing fringing fields of a liquid crystal spatial light modulator for laser beam steering

    NASA Astrophysics Data System (ADS)

    Haellstig, Emil J.; Martin, Torleif; Stigwall, Johan; Sjoqvist, Lars; Lindgren, Mikael

    2004-02-01

    A commercial linear one-dimensional, 1x4096 pixels, zero-twist nematic liquid crystal spatial light modulator (SLM), giving more than 2π phase modulation at λ = 850 nm, was evaluated for beam steering applications. The large ratio (7:1) between the liquid crystal layer thickness and pixel width gives rise to voltage leakage and fringing fields between pixels. Due to the fringing fields the ideal calculated phase patterns cannot be perfectly realized by the device. Losses in high frequency components in the phase patterns were found to limit the maximum deflection angle. The inhomogeneous optical anisotropy of the SLM was determined by modelling of the liquid crystal director distribution within the electrode-pixel structure. The effects of the fringing fields on the amplitude and phase modulation were studied by full vector finite-difference time-domain simulations. It was found that the fringing fields also resulted in coupling into an unwanted polarization mode. Measurements of how this mode coupling affects the beam steering quality were carried out and the results compared with calculated results. A method to compensate for the fringing field effects is discussed and it is shown how the usable steering range of the SLM can be extended to +/- 2 degrees.

  5. The Apical Actin Fringe Contributes to Localized Cell Wall Deposition and Polarized Growth in the Lily Pollen Tube1[W][OPEN

    PubMed Central

    Rounds, Caleb M.; Hepler, Peter K.; Winship, Lawrence J.

    2014-01-01

    In lily (Lilium formosanum) pollen tubes, pectin, a major component of the cell wall, is delivered through regulated exocytosis. The targeted transport and secretion of the pectin-containing vesicles may be controlled by the cortical actin fringe at the pollen tube apex. Here, we address the role of the actin fringe using three different inhibitors of growth: brefeldin A, latrunculin B, and potassium cyanide. Brefeldin A blocks membrane trafficking and inhibits exocytosis in pollen tubes; it also leads to the degradation of the actin fringe and the formation of an aggregate of filamentous actin at the base of the clear zone. Latrunculin B, which depolymerizes filamentous actin, markedly slows growth but allows focused pectin deposition to continue. Of note, the locus of deposition shifts frequently and correlates with changes in the direction of growth. Finally, potassium cyanide, an electron transport chain inhibitor, briefly stops growth while causing the actin fringe to completely disappear. Pectin deposition continues but lacks focus, instead being delivered in a wide arc across the pollen tube tip. These data support a model in which the actin fringe contributes to the focused secretion of pectin to the apical cell wall and, thus, to the polarized growth of the pollen tube. PMID:25037212

  6. The Mass1frings mutation underlies early onset hearing impairment in BUB/BnJ mice, a model for the auditory pathology of Usher syndrome IIC

    PubMed Central

    Johnson, K.R.; Zheng, Q.Y.; Weston, M.D.; Ptacek, L.J.; Noben-Trauth, K.

    2010-01-01

    The human ortholog of the gene responsible for audiogenic seizure susceptibility in Frings and BUB/BnJ mice (mouse gene symbol Mass1) recently was shown to underlie Usher syndrome type IIC (USH2C). Here we report that the Mass1frings mutation is responsible for the early onset hearing impairment of BUB/BnJ mice. We found highly significant linkage of Mass1 with ABR threshold variation among mice from two backcrosses involving BUB/BnJ mice with mice of strains CAST/EiJ and MOLD/RkJ. We also show an additive effect of the Cdh23 locus in modulating the progression of hearing loss in backcross mice. Together, these two loci account for more than 70% of the total ABR threshold variation among the backcross mice at all ages. The modifying effect of the strain-specific Cdh23ahl variant may account for the hearing and audiogenic seizure differences observed between Frings and BUB/BnJ mice, which share the Mass1frings mutation. During postnatal cochlear development in BUB/BnJ mice, stereocilia bundles develop abnormally and remain immature and splayed into adulthood, corresponding with the early onset hearing impairment associated with Mass1frings. Progressive base–apex hair cell degeneration occurs at older ages, corresponding with the age-related hearing loss associated with Cdh23ahl. The molecular basis and pathophysiology of hearing loss suggest BUB/BnJ and Frings mice as models to study cellular and molecular mechanisms underlying USH2C auditory pathology. PMID:15820310

  7. Carrier and aberrations removal in interferometric fringe projection profilometry

    NASA Astrophysics Data System (ADS)

    Blain, P.; Michel, F.; Renotte, Y.; Habraken, S.

    2012-04-01

    A profilometer which takes advantage of polarization states splitting technique and monochromatic light projection method as a way to overcome ambient lighting for in-situ measurement is under development [1, 2]. Because of the Savart plate which refracts two out of axis beams, the device suffers from aberrations (mostly coma and astigmatism). These aberrations affect the quality of the sinusoidal fringe pattern. In fringe projection profilometry, the unwrapped phase distribution map contains the sum of the object's shape-related phase and carrier-fringe-related phase. In order to extract the 3D shape of the object, the carrier phase has to be removed [3, 4]. An easy way to remove both the fringe carrier and the aberrations of the optical system is to measure the phases of the test object and to measure the phase of a reference plane with the same set up and to subtract both phase maps. This time consuming technique is suitable for laboratory but not for industry. We propose a method to numerically remove both the fringe carrier and the aberrations. A first reference phase of a calibration plane is evaluated knowing the position of the different elements in the set up and the orientation of the fringes. Then a fitting of the phase map by Zernike polynomials is computed [5]. As the triangulation parameters are known during the calibration, the computation of Zernike coefficients has only to be made once. The wavefront error can be adjusted by a scale factor which depends on the position of the test object.

  8. FFT swept filtering: a bias-free method for processing fringe signals in absolute gravimeters

    NASA Astrophysics Data System (ADS)

    Křen, Petr; Pálinkáš, Vojtech; Mašika, Pavel; Val'ko, Miloš

    2018-05-01

    Absolute gravimeters, based on laser interferometry, are widely used for many applications in geoscience and metrology. Although currently the most accurate FG5 and FG5X gravimeters declare standard uncertainties at the level of 2-3 μGal, their inherent systematic errors affect the gravity reference determined by international key comparisons based predominately on the use of FG5-type instruments. The measurement results for FG5-215 and FG5X-251 clearly showed that the measured g-values depend on the size of the fringe signal and that this effect might be approximated by a linear regression with a slope of up to 0.030 μGal/mV . However, these empirical results do not enable one to identify the source of the effect or to determine a reasonable reference fringe level for correcting g-values in an absolute sense. Therefore, both gravimeters were equipped with new measuring systems (according to Křen et al. in Metrologia 53:27-40, 2016. https://doi.org/10.1088/0026-1394/53/1/27 applied for FG5), running in parallel with the original systems. The new systems use an analogue-to-digital converter HS5 to digitize the fringe signal and a new method of fringe signal analysis based on FFT swept bandpass filtering. We demonstrate that the source of the fringe size effect is connected to a distortion of the fringe signal due to the electronic components used in the FG5(X) gravimeters. To obtain a bias-free g-value, the FFT swept method should be applied for the determination of zero-crossings. A comparison of g-values obtained from the new and the original systems clearly shows that the original system might be biased by approximately 3-5 μGal due to improperly distorted fringe signal processing.

  9. Computer aided fringe pattern analysis

    NASA Astrophysics Data System (ADS)

    Sciammarella, Cesar A.

    The paper reviews the basic laws of fringe pattern interpretation. The different techniques that are currently utilized are presented using a common frame of reference stressing the fact that these techniques are different variations of the same basic principle. Digital and analog techniques are discussed. Currently available hardware is presented and the relationships between hardware and the operations of pattern fringe processing are pointed out. Examples are given to illustrate the ideas discussed in the paper.

  10. Two dimensional Fourier transform methods for fringe pattern analysis

    NASA Astrophysics Data System (ADS)

    Sciammarella, C. A.; Bhat, G.

    An overview of the use of FFTs for fringe pattern analysis is presented, with emphasis on fringe patterns containing displacement information. The techniques are illustrated via analysis of the displacement and strain distributions in the direction perpendicular to the loading, in a disk under diametral compression. The experimental strain distribution is compared to the theoretical, and the agreement is found to be excellent in regions where the elasticity solution models well the actual problem.

  11. Analysis of contact zones from whole field isochromatics using reflection photoelasticity

    NASA Astrophysics Data System (ADS)

    Hariprasad, M. P.; Ramesh, K.

    2018-06-01

    This paper discusses the method for evaluating the unknown contact parameters by post processing the whole field fringe order data obtained from reflection photoelasticity in a nonlinear least squares sense. Recent developments in Twelve Fringe Photoelasticity (TFP) for fringe order evaluation from single isochromatics is utilized for the whole field fringe order evaluation. One of the issues in using TFP for reflection photoelasticity is the smudging of isochromatic data at the contact zone. This leads to error in identifying the origin of contact, which is successfully addressed by implementing a semi-automatic contact point refinement algorithm. The methodologies are initially verified for benchmark problems and demonstrated for two application problems of turbine blade and sheet pile contacting interfaces.

  12. Modeling of Dipole and Quadrupole Fringe-Field Effects for the Advanced Photon Source Upgrade Lattice

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

    Borland, M.; Lindberg, R.

    2017-06-01

    The proposed upgrade of the Advanced Photon Source (APS) to a multibend-achromat lattice requires shorter and much stronger quadrupole magnets than are present in the existing ring. This results in longitudinal gradient profiles that differ significantly from a hard-edge model. Additionally, the lattice assumes the use of five-segment longitudinal gradient dipoles. Under these circumstances, the effects of fringe fields and detailed field distributions are of interest. We evaluated the effect of soft-edge fringe fields on the linear optics and chromaticity, finding that compensation for these effects is readily accomplished. In addition, we evaluated the reliability of standard methods of simulatingmore » hardedge nonlinear fringe effects in quadrupoles.« less

  13. Strain distribution in an Si single crystal measured by interference fringes of X-ray mirage diffraction

    PubMed Central

    Jongsukswat, Sukswat; Fukamachi, Tomoe; Ju, Dongying; Negishi, Riichirou; Hirano, Keiichi; Kawamura, Takaaki

    2013-01-01

    In X-ray interference fringes accompanied by mirage diffraction, variations have been observed in the spacing and position of the fringes from a plane-parallel Si single crystal fixed at one end as a function of distance from the incident plane of the X-rays to the free crystal end. The variations can be explained by distortion of the sample crystal due to gravity. From the variations and positions of the fringes, the strain gradient of the crystal has been determined. The distribution of the observed strain agrees with that expected from rod theory except for residual strain. When the distortion is large, the observed strain distribution does not agree with that expected from rod theory. PMID:24068841

  14. Atmospheric tomography using a fringe pattern in the sodium layer.

    PubMed

    Baharav, Y; Ribak, E N; Shamir, J

    1994-02-15

    We wish to measure and separate the contribution of atmospheric turbulent layers for multiconjugate adaptive optics. To this end, we propose to create a periodic fringe pattern in the sodium layer and image it with a modified Hartmann sensor. Overlapping sections of the fringes are imaged by a lenslet array onto contiguous areas in a large-format camera. Low-layer turbulence causes an overall shift of the fringe pattern in each lenslet, and high-attitude turbulence results in internal deformations in the pattern. Parallel Fourier analysis permits separation of the atmospheric layers. Two mirrors, one conjugate to a ground layer and the other conjugate to a single high-altitude layer, are shown to widen the field of view significantly compared with existing methods.

  15. Anacostia River fringe wetlands restoration project: final report for the five-year monitoring program (2003 through 2007)

    USGS Publications Warehouse

    Krafft, Cairn C.; Hammerschlag, Richard S.; Guntenspergen, Glenn R.

    2009-01-01

    The 6-hectare (ha) freshwater tidal Anacostia River Fringe Wetlands (Fringe Wetlands) were reconstructed along the mainstem of the Anacostia River in Washington, DC (Photograph 1, Figure 1) during the summer of 2003. The Fringe Wetlands consist of two separate planting cells. Fringe A, located adjacent to Lower Kingman Island, on the west bank of the Anacostia River, occupies 1.6 ha; Fringe B, located on the east bank of the Anacostia River, occupies 4.4 ha. This project is the third in a series of freshwater tidal wetland reconstructions on the Anacostia River designed and implemented by the US Army Corps of Engineers (USACE) Baltimore District and District Department of the Environment (DDOE) on lands managed by the National Park Service (NPS). The first was Kenilworth Marsh, reconstructed in 1993 (Syphax and Hammerschlag 2005); the second was Kingman Marsh, reconstructed in 2000 (Hammerschlag et al. 2006). Kenilworth and Kingman were both constructed in low-energy backwaters of the Anacostia. However, the Fringe Wetlands, which were constructed on two pre-existing benches along the high-energy mainstem, required sheet piling to provide protection from erosive impacts of increased flow and volume of water associated with storm events during the establishment phase (Photograph 2). All three projects required the placement of dredged sediment materials to increase elevations enough to support emergent vegetation (Photograph 3). The purpose of all three wetland reconstruction projects was to restore pieces of the once extensive tidal freshwater marsh habitat that bordered the Anacostia River historically, prior to the dredge and fill operations and sea wall installation that took place there in the early to mid-1900's (Photograph 4).

  16. Laser angle sensor

    NASA Technical Reports Server (NTRS)

    Pond, C. R.; Texeira, P. D.

    1985-01-01

    A laser angle measurement system was designed and fabricated for NASA Langley Research Center. The instrument is a fringe counting interferometer that monitors the pitch attitude of a model in a wind tunnel. A laser source and detector are mounted above the model. Interference fringes are generated by a small passive element on the model. The fringe count is accumulated and displayed by a processor in the wind tunnel control room. This report includes optical and electrical schematics, system maintenance and operation procedures.

  17. Comment on "Fringe projection profilometry with nonparallel illumination: a least-squares approach"

    NASA Astrophysics Data System (ADS)

    Wang, Zhaoyang; Bi, Hongbo

    2006-07-01

    We comment on the recent Letter by Chen and Quan [Opt. Lett.30, 2101 (2005)] in which a least-squares approach was proposed to cope with the nonparallel illumination in fringe projection profilometry. It is noted that the previous mathematical derivations of the fringe pitch and carrier phase functions on the reference plane were incorrect. In addition, we suggest that the variation of carrier phase along the vertical direction should be considered.

  18. Flexible Two-Photon Interference Fringes with Thermal Light.

    PubMed

    Cao, De-Zhong; Ren, Cheng; Ni, Jin-Yang; Zhang, Yan; Zhang, Su-Heng; Wang, Kaige

    2017-05-16

    Flexible interference patterning is an important tool for adaptable measurement precisions. We report on experimental results of controllable two-photon interference fringes with thermal light in an incoherent rotational shearing interferometer. The two incoherent beams in the interferometer are orthogonally polarized, and their wavefront distributions differ only in an angle of rotation. The spacings and directions of the two-photon interference fringes vary with the rotation angle, as illustrated in three cases of two-photon correlation measurements in experiment.

  19. Wide-view transflective liquid crystal display for mobile applications

    NASA Astrophysics Data System (ADS)

    Kim, Hyang Yul; Ge, Zhibing; Wu, Shin-Tson; Lee, Seung Hee

    2007-12-01

    A high optical efficiency and wide-view transflective liquid crystal display based on fringe-field switching structure is proposed. The transmissive part has a homogenous liquid crystal (LC) alignment and is driven by a fringe electric field, which exhibits excellent electro-optic characteristics. The reflective part has a hybrid LC alignment with quarter-wave phase retardation and is also driven by a fringe electric field. Consequently, the transmissive and reflective parts have similar gamma curves.

  20. Method and apparatus for fringe-scanning chromosome analysis

    DOEpatents

    Norgren, R.M.; Gray, J.W.; Hirschfeld, T.B.

    1983-08-31

    Apparatus and method are provided for analyzing sub-micron-sized features of microscopic particles. Two central features of the invention are (1) constraining microscopic particles to flow with substantially constant orientation through a predetermined interference fringe pattern, and (2) estimating particle structure by analyzing its fringe profile. The invention allows nearly an order of magnitude higher resolution of chromosome structure than possible with currently available flow system techniques. The invention allows rapid and accurate flow karyotyping of chromosomes.

  1. NEW APPROACHES: Demonstration of a dancing interference fringe

    NASA Astrophysics Data System (ADS)

    Kagawa, K.; Yamanaka, H.; Yokoi, S.; Hattori, H.

    1997-11-01

    A unique and amusing piece of laser art is proposed for use in physics education. It is shown that a dynamic and beautiful interference fringe can be produced when a He - Ne laser beam illuminates a droplet, which is called Brandy's tear, on a glass surface. This interference fringe can be explained in terms of the interference of multiple spherical waves scattered by the droplet. This kind of demonstration experiment is very helpful for exciting students' curiosity.

  2. Simplified paraboloid phase model-based phase tracker for demodulation of a single complex fringe.

    PubMed

    He, A; Deepan, B; Quan, C

    2017-09-01

    A regularized phase tracker (RPT) is an effective method for demodulation of single closed-fringe patterns. However, lengthy calculation time, specially designed scanning strategy, and sign-ambiguity problems caused by noise and saddle points reduce its effectiveness, especially for demodulating large and complex fringe patterns. In this paper, a simplified paraboloid phase model-based regularized phase tracker (SPRPT) is proposed. In SPRPT, first and second phase derivatives are pre-determined by the density-direction-combined method and discrete higher-order demodulation algorithm, respectively. Hence, cost function is effectively simplified to reduce the computation time significantly. Moreover, pre-determined phase derivatives improve the robustness of the demodulation of closed, complex fringe patterns. Thus, no specifically designed scanning strategy is needed; nevertheless, it is robust against the sign-ambiguity problem. The paraboloid phase model also assures better accuracy and robustness against noise. Both the simulated and experimental fringe patterns (obtained using electronic speckle pattern interferometry) are used to validate the proposed method, and a comparison of the proposed method with existing RPT methods is carried out. The simulation results show that the proposed method has achieved the highest accuracy with less computational time. The experimental result proves the robustness and the accuracy of the proposed method for demodulation of noisy fringe patterns and its feasibility for static and dynamic applications.

  3. 3D fingerprint imaging system based on full-field fringe projection profilometry

    NASA Astrophysics Data System (ADS)

    Huang, Shujun; Zhang, Zonghua; Zhao, Yan; Dai, Jie; Chen, Chao; Xu, Yongjia; Zhang, E.; Xie, Lili

    2014-01-01

    As an unique, unchangeable and easily acquired biometrics, fingerprint has been widely studied in academics and applied in many fields over the years. The traditional fingerprint recognition methods are based on the obtained 2D feature of fingerprint. However, fingerprint is a 3D biological characteristic. The mapping from 3D to 2D loses 1D information and causes nonlinear distortion of the captured fingerprint. Therefore, it is becoming more and more important to obtain 3D fingerprint information for recognition. In this paper, a novel 3D fingerprint imaging system is presented based on fringe projection technique to obtain 3D features and the corresponding color texture information. A series of color sinusoidal fringe patterns with optimum three-fringe numbers are projected onto a finger surface. From another viewpoint, the fringe patterns are deformed by the finger surface and captured by a CCD camera. 3D shape data of the finger can be obtained from the captured fringe pattern images. This paper studies the prototype of the 3D fingerprint imaging system, including principle of 3D fingerprint acquisition, hardware design of the 3D imaging system, 3D calibration of the system, and software development. Some experiments are carried out by acquiring several 3D fingerprint data. The experimental results demonstrate the feasibility of the proposed 3D fingerprint imaging system.

  4. Optical mapping of surface roughness by implementation of a spatial light modulator

    NASA Astrophysics Data System (ADS)

    Aulbach, Laura; Pöller, Franziska; Lu, Min; Wang, Shengjia; Koch, Alexander W.

    2017-08-01

    It is well-known that the surface roughness of materials plays an important role in the operation and performance of technological systems. The roughness influences key parameters, such as friction and wear, and is directly connected to the functionality and durability of the respective system. Tactile methods are widely used for the measurement of surface roughness, but a destructive measurement procedure and the lack of feasibility of online monitoring are crucial drawbacks. In the last decades, several non-contact, usually optical systems for surface roughness measurements have been developed, e.g., white light interferometry, light scatter analysis, or speckle correlation. These techniques are in turn often unable to assign the roughness to a certain surface area or involve inappropriate adjustment procedures. One promising and straightforward optical measurement method is the surface roughness measurement by analyzing the fringe visibility of an interferometric fringe pattern. In our work, we employed a spatial light modulator in the interferometric setup to vary the fringe visibility and provide a stable and reliable measurement system. In previous research, either the averaged fringe visibility or the fringe visibility along a defined observation profile were analyzed. In this article, the analysis of the fringe visibility is extended to generate a complete roughness map of the measurement target. Thus, surface defects or areas of different roughness can be easily located.

  5. On intrinsic nonlinear particle motion in compact synchrotrons

    NASA Astrophysics Data System (ADS)

    Hwang, Kyung Ryun

    Due to the low energy and small curvature characteristics of compact synchrotrons, there can be unexpected features that were not present or negligible in high energy accelerators. Nonlinear kinetics, fringe field effect, and space charge effect are those features which become important for low energy and small curvature accelerators. Nonlinear kinematics can limit the dynamics aperture for compact machine even if it consists of all linear elements. The contribution of the nonlinear kinematics on nonlinear optics parameters are first derived. As the dipole bending radius become smaller, the dipole fringe field effect become stronger. Calculation of the Lie map generator and corresponding mapping equation of dipole fringe field is presented. It is found that the higher order nonlinear potential is inverse proportional to powers of fringe field extent and correction to focusing and low order nonlinear potential is proportional to powers of fringe field extent. The fringe field also found to cause large closed orbit deviation for compact synchrotrons. The 2:1 and 4:1 space charge resonances are known to cause beam loss, emittance growth and halo formation for low energy high intensity beams. By numerical simulations, we observe a higher order 6:2 space charge resonance, which can successfully be understood by the concatenation of 2:1 and 4:1 resonances via canonical perturbation. We also develop an explicit symplectic tracking method for compact electrostatic storage rings and explore the feasibility of electric dipole moment (EDM) measurements.

  6. Gradations of awareness in a modified sequence learning task.

    PubMed

    Norman, Elisabeth; Price, Mark C; Duff, Simon C; Mentzoni, Rune A

    2007-12-01

    We argue performance in the serial reaction time (SRT) task is associated with gradations of awareness that provide examples of fringe consciousness [Mangan, B. (1993b). Taking phenomenology seriously: the "fringe" and its implications for cognitive research. Consciousness and Cognition, 2, 89-108, Mangan, B. (2003). The conscious "fringe": Bringing William James up to date. In B. J. Baars, W. P. Banks & J. B. Newman (Eds.), Essential sources in the scientific study of consciousness (pp. 741-759). Cambridge, MA: The MIT Press.], and address limitations of the traditional SRT procedure, including criticism of exclusion generation tasks. Two experiments are conducted with a modified SRT procedure where irrelevant stimulus attributes obscure the sequence rule. Our modified paradigm, which includes a novel exclusion task, makes it easier to demonstrate a previously controversial influence of response stimulus interval (RSI) on awareness. It also allows identification of participants showing fringe consciousness rather than explicit sequence knowledge, as reflected by dissociations between different awareness measures. The NEO-PI-R variable Openness to Feelings influenced the diversity of subjective feelings reported during two awareness measures, but not the degree of learning and awareness as previously found with traditional SRT tasks [Norman, E., Price, M. C., & Duff, S. C. (2006). Fringe consciousness in sequence learning: the influence of individual differences. Consciousness and Cognition, 15(4), 723-760.]. This suggests possible distinctions between two components of fringe consciousness.

  7. Adamson's Fringe, Horatio George Adamson, and Kligman's Experiments and Observations on Tinea Capitis

    PubMed Central

    Joshi, Rajiv

    2011-01-01

    Adamson's fringe is located at the upper margin of the keratogenous zone of the hair follicle where the nucleated hair shaft cornifies completely and gets converted to hard anucleated keratin. It marks also the area of complete keratinization of the cuticle and Henle's layer of the inner root sheath and the beginning of the stem of the follicle. In Tinea capitis, dermatophytic infection of the hair shaft is restricted to this zone and the fungi do not penetrate further down the infected hair in the bulb of the follicle. The fungi in Adamson's words form “a fringe of mycelium surrounding the hair shaft and project below the lower margin of the sheath of spores around the root-stem.” Horatio George Adamson (1865--1955), a British dermatologist first described this phenomenon, in 1895, and this article describes Adamson's fringe with a short biography of Adamson and discusses Kligman's experiments and observations on Tinea capitis which validated the observations of Adamson and the concept of Adamson's Fringe and described the pathogenesis in Tinea capitis. PMID:21769230

  8. Nonlinear regression method for estimating neutral wind and temperature from Fabry-Perot interferometer data.

    PubMed

    Harding, Brian J; Gehrels, Thomas W; Makela, Jonathan J

    2014-02-01

    The Earth's thermosphere plays a critical role in driving electrodynamic processes in the ionosphere and in transferring solar energy to the atmosphere, yet measurements of thermospheric state parameters, such as wind and temperature, are sparse. One of the most popular techniques for measuring these parameters is to use a Fabry-Perot interferometer to monitor the Doppler width and breadth of naturally occurring airglow emissions in the thermosphere. In this work, we present a technique for estimating upper-atmospheric winds and temperatures from images of Fabry-Perot fringes captured by a CCD detector. We estimate instrument parameters from fringe patterns of a frequency-stabilized laser, and we use these parameters to estimate winds and temperatures from airglow fringe patterns. A unique feature of this technique is the model used for the laser and airglow fringe patterns, which fits all fringes simultaneously and attempts to model the effects of optical defects. This technique yields accurate estimates for winds, temperatures, and the associated uncertainties in these parameters, as we show with a Monte Carlo simulation.

  9. Off-axis illumination direct-to-digital holography

    DOEpatents

    Thomas, Clarence E.; Price, Jeffery R.; Voelkl, Edgar; Hanson, Gregory R.

    2004-06-08

    Systems and methods are described for off-axis illumination direct-to-digital holography. A method of recording an off-axis illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis, includes: reflecting a reference beam from a reference mirror at a non-normal angle; reflecting an object beam from an object at an angle with respect to an optical axis defined by a focusing lens; focusing the reference beam and the object beam at a focal plane of a digital recorder to form the off-axis illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis; digitally recording the off-axis illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis; Fourier analyzing the recorded off-axis illuminated spatially heterodyne hologram including spatially heterodyne fringes by transforming axes of the recorded off-axis illuminated spatially heterodyne hologram including spatially heterodyne fringes in Fourier space to sit on top of a heterodyne carrier frequency defined as an angle between the reference beam and the object beam; applying a digital filter to cut off signals around an original origin; and then performing an inverse Fourier transform.

  10. Improved Goldstein Interferogram Filter Based on Local Fringe Frequency Estimation.

    PubMed

    Feng, Qingqing; Xu, Huaping; Wu, Zhefeng; You, Yanan; Liu, Wei; Ge, Shiqi

    2016-11-23

    The quality of an interferogram, which is limited by various phase noise, will greatly affect the further processes of InSAR, such as phase unwrapping. Interferometric SAR (InSAR) geophysical measurements', such as height or displacement, phase filtering is therefore an essential step. In this work, an improved Goldstein interferogram filter is proposed to suppress the phase noise while preserving the fringe edges. First, the proposed adaptive filter step, performed before frequency estimation, is employed to improve the estimation accuracy. Subsequently, to preserve the fringe characteristics, the estimated fringe frequency in each fixed filtering patch is removed from the original noisy phase. Then, the residual phase is smoothed based on the modified Goldstein filter with its parameter alpha dependent on both the coherence map and the residual phase frequency. Finally, the filtered residual phase and the removed fringe frequency are combined to generate the filtered interferogram, with the loss of signal minimized while reducing the noise level. The effectiveness of the proposed method is verified by experimental results based on both simulated and real data.

  11. Improved Goldstein Interferogram Filter Based on Local Fringe Frequency Estimation

    PubMed Central

    Feng, Qingqing; Xu, Huaping; Wu, Zhefeng; You, Yanan; Liu, Wei; Ge, Shiqi

    2016-01-01

    The quality of an interferogram, which is limited by various phase noise, will greatly affect the further processes of InSAR, such as phase unwrapping. Interferometric SAR (InSAR) geophysical measurements’, such as height or displacement, phase filtering is therefore an essential step. In this work, an improved Goldstein interferogram filter is proposed to suppress the phase noise while preserving the fringe edges. First, the proposed adaptive filter step, performed before frequency estimation, is employed to improve the estimation accuracy. Subsequently, to preserve the fringe characteristics, the estimated fringe frequency in each fixed filtering patch is removed from the original noisy phase. Then, the residual phase is smoothed based on the modified Goldstein filter with its parameter alpha dependent on both the coherence map and the residual phase frequency. Finally, the filtered residual phase and the removed fringe frequency are combined to generate the filtered interferogram, with the loss of signal minimized while reducing the noise level. The effectiveness of the proposed method is verified by experimental results based on both simulated and real data. PMID:27886081

  12. Single beam write and/or replay of spatial heterodyne holograms

    DOEpatents

    Thomas, Clarence E.; Hanson, Gregory R.

    2007-11-20

    A method of writing a spatially heterodyne hologram having spatially heterodyne fringes includes: passing a single write beam through a spatial light modulator that digitally modulates said single write beam; and focusing the single write beam at a focal plane of a lens to impose a holographic diffraction grating pattern on the photorefractive crystal, the holographic diffraction grating pattern including the spatially heterodyne hologram having spatially heterodyne fringes, wherein only said single write beam is incident on said photorefractive crystal without a reference beam. A method of replaying a spatially heterodyne hologram having spatially heterodyne fringes at a replay angle includes: illuminating a photorefractive crystal having a holographic diffraction grating with a beam from a laser at an illumination angle, the holographic diffraction grating pattern including the spatially heterodyne hologram having spatially heterodyne fringes, wherein a difference between said illumination angle and said replay angle defines a diffraction angle .alpha. that is a function of a plane wave mathematically added to original object wave phase and amplitude data of said spatially heterodyne hologram having spatially heterodyne fringes.

  13. Two-dimensional fringe probing of transient liquid temperatures in a mini space.

    PubMed

    Xue, Zhenlan; Qiu, Huihe

    2011-05-01

    A 2D fringe probing transient temperature measurement technique based on photothermal deflection theory was developed. It utilizes material's refractive index dependence on temperature gradient to obtain temperature information from laser deflection. Instead of single beam, this method applies multiple laser beams to obtain 2D temperature information. The laser fringe was generated with a Mach-Zehnder interferometer. A transient heating experiment was conducted using an electric wire to demonstrate this technique. Temperature field around a heating wire and variation with time was obtained utilizing the scattering fringe patterns. This technique provides non-invasive 2D temperature measurements with spatial and temporal resolutions of 3.5 μm and 4 ms, respectively. It is possible to achieve temporal resolution to 500 μs utilizing the existing high speed camera.

  14. Determination of skeleton and sign map for phase obtaining from a single ESPI image

    NASA Astrophysics Data System (ADS)

    Yang, Xia; Yu, Qifeng; Fu, Sihua

    2009-06-01

    A robust method of determining the sign map and skeletons for ESPI images is introduced in this paper. ESPI images have high speckle noise which makes it difficult to obtain the fringe information, especially from a single image. To overcome the effects of high speckle noise, local directional computing windows are designed according to the fringe directions. Then by calculating the gradients from the filtered image in directional windows, sign map and good skeletons can be determined robustly. Based on the sign map, single image phase-extracting methods such as quadrature transform can be improved. And based on skeletons, fringe phases can be obtained directly by normalization methods. Experiments show that this new method is robust and effective for extracting phase from a single ESPI fringe image.

  15. Spectral dispersion and fringe detection in IOTA

    NASA Technical Reports Server (NTRS)

    Traub, W. A.; Lacasse, M. G.; Carleton, N. P.

    1990-01-01

    Pupil plane beam combination, spectral dispersion, detection, and fringe tracking are discussed for the IOTA interferometer. A new spectrometer design is presented in which the angular dispersion with respect to wavenumber is nearly constant. The dispersing element is a type of grism, a series combination of grating and prism, in which the constant parts of the dispersion add, but the slopes cancel. This grism is optimized for the display of channelled spectra. The dispersed fringes can be tracked by a matched-filter photon-counting correlator algorithm. This algorithm requires very few arithmetic operations per detected photon, making it well-suited for real-time fringe tracking. The algorithm is able to adapt to different stellar spectral types, intensity levels, and atmospheric time constants. The results of numerical experiments are reported.

  16. Basic Science of the Fundamentals and Dynamics of Social-Fringe Group Formation and Sustainment

    DTIC Science & Technology

    2012-08-01

    You’re not doing well, but you’re still free to consume. We’re all equal in the eyes of the market." - Stuart Hall 011 the 2011 London Riots Case 3...culture!to!another.!!!Overall,(it(focussed(on(the(persuasive(nature,( influence(and(propagation(of(compelling(ideas,(the(bases(for(group( receptiveness (and...recruitment&and&fringe&group&formation& o What!are!the!personality!and!social!characteristics!of!adherents!that! increase!their! receptiveness !to!fringe!ideas

  17. Simulating interfering fringe displacements by lateral shifts of a camera for educational purposes

    NASA Astrophysics Data System (ADS)

    Rivera-Ortega, Uriel

    2018-07-01

    In this manuscript we propose a simple method to emulate fringe displacements in a fringe pattern, due to the interference of two plane waves, by using lateral shifts of a CMOS detector under the scheme of a Twyman–Green interferometric setup, avoiding unwanted vibrations and the need for specific and expensive devices in order to accomplish the task. The simplicity of the proposed experimental setup allows it to be easily replicated and used for teaching or demonstrative purposes, essentially for undergraduate students.

  18. Laser angle measurement system

    NASA Technical Reports Server (NTRS)

    Pond, C. R.; Texeira, P. D.; Wilbert, R. E.

    1980-01-01

    The design and fabrication of a laser angle measurement system is described. The instrument is a fringe counting interferometer that monitors the pitch attitude of a model in a wind tunnel. A laser source and detector are mounted above the mode. Interference fringes are generated by a small passive element on the model. The fringe count is accumulated and displayed by a processor in the wind tunnel control room. Optical and electrical schematics, system maintenance and operation procedures are included, and the results of a demonstration test are given.

  19. Mechanisms of Cottonwood Establishment in Gravel-Bed Rivers, across Scales from the Bar to the Reach

    NASA Astrophysics Data System (ADS)

    Meier, C. I.

    2017-12-01

    Riparian cottonwoods are pioneer trees adapted to colonizing fluvial corridors, with strong effects on ecosystem structure and function. As their populations are being affected by flow alterations and invasive species, their recruitment mechanisms need to be understood, to support scientifically-based restoration efforts. I propose new concepts for cottonwood establishment in gravelly streams, from the local to the reach scale. These notions complement the currently-accepted ideas, which apply only to the landscape scale, and whose basic assumptions (existence of an alluvial water table, which is planar, almost horizontal, and linked to the river stage, with a parallel, spatially-uniform capillary fringe) seem to be based on a physical template that is only valid in the case of sand-bed streams. At the local, within-the-bar scale, two concepts drive establishment success. First, a finer matrix material helps retain more capillary water after the yearly snowmelt flood or a precipitation event. Second, the coarse surface layer of clean gravel and cobble acts as rock mulch, strongly decreasing evaporative losses. At the reach scale, we find that the commonly reported arcuate bands of cottonwoods do not depend on groundwater, but are caused by water dispersal (hydrochory). Wind-dispersed seeds fall into the river, are entrained into the drift, and start germinating as they travel under water. Some of the seeds and germinants find their way into the shallow, high relative roughness flow along the cobble shoreline. They are able to deposit in this environment, where they start growing, also under water. As waters recede, during the period of seed availability in the drift, the river seeds its banks and bars. Thus, the boundaries of observed bands and patches with successful seedling recruitment correspond to the location of flow profiles at different dates during the flood recession.

  20. Groundwater discharge by evapotranspiration, flow of water in unsaturated soil, and stable isotope water sourcing in areas of sparse vegetation, Amargosa Desert, Nye County, Nevada

    USGS Publications Warehouse

    Moreo, Michael T.; Andraski, Brian J.; Garcia, C. Amanda

    2017-08-29

    This report documents methodology and results of a study to evaluate groundwater discharge by evapotranspiration (GWET) in sparsely vegetated areas of Amargosa Desert and improve understanding of hydrologic-continuum processes controlling groundwater discharge. Evapotranspiration and GWET rates were computed and characterized at three sites over 2 years using a combination of micrometeorological, unsaturated zone, and stable-isotope measurements. One site (Amargosa Flat Shallow [AFS]) was in a sparse and isolated area of saltgrass (Distichlis spicata) where the depth to groundwater was 3.8 meters (m). The second site (Amargosa Flat Deep [AFD]) was in a sparse cover of predominantly shadscale (Atriplex confertifolia) where the depth to groundwater was 5.3 m. The third site (Amargosa Desert Research Site [ADRS]), selected as a control site where GWET is assumed to be zero, was located in sparse vegetation dominated by creosote bush (Larrea tridentata) where the depth to groundwater was 110 m.Results indicated that capillary rise brought groundwater to within 0.9 m (at AFS) and 3 m (at AFD) of land surface, and that GWET rates were largely controlled by the slow but relatively persistent upward flow of water through the unsaturated zone in response to atmospheric-evaporative demands. Greater GWET at AFS (50 ± 20 millimeters per year [mm/yr]) than at AFD (16 ± 15 mm/yr) corresponded with its shallower depth to the capillary fringe and constantly higher soil-water content. The stable-isotope dataset for hydrogen (δ2H) and oxygen (δ18O) illustrated a broad range of plant-water-uptake scenarios. The AFS saltgrass and AFD shadscale responded to changing environmental conditions and their opportunistic water use included the time- and depth-variable uptake of unsaturated-zone water derived from a combination of groundwater and precipitation. These results can be used to estimate GWET in other areas of Amargosa Desert where hydrologic conditions are similar.

  1. 29 CFR 4.162 - Fringe benefits under contracts exceeding $2,500.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... insurance, disability and sickness insurance, accident insurance, vacation and holiday pay, costs of... at a time subsequent to the award but before completion of the contract. Such fringe benefit...

  2. 29 CFR 4.162 - Fringe benefits under contracts exceeding $2,500.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... insurance, disability and sickness insurance, accident insurance, vacation and holiday pay, costs of... at a time subsequent to the award but before completion of the contract. Such fringe benefit...

  3. Express bus-fringe parking planning methodology.

    DOT National Transportation Integrated Search

    1975-01-01

    The conception, calibration, and evaluation of alternative disaggregate behavioral models of the express bus-fringe parking travel choice situation are described. Survey data collected for the Parham Express Service in Richmond, Virginia, are used to...

  4. Automatic evaluation of interferograms

    NASA Technical Reports Server (NTRS)

    Becker, F.

    1982-01-01

    A system for the evaluation of interference patterns was developed. For digitizing and processing of the interferograms from classical and holographic interferometers a picture analysis system based upon a computer with a television digitizer was installed. Depending on the quality of the interferograms, four different picture enhancement operations may be used: Signal averaging; spatial smoothing, subtraction of the overlayed intensity function and the removal of distortion-patterns using a spatial filtering technique in the frequency spectrum of the interferograms. The extraction of fringe loci from the digitized interferograms is performed by a foating-threshold method. The fringes are numbered using a special scheme after the removal of any fringe disconnections which appeared if there was insufficient contrast in the holograms. The reconstruction of the object function from the fringe field uses least squares approximation with spline fit. Applications are given.

  5. Application of digital holographic interferometry to pressure measurements of symmetric, supercritical and circulation-control airfoils in transonic flow fields

    NASA Technical Reports Server (NTRS)

    Torres, Francisco J.

    1987-01-01

    Six airfoil interferograms were evaluated using a semiautomatic image-processor system which digitizes, segments, and extracts the fringe coordinates along a polygonal line. The resulting fringe order function was converted into density and pressure distributions and a comparison was made with pressure transducer data at the same wind tunnel test conditions. Three airfoil shapes were used in the evaluation to test the capabilities of the image processor with a variety of flows. Symmetric, supercritical, and circulation-control airfoil interferograms provided fringe patterns with shocks, separated flows, and high-pressure regions for evaluation. Regions along the polygon line with very clear fringe patterns yielded results within 1% of transducer measurements, while poorer quality regions, particularly near the leading and trailing edges, yielded results that were not as good.

  6. Measurement of the configuration of a concave surface by the interference of reflected light

    NASA Technical Reports Server (NTRS)

    Kumazawa, T.; Sakamoto, T.; Shida, S.

    1985-01-01

    A method whereby a concave surface is irradiated with coherent light and the resulting interference fringes yield information on the concave surface is described. This method can be applied to a surface which satisfies the following conditions: (1) the concave face has a mirror surface; (2) the profile of the face is expressed by a mathematical function with a point of inflection. In this interferometry, multilight waves reflected from the concave surface interfere and make fringes wherever the reflected light propagates. Interference fringe orders. Photographs of the fringe patterns for a uniformly loaded thin silicon plate clamped at the edge are shown experimentally. The experimental and the theoretical values of the maximum optical path difference show good agreement. This simple method can be applied to obtain accurate information on concave surfaces.

  7. Fringe periods of color moirés in contact-type 3-D displays.

    PubMed

    Lee, Hyoung; Kim, Sung-Kyu; Sohn, Kwanghoon; Son, Jung-Young; Chernyshov, Oleksii O

    2016-06-27

    A mathematical formula of calculating the fringe periods of the color moirés appearing at the contact-type 3-D displays is derived. It is typical that the color moirés are chirped and the period of the line pattern in viewing zone forming optics is more than two times of that of the pixel pattern in the display panel. These make impossible to calculate the fringe periods of the color moirés with the conventional beat frequency formula. The derived formula work very well for any combination of two line patterns having either a same line period or different line periods. This is experimentally proved. Furthermore, it is also shown that the fringe period can be expressed in terms of the viewing distance and focal length of the viewing zone forming optics.

  8. Ghost fringe removal techniques using Lissajous data presentation

    DOE PAGES

    Erskine, David J.; Eggert, J. H.; Celliers, P. M.; ...

    2016-03-14

    A VISAR (Velocity Interferometer System for Any Reflector) is a Dopplervelocity interferometer which is an important optical diagnostic in shockwave experiments at the national laboratories, used to measureequation of state(EOS) of materials under extreme conditions. Unwanted reflection of laser light from target windows can produce an additional component to the VISAR fringe record that can distort and obscure the true velocity signal. When accurately removing this so-called ghost artifact component is essential for achieving high accuracy EOSmeasurements, especially when the true light signal is only weakly reflected from the shock front. Independent of the choice of algorithm for processing themore » raw data into a complex fringe signal, we have found it beneficial to plot this signal as a Lissajous and seek the proper center of this path, even under time varying intensity which can shift the perceived center. Moreover, the ghost contribution is then solved by a simple translation in the complex plane that recenters the Lissajous path. For continuous velocity histories, we find that plotting the fringe magnitude vs nonfringing intensity and optimizing linearity is an invaluable tool for determining accurate ghost offsets. For discontinuous velocity histories, we have developed graphically inspired methods which relate the results of two VISARs having different velocity per fringe proportionalities or assumptions of constant fringe magnitude to find the ghost offset. The technique can also remove window reflection artifacts in generic interferometers, such as in the metrology of surfaces.« less

  9. Examination of tear film smoothness on corneae after refractive surgeries using a noninvasive interferometric method

    NASA Astrophysics Data System (ADS)

    Szczesna, Dorota H.; Kulas, Zbigniew; Kasprzak, Henryk T.; Stenevi, Ulf

    2009-11-01

    A lateral shearing interferometer was used to examine the smoothness of the tear film. The information about the distribution and stability of the precorneal tear film is carried out by the wavefront reflected from the surface of tears and coded in interference fringes. Smooth and regular fringes indicate a smooth tear film surface. On corneae after laser in situ keratomileusis (LASIK) or radial keratotomy (RK) surgery, the interference fringes are seldom regular. The fringes are bent on bright lines, which are interpreted as tear film breakups. The high-intensity pattern seems to appear in similar location on the corneal surface after refractive surgery. Our purpose was to extract information about the pattern existing under the interference fringes and calculate its shape reproducibility over time and following eye blinks. A low-pass filter was applied and correlation coefficient was calculated to compare a selected fragment of the template image to each of the following frames in the recorded sequence. High values of the correlation coefficient suggest that irregularities of the corneal epithelium might influence tear film instability and that tear film breakup may be associated with local irregularities of the corneal topography created after the LASIK and RK surgeries.

  10. Telecentric 3D profilometry based on phase-shifting fringe projection.

    PubMed

    Li, Dong; Liu, Chunyang; Tian, Jindong

    2014-12-29

    Three dimensional shape measurement in the microscopic range becomes increasingly important with the development of micro manufacturing technology. Microscopic fringe projection techniques offer a fast, robust, and full-field measurement for field sizes from approximately 1 mm2 to several cm2. However, the depth of field is very small due to the imaging of non-telecentric microscope, which is often not sufficient to measure the complete depth of a 3D-object. And the calibration of phase-to-depth conversion is complicated which need a precision translation stage and a reference plane. In this paper, we propose a novel telecentric phase-shifting projected fringe profilometry for small and thick objects. Telecentric imaging extends the depth of field approximately to millimeter order, which is much larger than that of microscopy. To avoid the complicated phase-to-depth conversion in microscopic fringe projection, we develop a new system calibration method of camera and projector based on telecentric imaging model. Based on these, a 3D reconstruction of telecentric imaging is presented with stereovision aided by fringe phase maps. Experiments demonstrated the feasibility and high measurement accuracy of the proposed system for thick object.

  11. The effect of pneumatophore density on turbulence: A field study in a Sonneratia-dominated mangrove forest, Vietnam

    NASA Astrophysics Data System (ADS)

    Norris, Benjamin K.; Mullarney, Julia C.; Bryan, Karin R.; Henderson, Stephen M.

    2017-09-01

    This paper examines the role of mangrove pneumatophore roots as a spatial control over the turbulent kinetic energy (TKE) dissipation rate within a natural mangrove forest. Measurements of turbulence at millimeter scales were compared with vegetation geometries reconstructed using a novel photogrammetric technique. These small-scale relationships were then averaged to show larger-scale patterns in turbulence across the mudflat and mangrove fringe-forest transition. Although turbulence estimates varied with across-shore position, TKE dissipation was always elevated in the fringe relative to mudflat and forest interior sample sites. The largest dissipation rates (4.5 × 10-3 W kg-1) were measured as breaking waves propagated over canopies in very shallow water. Dissipation was reduced, but often remained intense (10-5-10-4 W kg-1) under non-breaking waves at the fringe, likely indicating turbulent generation in pneumatophore wakes. Pneumatophore density was positively correlated with the spatial distribution of TKE dissipation. Turbulence was also correlated positively with wave height and negatively with water depth. Fringe sediments were more sandy and less muddy than sediments onshore and offshore, suggesting that the intense turbulence may lead to winnowing of fine-grained sediments at the fringe.

  12. Highly noise-tolerant hybrid algorithm for phase retrieval from a single-shot spatial carrier fringe pattern

    NASA Astrophysics Data System (ADS)

    Dong, Zhichao; Cheng, Haobo

    2018-01-01

    A highly noise-tolerant hybrid algorithm (NTHA) is proposed in this study for phase retrieval from a single-shot spatial carrier fringe pattern (SCFP), which effectively combines the merits of spatial carrier phase shift method and two dimensional continuous wavelet transform (2D-CWT). NTHA firstly extracts three phase-shifted fringe patterns from the SCFP with one pixel malposition; then calculates phase gradients by subtracting the reference phase from the other two target phases, which are retrieved respectively from three phase-shifted fringe patterns by 2D-CWT; finally, reconstructs the phase map by a least square gradient integration method. Its typical characters include but not limited to: (1) doesn't require the spatial carrier to be constant; (2) the subtraction mitigates edge errors of 2D-CWT; (3) highly noise-tolerant, because not only 2D-CWT is noise-insensitive, but also the noise in the fringe pattern doesn't directly take part in the phase reconstruction as in previous hybrid algorithm. Its feasibility and performances are validated extensively by simulations and contrastive experiments to temporal phase shift method, Fourier transform and 2D-CWT methods.

  13. Confessions of an iconoclast: at home on the fringe.

    PubMed

    Loevinger, Jane

    2002-04-01

    The career of a psychologist whose work has been on the fringe of psychometrics, of personality theory, and, at a stretch, of psychoanalytic theory and the philosophy of science is described in this article.

  14. An optoelectronic system for fringe pattern analysis

    NASA Astrophysics Data System (ADS)

    Sciammarella, C. A.; Ahmadshahi, M.

    A system capable of retrieving and processing information recorded in fringe patterns is reported. The principal components are described as well as the architecture in which they are assembled. An example of application is given.

  15. Automatic Fringe Detection for Oil Film Interferometry Measurement of Skin Friction

    NASA Technical Reports Server (NTRS)

    Naughton, Jonathan W.; Decker, Robert K.; Jafari, Farhad

    2001-01-01

    This report summarizes two years of work on investigating algorithms for automatically detecting fringe patterns in images acquired using oil-drop interferometry for the determination of skin friction. Several different analysis methods were tested, and a combination of a windowed Fourier transform followed by a correlation was found to be most effective. The implementation of this method is discussed and details of the process are described. The results indicate that this method shows promise for automating the fringe detection process, but further testing is required.

  16. Broad source fringe formation with a Fresnel biprism and a Mach-Zehnder interferometer.

    PubMed

    Leon, S C

    1987-12-15

    A biprism is used to combine identical spatially incoherent wavefronts that have been split by an amplitude splitting interferometer such as the Mach-Zehnder. The performance of this composite interferometer is evaluated by tracing the chief ray through parallel optical systems using Snell's law and trigonometry. Fringes formed in spatially incoherent light with this optical system are compared with those formed using the Mach-Zehnder and grating interferometers. It is shown that the combination can exhibit extended source fringe formation capability greatly exceeding that of the Mach-Zehnder interferometer.

  17. Serial number coding and decoding by laser interference direct patterning on the original product surface for anti-counterfeiting.

    PubMed

    Park, In-Yong; Ahn, Sanghoon; Kim, Youngduk; Bae, Han-Sung; Kang, Hee-Shin; Yoo, Jason; Noh, Jiwhan

    2017-06-26

    Here, we investigate a method to distinguish the counterfeits by patterning multiple reflective type grating directly on the surface of the original product and analyze the serial number from its rotation angles of diffracted fringes. The micro-sized gratings were fabricated on the surface of the material at high speeds by illuminating the interference fringe generated by passing a high-energy pulse laser through the Fresnel biprism. In addition, analysis of the grating's diffraction fringes was performed using a continuous wave laser.

  18. Vapor sensors using porous silicon-based optical interferometers

    NASA Astrophysics Data System (ADS)

    Gao, Ting

    The ability to detect or monitor various gases is important for many applications. Smaller, more portable, lower power, and less expensive gas sensors are needed. Porous silicon (PS) has attracted attention for use in such devices due to its unique optical and electronic properties and its large surface area. This thesis describes the preparation and characteristics of vapor sensors using thin PS Fabry-Perot films. The average refractive index of the PS layer increases when the PS film is exposed to analyte vapors, causing the optical fringes to shift to longer wavelengths. Two methods for monitoring the shifts in these optical fringes are explored in this thesis. The first technique measures the reflection spectrum using a white light source, and the second measures the intensity of reflected light using a low-power red diode laser source. The latter method offers a simple, low-cost and reliable transduction mechanism for vapor sensing. A vapor sensor with a detection limit of 250 ppb and a wide dynamic range (five orders of magnitude) is demonstrated. The effect of the PS film thickness and porosity on sensitivity are systematically studied. A model based on the Bruggeman approximation and capillary condensation is proposed to explain this sensing behavior. Two approaches to improve the sensitivity of the PS sensors are explored. In the first, porous Si is chemically modified and the investigation shows that the sensing response varies with different surface properties. In a second study, thin polymer layers are coated on the porous Si substrate to selectively filter solvent vapors. This bi-layer approach is also applied to porous Si layers that have luminescent quantum structures. These latter structures sense adsorbates based on quenching of luminescence from the quantum-confined silicon nanostructures. In the course of this thesis, an anomalous response of ozone-oxidized PS films to water vapor was discovered. The effect was studied by optical interferometry, isotope studies, and in-situ Fourier transform infrared spectroscopy. It is concluded that in some porous Si films, water forms a strongly hydrogen bonded network that results in compression of the porous Si layer.

  19. An Externally Dispersed Interferometer for Sensitive Doppler Extrasolar Planet Searches

    NASA Astrophysics Data System (ADS)

    Ge, Jian; Erskine, David J.; Rushford, Mike

    2002-09-01

    A new kind of instrument for sensitive Doppler extrasolar planet searches, called an externally dispersed interferometer, is described in this paper. It is a combination of an optical Michelson-type interferometer and an intermediate-resolution grating spectrometer. The interferometer measures Doppler radial velocity (RV) variations of starlight through the phase shifts of moiré fringes, created by multiplication of the interferometer fringes with stellar absorption lines. The intermediate-resolution spectrograph disperses the moiré fringes into thousands of parallel-wavelength channels. This increases the instrument bandwidth and fringe visibility by preventing fringe cross-talk between neighboring spectral lines. This results in a net increase in the signal-to-noise ratio over an interferometer used alone with broadband light. Compared to current echelle spectrometers for extrasolar planet searches, this instrument offers two unique instrument properties: a simple, stable, well-defined sinusoidal instrument response function (point-spread function) and magnification of Doppler motion through moiré fringe techniques. Since instrument noise is chiefly limited by the ability to characterize the instrument response, this new technique provides unprecedented low instrumental noise in an economical compact apparatus, enabling higher precision for Doppler RV measurements. In practice, the moiré magnification can be 5-10 times depending on the interferometer comb angle. This instrument has better sensitivity for smaller Doppler shifts than echelle spectrometers. The instrument can be designed with much lower spectral resolving power without losing Doppler sensitivity and optimized for higher throughput than echelle spectrometers to allow a potential survey for planets around fainter stars than current magnitude limits. Lab-based experiments with a prototype instrument with a spectral resolution of R~20,000 demonstrated ~0.7 m s-1 precision for short-term RV measurements. A fiber-fed version of the prototype with R~5600 was tested with starlight at the Lick 1 m telescope and demonstrated ~7 m s-1 RV precision at 340 Å bandwidth. The increased velocity noise is attributed to the lower spectral resolution, lower fringe visibility, and uncontrolled instrument environment.

  20. Applications manual for logit modes of express bus-fringe parking choices.

    DOT National Transportation Integrated Search

    1976-01-01

    Manual computations and computerized applications of logit models are described. The models demonstrated reflect travel behavior concerning express bus-fringe parking transit. The specific travel issues addressed include the basic automobile vs. expr...

  1. A procedural method for express bus-fringe parking transit planning.

    DOT National Transportation Integrated Search

    1976-01-01

    The report illustrates a procedural method for planning express bus-fringe parking transit services - a method built upon the findings from previous research, including disaggregate travel choice models and planning guidelines. The methodology addres...

  2. The Fringe-Imaging Skin Friction Technique PC Application User's Manual

    NASA Technical Reports Server (NTRS)

    Zilliac, Gregory G.

    1999-01-01

    A personal computer application (CXWIN4G) has been written which greatly simplifies the task of extracting skin friction measurements from interferograms of oil flows on the surface of wind tunnel models. Images are first calibrated, using a novel approach to one-camera photogrammetry, to obtain accurate spatial information on surfaces with curvature. As part of the image calibration process, an auxiliary file containing the wind tunnel model geometry is used in conjunction with a two-dimensional direct linear transformation to relate the image plane to the physical (model) coordinates. The application then applies a nonlinear regression model to accurately determine the fringe spacing from interferometric intensity records as required by the Fringe Imaging Skin Friction (FISF) technique. The skin friction is found through application of a simple expression that makes use of lubrication theory to relate fringe spacing to skin friction.

  3. Fringe projection application for surface variation analysis on helical shaped silicon breast

    NASA Astrophysics Data System (ADS)

    Vairavan, R.; Ong, N. R.; Sauli, Z.; Shahimin, M. M.; Kirtsaeng, S.; Sakuntasathien, S.; Alcain, J. B.; Paitong, P.; Retnasamy, V.

    2017-09-01

    Breast carcinoma is rated as a second collective cause of cancer associated death among adult females. Detection of the disease at an early stage would enhance the chance for survival. Established detection methods such as mammography, ultrasound and MRI are classified as non invasive breast cancer detection modality, but however they are not entire non-invasive as physical contact still occurs to the breast. Thus requirement for a complete non invasive and non contact is evident. Therefore, in this work, a novel application of digital fringe projection for early detection of breast cancer based on breast surface analysis is reported. Phase shift fringe projection technique and pixel tracing method was utilized to analyze the breast surface change due to the incidence of breast lump. Results have shown that the digital fringe projection is capable in detecting the existence of 1 cm sized lump within the breast sample.

  4. 3D absolute shape measurement of live rabbit hearts with a superfast two-frequency phase-shifting technique

    PubMed Central

    Wang, Yajun; Laughner, Jacob I.; Efimov, Igor R.; Zhang, Song

    2013-01-01

    This paper presents a two-frequency binary phase-shifting technique to measure three-dimensional (3D) absolute shape of beating rabbit hearts. Due to the low contrast of the cardiac surface, the projector and the camera must remain focused, which poses challenges for any existing binary method where the measurement accuracy is low. To conquer this challenge, this paper proposes to utilize the optimal pulse width modulation (OPWM) technique to generate high-frequency fringe patterns, and the error-diffusion dithering technique to produce low-frequency fringe patterns. Furthermore, this paper will show that fringe patterns produced with blue light provide the best quality measurements compared to fringe patterns generated with red or green light; and the minimum data acquisition speed for high quality measurements is around 800 Hz for a rabbit heart beating at 180 beats per minute. PMID:23482151

  5. Imaging height fluctuations in free-standing graphene membranes

    NASA Astrophysics Data System (ADS)

    Dorsey, Kyle; Miskin, Marc; Barnard, Arthur; Rose, Peter; Cohen, Itai; McEuen, Paul

    We present a technique based on multi-wavelength interference microscopy to measure the heights of observed ripples in free-standing graphene membranes. Graphene membranes released from a transparent substrate produce interference fringes when viewed in the reflection mode of an inverted microscope(Blees et. al. Nature 524 (7564): 204-207 (2015)). The fringes correspond to corrugation of the membrane as it floats near an interface. A single set of fringes is insufficient to uniquely determine the height profile, as a given fringe spacing can correspond to an increase or decrease in height by λ / 2 . Imaging at multiple wavelengths resolves the ambiguities in phase, and enables unique determination of the height profile of the membrane (Schilling et. al.Phys. Rev. E, 69:021901, 2004). We utilize this technique to map out the height fluctuations in free-standing graphene membranes to answer questions about fundamental mechanical properties of two-dimensional materials.

  6. Distance measurement using frequency scanning interferometry with mode-hoped laser

    NASA Astrophysics Data System (ADS)

    Medhat, M.; Sobee, M.; Hussein, H. M.; Terra, O.

    2016-06-01

    In this paper, frequency scanning interferometry is implemented to measure distances up to 5 m absolutely. The setup consists of a Michelson interferometer, an external cavity tunable diode laser, and an ultra-low expansion (ULE) Fabry-Pérot (FP) cavity to measure the frequency scanning range. The distance is measured by acquiring simultaneously the interference fringes from, the Michelson and the FP interferometers, while scanning the laser frequency. An online fringe processing technique is developed to calculate the distance from the fringe ratio while removing the parts result from the laser mode-hops without significantly affecting the measurement accuracy. This fringe processing method enables accurate distance measurements up to 5 m with measurements repeatability ±3.9×10-6 L. An accurate translation stage is used to find the FP cavity free-spectral-range and therefore allow accurate measurement. Finally, the setup is applied for the short distance calibration of a laser distance meter (LDM).

  7. Two-dimensional wavelet transform for reliability-guided phase unwrapping in optical fringe pattern analysis.

    PubMed

    Li, Sikun; Wang, Xiangzhao; Su, Xianyu; Tang, Feng

    2012-04-20

    This paper theoretically discusses modulus of two-dimensional (2D) wavelet transform (WT) coefficients, calculated by using two frequently used 2D daughter wavelet definitions, in an optical fringe pattern analysis. The discussion shows that neither is good enough to represent the reliability of the phase data. The differences between the two frequently used 2D daughter wavelet definitions in the performance of 2D WT also are discussed. We propose a new 2D daughter wavelet definition for reliability-guided phase unwrapping of optical fringe pattern. The modulus of the advanced 2D WT coefficients, obtained by using a daughter wavelet under this new daughter wavelet definition, includes not only modulation information but also local frequency information of the deformed fringe pattern. Therefore, it can be treated as a good parameter that represents the reliability of the retrieved phase data. Computer simulation and experimentation show the validity of the proposed method.

  8. Deformation measurement for a rotating deformable lap based on inverse fringe projection

    NASA Astrophysics Data System (ADS)

    Liao, Min; Zhang, Qican

    2015-03-01

    The active deformable lap (also namely stressed lap) is an efficient polishing tool in optical manufacturing. To measure the dynamic deformation caused by outside force on a deformable lap is important and helpful to the opticians to ensure the performance of a deformable lap as expected. In this paper, a manual deformable lap was designed to simulate the dynamic deformation of an active stressed lap, and a measurement system was developed based on inverse projected fringe technique to restore the 3D shape. A redesigned inverse fringe has been projected onto the surface of the measured lap, and the deformations of the tested lap become much obvious and can be easily and quickly evaluated by Fourier fringe analysis. Compared with the conventional projection, this technique is more obvious, and it should be a promising one in the deformation measurement of the active stressed lap in optical manufacturing.

  9. Fringe Land Use Guide and Street Plan

    DOT National Transportation Integrated Search

    1999-01-01

    The Fringe Land Use Guide and Transportation Plan has been developed over the : past two years by the F-M Metropolitan Council of Governments. One of : the primary purposes of the project was to extend arterial and collector street : planning beyond ...

  10. Evaluation of the Greenwood Drive fringe parking facility.

    DOT National Transportation Integrated Search

    1978-01-01

    The application of a procedural method for planning express bus-fringe parking transit to determine why the Greenwood Drive service in Portsmouth, Virginia, failed to attract more riders than it did is described. The analysis of the study area reveal...

  11. Brewster-plate spoiler - A novel method for reducing the amplitude of interference fringes that limit tunable-laser absorption sensitivities

    NASA Technical Reports Server (NTRS)

    Webster, C. R.

    1985-01-01

    A simple method is described for substantially reducing the amplitude of interference fringes that limit the sensitivities of tunable-laser high-resolution absorption spectrometers. A lead-salt diode laser operating in the 7-micron region is used with a single Brewster-plate spoiler to reduce the fringe amplitude by a factor of 30 and also to allow the detection of absorptances 0.001 percent in a single laser scan without subtraction techniques, without complex frequency modulation, and without distortion of the molecular line-shape signals. Application to multipass-cell spectrometers is described.

  12. SIM PlanetQuest Spectral Calibration Development Unit Beam Combiner

    NASA Technical Reports Server (NTRS)

    Tang, Hong

    2008-01-01

    The beam combiner of an astronomical long-baseline interferometer combines the two beams of starlight to form white-light fringes. We describe beam combiner in the SIM PlanetQuest Spectral Calibration Development Unit (SCDU). In addition to forming white light fringes, the beam combiner provides other functions such as separating the light for guiding, fringe tracking, and science measurement. It is designed to function over the optical bandpass 450-950 nm. Coating design is critical to beam combiner as residual dispersion and mismatches affect the ability to accurately measure the position of stars of varying spectral types.

  13. Mode power distribution effect in white-light multimode fiber extrinsic Fabry-Perot interferometric sensor systems.

    PubMed

    Han, Ming; Wang, Anbo

    2006-05-01

    Theoretical and experimental results have shown that mode power distribution (MPD) variations could significantly vary the phase of spectral fringes from multimode fiber extrinsic Fabry-Perot interferometric (MMF-EFPI) sensor systems, owing to the fact that different modes introduce different extra phase shifts resulting from the coupling of modes reflected at the second surface to the lead-in fiber end. This dependence of fringe pattern on MPD could cause measurement errors in signal demodulation methods of white-light MMF-EFPI sensors that implement the phase information of the fringes.

  14. High-efficiency holograms fixed in lithium niobate after recording using a digital fringe stabilization system.

    PubMed

    Arizmendi, Luis; Ambite, Emilio J

    2012-02-20

    We used a digital feedback control loop system to produce reproducible fixed volume transmission holograms of high diffraction efficiency. Different strategies were investigated to obtain holograms of good quality and the highest refractive index modulation depth. Using this control system, we were able to record holograms with stationary fringes. Additionally to using the stationary fringe recording, a double recording-fixing schedule resulted in being the most appropriate one to produce reproducible holograms of better characteristics. This strategy is discussed and compared with other already established ones. © 2012 Optical Society of America

  15. Combined dispersive/interference spectroscopy for producing a vector spectrum

    DOEpatents

    Erskine, David J.

    2002-01-01

    A method of measuring the spectral properties of broadband waves that combines interferometry with a wavelength disperser having many spectral channels to produce a fringing spectrum. Spectral mapping, Doppler shifts, metrology of angles, distances and secondary effects such as temperature, pressure, and acceleration which change an interferometer cavity length can be measured accurately by a compact instrument using broadband illumination. Broadband illumination avoids the fringe skip ambiguities of monochromatic waves. The interferometer provides arbitrarily high spectral resolution, simple instrument response, compactness, low cost, high field of view and high efficiency. The inclusion of a disperser increases fringe visibility and signal to noise ratio over an interferometer used alone for broadband waves. The fringing spectrum is represented as a wavelength dependent 2-d vector, which describes the fringe amplitude and phase. Vector mathematics such as generalized dot products rapidly computes average broadband phase shifts to high accuracy. A Moire effect between the interferometer's sinusoidal transmission and the illumination heterodynes high resolution spectral detail to low spectral detail, allowing the use of a low resolution disperser. Multiple parallel interferometer cavities of fixed delay allow the instantaneous mapping of a spectrum, with an instrument more compact for the same spectral resolution than a conventional dispersive spectrometer, and not requiring a scanning delay.

  16. Fringing field effects in negative capacitance field-effect transistors with a ferroelectric gate insulator

    NASA Astrophysics Data System (ADS)

    Hattori, Junichi; Fukuda, Koichi; Ikegami, Tsutomu; Ota, Hiroyuki; Migita, Shinji; Asai, Hidehiro; Toriumi, Akira

    2018-04-01

    We study the effects of fringing electric fields on the behavior of negative-capacitance (NC) field-effect transistors (FETs) with a silicon-on-insulator body and a gate stack consisting of an oxide film, an internal metal film, a ferroelectric film, and a gate electrode using our own device simulator that can properly handle the complicated relationship between the polarization and the electric field in ferroelectric materials. The behaviors of such NC FETs and the corresponding metal-oxide-semiconductor (MOS) FETs are simulated and compared with each other to evaluate the effects of the NC of the ferroelectric film. Then, the fringing field effects are evaluated by comparing the NC effects in NC FETs with and without gate spacers. The fringing field between the gate stack, especially the internal metal film, and the source/drain region induces more charges at the interface of the film with the ferroelectric film. Accordingly, the function of the NC to modulate the gate voltage and the resulting function to improve the subthreshold swing are enhanced. We also investigate the relationships of these fringing field effects to the drain voltage and four design parameters of NC FETs, i.e., gate length, gate spacer permittivity, internal metal film thickness, and oxide film thickness.

  17. Dynamics of a fringe mangrove forest detected by Landsat images in the Mekong delta, Vietnam

    NASA Astrophysics Data System (ADS)

    Fagherazzi, S.; Nardin, W.; Woodcock, C. E.; Locatelli, S.; Rulli, M. C.; Pasquarella, V. J.

    2016-02-01

    Mangrove forests dominate many tropical coastlines and are one of the most bio-diverse and productive environments on Earth. However, little is known of the large scale dynamics of mangrove canopies and how they colonize intertidal areas. Here we focus on a fringe mangrove forest located in the Mekong delta, Vietnam, a fast prograding shoreline where mangroves are encroaching tidal flats. The spatial and temporal evolution of the mangrove canopy is studied using a time series of Landsat images spanning two decades as well as Shuttle Radar Topography Mission (SRTM) elevation data. Our results show that fast mangrove expansion is followed by an increase in Normalized Difference Vegetation Index (NDVI) in the newly established canopy. We observe two different dynamics of the mangrove fringe: near the mouth of the rivers where the fringe boundary is linear the canopy expands uniformly on the tidal flats with a high colonization rate and high NDVI values. Far from the river mouths the fringe boundary is highly irregular and mangroves expansion in characterized by sparse vegetated patches displaying low NDVI values. We conclude that high NDVI values and a regular vegetation-water interface are indicative of stable mangrove canopies undergoing expansion, and therefore of resilient coastlines. In the Mekong delta these area are more likely located near a river mouth.

  18. Examination of in vivo tear film stability after eye blink and eye drying

    NASA Astrophysics Data System (ADS)

    Szczesna, Dorota H.; Kulas, Zbigniew; Kasprzak, Henryk T.; Stenevi, Ulf

    2007-07-01

    The purpose of this study is to investigate the kinetics of precorneal tear film stabilization process after eye blink and the process of creating the break-up of the tear film layer. The tear film of patients were examined in vivo by used the lateral shearing interferometer. The information about the distribution and stability of the tear film over the cornea is carried by the wave front reflected from the surface of tears and coded in interference fringes. Smooth and regular fringes indicate the smooth surface of tears over the cornea. Immediately after eye blink the interference fringes are observed on background of bright and dark areas. The contrast of this structure fades with time slowly and after 1-3 sec the background of interference fringes becomes uniform. The vertical orientation and instability of this structure suggests connection with eyelid movement and the spread of tears. If the eye is kept open for a long time, bright lines appear in the background of fringes after a dozen seconds. The slowly appearing structure might signify the tear film break-up. In case of eyes after a LASIK surgery the shape of the background structure has different nature and might be stable in time suggesting the stability of the corneal surface irregularities.

  19. Phase extraction based on iterative algorithm using five-frame crossed fringes in phase measuring deflectometry

    NASA Astrophysics Data System (ADS)

    Jin, Chengying; Li, Dahai; Kewei, E.; Li, Mengyang; Chen, Pengyu; Wang, Ruiyang; Xiong, Zhao

    2018-06-01

    In phase measuring deflectometry, two orthogonal sinusoidal fringe patterns are separately projected on the test surface and the distorted fringes reflected by the surface are recorded, each with a sequential phase shift. Then the two components of the local surface gradients are obtained by triangulation. It usually involves some complicated and time-consuming procedures (fringe projection in the orthogonal directions). In addition, the digital light devices (e.g. LCD screen and CCD camera) are not error free. There are quantization errors for each pixel of both LCD and CCD. Therefore, to avoid the complex process and improve the reliability of the phase distribution, a phase extraction algorithm with five-frame crossed fringes is presented in this paper. It is based on a least-squares iterative process. Using the proposed algorithm, phase distributions and phase shift amounts in two orthogonal directions can be simultaneously and successfully determined through an iterative procedure. Both a numerical simulation and a preliminary experiment are conducted to verify the validity and performance of this algorithm. Experimental results obtained by our method are shown, and comparisons between our experimental results and those obtained by the traditional 16-step phase-shifting algorithm and between our experimental results and those measured by the Fizeau interferometer are made.

  20. 29 CFR 1604.9 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Relating to Labor (Continued) EQUAL EMPLOYMENT OPPORTUNITY COMMISSION GUIDELINES ON DISCRIMINATION BECAUSE... discriminate between men and women with regard to fringe benefits. (c) Where an employer conditions benefits... employees and their families. Due to the fact that such conditioning discriminatorily affects the rights of...

  1. 29 CFR 1604.9 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Relating to Labor (Continued) EQUAL EMPLOYMENT OPPORTUNITY COMMISSION GUIDELINES ON DISCRIMINATION BECAUSE... discriminate between men and women with regard to fringe benefits. (c) Where an employer conditions benefits... employees and their families. Due to the fact that such conditioning discriminatorily affects the rights of...

  2. 29 CFR 1604.9 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Relating to Labor (Continued) EQUAL EMPLOYMENT OPPORTUNITY COMMISSION GUIDELINES ON DISCRIMINATION BECAUSE... discriminate between men and women with regard to fringe benefits. (c) Where an employer conditions benefits... employees and their families. Due to the fact that such conditioning discriminatorily affects the rights of...

  3. 29 CFR 1604.9 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Relating to Labor (Continued) EQUAL EMPLOYMENT OPPORTUNITY COMMISSION GUIDELINES ON DISCRIMINATION BECAUSE... discriminate between men and women with regard to fringe benefits. (c) Where an employer conditions benefits... employees and their families. Due to the fact that such conditioning discriminatorily affects the rights of...

  4. 28 CFR 54.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex...) Prohibitions. A recipient shall not: (1) Discriminate on the basis of sex with regard to making fringe benefits...

  5. 29 CFR 4.52 - Fringe benefit determinations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Office of the Secretary of Labor LABOR STANDARDS FOR FEDERAL SERVICE CONTRACTS Wage Determination Procedures § 4.52 Fringe benefit determinations. (a) Wage determinations issued pursuant to the Service Contract Act ordinarily contain provisions for vacation and holiday benefits prevailing in the locality. In...

  6. 42 CFR 432.55 - Reporting training and administrative costs.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... training (with no assigned agency duties): Salaries, fringe benefits, dependency allowances, travel, tuition, books, and educational supplies. (2) For part-time training: Travel, per diem, tuition, books and... supporting staff) assigned fulltime training functions: Salaries, fringe benefits, travel, and per diem...

  7. 45 CFR 618.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false Fringe benefits. 618.525 Section 618.525 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION NONDISCRIMINATION...: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  8. Correlation between optical return loss and transmission fringe noise in high-index contrast waveguides

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

    Xiong, Chi; Martin, Yves; Khater, Marwan

    2017-05-15

    We present a phenomenological model correlating optical return loss and amplitude of fringes in transmission spectrum due to distributed backscattering in high-index-contrast waveguides. The model is validated experimentally using four different waveguide cross sections.

  9. 45 CFR 618.525 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 3 2011-10-01 2011-10-01 false Fringe benefits. 618.525 Section 618.525 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION NONDISCRIMINATION...: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  10. 45 CFR 618.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 3 2013-10-01 2013-10-01 false Fringe benefits. 618.525 Section 618.525 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION NONDISCRIMINATION...: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  11. 45 CFR 618.525 - Fringe benefits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 3 2012-10-01 2012-10-01 false Fringe benefits. 618.525 Section 618.525 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION NONDISCRIMINATION...: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  12. 45 CFR 618.525 - Fringe benefits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 3 2014-10-01 2014-10-01 false Fringe benefits. 618.525 Section 618.525 Public Welfare Regulations Relating to Public Welfare (Continued) NATIONAL SCIENCE FOUNDATION NONDISCRIMINATION...: Any medical, hospital, accident, life insurance, or retirement benefit, service, policy or plan, any...

  13. Theoretical fringe profiles with crossed Babinet compensators in testing concave aspheric surfaces.

    PubMed

    Saxena, A K; Lancelot, J P

    1982-11-15

    This paper presents the theory for the use of crossed Babinet compensators in testing concave aspheric surfaces. Theoretical fringe profiles for a sphere and for an aspheric surface with primary aberration are shown. Advantages of this method are discussed.

  14. 42 CFR 432.55 - Reporting training and administrative costs.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) For field instruction in Medicaid: Instructors' salaries and fringe benefits, rental of space, travel... training (with no assigned agency duties): Salaries, fringe benefits, dependency allowances, travel, tuition, books, and educational supplies. (2) For part-time training: Travel, per diem, tuition, books and...

  15. 42 CFR 432.55 - Reporting training and administrative costs.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) For field instruction in Medicaid: Instructors' salaries and fringe benefits, rental of space, travel... training (with no assigned agency duties): Salaries, fringe benefits, dependency allowances, travel, tuition, books, and educational supplies. (2) For part-time training: Travel, per diem, tuition, books and...

  16. 42 CFR 432.55 - Reporting training and administrative costs.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...) For field instruction in Medicaid: Instructors' salaries and fringe benefits, rental of space, travel... training (with no assigned agency duties): Salaries, fringe benefits, dependency allowances, travel, tuition, books, and educational supplies. (2) For part-time training: Travel, per diem, tuition, books and...

  17. The self-calibration method for multiple systems at the CHARA Array

    NASA Astrophysics Data System (ADS)

    O'Brien, David

    The self-calibration method, a new interferometric technique at the CHARA Array, has been used to derive orbits for several spectroscopic binaries. This method uses the wide component of a hierarchical triple system to calibrate visibility measurements of the triple's close binary system. At certain baselines and separations, the calibrator in one of these systems can be observed quasi-simultaneously with the target. Depending on the orientation of the CHARA observation baseline relative to the orientation of the wide orbit of the triple system, separated fringe packets may be observed. A sophisticated observing scheme must be put in place to ensure the existence of separated fringe packets on nights of observation. Prior to the onset of this project, the reduction of separated fringe packet data had never included the goal of deriving visibilities for both fringe packets, so new data reduction software has been written. Visibilities obtained with separated fringe packet data for the target close binary are run through both Monte Carlo simulations and grid search programs in order to determine the best-fit orbital elements of the close binary. Several targets have been observed in this fashion, and orbits have been derived for seven targets, including three new orbits. Derivation of the orbit of the close pair in a triple system allows for the calculation of the mutual inclination, which is the angle between the planes of the wide and close orbit. Knowledge of this quantity may give insight into the formation processes that create multiple star systems. INDEX WORDS: Long-baseline interferometry, Self calibration, Separated fringe packets, Triple systems, Close binaries, Multiple systems, Orbital parameters, Near-infrared interferometry

  18. An Extrinsic Fabry-Perot Interferometric Sensor using Intermodal Phase Shifting and Demultiplexing of the Propagating Modes in a Few-Mode Fiber

    NASA Astrophysics Data System (ADS)

    Chatterjee, Julius

    This dissertation demonstrates a fiber-optic phase shifted Fabry-Perot interferometer (PS-FPI) as a sensor using modal demultiplexing. Single wavelength Fabry-Perot interferometers suffer from fringe ambiguity and loss of sensitivity at fringe extremes. These hindrances cause it to be a secondary choice when being selected for a measurement task at hand, and more often than not, white light based sensors are selected in favor of the single wavelength Fabry-Perot sensors. This work aims to introduce a technique involving the demultiplexing of the propagating linearly polarized (LP) modes in few mode fibers to obtain two fringe systems from the same sensing cavity. This results in a few-mode interferometer that effectively has two to three orders of magnitude higher perturbation sensitivity than a conventional few mode interferometer for the same sensing region. In this work, two different modal demultiplexing techniques (MD) are used to demodulate the propagating modes and to obtain two fringe sets. These output fringe sets are shifted in phase with respect to each other by a phase shift due to the propagation of the modes in the fiber-optic layout. A method of controlling this phase shift by straining a length of a two mode fiber located separate from the PS-FPI cavity is demonstrated and corresponding changes in phase shifts are shown. The results show a controllable phase shift for both the MD techniques, which is useful in sensing by permitting quadrature demodulation of interferometric fringes and also results in a novel few-mode sensing system having more than two orders of magnitude sensitivity than conventional few-mode devices.

  19. Do Penaeid Shrimps have a Preference for Mangrove Habitats? Distribution Pattern Analysis on Inhaca Island, Mozambique

    NASA Astrophysics Data System (ADS)

    Rönnbäck, P.; Macia, A.; Almqvist, G.; Schultz, L.; Troell, M.

    2002-09-01

    Scientific information on how penaeid shrimps are distributed within mangrove ecosystems is scarce, which presents an obstacle for fisheries as well as mangrove management. This study investigated the prime nursery microhabitats for the two major commercial species in Mozambique-Penaeus indicus and Metapenaeus monoceros. Stake net enclosures were used to sample shrimps living among unvegetated shallows and mangroves at Inhaca Island, Mozambique, during three consecutive spring tide periods. Four microhabitats were sampled: (1) sand flat; (2) fringe Avicennia marina on sandy substrate; (3) fringe A. marina on muddy substrate; and (4) interior A. marina adjacent to the supratidal terrestrial margin. P. indicus had a significant preference for fringe mangroves over the adjacent sand flat (P<0·001 and P=0·05). Postlarval shrimps only occupied the sand flat, whereas the mangrove was utilized by postlarval, juvenile and sub-adult life stages. Within the fringe mangrove, there was no correlation between shrimp abundance and organic content of sediment (5·7-11·6 shrimps m-2). Shrimps utilized the most interior margin of the mangroves (0·35 shrimps m-2), although catch rates were significantly lower than in the mangrove fringe (P<0·001). M. monoceros was significantly (P<0·01), more abundant in the sand flat (0·44-2·1 shrimps m-2) than in the mangrove fringe (0·04-0·61 shrimps m-2), although this habitat preference was not evident for juvenile and sub-adult life stages. The results demonstrate the extensive use of mangrove habitats by penaeid shrimps. The confinement to mangroves for P. indicus, but not for M. monoceros, is discussed in the context of habitat characteristics and predation avoidance behaviour. Methodological considerations of the stake net technique are also outlined.

  20. Phase retrieval from the phase-shift moiré fringe patterns in simultaneous dual-wavelength interferometry

    NASA Astrophysics Data System (ADS)

    Cheng, Jinlong; Gao, Zhishan; Bie, Shuyou; Dou, Yimeng; Ni, Ruihu; Yuan, Qun

    2018-02-01

    Simultaneous dual-wavelength interferometry (SDWI) could extend the measured range of each single-wavelength interferometry. The moiré fringe generated in SDWI indirectly represents the information of the measured long synthetic-wavelength ({λ }{{S}}) phase, thus the phase demodulation is rather arduous. To address this issue, we present a method to convert the moiré fringe pattern into a synthetic-wavelength interferogram (moiré to synthetic-wavelength, MTS). After the square of the moiré fringe pattern in the MTS method, the additive moiré pattern is turned into a multiplicative one. And the synthetic-wavelength interferogram could be obtained by a low-pass filtering in spectrum of the multiplicative moiré fringe pattern. Therefore, when the dual-wavelength interferometer is implemented with the π/2 phase shift at {λ }{{S}}, a sequence of synthetic-wavelength phase-shift interferograms with π/2 phase shift could be obtained after the MTS method processing on the captured moiré fringe patterns. And then the synthetic-wavelength phase could be retrieved by the conventional phase-shift algorithm. Compared with other methods in SDWI, the proposed MTS approach could reduce the restriction of the phase shift and frame numbers for the adoption of the conventional phase-shift algorithm. Following, numerical simulations are executed to evaluate the performance of the MTS method in processing time, frames of interferograms and the phase shift error compensation. And the necessary linear carrier for MTS method is less than 0.11 times of the traditional dual-wavelength spatial-domain Fourier transform method. Finally, the deviations for MTS method in experiment are 0.97% for a step with the height of 7.8 μm and 1.11% for a Fresnel lens with the step height of 6.2328 μm.

  1. 40 CFR 5.525 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex...) Prohibitions. A recipient shall not: (1) Discriminate on the basis of sex with regard to making fringe benefits...

  2. 49 CFR 25.525 - Fringe benefits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Transportation Office of the Secretary of Transportation NONDISCRIMINATION ON THE BASIS OF SEX IN EDUCATION PROGRAMS OR ACTIVITIES RECEIVING FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in...) Prohibitions. A recipient shall not: (1) Discriminate on the basis of sex with regard to making fringe benefits...

  3. 26 CFR 1.61-21 - Taxation of fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... of the chauffeur's services (including any special qualifications of the chauffeur (e.g., training in....61-21 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX... includes compensation for services, including fees, commissions, fringe benefits, and similar items. For an...

  4. Measurement of gradient index profiles by Babinet fringe analysis.

    PubMed

    Pandya, T P; Saxena, A K

    1979-03-01

    A theory for determining one-dimensional ray deflections with the help of distorted Babinet fringes has been developed. An approach for investigating two-dimensional ray deflections has been presented. Applications of the techniques for the study of gradient index glass have been described.

  5. Three-dimensional motion detection of a 20-nm gold nanoparticle using twilight-field digital holography with coherence regulation.

    PubMed

    Goto, Kazufumi; Hayasaki, Yoshio

    2015-07-15

    In the twilight-field method for obtaining interference fringes with high contrast in in-line digital holography, only the intensity of the reference light is regulated to be close to the intensity of the object light, which is the ultra-weak scattered light from a nanoparticle, by using a low-frequency attenuation filter. Coherence of the light also strongly affects the contrast of the interference fringes. High coherence causes a lot of undesired coherent noise, which masks the fringes derived from the nanoparticles. Too-low coherence results in fringes with low contrast and a correspondingly low signal-to-noise ratio. Consequently, proper regulation of the coherence of the light source, in this study the spectral width, improves the minimum detectable size in holographic three-dimensional position measurement of nanoparticles. By using these methods, we were able to measure the position of a gold nanoparticle with a minimum diameter of 20 nm.

  6. Four-quadrant gratings moiré fringe alignment measurement in proximity lithography.

    PubMed

    Zhu, Jiangping; Hu, Song; Yu, Junsheng; Zhou, Shaolin; Tang, Yan; Zhong, Min; Zhao, Lixin; Chen, Minyong; Li, Lanlan; He, Yu; Jiang, Wei

    2013-02-11

    This paper aims to deal with a four-quadrant gratings alignment method benefiting from phase demodulation for proximity lithography, which combines the advantages of interferometry with image processing. Both the mask alignment mark and the wafer alignment mark consist of four sets of gratings, which bring the convenience and simplification of realization for coarse alignment and fine alignment. Four sets of moiré fringes created by superposing the mask alignment mark and the wafer alignment mark are highly sensitive to the misalignment between them. And the misalignment can be easily determined through demodulating the phase of moiré fringe without any external reference. Especially, the period and phase distribution of moiré fringes are unaffected by the gap between the mask and the wafer, not excepting the wavelength of alignment illumination. Disturbance from the illumination can also be negligible, which enhances the technological adaptability. The experimental results bear out the feasibility and rationality of our designed approach.

  7. Fiber-optic projected-fringe digital interferometry

    NASA Technical Reports Server (NTRS)

    Mercer, Carolyn R.; Beheim, Glenn

    1990-01-01

    A phase-stepped projected-fringe interferometer was developed which uses a closed-loop fiber-optic phase-control system to make very accurate surface profile measurements. The closed-loop phase-control system greatly reduces phase-stepping error, which is frequently the dominant source of error in digital interferometers. Two beams emitted from a fiber-optic coupler are combined to form an interference fringe pattern on a diffusely reflecting object. Reflections off of the fibers' output faces are used to create a phase-indicating signal for the closed-loop optical phase controller. The controller steps the phase difference between the two beams by pi/2 radians in order to determine the object's surface profile using a solid-state camera and a computer. The system combines the ease of alignment and automated data reduction of phase-stepping projected-fringe interferometry with the greatly improved phase-stepping accuracy of our closed-loop phase-controller. The system is demonstrated by measuring the profile of a plate containing several convex surfaces whose heights range from 15 to 25 micron high.

  8. Temperature dependence of the coherence in polariton condensates

    NASA Astrophysics Data System (ADS)

    Rozas, E.; Martín, M. D.; Tejedor, C.; Viña, L.; Deligeorgis, G.; Hatzopoulos, Z.; Savvidis, P. G.

    2018-02-01

    We present a time-resolved experimental study of the temperature effect on the coherence of traveling polariton condensates. The simultaneous detection of their emission both in real and reciprocal space allows us to fully monitor the condensates' dynamics. We obtain fringes in reciprocal space as a result of the interference between polariton wave packets (WPs) traveling with the same speed. The periodicity of these fringes is inversely proportional to the spatial distance between the interfering WPs. In a similar fashion, we obtain interference fringes in real space when WPs traveling in opposite directions meet. The visibility of both real- and reciprocal-space interference fringes rapidly decreases with increasing temperature and vanishes. A theoretical description of the phase transition, considering the coexistence of condensed and noncondensed particles, for an out-of-equilibrium condensate such as ours is still missing, yet a comparison with theories developed for atomic condensates allows us to infer a critical temperature for the BEC-like transition when the visibility goes to zero.

  9. Large radius of curvature measurement based on virtual quadratic Newton rings phase-shifting moiré-fringes measurement method in a nonnull interferometer.

    PubMed

    Yang, Zhongming; Wang, Kailiang; Cheng, Jinlong; Gao, Zhishan; Yuan, Qun

    2016-06-10

    We have proposed a virtual quadratic Newton rings phase-shifting moiré-fringes measurement method in a nonnull interferometer to measure the large radius of curvature for a spherical surface. In a quadratic polar coordinate system, linear carrier testing Newton rings interferogram and virtual Newton rings interferogram form the moiré fringes. It is possible to retrieve the wavefront difference data between the testing and standard spherical surface from the moiré fringes after low-pass filtering. Based on the wavefront difference data, we deduced a precise formula to calculate the radius of curvature in the quadratic polar coordinate system. We calculated the retrace error in the nonnull interferometer using the multi-configuration model of the nonnull interferometric system in ZEMAX. Our experimental results indicate that the measurement accuracy is better than 0.18% for a spherical mirror with a radius of curvature of 41,400 mm.

  10. Theoretical study of the properties of X-ray diffraction moiré fringes. I

    PubMed Central

    Yoshimura, Jun-ichi

    2015-01-01

    A detailed and comprehensive theoretical description of X-ray diffraction moiré fringes for a bicrystal specimen is given on the basis of a calculation by plane-wave dynamical diffraction theory. Firstly, prior to discussing the main subject of the paper, a previous article [Yoshimura (1997 ▸). Acta Cryst. A53, 810–812] on the two-dimensionality of diffraction moiré patterns is restated on a thorough calculation of the moiré interference phase. Then, the properties of moiré fringes derived from the above theory are explained for the case of a plane-wave diffraction image, where the significant effect of Pendellösung intensity oscillation on the moiré pattern when the crystal is strained is described in detail with theoretically simulated moiré images. Although such plane-wave moiré images are not widely observed in a nearly pure form, knowledge of their properties is essential for the understanding of diffraction moiré fringes in general. PMID:25970298

  11. Single and two-shot quantitative phase imaging using Hilbert-Huang Transform based fringe pattern analysis

    NASA Astrophysics Data System (ADS)

    Trusiak, Maciej; Micó, Vicente; Patorski, Krzysztof; García-Monreal, Javier; Sluzewski, Lukasz; Ferreira, Carlos

    2016-08-01

    In this contribution we propose two Hilbert-Huang Transform based algorithms for fast and accurate single-shot and two-shot quantitative phase imaging applicable in both on-axis and off-axis configurations. In the first scheme a single fringe pattern containing information about biological phase-sample under study is adaptively pre-filtered using empirical mode decomposition based approach. Further it is phase demodulated by the Hilbert Spiral Transform aided by the Principal Component Analysis for the local fringe orientation estimation. Orientation calculation enables closed fringes efficient analysis and can be avoided using arbitrary phase-shifted two-shot Gram-Schmidt Orthonormalization scheme aided by Hilbert-Huang Transform pre-filtering. This two-shot approach is a trade-off between single-frame and temporal phase shifting demodulation. Robustness of the proposed techniques is corroborated using experimental digital holographic microscopy studies of polystyrene micro-beads and red blood cells. Both algorithms compare favorably with the temporal phase shifting scheme which is used as a reference method.

  12. Communication: Development of standing evanescent-wave fluorescence correlation spectroscopy and its application to the lateral diffusion of lipids in a supported lipid bilayer

    NASA Astrophysics Data System (ADS)

    Otosu, Takuhiro; Yamaguchi, Shoichi

    2017-07-01

    We present standing evanescent-wave fluorescence correlation spectroscopy (SEW-FCS). This technique utilizes the interference of two evanescent waves which generates a standing evanescent-wave. Fringe-pattern illumination created by a standing evanescent-wave enables us to measure the diffusion coefficients of molecules with a super-resolution corresponding to one fringe width. Because the fringe width can be reliably estimated by a simple procedure, utilization of fringes is beneficial to quantitatively analyze the slow diffusion of molecules in a supported lipid bilayer (SLB), a model biomembrane formed on a solid substrate, with the timescale relevant for reliable FCS analysis. Furthermore, comparison of the data between SEW-FCS and conventional total-internal reflection FCS, which can also be performed by the SEW-FCS instrument, effectively eliminates the artifact due to afterpulsing of the photodiode detector. The versatility of SEW-FCS is demonstrated by its application to various SLBs.

  13. Phase compensation with fiber optic surface profile acquisition and reconstruction system

    NASA Astrophysics Data System (ADS)

    Bo, En; Duan, Fajie; Feng, Fan; Lv, Changrong; Xiao, Fu; Huang, Tingting

    2015-02-01

    A fiber-optic sinusoidal phase modulating (SPM) interferometer was proposed for the acquisition and reconstruction of three-dimensional (3-D) surface profile. Sinusoidal phase modulation was induced by controlling the injection current of light source. The surface profile was constructed on the basis of fringe projection. Fringe patterns are vulnerable to external disturbances such as mechanical vibration and temperature fluctuation, which cause phase drift in the interference signal and decrease measuring accuracy. A closed-loop feedback phase compensation system was built. In the subsystem, the initial phase of the interference signal, which was caused by the initial optical path difference between interference arms, could be demodulated using phase generated carrier (PGC) method and counted out using coordinated rotation digital computer (CORDIC) , then a compensation voltage was generated for the PZT driver. The bias value of external disturbances superimposed on fringe patterns could be reduced to about 50 mrad, and the phase stability for interference fringes was less than 6 mrad. The feasibility for real-time profile measurement has been verified.

  14. Topometry of technical and biological objects by fringe projection

    NASA Astrophysics Data System (ADS)

    Windecker, R.; Tiziani, H. J.

    1995-07-01

    Fringe projection is a fast and accurate technique for obtaining the topometry of a wide range of surfaces. Here some features of the principle are described, together with the possibilities of adapting this technique for the measurement of vaulted surfaces. We discuss various methods of phase evaluation and compare them with simulated computer data to obtain the resolution limits. Under certain restrictions a semispatial algorithm, called the modified Fourier analysis algorithm, gives the best results. One special subject of interest is the application of fringe projection for the measurement of the three-dimensional surface of the cornea. First results of in vivo measurements are presented.

  15. Interferometric angle monitor

    NASA Technical Reports Server (NTRS)

    Minott, P. O. (Inventor)

    1983-01-01

    Two mutually coherent light beams formed from a single monochromatic light source were directed to a reflecting surface of a rotatable object. They were reflected into an imaging optical lens having a focal plane optically at infinity. A series of interference fringes were formed in the focal plane which were translated linearly in response to angular rotation of the object. Photodetectors were located adjacent the focal plane to detect the fringe translation and output a signal in response to the translation. The signal was fed to a signal processor which was adapted to count the number of fringes detected and develop a measure of the angular rotation and direction of the object.

  16. A bi-prism interferometer for hard x-ray photons

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

    Isakovic, A.F.; Siddons, D.; Stein, A.

    2010-04-06

    Micro-fabricated bi-prisms have been used to create an interference pattern from an incident hard X-ray beam, and the intensity of the pattern probed with fluorescence from a 30 nm-thick metal film. Maximum fringe visibility exceeded 0.9 owing to the nano-sized probe and the choice of single-crystal prism material. A full near-field analysis is necessary to describe the fringe field intensities, and the transverse coherence lengths were extracted at APS beamline 8-ID-I. It is also shown that the maximum number of fringes is dependent only on the complex refractive index of the prism material.

  17. Complementarity and Young's interference fringes from two atoms

    NASA Astrophysics Data System (ADS)

    Itano, W. M.; Bergquist, J. C.; Bollinger, J. J.; Wineland, D. J.; Eichmann, U.; Raizen, M. G.

    1998-06-01

    The interference pattern of the resonance fluorescence from a J=1/2 to J=1/2 transition of two identical atoms confined in a three-dimensional harmonic potential is calculated. The thermal motion of the atoms is included. Agreement is obtained with experiments [U. Eichmann et al., Phys. Rev. Lett. 70, 2359 (1993)]. Contrary to some theoretical predictions, but in agreement with the present calculations, a fringe visibility greater than 50% can be observed with polarization-selective detection. The dependence of the fringe visibility on polarization has a simple interpretation, based on whether or not it is possible in principle to determine which atom emitted the photon.

  18. Demodulation of moire fringes in digital holographic interferometry using an extended Kalman filter.

    PubMed

    Ramaiah, Jagadesh; Rastogi, Pramod; Rajshekhar, Gannavarpu

    2018-03-10

    This paper presents a method for extracting multiple phases from a single moire fringe pattern in digital holographic interferometry. The method relies on component separation using singular value decomposition and an extended Kalman filter for demodulating the moire fringes. The Kalman filter is applied by modeling the interference field locally as a multi-component polynomial phase signal and extracting the associated multiple polynomial coefficients using the state space approach. In addition to phase, the corresponding multiple phase derivatives can be simultaneously extracted using the proposed method. The applicability of the proposed method is demonstrated using simulation and experimental results.

  19. Second harmonic generation: Effects of the multiple reflections of the fundamental and the second harmonic waves on the Maker fringes

    NASA Astrophysics Data System (ADS)

    Tellier, Gildas; Boisrobert, Christian

    2007-11-01

    The Maker fringes technique is commonly used for the determination of nonlinear optical coefficients. In this article, we present a new formulation of Maker fringes in parallel-surface samples, using boundary conditions taking into account the anisotropy of the crystal, the refractive-index dispersion, and the reflections of the fundamental and the second harmonic waves inside the material. Complete expressions for the generated second harmonic intensity are given for birefringent crystals for the case of no pump depletion. A comparison between theory and experimental results is made, showing the accuracy of our theoretical expressions.

  20. Fused off-axis object illumination direct-to-digital holography with a plurality of illumination sources

    DOEpatents

    Price, Jeffery R.; Bingham, Philip R.

    2005-11-08

    Systems and methods are described for rapid acquisition of fused off-axis illumination direct-to-digital holography. A method of recording a plurality of off-axis object illuminated spatially heterodyne holograms, each of the off-axis object illuminated spatially heterodyne holograms including spatially heterodyne fringes for Fourier analysis, includes digitally recording, with a first illumination source of an interferometer, a first off-axis object illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis; and digitally recording, with a second illumination source of the interferometer, a second off-axis object illuminated spatially heterodyne hologram including spatially heterodyne fringes for Fourier analysis.

  1. Model-based multi-fringe interferometry using Zernike polynomials

    NASA Astrophysics Data System (ADS)

    Gu, Wei; Song, Weihong; Wu, Gaofeng; Quan, Haiyang; Wu, Yongqian; Zhao, Wenchuan

    2018-06-01

    In this paper, a general phase retrieval method is proposed, which is based on one single interferogram with a small amount of fringes (either tilt or power). Zernike polynomials are used to characterize the phase to be measured; the phase distribution is reconstructed by a non-linear least squares method. Experiments show that the proposed method can obtain satisfactory results compared to the standard phase-shifting interferometry technique. Additionally, the retrace errors of proposed method can be neglected because of the few fringes; it does not need any auxiliary phase shifting facilities (low cost) and it is easy to implement without the process of phase unwrapping.

  2. Fourier fringe analysis and its application to metrology of extreme physical phenomena: a review [Invited].

    PubMed

    Takeda, Mitsuo

    2013-01-01

    The paper reviews a technique for fringe analysis referred to as Fourier fringe analysis (FFA) or the Fourier transform method, with a particular focus on its application to metrology of extreme physical phenomena. Examples include the measurement of extremely small magnetic fields with subfluxon sensitivity by electron wave interferometry, subnanometer wavefront evaluation of projection optics for extreme UV lithography, the detection of sub-Ångstrom distortion of a crystal lattice, and the measurement of ultrashort optical pulses in the femotsecond to attosecond range, which show how the advantages of FFA are exploited in these cutting edge applications.

  3. Solenoid Fringe Field Effects for the Neutrino Factory Linac - MAD-X Investigation

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

    M. Aslaninejad,C. Bontoiu,J. Pasternak,J. Pozimski,Alex Bogacz

    2010-05-01

    International Design Study for the Neutrino Factory (IDS-NF) assumes the first stage of muon acceleration (up to 900 MeV) to be implemented with a solenoid based Linac. The Linac consists of three styles of cryo-modules, containing focusing solenoids and varying number of SRF cavities for acceleration. Fringe fields of the solenoids and the focusing effects in the SRF cavities have significant impact on the transverse beam dynamics. Using an analytical formula, the effects of fringe fields are studied in MAD-X. The resulting betatron functions are compared with the results of beam dynamics simulations using OptiM code.

  4. Electro-optic fringe locking and photometric tuning using a two-stage Mach-Zehnder lithium niobate waveguide for high-contrast mid-infrared interferometry

    NASA Astrophysics Data System (ADS)

    Martin, Guillermo; Heidmann, Samuel; Rauch, Jean-Yves; Jocou, Laurent; Courjal, Nadège

    2014-03-01

    We present an optimization process to improve the rejection ratio in integrated beam combiners by locking the dark fringe and then monitoring its intensity. The method proposed here uses the electro-optic effect of lithium niobate in order to lock the dark fringe and to real-time balance the photometric flux by means of a two-stage Mach-Zehnder interferometer waveguide. By applying a control voltage on the output Y-junction, we are able to lock the phase and stay in the dark fringe, while an independent second voltage is applied on the first-stage intensity modulator, to finely balance the photometries. We have obtained a rejection ratio of 4600 (36.6 dB) at 3.39 μm in transverse electric polarization, corresponding to 99.98% fringe contrast, and shown that the system can compensate external phase perturbations (a piston variation of 100 nm) up to around 1 kHz. We also show the preliminary results of this process on wide-band modulation, where a contrast of 38% in 3.25- to 3.65-μm spectral range is obtained. These preliminary results on wide-band need to be optimized, in particular, for reducing scattered light of the device at the Y-junction. We expect this active method to be useful in high-contrast interferometry, in particular, for astronomical spatial projects actually under study.

  5. Motion-oriented high speed 3-D measurements by binocular fringe projection using binary aperiodic patterns.

    PubMed

    Feng, Shijie; Chen, Qian; Zuo, Chao; Tao, Tianyang; Hu, Yan; Asundi, Anand

    2017-01-23

    Fringe projection is an extensively used technique for high speed three-dimensional (3-D) measurements of dynamic objects. To precisely retrieve a moving object at pixel level, researchers prefer to project a sequence of fringe images onto its surface. However, the motion often leads to artifacts in reconstructions due to the sequential recording of the set of patterns. In order to reduce the adverse impact of the movement, we present a novel high speed 3-D scanning technique combining the fringe projection and stereo. Firstly, promising measuring speed is achieved by modifying the traditional aperiodic sinusoidal patterns so that the fringe images can be cast at kilohertz with the widely used defocusing strategy. Next, a temporal intensity tracing algorithm is developed to further alleviate the influence of motion by accurately tracing the ideal intensity for stereo matching. Then, a combined cost measure is suggested to robustly estimate the cost for each pixel and lastly a three-step framework of refinement follows not only to eliminate outliers caused by the motion but also to obtain sub-pixel disparity results for 3-D reconstructions. In comparison with the traditional method where the effect of motion is not considered, experimental results show that the reconstruction accuracy for dynamic objects can be improved by an order of magnitude with the proposed method.

  6. Punching loan sharks on the nose: effective interventions to reduce financial hardship in New Zealand.

    PubMed

    Signal, Louise; Lanumata, Tolotea; Bowers, Sharron

    2012-08-01

    Growth in the high-cost, unregulated fringe lender market (with these lenders commonly referred to as loan sharks) has occurred both internationally and in New Zealand in recent years. The credit practices of loan sharks create financial hardship for many people including Māori, Pacific and low-income New Zealanders. This paper reports on research that explored strategies for reducing the impact of the fringe lender market on Māori, Pacific and low-income New Zealanders. A narrative literature review and 10 key informant interviews were conducted to provide information on how best to intervene to reduce the impact of the fringe lender market for these people. The main interventions identified were: two regulatory approaches, one for capping interest rates and another to create codes of responsible lending; access to safe affordable micro-finance options; financial literacy education; and Pacific cultural change around fa'alavelave, which are the 'obligations' of giving. Protecting consumers from the unsafe practices of fringe lenders requires a combined approach of discouraging the undesirable practices of fringe lenders through regulation and encouraging the growth of safe, affordable micro-finance options. Financial literacy education is a valuable activity for directing consumer attention to the safest options, but in isolation will have limited effect if options are limited. Health promoters have a valuable role to play in implementing these interventions.

  7. Surface flatness measurement of quasi-parallel plates employing three-beam interference with strong reference beam

    NASA Astrophysics Data System (ADS)

    Sunderland, Zofia; Patorski, Krzysztof

    2016-12-01

    A big challenge for standard interferogram analysis methods such as Temporal Phase Shifting or Fourier Transform is a parasitic set of fringes which might occur in the analyzed fringe pattern intensity distribution. It is encountered, for example, when transparent glass plates with quasi-parallel surfaces are tested in Fizeau or Twyman-Green interferometers. Besides the beams reflected from the plate front surface and the interferometer reference the beam reflected from the plate rear surface also plays important role; its amplitude is comparable with the amplitude of other beams. In result we face three families of fringes of high contrast which cannot be easily separated. Earlier we proposed a competitive solution for flatness measurements which relies on eliminating one of those fringe sets from the three-beam interferogram and separating two remaining ones with the use of 2D Continuous Wavelet Transform. In this work we cover the case when the intensity of the reference beam is significantly higher than the intensities of two object beams. The main advantage of differentiating beam intensities is the change in contrast of individual fringe families. Processing of such three-beam interferograms is modified but also takes advantage of 2D CWT. We show how to implement this method in Twyman-Green and Fizeau setups and compare this processing path and measurement procedures with previously proposed solutions.

  8. 29 CFR 4.165 - Wage payments and fringe benefits-in general.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... and regularly recurring workweek of seven consecutive 24-hour workday periods, and the records must be... 4.165 Labor Office of the Secretary of Labor LABOR STANDARDS FOR FEDERAL SERVICE CONTRACTS... fringe benefits (see § 4.177). (2) The Act makes no distinction, with respect to its compensation...

  9. 20 CFR 641.850 - Are there other specific allowable and unallowable cost requirements for the SCSEP?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... unallowable cost requirements for the SCSEP? 641.850 Section 641.850 Employees' Benefits EMPLOYMENT AND...) Participants' fringe benefit costs. Recipients and subrecipients may use SCSEP funds for participant fringe benefit costs only under the conditions set forth in § 641.565. ...

  10. 42 CFR 493.649 - Methodology for determining fee amount.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... fringe benefit costs to support the required number of State inspectors, management and direct support... full time equivalent employee. Included in this cost are salary and fringe benefit costs, necessary... 42 Public Health 5 2010-10-01 2010-10-01 false Methodology for determining fee amount. 493.649...

  11. Double-Glazing Interferometry

    ERIC Educational Resources Information Center

    Toal, Vincent; Mihaylova, Emilia M.

    2009-01-01

    This note describes how white light interference fringes can be seen by observing the Moon through a double-glazed window. White light interferometric fringes are normally observed only in a well-aligned interferometer whose optical path difference is less than the coherence length of the light source, which is approximately one micrometer for…

  12. Contaminant profiles for surface water, sediment, flora and fauna associated with the mangrove fringe along middle and lower East Tampa Bay

    EPA Science Inventory

    Contaminant concentrations are reported for surface water, sediment, seagrass, mangroves, Florida Crown conch, blue crabs and fish collected during 2010-2011 from the mangrove fringe along eastern Tampa Bay. Concentrations of trace metals, chlorinated pesticides, atrazine, total ...

  13. 7 CFR 15a.56 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false Fringe benefits. 15a.56 Section 15a.56 Agriculture Office of the Secretary of Agriculture EDUCATION PROGRAMS OR ACTIVITIES RECEIVING OR BENEFITTING FROM FEDERAL FINANCIAL ASSISTANCE Discrimination on the Basis of Sex in Employment in Education Programs and...

  14. 78 FR 73451 - Defense Federal Acquisition Regulation Supplement: Unallowable Fringe Benefit Costs (DFARS Case...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-06

    ... internal controls to eliminate costs that are already unallowable. 2. Broadening the Category of Fringe... recent problems. Reasonable internal controls can significantly reduce the amount of ineligible dependent... effect of the rule is to make the DFARS consistent with current commercial practice. 8. Internal Controls...

  15. Subtropical Biotic Fringing Reefs as Ecological Laboratories.

    ERIC Educational Resources Information Center

    Hunt, Jeffrey W.

    1980-01-01

    Describes a 16-week course in marine biology involving a class-coordinated investigation of a subtropical biotic fringing reef of Hawaii. Describes in detail the development of preliminary hypotheses regarding general cause-effect relationships on the reef, and the exploration of specific areas, such as chemical or physical factors. (CS)

  16. 29 CFR 1620.11 - Fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... benefits. Differences in the application of fringe benefit plans which are based upon sex-based actuarial studies cannot be justified as based on “any other factor other than sex.” (c) Where an employer... spouses or families of employees of one gender where the same benefits are not made available for the...

  17. 29 CFR 1620.11 - Fringe benefits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... benefits. Differences in the application of fringe benefit plans which are based upon sex-based actuarial studies cannot be justified as based on “any other factor other than sex.” (c) Where an employer... spouses or families of employees of one gender where the same benefits are not made available for the...

  18. 29 CFR 4.171 - “Bona fide” fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... compensation, workers' compensation, or social security, is a fringe benefit for purposes of the Act. (d) The... expenses incident to employment, incentive or suggestion awards, and recruitment bonuses, as well as tools...) Contributions by contractors for such items as social functions or parties for employees, flowers, cards, or...

  19. Characteristics of fringed myotis day roosts in northern California

    Treesearch

    Theodore L. Weller; Cynthia J. Zabel

    2001-01-01

    Understanding habitat relationships; of forest dwelling bats has become a wildlife management priority during the past decade. We used radiotelemetry to examine the use of day roosts by fringed myotis (Myotis thysanodes) in a Douglas-fir (Pseudotsuga menziesii) forest in northern California. We located 52 roosts in 23 trees and...

  20. Broadband interferometric characterization of divergence and spatial chirp.

    PubMed

    Meier, Amanda K; Iliev, Marin; Squier, Jeff A; Durfee, Charles G

    2015-09-01

    We demonstrate a spectral interferometric method to characterize lateral and angular spatial chirp to optimize intensity localization in spatio-temporally focused ultrafast beams. Interference between two spatially sheared beams in an interferometer will lead to straight fringes if the wavefronts are curved. To produce reference fringes, we delay one arm relative to another in order to measure fringe rotation in the spatially resolved spectral interferogram. With Fourier analysis, we can obtain frequency-resolved divergence. In another arrangement, we spatially flip one beam relative to the other, which allows the frequency-dependent beamlet direction (angular spatial chirp) to be measured. Blocking one beam shows the spatial variation of the beamlet position with frequency (i.e., the lateral spatial chirp).

  1. Fringe localization requirements for three-dimensional flow visualization of shock waves in diffuse-illumination double-pulse holographic interferometry

    NASA Technical Reports Server (NTRS)

    Decker, A. J.

    1982-01-01

    A theory of fringe localization in rapid-double-exposure, diffuse-illumination holographic interferometry was developed. The theory was then applied to compare holographic measurements with laser anemometer measurements of shock locations in a transonic axial-flow compressor rotor. The computed fringe localization error was found to agree well with the measured localization error. It is shown how the view orientation and the curvature and positional variation of the strength of a shock wave are used to determine the localization error and to minimize it. In particular, it is suggested that the view direction not deviate from tangency at the shock surface by more than 30 degrees.

  2. Scattering of a Tightly Focused Beam by an Optically Trapped Particle

    NASA Technical Reports Server (NTRS)

    Lock, James A.; Wrbanek, Susan Y.; Weiland, Kenneth E.

    2006-01-01

    Near-forward scattering of an optically trapped 5 m radius polystyrene latex sphere by the trapping beam was examined both theoretically and experimentally. Since the trapping beam is tightly focused, the beam fields superpose and interfere with the scattered fields in the forward hemisphere. The observed light intensity consists of a series of concentric bright and dark fringes centered about the forward scattering direction. Both the number of fringes and their contrast depend on the position of the trapping beam focal waist with respect to the sphere. The fringes are caused by diffraction due to the truncation of the tail of the trapping beam as the beam is transmitted through the sphere.

  3. Evaporative Cooling in a Holographic Atom Trap

    NASA Technical Reports Server (NTRS)

    Newell, Raymond

    2003-01-01

    We present progress on evaporative cooling of Rb-87 atoms in our Holographic Atom Trap (HAT). The HAT is formed by the interference of five intersecting YAG laser beams: atoms are loaded from a vapor-cell MOT into the bright fringes of the interference pattern through the dipole force. The interference pattern is composed of Talbot fringes along the direction of propagation of the YAG beams, prior to evaporative cooling each Talbot fringe contains 300,000 atoms at 50 micro-K and peak densities of 2 x 10(exp 14)/cu cm. Evaporative cooling is achieved through adiabatically decreasing the intensity of the YAG laser. We present data and calculations covering a range of HAT geometries and cooling procedures.

  4. Improving Spectral Results Using Row-by-Row Fourier Transform of Spatial Heterodyne Raman Spectrometer Interferogram.

    PubMed

    Barnett, Patrick D; Strange, K Alicia; Angel, S Michael

    2017-06-01

    This work describes a method of applying the Fourier transform to the two-dimensional Fizeau fringe patterns generated by the spatial heterodyne Raman spectrometer (SHRS), a dispersive interferometer, to correct the effects of certain types of optical alignment errors. In the SHRS, certain types of optical misalignments result in wavelength-dependent and wavelength-independent rotations of the fringe pattern on the detector. We describe here a simple correction technique that can be used in post-processing, by applying the Fourier transform in a row-by-row manner. This allows the user to be more forgiving of fringe alignment and allows for a reduction in the mechanical complexity of the SHRS.

  5. Mirror-assisted coherent backscattering from the Mollow sidebands

    NASA Astrophysics Data System (ADS)

    Piovella, N.; Teixeira, R. Celistrino; Kaiser, R.; Courteille, Ph. W.; Bachelard, R.

    2017-11-01

    In front of a mirror, the radiation of weakly driven large disordered clouds presents an interference fringe in the backward direction, on top of an incoherent background. Although strongly driven atoms usually present little coherent scattering, we show here that the mirror-assisted version can produce high contrast fringes, for arbitrarily high saturation parameters. The contrast of the fringes oscillates with the Rabi frequency of the atomic transition and the distance between the mirror and the atoms, due to the coherent interference between the carrier and the Mollow sidebands of the saturated resonant fluorescence spectrum emitted by the atoms. The setup thus represents a powerful platform to study the spectral properties of ensembles of correlated scatterers.

  6. Microwave radiometric aircraft observations of the Fabry-Perot interference fringes of an ice-water system

    NASA Technical Reports Server (NTRS)

    Harrington, R. F.; Swift, C. T.; Fedors, J. C.

    1980-01-01

    Airborne stepped-frequency microwave radiometer (SFMR) observations of the Fabry-Perot interference fringes of ice-water systems are discussed. The microwave emissivity at normal incidence of a smooth layered dielectric medium over a semi-infinite dielectric medium is examined for the case of ice over water as a function of ice thickness and attenuation coefficient, and the presence of quarter-wavelength oscillations in emissivity as the ice thickness and frequency are varied is pointed out. Experimental observations of pronounced quarter-wavelength oscillations in radiometric brightness temperature due to the Fabry-Perot interference fringes over smooth sea ice and lake ice varying in roughness as the radiometer frequencies were scanned are then presented.

  7. Double-resolution electron holography with simple Fourier transform of fringe-shifted holograms.

    PubMed

    Volkov, V V; Han, M G; Zhu, Y

    2013-11-01

    We propose a fringe-shifting holographic method with an appropriate image wave recovery algorithm leading to exact solution of holographic equations. With this new method the complex object image wave recovered from holograms appears to have much less traditional artifacts caused by the autocorrelation band present practically in all Fourier transformed holograms. The new analytical solutions make possible a double-resolution electron holography free from autocorrelation band artifacts and thus push the limits for phase resolution. The new image wave recovery algorithm uses a popular Fourier solution of the side band-pass filter technique, while the fringe-shifting holographic method is simple to implement in practice. Published by Elsevier B.V.

  8. Capillary Absorption Spectrometer for 13C Isotopic Composition of Pico to Subpico Molar Sample Quantities

    NASA Astrophysics Data System (ADS)

    Moran, J.; Kelly, J.; Sams, R.; Newburn, M.; Kreuzer, H.; Alexander, M.

    2011-12-01

    Quick incorporation of IR spectroscopy based isotope measurements into cutting edge research in biogeochemical cycling attests to the advantages of a spectroscopy versus mass spectrometry method for making some 13C measurements. The simple principles of optical spectroscopy allow field portability and provide a more robust general platform for isotope measurements. We present results with a new capillary absorption spectrometer (CAS) with the capability of reducing the sample size required for high precision isotopic measurements to the picomolar level and potentially the sub-picomolar level. This work was motivated by the minute sample size requirements for laser ablation isotopic studies of carbon cycling in microbial communities but has potential to be a valuable tool in other areas of biological and geological research. The CAS instrument utilizes a capillary waveguide as a sample chamber for interrogating CO2 via near IR laser absorption spectroscopy. The capillary's small volume (~ 0.5 mL) combined with propagation and interaction of the laser mode with the entire sample reduces sample size requirements to a fraction of that accessible with commercially available IR absorption including those with multi-pass or ring-down cavity systems. Using a continuous quantum cascade laser system to probe nearly adjacent rovibrational transitions of different isotopologues of CO2 near 2307 cm-1 permits sample measurement at low analyte pressures (as low as 2 Torr) for further sensitivity improvement. A novel method to reduce cw-fringing noise in the hollow waveguide is presented, which allows weak absorbance features to be studied at the few ppm level after averaging 1,000 scans in 10 seconds. Detection limits down to the 20 picomoles have been observed, a concentration of approximately 400 ppm at 2 Torr in the waveguide with precision and accuracy at or better than 1 %. Improvements in detection and signal averaging electronics and laser power and mode quality are anticipated to reduce the required samples size to a 100-200 femtomoles of carbon. We report the application of the CAS system to a Laser Ablation-Catalytic-Combustion (LA-CC) micro-sampler system for selectively harvesting detailed sections of a solid surface for 13C analysis. This technique results in a three order of magnitude sensitivity improvement reported for our isotope measurement system compared to typical IRMS, providing new opportunities for making detailed investigations into wide ranges of microbial, physical, and chemical systems. The CAS is interfaced directly to the LA CC system currently operating at a 50 μm spatial resolution. We demonstrate that particulates produced by a Nd:YAG laser (λ=266nm) are isotopically homogenous with the parent material as measured by both IRMS and the CAS system. An improved laser ablation system operating at 193 nm with a spatial resolution of 2 microns or better is under development which will demonstrate the utility of the CAS system for sample sizes too low for IRMS. The improved sensitivities and optimized spatial targeting of such a system could interrogate targets as detailed as small cell clusters or intergrain organic deposits and could enhance ability to track biogeochemical carbon cycling.

  9. 29 CFR 4.174 - Meeting requirements for holiday fringe benefits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... contract, all employees who work during the first week would be entitled to holiday pay for that day. For... 29 Labor 1 2010-07-01 2010-07-01 true Meeting requirements for holiday fringe benefits. 4.174 Section 4.174 Labor Office of the Secretary of Labor LABOR STANDARDS FOR FEDERAL SERVICE CONTRACTS...

  10. 26 CFR 1.132-6 - De minimis fringes.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... employer provides the fringes to each individual employee. For example, if an employer provides a free meal in kind to one employee on a daily basis, but not to any other employee, the value of the meals is... workforce the meals are provided “infrequently.” (2) Employer-measured frequency. Notwithstanding the rule...

  11. 26 CFR 1.132-6 - De minimis fringes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... employer provides the fringes to each individual employee. For example, if an employer provides a free meal in kind to one employee on a daily basis, but not to any other employee, the value of the meals is... workforce the meals are provided “infrequently.” (2) Employer-measured frequency. Notwithstanding the rule...

  12. 45 CFR 1301.32 - Limitations on costs of development and administration of a Head Start program.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false Limitations on costs of development and... administrative staff functions such as the costs allocated to fringe benefits, travel, per diem, transportation... staff functions, such as the allocable costs of fringe benefits, travel, per diem and transportation...

  13. 29 CFR 5.31 - Meeting wage determination obligations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... fringe benefits where both are contained in a wage determination applicable to his laborers or mechanics in the following ways: (1) By paying not less than the basic hourly rate to the laborers or mechanics... to the laborers or mechanics and by making contributions for “bona fide” fringe benefits in a total...

  14. 29 CFR 5.31 - Meeting wage determination obligations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... fringe benefits where both are contained in a wage determination applicable to his laborers or mechanics in the following ways: (1) By paying not less than the basic hourly rate to the laborers or mechanics... to the laborers or mechanics and by making contributions for “bona fide” fringe benefits in a total...

  15. 29 CFR 5.31 - Meeting wage determination obligations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... fringe benefits where both are contained in a wage determination applicable to his laborers or mechanics in the following ways: (1) By paying not less than the basic hourly rate to the laborers or mechanics... to the laborers or mechanics and by making contributions for “bona fide” fringe benefits in a total...

  16. 29 CFR 5.31 - Meeting wage determination obligations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... fringe benefits where both are contained in a wage determination applicable to his laborers or mechanics in the following ways: (1) By paying not less than the basic hourly rate to the laborers or mechanics... to the laborers or mechanics and by making contributions for “bona fide” fringe benefits in a total...

  17. Fringe Benefits Available to Public School Teachers in the Southeast. Research Report. Occasional Papers in Educational Policy Analysis.

    ERIC Educational Resources Information Center

    Mabry, Rodney H.; And Others

    This project measured and evaluated the fringe benefit element of the teacher compensation package available in the 12 Southeastern Regional Council member states: Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, Virginia, and West Virgina. Data were collected by contacting members…

  18. The western prairie fringed orchid (Platanthera praeclara): monitoring and research

    Treesearch

    Ardell J. Bjugstad; William Fortune

    1989-01-01

    Western prairie fringed orchid (Platanthera praeclara Sheviak and Bowles) Populations at one time extended from southwestern Missouri north to northwestern Minnesota, and from eastern Iowa to the Sandhills of north central Nebraska. It is listed as endangered in Iowa and Minnesota and candidate for threatened or endangered status in Kansas, Missouri...

  19. 48 CFR 22.406-2 - Wages, fringe benefits, and overtime.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... exact cash amounts. In these cases, the hourly cash equivalent of the cost of these items shall be... the contractor's contributions, costs, or payment of cash equivalents for fringe benefits. Overtime... cash to the laborer or mechanic, or deducted from payments under the conditions set forth in 29 CFR 3.5...

  20. A Study of Benefits and Selected Salaries of California Community College Districts.

    ERIC Educational Resources Information Center

    Kern Community Coll. District, Bakersfield, CA.

    In an effort to assess the overall fringe benefit programs of community college districts in California and to determine the dollar amounts paid certificated employees, fringe benefit and salary remuneration were calculated for all 70 districts in the state. Study findings included the following: (1) 13 districts offered a "cafeteria…

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