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Sample records for line edge roughness

  1. Fingerprinting the type of line edge roughness

    NASA Astrophysics Data System (ADS)

    Fernández Herrero, A.; Pflüger, M.; Scholze, F.; Soltwisch, V.

    2017-06-01

    Lamellar gratings are widely used diffractive optical elements and are prototypes of structural elements in integrated electronic circuits. EUV scatterometry is very sensitive to structure details and imperfections, which makes it suitable for the characterization of nanostructured surfaces. As compared to X-ray methods, EUV scattering allows for steeper angles of incidence, which is highly preferable for the investigation of small measurement fields on semiconductor wafers. For the control of the lithographic manufacturing process, a rapid in-line characterization of nanostructures is indispensable. Numerous studies on the determination of regular geometry parameters of lamellar gratings from optical and Extreme Ultraviolet (EUV) scattering also investigated the impact of roughness on the respective results. The challenge is to appropriately model the influence of structure roughness on the diffraction intensities used for the reconstruction of the surface profile. The impact of roughness was already studied analytically but for gratings with a periodic pseudoroughness, because of practical restrictions of the computational domain. Our investigation aims at a better understanding of the scattering caused by line roughness. We designed a set of nine lamellar Si-gratings to be studied by EUV scatterometry. It includes one reference grating with no artificial roughness added, four gratings with a periodic roughness distribution, two with a prevailing line edge roughness (LER) and another two with line width roughness (LWR), and four gratings with a stochastic roughness distribution (two with LER and two with LWR). We show that the type of line roughness has a strong impact on the diffuse scatter angular distribution. Our experimental results are not described well by the present modelling approach based on small, periodically repeated domains.

  2. Mechanistic simulation of line-edge roughness

    NASA Astrophysics Data System (ADS)

    Biafore, John J.; Smith, Mark D.; Robertson, Stewart A.; Graves, Trey

    2007-03-01

    Physically-based photoresist models, such as those in PROLITH, have been very successful in describing photolithography from a continuum standpoint. These models allow engineers to accurately predict the final resist CD on the wafer and to analyze process robustness. However, as the critical dimension continues to shrink, yield-limiting phenomena are observed that are related to the molecular nature and reaction kinetics of photoresist materials. An example of these phenomena is line-edge roughness (LER). In this paper, the origin of LER is hypothesized to be caused by fluctuations occurring in the initial position of the reactants, fluctuations during the exposure process (shot noise) and fluctuations occurring during thermally-induced reaction-diffusion (post-exposure bake). We have developed a lattice-based mechanistic simulator to better understand the stochastic nature of reactant initial position, the exposure step, the importance of the discrete nature of the reactants, the coupling to the deprotection kinetics and the deep complexity evident in the diffusion-limited acid-quencher reaction.

  3. Line edge roughness frequency analysis for SAQP process

    NASA Astrophysics Data System (ADS)

    Sun, Lei; Zhang, Xiaoxiao; Levi, Shimon; Ge, Adam; Zhou, Hua; Wang, Wenhui; Krishnan, Navaneetha; Chen, Yulu; Verduijn, Erik; Kim, Ryoung-han

    2016-03-01

    The line edge roughness (LER) and line width roughness (LWR) transfer in a self-aligned quadruple patterning (SAQP) process is shown for the first time. Three LER characterization methods, including conventional standard deviation method, power spectral density (PSD) method and frequency domain 3-sigma method, are used in the analysis. The wiggling is also quantitatively characterized for each SAQP step with a wiggling factor. This work will benefit both process optimization and process monitoring.

  4. Scaling law governing the roughness of the swash edge line

    NASA Astrophysics Data System (ADS)

    Bormashenko, E.; Musin, A.; Grynyov, R.

    2014-09-01

    The paper is devoted to the analysis of the shape of the swash edge line. Formation of the swash boundary is treated as an interfacial phenomenon. The simplest quantitative characteristic of the roughness of interface is its width w, defined as the root-mean-square fluctuation around the average position. For rough interfaces, the scaling with size of the system L is observed in the form w(L)~Lζ. The concept of scaling supplies a simple framework for classifying interfaces. It is suggested that the fine structure of the swash boundary results from the combined action of the pinning force applied by random defects of the beach and elasticity of distorted swash boundary. The roughness of the swash front was studied at the Mediterranean Sea coast for uprush and backwash flows. Value of exponent ζ for receding swash front line was 0.64 +/- 0.02, when in the case of advancing swash the value 0.73 +/- 0.03 was calculated. The scaling exponent established for the receding phase of the swash is very close to the values of the exponent established for the roughness of the triple line for water droplets deposited on rough surfaces, crack propagation front in Plexiglas, and for the motion of a magnetic domain walls.

  5. Scaling law governing the roughness of the swash edge line

    PubMed Central

    Bormashenko, E.; Musin, A.; Grynyov, R.

    2014-01-01

    The paper is devoted to the analysis of the shape of the swash edge line. Formation of the swash boundary is treated as an interfacial phenomenon. The simplest quantitative characteristic of the roughness of interface is its width w, defined as the root-mean-square fluctuation around the average position. For rough interfaces, the scaling with size of the system L is observed in the form w(L)∝Lζ. The concept of scaling supplies a simple framework for classifying interfaces. It is suggested that the fine structure of the swash boundary results from the combined action of the pinning force applied by random defects of the beach and elasticity of distorted swash boundary. The roughness of the swash front was studied at the Mediterranean Sea coast for uprush and backwash flows. Value of exponent ζ for receding swash front line was 0.64 ± 0.02, when in the case of advancing swash the value 0.73 ± 0.03 was calculated. The scaling exponent established for the receding phase of the swash is very close to the values of the exponent established for the roughness of the triple line for water droplets deposited on rough surfaces, crack propagation front in Plexiglas, and for the motion of a magnetic domain walls. PMID:25175319

  6. Level crossing methodology applied to line-edge roughness characterization

    NASA Astrophysics Data System (ADS)

    Mack, Chris A.; Brunner, Timothy A.; Chen, Xuemei; Sun, Lei

    2017-03-01

    Stochastic-induced roughness of lithographic features continues to be of great concern due to its impact on semiconductor devices. In particular, rare events (large deviations in edge positions due to roughness) can cause catastrophic failure of a chip, but are hard to predict. Here, a new methodology, the level crossing method, is used to characterize the statistical behavior of edge roughness with the goal of predicting extreme events. Using experimental results from EUV lithography, the distribution of edge deviations was found to have tails significantly heavier than a normal distribution. While further work is required, these heavy tails could prove problematic when EUV is used in high volume manufacturing.

  7. Multitaper and multisegment spectral estimation of line-edge roughness

    NASA Astrophysics Data System (ADS)

    Luo, Yao; Savari, Serap A.

    2017-03-01

    Line-edge roughness (LER) has important impacts on the quality of semiconductor device performance, and power spectrum estimates are useful tools in characterizing it. These estimates are often obtained by taking measurements of many lines and averaging a classical power spectrum estimate from each one. While this approach improves the variance of the estimate there are disadvantages to the collection of many measurements with current microscopy techniques. We propose techniques with widespread application in other fields which simultaneously reduce data requirements and variance of LER power spectrum estimates over current approaches at the price of computational complexity. Multitaper spectral analysis uses an orthogonal collection of data windowing functions or tapers on a set of data to obtain a set of approximately statistically independent spectrum estimates. The Welch overlapped segment averaging spectrum estimate is an earlier approach to reusing data. There are known techniques to calculate error bars for these families of spectrum estimators, and we experiment with random rough lines simulated by Mack's technique based on the Thorsos method.

  8. An OCD perspective of line edge and line width roughness metrology

    NASA Astrophysics Data System (ADS)

    Bonam, Ravi; Muthinti, Raja; Breton, Mary; Liu, Chi-Chun; Sieg, Stuart; Seshadri, Indira; Saulnier, Nicole; Shearer, Jeffrey; Patlolla, Raghuveer; Huang, Huai

    2017-03-01

    Metrology of nanoscale patterns poses multiple challenges that range from measurement noise, metrology errors, probe size etc. Optical Metrology has gained a lot of significance in the semiconductor industry due to its fast turn around and reliable accuracy, particularly to monitor in-line process variations. Apart from monitoring critical dimension, thickness of films, there are multiple parameters that can be extracted from Optical Metrology models3. Sidewall angles, material compositions etc., can also be modeled to acceptable accuracy. Line edge and Line Width roughness are much sought of metrology following critical dimension and its uniformity, although there has not been much development in them with optical metrology. Scanning Electron Microscopy is still used as a standard metrology technique for assessment of Line Edge and Line Width roughness. In this work we present an assessment of Optical Metrology and its ability to model roughness from a set of structures with intentional jogs to simulate both Line edge and Line width roughness at multiple amplitudes and frequencies. We also present multiple models to represent roughness and extract relevant parameters from Optical metrology. Another critical aspect of optical metrology setup is correlation of measurement to a complementary technique to calibrate models. In this work, we also present comparison of roughness parameters extracted and measured with variation of image processing conditions on a commercially available CD-SEM tool.

  9. Modelling Line Edge Roughness in Periodic Line-Space Structures by Fourier Optics to Improve Scatterometry

    NASA Astrophysics Data System (ADS)

    Gross, H.; Heidenreich, S.; Henn, M.-A.; Dai, G.; Scholze, F.; Bär, M.

    2014-01-01

    In the present paper, we propose a 2D-Fourier transform method as a simple and efficient algorithm for stochastical and numerical studies to investigate the systematic impacts of line edge roughness on light diffraction pattern of periodic line-space structures. The key concept is the generation of ensembles of rough apertures composed of many slits, to calculate the irradiance of the illuminated rough apertures far away from the aperture plane, and a comparison of their light intensities to those of the undisturbed, 'non-rough' aperture. We apply the Fraunhofer approximation and interpret the rough apertures as binary 2D-gratings to compute their diffraction patterns very efficiently as the 2D-Fourier transform of the light distribution of the source plane. The rough edges of the aperture slits are generated by means of power spectrum density (PSD) functions, which are often used in metrology of rough geometries. The mean efficiencies of the rough apertures reveal a systematic exponential decrease for higher diffraction orders if compared to the diffraction pattern of the unperturbed aperture. This confirms former results, obtained by rigorous calculations with computational expensive finite element methods (FEM) for a simplified roughness model. The implicated model extension for scatterometry by an exponential damping factor for the calculated efficiencies allows to determine the standard deviation σ_r of line edge roughness along with the critical dimensions (CDs), i.e., line widths, heights and other profile properties in the sub-micrometer range. First comparisons with the corresponding roughness value determined by 3D atomic force microscopy (3D AFM) reveal encouraging results.

  10. Line-edge roughness performance targets for EUV lithography

    NASA Astrophysics Data System (ADS)

    Brunner, Timothy A.; Chen, Xuemei; Gabor, Allen; Higgins, Craig; Sun, Lei; Mack, Chris A.

    2017-03-01

    Our paper will use stochastic simulations to explore how EUV pattern roughness can cause device failure through rare events, so-called "black swans". We examine the impact of stochastic noise on the yield of simple wiring patterns with 36nm pitch, corresponding to 7nm node logic, using a local Critical Dimension (CD)-based fail criteria Contact hole failures are examined in a similar way. For our nominal EUV process, local CD uniformity variation and local Pattern Placement Error variation was observed, but no pattern failures were seen in the modest (few thousand) number of features simulated. We degraded the image quality by incorporating Moving Standard Deviation (MSD) blurring to degrade the Image Log-Slope (ILS), and were able to find conditions where pattern failures were observed. We determined the Line Width Roughness (LWR) value as a function of the ILS. By use of an artificial "step function" image degraded by various MSD blur, we were able to extend the LWR vs ILS curve into regimes that might be available for future EUV imagery. As we decreased the image quality, we observed LWR grow and also began to see pattern failures. For high image quality, we saw CD distributions that were symmetrical and close to Gaussian in shape. Lower image quality caused CD distributions that were asymmetric, with "fat tails" on the low CD side (under-exposed) which were associated with pattern failures. Similar non-Gaussian CD distributions were associated with image conditions that caused missing contact holes, i.e. CD=0.

  11. Comparison of left and right side line edge roughness in lithography

    NASA Astrophysics Data System (ADS)

    Sun, Lei; Saulnier, Nicole; Beique, Genevieve; Verduijn, Erik; Wang, Wenhui; Xu, Yongan; Tang, Hao; Chen, Yulu; Kim, Ryoung-han; Arnold, John; Felix, Nelson; Colburn, Matthew

    2016-03-01

    The left side and right side line edge roughnesses (LER) of a line are compared for different conditions, such as through pitch, through critical dimension (CD), from horizontal to vertical line direction, from litho to etch. The investigation shows that the left and right side LER from lithography process are the same, however, the metrology can cause a 4-25% increase in the measured right side LER. The LER difference is related to the CDSEM e-beam scan direction.

  12. Nondestructive analysis of lithographic patterns with natural line edge roughness from Mueller matrix ellipsometric data

    NASA Astrophysics Data System (ADS)

    Chen, Xiuguo; Shi, Yating; Jiang, Hao; Zhang, Chuanwei; Liu, Shiyuan

    2016-12-01

    Mueller matrix ellipsometry (MME) is applied to characterize lithographic patterns with natural line edge roughness (LER). A computationally efficient approach based on effective medium approximation is proposed to model the effects of LER in MME measurements. We present both the theoretical and experimental results on lithographic patterns with realistic LER which demonstrate that MME in combination with the proposed effective modeling method is capable of quantifying LER amplitudes. Quantitative comparisons between the MME and scanning electron microscopy measured results also reveal the strong potential of this technique for in-line nondestructive line roughness monitoring.

  13. Implications of image plane line-edge roughness requirements on extreme ultraviolet mask specifications

    SciTech Connect

    Naulleau, P. P.; George, Simi A.

    2009-02-13

    Line-edge roughness (LER) and the related effect of contact size variation remain as significant challenges facing the commercialization of extreme ultraviolet (EUV) lithography. LER is typically viewed as a resist problem; however, recent simulation results have shown that the mask can indeed be an important contributor. Problems arise from both mask absorber LER as well as mask multilayer roughness leading to random phase variations in the reflected beam (see Fig. 1). The latter effect is especially important as higher coherence off-axis illumination conditions are used and defocus is considered. Here we describe these effect in detail and explore how they will impact EUV mask requirements for the 22-nm half-pitch node and beyond. Figure 2 shows modeling results for 22-nm lines printed in a 0.32-numerical aperture system with 100-nm defocus assuming a mask with 0.24-nm rms multilayer roughness and no absorber edge roughness (unlike the example in Fig. 1). The impact of the phase roughness on the printed line-edge roughness is clearly evident and demonstrates the basic problem with mask roughness. The more detailed modeling-based analysis to be presented will account for performance throughout the process window as well as non-stochastic resist effects. We note that the mean-field resist effect is important to consider because, in practice, the resist is the limiting resolution element in the system and therefore dominates the mask-error enhancement factor (MEEF). As is typically the case with projection-optic-induced MEEF, the resist-induced MEEF will lead to even tighter mask requirements. Note that we do not consider resist stochastic effects since the purpose of this study is isolate mask-induced sources of image-plane roughness.

  14. Line edge roughness frequency analysis during pattern transfer in semiconductor fabrication

    NASA Astrophysics Data System (ADS)

    Sun, Lei; Wang, Wenhui; Beique, Genevieve; Sung, Min Gyu; Wood, Obert R.; Kim, Ryoung-Han

    2015-07-01

    Line edge roughness (LER) and line width roughness (LWR) are analyzed based on the frequency domain 3σ LER characterization methodology during pattern transfer in a self-aligned double patterning (SADP) process. The power spectrum of the LER/LWR is divided into three regions: low frequency, middle frequency, and high frequency regions. Three standard deviation numbers are used to characterize the LER/LWR in the three frequency regions. Pattern wiggling is also detected quantitatively during LER/LWR transfer in the SADP process.

  15. Challenges in line edge roughness metrology in directed self-assembly lithography: placement errors and cross-line correlations

    NASA Astrophysics Data System (ADS)

    Constantoudis, Vassilios; Papavieros, George; Gogolides, Evangelos; Pret, Alessandro Vaglio; Pathangi, Hari; Gronheid, Roel

    2017-04-01

    Directed self-assembly (DSA) lithography poses challenges in line edge roughness (LER)/line width roughness metrology due to its self-organized and pitch-based nature. To cope with these challenges, a characterization approach with metrics and/or updates of the older ones is required. To this end, we focus on two specific challenges of DSA line patterns: (a) the large correlations between the left and right edges of a line (line wiggling) and (b) the cross-line correlations, i.e., the resemblance of wiggling fluctuations of nearby lines. The first is quantified by the line center roughness whose low-frequency part is related to the local placement errors of device structures. For the second, we introduce the c-factor correlation function, which quantifies the strength of the correlations between lines versus their horizontal distance in pitches. The proposed characterization approach is first illustrated and explained in synthesized scanning electron microscope images with full control of their dimensional and roughness parameters; it is then applied to the analysis of line/space patterns obtained with the Liu-Nealey flow (post-Polymethyl methacrylate removal and pattern transfer), revealing the effects of pattern transfer on roughness and uniformity. Finally, we calculate the c-factor function of various next-generation lithography techniques and show their distinct footprint on the extent of cross-line correlations.

  16. The effect of sidewall roughness on line edge roughness in top-down scanning electron microscopy images

    NASA Astrophysics Data System (ADS)

    Verduin, T.; Lokhorst, S. R.; Kruit, P.; Hagen, C. W.

    2015-03-01

    We have investigated in a numerical study the determination of sidewall roughness (SWR) from top down scanning electron microscopy (SEM) images. In a typical metrology application, top-down SEM images are acquired in a (critical-dimension) SEM and the roughness is analyzed. However, the true size, shape and roughness characteristics of resist features are not fully investigated in the analysis of top-down SEM images. In reality, rough resist features are complex three-dimensional structures and the characterization naturally extends to the analysis of SWR. In this study we randomly generate images of rough lines and spaces, where the lines are made of PMMA on a silicon substrate. The lines that we study have a length of 2 µm, a width of 32nm and a height of 32 nm. The SWR is modeled by using the power spectral density (PSD) function of Palasantzas, which characterizes roughness by the standard deviation σ, correlation length ξ and roughness exponent α . The actual roughness is generated by application of the method of Thorsos in two dimensions. The images are constructed by using a home-built program for simulating electron-specimen interactions. The program that we have developed is optimized for complex arbitrary geometries and large number of incident low energy primary electrons by using multi-core CPUs and GPUs. The program uses the dielectric function model for inelastic scattering events and has an implementation specifically for low energy electrons. A satisfactory comparison is made between the secondary electron yields from the home-built program and another program found in literature. In order to reduce the risk of shrinkage, we use a beam energy of 300 eV and a spot size of 3 nm. Each pixel is exposed with 20 electrons on average (≍ 276 µC/cm2), following the Poisson distribution to account for illumination shot noise. We have assumed that the detection of electrons is perfect and does not introduce additional noise. We measure line edge

  17. Replicated mask surface roughness effects on EUV lithographic pattering and line edge roughness

    SciTech Connect

    George, Simi A.; Naulleau, Patrick P.; Gullikson, Eric M.; Mochi, Iacopo; Salmassi, Farhad; Goldberg, Kenneth A.; Anderson, Erik H.

    2011-03-11

    To quantify the roughness contributions to speckle, a programmed roughness substrate was fabricated with a number of areas having different roughness magnitudes. The substrate was then multilayer coated. Atomic force microscopy (AFM) surface maps were collected before and after multilayer deposition. At-wavelength reflectance and total integrated scattering measurements were also completed. Angle resolved scattering based power spectral densities are directly compared to the AFM based power spectra. We show that AFM overpredicts the roughness in the picometer measurements range. The mask was then imaged at-wavelength for the direct characterization of the aerial image speckle using the SEMATECH Berkeley Actinic Inspection Tool (AIT). Modeling was used to test the effectiveness of the different metrologies in predicting the measured aerial-image speckle. AIT measured contrast values are 25% or more than the calculated image contrast values obtained using the measured rms roughness input. The extent to which the various metrologies can be utilized for specifying tolerable roughness limits on EUV masks is still to be determined. Further modeling and measurements are being planned.

  18. Determination of optimal parameters for CD-SEM measurement of line-edge roughness

    NASA Astrophysics Data System (ADS)

    Bunday, Benjamin D.; Bishop, Michael; McCormack, Donald W., Jr.; Villarrubia, John S.; Vladar, Andras E.; Dixson, Ronald; Vorburger, Theodore V.; Orji, N. G.; Allgair, John A.

    2004-05-01

    The measurement of line-edge roughness (LER) has recently become a topic of concern in the litho-metrology community and the semiconductor industry as a whole. The Advanced Metrology Advisory Group (AMAG), a council composed of the chief metrologists from the International SEMATECH (ISMT) consortium"s Member Companies and from the National Institute of Standards and Technology (NIST), has a project to investigate LER metrics and to direct the critical dimension scanning electron microscope (CD-SEM) supplier community towards a semiconductor industry-backed, standardized solution for implementation. The 2003 International Technology Roadmap for Semiconductors (ITRS) has included a new definition for roughness. The ITRS envisions root mean square measurements of edge and width roughness. There are other possible metrics, some of which are surveyed here. The ITRS envisions the root mean square measurements restricted to roughness wavelengths falling within a specified process-relevant range and with measurement repeatability better than a specified tolerance. This study addresses the measurement choices required to meet those specifications. An expression for the length of line that must be measured and the spacing of measurement positions along that length is derived. Noise in the image is shown to produce roughness measurement errors that have both random and nonrandom (i.e., bias) components. Measurements are reported on both UV resist and polycrystalline silicon in special test patterns with roughness typical for those materials. These measurements indicate that the sensitivity of a roughness measurement to noise depends importantly both on the choice of edge detection algorithm and the quality of the focus. Measurements are less sensitive to noise when a model-based or sigmoidal fit algorithm is used and when the images are in good focus. Using the measured roughness characteristics for UV resist lines and applying the ITRS requirements for the 90 nm technology

  19. System-level line-edge roughness limits in extreme ultraviolet lithography

    SciTech Connect

    Jones, Juanita; Naulleau, Patrick P; Niakoula, Dimitra; Zhang, Guojing

    2008-02-13

    As critical dimensions shrink, line edge and width roughness (LER and LWR) become of increasing concern. Traditionally LER is viewed as a resist-limited effect; however, as critical dimensions shrink and LER requirements become proportionally more stringent, system-level effects begin to play an important role. Recent advanced EUV resist testing results have demonstrated lower bounds on achievable LER at the level of approximately 2 to 3 nm. Here we use modeling to demonstrate that a significant portion of this low bound may in fact be do to system-level effects and in particular the mask. Of concern are both LER on the mask as well as roughness of the multilayer reflector. Modeling also shows roughness (flare) in the projection optics not to be of concern.

  20. CD-SEM measurement line-edge roughness test patterns for 193-nm lithography

    NASA Astrophysics Data System (ADS)

    Bunday, Benjamin D.; Bishop, Michael; Villarrubia, John S.; Vladar, Andras E.

    2003-05-01

    The measurement of line-edge roughness (LER) has recently become a major topic of concern in the litho-metrology community and the semiconductor industry as a whole, as addressed in the 2001 ITRS roadmap. The Advanced Metrology Advisory Group (AMAG, a council composed of the chief CD-metrologists from the International SEMATECH consortium's Member Companies and from the National Institute of Standards and Technology, NIST) has begun a project to investigate this issue and to direct the CD-SEM supplier community towards a semiconductor industry-backed solution for implementation. The AMAG group has designed and built a 193 nm reticle that includes structures implementing a number of schemes to intentionally cause line edge roughness of various spatial frequencies and amplitudes. The lithography of these structures is in itself of interest to the litho-metrology community and will be discussed here. Measurements on different CD-SEMs of major suppliers will be used to comparatively demonstrate the current state of LER measurement. These measurements are compared to roughness determined off-line by analysis of top-down images from these tools. While no official standard measurement algorithm or definition of LER measurement exists, definitions used in this work are presented and compared in use. Repeatability of the measurements and factors affecting their accuracy will be explored, as well as how CD-SEM parameters can effect the measurements.

  1. Stochastic simulation studies of line-edge roughness in block copolymer lithography.

    PubMed

    Kim, Sang-Kon

    2014-08-01

    Because photoresist has the uncertain triangle relation among the higher resolution, the lower line-edge-roughness (LER) (or line-with-roughness (LWR)), and the improved sensitivity, for below 20-nm pattern formation, this relation makes hard to use the optical lithography. Directed self-assembly (DSA) has been considered as a potential candidate to extend the resolution limit of the optical lithography. The effects of DSA processing and DSA molecular geometry on LER should be well understood in order to meet the ITRS lithographic specifications. In this paper, for the optical lithography and the block copolymer (BCP) lithography such as graphoepitaxy, LER behavior is modeled by the stochastic methods such as the Monte Carlo method and the dissipative particle dynamics (DPD) method. Simulation results explain that the LER of the BCP lithography is smaller than that of the optical lithography because of a self-healing capability of block copolymers.

  2. Separating the optical contributions to line-edge roughness in EUV lithography using stochastic simulations

    NASA Astrophysics Data System (ADS)

    Chunder, Anindarupa; Latypov, Azat; Chen, Yulu; Biafore, John J.; Levinson, Harry J.; Bailey, Todd

    2017-03-01

    Minimization and control of line-edge roughness (LER) and contact-edge roughness (CER) is one of the current challenges limiting EUV line-space and contact hole printability. One significant contributor to feature roughness and CD variability in EUV is photon shot noise (PSN); others are the physical and chemical processes in photoresists, known as resist stochastic effect. Different approaches are available to mitigate each of these contributions. In order to facilitate this mitigation, it is important to assess the magnitude of each of these contributions separately from others. In this paper, we present and test a computational approach based on the concept of an `ideal resist'. An ideal resist is assumed to be devoid of all resist stochastic effects. Hence, such an ideal resist can only be simulated as an `ideal resist model' (IRM) through explicit utilization of the Poisson statistics of PSN2 or direct Monte Carlo simulation of photon absorption in resist. LER estimated using IRM, thus quantifies the exclusive contribution of PSN to LER. The result of the simulation study done using IRM indicates higher magnitude of contribution (60%) from PSN to LER with respect to total or final LER for a sufficiently optimized high dose `state of the art' EUV chemically amplified resist (CAR) model.

  3. CD-SEM measurement line edge roughness test patterns for 193 nm lithography

    NASA Astrophysics Data System (ADS)

    Bunday, Benjamin D.; Bishop, Michael; Villarrubia, John S.; Vladar, Andras E.

    2003-07-01

    The measurement of line-edge roughness (LER) has recently become a major topic of concern in the litho-metrology community and the semiconductor industry as a whole, as addressed in the 2001 International Technology Roadmap for Semiconductors (ITRS) roadmap. The Advanced Metrology Advisory Group (AMAG, a council composed of the chief metrologists from the International SEMATECH (ISMT) consortium"s Member Companies and from the National Institute of Standards and Technology (NIST) has begun a project to investigate this issue and to direct the critical dimension scanning electron microscope (CD-SEM) supplier community towards a semiconductor industry-backed solution for implementation. The AMAG group has designed and built a 193 nm reticle that includes structures implementing a number of schemes to intentionally cause line edge roughness of various spatial frequencies and amplitudes. The lithography of these structures is in itself of interest to the litho-metrology community and will be discussed here. These structures, along with several other photolithography process variables, have been used to fabricate a set of features of varying roughness value and structure which span the LER process space of interest. These references are, in turn, useful for evaluation of LER measurement capability. Measurements on different CD-SEMs of major suppliers were used to demonstrate the current state of LER measurement. These measurements were compared to roughness determined off-line by analysis of top-down images from these tools. While no official standard measurement algorithm or definition of LER measurement exists, definitions used in this work are presented and compared in use. Repeatability of the measurements and factors affecting their accuracy were explored, as well as how CD-SEM parameters can affect the measurements.

  4. Line-edge roughness induced single event transient variation in SOI FinFETs

    NASA Astrophysics Data System (ADS)

    Weikang, Wu; Xia, An; Xiaobo, Jiang; Yehua, Chen; Jingjing, Liu; Xing, Zhang; Ru, Huang

    2015-11-01

    The impact of process induced variation on the response of SOI FinFET to heavy ion irradiation is studied through 3-D TCAD simulation for the first time. When FinFET biased at OFF state configuration (Vgs = 0, Vds = Vdd) is struck by a heavy ion, the drain collects ionizing charges under the electric field and a current pulse (single event transient, SET) is consequently formed. The results reveal that with the presence of line-edge roughness (LER), which is one of the major variation sources in nano-scale FinFETs, the device-to-device variation in terms of SET is observed. In this study, three types of LER are considered: type A has symmetric fin edges, type B has irrelevant fin edges and type C has parallel fin edges. The results show that type A devices have the largest SET variation while type C devices have the smallest variation. Further, the impact of the two main LER parameters, correlation length and root mean square amplitude, on SET variation is discussed as well. The results indicate that variation may be a concern in radiation effects with the down scaling of feature size.

  5. Optical scatterometry system for detecting specific line edge roughness of resist gratings subjected to detector noises

    NASA Astrophysics Data System (ADS)

    Lee, Yen-Min; Li, Jia-Han; Wang, Fu-Min; Cheng, Hsin-Hung; Shen, Yu-Tian; Tsai, Kuen-Yu; Shieh, Jason J.; Chen, Alek C.

    2014-06-01

    The Fourier scatterometry model was used to measure the ZEP 520A electron beam resist lines with specific line edge roughness (LER). By obtaining the pupils via an objective lens, the angle-resolved diffraction spectrum was collected efficiently without additional mechanical scanning. The concavity of the pupil was considered as the weight function in specimen recognition. A series of white noises was examined in the model, and the tolerant white noise levels for different system numerical apertures (NAs) were reported. Our numerical results show that the scatterometry model of a higher NA can identify a target with a higher white noise level. Moreover, the fabricated ZEP 520A electron beam resist gratings with LER were measured by using our model, and the fitting results were matched with scanning electron microscope measurements.

  6. Simulation of amine concentration dependence on line edge roughness after development in electron beam lithography

    NASA Astrophysics Data System (ADS)

    Saeki, Akinori; Kozawa, Takahiro; Tagawa, Seiichi; Cao, Heidi B.; Deng, Hai; Leeson, Michael J.

    2008-07-01

    Line edge roughness (LER) of chemically amplified (CA) resist has evolved as a major class of issues when the required fabrication accuracy of future nanolithography gets close to the limit of materials. Near the material limit, processes have a significant impact on the limit of resist performance. In order to provide an insight into the mechanism of LER formation and survey the performance limit of CA resists, the LERs after development in positive-tone CA resist for electron beam lithography were investigated in terms of their dependences on the amine (quencher of proton/acid) concentration and exposure dose. The latent images formed during the acid formation and diffusion processes were simulated by a Monte Carlo technique. The development process described by Mack's dissolution model was incorporated into the simulation. The LERs (high frequency) after development are discussed from the aspects of image contrast, acid diffusion length, and topography of developed pattern.

  7. Line edge roughness induced threshold voltage variability in nano-scale FinFETs

    NASA Astrophysics Data System (ADS)

    Rathore, Rituraj Singh; Sharma, Rajneesh; Rana, Ashwani K.

    2017-03-01

    In aggressively scaled devices, the FinFET technology has become more prone to line edge roughness (LER) induced threshold voltage variability. As a result, nano scale FinFET structures face the problem of intrinsic statistical fluctuations in the threshold voltage. This paper describes the all LER induced variability of threshold voltage for 14 nm underlap FinFET using 3-D numerical simulations. It is concluded that percentage threshold voltage (VTH) fluctuations referenced with respect to rectangular FinFET can go up to 8.76%. This work has also investigated the impact of other sources of variability such as random dopant fluctuation, work function variation and oxide thickness variation on threshold voltage.

  8. Influence of line-edge roughness on multiple-gate tunnel field-effect transistors

    NASA Astrophysics Data System (ADS)

    Choi, Woo Young

    2017-04-01

    The influence of fin-line-edge roughness (fin-LER) and gate-LER on multiple-gate (MG) tunnel field-effect transistors (TFETs) has been investigated compared with MG MOSFETs by using full three-dimensional technology computer-aided design (TCAD) simulation. From simulation results, two interesting results have been observed. First, MG TFETs show much less severe gate-LER than MG MOSFETs, which means that only fin-LER can be considered when evaluating the total LER of MG TFETs. Second, TFETs show ∼3× more LER improvement than MOSFETs when their structures are changed from double-gate (DG) to triple-gate (TG) ones. Our findings provide the useful design guidelines of variation-tolerant TFETs.

  9. Influence of line edge roughness (LER) on angular resolved and on spectroscopic scatterometry

    NASA Astrophysics Data System (ADS)

    Schuster, Thomas; Rafler, Stephan; Frenner, Karsten; Osten, Wolfgang

    2008-09-01

    Scatterometry or optical CD metrology (OCD) has become one of the most common techniques in quantitative wafer metrology within the recent years. Different tool configurations are either available in commercial inspection tools or subject of recent and present research activities. Among these are normal incidence reflectometry, 2-θ scatterometry, spectroscopic ellipsometry and angle resolved Fourier scatterometry. The two latter techniques appear to be promising for future use in semiconductor fabs. Spectroscopic ellipsometry is well established, and Fourier scatterometry has become of increasing interest within the recent time. Line edge roughness, i.e. an edge position variation of printed lines in lithography, has been of less importance up to now, as its amplitude could largely be neglected with respect to the feature dimensions. This will, however, not be the case for future nodes, as on the one hand CDs are getting smaller and smaller, and on the other hand, even the absolute amplitude is expected to increase due to the higher complexity of lithography and etch processes. In this paper a comparison of scatterometric reconstructions in both spectroscopic and angle resolved techniques considering LER afflicted samples is presented. The validity and benefit of a simple effective medium model is investigated.

  10. Low-line edge roughness extreme ultraviolet photoresists of organotin carboxylates

    NASA Astrophysics Data System (ADS)

    Del Re, Ryan; Passarelli, James; Sortland, Miriam; Cardineau, Brian; Ekinci, Yasin; Buitrago, Elizabeth; Neisser, Mark; Freedman, Daniel A.; Brainard, Robert L.

    2015-10-01

    Pure thin films of organotin compounds have been lithographically evaluated using extreme ultraviolet lithography (EUVL, 13.5 nm). Twenty compounds of the type R2Sn) were spin-coated from solutions in toluene, exposed to EUV light, and developed in organic solvents. Exposures produced negative-tone contrast curves and dense-line patterns using interference lithography. Contrast-curve studies indicated that the photosensitivity is linearly related to the molecular weight of the carboxylate group bound to tin. Additionally, photosensitivity was found to be linearly related to free radical stability of the hydrocarbon group bound directly to tin (R=phenyl, butyl, and benzyl). Dense-line patterning capabilities varied, but two resists in particular show exceptionally good line edge roughness (LER). A resist composed of an amorphous film of )SnCC)2 (1) achieved 1.4 nm LER at 22-nm half-pitch patterning and a resist composed of )Sn) (2) achieved 1.1 nm LER at 35-nm half-pitch at high exposure doses (600 mJ/cm2). Two photoresists that use olefin-based carboxylates, )SnCCH (3) and )SnCC (4), demonstrated better photospeeds (5 mJ/cm2 and 27 mJ/cm2) but worse LER.

  11. Silicon fin line edge roughness determination and sensitivity analysis by Mueller matrix spectroscopic ellipsometry based scatterometry

    NASA Astrophysics Data System (ADS)

    Dixit, Dhairya; O'Mullane, Samuel; Sunkoju, Sravan; Hosler, Erik R.; Kamineni, Vimal; Preil, Moshe; Keller, Nick; Race, Joseph; Muthinti, Gangadhara Raja; Diebold, Alain C.

    2015-03-01

    Measurement and control of line edge roughness (LER) is one of the most challenging issues facing patterning technology. As the critical dimensions (CD) of patterned structures decrease, LER of only a few nanometers can negatively impact device performance. Here, Mueller matrix spectroscopic ellipsometry (MMSE) based scatterometry is used to determine LER in periodic line-space structures in 28 nm pitch Si fin samples fabricated by directed selfassembly (DSA) patterning. The optical response of the Mueller matrix (MM) elements is influenced by structural parameters like pitch, CD, height, and side-wall angle (SWA), as well as the optical properties of the materials. Evaluation and decoupling MM element response to LER from other structural parameters requires sensitivity analysis using simulations of optical models that include LER. Here, an approach is developed that quantifies Si fin LER by comparing the optical responses generated by systematically varying the grating shape and measurement conditions. Finally, the validity of this approach is established by comparing the results obtained from top down scanning electron microscope (SEM) images and cross-sectional TEM image of the 28 nm pitch Si fins.

  12. Resist Thinning Effect on Nanometer-Scale Line-Edge Roughness

    NASA Astrophysics Data System (ADS)

    Kanzaki, Kenichi; Yamaguchi, Toru; Nagase, Masao; Yamazaki, Kenji; Namatsu, Hideo

    2002-11-01

    The thickness dependence of the roughness of ultrathin ({≤q} 100 nm) electron-beam resist (ZEP520) was investigated using an atomic force microscope (AFM). The roughness (linewidth fluctuations of line patterns) increased with decreasing resist thickness, especially below 30 nm. On the other hand, polymer aggregates, which are well observed in conventional resists, existed in compressed form even in this ultrathin film. In addition, the dissolution rate of the resist tended to be faster with thickness reduction. Both the existence of polymer aggregates and the fast dissolution of the entire resist polymer possibly caused the larger roughness in the ultrathin resist films.

  13. Controlling line-edge roughness and reactive ion etch lag in sub-150 nm features in borophosphosilicate glass

    SciTech Connect

    Bhatnagar, Parijat; Panda, Siddhartha; Edleman, Nikki L.; Allen, Scott D.; Wise, Richard; Mahorowala, Arpan

    2007-04-01

    We have developed a reactive ion etch (RIE) process in borophosphosilicate glass (BPSG) for 150 nm line-and-space features, where line-edge roughness (LER) complemented with RIE lag becomes a major issue. Effect of flow rates and carbon-to-fluorine atomic ratio of fluorohydrocarbon gases was utilized to achieve acceptable process window allowing lower radio frequency powers therefore obtaining acceptable LER and RIE lag in the high-resolution features etched into BPSG.

  14. Simulation of the influence of line edge roughness on the performance of deep ultraviolet wire grid polarizers

    NASA Astrophysics Data System (ADS)

    Siefke, Thomas; Rojas Hurtado, Carol B.; Dickmann, Johannes; Heusinger, Martin; Kroker, Stefanie

    2017-06-01

    Controlling the polarization of light is crucial in numerous applications such as spectroscopy, ellipsometry, photo lithography or industrial vision. Polarization control can be realized by wire grid polarizers (WGPs), which are large aspect ratio, zero order gratings. These elements provide an anisotropic transmittance depending on the polarization direction of the incident light. WGPs' high attractiveness originates from their large free aperture, while simultaneously being extremely thin. Furthermore, these elements can be easily integrated into other nano-optical devices. Recently, such elements were successfully developed for applications down to the deep ultra violet spectral range. However, at shorter wavelengths the influence of roughness of the structures poses a severe limitation on the feasible optical performance. To tackle this problem, we numerically simulated the impact of line edge roughness on the polarization properties of WPGs. Therefore, we generated edge position data of rough grating lines by means of the Thorsos method and calculated the resulting optical response by finite difference time domain method. With this procedure the influence of standard deviation, correlation length, Hurst exponents and wavelength was investigated. We find that for standard deviations of 2.5 nm and 5.0 nm the polarization contrast is reduced by a factor of 3 and 7, respectively. The polarization contrast shows a minimum for intermediate correlation lengths, while virtually no impact of the Hurst exponent is observed. This is explained by several mechanisms occurring for different ratios between the spatial frequency of the roughness and the frequency of incident light. Our theoretical findings correlate well with experimental results we retrieved with measured roughness parameters of fabricated elements.

  15. Correlation method for the measure of mask-induced line-edge roughness in extreme ultraviolet lithography

    SciTech Connect

    Naulleau, Patrick

    2009-05-25

    As critical dimensions for leading-edge semiconductor devices shrink, line-edge roughness (LER) requirements are pushing well into the single digit nanometer regime. At these scales many new sources of LER must be considered. In the case of extreme ultraviolet (EUV) lithography, modeling has shown the lithographic mask to be a source of significant concern. Here we present a correlation-based methodology for experimentally measuring the magnitude of mask contributors to printed LER. The method is applied to recent printing results from a 0.3 numerical aperture EUV microfield exposure tool. The measurements demonstrate that such effects are indeed present and of significant magnitude. The method is also used to explore the effects of illumination coherence and defocus and has been used to verify model-based predictions of mask-induced LER.

  16. Spectral analysis of the line-width and line-edge roughness transfer during self-aligned double patterning approach

    NASA Astrophysics Data System (ADS)

    Dupuy, E.; Pargon, E.; Fouchier, M.; Grampeix, H.; Pradelles, J.; Darnon, M.; Pimenta-Barros, P.; Barnola, S.; Joubert, O.

    2015-03-01

    We report a 20 nm half-pitch self-aligned double patterning (SADPP) process based on a resist-core approach. Line/space 20/20 nm features in silicon are successfully obtained with CDvariation, LWR and LER of 0.7 nm, 2.4 nm and 2.3 nm respectively. The LWR and LER are characterized at each technological step of the process using a power spectral density fitting method, which allows a spectral analysis of the roughness and the determination of unbiased roughness values. Although the SADP concept generates two asymmetric populations of lines, the final LLWR and LER are similar. We show that this SADP process allows to decrease significantly the LWR and the LER of about 62% and 48% compared to the initial photoresist patterns. This study also demonstrates that SADP is a very powerful concept to decrease CD uniformity and LWR especially in its low-frequency components to reach sub-20 nm node requirements. However, LER low-frequency components are still high and remain a key issue tot address for an optimized integration.

  17. Effective-CD: a contribution toward the consideration of line edge roughness in the scatterometric critical dimension metrology

    NASA Astrophysics Data System (ADS)

    Bilski, Bartosz; Frenner, Karsten; Osten, Wolfgang

    2017-04-01

    We present an overview of our research on the relation between line edge roughness (LER) and optical critical dimension metrology (OCD). Referring to a known fact that LER does have an impact on OCD, we discuss a novel approach that allows for its better understanding. Namely, we show that, in the presence of LER, one can observe a characteristic scatterometry-measured CD offset, which we call effective-CD. The fact that the effective-CD is characteristic renders it to be a good means of accessing the information about LER present on the CD. To assure the completeness of this overview, we begin by reviewing some previously published results, which have drawn our attention and first led us to observing the characteristic influence of LER on a CD measurement. Next, we extend our model-based simulations to confirm the presence of the effective-CD for complex-roughness models, and finally, we demonstrate an experimental verification of our effective-CD hypothesis. We are convinced that our approach will help to better understand the impact of LER on a CD measurement and will be considered a useful contribution to the development of measurement methods for challenging scenarios, in which realistic CD is affected by the presence of LER.

  18. Relationships between quencher diffusion constant and exposure dose dependences of line width, line edge roughness, and stochastic defect generation in extreme ultraviolet lithography

    NASA Astrophysics Data System (ADS)

    Kozawa, Takahiro

    2015-01-01

    Control of the acid catalytic chain reaction is essential in the pattern formation of chemically amplified resists used for the high-volume production of semiconductor devices. In this study, the relationships between the quencher diffusion constant and the exposure dose dependences of the line width, line edge roughness (LER), and stochastic defect generation were investigated assuming extreme ultraviolet (EUV) lithography. The dependence of the latent images of line-and-space patterns with 16 nm half-pitch on the quencher diffusion constant was calculated on the basis of sensitization and reaction mechanisms of chemically amplified EUV resists. The exposure latitude of the line width increased with the quencher diffusion constant. The dependences of LER and stochastic defect (bridges and pinching) generation on the deviation of the exposure dose became weak by increasing the quencher diffusion constant, similarly to the case for the dependence of the line width.

  19. Heavy metal incorporated helium ion active hybrid non-chemically amplified resists: Nano-patterning with low line edge roughness

    NASA Astrophysics Data System (ADS)

    Reddy, Pulikanti Guruprasad; Thakur, Neha; Lee, Chien-Lin; Chien, Sheng-Wei; Pradeep, Chullikkattil P.; Ghosh, Subrata; Tsai, Kuen-Yu; Gonsalves, Kenneth E.

    2017-08-01

    Helium (He) ion lithography is being considered as one of the most promising and emerging technology for the manufacturing of next generation integrated circuits (ICs) at nanolevel. However, He-ion active resists are rarely reported. In this context, we are introducing a new non-chemically amplified hybrid resist (n-CAR), MAPDSA-MAPDST, for high resolution He-ion beam lithography (HBL) applications. In the resist architecture, 2.15 % antimony is incorporated as heavy metal in the form of antimonate. This newly developed resists has successfully used for patterning 20 nm negative tone features at a dose of 60 μC/cm2. The resist offered very low line edge roughness (1.27±0.31 nm) for 20 nm line features. To our knowledge, this is the first He-ion active hybrid resist for nanopatterning. The contrast (γ) and sensitivity (E0) of this resist were calculated from the contrast curve as 0.73 and 7.2 μC/cm2, respectively.

  20. Line Edge Roughness and Cross Sectional Characterization of Sub-50 nm Structures Using Critical Dimension Small Angle X-ray Scattering

    SciTech Connect

    Wang Chengqing; Jones, Ronald L.; Lin, Eric K.; Wu Wenli; Ho, Derek L.; Villarrubia, John S.; Choi, Kwang-Woo; Clarke, James S.; Roberts, Jeanette; Bristol, Robert; Bunday, Benjamin

    2007-09-26

    The need to characterize line edge and line width roughness in patterns with sub-50 nm critical dimensions challenges existing platforms based on electron microscopy and optical scatterometry. The development of x-ray based metrology platforms provides a potential route to characterize a variety of parameters related to line edge roughness by analyzing the diffracted intensity from a periodic array of test patterns. In this study, data from a series of photoresist line/space patterns featuring programmed line width roughness are measured by critical dimension small angle x-ray scattering (CD-SAXS). For samples with designed periodic roughness, CD-SAXS provides the wavelength and amplitude of the periodic roughness through satellite diffraction peaks. For real world applications, the rate of decay of intensity, termed an effective 'Debye-Waller' factor in CD-SAXS, provides an overall measure of the defects of the patterns. CD-SAXS data are compared to values obtained from critical dimension scanning electron microscopy (CD-SEM). Correlations between the techniques exist, however significant differences are observed for the current samples. A tapered cross sectional profile provides a likely explanation for the observed differences between CD-SEM and CD-SAXS measurements.

  1. Key contributors for improvement of line width roughness, line edge roughness, and critical dimension uniformity: 15 nm half-pitch patterning with extreme ultraviolet and self-aligned double patterning

    NASA Astrophysics Data System (ADS)

    Xu, Kaidong; Souriau, Laurent; Hellin, David; Versluijs, Janko; Wong, Patrick; Vangoidsenhoven, Diziana; Vandenbroeck, Nadia; Dekkers, Harold; Shi, Xiaoping; Albert, Johan; Tan, Chi Lim; Vertommen, Johan; Coenegrachts, Bart; Orain, Isabelle; Kimura, Yoshie; Wiaux, Vincent; Boullart, Werner

    2013-10-01

    The approach for patterning 15-nm half-pitch (HP) structures using extreme ultraviolet lithography combined with self-aligned double patterning is discussed. A stack composed of a double hard mask, which allows decoupling photoresist transfer and trim, and an α-Si mandrel, which offers better mechanical properties during the mandrel and spacer patterning, is proposed. A break-down study with the patterning steps was performed to investigate the key contributors for improvement of linewidth roughness (LWR), line-edge roughness (LER), and critical dimension uniformity (CDU), targeting integrated solutions with lithography, etch, thin film deposition, and wet cleans for selected applications. Based on the optimization of these key patterning contributors, optimum LWR, LER, and CDU at 15 nm HP are demonstrated.

  2. Effects of dose shift on line width, line edge roughness, and stochastic defect generation in chemically amplified extreme ultraviolet resist with photodecomposable quencher

    NASA Astrophysics Data System (ADS)

    Kozawa, Takahiro

    2015-01-01

    In chemically amplified resists used for high-volume production of semiconductor devices, the control of acid catalytic reaction is essential for fine patterning. A basic compound, called a quencher, plays an important role in the control of acid catalytic reaction. In particular, the photodecomposable quencher is effective for the enhancement of the chemical gradient. In this study, the effects of photodecomposable quenchers on the dose shift (the deviation from the sizing dose) dependences of line width, line edge roughness (LER), and stochastic defect generation were investigated, assuming line-and-space patterns with 11 nm half-pitch. The exposure latitude of line width in a chemically amplified resist with photodecomposable quenchers was larger than that in a chemically amplified resist with conventional non-photodecomposable quenchers at sizing doses >20 mJ cm-2. By using photodecomposable quenchers, LER and the probability of stochastic defect generation were decreased, while the dose shift dependences of LER and stochastic defect generation did not significantly differ, compared with those observed using conventional non-photodecomposable quenchers.

  3. Bubble-free patterning with low line edge roughness by ultraviolet nanoimprinting using trans-1,3,3,3-tetrafluoropropene condensable gas

    NASA Astrophysics Data System (ADS)

    Suzuki, Kenta; Youn, Sung-Won; Hiroshima, Hiroshi

    2016-10-01

    Ultraviolet nanoimprint lithography (UV-NIL) in pentafluoropropane (PFP) is recognized as one of the most promising methods to achieve ultrahigh-speed UV-NIL without air bubble defects. Although liquefied PFP dissolved in the resin reduces the resin viscosity and demolding force, it also causes large shrinkage of the pattern and degrades the pattern quality compared with that achieved in air or He environments. In this work, UV-NIL in trans-1,3,3,3-tetrafluoropropene (TFP), which has a higher vapor pressure than that of PFP, was investigated with respect to throughput and pattern quality characteristics to find an alternative to PFP. Bubble-free filling of UV-NIL was demonstrated in an TFP atmosphere: the cavity-filling time was about four times shorter than that in He, and the fine values of line edge roughnesses comparable to those achieved in air or He were obtained.

  4. Effects of deprotonation efficiency of protected units on line edge roughness and stochastic defect generation in chemically amplified resist processes for 11 nm node of extreme ultraviolet lithography

    NASA Astrophysics Data System (ADS)

    Kozawa, Takahiro; Santillan, Julius Joseph; Itani, Toshiro

    2014-11-01

    The deprotonation of polymer radical cations plays an important role in the acid generation in chemically amplified resists upon exposure to ionizing radiation. In this study, the effects of the deprotonation efficiency of protected units of a resist polymer on line edge roughness (LER) and stochastic defect generation were investigated. The suppression of stochastic effects is essential for the realization of high-volume production of semiconductor devices with an 11 nm critical dimension using extreme ultraviolet (EUV) lithography. By increasing the deprotonation efficiency, the chemical contrast (latent image quality) was improved; however, the protected unit number fluctuation did not significantly change. Consequently, LER and the probability of stochastic defect generation were reduced. This effect was prominent when the protection ratio was close to 100%.

  5. Line edge roughness after development in a positive-tone chemically amplified resist of post-optical lithography investigated by Monte Carlo simulation and a dissolution model

    NASA Astrophysics Data System (ADS)

    Saeki, Akinori; Kozawa, Takahiro; Tagawa, Seiichi; Cao, Heidi B.; Deng, Hai; Leeson, Michael J.

    2008-01-01

    Line edge roughness (LER) of patterned features in chemically amplified (CA) resists is formed in the acid generation stage and expected to be moderated by the acid diffusion and development process. It is essential to obtain information on the limit of LER in order to realize next-generation lithographies such as electron beam or extreme ultraviolet. Here, we report for the first time a process simulator based on physical and chemical reaction mechanisms. The LER of a positive-tone CA resist after development is investigated by Monte Carlo simulation and Mack's dissolution model. We found that the LER (high frequency) of less than 1.2 nm is achievable, although the process conditions and material design for achieving such a small LER are strict.

  6. Characterization of the shape and line-edge roughness of polymer gratings with grazing incidence small-angle X-ray scattering and atomic force microscopy

    SciTech Connect

    Suh, Hyo Seon; Chen, Xuanxuan; Rincon-Delgadillo, Paulina A.; Jiang, Zhang; Strzalka, Joseph; Wang, Jin; Chen, Wei; Gronheid, Roel; de Pablo, Juan J.; Ferrier, Nicola; Doxastakis, Manolis; Nealey, Paul F.

    2016-04-22

    Grazing-incidence small-angle X-ray scattering (GISAXS) is increasingly used for the metrology of substrate-supported nanoscale features and nanostructured films. In the case of line gratings, where long objects are arranged with a nanoscale periodicity perpendicular to the beam, a series of characteristic spots of high-intensity (grating truncation rods, GTRs) are recorded on a two-dimensional detector. The intensity of the GTRs is modulated by the three-dimensional shape and arrangement of the lines. Previous studies aimed to extract an average cross-sectional profile of the gratings, attributing intensity loss at GTRs to sample imperfections. Such imperfections are just as important as the average shape when employing soft polymer gratings which display significant line-edge roughness. Herein are reported a series of GISAXS measurements of polymer line gratings over a range of incident angles. Both an average shape and fluctuations contributing to the intensity in between the GTRs are extracted. Lastly, the results are critically compared with atomic force microscopy (AFM) measurements, and it is found that the two methods are in good agreement if appropriate corrections for scattering from the substrate (GISAXS) and contributions from the probe shape (AFM) are accounted for.

  7. Characterization of the shape and line-edge roughness of polymer gratings with grazing incidence small-angle X-ray scattering and atomic force microscopy

    DOE PAGES

    Suh, Hyo Seon; Chen, Xuanxuan; Rincon-Delgadillo, Paulina A.; ...

    2016-04-22

    Grazing-incidence small-angle X-ray scattering (GISAXS) is increasingly used for the metrology of substrate-supported nanoscale features and nanostructured films. In the case of line gratings, where long objects are arranged with a nanoscale periodicity perpendicular to the beam, a series of characteristic spots of high-intensity (grating truncation rods, GTRs) are recorded on a two-dimensional detector. The intensity of the GTRs is modulated by the three-dimensional shape and arrangement of the lines. Previous studies aimed to extract an average cross-sectional profile of the gratings, attributing intensity loss at GTRs to sample imperfections. Such imperfections are just as important as the average shapemore » when employing soft polymer gratings which display significant line-edge roughness. Herein are reported a series of GISAXS measurements of polymer line gratings over a range of incident angles. Both an average shape and fluctuations contributing to the intensity in between the GTRs are extracted. Lastly, the results are critically compared with atomic force microscopy (AFM) measurements, and it is found that the two methods are in good agreement if appropriate corrections for scattering from the substrate (GISAXS) and contributions from the probe shape (AFM) are accounted for.« less

  8. Characterization of the shape and line-edge roughness of polymer gratings with grazing incidence small-angle X-ray scattering and atomic force microscopy

    SciTech Connect

    Suh, Hyo Seon; Chen, Xuanxuan; Rincon-Delgadillo, Paulina A.; Jiang, Zhang; Strzalka, Joseph; Wang, Jin; Chen, Wei; Gronheid, Roel; de Pablo, Juan J.; Ferrier, Nicola; Doxastakis, Manolis; Nealey, Paul F.

    2016-04-22

    Grazing-incidence small-angle X-ray scattering (GISAXS) is increasingly used for the metrology of substrate-supported nanoscale features and nanostructured films. In the case of line gratings, where long objects are arranged with a nanoscale periodicity perpendicular to the beam, a series of characteristic spots of high-intensity (grating truncation rods, GTRs) are recorded on a two-dimensional detector. The intensity of the GTRs is modulated by the three-dimensional shape and arrangement of the lines. Previous studies aimed to extract an average cross-sectional profile of the gratings, attributing intensity loss at GTRs to sample imperfections. Such imperfections are just as important as the average shape when employing soft polymer gratings which display significant line-edge roughness. Herein are reported a series of GISAXS measurements of polymer line gratings over a range of incident angles. Both an average shape and fluctuations contributing to the intensity in between the GTRs are extracted. Lastly, the results are critically compared with atomic force microscopy (AFM) measurements, and it is found that the two methods are in good agreement if appropriate corrections for scattering from the substrate (GISAXS) and contributions from the probe shape (AFM) are accounted for.

  9. Advanced edge roughness measurement application for mask metrology

    NASA Astrophysics Data System (ADS)

    Chase, D.; Kris, R.; Katz, R.; Tam, A.; Gershtein, L.; Falah, R.; Wertsman, N.

    2005-11-01

    Mask Manufacturers are continuously asked to supply reticles with reduced CD (Critical Dimension) specification, such as CD Uniformity and Mean to target. To meet this on-going trend the industry is in a quest for higher resolution metrology tools, which in-turn drives the use of SEM metrology into standard mask manufacturing process. As dimensions of integrated circuit features reduce, the negative effects of roughness of the features, and/or of components such as photo-resist and ancillary structures used to produce the features, become more pronounced since there is not necessarily a corresponding reduction of roughness with dimension reduction. As a result of the increased problems, metrics that quantify roughness of specific sections of an integrated circuit have been developed; for example, line edge roughness (LER) measures the roughness of a linear edge. This paper concentrates on one specific area of the Mask Metrology, being measurement of the different Roughness metrics of the reticle features such as lines and contacts, using a new SEM metrology tool, the Applied Materials RETicleSEM. We describe the comprehensive Roughness Analysis Algorithm package that performs precise measurements of the different Roughness metrics including Fourier analysis, auto-correlation function and correlation length. This package can be used to isolate and characterize the roughness of specific wavelength ranges that may be of interest for mask manufacturing process and/or mask quality control considerations. We conclude with sample results of Roughness Analysis on real SEM images of Reticle lines. The influence of CD roughness on the precision of measurements is considered. The proof that long-wave roughness can be one from the sources of flyers during CD measurements is presented.

  10. Experimental methodology of contact edge roughness on sub-100-nm pattern

    NASA Astrophysics Data System (ADS)

    Lee, Tae Yong; Ihm, Dongchul; Kang, Hyo Chun; Lee, Jun Bum; Lee, Byoung-Ho; Chin, Soo-Bok; Cho, Do-Hyun; Kim, Yang Hyong; Yang, Ho Dong; Yang, Kyoung Mo

    2004-05-01

    The measurement of edge roughness has become a hot issue in the semiconductor industry. Major vendors offer a variety of features to measure the edge roughness in their CD-SEMs. However, most of the features are limited by the applicable pattern types. For the line and space patterns, features such as Line Edge Roughness (LER) and Line Width Roughness (LWR) are available in current CD-SEMs. The edge roughness is more critical in contact process. However the measurement of contact edge roughness (CER) or contact space roughness (CSR) is more complicated than that of LER or LWR. So far, no formal standard measurement algorithm or definition of contact roughness measurement exists. In this article, currently available features are investigated to assess their representability for CER or CSR. Some new ideas to quantify CER and CSR were also suggested with preliminary experimental results.

  11. Sensitivity analysis and line edge roughness determination of 28-nm pitch silicon fins using Mueller matrix spectroscopic ellipsometry-based optical critical dimension metrology

    NASA Astrophysics Data System (ADS)

    Dixit, Dhairya; O'Mullane, Samuel; Sunkoju, Sravan; Gottipati, Abhishek; Hosler, Erik R.; Kamineni, Vimal; Preil, Moshe; Keller, Nick; Race, Joseph; Muthinti, Gangadhara Raja; Diebold, Alain C.

    2015-07-01

    Measurement and control of line edge roughness (LER) is one of the most challenging issues facing patterning technology. As the critical dimensions (CDs) of patterned structures decrease, an LER of only a few nanometers negatively impacts device performance. Here, Mueller matrix (MM) spectroscopic ellipsometry-based scatterometry is used to characterize LER in periodic line-space structures in 28-nm pitch Si fin samples fabricated by directed self-assembly patterning. The optical response of the MM elements is influenced by structural parameters like pitch, CDs, height, and side-wall angle, as well as the optical properties of the materials. Evaluation and decoupling MM element response to LER from other structural parameters requires sensitivity analysis using scatterometry models that include LER. Here, an approach is developed that can be used to characterize LER in Si fins by comparing the optical responses generated by systematically varying the grating shape and measurement conditions. Finally, the validity of this approach is established by comparing the results obtained from power spectral density analysis of top down scanning electron microscope images and cross-sectional transmission electron microscope image of the 28-nm pitch Si fins.

  12. Fabricating a high-resolution mask with improved line-edge roughness by using a nonchemically amplified resist and a postexposure bake

    PubMed Central

    Miyoshi, Hidetatsu; Taniguchi, Jun

    2015-01-01

    The authors have developed a high-resolution technique for fabricating photomasks at the 10-nm half-pitch logic nodes and beyond. Current mask-manufacturing techniques use a chemically amplified resist (CAR) that has a complex mechanism of acid generation, complicating the criteria for selecting the polymer and the quencher for industrial purposes. Thus, it is important to study fabricating masks with non-CARs. The authors exposed a non-CAR, diluted ZEP520A, to variable-shaped electron-beam lithography and used a postexposure bake (PEB) to modify the resist. Studying how the PEB temperature affected the non-CAR and resultant masks, the authors demonstrate that their technique can produce high-resolution structures. By measuring the critical dimensions (CDs), the authors show that the PEB shrunk, enlarged, and retained the size of 1:1 line-and-space, isolated space, and isolated line patterns, respectively. By optimizing the PEB temperature, the authors improved the line-edge roughness (LER) of the 1:1 line-and-space and isolated space CDs by ∼40%. To understand how the PEB affected the resultant structures, the authors measured the hardness of cured resists with and without a PEB at various temperatures. Optimizing the PEB temperature of the non-CAR increased the resist contrast, annealing the resist and improving the LER. As such, their technique is capable of high resolutions on the order of 20 nm. The insights the authors gained from optimizing the PEB might be useful when fabricating next-generation masks. PMID:26594597

  13. Fabricating a high-resolution mask with improved line-edge roughness by using a nonchemically amplified resist and a postexposure bake.

    PubMed

    Miyoshi, Hidetatsu; Taniguchi, Jun

    2015-11-01

    The authors have developed a high-resolution technique for fabricating photomasks at the 10-nm half-pitch logic nodes and beyond. Current mask-manufacturing techniques use a chemically amplified resist (CAR) that has a complex mechanism of acid generation, complicating the criteria for selecting the polymer and the quencher for industrial purposes. Thus, it is important to study fabricating masks with non-CARs. The authors exposed a non-CAR, diluted ZEP520A, to variable-shaped electron-beam lithography and used a postexposure bake (PEB) to modify the resist. Studying how the PEB temperature affected the non-CAR and resultant masks, the authors demonstrate that their technique can produce high-resolution structures. By measuring the critical dimensions (CDs), the authors show that the PEB shrunk, enlarged, and retained the size of 1:1 line-and-space, isolated space, and isolated line patterns, respectively. By optimizing the PEB temperature, the authors improved the line-edge roughness (LER) of the 1:1 line-and-space and isolated space CDs by ∼40%. To understand how the PEB affected the resultant structures, the authors measured the hardness of cured resists with and without a PEB at various temperatures. Optimizing the PEB temperature of the non-CAR increased the resist contrast, annealing the resist and improving the LER. As such, their technique is capable of high resolutions on the order of 20 nm. The insights the authors gained from optimizing the PEB might be useful when fabricating next-generation masks.

  14. Reducing Line Edge Roughness of PS-b-PMMA pattern by inducing hydrogen bonding at the interface of the block copolymer microdomains

    NASA Astrophysics Data System (ADS)

    Lee, Kyu Seong; Han, Sung Hyun; Jang, Sangshin; Park, Jicheol; Kwak, Jongheon; Kim, Jin Kon

    Sharp interface between two blocks in block copolymer nano pattern is one of the important issues in industrial applications to nano-patterning. We utilized hydrogen bonding between N-(4-aminomethyl-benzyl)-4-hydroxymethyl-bezamide (BA) and urea (U) at the interface of polystyrene-block-poly(methyl methacrylate) copolymer (PS-PMMA). For this purpose, we first synthesized PS by ATRP, then the end group was converted to amino group. Next, it was reacted with BA, followed by reaction with 4-pentynoic acid, resulting in alkyne-terminated group (PS-U-BA-alkyne). Also, azide-terminated PMMA was prepared by anionic polymerization followed by end functionalization. Finally, by the azide-alkyne click reaction between PS-U-BA-alkyne and PMMA-azide, PS-U-BA-PMMA was synthesized. We prepared vertical oriented lamellar nanopatterns on pre-patterned wafers and investigated line edge roughness (LER) after removing PMMA block by dry etching process. We found that LER was reduced compared with PS-PMMA without hydrogen bonding.

  15. Talbot effect of grating with fractal rough edges

    NASA Astrophysics Data System (ADS)

    Teng, Shuyun; Cui, Yuwei; Li, Zhong

    2016-01-01

    Since the random edges of practically manufactured grating can be described by the self-affine fractal model, this paper investigates theoretically Fresnel diffraction of grating with rough edges on the basis of the self-affine fractal theory and discusses the variation of the Talbot image of grating with the rough parameters of edges. The amplitude gratings with different rough edges are produced with the help of the correlation function of the random distribution. Then, simulations of the diffraction intensity distributions of rough gratings are performed, and the modulation effect of speckles on Talbot image are shown. In order to explain the variation of the Talbot image of grating with rough edges, the theoretical analysis of the Talbot effect of grating with rough edges is given according to the statistic optics theory. The presented approximate analytic expression of the average diffraction intensity indicates the relationship between the diffraction and rough parameters of grating edges. The conclusions of this paper are useful for evaluating the Talbot image of practical grating.

  16. Experimental study of contact edge roughness on sub-100 nm various circular shapes

    NASA Astrophysics Data System (ADS)

    Lee, Tae Y.; Ihm, Dongchul; Kang, Hyo C.; Lee, Jum B.; Lee, Byoung H.; Chin, Soo B.; Cho, Do H.; Song, Chang L.

    2005-05-01

    The measurement of edge roughness has become a hot issue in the semiconductor industry. Especially the contact roughness is being more critical as design rule shrinks. Major vendors offer a variety of features to measure the edge roughness in their CD-SEMs. For the line and space patterns, features such as Line Edge Roughness (LER) and Line Width Roughness (LWR) are available in current CD-SEMs. However the features currently available in commercial CD-SEM cannot provide a proper solution in monitoring the contact roughness. We had introduced a new parameter R, measurement algorithm and definition of contact edge roughness to quantify CER and CSR in previous paper. The parameter, R could provide an alternative solution to monitor contact or island pattern roughness. In this paper, we investigated to assess optimum number of CD measurement (1-D) and fitting method for CER or CSR. The study was based on a circular contact shape. Some new ideas to quantify CER or CSR were also suggested with preliminary experimental results.

  17. Combined effect of edge roughness and phonon scattering on the electronic properties of ultra scaled graphene nano-ribbons

    NASA Astrophysics Data System (ADS)

    Akhoondali, Hossein; Goharrizi, Arash Yazdanpanah; Sharifi, Mohammad Javad

    2014-11-01

    The effect of optical and acoustic phonon-scattering in the presence of line-edge-roughness (LER) on the electronic properties of ultra-scaled armchair graphene nano-ribbons (AGNRs) is investigated. Non-equilibrium Green's function formalism (NEGF) is employed using a Hamiltonian formed from tight bonding model with consideration of first and third nearest neighbors. The combined effect of phonons and line edge roughness on the transmission, transport gap, and conductance are studied for different roughness strengths and AGNR lengths. Results show edge roughness slightly reduces the onset of optical phonon emission, acoustic phonons reduce off-state conductance and optical phonons reduce on-state conductance. In both cases, the degree and behavior of reduction is totally dependent on the intensity of edge roughness. Also, in the longer AGNRs with high edge roughness intensity, phonons increase the transport gap.

  18. Characteristics of surface roughness associated with leading edge ice accretion

    NASA Technical Reports Server (NTRS)

    Shin, Jaiwon

    1994-01-01

    Detailed size measurements of surface roughness associated with leading edge ice accretions are presented to provide information on characteristics of roughness and trends of roughness development with various icing parameters. Data was obtained from icing tests conducted in the Icing Research Tunnel (IRT) at NASA Lewis Research Center (LeRC) using a NACA 0012 airfoil. Measurements include diameters, heights, and spacing of roughness elements along with chordwise icing limits. Results confirm the existence of smooth and rough ice zones and that the boundary between the two zones (surface roughness transition region) moves upstream towards stagnation region with time. The height of roughness grows as the air temperature and the liquid water content increase, however, the airspeed has little effect on the roughness height. Results also show that the roughness in the surface roughness transition region grows during a very early stage of accretion but reaches a critical height and then remains fairly constant. Results also indicate that a uniformly distributed roughness model is only valid at a very initial stage of the ice accretion process.

  19. The effects of leading edge roughness on dynamic stall

    NASA Astrophysics Data System (ADS)

    Hrynuk, John

    2016-11-01

    Dynamic stall is a fundamental flow phenomenon that is commonly observed for insect flight and rotorcraft. Under certain conditions a leading edge vortex forms generating large but temporary lift forces. Historically, computations studying dynamic stall on airfoil shapes have struggled to predict this vortex formation time and separation point. Reduced order models and CFD have performed well when experiments have been performed to develop separation models, but this has limited the development of robust design tools. The current study looks at the effect of leading edge surface roughness on the formation of the Dynamic Stall Vortex (DSV). Roughness elements were applied to the leading edge of a NACA 0012 airfoil and PIV data of the vortex formation process was recorded. Measurements were taken at a Reynolds number of Re = 12,000 and baseline smooth NACA 0012 data was also recorded for comparison. Surface roughness elements, below the typical scale modeled by CFD, are shown to change DSV formation angle and location.

  20. Vortex ratchet induced by controlled edge roughness

    NASA Astrophysics Data System (ADS)

    Cerbu, D.; Gladilin, V. N.; Cuppens, J.; Fritzsche, J.; Tempere, J.; Devreese, J. T.; Moshchalkov, V. V.; Silhanek, A. V.; Van de Vondel, J.

    2013-06-01

    We demonstrate theoretically and experimentally the generation of rectified mean vortex displacement resulting from a controlled difference between the surface barriers at the opposite borders of a superconducting strip. Our investigation focuses on Al superconducting strips where, in one of the two sample borders, a saw tooth-like array of micro-indentations has been imprinted. The origin of the vortex ratchet effect is based on the fact that (i) the onset of vortex motion is mainly governed by the entrance/nucleation of vortices and (ii) the current lines bunching produced by the indentations facilitates the entrance/nucleation of vortices. Only for one current direction the indentations are positioned at the side of vortex entry and the onset of the resistive regime is lowered compared to the opposite current direction. This investigation points to the relevance of ubiquitous border effects typically neglected when interpreting vortex ratchet measurements on samples with arrays of local asymmetric pinning sites.

  1. Anisotropy and edge roughness scattering in the thermal conductivity of graphene nanoribbons

    NASA Astrophysics Data System (ADS)

    Aksamija, Zlatan; Knezevic, Irena

    2011-03-01

    We present a calculation of the thermal conductivity of graphene nanoribbons, based on solving the Boltzmann transport equation with the full phonon dispersions, a momentum-dependent model for edge roughness scattering, as well as three-phonon and isotope scattering. The interplay between strong edge roughness scattering and the anisotropy of the phonon dispersions results in thermal conduction that strongly depends on the chiral angle of the nanoribbon. A minimum occurs in the armchair direction and a maximum is attained in zig-zag nanoribbons. We also show that both the thermal conductivity and the amount of armchair/zig-zag anisotropy depend strongly on the width of the nanoribbon and the rms height of the edge roughness, with smallest and most anisotropic thermal conductivities occuring in narrow GNRs with rough edges. We conclude that physical width of the nanoribbon and the rms roughness of its line edges can be used along with angular direction as parameters to tailor the value of the thermal conductivity. This work has been supported by the Computing Innovation Fellows Project (NSF award No. 0937060 to the Computing Research Association, sub-award CIF-146 to the University of Wisconsin) and by the AFOSR YIP program (award No. FA9550-09-1-0230).

  2. Roughness Effects on the Formation of a Leading Edge Vortex

    NASA Astrophysics Data System (ADS)

    Elliott, Cassidy; Lang, Amy; Wahidi, Redha; Wilroy, Jacob

    2016-11-01

    Microscopic scales cover the wings of Monarch butterflies, creating a patterned surface. This patterning is an important natural flow control mechanism that is thought to delay the growth of the leading edge vortex (LEV) produced by the flapping motion of a wing. The increased skin friction caused by the scales leads to a weaker LEV being shed into the butterfly's wake, lessening drag and increasing flight efficiency. To test this theory, a plate of random roughness was designed in SolidWorks and printed on the Objet 30 Pro 3D printer. A 2x3x5 cubic foot tow tank was used to test the rough plate at Reynold's numbers of 1500, 3000, and 6000 (velocities of 8, 16, and 32 mm/s) at an angle of attack of 45 degrees. Particle Image Velocimetry (PIV) captured images of the LEV generated by the plate when towed upwards through the particle-seeded flow. Codes written in MatLab were used to automatically track and determine the strength of the LEV. Circulation values for the randomly-rough plate were then compared to the same values generated in a previous experiment that used a smooth plate and a grooved plate to determine the effect of the patterning on vortex development. Funding provided by NSF REU site Grant EEC 1358991 and CBET 1628600.

  3. What is the critical height of leading edge roughness for aerodynamics?

    NASA Astrophysics Data System (ADS)

    Bak, Christian; Gaunaa, Mac; Olsen, Anders S.; Kruse, Emil K.

    2016-09-01

    In this paper the critical leading edge roughness height is analyzed in two cases: 1) leading edge roughness influencing the lift-drag ratio and 2) leading edge roughness influencing the maximum lift. The analysis was based on wind tunnel measurements on the airfoils NACA0015, Risoe-B1-18 and Risoe-C2-18 and at three different Reynolds numbers with two different leading edge roughness tape heights. Firstly, an analysis of the momentum thickness as function of Reynolds number was carried out based on the boundary layer theory by Thwaites. Secondly, the wind tunnel measurements combined with panel code predictions of the boundary layer momentum thickness created the basis for determining the impact of roughness on the aerodynamic performance. The critical heights were related to the Reynolds numbers and thereby the size of the wind turbines.

  4. Spontaneous edge current in a small chiral superconductor with a rough surface

    NASA Astrophysics Data System (ADS)

    Suzuki, Shu-Ichiro; Asano, Yasuhiro

    2016-10-01

    We study theoretically the spontaneous edge current in a small chiral superconductor with surface roughness. We obtained self-consistent solutions of the pair potential and the vector potential by solving the quasiclassical Eilenberger equation and the Maxwell equation simultaneously. We then employed them to calculate numerically the spatial distribution of the chiral edge current in a small superconductor. The characteristic behavior of the spontaneous edge current depends strongly on the symmetries of the order parameters such as chiral p -, chiral d -, and chiral f -wave pairing. The edge current is robust under the surface roughness in the chiral p - and chiral d -wave superconductors. In the chiral d -wave case, the surface roughness tends to flip the direction of the chiral current. On the other hand, the edge current in a chiral f -wave superconductor is fragile when there is surface roughness. We also discuss the temperature dependence of a spontaneous magnetization, which is a measurable value in standard experiments.

  5. On universality of scaling law describing roughness of triple line.

    PubMed

    Bormashenko, Edward; Musin, Albina; Whyman, Gene; Barkay, Zahava; Zinigrad, Michael

    2015-01-01

    The fine structure of the three-phase (triple) line was studied for different liquids, various topographies of micro-rough substrates and various wetting regimes. Wetting of porous and pillar-based micro-scaled polymer surfaces was investigated. The triple line was visualized with the environmental scanning electron microscope and scanning electron microscope for the "frozen" triple lines. The value of the roughness exponent ζ for water (ice)/rough polymer systems was located within 0.55-0.63. For epoxy glue/rough polymer systems somewhat lower values of the exponent, 0.42 < ζ < 0.54, were established. The obtained values of ζ were close for the Cassie and Wenzel wetting regimes, different liquids, and different substrates' topographies. Thus, the above values of the exponent are to a great extent universal. The switch of the exponent, when the roughness size approaches to the correlation length of the defects, is also universal.

  6. Comparative study of line roughness metrics of chemically amplified and inorganic resists for extreme ultraviolet

    NASA Astrophysics Data System (ADS)

    Fallica, Roberto; Buitrago, Elizabeth; Ekinci, Yasin

    2016-07-01

    We present a comprehensive comparative study of the roughness metrics of different resists. Dense line/space of polymethyl methacrylate, hydrogen silsesquioxane, a metal oxide-based resist, and different chemically amplified resists (CARs) have been patterned by extreme ultraviolet interference lithography. All three line width roughness (LWR) metrics: the root-mean-square (r.m.s.) roughness value σLWR, the correlation length ξ, and the roughness exponent α, were extracted by metrological analysis of top-down SEM images. We found that all metrics are required to fully describe the overall roughness of each resist. Our measurements indicate that in fact, a few of the state-of-the-art resists tested here can meet the International Technology Roadmap for Semiconductors requirements for σLWR. The correlation length ξ was also found to be considerably higher in polymer-based materials in comparison to nonpolymers. Finally, the roughness exponent α, interpreted using the concept of fractal geometry, was found to be mainly affected by acid diffusion in CARs, where it produces line edges with a higher complexity than in non-CAR resists. These results indicate that the different resists platforms show very different LWR metrics and roughness is not manifested only in the σLWR but in all parameters. Therefore, all roughness metrics should be taken into account when comparing the performance among different resists since they ultimately have a substantial impact on device performance.

  7. Comparative study of line roughness metrics of chemically amplified and inorganic resists for EUV

    NASA Astrophysics Data System (ADS)

    Fallica, Roberto; Buitrago, Elizabeth; Ekinci, Yasin

    2016-03-01

    We present a comprehensive study of the roughness metrics of different resists. Dense line/space (L/S) images of polymethyl methacrylate (PMMA), hydrogen silsesquioxane (HSQ), different chemically amplified resists (CARs), and metal oxide based resists have been patterned by extreme ultraviolet interference lithography (EUV-IL). The three line width roughness metrics: r.m.s. value σLWR, correlation length ξ and roughness exponent α, were measured by metrological analysis of top down SEM images and compared for the different resists imaged here. It was found, that all metrics are required to fully describe the roughness of each resist. Our measurements indicate that few of the state-of-the- art resists tested here can meet the International Technology Roadmap for Semiconductors (ITRS) requirements for σLWR. The correlation length ξ has been found to be considerably higher in polymer-based materials in comparison to non-polymers. The roughness exponent α, interpreted using the concept of fractal geometry, is mainly affected by acid diffusion in CARs where it produces line edges with a higher complexity than in non-CAR resists. These results indicate that different resists platforms show very different LWR resist metrics and roughness is not only manifested in the σLWR but in all parameters. Therefore, all roughness metrics should be taken into account in the performance comparison of the resist, since they can have a substantial impact on the device performance.

  8. Line width roughness accuracy analysis during pattern transfer in self-aligned quadruple patterning process

    NASA Astrophysics Data System (ADS)

    Lorusso, Gian Francesco; Inoue, Osamu; Ohashi, Takeyoshi; Altamirano Sanchez, Efrain; Constantoudis, Vassilios; Koshihara, Shunsuke

    2016-03-01

    Line edge roughness (LER) and line width roughness (LWR) are analyzed during pattern transfer in a self-aligned quadruple patterning (SAQP) process. This patterning process leads to a final pitch of 22.5nm, relevant for N7/N5 technologies. Measurements performed by CD SEM (Critical Dimension Scanning Electron Microscope) using different settings in terms of averaging, field of view, and pixel size are compared with reference metrology performed by planar TEM and three-Dimensional Atomic Force Microscope (3D AFM) for each patterning process step in order to investigate the optimal condition for an in-line LWR characterization. Pattern wiggling is als0 quantitatively analyzed during LER/LWR transfer in the SAQP process.

  9. Computing of the Theoretical Value of Roughness Parameter Rz when Turning with Helical Cutting Edge

    NASA Astrophysics Data System (ADS)

    Šajgalík, Michal; Martikáň, Anton; Czán, Andrej; Pile, Jozef; Holubják, Jozef; Mrázik, Jozef

    2016-12-01

    This article describes process of computing and identifying of the value of roughness parameter Rz deduced from basic kinematic and geometric characteristics of turning technology of machining with tool with helical cutting edge. The final mathematical formula is deduced from graphic sketch of turning process and consequently identified using all the known geometric and kinematic parameters. This formula can be used to theoretic evaluation of geometric and cutting parameters influence on the quality of machined surface determined by roughness characteristic of theoretic parameter Rz.

  10. Uniform line integral representation of edge-diffracted fields.

    PubMed

    Umul, Yusuf Z

    2008-01-01

    A uniform line integral representation is derived for edge-diffracted fields by using the modified theory of physical optics and uniform asymptotic evaluation methods. The method is applied to the problem of diffraction of plane waves by a semi-infinite edge, which creates tip-diffracted fields with edge-diffracted waves. The uniform diffracted fields are plotted and examined numerically.

  11. Direct Numerical Simulation of an Airfoil with Sand Grain Roughness on the Leading Edge

    NASA Technical Reports Server (NTRS)

    Ribeiro, Andre F. P.; Casalino, Damiano; Fares, Ehab; Choudhari, Meelan

    2016-01-01

    As part of a computational study of acoustic radiation due to the passage of turbulent boundary layer eddies over the trailing edge of an airfoil, the Lattice-Boltzmann method is used to perform direct numerical simulations of compressible, low Mach number flow past an NACA 0012 airfoil at zero degrees angle of attack. The chord Reynolds number of approximately 0.657 million models one of the test conditions from a previous experiment by Brooks, Pope, and Marcolini at NASA Langley Research Center. A unique feature of these simulations involves direct modeling of the sand grain roughness on the leading edge, which was used in the abovementioned experiment to trip the boundary layer to fully turbulent flow. This report documents the findings of preliminary, proof-of-concept simulations based on a narrow spanwise domain and a limited time interval. The inclusion of fully-resolved leading edge roughness in this simulation leads to significantly earlier transition than that in the absence of any roughness. The simulation data is used in conjunction with both the Ffowcs Williams-Hawkings acoustic analogy and a semi-analytical model by Roger and Moreau to predict the farfield noise. The encouraging agreement between the computed noise spectrum and that measured in the experiment indicates the potential payoff from a full-fledged numerical investigation based on the current approach. Analysis of the computed data is used to identify the required improvements to the preliminary simulations described herein.

  12. Spin-dependent electron transport in a Rashba quantum wire with rough edges

    NASA Astrophysics Data System (ADS)

    Xiao, X. B.; Li, H. L.; Zhou, G. H.; Liu, N. H.

    2012-09-01

    We investigate theoretically the spin-dependent electron transport in a Rashba quantum wire with rough edges. The charge and spin conductances are calculated as function of the electron energy and wire length by adopting the spin-resolved lattice Green function method. For a single disordered Rashba wire, it is found that the charge conductance quantization is destroyed by the edge disorder. However, a nonzero spin conductance can be generated and its amplitude can be manipulated by varying the wire length, which is attributed to the broken structure symmetries and the spin-dependent quantum interference induced by the rough boundaries. For a large ensemble of disordered Rashba wires, the average charge conductance decreases monotonically, however, the average spin conductance increases to a maximum value and then decreases, with increasing wire length. Further study shows that the influence of the rough edges on the charge and spin conductances can be eliminated by applying a perpendicular magnetic field to the wire. In addition, a very large magnitude of the spin conductance can be achieved when the electron energy lies between the two thresholds of each pair of subbands. These findings may not only benefit to further apprehend the transport properties of the Rashba low-dimensional systems but also provide some theoretical instructions to the application of spintronics devices.

  13. A New Method for Line Width Roughness Mitigation

    NASA Astrophysics Data System (ADS)

    Mayya, K. Subramanya; Yool, Kang; Kim, Hochul; Cho, Han-Ku

    2011-06-01

    Demands of the continuous downscaling of device size impose stringent requirements on the RLS trade-off (R: resolution, L: line width roughness and S: sensitivity). Among the above, line width roughness (LWR) has to be controlled below 10% of critical dimensions (CD). While significant improvement in R&S was achieved, LWR has been relatively high for extreme ultra-violet lithography resists. Herein, we provide a new method for LWR mitigation that overcomes several shortcomings of previously known methods. Our new method is based on a double development method wherein, a polymeric solution in developer is coated on to the patterned surface. The wafer is then subjected to the standard development step during which LWR improvement is affected. In this paper we discuss the hypothesis of our method and provide relevant data to understand the conditions under which LWR improvement is observed. Effect of polymer/developer concentration ratio, solid content and bake temperatures will be discussed. Also, our method will be compared with currently available methods for LWR improvement on pattern transfer.

  14. Effects of Roof-Edge Roughness on Air Temperature and Pollutant Concentration in Urban Canyons

    NASA Astrophysics Data System (ADS)

    Aliabadi, Amir A.; Krayenhoff, E. Scott; Nazarian, Negin; Chew, Lup Wai; Armstrong, Peter R.; Afshari, Afshin; Norford, Leslie K.

    2017-08-01

    The influence of roof-edge roughness elements on airflow, heat transfer, and street-level pollutant transport inside and above a two-dimensional urban canyon is analyzed using an urban energy balance model coupled to a large-eddy simulation model. Simulations are performed for cold (early morning) and hot (mid afternoon) periods during the hottest month of the year (August) for the climate of Abu Dhabi, United Arab Emirates. The analysis suggests that early in the morning, and when the tallest roughness elements are implemented, the temperature above the street level increases on average by 0.5 K, while the pollutant concentration decreases by 2% of the street-level concentration. For the same conditions in mid afternoon, the temperature decreases conservatively by 1 K, while the pollutant concentration increases by 7% of the street-level concentration. As a passive or active architectural solution, the roof roughness element shows promise for improving thermal comfort and air quality in the canyon for specific times, but this should be further verified experimentally. The results also warrant a closer look at the effects of mid-range roughness elements in the urban morphology on atmospheric dynamics so as to improve parametrizations in mesoscale modelling.

  15. A numerical and experimental study of the effects of dynamic roughness on laminar leading edge separation

    NASA Astrophysics Data System (ADS)

    Gall, Peter D.

    The aircraft industry, as a whole, has been deeply concerned with improving the aerodynamic efficiency of current and future flight vehicles, particularly in the commercial and military markets. However, of particular interest to the field of aerodynamics is the elusive concept of a workable flow control mechanism. Effective flow control is a concept which if properly applied can increase aerodynamic efficiency. Various concepts and ideas to obtain successful flow control have been studied in an attempt to reap these rewards. Some examples include boundary layer blowing (steady and periodic), suction, and compliant walls for laminar flow control. The overall goal of flow control is to increase performance by increasing lift, reducing drag, and delaying or eliminating leading edge separation. The specific objectives of flow control are to (1) delay or eliminate flow separation, (2) delay boundary layer transition, and (3) and reduce skin friction drag. The purpose of this research is to investigate dynamic roughness as a novel method of flow control technology for external boundary layer flows. As opposed to standard surface roughness, dynamic roughness incorporates small time dependent perturbations to the surface of the airfoil. These surface perturbations are actual humps and/or ridges on the surface of the airfoil that are on the scale of the laminar boundary, and oscillate with an unsteady motion. Research has shown that this can provide a means to modify the instantaneous and mean velocity profile near the wall and favorably control the existing state of the boundary layer. Several flow control parameters were studied including dynamic roughness frequency, amplitude, and geometry. The results of this study have shown, both numerically and experimentally, that dynamic roughness can provide an effective means for eliminating both a short and long laminar separation bubble and possibly prove a viable alternative in effective flow control, hence reaping some of

  16. Edge Effects in Line Intersect Sampling With

    Treesearch

    David L. R. Affleck; Timothy G. Gregoire; Harry T. Valentine

    2005-01-01

    Transects consisting of multiple, connected segments with a prescribed configuration are commonly used in ecological applications of line intersect sampling. The transect configuration has implications for the probability with which population elements are selected and for how the selection probabilities can be modified by the boundary of the tract being sampled. As...

  17. TEMPERATURE DEPENDENCE OF LINE STRUCTURE OF CADMIUM SULFIDE EDGE EMISSION

    DTIC Science & Technology

    The temperature dependence of the line structure in Cds edge emission stimulated by UV light was investigated from 4.2 K to 367 K. The spectral... dependence of the primary line groups is a linear function of temperature above 220 K with coefficients of change of 1.27 and 1.8 Angstroms degree K for the...lines observed. Below 220 K the dependence departs from linearity and approaches its limiting value more rapidly with decreasing temperature

  18. Line width roughness control and pattern collapse solutions for EUV patterning

    NASA Astrophysics Data System (ADS)

    Petrillo, Karen; Huang, George; Ashworth, Dominic; Georger, Jacque; Ren, Liping; Cho, K. Y.; Montgomery, Warren; Wurm, Stefan; Kawakami, Shinichiro; Dunn, Shannon; Ko, Akiteryu

    2011-04-01

    Line width roughness (LWR) control is a critical issue in extreme ultraviolet lithography (EUVL). The difficulty of controlling LWR and the need to minimize it have grown as the sensitivity of materials and resolution in the resist patterning process has improved. Another critical feature that has become difficult to control in EUVL and 22nm half-pitch systems is pattern collapse. The increase of aspect ratio that comes from further scaling promotes the onset of pattern collapse. Both pattern collapse and LWR are easily observed in EUVL and leading-edge ArF immersion lithography. This paper will demonstrate recent gains in LWR control in leading EUV films using track-based processes, etch-based improvements, and the results of combined techniques. Also the use of a newly developed EUV-specific FIRM™ rinse chemistry to reduce pattern collapse will be discussed along with future development activities and industry requirements for both LWR and pattern collapse.

  19. Edge determination for polycrystalline silicon lines on gate oxide

    NASA Astrophysics Data System (ADS)

    Villarrubia, John S.; Vladar, Andras E.; Lowney, Jeremiah R.; Postek, Michael T., Jr.

    2001-08-01

    In a scanning electron microscope (SEM) top-down secondary electron image, areas within a few tens of nanometers of the line edges are characteristically brighter than the rest of the image. In general, the shape of the secondary electron signal within such edge regions depends upon the energy and spatial distribution of the electron beam and the sample composition, and it is sensitive to small variations in sample geometry. Assigning edge shape and position is done by finding a model sample that is calculated, on the basis of a mathematical model of the instrument-sample interaction, to produce an image equal to the one actually observed. Edge locations, and consequently line widths, are then assigned based upon this model sample. In previous years we have applied this strategy to lines with geometry constrained by preferential etching of single crystal silicon. With this study we test the procedure on polycrystalline silicon lines. Polycrystalline silicon lines fabricated according to usual industrial processes represent a commercially interesting albeit technically more challenging application of this method. With the sample geometry less constrained a priori, a larger set of possible sample geometries must be modeled and tested for a match to the observed line scan, and the possibility of encountering multiple acceptable matches is increased. For this study we have implemented a data analysis procedure that matches measured image line scans to a precomputed library of sample shapes and their corresponding line scans. Linewidth test patterns containing both isolated and dense lines separated form the underlying silicon substrate by a thin gate oxide have been fabricated. Line scans from test pattern images have been fitted to the library of modeled shapes.

  20. Motion of a granular particle on a rough line

    NASA Astrophysics Data System (ADS)

    Marini Bettolo Marconi, U.; Conti, M.; Vulpiani, A.

    2000-09-01

    We discuss a new model of ideal granular gas consisting of a particle bouncing inelastically along a rough inclined plane. Assuming a velocity-dependent inelastic interaction between the surface and the falling object we study the dynamical phase diagram which consists of three different phases: an accelerated motion, a stopping phase and a phase where the velocity fluctuates about a constant value. We analyze the statistical properties of the steady velocity regime and find that the velocity distribution is characterized by power law tails with a nonuniversal exponent β which depends on the nature of the surface. An explanation for this phenomenon is presented and its relation with random multiplicative processes expounded.

  1. Real-time value optimization of edging and trimming operations for rough, green hardwood lumber

    Treesearch

    Daniel L. Schmoldt; Hang Song; Philip A. Araman

    2001-01-01

    For edging/trimming operations in hardwood sawmills, an operator examines both sides—or just the waney-edged side—of each board, and makes a quick assessment of grade potential. The operator then decides where to edge and/or trim the board to achieve the intended grade and, presumably, maximum value. However, human operators can only achieve lumber values that are 62-...

  2. High-Speed Edge-Detecting Line Scan Smart Camera

    NASA Technical Reports Server (NTRS)

    Prokop, Norman F.

    2012-01-01

    A high-speed edge-detecting line scan smart camera was developed. The camera is designed to operate as a component in a NASA Glenn Research Center developed inlet shock detection system. The inlet shock is detected by projecting a laser sheet through the airflow. The shock within the airflow is the densest part and refracts the laser sheet the most in its vicinity, leaving a dark spot or shadowgraph. These spots show up as a dip or negative peak within the pixel intensity profile of an image of the projected laser sheet. The smart camera acquires and processes in real-time the linear image containing the shock shadowgraph and outputting the shock location. Previously a high-speed camera and personal computer would perform the image capture and processing to determine the shock location. This innovation consists of a linear image sensor, analog signal processing circuit, and a digital circuit that provides a numerical digital output of the shock or negative edge location. The smart camera is capable of capturing and processing linear images at over 1,000 frames per second. The edges are identified as numeric pixel values within the linear array of pixels, and the edge location information can be sent out from the circuit in a variety of ways, such as by using a microcontroller and onboard or external digital interface to include serial data such as RS-232/485, USB, Ethernet, or CAN BUS; parallel digital data; or an analog signal. The smart camera system can be integrated into a small package with a relatively small number of parts, reducing size and increasing reliability over the previous imaging system..

  3. Comparison of glue-line quality between gang edging and straight-line ripping

    Treesearch

    Charles J. Gatchell; James R. Olson; James R. Olson

    1986-01-01

    Gang edging with a dip-chain fed gang ripsaw produces gluing surfaces equal to those from a straight-line ripsaw in yellow-poplar (Liriodendron tulipifera) and red oak (Quercus rubra). Special care in gluing red oak was needed to get shear strengths equal to solid wood values. However, the strength comparisons between sawing methods showed no differences between gang...

  4. Fabrication of Cu nanowires along atomic step edge lines on Si(1 1 1) substrates

    NASA Astrophysics Data System (ADS)

    Tokuda, Norio; Watanabe, Hidenobu; Hojo, Daisuke; Yamasaki, Satoshi; Miki, Kazushi; Yamabe, Kikuo

    2004-10-01

    We have succeeded in the fabrication of high-aspect-ratio (length to width) Cu nanowires along atomic step edge lines on Si(1 1 1) substrates. The fabrication procedure consisted of two wet process steps: (1) flattening of the surface roughness to an atomic level by immersing Si(1 1 1) wafers in ultralow-dissolved-oxygen water (LOW), and (2) Cu nanowire formation by immersion in LOW containing 10 ppm Cu ions for 1 s at room temperature. On the other hand, no Cu nanowires were formed on the Si(1 1 1) surfaces when the dissolved oxygen content was 8 ppm in alkaline solution during the Cu deposition stage, even though the Si etching with OH - was enhanced. We consider that it is due to the decrease in reduced Cu atom density by the existence of the dissolved oxygen as superoxide anion radicals.

  5. In-line digital holography with double knife edge

    NASA Astrophysics Data System (ADS)

    Ramirez, Claudio; Iemmi, Claudio; Campos, Juan

    2015-06-01

    We study and test a new technique for in-line digital holography which avoids the formation of the conjugate images. Inline digital holography is based in a common path configuration. In this case, the hologram is produced by the interference between the reference wave front and the diffracted wave front by an almost transparent object. Twin images are obtained with obscured rings that difficult the determination of the best focusing plane. To avoid the conjugated image, the information of the magnitude and phase of the wave front are needed. In a recent work a new in-line digital holography technique was proposed. In this method the object is illuminated with a collimated wave front. A plane, close to the particles distribution is imaged onto a CCD by means of a convergent lens and at the same time, a knife edge is placed in the focal plane of the lens in order to block half of spatial frequency spectrum. In this way, by means of a numerical processing performed on the Fourier plane, it is possible to eliminate one of the components (real or conjugate) of the reconstructed images nevertheless it is observed a tiny deformation of the resulting hologram image. To compensate this effect, we propose a new configuration in which we implement the knife edge technique on both parts of the spectrum at the same time. Finally in the computer, we process the holograms to build one complete without deformation. This hologram is used to recover the wave front at different planes without the influence of the conjugate image.

  6. Reaction of sorghum lines to zonate leaf spot and rough leaf spot

    USDA-ARS?s Scientific Manuscript database

    Abundant, frequent rains, along with humid and cloudy conditions during the early part of the 2015 growing season, provided conducive conditions for an unusually severe outbreak of zonate leaf spot and rough leaf spot in a block of sorghum lines at the Texas A&M AgriLife Research Farm, Burleson Coun...

  7. Line Edge Detection and Characterization in SEM Images using Wavelets

    SciTech Connect

    Sun, W; Romagnoli, J A; Tringe, J W; L?tant, S E; Stroeve, P; Palazoglu, A

    2008-10-07

    Edge characterization has become increasingly important in nanotechnology due to the growing demand for precise nanoscale structure fabrication and assembly. Edge detection is often performed by thresholding the spatial information of a top-down image obtained by Scanning Electron Microscopy (SEM) or other surface characterization techniques. Results are highly dependent on an arbitrary threshold value, which makes it difficult to reveal the nature of the real surface and to compare results among images. In this paper, we present an alternative edge boundary detection technique based on the wavelet framework. Our results indicate that the method facilitates nano-scale edge detection and characterization, by providing a systematic threshold determination step.

  8. Critical dimension uniformity and contact edge roughness in extreme ultraviolet lithography: effect of photoacid generator, sensitizer and quencher

    NASA Astrophysics Data System (ADS)

    Kuppuswamy, Vijaya-Kumar Murugesan; Constantoudis, Vassilios; Gogolides, Evangelos; Pret, Alessandro Vaglio; Gronheid, Roel

    2013-04-01

    One of the main challenges for developing extreme ultraviolet resists is to satisfy critical dimension uniformity (CDU) and sidewall roughness of contacts to the allowable limit. To this end, further understanding of the effects of resist ingredients on CDU and contact edge roughness (CER) is required. We investigate the effects of a photoacid generator (PAG), sensitizer and quencher concentrations on the CDU and CER. We find that the dependencies of CDU on sensitizer and quencher are dominated by photon shot noise (PSN) effects whereas a more complicated interplay between PSN and PAG distribution statistics should be considered in the dependence of CDU on PAG concentration. The estimated CER parameters [root mean square (RMS) value and correlation length ξ] exhibit a merging trend when plotted against the final critical dimension (CD). In addition, RMS value increases with exposure dose and PAG loading contrary to shot noise expectations. Power spectrum analysis reveals the dominant contribution of low-frequency undulations to CER, which is attributed to the enhanced interaction along specific directions between the aerial image and/or acid kinetics of nearby contacts. This inter-contact effect is further intensified with CD for fixed pitch and may explain the observed CER behavior.

  9. Effect of Wall Temperature on Roughness Induced Attachment-Line Transition

    NASA Technical Reports Server (NTRS)

    Dietz, Anthony; Coleman, Colin; Laub, Jim; Poll, D. I. A.; Nixon, David (Technical Monitor)

    1999-01-01

    An experiment on a cooled swept cylinder in a low-disturbance Mach 1.6 wind tunnel is described. The flow attachment line is disturbed by trip wires of varying size and the laminar/turbulent state of the downstream boundary layer is determined with a hot wire. The results demonstrate that although cooling the wall increases the stability of the boundary layer, it promotes roughness induced transition. Analysis of the data suggests that the attachment- line Reynolds number can account for the effect of wall cooling if the viscosity is evaluated at a particular reference temperature.

  10. Line-edge quality optimization of electron beam resist for high-throughput character projection exposure utilizing atomic force microscope analysis

    NASA Astrophysics Data System (ADS)

    Ikeno, Rimon; Mita, Yoshio; Asada, Kunihiro

    2017-04-01

    High-throughput electron-beam lithography (EBL) by character projection (CP) and variable-shaped beam (VSB) methods is a promising technique for low-to-medium volume device fabrication with regularly arranged layouts, such as standard-cell logics and memory arrays. However, non-VLSI applications like MEMS and MOEMS may not fully utilize the benefits of CP method due to their wide variety of layout figures including curved and oblique edges. In addition, the stepwise shapes that appear on such irregular edges by VSB exposure often result in intolerable edge roughness, which may degrade performances of the fabricated devices. In our former study, we proposed a general EBL methodology for such applications utilizing a combination of CP and VSB methods, and demonstrated its capabilities in electron beam (EB) shot reduction and edge-quality improvement by using a leading-edge EB exposure tool, ADVANTEST F7000S-VD02, and high-resolution Hydrogen Silsesquioxane resist. Both scanning electron microscope and atomic force microscope observations were used to analyze quality of the resist edge profiles to determine the influence of the control parameters used in the exposure-data preparation process. In this study, we carried out detailed analysis of the captured edge profiles utilizing Fourier analysis, and successfully distinguish the systematic undulation by the exposed CP character profiles from random roughness components. Such capability of precise edge-roughness analysis is useful to our EBL methodology to maintain both the line-edge quality and the exposure throughput by optimizing the control parameters in the layout data conversion.

  11. Numerical and experimental study on the ability of dynamic roughness to alter the development of a leading edge vortex

    NASA Astrophysics Data System (ADS)

    Griffin, Christopher D.

    Dynamic stall is an unsteady aerodynamic phenomenon garnering much research interest because it occurs in a variety of applications. For example, dynamic stall is known to occur on helicopter rotor blades, wind turbines, high maneuvering military aircraft, and flapping wings. Dynamic stall occurs when an aerodynamic lifting device, such as an airfoil, wing, or turbomachine blade, undergoes a rapid pitching motion. It also occurs on lifting devices that are impulsively started at high angles of attack. Dynamic stall can "delay" aerodynamic stall to angles of attack that are significantly beyond the static stall angle of attack. During dynamic stall a large leading edge vortex (LEV) is formed, which creates greater fluid acceleration over the wing or airfoil, thus sustaining lift. As this vortex is shed downstream stall eventually occurs and there is an abrupt increase in drag and a large shift in pitching moment. Research has been performed to better understand the mechanisms occurring during dynamic stall in an effort to find ways to best take advantage of the increased lift associated with dynamic stall, but avoid the downfalls that occur once stall is initiated. Few attempts have been made to alter the LEV, and these attempts have used methods associated with laminar boundary layer separation control. Although these methods have shown promise, they suffer from the drawback that they exhaust more energy than is gained by flow control, while also only being effective at certain flight regimes. The research described herein documents the first study on the ability of dynamic roughness to alter the LEV encountered on a rapidly pitching airfoil. Both numerical and experimental studies were performed, including two-dimensional and three-dimensional computational fluid dynamics (CFD) simulations as well as stereo and planar particle image velocimetry (PIV) experiments. Evidence for the ability of small scale dynamic roughness to alter the development of the LEV was

  12. Effects of vacuum ultraviolet photons, ion energy and substrate temperature on line width roughness and RMS surface roughness of patterned 193 nm photoresist

    NASA Astrophysics Data System (ADS)

    Titus, M. J.; Graves, D. B.; Yamaguchi, Y.; Hudson, E. A.

    2011-03-01

    We present a comparison of patterned 193 nm photoresist (PR) line width roughness (LWR) of samples processed in a well characterized argon (Ar) inductively coupled plasma (ICP) system to RMS surface roughness and bulk chemical modification of blanket 193 nm PR samples used as control samples. In the ICP system, patterned and blanket PR samples are irradiated with Ar vacuum ultraviolet photons (VUV) and Ar ions while sample temperature, photon flux, ion flux and ion energy are controlled and measured. The resulting chemical modifications to bulk 193 nm PR (blanket) and surface roughness are analysed with Fourier transform infrared spectroscopy and atomic force microscopy (AFM). LWR of patterned samples are measured with scanning electron microscopy and blanket portions of the patterned PRs are measured with AFM. We demonstrate that with no RF-bias applied to the substrate the LWR of 193 nm PR tends to smooth and correlates with the smoothing of the RMS surface roughness. However, both LWR and RMS surface roughness increases with simultaneous high-energy (>=70 eV) ion bombardment and VUV-irradiation and is a function of exposure time. Both high- and low-frequency LWR correlate well with the RMS surface roughness of the patterned and blanket 193 nm PR samples. LWR, however, does not increase with temperatures ranging from 20 to 80 °C, in contrast to the RMS surface roughness which increases monotonically with temperature. It is unclear why LWR remains independent of temperature over this range. However, the fact that blanket roughness and LWR on patterned samples, both scale similarly with VUV fluence and ion energy suggests a similar mechanism is responsible for both types of surface morphology modifications.

  13. Droplet spreading on rough surfaces: Tackling the contact line boundary condition

    NASA Astrophysics Data System (ADS)

    Chamakos, Nikolaos T.; Kavousanakis, Michail E.; Boudouvis, Andreas G.; Papathanasiou, Athanasios G.

    2016-02-01

    The complicated dynamics of the contact line of a moving droplet on a solid substrate often hamper the efficient modeling of microfluidic systems. In particular, the selection of the effective boundary conditions, specifying the contact line motion, is a controversial issue since the microscopic physics that gives rise to this displacement is still unknown. Here, a sharp interface, continuum-level, novel modeling approach, accounting for liquid/solid micro-scale interactions assembled in a disjoining pressure term, is presented. By following a unified conception (the model applies both to the liquid/solid and the liquid/ambient interfaces), the friction forces at the contact line, as well as the dynamic contact angle are derived implicitly as a result of the disjoining pressure and viscous effects interplay in the vicinity of the substrate's intrinsic roughness. Previous hydrodynamic model limitations, of imposing the contact line boundary condition to an unknown number and reconfigurable contact lines, when modeling the spreading dynamics on textured substrates, are now overcome. The validity of our approach is tested against experimental data of a droplet impacting on a horizontal solid surface. The study of the early spreading stage on hierarchically structured and chemically patterned solid substrates reveal an inertial regime where the contact radius grows according to a universal power law, perfectly agreeing with recently published experimental findings.

  14. The optimization of edge and line detectors for forest image analysis

    Treesearch

    Zhiling Long; Joseph Picone; Victor A. Rudis

    2000-01-01

    Automated image analysis for forestry applications is becoming increasingly important with the rapid evolution of satellite and land-based remote imaging industries. Features derived from line information play a very important role in analyses of such images. Many edge and line detection algorithms have been proposed but few, if any, comprehensive studies exist that...

  15. Molecular Line Observations and Chemical Modelling of Edge Cloud 2

    NASA Astrophysics Data System (ADS)

    Ruffle, P.; Millar, T.; Roberts, H.; Lubowich, D.; Henkel, C.

    2009-01-01

    Edge Cloud 2 (EC2) is a large molecular cloud with one of the largest galactocentric distances known to exist in the Milky Way. We present observations of the cloud and use these to determine its physical characteristics. We calculate a gas temperature of 20 K and a density of n({H}2) ˜ 104 cm-3. Based on our CO maps, we estimate the mass of EC2 at around 104 Msun and continuum observations suggest a dust-to-gas mass ratio as low as 0.001. Chemical models have been developed to reproduce the abundances in EC2 and they indicate that: heavy element abundances may be reduced by a factor of five relative to the solar neighbourhood (similar to dwarf irregular galaxies and damped Lyman alpha systems); very low extinction (AV < 4 mag) due to a very low dust-to-gas ratio; an enhanced cosmic ray ionisation rate; and a higher UV field compared to local interstellar values. The reduced abundances may be attributed to the low level of star formation in this region and are probably also related to the continuing infall of low metallicity halo gas since the Milky Way formed. Finally, we note that shocks from the old supernova remnant GSH 138-01-94 may have determined the morphology and dynamics of EC2.

  16. Application of frequency domain line edge roughness characterization methodology in lithography

    NASA Astrophysics Data System (ADS)

    Sun, Lei; Wang, Wenhui; Beique, Genevieve; Wood, Obert; Kim, Ryoung-Han

    2015-03-01

    A frequency domain 3 sigma LER characterization methodology combining the standard deviation and power spectral density (PSD) methods is proposed. In the new method, the standard deviation is calculated in the frequency domain instead of the spatial domain as in the conventional method. The power spectrum of the LER is divided into three regions: low frequency (LF), middle frequency (MF) and high frequency (HF) regions. The frequency region definition is based on process visual comparisons. Three standard deviation numbers are used to characterize the LER in the three frequency regions. Pattern wiggling can be detected quantitatively with a wiggling factor which is also proposed in this paper.

  17. Reduction of line edge roughness (ler) in interference-like large field lithography

    NASA Astrophysics Data System (ADS)

    Benson, Richard Craddock

    The Mississippi Lime play is an important recent oil and gas development in the midcontinent of the United States. In April of 2007, Chesapeake Energy Corporation used horizontal drilling and multistage fracing to bring the Howell 1-33H well online. This well revitalized the Mississippi Lime play, expanding exploration with potential Mississippian reservoirs. The Mississippian section is a complex carbonate reservoir containing several distinct lithologies. An important Mississippian lithology known from outcrops in Arkansas and Missouri is tripolitic chert, or tripolite; a bleached, highly diagenetically altered, silica rock with high porosity, low density, and high permeability. Tripolite is an important reservoir target with the broader Mississippi dense lime play, but should not be confused with Mississippi Chat reservoirs found in Kansas or Oklahoma which commonly are described as cherty paleosols, chert breccia or conglomerates. Acoustic impedance of tripolite is quite low, leading to a characteristic strong negative amplitude anomaly in 3D seismic data (i.e., a lithology bright spot). This study presents techniques and results for seismic mapping of probable tripolite occurrences in the Wild Creek 3D seismic survey of Osage County, Oklahoma. Resolution estimates are also presented, along with preliminary reflection coefficient calculations indicating observed amplitude anomalies represent tripolite embedded in dense Mississippian limestone, a stratigraphic relationship in agreement with recent outcrop observations.

  18. Galactic Edge Clouds. I. Molecular Line Observations and Chemical Modeling of Edge Cloud 2

    NASA Astrophysics Data System (ADS)

    Ruffle, P. M. E.; Millar, T. J.; Roberts, H.; Lubowich, D. A.; Henkel, C.; Pasachoff, J. M.; Brammer, G.

    2007-12-01

    Edge Cloud 2 (EC2) is a molecular cloud, about 35 pc in size, with one of the largest galactocentric distances known to exist in the Milky Way. We present observations of a peak CO emission region in the cloud and use these to determine its physical characteristics. We calculate a gas temperature of 20 K and a density of n(H2)~104 cm-3. Based on our CO maps, we estimate the mass of EC2 at around 104 Msolar and continuum observations suggest a dust-to-gas mass ratio as low as 0.001. Chemical models have been developed to reproduce the abundances in EC2, and they indicate that heavy element abundances may be reduced by a factor of 5 relative to the solar neighborhood (similar to dwarf irregular galaxies and damped Lyα systems), very low extinction (AV<4 mag) due to a very low dust-to-gas mass ratio, an enhanced cosmic-ray ionization rate, and a higher UV field compared to local interstellar values. The reduced abundances may be attributed to the low level of star formation in this region and are probably also related to the continuing infall of primordial (or low-metallicity) halo gas since the Milky Way formed. Finally, we note that shocks from the old supernova remnant GSH 138-01-94 may have determined the morphology and dynamics of EC2.

  19. Molecular line observations and chemical modelling of galactic edge clouds

    NASA Astrophysics Data System (ADS)

    Ruffle, Paul; Millar, Tom; Roberts, Helen; Lubowich, Don; Henkel, Christian

    2008-10-01

    Edge Clouds 1 and 2 (EC1 and EC2) are large molecular clouds with the largest galactocentric distances known to exist in the Milky Way. We present observations of these clouds and use them to determine physical characteristics. For EC2 we calculate a gas temperature of 20 K and a density of n(H2) ~ 104 cm-3. Based on our CO maps, we estimate the mass of EC2 at around 104 M⊙, and continuum observations suggest a dust-to-gas mass ratio as low as 0.001. Chemical models have been developed to reproduce the abundances in EC2 and they indicate that: heavy element abundances may be reduced by a factor of five relative to the solar neighbourhood (similar to dwarf irregular galaxies and damped Lyman alpha systems); very low extinction (AV < 4 mag) due to a very low dust-to-gas ratio; an enhanced cosmic ray ionisation rate; and a higher UV field compared to local interstellar values. The reduced abundances may be attributed to the low level of star formation in this region and are probably also related to the continuing infall of low metallicity halo gas since the Milky Way formed. We find that shocks from an old supernova remnant may have determined the morphology and dynamics of EC2, including the recently discovered star clusters embedded in the northern and southern cores. However, compared to EC2, EC1 appears to be a chemically less varied environment. The apparent molecule-poor nature of EC1 demonstrates the characteristics of clouds that have not had the benefit of SN shocks to stimulate an active cloud chemistry and star formation.

  20. Effect of cutting edge radius on surface roughness in diamond tool turning of transparent MgAl2O4 spinel ceramic

    NASA Astrophysics Data System (ADS)

    Yue, Xiaobin; Xu, Min; Du, Wenhao; Chu, Chong

    2017-09-01

    Transparent magnesium aluminate spinel (MgAl2O4) ceramic is one of an important optical materials. However, due to its pronounced hardness and brittleness, the optical machining of this material is very difficult. Diamond turning has advantages over the grinding process in flexibility and material removal rate. However, there is a lack of research that could support the use of diamond turning technology in the machining of MgAl2O4 spinel ceramic. Using brittle-ductile transition theory of brittle material machining, this work provides critical information that may help to realize ductile-regime turning of MgAl2O4 spinel ceramic. A characterization method of determination the cutting edge radius is introduced here. Suitable diamond tools were measured for sharpness and then chosen from a large number of candidate tools. The influence of rounded cutting edges on surface roughness of the MgAl2O4 spinel ceramic is also investigated. These results indicate that surface quality of MgAl2O4 spinel is relate to the radius of diamond tool's cutting edge, cutting speed, and feed rate. Sharp diamond tools (small radius of cutting edge) facilitated ductile-regime turning of MgAl2O4 spinel and shows great potential to reduce surface roughness and produce smoother final surface.

  1. Virtual sensors for on-line wheel wear and part roughness measurement in the grinding process.

    PubMed

    Arriandiaga, Ander; Portillo, Eva; Sánchez, Jose A; Cabanes, Itziar; Pombo, Iñigo

    2014-05-19

    Grinding is an advanced machining process for the manufacturing of valuable complex and accurate parts for high added value sectors such as aerospace, wind generation, etc. Due to the extremely severe conditions inside grinding machines, critical process variables such as part surface finish or grinding wheel wear cannot be easily and cheaply measured on-line. In this paper a virtual sensor for on-line monitoring of those variables is presented. The sensor is based on the modelling ability of Artificial Neural Networks (ANNs) for stochastic and non-linear processes such as grinding; the selected architecture is the Layer-Recurrent neural network. The sensor makes use of the relation between the variables to be measured and power consumption in the wheel spindle, which can be easily measured. A sensor calibration methodology is presented, and the levels of error that can be expected are discussed. Validation of the new sensor is carried out by comparing the sensor's results with actual measurements carried out in an industrial grinding machine. Results show excellent estimation performance for both wheel wear and surface roughness. In the case of wheel wear, the absolute error is within the range of microns (average value 32 μm). In the case of surface finish, the absolute error is well below Ra 1 μm (average value 0.32 μm). The present approach can be easily generalized to other grinding operations.

  2. Virtual Sensors for On-line Wheel Wear and Part Roughness Measurement in the Grinding Process

    PubMed Central

    Arriandiaga, Ander; Portillo, Eva; Sánchez, Jose A.; Cabanes, Itziar; Pombo, Iñigo

    2014-01-01

    Grinding is an advanced machining process for the manufacturing of valuable complex and accurate parts for high added value sectors such as aerospace, wind generation, etc. Due to the extremely severe conditions inside grinding machines, critical process variables such as part surface finish or grinding wheel wear cannot be easily and cheaply measured on-line. In this paper a virtual sensor for on-line monitoring of those variables is presented. The sensor is based on the modelling ability of Artificial Neural Networks (ANNs) for stochastic and non-linear processes such as grinding; the selected architecture is the Layer-Recurrent neural network. The sensor makes use of the relation between the variables to be measured and power consumption in the wheel spindle, which can be easily measured. A sensor calibration methodology is presented, and the levels of error that can be expected are discussed. Validation of the new sensor is carried out by comparing the sensor's results with actual measurements carried out in an industrial grinding machine. Results show excellent estimation performance for both wheel wear and surface roughness. In the case of wheel wear, the absolute error is within the range of microns (average value 32 μm). In the case of surface finish, the absolute error is well below Ra 1 μm (average value 0.32 μm). The present approach can be easily generalized to other grinding operations. PMID:24854055

  3. Effect of edge roughness on electronic transport in graphene nanoribbon channel metal-oxide-semiconductor field-effect transistors

    NASA Astrophysics Data System (ADS)

    Basu, D.; Gilbert, M. J.; Register, L. F.; Banerjee, S. K.; MacDonald, A. H.

    2008-01-01

    Results of quantum mechanical simulations of the influence of edge disorder on transport in graphene nanoribbon metal-oxide-semiconductor field-effect transistors (MOSFETs) are reported. The addition of edge disorder significantly reduces ON-state currents and increases OFF-state currents, and introduces wide variability across devices. These effects decrease as ribbon widths increase and as edges become smoother. However, the band gap decreases with increasing width, thereby increasing the band-to-band tunneling mediated subthreshold leakage current even with perfect nanoribbons. These results suggest that without atomically precise edge control during fabrication, MOSFET performance gains through use of graphene will be difficult to achieve in complementary MOS applications.

  4. Bed roughness impedes then accelerates grounding line retreat of Thwaites glacier

    NASA Astrophysics Data System (ADS)

    Waibel, M. S.; Jackson, C. S.; Hulbe, C. L.; Martin, D. F.; Goff, J.

    2016-12-01

    The importance of bed shape to glacier mechanics is widely recognized. Variations in the size, shape, and distribution of obstacles on the bed influence basal drag, along- and across- flow velocity gradients, among other effects. We examine how different realizations of bed morphology affect simulations of Thwaites Glacier response to ocean warming and the occurrence of unstable grounding line retreat. The BISICLES ice sheet model is used to simulate ice sheet flow over two different bed configurations. The model uses a modified form of the L1L2 approximation in an adaptive mesh with a control method for initialization to match observations. The model is forced via melting under the floating ice using a slow ramp similar to the gradual forcings used in studies of ocean circulation tipping points. This allows us to identify the model year in which the glacier response rate exceeds the forcing rate, marking the onset of regional instability. At that point, the forcing is turned off and the unforced ice sheet continues to evolve. The bed configurations are the 1-km resolution interpolated BEDMAP2 bed and a higher-resolution conditional simulation created by interpolating aerogeophysical observations to a 250 m mesh using inhomogeneous statistics with channelized morphology and a realistic small-scale roughness. Our objective is to examine the geography of ice sheet instability and the ways in which choice of bed may influence projections of future change. We find that the higher-resolution, finer-detail bed geometry significantly impedes initiation of a regional instability, even as the grounding line retreats. This means that grounding lines on different beds are at different distances down the underlying bed slope at the moment of instability, and in turn that regional driving stresses have different magnitudes. A longer period of forcing prior to instability results in larger driving stresses (steeper surface slope and thicker ice near the grounding line) and

  5. Propagation of Degenerate Band-Edge Modes Using Dual Nonidentical Coupled Transmission Lines

    NASA Astrophysics Data System (ADS)

    Zuboraj, A. Muhammed; Sertel, B. Kubilay; Volakis, C. John L.

    2017-06-01

    Degenerate band-edge (DBE) modes are known for their exceptionally high field intensity at the nearly flat dispersion-diagram profile. Because of the latter property, resonances supported by these modes are associated with a very strong field at the band edge. DBE modes and similar resonances of this class have been typically realized by introducing anisotropic dielectric slabs in volumetric photonic crystals. By contrast, in this paper, we present an analytic model of DBE modes using a simple set of nonidentical coupled transmission lines. The unequal phase velocities of the supported waves supported by these transmission lines lead to mode degeneracy, that in turn provide quartic solutions of dispersion (ω -β ) relations. The DBE mode appears as one these quartic solutions. As such, the proposed model generalizes the concept of DBE modes using the construct of nonidentical coupled transmission lines. In this paper, we also propose a propagation medium using a dual pair of nonidentical transmission lines. The medium is referred to as a "butterfly" structure and is composed of four coupled transmission lines. These four coupled transmission lines generate the TM01-like degenerate band-edge mode. This is done by coupling the TE modes supported on each pair of the transmission lines. Mode purity at the resonance frequency and the intense field profile on the axis are properties that can be exploited for high-power microwave sources.

  6. A method to characterize the roughness of 2-D line features: recrystallization boundaries.

    PubMed

    Sun, J; Zhang, Y B; Dahl, A B; Conradsen, K; Juul Jensen, D

    2017-03-01

    A method is presented, which allows quantification of the roughness of nonplanar boundaries of objects for which the neutral plane is not known. The method provides quantitative descriptions of both the local and global characteristics. How the method can be used to estimate the sizes of rough features and local curvatures is also presented. The potential of the method is illustrated by quantification of the roughness of two recrystallization boundaries in a pure Al specimen characterized by scanning electron microscopy.

  7. Modelling of local carbon deposition on a rough test limiter exposed to the edge plasma of TEXTOR

    NASA Astrophysics Data System (ADS)

    Dai, Shuyu; Kirschner, A.; Matveev, D.; Borodin, D.; Björkas, C.; Sun, Jizhong; Wang, Dezhen

    2013-05-01

    A Monte-Carlo code called SURO was developed to study the influence of surface roughness on the impurity deposition characteristics in fusion experiments. SURO uses the test particle approach to describe the impact of background plasma and the deposition of impurity particles on a sinusoidal surface. The local impact angle and dynamic change of surface roughness as well as surface concentrations of different species due to erosion and deposition are taken into account. Coupled with the three-dimensional Monte-Carlo code ERO, SURO was used to study the impact of surface roughness on 13C deposition in 13CH4 injection experiments in TEXTOR. The simulations showed that the amount of net deposited 13C species increased with surface roughness. Parameter studies with varying 12C and 13C fluxes were performed to gain insights into impurity deposition characteristics on the rough surface. Calculations of the exposure time needed for surface smoothing for TEXTOR and ITER were also carried out for different scenarios.

  8. Effect of the addition of antimicrobial agents on Shore A hardness and roughness of soft lining materials.

    PubMed

    Urban, Vanessa M; Lima, Thiago F; Bueno, Mirian G; Giannini, Marcelo; Arioli Filho, João N; de Almeida, Ana Lúcia P F; Neppelenbroek, Karin H

    2015-04-01

    While the incorporation of antimicrobial agents into soft denture liners has been suggested as a reliable alternative treatment for denture stomatitis, it may affect the liner's properties. The effect of addition of antimicrobial agents for the treatment of denture stomatitis on the surface roughness and Shore A hardness of soft lining materials was evaluated. The test groups comprised specimens (36 × 7 × 6 mm(3) ) of soft materials (Softone and Trusoft) without (control) or with incorporation of drugs (nystatin, miconazole, ketoconazole, chlorhexidine diacetate, and itraconazole). Hardness (Shore A) and roughness (Ra) were evaluated after immersion of specimens (n = 10) in distilled water at 37°C for 24 hours, 7 and 14 days. Data were analyzed by 3-way ANOVA/Tukey's test (α = 0.05). After 14 days, an increase (p < 0.05) was observed in the hardness of soft materials with time for the modified specimens, except for itraconazole. Addition of drugs increased the Softone roughness only for the addition of miconazole and chlorhexidine (p < 0.05), and did not increase the roughness of Trusoft with time. Only chlorhexidine and itraconazole altered the roughness compared to the control for each material (p < 0.05). The smallest changes of hardness and roughness with time in the modified groups compared to controls were observed for itraconazole groups for both materials. © 2014 by the American College of Prosthodontists.

  9. High-resolution inkjet printing of electrically conducting lines of silver nanoparticles by edge-enhanced twin-line deposition

    NASA Astrophysics Data System (ADS)

    Bromberg, Vadim; Ma, Siyuan; Singler, Timothy J.

    2013-05-01

    We report a process for inkjet printing electrically continuous micron-wide lines of silver nanoparticles by exploiting edge-enhanced evaporation commonly associated with the coffee-stain effect. In situ and real-time flow observation confirmed preferential nanoparticle deposition at the contact line of printed rivulets. The resulting twin-pair of parallel continuous lines showed characteristic width (2-8 μm), height (100-300 nm), and pair spacing (100-600 μm) that depended on substrate and printing conditions in a theoretically predictable way. Thermally sintered lines were used to form rectilinear grids showing ˜5 Ω/◻ effective sheet resistance. The robustness of the deposition process was investigated, and line pathologies were found to depend on substrate surface wettability.

  10. Coexistence of diffusive resistance and ballistic persistent current in disordered metallic rings with rough edges: Possible origin of puzzling experimental values

    NASA Astrophysics Data System (ADS)

    Feilhauer, J.; Moško, M.

    2013-09-01

    Typical persistent current (Ityp) in a mesoscopic normal metal ring with disorder due to rough edges and random grain boundaries is calculated by use of a scattering matrix method. In addition, resistance of a corresponding metallic wire is obtained from the Landauer formula and the electron mean free path (l) is determined. If disorder is due to the rough edges, a ballistic persistent current Ityp≃evF/L is found to coexist with the diffusive resistance (∝L/l), where vF is the Fermi velocity and L≫l is the ring length. This ballistic current is due to a single electron that moves almost in parallel with the rough edges and thus hits them rarely (it is shown that this parallel motion exists in the ring geometry due to the Hartree-Fock interaction). Our finding agrees with a puzzling experimental result Ityp≃evF/L, reported by Chandrasekhar [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.67.3578 67, 3578 (1991)] for metallic rings of length L≃100l. If disorder is due to the grain boundaries, our data reproduce the theoretical result Ityp≃(evF/L)(l/L) that holds for the white-noise-like disorder and has been observed in recent experiments. Thus, result Ityp≃evF/L in a disordered metallic ring of length L≫l is as normal as result Ityp≃(evF/L)(l/L). Which result is observed depends on the nature of disorder. Experiments that would determine Ityp and l in correlation with the nature of disorder can be instructive.

  11. Dynamics of contact line motion during the wetting of rough surfaces and correlation with topographical surface parameters.

    PubMed

    Kubiak, K J; Wilson, M C T; Mathia, T G; Carras, S

    2011-01-01

    Dynamics of contact line motion and wettability is essential in many industrial applications such as liquid coating, lubrication, printing, painting, condensation, etc. However, the wettability of surfaces depends not only on liquid-solid chemical properties but also can be strongly affected by surface roughness. As a practical application of controlled wettability, we can mention the self-cleaning surfaces, protective clothing, microfluidics devices, electro wetting, etc. In this article, we experimentally investigate the spreading of droplets deposited onto rough surfaces. Anisotropic surfaces were prepared by abrasive polishing on the following materials: aluminium alloy AA7064, titanium alloy Ti-6Al-4V, steel AISI 8630, copper alloy UNS C17000, machinable glass ceramic, and poly-methylmethacrylate. Topographical 2D parameters were calculated according to the following standards, defining Geometrical Product Specifications (GPS): ISO 4287, ISO 12085, ISO 13565, ISO 12780, and ISO 12181. The influence of topographical parameters on wettability and spreading phenomenon has been evaluated by statistical covariance analysis. The following parameters have strong influence on fluid spreading on rough surfaces: R(mr) is the relative material ratio of the roughness profile, T(rc) is the microgeometric material ratio, P(mr) is the relative material ratio of the raw profile, K(r) is the mean slope of the roughness motifs, RON(t) is the peak to valley roundness deviation, and P(sk) is the Skewness of the raw profile. The physical meaning of selected parameters is discussed, and K(r) (the mean slope of the roughness motifs) is selected as the most important and physically meaningful parameter. It has been found that for all tested materials, fluid spreading shows increasing tendency when mean slope of the roughness motifs (K(r) ) increases. Copyright © 2011 Wiley Periodicals, Inc.

  12. Safety effects of wider edge lines on rural, two-lane highways.

    PubMed

    Park, Eun Sug; Carlson, Paul J; Porter, Richard J; Andersen, Carl K

    2012-09-01

    Although it is generally expected that wider lines will have a positive effect on vehicle safety, there have not been any convincing evidence based on the crash data analysis, partly because of the lack of relevant data. In this paper, the safety effect of wider edge lines was examined by analyzing crash frequency data for road segments with and without wider edge lines. The data from three states, Kansas, Michigan, and Illinois, have been analyzed. Because of different nature of data from each state, a different statistical analysis approach was employed for each state: an empirical Bayes, before-after analysis of Kansas data, an interrupted time series design and generalized linear segmented regression analysis of Michigan data, and a cross sectional analysis of Illinois data. Although it is well-known that causation is hard to establish based on observational studies, the results from three extensive statistical analyses all point to the same findings. The consistent findings lend support to the positive safety effects of wider edge lines installed on rural, two-lane highways. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Mutual synchronization of oscillating pulse edges in point-coupled transmission lines with regularly spaced tunnel diodes

    NASA Astrophysics Data System (ADS)

    Narahara, Koichi

    2017-01-01

    In this paper, we investigate the mutual synchronization of oscillating pulse edges developed in point-coupled transmission lines periodically loaded with tunnel diodes (TDs). When supplied with an appropriate voltage at the end of a TD line, a pulse edge exhibits a spatially extended limit-cycle oscillation on the line. In this study, the properties of this mutual synchronization of edge oscillation established in two coupled TD lines are discussed. We examine the mutual synchronization using phase sensitivity calculated by applying phase-reduction scheme to the transmission equation of a TD line. The phase difference between the synchronized edges and oscillation frequency is calculated depending on the coupling cell. We then validate the reduced model via time-domain calculations of edge oscillations.

  14. When Smoothening Makes It Rough: Unhindered Step-Edge Diffusion and the Meandering Instability on Metal Surfaces

    SciTech Connect

    Nita, F.; Pimpinelli, A.

    2005-09-02

    The precise microscopic origin of step meandering is not known in many real situations. A detailed study of this instability has been made for copper, and none of the microscopic mechanisms proposed until now is able to describe all of the observed characteristic features of the instability, in particular, its dependence on the crystallographic orientations of steps. We propose a novel scenario, and using kinetic Monte Carlo simulations we show that essentially all features of step meandering of copper can be explained, if atoms diffuse along step edges and freely turn around the kinks they encounter along the ledge. Then, in a rather counterintuitive way, step meandering appears due to the very mechanism -step-edge diffusion - that may be expected to oppose it.

  15. Numerical lifting line theory applied to drooped leading-edge wings below and above stall

    NASA Technical Reports Server (NTRS)

    Anderson, J. D., Jr.; Corda, S.; Van Wie, D. M.

    1980-01-01

    A numerical iterative solution to the classical Prandtl lifting-line theory, suitably modified for poststall behavior, is used to study the aerodynamic characteristics of straight rectangular finite wings with and without leading-edge droop. This study is prompted by the use of such leading-edge modifications to inhibit stall/spins in light general aviation aircraft. The results indicate that lifting-line solutions at high angle of attack can be obtained that agree with experimental data to within 20%, and much closer for many cases. Therefore, such solutions give reasonable preliminary engineering results for both drooped and undrooped wings in the poststall region. However, as predicted by von Karman, the lifting-line solutions are not unique when sectional negative lift slopes are encountered. In addition, the present numerical results always yield symmetrical lift distributions along the span, in contrast to the asymmetrical solutions observed by Schairer in the late 1930's. Finally, a series of parametric tests at low angle of attack indicate that the effect of drooped leading edges on aircraft cruise performance is minimal.

  16. Shifted knife-edge aperture digital in-line holography for fluid velocimetry.

    PubMed

    Palero, Virginia; Lobera, Julia; Andrés, Nieves; Arroyo, M Pilar

    2014-06-01

    We describe a digital holography technique that, with the simplicity of an in-line configuration, produces holograms where the real and virtual images are completely separated, as in an off-axis configuration. An in-line setup, in which the object is imaged near the sensor, is modified by placing a shifted knife-edge aperture that blocks half the frequency spectrum at the focal plane of the imaging lens. This simple modification of the in-line holographic configuration allows discriminating the virtual and real images. As a fluid velocimetry technique, the use of this aperture removes the minimum defocusing distance requisite and reduces the out-of-plane velocity measurement errors of classical in-line holography. Results with different test objects are shown.

  17. Roughness-Dominated Transition on Nosetips, Attachment Lines and Lifting-Entry Vehicles

    NASA Technical Reports Server (NTRS)

    Reda, Daniel C.

    2001-01-01

    Modeling of roughness-dominated transition is a critical design issue for both ablating and non-ablating thermal protection systems (TPS). Ablating TPS, used for planetary-entry and earth-return missions, first experience recession under high-altitude, low-Reynolds-number conditions. Such laminar-flow ablation causes the formation of a surface microroughness pattern characteristic of the TPS material composition and fabrication process. For non-ablating TPS, such as the overlapping-tile, metallic heatshields proposed for future reusable launch vehicles, the surface roughness pattern is established a priori by the engineering design and assembly procedure. In both cases, these distributed surface roughness patterns create disturbances within, and alter the mean velocity profile of, the laminar boundary layer flowing over the surface. As altitude decreases, Reynolds number increases, and flow field conditions capable of amplifying these roughness-induced perturbations are eventually achieved, i.e., transition onset occurs. Boundary layer transition to turbulence results in more severe heat-transfer rates. Ablating TPS experience increased recession rates, leading to potential bum-through, while non-ablating TPS experience accelerated temperature rise, leading to potential melting of key components.

  18. Ezrin enhances line tension along transcellular tunnel edges via NMIIa driven actomyosin cable formation

    PubMed Central

    Stefani, Caroline; Gonzalez-Rodriguez, David; Senju, Yosuke; Doye, Anne; Efimova, Nadia; Janel, Sébastien; Lipuma, Justine; Tsai, Meng Chen; Hamaoui, Daniel; Maddugoda, Madhavi P.; Cochet-Escartin, Olivier; Prévost, Coline; Lafont, Frank; Svitkina, Tatyana; Lappalainen, Pekka; Bassereau, Patricia; Lemichez, Emmanuel

    2017-01-01

    Transendothelial cell macroaperture (TEM) tunnels control endothelium barrier function and are triggered by several toxins from pathogenic bacteria that provoke vascular leakage. Cellular dewetting theory predicted that a line tension of uncharacterized origin works at TEM boundaries to limit their widening. Here, by conducting high-resolution microscopy approaches we unveil the presence of an actomyosin cable encircling TEMs. We develop a theoretical cellular dewetting framework to interpret TEM physical parameters that are quantitatively determined by laser ablation experiments. This establishes the critical role of ezrin and non-muscle myosin II (NMII) in the progressive implementation of line tension. Mechanistically, fluorescence-recovery-after-photobleaching experiments point for the upstream role of ezrin in stabilizing actin filaments at the edges of TEMs, thereby favouring their crosslinking by NMIIa. Collectively, our findings ascribe to ezrin and NMIIa a critical function of enhancing line tension at the cell boundary surrounding the TEMs by promoting the formation of an actomyosin ring. PMID:28643776

  19. Ezrin enhances line tension along transcellular tunnel edges via NMIIa driven actomyosin cable formation

    NASA Astrophysics Data System (ADS)

    Stefani, Caroline; Gonzalez-Rodriguez, David; Senju, Yosuke; Doye, Anne; Efimova, Nadia; Janel, Sébastien; Lipuma, Justine; Tsai, Meng Chen; Hamaoui, Daniel; Maddugoda, Madhavi P.; Cochet-Escartin, Olivier; Prévost, Coline; Lafont, Frank; Svitkina, Tatyana; Lappalainen, Pekka; Bassereau, Patricia; Lemichez, Emmanuel

    2017-06-01

    Transendothelial cell macroaperture (TEM) tunnels control endothelium barrier function and are triggered by several toxins from pathogenic bacteria that provoke vascular leakage. Cellular dewetting theory predicted that a line tension of uncharacterized origin works at TEM boundaries to limit their widening. Here, by conducting high-resolution microscopy approaches we unveil the presence of an actomyosin cable encircling TEMs. We develop a theoretical cellular dewetting framework to interpret TEM physical parameters that are quantitatively determined by laser ablation experiments. This establishes the critical role of ezrin and non-muscle myosin II (NMII) in the progressive implementation of line tension. Mechanistically, fluorescence-recovery-after-photobleaching experiments point for the upstream role of ezrin in stabilizing actin filaments at the edges of TEMs, thereby favouring their crosslinking by NMIIa. Collectively, our findings ascribe to ezrin and NMIIa a critical function of enhancing line tension at the cell boundary surrounding the TEMs by promoting the formation of an actomyosin ring.

  20. Edge pinning and transformation of defect lines induced by faceted colloidal rings in nematic liquid crystals

    NASA Astrophysics Data System (ADS)

    Senyuk, Bohdan; Liu, Qingkun; Yuan, Ye; Smalyukh, Ivan I.

    2016-06-01

    Nematic colloids exhibit a large diversity of topological defects and structures induced by colloidal particles in the orientationally ordered liquid crystal host fluids. These defects and field configurations define elastic interactions and medium-mediated self-assembly, as well as serve as model systems in exploiting the richness of interactions between topologies and geometries of colloidal surfaces, nematic fields, and topological singularities induced by particles in the nematic bulk and at nematic-colloidal interfaces. Here we demonstrate formation of quarter-strength surface-pinned disclinations, as well as a large variety of director field configurations with splitting and reconnections of singular defect lines, prompted by colloidal particles with sharp edges and size large enough to define strong boundary conditions. Using examples of faceted ring-shaped particles of genus g =1 , we explore transformation of defect lines as they migrate between locations in the bulk of the nematic host to edge-pinned locations at the surfaces of particles and vice versa, showing that this behavior is compliant with topological constraints defined by mathematical theorems. We discuss how transformation of bulk and surface defect lines induced by faceted colloids can enrich the diversity of elasticity-mediated colloidal interactions and how these findings may impinge on prospects of their controlled reconfigurable self-assembly in nematic hosts.

  1. Electron-beam lithography with character projection exposure for throughput enhancement with line-edge quality optimization

    NASA Astrophysics Data System (ADS)

    Ikeno, Rimon; Maruyama, Satoshi; Mita, Yoshio; Ikeda, Makoto; Asada, Kunihiro

    2016-03-01

    Among various electron-beam lithography (EBL) techniques, variable-shaped beam (VSB) and character projection (CP) methods have attracted many EBL users for their high-throughput feature, but they are considered to be more suited to small-featured VLSI fabrication with regularly-arranged layouts like standard-cell logics and memory arrays. On the other hand, non-VLSI applications like photonics, MEMS, MOEMS, and so on, have not been fully utilized the benefit of CP method due to their wide variety of layout patterns. In addition, the stepwise edge shapes by VSB method often causes intolerable edge roughness to degrade device characteristics from its intended performance with smooth edges. We proposed an overall EBL methodology applicable to wade-variety of EBL applications utilizing VSB and CP methods. Its key idea is in our layout data conversion algorithm that decomposes curved or oblique edges of arbitrary layout patterns into CP shots. We expect significant reduction in EB shot count with a CP-bordered exposure data compared to the corresponding VSB-alone conversion result. Several CP conversion parameters are used to optimize EB exposure throughput, edge quality, and resultant device characteristics. We demonstrated out methodology using the leading-edge VSB/CP EBL tool, ADVANTEST F7000S-VD02, with high resolution Hydrogen Silsesquioxane (HSQ) resist. Through our experiments of curved and oblique edge lithography under various data conversion conditions, we learned correspondence of the conversion parameters to the resultant edge roughness and other conditions. They will be utilized as the fundamental data for further enhancement of our EBL strategy for optimized EB exposure.

  2. Attachment-Line Transition Due to Roughness on a 76 Degree Swept Cylinder at Mach 1.6

    NASA Technical Reports Server (NTRS)

    Coleman, Colin P.; Poll, D. I. A.

    1998-01-01

    Experiments were conducted on a 76 deg. swept cylinder to establish the conditions for the attachment-line transition process with, and without, surface roughness in a low-disturbance ("quiet"), Mach number 1.6 flow. Local flow parameters were estimated from pressure measurements. These were in good agreement with predictions from an Euler code (CFL3D) and a boundary layer code (BL3D). Hot-wires and Schlieren photography were used to determine the state of the boundary layer. It was found that, for a near-adiabatic wall condition and a smooth surface, the attachment-line, boundary-layer remained laminar up to the highest attainable Reynolds number (R-bar of 790). Transition under the influence of trip wires was found to depend on wind-tunnel disturbance levels and the onset conditions have been established. Results suggest that current design practice, which is based upon data from conventional ("noisy") tunnels, may be highly conservative.

  3. Changes in the electronic structure of highly compressed iron revealed by X-ray fluorescence lines and absorption edges

    NASA Astrophysics Data System (ADS)

    Hansen, S. B.; Harding, E. C.; Knapp, P. F.; Gomez, M. R.; Nagayama, T.; Bailey, J. E.

    2017-09-01

    We present high-resolution spectroscopic data from iron impurities in beryllium liners driven by Sandia's Z machine to temperatures near 10 eV and electron densities near 2 × 1024 cm-3, conditions independently diagnosed from the transmission depth and shape of the iron K-edge. A 12-eV redshift is observed in the Fe Kβ fluorescence line along with few-eV shifts in the Fe Kα lines and Fe K-shell absorption edge. While the measured edge shift disagrees with several common models of ionization potential depression, both line and edge shifts are in good agreement with the predictions of a self-consistent model based on density functional theory.

  4. Hydrophobic marking line used to eliminate the edge effect in a microfluidic point-of-care testing device

    NASA Astrophysics Data System (ADS)

    Jingmin, Li; Xia, Li; Ziyang, Liu; Chao, Liang; Chong, Liu

    2017-01-01

    The traversal rate for the liquid medium near a point-of-care testing (POCT) device microfluidic channel edge is faster than that through the body of the channel, which makes the fluid front meniscus becomes concave rather than convex or flat. The concave front is unwished due to its influences on quantitative analysis accuracy and the possibility to generate air bubbles. Here, a unique method, named hydrophobic marking line, is demonstrated. This method used a soft pen with hydrophobic ink to draw two lines along the edges of the channel of a POCT device. Results have shown that the marking lines will eliminate the edge effects and generate convex liquid front. The curvature of the liquid front can be changed by adjusting the marking line width or ink solutions.

  5. Semi-contact-writing of polymer molds for prototyping PDMS chips with low surface roughness, sharp edges and locally varying channel heights

    NASA Astrophysics Data System (ADS)

    Gutzweiler, Ludwig; Stumpf, Fabian; Tanguy, Laurent; Roth, Guenter; Koltay, Peter; Zengerle, Roland; Riegger, Lutz

    2016-04-01

    Microfluidic systems fabricated in polydimethylsiloxane (PDMS) enable a broad variety of applications and are widespread in the field of Lab-on-a-Chip. Here we demonstrate semi-contact-writing, a novel method for fabrication of polymer based molds for casting microfluidic PDMS chips in a highly flexible, time and cost-efficient manner. The method is related to direct-writing of an aqueous polymer solution on a planar glass substrate and substitutes conventional, time- and cost-consuming UV-lithography. This technique facilitates on-demand prototyping in a low-cost manner and is therefore ideally suited for rapid chip layout iterations. No cleanroom facilities and less expertise are required. Fabrication time from scratch to ready-to-use PDMS-chip is less than 5 h. This polymer writing method enables structure widths down to 140 μm and controllable structure heights ranging from 5.5 μm for writing single layers up to 98 μm by stacking. As a unique property, freely selectable height variations across a substrate can be achieved by application of local stacking. Furthermore, the molds exhibit low surface roughness (R a   =  24 nm, R RMS  =  28 nm) and high fidelity edge sharpness. We validated the method by fabrication of molds to cast PDMS chips for droplet based flow-through PCR with single-cell sensitivity.

  6. Contact line pinning of a perfectly wetting and volatile liquid at a sharp edge

    NASA Astrophysics Data System (ADS)

    Tsoumpas, Yannis; Dehaeck, Sam; Rednikov, Alexey; Colinet, Pierre

    2011-11-01

    According to the Gibbs' criterion, a sharp edge can act as an energy barrier during the spreading of a liquid drop on a rigid substrate. In this study, however, we are trying to determine experimentally whether Gibbs' criterion is also valid for the case of a perfectly wetting and volatile liquid. To this purpose, we constructed a groove of triangular cross section on a Plexiglas substrate. During the experiments liquid was injected in the region surrounded by the groove, which had a square shape with rounded corners. The results indicated that a microgroove edge can indeed prevent the spreading of the liquid drop up to a certain extent, with the maximum apparent contact angle being in close agreement with the one given by Gibbs' criterion. Nevertheless, the apparent contact angle at breakup was found to be significantly lower in the corner of our region. To study this further we developed a static model, which takes into account surface tension and gravity but not the evaporation. Both the simulations and the experiments have confirmed a remarkable behaviour of the contact line at the corner. Finally, to grasp the effect of evaporation, experiments have also been conducted with drops of equally wetting but less volatile liquids. Supported by ESA & BELSPO, by the EU, and by FRS-FNRS.

  7. Line width roughness reduction by rational design of photoacid generator for sub-millisecond laser post-exposure bake

    NASA Astrophysics Data System (ADS)

    Jiang, Jing; Thompson, Michael O.; Ober, Christopher K.

    2014-03-01

    Sub-millisecond laser post-exposure bake (PEB) is an alternative technology to address the excessive acid diffusion for chemically amplified photoresist systems. By rationally designing the resist, laser post-exposure bake is able to improve the resolution and reduce the line width roughness (LWR) compared to patterns exposed under the same conditions but using conventional hotplate PEB. It was found that only the resist with high deprotection activation energy and low diffusion activation energy showed improved performance using laser PEB. Accordingly, a PAG was designed to have low acid diffusivity by binding the counter ions to a molecular glass core while keeping photophysical properties and processing conditions similar to a conventional PAG. By reducing the diffusivity of the counter ions, the PAG was able to further reduce LWR by 60% using laser PEB.

  8. De-pinning of contact line of droplets on rough surfaces

    NASA Astrophysics Data System (ADS)

    Madhurima, V.; Nilavarasi, K.

    2016-10-01

    The present study reports the formation of self-assembled droplet pattern on the PDMS polymer coated over grooved side of DVD under saturated vapours of alcohols. Comparison of the results with breath figures formed over unconstrained side of DVD is made. Four different environments namely methanol, ethanol, 2-propanol and n-butanol are used for the analysis. It is observed that the pattern formation occurs with methanol and ethanol vapours and not with 2-propanol and n-butanol. The difference is pattern formation with different alcohols is attributed to the variation in chain length and the presence of hydrophobic groups in alcohols, as given by Traube's rule. The distortion of patterns over constrained surface is attributed to the depinning of contact lines.

  9. Numerical Predictions of Sonic Boom Signatures for a Straight Line Segmented Leading Edge Model

    NASA Technical Reports Server (NTRS)

    Elmiligui, Alaa A.; Wilcox, Floyd J.; Cliff, Susan; Thomas, Scott

    2012-01-01

    A sonic boom wind tunnel test was conducted on a straight-line segmented leading edge (SLSLE) model in the NASA Langley 4- by 4- Foot Unitary Plan Wind Tunnel (UPWT). The purpose of the test was to determine whether accurate sonic boom measurements could be obtained while continuously moving the SLSLE model past a conical pressure probe. Sonic boom signatures were also obtained using the conventional move-pause data acquisition method for comparison. The continuous data acquisition approach allows for accurate signatures approximately 15 times faster than a move-pause technique. These successful results provide an incentive for future testing with greatly increased efficiency using the continuous model translation technique with the single probe to measure sonic boom signatures. Two widely used NASA codes, USM3D (Navier-Stokes) and CART3D-AERO (Euler, adjoint-based adaptive mesh), were used to compute off-body sonic boom pressure signatures of the SLSLE model at several different altitudes below the model at Mach 2.0. The computed pressure signatures compared well with wind tunnel data. The effect of the different altitude for signature extraction was evaluated by extrapolating the near field signatures to the ground and comparing pressure signatures and sonic boom loudness levels.

  10. Scatterometry modeling for gratings with roughness and irregularities

    NASA Astrophysics Data System (ADS)

    Bischoff, Joerg; Hehl, Karl

    2016-03-01

    A rigorous electromagnetic simulation method for grating diffraction is presented that concurrently enables appropriate roughness and irregularity modeling. The approach will it make possible for example to overlay surface roughness and or line edge roughness (LER) to regular patterns. In this way, a unique tool is provided to model diffraction and scattering at the same time. It is based on a combination of modal methods such as the RCWA or C-method with near field stitching and subsequent near-to-far field propagation. This paves the way to an efficient and accurate modeling of large scattering areas. Fields of applications are the design of spectrographic gratings as well as optical scatterometry or kindred optical metrology techniques. Examples are provided both for 2D line/space patterns with sinusoidal and blaze profiles and 3D line/space patterns possessing LER and line width roughness (LWR). First ideas are derived how to determine LER and LWR from scatterometric measurements.

  11. Theoretical study of relationships among resolution, line width roughness, and sensitivity of chemically amplified extreme ultraviolet resists with photodecomposable quenchers

    NASA Astrophysics Data System (ADS)

    Kozawa, Takahiro; Santillan, Julius Joseph; Itani, Toshiro

    2016-11-01

    The resolution of chemically amplified extreme ultraviolet (EUV) resists has reached 13-15 nm. However, the line width roughness (LWR) and sensitivity are still inadequate for their application to the high-volume production of semiconductor devices. In this study, the performance of chemically amplified resists with photodecomposable quenchers were investigated by simulation based on the sensitization and reaction mechanisms of chemically amplified EUV resists. The relationships among resolution, LWR, and sensitivity were evaluated in the half-pitch ranges of 12-16 nm. The requirements for 20 mJ cm-2 and 10% critical dimension (CD) LWR are considered to be within the physical limits in the half-pitch range of 12-16 nm when an optical image with a contrast of 1 (normalized image log slope of π) is given. Depending on the given image quality and the required sensitivity, the optimization of sensitizer concentration and the increase in resist absorption coefficient and/or effective reaction radius for deprotection are required to achieve 10% CD LWR.

  12. Revisiting the mechanisms involved in Line Width Roughness smoothing of 193 nm photoresist patterns during HBr plasma treatment

    SciTech Connect

    Brihoum, M.; Ramos, R.; Menguelti, K.; Cunge, G.; Pargon, E.; Joubert, O.

    2013-01-07

    HBr plasma treatments are widely used in nanoscale lithographic technologies to increase the plasma etch resistance of 193 nm photoresist masks as well as to decrease their Line Width Roughness (LWR). VUV irradiation of the photoresist is known to play a major role in this process by inducing polymer chains rearrangement and finally LWR reduction. However, in the plasma environment (i.e., with radical and ion bombardment), the interaction layer formed at the resist surface perturbs this mechanism and a lower LWR reduction is achieved compared to VUV only treatment. So far the nature of the interaction layer, its formation mechanism and its relation with the resist pattern LWR were all unclear. In this paper, we show that a graphite-like layer is formed on the resist patterns by the redeposition of carbon-based species originating from the plasma dissociation of outgassed photo-etched resist moieties. We show that the presence of this layer inhibits the LWR minimization and causes an increase in the LWR when it becomes thick enough (i.e., a few nanometers). We present evidences that the difference in the mechanical properties of the graphite-like top layer which coats the resist patterns and the bulk of the resist patterns is correlated to the LWR after plasma treatment. We can conclude that the optimization of an HBr cure process relies on the minimization of the carbon redeposition while keeping a significant VUV light flux and we show that this can be achieved by using pulsed plasma processes.

  13. A new beam emission polarimetry diagnostic for measuring the magnetic field line angle at the plasma edge of ASDEX Upgrade

    SciTech Connect

    Viezzer, E. E-mail: eviezzer@us.es; Dux, R.; Dunne, M. G.

    2016-11-15

    A new edge beam emission polarimetry diagnostic dedicated to the measurement of the magnetic field line angle has been installed on the ASDEX Upgrade tokamak. The new diagnostic relies on the motional Stark effect and is based on the simultaneous measurement of the polarization direction of the linearly polarized π (parallel to the electric field) and σ (perpendicular to the electric field) lines of the Balmer line D{sub α}. The technical properties of the system are described. The calibration procedures are discussed and first measurements are presented.

  14. A new beam emission polarimetry diagnostic for measuring the magnetic field line angle at the plasma edge of ASDEX Upgrade.

    PubMed

    Viezzer, E; Dux, R; Dunne, M G

    2016-11-01

    A new edge beam emission polarimetry diagnostic dedicated to the measurement of the magnetic field line angle has been installed on the ASDEX Upgrade tokamak. The new diagnostic relies on the motional Stark effect and is based on the simultaneous measurement of the polarization direction of the linearly polarized π (parallel to the electric field) and σ (perpendicular to the electric field) lines of the Balmer line Dα. The technical properties of the system are described. The calibration procedures are discussed and first measurements are presented.

  15. On Production Mechanisms For Balmer Line Radiation From 'Cold' Atomic Hydrogen and Deuterium In Fusion Edge Plasmas

    SciTech Connect

    Hey, John Douglas

    2010-10-29

    Published arguments, which assign dominant roles to atomic metastability and molecular ion dissociation in the production of 'narrow' Zeeman component Balmer line radiation from the tokamak edge plasma, have been examined critically in relation to: l-redistribution by proton collisions, molecular ion-proton equipartition, and ion acceleration by the plasma sheath (scrape-off layer) potential. These processes are found to constrain the contributions from metastable atoms and from dissociative excitation of molecular ions to 'narrow' Balmer spectra emitted from the plasma edge, in relation to the corresponding contributions from electron impact-induced dissociative excitation of neutral molecules.

  16. Feasibility of line-ratio spectroscopy on helium and neon as edge diagnostic tool for Wendelstein 7-X.

    PubMed

    Barbui, T; Krychowiak, M; König, R; Schmitz, O; Muñoz Burgos, J M; Schweer, B; Terra, A

    2016-11-01

    A beam emission spectroscopy system on thermal helium (He) and neon (Ne) has been set up at Wendelstein 7-X to measure edge electron temperature and density profiles utilizing the line-ratio technique or its extension by the analysis of absolutely calibrated line emissions. The setup for a first systematic test of these techniques of quantitative atomic spectroscopy in the limiter startup phase (OP1.1) is reported together with first measured profiles. This setup and the first results are an important test for developing the technique for the upcoming high density, low temperature island divertor regime.

  17. Feasibility of line-ratio spectroscopy on helium and neon as edge diagnostic tool for Wendelstein 7-X

    NASA Astrophysics Data System (ADS)

    Barbui, T.; Krychowiak, M.; König, R.; Schmitz, O.; Muñoz Burgos, J. M.; Schweer, B.; Terra, A.

    2016-11-01

    A beam emission spectroscopy system on thermal helium (He) and neon (Ne) has been set up at Wendelstein 7-X to measure edge electron temperature and density profiles utilizing the line-ratio technique or its extension by the analysis of absolutely calibrated line emissions. The setup for a first systematic test of these techniques of quantitative atomic spectroscopy in the limiter startup phase (OP1.1) is reported together with first measured profiles. This setup and the first results are an important test for developing the technique for the upcoming high density, low temperature island divertor regime.

  18. Near-coincident K-line and K-edge energies as ionization diagnostics for some high atomic number plasmas

    SciTech Connect

    Pereira, N. R.; Weber, B. V.; Phipps, D. G.; Schumer, J. W.; Seely, J. F.; Carroll, J. J.; Vanhoy, J. R.; Slabkowska, K.; Polasik, M.

    2012-10-15

    For some high atomic number atoms, the energy of the K-edge is tens of eVs higher than the K-line energy of another atom, so that a few eV increase in the line's energy results in a decreasing transmission of the x-ray through a filter of the matching material. The transmission of cold iridium's Asymptotically-Equal-To 63.287 keV K{alpha}{sub 2} line through a lutetium filter is 7% lower when emitted by ionized iridium, consistent with an energy increase of {Delta}{epsilon} Asymptotically-Equal-To 10{+-}1 eV associated with the ionization. Likewise, the transmission of the K{beta}{sub 1} line of ytterbium through a near-coincident K-edge filter changes depending on plasma parameters that should affect the ionization. Systematic exploration of filter-line pairs like these could become a unique tool for diagnostics of suitable high energy density plasmas.

  19. Slip-line modeling of machining with a rounded-edge tool—Part I: new model and theory

    NASA Astrophysics Data System (ADS)

    Fang, N.

    2003-04-01

    The effect of tool edge roundness attracts growing attention from the international machining research community due to ever accelerating applications of precision, super-precision, micro-, and nano-machining technologies in a wide variety of modern industries. A new slip-line model for machining with a rounded-edge tool and its associated hodograph are proposed in this paper. The model consists of 27 slip-line sub-regions, each sub-region having its own physical meaning. It is demonstrated that the model simultaneously takes into account nine effects, such as the shear-zone effect and the size effect, which commonly occur in machining. Eight groups of machining parameters, such as the ploughing (parasitic or non-cutting) force and the chip up-curl radius, can be simultaneously predicted from the model. Furthermore, the model incorporates eight slip-line models previously developed for machining during the last six decades as special cases. An additional special case that involves a parallel-sided shear zone can also be derived from the new model. A mathematical formulation of the model is established based on Dewhurst and Collins's (1973) matrix technique for numerically solving slip-line problems. A purely analytical equation is proposed to predict the thickness of the primary shear zone. This equation is also employed to predict the shear strain-rate in the primary shear zone.

  20. Environmental scanning electron microscopy study of the fine structure of the triple line and cassie-wenzel wetting transition for sessile drops deposited on rough polymer substrates.

    PubMed

    Bormashenko, Edward; Bormashenko, Yelena; Stein, Tamir; Whyman, Gene; Pogreb, Roman; Barkay, Zahava

    2007-04-10

    The wetting of rough honeycomb micrometrically scaled polymer substrates was studied. A very strong dependence of the apparent contact angle on the drop volume has been established experimentally. The environmental scanning electron microscopy study of the fine structure of the triple line is reported first. The triple line is not smooth and prefers grasping the polymer matrix over air holes. The precursor rim surrounding the drop has been observed. The revealed dependence of the apparent contact angle on the drop volume is explained by the transition between the pure Cassie and combined Wenzel-Cassie wetting regimes, which is induced by capillarity penetration of water into the holes of relief.

  1. Mask roughness induced LER: a rule of thumb -- paper

    SciTech Connect

    McClinton, Brittany; Naulleau, Patrick

    2010-03-12

    Much work has already been done on how both the resist and line-edge roughness (LER) on the mask affect the final printed LER. What is poorly understood, however, is the extent to which system-level effects such as mask surface roughness, illumination conditions, and defocus couple to speckle at the image plane, and currently factor into LER limits. Here, we propose a 'rule-of-thumb' simplified solution that provides a fast and powerful method to obtain mask roughness induced LER. We present modeling data on an older generation mask with a roughness of 230 pm as well as the ultimate target roughness of 50 pm. Moreover, we consider feature sizes of 50 nm and 22 nm, and show that as a function of correlation length, the LER peaks at the condition that the correlation length is approximately equal to the resolution of the imaging optic.

  2. Equations and charts for the rapid estimation of hinge-moment and effectiveness parameters for trailing-edge controls having leading and trailing edges swept ahead of the Mach lines

    NASA Technical Reports Server (NTRS)

    Goin, Kennith L

    1951-01-01

    Existing conical-flow solutions have been used to calculate the hinge-moments and effectiveness parameters of trailing-edge controls having leading and trailing edges swept ahead of the Mach lines and having streamwise root and tip chords. Equations and detailed charts are presented for the rapid estimation of these parameters. Also included is an approximate method by which these parameters may be corrected for airfoil-section thickness.

  3. Using the Secondary Electrons (SE) of scanning electron microscope with NIST`s MONSEL-II program to obtain improved linewidth measurements and slope angles of line edges on a MMIC GaAs device

    SciTech Connect

    Sartore, R.G.

    1996-12-31

    In the evaluation of GaAs devices from the MMIC (Monolithic Microwave Integrated Circuits) program for Army applications, there was a requirement to obtain accurate linewidth measurements on the nominal 0.5 micrometer gate lengths used to fabricate these devices. Preliminary measurements indicated a significant variation (typically 10% to 30% but could be more) in the critical dimensional measurements of the gate length, gate to source distance and gate to drain distance. Passivation introduced a margin of error, which was removed by plasma etching. Additionally, the high aspect ratio (4-5) of the thick gold (Au) conductors also introduced measurement difficulties. The final measurements were performed were performed after the thick gold conductor was removed and only the barrier metal remained, which was approximately 250 nanometer thick platinum on GaAs substrate. The thickness was measured using the penetration voltage method. Linescan of the secondary electron signal as it scans across the gate is shown in Figure 1. This linescan is an average of 5 linescans in the immediate vicinity to reduce noise levels. A SEM image of the area is shown in Figure 2. To obtain a rough estimate of the slopes of the gate lines at the edges, the sample was tilted to 75 degrees and the image in Figure 3 was obtained. From this figure a rough estimate of the sloped edges, using a protractor, was obtained, approximately 27 degrees, +/-5 degrees.

  4. Coupling analysis at the coupler and edge-coupled unilateral fin line

    NASA Astrophysics Data System (ADS)

    Fernandes, Humberto C. C.; Silva, Sidney A.; Silva, Jose P.

    1998-11-01

    Computer programs are developed in FORTRAN 77 and Matlab for Windows languages, given the results in 3-D of the dispersion and of the coupling, as functions of the frequency, conductivity and permittivity for the unilateral fin lines coupler asymmetric in E-plane, on semiconductor substrate. The characteristic impedance and complex propagation constant, for the odd and even-modes excitation are obtained by Transverse Transmission Line method -- TTL. These programs are easily used in graduate and undergraduate courses with good efficiency.

  5. High-precision drop shape analysis (HPDSA) of quasistatic contact angles on silanized silicon wafers with different surface topographies during inclining-plate measurements: Influence of the surface roughness on the contact line dynamics

    NASA Astrophysics Data System (ADS)

    Heib, F.; Hempelmann, R.; Munief, W. M.; Ingebrandt, S.; Fug, F.; Possart, W.; Groß, K.; Schmitt, M.

    2015-07-01

    Contact angles and wetting of solid surfaces are strongly influenced by the physical and chemical properties of the surfaces. These influence quantities are difficult to distinguish from each other if contact angle measurements are performed by measuring only the advancing θa and the receding θr contact angle. In this regard, time-dependent water contact angles are measured on two hydrophobic modified silicon wafers with different physical surface topographies. The first surface is nearly atomically flat while the second surface is patterned (alternating flat and nanoscale rough patterns) which is synthesized by a photolithography and etching procedure. The different surface topographies are characterized with atomic force microscopy (AFM), Fourier transform infrared reflection absorption spectroscopy (FTIRRAS) and Fourier transform infrared attenuated total reflection spectroscopy (FTIR-ATR). The resulting set of contact angle data obtained by the high-precision drop shape analysis approach is further analyzed by a Gompertzian fitting procedure and a statistical counting procedure in dependence on the triple line velocity. The Gompertzian fit is used to analyze overall properties of the surface and dependencies between the motion on the front and the back edge of the droplets. The statistical counting procedure results in the calculation of expectation values E(p) and standard deviations σ(p) for the inclination angle φ, contact angle θ, triple line velocity vel and the covered distance of the triple line dis relative to the first boundary points XB,10. Therefore, sessile drops during the inclination of the sample surface are video recorded and different specific contact angle events in dependence on the acceleration/deceleration of the triple line motion are analyzed. This procedure results in characteristically density distributions in dependence on the surface properties. The used procedures lead to the possibility to investigate influences on contact

  6. A possible edge effect in enhanced network. [solar K-line observations by multichannel spectrometer

    NASA Technical Reports Server (NTRS)

    Jones, H. P.; Brown, D. R.

    1977-01-01

    K-line observations of enhanced network taken with the NASA/SPO Multichannel Spectrometer on September 28, 1975, in support of OSO-8 are discussed. The data show a correlation between core brightness and asymmetry for spatial scans which cross enhanced network boundaries. The implications of this result concerning mass flow in and near supergranule boundaries are discussed.

  7. The Line Motion Illusion: The Detection of Counterchanging Edge and Surface Contrast

    ERIC Educational Resources Information Center

    Hock, Howard S.; Nichols, David F.

    2010-01-01

    A version of the line motion illusion (LMI) occurs when one of two adjacent surfaces changes in luminance; a new surface is perceived sliding in front of the initially presented surface. Previous research has implicated high-level mechanisms that can create or modulate LMI motion via feedback to lower-level motion detectors. It is shown here that…

  8. A possible edge effect in enhanced network. [solar K-line observations by multichannel spectrometer

    NASA Technical Reports Server (NTRS)

    Jones, H. P.; Brown, D. R.

    1977-01-01

    K-line observations of enhanced network taken with the NASA/SPO Multichannel Spectrometer on September 28, 1975, in support of OSO-8 are discussed. The data show a correlation between core brightness and asymmetry for spatial scans which cross enhanced network boundaries. The implications of this result concerning mass flow in and near supergranule boundaries are discussed.

  9. Line Ratio Diagnostics Along the Disc of Two Edge-on Lenticular Galaxies, NGC 4710 and NGC 5866

    NASA Astrophysics Data System (ADS)

    Topal, Selcuk; Bureau, Martin; Davis, Timothy A.; Young, Lisa; Krips, Melanie

    2015-01-01

    We present interferometric observations of CO lines (12CO(1-0, 2-1) and 13CO(1-0, 2-1)) and dense gas tracers (HCN(1-0), HCO+(1-0), HNC(1-0) and HNCO(4-3)) in two nearby edge-on barred lenticular galaxies, NGC4710 and NGC5866, with most of the gas concentrated in a nuclear disc and an inner ring in each galaxy. We probe the physical conditions of a two-component molecular interstellar medium in each galaxy and each kinematic component by using molecular line ratio diagnostics in three complementary ways. First, we measure the ratios of the position-velocity diagrams of different lines, second we measure the ratios of each kinematic component's integrated line intensities as a function of projected position, and third we model these line ratios using a non-local thermodynamic equilibrium radiative transfer code. Overall, the nuclear discs appear to have a tenuous molecular gas component that is hotter, optically thinner and with a larger dense gas fraction than that in the inner rings, suggesting more dense clumps immersed in a hotter more diffuse molecular medium. This is consistent with evidence that the physical conditions in the nuclear discs are similar to those in photo-dissociation regions. A similar picture emerges when comparing the observed molecular line ratios with those of other galaxy types. The physical conditions of the molecular gas in the nuclear discs of NGC4710 and NGC5866 thus appear intermediate between those of spiral galaxies and starbursts, while the star formation in their inner rings is even milder.

  10. Spectral line shapes of U M2 - and As K -edge resonant x-ray scattering in the two antiferromagnetic phases of UAs

    NASA Astrophysics Data System (ADS)

    Normile, P. S.; Wilkins, S. B.; Detlefs, B.; Mannix, D.; Blackburn, E.; Bouchenoire, L.; Bernhoeft, N.; Lander, G. H.

    2007-05-01

    We present resonant x-ray scattering measurements on uranium arsenide at the U M2 and As K absorption edges. The studies at both edges relate to aspects of the hybridization (involving the 5f states) in UAs. At the U M2 edge, the spectral line shapes are found to differ between the two antiferromagnetic phases of UAs. In the “type-I” phase, the line shapes may be fitted using a single resonant component, whereas in the “type-IA” phase, a second resonant component, 3.5eV above the first component, is required to fit the line shapes in the rotated polarization (σ→π) scattering channel. The possibility that the single (first) component in the type-I (type-IA) phase corresponds to E2 scattering due to the ordered 5f magnetic-dipole moments and that in the type-IA phase the second component represents an E1 process involving polarized 6d (U) states is considered. Similar line shapes are observed for the two antiferromagnetic phases at the As K edge, a result which is in discordance with a recent theoretical prediction. The experimentally observed As K -edge line shape has an asymmetrical form in both phases, which possibly relates to As 4p -band effects unaccounted for in the theory.

  11. Leading on the edge: The nature of paramedic leadership at the front line of care.

    PubMed

    Mercer, Danielle; Haddon, Arlene; Loughlin, Catherine

    2016-07-27

    Health care organizations are considered complex systems that represent both formal leadership as well as more informal and shared leadership models. Implementing these models is essential for optimizing care and patient outcomes. The paramedic profession specifically, although considered informally, leads out of hospital patient care. To date, few empirical studies investigate shared leadership in health care settings. In paramedicine specifically, studies of leadership are scarce, despite paramedics' essential role in leading on the front lines of care. Using an exemplar of paramedics, we examine what it means to informally lead on the front lines of patient care with the emphasis on paramedics responding out of hospital. We employed a qualitative, semistructured interview methodology with 29 paramedics from a group of companies in central/eastern Canada to explore the conditions and practices surrounding shared leadership. Paramedics argue that, despite their job title, they classify themselves as informal leaders who share the leadership role. More specifically, the paramedics discuss the precursors, practices, and structural conditions surrounding shared leadership within the realm of emergency medical services. They note that they often face out-of-hospital care without a formal manager, requiring them to collectively lead. The leader will shift in times of urgency, and this is contingent on their skills and competence. Furthermore, managers routinely called upon paramedics to lead in their absence. It is shown here that, although informally enacted, paramedics view leadership as a necessary competency for clinical practice. We argue that leadership development of paramedics must begin during their formal education and training as part of the core curriculum. As well, direct managers can promote an environment of shared leadership and encourage paramedics to practice leadership with quality of patient service in mind.

  12. MGDS: Free, on-line, cutting-edge tools to enable the democratisation of geoscience data

    NASA Astrophysics Data System (ADS)

    Goodwillie, A. M.; Ryan, W. B.; O'Hara, S.; Ferrini, V.; Arko, R. A.; Coplan, J.; Chan, S.; Carbotte, S. M.; Nitsche, F. O.; Bonczkowski, J.; Morton, J. J.; Weissel, R.; Leung, A.

    2010-12-01

    The availability of user-friendly, effective cyber-information resources for accessing and manipulating geoscience data has grown rapidly in recent years. Based at Lamont-Doherty Earth Observatory the MGDS group has developed a number of free tools that have wide application across the geosciences for both educators and researchers. A simple web page (http://www.marine-geo.org/) allows users to search for and download many types of data by key word, geographical region, or published citation. The popular Create Maps and Grids function and the downloadable Google Earth-compatible KML files appeal to a wide user base. MGDS MediaBank galleries (http://media.marine-geo.org/) enable users to view and download compelling images that are purposefully selected for their educational value from NSF-funded field programs. GeoMapApp (http://www.geomapapp.org), a free map-based interactive tool that works on any machine, is increasingly being adopted across a broad suite of users from middle school students to university researchers. GeoMapApp allows users to plot, manipulate and present data in an intuitive geographical reference frame. GeoMapApp offers a convenient way to explore the wide range of built-in data sets, to quickly generate maps and images that aid visualisation and, when importing their own gridded and tabular data sets, to access the same rich built-in functionality. A user guide, short multi-media tutorials, and webinar are available on-line. The regularly-updated Global Multi-Resolution Topography (GMRT) Synthesis is used as the default GeoMapApp base map and is an increasingly popular means to rapidly create location maps. Additionally, the layer manager offers a fast way to overlay and compare multiple data sets and is augmented by the ability to alter layer transparency so that underlying layers become visible. Examples of GeoMapApp built-in data sets include high-resolution land topography and ocean floor bathymetry derived from satellite and multi

  13. Formulas for the Supersonic Loading, Lift, and Drag of Flat Swept-Back Wings with Leading Edges Behind the Mach Line

    NASA Technical Reports Server (NTRS)

    Cohen, Doris

    1951-01-01

    The method of superposition of linearized conical flows has been applied to the calculation of the aerodynamic properties, in supersonic flight, of thin flat, swept-back wings at an angle of attack. The wings are assumed to have rectilinear plan forms, with tips parallel to the stream, and to taper in the conventional sense. The investigation covers the moderately supersonic speed range where the Mach lines from the leading-edge apex lie ahead of the wing. The trailing edge may lie ahead of or behind the Mach lines from its apex. The case in which the Mach cone from one tip intersects the other tip is not treated. Formulas are obtained for the load distribution, the total lift, and the drag due to lift. For the cases in which the trailing edge is outside the Mach cone from its apex the formulas are complete. For wings with both leading and trailing edges behind their respective Mach lines, a degree of approximation is necessary. Charts of some of the functions derived are included to facilitate computing, and several examples are worked out in outline.

  14. The Rough Edges: Community, Art and History

    ERIC Educational Resources Information Center

    Jeffers, Alison

    2010-01-01

    In September 2008 the author created an encounter between herself and Rick Walker, the Director of Cartwheel Arts, a small community arts company in Rochdale, in the North West of England. As one of the three founding workers of what was then Cartwheel Community Arts in 1984, she hoped to create a conversation which recollected or traced some of…

  15. Advanced CD-SEM metrology for pattern roughness and local placement of lamellar DSA

    NASA Astrophysics Data System (ADS)

    Kato, Takeshi; Sugiyama, Akiyuki; Ueda, Kazuhiro; Yoshida, Hiroshi; Miyazaki, Shinji; Tsutsumi, Tomohiko; Kim, JiHoon; Cao, Yi; Lin, Guanyang

    2014-04-01

    Directed self-assembly (DSA) applying chemical epitaxy is one of the promising lithographic solutions for next generation semiconductor device manufacturing. We introduced Fingerprint Edge Roughness (FER) as an index to evaluate edge roughness of non-guided lamella finger print pattern, and found its correlation with the Line Edge Roughness (LER) of the lines assembled on the chemical guiding patterns. In this work, we have evaluated both FER and LER at each process steps of the LiNe DSA flow utilizing PS-b-PMMA block copolymers (BCP) assembled on chemical template wafers fabricated with Focus Exposure Matrix (FEM). As a result, we found the followings. (1) Line widths and space distances of the DSA patterns slightly differ to each other depending on their relative position against the chemical guide patterns. Appropriate condition that all lines are in the same dimensions exists, but the condition is not always same for the spaces. (2) LER and LWR (Line Width Roughness) of DSA patterns neither depend on width nor LER of the guide patterns. (3) LWR of DSA patterns are proportional to the width roughness of fingerprint pattern. (4) FER is influenced not only by the BCP formulation, but also by its film thickness. We introduced new methods to optimize the BCP formulation and process conditions by using FER measurement and local CD valuation measurement. Publisher's Note: This paper, originally published on 2 April 2014, was replaced with a corrected/revised version on 14 May 2014. If you downloaded the original PDF but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance.

  16. Review of Hydraulic Roughness Scales in the Fully Rough Regime

    DTIC Science & Technology

    2010-04-01

    Bowden and Davison 11 to be used with the 1978 ITTC perfor - mance prediction line for ship resistance. This coefficient is a function of the mean...con- siderations, along with a lack of accurate hull roughness measure- ments, led the ITTC Specialist Committee on Powering Perfor - mance Prediction...roughness length. For the two layer approach, the wall layer model is patched to the outer layer model by modifying the k boundary condition in the k− model

  17. Research of Surface Roughness Anisotropy

    NASA Astrophysics Data System (ADS)

    Bulaha, N.; Rudzitis, J.; Lungevics, J.; Linins, O.; Krizbergs, J.

    2017-04-01

    The authors of the paper have investigated surfaces with irregular roughness for the purpose of determination of roughness spacing parameters perpendicularly to machining traces - RSm1 and parallel to them - RSm2, as well as checking the relationship between the surface anisotropy coefficient c and surface aspect ratio Str from the standard LVS EN ISO 25178-2. Surface roughness measurement experiments with 11 surfaces show that measuring equipment values of mean spacing of profile irregularities in the longitudinal direction are not reliable due to the divergence of surface mean plane and roughness profile mean line. After the additional calculations it was stated that parameter Str can be used for determination of parameter RSm2 and roughness anisotropy evaluation for grinded, polished, friction surfaces and other surfaces with similar characteristics.

  18. Mask roughness and its implications for LER at the 22- and 16-nm nodes

    SciTech Connect

    Naulleau, Patrick; George, Simi A.; McClinton, Brittany M.

    2010-02-16

    Line-edge roughness (LER) remains the most significant challenge facing the development of extreme ultraviolet (EUV) resist. The mask, however, has been found to be a significant contributor to image-plane LER. This has long been expected based on modeling and has more recently been demonstrated experimentally. Problems arise from both mask-absorber LER as well as mask multilayer roughness leading to random phase variations in the reflected beam and consequently speckle. Understanding the implications this has on mask requirements for the 22-nm half pitch node and below is crucial. Modeling results indicate a replicated surface roughness (RSR) specification of 50 pm and a ruthenium capping layer roughness specification of 440 pm. Moreover, modeling indicates that it is crucial to achieve the current ITRS specifications for mask absorber LER which is significantly smaller than current capabilities.

  19. Roughness and uniformity improvements on self-aligned quadruple patterning technique for 10nm node and beyond by wafer stress engineering

    NASA Astrophysics Data System (ADS)

    Liu, Eric; Ko, Akiteru; O'Meara, David; Mohanty, Nihar; Franke, Elliott; Pillai, Karthik; Biolsi, Peter

    2017-05-01

    Dimension shrinkage has been a major driving force in the development of integrated circuit processing over a number of decades. The Self-Aligned Quadruple Patterning (SAQP) technique is widely adapted for sub-10nm node in order to achieve the desired feature dimensions. This technique provides theoretical feasibility of multiple pitch-halving from 193nm immersion lithography by using various pattern transferring steps. The major concept of this approach is to a create spacer defined self-aligned pattern by using single lithography print. By repeating the process steps, double, quadruple, or octuple are possible to be achieved theoretically. In these small architectures, line roughness control becomes extremely important since it may contribute to a significant portion of process and device performance variations. In addition, the complexity of SAQP in terms of processing flow makes the roughness improvement indirective and ineffective. It is necessary to discover a new approach in order to improve the roughness in the current SAQP technique. In this presentation, we demonstrate a novel method to improve line roughness performances on 30nm pitch SAQP flow. We discover that the line roughness performance is strongly related to stress management. By selecting different stress level of film to be deposited onto the substrate, we can manipulate the roughness performance in line and space patterns. In addition, the impact of curvature change by applied film stress to SAQP line roughness performance is also studied. No significant correlation is found between wafer curvature and line roughness performance. We will discuss in details the step-by-step physical performances for each processing step in terms of critical dimension (CD)/ critical dimension uniformity (CDU)/line width roughness (LWR)/line edge roughness (LER). Finally, we summarize the process needed to reach the full wafer performance targets of LWR/LER in 1.07nm/1.13nm on 30nm pitch line and space pattern.

  20. Fluids confined in wedges and by edges: Virial series for the line-thermodynamic properties of hard spheres

    SciTech Connect

    Urrutia, Ignacio

    2014-12-28

    This work is devoted to analyze the relation between the thermodynamic properties of a confined fluid and the shape of its confining vessel. Recently, new insights in this topic were found through the study of cluster integrals for inhomogeneous fluids that revealed the dependence on the vessel shape of the low density behavior of the system. Here, the statistical mechanics and thermodynamics of fluids confined in wedges or by edges is revisited, focusing on their cluster integrals. In particular, the well known hard sphere fluid, which was not studied in this framework so far, is analyzed under confinement and its thermodynamic properties are analytically studied up to order two in the density. Furthermore, the analysis is extended to the confinement produced by a corrugated wall. These results rely on the obtained analytic expression for the second cluster integral of the confined hard sphere system as a function of the opening dihedral angle 0 < β < 2π. It enables a unified approach to both wedges and edges.

  1. Fluids confined in wedges and by edges: virial series for the line-thermodynamic properties of hard spheres.

    PubMed

    Urrutia, Ignacio

    2014-12-28

    This work is devoted to analyze the relation between the thermodynamic properties of a confined fluid and the shape of its confining vessel. Recently, new insights in this topic were found through the study of cluster integrals for inhomogeneous fluids that revealed the dependence on the vessel shape of the low density behavior of the system. Here, the statistical mechanics and thermodynamics of fluids confined in wedges or by edges is revisited, focusing on their cluster integrals. In particular, the well known hard sphere fluid, which was not studied in this framework so far, is analyzed under confinement and its thermodynamic properties are analytically studied up to order two in the density. Furthermore, the analysis is extended to the confinement produced by a corrugated wall. These results rely on the obtained analytic expression for the second cluster integral of the confined hard sphere system as a function of the opening dihedral angle 0 < β < 2π. It enables a unified approach to both wedges and edges.

  2. The broad emission-line region: the confluence of the outer accretion disc with the inner edge of the dusty torus

    NASA Astrophysics Data System (ADS)

    Goad, M. R.; Korista, K. T.; Ruff, A. J.

    2012-11-01

    We have investigated the observational characteristics of a class of broad emission line region (BLR) geometries that connect the outer accretion disc with the inner edge of the dusty toroidal obscuring region (TOR). We suggest that the BLR consists of photoionized gas of densities which allow for efficient cooling by ultraviolet (UV)/optical emission lines and of incident continuum fluxes which discourage the formation of grains, and that such gas occupies the range of distance and scale height between the continuum-emitting accretion disc and the dusty TOR. As a first approximation, we assume a population of clouds illuminated by ionizing photons from the central source, with the scale height of the illuminated clouds growing with increasing radial distance, forming an effective surface of a 'bowl'. Observer lines of sight which peer into the bowl lead to a Type 1 active galactic nuclei (AGN) spectrum. We assume that the gas dynamics are dominated by gravity, and we include in this model the effects of transverse Doppler shift (TDS), gravitational redshift (GR) and scale-height-dependent macroturbulence. Our simple model reproduces many of the commonly observed phenomena associated with the central regions of AGN, including (i) the shorter than expected continuum-dust delays (geometry), (ii) the absence of response in the core of the optical recombination lines on short time-scales (geometry/photoionization), (iii) an enhanced redwing response on short time-scales (GR and TDS), (iv) the observed differences between the delays for high- and low-ionization lines (photoionization), (v) identifying one of the possible primary contributors to the observed line widths for near face-on systems even for purely transverse motion (GR and TDS), (vi) a mechanism responsible for producing Lorentzian profiles (especially in the Balmer and Mg II emission lines) in low-inclination systems (turbulence), (vii) the absence of significant continuum-emission-line delays between the

  3. A possibility of avoiding surface roughness due to insects

    NASA Technical Reports Server (NTRS)

    Wortmann, F. X.

    1984-01-01

    Discussion of a method for eliminating turbulence caused by the formation of insect roughness upon the leading edges and fuselage, particularly in aircraft using BLC. The proposed technique foresees the use of elastic surfaces on which insect roughness cannot form. The operational characteristics of highly elastic rubber surface fastened to the wing leading edges and fuselage edges are examined. Some preliminary test results are presented. The technique is seen to be advantageous primarily for short-haul operations.

  4. A multi-directional and multi-scale roughness filter to detect lineament segments on digital elevation models - analyzing spatial objects in R

    NASA Astrophysics Data System (ADS)

    Baumann, Sebastian; Robl, Jörg; Wendt, Lorenz; Willingshofer, Ernst; Hilberg, Sylke

    2016-04-01

    Automated lineament analysis on remotely sensed data requires two general process steps: The identification of neighboring pixels showing high contrast and the conversion of these domains into lines. The target output is the lineaments' position, extent and orientation. We developed a lineament extraction tool programmed in R using digital elevation models as input data to generate morphological lineaments defined as follows: A morphological lineament represents a zone of high relief roughness, whose length significantly exceeds the width. As relief roughness any deviation from a flat plane, defined by a roughness threshold, is considered. In our novel approach a multi-directional and multi-scale roughness filter uses moving windows of different neighborhood sizes to identify threshold limited rough domains on digital elevation models. Surface roughness is calculated as the vertical elevation difference between the center cell and the different orientated straight lines connecting two edge cells of a neighborhood, divided by the horizontal distance of the edge cells. Thus multiple roughness values depending on the neighborhood sizes and orientations of the edge connecting lines are generated for each cell and their maximum and minimum values are extracted. Thereby negative signs of the roughness parameter represent concave relief structures as valleys, positive signs convex relief structures as ridges. A threshold defines domains of high relief roughness. These domains are thinned to a representative point pattern by a 3x3 neighborhood filter, highlighting maximum and minimum roughness peaks, and representing the center points of lineament segments. The orientation and extent of the lineament segments are calculated within the roughness domains, generating a straight line segment in the direction of least roughness differences. We tested our algorithm on digital elevation models of multiple sources and scales and compared the results visually with shaded relief map

  5. Solution of the wave equation for open surfaces involving a line integral over the edge. [for supersonic propeller noise prediction

    NASA Technical Reports Server (NTRS)

    Farassat, F.

    1984-01-01

    A simple mathematical model of a stationary source distribution for the supersonic-propeller noise-prediction formula of Farassat (1983) is developed to test the validity of the formula solutions. The conventional thickness source term is used in place of the Isom thickness formula; the relative importance of the line and surface integrals in the solutions is evaluated; and the numerical results are compared with those obtained with a conventional retarded-time solution in tables. Good agreement is obtained over elevation angles from 10 to 90 deg, and the line-integral contribution is found to be significant at all elevation angles and of the same order of magnitude as the surface-integral contribution at angles less than 30 deg. The amplitude-normalized directivity patterns for the four cases computed (x = 1.5 or 10; k = 5.0 or 50) are presented graphically.

  6. Light Scattering from Rough Surfaces

    DTIC Science & Technology

    1994-08-17

    us (V. Ruiz Cortes) was supported by a CONACYT and CICESE scholarship. 5. REFERENCES I.-K.A. O’Donnell and E.R. Mdndez, "Experimental study of...Calculated variation of scattenng for increasing roughness. The angle of incidence is 800. The solid line is (DAJA45-90-C-0026). VRC thanks CONACYT and for a

  7. A Minor Modification of Leading Edge Discriminator Circuitry with a Delay Line for Baseline Restoration of Scintillation Detectors

    SciTech Connect

    Izumi, N

    2003-05-27

    Multi-channel neutron time-of-flight detector arrays LaNSA, T-ion, Medusa, and Mandala, have been used for neutron spectroscopy in inertial confinement fusion experiments. These multi-channel neutron detector arrays consist of many identical scintillation detectors (842 {approx} 1024 channel), data acquisition electronics (discriminators, time-to digital converters, and controller). Each detector element is operated in neutron counting mode. Time-of-flight of individual detected neutrons are recorded by time to digital converters. The energy of each detected neutrons is determined from its time-of-flight. The accurate time measurement ({Delta}t {approx} 0.5 ns) and straightforward statistical features of the data obtained with these systems provides good integrity and reliability. The elements detector used in these systems are organic scintillators coupled with photo multiplier tubes. A scintillation detector operated in particle-counting mode requires finite recovery time after each detection event. The recovery time is determined by the time responses of scintillators, photo multiplier tubes, and the dead times of following discriminators and time-to digital converters. The harsh gamma ray background environment of fast ignitor experiments requires detectors that have fast recovery times. In high intensity laser experiments (I > 10{sup 19} W/cm{sup 2}), strong gamma ray bursts are produced by relativistic laser plasma interactions. Prior to the neutron signal, these strong gamma ray bursts hit the detectors and interfere with the detection of following neutron signals. In these situations, the recovery time of the system after preceding gamma ray bursts is determined mainly by the base line shift of the PMT signal (due to slower decay components of scintillators ''after glow''). Discriminators cannot detect following signal pulses until the proceeding burst decays below its threshold voltage. The base line shift caused by the after glow prolongs the recovery

  8. Cutting-edge CMP modeling for front-end-of-line (FEOL) and full stack hotspot detection for advanced technologies

    NASA Astrophysics Data System (ADS)

    Katakamsetty, Ushasree; Chee, Jiansheng Jansen; Li, Yongfu; Hui, Chiu Wing; Huang, Yaodong; de la Garza, Ernesto Gene

    2017-03-01

    As process technology scales down, the number of Chemical Mechanical Polishing (CMP) processes and steps used in chip manufacturing are increasing exponentially. Shrinking process margins increase the risk of excessive metal or oxide thickness or topography variations, causing potential yield problems such as dishing, erosion, resist lifting or printability issues. Present DFM CMP modeling and applications mainly focus on the hotspot detection and fixing methodology for the Back-End-Of-Line (BEOL) layers [1]. Today, the present methodology is no longer sufficient to eliminate all the CMP related manufacturing defects. There is a strong demand for STI, poly and contact silicon calibrated CMP models to predict and fix the related CMP hotspots. Shallow Trench Isolation (STI) and Poly CMP planarity is very critical in advanced technologies with Diffusion layer FIN structures and Replacement Metal Gate Process flow [2]. Gate uniformity after CMP will improve device performance, reduce CMP defects and increases the yield. Contact (Tungsten) CMP polishing is another important step that defines contact planarity, which will influence metal layer CMP planarization [3]. This paper will discuss design dependent CMP variations for STI, Poly and Contact CMP steps and showcase the importance of FEOL CMP modeling. We present the methodology for Silicon calibrated STI CMP, Poly and Contact CMP models and the applications of FEOL CMP models in CMP dishing and erosion hotspot analysis. We also present FEOL plus BEOL multi stack CMP simulations applications and provide design guidelines to fix CMP hotspots.

  9. High-throughput and non-destructive sidewall roughness measurement using 3-dimensional atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Hua, Yueming; Buenviaje-Coggins, Cynthia; Lee, Yong-ha; Park, Sang-il

    2012-03-01

    As the feature size of the semiconductor device is becoming increasingly smaller and the transistor has become three-dimensional (e.g. Fin-FET structure), a simple Line Edge Roughness (LER) is no longer sufficient for characterizing these devices. Sidewall Roughness (SWR) is now the more proper metric for these metrology applications. However, current metrology technologies, such as SEM and OCD, provide limited information on the sidewall of such small structures. The subject of this study is the sidewall roughness measurement with a three-dimensional Atomic Force Microscopy (AFM) using tilted Z scanner. This 3D AFM is based on a decoupled XY and Z scanning configuration, in which the Z scanner can be intentionally tilted to the side. A sharp conical tip is typically used for imaging, which provides high resolution capability on both the flat surfaces (top and bottom) and the steep sidewalls.

  10. Validity of the thin mask approximation in extreme ultraviolet mask roughness simulations

    SciTech Connect

    Naulleau, Patrick; George, Simi

    2011-01-26

    In the case of extreme ultraviolet (EUV) lithography, modeling has shown that reflector phase roughness on the lithographic mask is a significant concern due to the image plan speckle it causes and the resulting line-edge roughness on imaged features. Modeling results have recently been used to determine the requirements for future production worthy masks yielding the extremely stringent specification of 50 pm rms roughness. Owing to the scale of the problem in terms of memory requirements, past modeling results have all been based on the thin mask approximation. EUV masks, however, are inherently three dimensional in nature and thus the question arises as to the validity of the thin mask approximation. Here we directly compare image plane speckle calculation results using the fast two dimensional thin mask model to rigorous finite-difference time-domain results and find the two methods to be comparable.

  11. Analysis of a two row hydrostatic journal bearing with variable properties, inertia effects and surface roughness

    NASA Technical Reports Server (NTRS)

    Braun, M. J.; Adams, M. L.; Mullen, R. L.

    1985-01-01

    A computer algorithm for simulation of hydrostatic journal bearing pressure-flow behavior has been generated. The effects taken into account are inertia, cavitation, variable properties (isothermal bearing) and roughness. The program has been specifically tailored for simulation of the hybrid bearing of the cryogenic turbopumps of the main shuttle engine. Due to the high pressure (515 psia) of the supply line no cavitation has been found. The influence of the roughness effects have been found to become important only when the surface-roughness order of magnitude is comparable with that of the bearing clearance itself. Pocket edge inertia and variable properties have been found to have quite an important influence upon the pocket pressure, field pressure distribution and lubricant mass flow.

  12. Analysis of a two row hydrostatic journal bearing with variable properties, inertia effects and surface roughness

    NASA Technical Reports Server (NTRS)

    Braun, M. J.; Adams, M. L.; Mullen, R. L.

    1985-01-01

    A computer algorithm for simulation of hydrostatic journal bearing pressure-flow behavior has been generated. The effects taken into account are inertia, cavitation, variable properties (isothermal bearing) and roughness. The program has been specifically tailored for simulation of the hybrid bearing of the cryogenic turbopumps of the main shuttle engine. Due to the high pressure (515 psia) of the supply line no cavitation has been found. The influence of the roughness effects have been found to become important only when the surface-roughness order of magnitude is comparable with that of the bearing clearance itself. Pocket edge inertia and variable properties have been found to have quite an important influence upon the pocket pressure, field pressure distribution and lubricant mass flow.

  13. Edge and coupled core/edge transport modeling in tokamak

    SciTech Connect

    Pearlstein, L D; Casper, T A; Cohen, R H; LoDestro, L L; Mattor, N; Porter, G D; Rensink, M E; Rognlien, T D; Ryutov, D D; Scott, H A; Wan, A

    1998-10-14

    Recent advances in the theory and modelling of tokamak edge, scrape-off-layer and divertor plasmas are described. The effects of the poloidal ExB drift on inner/outer divertor-plate asymmetries within a 1D analysis are shown to be in good agreement with experimental observations; above a critical v ExB, the model predicts transitions to supersonic SOL flow at the inboard midplane. Two-dimensional simulations show the importance of ExB flow in the private-flux region and B-drift effects. A theory of rough plasma-facing surfaces is given, and interesting effects, some traveling back up the magnetic field-lines to the SOL plasma, are predicted. The parametric dependence of detached-plasma states in slab geometry has been explored; with sufficient pumping, the location of the ionization front can be controlled; otherwise only fronts at the plate or the X-point are stable. Studies with a more accurate Monte-Carlo neutrals model and a detailed non-LTE radiation-transport code indicate various effects are important for quantitative rnodelling. Long-lived oscillatory UEDGE solutions in both ITER and DIII-D are reported. Detailed simulations of the DIII-D core and edge are presented; impurity and plasma flow are shown to be well modelled with UEDGE, and the roles of impurity and neutral transport in the edge and SOL are discussed.

  14. Transgenic cry1C(⁎) gene rough rice line T1C-19 does not change the host preferences of the non-target stored product pest, Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae), and its parasitoid wasp, Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae).

    PubMed

    Sun, Xiao; Yan, Miao-Jun; Zhang, Aijun; Wang, Man-Qun

    2015-10-01

    Rough rice grains are often stored for extended periods before they are used or consumed. However, during storage, the rough rice is vulnerable to insect infestation, resulting in significant economic loss. Previous studies have shown that volatiles cues, physical characteristics, and taste chemicals on the grains could be the important key behavior factors for storage insect pests to locate the hosts and select oviposition sites. It is also well known that the transgenic Bt rough rice line T1C-19, which expresses a cry1C(⁎) gene has a high resistance to Lepidoptera pests. However, there were no evidences to show the consequences of host preference for non-target insect pests after growing Bt transgenic rice. In this study, the potential key factors of Bt rough rice were investigated for their impacts on the behaviors of non-target pest lesser grain borer Rhyzopertha dominica, the main weevil pest of grain and its parasitic wasps Anisopteromalus calandrae, the natural enemy of the beetle. Both electronic nose and electronic tongue analyses showed that the parameters of Bt rough rice were analogous to those of the non-Bt rough rice. The volatile profiles of Bt and non-Bt rough rice examined by gas chromatographic mass spectrometry (GC-MS) were similar. For most volatile compounds, there were no significantly quantitative differences in compound quantities between Bt and non-Bt rough rice. The densities of sclereids and trichomes on the rough rice husk surface were statistically equal in Bt and non-Bt rough rice. The non-target pest, R. dominica, and its parasitoid wasp, A. calandrae, were attracted to both rough rice and could not distinguish the transgenic T1C-19 from the isogenic rough rice. These results demonstrated that Bt rough rice has no negative impacts on the host preference behaviors of non-target stored product pest R. dominica and its parasitoid A. calandrae.

  15. Edge detection by nonlinear dynamics

    SciTech Connect

    Wong, Yiu-fai

    1994-07-01

    We demonstrate how the formulation of a nonlinear scale-space filter can be used for edge detection and junction analysis. By casting edge-preserving filtering in terms of maximizing information content subject to an average cost function, the computed cost at each pixel location becomes a local measure of edgeness. This computation depends on a single scale parameter and the given image data. Unlike previous approaches which require careful tuning of the filter kernels for various types of edges, our scheme is general enough to be able to handle different edges, such as lines, step-edges, corners and junctions. Anisotropy in the data is handled automatically by the nonlinear dynamics.

  16. Faster magnetic walls in rough wires.

    PubMed

    Nakatani, Yoshinobu; Thiaville, André; Miltat, Jacques

    2003-08-01

    In some magnetic devices that have been proposed, the information is transmitted along a magnetic wire of submicrometre width by domain wall (DW) motion. The speed of the device is obviously linked to the DW velocity, and measured values up to 1 km x s(-1) have been reported in moderate fields. Although such velocities were already reached in orthoferrite crystal films with a high anisotropy, the surprise came from their observation in the low-anisotropy permalloy. We have studied, by numerical simulation, the DW propagation in such samples, and observed a very counter-intuitive behaviour. For perfect samples (no edge roughness), the calculated velocity increased with field up to a threshold, beyond which it abruptly decreased--a well-known phenomenon. However, for rough strip edges, the velocity breakdown was found to be suppressed. We explain this phenomenon, and propose that roughness should rather be engineered than avoided when fabricating nanostructures for DW propagation.

  17. Anisotropy in the wetting of rough surfaces.

    PubMed

    Chen, Yong; He, Bo; Lee, Junghoon; Patankar, Neelesh A

    2005-01-15

    Surface roughness amplifies the water-repellency of hydrophobic materials. If the roughness geometry is, on average, isotropic then the shape of a sessile drop is almost spherical and the apparent contact angle of the drop on the rough surface is nearly uniform along the contact line. If the roughness geometry is not isotropic, e.g., parallel grooves, then the apparent contact angle is no longer uniform along the contact line. The apparent contact angles observed perpendicular and parallel to the direction of the grooves are different. A better understanding of this problem is critical in designing rough superhydrophobic surfaces. The primary objective of this work is to determine the mechanism of anisotropic wetting and to propose a methodology to quantify the apparent contact angles and the drop shape. We report a theoretical and an experimental study of wetting of surfaces with parallel groove geometry.

  18. The impact of geometric non-linearities on the fatigue analysis of trailing edge bond lines in wind turbine rotor blades

    NASA Astrophysics Data System (ADS)

    Noever Castelos, Pablo; Balzani, Claudio

    2016-09-01

    The accurate prediction of stress histories for the fatigue analysis is of utmost importance for the design process of wind turbine rotor blades. As detailed, transient, and geometrically non-linear three-dimensional finite element analyses are computationally weigh too expensive, it is commonly regarded sufficient to calculate the stresses with a geometrically linear analysis and superimpose different stress states in order to obtain the complete stress histories. In order to quantify the error from geometrically linear simulations for the calculation of stress histories and to verify the practical applicability of the superposition principal in fatigue analyses, this paper studies the influence of geometric non-linearity in the example of a trailing edge bond line, as this subcomponent suffers from high strains in span-wise direction. The blade under consideration is that of the IWES IWT-7.5-164 reference wind turbine. From turbine simulations the highest edgewise loading scenario from the fatigue load cases is used as the reference. A 3D finite element model of the blade is created and the bond line fatigue assessment is performed according to the GL certification guidelines in its 2010 edition, and in comparison to the latest DNV GL standard from end of 2015. The results show a significant difference between the geometrically linear and non-linear stress analyses when the bending moments are approximated via a corresponding external loading, especially in case of the 2010 GL certification guidelines. This finding emphasizes the demand to reconsider the application of the superposition principal in fatigue analyses of modern flexible rotor blades, where geometrical nonlinearities become significant. In addition, a new load application methodology is introduced that reduces the geometrically non-linear behaviour of the blade in the finite element analysis.

  19. Effective field model of roughness in magnetic nano-structures

    SciTech Connect

    Lepadatu, Serban

    2015-12-28

    An effective field model is introduced here within the micromagnetics formulation, to study roughness in magnetic structures, by considering sub-exchange length roughness levels as a perturbation on a smooth structure. This allows the roughness contribution to be separated, which is found to give rise to an effective configurational anisotropy for both edge and surface roughness, and accurately model its effects with fine control over the roughness depth without the explicit need to refine the computational cell size to accommodate the roughness profile. The model is validated by comparisons with directly roughened structures for a series of magnetization switching and domain wall velocity simulations and found to be in excellent agreement for roughness levels up to the exchange length. The model is further applied to vortex domain wall velocity simulations with surface roughness, which is shown to significantly modify domain wall movement and result in dynamic pinning and stochastic creep effects.

  20. A model for rough wall turbulent heating and skin friction

    NASA Astrophysics Data System (ADS)

    Finson, M. L.

    1982-01-01

    A Reynolds stress model for turbulent boundary layers on rough walls is used to investigate the effects of roughness character and compressibility. The flow around roughness elements is treated as form drag. A method is presented for deriving the required roughness shape and spacing from profiometer surface measurements. Calculations based on the model compare satisfactorily with low speed data on roughness character and hypersonic measurements with grit roughness. The computer model is exercised systematically over a wide range of parameters to derive a practical scaling law for the equivalent roughness. In contrast to previous correlations, for most roughness element shapes the effective roughness does not show a pronounced maximum as the element spacing decreases. The effect of roughness tends to be reduced with increasing edge Mach number, primarily due to decreasing density in the vicinity of the roughness elements. It is further shown that the required roughness Reynolds number for fully rough behavior increases with increasing Mach number, explaining the small roughness effects observed in some hypersonic tests.

  1. Understanding EUV mask blank surface roughness induced LWR and associated roughness requirement

    SciTech Connect

    Yan, Pei-Yang; Zhang, Guojing; Gullickson, Eric M.; Goldberg, Kenneth A.; Benk, Markus P.

    2015-03-01

    Extreme ultraviolet lithography (EUVL) mask multi-layer (ML) blank surface roughness specification historically comes from blank defect inspection tool requirement. Later, new concerns on ML surface roughness induced wafer pattern line width roughness (LWR) arise. In this paper, we have studied wafer level pattern LWR as a function of EUVL mask surface roughness via High-NA Actinic Reticle Review Tool. We found that the blank surface roughness induced LWR at current blank roughness level is in the order of 0.5nm 3σ for NA=0.42 at the best focus. At defocus of ±40nm, the corresponding LWR will be 0.2nm higher. Further reducing EUVL mask blank surface roughness will increase the blank cost with limited benefit in improving the pattern LWR, provided that the intrinsic resist LWR is in the order of 1nm and above.

  2. Mask roughness induced LER control and mitigation: aberrations sensitivity study and alternate illumination scheme

    SciTech Connect

    McClinton, Brittany M.; Naulleau, Patrick P.

    2011-03-11

    Here we conduct a mask-roughness-induced line-edge-roughness (LER) aberrations sensitivity study both as a random distribution amongst the first 16 Fringe Zernikes (for overall aberration levels of 0.25, 0.50, and 0.75nm rms) as well as an individual aberrations sensitivity matrix over the first 37 Fringe Zernikes. Full 2D aerial image modeling for an imaging system with NA = 0.32 was done for both the 22-nm and 16-nm half-pitch nodes on a rough mask with a replicated surface roughness (RSR) of 100 pm and a correlation length of 32 nm at the nominal extreme-ultraviolet lithography (EUVL) wavelength of 13.5nm. As the ideal RSR value for commercialization of EUVL is 50 pm and under, and furthermore as has been shown elsewhere, a correlation length of 32 nm of roughness on the mask sits on the peak LER value for an NA = 0.32 imaging optic, these mask roughness values and consequently the aberration sensitivity study presented here, represent a worst-case scenario. The illumination conditions were chosen based on the possible candidates for the 22-nm and 16-nm half-pitch nodes, respectively. In the 22-nm case, a disk illumination setting of {sigma} = 0.50 was used, and for the 16-nm case, crosspole illumination with {sigma} = 0.10 at an optimum offset of dx = 0 and dy = .67 in sigma space. In examining how to mitigate mask roughness induced LER, we considered an alternate illumination scheme whereby a traditional dipole's angular spectrum is extended in the direction parallel to the line-and-space mask absorber pattern to represent a 'strip'. While this illumination surprisingly provides minimal improvement to the LER as compared to several alternate illumination schemes, the overall imaging quality in terms of image-log-slope (ILS) and contrast is improved.

  3. Giant edge state splitting at atomically precise graphene zigzag edges

    PubMed Central

    Wang, Shiyong; Talirz, Leopold; Pignedoli, Carlo A.; Feng, Xinliang; Müllen, Klaus; Fasel, Roman; Ruffieux, Pascal

    2016-01-01

    Zigzag edges of graphene nanostructures host localized electronic states that are predicted to be spin-polarized. However, these edge states are highly susceptible to edge roughness and interaction with a supporting substrate, complicating the study of their intrinsic electronic and magnetic structure. Here, we focus on atomically precise graphene nanoribbons whose two short zigzag edges host exactly one localized electron each. Using the tip of a scanning tunnelling microscope, the graphene nanoribbons are transferred from the metallic growth substrate onto insulating islands of NaCl in order to decouple their electronic structure from the metal. The absence of charge transfer and hybridization with the substrate is confirmed by scanning tunnelling spectroscopy, which reveals a pair of occupied/unoccupied edge states. Their large energy splitting of 1.9 eV is in accordance with ab initio many-body perturbation theory calculations and reflects the dominant role of electron–electron interactions in these localized states. PMID:27181701

  4. LER control and mitigation: mask roughness induced LER

    SciTech Connect

    McClinton, Brittany; Naulleau, Patrick

    2011-02-21

    In the push towards commercialization of extreme-ultraviolet lithography (EUVL), meeting the stringent requirements for line-edge roughness (LER) is increasingly challenging. For the 22-nm half-pitch node and below, the ITRS requires under 1.2 nm LER. Much of this LER is thought to arise from three significant contributors: LER on the mask absorber pattern, LER from the resist, and LER from mask roughness induced speckle. The physical mechanism behind the last contributor is becoming clearer, but how it is affected by the presence of aberrations is less well understood. Here, we conduct a full 2D aerial image simulation analysis of aberrations sensitivities of mask roughness induced LER for the first 37 fringe zernikes. These results serve as a guideline for future LER aberrations control. In examining how to mitigate mask roughness induced LER, we next consider an alternate illumination scheme whereby a traditional dipole's angular spectrum is extended in the direction parallel to the line-and-space mask absorber pattern to represent a 'strip'. While this illumination surprisingly provides merely minimal improvement to the LER as several alternate illumination schemes, overall imaging quality in terms of ILS, NILS, and contrast is improved. While the 22-nm half-pitch node can tolerate significant aberrations from a mask roughness induced LER perspective, total aberration levels for the 16-nm half-pitch node need to be strictly capped at 0.25nm rms to meet the ITRS guidelines. An individual aberrations study for the first 37 fringe zernikes on the 16-nm half-pitch node at the 0.25nm rms level reveals a sensitivity to various forms of spherical aberrations (Z9 & Z25) and quadrafoil (Z28) in particular, under conventional crosspole illumination ({sigma} = 0.10). Compared to conventional dipole or crosspole illuminations, an extended dipole 'strip' illumination scheme offers a way to mitigate mask roughness induced LER, while still maintaining high imaging quality for

  5. A next generation processing system for edging and trimming

    Treesearch

    A. Lynn Abbott; Daniel L. Schmoldt; Philip A. Araman

    2000-01-01

    This paper describes a prototype scanning system that is being developed for the processing of rough hardwood lumber. The overall goal of the system is to automate the selection of cutting positions for the edges and ends of rough, green lumber. Such edge and trim cuts are typically performed at sawmills in an effort to increase board value prior to sale, and this...

  6. 46 CFR 42.13-30 - Lines to be used with the load line mark.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) The following load lines shall be used: (1) The summer load line indicated by the upper edge of the... indicated by the upper edge of a line marked W. (3) The winter North Atlantic load line indicated by the upper edge of a line marked WNA. (4) The tropical load line indicated by the upper edge of a line marked...

  7. 46 CFR 42.13-30 - Lines to be used with the load line mark.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...) The following load lines shall be used: (1) The summer load line indicated by the upper edge of the... indicated by the upper edge of a line marked W. (3) The winter North Atlantic load line indicated by the upper edge of a line marked WNA. (4) The tropical load line indicated by the upper edge of a line marked...

  8. Lines

    ERIC Educational Resources Information Center

    Mires, Peter B.

    2006-01-01

    National Geography Standards for the middle school years generally stress the teaching of latitude and longitude. There are many creative ways to explain the great grid that encircles our planet, but the author has found that students in his college-level geography courses especially enjoy human-interest stories associated with lines of latitude…

  9. Lines

    ERIC Educational Resources Information Center

    Mires, Peter B.

    2006-01-01

    National Geography Standards for the middle school years generally stress the teaching of latitude and longitude. There are many creative ways to explain the great grid that encircles our planet, but the author has found that students in his college-level geography courses especially enjoy human-interest stories associated with lines of latitude…

  10. Discrete Roughness Transition for Hypersonic Flight Vehicles

    NASA Technical Reports Server (NTRS)

    Berry, Scott A.; Horvath, Thomas J.

    2007-01-01

    The importance of discrete roughness and the correlations developed to predict the onset of boundary layer transition on hypersonic flight vehicles are discussed. The paper is organized by hypersonic vehicle applications characterized in a general sense by the boundary layer: slender with hypersonic conditions at the edge of the boundary layer, moderately blunt with supersonic, and blunt with subsonic. This paper is intended to be a review of recent discrete roughness transition work completed at NASA Langley Research Center in support of agency flight test programs. First, a review is provided of discrete roughness wind tunnel data and the resulting correlations that were developed. Then, results obtained from flight vehicles, in particular the recently flown Hyper-X and Shuttle missions, are discussed and compared to the ground-based correlations.

  11. Measurement and Correlation of Ice Accretion Roughness

    NASA Technical Reports Server (NTRS)

    Anderson, David N.; Hentschel, Daniel B.; Ruff, Gary A.

    2003-01-01

    Measurements were taken of the roughness characteristics of ice accreted on NACA 0012 airfoils in the NASA Glenn Icing Research Tunnel (IRT). Tests were conducted with size scaled, using models with chords of 26.7, 53.3, and 80.0 cm, and with liquid-water content scaled, both according to previously-tested scaling methods. The width of the smooth zone which forms on either side of the leading edge of the airfoil and the diameter of the roughness elements are presented in non-dimensional form as functions of the accumulation parameter. The smooth-zone width was found to decrease with increasing accumulation parameter. The roughness-element diameter increased with accumulation parameter until a plateau was reached. This maximum diameter was about 0.06 times twice the model leading-edge radius. Neither smooth-zone width nor element diameter were affected by a change in freezing fraction from 0.2 to 0.4. Both roughness characteristics appeared to scale with model size and with liquid-water content.

  12. Edge Bioinformatics

    SciTech Connect

    Lo, Chien-Chi

    2015-08-03

    Edge Bioinformatics is a developmental bioinformatics and data management platform which seeks to supply laboratories with bioinformatics pipelines for analyzing data associated with common samples case goals. Edge Bioinformatics enables sequencing as a solution and forward-deployed situations where human-resources, space, bandwidth, and time are limited. The Edge bioinformatics pipeline was designed based on following USE CASES and specific to illumina sequencing reads. 1. Assay performance adjudication (PCR): Analysis of an existing PCR assay in a genomic context, and automated design of a new assay to resolve conflicting results; 2. Clinical presentation with extreme symptoms: Characterization of a known pathogen or co-infection with a. Novel emerging disease outbreak or b. Environmental surveillance

  13. Roughness and function

    NASA Astrophysics Data System (ADS)

    Thomas, T. R.

    2014-01-01

    A function map is used to locate applications of roughness in separation-velocity space. The importance of roughness in contact mechanics is demonstrated and versions of the plasticity index are introduced and compared. Case studies of roughness and function are presented from tribology and the life sciences. Tribological examples are taken from the automotive industry and include the manufacture of vehicle bodies, and drive train tribology, particularly cylinder liner, cam and gearbox friction and wear. From the life sciences, problems of prosthetic fixation and tribology are shown to depend on roughness. The interaction of haptics and surface finish is described and illustrated. A number of other areas of application are listed. Finally the likely future importance of structured surfaces is discussed.

  14. Surface Roughness Impedance

    SciTech Connect

    Stupakov, Gennady

    2000-12-21

    The next generation of linac-based free electron lasers will use very short bunches with a large peak current. For such beams, the impedance caused by submicron imperfections in the vacuum beam tube may generate an additional energy spread within the bunch. A review of two mechanisms of the roughness impedance is given with the emphasis on the importance of the high-aspect ratio property of the real surface roughness.

  15. Zigzag faceting and width refinement of graphene nanoribbons and nanoperforations via catalyzed edge-annealing on Cu(111)

    NASA Astrophysics Data System (ADS)

    Safron, Nathaniel S.; Choi, Jonathan W.; Kim, Myungwoong; Shin, Naechul; Gopalan, Padma; Arnold, Michael S.

    2015-12-01

    Top-down subtractive lithography has previously been used to pattern graphene nanostructures which lack ideal properties due to (1) limited resolution and (2) disordered edges. Here, we introduce a method to convert such disordered edges into relatively smooth zigzag edges via annealing on a Cu(111) substrate at ~950 °C. The Cu catalyzes the re-arrangement of graphene edge atoms to energetically favorable sites, inducing zigzag edge faceting. The dimensions of the graphene nanostructures can be increased, decreased, or held constant during the annealing by tuning the relative balance between growth and etching reactions, described by a fundamental growth rate equation. To demonstrate the flexibility of this method, we lithographically pattern graphene nanoribbons with zigzag or armchair orientations, or alternatively perforate graphene with circular holes, and then anneal these nanostructures to realize zigzag edge termination in each case, with nanostructure feature size tailored from 8 to 80 nm. The annealed nanostructures have smoother zigzag edges (~40% reduction in 1σ line edge roughness), and Raman spectroscopy confirms that they have lower edge disorder than top-down patterned samples.

  16. TRANSGENIC CRYLC* GENE ROUGH RICE LINE TIC-19 DOES NOT CHANGE THE HOST PREFERENCES OF THE NON-TARGET STORED PRODUCT PEST, RHYZOPERTHA DOMINICA (FABRICIUS) AND ITS PARASITOID WASP, ANISOPTEROMALUS CALANDRAE

    USDA-ARS?s Scientific Manuscript database

    Rough rice grains are often stored for extended periods before they are used or consumed. However, during storage, the rough rice is vulnerable to insect infestation, resulting in significant economic loss. Previous studies have shown that volatile cues, physical characteristics, and taste chemicals...

  17. Surface roughness measurement with laser triangulation

    NASA Astrophysics Data System (ADS)

    Bai, Fuzhong; Zhang, Xiaoyan; Tian, Chaoping

    2016-09-01

    A surface roughness measurement method is introduced in the paper, which is based on laser triangulation and digital image processing technique. In the measuring system, we use the line-structured light as light source, microscope lens and high-accuracy CCD sensor as displacement sensor as well. In addition, the working angle corresponding to the optimal sensitivity is considered in the optical structure design to improve the measuring accuracy. Through necessary image processing operation for the light strip image, such as center-line extraction with the barycenter algorithm, Gaussian filtering, the value of roughness is calculated. A standard planing surface is measured experimentally with the proposed method and the stylus method (Mitutoyo SJ-410) respectively. The profilograms of surface appearance are greatly similar in the shape and the amplitude to two methods. Also, the roughness statistics values are close. The results indicate that the laser triangulation with the line-structured light can be applied to measure the surface roughness with the advantages of rapid measurement and visualized display of surface roughness profile.

  18. Automatic scanning of rough hardwood lumber for edging and trimming

    Treesearch

    A. Lynn Abbott; Daniel L. Schmoldt; Philip A. Araman; Sang-Mook Lee

    2001-01-01

    Scanning of unplaned, green hardwood lumber has received relatively little attention in the research community. This has been due in part to the difficulty of clearly imaging fresh-cut boards whose fibrous surfaces mask many wood features. Nevertheless, it is important to improve lumber processing early in the manufacturing stream because much wood material is...

  19. Fault Roughness Records Strength

    NASA Astrophysics Data System (ADS)

    Brodsky, E. E.; Candela, T.; Kirkpatrick, J. D.

    2014-12-01

    Fault roughness is commonly ~0.1-1% at the outcrop exposure scale. More mature faults are smoother than less mature ones, but the overall range of roughness is surprisingly limited which suggests dynamic control. In addition, the power spectra of many exposed fault surfaces follow a single power law over scales from millimeters to 10's of meters. This is another surprising observation as distinct structures such as slickenlines and mullions are clearly visible on the same surfaces at well-defined scales. We can reconcile both observations by suggesting that the roughness of fault surfaces is controlled by the maximum strain that can be supported elastically in the wallrock. If the fault surface topography requires more than 0.1-1% strain, it fails. Invoking wallrock strength explains two additional observations on the Corona Heights fault for which we have extensive roughness data. Firstly, the surface is isotropic below a scale of 30 microns and has grooves at larger scales. Samples from at least three other faults (Dixie Valley, Mount St. Helens and San Andreas) also are isotropic at scales below 10's of microns. If grooves can only persist when the walls of the grooves have a sufficiently low slope to maintain the shape, this scale of isotropy can be predicted based on the measured slip perpendicular roughness data. The observed 30 micron scale at Corona Heights is consistent with an elastic strain of 0.01 estimated from the observed slip perpendicular roughness with a Hurst exponent of 0.8. The second observation at Corona Heights is that slickenlines are not deflected around meter-scale mullions. Yielding of these mullions at centimeter to meter scale is predicted from the slip parallel roughness as measured here. The success of the strain criterion for Corona Heights supports it as the appropriate control on fault roughness. Micromechanically, the criterion implies that failure of the fault surface is a continual process during slip. Macroscopically, the

  20. Saddle-node dynamics for edge detection

    SciTech Connect

    Wong, Y.F.

    1994-09-01

    The author demonstrates how the formulation of a nonlinear scale-space filter can be used for edge detection and junction analysis. By casting edge-preserving filtering in terms of maximizing information content subject to an average cost function, the computed cost at each pixel location becomes a local measure of edgeness. This computation depends on a single scale parameter and the given image data. Unlike previous approaches which require careful tuning of the filter kernels for various types of edges, this scheme is general enough to be able to handle different edges, such as lines, step edges, corners and junctions. Anisotropy in the data is handled automatically by the nonlinear dynamics.

  1. Subcellular fractionation of rough microsomes.

    PubMed

    Sabatini, David D

    2014-09-02

    When eukaryotic cells are homogenized, the rough endoplasmic reticula are converted into small vesicles, called rough microsomes. Strategies for the isolation of rough microsomes are introduced here, as are methods for evaluating the purity and intactness of an isolated rough microsomal fraction. © 2014 Cold Spring Harbor Laboratory Press.

  2. Surface Roughness Lengths

    DTIC Science & Technology

    1993-08-01

    m trees 110 - 170 Thom 1972 Pine forest - 20 m trees 128 DeBruin and Moore 1985 Forested plateau, rolling 120 - 130 Ming et al. 1983 Rolling terrain...H. A. R., and C. J. Moore , 1985 , "Zero-Plane Displacement and Roughness Length for Tall Vegetation, Derived from a Simple Mass Conservation

  3. ROUGH ROCK DEMONSTRATION SCHOOL.

    ERIC Educational Resources Information Center

    FORBES, JACK

    THE ROUGH ROCK DEMONSTRATION SCHOOL IS LOCATED IN NORTHEASTERN ARIZONA, WHERE THE NAVAJO LANGUAGE IS UNIVERSALLY SPOKEN BY THE NAVAJO PEOPLE. IT IS LOCATED ON A NAVAJO RESERVATION AND WAS DESIGNED AS A BIA EXPERIMENTAL SCHOOL TO SERVE 200 ELEMENTARY PUPILS, MOST OF WHOM ARE IN THE BOARDING SCHOOL SITUATION. AN OBJECTIVE OF THE SCHOOL IS TO GAIN…

  4. Identifying Changes in Snowpack Surface Roughness Characteristics

    NASA Astrophysics Data System (ADS)

    Fassnacht, S. R.; Corrao, M. V.; Deems, J. S.; Stednick, J. D.

    2006-12-01

    The flow of air over a surface is influenced by its roughness. The surface of a snowpack is smooth relative to the underlying ground surface. The relative roughness of the snowpack surface changes directionally, spatially, and temporally, due to deposition, erosion, and melt. To examine these changes in snowpack surface roughness at the microtopographic scale for a Northern Colorado site, the surface was photographed using a darker-coloured roughness board that was inserted into the snowpack so that a black (board) versus white (snow) contrast existed along the entire length of the board. The board was 1-m long and was inserted 11 times at 10-cm intervals to create a 1-m by 1-m mesh. The orientation of the boards was rotated 90 degrees to provide finer resolution data in perpendicular directions. For the 1-m boards, the pixel resolution was approximately 0.4 mm. To measure the snow grain scale, a crystal card was photographed and yielded a pixel resolution of approximately 0.1 mm. Incorporating image processing issues such as image contrast and brightness, the digital images were translated into individual lines. These lines were used to compute semi- variograms in log-log space, from which the magnitude of semi-variance, the fractal dimensions, and the scale break were computed. The semi-variogram characteristics were used to illustrate directional, spatial, and temporal changes in snowpack surface roughness.

  5. Optical waveguide end roughness in correlation to optical coupling

    NASA Astrophysics Data System (ADS)

    Kruse, Kevin; Riegel, Nick; Demars, Casey; Middlebrook, Christopher; Roggemann, Michael

    2012-01-01

    With the ever-increasing demand for board-to-board optical data communications, the correlation between waveguide surface end roughness and coupling losses must be thoroughly investigated. This study measures end roughness of siloxane polymer optical waveguides in terms of optical coupling losses. Siloxane Polymers from Dow Corning were used to fabricate 50 x 50 μm rectangular waveguides through photolithographic processes. Edge roughness was controlled through various grades of fiber-optic polishing films and then measured using interferometric microscopy (IFM). Controlled lab results are compared with industrial polishing techniques that are consistent with mass-production methods. Electromagnetic modeling revealed correlations between experimental and theoretical results.

  6. Edge Detection,

    DTIC Science & Technology

    1985-09-01

    PROJECT. T ASK0 Artificial Inteligence Laboratory AREA It WORK UNIT NUMBERS V 545 Technology Square ( Cambridge, HA 02139 I I* CONTOOL1LIN@4OFFICE NAME...ARD-A1t62 62 EDGE DETECTION(U) NASSACNUSETTS INST OF TECH CAMBRIDGE 1/1 ARTIFICIAL INTELLIGENCE LAB E C HILDRETH SEP 85 AI-M-8 N99SI4-8S-C-6595...used to carry out this analysis. cce~iO a N) ’.~" D LI’BL. P p ------------ Sj. t i MASSACHUSETTS INSTITUTE OF TECHNOLOGY i ARTIFICIAL INTELLIGENCE

  7. Estimation of basis line-integrals in a spectral distortion-modeled photon counting detector using low-rank approximation-based x-ray transmittance modeling: K-edge imaging application.

    PubMed

    Lee, Okkyun; Kappler, Steffen; Polster, Christoph; Taguchi, Katsuyuki

    2017-08-29

    Photon counting detectors (PCD) provide multiple energy-dependent measurements for estimating basis lineintegrals. However, the measured spectrum is distorted from the spectral response effect (SRE) via charge sharing, K-fluorescence emission, etc. Thus, in order to avoid bias and artifacts in images, the SRE needs to be compensated. For this purpose, we recently developed a computationally efficient three-step algorithm for PCD-CT without contrast agents by approximating smooth x-ray transmittance using low-order polynomial bases. It compensated the SRE by incorporating the SRE model in a linearized estimation process and achieved nearly the minimum variance and unbiased (MVU) estimator. In this paper, we extend the three-step algorithm to K-edge imaging applications by designing optimal bases using a low-rank approximation to model x-ray transmittances with arbitrary shapes (i.e., smooth without the K-edge or discontinuous with the K-edge). The bases can be used to approximate the x-ray transmittance and to linearize the PCD measurement modeling and then the three-step estimator can be derived as in the previous approach: Estimating the xray transmittance in the first step, estimating basis line-integrals including that of the contrast agent in the second step, and correcting for a bias in the third step. We demonstrate that the proposed method is more accurate and stable than the low-order polynomial-based approaches with extensive simulation studies using gadolinium for the K-edge imaging application. We also demonstrate that the proposed method achieves nearly MVU estimator, and is more stable than the conventional maximum likelihood estimator in high attenuation cases with fewer photon counts.

  8. Effect of shape of protrusions and roughness on the hydrophilicity of a surface

    NASA Astrophysics Data System (ADS)

    Chowdhury, Sheelan Sengupta; Pandey, Prithvi Raj; Kumar, Rajnish; Roy, Sudip

    2017-10-01

    We have investigated wetting of model rough surfaces made up of hydrophilic triangular and hexagonal pillars (protrusions). The surface roughnesses are altered by varying the area of the rough surface, the height of the pillars, and the surface interactions to the water. We have established a correlation between structure i.e., the shape of a pillar, which actually depends on the number of edges (due to shape), and the wetting phenomena. We have found that surface with higher number of edges repels water at lower roughness value. We explain the correlation by analyzing the variation of interactions energy components and density profiles of water on the structured surfaces.

  9. Micromagnetic modeling of domain wall motion in sub-100-nm-wide wires with individual and periodic edge defects

    NASA Astrophysics Data System (ADS)

    Dutta, S.; Siddiqui, S. A.; Currivan-Incorvia, J. A.; Ross, C. A.; Baldo, M. A.

    2015-12-01

    Reducing the switching energy of devices that rely on magnetic domain wall motion requires scaling the devices to widths well below 100 nm, where the nanowire line edge roughness (LER) is an inherent source of domain wall pinning. We investigate the effects of periodic and isolated rectangular notches, triangular notches, changes in anisotropy, and roughness measured from images of fabricated wires, in sub-100-nm-wide nanowires with in-plane and perpendicular magnetic anisotropy using micromagnetic modeling. Pinning fields calculated for a model based on discretized images of physical wires are compared to experimental measurements. When the width of the domain wall is smaller than the notch period, the domain wall velocity is modulated as the domain wall propagates along the wire. We find that in sub-30-nm-wide wires, edge defects determine the operating threshold and domain wall dynamics.

  10. Edge equilibrium code for tokamaks

    SciTech Connect

    Li, Xujing; Drozdov, Vladimir V.

    2014-01-15

    The edge equilibrium code (EEC) described in this paper is developed for simulations of the near edge plasma using the finite element method. It solves the Grad-Shafranov equation in toroidal coordinate and uses adaptive grids aligned with magnetic field lines. Hermite finite elements are chosen for the numerical scheme. A fast Newton scheme which is the same as implemented in the equilibrium and stability code (ESC) is applied here to adjust the grids.

  11. Surface roughness effects in elastohydrodynamic contacts

    NASA Technical Reports Server (NTRS)

    Tripp, J. H.; Hamrock, B. J.

    1985-01-01

    Surface roughness effects in full-film EHL contacts were studied. A flow factor modification to the Reynolds equation was applied to piezoviscous-elastic line contacts. Results for ensemble-averaged film shape, pressure distribution, and other mechanical quantities were obtained. Asperities elongated in the flow direction by a factor exceeding two decreased both film shape and pressure extrema at constant load; isotropic or transverse asperities increased these extrema. The largest effects are displayed by traction, which increased by over 5% for isotropic or transverse asperities and by slightly less for longitudinal roughness.

  12. A measuring system for surface roughness parameters

    NASA Astrophysics Data System (ADS)

    Han, Jinhong; Wang, Yunkai; Zhang, Xianfeng

    2006-11-01

    We designed a measurement and control system which can measure the surface roughness parameters with a Single Chip Micyoco (SCM) as its kernel. It uses an inductive transducer to pick up the data. The instrumental structure and the working principle are also introduced in this paper. The integrated hardware and software systems have been designed and improved. The prototype model was calibrated and the instrumental precision was analysed according to the measured data. In this system the surface roughness parameters can automatically be measured and controlled, such as data processing, determination of the reference line, disposal of the surface profile informations, display and print of the results etc.

  13. Theoretical investigations into the influence of the position of a breaking line on the tensile failure of flat, round, bevel-edged tablets using finite element methodology (FEM) and its practical relevance for industrial tablet strength testing.

    PubMed

    Podczeck, Fridrun; Newton, J Michael; Fromme, Paul

    2014-12-30

    Flat, round tablets may have a breaking ("score") line. Pharmacopoeial tablet breaking load tests are diametral in their design, and industrially used breaking load testers often have automatic tablet feeding systems, which position the tablets between the loading platens of the machine with the breaking lines in random orientation to the applied load. The aim of this work was to ascertain the influence of the position of the breaking line in a diametral compression test using finite element methodology (FEM) and to compare the theoretical results with practical findings using commercially produced bevel-edged, scored tablets. Breaking line test positions at an angle of 0°, 22.5°, 45°, 67.5° and 90° relative to the loading plane were studied. FEM results obtained for fully elastic and elasto-plastic tablets were fairly similar, but they highlighted large differences in stress distributions depending on the position of the breaking line. The stress values at failure were predicted to be similar for tablets tested at an angle of 45° or above, whereas at lower test angles the predicted breaking loads were up to three times larger. The stress distributions suggested that not all breaking line angles would result in clean tensile failure. Practical results, however, did not confirm the differences in the predicted breaking loads, but they confirmed differences in the way tablets broke. The results suggest that it is not advisable to convert breaking loads obtained on scored tablets into tablet tensile strength values, and comparisons between different tablets or batches should carefully consider the orientation of the breaking line with respect to the loading plane, as the failure mechanisms appear to vary. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Surface roughness and runoff

    NASA Astrophysics Data System (ADS)

    Szabó, Judit Alexandra; Szabó, Boglárka; Centeri, Csaba; Józsa, Sándor; Szalai, Zoltán; Jakab, Gergely

    2017-04-01

    Soil surface conditions changes dynamically during a precipitation event. The changes involve compaction, aggregate detachment and of course transportation by runoff or drop erosion. Those processes together have an effect on the transport process of the soil particles and aggregates, and influences the roughness of the soil surface as well. How does surface roughness have an effect on the aggregate and particle size distribution of the sediment? How does the sediment connectivity change from precipitation event to precipitation event? Beside the previous questions on of the main aim of the present research is to apply rainfall simulators for the built-up of a complex approach, rather than to concentrate only on one of two factors. Hence four types of sample were collected during the simulation experiment sequences: 1) photos were taken about the surface before and after the rain, in order to build digital surface models; 2) all the runoff and eroded sediment was collected; 3) soil loss due to drop erosion was also sampled separately; and 4) undisturbed crust samples were collected for thin section analyses. Though the runoff ratio was smaller than what, the preliminary results suggest that the sediment connectivity covered bigger area on crusty surface, than on a rough one. These ambiguous data may be connected to the soil crust development. J. A. Szabó wish to acknowledge the support of NTP-NFTÖ-16-0203. G. Jakab wish to acknowledge the support of János Bolyai Fellowship.

  15. Developing an edge-plasma diagnostic tool for the Globus-M tokamak based on measuring ratios of HeI lines

    NASA Astrophysics Data System (ADS)

    Timokhin, V. M.; Rykachevskii, A. I.; Miroshnikov, I. V.; Sergeev, V. Yu.; Kochergin, M. M.; Koval', A. N.; Mukhin, E. E.; Tolstyakov, S. Yu.; Voronin, A. V.

    2016-08-01

    A diagnostic technique that is based on measuring the ratios of neutral-helium line strengths has been developed for peripheral distributions of electron temperature and density of tokamak plasma. The main components of the technique are a four-channel filter-lens imaging polychromator (FLIP-4) and a Phantom Miro M110 high-speed camera for recording the images. The polychromator has been assembled, adjusted, and tested on an optical test bench. The optical system was installed on the spherical Globus-M tokamak. Some preliminary experiments were carried out. Images of the plasma-gun jet were obtained at neutralhelium lines.

  16. Turbulent boundary layer over roughness transition with variation in spanwise roughness length scale

    NASA Astrophysics Data System (ADS)

    Westerweel, Jerry; Tomas, Jasper; Eisma, Jerke; Pourquie, Mathieu; Elsinga, Gerrit; Jonker, Harm

    2016-11-01

    Both large-eddy simulations (LES) and water-tunnel experiments, using simultaneous stereoscopic PIV and LIF were done to investigate pollutant dispersion in a region where the surface changes from rural to urban roughness. This consists of rectangular obstacles where we vary the spanwise aspect ratio of the obstacles. A line source of passive tracer was placed upstream of the roughness transition. The objectives of the study are: (i) to determine the influence of the aspect ratio on the roughness-transition flow, and (ii) to determine the dominant mechanisms of pollutant removal from street canyons in the transition region. It is found that for a spanwise aspect ratio of 2 the drag induced by the roughness is largest of all considered cases, which is caused by a large-scale secondary flow. In the roughness transition the vertical advective pollutant flux is the main ventilation mechanism in the first three streets. Furthermore, by means of linear stochastic estimation the mean flow structure is identied that is responsible for exchange of the fluid between the roughness obstacles and the outer part of the boundary layer. Furthermore, it is found that the vertical length scale of this structure increases with increasing aspect ratio of the obstacles in the roughness region.

  17. 36. INTERIOR VIEW, NORTON GRINDER, TYPES USED TO GRIND ROUGH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    36. INTERIOR VIEW, NORTON GRINDER, TYPE-S USED TO GRIND ROUGH EDGES OFF THE FORGED TOOLS; NOTE OPERATOR IS FINISH GRINDING BLADE END OF A POST HOLE DIGGER AND TAMPING BAR - Warwood Tool Company, Foot of Nineteenth Street, Wheeling, Ohio County, WV

  18. Wane detection on rough lumber using surface approximation

    Treesearch

    Sang-Mook Lee; A. Lynn Abbott; Daniel L. Schmoldt

    2000-01-01

    The initial breakdown of hardwood logs into lumber produces boards with rough surfaces. These boards contain wane (missing wood due to the curved log exterior) that is removed by edge and trim cuts prior to sale. Because hardwood lumber value is determined using a combination of board size and quality, knowledge of wane position and defects is essential for selecting...

  19. Surface shape analysis of rough lumber for wane detection

    Treesearch

    Sang-Mook Lee; A. Lynn Abbott; Daniel L. Schmoldt

    2003-01-01

    The initial breakdown of hardwood logs into lumber produces boards with rough surfaces. These boards contain wane (missing wood that emanates from the log exterior, often containing residual bark) that is removed by edge and trim cuts prior to sale. Because hardwood lumber value is determined based on board size and quality, knowledge of wane position and defects is...

  20. Discrete Roughness Effects on Shuttle Orbiter at Mach 6

    NASA Technical Reports Server (NTRS)

    Berry, Scott A.; Hamilton, H. Harris, II

    2002-01-01

    Discrete roughness boundary layer transition results on a Shuttle Orbiter model in the NASA Langley Research Center 20-Inch Mach 6 Air Tunnel have been reanalyzed with new boundary layer calculations to provide consistency for comparison to other published results. The experimental results were previously obtained utilizing the phosphor thermography system to monitor the status of the boundary layer via global heat transfer images of the Orbiter windward surface. The size and location of discrete roughness elements were systematically varied along the centerline of the 0.0075-scale model at an angle of attack of 40 deg and the boundary layer response recorded. Various correlative approaches were attempted, with the roughness transition correlations based on edge properties providing the most reliable results. When a consistent computational method is used to compute edge conditions, transition datasets for different configurations at several angles of attack have been shown to collapse to a well-behaved correlation.

  1. Rough and Tumble Play 101

    ERIC Educational Resources Information Center

    Carlson, Frances

    2009-01-01

    Many people fear that play-fighting or rough and tumble play is the same as real fighting. There is also a fear that this rough play will become real fighting if allowed to continue. Most of all, parents and teachers fear that during the course of rough and tumble play a child may be hurt. To provide for and allow children to play rough without…

  2. Rough and Tumble Play 101

    ERIC Educational Resources Information Center

    Carlson, Frances

    2009-01-01

    Many people fear that play-fighting or rough and tumble play is the same as real fighting. There is also a fear that this rough play will become real fighting if allowed to continue. Most of all, parents and teachers fear that during the course of rough and tumble play a child may be hurt. To provide for and allow children to play rough without…

  3. Challenges in LER/CDU metrology in DSA: placement error and cross-line correlations

    NASA Astrophysics Data System (ADS)

    Constantoudis, Vassilios; Kuppuswamy, Vijaya-Kumar M.; Gogolides, Evangelos; Pret, Alessandro V.; Pathangi, Hari; Gronheid, Roel

    2016-03-01

    DSA lithography poses new challenges in LER/LWR metrology due to its self-organized and pitch-based nature. To cope with these challenges, a novel characterization approach with new metrics and updating the older ones is required. To this end, we focus on two specific challenges of DSA line patterns: a) the large correlations between the left and right edges of a line (line wiggling, rms(LWR)line correlations, i.e. the resemblance of wiggling fluctuations of nearby lines. The first is quantified by the Line Center Roughness whose low-frequency part is related to the local placement errors of device structures. For the second, we propose the c-factor correlation function which quantifies the strength of the correlations between lines versus their horizontal distance in pitches. Also, we define roughness and uniformity parameters for the pitch changes along and across lines. The proposed characterization approach is applied to the analysis of line/space patterns obtained with the Liu-Nealey (LiNe) flow (post PMMA removal and pattern transfer) revealing the effects of pattern transfer on roughness and uniformity. Finally, we calculate the cfactor function of various Next-Generation Lithography techniques and reveal their distinct footprint on the extent of cross-line correlations.

  4. The Edge

    NASA Technical Reports Server (NTRS)

    2006-01-01

    6 April 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the edge (running diagonally from the lower left to the upper right) of a trough, which is part of a large pit crater complex in Noachis Terra. This type of trough forms through the collapse of surface materials into the subsurface, and often begins as a series of individual pit craters. Over time, continued collapse increases the diameter of individual pits until finally, adjacent pits merge to form a trough such as the one captured in this image. The deep shadowed area is caused in part by an overhang; layered rock beneath this overhang is less resistant to erosion, and thus has retreated tens of meters backward, beneath the overhang. A person could walk up inside this 'cave' formed by the overhanging layered material.

    Location near: 47.0oS, 355.7oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  5. Armor Plate Surface Roughness Measurements

    DTIC Science & Technology

    2005-04-01

    Armor Plate Surface Roughness Measurements by Brian Stanton, William Coburn, and Thomas J. Pizzillo ARL-TR-3498 April 2005... Armor Plate Surface Roughness Measurements Brian Stanton, William Coburn and Thomas J. Pizzillo Sensors and Electron Devices Directorate...October 2004 5a. CONTRACT NUMBER 5b. GRANT NUMBER 4. TITLE AND SUBTITLE Armor Plate Surface Roughness Measurements 5c. PROGRAM ELEMENT NUMBER

  6. Evaporation of a nanodroplet on a rough substrate

    NASA Astrophysics Data System (ADS)

    Sun, Yong-Juan; Huang, Tao; Zhao, Jun-Feng; Chen, Yong

    2017-10-01

    The wettability and roughness of a substrate are crucial to the evolution of the contact angle and three-phase contact line in the evaporation of sessile droplets. In this paper, by performing molecular dynamics simulations for droplet evaporation at the nanoscale, we show that the wettability is more important than the roughness. For a smooth substrate, the evaporation behavior of a nanodroplet is similar to that at the macroscopic scale. This similarity is also observed in the case of a rough hydrophilic substrate. However, for a rough hydrophobic substrate, both the constant contact angle and contact line pinning appear in turn during evaporation. This suggests that the roughness of the hydrophobic substrate is useful for the evaporation technique in self-assembly at the nanoscale.

  7. Rough Sea Transfer Ship

    DTIC Science & Technology

    2008-07-01

    GROUP 2.3 2.36003 TRIAGE 20.00 60.00 GROUP 2.4 2.41005 VENDING MACHINE AREA 1.84 5.53 2.42001 LAUNDRY 27.15 81.44 GROUP 2.5...Research Enterprise Intern Program Rough Seas Transfer Ship Acknowledgements This report is the culmination of work conducted by students hired...under the National Research Enterprise Intern Program sponsored by the Office of Naval Research. This program provides an opportunity for students to

  8. Environmental Dataset Gateway (EDG) Search Widget

    EPA Pesticide Factsheets

    Use the Environmental Dataset Gateway (EDG) to find and access EPA's environmental resources. Many options are available for easily reusing EDG content in other other applications. This allows individuals to provide direct access to EPA's metadata outside the EDG interface. The EDG Search Widget makes it possible to search the EDG from another web page or application. The search widget can be included on your website by simply inserting one or two lines of code. Users can type a search term or lucene search query in the search field and retrieve a pop-up list of records that match that search.

  9. Determination of Joint Roughness Coefficients Using Roughness Parameters

    NASA Astrophysics Data System (ADS)

    Jang, Hyun-Sic; Kang, Seong-Seung; Jang, Bo-An

    2014-11-01

    This study used precisely digitized standard roughness profiles to determine roughness parameters such as statistical and 2D discontinuity roughness, and fractal dimensions. Our methods were based on the relationship between the joint roughness coefficient (JRC) values and roughness parameters calculated using power law equations. Statistical and 2D roughness parameters, and fractal dimensions correlated well with JRC values, and had correlation coefficients of over 0.96. However, all of these relationships have a 4th profile (JRC 6-8) that deviates by more than ±5 % from the JRC values given in the standard roughness profiles. This indicates that this profile is statistically different than the others. We suggest that fractal dimensions should be measured within the entire range of the divider, instead of merely measuring values within a suitable range. Normalized intercept values also correlated with the JRC values, similarly to the fractal dimension values discussed above. The root mean square first derivative values, roughness profile indexes, 2D roughness parameter, and fractal dimension values decreased as the sampling interval increased. However, the structure function values increased very rapidly with increasing sampling intervals. This indicates that the roughness parameters are not independent of the sampling interval, and that the different relationships between the JRC values and these roughness parameters are dependent on the sampling interval.

  10. RELATIONSHIP BETWEEN THE AERODYNAMIC ROUGHNESS LENGTH AND THE ROUGHNESS DENSITY IN CASES OF LOW ROUGHNESS DENSITY

    EPA Science Inventory

    This paper presents measurements of roughness length performed in a wind tunnel for low roughness density. The experiments were performed with both compact and porous obstacles (clusters), in order to simulate the behavior of sparsely vegetated surfaces.

  11. RELATIONSHIP BETWEEN THE AERODYNAMIC ROUGHNESS LENGTH AND THE ROUGHNESS DENSITY IN CASES OF LOW ROUGHNESS DENSITY

    EPA Science Inventory

    This paper presents measurements of roughness length performed in a wind tunnel for low roughness density. The experiments were performed with both compact and porous obstacles (clusters), in order to simulate the behavior of sparsely vegetated surfaces.

  12. Preliminary optical design of a varied line-space spectrograph for the multi-channel detection of near-edge X-ray absorption fine structure (NEXAFS) spectra in the 280-550 eV energy range

    SciTech Connect

    Wheeler, B.S.; McKinney, W.R.; Hussain, Z.; Padmore, H.

    1996-07-01

    The optical design of a varied line-space spectrograph for the multi-channel recording of NEXAFS spectra in a single {open_quotes}snapshot{close_quotes} is proposed. The spectrograph is to be used with a bending magnet source on beamline 7.3.2 at the Advanced Light Source (ALS). Approximately 20 volts of spectra are simultaneously imaged across a small square of material sample at each respective K absorption edge of carbon, nitrogen, and oxygen. Photoelectrons emitted from the material sample will be collected by an electron imaging microscope, the view field of which determines the sampling size. The sample also forms the exit slit of the optical system. This dispersive method of NEXAFS data acquisition is three to four orders of magnitude faster than the conventional method of taking data point-to-point using scanning of the grating. The proposed design is presented along with the design method and supporting SHADOW raytrace analysis.

  13. An edge index for topological insulators

    NASA Astrophysics Data System (ADS)

    Prodan, Emil

    2009-03-01

    Topological insulators display dissipationless currents flowing at the edges of the samples. These currents are associated to chiral edge modes, whose existence is intrinsically linked to the topology of the electronic states of the bulk. The edge modes can be easily investigated when the edges are smooth and have a periodicity, but as soon as the periodicity is absent, the problem becomes un-traceable by purely theoretical means. In my talk I will exemplify the use of non-commutative calculus to explore the properties, especially the stability of the edge modes. For example, using such techniques one can give a fairly elementary proof that the edge modes in Chern insulators survive even for a rough (random) edge. Similarly, for the Spin-Hall effect, one can define an observable and its associated current whose conductance remains quantized during various deformations of the Hamiltonian system. It turns out that in all cases, the edge conductance is given by the index of a Fredholm operator, which provides a new topological invariant linked directly to the edge rather than the bulk.

  14. Simulation study of the effect of molar mass dispersity on domain interfacial roughness in lamellae forming block copolymers for directed self-assembly

    NASA Astrophysics Data System (ADS)

    Peters, Andrew J.; Lawson, Richard A.; Nation, Benjamin D.; Ludovice, Peter J.; Henderson, Clifford L.

    2015-09-01

    A coarse-grained molecular dynamics model was used to study the thin film self-assembly and resulting pattern properties of block copolymer (BCP) systems with various molar mass dispersities. Diblock copolymers (i.e. A-b-B type) were simulated in an aligned lamellar state, which is one of the most common patterns of potential use for integrated circuit fabrication via directed self-assembly of BCPs. Effects of the molar mass dispersity (Ð) on feature pitch and interfacial roughness, which are critical lithographic parameters that have a direct impact on integrated circuit performance, were simulated. It was found that for a realistic distribution of polymer molecular weights, modeled by a Wesslau distribution, both line edge roughness (LER) and line width roughness (LWR) increase approximately linearly with increasing Ð, up to ˜45% of the monodisperse value at Ð = 1.5. Mechanisms of compensation for increased A-A and B-B roughness were considered. It was found that long and short chain positions were not correlated, and that long chains were significantly deformed in shape. The increase in LWR was due to the increase in LER and a constant correlation between the line edges. Unaligned systems show a correlation between domain width and local molecular weight, while systems aligned on an alternating pattern of A and B lines did not show any correlation. When the volume fraction of individual chains was allowed to vary, similar results were found when considering the Ð of the block as opposed to the Ð of the entire system.

  15. Lower limits of line resistance in nanocrystalline back end of line Cu interconnects

    NASA Astrophysics Data System (ADS)

    Hegde, Ganesh; Bowen, R. Chris; Rodder, Mark S.

    2016-11-01

    The strong non-linear increase in the Cu interconnect line resistance with decreasing linewidth presents a significant obstacle to their continued downscaling. In this letter we use the first principles density functional theory based electronic structure of Cu interconnects to find the lower limits of their line resistance for metal linewidths corresponding to future technology nodes. We find that even in the absence of scattering due to grain boundaries, edge roughness or interfaces, quantum confinement causes a severe increase in the line resistance of Cu. We also find that when the simplest scattering mechanism in the grain boundary scattering dominated limit is added to otherwise coherent electronic transmission in monocrystalline nanowires, the lower limit of line resistance is significantly higher than projected roadmap requirements in the International Technology Roadmap for Semiconductors.

  16. On the role of atomic metastability in the production of Balmer line radiation from ‘cold’ atomic hydrogen, deuterium and hydrogenic ion impurities in fusion edge plasmas

    NASA Astrophysics Data System (ADS)

    Hey, J. D.

    2012-03-01

    Published arguments, which assign an important role to atomic metastability in the production of ‘narrow’ Zeeman component radiation from the boundary region of fusion plasmas, are examined critically in relation to l-redistribution by proton and electron collisions, and mixing of unperturbed atomic states by the ion microfield and microfield gradient. It is concluded that these important processes indeed severely constrain the contribution from ‘metastable’ states to the generation of the hydrogen Balmer spectra, for electron concentrations above 1012 cm-3, as pointed out before by the present author (Hey et al 1999 J. Phys. B: At. Mol. Opt. Phys. 32 3555). The analysis of collision-induced l-redistribution represents an extension of that used previously (Hey et al 1996 Contrib. Plasma Phys. 36 583), applicable up to higher electron densities. For comparison purposes, we also consider the question of metastability of ionized helium in a low-temperature plasma, and that of some common hydrogenic impurities (C5+ and Ne9+) in a hydrogen (deuterium) fusion plasma. While for low nuclear charge Z the metastability of 2s1/2 levels is quenched by the plasma environment, it is much reduced in high-Z ions owing to the rapid increase with Z of the two-photon electric dipole (2E1) and magnetic dipole (M1) spontaneous transition rates to the ground state, whereas the role of the plasma in these cases is less important. The main new principle elaborated in this work is the sensitivity of atomic line strengths, and hence collision strengths, to perturbation by the plasma environment for transitions between fine-structure sublevels of the same principal quantum number. As the plasma microfield strength grows, ‘allowed’ transitions diminish in strength, while ‘forbidden’ transitions grow. However, owing to violation of the parity selection rule, there is an overall loss of collision strength available to transitions, resulting from the appearance of significant

  17. Engine roughness control means

    SciTech Connect

    Matsuura, M.; Doi, N.; Yoshioka, S.; Okimoto, H.; Veda, K.

    1987-08-04

    This patent describes a control system for a vehicle engine comprising engine condition detecting means for detecting an engine operating condition and producing an engine condition signal representing the engine operating condition, engine combustion control means for controlling a condition of combustion in the engine; and a control factor storage means for storing control factors for controlling the engine combustion. A modifying means connect the comparator means to receive the output signal and to modify the control factor from the storage means by the output of the comparator means so that the combustion control means is controlled by the modified control factor in a direction that the engine vibrations are suppressed. A reference signal changes means connected with the engine condition detecting means to change the reference roughness signal in accordance with the engine operating condition so that the reference signal is decreased when the engine is in idling operation.

  18. Subglacial roughness of the former Barents Sea ice sheet

    NASA Astrophysics Data System (ADS)

    Gudlaugsson, E.; Humbert, A.; Winsborrow, M.; Andreassen, K.

    2013-12-01

    The roughness of a glacier bed has high importance for the estimation of the sliding velocity and can also provide valuable insights into the dynamics and history of ice sheets, depending on scale. Measurement of basal properties in present-day ice sheets is restricted to ground-penetrating radar and seismics, with surveys retrieving relatively coarse data sets. Deglaciated areas, like the Barents Sea, can be surveyed by shipborne 2-D and 3-D seismics and multibeam sonar and provide the possibility of studying the basal roughness of former ice sheets and ice streams with high resolution. Here, for the first time, we quantify the subglacial roughness of the former Barents Sea ice sheet by estimating the spectral roughness of the basal topography. We also make deductions about the past flow directions by investigating how the roughness varies along a 2-D line as the orientation of the line changes. Lastly, we investigate how the estimated basal roughness is affected by the resolution of the basal topography data set by comparing the spectral roughness along a cross section using various sampling intervals. We find that the roughness typically varies on a similar scale as for other previously marine-inundated areas in West Antarctica, with subglacial troughs having very low roughness, consistent with fast ice flow and high rates of basal erosion. The resolution of the data set seems to be of minor importance when comparing roughness indices calculated with a fixed profile length. A strong dependence on track orientation is shown for all wavelengths, with profiles having higher roughness across former flow directions than along them.

  19. A second harmonic geomagnetic field line resonance at the inner edge of the plasma sheet - GEOS 1, ISEE 1, and ISEE 2 observations

    NASA Technical Reports Server (NTRS)

    Hughes, W. J.; Grard, R. J. L.

    1984-01-01

    A description is provided of observations made by GEOS 1, ISEE 1, and ISEE 2 of a hydromagnetic wave with a period approximately 90 s observed near 0200 LT between L = 9 and L = 6, close to the measured inner boundary of the plasma sheet. The wave magnetic oscillations perpendicular to and along the ambient field had similar amplitudes. Using primarily the transverse magnetic components, it is shown that the wave is a second harmonic resonance of the local geomagnetic field lines. ISEE 1 and 2 observed the opposite sense of polarization for about 30 min, although the spacecraft were separated by only 9 min in their orbit; this remarkable feature cannot be explained by either a stationary spatial boundary or a simple temporal boundary but could result from a rapid movement of the resonant region. It is argued that the most likely energy source is bounce resonance with medium energy (approximately 5 keV) ions. Calculations of the wave Poynting vector at ISEE 1 support this conclusion.

  20. Shear Stress Partitioning in Large Patches of Roughness in the Atmospheric Inertial Sublayer

    NASA Technical Reports Server (NTRS)

    Gillies, John A.; Nickling, William G.; King, James

    2007-01-01

    Drag partition measurements were made in the atmospheric inertial sublayer for six roughness configurations made up of solid elements in staggered arrays of different roughness densities. The roughness was in the form of a patch within a large open area and in the shape of an equilateral triangle with 60 m long sides. Measurements were obtained of the total shear stress (tau) acting on the surfaces, the surface shear stress on the ground between the elements (tau(sub S)) and the drag force on the elements for each roughness array. The measurements indicated that tau(sub S) quickly reduced near the leading edge of the roughness compared with tau, and a tau(sub S) minimum occurs at a normalized distance (x/h, where h is element height) of approx. -42 (downwind of the roughness leading edge is negative), then recovers to a relatively stable value. The location of the minimum appears to scale with element height and not roughness density. The force on the elements decreases exponentially with normalized downwind distance and this rate of change scales with the roughness density, with the rate of change increasing as roughness density increases. Average tau(sub S): tau values for the six roughness surfaces scale predictably as a function of roughness density and in accordance with a shear stress partitioning model. The shear stress partitioning model performed very well in predicting the amount of surface shear stress, given knowledge of the stated input parameters for these patches of roughness. As the shear stress partitioning relationship within the roughness appears to come into equilibrium faster for smaller roughness element sizes it would also appear the shear stress partitioning model can be applied with confidence for smaller patches of smaller roughness elements than those used in this experiment.

  1. Shear Stress Partitioning in Large Patches of Roughness in the Atmospheric Inertial Sublayer

    NASA Technical Reports Server (NTRS)

    Gillies, John A.; Nickling, William G.; King, James

    2007-01-01

    Drag partition measurements were made in the atmospheric inertial sublayer for six roughness configurations made up of solid elements in staggered arrays of different roughness densities. The roughness was in the form of a patch within a large open area and in the shape of an equilateral triangle with 60 m long sides. Measurements were obtained of the total shear stress (tau) acting on the surfaces, the surface shear stress on the ground between the elements (tau(sub S)) and the drag force on the elements for each roughness array. The measurements indicated that tau(sub S) quickly reduced near the leading edge of the roughness compared with tau, and a tau(sub S) minimum occurs at a normalized distance (x/h, where h is element height) of approx. -42 (downwind of the roughness leading edge is negative), then recovers to a relatively stable value. The location of the minimum appears to scale with element height and not roughness density. The force on the elements decreases exponentially with normalized downwind distance and this rate of change scales with the roughness density, with the rate of change increasing as roughness density increases. Average tau(sub S): tau values for the six roughness surfaces scale predictably as a function of roughness density and in accordance with a shear stress partitioning model. The shear stress partitioning model performed very well in predicting the amount of surface shear stress, given knowledge of the stated input parameters for these patches of roughness. As the shear stress partitioning relationship within the roughness appears to come into equilibrium faster for smaller roughness element sizes it would also appear the shear stress partitioning model can be applied with confidence for smaller patches of smaller roughness elements than those used in this experiment.

  2. Roughness Effects on Fretting Fatigue

    NASA Astrophysics Data System (ADS)

    Yue, Tongyan; Abdel Wahab, Magd

    2017-05-01

    Fretting is a small oscillatory relative motion between two normal loaded contact surfaces. It may cause fretting fatigue, fretting wear and/or fretting corrosion damage depending on various fretting couples and working conditions. Fretting fatigue usually occurs at partial slip condition, and results in catastrophic failure at the stress levels below the fatigue limit of the material. Many parameters may affect fretting behaviour, including the applied normal load and displacement, material properties, roughness of the contact surfaces, frequency, etc. Since fretting damage is undesirable due to contacting, the effect of rough contact surfaces on fretting damage has been studied by many researchers. Experimental method on this topic is usually focusing on rough surface effects by finishing treatment and random rough surface effects in order to increase fretting fatigue life. However, most of numerical models on roughness are based on random surface. This paper reviewed both experimental and numerical methodology on the rough surface effects on fretting fatigue.

  3. Roughness characteristics of natural channels

    USGS Publications Warehouse

    Barnes, Harry Hawthorne

    1967-01-01

    Color photographs and descriptive data are presented for 50 stream channels for which roughness coefficients have been determined. All hydraulic computations involving flow in open channels require an evaluation of the roughness characteristics of the channel. In the absence of a satisfactory quantitative procedure this evaluation remains chiefly an art. The ability to evaluate roughness coefficients must be developed through experience. One means of gaining this experience is by examining and becoming acquainted with the appearance of some typical channels whose roughness coefficients are known. The photographs and data contained in this report represent a wide range of channel conditions. Familiarity with the appearance, geometry, and roughness characteristics of these channels will improve the engineer's ability to select roughness coefficients for other channels .

  4. Laser Roughing of PCD

    NASA Astrophysics Data System (ADS)

    Brecher, Christian; Emonts, Michael; Hermani, Jan-Patrick; Storms, Thomas

    Polycrystalline diamond (PCD) has become an indispensable tool material for efficient machining of various materials. In manufacturing of PCD tools the finishing process in order to obtain the required surface and edge quality is mostly done by grinding. Due to the high hardness and wear resistance of PCD grinding is characterized by low material removal rates and high wear of the grinding wheel. The Fraunhofer IPT has developed a novel finishing method for PCD cutting tools, which combines laser processing and grinding. Short pulse laser ablation is used to completely remove a PCD surface layer of about 180 μm. To achieve the required tool quality the remaining 20 μm are removed by subsequent grinding. The obtained results demonstrate that the combination allows reducing the finishing time by more than 50%. Therefore, laser technology has a high potential to make the finishing process more efficient and significantly lower manufacturing costs.

  5. Roughness Measurement of Dental Materials

    NASA Astrophysics Data System (ADS)

    Shulev, Assen; Roussev, Ilia; Karpuzov, Simeon; Stoilov, Georgi; Ignatova, Detelina; See, Constantin von; Mitov, Gergo

    2016-06-01

    This paper presents a roughness measurement of zirconia ceramics, widely used for dental applications. Surface roughness variations caused by the most commonly used dental instruments for intraoral grinding and polishing are estimated. The applied technique is simple and utilizes the speckle properties of the scattered laser light. It could be easily implemented even in dental clinic environment. The main criteria for roughness estimation is the average speckle size, which varies with the roughness of zirconia. The algorithm used for the speckle size estimation is based on the normalized autocorrelation approach.

  6. Edge location to subpixel values in digital imagery.

    PubMed

    Tabatabai, A J; Mitchell, O R

    1984-02-01

    A new method for locating edges in digital data to subpixel values and which is invariant to additive and multiplicative changes in the data is presented. For one-dimensional edge patterns an ideal edge is fit to the data by matching moments. It is shown that the edge location is related to the so-called ``Christoffel numbers.'' Also presented is the study of the effect of additive noise on edge location. The method is extended to include two-dimensional edge patterns where a line equation is derived to locate an edge. This in turn is compared with the standard Hueckel edge operator. An application of the new edge operator as an edge detector is also provided and is compared with Sobel and Hueckel edge detectors in presence and absence of noise.

  7. Surface roughness measurements

    NASA Astrophysics Data System (ADS)

    Howard, Thomas G.

    1994-10-01

    The Optics Division is currently in the research phase of producing grazing-incidence mirrors to be used in x-ray detector applications. The traditional method of construction involves labor-intensive glass grinding. This also culminates in a relatively heavy mirror. For lower resolution applications, the mirrors may be of a replicated design which involves milling a mandrel as a negative of the final shape and electroplating the cylindrical mirror onto it. The mirror is then separated from the mandrel by cooling. The mandrel will shrink more than the 'shell' (mirror) allowing it to be pulled from the mandrel. Ulmer (2) describes this technique and its variations in more detail. To date, several mirrors have been tested at MSFC by the Optical Fabrication Branch by focusing x-ray energy onto a detector with limited success. Little is known about the surface roughness of the actual mirror. Hence, the attempt to gather data on these surfaces. The test involves profiling the surface of a sample, replicating the surface as described above, and then profiling the replicated surface.

  8. Roughness and waviness requirements for laminar flow surfaces

    NASA Technical Reports Server (NTRS)

    Obara, Clifford J.; Holmes, Bruce J.

    1986-01-01

    Many modern metal and composite airframe manufacturing techniques can provide surface smoothness which is compatible with natural laminar flow (NLF) requirements. An important consideration is manufacturing roughness of the surface in the form of steps and gaps perpendicular to the freestream. The principal challenge to the design and manufacture of laminar flow surfaces today appears to be in the installation of leading-edge panels on wing, nacelle, and empennage surfaces. A similar challenge is in the installation of access panels, doors, windows, fuselage noses, and engine nacelles. Past work on roughness and waviness manufacturing tolerances and comparisons with more recent experiments are reviewed.

  9. Edge detection and localization with edge pattern analysis and inflection characterization

    NASA Astrophysics Data System (ADS)

    Jiang, Bo

    2012-05-01

    In general edges are considered to be abrupt changes or discontinuities in two dimensional image signal intensity distributions. The accuracy of front-end edge detection methods in image processing impacts the eventual success of higher level pattern analysis downstream. To generalize edge detectors designed from a simple ideal step function model to real distortions in natural images, research on one dimensional edge pattern analysis to improve the accuracy of edge detection and localization proposes an edge detection algorithm, which is composed by three basic edge patterns, such as ramp, impulse, and step. After mathematical analysis, general rules for edge representation based upon the classification of edge types into three categories-ramp, impulse, and step (RIS) are developed to reduce detection and localization errors, especially reducing "double edge" effect that is one important drawback to the derivative method. But, when applying one dimensional edge pattern in two dimensional image processing, a new issue is naturally raised that the edge detector should correct marking inflections or junctions of edges. Research on human visual perception of objects and information theory pointed out that a pattern lexicon of "inflection micro-patterns" has larger information than a straight line. Also, research on scene perception gave an idea that contours have larger information are more important factor to determine the success of scene categorization. Therefore, inflections or junctions are extremely useful features, whose accurate description and reconstruction are significant in solving correspondence problems in computer vision. Therefore, aside from adoption of edge pattern analysis, inflection or junction characterization is also utilized to extend traditional derivative edge detection algorithm. Experiments were conducted to test my propositions about edge detection and localization accuracy improvements. The results support the idea that these edge

  10. Wetting failure of hydrophilic surfaces promoted by surface roughness

    PubMed Central

    Zhao, Meng-Hua; Chen, Xiao-Peng; Wang, Qing

    2014-01-01

    Wetting failure is of vital importance to many physical phenomena, such as industrial coating and drop emission. Here we show when and how the surface roughness promotes the destabilization of a moving contact line on a hydrophilic surface. Beyond the balance of the driving force and viscous resistance where a stable wetting interface is sustained, wetting failure occurs and is modified by the roughness of the surface. The promoting effect arises only when the wetting velocity is high enough to create a gas-liquid-solid composite interface in the vicinity of the moving contact line, and it is a function of the intrinsic contact angle and proportion of solid tops. We propose a model to explain splashes of rough solid spheres impacting into liquids. It reveals a novel concept that dynamic wetting on hydrophilic rough surfaces can be similar to that on hydrophobic surfaces, and brings a new way to design surfaces with specific wetting properties. PMID:24948390

  11. Effects of surface roughness and vortex generators on the LS(1)-0417MOD airfoil

    SciTech Connect

    Reuss, R.L.; Hoffman, M.J.; Gregorek, G.M.

    1995-12-01

    An 18-inch constant-chord model of the LS(l)-0417MOD airfoil section was tested under two dimensional steady state conditions ate University 7{times}10 Subsonic Wind Tunnel. The objective was to document section lift and moment characteristics model and air flow conditions. Surface pressure data was acquired at {minus}60{degrees} through + 230{degrees} geometric angles of attack, at a nominal 1 million Reynolds number. Cases with and without leading edge grit roughness were investigated. The leading edge mulated blade conditions in the field. Additionally, surface pressure data were acquired for Reynolds numbers of 1.5 and 2.0 million, with and without leading edge grit roughness; the angle of attack was limited to a {minus}20{degrees} to 40{degrees} range. In general, results showed lift curve slope sensitivities to Reynolds number and roughness. The maximum lift coefficient was reduced as much as 29% by leading edge roughness. Moment coefficient showed little sensitivity to roughness beyond 50{degrees} angle of attack, but the expected decambering effect of a thicker boundary layer with roughness did show at lower angles. Tests were also conducted with vortex generators located at the 30% chord location on the upper surface only, at 1 and 1.5 million Reynolds numbers, with and without leading edge grit roughness. In general, with leading edge grit roughness applied, the vortex generators restored 85 percent of the baseline level of maximum lift coefficient but with a more sudden stall break and at a higher angle of attack than the baseline.

  12. Wind tunnel model surface gauge for measuring roughness

    NASA Technical Reports Server (NTRS)

    Vorburger, T. V.; Gilsinn, D. E.; Teague, E. C.; Giauque, C. H. W.; Scire, F. E.; Cao, L. X.

    1987-01-01

    The optical inspection of surface roughness research has proceeded along two different lines. First, research into a quantitative understanding of light scattering from metal surfaces and into the appropriate models to describe the surfaces themselves. Second, the development of a practical instrument for the measurement of rms roughness of high performance wind tunnel models with smooth finishes. The research is summarized, with emphasis on the second avenue of research.

  13. Generalizing roughness: experiments with flow-oriented roughness

    NASA Astrophysics Data System (ADS)

    Trevisani, Sebastiano

    2015-04-01

    Surface texture analysis applied to High Resolution Digital Terrain Models (HRDTMs) improves the capability to characterize fine-scale morphology and permits the derivation of useful morphometric indexes. An important indicator to be taken into account in surface texture analysis is surface roughness, which can have a discriminant role in the detection of different geomorphic processes and factors. The evaluation of surface roughness is generally performed considering it as an isotropic surface parameter (e.g., Cavalli, 2008; Grohmann, 2011). However, surface texture has often an anisotropic character, which means that surface roughness could change according to the considered direction. In some applications, for example involving surface flow processes, the anisotropy of roughness should be taken into account (e.g., Trevisani, 2012; Smith, 2014). Accordingly, we test the application of a flow-oriented directional measure of roughness, computed considering surface gravity-driven flow. For the calculation of flow-oriented roughness we use both classical variogram-based roughness (e.g., Herzfeld,1996; Atkinson, 2000) as well as an ad-hoc developed robust modification of variogram (i.e. MAD, Trevisani, 2014). The presented approach, based on a D8 algorithm, shows the potential impact of considering directionality in the calculation of roughness indexes. The use of flow-oriented roughness could improve the definition of effective proxies of impedance to flow. Preliminary results on the integration of directional roughness operators with morphometric-based models, are promising and can be extended to more complex approaches. Atkinson, P.M., Lewis, P., 2000. Geostatistical classification for remote sensing: an introduction. Computers & Geosciences 26, 361-371. Cavalli, M. & Marchi, L. 2008, "Characterization of the surface morphology of an alpine alluvial fan using airborne LiDAR", Natural Hazards and Earth System Science, vol. 8, no. 2, pp. 323-333. Grohmann, C

  14. Gliding swifts attain laminar flow over rough wings.

    PubMed

    Lentink, David; de Kat, Roeland

    2014-01-01

    Swifts are among the most aerodynamically refined gliding birds. However, the overlapping vanes and protruding shafts of their primary feathers make swift wings remarkably rough for their size. Wing roughness height is 1-2% of chord length on the upper surface--10,000 times rougher than sailplane wings. Sailplanes depend on extreme wing smoothness to increase the area of laminar flow on the wing surface and minimize drag for extended glides. To understand why the swift does not rely on smooth wings, we used a stethoscope to map laminar flow over preserved wings in a low-turbulence wind tunnel. By combining laminar area, lift, and drag measurements, we show that average area of laminar flow on swift wings is 69% (n = 3; std 13%) of their total area during glides that maximize flight distance and duration--similar to high-performance sailplanes. Our aerodynamic analysis indicates that swifts attain laminar flow over their rough wings because their wing size is comparable to the distance the air travels (after a roughness-induced perturbation) before it transitions from laminar to turbulent. To interpret the function of swift wing roughness, we simulated its effect on smooth model wings using physical models. This manipulation shows that laminar flow is reduced and drag increased at high speeds. At the speeds at which swifts cruise, however, swift-like roughness prolongs laminar flow and reduces drag. This feature gives small birds with rudimentary wings an edge during the evolution of glide performance.

  15. Gliding Swifts Attain Laminar Flow over Rough Wings

    PubMed Central

    Lentink, David; de Kat, Roeland

    2014-01-01

    Swifts are among the most aerodynamically refined gliding birds. However, the overlapping vanes and protruding shafts of their primary feathers make swift wings remarkably rough for their size. Wing roughness height is 1–2% of chord length on the upper surface—10,000 times rougher than sailplane wings. Sailplanes depend on extreme wing smoothness to increase the area of laminar flow on the wing surface and minimize drag for extended glides. To understand why the swift does not rely on smooth wings, we used a stethoscope to map laminar flow over preserved wings in a low-turbulence wind tunnel. By combining laminar area, lift, and drag measurements, we show that average area of laminar flow on swift wings is 69% (n = 3; std 13%) of their total area during glides that maximize flight distance and duration—similar to high-performance sailplanes. Our aerodynamic analysis indicates that swifts attain laminar flow over their rough wings because their wing size is comparable to the distance the air travels (after a roughness-induced perturbation) before it transitions from laminar to turbulent. To interpret the function of swift wing roughness, we simulated its effect on smooth model wings using physical models. This manipulation shows that laminar flow is reduced and drag increased at high speeds. At the speeds at which swifts cruise, however, swift-like roughness prolongs laminar flow and reduces drag. This feature gives small birds with rudimentary wings an edge during the evolution of glide performance. PMID:24964089

  16. Advanced CD-SEM metrology for qualification of DSA patterns using coordinated line epitaxy (COOL) process

    NASA Astrophysics Data System (ADS)

    Kato, Takeshi; Konishi, Junko; Ikota, Masami; Yamaguchi, Satoru; Seino, Yuriko; Sato, Hironobu; Kasahara, Yusuke; Azuma, Tsukasa

    2016-03-01

    Directed self-assembly (DSA) applying chemical epitaxy is one of the promising lithographic solutions for next generation semiconductor device manufacturing. Especially, DSA lithography using coordinated line epitaxy (COOL) process is obviously one of candidates which could be the first generation of DSA applying PS-b-PMMA block copolymer (BCP) for sub-15nm dense line patterning . DSA can enhance the pitch resolutions, and can mitigate CD errors to the values much smaller than those of the originally exposed guiding patterns. On the other hand, local line placement error often results in a worse value, with distinctive trends depending on the process conditions. To address this issue, we introduce an enhanced measurement technology of DSA line patterns with distinguishing their locations in order to evaluate nature of edge placement and roughness corresponding to individual pattern locations by using images of CD-SEM. Additionally correlations among edge roughness of each line and each space are evaluated and discussed. This method can visualize features of complicated roughness easily to control COOL process. As a result, we found the followings. (1) Line placement error and line placement roughness of DSA were slightly different each other depending on their relative position to the chemical guide patterns. (2) In middle frequency area of PSD (Power Spectral Density) analysis graphs, it was observed that shapes were sensitively changed by process conditions of chemical stripe guide size and anneals temperature. (3) Correlation coefficient analysis using PSD was able to clarify characteristics of latent defect corresponding to physical and chemical property of BCP materials.

  17. Sorption selectivity of birnessite particle edges: a d-PDF analysis of Cd(ii) and Pb(ii) sorption by δ-MnO2 and ferrihydrite.

    PubMed

    van Genuchten, Case M; Peña, Jasquelin

    2016-08-10

    Birnessite minerals (layer-type MnO2), which bear both internal (cation vacancies) and external (particle edges) metal sorption sites, are important sinks of contaminants in soils and sediments. Although the particle edges of birnessite minerals often dominate the total reactive surface area, especially in the case of nanoscale crystallites, the metal sorption reactivity of birnessite particle edges remains elusive. In this study, we investigated the sorption selectivity of birnessite particle edges by combining Cd(ii) and Pb(ii) adsorption isotherms at pH 5.5 with surface structural characterization by differential pair distribution function (d-PDF) analysis. We compared the sorption reactivity of δ-MnO2 to that of the nanomineral, 2-line ferrihydrite, which exhibits only external surface sites. Our results show that, whereas Cd(ii) and Pb(ii) both bind to birnessite layer vacancies, only Pb(ii) binds extensively to birnessite particle edges. For ferrihydrite, significant Pb(ii) adsorption to external sites was observed (roughly 20 mol%), whereas Cd(ii) sorption was negligible. These results are supported by bond valence calculations that show comparable degrees of saturation of oxygen atoms on birnessite and ferrihydrite particle edges. Therefore, we propose that the sorption selectivity of birnessite edges follows the same order of that reported previously for ferrihydrite: Ca(ii) < Cd(ii) < Ni(ii) < Zn(ii) < Cu(ii) < Pb(ii).

  18. Ordered roughness effects on NACA 0026 airfoil

    NASA Astrophysics Data System (ADS)

    Harun, Z.; Abbas, A. A.; Dheyaa, R. Mohammed; Ghazali, M. I.

    2016-10-01

    The effects of highly-ordered rough surface - riblets, applied onto the surface of a NACA 0026 airfoil, are investigated experimentally using wind tunnel. The riblets are arranged in directionally converging - diverging pattern with dimensions of height, h = 1 mm, pitch or spacing, s = 1 mm, yaw angle α = 0o and 10o The airfoil with external geometry of 500 mm span, 600 mm chord and 156 mm thickness has been built using mostly woods and aluminium. Turbulence quantities are collected using hotwire anemometry. Hotwire measurements show that flows past converging and diverging pattern inherit similar patterns in the near-wall region for both mean velocity and turbulence intensities profiles. The mean velocity profiles in logarithmic regions for both flows past converging and diverging riblet pattern are lower than that with yaw angle α = 0o. Converging riblets cause the boundary layer to thicken and the flow with yaw angle α = 0o produces the thinnest boundary layer. Both the converging and diverging riblets cause pronounced outer peaks in the turbulence intensities profiles. Most importantly, flows past converging and diverging pattern experience 30% skin friction reductions. Higher order statistics show that riblet surfaces produce similar effects due to adverse pressure gradient. It is concluded that a small strip of different ordered roughness features applied at a leading edge of an airfoil can change the turbulence characteristics dramatically.

  19. Parametric Flow Visualization of Dynamic Roughness Effects

    NASA Astrophysics Data System (ADS)

    Jakkali, Vinay

    The ever growing need in the aircraft industry to enhance the performance of a flight vehicle has led to active areas of research which focus on the control of the local boundary layer by both passive and active methods. An effective flow control mechanism can improve the performance of a flight vehicle in various ways, one of which is eliminating boundary layer separation. To be effective the mechanism not only needs to control the boundary layer as desired, but also use less energy than the resulting energy savings. In this study, the effectiveness of an active flow control technique known as dynamic roughness (DR) has been explored to eliminate the laminar separation bubble near the leading edge and also to eliminate the stall on a NACA 0012 airfoil wing. As opposed to static roughness, dynamic roughness utilizes small time-dependent deforming elements or humps with displacement amplitudes that are on the order of the local boundary layer height to energize the local boundary layer. DR is primarily characterized by the maximum amplitude and operating frequency. A flow visualization study was conducted on a 2D NACA 0012 airfoil model at different angles of attack, and also varying the Reynolds number and DR actuation frequency with fixed maximum DR amplitude. The experimental results from this study suggests that DR is an effective method of reattaching a totally separated boundary layer. In addition, this study discusses some of the fundamental physics behind the working of DR and proposes some non-dimensional terms that may help to explain the driving force behind the mechanism.

  20. The Aerodynamic Characteristics of Airfoils as Affected by Surface Roughness

    NASA Technical Reports Server (NTRS)

    HOCKER RAY W

    1933-01-01

    The effect on airfoil characteristics of surface roughness of varying degrees and types at different locations on an airfoil was investigated at high values of the Reynolds number in a variable density wind tunnel. Tests were made on a number of National Advisory Committee for Aeronautics (NACA) 0012 airfoil models on which the nature of the surface was varied from a rough to a very smooth finish. The effect on the airfoil characteristics of varying the location of a rough area in the region of the leading edge was also investigated. Airfoils with surfaces simulating lap joints were also tested. Measurable adverse effects were found to be caused by small irregularities in airfoil surfaces which might ordinarily be overlooked. The flow is sensitive to small irregularities of approximately 0.0002c in depth near the leading edge. The tests made on the surfaces simulating lap joints indicated that such surfaces cause small adverse effects. Additional data from earlier tests of another symmetrical airfoil are also included to indicate the variation of the maximum lift coefficient with the Reynolds number for an airfoil with a polished surface and with a very rough one.

  1. Randomized SUSAN edge detector

    NASA Astrophysics Data System (ADS)

    Qu, Zhi-Guo; Wang, Ping; Gao, Ying-Hui; Wang, Peng

    2011-11-01

    A speed up technique for the SUSAN edge detector based on random sampling is proposed. Instead of sliding the mask pixel by pixel on an image as the SUSAN edge detector does, the proposed scheme places the mask randomly on pixels to find edges in the image; we hereby name it randomized SUSAN edge detector (R-SUSAN). Specifically, the R-SUSAN edge detector adopts three approaches in the framework of random sampling to accelerate a SUSAN edge detector: procedure integration of response computation and nonmaxima suppression, reduction of unnecessary processing for obvious nonedge pixels, and early termination. Experimental results demonstrate the effectiveness of the proposed method.

  2. High sensitive THz superconducting hot electron bolometer mixers and transition edge sensors

    NASA Astrophysics Data System (ADS)

    Zhang, W.; Miao, W.; Zhou, K. M.; Guo, X. H.; Zhong, J. Q.; Shi, S. C.

    2016-11-01

    Terahertz band, which is roughly defined as 0.1 THz to 10 THz, is an interesting frequency region of the electromagnetic spectrum to be fully explored in astronomy. THz observations play key roles in astrophysics and cosmology. High sensitive heterodyne and direct detectors are the main tools for the detection of molecular spectral lines and fine atomic structure spectral lines, which are very important tracers for probing the physical and chemical properties and dynamic processes of objects such as star and planetary systems. China is planning to build an THz telescope at Dome A, Antarctica, a unique site for ground-based THz observations. We are developing THz superconducting hot electron bolometer (HEB) mixers and transition edge sensors (TES), which are quantum limited and back-ground limited detectors, respectively. Here we first introduce the working principles of superconducting HEB and TES, and then mainly present the results achieved at Purple mountain Observatory.

  3. Transition in a Supersonic Boundary-Layer Due to Roughness and Acoustic Disturbances

    NASA Technical Reports Server (NTRS)

    Balakumar, P.

    2003-01-01

    The transition process induced by the interaction of an isolated roughness with acoustic disturbances in the free stream is numerically investigated for a boundary layer over a flat plate with a blunted leading edge at a free stream Mach number of 3.5. The roughness is assumed to be of Gaussian shape and the acoustic disturbances are introduced as boundary condition at the outer field. The governing equations are solved using the 5'h-rder accurate weighted essentially non-oscillatory (WENO) scheme for space discretization and using third- order total-variation-diminishing (TVD) Runge- Kutta scheme for time integration. The steady field induced by the two and three-dimensional roughness is also computed. The flow field induced by two-dimensional roughness exhibits different characteristics depending on the roughness heights. At small roughness heights the flow passes smoothly over the roughness, at moderate heights the flow separates downstream of the roughness and at larger roughness heights the flow separates upstream and downstream of the roughness. Computations also show that disturbances inside the boundary layer is due to the direct interaction of the acoustic waves and isolated roughness plays a minor role in generating instability waves.

  4. Does surface roughness amplify wetting?

    SciTech Connect

    Malijevský, Alexandr

    2014-11-14

    Any solid surface is intrinsically rough on the microscopic scale. In this paper, we study the effect of this roughness on the wetting properties of hydrophilic substrates. Macroscopic arguments, such as those leading to the well-known Wenzel's law, predict that surface roughness should amplify the wetting properties of such adsorbents. We use a fundamental measure density functional theory to demonstrate the opposite effect from roughness for microscopically corrugated surfaces, i.e., wetting is hindered. Based on three independent analyses we show that microscopic surface corrugation increases the wetting temperature or even makes the surface hydrophobic. Since for macroscopically corrugated surfaces the solid texture does indeed amplify wetting there must exist a crossover between two length-scale regimes that are distinguished by opposite response on surface roughening. This demonstrates how deceptive can be efforts to extend the thermodynamical laws beyond their macroscopic territory.

  5. Measuring Roughnesses Of Optical Surfaces

    NASA Technical Reports Server (NTRS)

    Coulter, Daniel R.; Al-Jumaily, Gahnim A.; Raouf, Nasrat A.; Anderson, Mark S.

    1994-01-01

    Report discusses use of scanning tunneling microscopy and atomic force microscopy to measure roughnesses of optical surfaces. These techniques offer greater spatial resolution than other techniques. Report notes scanning tunneling microscopes and atomic force microscopes resolve down to 1 nm.

  6. Mechanism for low-etching resistance and surface roughness of ArF photoresist during plasma irradiation

    SciTech Connect

    Jinnai, Butsurin; Koyama, Koji; Kato, Keisuke; Yasuda, Atsushi; Momose, Hikaru; Samukawa, Seiji

    2009-03-01

    ArF excimer laser lithography was introduced to fabricate nanometer-scale devices and uses chemically amplified photoresist polymers including photoacid generators (PAGs). Because plasma-etching processes cause serious problems related to the use of ArF photoresists, such as line-edge roughness and low etching selectivity, we have to understand the interaction between plasma and ArF photoresist polymers. Investigating the effects of surface temperature and the irradiation species from plasma, we have found that ion irradiation by itself did not drastically increase the roughness or etching rate of ArF photoresist films unless it was combined with ultraviolet/vacuum ultraviolet (UV/VUV) photon irradiation. The structures of ArF photoresist polymers were largely unchanged by ion irradiation alone but were destroyed by combinations of ion and UV/VUV-photon irradiation. Our results suggested that PAG-mediated deprotection induced by UV/VUV-photon irradiation was amplified at surface temperatures above 100 deg. C. The etching rate and surface roughness of plasma-etched ArF photoresists are affected by the irradiation species and surface temperature during plasma etching. UV/VUV-photon irradiation plays a particularly important role in the interaction between plasma and ArF photoresist polymers.

  7. Radar-aeolian roughness project

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald; Dobrovolskis, A.; Gaddis, L.; Iversen, J. D.; Lancaster, N.; Leach, Rodman N.; Rasnussen, K.; Saunders, S.; Vanzyl, J.; Wall, S.

    1991-01-01

    The objective is to establish an empirical relationship between measurements of radar, aeolian, and surface roughness on a variety of natural surfaces and to understand the underlying physical causes. This relationship will form the basis for developing a predictive equation to derive aeolian roughness from radar backscatter. Results are given from investigations carried out in 1989 on the principal elements of the project, with separate sections on field studies, radar data analysis, laboratory simulations, and development of theory for planetary applications.

  8. Optical Receivers With Rough Reflectors

    NASA Technical Reports Server (NTRS)

    Vilnrotter, Victor A.

    1989-01-01

    Receiver for optical communications uses rough reflector instead of diffraction-limited reflector customarily thought necessary for such systems. Rough reflector collects and focuses optical signal. Other receiver components include narrow-passband optical filter to reject out-of-band background radiation, spatial filter to limit receiver field of view, optical-detector array (typically two concentric detectors), and postdetection processor to reconstruct transmitted message.

  9. A Controlled Trial to Determine the Efficacy of Red and Near-Infrared Light Treatment in Patient Satisfaction, Reduction of Fine Lines, Wrinkles, Skin Roughness, and Intradermal Collagen Density Increase

    PubMed Central

    Matuschka, Karsten

    2014-01-01

    Abstract Objective: The purpose of this study was to investigate the safety and efficacy of two novel light sources for large area and full body application, providing polychromatic, non-thermal photobiomodulation (PBM) for improving skin feeling and appearance. Background data: For non-thermal photorejuvenation, laser and LED light sources have been demonstrated to be safe and effective. However, lasers and LEDs may offer some disadvantages because of dot-shaped (punctiform) emission characteristics and their narrow spectral bandwidths. Because the action spectra for tissue regeneration and repair consist of more than one wavelength, we investigated if it is favorable to apply a polychromatic spectrum covering a broader spectral region for skin rejuvenation and repair. Materials and methods: A total of 136 volunteers participated in this prospective, randomized, and controlled study. Of these volunteers, 113 subjects randomly assigned into four treatment groups were treated twice a week with either 611–650 or 570–850 nm polychromatic light (normalized to ∼9 J/cm2 in the range of 611–650 nm) and were compared with controls (n=23). Irradiances and treatment durations varied in all treatment groups. The data collected at baseline and after 30 sessions included blinded evaluations of clinical photography, ultrasonographic collagen density measurements, computerized digital profilometry, and an assessment of patient satisfaction. Results: The treated subjects experienced significantly improved skin complexion and skin feeling, profilometrically assessed skin roughness, and ultrasonographically measured collagen density. The blinded clinical evaluation of photographs confirmed significant improvement in the intervention groups compared with the control. Conclusions: Broadband polychromatic PBM showed no advantage over the red-light-only spectrum. However, both novel light sources that have not been previously used for PBM have demonstrated efficacy and

  10. Effect of two-scale roughness on boundary layer transition over a heated flat plate: Part 1 -- Surface heat transfer

    SciTech Connect

    Pinson, M.W.; Wang, T.

    2000-04-01

    An experimental study was conducted to investigate surface heat transfer and boundary layer development associated with flow over a flat test surface covered with two roughness scales. Two-scale roughness was used because in-service aeroengines commonly display larger roughness concentrated at the leading edge with smaller roughness distributed downstream. The first scale, covering up to the first 5 cm of the test surface, was in the form of a sandpaper strip, an aluminum strip, or a cylinder. The second roughness scale covered the remainder of the test surface (2 m) in the form of sandpaper or a smooth surface. In Part 1, the surface heat transfer results are examined. Even though the roughness scales were hydraulically smooth, they induced significantly earlier transition onset, with the two-dimensional roughness causing earlier transition than three-dimensional roughness. All of the rough/smooth cases unexpectedly triggered earlier transition than rough/rough cases. This indicated that the scale of the step-change at the joint between two roughness scales was predominant over the downstream roughness on inducing early transition. Reducing the overall height of the step change was shown to have a greater effect on transition than the specific geometry of the roughness scale.

  11. Modeling of the ``death-ray'' phenomenon in tokamak edge

    NASA Astrophysics Data System (ADS)

    Umansky, M. V.; Brunner, D.; Labombard, B.; Rognlien, T. D.

    2012-03-01

    In the ``death-ray'' regime often seen in tokamak edge plasma experiments, the downstream electron pressure, as measured by Langmuir probes at the divertor plate, exceeds the upstream values by nearly a factor of 2 over a narrow radial region at the strike point [1,2]. However, recent studies on Alcator C-Mod indicate that the death-ray over-pressure may be a result of local plasma perturbation by the negative probe bias [3]. We investigate the effects of probe perturbation of the plasma using the tokamak edge fluid code UEDGE. The code models a slab-like configuration roughly matching the basic dimensions and characteristics of edge plasma in Alcator C-Mod near detachment, where the death-ray is often observed. In the code setup, a small axisymmetric segment of target plate is biased, which mimics a plate-mounted Langmuir probe. It is observed in the simulations that at sufficiently large negative bias voltage the probe substantially modifies the local plasma characteristics. Moreover, the simulations reproduce the overpressure along the field line, similar to the experimental death-ray; pointing to the interplay of ion-neutral momentum exchange and the sheath boundary conditions [4].[4pt] [1] D. Brunner et al., APS DPP 2010, poster TP9.00069;[0pt] [2] B. LaBombard et al., J. Nucl. Mater. 241-243, 149-166 (1997);[0pt] [3] A. Loarte et al., Nucl. Fusion 38, 331 (1998);[0pt] [4] M.V. Umansky et al., Contrib. Plasma Phys., accepted (2011).

  12. Nanoindentation near the edge

    Treesearch

    J.E. Jakes; C.R. Frihart; J.F. Beecher; R.J. Moon; P.J. Resto; Z.H. Melgarejo; O.M. Saurez; H. Baumgart; A.A. Elmustafa; D.S. Stone

    2009-01-01

    Whenever a nanoindent is placed near an edge, such as the free edge of the specimen or heterophase interface intersecting the surface, the elastic discontinuity associated with the edge produces artifacts in the load-depth data. Unless properly handled in the data analysis, the artifacts can produce spurious results that obscure any real trends in properties as...

  13. Aircraft wing trailing-edge noise

    NASA Technical Reports Server (NTRS)

    Underwood, R. L.; Hodgson, T. H.

    1981-01-01

    The mechanism and sound pressure level of the trailing-edge noise for two-dimensional turbulent boundary layer flow was examined. Experiment is compared with current theory. A NACA 0012 airfoil of 0.61 m chord and 0.46 m span was immersed in the laminar flow of a low turbulence open jet. A 2.54 cm width roughness strip was placed at 15 percent chord from the leading edge on both sides of the airfoil as a boundary layer trip so that two separate but statistically equivalent turbulent boundary layers were formed. Tests were performed with several trailing-edge geometries with the upstream velocity U sub infinity ranging from a value of 30.9 m/s up to 73.4 m/s. Properties of the boundary layer for the airfoil and pressure fluctuations in the vicinity of the trailing-edge were examined. A scattered pressure field due to the presence of the trailing-edge was observed and is suggested as a possible sound producing mechanism for the trailing-edge noise.

  14. Spectral Analysis and Experimental Modeling of Ice Accretion Roughness

    NASA Technical Reports Server (NTRS)

    Orr, D. J.; Breuer, K. S.; Torres, B. E.; Hansman, R. J., Jr.

    1996-01-01

    A self-consistent scheme for relating wind tunnel ice accretion roughness to the resulting enhancement of heat transfer is described. First, a spectral technique of quantitative analysis of early ice roughness images is reviewed. The image processing scheme uses a spectral estimation technique (SET) which extracts physically descriptive parameters by comparing scan lines from the experimentally-obtained accretion images to a prescribed test function. Analysis using this technique for both streamwise and spanwise directions of data from the NASA Lewis Icing Research Tunnel (IRT) are presented. An experimental technique is then presented for constructing physical roughness models suitable for wind tunnel testing that match the SET parameters extracted from the IRT images. The icing castings and modeled roughness are tested for enhancement of boundary layer heat transfer using infrared techniques in a "dry" wind tunnel.

  15. Relation between skin micro-topography, roughness, and skin age.

    PubMed

    Trojahn, C; Dobos, G; Schario, M; Ludriksone, L; Blume-Peytavi, U; Kottner, J

    2015-02-01

    The topography of the skin surface consists of lines, wrinkles, and scales. Primary and secondary lines form a network like structure that may be identified as polygons. Skin surface roughness measurements are widely applied in dermatological research and practice but the relation between roughness parameters and their anatomical equivalents are unclear. This study aimed to investigate whether the number of closed polygons (NCP) per measurement field can be used as a reliable parameter to measure skin surface topography. For this purpose, we analysed the relation between skin surface roughness parameters and NCP in different age groups. Images of the volar forearm skin of 38 subjects (14 children, 12 younger, and 12 older adults) were obtained with the VisioScan VC98. The NCP was counted by three independent researchers and selected roughness parameters were measured. Interrater reliability of counting the number of closed polygons and correlations between NCP, roughness parameters, and age were calculated. The mean NCP/mm² in children was 3.1 (SD 1.1), in younger adults 1.0 (SD 0.7), and in older adults 1.0 (SD 0.9). The interrater reliability was 0.9. A negative correlation of NCP/mm² with age was observed, whereas measured roughness parameters were positively associated with age. NCP/mm² was weakly related to skin roughness. The NCP/mm² is a reproducible parameter for characterizing the skin surface topography. It is proposed as an additional parameter in dermatological research and practice because it represents distinct aspects of the cutaneous profile not covered by established roughness parameters. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Roughness effects in uncompensated antiferromagnets

    SciTech Connect

    Charilaou, M.; Hellman, F.

    2015-02-28

    Monte Carlo simulations show that roughness in uncompensated antiferromagnets decreases not just the surface magnetization but also the net magnetization and particularly strongly affects the temperature dependence. In films with step-type roughness, each step creates a new compensation front that decreases the global net magnetization. The saturation magnetization decreases non-monotonically with increasing roughness and does not scale with the surface area. Roughness in the form of surface vacancies changes the temperature-dependence of the magnetization; when only one surface has vacancies, the saturation magnetization will decrease linearly with surface occupancy, whereas when both surfaces have vacancies, the magnetization is negative and exhibits a compensation point at finite temperature, which can be tuned by controlling the occupancy. Roughness also affects the spin-texture of the surfaces due to long-range dipolar interactions and generates non-collinear spin configurations that could be used in devices to produce locally modified exchange bias. These results explain the strongly reduced magnetization found in magnetometry experiments and furthers our understanding of the temperature-dependence of exchange bias.

  17. Narrow line Seyfert 1 galaxies: where are the broad line regions?

    NASA Astrophysics Data System (ADS)

    Mao, Weiming; Hu, Chen; Wang, Jianmin; Bian, Weihao; Zhang, Shu; Zhao, Gang

    2010-12-01

    A sample consisting of 211 narrow line Seyfert 1 galaxies (NLS1s) with high quality spectra from the Sloan Digital Sky Survey (SDSS) is selected to explore where broad line regions are in these objects. We find that the H β profile can be fitted well by three (narrow, intermediate and broad) Gaussian components, and the FWHM ratios of the broad to the intermediate components hold a constant of 3.0 roughly for the entire sample. If the broad components originate from the region scaled by the well-determined H β reverberation mapping relation, we find that the intermediate components originate from the inner edge of the torus, which is scaled by dust K-band reverberation. We find that the IC and the BC are strongly linked dynamically, but the relation of their covering factors is much more relaxed, implying that both regions are clumpy.

  18. Edge Equilibrium Code (EEC) For Tokamaks

    SciTech Connect

    Li, Xujling

    2014-02-24

    The edge equilibrium code (EEC) described in this paper is developed for simulations of the near edge plasma using the finite element method. It solves the Grad-Shafranov equation in toroidal coordinate and uses adaptive grids aligned with magnetic field lines. Hermite finite elements are chosen for the numerical scheme. A fast Newton scheme which is the same as implemented in the equilibrium and stability code (ESC) is applied here to adjust the grids

  19. Robust Prediction of Hydraulic Roughness

    DTIC Science & Technology

    2011-03-01

    floodplain hydraulics, in particular hydraulic roughness, is critical for flood control concerns; however, diversity of vegetation type and...or particular flood return inter- val analyses. Field Assessment. Field assessment methods refer to those that do not rely on direct mea- surement or...material (riprap) Form Roughness Calculators Brownlie ( 1983 ) Lab, Field H, S, d50, σg 0.082 < R < 55.8 ft (0.025 < R < 17 m), 2.9 × 10-4 < d50

  20. [Efficacy and safety of vildagliptin as a second-line therapy vs other oral antidiabetic agents in patients with type 2 diabetes: Czech results within the worldwide prospective cohort EDGE study].

    PubMed

    Haluzík, M; Veselá, V; Gerle, J; Brada, M; Dohnalová, L; Edelsberger, T; Houdová, J

    2013-12-01

    Metformin monotherapy is recommended as initial treatment of type 2 diabetes. The selection of optimal second-line therapy that is often necessary due to the progressive nature of the disease is still a subject of ongoing discussions. The aim of the international EDGE (Effectiveness of Diabetes control with vildaGliptin and vildagliptin/mEtformin) study was to prospectively compare the efficacy and safety of vildagliptin vs other oral antidiabetic agents in patients with type 2 diabetes not adequately controlled on monotherapy in a real-life clinical setting. In this paper, we present the data of patients participating in the EDGE study in the Czech Republic. Patients with type 2 diabetes not adequately controlled on monotherapy were enrolled into the study, and randomised into either the vildagliptin arm or control arm with another OAD at the discretion of the treating physician. Patients with the addition of other incretin-based medications were not enrolled into the study. The efficiency was evaluated as a proportion of patients reaching the combined endpoint of decreasing HbA1c> 3 mmol/mol without hypoglycaemia, peripheral oedema or treatment termination due to gastrointestinal side effects during the 12 months of treatment. 654 patients were enrolled into the study in the Czech Republic. The mean age of the patients when enrolled into the study (vildagliptin group vs control group) was 59.5 ± 10.6 vs 63.7 ± 8.5 years, mean body mass index was 32.4 ± 5.7 vs 31.7 ± 6.5 kg/m2, mean HbA1c was 62 ± 12 vs 64 ± 11 mmol/mol. The probability of reaching the combined primary endpoint (calculated using a binary logistic regression model to calculate the odds ratios with 95% confidence intervals) was higher for vildagliptin regardless of baseline HbA1c or type of medication added in the control group. Primary endpoint was reached by 60.6 % of patients in the vildagliptin group vs 51.3 % of patients in the control group, odds ratio 1.46 (1.06, 1.99); p< 0.019. The

  1. 31 CFR 592.310 - Rough diamond.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Rough diamond. 592.310 Section 592.310... ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS General Definitions § 592.310 Rough diamond. The term rough diamond means any diamond that is unworked or simply sawn,...

  2. 31 CFR 592.310 - Rough diamond.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Rough diamond. 592.310 Section 592.310... ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS General Definitions § 592.310 Rough diamond. The term rough diamond means any diamond that is unworked or simply sawn,...

  3. 31 CFR 592.310 - Rough diamond.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Rough diamond. 592.310 Section 592.310... ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS General Definitions § 592.310 Rough diamond. The term rough diamond means any diamond that is unworked or simply sawn,...

  4. 31 CFR 592.310 - Rough diamond.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Rough diamond. 592.310 Section 592.310... ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS General Definitions § 592.310 Rough diamond. The term rough diamond means any diamond that is unworked or simply sawn,...

  5. 31 CFR 592.310 - Rough diamond.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Rough diamond. 592.310 Section 592... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS General Definitions § 592.310 Rough diamond. The term rough diamond means any diamond that is unworked or simply...

  6. Roughness of stable, armored gravel beds

    NASA Astrophysics Data System (ADS)

    Gomez, Basil

    1993-11-01

    The grain roughness of stable armored beds that formed in a laboratory flume under a range of steady flow conditions on rounded, flat and angular gravel is analyzed. Gravel roughness geometry is determined from bed surface profiles and vertical photographs. These techniques have been employed in field situations. Thus the methodology is potentially applicable to the analysis of grain roughness in natural gravel bed channels. The description of representative roughness geometry is also analogous to that used to characterize artificial roughness arrays. Armor roughness increases with increasing flow. Armored surfaces composed of angular gravel are roughest, and surfaces formed of flat gravel offer least resistance to the flow. Stable armored beds may exhibit a tendency to maximize the ratio of the shear due to drag on representative roughness elements to total shear. Roughness concentration is strongly correlated with the energy slope, and there is a linear increase in equivalent roughness height with increasing roughness concentration. The friction factor for an armored surface varies in a linear manner with representative roughness geometry. The equation defining this relation is probably similar to that used to characterize variations in the friction factor with artificial roughness geometry at low roughness concentrations. However, to reconcile the relations for artificial and natural roughness completely, it may be necessary to explicitly consider the contribution to flow resistance made by roughness shape, background roughness, and blocking in shallow flows.

  7. Plant Communities of Rough Rock.

    ERIC Educational Resources Information Center

    Jacobs, Linda

    A unit of study on plants grown in the Navajo community of Rough Rock, Arizona, is presented in sketches providing the common Navajo name for the plant, a literal English translation, the English name of the plant, and the Latin name. A brief description of each plant includes where the plant grows, how the Navajos use the plant, and the color and…

  8. Simulation for Rough Mill Options

    Treesearch

    Janice K. Wiedenbeck

    1992-01-01

    How is rough mill production affected by lumber length? Lumber grade? Cutting quality? Cutting sizes? How would equipment purchase plans be prioritized? How do personnel shifts affect system productivity? What effect would a reduction in machine set-up time have on material flow? Simulation modeling is being widely used in many industries to provide valuable insight...

  9. Plant Communities of Rough Rock.

    ERIC Educational Resources Information Center

    Jacobs, Linda

    A unit of study on plants grown in the Navajo community of Rough Rock, Arizona, is presented in sketches providing the common Navajo name for the plant, a literal English translation, the English name of the plant, and the Latin name. A brief description of each plant includes where the plant grows, how the Navajos use the plant, and the color and…

  10. Tasting edge effects

    NASA Astrophysics Data System (ADS)

    Bocquet, Lydéric

    2007-02-01

    We show that the baking of potato wedges constitutes a crunchy example of edge effects, which are usually demonstrated in electrostatics. A simple model of the diffusive transport of water vapor around the potato wedges shows that the water vapor flux diverges at the sharp edges in analogy with its electrostatic counterpart. This increased evaporation at the edges leads to the crispy taste of these parts of the potatoes.

  11. Human roughness perception and possible factors effecting roughness sensation.

    PubMed

    Aktar, Tugba; Chen, Jianshe; Ettelaie, Rammile; Holmes, Melvin; Henson, Brian

    2017-06-01

    Surface texture sensation is significant for business success, in particular for solid surfaces for most of the materials; including foods. Mechanisms of roughness perception are still unknown, especially under different conditions such as lubricants with varying viscosities, different temperatures, or under different force loads during the observation of the surface. This work aims to determine the effect of those unknown factors, with applied sensory tests on 62 healthy participants. Roughness sensation of fingertip was tested under different lubricants including water and diluted syrup solutions at room temperature (25C) and body temperature (37C) by using simple pair-wise comparison to observe the just noticeable difference threshold and perception levels. Additionally, in this research applied force load during roughness observation was tested with pair-wise ranking method to illustrate its possible effect on human sensation. Obtained results showed that human's capability of roughness discrimination reduces with increased viscosity of the lubricant, where the influence of the temperature was not found to be significant. Moreover, the increase in the applied force load showed an increase in the sensitivity of roughness discrimination. Observed effects of the applied factors were also used for estimating the oral sensation of texture during eating. These findings are significant for our fundamental understanding to texture perception, and for the development of new food products with controlled textural features. Texture discrimination ability, more specifically roughness discrimination capability, is a significant factor for preference and appreciation for a wide range of materials, including food, furniture, or fabric. To explore the mechanism of sensation capability through tactile senses, it is necessary to identify the relevant factors and define characteristics that dominate the process involved. The results that will be obtained under these principles

  12. PVMaT cost reductions in the EFG high volume PV manufacturing line: Annual report, 5 August 1998--4 August 1999[PhotoVoltaic Manufacturing Technology, Edge-defined Film-fed Growth

    SciTech Connect

    Bathey, B.; Brown, B.; Cao, J.; Ebers, S.; Gonsiorawski, R.; Heath, B.; Kalejs, J.; Kardauskas, M.; Mackintosh, B.; Ouellette, M.; Piwczyk, B.; Rosenblum, M.; Southimath, B.

    1999-11-16

    This report describes work performed by ASE Americas researchers during the first year of this Photovoltaic Manufacturing Technology 5A2 program. Significant accomplishments in each of three task are as follows. Task 1--Manufacturing Systems: Researchers completed key node analysis, started statistical process control (SPC) charting, carried out design-of-experiment (DoE) matrices on the cell line to optimize efficiencies, performed a capacity and bottleneck study, prepared a baseline chemical waste analysis report, and completed writing of more than 50% of documentation and statistical sections of ISO 9000 procedures. A highlight of this task is that cell efficiencies in manufacturing were increased by 0.4%--0.5% absolute, to an average in excess of 14.2%, with the help of DoE and SPC methods. Task 2--Low-Cost Processes: Researchers designed, constructed, and tested a 50-cm-diameter, edge-defined, film-fed growth (EFG) cylinder crystal growth system to successfully produce thin cylinders up to 1.2 meters in length; completed a model for heat transfer; successfully deployed new nozzle designs and used them with a laser wafer-cutting system with the potential to decrease cutting labor costs by 75% and capital costs by 2X; achieved laser-cutting speeds of up to 8X and evaluation of this system is proceeding in production; identified laser-cutting conditions that reduce damage for both Q-switched Nd:YAG and copper-vapor lasers with the help of a breakthrough in fundamental understanding of cutting with these short-pulse-length lasers; and found that bulk EFG material lifetimes are optimized when co-firing of silicon nitride and aluminum is carried out with rapid thermal processing (RTP). Task 3--Flexible Manufacturing: Researchers improved large-volume manufacturing of 10-cm {times} 15-cm EFG wafers by developing laser-cutting fixtures, adapting carriers and fabricating adjustable racks for etching and rinsing facilities, and installing a high-speed data collection

  13. Heat Transfer Enhancement by Finned Heat Sinks with Micro-structured Roughness

    NASA Astrophysics Data System (ADS)

    Ventola, L.; Chiavazzo, E.; Calignano, F.; Manfredi, D.; Asinari, P.

    2014-04-01

    We investigated the benefits of micro-structured roughness on heat transfer performance of heat sinks, cooled by forced air. Heat sinks in aluminum alloy by direct metal laser sintering (DMLS) manufacturing technique were fabricated; values of the average surface roughness Ra from 1 to 25 microns (standard milling leads to roughness around 1 micron) under turbulent regimes (Reynolds number based on heating edge from 3000 to 17000) have been explored. An enhancement of 50% in thermal performances with regards to standard manufacturing was observed. This may open the way for huge boost in the technology of electronic cooling by DMLS.

  14. PICNIC PAVILION JUST BEYOND THE WESTERN EDGE OF THE BOTANIC ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    PICNIC PAVILION JUST BEYOND THE WESTERN EDGE OF THE BOTANIC GARDEN. THIS PAVILION IS ROUGHLY LOCATED ON THE SITE OF "BARTRAM HALL," ANDREW EASTLAKE'S ITALIANATE VILLA DESIGNED BY NOTED PHILADELPHIA ARCHITECT SAMUEL SLOAN AND CONSTRUCTED IN 1850-1851 - John Bartram House & Garden, 54th Street & Lindbergh Boulevard, Philadelphia, Philadelphia County, PA

  15. The Long Range Persistence of Wakes Behind a Row of Roughness Elements

    NASA Technical Reports Server (NTRS)

    Goldstein, M. E.; Sescu, Adrian; Duck, Peter W.; Choudhari, Meelan

    2010-01-01

    We consider a periodic array of relatively small roughness elements whose spanwise separation is of the order of the local boundary-layer thickness and construct a local asymptotic high-Reynolds-number solution that is valid in the vicinity of the roughness. The resulting flow decays on the very short streamwise length scale of the roughness, but the solution eventually becomes invalid at large downstream distances and a new solution has to be constructed in the downstream region. This latter result shows that the roughness-generated wakes can persist over very long streamwise distances, which are much longer than the distance between the roughness elements and the leading edge. Detailed numerical results are given for the far wake structure.

  16. The Long Range Persistence of Wakes Behind a Row of Roughness Elements

    NASA Technical Reports Server (NTRS)

    Goldstein, M. E.; Sescu, Adrian; Duck, Peter W.; Choudhari, Meelan

    2010-01-01

    We consider a periodic array of relatively small roughness elements whose spanwise separation is of the order of the local boundary-layer thickness and construct a local asymptotic high-Reynolds-number solution that is valid in the vicinity of the roughness. The resulting flow decays on the very short streamwise length scale of the roughness, but the solution eventually becomes invalid at large downstream distances and a new solution has to be constructed in the downstream region. This latter result shows that the roughness-generated wakes can persist over very long streamwise distances, which are much longer than the distance between the roughness elements and the leading edge. Detailed numerical results are given for the far wake structure.

  17. Electromagnetic Scattering from Randomly Rough Surfaces with Hybrid FEM/BIE

    NASA Astrophysics Data System (ADS)

    Li, Jie; Guo, Li-Xin; He, Qiong; Wei, Bing

    2011-10-01

    The hybrid finite element method (FEM) together with the boundary integral equation (BIE) is firstly applied to scattering from a conducting rough surface. The BIE is used as the truncation boundary condition for the special unbounded half space, whereas the FEM is used to solve the governing equation in the region surrounded by a rough surface and artificial boundary. Tapered wave incidence is employed to cancel the so-called “edge effect". A hybrid FEM/BIE formulation for generalized one-dimensional conducting rough surface scattering is presented, as well as examples that evaluate its validity compared to the method of moments. The bistatic scattering coefficients of a Gaussian rough surface are calculated for transverse-magnetic wave incidence. Conclusions are reached after analyzing the scattering patterns of rough surfaces with different rms heights and correlation lengths

  18. Crossover between magnetic and electric edges in quantum Hall systems

    NASA Astrophysics Data System (ADS)

    Nogaret, Alain; Mondal, Puja; Kumar, Ankip; Ghosh, Sankalpa; Beere, Harvey; Ritchie, David

    2017-08-01

    We report on the transition from magnetic edge to electric edge transport in a split magnetic gate device which applies a notch magnetic field to a two-dimensional electron gas. The gate bias allows tuning the overlap of magnetic and electric edge wave functions on the scale of the magnetic length. Conduction at the magnetic edges, in the two-dimensional bulk, is found to compete with conduction at the electric edges until the magnetic edges become depleted. Current lines then move to the electrostatic edges as in the conventional quantum Hall picture. The conductivity was modeled using the quantum Boltzmann equation in the exact hybrid potential. The theory predicts the features of the bulk-edge crossover, in good agreement with experiment.

  19. Continuum Gyrokinetic Edge New Technology

    SciTech Connect

    Dorr, M. R.; Hittinger, J. A.; Dorf, M.; Cohen, R.; Ghosh, D.; Lee, W.; Reynolds, C.

    2016-05-02

    COGENT is a simulation code that models the plasma evolution in the edge region of a tokamak fusion reactor, from the open field line scrape-off layer, across the separatrix, and into the core. The model is based on the 4D gyrokinetic closure of the kinetic equations for a plasma coupled to an electrostatic potential field. The background magnetic field is prescribed either analytically or generated from experimental data, and the grid is aligned with magnetic flux surfaces. Multiple collision operator options are provided, from Krook to fully nonlinear Fokker-Planck.

  20. Surface roughness effects with solid lubricants dispersed in mineral oils

    NASA Technical Reports Server (NTRS)

    Cusano, C.; Goglia, P. R.; Sliney, H. E.

    1983-01-01

    The lubricating effectiveness of solid-lubricant dispersions are investigated in both point and line contacts using surfaces with both random and directional roughness characteristics. Friction and wear data obtained at relatively low speeds and at room temperature, indicate that the existence of solid lubricants such as graphite, MoS2, and PTFE in a plain mineral oil generally will not improve the effectiveness of the oil as a lubricant for such surfaces. Under boundary lubrication conditions, the friction force, as a function of time, initially depends upon the directional roughness properties of the contacting surfaces irrespective of whether the base oil or dispersions are used as lubricants.

  1. Surface roughness effects with solid lubricants dispersed in mineral oils

    NASA Technical Reports Server (NTRS)

    Cusano, C.; Goglia, P. R.; Sliney, H. E.

    1983-01-01

    The lubricating effectiveness of solid-lubricant dispersions are investigated in both point and line contacts using surfaces with both random and directional roughness characteristics. Friction and wear data obtained at relatively low speeds and at room temperature, indicate that the existence of solid lubricants such as graphite, MoS2, and PTFE in a plain mineral oil generally will not improve the effectiveness of the oil as a lubricant for such surfaces. Under boundary lubrication conditions, the friction force, as a function of time, initially depends upon the directional roughness properties of the contacting surfaces irrespective of whether the base oil or dispersions are used as lubricants.

  2. Effect of surface roughness on helicopter main rotor blade

    NASA Astrophysics Data System (ADS)

    Rohizan, W. N. W.; Rafie, A. S. M.; Harmin, M. Y.; Ciang, C. C.

    2016-10-01

    This paper describes the effect of surface roughness when applied on helicopter main rotor blade. The aim is to prove that surface roughness can be used as a simple and inexpensive method to achieve better flight performance such as enhanced thrust and/or reduced power requirement. The research was done experimentally, using scaled model of Eurocopter AS350 Ecureuil. Smooth profile of the main rotor blade was modified by applying surface roughness on the upper and lower camber in transition and turbulent boundary layer region, starting from 25% of chord length and extending up to the trailing edge (TE). This study was conducted with the conditions of a vertical flight (particularly in hover condition) since this is a high powerconsuming flight regime for helicopter. The experiment resulted in lower power requirement but at the expense of reduced thrust at the middle collective pitch level. At upper range of the collective pitch level, surface roughness was seen to delay the stall angle as well as increase the lift in the stall region. Meanwhile, at lower pitch level, there was an increase in thrust-to-power ratio.

  3. Topographic complexity and roughness of a tropical benthic seascape

    NASA Astrophysics Data System (ADS)

    Zawada, David G.; Piniak, Gregory A.; Hearn, Clifford J.

    2010-07-01

    Topographic complexity is a fundamental structural property of benthic marine ecosystems that exists across all scales and affects a multitude of processes. Coral reefs are a prime example, for which this complexity has been found to impact water flow, species diversity, nutrient uptake, and wave-energy dissipation, among other properties. Despite its importance, only limited assessments are available regarding the distribution or range of topographic complexity within or between benthic communities. Here, we show substantial variability in topographic complexity over the entire inner-shelf seascape of a tropical island. Roughness, estimated in terms of fractal dimension, served as a proxy for topographic complexity, and was computed for linear transects (DT), as well as the benthic surface (DS). Spatial variability in both DT and DS was correlated with the known distribution of benthic cover types in the seascape. Transect roughness values ranged from 1.0 to 1.7, with features along the shelf edge being markedly anisotropic with an along-shore bias, whereas regions with high scleractinian coral cover were nearly isotropic and exhibited minimal directional bias. Surface-roughness values ranged from 2.0 in predominantly hardbottom areas with low coral cover to 2.5 in areas with high coral cover. Quantifying roughness across the substrates and biological communities for an entire seascape provides a synoptic view of its spatial variability at scales appropriate for numerous research efforts, including ecosystem studies, parameterizing hydrodynamic models, and designing monitoring programs.

  4. Supersonic Leading Edge Receptivity

    NASA Technical Reports Server (NTRS)

    Maslov, Anatoly A.

    1998-01-01

    This paper describes experimental studies of leading edge boundary layer receptivity for imposed stream disturbances. Studies were conducted in the supersonic T-325 facility at ITAM and include data for both sharp and blunt leading edges. The data are in agreement with existing theory and should provide guidance for the development of more complete theories and numerical computations of this phenomena.

  5. The Edge, Fall 1999.

    ERIC Educational Resources Information Center

    Edge, 1999

    1999-01-01

    "The Edge" is a Canadian publication for youth. The mandate of the Edge is to support and celebrate all career journeys embraced by youth. This issue contains career profile articles covering three jobs: crane operator, indoor climbing instructor, and product certification tester. Career trends and the state of today's workplace are also…

  6. Exploring Valued-Added Options - Edge-Glued Panels and Blanks Offer Value-Added Opportunities

    Treesearch

    Bob Smith; Philip A. Araman

    1997-01-01

    As sawmills search for new opportunities to add value to rough sawn lumber, many consider producing dimension parts as one solution. Assembling dimension parts into edge-glued panels or standard blanks can add even further value. Blanks are defined as pieces of solid wood (which may be edge-glued) that are manufactured to a predetermined size. This article discusses...

  7. Noise of sliding rough contact

    NASA Astrophysics Data System (ADS)

    Le Bot, Alain

    2017-01-01

    This article is a discussion about the origin of friction noise produced when rubbing solids having rough surfaces. We show that noise emerges from numerous impacts into the contact between antagonist asperities of surfaces. Prediction of sound sources reduces to a statistical problem of contact mechanics. On the other hand, contact is also responsible of dissipation of vibration. This leads to the paradoxical result that the noise may not be proportional to the number of sources.

  8. Sensing roughness and polish direction

    NASA Astrophysics Data System (ADS)

    Jakobsen, M. L.; Olesen, A. S.; Larsen, H. E.; Stubager, J.; Hanson, S. G.; Pedersen, T. F.; Pedersen, H. C.

    2016-04-01

    As a part of the work carried out on a project supported by the Danish council for technology and innovation, we have investigated the option of smoothing standard CNC machined surfaces. In the process of constructing optical prototypes, involving custom-designed optics, the development cost and time consumption can become relatively large numbers in a research budget. Machining the optical surfaces directly is expensive and time consuming. Alternatively, a more standardized and cheaper machining method can be used, but then the object needs to be manually polished. During the polishing process the operator needs information about the RMS-value of the surface roughness and the current direction of the scratches introduces by the polishing process. The RMS-value indicates to the operator how far he is from the final finish, and the scratch orientation is often specified by the customer in order to avoid complications during the casting process. In this work we present a method for measuring the RMS-values of the surface roughness while simultaneously determining the polishing direction. We are mainly interested in the RMS-values in the range from 0 - 100 nm, which corresponds to the finish categories of A1, A2 and A3. Based on simple intensity measurements we estimates the RMS-value of the surface roughness, and by using a sectioned annual photo-detector to collect the scattered light we can determine the direction of polishing and distinguish light scattered from random structures and light scattered from scratches.

  9. A robust sub-pixel edge detection method of infrared image based on tremor-based retinal receptive field model

    NASA Astrophysics Data System (ADS)

    Gao, Kun; Yang, Hu; Chen, Xiaomei; Ni, Guoqiang

    2008-03-01

    Because of complex thermal objects in an infrared image, the prevalent image edge detection operators are often suitable for a certain scene and extract too wide edges sometimes. From a biological point of view, the image edge detection operators work reliably when assuming a convolution-based receptive field architecture. A DoG (Difference-of- Gaussians) model filter based on ON-center retinal ganglion cell receptive field architecture with artificial eye tremors introduced is proposed for the image contour detection. Aiming at the blurred edges of an infrared image, the subsequent orthogonal polynomial interpolation and sub-pixel level edge detection in rough edge pixel neighborhood is adopted to locate the foregoing rough edges in sub-pixel level. Numerical simulations show that this method can locate the target edge accurately and robustly.

  10. Rough and partially-cemented fracture permeability

    NASA Astrophysics Data System (ADS)

    Landry, C. J.; Eichhubl, P.; Prodanovic, M.

    2016-12-01

    Numerical studies of mass transport in fractured rock, such as discrete fracture network models, use models to assign estimates of permeability to individual fractures. These fracture permeability models typically employ statistical moments of the fracture aperture distribution to estimate permeability. Although it is known that these fracture permeability models are in error, the quantification of this error is limited. We use a digital rock physics workflow to quantify this error in four fracture samples, a barren artificially-induced fracture in sandstone, a calcite-lined fracture sampled from outcrop, and two quartz-bridged fractures sampled from reservoir core. Each of the fracture samples is imaged using three-dimensional x-ray computed microtomography. The images are then processed, segmented and used in a lattice-Boltzmann-method-based flow simulation. We also vary the kinematic apertures of the barren and calcite-lined fractures through digital dilatation and closure in order to investigate sensitivity to the relative fracture roughness. We define the scalar error, F, between the actual permeability determined from simulation, kLB, and that predicted using the fracture permeability model of Zimmerman and Bodvarsson (1996), kZB, as, F±1=kZB/kLB. Although the pore space shape of the fractures appears quite different, the scalar error as a function of relative roughness is found to be similar for all fracture samples investigated, with a maximum of approximately 2. Considering two-dimensional cross-sections of fractures are more readily available than three-dimensional images we then plot the scalar error as a function of relative roughness and the number of observations measured from two-dimensional images (width of fracture analyzed). In general, the rougher the fracture, the greater the number of observations that are required to define the statistical moment inputs for the fracture permeability model. We use these results to approximate the width of the

  11. Miniature Trailing Edge Effector for Aerodynamic Control

    NASA Technical Reports Server (NTRS)

    Lee, Hak-Tae (Inventor); Bieniawski, Stefan R. (Inventor); Kroo, Ilan M. (Inventor)

    2008-01-01

    Improved miniature trailing edge effectors for aerodynamic control are provided. Three types of devices having aerodynamic housings integrated to the trailing edge of an aerodynamic shape are presented, which vary in details of how the control surface can move. A bucket type device has a control surface which is the back part of a C-shaped member having two arms connected by the back section. The C-shaped section is attached to a housing at the ends of the arms, and is rotatable about an axis parallel to the wing trailing edge to provide up, down and neutral states. A flip-up type device has a control surface which rotates about an axis parallel to the wing trailing edge to provide up, down, neutral and brake states. A rotating type device has a control surface which rotates about an axis parallel to the chord line to provide up, down and neutral states.

  12. Cross Flow Effects on Glaze Ice Roughness Formation

    NASA Technical Reports Server (NTRS)

    Tsao, Jen-Ching

    2004-01-01

    The present study examines the impact of large-scale cross flow on the creation of ice roughness elements on the leading edge of a swept wing under glaze icing conditions. A three-dimensional triple-deck structure is developed to describe the local interaction of a 3 D air boundary layer with ice sheets and liquid films. A linear stability analysis is presented here. It is found that, as the sweep angle increases, the local icing instabilities enhance and the most linearly unstable modes are strictly three dimensional.

  13. Intelligent System Development Using a Rough Sets Methodology

    NASA Technical Reports Server (NTRS)

    Anderson, Gray T.; Shelton, Robert O.

    1997-01-01

    The purpose of this research was to examine the potential of the rough sets technique for developing intelligent models of complex systems from limited information. Rough sets a simple but promising technology to extract easily understood rules from data. The rough set methodology has been shown to perform well when used with a large set of exemplars, but its performance with sparse data sets is less certain. The difficulty is that rules will be developed based on just a few examples, each of which might have a large amount of noise associated with them. The question then becomes, what is the probability of a useful rule being developed from such limited information? One nice feature of rough sets is that in unusual situations, the technique can give an answer of 'I don't know'. That is, if a case arises that is different from the cases the rough set rules were developed on, the methodology can recognize this and alert human operators of it. It can also be trained to do this when the desired action is unknown because conflicting examples apply to the same set of inputs. This summer's project was to look at combining rough set theory with statistical theory to develop confidence limits in rules developed by rough sets. Often it is important not to make a certain type of mistake (e.g., false positives or false negatives), so the rules must be biased toward preventing a catastrophic error, rather than giving the most likely course of action. A method to determine the best course of action in the light of such constraints was examined. The resulting technique was tested with files containing electrical power line 'signatures' from the space shuttle and with decompression sickness data.

  14. Superfluid vortex formation at rough boundaries

    SciTech Connect

    Krasnov, Y.K.

    1980-10-01

    It is shown that roughness of a superfluid boundary lowers the surface energy barrier, which prevents the detachment of quantized vortices from the boundary under the action of the Magnus force exerted by the external flow past the roughness.

  15. Fractal study and simulation of fracture roughness

    SciTech Connect

    Kumar, S.; Bodvarsson, G.S. )

    1990-05-01

    This study examines the roughness profiles of the surfaces of fractures and faults by using concepts from fractal geometry. Relationships between fractal characteristics of profiles and isotropic surfaces are analytically developed and a deterministic representation of the roughness is examined.

  16. Molecular dynamics simulation of nanobubble nucleation on rough surfaces

    NASA Astrophysics Data System (ADS)

    Liu, Yawei; Zhang, Xianren

    2017-04-01

    Here, we study how nanobubbles nucleate on rough hydrophobic surfaces, using long-time standard simulations to directly observe the kinetic pathways and using constrained simulations combined with the thermodynamic integration approach to quantitatively evaluate the corresponding free energy changes. Both methods demonstrate that a two-step nucleation route involving the formation of an intermediate state is thermodynamically favorable: at first, the system transforms from the Wenzel state (liquid being in full contact with the solid surface) to the Cassie state (liquid being in contact with the peaks of the rough surface) after gas cavities occur in the grooves (i.e., the Wenzel-to-Cassie transition); then, the gas cavities coalesce and form a stable surface nanobubble with pinned contact lines (i.e., the Cassie-to-nanobubble transition). Additionally, the free energy barriers for the two transitions show opposing dependencies on the degree of surface roughness, indicating that the surfaces with moderate roughness are favorable for forming stable surface nanobubbles. Moreover, the simulation results also reveal the coexistence and transition between the Wenzel, Cassie, and nanobubble states on rough surfaces.

  17. Surface roughness monitoring by singular spectrum analysis of vibration signals

    NASA Astrophysics Data System (ADS)

    García Plaza, E.; Núñez López, P. J.

    2017-02-01

    This study assessed two methods for enhanced surface roughness (Ra) monitoring based on the application of singular spectrum analysis (SSA) to vibrations signals generated in workpiece-cutting tool interaction in CNC finish turning operations i.e., the individual analysis of principal components (I-SSA), and the grouping analysis of correlated principal components (G-SSA). Singular spectrum analysis is a non-parametric technique of time series analysis that decomposes a signal into a set of independent additive time series referred to as principal components. A number of experiments with different cutting conditions were performed to assess surface roughness monitoring using both of these methods. The results show that singular spectrum analysis of vibration signal processing discriminated the frequency ranges effective for predicting surface roughness. Grouping analysis of correlated principal components (G-SSA) proved to be the most efficient method for monitoring surface roughness, with optimum prediction and reliability results at a lower analytical-computational cost. Finally, the results show that singular spectrum analysis is an ideal method for analyzing vibration signals applied to the on-line monitoring of surface roughness.

  18. Molecular dynamics simulation of nanobubble nucleation on rough surfaces.

    PubMed

    Liu, Yawei; Zhang, Xianren

    2017-04-28

    Here, we study how nanobubbles nucleate on rough hydrophobic surfaces, using long-time standard simulations to directly observe the kinetic pathways and using constrained simulations combined with the thermodynamic integration approach to quantitatively evaluate the corresponding free energy changes. Both methods demonstrate that a two-step nucleation route involving the formation of an intermediate state is thermodynamically favorable: at first, the system transforms from the Wenzel state (liquid being in full contact with the solid surface) to the Cassie state (liquid being in contact with the peaks of the rough surface) after gas cavities occur in the grooves (i.e., the Wenzel-to-Cassie transition); then, the gas cavities coalesce and form a stable surface nanobubble with pinned contact lines (i.e., the Cassie-to-nanobubble transition). Additionally, the free energy barriers for the two transitions show opposing dependencies on the degree of surface roughness, indicating that the surfaces with moderate roughness are favorable for forming stable surface nanobubbles. Moreover, the simulation results also reveal the coexistence and transition between the Wenzel, Cassie, and nanobubble states on rough surfaces.

  19. Characterization of Ice Roughness From Simulated Icing Encounters

    NASA Technical Reports Server (NTRS)

    Anderson, David N.; Shin, Jaiwon

    1997-01-01

    Detailed measurements of the size of roughness elements on ice accreted on models in the NASA Lewis Icing Research Tunnel (IRT) were made in a previous study. Only limited data from that study have been published, but included were the roughness element height, diameter and spacing. In the present study, the height and spacing data were found to correlate with the element diameter, and the diameter was found to be a function primarily of the non-dimensional parameters freezing fraction and accumulation parameter. The width of the smooth zone which forms at the leading edge of the model was found to decrease with increasing accumulation parameter. Although preliminary, the success of these correlations suggests that it may be possible to develop simple relationships between ice roughness and icing conditions for use in ice-accretion-prediction codes. These codes now require an ice-roughness estimate to determine convective heat transfer. Studies using a 7.6-cm-diameter cylinder and a 53.3-cm-chord NACA 0012 airfoil were also performed in which a 1/2-min icing spray at an initial set of conditions was followed by a 9-1/2-min spray at a second set of conditions. The resulting ice shape was compared with that from a full 10-min spray at the second set of conditions. The initial ice accumulation appeared to have no effect on the final ice shape. From this result, it would appear the accreting ice is affected very little by the initial roughness or shape features.

  20. The digital step edge

    NASA Technical Reports Server (NTRS)

    Haralick, R. M.

    1982-01-01

    The facet model was used to accomplish step edge detection. The essence of the facet model is that any analysis made on the basis of the pixel values in some neighborhood has its final authoritative interpretation relative to the underlying grey tone intensity surface of which the neighborhood pixel values are observed noisy samples. Pixels which are part of regions have simple grey tone intensity surfaces over their areas. Pixels which have an edge in them have complex grey tone intensity surfaces over their areas. Specially, an edge moves through a pixel only if there is some point in the pixel's area having a zero crossing of the second directional derivative taken in the direction of a non-zero gradient at the pixel's center. To determine whether or not a pixel should be marked as a step edge pixel, its underlying grey tone intensity surface was estimated on the basis of the pixels in its neighborhood.

  1. Flap Edge Aeroacoustic Measurements and Predictions

    NASA Technical Reports Server (NTRS)

    Brooks, Thomas F.; Humphreys, William M., Jr.

    2000-01-01

    An aeroacoustic model test has been conducted to investigate the mechanisms of sound generation on high-lift wing configurations. This paper presents an analysis of flap side-edge noise, which is often the most dominant source. A model of a main element wing section with a half-span flap was tested at low speeds of up to a Mach number of 0.17, corresponding to a wing chord Reynolds number of approximately 1.7 million. Results are presented for flat (or blunt), flanged, and round flap-edge geometries, with and without boundary-layer tripping, deployed at both moderate and high flap angles. The acoustic database is obtained from a Small Aperture Directional Array (SADA) of microphones, which was constructed to electronically steer to different regions of the model and to obtain farfield noise spectra and directivity from these regions. The basic flap-edge aerodynamics is established by static surface pressure data, as well as by Computational Fluid Dynamics (CFD) calculations and simplified edge flow analyses. Distributions of unsteady pressure sensors over the flap allow the noise source regions to be defined and quantified via cross-spectral diagnostics using the SADA output. It is found that shear layer instability and related pressure scatter is the primary noise mechanism. For the flat edge flap, two noise prediction methods based on unsteady surface pressure measurements are evaluated and compared to measured noise. One is a new causality spectral approach developed here. The other is a new application of an edge-noise scatter prediction method. The good comparisons for both approaches suggest that much of the physics is captured by the prediction models. Areas of disagreement appear to reveal when the assumed edge noise mechanism does not fully define the noise production. For the different edge conditions, extensive spectra and directivity are presented. Significantly, for each edge configuration, the spectra for different flow speeds, flap angles, and

  2. Flap Edge Aeroacoustic Measurements and Predictions

    NASA Technical Reports Server (NTRS)

    Brooks, Thomas F.; Humphreys, William M., Jr.

    2000-01-01

    An aeroacoustic model test has been conducted to investigate the mechanisms of sound generation on high-lift wing configurations. This paper presents an analysis of flap side-edge noise, which is often the most dominant source. A model of a main element wing section with a half-span flap was tested at low speeds of up to a Mach number of 0.17, corresponding to a wing chord Reynolds number of approximately 1.7 million. Results are presented for flat (or blunt), flanged, and round flap-edge geometries, with and without boundary-layer tripping, deployed at both moderate and high flap angles. The acoustic database is obtained from a Small Aperture Directional Array (SADA) of microphones, which was constructed to electronically steer to different regions of the model and to obtain farfield noise spectra and directivity from these regions. The basic flap-edge aerodynamics is established by static surface pressure data, as well as by Computational Fluid Dynamics (CFD) calculations and simplified edge flow analyses. Distributions of unsteady pressure sensors over the flap allow the noise source regions to be defined and quantified via cross-spectral diagnostics using the SADA output. It is found that shear layer instability and related pressure scatter is the primary noise mechanism. For the flat edge flap, two noise prediction methods based on unsteady-surface-pressure measurements are evaluated and compared to measured noise. One is a new causality spectral approach developed here. The other is a new application of an edge-noise scatter prediction method. The good comparisons for both approaches suggest that much of the physics is captured by the prediction models. Areas of disagreement appear to reveal when the assumed edge noise mechanism does not fully define, the noise production. For the different edge conditions, extensive spectra and directivity are presented. Significantly, for each edge configuration, the spectra for different flow speeds, flap angles, and

  3. Intelligent Information Retrieval Using Rough Set Approximations.

    ERIC Educational Resources Information Center

    Srinivasan, Padmini

    1989-01-01

    Describes rough sets theory and discusses the advantages it offers for information retrieval, including the implicit inclusion of Boolean logic, term weighting, ranked retrieval output, and relevance feedback. Rough set formalism is compared to Boolean, vector, and fuzzy models of information retrieval and a small scale evaluation of rough sets is…

  4. 7 CFR 51.1873 - Slightly rough.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Slightly rough. 51.1873 Section 51.1873 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Fresh Tomatoes 1 Definitions § 51.1873 Slightly rough. Slightly rough means that the tomato is...

  5. 7 CFR 51.1873 - Slightly rough.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Slightly rough. 51.1873 Section 51.1873 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Fresh Tomatoes 1 Definitions § 51.1873 Slightly rough. Slightly rough means that the tomato is...

  6. 7 CFR 51.1873 - Slightly rough.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Slightly rough. 51.1873 Section 51.1873 Agriculture..., CERTIFICATION, AND STANDARDS) United States Standards for Fresh Tomatoes 1 Definitions § 51.1873 Slightly rough. Slightly rough means that the tomato is not decidedly ridged or grooved. ...

  7. 7 CFR 51.1873 - Slightly rough.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Slightly rough. 51.1873 Section 51.1873 Agriculture..., CERTIFICATION, AND STANDARDS) United States Standards for Fresh Tomatoes 1 Definitions § 51.1873 Slightly rough. Slightly rough means that the tomato is not decidedly ridged or grooved. ...

  8. Electrokinetic transport in microchannels with random roughness

    SciTech Connect

    Wang, Moran; Kang, Qinjun

    2008-01-01

    We present a numerical framework to model the electrokinetic transport in microchannels with random roughness. The three-dimensional microstructure of the rough channel is generated by a random generation-growth method with three statistical parameters to control the number density, the total volume fraction, and the anisotropy characteristics of roughness elements. The governing equations for the electrokinetic transport are solved by a high-efficiency lattice Poisson?Boltzmann method in complex geometries. The effects from the geometric characteristics of roughness on the electrokinetic transport in microchannels are therefore modeled and analyzed. For a given total roughness volume fraction, a higher number density leads to a lower fluctuation because of the random factors. The electroosmotic flow rate increases with the roughness number density nearly logarithmically for a given volume fraction of roughness but decreases with the volume fraction for a given roughness number density. When both the volume fraction and the number density of roughness are given, the electroosmotic flow rate is enhanced by the increase of the characteristic length along the external electric field direction but is reduced by that in the direction across the channel. For a given microstructure of the rough microchannel, the electroosmotic flow rate decreases with the Debye length. It is found that the shape resistance of roughness is responsible for the flow rate reduction in the rough channel compared to the smooth channel even for very thin double layers, and hence plays an important role in microchannel electroosmotic flows.

  9. Intelligent Information Retrieval Using Rough Set Approximations.

    ERIC Educational Resources Information Center

    Srinivasan, Padmini

    1989-01-01

    Describes rough sets theory and discusses the advantages it offers for information retrieval, including the implicit inclusion of Boolean logic, term weighting, ranked retrieval output, and relevance feedback. Rough set formalism is compared to Boolean, vector, and fuzzy models of information retrieval and a small scale evaluation of rough sets is…

  10. Edge wave visualization

    NASA Technical Reports Server (NTRS)

    Dominek, Allen K.; Nguyen, Truong X.

    1991-01-01

    Scattering mechanisms that involve edge waves are addressed. The behavior of edge waves and their interaction with flat, perfectly conducting plates are depicted in the time domain through a visualization of surface currents that flow on the surface, as an incident Gaussian pulse of energy washes over the surface. Viewing these surface currents allows a very clear physical interpretation and appreciation of the scattering process.

  11. The comparison between modeling of edge localized modes with a current relaxation model and experiment on EAST

    NASA Astrophysics Data System (ADS)

    Cai, J. Q.; Liang, Y.; Pearson, J.; Zhang, T.; Zang, Q.; Wu, M. Q.; Huang, J.; Team1, EAST

    2017-08-01

    The distinctions of edge localized mode (ELM) frequency distributions between moderate and high edge current density cases were observed on the experiment advanced superconducting tokamak. In this paper, a current relaxation model is applied to explain this new observation. It has been demonstrated that the ELM frequency is very sensitive to the edge current density and the edge safety factor by the model predictions. The results also show that, in the large edge current density case, the ELM frequency is subject to a single-peak distribution; while in the moderate edge current density case, the ELM frequency is subject to a roughly multi-peak distribution.

  12. Calibration of surface roughness standards

    NASA Astrophysics Data System (ADS)

    Salgado, José; Duta, Alexandru; Lewis, Andrew; Gunn, Dave; Bartolo Picotto, Gian; Borovsky, Jiri; Nanits, Mats-Maidu; Mudronja, Vedran; Castellanos, Carlos Colin; Kornbilt, Fernando; Renegar, Brian; Motta de Souza, Marcos

    2017-01-01

    The key comparison EURAMET.L-K8.2009 on roughness was carried out in the framework of a EURAMET project starting in 2009 and ending in 2011. It involved the participation of 14 National Metrology Institutes from Europe, North America, Central America, South America and Africa representing three regional metrology organisations. Four surface texture standards of different type were circulated and on each of the standards several roughness parameters according to the standard ISO 4287 had to be determined. 27 out of 171 individual results were not consistent with the reference value. After some corrective actions the number of inconsistent results could be reduced to 24, which correspond to about 14% of the total. In addition to the material standards, two soft-gauges were circulated, which allow to test the software of the instruments used in the comparison. The comparison results help to support the calibraton and measurement capabilities (CMCs) of the laboratories involved in the CIPM MRA. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  13. Sliding mean edge estimation. [in digital image processing

    NASA Technical Reports Server (NTRS)

    Ford, G. E.

    1978-01-01

    A method for determining the locations of the major edges of objects in digital images is presented. The method is based on an algorithm utilizing maximum likelihood concepts. An image line-scan interval is processed to determine if an edge exists within the interval and its location. The proposed algorithm has demonstrated good results even in noisy images.

  14. Precision truing of diamond wheel with sharp edge

    NASA Astrophysics Data System (ADS)

    Ge, Cheng; Guo, Bing; Zhao, QIngliang; Chen, Bing; Wang, Jinhu

    2014-08-01

    Diamond wheel with sharp edge has small contour structures, which can lead to fast wear of wheel in the grinding process. Traditional truing methods are hard to apply to this kind of wheels. Therefore, as for the difficulty of precision truing of diamond wheel with sharp edge, the novel methods for resin and metal bonded diamond wheels with sharp edge are presented, respectively. In this experiment, a conditioning procedure with rare metal alloy block Ta was used to true the resin bonded diamond grinding wheel and in the same way Nb alloy block was utilized to complete rough truing of metal bonded diamond grinding wheel. Then a CNC truing technique with rotational green carbide (GC) truing stick was applied to precise truing of metal bonded diamond grinding wheel. Methods mentioned above were measured in order to evaluate the performance of truing. Geometric features of the wheel sharp edge were duplicated on the organic glass (PMMA) in order to measure and calculate the radius of the sharp edge. The edge radius of trued resin bonded wheel and metal bonded wheel is perceived as an important assessment. The experiments results revealed that the edge radius of 12.45μm for the resin bonded wheel and the edge radius of 30.17μm for the metal bonded wheel could be achieved.

  15. Attachment Line Blockage Models

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Photographs shows the attachment-line experiment model with fairing and fence for supersonic attachment-line experiments. The fairing is intended to eliminate the wing/fuselage juncture shock and align the flow for the streamlined fence. The streamlined fence traps the turbulent fuselage boundary layer to prevent turbulent contamination of the leading edge flow.

  16. The Edge supersonic transport

    NASA Technical Reports Server (NTRS)

    Agosta, Roxana; Bilbija, Dushan; Deutsch, Marc; Gallant, David; Rose, Don; Shreve, Gene; Smario, David; Suffredini, Brian

    1992-01-01

    As intercontinental business and tourism volumes continue their rapid expansion, the need to reduce travel times becomes increasingly acute. The Edge Supersonic Transport Aircraft is designed to meet this demand by the year 2015. With a maximum range of 5750 nm, a payload of 294 passengers and a cruising speed of M = 2.4, The Edge will cut current international flight durations in half, while maintaining competitive first class, business class, and economy class comfort levels. Moreover, this transport will render a minimal impact upon the environment, and will meet all Federal Aviation Administration Part 36, Stage III noise requirements. The cornerstone of The Edge's superior flight performance is its aerodynamically efficient, dual-configuration design incorporating variable-geometry wingtips. This arrangement combines the benefits of a high aspect ratio wing at takeoff and low cruising speeds with the high performance of an arrow-wing in supersonic cruise. And while the structural weight concerns relating to swinging wingtips are substantial, The Edge looks to ever-advancing material technologies to further increase its viability. Heeding well the lessons of the past, The Edge design holds economic feasibility as its primary focus. Therefore, in addition to its inherently superior aerodynamic performance, The Edge uses a lightweight, largely windowless configuration, relying on a synthetic vision system for outside viewing by both pilot and passengers. Additionally, a fly-by-light flight control system is incorporated to address aircraft supersonic cruise instability. The Edge will be produced at an estimated volume of 400 aircraft and will be offered to airlines in 2015 at $167 million per transport (1992 dollars).

  17. Subpatch roughness in earthquake rupture investigations

    NASA Astrophysics Data System (ADS)

    Zielke, O.; Mai, P. M.

    2016-03-01

    Fault geometric complexities exhibit fractal characteristics over a wide range of spatial scales (<µm to > km) and strongly affect the rupture process at corresponding scales. Numerical rupture simulations provide a framework to quantitatively investigate the relationship between a fault's roughness and its seismic characteristics. Fault discretization, however, introduces an artificial lower limit to roughness. Individual fault patches are planar and subpatch roughness—roughness at spatial scales below fault patch size—is not incorporated. Does negligence of subpatch roughness measurably affect the outcome of earthquake rupture simulations? We approach this question with a numerical parameter space investigation and demonstrate that subpatch roughness significantly modifies the slip-strain relationship—a fundamental aspect of dislocation theory. Faults with subpatch roughness induce less strain than their planar-fault equivalents at distances beyond the length of a slipping fault. We further provide regression functions that characterize the stochastic effect subpatch roughness.

  18. Edge-dependent selection rules in magic triangular graphene flakes

    NASA Astrophysics Data System (ADS)

    Akola, J.; Heiskanen, H. P.; Manninen, M.

    2008-05-01

    The electronic shell and supershell structure of triangular graphene quantum dots has been studied using density functional and tight-binding methods. The density functional calculations demonstrate that the electronic structure close to the Fermi energy is correctly described with a simple tight-binding model, where only the pz orbitals perpendicular to the graphene layer are included. The results show that (i) both at the bottom and at the top of the pz band, a supershell structure similar to that of free electrons confined in a triangular cavity is seen, (ii) close to the Fermi level, the shell structure is that of free massless particles, (iii) triangles with armchair edges show an additional sequence of levels (“ghost states”) absent for triangles with zigzag edges while the latter exhibit edge states, and (iv) the observed shell structure is rather insensitive to the edge roughness.

  19. Surface roughness analysis of hardened steel after high-speed milling.

    PubMed

    Twardowski, Paweł; Wojciechowski, Szymon; Wieczorowski, Michał; Mathia, Thomas

    2011-01-01

    The work refers to analysis of various factors affecting surface roughness after end milling of hardened steel in high-speed milling (HSM) conditions. Investigations of milling parameters (cutting speed v(c) , axial depth of cut a(p) ) and the process dynamics that influence machined surface roughness were presented, and a surface roughness model, including cutter displacements, was elaborated. The work also involved analysis of surface profile charts from the point of view of vibrations and cutting force components. The research showed that theoretic surface roughness resulting from the kinematic-geometric projection of cutting edge in the workpiece is significantly different from the reality. The dominant factor in the research was not feed per tooth f(z) (according to the theoretical model) but dynamical phenomena and feed per revolution f.

  20. Evaporation of Droplets on Superhydrophobic Surfaces: Surface Roughness and Small Droplet Size Effects

    NASA Astrophysics Data System (ADS)

    Chen, Xuemei; Ma, Ruiyuan; Li, Jintao; Hao, Chonglei; Guo, Wei; Luk, B. L.; Li, Shuai Cheng; Yao, Shuhuai; Wang, Zuankai

    2012-09-01

    Evaporation of a sessile droplet is a complex, nonequilibrium phenomenon. Although evaporating droplets upon superhydrophobic surfaces have been known to exhibit distinctive evaporation modes such as a constant contact line (CCL), a constant contact angle (CCA), or both, our fundamental understanding of the effects of surface roughness on the wetting transition remains elusive. We show that the onset time for the CCL-CCA transition and the critical base size at the Cassie-Wenzel transition exhibit remarkable dependence on the surface roughness. Through global interfacial energy analysis we reveal that, when the size of the evaporating droplet becomes comparable to the surface roughness, the line tension at the triple line becomes important in the prediction of the critical base size. Last, we show that both the CCL evaporation mode and the Cassie-Wenzel transition can be effectively inhibited by engineering a surface with hierarchical roughness.

  1. Evaporation of droplets on superhydrophobic surfaces: surface roughness and small droplet size effects.

    PubMed

    Chen, Xuemei; Ma, Ruiyuan; Li, Jintao; Hao, Chonglei; Guo, Wei; Luk, B L; Li, Shuai Cheng; Yao, Shuhuai; Wang, Zuankai

    2012-09-14

    Evaporation of a sessile droplet is a complex, nonequilibrium phenomenon. Although evaporating droplets upon superhydrophobic surfaces have been known to exhibit distinctive evaporation modes such as a constant contact line (CCL), a constant contact angle (CCA), or both, our fundamental understanding of the effects of surface roughness on the wetting transition remains elusive. We show that the onset time for the CCL-CCA transition and the critical base size at the Cassie-Wenzel transition exhibit remarkable dependence on the surface roughness. Through global interfacial energy analysis we reveal that, when the size of the evaporating droplet becomes comparable to the surface roughness, the line tension at the triple line becomes important in the prediction of the critical base size. Last, we show that both the CCL evaporation mode and the Cassie-Wenzel transition can be effectively inhibited by engineering a surface with hierarchical roughness.

  2. Adaptable edge quality metric

    NASA Astrophysics Data System (ADS)

    Strickland, Robin N.; Chang, Dunkai K.

    1990-09-01

    A new quality metric for evaluating edges detected by digital image processing algorithms is presented. The metric is a weighted sum of measures of edge continuity smoothness thinness localization detection and noisiness. Through a training process we can design weights which optimize the metric for different users and applications. We have used the metric to compare the results of ten edge detectors when applied to edges degraded by varying degrees of blur and varying degrees and types of noise. As expected the more optimum Difference-of-Gaussians (DOG) and Haralick methods outperform the simpler gradient detectors. At high signal-to-noise (SNR) ratios Haralick''s method is the best choice although it exhibits a sudden drop in performance at lower SNRs. The DOG filter''s performance degrades almost linearly with SNR and maintains a reasonably high level at lower SNRs. The same relative performances are observed as blur is varied. For most of the detectors tested performance drops with increasing noise correlation. Noise correlated in the same direction as the edge is the most destructive of the noise types tested.

  3. Defects detection for rough magnetic tiles surface based on light sectioning

    NASA Astrophysics Data System (ADS)

    Wang, Yuwei; Tao, Jiayuan; Chen, Xiangcheng; Wang, Keyi

    2016-09-01

    Magnetic tile as a kind of product of mass production and wide application in electronic motors, and defects detection is a major issue in its production line. In this paper, a machine vision method based on black-stripe projection is presented to deal with this issue. Because of magnetic tile surface with black colors, rough structure and complex grinding textures, we abandon intensity imaging and resort to light sectioning methods which provides more reliable and abundant surface information. In order to suppress the speckle diffraction effect caused by laser light source, we used the light-emitting diode (LED) with incoherent characteristics. The black-stripe images were captured by a high-speed camera. A fast algorithm was developed to extract and compare both edges of the black-stripe, which could detect defects and eliminate the effects of vibrations. The experimental results show that the simple and fast processing method proposed in this paper can detect the structural defects such as micro pits and micro cracks.

  4. Elastic guided waves in plates with surface roughness. II. Experiments

    SciTech Connect

    Lobkis, O.I.; Chimenti, D.E.

    1997-07-01

    In this artice are reported fundamental experimental measurements on guided waves in plates with surface roughness; the experimental data are critically compared to theoretical calculations presented in Part I. All experiments, in either immersion or contact coupling mode, are modeled by the theory developed in I that exploits the phase-screen approximation. In this theory the effect of the rough surface on the received signal, on a local scale, is assumed to be restricted to the signal phase. The comparisons between experiment and predictions show good agreement in most regimes, despite the rather simplifying approximations contained in the calculation. The model is shown to fail only when the guided wave vector is close to a branch point, that is when the guided wave phase velocity approaches the compressional or shear wavespeeds of the plate. Near these values the internal partial waves comprising the guided wave strike the surfaces at grazing incidence or are evanescent, and a simple phase-screen model cannot account for this behavior. Elsewhere in the guided wave spectrum, agreement is quite good. Of practical significance is the finding that the rough-surface damping contrast can be maximized by configuring the experimental conditions to measure just below and well above the compressional critical angle. Aluminum samples, prepared by indenting or sandblasting and independently profiled to determine rms roughness, are measured in immersion and in contact transduction, the latter with wedge couplers and line sources. The influence of the roughness in immersion experiments is strongly affected by whether the upper or lower plate surface is rough, but only in the interaction zone between specular and nonspecular reflection components. {copyright} {ital 1997 Acoustical Society of America.}

  5. Feather roughness reduces flow separation during low Reynolds number glides of swifts.

    PubMed

    van Bokhorst, Evelien; de Kat, Roeland; Elsinga, Gerrit E; Lentink, David

    2015-10-01

    Swifts are aerodynamically sophisticated birds with a small arm and large hand wing that provides them with exquisite control over their glide performance. However, their hand wings have a seemingly unsophisticated surface roughness that is poised to disturb flow. This roughness of about 2% chord length is formed by the valleys and ridges of overlapping primary feathers with thick protruding rachides, which make the wing stiffer. An earlier flow study of laminar-turbulent boundary layer transition over prepared swift wings suggested that swifts can attain laminar flow at a low angle of attack. In contrast, aerodynamic design theory suggests that airfoils must be extremely smooth to attain such laminar flow. In hummingbirds, which have similarly rough wings, flow measurements on a 3D printed model suggest that the flow separates at the leading edge and becomes turbulent well above the rachis bumps in a detached shear layer. The aerodynamic function of wing roughness in small birds is, therefore, not fully understood. Here, we performed particle image velocimetry and force measurements to compare smooth versus rough 3D-printed models of the swift hand wing. The high-resolution boundary layer measurements show that the flow over rough wings is indeed laminar at a low angle of attack and a low Reynolds number, but becomes turbulent at higher values. In contrast, the boundary layer over the smooth wing forms open laminar separation bubbles that extend beyond the trailing edge. The boundary layer dynamics of the smooth surface varies non-linearly as a function of angle of attack and Reynolds number, whereas the rough surface boasts more consistent turbulent boundary layer dynamics. Comparison of the corresponding drag values, lift values and glide ratios suggests, however, that glide performance is equivalent. The increased structural performance, boundary layer robustness and equivalent aerodynamic performance of rough wings might have provided small (proto) birds with

  6. Smooth and Rough Biotypes of Arcanobacterium haemolyticum Can Be Genetically Distinguished at the Arcanolysin Locus

    PubMed Central

    Ruther, Haley S.; Phillips, Kalyn; Ross, Dolores; Crawford, Alyssa; Weidner, M. Payton; Sammra, Osama; Lämmler, Christoph; McGee, David J.

    2015-01-01

    Arcanobacterium haemolyticum is a Gram-positive, β-hemolytic emerging human pathogen that is classified into smooth or rough biotypes. This bacterial species is also a rare pathogen of animals. Smooth biotypes possess smooth colony edges, are moderate to strong in β-hemolysis, and predominately cause wound infections. In contrast, rough biotypes possess rough and irregular colony edges, have weak to no β-hemolytic activity, and predominately cause pharyngitis. Using horse erythrocytes we confirmed that smooth isolates are generally more hemolytic than rough isolates. A hemolysin from A. haemolyticum, arcanolysin (aln/ALN), was recently discovered and is a member of the cholesterol-dependent cytolysin (CDC) family. PCR amplification of aln from all 36 smooth A. haemolyticum isolates yielded the expected 2.0 kb product. While 21 rough isolates yielded the 2.0 kb product, 16 isolates had a 3.2 kb product. The extra 1.2 kb segment was 99% identical to IS911 (insertion sequence) from Corynebacterium diphtheriae. PCR amplification and sequence analysis of the upstream region of aln revealed ~40 nucleotide polymorphisms among 73 clinical isolates from Finland, Denmark, Germany and United States (Nebraska). Remarkably, multi-sequence alignments of the aln upstream region demonstrated that ~90% of the isolates phylogenetically clustered as either smooths or roughs. Differential restriction enzyme analysis of the aln upstream region also demonstrated that the aln upstream region of most (~75%) smooth isolates was cleaved with ClaI while this region in most (~86%) rough isolates was cleaved with XcmI. We conclude that the aln upstream region can be used to genetically distinguish between smooth and rough biotypes of this important emerging pathogen. PMID:26382754

  7. Smooth and Rough Biotypes of Arcanobacterium haemolyticum Can Be Genetically Distinguished at the Arcanolysin Locus.

    PubMed

    Ruther, Haley S; Phillips, Kalyn; Ross, Dolores; Crawford, Alyssa; Weidner, M Payton; Sammra, Osama; Lämmler, Christoph; McGee, David J

    2015-01-01

    Arcanobacterium haemolyticum is a Gram-positive, β-hemolytic emerging human pathogen that is classified into smooth or rough biotypes. This bacterial species is also a rare pathogen of animals. Smooth biotypes possess smooth colony edges, are moderate to strong in β-hemolysis, and predominately cause wound infections. In contrast, rough biotypes possess rough and irregular colony edges, have weak to no β-hemolytic activity, and predominately cause pharyngitis. Using horse erythrocytes we confirmed that smooth isolates are generally more hemolytic than rough isolates. A hemolysin from A. haemolyticum, arcanolysin (aln/ALN), was recently discovered and is a member of the cholesterol-dependent cytolysin (CDC) family. PCR amplification of aln from all 36 smooth A. haemolyticum isolates yielded the expected 2.0 kb product. While 21 rough isolates yielded the 2.0 kb product, 16 isolates had a 3.2 kb product. The extra 1.2 kb segment was 99% identical to IS911 (insertion sequence) from Corynebacterium diphtheriae. PCR amplification and sequence analysis of the upstream region of aln revealed ~40 nucleotide polymorphisms among 73 clinical isolates from Finland, Denmark, Germany and United States (Nebraska). Remarkably, multi-sequence alignments of the aln upstream region demonstrated that ~90% of the isolates phylogenetically clustered as either smooths or roughs. Differential restriction enzyme analysis of the aln upstream region also demonstrated that the aln upstream region of most (~75%) smooth isolates was cleaved with ClaI while this region in most (~86%) rough isolates was cleaved with XcmI. We conclude that the aln upstream region can be used to genetically distinguish between smooth and rough biotypes of this important emerging pathogen.

  8. a Fast and Robust Algorithm for Road Edges Extraction from LIDAR Data

    NASA Astrophysics Data System (ADS)

    Qiu, Kaijin; Sun, Kai; Ding, Kou; Shu, Zhen

    2016-06-01

    Fast mapping of roads plays an important role in many geospatial applications, such as infrastructure planning, traffic monitoring, and driver assistance. How to extract various road edges fast and robustly is a challenging task. In this paper, we present a fast and robust algorithm for the automatic road edges extraction from terrestrial mobile LiDAR data. The algorithm is based on a key observation: most roads around edges have difference in elevation and road edges with pavement are seen in two different planes. In our algorithm, we firstly extract a rough plane based on RANSAC algorithm, and then multiple refined planes which only contains pavement are extracted from the rough plane. The road edges are extracted based on these refined planes. In practice, there is a serious problem that the rough and refined planes usually extracted badly due to rough roads and different density of point cloud. To eliminate the influence of rough roads, the technology which is similar with the difference of DSM (digital surface model) and DTM (digital terrain model) is used, and we also propose a method which adjust the point clouds to a similar density to eliminate the influence of different density. Experiments show the validities of the proposed method with multiple datasets (e.g. urban road, highway, and some rural road). We use the same parameters through the experiments and our algorithm can achieve real-time processing speeds.

  9. High Speed Edge Detection

    NASA Technical Reports Server (NTRS)

    Prokop, Norman F (Inventor)

    2015-01-01

    Analog circuits for detecting edges in pixel arrays are disclosed. A comparator may be configured to receive an all pass signal and a low pass signal for a pixel intensity in an array of pixels. A latch may be configured to receive a counter signal and a latching signal from the comparator. The comparator may be configured to send the latching signal to the latch when the all pass signal is below the low pass signal minus an offset. The latch may be configured to hold a last negative edge location when the latching signal is received from the comparator.

  10. High Speed Edge Detection

    NASA Technical Reports Server (NTRS)

    Prokop, Norman F (Inventor)

    2016-01-01

    Analog circuits for detecting edges in pixel arrays are disclosed. A comparator may be configured to receive an all pass signal and a low pass signal for a pixel intensity in an array of pixels. A latch may be configured to receive a counter signal and a latching signal from the comparator. The comparator may be configured to send the latching signal to the latch when the all pass signal is below the low pass signal minus an offset. The latch may be configured to hold a last negative edge location when the latching signal is received from the comparator.

  11. Influence of pitch, twist, and taper on a blade`s performance loss due to roughness

    SciTech Connect

    Tangler, J.L.

    1996-12-31

    The purpose of this study was to determine the influence of blade geometric parameters such as pitch, twist, and taper on a blade`s sensitivity to leading edge roughness. The approach began with an evaluation of available test data of performance degradation due to roughness effects for several rotors. In addition to airfoil geometry, this evaluation suggested that a rotor`s sensitivity to roughness was also influenced by the blade geometric parameters. Parametric studies were conducted using the PROP computer code with wind-tunnel airfoil characteristics for smooth and rough surface conditions to quantify the performance loss due to roughness for tapered and twisted blades relative to a constant-chord, non-twisted blade at several blade pitch angles. The results indicate that a constant-chord, non-twisted blade pitched toward stall will have the greatest losses due to roughness. The use of twist, taper, and positive blade pitch angles all help reduce the angle-of-attack distribution along the blade for a given wind speed and the associated performance degradation due to roughness. 8 refs., 6 figs.

  12. Effect of nano- and micro-roughness on adhesion of bioinspired micropatterned surfaces.

    PubMed

    Cañas, Natalia; Kamperman, Marleen; Völker, Benjamin; Kroner, Elmar; McMeeking, Robert M; Arzt, Eduard

    2012-01-01

    In this work, the adhesion of biomimetic polydimethylsiloxane (PDMS) pillar arrays with mushroom-shaped tips was studied on nano- and micro-rough surfaces and compared to unpatterned controls. The adhesion strength on nano-rough surfaces invariably decreased with increasing roughness, but pillar arrays retained higher adhesion strengths than unpatterned controls in all cases. The results were analyzed with a model that focuses on the effect on adhesion of depressions in a rough surface. The model fits the data very well, suggesting that the pull-off strength for patterned PDMS is controlled by the deepest dimple-like feature on the rough surface. The lower pull-off strength for unpatterned PDMS may be explained by the initiation of the pull-off process at the edge of the probe, where significant stress concentrates. With micro-rough surfaces, pillar arrays showed maximum adhesion with a certain intermediate roughness, while unpatterned controls did not show any measurable adhesion. This effect can be explained by the inability of micropatterned surfaces to conform to very fine and very large surface asperities.

  13. A Quantitative Investigation of Surface Roughness Effects on Airfoil Boundary Layer Transition Using Infrared Thermography

    NASA Astrophysics Data System (ADS)

    Beeby, Todd Daniel

    An investigation of the impact of subcritical leading edge distributed roughness elements on airfoil boundary layer transition location has been undertaken using infrared thermography. In particular, a quantitative approach to boundary layer transition location detection using a differential energy balance method was implemented using a heating pad to produce constant heat flux. This was performed on a S809 airfoil model at Re c = 0.75 and 1.0 x 106, using roughness elements of height k/c = 3.75, 4.25 and 5.00 x 10 --4, pattern densities of 2 to 10 %, and roughness locations of 1 to 6 % chord. Turbulator tape of height k/c = 6.67 x 10--4 was also examined. Results indicate significant impact on transition for all roughness cases, and a more pronounced influence of roughness density as compared to roughness element height. The phenomenon of early laminar bubble collapse was also found to occur for some roughness configurations. The quantitative method used was found to be an effective means for automated transition location determination.

  14. Experimental and model-based study of the robustness of line-edgeroughness metric extraction in the presence of noise

    SciTech Connect

    Naulleau, Patrick P.; Cain, Jason P.

    2007-06-01

    As critical dimensions shrink, line edge and width roughness (LER and LWR) become of increasing concern. Crucial to the goal of reducing LER is its accurate characterization. LER has traditionally been represented as a single rms value. More recently the use of power spectral density (PSD), height-height correlation (HHCF), and {sigma} versus length plots has been proposed in order to extract the additional spatial descriptors of correlation length and roughness exponent. Here we perform a modeling-based noise-sensitivity study on the extraction of spatial descriptors from line-edge data as well as an experimental study of the robustness of these various descriptors using a large dataset of recent extreme-ultraviolet exposure data. The results show that in the presence of noise and in the large dataset limit, the PSD method provides higher accuracy in the extraction of the roughness exponent, whereas the HHCF method provides higher accuracy for the correlation length. On the other hand, when considering precision, the HHCF method is superior for both metrics.

  15. Controllable edge feature sharpening for dental applications.

    PubMed

    Fan, Ran; Jin, Xiaogang

    2014-01-01

    This paper presents a new approach to sharpen blurred edge features in scanned tooth preparation surfaces generated by structured-light scanners. It aims to efficiently enhance the edge features so that the embedded feature lines can be easily identified in dental CAD systems, and to avoid unnatural oversharpening geometry. We first separate the feature regions using graph-cut segmentation, which does not require a user-defined threshold. Then, we filter the face normal vectors to propagate the geometry from the smooth region to the feature region. In order to control the degree of the sharpness, we propose a feature distance measure which is based on normal tensor voting. Finally, the vertex positions are updated according to the modified face normal vectors. We have applied the approach to scanned tooth preparation models. The results show that the blurred edge features are enhanced without unnatural oversharpening geometry.

  16. Edge effects in composites by moire interferometry

    NASA Technical Reports Server (NTRS)

    Czarnek, R.; Post, D.; Herakovich, C.

    1983-01-01

    The very high sensitivity of moire interferometry has permitted the present edge effect experiments to be conducted at a low average stress and strain level, assuring linear and elastic behavior in the composite material samples tested. Sensitivity corresponding to 2450 line/mm moire was achieved with a 0.408 micron/fringe. Simultaneous observations of the specimen face and edge displacement fields showed good fringe definition despite the 1-mm thickness of the specimens and the high gradients, and it is noted that the use of a carrier pattern and optical filtering was effective in even these conditions. Edge effects and dramatic displacement gradients were confirmed in angle-ply composite laminates.

  17. Edge effects in composites by moire interferometry

    NASA Technical Reports Server (NTRS)

    Czarnek, R.; Post, D.; Herakovich, C.

    1983-01-01

    The very high sensitivity of moire interferometry has permitted the present edge effect experiments to be conducted at a low average stress and strain level, assuring linear and elastic behavior in the composite material samples tested. Sensitivity corresponding to 2450 line/mm moire was achieved with a 0.408 micron/fringe. Simultaneous observations of the specimen face and edge displacement fields showed good fringe definition despite the 1-mm thickness of the specimens and the high gradients, and it is noted that the use of a carrier pattern and optical filtering was effective in even these conditions. Edge effects and dramatic displacement gradients were confirmed in angle-ply composite laminates.

  18. How visual edge features influence cuttlefish camouflage patterning.

    PubMed

    Chiao, Chuan-Chin; Ulmer, Kimberly M; Siemann, Liese A; Buresch, Kendra C; Chubb, Charles; Hanlon, Roger T

    2013-05-03

    Rapid adaptive camouflage is the primary defense of soft-bodied cuttlefish. Previous studies have shown that cuttlefish body patterns are strongly influenced by visual edges in the substrate. The aim of the present study was to examine how cuttlefish body patterning is differentially controlled by various aspects of edges, including contrast polarity, contrast strength, and the presence or absence of "line terminators" introduced into a pattern when continuous edges are fragmented. Spatially high- and low-pass filtered white or black disks, as well as isolated, continuous and fragmented edges varying in contrast, were used to assess activation of cuttlefish skin components. Although disks of both contrast polarities evoked relatively weak disruptive body patterns, black disks activated different skin components than white disks, and high-frequency information alone sufficed to drive the responses to white disks whereas high- and low-frequency information were both required to drive responses to black disks. Strikingly, high-contrast edge fragments evoked substantially stronger body pattern responses than low-contrast edge fragments, whereas the body pattern responses evoked by high-contrast continuous edges were no stronger than those produced by low-contrast edges. This suggests that line terminators vs. continuous edges influence expression of disruptive body pattern components via different mechanisms that are controlled by contrast in different ways. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Equilibrium contact angles of liquid droplets on ideal rough solids.

    PubMed

    Kang, Hie Chan; Jacobi, Anthony M

    2011-12-20

    This work proposes a theoretical model for predicting the apparent equilibrium contact angle of a liquid on an ideal rough surface that is homogeneous and has a negligible body force, line tension, or contact angle hysteresis between solid and liquid. The model is derived from the conservation equations and the free-energy minimization theory for the changes of state of liquid droplets. The work of adhesion is expressed as the contact angles in the wetting process of the liquid droplets. Equilibrium contact angles of liquid droplets for rough surfaces are expressed as functions of the area ratios for the solid, liquid, and surrounding gas and the roughness ratio and wetting ratio of the liquid on the solid for the partially and fully wet states. It is found that the ideal critical angle for accentuating the contact angles by the surface roughness is 48°. The present model is compared with existing experimental data and the classical Wenzel and Cassie-Baxter models and agrees with most of the experimental data for various surfaces and liquids better than does the Wenzel model and accounts for trends that the Wenzel model cannot explain.

  20. Surface roughness stabilizes the clustering of self-propelled triangles

    NASA Astrophysics Data System (ADS)

    Ilse, Sven Erik; Holm, Christian; de Graaf, Joost

    2016-10-01

    Self-propelled particles can spontaneously form dense phases from a dilute suspension in a process referred to as motility-induced phase separation. The properties of the out-of-equilibrium structures that are formed are governed by the specifics of the particle interactions and the strength of the activity. Thus far, most studies into the formation of these structures have focused on spherical colloids, dumbbells, and rod-like particles endowed with various interaction potentials. Only a few studies have examined the collective behavior of more complex particle shapes. Here, we increase the geometric complexity and use molecular dynamics simulations to consider the structures formed by triangular self-propelled particles with surface roughness. These triangles either move towards their apex or towards their base, i.e., they possess a polarity. We find that apex-directed triangles cluster more readily, more stably, and have a smoother cluster interface than their base-directed counterparts. A difference between the two polarities is in line with the results of Wensink et al. [Phys. Rev. E 89, 010302 (2014)]; however, we obtain the reversed result when it comes to clustering, namely, that apex-directed triangles cluster more successfully. We further show that reducing the surface roughness negatively impacts the stability of the base-directed structures, suggesting that their formation is in large part due to surface roughness. Our results lay a solid foundation for future experimental and computational studies into the effect of roughness on the collective dynamics of swimmers.

  1. Swords with Blunt Edges

    ERIC Educational Resources Information Center

    Popham, W. James

    2004-01-01

    Many U.S. educators now wonder whether they're teachers or targets. This mentality stems from the specter of their school being sanctioned for failing the state accountability tests mandated under No Child Left Behind (NCLB). According to this author, most of those tests are like blunt-edged swords: They function badly in two directions. While…

  2. The Inner Urban Edge

    ERIC Educational Resources Information Center

    Ferebee, Ann; Carpenter, Edward K.

    1974-01-01

    In this article, renewal of the inner urban edge is discussed. Norfolk (Virginia) is attempting to blur the difference between old and new neighbor hoods through zoning and architectural controls. Cincinnati (Ohio) is developing an environmentally sound hillside design. Reading (Pennsylvania) is utilizing old railyards for greenbelts of hiking and…

  3. Turbulent Flow over Rough Turbine Airfoils.

    DTIC Science & Technology

    1985-08-01

    SUBJECT TERMS (Continue on reverse if necessary and identify by block number) FIELD GROUP SUB. GR. Turbine blades ’ vanes ; surface roughness...turbulent boundary layer over rough turbine vanes or blades is developed. A new formulation of the mixing length model, expressed in the velocity-space...A-163 005 TURBULENT FLOW OVER ROUGH TURBINE AIRFOILS (U) OHIO 1/ STATE UNIV RESEARCH FOUNDATION COLUMBUS L S HAN AUG B5 OSURF-76357/?i4467 AFWL-TR-95

  4. Study on surface roughness evolvement of Nd-doped phosphate glass after IBF

    NASA Astrophysics Data System (ADS)

    Li, Furen; Xie, Xuhui; Zhou, Lin; Tie, Guipeng; Hu, Hao

    2016-10-01

    Nd doped phosphate glass is widely used as gain media in high power laser system. It is traditionally polished with the annular polishing technology. The edge effect is inevitable in annular polishing process and it results in the low manufacturing efficiency. Ion Beam Figuring (IBF) is a highly deterministic, non-contact method for the ultra-precision optics fabrication. So the edge effect is avoided. Nanometer and sub-nanometer precision is realizable in IBF. In this paper, Nd doped phosphate glass was polished with IBF, and the evolvement of surface roughness was emphasized. The roughness of surface polished with ion beam at normal and oblique incidence was researched. The oblique incident angle was 45°. The surface roughness was measured with the white light interferometer. No evident change was observed. This means that the pre-finish roughness can be preserved in IBF. The results denote that IBF is a feasible method to correct the contour errors of Nd doped phosphate glass, and the roughness will not be coarsened.

  5. Simplified Approach to Predicting Rough Surface Transition

    NASA Technical Reports Server (NTRS)

    Boyle, Robert J.; Stripf, Matthias

    2009-01-01

    Turbine vane heat transfer predictions are given for smooth and rough vanes where the experimental data show transition moving forward on the vane as the surface roughness physical height increases. Consiste nt with smooth vane heat transfer, the transition moves forward for a fixed roughness height as the Reynolds number increases. Comparison s are presented with published experimental data. Some of the data ar e for a regular roughness geometry with a range of roughness heights, Reynolds numbers, and inlet turbulence intensities. The approach ta ken in this analysis is to treat the roughness in a statistical sense , consistent with what would be obtained from blades measured after e xposure to actual engine environments. An approach is given to determ ine the equivalent sand grain roughness from the statistics of the re gular geometry. This approach is guided by the experimental data. A roughness transition criterion is developed, and comparisons are made with experimental data over the entire range of experimental test co nditions. Additional comparisons are made with experimental heat tran sfer data, where the roughness geometries are both regular as well a s statistical. Using the developed analysis, heat transfer calculatio ns are presented for the second stage vane of a high pressure turbine at hypothetical engine conditions.

  6. Simplified Approach to Predicting Rough Surface Transition

    NASA Technical Reports Server (NTRS)

    Boyle, R. J.; Stripf, M.

    2009-01-01

    Turbine vane heat transfer predictions are given for smooth and rough vanes where the experimental data show transition moving forward on the vane as the surface roughness physical height increases. Consistent with smooth vane heat transfer, the transition moves forward for a fixed roughness height as the Reynolds number increases. Comparisons are presented with published experimental data. Some of the data are for a regular roughness geometry with a range of roughness heights, Reynolds numbers, and inlet turbulence intensities. The approach taken in this analysis is to treat the roughness in a statistical sense, consistent with what would be obtained from blades measured after exposure to actual engine environments. An approach is given to determine the equivalent sand grain roughness from the statistics of the regular geometry. This approach is guided by the experimental data. A roughness transition criterion is developed, and comparisons are made with experimental data over the entire range of experimental test conditions. Additional comparisons are made with experimental heat transfer data, where the roughness geometries are both regular and statistical. Using the developed analysis, heat transfer calculations are presented for the second stage vane of a high pressure turbine at hypothetical engine conditions.

  7. Simplified Approach to Predicting Rough Surface Transition

    NASA Technical Reports Server (NTRS)

    Boyle, R. J.; Stripf, M.

    2009-01-01

    Turbine vane heat transfer predictions are given for smooth and rough vanes where the experimental data show transition moving forward on the vane as the surface roughness physical height increases. Consistent with smooth vane heat transfer, the transition moves forward for a fixed roughness height as the Reynolds number increases. Comparisons are presented with published experimental data. Some of the data are for a regular roughness geometry with a range of roughness heights, Reynolds numbers, and inlet turbulence intensities. The approach taken in this analysis is to treat the roughness in a statistical sense, consistent with what would be obtained from blades measured after exposure to actual engine environments. An approach is given to determine the equivalent sand grain roughness from the statistics of the regular geometry. This approach is guided by the experimental data. A roughness transition criterion is developed, and comparisons are made with experimental data over the entire range of experimental test conditions. Additional comparisons are made with experimental heat transfer data, where the roughness geometries are both regular and statistical. Using the developed analysis, heat transfer calculations are presented for the second stage vane of a high pressure turbine at hypothetical engine conditions.

  8. Rough set models of Physarum machines

    NASA Astrophysics Data System (ADS)

    Pancerz, Krzysztof; Schumann, Andrew

    2015-04-01

    In this paper, we consider transition system models of behaviour of Physarum machines in terms of rough set theory. A Physarum machine, a biological computing device implemented in the plasmodium of Physarum polycephalum (true slime mould), is a natural transition system. In the behaviour of Physarum machines, one can notice some ambiguity in Physarum motions that influences exact anticipation of states of machines in time. To model this ambiguity, we propose to use rough set models created over transition systems. Rough sets are an appropriate tool to deal with rough (ambiguous, imprecise) concepts in the universe of discourse.

  9. Atomic Scattering Factor of the ASTRO-H (Hitomi) SXT Reflector Around the Gold's L Edges

    NASA Technical Reports Server (NTRS)

    Kikuchi, Naomichi; Kurashima, Sho; Ishida, Manabu; Iizuka, Ryo; Maeda, Yoshitomo; Hayashi, Takayuki; Okajima, Takashi; Matsumoto, Hironori; Mitsubishi, Ikuyuki; Saji, Shigetaka

    2016-01-01

    The atomic scattering factor in the energy range of 11.2 - 15.4 keV for the ASTRO-H Soft X-ray Telescope (SXT) is reported. The large effective area of the SXT makes use of photon spectra above 10 keV viable, unlike most other X-ray satellites with total-reflection mirror optics. Presence of gold's L-edges in the energy band is a major issue, as it complicates the function of the effective area. In order to model the area, the reflectivity measurements in the 11.2 - 15.4 keV band with the energy pitch of 0.4 - 0.7 eV were made in the synchrotron beam-line Spring-8 BL01B1. We obtained atomic scattering factors f1 and f2 by the curve fitting to the reflectivities of our witness sample. The edges associated with the L-I, II, and III transitions are identified, of which the depths are found to be roughly 60 shallower than those expected from the Henkes atomic scattering factor.

  10. Effects of Airfoil Thickness and Maximum Lift Coefficient on Roughness Sensitivity: 1997--1998

    SciTech Connect

    Somers, D. M.

    2005-01-01

    A matrix of airfoils has been developed to determine the effects of airfoil thickness and the maximum lift to leading-edge roughness. The matrix consists of three natural-laminar-flow airfoils, the S901, S902, and S903, for wind turbine applications. The airfoils have been designed and analyzed theoretically and verified experimentally in the Pennsylvania State University low-speed, low-turbulence wind tunnel. The effect of roughness on the maximum life increases with increasing airfoil thickness and decreases slightly with increasing maximum lift. Comparisons of the theoretical and experimental results generally show good agreement.

  11. Superpixel edges for boundary detection

    SciTech Connect

    Moya, Mary M.; Koch, Mark W.

    2016-07-12

    Various embodiments presented herein relate to identifying one or more edges in a synthetic aperture radar (SAR) image comprising a plurality of superpixels. Superpixels sharing an edge (or boundary) can be identified and one or more properties of the shared superpixels can be compared to determine whether the superpixels form the same or two different features. Where the superpixels form the same feature the edge is identified as an internal edge. Where the superpixels form two different features, the edge is identified as an external edge. Based upon classification of the superpixels, the external edge can be further determined to form part of a roof, wall, etc. The superpixels can be formed from a speckle-reduced SAR image product formed from a registered stack of SAR images, which is further segmented into a plurality of superpixels. The edge identification process is applied to the SAR image comprising the superpixels and edges.

  12. A rough set approach for determining weights of decision makers in group decision making

    PubMed Central

    Yang, Qiang; Du, Ping-an; Wang, Yong; Liang, Bin

    2017-01-01

    This study aims to present a novel approach for determining the weights of decision makers (DMs) based on rough group decision in multiple attribute group decision-making (MAGDM) problems. First, we construct a rough group decision matrix from all DMs’ decision matrixes on the basis of rough set theory. After that, we derive a positive ideal solution (PIS) founded on the average matrix of rough group decision, and negative ideal solutions (NISs) founded on the lower and upper limit matrixes of rough group decision. Then, we obtain the weight of each group member and priority order of alternatives by using relative closeness method, which depends on the distances from each individual group member’ decision to the PIS and NISs. Through comparisons with existing methods and an on-line business manager selection example, the proposed method show that it can provide more insights into the subjectivity and vagueness of DMs’ evaluations and selections. PMID:28234974

  13. Optimum surface roughness prediction for titanium alloy by adopting response surface methodology

    NASA Astrophysics Data System (ADS)

    Yang, Aimin; Han, Yang; Pan, Yuhang; Xing, Hongwei; Li, Jinze

    Titanium alloy has been widely applied in industrial engineering products due to its advantages of great corrosion resistance and high specific strength. This paper investigated the processing parameters for finish turning of titanium alloy TC11. Firstly, a three-factor central composite design of experiment, considering the cutting speed, feed rate and depth of cut, are conducted in titanium alloy TC11 and the corresponding surface roughness are obtained. Then a mathematic model is constructed by the response surface methodology to fit the relationship between the process parameters and the surface roughness. The prediction accuracy was verified by the one-way ANOVA. Finally, the contour line of the surface roughness under different combination of process parameters are obtained and used for the optimum surface roughness prediction. Verification experimental results demonstrated that material removal rate (MRR) at the obtained optimum can be significantly improved without sacrificing the surface roughness.

  14. CdTe surface roughness by Raman spectroscopy using the 830 nm wavelength.

    PubMed

    Frausto-Reyes, C; Molina-Contreras, J Rafael; Medina-Gutiérrez, C; Calixto, Sergio

    2006-09-01

    A Raman spectroscopic study was performed to detect the surface roughness of a cadmium telluride (CdTe) wafer sample, using the 514.5, 632.8 and 830.0 nm excitations wavelengths. To verify the relation between the roughness and the structure of Raman spectra, in certain zones of the sample, we measured their roughness with an atomic force microscopy. It was found that, using the 830 nm wavelength there is a direct correspondence between the spectrum structure and the surface roughness. For the others wavelengths it was found, however, that there is not a clearly correspondence between them. Our results suggest that, using the excitation wavelength of 830 nm the Raman spectroscopy can be used as an on-line roughness monitor on the CdTe growth.

  15. A rough set approach for determining weights of decision makers in group decision making.

    PubMed

    Yang, Qiang; Du, Ping-An; Wang, Yong; Liang, Bin

    2017-01-01

    This study aims to present a novel approach for determining the weights of decision makers (DMs) based on rough group decision in multiple attribute group decision-making (MAGDM) problems. First, we construct a rough group decision matrix from all DMs' decision matrixes on the basis of rough set theory. After that, we derive a positive ideal solution (PIS) founded on the average matrix of rough group decision, and negative ideal solutions (NISs) founded on the lower and upper limit matrixes of rough group decision. Then, we obtain the weight of each group member and priority order of alternatives by using relative closeness method, which depends on the distances from each individual group member' decision to the PIS and NISs. Through comparisons with existing methods and an on-line business manager selection example, the proposed method show that it can provide more insights into the subjectivity and vagueness of DMs' evaluations and selections.

  16. Droplet spreading and absorption on rough, permeable substrates

    NASA Astrophysics Data System (ADS)

    Espin, Leonardo; Kumar, Satish

    2015-11-01

    Wetting of permeable substrates by liquids is an important phenomenon in many natural and industrial processes. Substrate heterogeneities may significantly alter liquid spreading and interface shapes, which in turn may alter liquid imbibition. A new lubrication-theory-based model for droplet spreading on permeable substrates that incorporates surface roughness is developed in this work. The substrate is assumed to be saturated with liquid, and the contact-line region is described by including a precursor film and disjoining pressure. A novel boundary condition for liquid imbibition is applied that eliminates the need for a droplet-thickness-dependent substrate permeability that has been employed in previous models. A nonlinear evolution equation describing droplet height as a function of time and the radial coordinate is derived and then numerically solved to characterize the influence of substrate permeability and roughness on axisymmetric droplet spreading. Because it incorporates surface roughness, the new model is able to describe the contact-line pinning that has been observed in experiments but not captured by previous models.

  17. Rock discontinuity surface roughness variation with scale

    NASA Astrophysics Data System (ADS)

    Bitenc, Maja; Kieffer, D. Scott; Khoshelham, Kourosh

    2017-04-01

    ABSTRACT: Rock discontinuity surface roughness refers to local departures of the discontinuity surface from planarity and is an important factor influencing the shear resistance. In practice, the Joint Roughness Coefficient (JRC) roughness parameter is commonly relied upon and input to a shear strength criterion such as developed by Barton and Choubey [1977]. The estimation of roughness by JRC is hindered firstly by the subjective nature of visually comparing the joint profile to the ten standard profiles. Secondly, when correlating the standard JRC values and other objective measures of roughness, the roughness idealization is limited to a 2D profile of 10 cm length. With the advance of measuring technologies that provide accurate and high resolution 3D data of surface topography on different scales, new 3D roughness parameters have been developed. A desirable parameter is one that describes rock surface geometry as well as the direction and scale dependency of roughness. In this research a 3D roughness parameter developed by Grasselli [2001] and adapted by Tatone and Grasselli [2009] is adopted. It characterizes surface topography as the cumulative distribution of local apparent inclination of asperities with respect to the shear strength (analysis) direction. Thus, the 3D roughness parameter describes the roughness amplitude and anisotropy (direction dependency), but does not capture the scale properties. In different studies the roughness scale-dependency has been attributed to data resolution or size of the surface joint (see a summary of researches in [Tatone and Grasselli, 2012]). Clearly, the lower resolution results in lower roughness. On the other hand, have the investigations of surface size effect produced conflicting results. While some studies have shown a decrease in roughness with increasing discontinuity size (negative scale effect), others have shown the existence of positive scale effects, or both positive and negative scale effects. We

  18. Shape of patch edges affects edge permeability for meadow voles.

    PubMed

    Nams, Vilis O

    2012-09-01

    Human development typically fragments natural habitats into patches, affecting population and metapopulation dynamics via changes in animal behavior. Emigration from one habitat patch to another has a large effect on population and metapopulation dynamics. One factor that affects emigration is permeability of patch edges. This study looks at the effects of edge shape (convex, concave, and straight) on edge permeability for meadow voles (Microtus pennsylvanicus).. I tested five hypotheses for responses of animal movement to patch shape: (1) neutral edge response; (2) edge attraction; (3) edge avoidance; (4) time-minimizing, in which an animal attempts to minimize the time spent in inhospitable matrix, and thus travels as far as possible in the patch before crossing the edge; and (5) protection, in which an animal attempts to maximize protection while in the inhospitable matrix by keeping the patch close by. These hypotheses were tested by an experimental manipulation of meadow vole habitats. A strip was mowed with different edge shapes through an old field, and vole response was measured by tracking plates. Voles crossed edges at concave treatments twice as often compared to convex and straight shapes. Hypotheses (2) and (5) were supported. Although edge attraction causes a passive effect of a decrease in edge-crossing at concavities, this effect was eclipsed by the active effect of voles choosing to cross at concavities. The results can be generalized to edge tortuosity in general. Conservation biologists should consider edge shapes when exploring the effects of habitat fragmentation on animal populations.

  19. Effect of sealer coating and storage methods on the surface roughness of soft liners.

    PubMed

    Usta Kutlu, Ilknur; Yanikoğlu, Nuran Dinckal; Kul, Esra; Duymuş, Zeynep Yesïl; Sağsöz, Nurdan Polat

    2016-03-01

    A soft lining is applied under a removable prosthesis for various reasons. The porosity of the lining material may increase colonization by microorganisms and cause tissue inflammation. The purpose of this in vitro study was to evaluate the effect of sealer coating on the surface roughness of soft lining materials under 4 different conditions. A total of 125 specimens were prepared. One high-temperature silicone-based soft lining material and 2 room-temperature-polymerized soft lining materials (1 silicone-based and 1 methacrylate-based) were used. Twenty-five specimens of each room-temperature soft lining material were coated with 2 layers of surface sealer. Additionally, 5 specimens of each material were stored in either distilled water, Coca-Cola, denture cleanser, saliva, or air. The surface roughness was measured at baseline and after 1, 7, 14, and 28 days. Surface roughness values were analyzed with repeated measures analysis of variance, and the Bonferroni multiple comparison test was performed using time-dependent groups and storage methods. In the time-dependent groups, methacrylate-based sealer-coated soft liners exhibited a significant increase in roughness (1.74-2.09 μm, P<.001), and silicone-based sealer-coated soft liners exhibited a decrease in roughness, but it was not significant (2.16-2.02 μm, P>.05). Therefore, the sealer coating was not effective in reducing surface roughness. Among the time-dependent storage methods, the denture cleanser exhibited an almost significant increase in roughness (1.83-1.99 μm, P=.054). Coca-Cola and artificial saliva did not show a significant difference (P>.05). However, a significant decrease in roughness was found with distilled water (P=.02) and air (P<.001). Statistically significant differences in surface roughness were found among the different types of soft liners. The sealer coating had no significant effect, and denture cleanser slightly increased the surface roughness. Contrary to expectations, the

  20. Experimental Measurement and CFD Model Development of Thick Wind Turbine Airfoils with Leading Edge Erosion

    NASA Astrophysics Data System (ADS)

    Maniaci, David C.; White, Edward B.; Wilcox, Benjamin; Langel, Christopher M.; van Dam, C. P.; Paquette, Joshua A.

    2016-09-01

    Leading edge erosion and roughness accumulation is an issue observed with great variability by wind plant operators, but with little understanding of the effect on wind turbine performance. In wind tunnels, airfoil models are typically tested with standard grit roughness and trip tape to simulate the effects of roughness and erosion observed in field operation, but there is a lack of established relation between field measurements and wind tunnel test conditions. A research collaboration between lab, academic, and industry partners has sought to establish a method to estimate the effect of erosion in wind turbine blades that correlates to roughness and erosion measured in the field. Measurements of roughness and erosion were taken off of operational utility wind turbine blades using a profilometer. The field measurements were statistically reproduced in the wind tunnel on representative tip and midspan airfoils. Simultaneously, a computational model was developed and calibrated to capture the effect of roughness and erosion on airfoil transition and performance characteristics. The results indicate that the effects of field roughness fall between clean airfoil performance and the effects of transition tape. Severe leading edge erosion can cause detrimental performance effects beyond standard roughness. The results also indicate that a heavily eroded wind turbine blade can reduce annual energy production by over 5% for a utility scale wind turbine.

  1. Effect of roughness on imaging and characterizing rough crack-like defect using ultrasonic arrays

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Drinkwater, B. W.; Wilcox, P. D.

    2012-05-01

    All naturally occurring crack-like defects in solid structures are rough to some degree, which can affect defect inspection and characterization. Based on the simulated array data for various rough cracks and the total focusing method imaging algorithm, the effect of roughness on defect imaging and characterization was discussed. The array data was simulated by using the forward model combining with scattering matrices for various rough cracks. The scattering matrix describes the scattering field of a scatterer from all possible incident and scattering directions. It is shown that roughness can be either beneficial or detrimental to the detectability of a crack-like defect, depending on the defect characteristics such as length, roughness, correlation length, orientation angle, and array inspection configuration. It is also shown that roughness can cause the underestimation of length of rough crack-like defects by using the image-based approach.

  2. Activating without Inhibiting: Left-Edge Boundary Tones and Syntactic Processing

    ERIC Educational Resources Information Center

    Roll, Mikael; Horne, Merle; Lindgren, Magnus

    2011-01-01

    Right-edge boundary tones have earlier been found to restrict syntactic processing by closing a clause for further integration of incoming words. The role of left-edge intonation, however, has received little attention to date. We show that Swedish left-edge boundary tones selectively facilitate the on-line processing of main clauses, the…

  3. Activating without Inhibiting: Left-Edge Boundary Tones and Syntactic Processing

    ERIC Educational Resources Information Center

    Roll, Mikael; Horne, Merle; Lindgren, Magnus

    2011-01-01

    Right-edge boundary tones have earlier been found to restrict syntactic processing by closing a clause for further integration of incoming words. The role of left-edge intonation, however, has received little attention to date. We show that Swedish left-edge boundary tones selectively facilitate the on-line processing of main clauses, the…

  4. Simulation of shotnoise induced side-wall roughness in electron lithography

    NASA Astrophysics Data System (ADS)

    Verduin, T.; Lokhorst, S. R.; Hagen, C. W.; Kruit, P.

    2016-03-01

    We have developed a fast three dimensional Monte-Carlo framework for the investigation of shotnoise induced side-wall roughness (SWR) formation. The calculation outline is demonstrated by an example for an exposure of a 100nm thick layer of negative tone resist (NTR) resist on top of an infinitely thick silicon substrate. We use our home built Monte-Carlo simulator for electron-matter interaction for the purpose of lithography. A pattern of an isolated line is written into the resist layer by scanning a beam with 20 keV electrons over an area of 32nm×1μm (width and length). During the exposure, we use a spot size of 20 nm, beam step size of 4nm and a Poisson distributed exposure dose of 80 μC/cm2, 60 μC/cm2 and 40 μC/cm2. During the exposure of the sample, we record the locations of the inelastic events within the resist layer. The distribution of released acids is determined under the simplified assumption that every inelastic event corresponds to a release. We now construct a three dimensional image of the (in)solubility of the resist layer within a cuboid of 128 nm(256px) wide, 800 nm(1024px) in length and 100 nm(128px) in height. It is obtained by summing the contribution of all acids to every voxel in the three dimensional image. We have used a three dimensional Gaussian with σx,y,z = rd =5nm for the diffusion of the acid. The boundary between exposed and unexposed resist is determined by a threshold. The resulting image of the (in)solubility is analyzed in different ways by considering slices and three dimensional views of the border. The average line edge roughness (LER) is obtained by calculating the standard deviation (one-sigma) of the left and right border from yz-slices. By considering all slices, ranging from the top of the resist layer to the bottom of the substrate, the average LER as a function of the depth from the top surface of the resist layer is obtained. Shotnoise effects are observed as we decrease the exposure dose. An increased effect

  5. Surface Roughness Metrology By Angular Distributions Of Scattered Light

    NASA Astrophysics Data System (ADS)

    Gilsinn, David E.; Vorburger, Theodore V.; Teague, E. Clayton; MeLay, Michael J.; Giauque, Charles; Scire, Fredric E.

    1985-09-01

    On-line industrial inspection of batch manufactured parts requires fast measurement techniques for surface finish quality. In order to develop the measurement basis for these techniques, a system has been built to determine surface roughness by measuring the angular distributions of scattered light. The system incorporates data gathered from the angular distribution instrument and traditional surface stylus instruments. These data are used both as input and as comparison data in order to test various mathematical models of optical scattering phenomena. The object is to develop a mathematical model that uses the angular distribution of scattered light to deduce surface roughness parameters such as Ra and surface wavelength. This paper describes the results of an experiment in which angular scattered data from surfaces with sinusoidal profiles was used to compute the surface R and wavelength. Stylus measurements of these parameters were made separately. A comparative table is given of the computed and measured values. Estimates of uncertainties are also given.

  6. Updated Model of Radar Backscatter for Rough Lunar Craters

    NASA Technical Reports Server (NTRS)

    Thompson, Thomas W.; Ustinov, Eugene A.

    2013-01-01

    We reexamined our radar scattering model for young, rough craters [1] based on unpublished data from the 1980's [2]. Our model for scattering from the lunar surface is a mixing model consisting of varying amounts of diffuse and specular components as shown in Figure 1. The specular component, which consists of only opposite-sense circular (OC) echoes, results from the mirror-like surface and sub-surface layers that are smooth to a tenth of a radar wavelength for large (>10 wavelengths) areas oriented perpendicular to the radar's line-ofsight. The diffuse component, which has both OC and same sense (SC) circular echoes, is associated with either surface roughness (wavelength-sized rocks) or ice, and is assumed to be uniformly bright, with backscatter being proportional to the cosine of the incidence angle. Only diffuse scattering contributes to the SC echoes.

  7. Wetting properties of molecularly rough surfaces

    NASA Astrophysics Data System (ADS)

    Svoboda, Martin; Malijevský, Alexandr; Lísal, Martin

    2015-09-01

    We employ molecular dynamics simulations to study the wettability of nanoscale rough surfaces in systems governed by Lennard-Jones (LJ) interactions. We consider both smooth and molecularly rough planar surfaces. Solid substrates are modeled as a static collection of LJ particles arranged in a face-centered cubic lattice with the (100) surface exposed to the LJ fluid. Molecularly rough solid surfaces are prepared by removing several strips of LJ atoms from the external layers of the substrate, i.e., forming parallel nanogrooves on the surface. We vary the solid-fluid interactions to investigate strongly and weakly wettable surfaces. We determine the wetting properties by measuring the equilibrium droplet profiles that are in turn used to evaluate the contact angles. Macroscopic arguments, such as those leading to Wenzel's law, suggest that surface roughness always amplifies the wetting properties of a lyophilic surface. However, our results indicate the opposite effect from roughness for microscopically corrugated surfaces, i.e., surface roughness deteriorates the substrate wettability. Adding the roughness to a strongly wettable surface shrinks the surface area wet with the liquid, and it either increases or only marginally affects the contact angle, depending on the degree of liquid adsorption into the nanogrooves. For a weakly wettable surface, the roughness changes the surface character from lyophilic to lyophobic due to a weakening of the solid-fluid interactions by the presence of the nanogrooves and the weaker adsorption of the liquid into the nanogrooves.

  8. 7 CFR 51.1873 - Slightly rough.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946... Standards for Fresh Tomatoes 1 Definitions § 51.1873 Slightly rough. Slightly rough means that the tomato...

  9. Roughness configuration matters for aeolian sediment flux

    USDA-ARS?s Scientific Manuscript database

    The parameterisation of surface roughness effects on aeolian sediment transport is a key source of uncertainty in wind erosion models. Roughness effects are typically represented by bulk drag-partitioning schemes that scale the threshold friction velocity (u*t) for soil entrainment by the ratio of s...

  10. Specular Reflection from Rough Surfaces Revisited

    ERIC Educational Resources Information Center

    Yasuda, Kensei; Kim, Alvin; Cho, Hayley; Timofejev, Timofej; Walecki, Wojciech J.; Klep, James; Edelson, Amy S.; Walecki, Abigail S.; Walecki, Eve S.; Walecki, Peter S.

    2016-01-01

    In his beautiful paper, Hasan Fakhruddin reported observations of mirror-like reflections in the rough surface of a ground glass plate. Similar effects have been recently employed for metrology of the roughness of optical diffusers used in modern light emitting device illumination systems. We report the observations of specular reflection in…

  11. Wetting properties of molecularly rough surfaces

    SciTech Connect

    Svoboda, Martin; Lísal, Martin; Malijevský, Alexandr

    2015-09-14

    We employ molecular dynamics simulations to study the wettability of nanoscale rough surfaces in systems governed by Lennard-Jones (LJ) interactions. We consider both smooth and molecularly rough planar surfaces. Solid substrates are modeled as a static collection of LJ particles arranged in a face-centered cubic lattice with the (100) surface exposed to the LJ fluid. Molecularly rough solid surfaces are prepared by removing several strips of LJ atoms from the external layers of the substrate, i.e., forming parallel nanogrooves on the surface. We vary the solid-fluid interactions to investigate strongly and weakly wettable surfaces. We determine the wetting properties by measuring the equilibrium droplet profiles that are in turn used to evaluate the contact angles. Macroscopic arguments, such as those leading to Wenzel’s law, suggest that surface roughness always amplifies the wetting properties of a lyophilic surface. However, our results indicate the opposite effect from roughness for microscopically corrugated surfaces, i.e., surface roughness deteriorates the substrate wettability. Adding the roughness to a strongly wettable surface shrinks the surface area wet with the liquid, and it either increases or only marginally affects the contact angle, depending on the degree of liquid adsorption into the nanogrooves. For a weakly wettable surface, the roughness changes the surface character from lyophilic to lyophobic due to a weakening of the solid-fluid interactions by the presence of the nanogrooves and the weaker adsorption of the liquid into the nanogrooves.

  12. Specular Reflection from Rough Surfaces Revisited

    ERIC Educational Resources Information Center

    Yasuda, Kensei; Kim, Alvin; Cho, Hayley; Timofejev, Timofej; Walecki, Wojciech J.; Klep, James; Edelson, Amy S.; Walecki, Abigail S.; Walecki, Eve S.; Walecki, Peter S.

    2016-01-01

    In his beautiful paper, Hasan Fakhruddin reported observations of mirror-like reflections in the rough surface of a ground glass plate. Similar effects have been recently employed for metrology of the roughness of optical diffusers used in modern light emitting device illumination systems. We report the observations of specular reflection in…

  13. Hydrodynamics and Roughness of Irregular Boundaries

    DTIC Science & Technology

    2011-01-01

    principle component analysis (PCA) similar to that used by Preston (2009) for ship- mounted multibeam data. Several variables derived from the...complex boundaries as well as characterization of acoustic and optical processes. Turbulent processes at the seabed are at the foundation of littoral...nearshore hydrodynamics, turbulence over rough beds influences optical and acoustic properties. Bed roughness also directly affects acoustic propagation in

  14. Playing Along the Edge

    NASA Image and Video Library

    2016-08-13

    Strands and arches of plasma streamed above the edge of the Sun for over a day, pulled by powerful magnetic forces (Aug. 11-12, 2016). The tug and pull of material heated to about 60,000 degrees C. was viewed in extreme ultraviolet light. This kind of dynamic flow of materials is rather common, though this grouping was larger than most. http://photojournal.jpl.nasa.gov/catalog/PIA17913

  15. Edge turbulence in tokamaks

    NASA Astrophysics Data System (ADS)

    Nedospasov, A. V.

    1992-12-01

    Edge turbulence is of decisive importance for the distribution of particle and energy fluxes to the walls of tokamaks. Despite the availability of extensive experimental data on the turbulence properties, its nature still remains a subject for discussion. This paper contains a review of the most recent theoretical and experimental studies in the field, including mainly the studies to which Wootton (A.J. Wooton, J. Nucl. Mater. 176 & 177 (1990) 77) referred to most in his review at PSI-9 and those published later. The available theoretical models of edge turbulence with volume dissipation due to collisions fail to fully interpret the entire combination of experimental facts. In the scrape-off layer of a tokamak the dissipation prevails due to the flow of current through potential shifts near the surface of limiters of divertor plates. The different origins of turbulence at the edge and in the core plasma due to such dissipation are discussed in this paper. Recent data on the electron temperature fluctuations enabled one to evaluate the electric probe measurements of turbulent flows of particles and heat critically. The latest data on the suppression of turbulence in the case of L-H transitions are given. In doing so, the possibility of exciting current instabilities in biasing experiments (rather than only to the suppression of existing turbulence) is given some attention. Possible objectives of further studies are also discussed.

  16. Specular Reflection from Rough Surfaces Revisited

    NASA Astrophysics Data System (ADS)

    Yasuda, Kensei; Kim, Alvin; Cho, Hayley; Timofejev, Timofej; Walecki, Wojciech J.; Klep, James; Edelson, Amy S.; Walecki, Abigail S.; Walecki, Eve S.; Walecki, Peter S.

    2016-10-01

    In his beautiful paper, Hasan Fakhruddin reported observations of mirror-like reflections in the rough surface of a ground glass plate. Similar effects have been recently employed for metrology of the roughness of optical diffusers used in modern light emitting device illumination systems. We report the observations of specular reflection in nontransparent rough surfaces at oblique angles, where roughness was treated as a variable. We present a simple trigonometry-based model explaining the observed phenomenon, which we experimentally validated using aluminum surfaces that have controlled roughness. The reported demonstration requires no special equipment, other than cellphone cameras, dielectric or metal plate, and sandpaper, and serves as an introduction to wave optics. This activity can be used to get further insight into everyday applications of wave optics for students already familiar with wave optics fundamentals.

  17. Modeling surface roughness scattering in metallic nanowires

    SciTech Connect

    Moors, Kristof; Sorée, Bart; Magnus, Wim

    2015-09-28

    Ando's model provides a rigorous quantum-mechanical framework for electron-surface roughness scattering, based on the detailed roughness structure. We apply this method to metallic nanowires and improve the model introducing surface roughness distribution functions on a finite domain with analytical expressions for the average surface roughness matrix elements. This approach is valid for any roughness size and extends beyond the commonly used Prange-Nee approximation. The resistivity scaling is obtained from the self-consistent relaxation time solution of the Boltzmann transport equation and is compared to Prange-Nee's approach and other known methods. The results show that a substantial drop in resistivity can be obtained for certain diameters by achieving a large momentum gap between Fermi level states with positive and negative momentum in the transport direction.

  18. Ice Accretion Roughness Measurements and Modeling

    NASA Technical Reports Server (NTRS)

    McClain, Stephen T.; Vargas, Mario; Tsao, Jen-Ching; Broeren, Andy P.; Lee, Sam

    2017-01-01

    Roughness on aircraft ice accretions is very important to the overall ice accretion process and to the resulting degradation in aircraft aerodynamic performance. Roughness enhances the local convection leading to more rapid ice accumulation rates, and roughness generates local flow perturbations that lead to higher skin friction. This paper presents 1) a review of the developments in ice shape three-dimensional laser scanning developed at NASA Glenn, 2) a review of the approach of McClain and Kreeger employed to characterize ice roughness evolution on an airfoil surface, and 3) a review of the experimental efforts that have been performed over the last five years to characterize, scale, and model ice roughness evolution physics.

  19. Determination of the interfacial roughness exponent in rare-earth superlattices

    SciTech Connect

    Swaddling, P.P.; McMorrow, D.F.; Cowley, R.A.; Ward, R.C.C.; Wells, M.R. Riso National Laboratory, DK-4000 Roskilde )

    1994-10-17

    The interfacial roughness in Ho/Y and Ho/Lu superlattices has been studied using high-resolution x-ray diffraction. The transverse width of the superlattice Bragg peaks broadens almost linearly as a function of the component of the reduced wave vector parallel to the growth direction, while the line shape is invariant, and is described by a Lorentzian raised to the power of [approx]5/2. These results are interpreted as a signature of conformally rough interfaces, and the roughness exponent is determined to be [alpha]=0.85[plus minus]0.05. It is also shown how [alpha] may be altered by adjusting the growth conditions.

  20. Geometrical exponents of contour loops on synthetic multifractal rough surfaces: multiplicative hierarchical cascade p model.

    PubMed

    Hosseinabadi, S; Rajabpour, M A; Movahed, M Sadegh; Allaei, S M Vaez

    2012-03-01

    In this paper, we study many geometrical properties of contour loops to characterize the morphology of synthetic multifractal rough surfaces, which are generated by multiplicative hierarchical cascading processes. To this end, two different classes of multifractal rough surfaces are numerically simulated. As the first group, singular measure multifractal rough surfaces are generated by using the p model. The smoothened multifractal rough surface then is simulated by convolving the first group with a so-called Hurst exponent, H*. The generalized multifractal dimension of isoheight lines (contours), D(q), correlation exponent of contours, x(l), cumulative distributions of areas, ξ, and perimeters, η, are calculated for both synthetic multifractal rough surfaces. Our results show that for both mentioned classes, hyperscaling relations for contour loops are the same as that of monofractal systems. In contrast to singular measure multifractal rough surfaces, H* plays a leading role in smoothened multifractal rough surfaces. All computed geometrical exponents for the first class depend not only on its Hurst exponent but also on the set of p values. But in spite of multifractal nature of smoothened surfaces (second class), the corresponding geometrical exponents are controlled by H*, the same as what happens for monofractal rough surfaces.

  1. Smooth at one end and rough at the other: influence of object texture on grasping behaviour.

    PubMed

    Glowania, Catharina; van Dam, L C J; Brenner, E; Plaisier, M A

    2017-06-21

    When picking up objects using a pinch grip, there are usually numerous places at which one could place the thumb and index finger. Yet, people seem to consistently place them at or close to the centre of mass (COM), presumably to minimize torque and therefore the required grip force. People also prefer to grasp objects by parallel surfaces and ones with higher friction coefficients (rough surfaces), to prevent the object from slipping when they lift it. Here, we examine the trade-off between friction and COM. Participants were asked to grasp and lift aluminium bars of which one end was polished and therefore smooth and the other was rough. Their finger positions were recorded to determine how they grasped the objects. The bars were oriented horizontally in the frontal plane, with the centre aligned with the participants' body midline. The bars varied in the horizontal offset between the COM and the edge of the rough region. The offset could be 0, 1 or 2 cm. We expected participants to grasp closer to the rough area than the centre of the bar. Completely rough bars and completely smooth bars served as control conditions. The slipperiness of the surface that was grasped affected the height of the grasping points, indicating that participants adjusted their grasping behaviour to the slipperiness of the surface. However, the tendency to grasp closer to the rough area was minimal. This shows that the judged COM largely determines how an object is grasped. Friction has very limited influence.

  2. Simulation of the effect of anode surface roughness on diagnostic x-ray spectra.

    PubMed

    Nowotny, R; Meghzifene, Kh

    2002-11-21

    To simulate the effect of the condition of the anode surface on x-ray output the surface roughness of anode fragments of replaced clinical x-ray tubes was determined. A mean roughness of 1.32-5.22 microm giving effective tungsten absorption layers of up to 18 microm thickness in the direction of the x-ray beam was determined. X-ray spectra were then simulated using the measured surface profiles. The most prominent effect was the reduction of the kerma output of the tube with increasing roughness (-33% at 50 kV tube voltage and 5 microm roughness). The effects of beam hardening are less pronounced. The corresponding changes in the spectral parameters are generally small but largest for tube voltages up to 70 kV. For higher voltages the increased photon attenuation above the K-edge of tungsten reduces the effects of roughness on spectral parameters. The maximum shifts in mean photon energy of about 1 keV and in HVL of about 0.2 mm Al were obtained for an anode roughness of 5 microm.

  3. Observations on Leading-Edge Vortex Development

    NASA Astrophysics Data System (ADS)

    Glenn, Michael; Lang, Amy; Wahidi, Redha; Wilroy, Jacob

    2016-11-01

    Most of an insect's lift comes from the leading edge vortex (LEV) that they produce when flapping their wings. There are many variables that make a LEV either stronger or weaker such as: roughness from the scales on their wings, angle of attack (AoA) of wing, size of the wing, and speed of the wing during flapping motion. Experiments were conducted to study LEV development to gain a better understanding of butterfly flight and the importance of LEV formation. The variables emphasized in this particular experiment were the chord length Reynolds numbers. Two smooth plates of 4 inches and 7 inches were compared in this experiment with Re of 1500 and 3000. Matlab was used to track the LEV location and calculate the vorticity and circulation magnitudes. Differences in LEV vortex strength as a function of chord length will be presented. Funding was provided by NSF REU site Grant EEC 1358991 and CBET Grant 1628600.

  4. A fast line-by-line method.

    NASA Astrophysics Data System (ADS)

    Mitsel, A. A.; Firsov, K. M.

    1995-09-01

    A new spectral line selection algorithm is developed. The algorithm makes it possible to decrease the number of spectral lines with the increase in altitude. In order for the computer code based on a line-by-line method to operate efficiently two line selections must be carried out. The first selection is rough. This enables the most weak lines not contributing to the optical thickness of the layer z1-z2 to be eliminated. The other lines are subjected to the second selection. In this case the maximum height up to which the line should be taken into account is determined. At the same time for each line at each altitude the maximum resonance frequency difference within the limits of which the contribution of the line to absorption should be taken into account is determined. The gain in the time of calculation of the integral transmittance may be of five times or greater. The calculation error of the integral transmittance is not larger than 0.5%.

  5. Simulation studies of structure and edge tension of lipid bilayer edges: effects of tail structure and force-field.

    PubMed

    West, Ana; Ma, Kevin; Chung, Jonathan L; Kindt, James T

    2013-08-15

    Molecular dynamics simulations of lipid bilayer ribbons have been performed to investigate the structures and line tensions associated with free bilayer edges. Simulations carried out for dioleoyl phosphatidylcholine with three different force-field parameter sets yielded edge line tensions of 45 ± 2 pN, over 50% greater than the most recently reported experimentally determined value for this lipid. Edge tensions obtained from simulations of a series of phosphatidylcholine lipid bilayer ribbons with saturated acyl tails of length 12-16 carbons and with monounsaturated acyl tails of length 14-18 carbons could be correlated with the excess area associated with forming the edge, through a two-parameter fit. Saturated-tail lipids underwent local thickening near the edge, producing denser packing that correlated with lower line tensions, while unsaturated-tail lipids showed little or no local thickening. In a dipalmitoyl phosphatidylcholine ribbon initiated in a tilted gel-phase structure, lipid headgroups tended to tilt toward the nearer edge producing a herringbone pattern, an accommodation that may account for the reported edge-induced stabilization of an ordered structure at temperatures near a lipid gel-fluid phase transition.

  6. 49 CFR 179.201-3 - Lined tanks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... lining, at least 5/32-inch thick, except overall rivets and seams formed by riveted attachments in the lining must be double thickness. The rubber lining must overlap at least 11/2 inches at all edges which must be straight and be beveled to an angle of approximately 45°, or butted edges of lining must...

  7. Magnetic correlations at graphene edges: basis for novel spintronics devices.

    PubMed

    Yazyev, Oleg V; Katsnelson, M I

    2008-02-01

    Magnetic zigzag edges of graphene are considered as a basis for novel spintronics devices despite the fact that no true long-range magnetic order is possible in one dimension. We study the transverse and longitudinal fluctuations of magnetic moments at zigzag edges of graphene from first principles. We find a high value for the spin wave stiffness D=2100 meV A2 and a spin-collinear domain wall creation energy E(dw)=114 meV accompanied by low magnetic anisotropy. Above the crossover temperature T(x) approximately 10 K, the spin correlation length xi proportional, variantT(-1) limits the long-range magnetic order to approximately 1 nm at 300 K while below T(x), it grows exponentially with decreasing temperature. We discuss possible ways of increasing the range of magnetic order and effects of edge roughness on it.

  8. Liver ultrasound image classification by using fractal dimension of edge

    NASA Astrophysics Data System (ADS)

    Moldovanu, Simona; Bibicu, Dorin; Moraru, Luminita

    2012-08-01

    Medical ultrasound image edge detection is an important component in increasing the number of application of segmentation, and hence it has been subject of many studies in the literature. In this study, we have classified the liver ultrasound images (US) combining Canny and Sobel edge detectors with fractal analysis in order to provide an indicator about of the US images roughness. We intend to provide a classification rule of the focal liver lesions as: cirrhotic liver, liver hemangioma and healthy liver. For edges detection the Canny and Sobel operators were used. Fractal analyses have been applied for texture analysis and classification of focal liver lesions according to fractal dimension (FD) determined by using the Box Counting method. To assess the performance and accuracy rate of the proposed method the contrast-to-noise (CNR) is analyzed.

  9. Development of X-43A Mach 10 Leading Edges

    NASA Technical Reports Server (NTRS)

    Ohlhorst, Craig W.; Glass, David E.; Bruce, Walter E., III; Lindell, Michael C.; Vaughn, Wallace L.; Dirling, R. B., Jr.; Hogenson, P. A.; Nichols, J. M.; Risner, N. W.; Thompson, D. R.

    2005-01-01

    The nose leading edge of the Hyper-X Mach 10 vehicle was orginally anticipated to reach temperatures near 4000 F at the leading-edge stagnation line. A SiC coated carbon/carbon (C/C) leading-edge material will not survive that extreme temperature for even a short duration single flight. To identify a suitable leading edge for the Mach 10 vehicle, arc-jet testing was performed on thirteen leading-edge segments fabricated from different material systems to evaluate their performance in a simulated flight environment. Hf, Zr, Si, and Ir based materials, in most cases as a coating on C/C, were included in the evaluation. Afterwards, MER, Tucson, AZ was selected as the supplier of the flight vehicle leading edges. The nose and the vertical and horizontal tail leading edges were fabricated out of a 3:1 biased high thermal conductivity C/C. The leading edges were coated with a three layer coating comprised of a SiC conversion of the top surface of the C/C, followed by a chemical vapor deposited layer of SiC, followed by a thin chemical vapor deposited layer of HfC. This paper will describe the fabrication of the Mach 10 C/C leading edges and the testing performed to validate performance.

  10. Effects of surface roughness on shear viscosity.

    PubMed

    Papanikolaou, Michail; Frank, Michael; Drikakis, Dimitris

    2017-03-01

    This paper investigates the effect of surface roughness on fluid viscosity using molecular dynamics simulations. The three-dimensional model consists of liquid argon flowing between two solid walls whose surface roughness was modeled using fractal theory. In tandem with previously published experimental work, our results show that, while the viscosity in smooth channels remains constant across the channel width, in the presence of surface roughness it increases close to the walls. The increase of the boundary viscosity is further accentuated by an increase in the depth of surface roughness. We attribute this behavior to the increased momentum transfer at the boundary, a result of the irregular distribution of fluid particles near rough surfaces. Furthermore, although the viscosity in smooth channels has previously been shown to be independent of the strength of the solid-liquid interaction, here we show that in the presence of surface roughness, the boundary viscosity increases with the solid's wettability. The paper concludes with an analytical description of the viscosity as a function of the distance from the channel walls, the walls' surface roughness, and the solid's wetting properties. The relation can potentially be used to adjust the fluid dynamics equations for a more accurate description of microfluidic systems.

  11. Effects of surface roughness on shear viscosity

    NASA Astrophysics Data System (ADS)

    Papanikolaou, Michail; Frank, Michael; Drikakis, Dimitris

    2017-03-01

    This paper investigates the effect of surface roughness on fluid viscosity using molecular dynamics simulations. The three-dimensional model consists of liquid argon flowing between two solid walls whose surface roughness was modeled using fractal theory. In tandem with previously published experimental work, our results show that, while the viscosity in smooth channels remains constant across the channel width, in the presence of surface roughness it increases close to the walls. The increase of the boundary viscosity is further accentuated by an increase in the depth of surface roughness. We attribute this behavior to the increased momentum transfer at the boundary, a result of the irregular distribution of fluid particles near rough surfaces. Furthermore, although the viscosity in smooth channels has previously been shown to be independent of the strength of the solid-liquid interaction, here we show that in the presence of surface roughness, the boundary viscosity increases with the solid's wettability. The paper concludes with an analytical description of the viscosity as a function of the distance from the channel walls, the walls' surface roughness, and the solid's wetting properties. The relation can potentially be used to adjust the fluid dynamics equations for a more accurate description of microfluidic systems.

  12. The influence of surface roughness on cloud cavitation flow around hydrofoils

    NASA Astrophysics Data System (ADS)

    Hao, Jiafeng; Zhang, Mindi; Huang, Xu

    2017-08-01

    The aim of this study is to investigate experimentally the effect of surface roughness on cloud cavitation around Clark-Y hydrofoils. High-speed video and particle image velocimetry (PIV) were used to obtain cavitation patterns images (Prog. Aerosp. Sci. 37: 551-581, 2001), as well as velocity and vorticity fields. Results are presented for cloud cavitating conditions around a Clark-Y hydrofoil fixed at angle of attack of α =8{°} for moderate Reynolds number of Re=5.6 × 105 . The results show that roughness had a great influence on the pattern, velocity and vorticity distribution of cloud cavitation. For cavitating flow around a smooth hydrofoil (A) and a rough hydrofoil (B), cloud cavitation occurred in the form of finger-like cavities and attached subulate cavities, respectively. The period of cloud cavitation around hydrofoil A was shorter than for hydrofoil B. Surface roughness had a great influence on the process of cloud cavitation. The development of cloud cavitation around hydrofoil A consisted of two stages: (1) Attached cavities developed along the surface to the trailing edge; (2) A reentrant jet developed, resulting in shedding and collapse of cluster bubbles or vortex structure. Meanwhile, its development for hydrofoil B included three stages: (1) Attached cavities developed along the surface to the trailing edge, with accumulation and rotation of bubbles at the trailing edge of the hydrofoil affecting the flow field; (2) Development of a reentrant jet resulted in the first shedding of cavities. Interaction and movement of flows from the pressure side and suction side brought liquid water from the pressure side to the suction side of the hydrofoil, finally forming a reentrant jet. The jet kept moving along the surface to the leading edge of the hydrofoil, resulting in large-scale shedding of cloud bubbles. Several vortices appeared and dissipated during the process; (3) Cavities grew and shed again.

  13. Blanks: a computer program for analyzing furniture rough-part needs in standard-size blanks

    Treesearch

    Philip A. Araman

    1983-01-01

    A computer program is described that allows a company to determine the number of edge-glued, standard-size blanks required to satisfy its rough-part needs for a given production period. Yield and cost information also is determined by the program. A list of the program inputs, outputs, and uses of outputs is described, and an example analysis with sample output is...

  14. X-point position dependence of edge intrinsic toroidal rotation on the Tokamak à Configuration Variable

    SciTech Connect

    Stoltzfus-Dueck, T.; Karpushov, A. N.; Sauter, O.; Duval, B. P.; Labit, B.; Reimerdes, H.; Vijvers, W. A. J.; Camenen, Y.

    2015-05-15

    Recent theoretical work predicts intrinsic toroidal rotation in the tokamak edge to depend strongly on the normalized major radial position of the X-point. With this motivation, we conducted a series of Ohmic L-mode shots on the Tokamak à Configuration Variable, moving the X-point from the inboard to the outboard edge of the last closed flux surface in both lower and upper single null configurations. The edge toroidal rotation evolved from strongly co-current for an inboard X-point to either vanishing or counter-current for an outboard X-point, in agreement with the theoretical expectations. The whole rotation profile shifted roughly rigidly with the edge rotation, resulting in variation of the peak core rotation by more than a factor of two. Core rotation reversals had little effect on the edge rotation. Edge rotation was slightly more counter-current for unfavorable than favorable ∇B drift discharges.

  15. Partnership for Edge Physics Simulation (EPSI)

    SciTech Connect

    Schroder, Peter

    2015-02-11

    We propose to develop advanced simulation codes, based upon an extreme parallelism, first principles kinetic approach, to address the challenges associated with the edge region of magnetically confined plasmas. This work is relevant to both existing magnetic fusion facilities and essential for next-generation burning plasma experiments, such as ITER where success is critically dependent upon H-mode operation achieving an edge pedestal of sufficient height for good core plasma performance without producing deleterious large scale edge localized instabilities. The plasma edge presents a well-known set of multi-physics, multi-scale problems involving complex 3D magnetic geometry. Perhaps the greatest computational challenge is the lack of scale separation – temporal scales for drift waves, Alfven waves, ELM dynamics for example have strong overlap. Similar overlap occurs on the spatial scales for the ion poloidal gyro-radius, drift wave and pedestal width. The traditional approach of separating fusion problems into weakly interacting spatial or temporal domains clearly breaks down in the edge. A full kinetic model (full-f model) must be solved to understand and predict the edge physics including non-equilibrium thermodynamic issues arising from the magnetic topology (the open field lines producing a spatially sensitive velocity hole), plasma wall interactions, neutral and atomic physics. The plan here is to model these phenomena within a comprehensive first principles set of equations without the need for the insurmountable multiple-codes coupling issues by building on the XGC1 code developed under the SciDAC Proto-FSP Center for Plasma Edge Simulation (CPES). This proposal includes the critical participants in the XGC1 development. We propose enhancing the capability of XGC1 by including all the important turbulence physics contained in kinetic ion and electron electromagnetic dynamics, by extending the PIC technology to incorporate several positive features found

  16. A prototype scanning system for optimal edging and trimming of rough hardwood lumber

    Treesearch

    Sang-Mook Lee; A. Lynn Abbott; Philip A. Araman; Daniel L. Schmoldt

    2003-01-01

    This paper is concerned with scanning and assessment of hardwood lumber early in the manufacturing process. Scanning operations that take place immediately after the headrig have significantly greater potential to reduce loss and improve economic value, as compared to scanning that is performed during subsequent manufacturing steps. In spite of this, the scanning of...

  17. A system for optimal edging and trimming of rough hardwood lumber

    Treesearch

    Sang-Mook Lee; A. Lynn Abbott; Daniel L. Schmoldt; Philip A. Araman

    2003-01-01

    Despite the importance of improving lumber processing early in manufacturing, scanning of unplaned, green hardwood lumber has received relatively little attention in the research community. This has been due in part to the difficulty of clearly imaging fresh-cut boards whose fibrous surfaces mask many wood features. This paper describes a prototype system that scans...

  18. Competing edge networks

    NASA Astrophysics Data System (ADS)

    Parsons, Mark; Grindrod, Peter

    2012-06-01

    We introduce a model for a pair of nonlinear evolving networks, defined over a common set of vertices, subject to edgewise competition. Each network may grow new edges spontaneously or through triad closure. Both networks inhibit the other's growth and encourage the other's demise. These nonlinear stochastic competition equations yield to a mean field analysis resulting in a nonlinear deterministic system. There may be multiple equilibria; and bifurcations of different types are shown to occur within a reduced parameter space. This situation models competitive communication networks such as BlackBerry Messenger displacing SMS; or instant messaging displacing emails.

  19. Receptivity to Roughness, Acoustic, and Vortical Disturbances in Supersonic Boundary Layers Over Swept Wings

    NASA Technical Reports Server (NTRS)

    Balakumar, Ponnampalam; King, Rudolph A.

    2011-01-01

    The receptivity and interaction of stationary and traveling crossflow instability of three-dimensional supersonic boundary layers over a swept biconvex wing with a blunt leading edge are numerically investigated for a freestream Mach number of 3. The steady and unsteady flow fields are obtained by solving the full Navier-Stokes equations. The receptivity of the boundary layer to surface roughness, freestream acoustic waves, and freestream vorticity waves are numerically investigated. The initial amplitudes of the stationary vortices generated by 1 micron roughness elements is about 2000 times larger than the initial amplitudes of the traveling disturbances generated by vortical disturbances. The interaction of stationary and traveling disturbances was investigated by solving the equations with both surface roughness and vortical disturbances. When the initial amplitudes of the stationary disturbances are large compared to the traveling disturbances, the stationary vortex dominates the perturbation field. When the amplitudes are comparable, the traveling vortex prevails and the stationary vortex is suppressed.

  20. Discrete-Roughness-Element-Enhanced Swept-Wing Natural Laminar Flow at High Reynolds Numbers

    NASA Technical Reports Server (NTRS)

    Malik, Mujeeb; Liao, Wei; Li, Fei; Choudhari, Meelan

    2015-01-01

    Nonlinear parabolized stability equations and secondary-instability analyses are used to provide a computational assessment of the potential use of the discrete-roughness-element technology for extending swept-wing natural laminar flow at chord Reynolds numbers relevant to transport aircraft. Computations performed for the boundary layer on a natural-laminar-flow airfoil with a leading-edge sweep angle of 34.6 deg, freestream Mach number of 0.75, and chord Reynolds numbers of 17 × 10(exp 6), 24 × 10(exp 6), and 30 × 10(exp 6) suggest that discrete roughness elements could delay laminar-turbulent transition by about 20% when transition is caused by stationary crossflow disturbances. Computations show that the introduction of small-wavelength stationary crossflow disturbances (i.e., discrete roughness element) also suppresses the growth of most amplified traveling crossflow disturbances.

  1. Relationships between topographic roughness and aeolian processes

    NASA Technical Reports Server (NTRS)

    Greeley, Ronald; Lancaster, N.; Gaddis, L.; Rasmussen, K. R.; White, B. R.; Saunders, R. S.; Wall, S.; Dobrovolskis, Anthony R.; Iversen, J. D.

    1991-01-01

    The interaction between winds and desert surfaces has important implications for sediment transport on Earth, Mars, and Venus, and for understanding the relationships between radar backscatter and aerodynamic roughness as part of the NASA Shuttle Imaging radar (SIR-C) Mission. Here, researchers report results from measurements of boundary layer wind profiles and surface roughness at sites in Death Valley and discuss their implications. The sites included a flat to undulating gravel and sand reg, alluvial fans, and a playa. Estimates of average particle size composition of Death Valley sites and arithmetic mean values of aerodynamic roughness are given in tabular form.

  2. Numerical Schemes for Rough Parabolic Equations

    SciTech Connect

    Deya, Aurelien

    2012-04-15

    This paper is devoted to the study of numerical approximation schemes for a class of parabolic equations on (0,1) perturbed by a non-linear rough signal. It is the continuation of Deya (Electron. J. Probab. 16:1489-1518, 2011) and Deya et al. (Probab. Theory Relat. Fields, to appear), where the existence and uniqueness of a solution has been established. The approach combines rough paths methods with standard considerations on discretizing stochastic PDEs. The results apply to a geometric 2-rough path, which covers the case of the multidimensional fractional Brownian motion with Hurst index H>1/3.

  3. Relationships between topographic roughness and aeolian processes

    NASA Astrophysics Data System (ADS)

    Greeley, Ronald; Lancaster, N.; Gaddis, L.; Rasmussen, K. R.; White, B. R.; Saunders, R. S.; Wall, S.; Dobrovolskis, Anthony R.; Iversen, J. D.

    1991-06-01

    The interaction between winds and desert surfaces has important implications for sediment transport on Earth, Mars, and Venus, and for understanding the relationships between radar backscatter and aerodynamic roughness as part of the NASA Shuttle Imaging radar (SIR-C) Mission. Here, researchers report results from measurements of boundary layer wind profiles and surface roughness at sites in Death Valley and discuss their implications. The sites included a flat to undulating gravel and sand reg, alluvial fans, and a playa. Estimates of average particle size composition of Death Valley sites and arithmetic mean values of aerodynamic roughness are given in tabular form.

  4. On possible resolutions of the micro-edge problem for a contact line moving on a solid in a pure-vapor atmosphere with no slip and without extended precursor films

    NASA Astrophysics Data System (ADS)

    Rednikov, Alexey; Colinet, Pierre

    2011-11-01

    At the previous APS/DFD meeting, we reported on the possibility of a singularity-free description of a moving contact line totally in the framework of classical physics (no disjoining pressure, no slip) thanks to the phase change whose intensity is regulated by Kelvin effect. Pushing this idea further, there remains a related more practical issue: the Kelvin effect, even though classical, becomes apparent at such small scales that the disjoining pressure (DP) may nonetheless play a significant role. Here we show, for a class of DP isotherms remaining finite at zero film thicknesses, that the same kind of natural singularity-resolution mechanism still holds. As before, we consider, in the framework of the lubrication theory and a classical one-sided model, a contact line moving at a constant velocity (advancing or receding) and starting abruptly at a (formally) bare solid surface, the micro-contact angle being either equal to zero or finite. Also touched upon is a possible resolution of the remaining integrable singularities within the paradigm of de Gennes and coworkers, considered here in another talk by the present authors, by means of regularizing the DP isotherm at very small thicknesses. Supported by ESA & BELSPO, by the EU, and by FRS-FNRS.

  5. Receptivity of Hypersonic Boundary Layers to Distributed Roughness and Acoustic Disturbances

    NASA Technical Reports Server (NTRS)

    Balakumar, P.

    2013-01-01

    Boundary-layer receptivity and stability of Mach 6 flows over smooth and rough seven-degree half-angle sharp-tipped cones are numerically investigated. The receptivity of the boundary layer to slow acoustic disturbances, fast acoustic disturbances, and vortical disturbances is considered. The effects of three-dimensional isolated roughness on the receptivity and stability are also simulated. The results for the smooth cone show that the instability waves are generated in the leading edge region and that the boundary layer is much more receptive to slow acoustic waves than to the fast acoustic waves. Vortical disturbances also generate unstable second modes, however the receptivity coefficients are smaller than that of the slow acoustic wave. Distributed roughness elements located near the nose region decreased the receptivity of the second mode generated by the slow acoustic wave by a small amount. Roughness elements distributed across the continuous spectrum increased the receptivity of the second mode generated by the slow and fast acoustic waves and the vorticity wave. The largest increase occurred for the vorticity wave. Roughness elements distributed across the synchronization point did not change the receptivity of the second modes generated by the acoustic waves. The receptivity of the second mode generated by the vorticity wave increased in this case, but the increase is lower than that occurred with the roughness elements located across the continuous spectrum. The simulations with an isolated roughness element showed that the second mode waves generated by the acoustic disturbances are not influenced by the small roughness element. Due to the interaction, a three-dimensional wave is generated. However, the amplitude is orders of magnitude smaller than the two-dimensional wave.

  6. Boundary-layer receptivity to three-dimensional roughness arrays on a swept-wing

    NASA Astrophysics Data System (ADS)

    Hunt, Lauren Elizabeth

    On-going efforts to reduce aircraft drag through transition delay focus on understanding the process of boundary-layer transition from a physics-based perspective. For swept-wings subject to transition dominated by a stationary crossflow instability, one of the remaining challenges is understanding how freestream disturbances and surface features such as surface roughness create the initial amplitudes for unstable waves. These waves grow, modify the mean flow and create conditions for secondary instabilities to occur, which in turn ultimately lead to transition. Computational methods that model the primary and secondary instability growth can accurately model disturbance evolution as long as appropriate initial conditions are supplied. Additionally, transition delay using discrete roughness arrays that exploit known sensitivities to surface roughness has been demonstrated in flight and wind tunnel testing; however, inconsistencies in performance from the two test platforms indicate further testing is required. This study uses detailed hotwire boundary-layer velocity scans to quantify the relationship between roughness height and initial disturbance amplitude. Naphthalene flow visualization provides insight into how transition changes as a result of roughness height and spacing. Micron-sized, circular roughness elements were applied near the leading edge of the ASU(67)-0315 model installed at an angle of attack of -2.9° in the Klebanoff-Saric Wind Tunnel. Extensive flow quality measurements show turbulence intensities less than 0.02% over the speed range of interest. A survey of multiple roughness heights for the most unstable and control wavelengths and Reynolds numbers of 2.4 x 106, 2.8 x 106 and 3.2 x 106 was completed for chord locations of 10%, 15% and 20%. When care was taken to measure in the region of linear stability, it was found that the disturbance amplitude varies almost linearly with roughness height. Naphthalene flow visualization indicates that

  7. Rough analysis of installation effects on turboprop noise

    NASA Technical Reports Server (NTRS)

    Durbin, P. A.; Groeneweg, J. F.

    1982-01-01

    A rough analysis of noise from a propeller operated at angle of attack, and in the nonuniform flow due to a line vortex approximating a wing flow field suggests installation can significantly affect turboprop noise levels. On one side of the propeller, where the blades approach the horizontal plane from above, decreases of noise occur; while on the other side noise increases. The noise reduction is due to negative interference of steady and unsteady sources. An angle of attack, or distance between propeller and vortex, exists for which noise is a minimum.

  8. MHD edge instabilities in toroidal plasmas

    NASA Astrophysics Data System (ADS)

    Sugiyama, Linda

    2015-11-01

    Different types of MHD edge instabilities in different toroidal magnetically confined plasmas are compared. Large scale numerical simulations show that the nonlinear evolution of an unstable edge mode in a shaped plasma with a single X-point and a surrounding open field line region has a number of common features in the full resistive MHD model for strongly unstable and weaker instabilities. These include the relation of the nonlinear mode structure and dominant toroidal harmonics to the linear eigenmode spectrum, the effects of the mode on reducing the edge pressure or density gradient, the inward penetration of a ballooning-type perturbation into the plasma interior, and the potential to drive a coherent axisymmetric poloidal rotation of the outer part of the plasma, exhibited at different strengths. The results can be compared to experiment to estimate the usefulness and validity of the MHD model for predicting edge stability and instability properties. Work supported by the U.S. DOE OFES under Awards DE-SC-0007883, DE-FG02-04ER54802, and DE-SC-0008737. Some computation carried out at NERSC.

  9. Effectiveness and tolerability of second-line treatment with vildagliptin versus other oral drugs for type 2 diabetes in a real-world setting in the Middle East: results from the EDGE study

    PubMed Central

    Saab, Charles; Al-Saber, Feryal A; Haddad, Jihad; Jallo, Mahir Khalil; Steitieh, Habib; Bader, Giovanni; Ibrahim, Mohamed

    2015-01-01

    Background Type 2 diabetes mellitus (T2DM) is a chronic progressive disease that requires treatment intensification with antihyperglycemic agents due to progressive deterioration of β-cell function. A large observational study of 45,868 patients with T2DM across 27 countries (EDGE) assessed the effectiveness and safety of vildagliptin as add-on to other oral antidiabetic drugs (OADs) versus other comparator OAD combinations. Here, we present results from the Middle East countries (Bahrain, Jordan, Kuwait, Lebanon, Oman, Palestine, and the United Arab Emirates). Methods Patients inadequately controlled with OAD monotherapy were eligible after the add-on treatment was chosen by the physician based on clinical judgment and patient need. Patients were assigned to either vildagliptin or comparator OADs (sulfonylureas, thiazolidinediones, glinides, α-glucosidase inhibitors, or metformin, except incretin-based therapies) based on the add-on therapy. The primary endpoint was the proportion of patients achieving a glycated hemoglobin (HbA1c) reduction of >0.3% without peripheral edema, hypoglycemia, discontinuation due to a gastrointestinal event, or weight gain ≥5%. One of the secondary endpoints was the proportion of patients achieving HbA1c <7% without hypoglycemia or weight gain. Change in HbA1c from baseline to study endpoint and safety were also assessed. Results Of the 4,780 patients enrolled in the Middle East, 2,513 received vildagliptin and 2,267 received other OADs. Overall, the mean (± standard deviation) age at baseline was 52.1±10.2 years, mean HbA1c was 8.5%±1.3%, and mean T2DM duration was 4.2±4.0 years. The proportion of patients achieving the primary (76.1% versus 61.6%, P<0.0001) and secondary (54.8% versus 29.9%, P<0.0001) endpoints was higher with vildagliptin than with the comparator OADs. The unadjusted odds ratios for the primary and secondary endpoints were 1.98 (95% confidence interval 1.75–2.25) and 2.8 (95% confidence interval 2.5–3

  10. Combined Effect of Surface Roughness and Wake Splitter Plate on the Aerodynamic Characteristics of a Circular Cylinder

    NASA Astrophysics Data System (ADS)

    Saisanthosh, Iyer; Arunkumar, K.; Ajithkumar, R.; Srikrishnan, A. R.

    2017-09-01

    This paper is focussed on numerical investigation of flow around a stationary circular cylinder (diameter, D) with selectively applied surface roughness (roughness strips with thickness ‘k’) in the presence of a wake splitter plate (length, L). The plate leading edge is at a distance of ‘G’ from the cylinder base. For this study, the commercial software ANSYS Fluent is used. Fluid considered is water. Study was conducted the following cases (a) plain cylinder (b) cylinder with surface roughness (without splitter plate) (c) Cylinder with splitter plate (without surface roughness) and (d) cylinder with both roughness and splitter plate employed. The study Reynolds number (based on D) is 17,000 and k/δ = 1.25 (in all cases). Results indicate that, for cylinder with splitter plate (no roughness), lift coefficient gradually drops till G/D=1.5 further to which it sharply increases. Whereas, drag coefficient and Strouhal number undergoes slight reduction till G/D=1.0 and thereafter, gradually increase. Circumferential location of strip (α) does not influence the aerodynamic parameters significantly. With roughness alone, drag is magnified by about 1.5 times and lift, by about 2.7 times that of the respective values of the smooth cylinder. With splitter plate, for roughness applied at all ‘α’ values, drag and lift undergoes substantial reduction with the lowest value attained at G/D=1.0.

  11. Edge reconstruction effect in pristine and H-passivated zigzag silicon carbide nanoribbons.

    PubMed

    Lou, Ping

    2011-10-14

    The edge reconstruction effect of the zigzag silicon carbide nanoribbons (zz SiC NRs) to a stable line of alternatively fused seven and five membered rings without and with H passivation have been studied using first principles density functional theory (DFT). The both side's edges of the pristine SiC are respectively terminated by Si and C atoms and are called the Si-edge and the C-edge, respectively. In the un-passivated systems, the C-edge reconstructed (Crc) could effectively lower the edge energy of the system, while the Si-edge reconstructed (Sirc) could raise the edge energy of the system. Thus, the Crc edge is the best edge for the edge reconstruction of the system, while the both edge reconstructed (brc) system is the metastability. Moreover, the brc system has a nonmagnetic metallic state, whereas the Crc system, as well as Sirc system, has a ferromagnetic metallic state. The edge reconstructed destroys the magnetic moment of the corresponding edge atoms. The magnetic moment arises from the unreconstructed zigzag edges. The pristine zz edge system has a ferrimagnetic metallic state. However, in the H-passivated systems, the unreconstructed zigzag edge (zz-H) is the best edge. The Crc-H system is the metastability. The Sirc-H system has only slightly higher energy than the Crc-H system, whereas the brc-H system of the pristine SiC NR has the highest edge energy. Thus, the H passivation would prevent the occurrence of edge reconstruction. Moreover, H passivation induces a metal-semiconductor transition in the zz and brc SiC NRs. Additionally, except for brc-H system which has non-magnetic semiconducting state, the zz-H, Crc-H, and Sirc-H systems have the magnetic state.

  12. Ellipsometric analysis for surface roughness and texture.

    PubMed

    Nee, S M

    1988-07-15

    A 2-D symmetric model is incorporated into the calculation of the ellipsometric parameters Psi and Delta for surface roughness and texture characterization based on the effective medium theory. The least-squares fits of the experimental data at a 5-microm IR wavelength for rough fused silica samples at multiple angles of incidence give the standard deviations of Psi and Delta of about twice the instrumental errors. The effective thickness and the depolarization factor obtained by ellipsometry agree with the roughness and average height-to-halfwidth ratio of voids obtained by stylus profilometry. The surface texture can be characterized by the fit depolarization factors set. The excellent agreement between theory and experiments indicates that ellipsometry can be a promising nondestructive technique for rough-surface evaluation.

  13. Rough Terrain on Rosetta Destination Comet

    NASA Image and Video Library

    2014-11-11

    Some relatively rough terrain on the nucleus of comet 67P/Churyumov-Gerasimenko appears in this image taken by the navigation camera on the European Space Agency Rosetta spacecraft in the second half of October 2014.

  14. The Surface Roughness of Terrains on Mars

    NASA Technical Reports Server (NTRS)

    Deal, K. S.; Arvidson, R. E.; Neumann, G. A.

    2003-01-01

    The RMS roughness measurements produced by Neumann et al. from Mars Orbiter Laser Altimeter (MOLA) data provide unique information about surface height variations at an effective length scale of < 75 m. Roughness at this scale is important not only for landing site safety considerations, but also for assessment of landscape evolution, which depends on emplacement mechanisms and erosional/depositional processes. Here we present an examination of the global surface roughness map with discussion of terrain types and potential formation and/or alteration mechanisms. Spatially coherent terrain types were identified based on inspection of the roughness map. These terrains were further characterized through analysis of morphology and geology using MOLA topography, MOC wide-angle, and MOC narrow-angle images as well as the geologic maps produced by Scott & Tanaka and Greeley & Guest. All of these data were used to explore potential formation and modification processes.

  15. Three-tier rough superhydrophobic surfaces.

    PubMed

    Cao, Yuanzhi; Yuan, Longyan; Hu, Bin; Zhou, Jun

    2015-08-07

    A three-tier rough superhydrophobic surface was fabricated by growing hydrophobic modified (fluorinated silane) zinc oxide (ZnO)/copper oxide (CuO) hetero-hierarchical structures on silicon (Si) micro-pillar arrays. Compared with the other three control samples with a less rough tier, the three-tier surface exhibits the best water repellency with the largest contact angle 161° and the lowest sliding angle 0.5°. It also shows a robust Cassie state which enables the water to flow with a speed over 2 m s(-1). In addition, it could prevent itself from being wetted by the droplet with low surface tension (mixed water and ethanol 1:1 in volume) which reveals a flow speed of 0.6 m s(-1) (dropped from the height of 2 cm). All these features prove that adding another rough tier on a two-tier rough surface could futher improve its water-repellent properties.

  16. Investigation on Surface Roughness in Cylindrical Grinding

    NASA Astrophysics Data System (ADS)

    Rudrapati, Ramesh; Bandyopadhyay, Asish; Pal, Pradip Kumar

    2011-01-01

    Cylindrical grinding is a complex machining process. And surface roughness is often a key factor in any machining process while considering the machine tool or machining performance. Further, surface roughness is one of the measures of the technological quality of the product and is a factor that greatly influences cost and quality. The present work is related to some aspects of surface finish in the context of traverse-cut cylindrical grinding. The parameters considered have been: infeed, longitudinal feed and work speed. Taguchi quality design is used to design the experiments and to identify the significantly import parameter(s) affecting the surface roughness. By utilization of Response Surface Methodology (RSM), second order differential equation has been developed and attempts have also been made for optimization of the process in the context of surface roughness by using C- programming.

  17. The Surface Roughness of Terrains on Mars

    NASA Technical Reports Server (NTRS)

    Deal, K. S.; Arvidson, R. E.; Neumann, G. A.

    2003-01-01

    The RMS roughness measurements produced by Neumann et al. from Mars Orbiter Laser Altimeter (MOLA) data provide unique information about surface height variations at an effective length scale of < 75 m. Roughness at this scale is important not only for landing site safety considerations, but also for assessment of landscape evolution, which depends on emplacement mechanisms and erosional/depositional processes. Here we present an examination of the global surface roughness map with discussion of terrain types and potential formation and/or alteration mechanisms. Spatially coherent terrain types were identified based on inspection of the roughness map. These terrains were further characterized through analysis of morphology and geology using MOLA topography, MOC wide-angle, and MOC narrow-angle images as well as the geologic maps produced by Scott & Tanaka and Greeley & Guest. All of these data were used to explore potential formation and modification processes.

  18. Surface roughness effects on bidirectional reflectance

    NASA Technical Reports Server (NTRS)

    Smith, T. F.; Hering, R. G.

    1972-01-01

    An experimental study of surface roughness effects on bidirectional reflectance of metallic surfaces is presented. A facility capable of irradiating a sample from normal to grazing incidence and recording plane of incidence bidirectional reflectance measurements was developed. Samples consisting of glass, aluminum alloy, and stainless steel materials were selected for examination. Samples were roughened using standard grinding techniques and coated with a radiatively opaque layer of pure aluminum. Mechanical surface roughness parameters, rms heights and rms slopes, evaluated from digitized surface profile measurements are less than 1.0 micrometers and 0.28, respectively. Rough surface specular, bidirectional, and directional reflectance measurements for selected values of polar angle of incidence and wavelength of incident energy within the spectral range of 1 to 14 micrometers are reported. The Beckmann bidirectional reflectance model is compared with reflectance measurements to establish its usefulness in describing the magnitude and spatial distribution of energy reflected from rough surfaces.

  19. Dynamic Stall Characteristics of Drooped Leading Edge Airfoils

    NASA Technical Reports Server (NTRS)

    Sankar, Lakshmi N.; Sahin, Mehmet; Gopal, Naveen

    2000-01-01

    Helicopters in high-speed forward flight usually experience large regions of dynamic stall over the retreating side of the rotor disk. The rapid variations in the lift and pitching moments associated with the stall process can result in vibratory loads, and can cause fatigue and failure of pitch links. In some instances, the large time lag between the aerodynamic forces and the blade motion can trigger stall flutter. A number of techniques for the alleviation of dynamic stall have been proposed and studied by researchers. Passive and active control techniques have both been explored. Passive techniques include the use of high solidity rotors that reduce the lift coefficients of individual blades, leading edge slots and leading edge slats. Active control techniques include steady and unsteady blowing, and dynamically deformable leading edge (DDLE) airfoils. Considerable amount of experimental and numerical data has been collected on the effectiveness of these concepts. One concept that has not received as much attention is the drooped-leading edge airfoil idea. It has been observed in wind tunnel studies and flight tests that drooped leading edge airfoils can have a milder dynamic stall, with a significantly milder load hysteresis. Drooped leading edge airfoils may not, however, be suitable at other conditions, e.g. in hover, or in transonic flow. Work needs to be done on the analysis and design of drooped leading edge airfoils for efficient operation in a variety of flight regimes (hover, dynamic stall, and transonic flow). One concept that is worthy of investigation is the dynamically drooping airfoil, where the leading edge shape is changed roughly once-per-rev to mitigate the dynamic stall.

  20. Hydrodynamics and Roughness of Irregular Boundaries

    DTIC Science & Technology

    2010-01-01

    morphology data will enable further study on the correlation between roughness and other measurable reef characteristics including coral color, health...on quantitative characterization of substrates and corresponding roughness in coral reef environments along with investigation of AUV capabilities...PC1 and PC2) that account for 74% of the total variance (Figure 2). The spatial patterns for PC1 and PC2 reflect the spatial patterns of sand, coral

  1. Anatomy of the Ocean Surface Roughness

    DTIC Science & Technology

    2007-11-02

    with Theory,” J. Phys. Oceanogr. 13, 1505-1518, 1983. Tang, S. and O.H. Shemdin , “Measurement of High Frequency Waves Using a Wave Follower ,” J...SAR 45 Paul A. Hwang 228-688-4708 Ocean surface roughness can be decomposed into an ambient component, surface wave geometric contribution (the mean...square slope), and breaking wave contribution (the breaking roughness). Only the last two components can be attributed to local wind conditions for

  2. Geoacoustic Physical Modeling: Volume-Roughness Interactions

    DTIC Science & Technology

    2008-09-30

    important break by showing its relationship to the angle of repose , a fundamental feature of granular sediments (such as sands)[Ivakin, 2005...significant considering the fact that the slope of roughness at sub-cm scales at SAX99 site is large and can be close to both angle of repose and...roughness interactions and should be very pronounced at near- and sub-critical grazing angles . For example, the very first theoretical considerations

  3. How supercontinents and superoceans affect seafloor roughness.

    PubMed

    Whittaker, Joanne M; Müller, R Dietmar; Roest, Walter R; Wessel, Paul; Smith, Walter H F

    2008-12-18

    Seafloor roughness varies considerably across the world's ocean basins and is fundamental to controlling the circulation and mixing of heat in the ocean and dissipating eddy kinetic energy. Models derived from analyses of active mid-ocean ridges suggest that ocean floor roughness depends on seafloor spreading rates, with rougher basement forming below a half-spreading rate threshold of 30-35 mm yr(-1) (refs 4, 5), as well as on the local interaction of mid-ocean ridges with mantle plumes or cold-spots. Here we present a global analysis of marine gravity-derived roughness, sediment thickness, seafloor isochrons and palaeo-spreading rates of Cretaceous to Cenozoic ridge flanks. Our analysis reveals that, after eliminating effects related to spreading rate and sediment thickness, residual roughness anomalies of 5-20 mGal remain over large swaths of ocean floor. We found that the roughness as a function of palaeo-spreading directions and isochron orientations indicates that most of the observed excess roughness is not related to spreading obliquity, as this effect is restricted to relatively rare occurrences of very high obliquity angles (>45 degrees ). Cretaceous Atlantic ocean floor, formed over mantle previously overlain by the Pangaea supercontinent, displays anomalously low roughness away from mantle plumes and is independent of spreading rates. We attribute this observation to a sub-Pangaean supercontinental mantle temperature anomaly leading to slightly thicker than normal Late Jurassic and Cretaceous Atlantic crust, reduced brittle fracturing and smoother basement relief. In contrast, ocean crust formed above Pacific superswells, probably reflecting metasomatized lithosphere underlain by mantle at only slightly elevated temperatures, is not associated with basement roughness anomalies. These results highlight a fundamental difference in the nature of large-scale mantle upwellings below supercontinents and superoceans, and their impact on oceanic crustal

  4. Role of surface roughness in superlubricity

    NASA Astrophysics Data System (ADS)

    Tartaglino, U.; Samoilov, V. N.; Persson, B. N. J.

    2006-05-01

    We study the sliding of elastic solids in adhesive contact with flat and rough interfaces. We consider the dependence of the sliding friction on the elastic modulus of the solids. For elastically hard solids with planar surfaces with incommensurate surface structures we observe extremely low friction (superlubricity), which very abruptly increases as the elastic modulus decreases. We show that even a relatively small surface roughness may completely kill the superlubricity state.

  5. Role of surface roughness in superlubricity.

    PubMed

    Tartaglino, U; Samoilov, V N; Persson, B N J

    2006-05-03

    We study the sliding of elastic solids in adhesive contact with flat and rough interfaces. We consider the dependence of the sliding friction on the elastic modulus of the solids. For elastically hard solids with planar surfaces with incommensurate surface structures we observe extremely low friction (superlubricity), which very abruptly increases as the elastic modulus decreases. We show that even a relatively small surface roughness may completely kill the superlubricity state.

  6. Investigating the Surface Roughness of Mercury

    NASA Astrophysics Data System (ADS)

    Susorney, H. C. M.; Barnouin, O. S.; Ernst, C. M.

    2014-12-01

    The Mercury Laser Altimeter (MLA) on the MErcury, Surface, Space ENviorment, GEochemistry, and Ranging (MESSENGER) spacecraft has acquired high-resolution topographic measurements of Mercury's northern hemisphere. These measurements permit the quantification of surface roughness on Mercury over baselines between 500 m and 200 km. In contrast to previous studies of Mercury's surface roughness, which have employed median differential surface slope, we calculate surface roughness as the root mean square (RMS) deviation of the difference in height. If the topography is self-affine or fractal, a power law can be fit to the RMS deviation as a function of baseline length. The exponent of this fit is called the Hurst exponent. This Hurst exponent describes whether or not a surface is self-affine, which occurs when processes produce a surface roughness that is inherently random. The surface roughness of Mercury's northern hemisphere reflects the observed bimodal nature of Mercury: the northern smooth plains have lower roughness values than the rougher heavily cratered terrain and intercrater plains. The relationship between RMS height and baseline length on Mercury shows two fractal sections, one between lengths of 500 m and 1 km, and another between lengths of 1 km and 20 km. We also find that the northern rise is indistinguishable from the surrounding smooth plains across all measured baselines, implying that the rise did not alter its surface topography at the baselines used in this study. Craters that host radar-bright deposits have similar roughness values to craters that do not host such deposits. Finally, fresh crater ejecta within the smooth plains have similar roughness values (particularly at the 1 km baseline) to the intercrater plains, supporting the interpretation that the intercrater plains may result from the modification of volcanic plains via cratering.

  7. Improvement of the edge rotation diagnostic spectrum analysis via simulation.

    PubMed

    Luo, J; Zhuang, G; Cheng, Z F; Zhang, X L; Hou, S Y; Cheng, C

    2014-11-01

    The edge rotation diagnostic (ERD) system has been developed on the Joint Texas Experimental Tokamak to measure the edge toroidal rotation velocity by observing the shifted wavelength of carbon V (C V 227.09 nm). Since the measured spectrum is an integrated result along the viewing line from the plasma core to the edge, a method via simulation has been developed to analyze the ERD spectrum. With the necessary parameters such as C V radiation profile and the ion temperature profile, a local rotation profile at the normalized minor radius of 0.5-1 is obtained.

  8. Improvement of the edge rotation diagnostic spectrum analysis via simulation

    SciTech Connect

    Luo, J.; Zhuang, G. Cheng, Z. F.; Zhang, X. L.; Hou, S. Y.; Cheng, C.

    2014-11-15

    The edge rotation diagnostic (ERD) system has been developed on the Joint Texas Experimental Tokamak to measure the edge toroidal rotation velocity by observing the shifted wavelength of carbon V (C V 227.09 nm). Since the measured spectrum is an integrated result along the viewing line from the plasma core to the edge, a method via simulation has been developed to analyze the ERD spectrum. With the necessary parameters such as C V radiation profile and the ion temperature profile, a local rotation profile at the normalized minor radius of 0.5-1 is obtained.

  9. Automatic road edge detection from Mobile Laser Scanning (MLS)

    NASA Astrophysics Data System (ADS)

    Cabo, Carlos; García-Cortés, Silverio; Menéndez-Díaz, Agustín.; Ordoñez, Celestino

    2016-11-01

    In this article we present an algorithm for automatic road edge detection from MLS (Mobile Laser Scanning) data. The method takes advantage of linear structures derived from MLS point clouds. These lines are extracted from the point cloud and grouped following geometric restrictions. Then, the outlines of the groups are extracted as road edges. Finally, a moving window filter is applied to those points in order to remove outliers and delineate the road edge. The method was tested on an 800m stretch of road, and the results were checked through visual inspection. Correctness and completeness were 99.1% and 97.5%, respectively.

  10. Rough surface reconstruction for ultrasonic NDE simulation

    SciTech Connect

    Choi, Wonjae; Shi, Fan; Lowe, Michael J. S.; Skelton, Elizabeth A.; Craster, Richard V.

    2014-02-18

    The reflection of ultrasound from rough surfaces is an important topic for the NDE of safety-critical components, such as pressure-containing components in power stations. The specular reflection from a rough surface of a defect is normally lower than it would be from a flat surface, so it is typical to apply a safety factor in order that justification cases for inspection planning are conservative. The study of the statistics of the rough surfaces that might be expected in candidate defects according to materials and loading, and the reflections from them, can be useful to develop arguments for realistic safety factors. This paper presents a study of real rough crack surfaces that are representative of the potential defects in pressure-containing power plant. Two-dimensional (area) values of the height of the roughness have been measured and their statistics analysed. Then a means to reconstruct model cases with similar statistics, so as to enable the creation of multiple realistic realizations of the surfaces, has been investigated, using random field theory. Rough surfaces are reconstructed, based on a real surface, and results for these two-dimensional descriptions of the original surface have been compared with those from the conventional model based on a one-dimensional correlation coefficient function. In addition, ultrasonic reflections from them are simulated using a finite element method.

  11. Dentine roughness after different surface treatments.

    PubMed

    Mohsen, M M; Shabka, A A

    1993-01-01

    Surface roughness is one of the most influential criteria affecting the durability and strength of the adhesive restorative materials to the dentine. This study was carried out to investigate the roughness of the dentine surface after some of the modalities proposed for its treatment prior to application of the DBA. Dentine surface roughness of the sixty teeth divided into 12 groups were tested where the dentine surfaces were denuded and were brought to a similar 600 grit surface roughness then different treatments were carried out using H2O2, CO2 gas laser at 30 and 48 J/cm2 energy densities, EDTA and polyacrylic acid treatments. The dentine surface roughness was determined using a profilometer and the results were digitized and plotted using an AUTO-CAD software and Rolland plotter to compare the effects of the different treatments on the dentine surface roughness of the tested samples. Results revealed that the laser treatment left smooth dentine surface and added further evidences to the simplicity and reliability of the conventional use of EDTA and the polyacrylic acid according to the type of adhesive to be used.

  12. Influence of surface roughness on dispersion forces.

    PubMed

    Svetovoy, V B; Palasantzas, G

    2015-02-01

    Surface roughness occurs in a wide variety of processes where it is both difficult to avoid and control. When two bodies are separated by a small distance the roughness starts to play an important role in the interaction between the bodies, their adhesion, and friction. Control of this short-distance interaction is crucial for micro and nanoelectromechanical devices, microfluidics, and for micro and nanotechnology. An important short-distance interaction is the dispersion forces, which are omnipresent due to their quantum origin. These forces between flat bodies can be described by the Lifshitz theory that takes into account the actual optical properties of interacting materials. However, this theory cannot describe rough bodies. The problem is complicated by the nonadditivity of the dispersion forces. Evaluation of the roughness effect becomes extremely difficult when roughness is comparable with the distance between bodies. In this paper we review the current state of the problem. Introduction for non-experts to physical origin of the dispersion forces is given in the paper. Critical experiments demonstrating the nonadditivity of the forces and strong influence of roughness on the interaction between bodies are reviewed. We also describe existing theoretical approaches to the problem. Recent advances in understanding the role of high asperities on the forces at distances close to contact are emphasized. Finally, some opinions about currently unsolved problems are also presented. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Cells preferentially grow on rough substrates.

    PubMed

    Gentile, Francesco; Tirinato, Luca; Battista, Edmondo; Causa, Filippo; Liberale, Carlo; di Fabrizio, Enzo M; Decuzzi, Paolo

    2010-10-01

    Substrate nanotopography affects cell adhesion and proliferation and is fundamental to the rational design of bio-adhesives, to tissue engineering and to the development of assays for in-vitro screening. Cell behavior on rough substrates is still elusive, and the results presented in the open literature remain controversial. Here, the proliferation of cells on electrochemically etched silicon substrates with different roughness and nearly similar surface energy was studied over three days with confocal and atomic force microscopy. The surface profile of the substrates is a self-affine fractal with a roughness R(a) growing with the etching time from approximately 2 to 100 nm and a fractal dimension D ranging between about 2 (nominally flat surface) and 2.6. For four cell types, the number of adhering cells and their proliferation rates exhibited a maximum on moderately rough (R(a) approximately 10-45 nm) nearly Brownian (D approximately 2.5) substrates. The observed cell behavior was satisfactorily interpreted within the theory of adhesion to randomly rough solids. These findings demonstrated the importance of nanogeometry in cell stable adhesion and growth, suggesting that moderately rough substrates with large fractal dimension could selectively boost cell proliferation.

  14. Understanding of Edge Plasmas in Magnetic Fusion Energy Devices

    SciTech Connect

    Rognlien, T

    2004-11-01

    A limited overview is given of the theoretical understanding of edge plasmas in fusion devices. This plasma occupies the thin region between the hot core plasma and material walls in magnetically confinement configurations. The region is often formed by a change in magnetic topology from close magnetic field lines (i.e., the core region) and open field lines that contact material surfaces (i.e., the scrape-off layer [SOL]), with the most common example being magnetically diverted tokamaks. The physics of this region is determined by the interaction of plasma with neutral gas in the presence of plasma turbulence, with impurity radiation being an important component. Recent advances in modeling strong, intermittent micro-turbulent edge-plasma transport is given, and the closely coupled self-consistent evolution of the edge-plasma profiles in tokamaks. In addition, selected new results are given for the characterization of edge-plasmas behavior in the areas of edge-pedestal relaxation and SOL transport via Edge-Localize Modes (ELMs), impurity formation including dust, and magnetic field-line stochasticity in tokamaks.

  15. Are shrubland birds edge specialists?

    PubMed

    Schlossberg, Scott; King, David I

    2008-09-01

    In studies of forest fragmentation, birds of scrubby, early-successional habitats are considered edge specialists. Because these birds are assumed to thrive in fragmented, edge-dominated areas, their landscape ecology has received little attention from ecologists. With populations of shrubland birds declining throughout the eastern United States, the question of whether or not these birds really prefer edge habitats has important conservation implications. We used a meta-analysis to test how edges affect the abundance of shrubland birds in early-successional habitats. We analyzed data for 17 species from seven studies that compared the abundances of birds in the interiors and edges of regenerating clearcuts surrounded by mature forest. The meta-analysis clearly showed that shrubland birds avoid edges. All 17 species tested had higher abundances in patch centers than along edges, and edge effects were significant for 8 of 17 species. The key implication of this result is that small or irregular patches, dominated by edge, are unlikely to provide suitable habitat for shrubland birds. Thus, management for these declining species should involve providing large patches and minimizing edges. These findings demonstrate the importance of testing widely accepted ecological classifications and the need to view landscape ecology from the perspective of non-forest wildlife.

  16. 46 CFR 42.13-25 - Load line mark.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... inches in length and 1 inch in breadth, the upper edge of which passes through the center of the ring... freeboard measured vertically below the upper edge of the deck line (as illustrated in Figure 42.13-25(a...

  17. 46 CFR 42.13-25 - Load line mark.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... inches in length and 1 inch in breadth, the upper edge of which passes through the center of the ring... freeboard measured vertically below the upper edge of the deck line (as illustrated in Figure 42.13-25(a...

  18. Universal emulsion stabilization from the arrested adsorption of rough particles at liquid-liquid interfaces

    PubMed Central

    Zanini, Michele; Marschelke, Claudia; Anachkov, Svetoslav E.; Marini, Emanuele; Synytska, Alla; Isa, Lucio

    2017-01-01

    Surface heterogeneities, including roughness, significantly affect the adsorption, motion and interactions of particles at fluid interfaces. However, a systematic experimental study, linking surface roughness to particle wettability at a microscopic level, is currently missing. Here we synthesize a library of all-silica microparticles with uniform surface chemistry, but tuneable surface roughness and study their spontaneous adsorption at oil–water interfaces. We demonstrate that surface roughness strongly pins the particles' contact lines and arrests their adsorption in long-lived metastable positions, and we directly measure the roughness-induced interface deformations around isolated particles. Pinning imparts tremendous contact angle hysteresis, which can practically invert the particle wettability for sufficient roughness, irrespective of their chemical nature. As a unique consequence, the same rough particles stabilize both water-in-oil and oil-in-water emulsions depending on the phase they are initially dispersed in. These results both shed light on fundamental phenomena concerning particle adsorption at fluid interfaces and indicate future design rules for particle-based emulsifiers. PMID:28589932

  19. Universal emulsion stabilization from the arrested adsorption of rough particles at liquid-liquid interfaces

    NASA Astrophysics Data System (ADS)

    Zanini, Michele; Marschelke, Claudia; Anachkov, Svetoslav E.; Marini, Emanuele; Synytska, Alla; Isa, Lucio

    2017-06-01

    Surface heterogeneities, including roughness, significantly affect the adsorption, motion and interactions of particles at fluid interfaces. However, a systematic experimental study, linking surface roughness to particle wettability at a microscopic level, is currently missing. Here we synthesize a library of all-silica microparticles with uniform surface chemistry, but tuneable surface roughness and study their spontaneous adsorption at oil-water interfaces. We demonstrate that surface roughness strongly pins the particles' contact lines and arrests their adsorption in long-lived metastable positions, and we directly measure the roughness-induced interface deformations around isolated particles. Pinning imparts tremendous contact angle hysteresis, which can practically invert the particle wettability for sufficient roughness, irrespective of their chemical nature. As a unique consequence, the same rough particles stabilize both water-in-oil and oil-in-water emulsions depending on the phase they are initially dispersed in. These results both shed light on fundamental phenomena concerning particle adsorption at fluid interfaces and indicate future design rules for particle-based emulsifiers.

  20. Edge remap for solids

    SciTech Connect

    Kamm, James R.; Love, Edward; Robinson, Allen C.; Young, Joseph G.; Ridzal, Denis

    2013-12-01

    We review the edge element formulation for describing the kinematics of hyperelastic solids. This approach is used to frame the problem of remapping the inverse deformation gradient for Arbitrary Lagrangian-Eulerian (ALE) simulations of solid dynamics. For hyperelastic materials, the stress state is completely determined by the deformation gradient, so remapping this quantity effectively updates the stress state of the material. A method, inspired by the constrained transport remap in electromagnetics, is reviewed, according to which the zero-curl constraint on the inverse deformation gradient is implicitly satisfied. Open issues related to the accuracy of this approach are identified. An optimization-based approach is implemented to enforce positivity of the determinant of the deformation gradient. The efficacy of this approach is illustrated with numerical examples.

  1. On the Edge

    NASA Image and Video Library

    2015-02-04

    In today's image, Mercury's horizon cuts a striking edge against the stark blackness of space. On the right, sunlight harshly brings the landscape into relief while on the left, the surface is shrouded in the darkness of night. This image was acquired as part of MDIS's limb imaging campaign. Once per week, MDIS captures images of Mercury's limb, with an emphasis on imaging the southern hemisphere limb. These limb images provide information about Mercury's shape and complement measurements of topography made by the Mercury Laser Altimeter (MLA) of Mercury's northern hemisphere. Date acquired: January 20, 2015 Image Mission Elapsed Time (MET): 64084239 Image ID: 7831084 Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS) WAC filter: 7 (748 nanometers) Center Latitude: -54.45° Center Longitude: 90.52° E Center Resolution: 401 meters/pixel http://photojournal.jpl.nasa.gov/catalog/PIA19192

  2. How to make a soft, rough surface transparent

    NASA Astrophysics Data System (ADS)

    Helseth, L. E.

    2017-09-01

    A transparent elastomer is made opaque by making one of its surfaces rough. By squeezing the rough surface against a piece of glass, the roughness is smoothed out and the elastomer becomes transparent.

  3. EM Bias-Correction for Ice Thickness and Surface Roughness Retrievals over Rough Deformed Sea Ice

    NASA Astrophysics Data System (ADS)

    Li, L.; Gaiser, P. W.; Allard, R.; Posey, P. G.; Hebert, D. A.; Richter-Menge, J.; Polashenski, C. M.

    2016-12-01

    The very rough ridge sea ice accounts for significant percentage of total ice areas and even larger percentage of total volume. The commonly used Radar altimeter surface detection techniques are empirical in nature and work well only over level/smooth sea ice. Rough sea ice surfaces can modify the return waveforms, resulting in significant Electromagnetic (EM) bias in the estimated surface elevations, and thus large errors in the ice thickness retrievals. To understand and quantify such sea ice surface roughness effects, a combined EM rough surface and volume scattering model was developed to simulate radar returns from the rough sea ice `layer cake' structure. A waveform matching technique was also developed to fit observed waveforms to a physically-based waveform model and subsequently correct the roughness induced EM bias in the estimated freeboard. This new EM Bias Corrected (EMBC) algorithm was able to better retrieve surface elevations and estimate the surface roughness parameter simultaneously. In situ data from multi-instrument airborne and ground campaigns were used to validate the ice thickness and surface roughness retrievals. For the surface roughness retrievals, we applied this EMBC algorithm to co-incident LiDAR/Radar measurements collected during a Cryosat-2 under-flight by the NASA IceBridge missions. Results show that not only does the waveform model fit very well to the measured radar waveform, but also the roughness parameters derived independently from the LiDAR and radar data agree very well for both level and deformed sea ice. For sea ice thickness retrievals, validation based on in-situ data from the coordinated CRREL/NRL field campaign demonstrates that the physically-based EMBC algorithm performs fundamentally better than the empirical algorithm over very rough deformed sea ice, suggesting that sea ice surface roughness effects can be modeled and corrected based solely on the radar return waveforms.

  4. Rough mill simulator version 3.0: an analysis tool for refining rough mill operations

    Treesearch

    Edward Thomas; Joel Weiss

    2006-01-01

    ROMI-3 is a rough mill computer simulation package designed to be used by both rip-first and chop-first rough mill operators and researchers. ROMI-3 allows users to model and examine the complex relationships among cutting bill, lumber grade mix, processing options, and their impact on rough mill yield and efficiency. Integrated into the ROMI-3 software is a new least-...

  5. Sidewall roughness measurement inside photonic crystal holes by atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Strasser, P.; Robin, F.; Carlström, C. F.; Wüest, R.; Kappeler, R.; Jäckel, H.

    2007-10-01

    We present a measurement technique to quantify sidewall roughness inside planar photonic crystal (PhC) holes. Atomic force microscopy is used to scan hole cross-section profiles. By fitting a circle onto each scan line and subtracting this circle from the measurement data, a quantitative value for the deviation from the ideal cylindrical hole shape is extracted. We investigate the sidewall roughness of InP-based PhC holes depending on the nitrogen content of the semiconductor etching plasma. The existence of a trade-off between hole undercut and surface roughness by optimizing the flux of nitrogen during the plasma etching of the PhC holes is confirmed. We further quantify with this technique the influence of the direct-writing of octagons instead of circles by electron-beam lithography on the measured roughness.

  6. Edge phonons in black phosphorus

    PubMed Central

    Ribeiro, H. B.; Villegas, C. E. P.; Bahamon, D. A.; Muraca, D.; Castro Neto, A. H.; de Souza, E. A. T.; Rocha, A. R.; Pimenta, M. A.; de Matos, C. J. S.

    2016-01-01

    Black phosphorus has recently emerged as a new layered crystal that, due to its peculiar and anisotropic crystalline and electronic band structures, may have important applications in electronics, optoelectronics and photonics. Despite the fact that the edges of layered crystals host a range of singular properties whose characterization and exploitation are of utmost importance for device development, the edges of black phosphorus remain poorly characterized. In this work, the atomic structure and behaviour of phonons near different black phosphorus edges are experimentally and theoretically studied using Raman spectroscopy and density functional theory calculations. Polarized Raman results show the appearance of new modes at the edges of the sample, and their spectra depend on the atomic structure of the edges (zigzag or armchair). Theoretical simulations confirm that the new modes are due to edge phonon states that are forbidden in the bulk, and originated from the lattice termination rearrangements. PMID:27412813

  7. Edge phonons in black phosphorus

    NASA Astrophysics Data System (ADS)

    Ribeiro, H. B.; Villegas, C. E. P.; Bahamon, D. A.; Muraca, D.; Castro Neto, A. H.; de Souza, E. A. T.; Rocha, A. R.; Pimenta, M. A.; de Matos, C. J. S.

    2016-07-01

    Black phosphorus has recently emerged as a new layered crystal that, due to its peculiar and anisotropic crystalline and electronic band structures, may have important applications in electronics, optoelectronics and photonics. Despite the fact that the edges of layered crystals host a range of singular properties whose characterization and exploitation are of utmost importance for device development, the edges of black phosphorus remain poorly characterized. In this work, the atomic structure and behaviour of phonons near different black phosphorus edges are experimentally and theoretically studied using Raman spectroscopy and density functional theory calculations. Polarized Raman results show the appearance of new modes at the edges of the sample, and their spectra depend on the atomic structure of the edges (zigzag or armchair). Theoretical simulations confirm that the new modes are due to edge phonon states that are forbidden in the bulk, and originated from the lattice termination rearrangements.

  8. Measurement of roughness based on the Talbot effect in reflection from rough surfaces.

    PubMed

    Dashtdar, Masoomeh; Mohammadzade, Ali; Hosseini-Saber, S Mohammad-Ali

    2015-06-01

    In the present work, the Talbot effect of a square grating is analyzed when light is reflected from a rough surface. It is shown theoretically that the scattered light intensity in the Fresnel diffraction limit depends on statistical properties of the rough surface, the angle of incidence of the light, the grating period, and a geometric coefficient, related to the ratio of distance of the rough surface and the observation plane from the grating. At Talbot distances of the grating, the surface height difference function, in terms of multiplication of the Talbot number, the grating period, and the geometric coefficient is the modulation transfer function (MTF) of the scattering in reflection from the rough surface. If the argument of the height difference function is larger than twice the surface correlation length, the height difference function is constant for different spatial frequencies. Therefore, the square wave is reproduced with smaller contrast. The surface roughness can be obtained by measuring the contrast at different incident angles. It is also shown that the contrast measurements in both reflection and transmission, provide the refractive index of transparent samples with a rough surface. In experimental studies, the roughness of three metal standard rough surfaces are determined at different angles of incidence. Also, the refractive index of a sheet glass with a rough surface is obtained. The results are quite consistent.

  9. Robust design optimization method for centrifugal impellers under surface roughness uncertainties due to blade fouling

    NASA Astrophysics Data System (ADS)

    Ju, Yaping; Zhang, Chuhua

    2016-03-01

    Blade fouling has been proved to be a great threat to compressor performance in operating stage. The current researches on fouling-induced performance degradations of centrifugal compressors are based mainly on simplified roughness models without taking into account the realistic factors such as spatial non-uniformity and randomness of the fouling-induced surface roughness. Moreover, little attention has been paid to the robust design optimization of centrifugal compressor impellers with considerations of blade fouling. In this paper, a multi-objective robust design optimization method is developed for centrifugal impellers under surface roughness uncertainties due to blade fouling. A three-dimensional surface roughness map is proposed to describe the nonuniformity and randomness of realistic fouling accumulations on blades. To lower computational cost in robust design optimization, the support vector regression (SVR) metamodel is combined with the Monte Carlo simulation (MCS) method to conduct the uncertainty analysis of fouled impeller performance. The analyzed results show that the critical fouled region associated with impeller performance degradations lies at the leading edge of blade tip. The SVR metamodel has been proved to be an efficient and accurate means in the detection of impeller performance variations caused by roughness uncertainties. After design optimization, the robust optimal design is found to be more efficient and less sensitive to fouling uncertainties while maintaining good impeller performance in the clean condition. This research proposes a systematic design optimization method for centrifugal compressors with considerations of blade fouling, providing a practical guidance to the design of advanced centrifugal compressors.

  10. Transition Experiments on Large Bluntness Cones with Distributed Roughness in Hypersonic Flight

    NASA Technical Reports Server (NTRS)

    Reda, Daniel. C.; Wilder, Michael C.; Prabhu, Dinesh K.

    2012-01-01

    Large bluntness cones with smooth nosetips and roughened frusta were flown in the NASA Ames hypersonic ballistic range at a Mach number of 10 through quiescent air environments. Global surface intensity (temperature) distributions were optically measured and analyzed to determine transition onset and progression over the roughened surface. Real-gas Navier-Stokes calculations of model flowfields, including laminar boundary layer development in these flowfields, were conducted to predict values of key dimensionless parameters used to correlate transition on such configurations in hypersonic flow. For these large bluntness cases, predicted axial distributions of the roughness Reynolds number showed (for each specified freestream pressure) that this parameter was a maximum at the physical beginning of the roughened zone and decreased with increasing run length along the roughened surface. Roughness-induced transition occurred downstream of this maximum roughness Reynolds number location, and progressed upstream towards the beginning of the roughened zone as freestream pressure was systematically increased. Roughness elements encountered at the upstream edge of the roughened frusta thus acted like a finite-extent trip array, consistent with published results concerning the tripping effectiveness of roughness bands placed on otherwise smooth surfaces.

  11. Effects of Yb:KYW thin-disk femtosecond laser ablation on enamel surface roughness

    NASA Astrophysics Data System (ADS)

    Liu, Jing; Sun, Yuchun; Wang, Yong; Lü, Peijun

    2014-07-01

    This study aimed to quantitatively evaluate the surface roughness of enamel following ablation with a Yb:KYW thin-disk femtosecond pulsed laser at different fluences (F), scanning speeds and scanning line spacings. Thirty human extracted teeth were sectioned into crowns and roots along the cementum-enamel junction, and then the crowns were cut longitudinally into sheets about 1.5 mm thick. The samples were randomly divided into ten groups (n=3). Samples of groups 1-8 were irradiated with a femtosecond pulsed laser. These enamel samples were fixed on a stage at focus plane, and a laser beam irradiated onto the samples through a galvanometric scanning system, with which rectangular movement could be achieved. Samples of groups 9 and 10 were prepared with grinding instruments. Following ablation and preparation, the samples were examined for surface roughness with a three-dimensional laser profile measurement microscope. The results showed that scanning speed and scanning line spacing had little influence on the surface roughness of femtosecond pulsed laser-ablated enamel, except when F=4 J/cm2. When a lower fluence was used, the enamel surface roughness was higher, and vice versa. This study showed that various laser fluences, scanning speeds and scanning line spacings can affect and alter enamel surface roughness. Therefore, adequate parameters should be chosen to achieve the proper therapeutic benefits.

  12. Geometries for roughness shapes in laminar flow

    NASA Technical Reports Server (NTRS)

    Holmes, Bruce J. (Inventor); Martin, Glenn L. (Inventor); Domack, Christopher S. (Inventor); Obara, Clifford J. (Inventor); Hassan, Ahmed A. (Inventor)

    1986-01-01

    A passive interface mechanism between upper and lower skin structures, and a leading edge structure of a laminar flow airfoil is described. The interface mechanism takes many shapes. All are designed to be different than the sharp orthogonal arrangement prevalent in the prior art. The shapes of the interface structures are generally of two types: steps away from the centerline of the airfoil with a sloping surface directed toward the trailing edge and, the other design has a gap before the sloping surface. By properly shaping the step, the critical step height is increased by more than 50% over the orthogonal edged step.

  13. The Facilitator's Edge: Group Sessions for Edge-ucators.

    ERIC Educational Resources Information Center

    Handcock, Helen

    The Facilitator's Edge is a workshop series based on the life/work messages of The Edge magazine. The workshops are deigned to help educators, youth workers, and their career practitioners facilitate conscious career building. This manual consists of five group sessions, each focusing on a different career-building theme. "Megatrends and…

  14. The Facilitator's Edge: Group Sessions for Edge-ucators.

    ERIC Educational Resources Information Center

    Handcock, Helen

    The Facilitator's Edge is a workshop series based on the life/work messages of The Edge magazine. The workshops are deigned to help educators, youth workers, and their career practitioners facilitate conscious career building. This manual consists of five group sessions, each focusing on a different career-building theme. "Megatrends and…

  15. Comparison of Predicted and Measured Turbine Vane Rough Surface Heat Transfer

    NASA Technical Reports Server (NTRS)

    Boyle, R. J.; Spuckler, C. M.; Lucci, B. L.

    2000-01-01

    The proposed paper compares predicted turbine vane heat transfer for a rough surface over a wide range of test conditions with experimental data. Predictions were made for the entire vane surface. However, measurements were made only over the suction surface of the vane, and the leading edge region of the pressure surface. Comparisons are shown for a wide range of test conditions. Inlet pressures varied between 3 and 15 psia, and exit Mach numbers ranged between 0.3 and 0.9. Thus, while a single roughened vane was used for the tests, the effective rougness,(k(sup +)), varied by more than a factor of ten. Results were obtained for freestream turbulence levels of 1 and 10%. Heat transfer predictions were obtained using the Navier-Stokes computer code RVCQ3D. Two turbulence models, suitable for rough surface analysis, are incorporated in this code. The Cebeci-Chang roughness model is part of the algebraic turbulence model. The k-omega turbulence model accounts for the effect of roughness in the application of the boundary condition. Roughness causes turbulent flow over the vane surface. Even after accounting for transition, surface roughness significantly increased heat transfer compared to a smooth surface. The k-omega results agreed better with the data than the Cebeci-Chang model. However, the low Reynolds number k-omega model did not accurately account for roughness when the freestream turbulence level was low. The high Reynolds number version of this model was more suitable when the freestream turbulence was low.

  16. Brightness versus roughness: a multiscale approach

    NASA Astrophysics Data System (ADS)

    Bigerelle, M.; Marteau, J.; Paulin, C.

    2015-03-01

    A link between roughness and brightness is sought for brass specimens that were superfinished, sandblasted and brushed. Only the blasting conditions are varied in order to get different roughness and brightness. First, a relation between roughness and brightness is sought for specimens that were superfinished and sandblasted. The best relation is obtained using the mean height of the motifs, calculated using a low-pass filter and cut-off length equal to 30 μm, with a logarithmic-logarithmic model. Then, the same type of relation is determined after superfinishing sandblasting and brushing. The core material volume Vmc, computed using a high-pass filter with a cut-off length of 60 μm and a linear-logarithmic relationship, gives the best results. A relation between roughness and brightness that is common to both the pre-brushing state and post-brushing state is identified: the best roughness parameter is the arithmetic mean deviation Sa using a high-pass filter with a cut-off of 15 μm, with a logarithmic-logarithmic relationship. Finally, it is shown that the use of these filtering conditions enables us to verify the model of Beckmann and Spizzichino for the examined specimens. This scale corresponds to the end of the fractal regime and is close to the end of the signal correlation.

  17. Suppression of intrinsic roughness in encapsulated graphene

    NASA Astrophysics Data System (ADS)

    Thomsen, Joachim Dahl; Gunst, Tue; Gregersen, Søren Schou; Gammelgaard, Lene; Jessen, Bjarke Sørensen; Mackenzie, David M. A.; Watanabe, Kenji; Taniguchi, Takashi; Bøggild, Peter; Booth, Timothy J.

    2017-07-01

    Roughness in graphene is known to contribute to scattering effects which lower carrier mobility. Encapsulating graphene in hexagonal boron nitride (hBN) leads to a significant reduction in roughness and has become the de facto standard method for producing high-quality graphene devices. We have fabricated graphene samples encapsulated by hBN that are suspended over apertures in a substrate and used noncontact electron diffraction measurements in a transmission electron microscope to measure the roughness of encapsulated graphene inside such structures. We furthermore compare the roughness of these samples to suspended bare graphene and suspended graphene on hBN. The suspended heterostructures display a root mean square (rms) roughness down to 12 pm, considerably less than that previously reported for both suspended graphene and graphene on any substrate and identical within experimental error to the rms vibrational amplitudes of carbon atoms in bulk graphite. Our first-principles calculations of the phonon bands in graphene/hBN heterostructures show that the flexural acoustic phonon mode is localized predominantly in the hBN layer. Consequently, the flexural displacement of the atoms in the graphene layer is strongly suppressed when it is supported by hBN, and this effect increases when graphene is fully encapsulated.

  18. Hypersonic Viscous Flow Over Large Roughness Elements

    NASA Technical Reports Server (NTRS)

    Chang, Chau-Lyan; Choudhari, Meelan M.

    2009-01-01

    Viscous flow over discrete or distributed surface roughness has great implications for hypersonic flight due to aerothermodynamic considerations related to laminar-turbulent transition. Current prediction capability is greatly hampered by the limited knowledge base for such flows. To help fill that gap, numerical computations are used to investigate the intricate flow physics involved. An unstructured mesh, compressible Navier-Stokes code based on the space-time conservation element, solution element (CESE) method is used to perform time-accurate Navier-Stokes calculations for two roughness shapes investigated in wind tunnel experiments at NASA Langley Research Center. It was found through 2D parametric study that at subcritical Reynolds numbers, spontaneous absolute instability accompanying by sustained vortex shedding downstream of the roughness is likely to take place at subsonic free-stream conditions. On the other hand, convective instability may be the dominant mechanism for supersonic boundary layers. Three-dimensional calculations for both a rectangular and a cylindrical roughness element at post-shock Mach numbers of 4.1 and 6.5 also confirm that no self-sustained vortex generation from the top face of the roughness is observed, despite the presence of flow unsteadiness for the smaller post-shock Mach number case.

  19. Edge-edge interactions in stacked graphene nanoplatelets

    SciTech Connect

    Cruz Silva, Eduardo; Terrones Maldonado, Humberto; Terrones Maldonado, Mauricio; Jia, Xiaoting; Sumpter, Bobby G; Dresselhaus, M; Meunier, V.

    2013-01-01

    High-resolution transmission electron microscopy (HRTEM) studies show the dynamics of small graphene platelets on larger graphene layers. The platelets move nearly freely to eventually lock in at well-defined positions close to the edges of the larger underlying graphene sheet. While such movement is driven by a shallow potential energy surface described by an interplane interaction, the lock-in position occurs by via edge-edge interactions of the platelet and the graphene surface located underneath. Here we quantitatively study this behavior using van der Waals density functional calculations. Local interactions at the open edges are found to dictate stacking configurations that are different from Bernal (AB) stacking. These stacking configurations are known to be otherwise absent in edge-free two-dimensional (2D) graphene. The results explain the experimentally observed platelet dynamics and provide a detailed account of the new electronic properties of these combined systems.

  20. Surface topography and roughness of high-speed milled AlMn1Cu

    NASA Astrophysics Data System (ADS)

    Wang, Zhenhua; Yuan, Juntang; Yin, Zengbin; Hu, Xiaoqiu

    2016-10-01

    The aluminum alloy AlMn1Cu has been broadly applied for functional parts production because of its good properties. But few researches about the machining mechanism and the surface roughness were reported. The high-speed milling experiments are carried out in order to improve the machining quality and reveal the machining mechanism. The typical topography features of machined surface are observed by scan electron microscope(SEM). The results show that the milled surface topography is mainly characterized by the plastic shearing deformation surface and material piling zone. The material flows plastically along the end cutting edge of the flat-end milling tool and meanwhile is extruded by the end cutting edge, resulting in that materials partly adhere to the machined surface and form the material piling zone. As the depth of cut and the feed per tooth increase, the plastic flow of materials is strengthened and the machined surface becomes rougher. However, as the cutting speed increases, the plastic flow of materials is weakened and the milled surface becomes smoother. The cutting parameters (e.g. cutting speed, feed per tooth and depth of cut) influencing the surface roughness are analyzed. It can be concluded that the roughness of the machined surface formed by the end cutting edge is less than that by the cylindrical cutting edge when a cylindrical flat-end mill tool is used for milling. The proposed research provides the typical topography features of machined surface of the anti-rust aluminum alloy AlMn1Cu in high speed milling.

  1. Viscosity in the edge of tokamak plasmas

    SciTech Connect

    Stacey, W.M.

    1993-05-01

    A fluid representation of viscosity has been incorporated into a set of fluid equations that are maximally ordered in the ``short-radial-gradient-scale-length`` (srgsl) ordering that is appropriate for the edge of tokamak plasmas. The srgsl ordering raises viscous drifts and other viscous terms to leading order and fundamentally alters the character of the fluid equations. A leasing order viscous drift is identified. Viscous-driven radial particle and energy fluxes in the scrape-off layer and divertor channel are estimated to have an order unity effect in reducing radial peaking of energy fluxes transported along the field lines to divertor collector plates.

  2. Viscosity in the edge of tokamak plasmas

    NASA Astrophysics Data System (ADS)

    Stacey, W. M.

    1993-05-01

    A fluid representation of viscosity has been incorporated into a set of fluid equations that are maximally ordered in the 'short radial gradient scale length' (srgsl) ordering that is appropriate for the edge of tokamak plasmas. The srgsl ordering raises viscous drifts and other viscous terms to leading order and fundamentally alters the character of the fluid equations. A leasing order viscous drift is identified. Viscous-driven radial particle and energy fluxes in the scrape-off layer and divertor channel are estimated to have an order unity effect in reducing radial peaking of energy fluxes transported along the field lines to divertor collector plates.

  3. Optical Roughness Measurements Of Industrial Surfaces

    NASA Astrophysics Data System (ADS)

    Gilsinn, David; Vorburger, Theodore; Cao, Lin-Xiang; Giauque, Charles; Scire, Fredric; Teague, E. Clayton

    1986-10-01

    This paper reviews our efforts to develop the theory and instrumentation needed to measure surface roughness of manufactured surfaces by optical scattering methods. We are addressing three key problems: developing a valid and sufficient optical scattering theory for this roughness range, applying appropriate mathematical inversion techniques so that practical roughness parameters can be calculated from scattering distributions, and finally evaluating a compact commercial instrument for a wide variety of problems. Recent results from our group suggest that the simple phase screen approximation model of optical scattering validly describes light scattering from machined metal surfaces with a predominant surface lay in the 0.01 pm R to 3.0 pm R range. A model for scattering in the entire farr-field hemisphere and obsera vations on our r approach to the inverse problem is given.

  4. The Edge of Jupiter

    NASA Image and Video Library

    2017-04-19

    This enhanced color Jupiter image, taken by the JunoCam imager on NASA's Juno spacecraft, showcases several interesting features on the apparent edge (limb) of the planet. Prior to Juno's fifth flyby over Jupiter's mysterious cloud tops, members of the public voted on which targets JunoCam should image. This picture captures not only a fascinating variety of textures in Jupiter's atmosphere, it also features three specific points of interest: "String of Pearls," "Between the Pearls," and "An Interesting Band Point." Also visible is what's known as the STB Spectre, a feature in Jupiter's South Temperate Belt where multiple atmospheric conditions appear to collide. JunoCam images of Jupiter sometimes appear to have an odd shape. This is because the Juno spacecraft is so close to Jupiter that it cannot capture the entire illuminated area in one image -- the sides get cut off. Juno acquired this image on March 27, 2017, at 2:12 a.m. PDT (5:12 a.m. EDT), as the spacecraft performed a close flyby of Jupiter. When the image was taken, the spacecraft was about 12,400 miles (20,000 kilometers) from the planet. This enhanced color image was created by citizen scientist Bjorn Jonsson. https://photojournal.jpl.nasa.gov/catalog/PIA21389

  5. Widely tunable edge emitters

    NASA Astrophysics Data System (ADS)

    Sarlet, Gert; Wesstrom, Jan-Olof; Rigole, Pierre-Jean; Broberg, Bjoern

    2001-11-01

    We will present the current state-of-the-art in widely tunable edge emitting lasers for WDM applications. Typical applications for a tunable laser will be discussed, and the different types of tunable lasers available today will be compared with respect to the requirements posed by these applications. We will focus on the DBR-type tunable lasers - DBR, SG-DBR and GCSR - which at present seem to be the only tunable lasers mature enough for real-life applications. Their main advantages are that they are all monolithic, with no moving parts, and can be switched from one frequency to the other very rapidly since the tuning is based on carrier injection and not on thermal or mechanical changes. We will briefly discuss the working principle of each of these devices, and present typical performance characteristics. From a manufacturing point of view, rapid characterization of the lasers is crucial; therefore an overview will be given of different characterization schemes that have recently been proposed. For the end user, reliability is the prime issue. We will show results of degradation studies on these lasers and outline how the control electronics that drive the laser can compensate for any frequency drift. Finally, we will also discuss the impact of the requirement for rapid frequency switching on the design of the control electronics.

  6. Wing Leading Edge Debris Analysis

    NASA Technical Reports Server (NTRS)

    Shah, Sandeep; Jerman, Gregory

    2004-01-01

    This is a slide presentation showing the Left Wing Leading Edge (WLE) heat damage observations: Heavy "slag" deposits on select RCC panels. Eroded and knife-edged RCC rib sections. Excessive overheating and slumping of carrier panel tiles. Missing or molten attachment bolts but intact bushing. Deposit mainly on "inside" RCC panel. Deposit on some fractured RCC surface

  7. Rock Segmentation through Edge Regrouping

    NASA Technical Reports Server (NTRS)

    Burl, Michael

    2008-01-01

    Rockster is an algorithm that automatically identifies the locations and boundaries of rocks imaged by the rover hazard cameras (hazcams), navigation cameras (navcams), or panoramic cameras (pancams). The software uses edge detection and edge regrouping to identify closed contours that separate the rocks from the background.

  8. Improved Edge Performance in MRF

    NASA Technical Reports Server (NTRS)

    Shorey, Aric; Jones, Andrew; Durnas, Paul; Tricard, Marc

    2004-01-01

    The fabrication of large segmented optics requires a polishing process that can correct the figure of a surface to within a short distance from its edges-typically, a few millimeters. The work here is to develop QED's Magnetorheological Finishing (MRF) precision polishing process to minimize residual edge effects.

  9. Slip due to surface roughness for a Newtonian liquid in a viscous microscale disk pump

    NASA Astrophysics Data System (ADS)

    Ligrani, Phil; Blanchard, Danny; Gale, Bruce

    2010-05-01

    In the present study, hydrophobic roughness is used to induce near-wall slip in a single rotating-disk micropump operating with Newtonian water. The amount of induced slip is altered by employing different sizes of surface roughness on the rotating disk. The magnitudes of slip length and slip velocities increase as the average size of the surface roughness becomes larger. In the present study, increased slip magnitudes from roughness are then associated with reduced pressure rise through the pump and lower radial-line-averaged shear stress magnitudes (determined within slip planes). Such shear stress and pressure rise variations are similar to those which would be present if the slip is induced by the intermolecular interactions which are associated with near-wall microscale effects. The present slip-roughness effects are quantified experimentally over rotational speeds from 50 to 1200 rpm, pressure increases from 0 to 312 kPa, net flow rates of 0-100 μl/min, and fluid chamber heights from 6.85 to 29.2 μm. Verification is provided by comparisons with analytic results determined from the rotating Couette flow forms of the Navier-Stokes equations, with different disk rotational speeds, disk roughness levels, and fluid chamber heights. These data show that slip length magnitudes show significant dependence on radial-line-averaged shear stress for average disk roughness heights of 404 and 770 nm. These slip length data additionally show a high degree of organization when normalized using by either the average roughness height or the fluid chamber height. For the latter case, such behavior provides evidence that the flow over a significant portion of the passage height is affected by the roughness, and near-wall slip velocities, especially when the average roughness height amounts to 11% of the h =6.86 μm passage height of the channel. Such scaling of the disk slip length bdisk with fluid chamber height h is consistent with d-type roughness scaling in macroscale

  10. Pattern characterization and connectivity analysis for edge feature extraction

    NASA Astrophysics Data System (ADS)

    Jiang, Bo

    2015-07-01

    The purpose of detecting sharp changes in image brightness is to capture important events and changes in properties of the world. The accuracy of edge detection methods in image processing determines the eventual success or failure of computerized analysis procedures which follow the initial edge detection determinations such as object recognition. Generally, edge detectors have been designed to capture simple ideal step functions in image data, but real image signal discontinuities deviate from this ideal form. Another three types of deviations from the step function which relate to real distortions occurring in natural images are examined according to their characteristics. These types are impulse, ramp, and sigmoid functions which respectively represent narrow line signals, simplified blur effects, and more accurate blur modeling. General rules for edge pattern characterization based upon the classification of edge types into four categories-ramp, impulse, step, and sigmoid (RISS) are developed from this analysis. Additionally, the proposed algorithm performs connectivity analysis on edge map to ensure that small, disconnected edges are removed. The performance analysis on experiments supports that the proposed edge detection algorithm with edge pattern analysis and characterization does lead to more effective edge detection and localization with improved accuracies. To expand the proposed algorithm into real-time applications, a parallel implementation on a graphics processing unit (GPU) is presented in this paper. For the various configurations in our test, the GPU implementation shows a scalable speedup as the resolution of an image increases. We also achieved 14 frames per second in real-time processing (1280×720).

  11. General laws of X-ray reflection from rough surfaces: II. Conformal roughness

    NASA Astrophysics Data System (ADS)

    Kozhevnikov, I. V.

    2012-07-01

    Is shown that, if the expansions of the Debye-Waller formulas for the reflection and total scattering coefficients in the roughness height σ are limited to terms of order σ2, these expressions are valid for any layered inhomogeneous medium with conformal (depth-periodic) roughness and for any distribution function of the roughness heights if the roughness correlation length along the surface is sufficiently large. The advantages of measuring the total reflection coefficient, which characterizes the total intensity of radiation (both specularly reflected and diffusively scattered) directed by a rough surface back into vacuum, for solving the inverse problem of X-ray reflectometry (i.e., the reconstruction of the permittivity profile from a measured reflection curve) are discussed.

  12. Roughness Perception of Haptically Displayed Fractal Surfaces

    NASA Technical Reports Server (NTRS)

    Costa, Michael A.; Cutkosky, Mark R.; Lau, Sonie (Technical Monitor)

    2000-01-01

    Surface profiles were generated by a fractal algorithm and haptically rendered on a force feedback joystick, Subjects were asked to use the joystick to explore pairs of surfaces and report to the experimenter which of the surfaces they felt was rougher. Surfaces were characterized by their root mean square (RMS) amplitude and their fractal dimension. The most important factor affecting the perceived roughness of the fractal surfaces was the RMS amplitude of the surface. When comparing surfaces of fractal dimension 1.2-1.35 it was found that the fractal dimension was negatively correlated with perceived roughness.

  13. Rough and Steep Terrain Lunar Surface Mobility

    NASA Technical Reports Server (NTRS)

    Wilcox, Brian

    2005-01-01

    In the summer of 2004, the NASA Exploration Systems Mission Directorate conducted an open call for projects relevant to human and robotic exploration of the Earth-Moon and Mars systems. A project entitled 'Rough and Steep Terrain Lunar Surface Mobility' was submitted by JPL and accepted by NASA. The principal investigator of this project describes the robotic vehicle being developed for this effort, which includes six 'wheels-on-legs' so that it can roll efficiently on relatively smooth terrain but walk (using locked wheels as footpads) when "the going gets rough".

  14. Roughness in lattice ordered effect algebras.

    PubMed

    Xin, Xiao Long; Hua, Xiu Juan; Zhu, Xi

    2014-01-01

    Many authors have studied roughness on various algebraic systems. In this paper, we consider a lattice ordered effect algebra and discuss its roughness in this context. Moreover, we introduce the notions of the interior and the closure of a subset and give some of their properties in effect algebras. Finally, we use a Riesz ideal induced congruence and define a function e(a, b) in a lattice ordered effect algebra E and build a relationship between it and congruence classes. Then we study some properties about approximation of lattice ordered effect algebras.

  15. Roughness in Lattice Ordered Effect Algebras

    PubMed Central

    Xin, Xiao Long; Hua, Xiu Juan; Zhu, Xi

    2014-01-01

    Many authors have studied roughness on various algebraic systems. In this paper, we consider a lattice ordered effect algebra and discuss its roughness in this context. Moreover, we introduce the notions of the interior and the closure of a subset and give some of their properties in effect algebras. Finally, we use a Riesz ideal induced congruence and define a function e(a, b) in a lattice ordered effect algebra E and build a relationship between it and congruence classes. Then we study some properties about approximation of lattice ordered effect algebras. PMID:25170523

  16. Hailstone classifier based on Rough Set Theory

    NASA Astrophysics Data System (ADS)

    Wan, Huisong; Jiang, Shuming; Wei, Zhiqiang; Li, Jian; Li, Fengjiao

    2017-09-01

    The Rough Set Theory was used for the construction of the hailstone classifier. Firstly, the database of the radar image feature was constructed. It included transforming the base data reflected by the Doppler radar into the bitmap format which can be seen. Then through the image processing, the color, texture, shape and other dimensional features should be extracted and saved as the characteristic database to provide data support for the follow-up work. Secondly, Through the Rough Set Theory, a machine for hailstone classifications can be built to achieve the hailstone samples’ auto-classification.

  17. ROUGHNESS LENGTHS FOR THE SAVANNAH RIVER SITE

    SciTech Connect

    Hunter, C.

    2012-03-28

    Surface roughness values for the areas surrounding the H, D and N-Area meteorological towers were computed from archived 2010 meteorological data. These 15-minute-averaged data were measured with cup anemometers and bidirectional wind vanes (bivanes) 61 m above the surface. The results of the roughness calculation using the standard deviation of elevation angle {sigma}{sub E}, and applying the simple formula based on tree canopy height, gave consistent estimates for roughness around the H-Area tower in the range of 1.76 to 1.86 m (95% confidence interval) with a mean value of 1.81 m. Application of the {sigma}{sub E} method for the 61-m level at D and N-Areas gave mean values of 1.71 and 1.81 with confidence ranges of 1.62-1.81 and 1.73-1.88 meters, respectively. Roughness results are azimuth dependent, and thus are presented as averages over compass sectors spanning 22.5 degrees. Calculated values were compared to other methods of determining roughness, including the standard deviation of the azimuth direction, {sigma}{sub A}, and standard deviation of the wind speed, {sigma}{sub U}. Additional data was obtained from a sonic anemometer at 61-m on the H-Area tower during a period of a few weeks in 2010. Results from the sonic anemometer support our use of {sigma}{sub E} to calculate roughness. Based on the H-Area tower results, a surface roughness of 1.8 m using is recommended for use in dispersion modeling applications that consider the impacts of a contaminant release to individuals along the Site boundary. The canopy surrounding the H-Area tower is relatively uniform (i.e., little variance in roughness by upwind direction), and data supplied by the U.S. Forest Service at Savannah River show that the canopy height and composition surrounding the H-Area tower is reasonably representative of forested areas throughout the SRS reservation. For dispersion modeling analyses requiring assessments of a co-located worker within the respective operations area, recommended

  18. Evaluation of Dry, Rough Vacuum Pumps

    NASA Technical Reports Server (NTRS)

    Hunter, Brian

    2006-01-01

    This document provides information on the testing and evaluation of thirteen dry rough vacuum pumps of various designs and from various manufacturers. Several types of rough vacuum pumps were evaluated, including scroll, roots, and diaphragm pumps. Tests included long term testing, speed curve generation, voltage variance, vibrations emissions and susceptibility, electromagnetic interference emissions and susceptibility, static leak rate, exhaust restriction, response/recovery time tests, and a contamination analysis for scroll pumps. Parameters were found for operation with helium, which often is not provided from the manufacturer

  19. Laws of Flow in Rough Pipes

    NASA Technical Reports Server (NTRS)

    Nikuradse, J

    1950-01-01

    An experimental investigation is made of the turbulent flow of water in pipes with various degrees of relative roughness. The pipes range in size from 25 to 100 millimeters in diameter and from 1800 to 7050 millimeters in length. Flow velocities permitted Reynolds numbers from about 10 (sup. 4) to 10 (sup. 6). The laws of resistance and velocity distributions were obtained as a function of relative roughness and Reynolds number. Mixing length, as described by Prandtl's mixing-length formula, is discussed in relation to the experimental results.

  20. Venus surface roughness and Magellan stereo data

    NASA Technical Reports Server (NTRS)

    Maurice, Kelly E.; Leberl, Franz W.; Norikane, L.; Hensley, Scott

    1994-01-01

    Presented are results of some studies to develop tools useful for the analysis of Venus surface shape and its roughness. Actual work was focused on Maxwell Montes. The analyses employ data acquired by means of NASA's Magellan satellite. The work is primarily concerned with deriving measurements of the Venusian surface using Magellan stereo SAR. Roughness was considered by means of a theoretical analyses based on digital elevation models (DEM's), on single Magellan radar images combined with radiometer data, and on the use of multiple overlapping Magellan radar images from cycles 1, 2, and 3, again combined with collateral radiometer data.