WorldWideScience

Sample records for generate surface features

  1. Multiscale vascular surface model generation from medical imaging data using hierarchical features.

    Science.gov (United States)

    Bekkers, Eric J; Taylor, Charles A

    2008-03-01

    Computational fluid dynamics (CFD) modeling of blood flow from image-based patient specific models can provide useful physiologic information for guiding clinical decision making. A novel method for the generation of image-based, 3-D, multiscale vascular surface models for CFD is presented. The method generates multiscale surfaces based on either a linear triangulated or a globally smooth nonuniform rational B-spline (NURB) representation. A robust local curvature analysis is combined with a novel global feature analysis to set mesh element size. The method is particularly useful for CFD modeling of complex vascular geometries that have a wide range of vasculature size scales, in conditions where 1) initial surface mesh density is an important consideration for balancing surface accuracy with manageable size volumetric meshes, 2) adaptive mesh refinement based on flow features makes an underlying explicit smooth surface representation desirable, and 3) semi-automated detection and trimming of a large number of inlet and outlet vessels expedites model construction.

  2. Generating Sub-Micron Features On Rough Surfaces Using Optical Trap Assisted Nanopatterning

    Science.gov (United States)

    Tsai, Yu-Cheng; Fardel, Romain; Arnold, Craig B.

    2010-10-01

    Near-field intensity enhancement enables laser modification of materials with feature sizes below the classical diffraction limit. However, the need to maintain close distances between the objective element and the substrate typically limit demonstrations of this technology to flat surfaces, even though there are many cases where the ability to produce sub-micron features on rough or structured surfaces are needed. Here, we show the use of a new technique, optical trap assisted nanopatterning (OTAN), for the production of nanoscale features on rippled substrates. The ability to position a microbead near-field objective close to the surface without the need for active feedback and control allows one to continuously move the bead across a rough surface without sticking. Sub-micron patterning of polyimide is demonstrated on surfaces with 1.1 μm steps showing good uniformity. Finally, the enabling technology allows for straightforward parallelization where multiple patterns can be created simultaneously over surface.

  3. Patch layout generation by detecting feature networks

    KAUST Repository

    Cao, Yuanhao

    2015-02-01

    The patch layout of 3D surfaces reveals the high-level geometric and topological structures. In this paper, we study the patch layout computation by detecting and enclosing feature loops on surfaces. We present a hybrid framework which combines several key ingredients, including feature detection, feature filtering, feature curve extension, patch subdivision and boundary smoothing. Our framework is able to compute patch layouts through concave features as previous approaches, but also able to generate nice layouts through smoothing regions. We demonstrate the effectiveness of our framework by comparing with the state-of-the-art methods.

  4. Reconstructing NURBS Surface with Features

    Institute of Scientific and Technical Information of China (English)

    SUN Chunhua

    2006-01-01

    The method of reconstructing NURBS surface with features is proposed in this paper. Features including boundary curves and feature points are recognized from the scanned data. An initial surface is constructed with boundary curves. The desired NURBS is determined by modifying the initial surface to pass through feature points. Lagrange multiplier is used to find the solution. The error analysis is then done. Examples are given to verify the algorithm at last. The method can keep some features fixed and be widely used in CAD modeling.

  5. System and method for investigating sub-surface features of a rock formation with acoustic sources generating coded signals

    Energy Technology Data Exchange (ETDEWEB)

    Vu, Cung Khac; Nihei, Kurt; Johnson, Paul A; Guyer, Robert; Ten Cate, James A; Le Bas, Pierre-Yves; Larmat, Carene S

    2014-12-30

    A system and a method for investigating rock formations includes generating, by a first acoustic source, a first acoustic signal comprising a first plurality of pulses, each pulse including a first modulated signal at a central frequency; and generating, by a second acoustic source, a second acoustic signal comprising a second plurality of pulses. A receiver arranged within the borehole receives a detected signal including a signal being generated by a non-linear mixing process from the first-and-second acoustic signal in a non-linear mixing zone within the intersection volume. The method also includes-processing the received signal to extract the signal generated by the non-linear mixing process over noise or over signals generated by a linear interaction process, or both.

  6. System and method for investigating sub-surface features of a rock formation with acoustic sources generating coded signals

    Science.gov (United States)

    Vu, Cung Khac; Nihei, Kurt; Johnson, Paul A; Guyer, Robert; Ten Cate, James A; Le Bas, Pierre-Yves; Larmat, Carene S

    2014-12-30

    A system and a method for investigating rock formations includes generating, by a first acoustic source, a first acoustic signal comprising a first plurality of pulses, each pulse including a first modulated signal at a central frequency; and generating, by a second acoustic source, a second acoustic signal comprising a second plurality of pulses. A receiver arranged within the borehole receives a detected signal including a signal being generated by a non-linear mixing process from the first-and-second acoustic signal in a non-linear mixing zone within the intersection volume. The method also includes-processing the received signal to extract the signal generated by the non-linear mixing process over noise or over signals generated by a linear interaction process, or both.

  7. System and method for investigating sub-surface features of a rock formation with acoustic sources generating conical broadcast signals

    Energy Technology Data Exchange (ETDEWEB)

    Vu, Cung Khac; Skelt, Christopher; Nihei, Kurt; Johnson, Paul A.; Guyer, Robert; Ten Cate, James A.; Le Bas, Pierre -Yves; Larmat, Carene S.

    2015-08-18

    A method of interrogating a formation includes generating a conical acoustic signal, at a first frequency--a second conical acoustic signal at a second frequency each in the between approximately 500 Hz and 500 kHz such that the signals intersect in a desired intersection volume outside the borehole. The method further includes receiving, a difference signal returning to the borehole resulting from a non-linear mixing of the signals in a mixing zone within the intersection volume.

  8. System and method for investigating sub-surface features of a rock formation with acoustic sources generating conical broadcast signals

    Science.gov (United States)

    Vu, Cung Khac; Skelt, Christopher; Nihei, Kurt; Johnson, Paul A.; Guyer, Robert; Ten Cate, James A.; Le Bas, Pierre -Yves; Larmat, Carene S.

    2015-08-18

    A method of interrogating a formation includes generating a conical acoustic signal, at a first frequency--a second conical acoustic signal at a second frequency each in the between approximately 500 Hz and 500 kHz such that the signals intersect in a desired intersection volume outside the borehole. The method further includes receiving, a difference signal returning to the borehole resulting from a non-linear mixing of the signals in a mixing zone within the intersection volume.

  9. Surface Features of Nanocrystalline Alloys

    Directory of Open Access Journals (Sweden)

    Marcel Miglierini

    2015-12-01

    Full Text Available Nanocrystalline alloys are prepared by controlled annealing of metallic glass precursors. The latter are obtained by rapid quenching of a melt on a rotating wheel. This process leads to structural deviation of the produced ribbons’ surfaces. Structural features of as-quenched and thermally annealed 57Fe81Mo8Cu1B10 ribbons were studied employing Conversion Electron Mössbauer Spectrometry (CEMS and Conversion X-ray Mössbauer Spectrometry (CXMS. Enrichment of the alloy’s composition in 57Fe helped in identification of surface crystallites that were formed even during the production process. Magnetite and bcc-Fe were found at the wheel side of the as-quenched ribbons whereas only bcc-Fe nanocrystals were uncovered at the opposite air side. Accelerated formation of bcc-Fe was observed in this side of the ribbons after annealing. The relative content of magnetite at the wheel side was almost stable in near surface areas (CEMS and in more deep subsurface regions (CXMS. It vanished completely after annealing at 550 °C. No magnetite was observed at the air side of the ribbons regardless the annealing temperature and/or depth of the scanned regions.

  10. Automatic Melody Generation System with Extraction Feature

    Science.gov (United States)

    Ida, Kenichi; Kozuki, Shinichi

    In this paper, we propose the melody generation system with the analysis result of an existing melody. In addition, we introduce the device that takes user's favor in the system. The melody generation is done by pitch's being arranged best on the given rhythm. The best standard is decided by using the feature element extracted from existing music by proposed method. Moreover, user's favor is reflected in the best standard by operating some of the feature element in users. And, GA optimizes the pitch array based on the standard, and achieves the system.

  11. Structural aspects and porosity features of nano-size high surface area alumina-silica mixed oxide catalyst generated through hybrid sol-gel route

    Energy Technology Data Exchange (ETDEWEB)

    Padmaja, P. [Ceramic Technology Division, Regional Research Laboratory (CSIR), Trivandrum 695019, Kerala (India)]. E-mail: padmavasudev@yahoo.com; Warrier, K.G.K. [Ceramic Technology Division, Regional Research Laboratory (CSIR), Trivandrum 695019, Kerala (India)]. E-mail: kgk_warrier@yahoo.com; Padmanabhan, M. [School of Chemical Sciences, Mahatma Gandhi University, Kottayam 686560, Kerala (India); Wunderlich, W. [Graduate School of Engineering, Nagoya Institute of Technology, 466-8555 Nagoya (Japan); Berry, F.J. [Department of Chemistry, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Mortimer, M. [Department of Chemistry, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Creamer, N.J. [Department of Chemistry, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)

    2006-01-10

    Alumina-silica mixed oxide nano-catalyst materials with compositions 83.6 wt.% Al{sub 2}O{sub 3}-16.4 wt.% SiO{sub 2} (3Al{sub 2}O{sub 3}.1SiO{sub 2}), 71.82 wt.% Al{sub 2}O{sub 3}-28.18 wt.% SiO{sub 2} (3Al{sub 2}O{sub 3}.2SiO{sub 2}), 62.84 wt.% Al{sub 2}O{sub 3}-37.16 wt.% SiO{sub 2} (3Al{sub 2}O{sub 3}.3SiO{sub 2}) and 56.03 wt.% Al{sub 2}O{sub 3}-43.97 wt.% SiO{sub 2} (3Al{sub 2}O{sub 3}.4SiO{sub 2}) have been prepared by a hybrid sol-gel technique using boehmite as the precursor for alumina and tetraethoxysilane as that for silica. The bonding characteristics and coordination features around Al and Si in the mixed oxide catalysts have been studied using FTIR and {sup 27}Al MAS NMR after calcination at 400 deg. C which is the temperature region where cross-condensation is seen to take place. A high BET specific surface area of 287 m{sup 2} g{sup -1} is obtained for 3Al{sub 2}O{sub 3}.1SiO{sub 2} mixed oxide composition. The porosity features are further established by BET adsorption isotherms and pore size distribution analysis. The temperature-programmed desorption studies showed more surface active sites for the silica-rich composition, suggesting enhanced catalytic potential. The TEM features of the mixed oxides showed a homogeneous distribution of alumina and silica phases with particle sizes in the nano-range. The low silica-containing mixed oxide showed a needle-like morphology with a high aspect ratio of 1:50 and {approx}10 nm particle size while the silica-rich composition had particle size in a wide range ({approx}20-75 nm)

  12. Surface characterization based upon significant topographic features

    Energy Technology Data Exchange (ETDEWEB)

    Blanc, J; Grime, D; Blateyron, F, E-mail: fblateyron@digitalsurf.fr [Digital Surf, 16 rue Lavoisier, F-25000 Besancon (France)

    2011-08-19

    Watershed segmentation and Wolf pruning, as defined in ISO 25178-2, allow the detection of significant features on surfaces and their characterization in terms of dimension, area, volume, curvature, shape or morphology. These new tools provide a robust way to specify functional surfaces.

  13. Feature Extraction by Wavelet Decomposition of Surface

    Directory of Open Access Journals (Sweden)

    Prashant Singh

    2010-07-01

    Full Text Available The paper presents a new approach to surface acoustic wave (SAW chemical sensor array design and data processing for recognition of volatile organic compounds (VOCs based on transient responses. The array is constructed of variable thickness single polymer-coated SAW oscillator sensors. The thickness of polymer coatings are selected such that during the sensing period, different sensors are loaded with varied levels of diffusive inflow of vapour species due to different stages of termination of equilibration process. Using a single polymer for coating the individual sensors with different thickness introduces vapour-specific kinetics variability in transient responses. The transient shapes are analysed by wavelet decomposition based on Daubechies mother wavelets. The set of discrete wavelet transform (DWT approximation coefficients across the array transients is taken to represent the vapour sample in two alternate ways. In one, the sets generated by all the transients are combined into a single set to give a single representation to the vapour. In the other, the set of approximation coefficients at each data point generated by all transients is taken to represent the vapour. The latter results in as many alternate representations as there are approximation coefficients. The alternate representations of a vapour sample are treated as different instances or realisations for further processing. The wavelet analysis is then followed by the principal component analysis (PCA to create new feature space. A comparative analysis of the feature spaces created by both the methods leads to the conclusion that both methods yield complimentary information: the one reveals intrinsic data variables, and the other enhances class separability. The present approach is validated by generating synthetic transient response data based on a prototype polyisobutylene (PIB coated 3-element SAW sensor array exposed to 7 VOC vapours: chloroform, chlorobenzene o

  14. Exploiting surface features for the prediction of podcast preference

    NARCIS (Netherlands)

    Tsagkias, M.; Larson, M.; de Rijke, M.

    2009-01-01

    Podcasts display an unevenness characteristic of domains dominated by user generated content, resulting in potentially radical variation of the user preference they enjoy. We report on work that uses easily extractable surface features of podcasts in order to achieve solid performance on two podcast

  15. Generating Best Features for Web Page Classification

    Directory of Open Access Journals (Sweden)

    K. Selvakuberan

    2008-03-01

    Full Text Available As the Internet provides millions of web pages for each and every search term, getting interesting and required results quickly from the Web becomes very difficult. Automatic classification of web pages into relevant categories is the current research topic which helps the search engine to get relevant results. As the web pages contain many irrelevant, infrequent and stop words that reduce the performance of the classifier, extracting or selecting representative features from the web page is an essential pre-processing step. The goal of this paper is to find minimum number of highly qualitative features by integrating feature selection techniques. We conducted experiments with various numbers of features selected by different feature selection algorithms on a well defined initial set of features and show that cfssubset evaluator combined with term frequency method gives minimal qualitative features enough to attain considerable classification accuracy.

  16. Method of generating features optimal to a dataset and classifier

    Energy Technology Data Exchange (ETDEWEB)

    Bruillard, Paul J.; Gosink, Luke J.; Jarman, Kenneth D.

    2016-10-18

    A method of generating features optimal to a particular dataset and classifier is disclosed. A dataset of messages is inputted and a classifier is selected. An algebra of features is encoded. Computable features that are capable of describing the dataset from the algebra of features are selected. Irredundant features that are optimal for the classifier and the dataset are selected.

  17. Efficient Generation and Selection of Combined Features for Improved Classification

    KAUST Repository

    Shono, Ahmad N.

    2014-05-01

    This study contributes a methodology and associated toolkit developed to allow users to experiment with the use of combined features in classification problems. Methods are provided for efficiently generating combined features from an original feature set, for efficiently selecting the most discriminating of these generated combined features, and for efficiently performing a preliminary comparison of the classification results when using the original features exclusively against the results when using the selected combined features. The potential benefit of considering combined features in classification problems is demonstrated by applying the developed methodology and toolkit to three sample data sets where the discovery of combined features containing new discriminating information led to improved classification results.

  18. METHOD TO EXTRACT BLEND SURFACE FEATURE IN REVERSE ENGINEERING

    Institute of Scientific and Technical Information of China (English)

    Lü Zhen; Ke Yinglin; Sun Qing; Kelvin W; Huang Xiaoping

    2003-01-01

    A new method of extraction of blend surface feature is presented. It contains two steps: segmentation and recovery of parametric representation of the blend. The segmentation separates the points in the blend region from the rest of the input point cloud with the processes of sampling point data, estimation of local surface curvature properties and comparison of maximum curvature values. The recovery of parametric representation generates a set of profile curves by marching throughout the blend and fitting cylinders. Compared with the existing approaches of blend surface feature extraction, the proposed method reduces the requirement of user interaction and is capable of extracting blend surface with either constant radius or variable radius. Application examples are presented to verify the proposed method.

  19. Grammar-based feature generation for time-series prediction

    CERN Document Server

    De Silva, Anthony Mihirana

    2015-01-01

    This book proposes a novel approach for time-series prediction using machine learning techniques with automatic feature generation. Application of machine learning techniques to predict time-series continues to attract considerable attention due to the difficulty of the prediction problems compounded by the non-linear and non-stationary nature of the real world time-series. The performance of machine learning techniques, among other things, depends on suitable engineering of features. This book proposes a systematic way for generating suitable features using context-free grammar. A number of feature selection criteria are investigated and a hybrid feature generation and selection algorithm using grammatical evolution is proposed. The book contains graphical illustrations to explain the feature generation process. The proposed approaches are demonstrated by predicting the closing price of major stock market indices, peak electricity load and net hourly foreign exchange client trade volume. The proposed method ...

  20. Metacatalog of Planetary Surface Features for Multicriteria Evaluation of Surface Evolution: the Integrated Planetary Feature Database

    Science.gov (United States)

    Hargitai, Henrik

    2016-10-01

    We have created a metacatalog, or catalog or catalogs, of surface features of Mars that also includes the actual data in the catalogs listed. The goal is to make mesoscale surface feature databases available in one place, in a GIS-ready format. The databases can be directly imported to ArcGIS or other GIS platforms, like Google Mars. Some of the catalogs in our database are also ingested into the JMARS platform.All catalogs have been previously published in a peer-reviewed journal, but they may contain updates of the published catalogs. Many of the catalogs are "integrated", i.e. they merge databases or information from various papers on the same topic, including references to each individual features listed.Where available, we have included shapefiles with polygon or linear features, however, most of the catalogs only contain point data of their center points and morphological data.One of the unexpected results of the planetary feature metacatalog is that some features have been described by several papers, using different, i.e., conflicting designations. This shows the need for the development of an identification system suitable for mesoscale (100s m to km sized) features that tracks papers and thus prevents multiple naming of the same feature.The feature database can be used for multicriteria analysis of a terrain, thus enables easy distribution pattern analysis and the correlation of the distribution of different landforms and features on Mars. Such catalog makes a scientific evaluation of potential landing sites easier and more effective during the selection process and also supports automated landing site selections.The catalog is accessible at https://planetarydatabase.wordpress.com/.

  1. Robust Features Of Surface Electromyography Signal

    Science.gov (United States)

    Sabri, M. I.; Miskon, M. F.; Yaacob, M. R.

    2013-12-01

    Nowadays, application of robotics in human life has been explored widely. Robotics exoskeleton system are one of drastically areas in recent robotic research that shows mimic impact in human life. These system have been developed significantly to be used for human power augmentation, robotics rehabilitation, human power assist, and haptic interaction in virtual reality. This paper focus on solving challenges in problem using neural signals and extracting human intent. Commonly, surface electromyography signal (sEMG) are used in order to control human intent for application exoskeleton robot. But the problem lies on difficulty of pattern recognition of the sEMG features due to high noises which are electrode and cable motion artifact, electrode noise, dermic noise, alternating current power line interface, and other noise came from electronic instrument. The main objective in this paper is to study the best features of electromyography in term of time domain (statistical analysis) and frequency domain (Fast Fourier Transform).The secondary objectives is to map the relationship between torque and best features of muscle unit activation potential (MaxPS and RMS) of biceps brachii. This project scope use primary data of 2 male sample subject which using same dominant hand (right handed), age between 20-27 years old, muscle diameter 32cm to 35cm and using single channel muscle (biceps brachii muscle). The experiment conduct 2 times repeated task of contraction and relaxation of biceps brachii when lifting different load from no load to 3kg with ascending 1kg The result shows that Fast Fourier Transform maximum power spectrum (MaxPS) has less error than mean value of reading compare to root mean square (RMS) value. Thus, Fast Fourier Transform maximum power spectrum (MaxPS) show the linear relationship against torque experience by elbow joint to lift different load. As the conclusion, the best features is MaxPS because it has the lowest error than other features and show

  2. Analytical Features: A Knowledge-Based Approach to Audio Feature Generation

    Directory of Open Access Journals (Sweden)

    Pachet François

    2009-01-01

    Full Text Available We present a feature generation system designed to create audio features for supervised classification tasks. The main contribution to feature generation studies is the notion of analytical features (AFs, a construct designed to support the representation of knowledge about audio signal processing. We describe the most important aspects of AFs, in particular their dimensional type system, on which are based pattern-based random generators, heuristics, and rewriting rules. We show how AFs generalize or improve previous approaches used in feature generation. We report on several projects using AFs for difficult audio classification tasks, demonstrating their advantage over standard audio features. More generally, we propose analytical features as a paradigm to bring raw signals into the world of symbolic computation.

  3. D Surface Generation from Aerial Thermal Imagery

    Science.gov (United States)

    Khodaei, B.; Samadzadegan, F.; Dadras Javan, F.; Hasani, H.

    2015-12-01

    Aerial thermal imagery has been recently applied to quantitative analysis of several scenes. For the mapping purpose based on aerial thermal imagery, high accuracy photogrammetric process is necessary. However, due to low geometric resolution and low contrast of thermal imaging sensors, there are some challenges in precise 3D measurement of objects. In this paper the potential of thermal video in 3D surface generation is evaluated. In the pre-processing step, thermal camera is geometrically calibrated using a calibration grid based on emissivity differences between the background and the targets. Then, Digital Surface Model (DSM) generation from thermal video imagery is performed in four steps. Initially, frames are extracted from video, then tie points are generated by Scale-Invariant Feature Transform (SIFT) algorithm. Bundle adjustment is then applied and the camera position and orientation parameters are determined. Finally, multi-resolution dense image matching algorithm is used to create 3D point cloud of the scene. Potential of the proposed method is evaluated based on thermal imaging cover an industrial area. The thermal camera has 640×480 Uncooled Focal Plane Array (UFPA) sensor, equipped with a 25 mm lens which mounted in the Unmanned Aerial Vehicle (UAV). The obtained results show the comparable accuracy of 3D model generated based on thermal images with respect to DSM generated from visible images, however thermal based DSM is somehow smoother with lower level of texture. Comparing the generated DSM with the 9 measured GCPs in the area shows the Root Mean Square Error (RMSE) value is smaller than 5 decimetres in both X and Y directions and 1.6 meters for the Z direction.

  4. Dialogical surface text features in abstracts

    Directory of Open Access Journals (Sweden)

    Ingrid García-Østbye

    2008-04-01

    Full Text Available A sample driven description of Research Article-Comment-Reply (RA-C-R abstracts in terms of abstract sentence length, reference, possessive structures, modal verbs and word range was carried out to find out whether their surface text features showed some trace of a dialogical construction of knowledge within the psychology discourse community. The study served an exploratory purpose. A Boolean search was conducted in the PsycLIT database yielding a sample of 149 PsycLIT RA-C-R abstracts (13,978 words. Relative frequency percent distributions were calculated for all variables, including reported speech verbs. Specific comparisons with a Medline corpus were conducted and variations were accounted for in terms of scientific discourse characteristics, field, database policies, and dialogical nature; that is, in the framework provided by the strands of research of quantitative applied linguistics, social concerns in genre analysis and the model monopoly theory developed in the implementation in sociology of the systems theory. The results suggest: (i a word range affected by both psychology as a discipline and the dialogical content on which PsycLIT RA-C-R abstracts report; (ii a complementarity of reference and possessive structures characterised by features of scientific discourse, feedback genres and dialogical dimensions; (iii the presence of both deontic and epistemic modality in the modal verbs of our sample; (iv and also that abstract length, sentence length and number of sentences per paragraph in our sample may not vary greatly in general terms from those of the social sciences.

  5. Ultrasonic Nanocoining of Sub-micrometer Surface Features

    Science.gov (United States)

    Nowak, William John, Jr.

    The goal of this work is to develop a machining process to rapidly generate large areas of sub-micrometer surface features in industrially-feasible amounts of time. These surface features, inspired by designs found in nature, can be sized to produce desired behavior including anti-reflective (AR), superhydrophobic, or syperhydrophilic properties. Current methods of producing these features produce high-fidelity replications, but often require several steps to complete and are not economically feasible in a mass-production setting. This process uses a diamond die containing thousands of subwavelength features mounted to a high speed actuator on the axis of a diamond turning machine. The die is pressed into the workpiece with an elliptical path that matches the surface speed of the moving workpiece and minimizes distortion caused by mismatches in velocity. These die indents are tiled together to create large areas of uniform features, which can then be easily transferred to pliable coatings. Because the die is small (20x20 im), the indentations must occur rapidly (40 kHz) to make nanocoining an industrially feasible process. To produce the ultrasonic 2-D motion for indenting, an actuator was designed that resonates in two orthogonal directions at the same frequency. Analytical solutions were first used to determine the approximate geometry to achieve the desired resonant behavior. Finite element analysis (FEA) is then employed to fine-tune the geometry of the device to meet amplitude requirements. Prototypes were constructed and measured to demonstrate the utility of the proposed design method. A controller is designed and implemented to automatically track the resonant frequency and maintain the desired actuator behavior to ensure the indents are formed uniformly over large areas despite piezoelectric self-heating effects and other environmental affects that impact device resonance. Other control strategies that are required for maintaining uniform spacing of

  6. Geometric features for voxel-based surface recognition

    OpenAIRE

    Yarotsky, Dmitry

    2017-01-01

    We introduce a library of geometric voxel features for CAD surface recognition/retrieval tasks. Our features include local versions of the intrinsic volumes (the usual 3D volume, surface area, integrated mean and Gaussian curvature) and a few closely related quantities. We also compute Haar wavelet and statistical distribution features by aggregating raw voxel features. We apply our features to object classification on the ESB data set and demonstrate accurate results with a small number of s...

  7. FEATURES OF CALCULATION OF THE NONCONTACT ELECTRIC POWER GENERATORS

    Directory of Open Access Journals (Sweden)

    Kvitko A. V.

    2015-10-01

    Full Text Available The article shows that to improve the performance of autonomous systems we need new methods and principles of their design, associated with both the use of renewable sources and the application of new technical solutions of electromechanical generators and static stabilizers and inverters electric power settings. We have disclosed modern requirements for generators of electric power, as well as features of calculating the parameters of contactless electrical power generators: asynchronous generators capacitive excitation and asynchronous generators with permanent magnets. The article presents some analytical expressions for calculating the electrical losses and the efficiency of the generators, specific weight and power. It is shown, that expedient to designing contactless electrical power generators to carry out as part of the autonomous electricity supply systems, as it is sometimes advantageous to understate the main criteria of efficiency of generators, in order to improve, for example, weight and overall dimensions of static converters. The conclusion is made that in order to improve the efficiency of designing contactless electrical power generators in the early stages of designing it is necessary to carry out a preliminary assessment of the main criteria of efficiency of contactless electrical machines. We have also discussed analytical expressions, which might be used for preliminary evaluation of application features for various types of contactless generators in the stand-alone electricity supply systems taking into account the conditions of use

  8. Surface osteosarcoma: Clinical features and therapeutic implications

    Directory of Open Access Journals (Sweden)

    H. Nouri

    2015-12-01

    Conclusion: Histological grade of malignancy is the main point to assess in surface osteosarcoma since it determines treatment and prognosis. Low grade lesions should be treated by wide resection, while high grade lesions need more aggressive surgical approach associated to post operative chemotherapy.

  9. Feature Selection for Generator Excitation Neurocontroller Development Using Filter Technique

    Directory of Open Access Journals (Sweden)

    Abdul Ghani Abro

    2011-09-01

    Full Text Available Essentially, motive behind using control system is to generate suitable control signal for yielding desired response of a physical process. Control of synchronous generator has always remained very critical in power system operation and control. For certain well known reasons power generators are normally operated well below their steady state stability limit. This raises demand for efficient and fast controllers. Artificial intelligence has been reported to give revolutionary outcomes in the field of control engineering. Artificial Neural Network (ANN, a branch of artificial intelligence has been used for nonlinear and adaptive control, utilizing its inherent observability. The overall performance of neurocontroller is dependent upon input features too. Selecting optimum features to train a neurocontroller optimally is very critical. Both quality and size of data are of equal importance for better performance. In this work filter technique is employed to select independent factors for ANN training.

  10. The Vegetation Red Edge Spectroscopic Feature as a Surface Biomarker

    CERN Document Server

    Seager, S

    2002-01-01

    The search for Earth-like extrasolar planets is in part motivated by the potential detection of spectroscopic biomarkers. Spectroscopic biomarkers are spectral features that are either consistent with life, indicative of habitability, or provide clues to a planet's habitability. Most attention so far has been given to atmospheric biomarkers, gases such as O2, O3, H2O, CO, and CH4. Here we discuss surface biomarkers. Surface biomarkers that have large, distinct, abrupt changes in their spectra may be detectable in an extrasolar planet's spectrum at wavelengths that penetrate to the planetary surface. Earth has such a surface biomarker: the vegetation "red edge" spectroscopic feature. Recent interest in Earth's surface biomarker has motivated Earthshine observations of the spatially unresolved Earth and two recent studies may have detected the vegetation red edge feature in Earth's hemispherically integrated spectrum. A photometric time series in different colors should help in detecting unusual surface feature...

  11. Generating Feature Spaces for Linear Algorithms with Regularized Sparse Kernel Slow Feature Analysis

    NARCIS (Netherlands)

    Böhmer, W.; Grünewälder, S.; Nickisch, H.; Obermayer, K.

    2013-01-01

    Without non-linear basis functions many problems can not be solved by linear algorithms. This article proposes a method to automatically construct such basis functions with slow feature analysis (SFA). Non-linear optimization of this unsupervised learning method generates an orthogonal basis on the

  12. Robust Feature Detection and Local Classification for Surfaces Based on Moment Analysis

    OpenAIRE

    2004-01-01

    The stable local classification of discrete surfaces with respect to features such as edges and corners or concave and convex regions, respectively, is as quite difficult as well as indispensable for many surface processing applications. Usually, the feature detection is done via a local curvature analysis. If concerned with large triangular and irregular grids, e.g., generated via a marching cube algorithm, the detectors are tedious to treat and a robust classification is hard to achieve. He...

  13. Manufacturing of Superhydrophobic Surfaces with Nanoscale and Microscale Features

    Energy Technology Data Exchange (ETDEWEB)

    None

    2009-06-01

    This factsheet describes a research project that will develop a technology that will enable nanoscale and microscale superhydrophobic (SHP) features to be imaged onto surfaces for the high-volume manufacturing of water-repellent components and coatings.

  14. Generating One Biometric Feature from Another: Faces from Fingerprints

    Directory of Open Access Journals (Sweden)

    Seref Sagiroglu

    2010-04-01

    Full Text Available This study presents a new approach based on artificial neural networks for generating one biometric feature (faces from another (only fingerprints. An automatic and intelligent system was designed and developed to analyze the relationships among fingerprints and faces and also to model and to improve the existence of the relationships. The new proposed system is the first study that generates all parts of the face including eyebrows, eyes, nose, mouth, ears and face border from only fingerprints. It is also unique and different from similar studies recently presented in the literature with some superior features. The parameter settings of the system were achieved with the help of Taguchi experimental design technique. The performance and accuracy of the system have been evaluated with 10-fold cross validation technique using qualitative evaluation metrics in addition to the expanded quantitative evaluation metrics. Consequently, the results were presented on the basis of the combination of these objective and subjective metrics for illustrating the qualitative properties of the proposed methods as well as a quantitative evaluation of their performances. Experimental results have shown that one biometric feature can be determined from another. These results have once more indicated that there is a strong relationship between fingerprints and faces.

  15. Generating one biometric feature from another: faces from fingerprints.

    Science.gov (United States)

    Ozkaya, Necla; Sagiroglu, Seref

    2010-01-01

    This study presents a new approach based on artificial neural networks for generating one biometric feature (faces) from another (only fingerprints). An automatic and intelligent system was designed and developed to analyze the relationships among fingerprints and faces and also to model and to improve the existence of the relationships. The new proposed system is the first study that generates all parts of the face including eyebrows, eyes, nose, mouth, ears and face border from only fingerprints. It is also unique and different from similar studies recently presented in the literature with some superior features. The parameter settings of the system were achieved with the help of Taguchi experimental design technique. The performance and accuracy of the system have been evaluated with 10-fold cross validation technique using qualitative evaluation metrics in addition to the expanded quantitative evaluation metrics. Consequently, the results were presented on the basis of the combination of these objective and subjective metrics for illustrating the qualitative properties of the proposed methods as well as a quantitative evaluation of their performances. Experimental results have shown that one biometric feature can be determined from another. These results have once more indicated that there is a strong relationship between fingerprints and faces.

  16. On compact generation of some deformed surfaces

    CERN Document Server

    Lowen, Wendy

    2012-01-01

    We obtain a theorem which allows to prove compact generation of derived categories of Grothendieck categories, based upon certain coverings by localizations. This theorem follows from an application of Rouquier's cocovering theorem in the triangulated context, and it implies Neeman's result on compact generation of quasi-compact separated schemes. We investigate applications of our theorem to non-commutative deformations of such schemes. In general there are obstructions, but for instance our approach yields compact generation of all first order deformations of quasi-projective surfaces.

  17. Determination of feature generation methods for PTZ camera object tracking

    Science.gov (United States)

    Doyle, Daniel D.; Black, Jonathan T.

    2012-06-01

    Object detection and tracking using computer vision (CV) techniques have been widely applied to sensor fusion applications. Many papers continue to be written that speed up performance and increase learning of artificially intelligent systems through improved algorithms, workload distribution, and information fusion. Military application of real-time tracking systems is becoming more and more complex with an ever increasing need of fusion and CV techniques to actively track and control dynamic systems. Examples include the use of metrology systems for tracking and measuring micro air vehicles (MAVs) and autonomous navigation systems for controlling MAVs. This paper seeks to contribute to the determination of select tracking algorithms that best track a moving object using a pan/tilt/zoom (PTZ) camera applicable to both of the examples presented. The select feature generation algorithms compared in this paper are the trained Scale-Invariant Feature Transform (SIFT) and Speeded Up Robust Features (SURF), the Mixture of Gaussians (MoG) background subtraction method, the Lucas- Kanade optical flow method (2000) and the Farneback optical flow method (2003). The matching algorithm used in this paper for the trained feature generation algorithms is the Fast Library for Approximate Nearest Neighbors (FLANN). The BSD licensed OpenCV library is used extensively to demonstrate the viability of each algorithm and its performance. Initial testing is performed on a sequence of images using a stationary camera. Further testing is performed on a sequence of images such that the PTZ camera is moving in order to capture the moving object. Comparisons are made based upon accuracy, speed and memory.

  18. An ontology design pattern for surface water features

    Science.gov (United States)

    Sinha, Gaurav; Mark, David; Kolas, Dave; Varanka, Dalia; Romero, Boleslo E.; Feng, Chen-Chieh; Usery, E. Lynn; Liebermann, Joshua; Sorokine, Alexandre

    2014-01-01

    Surface water is a primary concept of human experience but concepts are captured in cultures and languages in many different ways. Still, many commonalities exist due to the physical basis of many of the properties and categories. An abstract ontology of surface water features based only on those physical properties of landscape features has the best potential for serving as a foundational domain ontology for other more context-dependent ontologies. The Surface Water ontology design pattern was developed both for domain knowledge distillation and to serve as a conceptual building-block for more complex or specialized surface water ontologies. A fundamental distinction is made in this ontology between landscape features that act as containers (e.g., stream channels, basins) and the bodies of water (e.g., rivers, lakes) that occupy those containers. Concave (container) landforms semantics are specified in a Dry module and the semantics of contained bodies of water in a Wet module. The pattern is implemented in OWL, but Description Logic axioms and a detailed explanation is provided in this paper. The OWL ontology will be an important contribution to Semantic Web vocabulary for annotating surface water feature datasets. Also provided is a discussion of why there is a need to complement the pattern with other ontologies, especially the previously developed Surface Network pattern. Finally, the practical value of the pattern in semantic querying of surface water datasets is illustrated through an annotated geospatial dataset and sample queries using the classes of the Surface Water pattern.

  19. Retention of features on a mapped Drosophila brain surface using a Bézier-tube-based surface model averaging technique.

    Science.gov (United States)

    Chen, Guan-Yu; Wu, Cheng-Chi; Shao, Hao-Chiang; Chang, Hsiu-Ming; Chiang, Ann-Shyn; Chen, Yung-Chang

    2012-12-01

    Model averaging is a widely used technique in biomedical applications. Two established model averaging methods, iterative shape averaging (ISA) method and virtual insect brain (VIB) method, have been applied to several organisms to generate average representations of their brain surfaces. However, without sufficient samples, some features of the average Drosophila brain surface obtained using the above methods may disappear or become distorted. To overcome this problem, we propose a Bézier-tube-based surface model averaging strategy. The proposed method first compensates for disparities in position, orientation, and dimension of input surfaces, and then evaluates the average surface by performing shape-based interpolation. Structural features with larger individual disparities are simplified with half-ellipse-shaped Bézier tubes, and are unified according to these tubes to avoid distortion during the averaging process. Experimental results show that the average model yielded by our method could preserve fine features and avoid structural distortions even if only a limit amount of input samples are used. Finally, we qualitatively compare our results with those obtained by ISA and VIB methods by measuring the surface-to-surface distances between input surfaces and the averaged ones. The comparisons show that the proposed method could generate a more representative average surface than both ISA and VIB methods.

  20. METHOD FOR ADAPTIVE MESH GENERATION BASED ON GEOMETRICAL FEATURES OF 3D SOLID

    Institute of Scientific and Technical Information of China (English)

    HUANG Xiaodong; DU Qungui; YE Bangyan

    2006-01-01

    In order to provide a guidance to specify the element size dynamically during adaptive finite element mesh generation, adaptive criteria are firstly defined according to the relationships between the geometrical features and the elements of 3D solid. Various modes based on different datum geometrical elements, such as vertex, curve, surface, and so on, are then designed for generating local refmed mesh. With the guidance of the defined criteria, different modes are automatically selected to apply on the appropriate datum objects to program the element size in the local special areas. As a result, the control information of element size is successfully programmed coveting the entire domain based on the geometrical features of 3D solid. A new algorithm based on Delaunay triangulation is then developed for generating 3D adaptive fmite element mesh, in which the element size is dynamically specified to catch the geometrical features and suitable tetrahedron facets are selected to locate interior nodes continuously. As a result, adaptive mesh with good-quality elements is generated. Examples show that the proposed method can be successfully applied to adaptive finite element mesh automatic generation based on the geometrical features of 3D solid.

  1. Image Relaxation Matching Based on Feature Points for DSM Generation

    Institute of Scientific and Technical Information of China (English)

    ZHENG Shunyi; ZHANG Zuxun; ZHANG Jianqing

    2004-01-01

    In photogrammetry and remote sensing, image matching is a basic and crucial process for automatic DEM generation. In this paper we presented a image relaxation matching method based on feature points. This method can be considered as an extention of regular grid point based matching. It avoids the shortcome of grid point based matching. For example, with this method, we can avoid low or even no texture area where errors frequently appear in cross correlaton matching. In the mean while, it makes full use of some mature techniques such as probability relaxation, image pyramid and the like which have already been successfully used in grid point matching process. Application of the technique to DEM generaton in different regions proved that it is more reasonable and reliable.

  2. An Ontology Design Pattern for Surface Water Features

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Gaurav [Ohio University; Mark, David [University at Buffalo (SUNY); Kolas, Dave [Raytheon BBN Technologies; Varanka, Dalia [U.S. Geological Survey, Rolla, MO; Romero, Boleslo E [University of California, Santa Barbara; Feng, Chen-Chieh [National University of Singapore; Usery, Lynn [U.S. Geological Survey, Rolla, MO; Liebermann, Joshua [Tumbling Walls, LLC; Sorokine, Alexandre [ORNL

    2014-01-01

    Surface water is a primary concept of human experience but concepts are captured in cultures and languages in many different ways. Still, many commonalities can be found due to the physical basis of many of the properties and categories. An abstract ontology of surface water features based only on those physical properties of landscape features has the best potential for serving as a foundational domain ontology. It can then be used to systematically incor-porate concepts that are specific to a culture, language, or scientific domain. The Surface Water ontology design pattern was developed both for domain knowledge distillation and to serve as a conceptual building-block for more complex surface water ontologies. A fundamental distinction is made in this on-tology between landscape features that act as containers (e.g., stream channels, basins) and the bodies of water (e.g., rivers, lakes) that occupy those containers. Concave (container) landforms semantics are specified in a Dry module and the semantics of contained bodies of water in a Wet module. The pattern is imple-mented in OWL, but Description Logic axioms and a detailed explanation is provided. The OWL ontology will be an important contribution to Semantic Web vocabulary for annotating surface water feature datasets. A discussion about why there is a need to complement the pattern with other ontologies, es-pecially the previously developed Surface Network pattern is also provided. Fi-nally, the practical value of the pattern in semantic querying of surface water datasets is illustrated through a few queries and annotated geospatial datasets.

  3. Development of Generative Learning Objects Using Feature Diagrams and Generative Techniques

    OpenAIRE

    Vytautas STUIKYS; Robertas DAMASEVICIUS

    2008-01-01

    Learning Objects (LOs) play a key role for supporting eLearning. In general, however, the development of LOs remains a vague issue, because there is still no clearly defined and widely adopted LO specification and development methodology. We combined two technological paradigms (feature diagrams (FDs) and generative techniques) into a coherent methodology to enhance reusability and productivity in the development of LOs. FDs are used for knowledge representation, modelling variability of the ...

  4. Model-based defect detection on structured surfaces having optically unresolved features.

    Science.gov (United States)

    O'Connor, Daniel; Henning, Andrew J; Sherlock, Ben; Leach, Richard K; Coupland, Jeremy; Giusca, Claudiu L

    2015-10-20

    In this paper, we demonstrate, both numerically and experimentally, a method for the detection of defects on structured surfaces having optically unresolved features. The method makes use of synthetic reference data generated by an observational model that is able to simulate the response of the selected optical inspection system to the ideal structure, thereby providing an ideal measure of deviation from nominal geometry. The method addresses the high dynamic range challenge faced in highly parallel manufacturing by enabling the use of low resolution, wide field of view optical systems for defect detection on surfaces containing small features over large regions.

  5. Hexahedral mesh generation via the dual arrangement of surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, S.A.; Tautges, T.J. [Sandia National Labs., Albuquerque, NM (United States)

    1997-12-31

    Given a general three-dimensional geometry with a prescribed quadrilateral surface mesh, the authors consider the problem of constructing a hexahedral mesh of the geometry whose boundary is exactly the prescribed surface mesh. Due to the specialized topology of hexahedra, this problem is more difficult than the analogous one for tetrahedra. Folklore has maintained that a surface mesh must have a constrained structure in order for there to exist a compatible hexahedral mesh. However, they have proof that a surface mesh need only satisfy mild parity conditions, depending on the topology of the three-dimensional geometry, for there to exist a compatible hexahedral mesh. The proof is based on the realization that a hexahedral mesh is dual to an arrangement of surfaces, and the quadrilateral surface mesh is dual to the arrangement of curves bounding these surfaces. The proof is constructive and they are currently developing an algorithm called Whisker Weaving (WW) that mirrors the proof steps. Given the bounding curves, WW builds the topological structure of an arrangement of surfaces having those curves as its boundary. WW progresses in an advancing front manner. Certain local rules are applied to avoid structures that lead to poor mesh quality. Also, after the arrangement is constructed, additional surfaces are inserted to separate features, so e.g., no two hexahedra share more than one quadrilateral face. The algorithm has generated meshes for certain non-trivial problems, but is currently unreliable. The authors are exploring strategies for consistently selecting which portion of the surface arrangement to advance based on the existence proof. This should lead us to a robust algorithm for arbitrary geometries and surface meshes.

  6. Nanometer polymer surface features: the influence on surface energy, protein adsorption and endothelial cell adhesion

    Science.gov (United States)

    Carpenter, Joseph; Khang, Dongwoo; Webster, Thomas J.

    2008-12-01

    Current small diameter (require an eight-week in vitro culture period prior to implantation—too long for immediate clinical bedside applications. Previous in vitro studies have shown that nanostructured poly(lactic-co-glycolic acid) (PLGA) surfaces elevated endothelial cell adhesion, proliferation, and extracellular matrix synthesis when compared to nanosmooth surfaces. Nonetheless, these studies failed to address the importance of lateral and vertical surface feature dimensionality coupled with surface free energy; nor did such studies elicit an optimum specific surface feature size for promoting endothelial cell adhesion. In this study, a series of highly ordered nanometer to submicron structured PLGA surfaces of identical chemistry were created using a technique employing polystyrene nanobeads and poly(dimethylsiloxane) (PDMS) molds. Results demonstrated increased endothelial cell adhesion on PLGA surfaces with vertical surface features of size less than 18.87 nm but greater than 0 nm due to increased surface energy and subsequently protein (fibronectin and collagen type IV) adsorption. Furthermore, this study provided evidence that the vertical dimension of nanometer surface features, rather than the lateral dimension, is largely responsible for these increases. In this manner, this study provides key design parameters that may promote vascular graft efficacy.

  7. Surface Electromyography Feature Extraction Based on Wavelet Transform

    Directory of Open Access Journals (Sweden)

    Farzaneh Akhavan Mahdavi

    2012-12-01

    Full Text Available Considering the vast variety of EMG signal applications such as rehabilitation of people suffering from some mobility limitations, scientists have done much research on EMG control system. In this regard, feature extraction of EMG signal has been highly valued as a significant technique to extract the desired information of EMG signal and remove unnecessary parts. In this study, Wavelet Transform (WT has been applied as the main technique to extract Surface EMG (SEMG features because WT is consistent with the nature of EMG as a nonstationary signal. Furthermore, two evaluation criteria, namely, RES index (the ratio of a Euclidean distance to a standard deviation and scatter plot are recruited to investigate the efficiency of wavelet feature extraction. The results illustrated an improvement in class separability of hand movements in feature space. Accordingly, it has been shown that only the SEMG features extracted from first and second level of WT decomposition by second order of Daubechies family (db2 yielded the best class separability.

  8. CosmoQuest: A software platform for surface feature mapping

    Science.gov (United States)

    Gay, Pamela

    2016-07-01

    While many tools exist for allowing individuals to mark features in images, it has previously been unwieldy to get entire teams collaboratively mapping out surface features, and to statistically compare each team members contributions. Our CSB software was initially developed to facilitate crowd-sourcing projects, including CosmoQuest's "Moon Mappers" project. Statistically study of its results (Robbins et al 2014) has shown that professionals using this software get results that are as good as those they get using other commonly used software packages. This has lead to an expansion of the software to facilitate professional science use of the software. In order to allow the greatest use of CSB, and to facilitate better science collaboration, CosmoQuest now allows teams to create private projects. Basic features include: using their own data sets, allowing multiple team members to annotate the images, performing basic statistics on the resulting data, downloading all results in either .sql or .csv formats. In this presentation, we will overview how best to use CSB to improve your own science collaboration. Current applications include surface science and transient object identification, and published results include both crater maps and the discovery of KBOs.

  9. Spectral features in isolated neutron stars induced by inhomogeneous surface temperatures

    CERN Document Server

    Viganò, Daniele; Rea, Nanda; Pons, José A

    2014-01-01

    The thermal X-ray spectra of several isolated neutron stars display deviations from a pure blackbody. The accurate physical interpretation of these spectral features bears profound implications for our understanding of the atmospheric composition, magnetic field strength and topology, and equation of state of dense matter. With specific details varying from source to source, common explanations for the features have ranged from atomic transitions in the magnetized atmospheres or condensed surface, to cyclotron lines generated in a hot ionized layer near the surface. Here we quantitatively evaluate the X-ray spectral distortions induced by inhomogeneous temperature distributions of the neutron star surface. To this aim, we explore several surface temperature distributions, we simulate their corresponding general relativistic X-ray spectra (assuming an isotropic, blackbody emission), and fit the latter with a single blackbody model. We find that, in some cases, the presence of a spurious 'spectral line' is requ...

  10. Adaptive Dynamic Surface Control for Generator Excitation Control System

    Directory of Open Access Journals (Sweden)

    Zhang Xiu-yu

    2014-01-01

    Full Text Available For the generator excitation control system which is equipped with static var compensator (SVC and unknown parameters, a novel adaptive dynamic surface control scheme is proposed based on neural network and tracking error transformed function with the following features: (1 the transformation of the excitation generator model to the linear systems is omitted; (2 the prespecified performance of the tracking error can be guaranteed by combining with the tracking error transformed function; (3 the computational burden is greatly reduced by estimating the norm of the weighted vector of neural network instead of the weighted vector itself; therefore, it is more suitable for the real time control; and (4 the explosion of complicity problem inherent in the backstepping control can be eliminated. It is proved that the new scheme can make the system semiglobally uniformly ultimately bounded. Simulation results show the effectiveness of this control scheme.

  11. Surface and Volume Grid Generation in Parametric Form

    Science.gov (United States)

    Yu, Tzuyi; Soni, Bharat K.; Benjamin, Ted; Williams, Robert

    1996-01-01

    The algorithm for surface modeling and volume grid generation using parametric Non-Uniform Rational B-splines (NURBS) geometric representation are presented. The enhanced re-parameterization algorithm which can yield a desired physical distribution on the curve, surface, and volume is also presented. This approach bridges the gap between computer aided design surface/volume definition and surface/volume grid generation.

  12. 3D SURFACE GENERATION FROM AERIAL THERMAL IMAGERY

    Directory of Open Access Journals (Sweden)

    B. Khodaei

    2015-12-01

    Full Text Available Aerial thermal imagery has been recently applied to quantitative analysis of several scenes. For the mapping purpose based on aerial thermal imagery, high accuracy photogrammetric process is necessary. However, due to low geometric resolution and low contrast of thermal imaging sensors, there are some challenges in precise 3D measurement of objects. In this paper the potential of thermal video in 3D surface generation is evaluated. In the pre-processing step, thermal camera is geometrically calibrated using a calibration grid based on emissivity differences between the background and the targets. Then, Digital Surface Model (DSM generation from thermal video imagery is performed in four steps. Initially, frames are extracted from video, then tie points are generated by Scale-Invariant Feature Transform (SIFT algorithm. Bundle adjustment is then applied and the camera position and orientation parameters are determined. Finally, multi-resolution dense image matching algorithm is used to create 3D point cloud of the scene. Potential of the proposed method is evaluated based on thermal imaging cover an industrial area. The thermal camera has 640×480 Uncooled Focal Plane Array (UFPA sensor, equipped with a 25 mm lens which mounted in the Unmanned Aerial Vehicle (UAV. The obtained results show the comparable accuracy of 3D model generated based on thermal images with respect to DSM generated from visible images, however thermal based DSM is somehow smoother with lower level of texture. Comparing the generated DSM with the 9 measured GCPs in the area shows the Root Mean Square Error (RMSE value is smaller than 5 decimetres in both X and Y directions and 1.6 meters for the Z direction.

  13. Surface charge features of kaolinite particles and their interactions

    Science.gov (United States)

    Gupta, Vishal

    Kaolinite is both a blessing and a curse. As an important industrial mineral commodity, kaolinite clays are extensively used in the paper, ceramic, paint, plastic and rubber industries. In all these applications the wettability, aggregation, dispersion, flotation and thickening of kaolinite particles are affected by its crystal structure and surface properties. It is therefore the objective of this research to investigate selected physical and surface chemical properties of kaolinite, specifically the surface charge of kaolinite particles. A pool of advanced analytical techniques such as XRD, XRF, SEM, AFM, FTIR and ISS were utilized to investigate the morphological and surface chemistry features of kaolinite. Surface force measurements revealed that the silica tetrahedral face of kaolinite is negatively charged at pH>4, whereas the alumina octahedral face of kaolinite is positively charged at pH8. Based on electrophoresis measurements, the apparent iso-electric point for kaolinite particles was determined to be less than pH 3. In contrast, the point of zero charge was determined to be pH 4.5 by titration techniques, which corresponds to the iso-electric point of between pH 4 and 5 as determined by surface force measurements. Results from kaolinite particle interactions indicate that the silica face--alumina face interaction is dominant for kaolinite particle aggregation at low and intermediate pH values, which explains the maximum shear yield stress at pH 5-5.5. Lattice resolution images reveal the hexagonal lattice structure of these two face surfaces of kaolinite. Analysis of the silica face of kaolinite showed that the center of the hexagonal ring of oxygen atoms is vacant, whereas the alumina face showed that the hexagonal surface lattice ring of hydroxyls surround another hydroxyl in the center of the ring. High resolution transmission electron microscopy investigation of kaolinite has indicated that kaolinite is indeed composed of silica/alumina bilayers

  14. Analysis of EEG features of neuronal surface antibody associated encephalitis

    Directory of Open Access Journals (Sweden)

    Lu-hua WEI

    2016-09-01

    Full Text Available Objective To summarize the clinical manifestations, EEG and head MRI features of neuronal surface antibody associated encephalitis, and to investigate the role of EEG in determining the relapse or fluctuation of this disease, characteristics of EEG corresponding to head MRI, and EEG features in different clinical stages. Methods A total of 23 patients with neuronal surface antibody associated encephalitis were divided into ascent, climax, descent and recovery stage according to their clinical course. The relation between EEG background activity, distribution of slow wave, epileptiform discharge, extreme delta brush (EDB and relapse or fluctuation of the disease was analyzed. The relation between EEG features and head MRI abnormalities, and also EEG features in different stages were analyzed. Results There were 19 anti-N-methyl-D-aspartate (NMDA receptor encephalitis patients, 3 anti-leucine-rich glioma-inactivated 1 (LGI1 antibody associated encephalitis and one anti-γ-aminobutyric acid B receptor (GABABR antibody associated encephalitis. The frequencies of clinical presentations were psychological or cognitive dysfunction, epileptic seizure, conscious disturbance, speech dysfunction and movement disorder in descending order. Within 30.50 d from onset, 6 patients demonstrated slow wave background, of whom 2 relapsed or fluctuated; 5 patients had α rhythm background and none of them relapsed or fluctuated. In patients with anti-NMDA receptor encephalitis, the difference in first hospital stay (Z = -0.785, P = 0.433 and relapse or fluctuation (Fisher's exact probability: P = 0.155 between EDB group and non-EDB group was not significant. There was no apparent correlation between EEG background activities and head MRI abnormalities in different stages. In ascent and climax stage, EEG background activities were predominantly slow wave, and the distribution of slow wave was relatively broader. EEG background changed to α rhythm from descent stage

  15. Touching Textured Surfaces: Cells in Somatosensory Cortex Respond Both to Finger Movement and to Surface Features

    Science.gov (United States)

    Darian-Smith, Ian; Sugitani, Michio; Heywood, John; Karita, Keishiro; Goodwin, Antony

    1982-11-01

    Single neurons in Brodmann's areas 3b and 1 of the macaque postcentral gyrus discharge when the monkey rubs the contralateral finger pads across a textured surface. Both the finger movement and the spatial pattern of the surface determine this discharge in each cell. The spatial features of the surface are represented unambiguously only in the responses of populations of these neurons, and not in the responses of the constituent cells.

  16. Feature-preserving surface mesh smoothing via suboptimal Delaunay triangulation.

    Science.gov (United States)

    Gao, Zhanheng; Yu, Zeyun; Holst, Michael

    2013-01-01

    A method of triangular surface mesh smoothing is presented to improve angle quality by extending the original optimal Delaunay triangulation (ODT) to surface meshes. The mesh quality is improved by solving a quadratic optimization problem that minimizes the approximated interpolation error between a parabolic function and its piecewise linear interpolation defined on the mesh. A suboptimal problem is derived to guarantee a unique, analytic solution that is significantly faster with little loss in accuracy as compared to the optimal one. In addition to the quality-improving capability, the proposed method has been adapted to remove noise while faithfully preserving sharp features such as edges and corners of a mesh. Numerous experiments are included to demonstrate the performance of the method.

  17. Design of vector quantizer for image compression using self-organizing feature map and surface fitting.

    Science.gov (United States)

    Laha, Arijit; Pal, Nikhil R; Chanda, Bhabatosh

    2004-10-01

    We propose a new scheme of designing a vector quantizer for image compression. First, a set of codevectors is generated using the self-organizing feature map algorithm. Then, the set of blocks associated with each code vector is modeled by a cubic surface for better perceptual fidelity of the reconstructed images. Mean-removed vectors from a set of training images is used for the construction of a generic codebook. Further, Huffman coding of the indices generated by the encoder and the difference-coded mean values of the blocks are used to achieve better compression ratio. We proposed two indices for quantitative assessment of the psychovisual quality (blocking effect) of the reconstructed image. Our experiments on several training and test images demonstrate that the proposed scheme can produce reconstructed images of good quality while achieving compression at low bit rates. Index Terms-Cubic surface fitting, generic codebook, image compression, self-organizing feature map, vector quantization.

  18. Electron acceleration and high harmonic generation by relativistic surface plasmons

    Science.gov (United States)

    Cantono, Giada; Luca Fedeli Team; Andrea Sgattoni Team; Andrea Macchi Team; Tiberio Ceccotti Team

    2016-10-01

    Intense, short laser pulses with ultra-high contrast allow resonant surface plasmons (SPs) excitation on solid wavelength-scale grating targets, opening the way to the extension of Plasmonics in the relativistic regime and the manipulation of intense electromagnetic fields to develop new short, energetic, laser-synchronized radiation sources. Recent theoretical and experimental studies have explored the role of SP excitation in increasing the laser-target coupling and enhancing ion acceleration, high-order harmonic generation and surface electron acceleration. Here we present our results on SP driven electron acceleration from grating targets at ultra-high laser intensities (I = 5 ×1019 W/cm2, τ = 25 fs). When the resonant condition for SP excitation is fulfilled, electrons are emitted in a narrow cone along the target surface, with a total charge of about 100 pC and energy spectra peaked around 5 MeV. Distinguishing features of the resonant process were investigated by varying the incidence angle, grating type and with the support of 3D PIC simulations, which closely reproduced the experimental data. Open challenges and further measurements on high-order harmonic generation in presence of a relativistic SP will also be discussed.

  19. Some features of generation of spoke-shaped neodyminum lasers

    Energy Technology Data Exchange (ETDEWEB)

    Dzhibladze, M.I.; Lazarev, L.E.

    1982-08-01

    Experimental results are presented on the generation properties of spoke-shaped neodymium lasers in the periodic giant pulse regime. In lasers with polished end-faces, two types of pulses were observed, corresponding to longitudinal and circular types of oscillation. It is shown that the energetic characteristics of generation in spoke-shaped neodymium lasers improve greatly when circular types of oscillation are suppressed.

  20. Generalised Brown Clustering and Roll-up Feature Generation

    DEFF Research Database (Denmark)

    Derczynski, Leon; Chester, Sean

    2016-01-01

    Brown clustering is an established technique, used in hundreds of computational linguistics papers each year, to group word types that have similar distributional information. It is unsupervised and can be used to create powerful word representations for machine learning. Despite its improbable...... success relative to more complex methods, few have investigated whether Brown clustering has really been applied optimally. In this paper, we present a subtle but profound generalisation of Brown clustering to improve the overall quality by decoupling the number of output classes from the computational...... active set size. Moreover, the generalisation permits a novel approach to feature selection from Brown clusters: We show that the standard approach of shearing the Brown clustering output tree at arbitrary bitlengths is lossy and that features should be chosen instead by rolling up Generalised Brown...

  1. N-sided Surface Generation from Arbitrary Boundary Edges

    Science.gov (United States)

    2000-01-01

    Such surfaces are generally classified as transfinite surfaces, in which a surface is interpolated to span given curves. In the proposed method...the 3D space. Sabin calls the method of surface generation from boundary edges a " transfinite surface" in contrast with the one which is characterized...vectors. Thus, the surface is a transfinite surface in consideration of the boundary positions and cross-boundary derivatives on the given boundary

  2. Automatic generation of Chinese character using features fusion from calligraphy and font

    Science.gov (United States)

    Shi, Cao; Xiao, Jianguo; Xu, Canhui; Jia, Wenhua

    2014-02-01

    A spatial statistic based contour feature representation is proposed to achieve extraction of local contour feature from Chinese calligraphy character, and a features fusion strategy is designed to automatically generate new hybrid character, making well use of contour feature of calligraphy and structural feature of font. The features fusion strategy employs dilation and erosion operations iteratively to inject the extracted contour feature from Chinese calligraphy into font, which are similar to "pad" and "cut" in a sculpture progress. Experimental results demonstrate that the generated new hybrid character hold both contour feature of calligraphy and structural feature of font. Especially, two kinds of Chinese calligraphy skills called "Fei Bai" and "Zhang Mo" are imitated in the hybrid character. "Fei Bai" depicts a phenomenon that part of a stroke fade out due to the fast movement of hair brush or the lack of ink, and "Zhang Mo" describes a condition that hair brush holds so much ink that strokes overlap.

  3. Triangle geometry processing for surface modeling and cartesian grid generation

    Science.gov (United States)

    Aftosmis, Michael J [San Mateo, CA; Melton, John E [Hollister, CA; Berger, Marsha J [New York, NY

    2002-09-03

    Cartesian mesh generation is accomplished for component based geometries, by intersecting components subject to mesh generation to extract wetted surfaces with a geometry engine using adaptive precision arithmetic in a system which automatically breaks ties with respect to geometric degeneracies. During volume mesh generation, intersected surface triangulations are received to enable mesh generation with cell division of an initially coarse grid. The hexagonal cells are resolved, preserving the ability to directionally divide cells which are locally well aligned.

  4. On features ov vacancies generation at low temperature

    CERN Document Server

    Magomedov, M N

    2001-01-01

    The expressions for calculating the thermodynamic potential, enthalpy, entropy (s subnu) and vacancies generation volume in the simple matter crystal at the temperatures close to 0 K are obtained. It is established that the vacancies concentration (PHI) as the temperature function (T) has the minimum by the certain T sub 0 value. The PHI(T) function by T < T sub 0 increases with decrease in T, therefore by T sub 0 the s subnu(T) function changes its sign, and by T < T sub 0 the s subnu-value becomes negative. It is shown that availability of the zero vacancies does not violate the third principle of thermodynamics

  5. GENERATE TRIANGULATED SURFACES FROM MASSIVE UNORGANIZED POINTS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A region-growing method for reconstructing triangulated surfaces from massive unorganized points is presented. To save memory space, a ring data-structure is adopted to build connections between points and triangulated surfaces. The data-structure allows the efficient retrieval of all neighboring vertices and triangles of a given vertice. To narrow the search range of adjacent points and avoid triangle intersection, an influence area is defined for each active-edge. In the region-growing process of triangulated surfaces, a minimum-edge-angle-product algorithm is put forward to select an appropriate point to form a new triangle for an active edge. Results indicate that the presented method has high efficiency and needs less memory space, optimized triangulated surfaces with reliable topological quality can be obtained after triangulation.

  6. Combination of 3D skin surface texture features and 2D ABCD features for improved melanoma diagnosis.

    Science.gov (United States)

    Ding, Yi; John, Nigel W; Smith, Lyndon; Sun, Jiuai; Smith, Melvyn

    2015-10-01

    Two-dimensional asymmetry, border irregularity, colour variegation and diameter (ABCD) features are important indicators currently used for computer-assisted diagnosis of malignant melanoma (MM); however, they often prove to be insufficient to make a convincing diagnosis. Previous work has demonstrated that 3D skin surface normal features in the form of tilt and slant pattern disruptions are promising new features independent from the existing 2D ABCD features. This work investigates that whether improved lesion classification can be achieved by combining the 3D features with the 2D ABCD features. Experiments using a nonlinear support vector machine classifier show that many combinations of the 2D ABCD features and the 3D features can give substantially better classification accuracy than using (1) single features and (2) many combinations of the 2D ABCD features. The best 2D and 3D feature combination includes the overall 3D skin surface disruption, the asymmetry and all the three colour channel features. It gives an overall 87.8 % successful classification, which is better than the best single feature with 78.0 % and the best 2D feature combination with 83.1 %. These demonstrate that (1) the 3D features have additive values to improve the existing lesion classification and (2) combining the 3D feature with all the 2D features does not lead to the best lesion classification. The two ABCD features not selected by the best 2D and 3D combination, namely (1) the border feature and (2) the diameter feature, were also studied in separate experiments. It found that inclusion of either feature in the 2D and 3D combination can successfully classify 3 out of 4 lesion groups. The only one group not accurately classified by either feature can be classified satisfactorily by the other. In both cases, they have shown better classification performances than those without the 3D feature in the combinations. This further demonstrates that (1) the 3D feature can be used to

  7. An Efficient Algorithm for Surface Generation

    CERN Document Server

    Samuelsson, C

    1995-01-01

    A method is given that "inverts" a logic grammar and displays it from the point of view of the logical form, rather than from that of the word string. LR-compiling techniques are used to allow a recursive-descent generation algorithm to perform "functor merging" much in the same way as an LR parser performs prefix merging. This is an improvement on the semantic-head-driven generator that results in a much smaller search space. The amount of semantic lookahead can be varied, and appropriate tradeoff points between table size and resulting nondeterminism can be found automatically.

  8. Secured Cryptographic Key Generation From Multimodal Biometrics Feature Level Fusion Of Fingerprint And Iris

    CERN Document Server

    Jagadeesan, A

    2010-01-01

    Human users have a tough time remembering long cryptographic keys. Hence, researchers, for so long, have been examining ways to utilize biometric features of the user instead of a memorable password or passphrase, in an effort to generate strong and repeatable cryptographic keys. Our objective is to incorporate the volatility of the users biometric features into the generated key, so as to make the key unguessable to an attacker lacking significant knowledge of the users biometrics. We go one step further trying to incorporate multiple biometric modalities into cryptographic key generation so as to provide better security. In this article, we propose an efficient approach based on multimodal biometrics (Iris and fingerprint) for generation of secure cryptographic key. The proposed approach is composed of three modules namely, 1) Feature extraction, 2) Multimodal biometric template generation and 3) Cryptographic key generation. Initially, the features, minutiae points and texture properties are extracted from...

  9. Secured Cryptographic Key Generation From Multimodal Biometrics: Feature Level Fusion of Fingerprint and Iris

    CERN Document Server

    Jagadeesan, A

    2010-01-01

    Human users have a tough time remembering long cryptographic keys. Hence, researchers, for so long, have been examining ways to utilize biometric features of the user instead of a memorable password or passphrase, in an effort to generate strong and repeatable cryptographic keys. Our objective is to incorporate the volatility of the user's biometric features into the generated key, so as to make the key unguessable to an attacker lacking significant knowledge of the user's biometrics. We go one step further trying to incorporate multiple biometric modalities into cryptographic key generation so as to provide better security. In this article, we propose an efficient approach based on multimodal biometrics (Iris and fingerprint) for generation of secure cryptographic key. The proposed approach is composed of three modules namely, 1) Feature extraction, 2) Multimodal biometric template generation and 3) Cryptographic key generation. Initially, the features, minutiae points and texture properties are extracted fr...

  10. A TECHNIQUE OF DIGITAL SURFACE MODEL GENERATION

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    It is usually a time-consuming process to real-time set up 3D digital surface mo del(DSM) of an object with complex sur face.On the basis of the architectural survey proje ct of“Chilin Nunnery Reconstruction",this paper investigates an easy and feasi ble way,that is,on project site,applying digital close range photogrammetry an d CAD technique to establish the DSM for simulating ancient architectures with c omplex surface.The method has been proved very effective in practice.

  11. An automated pipeline for cortical surface generation and registration of the cerebral cortex

    Science.gov (United States)

    Li, Wen; Ibanez, Luis; Gelas, Arnaud; Yeo, B. T. Thomas; Niethammer, Marc; Andreasen, Nancy C.; Magnotta, Vincent A.

    2011-03-01

    The human cerebral cortex is one of the most complicated structures in the body. It has a highly convoluted structure with much of the cortical sheet buried in sulci. Based on cytoarchitectural and functional imaging studies, it is possible to segment the cerebral cortex into several subregions. While it is only possible to differentiate the true anatomical subregions based on cytoarchitecture, the surface morphometry aligns closely with the underlying cytoarchitecture and provides features that allow the surface of the cortex to be parcellated based on the sulcal and gyral patterns that are readily visible on the MR images. We have developed a fully automated pipeline for the generation and registration of cortical surfaces in the spherical domain. The pipeline initiates with the BRAINS AutoWorkup pipeline. Subsequently, topology correction and surface generation is performed to generate a genus zero surface and mapped to a sphere. Several surface features are then calculated to drive the registration between the atlas surface and other datasets. A spherical diffeomorphic demons algorithm is used to co-register an atlas surface onto a subject surface. A lobar based atlas of the cerebral cortex was created from a manual parcellation of the cortex. The atlas surface was then co-registered to five additional subjects using a spherical diffeomorphic demons algorithm. The labels from the atlas surface were warped on the subject surface and compared to the manual raters. The average Dice overlap index was 0.89 across all regions.

  12. Generating arbitrary ultrasound fields with tailored optoacoustic surface profiles

    Science.gov (United States)

    Brown, M. D.; Nikitichev, D. I.; Treeby, B. E.; Cox, B. T.

    2017-02-01

    Acoustic fields with multiple foci have many applications in physical acoustics ranging from particle manipulation to neural modulation. However, the generation of multiple foci at arbitrary locations in three-dimensional is challenging using conventional transducer technology. In this work, the optical generation of acoustic fields focused at multiple points using a single optical pulse is demonstrated. This is achieved using optically absorbing surface profiles designed to generate specific, user-defined, wavefields. An optimisation approach for the design of these tailored surface profiles is developed. This searches for a smoothly varying surface that will generate a high peak pressure at a set of target focal points. The designed surface profiles are then realised via a combination of additive manufacturing and absorber deposition techniques. Acoustic field measurements from a sample designed to generate the numeral "7" are used to demonstrate the design method.

  13. Extraction of surface-related features in a recurrent model of V1-V2 interactions.

    Directory of Open Access Journals (Sweden)

    Ulrich Weidenbacher

    Full Text Available BACKGROUND: Humans can effortlessly segment surfaces and objects from two-dimensional (2D images that are projections of the 3D world. The projection from 3D to 2D leads partially to occlusions of surfaces depending on their position in depth and on viewpoint. One way for the human visual system to infer monocular depth cues could be to extract and interpret occlusions. It has been suggested that the perception of contour junctions, in particular T-junctions, may be used as cue for occlusion of opaque surfaces. Furthermore, X-junctions could be used to signal occlusion of transparent surfaces. METHODOLOGY/PRINCIPAL FINDINGS: In this contribution, we propose a neural model that suggests how surface-related cues for occlusion can be extracted from a 2D luminance image. The approach is based on feedforward and feedback mechanisms found in visual cortical areas V1 and V2. In a first step, contours are completed over time by generating groupings of like-oriented contrasts. Few iterations of feedforward and feedback processing lead to a stable representation of completed contours and at the same time to a suppression of image noise. In a second step, contour junctions are localized and read out from the distributed representation of boundary groupings. Moreover, surface-related junctions are made explicit such that they are evaluated to interact as to generate surface-segmentations in static images. In addition, we compare our extracted junction signals with a standard computer vision approach for junction detection to demonstrate that our approach outperforms simple feedforward computation-based approaches. CONCLUSIONS/SIGNIFICANCE: A model is proposed that uses feedforward and feedback mechanisms to combine contextually relevant features in order to generate consistent boundary groupings of surfaces. Perceptually important junction configurations are robustly extracted from neural representations to signal cues for occlusion and transparency. Unlike

  14. Circular arc snakes and kinematic surface generation

    KAUST Repository

    Barton, Michael

    2013-05-01

    We discuss the theory, discretization, and numerics of curves which are evolving such that part of their shape, or at least their curvature as a function of arc length, remains unchanged. The discretization of a curve as a smooth sequence of circular arcs is well suited for such purposes, and allows us to reduce evolution of curves to the evolution of a control point collection in a certain finite-dimensional shape space. We approach this evolution by a 2-step process: linearized evolution via optimized velocity fields, followed by optimization in order to exactly fulfill all geometric side conditions. We give applications to freeform architecture, including "rationalization" of a surface by congruent arcs, form finding and, most interestingly, non-static architecture. © 2013 The Author(s) Computer Graphics Forum © 2013 The Eurographics Association and Blackwell Publishing Ltd.

  15. Contributions of feature shapes and surface cues to the recognition and neural representation of facial identity.

    Science.gov (United States)

    Andrews, Timothy J; Baseler, Heidi; Jenkins, Rob; Burton, A Mike; Young, Andrew W

    2016-10-01

    A full understanding of face recognition will involve identifying the visual information that is used to discriminate different identities and how this is represented in the brain. The aim of this study was to explore the importance of shape and surface properties in the recognition and neural representation of familiar faces. We used image morphing techniques to generate hybrid faces that mixed shape properties (more specifically, second order spatial configural information as defined by feature positions in the 2D-image) from one identity and surface properties from a different identity. Behavioural responses showed that recognition and matching of these hybrid faces was primarily based on their surface properties. These behavioural findings contrasted with neural responses recorded using a block design fMRI adaptation paradigm to test the sensitivity of Haxby et al.'s (2000) core face-selective regions in the human brain to the shape or surface properties of the face. The fusiform face area (FFA) and occipital face area (OFA) showed a lower response (adaptation) to repeated images of the same face (same shape, same surface) compared to different faces (different shapes, different surfaces). From the behavioural data indicating the critical contribution of surface properties to the recognition of identity, we predicted that brain regions responsible for familiar face recognition should continue to adapt to faces that vary in shape but not surface properties, but show a release from adaptation to faces that vary in surface properties but not shape. However, we found that the FFA and OFA showed an equivalent release from adaptation to changes in both shape and surface properties. The dissociation between the neural and perceptual responses suggests that, although they may play a role in the process, these core face regions are not solely responsible for the recognition of facial identity.

  16. Feature-based handling of surface faults in compact disc players

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle

    2006-01-01

    In this paper a novel method called feature-based control is presented. The method is designed to improve compact disc players’ handling of surface faults on the discs. The method is based on a fault-tolerant control scheme, which uses extracted features of the surface faults to remove those from...... the detector signals used for control during the occurrence of surface faults. The extracted features are coefficients of Karhunen–Loève approximations of the surface faults. The performance of the feature-based control scheme controlling compact disc players playing discs with surface faults has been...

  17. Features of molten pool free surface in laser processing

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    On the basis of static characteristics of free surface of molten pools in laser processing, starting with the change of surface tension, the uniform numerical models are developed for both the liquid and solid regions of metals by applying the enthalpy source method and the porous region model. The flow and heat transfer characteristics in the molten pools and the distribution of surface tension on free surface are disclosed. The shape of free surface is analyzed by considering the static forces on the free surface and by combining with the calculated results of the molten pool. The model is applied to analyzing the laser processing of AISI 304 stainless steel, and the effects of different processing tech nics and material properties on shaping of free surface are discussed.

  18. Wave Generated by the NACA4412 Hydrofoil near Free Surface

    Directory of Open Access Journals (Sweden)

    Hassan Ghassemi

    2013-01-01

    Full Text Available The generation of wave due to moving hydrofoil in steady streams close to a free surface is presented. The potential-based boundary element method is employed to the NACA4412 hydrofoil with linearized dynamic and kinematic boundary conditions on the free surface. The perturbation velocity potential is calculated using the Green formulation and Kutta condition. The numerical results of waves generated by the hydrofoil are presented and discussed at various Froude numbers and immersion depths.

  19. Feature selective temporal prediction of Alzheimer's disease progression using hippocampus surface morphometry

    National Research Council Canada - National Science Library

    Tsao, Sinchai; Gajawelli, Niharika; Zhou, Jiayu; Shi, Jie; Ye, Jieping; Wang, Yalin; Leporé, Natasha

    2017-01-01

    In this work, we present our results of using machine learning to predict temporal behavior changes in Alzheimers Disease using entire topological feature maps of the hippocampus surface (2100 feature points...

  20. Brain segmentation and the generation of cortical surfaces

    Science.gov (United States)

    Joshi, M.; Cui, J.; Doolittle, K.; Joshi, S.; Van Essen, D.; Wang, L.; Miller, M. I.

    1999-01-01

    This paper describes methods for white matter segmentation in brain images and the generation of cortical surfaces from the segmentations. We have developed a system that allows a user to start with a brain volume, obtained by modalities such as MRI or cryosection, and constructs a complete digital representation of the cortical surface. The methodology consists of three basic components: local parametric modeling and Bayesian segmentation; surface generation and local quadratic coordinate fitting; and surface editing. Segmentations are computed by parametrically fitting known density functions to the histogram of the image using the expectation maximization algorithm [DLR77]. The parametric fits are obtained locally rather than globally over the whole volume to overcome local variations in gray levels. To represent the boundary of the gray and white matter we use triangulated meshes generated using isosurface generation algorithms [GH95]. A complete system of local parametric quadratic charts [JWM+95] is superimposed on the triangulated graph to facilitate smoothing and geodesic curve tracking. Algorithms for surface editing include extraction of the largest closed surface. Results for several macaque brains are presented comparing automated and hand surface generation. Copyright 1999 Academic Press.

  1. Identification of natural images and computer-generated graphics based on statistical and textural features.

    Science.gov (United States)

    Peng, Fei; Li, Jiao-ting; Long, Min

    2015-03-01

    To discriminate the acquisition pipelines of digital images, a novel scheme for the identification of natural images and computer-generated graphics is proposed based on statistical and textural features. First, the differences between them are investigated from the view of statistics and texture, and 31 dimensions of feature are acquired for identification. Then, LIBSVM is used for the classification. Finally, the experimental results are presented. The results show that it can achieve an identification accuracy of 97.89% for computer-generated graphics, and an identification accuracy of 97.75% for natural images. The analyses also demonstrate the proposed method has excellent performance, compared with some existing methods based only on statistical features or other features. The method has a great potential to be implemented for the identification of natural images and computer-generated graphics. © 2014 American Academy of Forensic Sciences.

  2. Integration of Urban Features into a Coupled Groundwater-Surface Water Model

    Science.gov (United States)

    Bhaskar, A. S.; Welty, C.; Maxwell, R. M.

    2012-12-01

    To better understand the feedbacks between urban development and water availability, we are coupling an integrated hydrologic model with an urban growth model, both of the Baltimore, Maryland, USA region. The urban growth model SLEUTH has been calibrated, validated and run by collaborators at Shippensburg University. We are using ParFlow.CLM as the integrated hydrologic model. This model is applied to the 13,000 sq. km. Baltimore metropolitan area, which spans the Gunpowder and Patapsco watersheds. The model domain includes both Piedmont and Coastal Plain physiographic provinces. We have incorporated characteristics of both the natural hydrogeologic system and the superimposed urban environment. Standard hydrogeologic information such as hydraulic conductivity of fractured bedrock, Coastal Plain sediments, and surficial soils, as well as saprolite thickness, porosity, and specific storage properties have been included. We have also quantified a number of aspects representing urban development, such as residential and municipal well pumping, municipal reservoir use, lawn watering, and water supply pipe leakage estimates. We have represented impervious surface coverage using low surface hydraulic conductivity values. The land surface fluxes in CLM (Common Land Model) use surface land cover and therefore represent reduced evapotranspiration in urban areas. A study of urban and natural watershed inflows and inflows in this region indicated some urban features significantly modify catchment water balances. We are particularly interested in the effects of these urban hydrologic features on groundwater recharge in the Baltimore area. Prior to inclusion of subsurface heterogeneity, we initialized the model by running it hourly from 2000 to 2007. The initialization was generated by a dynamic spin-up process, using the UMBC High Performance Computing Facility. Observed meteorological forcing, such as hourly precipitation and air temperature, are used by the land surface

  3. Second harmonic generation spectroscopy on Si surfaces and interfaces

    DEFF Research Database (Denmark)

    Pedersen, Kjeld

    2010-01-01

    Optical second harmonic generation (SHG) spectroscopy studies of Si(111) surfaces and interfaces are reviewed for two types of systems: (1) clean 7 x 7 and root 3 x root 3-Ag reconstructed surfaces prepared under ultra-high vacuum conditions where surface states are excited and (2) interfaces......-like interband transitions that can be referred to excitations of dangling bond surface states. Adsorption of oxygen leads to formation of a new surface resonance. Such resonances appearing in the region between the bulk critical points E-1 and E-2 are also shown to be important for Si/oxide interfaces in SOI...

  4. Airfoil Trailing Edge Noise Generation and Its Surface Pressure Fluctuation

    DEFF Research Database (Denmark)

    Zhu, Wei Jun; Shen, Wen Zhong

    2015-01-01

    In the present work, Large Eddy Simulation (LES) of turbulent flows over a NACA 0015 airfoil is performed. The purpose of such numerical study is to relate the aerodynamic surface pressure with the noise generation. The results from LES are validated against detailed surface pressure measurements...

  5. Research on Wind Turbine Generator Dynamic Reliability Test System Based on Feature Recognition

    Directory of Open Access Journals (Sweden)

    Bin Wang

    2013-09-01

    Full Text Available Wind power resource development is increasingly becoming the focus of the current research and development in various countries' relevant scientific institutions. To make sure the secure and reliable operation of wind turbine generator, the study develops the wind turbine generator dynamic reliability test system. When the fault of gearbox and spindle occurs, their features of vibration signals are special. According to the feature recognition technology, the application of time and frequency domain model identification method has practical significance to the test system. Based on Bayesian network fault diagnosis method, the vibration feature recognition system of wind turbine generator is constructed. Finally, the paper uses GPRS technology to realize the wireless transmission of operation information. The wind turbine generator dynamic reliability test system is built based on GPRS technology to realize automatic control and remote intelligent monitoring and to ensure the safe and stable operation of wind farms.

  6. STUDY ON THE GENERATION OF SOME BLENDING SURFACES

    Directory of Open Access Journals (Sweden)

    Drăgan Florin

    2009-07-01

    Full Text Available In this paper, using the blending (Coons method, we generate some families of free-form surfaces feasible in civil engineering, industries of airplanes, ships, automobiles, industrial and artistic objects, scientific researches and others. The possibility of designing free-form surfaces with the aid of computers has led to new methods for defining surfaces of the following types: Bezier [3], spline [3], Shepard [13], blending (Coons and Gordon [8], [3] and others.

  7. Generation and near-field imaging of Airy surface plasmons

    CERN Document Server

    Minovich, Alexander; Janunts, Norik; Pertsch, Thomas; Neshev, Dragomir N; Kivshar, Yuri S

    2011-01-01

    We demonstrate experimentally the generation and near-field imaging of nondiffracting surface waves - plasmonic Airy beams, propagating on the surface of a gold metal film. The Airy plasmons are excited by an engineered nanoscale phase grating, and demonstrate significant beam bending over their propagation. We show that the observed Airy plasmons exhibit self-healing properties, suggesting novel applications in plasmonic circuitry and surface optical manipulation.

  8. Feature-Adaptive Rendering of Loop Subdivision Surfaces on Modern GPUs

    Institute of Scientific and Technical Information of China (English)

    黄韵岑; 冯结青; 崔元敏; 杨宝光

    2014-01-01

    We present a novel approach for real-time rendering Loop subdivision surfaces on modern graphics hardware. Our algorithm evaluates both positions and normals accurately, thus providing the true Loop subdivision surface. The core idea is to recursively refine irregular patches using a GPU compute kernel. All generated regular patches are then directly evaluated and rendered using the hardware tessellation unit. Our approach handles triangular control meshes of arbitrary topologies and incorporates common subdivision surface features such as semi-sharp creases and hierarchical edits. While surface rendering is accurate up to machine precision, we also enforce a consistent bitwise evaluation of positions and normals at patch boundaries. This is particularly useful in the context of displacement mapping which strictly requires matching surface normals. Furthermore, we incorporate efficient level-of-detail rendering where subdivision depth and tessellation density can be adjusted on-the-fly. Overall, our algorithm provides high-quality results at real-time frame rates, thus being ideally suited to interactive rendering applications such as video games or authoring tools.

  9. Modulation of photoacoustic signal generation from metallic surfaces

    Science.gov (United States)

    Mitcham, Trevor; Homan, Kimberly; Frey, Wolfgang; Chen, Yun-Sheng; Emelianov, Stanislav; Hazle, John; Bouchard, Richard

    2013-05-01

    The ability to image metallic implants is important for medical applications ranging from diagnosis to therapy. Photoacoustic (PA) imaging has been recently pursued as a means to localize metallic implants in soft tissue. The work presented herein investigates different mechanisms to modulate the PA signal generated by macroscopic metallic surfaces. Wires of five different metals are tested to simulate medical implants/tools, while surface roughness is altered or physical vapor deposition (PVD) coatings are added to change the wires' overall optical absorption. PA imaging data of the wires are acquired at 970 nm. Results indicate that PA signal generation predominately occurs in a wire's metallic surface and not its aqueous surroundings. PA signal generation is similar for all metals tested, while addition of PVD coatings offers significant modulations (i.e., 4-dB enhancement and 26-dB reduction achieved) in PA signal generation. Results also suggest that PA signal increases with increasing surface roughness. Different coating and roughness schemes are then successfully utilized to generate spatial PA signal patterns. This work demonstrates the potential of surface modifications to enhance or reduce PA signal generation to permit improved PA imaging of implants/tools (i.e., providing location/orientation information) or to allow PA imaging of surrounding tissue.

  10. Algebraic surface grid generation in three-dimensional space

    Science.gov (United States)

    Warsi, Saif

    1992-01-01

    An interactive program for algebraic generation of structured surface grids in three dimensional space was developed on the IRIS4D series workstations. Interactive tools are available to ease construction of edge curves and surfaces in 3-D space. Addition, removal, or redistribution of points at arbitrary locations on a general 3-D surface or curve is possible. Also, redistribution of surface grid points may be accomplished through use of conventional surface splines or a method called 'surface constrained transfinite interpolation'. This method allows the user to redistribute the grid points on the edges of a surface patch; the effect of the redistribution is then propagated to the remainder of the surface through a transfinite interpolation procedure where the grid points will be constrained to lie on the surface. The program was written to be highly functional and easy to use. A host of utilities are available to ease the grid generation process. Generality of the program allows the creation of single and multizonal surface grids according to the user requirements. The program communicates with the user through popup menus, windows, and the mouse.

  11. Recent applications of liquid metals featuring nanoscale surface oxides

    Science.gov (United States)

    Neumann, Taylor V.; Dickey, Michael D.

    2016-05-01

    This proceeding describes recent efforts from our group to control the shape and actuation of liquid metal. The liquid metal is an alloy of gallium and indium which is non-toxic, has negligible vapor pressure, and develops a thin, passivating surface oxide layer. The surface oxide allows the liquid metal to be patterned and shaped into structures that do not minimize interfacial energy. The surface oxide can be selectively removed by changes in pH or by applying a voltage. The surface oxide allows the liquid metal to be 3D printed to form free-standing structures. It also allows for the liquid metal to be injected into microfluidic channels and to maintain its shape within the channels. The selective removal of the oxide results in drastic changes in surface tension that can be used to control the flow behavior of the liquid metal. The metal can also wet thin, solid films of metal that accelerates droplets of the liquid along the metal traces .Here we discuss the properties and applications of liquid metal to make soft, reconfigurable electronics.

  12. Featuring the nucleosome surface as a therapeutic target.

    Science.gov (United States)

    da Silva, Isabel Torres Gomes; de Oliveira, Paulo Sergio Lopes; Santos, Guilherme Martins

    2015-05-01

    Chromatin is the major regulator of gene expression and genome maintenance. Proteins that bind the nucleosome, the repetitive unit of chromatin, and the histone H4 tail are critical to establishing chromatin architecture and phenotypic outcomes. Intriguingly, nucleosome-binding proteins (NBPs) and the H4 tail peptide compete for the same binding site at an acidic region on the nucleosome surface. Although the essential facts about the nucleosome were revealed 17 years ago, new insights into its atomic structure and molecular mechanisms are still emerging. Several complex nucleosome:NBP structures were recently revealed, characterizing the NBP-binding sites on the nucleosome surface. Here we discuss the potential of the nucleosome surface as a therapeutic target and the impact and development of exogenous nucleosome-binding molecules (eNBMs).

  13. Features of surface topography and the geological activity of Pluto

    Science.gov (United States)

    Vidmachenko, A. P.

    2016-05-01

    According to the data "New Horizons" of the spacecraft, researchers were able to specify the diameter of Pluto-2374 km. Its surface temperature in the equatorial region varies from 33 to 55 K over the planet's orbital period around the Sun in ~248 years. Presumably the surface of Pluto has a rocky base covered with a mantle of water ice, of frozen methane, nitrogen, ammonia and CO. Due to the large eccentricity of the orbit of Pluto, as it approaches the Sun, the ice melts, and the atmosphere is formed mainly of nitrogen and methane; while removing of the planet from the Sun - the atmosphere freezes out again.

  14. Generation of gear tooth surfaces by application of CNC machines

    Science.gov (United States)

    Litvin, F. L.; Chen, N. X.

    1994-01-01

    This study will demonstrate the importance of application of computer numerically controlled (CNC) machines in generation of gear tooth surfaces with new topology. This topology decreases gear vibration and will extend the gear capacity and service life. A preliminary investigation by a tooth contact analysis (TCA) program has shown that gear tooth surfaces in line contact (for instance, involute helical gears with parallel axes, worm gear drives with cylindrical worms, etc.) are very sensitive to angular errors of misalignment that cause edge contact and an unfavorable shape of transmission errors and vibration. The new topology of gear tooth surfaces is based on the localization of bearing contact, and the synthesis of a predesigned parabolic function of transmission errors that is able to absorb a piecewise linear function of transmission errors caused by gear misalignment. The report will describe the following topics: description of kinematics of CNC machines with six degrees of freedom that can be applied for generation of gear tooth surfaces with new topology. A new method for grinding of gear tooth surfaces by a cone surface or surface of revolution based on application of CNC machines is described. This method provides an optimal approximation of the ground surface to the given one. This method is especially beneficial when undeveloped ruled surfaces are to be ground. Execution of motions of the CNC machine is also described. The solution to this problem can be applied as well for the transfer of machine tool settings from a conventional generator to the CNC machine. The developed theory required the derivation of a modified equation of meshing based on application of the concept of space curves, space curves represented on surfaces, geodesic curvature, surface torsion, etc. Condensed information on these topics of differential geometry is provided as well.

  15. GridTool: A surface modeling and grid generation tool

    Science.gov (United States)

    Samareh-Abolhassani, Jamshid

    1995-01-01

    GridTool is designed around the concept that the surface grids are generated on a set of bi-linear patches. This type of grid generation is quite easy to implement, and it avoids the problems associated with complex CAD surface representations and associated surface parameterizations. However, the resulting surface grids are close to but not on the original CAD surfaces. This problem can be alleviated by projecting the resulting surface grids onto the original CAD surfaces. GridTool is designed primary for unstructured grid generation systems. Currently, GridTool supports VGRID and FELISA systems, and it can be easily extended to support other unstructured grid generation systems. The data in GridTool is stored parametrically so that once the problem is set up, one can modify the surfaces and the entire set of points, curves and patches will be updated automatically. This is very useful in a multidisciplinary design and optimization process. GridTool is written entirely in ANSI 'C', the interface is based on the FORMS library, and the graphics is based on the GL library. The code has been tested successfully on IRIS workstations running IRIX4.0 and above. The memory is allocated dynamically, therefore, memory size will depend on the complexity of geometry/grid. GridTool data structure is based on a link-list structure which allows the required memory to expand and contract dynamically according to the user's data size and action. Data structure contains several types of objects such as points, curves, patches, sources and surfaces. At any given time, there is always an active object which is drawn in magenta, or in their highlighted colors as defined by the resource file which will be discussed later.

  16. Upwelling filaments are cold, typically narrow features in surface ...

    African Journals Online (AJOL)

    spamer

    strong offshore flows and often terminate in eddy-like structures ... model initiated with observed velocity profiles. Mc-. Creary et al. ... These are a forced equatorward flow at the surface ...... 1991 — Dynamical simulations of filament formation and evolution in ... MOOERS, C. N. K. and A. R. ROBINSON 1984 — Turbulent jets.

  17. The Surface Features of Four Microcomputer Reading Programs.

    Science.gov (United States)

    Bradley, Virginia N.

    1984-01-01

    Uses the Bradley Inventory of Reading Comprehension Software to evaluate surface characteristics (including documentation and instructional design) of microcomputer reading comprehension programs produced by Scott Foresman, Random House, Control Data Corporation, and Basic Learning Systems. All four programs received high scores, but the Scott…

  18. FEATURES OF GEODEFORMATION CHANGES OF NEAR SURFACE SEDIMENTARY ROCKS

    Directory of Open Access Journals (Sweden)

    I. A. Larionov

    2016-11-01

    Full Text Available The results of investigations of the deformation process in the near surface sedimentary rocks, which has been carried out in a seismically active region of Kamchatka peninsular since 2007,are presented. The peculiarity of the experiments on the registration of geodeformations is the application of a laser deformograph-interferometer constructed according to the Michelson interferometer scheme.

  19. A new method to extract stable feature points based on self-generated simulation images

    Science.gov (United States)

    Long, Fei; Zhou, Bin; Ming, Delie; Tian, Jinwen

    2015-10-01

    Recently, image processing has got a lot of attention in the field of photogrammetry, medical image processing, etc. Matching two or more images of the same scene taken at different times, by different cameras, or from different viewpoints, is a popular and important problem. Feature extraction plays an important part in image matching. Traditional SIFT detectors reject the unstable points by eliminating the low contrast and edge response points. The disadvantage is the need to set the threshold manually. The main idea of this paper is to get the stable extremums by machine learning algorithm. Firstly we use ASIFT approach coupled with the light changes and blur to generate multi-view simulated images, which make up the set of the simulated images of the original image. According to the way of generating simulated images set, affine transformation of each generated image is also known. Instead of the traditional matching process which contain the unstable RANSAC method to get the affine transformation, this approach is more stable and accurate. Secondly we calculate the stability value of the feature points by the set of image with its affine transformation. Then we get the different feature properties of the feature point, such as DOG features, scales, edge point density, etc. Those two form the training set while stability value is the dependent variable and feature property is the independent variable. At last, a process of training by Rank-SVM is taken. We will get a weight vector. In use, based on the feature properties of each points and weight vector calculated by training, we get the sort value of each feature point which refers to the stability value, then we sort the feature points. In conclusion, we applied our algorithm and the original SIFT detectors to test as a comparison. While in different view changes, blurs, illuminations, it comes as no surprise that experimental results show that our algorithm is more efficient.

  20. NEW METHOD FOR WEAK FAULT FEATURE EXTRACTION BASED ON SECOND GENERATION WAVELET TRANSFORM AND ITS APPLICATION

    Institute of Scientific and Technical Information of China (English)

    Duan Chendong; He Zhengjia; Jiang Hongkai

    2004-01-01

    A new time-domain analysis method that uses second generation wavelet transform (SGWT) for weak fault feature extraction is proposed. To extract incipient fault feature, a biorthogonal wavelet with the characteristics of impact is constructed by using SGWT. Processing detail signal of SGWT with a sliding window devised on the basis of rotating operation cycle, and extracting modulus maximum from each window, fault features in time-domain are highlighted. To make further analysis on the reason of the fault, wavelet package transform based on SGWT is used to process vibration data again. Calculating the energy of each frequency-band, the energy distribution features of the signal are attained. Then taking account of the fault features and the energy distribution, the reason of the fault is worked out. An early impact-rub fault caused by axis misalignment and rotor imbalance is successfully detected by using this method in an oil refinery.

  1. Generating triangulated macromolecular surfaces by Euclidean Distance Transform.

    Directory of Open Access Journals (Sweden)

    Dong Xu

    Full Text Available Macromolecular surfaces are fundamental representations of their three-dimensional geometric shape. Accurate calculation of protein surfaces is of critical importance in the protein structural and functional studies including ligand-protein docking and virtual screening. In contrast to analytical or parametric representation of macromolecular surfaces, triangulated mesh surfaces have been proved to be easy to describe, visualize and manipulate by computer programs. Here, we develop a new algorithm of EDTSurf for generating three major macromolecular surfaces of van der Waals surface, solvent-accessible surface and molecular surface, using the technique of fast Euclidean Distance Transform (EDT. The triangulated surfaces are constructed directly from volumetric solids by a Vertex-Connected Marching Cube algorithm that forms triangles from grid points. Compared to the analytical result, the relative error of the surface calculations by EDTSurf is <2-4% depending on the grid resolution, which is 1.5-4 times lower than the methods in the literature; and yet, the algorithm is faster and costs less computer memory than the comparative methods. The improvements in both accuracy and speed of the macromolecular surface determination should make EDTSurf a useful tool for the detailed study of protein docking and structure predictions. Both source code and the executable program of EDTSurf are freely available at http://zhang.bioinformatics.ku.edu/EDTSurf.

  2. ARTICLES: Some features of parametric conversion of infrared radiation in a system generating a difference frequency

    Science.gov (United States)

    Galaĭchuk, Yu A.; Strizhevskiĭ, V. L.; Yashkir, Yu N.

    1984-11-01

    A fluctuation theory is developed for the parametric conversion of infrared radiation utilizing four-photon difference frequency generation processes. An analysis is made of some features of optical parametric oscillation in this system allowing for sum frequency generation. Parametric "conversion" of quantum fluctuations to the frequency range of the infrared signal is discussed and it is shown that this effect increases the noise level.

  3. Broad features of surface ozone variations over Indian region

    Science.gov (United States)

    Shende, R. R.; Jayaraman, K.; Sreedharan, C. R.; Tiwari, V. S.

    1994-01-01

    Surface ozone concentration at three Indian stations - New Delhi (28.6 deg N), Pune (18.5 deg N) and Thiruvananthapuram (formerly Trivandrum (8.3 deg N) - has been measured since 1973 with the help of an electrochemical continuous ozone recorder. These stations show diurnal, seasonal and annual cycles in surface ozone. Daily changes show that the minimum value occurs at sunrise and maximum in the afternoon. As regards seasonal variations, Thiruvananthapuram and Pune have a minimum value during monsoon season (June to August) while at New Delhi the minimum value occurs in January. However, New Delhi also records low ozone amount during monsoon season identical to the amounts show at Thiruvananthapuram and Pune. The annual cycles at these stations have been compared with similar measurements in the northern and southern hemispheres. The Indian measurements agree well with the annual cycles at these stations. Further, the analysis of the Indian data indicates that the major contribution in surface ozone comes from the natural sources like stratospheric-tropospheric exchange, turbulence, and mixing in the boundary layer; however, a small contribution from anthropogenic sources cannot be ruled out at Pune and probably at New Delhi, especially in winter and summer seasons.

  4. Relativistic surface-plasmon enhanced harmonic generation from gratings

    CERN Document Server

    Fedeli, Luca; Cantono, Giada; Macchi, Andrea

    2016-01-01

    The role of relativistic surface plasmons (SPs) in high order harmonic emission from laser-irradiated grating targets has been investigated by means of particle-in-cell simulations. SP excitation drives a strong enhancement of the intensity of harmonics, particularly in the direction close to the surface tangent. The SP-driven enhancement overlaps with the angular separation of harmonics generated by the grating, which is beneficial for applications requiring monochromatic XUV pulses.

  5. Generating strain signals under consideration of road surface profiles

    Science.gov (United States)

    Putra, T. E.; Abdullah, S.; Schramm, D.; Nuawi, M. Z.; Bruckmann, T.

    2015-08-01

    The current study aimed to develop the mechanism for generating strain signal utilising computer-based simulation. The strain data, caused by the acceleration, were undertaken from a fatigue data acquisition involving car movements. Using a mathematical model, the measured strain signals yielded to acceleration data used to describe the bumpiness of road surfaces. The acceleration signals were considered as an external disturbance on generating strain signals. Based on this comparison, both the actual and simulated strain data have similar pattern. The results are expected to provide new knowledge to generate a strain signal via a simulation.

  6. Engineered biomimicry: polymeric replication of surface features found on insects

    Science.gov (United States)

    Pulsifer, Drew P.; Lakhtakia, Akhlesh; Martín-Palma, Raúl J.; Pantano, Carlo G.

    2011-04-01

    By combining the modified conformal-evaporated-film-by-rotation (M-CEFR) technique with nickel electroforming, we have produced master negatives of nonplanar biotemplates. An approximately 250-nm-thick conformal coating of nanocrystaline nickel is deposited on a surface structure of interest found in class Insecta, and the coating is then reinforced with a roughly 60-μm-thick structural layer of nickel by electroforming. This structural layer endows the M-CEFR coating with the mechanical robustness necessary for casting or stamping multiple polymer replicas of the biotemplate. We have made master negatives of blowfly corneas, beetle elytrons, and butterfly wings.

  7. Studies of surfaces using optical second-harmonic generation

    Energy Technology Data Exchange (ETDEWEB)

    Tom, H.W.K.

    1984-04-01

    The experiments reported in this thesis demonstrate the use of second-harmonic generation (SHG) and sum-frequency generation (SFG) in reflection from surfaces to study various surface properties. The experiments firmly establish SHG as a viable new surface probe that complements existing surface probes in ultrahigh vacuum environments and is in many ways unique for studying interfaces between dense media. Surface structural symmetry can be revealed through the anisotropy in the SH signal from the surface as the sample is rotated about its normal. The form of this anisotropy is derived in theory and verified with an experiment on the Si(100) and (111) surfaces. The SHG and SFG signals from molecules adsorbed on noninteracting substrates have a direct relationship to the number, average orientation, and spectroscopic properties of the molecules. The SH intensity was used to measure the isotherm for adsorption of p-nitrobenzoic acid from ethanolic solution to fused silica. Experiments performed on a strongly-interacting well-characterized Rh(111) surface in ultrahigh vacuum establish the sensitivity of the SH probe in corroboration with other surface probes. For the first time, the SH coverage-dependence was fit by theory in a quantitative way for the case of O-atom adsorption. The sensitivity of SH to adsorption at different sites was established for CO on top- and bridge-sites. SHG was shown to be surface specific in that the SHG from alkali metal surfaces originates from the first two monolayers. SH sensitivity to the adsorption of catalytically-important hydrocarbons and to chemical processes such as benzene dehydrogenation was also demonstrated. 122 references, 27 figures, 2 tables.

  8. A multi-perspective dynamic feature concept in adaptive NC machining of complex freeform surfaces

    OpenAIRE

    Liu, Xu; Li, Yingguang; Gao, James

    2016-01-01

    This paper presents a new concept of feature for freeform surface machining that defines the changes in feature status during real manufacturing situations which have not been sufficiently addressed by current international standards and previous research in feature technology. These changes are multi-perspective, including (i) changes in depth-of-cut: the geometry of a feature in the depth-of-cut direction changes during different machining operations such as roughing, semi-finishing and fin...

  9. An Effective Fault Feature Extraction Method for Gas Turbine Generator System Diagnosis

    Directory of Open Access Journals (Sweden)

    Jian-Hua Zhong

    2016-01-01

    Full Text Available Fault diagnosis is very important to maintain the operation of a gas turbine generator system (GTGS in power plants, where any abnormal situations will interrupt the electricity supply. The fault diagnosis of the GTGS faces the main challenge that the acquired data, vibration or sound signals, contain a great deal of redundant information which extends the fault identification time and degrades the diagnostic accuracy. To improve the diagnostic performance in the GTGS, an effective fault feature extraction framework is proposed to solve the problem of the signal disorder and redundant information in the acquired signal. The proposed framework combines feature extraction with a general machine learning method, support vector machine (SVM, to implement an intelligent fault diagnosis. The feature extraction method adopts wavelet packet transform and time-domain statistical features to extract the features of faults from the vibration signal. To further reduce the redundant information in extracted features, kernel principal component analysis is applied in this study. Experimental results indicate that the proposed feature extracted technique is an effective method to extract the useful features of faults, resulting in improvement of the performance of fault diagnosis for the GTGS.

  10. Design Features and Technology Uncertainties for the Next Generation Nuclear Plant

    Energy Technology Data Exchange (ETDEWEB)

    John M. Ryskamp; Phil Hildebrandt; Osamu Baba; Ron Ballinger; Robert Brodsky; Hans-Wolfgang Chi; Dennis Crutchfield; Herb Estrada; Jeane-Claude Garnier; Gerald Gordon; Richard Hobbins; Dan Keuter; Marilyn Kray; Philippe Martin; Steve Melancon; Christian Simon; Henry Stone; Robert Varrin; Werner von Lensa

    2004-06-01

    This report presents the conclusions, observations, and recommendations of the Independent Technology Review Group (ITRG) regarding design features and important technology uncertainties associated with very-high-temperature nuclear system concepts for the Next Generation Nuclear Plant (NGNP). The ITRG performed its reviews during the period November 2003 through April 2004.

  11. Speeding Up the 3D Surface Generator VESTA

    CERN Document Server

    Schlei, B R

    2010-01-01

    The very recent volume-enclosing surface extraction algorithm, VESTA, is revisited. VESTA is used to determine implicit surfaces that are potentially contained in 3D data sets, such as 3D image data and/or 3D simulation data. VESTA surfaces are non-degenerate, i.e., they always enclose a volume that is larger than zero and they never self-intersect, prior to a further processing, e.g., towards isosurfaces. In addition to its ability to deal with local cell ambiguities consistently - and thereby avoiding the accidental generation of holes in the final surfaces - the information of the interior and/or exterior of enclosed 3D volumes is propagated correctly to each of the final surface tiles. Particular emphasis is put here on the speed up of the original formulation of VESTA, while applying the algorithm to 2x2x2 voxel neighborhoods.

  12. All-optical generation of surface plasmons in graphene

    Science.gov (United States)

    Constant, T. J.; Hornett, S. M.; Chang, D. E.; Hendry, E.

    2016-02-01

    Surface plasmons in graphene offer a compelling route to many useful photonic technologies. As a plasmonic material, graphene offers several intriguing properties, such as excellent electro-optic tunability, crystalline stability, large optical nonlinearities and extremely high electromagnetic field concentration. As such, recent demonstrations of surface plasmon excitation in graphene using near-field scattering of infrared light have received intense interest. Here we present an all-optical plasmon coupling scheme which takes advantage of the intrinsic nonlinear optical response of graphene. Free-space, visible light pulses are used to generate surface plasmons in a planar graphene sheet using difference frequency wave mixing to match both the wavevector and energy of the surface wave. By carefully controlling the phase matching conditions, we show that one can excite surface plasmons with a defined wavevector and direction across a large frequency range, with an estimated photon efficiency in our experiments approaching 10-5.

  13. Interpretation of nonlinearity in wind generated ocean surface waves

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J.

    This study attempts to resolve a mix-up between a physical process and its mathematical interpretation in the context of wind waves on ocean surface. Wind generated wave systems, are conventionally interpreted as a result of interaction of a number...

  14. Features of Ion-Electronic Emission from Surface of Semiconductors

    Directory of Open Access Journals (Sweden)

    A. Kurochka

    2013-12-01

    Full Text Available The results of the research value of the current of the secondary electrons in the ion-beam etching of various semiconductors. Shows the setup and electrical circuit of the experiment. An experimental study to determine the dependence of the current of the secondary electrons from the band gap Eg and the height of the potential barrier (electron affinity eχ. It is shown that in the conditions of ion-beam etching of the semiconductor is the penetration of the electric field, which leads to a shift of the energy levels of electrons in the surface layer. Found that the ion-electronic signal emission silicon n-type is higher than the p-type silicon.

  15. Surface characters of internal waves generated by Rankine ovoid

    Institute of Scientific and Technical Information of China (English)

    Zhaoting Xu; Xu Chen; Izolda V. Sturova

    2006-01-01

    A linear theory on the internal waves generated in the stratified fluid with a pycnocline is presented in this paper. The internal wave fields such as the velocity fields in the stratified fluid and velocity gradient fields at the free surface are also investigated by means of the theoretical and numerical method. From the numerical results, it is shown that the internal wave generated by horizontally moving Rankine ovoid is a sort of trapped wave which propagates in a wave guide, and its waveform is a kind of Mach front-type internal wave in the pycnocline. Influence of the internal wave on the flow fields at the free surface is represented by the velocity gradient fields resulted from the internal waves generated by motion of the Rankine ovoid. At the same time, it is also shown that under the hypothesis of inviscid fluid, the synchronism between the surface velocity gradient fields at the free surface and the internal wave fields in the fluid is retained. This theory opens a possibility to study further the modulated spectrum of the Bragg waves at the free surface.

  16. Local-Scale Simulations of Nucleate Boiling on Micrometer Featured Surfaces: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Sitaraman, Hariswaran [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Moreno, Gilberto [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Narumanchi, Sreekant V [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-08-03

    A high-fidelity computational fluid dynamics (CFD)-based model for bubble nucleation of the refrigerant HFE7100 on micrometer-featured surfaces is presented in this work. The single-fluid incompressible Navier-Stokes equations, along with energy transport and natural convection effects are solved on a featured surface resolved grid. An a priori cavity detection method is employed to convert raw profilometer data of a surface into well-defined cavities. The cavity information and surface morphology are represented in the CFD model by geometric mesh deformations. Surface morphology is observed to initiate buoyancy-driven convection in the liquid phase, which in turn results in faster nucleation of cavities. Simulations pertaining to a generic rough surface show a trend where smaller size cavities nucleate with higher wall superheat. This local-scale model will serve as a self-consistent connection to larger device scale continuum models where local feature representation is not possible.

  17. Chemical modifications of silicon surfaces for the generation of a tunable surface isoelectric point

    NARCIS (Netherlands)

    van der Maaden, Koen; Tomar, Jasmine; Jiskoot, Wim; Bouwstra, Joke

    2014-01-01

    The aim of this work was to generate a tunable surface isoelectric point (sIEP), where the surface is modified with two molecules: a weak base (pyridine), carrying a pH dependent positive charge, and a derivative of a strong acid (sulfate), carrying a permanent negative charge in a physiologically r

  18. A Feature-adaptive Subdivision Method for Real-time 3D Reconstruction of Repeated Topology Surfaces

    Science.gov (United States)

    Lin, Jinhua; Wang, Yanjie; Sun, Honghai

    2017-03-01

    It's well known that rendering for a large number of triangles with GPU hardware tessellation has made great progress. However, due to the fixed nature of GPU pipeline, many off-line methods that perform well can not meet the on-line requirements. In this paper, an optimized Feature-adaptive subdivision method is proposed, which is more suitable for reconstructing surfaces with repeated cusps or creases. An Octree primitive is established in irregular regions where there are the same sharp vertices or creases, this method can find the neighbor geometry information quickly. Because of having the same topology structure between Octree primitive and feature region, the Octree feature points can match the arbitrary vertices in feature region more precisely. In the meanwhile, the patches is re-encoded in the Octree primitive by using the breadth-first strategy, resulting in a meta-table which allows for real-time reconstruction by GPU hardware tessellation unit. There is only one feature region needed to be calculated under Octree primitive, other regions with the same repeated feature generate their own meta-table directly, the reconstruction time is saved greatly for this step. With regard to the meshes having a large number of repeated topology feature, our algorithm improves the subdivision time by 17.575% and increases the average frame drawing time by 0.2373 ms compared to the traditional FAS (Feature-adaptive Subdivision), at the same time the model can be reconstructed in a watertight manner.

  19. Vortices generation in the reactive flow on the evaporative surface

    Energy Technology Data Exchange (ETDEWEB)

    Park, Cha Ryeom; Lee, Chang Jin [Konkuk University, Seoul (Korea, Republic of)

    2015-02-15

    Vortices generation and flow dynamics are investigated by a numerical calculation with LES methodology on the evaporative surface including chemical reactions. For simplicity, fuel is radially injected from the surface in order to decouple pyrolysis of solid fuel from the governing equation and consideration of heat transfer balance. Nevertheless its simple treatment of chemical reactions and fuel pyrolysis, numerical results captured very fundamental understandings in terms of averaged temperature, velocity profile, and mixture fraction distribution. Results showed that a well-defined turbulent velocity profile at the inlet becomes twisted and highly wrinkled in the downstream reaching the maximum velocity at far above the surface, where the flame is located. And the thickness of boundary layer increases in the downstream due to the enhanced interaction of axial flow and mass injection from the surface. Also, chemical reaction appears highly active and partially concentrated along the plane where flow condition is in stoichiometric. In particular, flame front locates at the surface where mixture fraction Z equals to 0.07. Flame front severely wrinkles in the downstream by the interaction with turbulences in the flow. Partial reactions on the flame front contribute to produce hot spots periodically in the downstream attaining the max temperature at the center of each spot. This may take the role of additional unsteady heat generations and pressure perturbations in the downstream. Future study will focus on the evolution of hot spots and pressure perturbations in the post chamber of lab scale hybrid rocket motors.

  20. Advanced Automatic Hexahedral Mesh Generation from Surface Quad Meshes

    OpenAIRE

    Kremer, Michael; Bommes, David; Lim, Isaak; Kobbelt, Leif

    2013-01-01

    International audience; A purely topological approach for the generation of hexahedral meshes from quadrilateral surface meshes of genus zero has been proposed by M. Müller-Hannemann: in a first stage, the input surface mesh is reduced to a single hexahedron by successively eliminating loops from the dual graph of the quad mesh; in the second stage, the hexahedral mesh is constructed by extruding a layer of hexahedra for each dual loop from the first stage in reverse elimination order. In th...

  1. Second harmonic generation spectroscopy on Si surfaces and interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Pedersen, Kjeld [Department of Physics and Nanotechnology, Aalborg University, Skjernvej 4A, 9220 Aalborg Oest (Denmark)

    2010-08-15

    Optical second harmonic generation (SHG) spectroscopy studies of Si(111) surfaces and interfaces are reviewed for two types of systems: (1) clean 7 x 7 and {radical}(3) x {radical}(3)-Ag reconstructed surfaces prepared under ultra-high vacuum conditions where surface states are excited and (2) interfaces in silicon-on-insulator (SOI) structures and thin metal films on Si surfaces where several interfaces contribute to the SHG. In all the systems resonances are seen at interband transitions near the bulk critical points E{sub 1} and E{sub 2}. On the clean surfaces a number of resonances appear below the onset of bulk-like interband transitions that can be referred to excitations of dangling bond surface states. Adsorption of oxygen leads to formation of a new surface resonance. Such resonances appearing in the region between the bulk critical points E{sub 1} and E{sub 2} are also shown to be important for Si/oxide interfaces in SOI structures. Finally, examples of spectroscopy on layers buried below thin Ag and Au films are given. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  2. Surface features on Sahara soil dust particles made visible by atomic force microscope (AFM) phase images

    Science.gov (United States)

    Helas, G.; Andreae, M. O.

    2008-10-01

    We show that atomic force microscopy (AFM) phase images can reveal surface features of soil dust particles, which are not evident using other microscopic methods. The non-contact AFM method is able to resolve topographical structures in the nanometer range as well as to uncover repulsive atomic forces and attractive van der Waals' forces, and thus gives insight to surface properties. Though the method does not allow quantitative assignment in terms of chemical compound description, it clearly shows deposits of distinguishable material on the surface. We apply this technique to dust aerosol particles from the Sahara collected over the Atlantic Ocean and describe micro-features on the surfaces of such particles.

  3. Surface plasmon polariton-induced hot carrier generation for photocatalysis.

    Science.gov (United States)

    Ahn, Wonmi; Ratchford, Daniel C; Pehrsson, Pehr E; Simpkins, Blake S

    2017-03-02

    Non-radiative plasmon decay in noble metals generates highly energetic carriers under visible light irradiation, which opens new prospects in the fields of photocatalysis, photovoltaics, and photodetection. While localized surface plasmon-induced hot carrier generation occurs in diverse metal nanostructures, inhomogeneities typical of many metal-semiconductor plasmonic nanostructures hinder predictable control of photocarrier generation and therefore reproducible carrier-mediated photochemistry. Here, we generate traveling surface plasmon polaritons (SPPs) at the interface between a noble metal/titanium dioxide (TiO2) heterostructure film and aqueous solution, enabling simultaneous optical and electrochemical interrogation of plasmon-mediated chemistry in a system whose resonance may be continuously tuned via the incident optical excitation angle. To the best of our knowledge, this is the first experimental demonstration of SPP-induced hot carrier generation for photocatalysis. We found electrochemical photovoltage and photocurrent responses as SPP-induced hot carriers drive both solution-based oxidation of methanol and the anodic half-reaction of photoelectrochemical water-splitting in sodium hydroxide solution. A strong excitation angle dependence and linear power dependence in the electrochemical photocurrent confirm that the photoelectrochemical reactions are SPP-driven. SPP-generated hot carrier chemistry was recorded on gold and silver and with two different excitation wavelengths, demonstrating potential for mapping resonant charge transfer processes with this technique. These results will provide the design criteria for a metal-semiconductor hybrid system with enhanced hot carrier generation and transport, which is important for the understanding and application of plasmon-induced photocatalysis.

  4. A new procedure for characterizing textured surfaces with a deterministic pattern of valley features

    DEFF Research Database (Denmark)

    Godi, Alessandro; Kühle, A; De Chiffre, Leonardo

    2013-01-01

    In recent years there has been the development of a high number of manufacturing methods for creating textured surfaces which often present deterministic patterns of valley features. Unfortunately, suitable methodologies for characterizing them are lacking. Existing standards cannot in fact...

  5. Nonlinear mixing of laser generated narrowband Rayleigh surface waves

    Science.gov (United States)

    Bakre, Chaitanya; Rajagopal, Prabhu; Balasubramaniam, Krishnan

    2017-02-01

    This research presents the nonlinear mixing technique of two co-directionally travelling Rayleigh surface waves generated and detected using laser ultrasonics. The optical generation of Rayleigh waves on the specimen is obtained by shadow mask method. In conventional nonlinear measurements, the inherently small higher harmonics are greatly influenced by the nonlinearities caused by coupling variabilities and surface roughness between the transducer and specimen interface. The proposed technique is completely contactless and it should be possible to eliminate this problem. Moreover, the nonlinear mixing phenomenon yields not only the second harmonics, but also the sum and difference frequency components, which can be used to measure the acoustic nonlinearity of the specimen. In this paper, we will be addressing the experimental configurations for this technique. The proposed technique is validated experimentally on Aluminum 7075 alloy specimen.

  6. Comparative evaluation of surface and downhole steam-generation techniques

    Science.gov (United States)

    Hart, C.

    The application of heat to reservoirs containing high API gravity oils can substantially improve recovery. Although steam injection is currently the principal thermal recovery method, heat transmission losses associated with delivery of the steam from the surface generators to the oil bearing formation has limited conventional steam injection to shallow reservoirs. The objective of the Department of Energy's Project DEEP STEAM is to develop the technology required to economically produce heavy oil from deep reservoirs. The tasks included in this effort are the development and evaluation of thermally efficient delivery systems and downhole steam generation systems. The technical and economic performance of conventional surface steam drives, which are strongly influenced by heat losses are compared. The selection of a preferred technology based upon either total efficiency or cost is found to be strongly influenced by reservoir depth, steam mass flow rate, and sandface steam quality.

  7. Electrochemically Smart Bimetallic Materials Featuring Group 11 Metals: In-situ Conductive Network Generation and Its Impact on Cell Capacity

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, Esther [Stony Brook Univ., NY (United States)

    2016-11-30

    Our results for this program “Electrochemically smart bimetallic materials featuring Group 11 metals: in-situ conductive matrix generation and its impact on battery capacity, power and reversibility” have been highly successful: 1) we demonstrated material structures which generated in-situ conductive networks through electrochemical activation with increases in conductivity up to 10,000 fold, 2) we pioneered in situ analytical methodology to map the cathodes at several stages of discharge through the use of Energy Dispersive X-ray Diffraction (EDXRD) to elucidate the kinetic dependence of the conductive network formation, and 3) we successfully designed synthetic methodology for direct control of material properties including crystallite size and surface area which showed significant impact on electrochemical behavior.

  8. A Tool Path Generation Strategy for Sculptured Surfaces Machining

    Institute of Scientific and Technical Information of China (English)

    Chen Tao; Zhong Yifang; Zhou Ji

    2001-01-01

    This paper presents a strategy to generate interference-free tool paths for machiningsculptured surfaces. The strategy proposed here is first to determine the tool path topology. Thevalues of the step length and the path interval are then calculated based on the machining tolerancerequirements. After detecting and eliminating the tool interference, the interference-free tool path isgenerated. The effectiveness of the developed algorithm is demonstrated through simulation andactual cutting tests.

  9. THE NEXT GENERATION VIRGO CLUSTER SURVEY. XIV. Shell feature early-type dwarf galaxies in the Virgo cluster

    CERN Document Server

    Paudel, Sanjaya; Duc, Pierre-Alain; Côté, Patrick; Cuillandre, Jean-Charles; Ferrarese, Laura; Blakeslee, John P; Boselli, Alessandro; Cantiello, Michele; Gwyn, S D J; Guhathakurta, Puragra; Mei, Simona; Mihos, J Christopher; Peng, Eric W; Powalka, Mathieu; Sánchez-Janssen, Rúben; Toloba, Elisa; Zhang, Hongxin

    2016-01-01

    The Next Generation Virgo Cluster Survey is a deep (with a $2\\sigma$ detection limit $\\mu_g$ = 29~mag~arcsec$^{-2}$ in the $g-$band) optical panchromatic survey targeting the Virgo cluster from its core to virial radius, for a total areal coverage of 104 square degrees. As such, the survey is well suited for the study of galaxies' outskirts, haloes and low surface brightness features that arise from dynamical interactions within the cluster environment. We report the discovery of extremely faint ($\\mu_g$ $>$ 25 mag arcsec$^{-2}$) shells in three Virgo cluster early-type dwarf galaxies, VCC~1361, VCC~1447 and VCC~1668. Among them, VCC~1447 has an absolute magnitude M$_{g}$ = -11.71 mag and is {\\it the least massive galaxy with a shell system discovered to date}. We present a detailed study of these low surface brightness features. We detect between three and four shells in each of our galaxies. Within the uncertainties, we find no evidence of a color difference between the galaxy main body and shell features. ...

  10. On the generation of internal wave modes by surface waves

    Science.gov (United States)

    Harlander, Uwe; Kirschner, Ian; Maas, Christian; Zaussinger, Florian

    2016-04-01

    Internal gravity waves play an important role in the ocean since they transport energy and momentum and the can lead to mixing when they break. Surface waves and internal gravity waves can interact. On the one hand, long internal waves imply a slow varying shear current that modifies the propagation of surface waves. Surface waves generated by the atmosphere can, on the other hand, excite internal waves by nonlinear interaction. Thereby a surface wave packet consisting of two close frequencies can resonate with a low frequency internal wave (Phillips, 1966). From a theoretical point of view, the latter has been studied intensively by using a 2-layer model, i.e. a surface layer with a strong density contrast and an internal layer with a comparable weak density contrast (Ball, 1964; Craig et al., 2010). In the present work we analyse the wave coupling for a continuously stratified fluid using a fully non-linear 2D numerical model (OpenFoam) and compare this with laboratory experiments (see Lewis et al. 1974). Surface wave modes are used as initial condition and the time development of the dominant surface and internal waves are studied by spectral and harmonic analysis. For the simple geometry of a box, the results are compared with analytical spectra of surface and gravity waves. Ball, F.K. 1964: Energy transfer between external and internal gravity waves. J. Fluid Mech. 19, 465. Craig, W., Guyenne, P., Sulem, C. 2010: Coupling between internal and surface waves. Natural Hazards 57, 617-642. Lewis, J.E., Lake, B.M., Ko, D.R.S 1974: On the interaction of internal waves and surfacr gravity waves, J. Fluid Mech. 63, 773-800. Phillips, O.M. 1966: The dynamics of the upper ocean, Cambridge University Press, 336pp.

  11. Structuring feature space: a non-parametric method for volumetric transfer function generation.

    Science.gov (United States)

    Maciejewski, Ross; Woo, Insoo; Chen, Wei; Ebert, David S

    2009-01-01

    The use of multi-dimensional transfer functions for direct volume rendering has been shown to be an effective means of extracting materials and their boundaries for both scalar and multivariate data. The most common multi-dimensional transfer function consists of a two-dimensional (2D) histogram with axes representing a subset of the feature space (e.g., value vs. value gradient magnitude), with each entry in the 2D histogram being the number of voxels at a given feature space pair. Users then assign color and opacity to the voxel distributions within the given feature space through the use of interactive widgets (e.g., box, circular, triangular selection). Unfortunately, such tools lead users through a trial-and-error approach as they assess which data values within the feature space map to a given area of interest within the volumetric space. In this work, we propose the addition of non-parametric clustering within the transfer function feature space in order to extract patterns and guide transfer function generation. We apply a non-parametric kernel density estimation to group voxels of similar features within the 2D histogram. These groups are then binned and colored based on their estimated density, and the user may interactively grow and shrink the binned regions to explore feature boundaries and extract regions of interest. We also extend this scheme to temporal volumetric data in which time steps of 2D histograms are composited into a histogram volume. A three-dimensional (3D) density estimation is then applied, and users can explore regions within the feature space across time without adjusting the transfer function at each time step. Our work enables users to effectively explore the structures found within a feature space of the volume and provide a context in which the user can understand how these structures relate to their volumetric data. We provide tools for enhanced exploration and manipulation of the transfer function, and we show that the initial

  12. Automatic Tool Path Generation for Robot Integrated Surface Sculpturing System

    Science.gov (United States)

    Zhu, Jiang; Suzuki, Ryo; Tanaka, Tomohisa; Saito, Yoshio

    In this paper, a surface sculpturing system based on 8-axis robot is proposed, the CAD/CAM software and tool path generation algorithm for this sculpturing system are presented. The 8-axis robot is composed of a 6-axis manipulator and a 2-axis worktable, it carves block of polystyrene foams by heated cutting tools. Multi-DOF (Degree of Freedom) robot benefits from the faster fashion than traditional RP (Rapid Prototyping) methods and more flexibility than CNC machining. With its flexibility driven from an 8-axis configuration, as well as efficient custom-developed software for rough cutting and finish cutting, this surface sculpturing system can carve sculptured surface accurately and efficiently.

  13. Surface Defect Target Identification on Copper Strip Based on Adaptive Genetic Algorithm and Feature Saliency

    Directory of Open Access Journals (Sweden)

    Xuewu Zhang

    2013-01-01

    Full Text Available To enhance the stability and robustness of visual inspection system (VIS, a new surface defect target identification method for copper strip based on adaptive genetic algorithm (AGA and feature saliency is proposed. First, the study uses gray level cooccurrence matrix (GLCM and HU invariant moments for feature extraction. Then, adaptive genetic algorithm, which is used for feature selection, is evaluated and discussed. In AGA, total error rates and false alarm rates are integrated to calculate the fitness value, and the probability of crossover and mutation is adjusted dynamically according to the fitness value. At last, the selected features are optimized in accordance with feature saliency and are inputted into a support vector machine (SVM. Furthermore, for comparison, we conduct experiments using the selected optimal feature subsequence (OFS and the total feature sequence (TFS separately. The experimental results demonstrate that the proposed method can guarantee the correct rates of classification and can lower the false alarm rates.

  14. Secure Biometric Key Generation Scheme for Cryptography using Combined Biometric Features of Fingerprint and Iris

    Directory of Open Access Journals (Sweden)

    Mr.P.Balakumar

    2011-09-01

    Full Text Available Exact and automatic recognition and authentication of users are a essential difficulty in all systems. Shared secrets like Personal Identification Numbers or Passwords and key devices such as Smart cards are not presently sufficient in few situations. What is required is a system that could authenticate that the person is actually the person. The biometrics is improving the capability to recognize the persons. The usage of biometrics system permits the recognition of a living person according to the physiological features or behavioral features to be recognized without human involvement. This leads to the world wide usage of biometrics to secure the system. The various biometrics used in securing system are fingerprint, iris, retina, etc. The construction of cryptographic key from biometrics is used generally to secure the system. The efficiency and the flexibility of the cryptographic make it suitable for securing purpose. In some times, biometrics can be stolen; this makes the attackers to access the system for any time. This problem is diminished in this paper by using two biometrics features. The biometrics used in this paper is fingerprint and iris. These two features are combined with the help of fusion algorithm. From the combined features, cryptographic key is generated. The experimental result shows that the proposed techniques results in better security than the existing techniques.

  15. Optimization of mask manufacturing rule check constraint for model based assist feature generation

    Science.gov (United States)

    Shim, Seongbo; Kim, Young-chang; Chun, Yong-jin; Lee, Seong-Woo; Lee, Suk-joo; Choi, Seong-woon; Han, Woo-sung; Chang, Seong-hoon; Yoon, Seok-chan; Kim, Hee-bom; Ki, Won-tai; Woo, Sang-gyun; Cho, Han-gu

    2008-11-01

    SRAF (sub-resolution assist feature) generation technology has been a popular resolution enhancement technique in photo-lithography past sub-65nm node. It helps to increase the process window, and these are some times called ILT(inverse lithography technology). Also, many studies have been presented on how to determine the best positions of SRAFs, and optimize its size. According to these reports, the generation of SRAF can be formulated as a constrained optimization problem. The constraints are the side lobe suppression and allowable minimum feature size or MRC (mask manufacturing rule check). As we know, bigger SRAF gives better contribution to main feature but susceptible to SRAF side lobe issue. Thus, we finally have no choice but to trade-off the advantages of the ideally optimized mask that contains very complicated SRAF patterns to the layout that has been MRC imposed applied to it. The above dilemma can be resolved by simultaneously using lower dose (high threshold) and cleaning up by smaller MRC. This solution makes the room between threshold (side lobe limitation) and MRC constraint (minimum feature limitation) wider. In order to use smaller MRC restriction without considering the mask writing and inspection issue, it is also appropriate to identify the exact mask writing limitation and find the smart mask constraints that well reflect the mask manufacturability and the e-beam lithography characteristics. In this article, we discuss two main topics on mask optimizations with SRAF. The first topic is on the experimental work to find what behavior of the mask writing ability is in term of several MRC parameters, and we propose more effective MRC constraint for aggressive generation of SRAF. The next topic is on finding the optimum MRC condition in practical case, 3X nm node DRAM contact layer. In fact, it is not easy to encompass the mask writing capability for very complicate real SRAF pattern by using the current MRC constraint based on the only width and

  16. Features of wind field over the sea surface in the coastal area

    Science.gov (United States)

    Monzikova, A. K.; Kudryavtsev, V. N.; Myasoedov, A. G.; Chapron, B.; Zilitinkevich, S. S.

    2017-01-01

    In this paper we analyze SAR wind field features, in particular the effects of wind shadowing. These effects represent the dynamics of the internal atmospheric boundary layer, which is formed due to the transition of the air flow arriving from the rough land surface to the "smooth" water surface. In the wind-shadowed area, the flow accelerates, and a surface wind stress increases with fetch. The width of the shadow depends not only on the wind speed and atmospheric boundary layer stratification, but also on geographic features such as windflow multiple transformations over the complex surface land-Lake Chudskoe-land-Gulf of Finland. Measurements showed that, in the area of wind acceleration, the surface stress normalized by an equilibrium value (far from the coast) is a universal function of dimensionless fetch Xf/G. Surface wind stress reaches an equilibrium value at Xf/G ≈ 0.4, which is the scale of the planetary-boundary-layer relaxation.

  17. LEDs on HVPE grown GaN substrates: Influence of macroscopic surface features

    Directory of Open Access Journals (Sweden)

    SK. S. Rahman

    2014-07-01

    Full Text Available We demonstrate the strong influence of GaN substrate surface morphology on optical properties and performance of light emitting devices grown on freestanding GaN. As-grown freestanding HVPE GaN substrates show excellent AFM RMS and XRD FWHM values over the whole area, but distinctive features were observed on the surface, such as macro-pits, hillocks and facets extending over several millimeters. Electroluminescence measurements reveal a strong correlation of the performance and peak emission wavelength of LEDs with each of these observed surface features. This results in multiple peaks and non-uniform optical output power for LEDs on as-grown freestanding GaN substrates. Removal of these surface features by chemical mechanical polishing results in highly uniform peak wavelength and improved output power over the whole wafer area.

  18. Multifunctional Indium Tin Oxide Electrode Generated by Unusual Surface Modification

    Science.gov (United States)

    Bouden, Sarra; Dahi, Antoine; Hauquier, Fanny; Randriamahazaka, Hyacinthe; Ghilane, Jalal

    2016-11-01

    The indium tin oxide (ITO) material has been widely used in various scientific fields and has been successfully implemented in several devices. Herein, the electrochemical reduction of ITO electrode in an organic electrolytic solution containing alkali metal, NaI, or redox molecule, N-(ferrocenylmethyl) imidazolium iodide, was investigated. The reduced ITO surfaces were investigated by X-ray photoelectron spectroscopy and grazing incident XRD demonstrating the presence of the electrolyte cation inside the material. Reversibility of this process after re-oxidation was evidenced by XPS. Using a redox molecule based ionic liquid as supporting electrolyte leads to fellow electrochemically the intercalation process. As a result, modified ITO containing ferrocenyl imidazolium was easily generated. This reduction process occurs at mild reducing potential around -1.8 V and causes for higher reducing potential a drastic morphological change accompanied with a decrease of the electrode conductivity at the macroscopic scale. Finally, the self-reducing power of the reduced ITO phase was used to initiate the spontaneous reduction of silver ions leading to the growth of Ag nanoparticles. As a result, transparent and multifunctional active ITO surfaces were generated bearing redox active molecules inside the material and Ag nanoparticles onto the surface.

  19. Computer Graphics Meets Image Fusion: the Power of Texture Baking to Simultaneously Visualise 3d Surface Features and Colour

    Science.gov (United States)

    Verhoeven, G. J.

    2017-08-01

    Since a few years, structure-from-motion and multi-view stereo pipelines have become omnipresent in the cultural heritage domain. The fact that such Image-Based Modelling (IBM) approaches are capable of providing a photo-realistic texture along the threedimensional (3D) digital surface geometry is often considered a unique selling point, certainly for those cases that aim for a visually pleasing result. However, this texture can very often also obscure the underlying geometrical details of the surface, making it very hard to assess the morphological features of the digitised artefact or scene. Instead of constantly switching between the textured and untextured version of the 3D surface model, this paper presents a new method to generate a morphology-enhanced colour texture for the 3D polymesh. The presented approach tries to overcome this switching between objects visualisations by fusing the original colour texture data with a specific depiction of the surface normals. Whether applied to the original 3D surface model or a lowresolution derivative, this newly generated texture does not solely convey the colours in a proper way but also enhances the smalland large-scale spatial and morphological features that are hard or impossible to perceive in the original textured model. In addition, the technique is very useful for low-end 3D viewers, since no additional memory and computing capacity are needed to convey relief details properly. Apart from simple visualisation purposes, the textured 3D models are now also better suited for on-surface interpretative mapping and the generation of line drawings.

  20. Investigations of micron and submicron wear features of diseased human cartilage surfaces.

    Science.gov (United States)

    Peng, Zhongxiao; Baena, Juan C; Wang, Meiling

    2015-02-01

    Osteoarthritis is a common disease. However, its causes and morphological features of diseased cartilage surfaces are not well understood. The purposes of this research were (a) to develop quantitative surface characterization techniques to study human cartilages at a micron and submicron scale and (b) to investigate distinctive changes in the surface morphologies and biomechanical properties of the cartilages in different osteoarthritis grades. Diseased cartilage samples collected from osteoarthritis patients were prepared for image acquisition using two different techniques, that is, laser scanning microscopy at a micrometer scale and atomic force microscopy at a nanometer scale. Three-dimensional, digital images of human cartilages were processed and analyzed quantitatively. This study has demonstrated that high-quality three-dimensional images of human cartilage surfaces could be obtained in a hydrated condition using laser scanning microscopy and atomic force microscopy. Based on the numerical data extracted from improved image quality and quantity, it has been found that osteoarthritis evolution can be identified by specific surface features at the micrometer scale, and these features are amplitude and functional property related. At the submicron level, the spatial features of the surfaces were revealed to differ between early and advanced osteoarthritis grades. The effective indentation moduli of human cartilages effectively revealed the cartilage deterioration. The imaging acquisition and numerical analysis methods established allow quantitative studies of distinctive changes in cartilage surface characteristics and better understanding of the cartilage degradation process.

  1. Nanoparticle generation and interactions with surfaces in vacuum systems

    Science.gov (United States)

    Khopkar, Yashdeep

    Extreme ultraviolet lithography (EUVL) is the most likely candidate as the next generation technology beyond immersion lithography to be used in high volume manufacturing in the semiconductor industry. One of the most problematic areas in the development process is the fabrication of mask blanks used in EUVL. As the masks are reflective, there is a chance that any surface aberrations in the form of bumps or pits could be printed on the silicon wafers. There is a strict tolerance to the number density of such defects on the mask that can be used in the final printing process. Bumps on the surface could be formed when particles land on the mask blank surface during the deposition of multiple bi-layers of molybdenum and silicon. To identify, and possibly mitigate the source of particles during mask fabrication, SEMATECH investigated particle generation in the VEECO Nexus deposition tool. They found several sources of particles inside the tool such as valves. To quantify the particle generation from vacuum components, a test bench suitable for evaluating particle generation in the sub-100 nm particle size range was needed. The Nanoparticle test bench at SUNY Polytechnic Institute was developed as a sub-set of the overall SEMATECH suite of metrology tools used to identify and quantify sources of particles inside process tools that utilize these components in the semiconductor industry. Vacuum valves were tested using the test bench to investigate the number, size and possible sources of particles inside the valves. Ideal parameters of valve operation were also investigated using a 300-mm slit valve with the end goal of finding optimized parameters for minimum particle generation. SEMATECH also pursued the development of theoretical models of particle transport replicating the expected conditions in an ion beam deposition chamber assuming that the particles were generated. In the case of the ion beam deposition tool used in the mask blank fabrication process, the ion

  2. Obtaining 3d models of surface snow and ice features (penitentes) with a Xbox Kinect

    Science.gov (United States)

    Nicholson, Lindsey; Partan, Benjamin; Pętlicki, Michał; MacDonell, Shelley

    2014-05-01

    Penitentes are snow or ice spikes that can reach several metres in height. They are a common feature of snow and ice surfaces in the semi-arid Andes as their formation is favoured by very low humidity, persistently low temperatures and sustained high solar radiation. While the conditions of their formation are relatively well constrained it is not yet clear how their presence influences the rate of mass loss and meltwater production from the mountain cryosphere and there is a need for accurate measurements of ablation within penitente fields through time in order to evaluate how well existing energy balance models perform for surfaces with penitentes. The complex surface morphology poses a challenge to measuring the mass loss at snow or glacier surfaces as (i) the spatial distribution of surface lowering within a penitente field is very heterogeneous, and (ii) the steep walls and sharp edges of the penitentes limit the line of sight view for surveying from fixed positions. In this work we explored whether these problems can be solved by using the Xbox Kinect sensor to generate small scale digital terrain models (DTMs) of sample areas of snow and ice penitentes. The study site was Glaciar Tapado in Chile (30°08'S; 69°55'W) where three sample sites were monitored from November 2013 to January 2014. The range of the Kinect sensor was found to be restricted to about 1 m over snow and ice, and scanning was only possible after dusk. Moving the sensor around the penitente field was challenging and often resulted in fragmented scans. However, despite these challenges, the scans obtained could be successfully combined in MeshLab software to produce good surface representations of the penitentes. GPS locations of target stakes in the sample plots allow the DTMs to be orientated correctly in space so the morphology of the penitente field and the volume loss through time can be fully described. At the study site in snow penitentes the Kinect DTM was compared with the quality

  3. Highly efficient singular surface plasmon generation by achiral apertures

    CERN Document Server

    Jiang, Quanbo; Bellessa, Joel; Huant, Serge; Genet, Cyriaque; Drezet, Aurélien

    2016-01-01

    We report a highly efficient generation of singular surface plasmon (SP) field by an achiral plasmonic structure consisting of $\\Lambda$-shaped apertures. Our quantitative analysis based on leakage radiation microscopy (LRM) demonstrates that the induced spin-orbit coupling can be tuned by adjusting the apex angle of the $\\Lambda$-shaped aperture. Specifically, the array of $\\Lambda$-shaped apertures with the apex angle $60^\\circ$ is shown to give rise to the directional coupling efficiency. The ring of $\\Lambda$-shaped apertures with the apex angle $60^\\circ$ realized to generate the maximum extinction ratio (ER=11) for the SP singularities between two different polarization states. This result provides a more efficient way for developing SP focusing and SP vortex in the field of nanophotonics such as optical tweezers.

  4. CargoCBM - Feature Generation and Classification for a Condition Monitoring System for Freight Wagons

    Science.gov (United States)

    Gericke, C.; Hecht, M.

    2012-05-01

    Despite the fact that rail freight transport is one of the most environmentally friendly matters of transport, its growth has been far behind the growth of freight transport in general. Studies showed that a competitive disadvantage is caused by a low availability of rolling stock, especially freight wagons. Changing from a time based to a condition based maintenance strategy is believed to decrease down times by at least one third. To make condition based maintenance for freight wagons possible the TU Berlin and five industry partners started the research project CargoCBM. One task in this project is to develop algorithms for the automatic on-board diagnosis of wheel flats. The focus of the work is on the process of feature generation and feature selection as well as the application of different classifiers to automatically evaluate the data. Based on the results of measured data, features were selected and tested with different classifiers. Thought advanced classifiers such as neural networks have been analysed in accordance to their classification accuracy. It can be shown that with carefully constructed and selected features comparatively simple classifiers can lead to excellent results.

  5. Sensitivity analysis of surface runoff generation in urban flood forecasting.

    Science.gov (United States)

    Simões, N E; Leitão, J P; Maksimović, C; Sá Marques, A; Pina, R

    2010-01-01

    Reliable flood forecasting requires hydraulic models capable to estimate pluvial flooding fast enough in order to enable successful operational responses. Increased computational speed can be achieved by using a 1D/1D model, since 2D models are too computationally demanding. Further changes can be made by simplifying 1D network models, removing and by changing some secondary elements. The Urban Water Research Group (UWRG) of Imperial College London developed a tool that automatically analyses, quantifies and generates 1D overland flow network. The overland flow network features (ponds and flow pathways) generated by this methodology are dependent on the number of sewer network manholes and sewer inlets, as some of the overland flow pathways start at manholes (or sewer inlets) locations. Thus, if a simplified version of the sewer network has less manholes (or sewer inlets) than the original one, the overland flow network will be consequently different. This paper compares different overland flow networks generated with different levels of sewer network skeletonisation. Sensitivity analysis is carried out in one catchment area in Coimbra, Portugal, in order to evaluate overland flow network characteristics.

  6. Lateral Flooding Associated to Wave Flood Generation on River Surface

    Science.gov (United States)

    Ramírez-Núñez, C.; Parrot, J.-F.

    2016-06-01

    This research provides a wave flood simulation using a high resolution LiDAR Digital Terrain Model. The simulation is based on the generation of waves of different amplitudes that modify the river level in such a way that water invades the adjacent areas. The proposed algorithm firstly reconstitutes the original river surface of the studied river section and then defines the percentage of water loss when the wave floods move downstream. This procedure was applied to a gently slope area in the lower basin of Coatzacoalcos river, Veracruz (Mexico) defining the successive areas where lateral flooding occurs on its downstream movement.

  7. Image Generation Using Bidirectional Integral Features for Face Recognition with a Single Sample per Person.

    Directory of Open Access Journals (Sweden)

    Yonggeol Lee

    Full Text Available In face recognition, most appearance-based methods require several images of each person to construct the feature space for recognition. However, in the real world it is difficult to collect multiple images per person, and in many cases there is only a single sample per person (SSPP. In this paper, we propose a method to generate new images with various illuminations from a single image taken under frontal illumination. Motivated by the integral image, which was developed for face detection, we extract the bidirectional integral feature (BIF to obtain the characteristics of the illumination condition at the time of the picture being taken. The experimental results for various face databases show that the proposed method results in improved recognition performance under illumination variation.

  8. Image Generation Using Bidirectional Integral Features for Face Recognition with a Single Sample per Person

    Science.gov (United States)

    Lee, Yonggeol; Lee, Minsik; Choi, Sang-Il

    2015-01-01

    In face recognition, most appearance-based methods require several images of each person to construct the feature space for recognition. However, in the real world it is difficult to collect multiple images per person, and in many cases there is only a single sample per person (SSPP). In this paper, we propose a method to generate new images with various illuminations from a single image taken under frontal illumination. Motivated by the integral image, which was developed for face detection, we extract the bidirectional integral feature (BIF) to obtain the characteristics of the illumination condition at the time of the picture being taken. The experimental results for various face databases show that the proposed method results in improved recognition performance under illumination variation. PMID:26414018

  9. Application of next generation sequencing to human gene fusion detection: computational tools, features and perspectives.

    Science.gov (United States)

    Wang, Qingguo; Xia, Junfeng; Jia, Peilin; Pao, William; Zhao, Zhongming

    2013-07-01

    Gene fusions are important genomic events in human cancer because their fusion gene products can drive the development of cancer and thus are potential prognostic tools or therapeutic targets in anti-cancer treatment. Major advancements have been made in computational approaches for fusion gene discovery over the past 3 years due to improvements and widespread applications of high-throughput next generation sequencing (NGS) technologies. To identify fusions from NGS data, existing methods typically leverage the strengths of both sequencing technologies and computational strategies. In this article, we review the NGS and computational features of existing methods for fusion gene detection and suggest directions for future development.

  10. Accurate single-sequence prediction of solvent accessible surface area using local and global features.

    Science.gov (United States)

    Faraggi, Eshel; Zhou, Yaoqi; Kloczkowski, Andrzej

    2014-11-01

    We present a new approach for predicting the Accessible Surface Area (ASA) using a General Neural Network (GENN). The novelty of the new approach lies in not using residue mutation profiles generated by multiple sequence alignments as descriptive inputs. Instead we use solely sequential window information and global features such as single-residue and two-residue compositions of the chain. The resulting predictor is both highly more efficient than sequence alignment-based predictors and of comparable accuracy to them. Introduction of the global inputs significantly helps achieve this comparable accuracy. The predictor, termed ASAquick, is tested on predicting the ASA of globular proteins and found to perform similarly well for so-called easy and hard cases indicating generalizability and possible usability for de-novo protein structure prediction. The source code and a Linux executables for GENN and ASAquick are available from Research and Information Systems at http://mamiris.com, from the SPARKS Lab at http://sparks-lab.org, and from the Battelle Center for Mathematical Medicine at http://mathmed.org.

  11. Accurate single-sequence prediction of solvent accessible surface area using local and global features

    Science.gov (United States)

    Faraggi, Eshel; Zhou, Yaoqi; Kloczkowski, Andrzej

    2014-01-01

    We present a new approach for predicting the Accessible Surface Area (ASA) using a General Neural Network (GENN). The novelty of the new approach lies in not using residue mutation profiles generated by multiple sequence alignments as descriptive inputs. Instead we use solely sequential window information and global features such as single-residue and two-residue compositions of the chain. The resulting predictor is both highly more efficient than sequence alignment based predictors and of comparable accuracy to them. Introduction of the global inputs significantly helps achieve this comparable accuracy. The predictor, termed ASAquick, is tested on predicting the ASA of globular proteins and found to perform similarly well for so-called easy and hard cases indicating generalizability and possible usability for de-novo protein structure prediction. The source code and a Linux executables for GENN and ASAquick are available from Research and Information Systems at http://mamiris.com, from the SPARKS Lab at http://sparks-lab.org, and from the Battelle Center for Mathematical Medicine at http://mathmed.org. PMID:25204636

  12. Structural Features of Boron-Doped Si(113) Surfaces Simulated by ab initio Calculations

    Institute of Scientific and Technical Information of China (English)

    LIAO Long-Zhong; LIU Zheng-Hui; ZHANG Zhao-Hui

    2008-01-01

    Based on ab initio calculations, boron-doped Si(113) surfaces have been simulated and atomic structures of the surfaces have been proposed. It has been determined that surface features of empty and filled states that are separately localized at pentamers and adatoms indicates a low surface density of B atoms, while it is attributed to heavy doping of B atoms at the second layer that pentamers and adatoms are both present in an image of scanning tunnelling microscopy. B doping at the second layer should be balanced by adsorbed B or Si atoms beside the adatoms and inserted B interstitials below the adatoms.

  13. Managing ambiguity in reference generation: the role of surface structure.

    Science.gov (United States)

    Khan, Imtiaz H; van Deemter, Kees; Ritchie, Graeme

    2012-04-01

    This article explores the role of surface ambiguities in referring expressions, and how the risk of such ambiguities should be taken into account by an algorithm that generates referring expressions, if these expressions are to be optimally effective for a hearer. We focus on the ambiguities that arise when adjectives occur in coordinated structures. The central idea is to use statistical information about lexical co-occurrence to estimate which interpretation of a phrase is most likely for human readers, and to avoid generating phrases where misunderstandings are likely. Various aspects of the problem were explored in three experiments in which responses by human participants provided evidence about which reading was most likely for certain phrases, which phrases were deemed most suitable for particular referents, and the speed at which various phrases were read. We found a preference for ''clear'' expressions to ''unclear'' ones, but if several of the expressions are ''clear,'' then brief expressions are preferred over non-brief ones even though the brief ones are syntactically ambiguous and the non-brief ones are not; the notion of clarity was made precise using Kilgarriff's Word Sketches. We outline an implemented algorithm that generates noun phrases conforming to our hypotheses.

  14. Evaluation of surface EMG features for the recognition of American Sign Language gestures.

    Science.gov (United States)

    Kosmidou, Vasiliki E; Hadjileontiadis, Leontios J; Panas, Stavros M

    2006-01-01

    In this work, analysis of the surface electromyogram (sEMG) signal is proposed for the recognition of American sign language (ASL) gestures. To this purpose, sixteen features are extracted from the sEMG signal acquired from the user's forearm, and evaluated by the Mahalanobis distance criterion. Discriminant analysis is used to reduce the number of features used in the classification of the signed ASL gestures. The proposed features are tested against noise resulting in a further reduced set of features, which are evaluated for their discriminant ability. The classification results reveal that 97.7% of the inspected ASL gestures were correctly recognized using sEMG-based features, providing a promising solution to the automatic ASL gesture recognition problem.

  15. Assessment of the Impact of Complex Healthcare Features on Construction Waste Generation

    Directory of Open Access Journals (Sweden)

    Niluka Domingo

    2015-08-01

    Full Text Available Over recent years, the British government has been investing billions of pounds in new and refurbished healthcare building projects. With the rapid growth in investment in healthcare infrastructure throughout the United Kingdom, a number of sustainability issues have been created, including construction waste generation. There is growing consensus in the literature that healthcare buildings are “complex”, due to their unique functional and operational features, and are thus more prone to generating larger amounts of construction waste. However, no significant research has been undertaken to identify the relationships between complex features in building projects and construction waste production, which is the focus of this study. Twenty-five semi-structured interviews and a questionnaire survey were conducted among healthcare clients, contractors, and architects. A life cycle approach has been adopted in this study to holistically assess and evaluate the effects of complexities with construction waste causes in healthcare projects. The findings reveal that the complex shapes and sizes of rooms, and mechanical and electrical services, significantly impact waste caused by such things as: incomplete briefing, incorrect drawing details, complex designs, non-standard designs, and inadequate communication and coordination in the pre-design, design, and construction stages.

  16. Differential geometry of the ruled surfaces optically generated by mirror scanning devices: II. Generation of helicoids and hyperbolic paraboloids.

    Science.gov (United States)

    Li, Yajun

    2011-06-01

    The theory developed in Part I of this study [Y. Li, "Differential geometry of the ruled surfaces optically generated by mirror-scanning devices. I. Intrinsic and extrinsic properties of the scan field," J. Opt. Soc. Am. A28, 667 (2011)] for the ruled surfaces optically generated by single-mirror scanning devices is extended to multimirror scanning systems for an investigation of optical generation of the well-known ruled surfaces, such as helicoid, Plücker's conoid, and hyperbolic paraboloid.

  17. Surface features on Sahara soil dust particles made visible by atomic force microscope (AFM phase images

    Directory of Open Access Journals (Sweden)

    M. O. Andreae

    2008-10-01

    Full Text Available We show that atomic force microscopy (AFM phase images can reveal surface features of soil dust particles, which are not evident using other microscopic methods. The non-contact AFM method is able to resolve topographical structures in the nanometer range as well as to uncover repulsive atomic forces and attractive van der Waals' forces, and thus gives insight to surface properties. Though the method does not allow quantitative assignment in terms of chemical compound description, it clearly shows deposits of distinguishable material on the surface. We apply this technique to dust aerosol particles from the Sahara collected over the Atlantic Ocean and describe micro-features on the surfaces of such particles.

  18. Surface features on Sahara soil dust particles made visible by atomic force microscope (AFM phase images

    Directory of Open Access Journals (Sweden)

    G. Helas

    2008-08-01

    Full Text Available We show that atomic force microscopy (AFM phase images can reveal surface features of soil dust particles, which are not evident using other microscopic methods. The non-contact AFM method is able to resolve topographical structures in the nanometer range as well as to uncover repulsive atomic forces and attractive van der Waals' forces, and thus gives insight to surface properties. Though the method does not allow quantitative assignment in terms of chemical compound description, it clearly shows deposits of distinguishable material on the surface. We apply this technique to dust aerosol particles from the Sahara collected over the Atlantic Ocean and describe micro-features on the surfaces of such particles.

  19. Extraction of bulk generation lifetime and surface generation velocity in high-resistivity silicon by means of gated diodes

    CERN Document Server

    Verzellesi, G; Bosisio, L; Dalla Betta, Gian Franco; Pignatel, Giogrio Umberto

    2002-01-01

    We show that the accuracy of the gated diode method for measuring bulk generation lifetime and surface generation velocity in high resistivity silicon depends critically on the gate length of the test device, as a result of nonidealities affecting the gated diode operation. Minimization of the surface generation velocity measurement error requires the gate length to be suitably decreased, while long gate length structures are needed for accurate bulk generation lifetime extraction.

  20. Surface features on Sahara soil dust particles made visible by atomic force microscope (AFM) phase images

    OpenAIRE

    Andreae, M. O.; G. Helas

    2008-01-01

    We show that atomic force microscopy (AFM) phase images can reveal surface features of soil dust particles, which are not evident using other microscopic methods. The non-contact AFM method is able to resolve topographical structures in the nanometer range as well as to uncover repulsive atomic forces and attractive van der Waals' forces, and thus gives insight to surface properties. Though the method does not allow quantitative assignment in terms of chemical compound description, it clearly...

  1. Interpretation of Impact Features on the Surface of the WFPC-2 Radiator

    Science.gov (United States)

    Anz-Meador, P. D.; Christiansen, Eric L.; Kou, J.-C.

    2011-01-01

    An examination of the Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC-2) radiator assembly was conducted at NASA Goddard Space Flight Center (GSFC) during the summer of 2009. Immediately apparent was the predominance of impact features resident only in the thermal paint layer; similar phenomenology was observed during a prior survey of the WFPC-1 radiator. As well, larger impact features displayed spallation zones, darkened areas, and other features not encountered in impacts onto bare surfaces. Whereas the characterization of impact features by depth and diameter on unpainted surfaces has been long established, the mitigation provided by the painted layer presented a challenge to further analysis of the WFPC-2 features; a literature search revealed no systematic characterization of the ballistic limit equations of painted or coated surfaces. In order to characterize the impactors responsible for the observed damage, an understanding of the cratering and spallation phenomenology of the painted surface was required. To address that challenge, NASA sponsored a series of hypervelocity calibration shots at the White Sands Test Facility (WSTF). This effort required the following activities: the production, painting, and artificial ageing of test coupons in a manner similar to the actual radiator; the determination of the test matrix parameters projectile diameter and material (mass density), impact velocity, and impact angle, so as to enable both an adequate characterization of the impact by projectile and impact geometry and support hydrocode modeling to fill in and extend the applicability of the calibration shots; the selection of suitable projectiles; logistics; and an analysis of feature characteristics upon return of the coupons. This paper reports the results of the test campaign and presents ballistic limit equations for painted surfaces. We also present initial results of our interpretation methodologies.

  2. Contributions of feature shapes and surface cues to the recognition of facial expressions.

    Science.gov (United States)

    Sormaz, Mladen; Young, Andrew W; Andrews, Timothy J

    2016-10-01

    Theoretical accounts of face processing often emphasise feature shapes as the primary visual cue to the recognition of facial expressions. However, changes in facial expression also affect the surface properties of the face. In this study, we investigated whether this surface information can also be used in the recognition of facial expression. First, participants identified facial expressions (fear, anger, disgust, sadness, happiness) from images that were manipulated such that they varied mainly in shape or mainly in surface properties. We found that the categorization of facial expression is possible in either type of image, but that different expressions are relatively dependent on surface or shape properties. Next, we investigated the relative contributions of shape and surface information to the categorization of facial expressions. This employed a complementary method that involved combining the surface properties of one expression with the shape properties from a different expression. Our results showed that the categorization of facial expressions in these hybrid images was equally dependent on the surface and shape properties of the image. Together, these findings provide a direct demonstration that both feature shape and surface information make significant contributions to the recognition of facial expressions.

  3. Correlation between fat content and features of generative growth of arabesque greenling Pleurogrammus azonus

    Directory of Open Access Journals (Sweden)

    Alexander Vdovin

    2014-09-01

    Full Text Available Objective: To determine the correlation between fat content and features of generative growth of arabesque greenling Pleurogrammus azonus. Methods: The samples were collected by bottom trawl during trawl surveys of research vessel MRS-055 conducted by TINRO-Center in Peter the Great Bay (Sea of Japan. A total of 332 individuals of arabesque greenling were analyzed. Fat content was determined by the standard method of extraction by sulfuric ether from the dry rest. Results: The most part of deposit fat of arabesque greenling is concentrated in muscles and hypodermis: 86.2%-97.0% (mean value 92.3% of the total deposited fat mass. The liver fat was 1.1%-7.7% (mean value 4.8% and the internal fat was 0.9%-5.2% (mean value 2.8% of the total mass. Decreasing of the muscles fat was observed at sudden changes of qualitative and quantitative characteristics of sexual products, and for immature fish the relation between accumulation of fat in muscles and generative growth was not found. Conclusions: Dynamics of fat in liver corresponds closely with the processes of generative growth, and increasing of gonads weight causes decreasing of liver fat content, both for mature and immature fish.

  4. Correlation between fat content and features of generative growth of arabesque greenling Pleurogrammus azonus

    Institute of Scientific and Technical Information of China (English)

    Alexander Vdovin; Dmitry Antonenko

    2014-01-01

    Objective: To determine the correlation between fat content and features of generative growth of arabesque greenling Pleurogrammus azonus.Methods:The samples were collected by bottom trawl during trawl surveys of research vessel MRS-055 conducted by TINRO-Center in Peter the Great Bay (Sea of Japan). A total of 332 individuals of arabesque greenling were analyzed. Fat content was determined by the standard method of extraction by sulfuric ether from the dry rest. Results: The most part of deposit fat of arabesque greenling is concentrated in muscles and hypodermis: 86.2%-97.0% (mean value 92.3%) of the total deposited fat mass. The liver fat was 1.1%-7.7% (mean value 4.8%) and the internal fat was 0.9%-5.2% (mean value 2.8%) of the total mass. Decreasing of the muscles fat was observed at sudden changes of qualitative and quantitative characteristics of sexual products, and for immature fish the relation between accumulation of fat in muscles and generative growth was not found.Conclusions:Dynamics of fat in liver corresponds closely with the processes of generative growth, and increasing of gonads weight causes decreasing of liver fat content, both for mature and immature fish.

  5. Meteosat Third Generation Lightning Imager: a discussion on user requirements and instrument features.

    Science.gov (United States)

    Biron, D.; de Leonibus, L.; Zauli, F.; Melfi, D.; Laquale, P.; Labate, D.

    2009-04-01

    For the next generation of earth observation geostationary satellite, major operating agencies are planning to insert an optical imaging mission, that continuously observes lightning pulses in the atmosphere; EUMETSAT has decided at the end of 2008 that one of the mission to be flown on MTG is LI, a Lightning Imager. The Centro Nazionale di Meteorologia e Climatologia Aeronautica recently hosted a fellowship sponsored by Selex Galileo, with the intent to study and perform a simulation of Meteosat Third Generation - Lightning Imager (MTG-LI) sensor behavior through Tropical Rainfall Measuring Mission - Lightning Imaging Sensor data (TRMM-LIS). MTG-LI mission has no Meteosat Second Generation heritage, but users need to evaluate the possible real time data output of the instrument to agree in inserting it on MTG payload. Authors took the expected LI design from MTG Mission Requirement Document, and reprocess real lightning dataset, acquired from space by TRMM-LIS instrument, to produce a simulated MTG-LI lightning dataset. The simulation is performed in several run, varying Minimum Detectable Energy, taking into account processing steps from event detection to final lightning information. A discussion on user requirements and instrument features is presented.

  6. Surface plasma source with saddle antenna radio frequency plasma generator.

    Science.gov (United States)

    Dudnikov, V; Johnson, R P; Murray, S; Pennisi, T; Piller, C; Santana, M; Stockli, M; Welton, R

    2012-02-01

    A prototype RF H(-) surface plasma source (SPS) with saddle (SA) RF antenna is developed which will provide better power efficiency for high pulsed and average current, higher brightness with longer lifetime and higher reliability. Several versions of new plasma generators with small AlN discharge chambers and different antennas and magnetic field configurations were tested in the plasma source test stand. A prototype SA SPS was installed in the Spallation Neutron Source (SNS) ion source test stand with a larger, normal-sized SNS AlN chamber that achieved unanalyzed peak currents of up to 67 mA with an apparent efficiency up to 1.6 mA∕kW. Control experiments with H(-) beam produced by SNS SPS with internal and external antennas were conducted. A new version of the RF triggering plasma gun has been designed. A saddle antenna SPS with water cooling is fabricated for high duty factor testing.

  7. Generation of a crowned pinion tooth surface by a surface of revolution

    Science.gov (United States)

    Litvin, F. L.; Zhang, J.; Handschuh, R. F.

    1988-01-01

    A method of generating crowned pinion tooth surfaces using a surface of revolution is developed. The crowned pinion meshes with a regular involute gear and has a prescribed parabolic type of transmission errors when the gears operate in the aligned mode. When the gears are misaligned the transmission error remains parabolic with the maximum level still remaining very small (less than 0.34 arc sec for the numerical examples). Tooth contact analysis (TCA) is used to simulate the conditions of meshing, determine the transmission error, and determine the bearing contact.

  8. Numerical study of surface water waves generated by mass movement

    Energy Technology Data Exchange (ETDEWEB)

    Ghozlani, Belgacem; Hafsia, Zouhaier; Maalel, Khlifa, E-mail: ghozlanib@yahoo.fr [Ecole Nationale d' Ingenieurs de Tunis, Laboratoire de Modelisation en ' Hydraulique et Environnement, BP 37, Le Belvedere, 1002 Tunis (Tunisia)

    2013-10-01

    In this paper waves generated by two-dimensional mass movement are simulated using a numerical model based on the full hydrodynamic coupling between rigid-body motion and ambient fluid flow. This approach has the capability to represent the dynamics of the moving rigid body, which avoids the need to prescribe the body velocity based on the data measurements. This model is implemented in the CFX code and uses the Reynolds average Navier-Stokes equations solver coupled to the recently developed immersed solid technique. The latter technique allows us to follow implicitly the motion of the solid block based on the rigid body solver. The volume-of-fluid method is used to track the free surface locations. The accuracy of the present model is firstly examined against the simple physical case of a freely falling rigid body into water reproducing Scott Russell's solitary waves. More complex and realistic simulations of aerial and submarine mass-movement, simulated by a rigid wedge sliding into water along a 45 Degree-Sign slope, are then performed. Simulated results of the aerial mass movement show the complex flow patterns in terms of the velocity fields and free surface profiles. Results are in good agreement with the available experimental data. In addition, the physical processes associated with the generation of water wave by two-dimensional submarine mass-movement are explored. The effects of the initial submergence and specific gravity on the slide mass kinematics and maximum wave amplitude are investigated. The terminal velocity and initial acceleration of the slide mass are well predicted when compared to experimental results. It is found that the initial submergence did not have a significant effect on the initial acceleration of the slide block centre of mass. However, it depends nonlinearly on the specific gravity. The maximum wave amplitude and the time at which it occurred are also presented as a function of the initial submergence and specific gravity

  9. Numerical study of surface water waves generated by mass movement

    Science.gov (United States)

    Ghozlani, Belgacem; Hafsia, Zouhaier; Maalel, Khlifa

    2013-10-01

    In this paper waves generated by two-dimensional mass movement are simulated using a numerical model based on the full hydrodynamic coupling between rigid-body motion and ambient fluid flow. This approach has the capability to represent the dynamics of the moving rigid body, which avoids the need to prescribe the body velocity based on the data measurements. This model is implemented in the CFX code and uses the Reynolds average Navier-Stokes equations solver coupled to the recently developed immersed solid technique. The latter technique allows us to follow implicitly the motion of the solid block based on the rigid body solver. The volume-of-fluid method is used to track the free surface locations. The accuracy of the present model is firstly examined against the simple physical case of a freely falling rigid body into water reproducing Scott Russell's solitary waves. More complex and realistic simulations of aerial and submarine mass-movement, simulated by a rigid wedge sliding into water along a 45° slope, are then performed. Simulated results of the aerial mass movement show the complex flow patterns in terms of the velocity fields and free surface profiles. Results are in good agreement with the available experimental data. In addition, the physical processes associated with the generation of water wave by two-dimensional submarine mass-movement are explored. The effects of the initial submergence and specific gravity on the slide mass kinematics and maximum wave amplitude are investigated. The terminal velocity and initial acceleration of the slide mass are well predicted when compared to experimental results. It is found that the initial submergence did not have a significant effect on the initial acceleration of the slide block centre of mass. However, it depends nonlinearly\\vadjust{\

  10. A novel approach to generate random surface thermal loads in piping

    Energy Technology Data Exchange (ETDEWEB)

    Costa Garrido, Oriol, E-mail: oriol.costa@ijs.si; El Shawish, Samir; Cizelj, Leon

    2014-07-01

    Highlights: • Approach for generating continuous and time-dependent random thermal fields. • Temperature fields simulate fluid mixing thermal loads at fluid–wall interface. • Through plane-wave decomposition, experimental temperature statistics are reproduced. • Validation of the approach with a case study from literature. • Random surface thermal loads generation for future thermal fatigue analyses of piping. - Abstract: There is a need to perform three-dimensional mechanical analyses of pipes, subjected to complex thermo-mechanical loadings such as the ones evolving from turbulent fluid mixing in a T-junction. A novel approach is proposed in this paper for fast and reliable generation of random thermal loads at the pipe surface. The resultant continuous and time-dependent temperature fields simulate the fluid mixing thermal loads at the fluid–wall interface. The approach is based on reproducing discrete fluid temperature statistics, from experimental readings or computational fluid dynamic simulation's results, at interface locations through plane-wave decomposition of temperature fluctuations. The obtained random thermal fields contain large scale instabilities such as cold and hot spots traveling at flow velocities. These low frequency instabilities are believed to be among the major causes of the thermal fatigue in T-junction configurations. The case study found in the literature has been used to demonstrate the generation of random surface thermal loads. The thermal fields generated with the proposed approach are statistically equivalent (within the first two moments) to those from CFD simulations results of similar characteristics. The fields maintain the input data at field locations for a large set of parameters used to generate the thermal loads. This feature will be of great advantage in future sensitivity fatigue analyses of three-dimensional pipe structures.

  11. Marshall Space Flight Center surface modeling and grid generation applications

    Science.gov (United States)

    Williams, Robert W.; Benjamin, Theodore G.; Cornelison, Joni W.

    1995-03-01

    The Solid Rocket Motors (SRM) used by NASA to propel the Space Shuttle employ gimballing nozzles as a means for vehicular guidance during launch and ascent. Gimballing a nozzle renders the pressure field of the exhaust gases nonaxisymmetric. This has two effects: (1) it exerts a torque and side load on the nozzle; and (2) the exhaust gases flow circumferentially in the aft-dome region, thermally loading the flexible boot, case-to-nozzle joint, and casing insulation. The use of CFD models to simulate such flows is imperative in order to assess SRM design. The grids for these problems were constructed by obtaining information from drawings and tabulated coordinates. The 2D axisymmetric grids were designed and generated using the EZ-Surf and GEN2D surface and grid generation codes. These 2D grids were solved using codes such as FDNS, GASP, and MINT. These axisymmetric grids were rotated around the center-line to form 3D nongimballed grids. These were then gimballed around the pivot point and the gaps or overlaps resurfaced to obtain the final domains, which contained approximately 366,000 grid points. The 2D solutions were then rotated and manipulated as appropriate for geometry and used as initial guesses in the final solution. The analyses were used in answering questions about flight criteria.

  12. Study of Dynamic Features of Surface Plasma in High-Power Disk Laser Welding

    Institute of Scientific and Technical Information of China (English)

    王腾; 高向东; Katayatna SEIJI; 金小莉

    2012-01-01

    High-speed photography was used to obtain the dynamic changes in the surface plasma during a high-power disk laser welding process. A color space clustering algorithm to extract the edge information of the surface plasma region was developed in order to improve the accuracy of image processing. With a comparative analysis of the plasma features, i.e., area and height, and the characteristics of the welded seam, the relationship between the surface plasma and the stability of the laser welding process was characterized, which provides a basic understanding for the real-time monitoring of laser welding.

  13. Generation of Focused Electric Field Patterns at Dielectric Surfaces

    Science.gov (United States)

    Olofsson, Jessica; Levin, Mikael; Strömberg, Anette; Weber, Stephen G.; Ryttsén, Frida; Orwar, Owe

    2006-01-01

    We here report on a concept for creating well-defined electric field gradients between the boundaries of capillary electrode (a capillary of a nonconducting material equipped with an interior metal electrode) outlets, and dielectric surfaces. By keeping a capillary electrode opening close to a boundary between a conducting solution and a nonconducting medium, a high electric field can be created close to the interface by field focusing effects. By varying the inner and outer diameters of the capillary, the span of electric field strengths and the field gradient obtained can be controlled, and by varying the slit height between the capillary rim and the surface, or the applied current, the average field strength and gradient can be varied. Field focusing effects and generation of electric field patterns were analyzed using finite element method simulations. We experimentally verified the method by electroporation of a fluorescent dye (fluorescein diphosphate) into adherent, monolayered cells (PC-12 and WSS-1) and obtained a pattern of fluorescent cells corresponding to the focused electric field. PMID:16013887

  14. FaceTOON: a unified platform for feature-based cartoon expression generation

    Science.gov (United States)

    Zaharia, Titus; Marre, Olivier; Prêteux, Françoise; Monjaux, Perrine

    2008-02-01

    This paper presents the FaceTOON system, a semi-automatic platform dedicated to the creation of verbal and emotional facial expressions, within the applicative framework of 2D cartoon production. The proposed FaceTOON platform makes it possible to rapidly create 3D facial animations with a minimum amount of user interaction. In contrast with existing commercial 3D modeling softwares, which usually require from the users advanced 3D graphics skills and competences, the FaceTOON system is based exclusively on 2D interaction mechanisms, the 3D modeling stage being completely transparent for the user. The system takes as input a neutral 3D face model, free of any facial feature, and a set of 2D drawings, representing the desired facial features. A 2D/3D virtual mapping procedure makes it possible to obtain a ready-for-animation model which can be directly manipulated and deformed for generating expressions. The platform includes a complete set of dedicated tools for 2D/3D interactive deformation, pose management, key-frame interpolation and MPEG-4 compliant animation and rendering. The proposed FaceTOON system is currently considered for industrial evaluation and commercialization by the Quadraxis company.

  15. Generation of nanometer structures on surfaces of ionic solids generated by laser and electron beam irradiation

    Science.gov (United States)

    Dawes, M. L.; Langford, S. C.; Dickinson, J. Thomas

    2001-03-01

    Radiation effects on hydrated single crystals are poorly understood. We find that dense arrays of nanoscale conical structures, with aspect ratios on the order of 200, are produced when single crystal brushite (CaHPO_4^.2H_2O) is exposed to energetic electrons (2 keV). Other three dimensional nanostructures are generated by exposing brushite to excimer laser irradiation. We show that the mechanism involves: (a) photo/electron stimulated decomposition of the matrix, and (b) thermally stimulated migration of water (in this case, crystalline) and ionic material. We have isolated these factors to some extent and present plausible mechanisms for structure formation. In addition, we have recently exposed non-hydrated ionic crystals to radiation in the presence of background water (pp_water ~ 10-7 Torr), which produces exceedingly fine structures (sub-10 nm). The optical and luminescence properties of these features will be presented. An example of a “stealth surface” will be given with possible applications for the laser generation of x-rays.

  16. Effect of surface topographic features on the optical properties of skin: a phantom study

    Science.gov (United States)

    Liu, Guangli; Chen, Jianfeng; Zhao, Zuhua; Zhao, Gang; Dong, Erbao; Chu, Jiaru; Xu, Ronald X.

    2016-10-01

    Tissue-simulating phantoms are used to validate and calibrate optical imaging systems and to understand light transport in biological tissue. Light propagation in a strongly turbid medium such as skin tissue experiences multiple scattering and diffuse reflection from the surface. Surface roughness introduces phase shifts and optical path length differences for light which is scattered within the skin tissue and reflected from the surface. In this paper, we study the effect of mismatched surface roughness on optical measurement and subsequent determination of optical properties of skin tissue. A series of phantoms with controlled surface features and optical properties corresponding to normal human skin are fabricated. The fabrication of polydimethylsiloxane (PDMS) phantoms with known surface roughness follows a standard soft lithography process. Surface roughness of skin-simulating phantoms are measured with Bruker stylus profiler. The diffuse reflectance of the phantom is validated by a UV/VIS spectrophotometer. The results show that surface texture and roughness have considerable influence on the optical characteristics of skin. This study suggests that surface roughness should be considered as an important contributing factor for the determination of tissue optical properties.

  17. Ion microprobe elemental analyses of impact features on interplanetary dust experiment sensor surfaces

    Science.gov (United States)

    Hunter, Jerry L.; Wortman, Jim J.; Griffis, Dieter P.; Simon, Charles G.

    1991-01-01

    Hypervelocity impact features on several of the electro-active dust sensors utilized in the Interplanetary Dust Experiment (IDE) were subjected to elemental analysis using an ion microprobe. The negatively biased dust sensor surfaces acted as ion traps for cations produced in the plasma plumes of impacting particles. Impactor residue surrounds most impact features to two or three feature diameters. After etching away a layer of carbonaceous/silicaceous surface contamination, low mass resolution elemental survey scans are used to tentatively identify the presence of impactor debris. High mass resolution two-dimensional elemental maps and three dimensional depth profiling of the feature and surrounding area show the distribution and relative composition of the debris. The location of these sensors on the six primary Long Duration Exposure Facility (LDEF) sides provides a unique opportunity to further define the debris environment. Researchers applied the same techniques to impact and contaminant features on a set of ultra-pure, highly polished single crystal germanium wafer witness plates that were mounted on row 12 and exposed to the environment during the entire mission.

  18. Characterization and optimization of illumination vector for contouring surface form and feature using DSPI

    Science.gov (United States)

    Song, Chaolong; Prasad A. S., Guru; Chan, Kelvin H. K.; Murukeshan, Vadakke Matham

    2016-06-01

    Surface defect or damage is one of the critical factors leading to the failure of engineering materials and structures. The methodologies for the measurement of surface shape and feature or defect have been extensively explored and developed over the past few decades, including both contact and non-contact methods. Speckle pattern interferometry, as a non-contact optical method, has been demonstrated to effectively contour the surface shape through adjusting the illumination vector. However, few studies have been made to investigate the effect of the initial position of the illumination source as well as the source translation direction. In this paper, we report to carry out a study of measuring the surface form and feature using digital speckle pattern interferometry system via a slight translation of illumination source. Through theoretically analyzing the sensitivity factor along with the experimental validation, it is shown that the contouring fringe is more sensitive to the surface height with an off-axis illumination than the paraxial illumination. It is also found that translating the source along axial and lateral direction can be both used for the surface shape re-construction.

  19. The third generation multi-purpose plasma immersion ion implanter for surface modification of materials

    CERN Document Server

    Tang Bao Yin; Wang Xiao Feng; Gan Kong Yin; Wang Song Yan; Chu, P K; Huang Nian Ning; Sun Hong

    2002-01-01

    The third generation multi-purpose plasma immersion ion implantation (PIII) equipment has been successfully used for research and development of surface modification of biomedical materials, metals and their alloys in the Southwest Jiaotong University. The implanter equipped with intense current, pulsed cathodic arc metal plasma sources which have both strong coating function and gas and metal ion implantation function. Its pulse high voltage power supply can provide big output current. It can acquire very good implantation dose uniformity. The equipment can both perform ion implantation and combine ion implantation with sputtering deposition and coating to form many kinds of synthetic surface modification techniques. The main design principles, features of important components and achievement of research works in recent time have been described

  20. Uncertainty of diagnostic features measured by laser vibrometry: The case of optically non-cooperative surfaces

    Science.gov (United States)

    Agostinelli, G.; Paone, N.

    2012-12-01

    This paper discusses the uncertainty in the measurement of characteristic features by laser Doppler vibrometry useful to industrial diagnostics when measuring on polished, highly reflective, low diffusive surfaces, such as the enamelled metal sheet of the cabinet of electrical household appliances. This case is relevant to on-line quality control applications, where it is not possible to adopt any surface treatment to improve optical scattering properties. The paper illustrates in particular the effect of drop-out noise on the measured vibration signal and develops a joint analysis of drop-out noise due to poor optical properties and its effect on the diagnostic process, presented in statistical terms. A non-dimensional quantity is introduced to describe the amplitude of the Doppler signal and the presence of drop-out noise is shown to be correlated to its amplitude. Starting from the consideration that drop-out noise is impulsive, with a pseudo-random occurrence, this paper presents an experimental assessment of uncertainty in the measurement of some spectral features used for the diagnosis of electrical appliances on the production line. It can be seen that the effect of drop-out leads to an increase in scatter and to a systematic shift in the distribution of the features examined; this effect is relatively larger for features with low amplitude. The Monte Carlo simulation of measurement uncertainty propagation confirms the same trend and allows statistical distributions to be obtained for the features, thereby enabling us to draw some conclusions as regards diagnostic errors. This study shows that in the presence of pseudo-random drop-out noise a diagnosis based on spectral features with low amplitude has poor reliability and false-positives are highly probable. An analysis of this occurrence is made for cases of production exhibiting features with different statistical distributions and possible actions to limit such problem are highlighted.

  1. Decreased lung carcinoma cell density on select polymer nanometer surface features for lung replacement therapies

    Directory of Open Access Journals (Sweden)

    Lijuan Zhang

    2010-04-01

    Full Text Available Lijuan Zhang1, Young Wook Chun2, Thomas J Webster21Department of Chemistry and 2Division of Engineering, Brown University, Providence, RI USAAbstract: Poly(lactic-co-glycolic acid (PLGA has been widely used as a biomaterial in regenerative medicine because of its biocompatibility and biodegradability properties. Previous studies have shown that cells (such as bladder smooth muscle cells, chondrocytes, and osteoblasts respond differently to nanostructured PLGA surfaces compared with nanosmooth surfaces. The purpose of the present in vitro research was to prepare PLGA films with various nanometer surface features and determine whether lung cancer epithelial cells respond differently to such topographies. To create nanosurface features on PLGA, different sized (190 nm, 300 nm, 400 nm, and 530 nm diameter polystyrene beads were used to cast polydimethylsiloxane (PDMS molds which were used as templates to create nanofeatured PLGA films. Atomic force microscopy (AFM images and root mean square roughness (RMS values indicated that the intended spherical surface nanotopographies on PLGA with RMS values of 2.23, 5.03, 5.42, and 36.90 nm were formed by employing 190, 300, 400, and 530 nm beads. A solution evaporation method was also utilized to modify PLGA surface features by using 8 wt% (to obtain an AFM RMS value of 0.62 nm and 4 wt% (to obtain an AFM RMS value of 2.23 nm PLGA in chloroform solutions. Most importantly, lung cancer epithelial cells adhered less on the PLGA surfaces with RMS values of 0.62, 2.23, and 5.42 nm after four hours of culture compared with any other PLGA surface created here. After three days, PLGA surfaces with an RMS value of 0.62 nm had much lower cell density than any other sample. In this manner, PLGA with specific nanometer surface features may inhibit lung cancer cell density which may provide an important biomaterial for the treatment of lung cancer (from drug delivery to regenerative medicine.Keywords: nanotechnology

  2. Thermal Behaviour of Unusual Local-Scale Surface Features on Vesta

    Science.gov (United States)

    Tosi, F.; Capria, M. T.; De Sanctis, M. C.; Palomba, E.; Grassi, D.; Capaccioni, F.; Ammannito, E.; Combe, J.-Ph.; Sunshine, J. M.; McCord, T. B.; Titus, T. N.; Russell, C. T.; Raymond, C. A.; Mittlefehldt, D. W.; Toplis, M. J.; Forni, O.; Sykes, M. V.

    2012-01-01

    On Vesta, the region of the infrared spectrum beyond approximately 3.5 micrometers is dominated by the thermal emission of the asteroid's surface, which can be used to determine surface temperature by means of temperature-retrieval algorithms. The thermal behavior of areas of unusual albedo seen at the local scale can be related to physical properties that can provide information about the origin of those materials. Dawn's Visible and Infrared Mapping Spectrometer (VIR) hyperspectral cubes are used to retrieve surface temperatures, with high accuracy as long as temperatures are greater than 180 K. Data acquired in the Survey phase (23 July through 29 August 2011) show several unusual surface features: 1) high-albedo (bright) and low-albedo (dark) material deposits, 2) spectrally distinct ejecta, 3) regions suggesting finer-grained materials. Some of the unusual dark and bright features were re-observed by VIR in the subsequent High-Altitude Mapping Orbit (HAMO) and Low-Altitude Mapping Orbit (LAMO) phases at increased pixel resolution. To calculate surface temperatures, we applied a Bayesian approach to nonlinear inversion based on the Kirchhoff law and the Planck function. These results were cross-checked through application of alternative methods. Here we present temperature maps of several local-scale features that were observed by Dawn under different illumination conditions and different local solar times. Some bright terrains have an overall albedo in the visible as much as 40% brighter than surrounding areas. Data from the IR channel of VIR show that bright regions generally correspond to regions with lower thermal emission, i.e. lower temperature, while dark regions correspond to areas with higher thermal emission, i.e. higher temperature. This behavior confirms that many of the dark appearances in the VIS mainly reflect albedo variations. In particular, it is shown that during maximum daily insolation, dark features in the equatorial region may rise to

  3. Generation of 3-D surface maps in waste storage silos using a structured light source

    Science.gov (United States)

    Burks, B. L.; Rowe, J. C.; Dinkins, M. A.; Christensen, B.; Selleck, C.; Jacoboski, D.; Markus, R.

    1992-01-01

    Surface contours inside the large waste storage tanks typical of the Department of Energy (DOE) complex are, in general, highly irregular. In addition to pipes and other pieces of equipment in the tanks, the surfaces may have features such as mounds, fissures, crystalline structures, and mixed solid and liquid forms. Prior to remediation activities, it will be necessary to characterize the waste to determine the most effective remediation approaches. Surface contour data will be required both prior to and during remediation. The use is described of a structured light source to generate 3-D surface contour maps of the interior of waste storage silos at the Feed Materials Production Center at Fernald, OH. The landscape inside these large waste storage tanks bears a strong resemblance to some of the landscapes that might be encountered during lunar or planetary exploration. Hence, these terrestrial 3-D mapping techniques may be directly applicable to extraterrestrial exploration. In further development, it will be demonstrated that these 3-D data can be used for robotic task planning just as 3-D surface contour data of a satellite could be used to plan maintenance tasks for a space-based servicing robot.

  4. Thermal infrared remote sensing of surface features for renewable resource applications

    Science.gov (United States)

    Welker, J. E.

    1981-01-01

    The subjects of infrared remote sensing of surface features for renewable resource applications is reviewed with respect to the basic physical concepts involved at the Earth's surface and up through the atmosphere, as well as the historical development of satellite systems which produce such data at increasingly greater spatial resolution. With this general background in hand, the growth of a variety of specific renewable resource applications using the developing thermal infrared technology are discussed, including data from HCMM investigators. Recommendations are made for continued growth in this field of applications.

  5. Formation of Combined Surface Features of Protrusion Array and Wrinkles atop Shape-Memory Polymer

    Science.gov (United States)

    Sun, L.; Zhao, Y.; Huang, W. M.; Tong, T. H.

    We demonstrate a simple and cost-effective approach to realize two combined surface features of different scales together, namely submillimeter-sized protrusion array and microwrinkles, atop a polystyrene shape-memory polymer. Two different types of protrusions, namely flat-top protrusion and crown-shaped protrusion, were studied. The array of protrusions was produced by the Indentation-Polishing-Heating (IPH) process. Compactly packed steel balls were used for making array of indents. A thin gold layer was sputter deposited atop the polymer surface right after polishing. After heating for shape recovery, array of protrusions with wrinkles on the top due to the buckling of gold layer was produced.

  6. Comparison of Surface Flow Features from Lidar-Derived Digital Elevation Models with Historical Elevation and Hydrography Data for Minnehaha County, South Dakota

    Science.gov (United States)

    Poppenga, Sandra K.; Worstell, Bruce B.; Stoker, Jason M.; Greenlee, Susan K.

    2009-01-01

    The U.S. Geological Survey (USGS) has taken the lead in the creation of a valuable remote sensing product by incorporating digital elevation models (DEMs) derived from Light Detection and Ranging (lidar) into the National Elevation Dataset (NED), the elevation layer of 'The National Map'. High-resolution lidar-derived DEMs provide the accuracy needed to systematically quantify and fully integrate surface flow including flow direction, flow accumulation, sinks, slope, and a dense drainage network. In 2008, 1-meter resolution lidar data were acquired in Minnehaha County, South Dakota. The acquisition was a collaborative effort between Minnehaha County, the city of Sioux Falls, and the USGS Earth Resources Observation and Science (EROS) Center. With the newly acquired lidar data, USGS scientists generated high-resolution DEMs and surface flow features. This report compares lidar-derived surface flow features in Minnehaha County to 30- and 10-meter elevation data previously incorporated in the NED and ancillary hydrography datasets. Surface flow features generated from lidar-derived DEMs are consistently integrated with elevation and are important in understanding surface-water movement to better detect surface-water runoff, flood inundation, and erosion. Many topographic and hydrologic applications will benefit from the increased availability of accurate, high-quality, and high-resolution surface-water data. The remotely sensed data provide topographic information and data integration capabilities needed for meeting current and future human and environmental needs.

  7. Constraints on the lithospheric structure of Venus from mechanical models and tectonic surface features

    Science.gov (United States)

    Zuber, Maria T.

    1987-01-01

    The evidence for the extensional or compressional origins of some prominent Venusian surface features disclosed by radar images is discussed. Using simple models, the hypothesis that the observed length scales (10-20 km and 100-300 km) of deformations are controlled by dominant wavelengths arising from unstable compression or extension of the Venus lithosphere is tested. The results show that the existence of tectonic features that exhibit both length scales can be explained if, at the time of deformation, the lithosphere consisted of a crust that was relatively strong near the surface and weak at its base, and an upper mantle that was stronger than or nearly comparable in strength to the upper crust.

  8. Thermal Analysis of Unusual Local-scale Features on the Surface of Vesta

    Science.gov (United States)

    Tosi, F.; Capria, M. T.; DeSanctis, M. C.; Capaccioni, F.; Palomba, E.; Zambon, F.; Ammannito, E.; Blewett, D. T.; Combe, J.-Ph.; Denevi, B. W.; Li, J.-Y.; Mittlefehldt, D. W.; Palmer, E.; Sunshine, J. M.; Titus, T. N.; Raymond, C. A.; Russell, C. T.

    2013-01-01

    At 525 km in mean diameter, Vesta is the second-most massive object in the main asteroid belt of our Solar System. At all scales, pyroxene absorptions are the most prominent spectral features on Vesta and overall, Vesta mineralogy indicates a complex magmatic evolution that led to a differentiated crust and mantle [1]. The thermal behavior of areas of unusual albedo seen on the surface at the local scale can be related to physical properties that can provide information about the origin of those materials. Dawn's Visible and Infrared Mapping Spectrometer (VIR) [2] hyperspectral images are routinely used, by means of temperature-retrieval algorithms, to compute surface temperatures along with spectral emissivities. Here we present temperature maps of several local-scale features of Vesta that were observed by Dawn under different illumination conditions and different local solar times.

  9. Surface features of central North America: a synoptic view from computer graphics

    Science.gov (United States)

    Pike, R.J.

    1991-01-01

    A digital shaded-relief image of the 48 contiguous United States shows the details of large- and small-scale landforms, including several linear trends. The features faithfully reflect tectonism, continental glaciation, fluvial activity, volcanism, and other surface-shaping events and processes. The new map not only depicts topography accurately and in its true complexity, but does so in one synoptic view that provides a regional context for geologic analysis unobscured by clouds, culture, vegetation, or artistic constraints. -Author

  10. Memory for surface features of unfamiliar melodies: independent effects of changes in pitch and tempo.

    Science.gov (United States)

    Schellenberg, E Glenn; Stalinski, Stephanie M; Marks, Bradley M

    2014-01-01

    A melody's identity is determined by relations between consecutive tones in terms of pitch and duration, whereas surface features (i.e., pitch level or key, tempo, and timbre) are irrelevant. Although surface features of highly familiar recordings are encoded into memory, little is known about listeners' mental representations of melodies heard once or twice. It is also unknown whether musical pitch is represented additively or interactively with temporal information. In two experiments, listeners heard unfamiliar melodies twice in an initial exposure phase. In a subsequent test phase, they heard the same (old) melodies interspersed with new melodies. Some of the old melodies were shifted in key, tempo, or key and tempo. Listeners' task was to rate how well they recognized each melody from the exposure phase while ignoring changes in key and tempo. Recognition ratings were higher for old melodies that stayed the same compared to those that were shifted in key or tempo, and detrimental effects of key and tempo changes were additive in between-subjects (Experiment 1) and within-subjects (Experiment 2) designs. The results confirm that surface features are remembered for melodies heard only twice. They also imply that key and tempo are processed and stored independently.

  11. THE BALNEARY RESOURCE, A GENERATOR OF BUILT HERITAGE. THE STRATIGRAPHIC FEATURES OF HERCULANE BATHS

    Directory of Open Access Journals (Sweden)

    S. SPÂNU

    2012-03-01

    Full Text Available The balneary resource, a generator of built heritage. The stratigraphic features of Herculane Baths. The exploitation of natural resources, regardless of type, usually consists of two phases: firstly, the development of exploitation processes and secondly the development of exploitation structures – elements or built structures intended for the processing of the concerned natural resources. Many such structures have been declared architectural heritage monuments due to their historical, documentary, representative and aesthetical value, examples being numerous and varied. Water is the main resource that dictates the occurrence and development of human settlements and creates various typologies that derive from the accessibility, exploitation methods, and adaptation to the conditions and characteristics of the resource. With a peculiar evolution in terms of the dynamics of the binomial composed of natural resource and architectural heritage resource, mineral resources (especially balneal waters fall in a distinct category: although mainly utilitarian in function, they have also cultural, aesthetic and even religious purposes. Besides their curative properties, spa mineral waters can be used as is, in many cases directly from the source, this being the explanation why they have generated such great and continuous interest - forming today a highly stratified built heritage background. Keeping in mind the sustainable development for a medium or a long period of time, an analysis of the interrelations between the balneal natural resource and the deriving architectural heritage is necessary. The purpose of such analysis is determining the limitations of exploitation and identifying the optimal means of safeguarding both elements, the natural water resource and the anthropogenic one, for a more rational territory management.

  12. Surface and morphological features of laser-irradiated silicon under vacuum, nitrogen and ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Hayat, Asma, E-mail: asmahayat@gcu.edu.pk; Bashir, Shazia; Akram, Mahreen; Mahmood, Khaliq; Iqbal, Muhammad Hassan

    2015-12-01

    Highlights: • Laser irradiation effects on Si surface have been explored. • An Excimer Laser was used as a source. • SEM analysis was performed to explore surface morphology. • Raman spectroscopy analysis was carried out to find crystallographical alterations. - Abstract: Laser-induced surface and structural modification of silicon (Si) has been investigated under three different environments of vacuum, nitrogen (100 Torr) and ethanol. The interaction of 1000 pulses of KrF (λ ≈ 248 nm, τ ≈ 18 ns, repetition rate ≈ 30 Hz) Excimer laser at two different fluences of 2.8 J/cm{sup 2} and 4 J/cm{sup 2} resulted in formation of various kinds of features such as laser induced periodic surface structures (LIPSS), spikes, columns, cones and cracks. Surface morphology has been observed by Scanning Electron Microscope (SEM). Whereas, structural modification of irradiated targets is explored by Raman spectroscopy. SEM analysis exhibits a non-uniform distribution of micro-scale pillars and spikes at the central ablated regime of silicon irradiated at low laser fluence of 2.8 J/cm{sup 2} under vacuum. Whereas cones, pits, cavities and ripples like features are seen at the boundaries. At higher fluence of 4 J/cm{sup 2}, laser induced periodic structures as well as micro-columns are observed. In the case of ablation in nitrogen environment, melting, splashing, self-organized granular structures and cracks along with redeposition are observed at lower fluence. Such types of small scaled structures in nitrogen are attributed to confinement and shielding effects of nitrogen plasma. Whereas, a crater with multiple ablative layers is formed in the case of ablation at higher fluence. Significantly different surface morphology of Si is observed in the case of ablation in ethanol. It reveals the formation of cavities along with small scale pores and less redeposition. These results reveal that the growth of surface and morphological features of irradiated Si are strongly

  13. Reduced adhesion of macrophages on anodized titanium with select nanotube surface features.

    Science.gov (United States)

    Rajyalakshmi, Amancherla; Ercan, Batur; Balasubramanian, K; Webster, Thomas J

    2011-01-01

    One of the important prerequisites for a successful orthopedic implant apart from being osteoconductive is the elicitation of a favorable immune response that does not lead to the rejection of the implant by the host tissue. Anodization is one of the simplest surface modification processes used to create nanotextured and nanotubular features on metal oxides which has been shown to improve bone formation. Anodization of titanium (Ti) leads to the formation of TiO(2) nanotubes on the surface, and the presence of these nanotubes mimics the natural nanoscale features of bone, which in turn contributes to improved bone cell attachment, migration, and proliferation. However, inflammatory cell responses on anodized Ti remains to be tested. It is hypothesized that surface roughness and surface feature size on anodized Ti can be carefully manipulated to control immune cell (specifically, macrophages) responses. Here, when Ti samples were anodized at 10 V in the presence of 1% hydrofluoric acid (HF) for 1 minute, nanotextured (nonnanotube) surfaces were created. When anodization of Ti samples was carried out with 1% HF for 10 minutes at 15 V, nanotubes with 40-50 nm diameters were formed, whereas at 20 V with 1% HF for 10 minutes, nanotubes with 60-70 nm diameters were formed. In this study, a reduced density of macrophages was observed after 24 hours of culture on nanotextured and nanotubular Ti samples which were anodized at 10, 15, and 20 V, compared with conventional unmodified Ti samples. This in vitro study thus demonstrated a reduced density of macrophages on anodized Ti, thereby providing further evidence of the greater efficacy of anodized Ti for orthopedic applications.

  14. Reduced adhesion of macrophages on anodized titanium with select nanotube surface features

    Directory of Open Access Journals (Sweden)

    Balasubramanian K

    2011-08-01

    Full Text Available Amancherla Rajyalakshmi1, Batur Ercan2,3, K Balasubramanian1, Thomas J Webster2,31Non-Ferrous Materials Technology Development Centre, Hyderabad, India; 2School of Engineering, 3Department of Orthopedics, Brown University, Providence, RI, USAAbstract: One of the important prerequisites for a successful orthopedic implant apart from being osteoconductive is the elicitation of a favorable immune response that does not lead to the rejection of the implant by the host tissue. Anodization is one of the simplest surface modification processes used to create nanotextured and nanotubular features on metal oxides which has been shown to improve bone formation. Anodization of titanium (Ti leads to the formation of TiO2 nanotubes on the surface, and the presence of these nanotubes mimics the natural nanoscale features of bone, which in turn contributes to improved bone cell attachment, migration, and proliferation. However, inflammatory cell responses on anodized Ti remains to be tested. It is hypothesized that surface roughness and surface feature size on anodized Ti can be carefully manipulated to control immune cell (specifically, macrophages responses. Here, when Ti samples were anodized at 10 V in the presence of 1% hydrofluoric acid (HF for 1 minute, nanotextured (nonnanotube surfaces were created. When anodization of Ti samples was carried out with 1% HF for 10 minutes at 15 V, nanotubes with 40–50 nm diameters were formed, whereas at 20 V with 1% HF for 10 minutes, nanotubes with 60–70 nm diameters were formed. In this study, a reduced density of macrophages was observed after 24 hours of culture on nanotextured and nanotubular Ti samples which were anodized at 10, 15, and 20 V, compared with conventional unmodified Ti samples. This in vitro study thus demonstrated a reduced density of macrophages on anodized Ti, thereby providing further evidence of the greater efficacy of anodized Ti for orthopedic applications.Keywords: anodization, titanium

  15. A NEW APPROACH OF DIGITAL BRIDGE SURFACE MODEL GENERATION

    OpenAIRE

    Ju, H.

    2012-01-01

    Bridge areas present difficulties for orthophotos generation and to avoid “collapsed” bridges in the orthoimage, operator assistance is required to create the precise DBM (Digital Bridge Model), which is, subsequently, used for the orthoimage generation. In this paper, a new approach of DBM generation, based on fusing LiDAR (Light Detection And Ranging) data and aerial imagery, is proposed. The no precise exterior orientation of the aerial image is required for the DBM generation. First, a co...

  16. Spectral Analysis of Surface Features of Subaquaeous Pyroclastic Flow Deposits Around Santorini Volcano, Greece

    Science.gov (United States)

    Croff, K. L.; Sigurdsson, H.; Carey, S.; Alexandri, M.; Sakellariou, D.; Nomikou, P.

    2006-12-01

    Multibeam bathymetry mapping and seismic airgun surveys of the submarine region around the Santorini volcanic field in the Hellenic Arc (Greece) have revealed regions of terraced or step-like topography. These features may be related to the transport and deposition of submarine pyroclastic flows from the last major eruption of this volcano (~3600yrs. B.P.). The uppermost sediment sequence identified in seismic records has an average thickness of approximately 29 meters and may represent the pyroclastic flow deposits from this eruption. These terraced or step-like features are mainly located in areas that are approximately five kilometers offshore and at depths in the range of 200 to 800 meters. The seafloor in these areas has slope ratios on the order of 1:20. Profiles of the seafloor topography were sampled from seismic profiles that radiate from the Sanotrini caldera in five regions of interest. Spectral analysis of seafloor topography has been carried out to determine spectral characteristics of these features, including power spectrum, periodicity and amplitude of the waveforms, variance, and roughness of topography. The results are compared to surface features of the subaqueous pyroclastic deposits from the 1883 explosive eruption of Krakatau (Indonesia) and other areas with similar environments, to determine the parameters that are characteristic of this new feature of submarine volcaniclastic deposits.

  17. Topological Properties and Transition Features Generated by a New Hybrid Preferential Model

    Institute of Scientific and Technical Information of China (English)

    FANG Jin-Qing; LIANG Yong

    2005-01-01

    @@ A new hybrid preferential model (HPM) is proposed for generating both scale-free and small world properties.The topological transition features in the HPM from random preferential attachment to deterministic preferential attachment are investigated. It is found that the exponents γ of the power law are very sensitive to the hybrid ratio (d/r) of determination to random attachment, and γincreases as the ratio d/r increases. It is also found that there exists a threshold at d/r = 1/1, beyond which γ increases rapidly and can tend to infinity if there is no random preferential attachment (r = 0), which implies that the power law scaling disappears completely.Moreover, it is also found that when the ratio d/r increases, the average path length L is decreased, while the average clustering coefficient C is increased. Compared to the BA model and random graph, the new HPM has both the smallest L and the biggest C, which is consistent with most real-world growing networks.

  18. Enhancing vapor generation at a liquid-solid interface using micro/nanoscale surface structures fabricated by femtosecond laser surface processing

    Science.gov (United States)

    Anderson, Troy P.; Wilson, Chris; Zuhlke, Craig A.; Kruse, Corey; Gogos, George; Ndao, Sidy; Alexander, Dennis

    2015-03-01

    Femtosecond Laser Surface Processing (FLSP) is a versatile technique for the fabrication of a wide variety of micro/nanostructured surfaces with tailored physical and chemical properties. Through control over processing conditions such as laser fluence, incident pulse count, polarization, and incident angle, the size and density of both micrometer and nanometer-scale surface features can be tailored. Furthermore, the composition and pressure of the environment both during and after laser processing have a substantial impact on the final surface chemistry of the target material. FLSP is therefore a powerful tool for optimizing interfacial phenomena such as wetting, wicking, and phasetransitions associated with a vapor/liquid/solid interface. In the present study, we utilize a series of multiscale FLSPgenerated surfaces to improve the efficiency of vapor generation on a structured surface. Specifically, we demonstrate that FLSP of stainless steel 316 electrode surfaces in an alkaline electrolysis cell results in increased efficiency of the water-splitting reaction used to generate hydrogen. The electrodes are fabricated to be superhydrophilic (the contact angle of a water droplet on the surface is less than 5 degrees). The overpotential of the hydrogen evolution reaction (HER) is measured using a 3-electrode configuration with a structured electrode as the working electrode. The enhancement is attributed to several factors including increased surface area, increased wettability, and the impact of micro/nanostructures on the bubble formation and release. Special emphasis is placed on identifying and isolating the relative impacts of the various contributions.

  19. A Hardware-Implementation-Friendly Pulse-Coupled Neural Network Algorithm for Analog Image-Feature-Generation Circuits

    Science.gov (United States)

    Chen, Jun; Shibata, Tadashi

    2007-04-01

    Pulse-coupled neural networks (PCNNs) are biologically inspired algorithms that have been shown to be highly effective for image feature generation. However, conventional PCNNs are software-oriented algorithms that are too complicated to implement as very-large-scale integration (VLSI) hardware. To employ PCNNs in image-feature-generation VLSIs, a hardware-implementation-friendly PCNN is proposed here. By introducing the concepts of exponentially decaying output and a one-branch dendritic tree, the new PCNN eliminates the large number of convolution operators and floating-point multipliers in conventional PCNNs without compromising its performance at image feature generation. As an analog VLSI implementation of the new PCNN, an image-feature-generation circuit is proposed. By employing floating-gate metal-oxide-semiconductor (MOS) technology, the circuit achieves a full voltage-mode implementation of the PCNN in a compact structure. Inheriting the merits of the PCNN, the circuit is capable of generating rotation-independent and translation-independent features for input patterns, which has been verified by SPICE simulation.

  20. Geologically recent small-scale surface features in Meridiani Planum and Gale Crater, Mars

    Science.gov (United States)

    Horne, David

    2014-05-01

    Enigmatic small scale (run-off may occur occasionally under present conditions in low, near-equatorial latitudes on Mars; short-lived (even for just a few minutes) meltwater emission and flow at the surface could erode gutters before evaporating. The decomposition of buried pockets of methane clathrates, which theoretical considerations suggest might be present and stable even in equatorial regions, could give rise to both methane venting (leveed fissures) and transient surface water (gutters). Another possibility is the decomposition, due to local changes in thermal conditions, of hydrated magnesium sulphates in the bedrock, releasing liquid water. Whatever their explanation, these features hint at previously unrecognized, young martian surface processes which may even be active at the present day; in this context, the apparent downslope extension of a discrete dark dust streak on Burns Cliff (inside Endurance Crater), during Opportunity's approach to that locality, is particularly thought-provoking.

  1. Lipase degradation of plasticized polyvinyl chloride endotracheal tube surfaces to create nanoscale features

    Science.gov (United States)

    Machado, Mary C; Webster, Thomas J

    2017-01-01

    Polyvinyl chloride (PVC) endotracheal tubes (ETTs) nanoetched with a fungal lipase have been shown to reduce bacterial growth and biofilm formation and could be an inexpensive solution to the complex problem of ventilator-associated pneumonia (VAP). Although bacterial growth and colonization on these nanoetched materials have been well characterized, little is known about the mechanism by which the fungal lipase degrades the PVC and, thus, alters its properties to minimize bacteria functions. This study used X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) to better describe the surface chemistry of both unetched and lipase nanoetched PVC ETT. ATR-FTIR analysis of the unetched and treated surfaces showed a similar presence of a plasticizer. This was confirmed by XPS analysis, which showed an increase of carbon and the presence of oxygen on both unetched and nanoetched surfaces. A quantitative comparison of the FTIR spectra revealed significant correlations (Pearson’s correlation, R=0.997 [R2=0.994, Pinfrared peaks due to the degradation of the plasticizer by the fungal lipase. In contrast, results from this study did demonstrate significantly increased nanoscale surface features on the lipase etched compared to non-etched PVC ETTs. This led to a change in surface energetics, which altered ion adsorption to the ETTs. Thus, these results showed that PVC surfaces nanoetched with a 0.1% lipase solution for 48 hours have no significant change on surface chemistry but do significantly increase nanoscale surface roughness and alters ion adsorption, which suggests that the unique properties of these materials, including their previously reported ability to decrease bacterial adhesion and growth, are due to the changes in the degree of the nanoscale roughness, not changes in their surface chemistry. PMID:28352177

  2. Differential surface models for tactile perception of shape and on-line tracking of features

    Science.gov (United States)

    Hemami, H.

    1987-01-01

    Tactile perception of shape involves an on-line controller and a shape perceptor. The purpose of the on-line controller is to maintain gliding or rolling contact with the surface, and collect information, or track specific features of the surface such as edges of a certain sharpness. The shape perceptor uses the information to perceive, estimate the parameters of, or recognize the shape. The differential surface model depends on the information collected and on the a priori information known about the robot and its physical parameters. These differential models are certain functionals that are projections of the dynamics of the robot onto the surface gradient or onto the tangent plane. A number of differential properties may be directly measured from present day tactile sensors. Others may have to be indirectly computed from measurements. Others may constitute design objectives for distributed tactile sensors of the future. A parameterization of the surface leads to linear and nonlinear sequential parameter estimation techniques for identification of the surface. Many interesting compromises between measurement and computation are possible.

  3. In vitro bioactivity of micro metal injection moulded stainless steel with defined surface features

    Directory of Open Access Journals (Sweden)

    C Brose

    2012-05-01

    Full Text Available Micrometre- and nanometre-scale surface structuring with ordered topography features may dramatically enhance orthopaedic implant integration. In this study we utilised a previously optimised micron metal injection moulding (µ-MIM process to produce medical grade stainless steel surfaces bearing micrometre scale, protruding, hemispheres of controlled dimensions and spatial distribution. Additionally, the structured surfaces were characterised by the presence of submicrometre surface roughness resulting from metal grain boundary formation. Following cytocompatibility (cytotoxicity evaluation using 3T3 mouse fibroblast cell line, the effect on primary human cell functionality was assessed focusing on cell attachment, shape and cytoskeleton conformation. In this respect, and by day 7 in culture, significant increase in focal adhesion size was associated with the microstructured surfaces compared to the planar control. The morphological conformation of the seeded cells, as revealed by fluorescence cytoskeleton labelling, also appeared to be guided in the vertical dimension between the hemisphere bodies. Quantitative evaluation of this guidance took place using live cytoplasm fluorescence labelling and image morphometry analysis utilising both, compactness and elongation shape descriptors. Significant increase in cell compactness was associated with the hemisphere arrays indicating collective increase in focused cell attachment to the hemisphere bodies across the entire cell population. Micrometre-scale hemisphere array patterns have therefore influenced cell attachment and conformation. Such influence may potentially aid in enhancing key cellular events such as, for example, neo-osteogenesis on implanted orthopaedic surfaces.

  4. Examining the Impact of Question Surface Features on Students' Answers to Constructed-Response Questions on Photosynthesis

    Science.gov (United States)

    Weston, Michele; Haudek, Kevin C.; Prevost, Luanna; Urban-Lurain, Mark; Merrill, John

    2015-01-01

    One challenge in science education assessment is that students often focus on surface features of questions rather than the underlying scientific principles. We investigated how student written responses to constructed-response questions about photosynthesis vary based on two surface features of the question: the species of plant and the order of…

  5. Exploring microstructure and surface features of Chinese coins using non-invasive approaches

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Ruishi, E-mail: rxie@foxmail.com [Analytical and Testing Center, Southwest University of Science and Technology, Mianyang 621010 (China); Li, Yuanli [Department of Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Guo, Baogang; Hu, Hailong; Jiang, Linhai [Analytical and Testing Center, Southwest University of Science and Technology, Mianyang 621010 (China)

    2015-03-30

    Highlights: • The microstructure and surface features of Chinese coins were systematically explored. • The application of non-invasive techniques enables unambiguous explorations of the component, morphology, microstructure and physical properties of the coins. • This work provides a new insight into exploration of surface properties of precious metal objects, metallic artefacts as well as monuments without causing any damage to them. - Abstract: Despite the apparent significance of Chinese coins, the knowledge about the surface properties of the coins is still largely unknown. To date, most analytical techniques (e.g., cross-section analysis, inductively coupled plasma-mass spectrometry, thermal analysis) require the partial or total destruction of the investigated sample, which is fatal to precious objects (e.g., artefacts and monuments). Herein, we systematically investigate the surface of a series of one yuan Chinese coins to disclose their chemical composition, morphology, and microstructure features using non-invasive techniques. Investigations were performed with scanning electron microscopy, coupled with energy dispersive X-ray spectroscopy, and X-ray diffraction. The application of these approaches enables unambiguous explorations of the component, morphology, microstructure and physical properties of the samples without destroying them. The identification of the coins was achieved in light of the name of issuing authority and floral pattern. The morphology observations of the samples display that these coins possess mostly homogeneous surfaces; hence such a finding allows the formulation of a possible minting technology. Besides, the energy dispersive X-ray spectroscopy has proved of great role in exploring these coins, mainly because of its detectability to easily probe the presence of certain minor elements, which is critical in understanding surface finishing technologies, and production processes. The findings manifest that the coins were made

  6. Surface and morphological features of laser-irradiated silicon under vacuum, nitrogen and ethanol

    Science.gov (United States)

    Hayat, Asma; Bashir, Shazia; Akram, Mahreen; Mahmood, Khaliq; Iqbal, Muhammad Hassan

    2015-12-01

    Laser-induced surface and structural modification of silicon (Si) has been investigated under three different environments of vacuum, nitrogen (100 Torr) and ethanol. The interaction of 1000 pulses of KrF (λ ≈ 248 nm, τ ≈ 18 ns, repetition rate ≈ 30 Hz) Excimer laser at two different fluences of 2.8 J/cm2 and 4 J/cm2 resulted in formation of various kinds of features such as laser induced periodic surface structures (LIPSS), spikes, columns, cones and cracks. Surface morphology has been observed by Scanning Electron Microscope (SEM). Whereas, structural modification of irradiated targets is explored by Raman spectroscopy. SEM analysis exhibits a non-uniform distribution of micro-scale pillars and spikes at the central ablated regime of silicon irradiated at low laser fluence of 2.8 J/cm2 under vacuum. Whereas cones, pits, cavities and ripples like features are seen at the boundaries. At higher fluence of 4 J/cm2, laser induced periodic structures as well as micro-columns are observed. In the case of ablation in nitrogen environment, melting, splashing, self-organized granular structures and cracks along with redeposition are observed at lower fluence. Such types of small scaled structures in nitrogen are attributed to confinement and shielding effects of nitrogen plasma. Whereas, a crater with multiple ablative layers is formed in the case of ablation at higher fluence. Significantly different surface morphology of Si is observed in the case of ablation in ethanol. It reveals the formation of cavities along with small scale pores and less redeposition. These results reveal that the growth of surface and morphological features of irradiated Si are strongly dependent upon the laser fluence as well as environmental conditions. The difference in surface morphology is attributable to cooling, confinement and shielding effects as well as difference in plasma temperature, density and pressure of environmental media that corresponds to different energy deposition

  7. Acoustic Model Training Using Pseudo-Speaker Features Generated by MLLR Transformations for Robust Speaker-Independent Speech Recognition

    OpenAIRE

    Arata Itoh; Sunao Hara; Norihide Kitaoka; Kazuya Takeda

    2012-01-01

    A novel speech feature generation-based acoustic model training method for robust speaker-independent speech recognition is proposed. For decades, speaker adaptation methods have been widely used. All of these adaptation methods need adaptation data. However, our proposed method aims to create speaker-independent acoustic models that cover not only known but also unknown speakers. We achieve this by adopting inverse maximum likelihood linear regression (MLLR) transformation-based feature gene...

  8. Virtual laparoscopy: Initial experience with three-dimensional ultrasonography to characterize hepatic surface features

    Energy Technology Data Exchange (ETDEWEB)

    Sekimoto, Tadashi, E-mail: tad_sekimoto@yahoo.co.jp [Department of Medicine and Clinical Oncology, Chiba University Graduate School of Medicine, 1-8-1, Inohana, Chuo-ku, Chiba, 260-8670 (Japan); Maruyama, Hitoshi, E-mail: maru-cib@umin.ac.jp [Department of Medicine and Clinical Oncology, Chiba University Graduate School of Medicine, 1-8-1, Inohana, Chuo-ku, Chiba, 260-8670 (Japan); Kondo, Takayuki, E-mail: takakondonaika@yahoo.co.jp [Department of Medicine and Clinical Oncology, Chiba University Graduate School of Medicine, 1-8-1, Inohana, Chuo-ku, Chiba, 260-8670 (Japan); Shimada, Taro, E-mail: bobtaro51@yahoo.co.jp [Department of Medicine and Clinical Oncology, Chiba University Graduate School of Medicine, 1-8-1, Inohana, Chuo-ku, Chiba, 260-8670 (Japan); Takahashi, Masanori, E-mail: machat1215@yahoo.co.jp [Department of Medicine and Clinical Oncology, Chiba University Graduate School of Medicine, 1-8-1, Inohana, Chuo-ku, Chiba, 260-8670 (Japan); Yokosuka, Osamu, E-mail: yokosukao@faculty.chiba-u.jp [Department of Medicine and Clinical Oncology, Chiba University Graduate School of Medicine, 1-8-1, Inohana, Chuo-ku, Chiba, 260-8670 (Japan); Otsuka, Masayuki, E-mail: otsuka-m@faculty.chiba-u.jp [Department of General Surgery, Chiba University Graduate School of Medicine, 1-8-1, Inohana, Chuo-ku, Chiba, 260-8670 (Japan); Miyazaki, Masaru, E-mail: masaru@faculty.chiba-u.jp [Department of General Surgery, Chiba University Graduate School of Medicine, 1-8-1, Inohana, Chuo-ku, Chiba, 260-8670 (Japan); Mine, Yoshitaka, E-mail: yoshitaka.mine@toshiba.co.jp [Toshiba Medical Systems Corporation, Ultrasound Systems Division, Ultrasound Systems Development Department, Otawara, Tochigi (Japan)

    2013-06-15

    Objective: To examine the potential utility of 3D-reconstructed sonograms to distinguish cirrhotic from non-cirrhotic livers by demonstrating hepatic surface characteristics. Materials and methods: A preliminary phantom study was performed to examine the potential resolution of 3D images, recognizing surface irregularities as a difference in height. In a prospective clinical study of 31 consecutive patients with ascites (21 cirrhosis, 10 non-cirrhosis), liver volume data were acquired by transabdominal mechanical scanning. The hepatic surface features of cirrhotic and non-cirrhotic patients were compared by 2 independent reviewers. Intra- and inter-operator/reviewer agreements were also examined. Results: The phantom study revealed that 0.4 mm was the minimum recognizable difference in height on the 3D sonograms. The hepatic surface image was successfully visualized in 74% patients (23/31). Success depended on the amount of ascites; visualization was 100% with ascites of 10 mm or more between the hepatic surface and abdominal wall. The images showed irregularity of the hepatic surface in all cirrhotic patients. The surface appearance was confirmed as being very similar in 3 patients who had both 3D sonogram and liver resection for transplantation. The ability to distinguish cirrhotic liver from non-cirrhotic liver improved with the use of combination of 2D- and 3D-imaging versus 2D-imaging alone (sensitivity, p = 0.02; accuracy, p = 0.02) or 3D-imaging alone (sensitivity, p = 0.03). Intra-/inter-operator and inter-reviewer agreement were excellent (κ = 1.0). Conclusion: 3D-based sonographic visualization of the hepatic surface showed high reliability and reproducibility, acting as a virtual laparoscopy method, and the technique has the potential to improve the diagnosis of cirrhosis.

  9. Grain surface features and clay mineralogy of the quaternary sediments from Western Deccan Trap Region, India, and their palaeoclimatic significance

    Directory of Open Access Journals (Sweden)

    Veena U. Joshi

    2011-06-01

    Full Text Available Quartz sand grains obtained from a deeply gullied topography along the banks of two tributaries of River Pravara in Maharashtra (India have been examined with a scanning electron microscope (SEM. Quartz grains have been selected after a heavy mineral separation and micro-photographs of each grain were taken at various angles and magnifications. The sediments reveal features resulting from mechanical grinding as well as from chemical alteration. Conchoidal fractures, cleavage planes, grooves, v-shaped indentations etc. are the mechanical features documented on the grains whereas solution pits of varying sizes and intensity, precipitation surfaces, oriented v-pits, solution crevasses and etching are the features of chemical origin. Several evidences indicate that the samples have undergone digenetic changes. Few grains show the features of intense chemical breakdown. The overall assemblages of the grain surface features suggest that the samples have been subjected to subaqueous transport for a considerable period of time. The minor chemical features such as solution pits or semi circular arcuate steps found in abundance on these grains are due to the dissolution of the sediments in a low energy fluviatile environment. For clay mineralogy, fractions between <2 and <0.2 mm were separated out from the sediments. The clay fractions were then subjected to examination by X-ray diffraction (XRD of oriented K/Ca saturated samples using a Philips Diffractometer and Ni-filtered Cu Ka radiation with the scanning speed of 10 2Ө min -1. The main clay minerals for all the samples are identical and show the presence of hydroxy-interlayered smectites with minor quantities of mica, kaolinite, smectites, quartz and feldspar. The first weathering product of the Deccan Basalt (DB is the dioctahedral smectite. Since the present semi aridic climatic condition of the study area can not transform a smectite to HIS and either smectite to kaolin, it is quite likely that

  10. Generation of surface electrons in femtosecond laser-solid interactions

    Institute of Scientific and Technical Information of China (English)

    XU; Miaohua; LI; Yutong; YUAN; Xiaohui; ZHENG; Zhiyuan; LIANG; Wenxi; YU; Quanzhi; ZHANG; Yi; WANG; Zhaohua; WEI; Zhiyi; ZHANG; Jie

    2006-01-01

    The characteristics of hot electrons produced by p-polarized femtosecond laser-solid interactions are studied. The experimental results show that the outgoing electrons are mainly emitted in three directions: along the target surface, the normal direction and the laser backward direction. The electrons flowing along the target surface are due to the confinement of the electrostatic field and the surface magnetic field, while the electrons in the normal direction due to the resonant absorption.

  11. Surface Rupture and Geotechnical Features of The July 2, 2013 Tanah Gayo Earthquake

    Directory of Open Access Journals (Sweden)

    Mudrik Rahmawan Daryono

    2016-08-01

    Full Text Available An assessment of surface rupture and collateral ground failures can help to evaluate the impact of future earthquakes. This paper presents the results of a field survey conducted to map the surface rupture and geotechnical phenomena associated with the ground shaking during the July 2, 2013 earthquakes in Tanah Gayo Highland. The objectives of this survey are to document and to characterize the surface ruptures as well as to identify types of earthquake-induced ground failures. Results of the survey identified four best sites of possible surface rupture. Two locations are obvious surface ruptures that can be traced on primary topographic feature of the active fault segment from the north to the south, crossing Pantan Terong Hill. The fault segment has a total mapped length of 19 km, with WNW trending zone and a dextral rupture offset. The ground shaking also resulted in landslides and liquefaction in areas underlain by very fine-grained tuffaceous sands. Based on the field survey, it can be concluded that the newly defined active fault segment, the Pantan Terong segment, is likely the segment that ruptured at the July 2, 2013 Tanah Gayo earthquake. Due to the soil types and unstable rocky slopes in the hilly Central Aceh region, large-scale landslides are primary risks during an earthquake event in this region.

  12. Mean shift texture surface detection based on WT and COM feature image selection

    Institute of Scientific and Technical Information of China (English)

    HAN Yan-fang; SHI Peng-fei

    2006-01-01

    Mean shift is a widely used clustering algorithm in image segmentation. However, the segmenting results are not so good as expected when dealing with the texture surface due to the influence of the textures. Therefore, an approach based on wavelet transform (WT), co-occurrence matrix (COM) and mean shift is proposed in this paper. First, WT and COM are employed to extract the optimal resolution approximation of the original image as feature image. Then, mean shift is successfully used to obtain better detection results. Finally, experiments are done to show this approach is effective.

  13. Evaluation of land ownership, lease status, and surface features in five geopressured geothermal prospects

    Energy Technology Data Exchange (ETDEWEB)

    Hackenbracht, W.N.

    1981-05-01

    This study was accomplished for the purpose of gathering information pertaining to land and lease ownership, surface features and use and relevant environmental factors in the Lake Theriot (West and East), Kaplan, Bayou Hebert and Freshwater Bayou geopressured geothermal prospects in Louisiana, and the Blessing geopressured geothermal prospect in Texas. This information and recommendations predicated upon it will then be used to augment engineering and geological data utilized to select geopressured geothermal test well sites within the prospects. The five geopressured geothermal prospects are briefly described and recommendations given.

  14. Role of radiogenic heat generation in surface heat flow formation

    Science.gov (United States)

    Khutorskoi, M. D.; Polyak, B. G.

    2016-03-01

    Heat generation due to decay of long-lived radioactive isotopes is considered in the Earth's crust of the Archean-Proterozoic and Paleozoic provinces of Eurasia and North America. The heat flow that forms in the mantle is calculated as the difference between the heat flow observed at the boundary of the solid Earth and radiogenic heat flow produced in the crust. The heat regime in regions with anomalously high radiogenic heat generation is discussed. The relationship between various heat flow components in the Precambrian and Phanerozoic provinces has been comparatively analyzed, and the role of erosion of the surfaceheat- generating layer has been estimated.

  15. Surface structure enhanced second harmonic generation in organic nanofibers

    DEFF Research Database (Denmark)

    Fiutowski, Jacek; Maibohm, Christian; Kostiucenko, Oksana;

    Second-harmonic generation upon femto-second laser irradiation of nonlinearly optically active nanofibers grown from nonsymmetrically functionalized para-quarterphenylene (CNHP4) molecules is investigated. Following growth on mica templates, the nanofibers have been transferred onto lithography-d......-defined regular arrays of gold square nanostructures. These nanostructure arrays induce local field enhancement, which significantly lowers the threshold for second harmonic generation in the nanofibers.......Second-harmonic generation upon femto-second laser irradiation of nonlinearly optically active nanofibers grown from nonsymmetrically functionalized para-quarterphenylene (CNHP4) molecules is investigated. Following growth on mica templates, the nanofibers have been transferred onto lithography...

  16. Feature-preserving surface mesh smoothing via suboptimal Delaunay triangulation ☆

    Science.gov (United States)

    Gao, Zhanheng; Yu, Zeyun; Holst, Michael

    2012-01-01

    A method of triangular surface mesh smoothing is presented to improve angle quality by extending the original optimal Delaunay triangulation (ODT) to surface meshes. The mesh quality is improved by solving a quadratic optimization problem that minimizes the approximated interpolation error between a parabolic function and its piecewise linear interpolation defined on the mesh. A suboptimal problem is derived to guarantee a unique, analytic solution that is significantly faster with little loss in accuracy as compared to the optimal one. In addition to the quality-improving capability, the proposed method has been adapted to remove noise while faithfully preserving sharp features such as edges and corners of a mesh. Numerous experiments are included to demonstrate the performance of the method. PMID:23580890

  17. Biomaterial design for specific cellular interactions: Role of surface functionalization and geometric features

    Science.gov (United States)

    Kolhar, Poornima

    The areas of drug delivery and tissue engineering have experienced extraordinary growth in recent years with the application of engineering principles and their potential to support and improve the field of medicine. The tremendous progress in nanotechnology and biotechnology has lead to this explosion of research and development in biomedical applications. Biomaterials can now be engineered at a nanoscale and their specific interactions with the biological tissues can be modulated. Various design parameters are being established and researched for design of drug-delivery carriers and scaffolds to be implanted into humans. Nanoparticles made from versatile biomaterial can deliver both small-molecule drugs and various classes of bio-macromolecules, such as proteins and oligonucleotides. Similarly in the field of tissue engineering, current approaches emphasize nanoscale control of cell behavior by mimicking the natural extracellular matrix (ECM) unlike, traditional scaffolds. Drug delivery and tissue engineering are closely connected fields and both of these applications require materials with exceptional physical, chemical, biological, and biomechanical properties to provide superior therapy. In the current study the surface functionalization and the geometric features of the biomaterials has been explored. In particular, a synthetic surface for culture of human embryonic stem cells has been developed, demonstrating the importance of surface functionalization in maintaining the pluripotency of hESCs. In the second study, the geometric features of the drug delivery carriers are investigated and the polymeric nanoneedles mediated cellular permeabilization and direct cytoplasmic delivery is reported. In the third study, the combined effect of surface functionalization and geometric modification of carriers for vascular targeting is enunciated. These studies illustrate how the biomaterials can be designed to achieve various cellular behaviors and control the

  18. Generation of 1D interference patterns of Bloch surface waves

    Science.gov (United States)

    Kadomina, E. A.; Bezus, E. A.; Doskolovich, L. L.

    2016-09-01

    Interference patterns of Bloch surface waves with a period that is significantly less than the wavelength of incident radiation are formed using dielectric diffraction gratings located on the surface of photonic crystal. The simulation based on electromagnetic diffraction theory is used to demonstrate the possibility of high-quality interference patterns due to resonant enhancement of higher evanescent diffraction orders related to the excitation of the Bloch surface waves. The contrast of the interference patterns is close to unity, and the period is less than the period of the diffraction structure by an order of magnitude.

  19. All-Optical Generation of Surface Plasmons in Graphene

    CERN Document Server

    Constant, Thomas J; Chang, Darrick E; Hendry, Euan

    2015-01-01

    Here we present an all-optical plasmon coupling scheme, utilising the intrinsic nonlinear optical response of graphene. We demonstrate coupling of free-space, visible light pulses to the surface plasmons in a planar, un-patterned graphene sheet by using nonlinear wave mixing to match both the wavevector and energy of the surface wave. By carefully controlling the phase-matching conditions, we show that one can excite surface plasmons with a defined wavevector and direction across a large frequency range, with an estimated photon efficiency in our experiments approaching $10^{-5}$.

  20. Surface Generated Acoustic Wave Biosensors for the Detection of Pathogens: A Review

    Directory of Open Access Journals (Sweden)

    Antonio Arnau-Vives

    2009-07-01

    Full Text Available This review presents a deep insight into the Surface Generated Acoustic Wave (SGAW technology for biosensing applications, based on more than 40 years of technological and scientific developments. In the last 20 years, SGAWs have been attracting the attention of the biochemical scientific community, due to the fact that some of these devices - Shear Horizontal Surface Acoustic Wave (SH-SAW, Surface Transverse Wave (STW, Love Wave (LW, Flexural Plate Wave (FPW, Shear Horizontal Acoustic Plate Mode (SH-APM and Layered Guided Acoustic Plate Mode (LG-APM - have demonstrated a high sensitivity in the detection of biorelevant molecules in liquid media. In addition, complementary efforts to improve the sensing films have been done during these years. All these developments have been made with the aim of achieving, in a future, a highly sensitive, low cost, small size, multi-channel, portable, reliable and commercially established SGAW biosensor. A setup with these features could significantly contribute to future developments in the health, food and environmental industries. The second purpose of this work is to describe the state-of-the-art of SGAW biosensors for the detection of pathogens, being this topic an issue of extremely importance for the human health. Finally, the review discuses the commercial availability, trends and future challenges of the SGAW biosensors for such applications.

  1. Effect of thin film on the generation of vorticity by surface waves

    CERN Document Server

    Parfenyev, V M; Lebedev, V V

    2016-01-01

    Recently a theoretical scheme explaining the vorticity generation by surface waves in liquids was developed [S. Filatov et al., Phys. Rev. Lett. 116, 054501 (2016)]. Here we study how a thin (monomolecular) film presented at the surface of liquid affects the generated vorticity. We demonstrate that the vorticity becomes parametrically larger than for the case with a clean surface and now it depends on viscosity of the liquid. We also discuss the motion of particles passively advected by the generated surface flow. The results can be used in different applications: from the analysis of pollutants' diffusion on the ocean surface till the reconstruction of vorticity based on the particle image velocimetry (PIV) measurements.

  2. Decoding subtle forearm flexions using fractal features of surface electromyogram from single and multiple sensors

    Directory of Open Access Journals (Sweden)

    Kumar Dinesh

    2010-10-01

    Full Text Available Abstract Background Identifying finger and wrist flexion based actions using a single channel surface electromyogram (sEMG can lead to a number of applications such as sEMG based controllers for near elbow amputees, human computer interface (HCI devices for elderly and for defence personnel. These are currently infeasible because classification of sEMG is unreliable when the level of muscle contraction is low and there are multiple active muscles. The presence of noise and cross-talk from closely located and simultaneously active muscles is exaggerated when muscles are weakly active such as during sustained wrist and finger flexion. This paper reports the use of fractal properties of sEMG to reliably identify individual wrist and finger flexion, overcoming the earlier shortcomings. Methods SEMG signal was recorded when the participant maintained pre-specified wrist and finger flexion movements for a period of time. Various established sEMG signal parameters such as root mean square (RMS, Mean absolute value (MAV, Variance (VAR and Waveform length (WL and the proposed fractal features: fractal dimension (FD and maximum fractal length (MFL were computed. Multi-variant analysis of variance (MANOVA was conducted to determine the p value, indicative of the significance of the relationships between each of these parameters with the wrist and finger flexions. Classification accuracy was also computed using the trained artificial neural network (ANN classifier to decode the desired subtle movements. Results The results indicate that the p value for the proposed feature set consisting of FD and MFL of single channel sEMG was 0.0001 while that of various combinations of the five established features ranged between 0.009 - 0.0172. From the accuracy of classification by the ANN, the average accuracy in identifying the wrist and finger flexions using the proposed feature set of single channel sEMG was 90%, while the average accuracy when using a combination

  3. Mining consumer reviews to generate ratings of different product attributes while producing feature-based review-summary

    Science.gov (United States)

    Kangale, Akshay; Krishna Kumar, S.; Arshad Naeem, Mohd; Williams, Mark; Tiwari, M. K.

    2016-10-01

    With the massive growth of the internet, product reviews increasingly serve as an important source of information for customers to make choices online. Customers depend on these reviews to understand users' experience, and manufacturers rely on this user-generated content to capture user sentiments about their product. Therefore, it is in the best interest of both customers and manufacturers to have a portal where they can read a complete comprehensive summary of these reviews in minimum time. With this in mind, we arrived at our first objective which is to generate a feature-based review-summary. Our second objective is to develop a predictive model to know the next week's product sales based on numerical review ratings and textual features embedded in the reviews. When it comes to product features, every user has different priorities for different features. To capture this aspect of decision-making, we have designed a new mechanism to generate a numerical rating for every feature of the product individually. The data have been collected from a well-known commercial website for two different products. The validation of the model is carried out using a crowd-sourcing technique.

  4. Comparison of unsteady pressure fields on turrets with different surface features using pressure-sensitive paint

    Science.gov (United States)

    Gordeyev, Stanislav; De Lucca, Nicholas; Jumper, Eric J.; Hird, Kyle; Juliano, Thomas J.; Gregory, James W.; Thordahl, James; Wittich, Donald J.

    2014-01-01

    Spatially temporally resolved unsteady pressure fields on a surface of a hemisphere-on-cylinder turret with either a flat or a conformal window with realistic features such as gaps and "smile" cutouts were characterized using fast-response pressure-sensitive paint at M = 0.33 for several window viewing angles. Various statistical properties of pressure fields were computed, and geometry effects on the unsteady pressure fields were analyzed and discussed. Proper orthogonal decomposition was also used to extract dominant pressure modes and corresponding temporal coefficients and to analyze and compare instantaneous pressure structures for different turret geometric features and the window viewing angles. An unsteady separation off the turret and a recirculation region downstream of the turret were identified as dominant sources of the unsteady pressure. It was found that while all geometric features affected the unsteady pressure field, the "smiles," positioned spanwise-symmetrically on both sides of the turret, were the leading cause of these changes, followed by the looking forward flat window. The gaps, the side- and the back-looking flat window introduced only small local changes.

  5. Automatic generation of endocardial surface meshes with 1-to-1 correspondence from cine-MR images

    Science.gov (United States)

    Su, Yi; Teo, S.-K.; Lim, C. W.; Zhong, L.; Tan, R. S.

    2015-03-01

    In this work, we develop an automatic method to generate a set of 4D 1-to-1 corresponding surface meshes of the left ventricle (LV) endocardial surface which are motion registered over the whole cardiac cycle. These 4D meshes have 1- to-1 point correspondence over the entire set, and is suitable for advanced computational processing, such as shape analysis, motion analysis and finite element modelling. The inputs to the method are the set of 3D LV endocardial surface meshes of the different frames/phases of the cardiac cycle. Each of these meshes is reconstructed independently from border-delineated MR images and they have no correspondence in terms of number of vertices/points and mesh connectivity. To generate point correspondence, the first frame of the LV mesh model is used as a template to be matched to the shape of the meshes in the subsequent phases. There are two stages in the mesh correspondence process: (1) a coarse matching phase, and (2) a fine matching phase. In the coarse matching phase, an initial rough matching between the template and the target is achieved using a radial basis function (RBF) morphing process. The feature points on the template and target meshes are automatically identified using a 16-segment nomenclature of the LV. In the fine matching phase, a progressive mesh projection process is used to conform the rough estimate to fit the exact shape of the target. In addition, an optimization-based smoothing process is used to achieve superior mesh quality and continuous point motion.

  6. Stream/bounce event perception reveals a temporal limit of motion correspondence based on surface feature over space and time.

    Science.gov (United States)

    Kawachi, Yousuke; Kawabe, Takahiro; Gyoba, Jiro

    2011-01-01

    We examined how stream/bounce event perception is affected by motion correspondence based on the surface features of moving objects passing behind an occlusion. In the stream/bounce display two identical objects moving across each other in a two-dimensional display can be perceived as either streaming through or bouncing off each other at coincidence. Here, surface features such as colour (Experiments 1 and 2) or luminance (Experiment 3) were switched between the two objects at coincidence. The moment of coincidence was invisible to observers due to an occluder. Additionally, the presentation of the moving objects was manipulated in duration after the feature switch at coincidence. The results revealed that a postcoincidence duration of approximately 200 ms was required for the visual system to stabilize judgments of stream/bounce events by determining motion correspondence between the objects across the occlusion on the basis of the surface feature. The critical duration was similar across motion speeds of objects and types of surface features. Moreover, controls (Experiments 4a-4c) showed that cognitive bias based on feature (colour/luminance) congruency across the occlusion could not fully account for the effects of surface features on the stream/bounce judgments. We discuss the roles of motion correspondence, visual feature processing, and attentive tracking in the stream/bounce judgments.

  7. Stream/Bounce Event Perception Reveals a Temporal Limit of Motion Correspondence Based on Surface Feature over Space and Time

    Directory of Open Access Journals (Sweden)

    Yousuke Kawachi

    2011-06-01

    Full Text Available We examined how stream/bounce event perception is affected by motion correspondence based on the surface features of moving objects passing behind an occlusion. In the stream/bounce display two identical objects moving across each other in a two-dimensional display can be perceived as either streaming through or bouncing off each other at coincidence. Here, surface features such as colour (Experiments 1 and 2 or luminance (Experiment 3 were switched between the two objects at coincidence. The moment of coincidence was invisible to observers due to an occluder. Additionally, the presentation of the moving objects was manipulated in duration after the feature switch at coincidence. The results revealed that a postcoincidence duration of approximately 200 ms was required for the visual system to stabilize judgments of stream/bounce events by determining motion correspondence between the objects across the occlusion on the basis of the surface feature. The critical duration was similar across motion speeds of objects and types of surface features. Moreover, controls (Experiments 4a–4c showed that cognitive bias based on feature (colour/luminance congruency across the occlusion could not fully account for the effects of surface features on the stream/bounce judgments. We discuss the roles of motion correspondence, visual feature processing, and attentive tracking in the stream/bounce judgments.

  8. Evolutionary dynamics of selfish DNA generates pseudo-linguistic features of genomes

    OpenAIRE

    Michael Sheinman; Anna Ramisch; Florian Massip; Arndt, Peter F.

    2016-01-01

    Since the sequencing of large genomes, many statistical features of their sequences have been found. One intriguing feature is that certain subsequences are much more abundant than others. In fact, abundances of subsequences of a given length are distributed with a scale-free power-law tail, resembling properties of human texts, such as the Zipf's law. Despite recent efforts, the understanding of this phenomenon is still lacking. Here we find that selfish DNA elements, such as those belonging...

  9. Mining for diagnostic information in body surface potential maps: A comparison of feature selection techniques

    Directory of Open Access Journals (Sweden)

    McCullagh Paul J

    2005-09-01

    Full Text Available Abstract Background In body surface potential mapping, increased spatial sampling is used to allow more accurate detection of a cardiac abnormality. Although diagnostically superior to more conventional electrocardiographic techniques, the perceived complexity of the Body Surface Potential Map (BSPM acquisition process has prohibited its acceptance in clinical practice. For this reason there is an interest in striking a compromise between the minimum number of electrocardiographic recording sites required to sample the maximum electrocardiographic information. Methods In the current study, several techniques widely used in the domains of data mining and knowledge discovery have been employed to mine for diagnostic information in 192 lead BSPMs. In particular, the Single Variable Classifier (SVC based filter and Sequential Forward Selection (SFS based wrapper approaches to feature selection have been implemented and evaluated. Using a set of recordings from 116 subjects, the diagnostic ability of subsets of 3, 6, 9, 12, 24 and 32 electrocardiographic recording sites have been evaluated based on their ability to correctly asses the presence or absence of Myocardial Infarction (MI. Results It was observed that the wrapper approach, using sequential forward selection and a 5 nearest neighbour classifier, was capable of choosing a set of 24 recording sites that could correctly classify 82.8% of BSPMs. Although the filter method performed slightly less favourably, the performance was comparable with a classification accuracy of 79.3%. In addition, experiments were conducted to show how (a features chosen using the wrapper approach were specific to the classifier used in the selection model, and (b lead subsets chosen were not necessarily unique. Conclusion It was concluded that both the filter and wrapper approaches adopted were suitable for guiding the choice of recording sites useful for determining the presence of MI. It should be noted however

  10. Features of the type Ⅲ-like source rock and its generated natural gas

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The mother matter of Ordovician source are mainly sapropelic and generate oil in mature stage, since the high plants did not appear in Ordovician period, which is well known by internal and external scholars. Now we find a kind of Orodovician source rock generating mainly light oil and gas in mature stage during appraising source rocks in the Tarim Basin. The organic matters of this source rock are chiefly constructed by benthic brown algae in organisms (showing as macro algae), and are similar to humic source in hydrocarbon generation. The natural gas generated by this kind of source matters is obviously different from the sapropelic gas.

  11. Surface structure enhanced second harmonic generation in organic nanofibers

    DEFF Research Database (Denmark)

    Fiutowski, Jacek; Maibohm, Christian; Kostiucenko, Oksana;

    Second-harmonic generation upon femto-second laser irradiation of nonlinearly optically active nanofibers grown from nonsymmetrically functionalized para-quarterphenylene (CNHP4) molecules is investigated. Following growth on mica templates, the nanofibers have been transferred onto lithography-d...

  12. Outstanding Antibiofilm Features of Quanta-CuO Film on Glass Surface.

    Science.gov (United States)

    Tripathy, Nirmalya; Ahmad, Rafiq; Bang, Seung Hyuck; Khang, Gilson; Min, Jiho; Hahn, Yoon-Bong

    2016-06-22

    Intelligently designed surface nanoarchitecture provides defined control over the behavior of cells and biomolecules at the solid-liquid interface. In this study, CuO quantum dots (quanta-CuO; ∼3-5 nm) were synthesized by a simple, low-temperature solution process and further formulated as paint to construct quanta-CuO thin film on glass. Surface morphological characterizations of the as-coated glass surface reveal a uniform film thickness (∼120 ± 10 nm) with homogeneous distribution of quanta-CuO. The antibiofilm assay showed a very high contact bacteria-killing capacity of as-coated quanta-CuO glass surfaces toward Staphylococcus aureus and Escherichia coli. This efficient antibacterial/antibiofilm activity was ascribed to the intracellular reactive oxygen species (ROS) generated by the quanta-CuO attached to the bacterial cells, which leads to an oxidative assault and finally results in bacterial cell death. Although there is a significant debate regarding the CuO nanostructure's antibacterial mode of action, we propose both contact killing and/or copper ion release killing mechanisms for the antibiofilm activity of quanta-CuO paint. Moreover, synergism of quanta-CuO with conventional antibiotics was also found to further enhance the antibacterial efficacy of commonly used antibiotics. Collectively, this state-of-the-art design of quanta-CuO coated glass can be envisioned as promising candidates for various biomedical and environmental device coatings.

  13. Comparison of Three Methods for Generating Superhydrophobic, Superoleophobic Nylon Nonwoven Surfaces (Postprint)

    Science.gov (United States)

    2011-04-01

    AFRL-RX-TY-TP-2010-0076 COMPARISON OF THREE METHODS FOR GENERATING SUPERHYDROPHOBIC, SUPEROLEOPHOBIC NYLON NONWOVEN SURFACES Rahul Saraf...Generating Superhydrophobic, Superoleophobic Nylon Nonwoven Surfaces (POSTPRINT) FA8650-07-1-5916 0602102F GOVT L0 QL102006 ^Saraf, Rahul,; ^Lee, Hoon...three different techniques to achieve superhydrophobicity and superoleophobicity using hydroentangled nylon nonwoven fabric: pulsed plasma polymerization

  14. Surface plasmon polariton excitation by second harmonic generation in single organic nanofibers

    DEFF Research Database (Denmark)

    Simesen, Paw; Søndergaard, Thomas; Skovsen, Esben

    2015-01-01

    Coherent local excitation of surface plasmon polaritons (SPPs) by second-harmonic generation (SHG) in individual aligned crystalline organic functionalized para-phenylene nanofibers deposited on a thin silver film is demonstrated. The SH-SPP generation is considered theoretically and investigated...... to the silver film surface....

  15. Feature extraction and classifcation in surface grading application using multivariate statistical projection models

    Science.gov (United States)

    Prats-Montalbán, José M.; López, Fernando; Valiente, José M.; Ferrer, Alberto

    2007-01-01

    In this paper we present an innovative way to simultaneously perform feature extraction and classification for the quality control issue of surface grading by applying two well known multivariate statistical projection tools (SIMCA and PLS-DA). These tools have been applied to compress the color texture data describing the visual appearance of surfaces (soft color texture descriptors) and to directly perform classification using statistics and predictions computed from the extracted projection models. Experiments have been carried out using an extensive image database of ceramic tiles (VxC TSG). This image database is comprised of 14 different models, 42 surface classes and 960 pieces. A factorial experimental design has been carried out to evaluate all the combinations of several factors affecting the accuracy rate. Factors include tile model, color representation scheme (CIE Lab, CIE Luv and RGB) and compression/classification approach (SIMCA and PLS-DA). In addition, a logistic regression model is fitted from the experiments to compute accuracy estimates and study the factors effect. The results show that PLS-DA performs better than SIMCA, achieving a mean accuracy rate of 98.95%. These results outperform those obtained in a previous work where the soft color texture descriptors in combination with the CIE Lab color space and the k-NN classi.er achieved a 97.36% of accuracy.

  16. Features of deformation of metal body surfaces under impact of a water jet

    Science.gov (United States)

    Aganin, A. A.; Khismatullina, N. A.

    2016-01-01

    The paper presents a mathematical model and computational results on dynamics of a perfect elastic-plastic body under the load arising during impact of a high-velocity liquid jet with the hemispherical end. The body is simulated by the isotropic linearly-elastic semi-space, its plastic state is described by the von Mises condition. The dependence of features of the body surface deformation on the body material is studied. The problem is considered in the axisymmetric statement. The axis of symmetry is that of the jet. The loaded domain is a circle with its radius rapidly growing from zero to the jet radius. The pressure in the loaded domain is non-uniform both in time and space. Three metal alloys (aluminium, copper-nickel and steel) are considered as the body material. The loading of the body surface in all the cases corresponds to the impact of a water jet with the radius 100 pm and the velocity 300 m/s. It has been shown that under such impact a nanometer pit arises on the body surface at the center of the domain of the jet action. The profile of the pit and its maximal depth depend on the body material.

  17. Feature, design intention and constraint preservation for direct modeling of 3D freeform surfaces

    Science.gov (United States)

    Fu, Luoting; Kara, Levent Burak; Shimada, Kenji

    2012-06-01

    Direct modeling has recently emerged as a suitable approach for 3D free-form shape modeling in industrial design. It has several advantages over the conventional, parametric modeling techniques, including natural user interactions, as well as the underlying, automatic feature-preserving shape deformation algorithms. However, current direct modeling packages still lack several capabilities critical for product design, such as managing aesthetic design intentions, and enforcing dimensional, geometric constraints. In this paper, we describe a novel 3D surface editing system capable of jointly accommodating aesthetic design intentions expressed in the form of surface painting and color-coded annotations, as well as engineering constraints expressed as dimensions. The proposed system is built upon differential coordinates and constrained least squares, and is intended for conceptual design that involves frequent shape tuning and explorations. We also provide an extensive review of the state-of-the-art direct modeling approaches for 3D mesh-based, freeform surfaces, with an emphasis on the two broad categories of shape deformation algorithms developed in the relevant field of geometric modeling. [Figure not available: see fulltext.

  18. Oxide cathode mechanisms: Electronic and structural features of oxide cathode surfaces

    Science.gov (United States)

    Cunningham, J.; Nunan, J.

    1985-01-01

    This report describes studies made upon systems selected for their ability to model various important features of oxide cathodes and the mechanisms which enable them to function as efficient thermionic emitters at moderate temperatures. An account is given of experiments which aimed to simulate conditions upon the surfaces of polycrystalline samples of alkaline earth oxides (e.g., SrO and BaO/SrO or MgO and BaO/MgO) at various stages of their preparation in similiar fashion to that used in the thermal activation of oxide cathodes. Accounts are given of experiments which examined the interaction between the gases O2, N2O, H2 or Ch4 and appropriately preactivated surface of pure and mixed alkaline earth oxide samples. Accounts are given of experiments involving the controlled deposition in UHV conditions of zero-valent Ba ad-atoms-in amounts ranging from submonolayer to multilayer coverage - upon layers of SrO or BaO previously prepared in UHV conditions by evaporation of the corresponding metal and its subsequent oxidation. UPS spectra have been undertaken in order to examine surfaces of samples prepared by evaporation of barium metal or strontium metal and to study effects upon the UPS spectra by exposures to the gases N20, O2 and CH4.

  19. Study on End Milling Generation Surface Model and Simulation in View of Main Axle s Tolerance

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In accordance with the relative movement between end-milling cutter and workpiece surface, a theoretical generation model for milled surface was established with the movement error of principal axle considered. Then the milled surfaces under various cutting condition were simulated, the results of which showed that end milled surfaces were of "vaulted profile", heights of surface irregularty at various points to be different with maximum value in the middle and smaller at both sides, the difference were ...

  20. Surface Features Parameterization and Equivalent Roughness Height Estimation of a Real Subglacial Conduit in the Arctic

    Science.gov (United States)

    Chen, Y.; Liu, X.; Manko ff, K. D.; Gulley, J. D.

    2016-12-01

    The surfaces of subglacial conduits are very complex, coupling multi-scale roughness, large sinuosity, and cross-sectional variations together. Those features significantly affect the friction law and drainage efficiency inside the conduit by altering velocity and pressure distributions, thus posing considerable influences on the dynamic development of the conduit. Parameterizing the above surface features is a first step towards understanding their hydraulic influences. A Matlab package is developed to extract the roughness field, the conduit centerline, and associated area and curvature data from the conduit surface, acquired from 3D scanning. By using those data, the characteristic vertical and horizontal roughness scales are then estimated based on the structure functions. The centerline sinuosities, defined through three concepts, i.e., the traditional definition of a fluvial river, entropy-based sinuosity, and curvature-based sinuosity, are also calculated and compared. The cross-sectional area and equivalent circular diameter along the centerline are also calculated. Among those features, the roughness is especially important due to its pivotal role in determining the wall friction, and thus an estimation of the equivalent roughness height is of great importance. To achieve such a goal, the original conduit is firstly simplified into a straight smooth pipe with the same volume and centerline length, and the roughness field obtained above is then reconstructed into the simplified pipe. An OpenFOAM-based Large-eddy-simulation (LES) is then performed based on the reconstructed pipe. Considering that the Reynolds number is of the order 106, and the relative roughness is larger than 5% for 60% of the conduit, we test the validity of the resistance law for completely rough pipe. The friction factor is calculated based on the pressure drop and mean velocity in the simulation. Working together, the equivalent roughness height can be calculated. However, whether the

  1. Example-Based Optimization of Surface-Generation Tables

    CERN Document Server

    Samuelsson, C

    1996-01-01

    A method is given that "inverts" a logic grammar and displays it from the point of view of the logical form, rather than from that of the word string. LR-compiling techniques are used to allow a recursive-descent generation algorithm to perform "functor merging" much in the same way as an LR parser performs prefix merging. This is an improvement on the semantic-head-driven generator that results in a much smaller search space. The amount of semantic lookahead can be varied, and appropriate tradeoff points between table size and resulting nondeterminism can be found automatically. This can be done by removing all spurious nondeterminism for input sufficiently close to the examples of a training corpus, and large portions of it for other input, while preserving completeness.

  2. Proposal for a self-excited electrically driven surface plasmon polariton generator

    Science.gov (United States)

    Bordo, V. G.

    2017-01-01

    We propose a generator of surface plasmon polaritons (SPPs) which, unlike spasers or plasmon lasers, does not require stimulated emission in the system. Its principle of operation is based on a positive feedback which an ensemble of classical oscillating dipoles experiences from a reflective surface located in its near field. The generator design includes a nanocavity between two metal surfaces which contains metal nanoparticles in its interior. The whole structure is placed onto a prism surface that allows one to detect the generated SPPs in the Kretschmann configuration. The generation process is driven by a moderate DC voltage applied between the metal covers of the cavity. Both the generation criterion and the steady-state operation of the generator are investigated.

  3. Nano surface generation of grinding process using carbon nano tubes

    Indian Academy of Sciences (India)

    S Prabhu; B K Vinayagam

    2010-12-01

    Nano surface finish has become an important parameter in the semiconductor, optical, electrical and mechanical industries. The materials used in these industries are classified as difficult to machine materials such as ceramics, glasses and silicon wafers. Machining of these materials up to nano accuracy is a great challenge in the manufacturing industry. Finishing of micro components such as micro-moulds, micro-lenses and micro-holes need different processing techniques. Conventional finishing methods used so far become almost impossible or cumbersome. In this paper, a nano material especially multi wall carbon nano tube is used in the machining process like grinding to improve the surface characteristics from micro to nano level.

  4. Generating accurate dipole moment surfaces using modified Shepard interpolation.

    Science.gov (United States)

    Morris, Michael; Jordan, Meredith J T

    2014-05-28

    We outline an approach for building molecular dipole moment surfaces using modified Shepard interpolation. Our approach is highly automated, requires minimal parameterization, and is iteratively improvable. Using the water molecule as a test case, we investigate how different aspects of the interpolation scheme affect the rate of convergence of calculated IR spectral line intensities. It is found that the interpolation scheme is sensitive to coordinate singularities present at linear geometries. Due to the generally monotonic nature of the dipole moment surface, the one-part weight function is found to be more effective than the more complicated two-part variant, with first-order interpolation also giving better-than-expected results. Almost all sensible schemes for choosing interpolation reference data points are found to exhibit acceptable convergence behavior.

  5. Yeast mating for combinatorial Fab library generation and surface display

    Energy Technology Data Exchange (ETDEWEB)

    Feldhaus, Jane M.; Lou, Jianlong; Coleman, James R.; Siegel, Robert W.; Marks, James D.; Feldhaus, Michael

    2004-04-23

    Yeast display of antibody fragments has proven to be an efficient and productive means for directed evolution of single chain Fv (scFv) antibodies for increased affinity and thermal stability, and more recently for the display and screening of a non-immune library. In this paper, we describe an elegant and simple method for constructing large combinatorial Fab libraries for display on the surface of Saccharomyces cerevisiae, from modestly sized, and easily constructed, heavy and light chain libraries. To this end, we have constructed a set of yeast strains and a two vector system for heavy chain and light chain surface display of Fab fragments with free native amino termini. Through yeast mating of the haploid libraries, a very large heterodimeric immune Fab library was displayed on the diploids and high affinity antigen specific Fabs were isolated from the library.

  6. Surface area-dependent second harmonic generation from silver nanorods.

    Science.gov (United States)

    Ngo, Hoang Minh; Luong, Thanh Tuyen; Ledoux-Rak, Isabelle

    2016-08-17

    The nonlinear optical (NLO) properties of metallic nanoparticles strongly depend on their size and shape. Metallic gold nanorods have already been widely investigated, but other noble metals could also be used for nanorod fabrication towards applications in photonics. Here we report on the synthesis and NLO characterization of silver nanorods (AgNRs) with controllable localized surface plasmon resonance. We have implemented an original, one-step and seedless synthesis method, based on a spontaneous particle growth technique in the presence of polyvinylpyrrolidone (PVP) as a capping agent. Colloidal solutions of AgNRs with various aspect ratios (5.0; 6.3; 7.5; 8.2 and 9.7) have been obtained and characterized using Harmonic light scattering (HLS) at 1064 nm, in order to investigate their quadratic NLO properties. From HLS experiments, we demonstrate that hyperpolarizability (β) values of AgNRs display a strong dependence on their surface area.

  7. Free Surface Influence on Low Head Hydro Power Generation

    Science.gov (United States)

    Pelz, Peter F.; Froehlich, Thibaud

    2016-11-01

    The free surface influence on the power extraction of turbines in open-channel flow is analyzed under use of continuity, momentum and energy equations. The approach differs of previous models by avoiding two drawbacks: the exceeding of the available power with the Betz definition and the inaccurate assumption of an undisturbed approaching flow. The result is an energetic optimization focusing on the energy dissipation due to wake and shock losses downstream of the turbine.

  8. Generation of long subharmonic internal waves by surface waves

    Science.gov (United States)

    Tahvildari, Navid; Kaihatu, James M.; Saric, William S.

    2016-10-01

    A new set of Boussinesq equations is derived to study the nonlinear interactions between long waves in a two-layer fluid. The fluid layers are assumed to be homogeneous, inviscid, incompressible, and immiscible. Based on the Boussinesq equations, an analytical model is developed using a second-order perturbation theory and applied to examine the transient evolution of a resonant triad composed of a surface wave and two oblique subharmonic internal waves. Wave damping due to weak viscosity in both layers is considered. The Boussinesq equations and the analytical model are verified. In contrast to previous studies which focus on short internal waves, we examine long waves and investigate some previously unexplored characteristics of this class of triad interaction. In viscous fluids, surface wave amplitudes must be larger than a threshold to overcome viscous damping and trigger internal waves. The dependency of this critical amplitude as well as the growth and damping rates of internal waves on important parameters in a two-fluid system, namely the directional angle of the internal waves, depth, density, and viscosity ratio of the fluid layers, and surface wave amplitude and frequency is investigated.

  9. Dust generation at interaction of plasma jet with surfaces

    Science.gov (United States)

    Ticos, Catalin; Toader, Dorina; Banu, Nicoleta; Scurtu, Adrian; Oane, Mihai

    2013-10-01

    Coatings of W and C with widths of a few microns will be exposed to plasma jet for studying the erosion of the surface and detachment of micron size dust particles. A coaxial plasma gun has been built inside a vacuum chamber for producing supersonic plasma jets. Its design is based on a 50 kJ coaxial plasma gun which has been successfully used for accelerating hypervelocity dust. Initial shots were carried out for a capacitor bank with C = 12 μF and charged up to 2 kV. Currents of tens of amps were measured with a Rogowsky coil and plasma flow speeds of 4 km/s were inferred from high-speed images of jet propagation. An upgrade consisting in adding capacitors in parallel will be performed in order to increase the energy up to 2 kJ. A coil will be installed at the gun muzzle to compress the plasma flow and increase the energy density of the jet on the sample surface. A CCD camera with a maximum recording speed of 100 k fps and a maximum resolution of 1024 × 1024 pixels was set for image acquisition of the plasma and dust. A laser system used to illuminate the ejected dust from the surface includes a laser diode emitting at 650 nm with a beam power of 25 mW. The authors acknowledge support from EURATOM WP13-IPH-A03-P2-02-BS22.

  10. Three-dimensional measurement of small inner surface profiles using feature-based 3-D panoramic registration

    Science.gov (United States)

    Gong, Yuanzheng; Seibel, Eric J.

    2017-01-01

    Rapid development in the performance of sophisticated optical components, digital image sensors, and computer abilities along with decreasing costs has enabled three-dimensional (3-D) optical measurement to replace more traditional methods in manufacturing and quality control. The advantages of 3-D optical measurement, such as noncontact, high accuracy, rapid operation, and the ability for automation, are extremely valuable for inline manufacturing. However, most of the current optical approaches are eligible for exterior instead of internal surfaces of machined parts. A 3-D optical measurement approach is proposed based on machine vision for the 3-D profile measurement of tiny complex internal surfaces, such as internally threaded holes. To capture the full topographic extent (peak to valley) of threads, a side-view commercial rigid scope is used to collect images at known camera positions and orientations. A 3-D point cloud is generated with multiview stereo vision using linear motion of the test piece, which is repeated by a rotation to form additional point clouds. Registration of these point clouds into a complete reconstruction uses a proposed automated feature-based 3-D registration algorithm. The resulting 3-D reconstruction is compared with x-ray computed tomography to validate the feasibility of our proposed method for future robotically driven industrial 3-D inspection.

  11. Iceberg ploughmark features on bottom surface of the South-Eastern Baltic Sea

    Science.gov (United States)

    Dorokhov, Dmitry; Sivkov, Vadim; Dorokhova, Evgenia; Krechik, Viktor

    2016-04-01

    A detail swath bathymetry, side-scan sonar and acoustic profiling combined with sediment sampling during the 64th cruise of RV "Academic Mstislav Keldysh" (October 2015) allowed to identify new geomorphological features of the South-Eastern Baltic Sea bottom surface. The extended chaotic ploughmarks (furrows) in most cases filled with thin layer of mud were discovered on surface of the Gdansk-Gotland sill glacial deposits. They are observed on the depth of more than 70 m and have depth and width from 1 to 10 m. Most of them are v- or u-shaped stepped depressions. The side-scan records of similar geomorpholoical features are extensively reported from Northern Hemisphere and Antarctica (Goodwin et al., 1985; Dowdeswell et al., 1993). Ploughmarks are attributed to the action of icebergs scouring into the sediment as they touch bottom. We are suggest that furrows discovered in the South-Eastern Baltic Sea are also the result of iceberg scouring during the Baltic Ice Lake stage (more than 11 600 cal yr BP (Bjorck, 2008)). This assumption confirmed by occurrence of fragmental stones and boulders on the sea bottom surface which are good indicators of iceberg rafting (Lisitzin, 2003). Ice ploughmarks at sea bottom surface were not occurred before in the South-Eastern Baltic Sea. The study was financed by Russian Scientific Fund, grant number 14-37-00047. References Bjorck S. The late Quaternary development of the Baltic Sea Basin. In: The BACC Author Team (eds) Assessment of climate change for the Baltic Sea Basin. Springer, Berlin, Heidelberg. 2008. Dowdeswell J. A., Villinger H., Whittington R. J., Marienfeld P. Iceberg scouring in Scoresby Sund and on the East Greenland continental shelf // Marine Geology. V. 111. N. 1-2. 1993. P. 37-53. Goodwin C. R., Finley J. C., Howard L. M. Ice scour bibliography. Environmental Studies Revolving Funds Report No. 010. Ottawa. 1985. 99 pp. Lisitzin A. P. Sea-Ice and Iceberg Sedimentation in the Ocean: Recent and Past. Springer

  12. Short term memory for single surface features and bindings in ageing: A replication study.

    Science.gov (United States)

    Isella, Valeria; Molteni, Federica; Mapelli, Cristina; Ferrarese, Carlo

    2015-06-01

    In the present study we replicated a previous experiment investigating visuo-spatial short term memory binding in young and older healthy individuals, in the attempt to verify the pattern of impairment that can be observed in normal elderly for short term memory for single items vs short term memory for bindings. Assessing a larger sample size (25 young and 25 older subjects), using a more appropriate measure of accuracy for a change detection task (A'), and adding the evaluation of speed of performance, we confirmed that old normals show a decline in short term memory for bindings of shape and colour that is of comparable extent, and not major, to the decline in memory for single shapes and single colours. The absence of a specific deficit of short term memory for conjunctions of surface features seems to distinguish cognitive ageing from Alzheimer's Disease. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Rupture features of the 2010 Mw 8.8 Chile earthquake extracted from surface waves

    Science.gov (United States)

    Huang, Yi-Ling; Hwang, Ruey-Der; Jhuang, Yi-Shan; Lin, Cai-Yi

    2017-03-01

    This study used the rupture directivity theory to derive the fault parameters of the 2010 Mw 8.8 Chile earthquake on the basis of the azimuth-dependent source duration obtained from the Rayleigh-wave phase velocity. Results revealed that the 2010 Chile earthquake featured asymmetric bilateral faulting. The two rupture directions were N171°E (northward) and N17°E (southward), with rupture lengths of approximately 313 and 118 km, respectively, and were related to the locking degree in the source region. The entire source duration was approximately 187 s. After excluding the rise time from the source duration, the northward rupture velocity was approximately 2.02 km/s, faster than the southward rupture velocity (1.74 km/s). On average, the rupture velocity derived from this study was slower than that estimated from finite-fault inversion; however, several historical earthquakes in the Chile region also showed slow rupture velocity when using low-frequency signals, as surface waves do. Two earlier studies through global-positioning-system data analysis showed that the static stress drop of 50-70 bars for the 2010 Chile earthquake was higher than that for subduction-zone earthquakes. Hence, a remarkable feature was that the 2010 Chile earthquake had a slow rupture velocity and a high static stress drop, which suggested an inverse relationship between rupture velocity and static stress drop.[Figure not available: see fulltext.

  14. WORKING FEATURES OF POWER SOURCE SYSTEMS – A MULTIPLE CURRENT PULSE GENERATOR

    Directory of Open Access Journals (Sweden)

    Shs.V. Argun

    2013-04-01

    Full Text Available An analysis of circuit designs as to connecting a magnetic pulse action tool to a power source has been carried out. Design features of a magnetic pulse installation control and monitoring system in a multiple current pulse mode have been revealed. The description of the control and monitoring system block diagrams has been presented.

  15. Second generation graphene: Opportunities and challenges for surface science

    Science.gov (United States)

    Agnoli, Stefano; Granozzi, Gaetano

    2013-03-01

    Graphene is an extremely intriguing material that is arousing a formidable amount of interest in many different disciplines. Surface science has not been immune to this fascination and has quickly made its contribution to the synthesis and study of the fundamental properties of systems like epitaxial graphene films, nanoribbons, nanopatches, providing a basic knowledge, which has been successfully capitalized upon by technologists and material scientists. Nowadays, the focus of scientists' attention has moved towards more complex systems like chemically modified graphene and 3D systems based on the assembly of graphene sheets. However, despite many successful applications and the synthesis of very different materials, a basic understanding of the phenomena taking place at the atomic level is still missing, as is a clear correlation between structure and properties. Surface science, by virtue of its reductionist approach, can certainly make an important contribution to these new branches of research. Graphene is a perfect candidate for the realization of highly controlled model systems, in which to study the evolution from 2D to 3D topology or the new properties engendered by the substitution of carbon atoms with selected heteroatoms or entire functional groups. Graphene has also proved to be an effective and versatile support: by acting on the nanostructure and defectivity of carbon sheets, it is possible to obtain highly controlled and easily tunable nanoparticles, opening the way to the rational design of new materials, and to the development of quite powerful model systems for heterogeneous catalysis investigations. Finally, graphene has proven to be extremely interesting as an advanced electrode for many electrochemical applications, and the study of the phenomena taking place at the solid-electrolyte interface is of paramount importance. This field could be the perfect context where the newly born discipline, electrochemical surface science, can advance and

  16. Specific Features of Chip Making and Work-piece Surface Layer Formation in Machining Thermal Coatings

    Directory of Open Access Journals (Sweden)

    V. M. Yaroslavtsev

    2016-01-01

    Full Text Available A wide range of unique engineering structural and performance properties inherent in metallic composites characterizes wear- and erosion-resistant high-temperature coatings made by thermal spraying methods. This allows their use both in manufacturing processes to enhance the wear strength of products, which have to operate under the cyclic loading, high contact pressures, corrosion and high temperatures and in product renewal.Thermal coatings contribute to the qualitative improvement of the technical level of production and product restoration using the ceramic composite materials. However, the possibility to have a significantly increased product performance, reduce their factory labour hours and materials/output ratio in manufacturing and restoration is largely dependent on the degree of the surface layer quality of products at their finishing stage, which is usually provided by different kinds of machining.When machining the plasma-sprayed thermal coatings, a removing process of the cut-off layer material is determined by its distinctive features such as a layered structure, high internal stresses, low ductility material, high tendency to the surface layer strengthening and rehardening, porosity, high abrasive properties, etc. When coatings are machined these coating properties result in specific characteristics of chip formation and conditions for formation of the billet surface layer.The chip formation of plasma-sprayed coatings was studied at micro-velocities using an experimental tool-setting microscope-based setup, created in BMSTU. The setup allowed simultaneous recording both the individual stages (phases of the chip formation process and the operating force factors.It is found that formation of individual chip elements comes with the multiple micro-cracks that cause chipping-off the small particles of material. The emerging main crack in the cut-off layer of material leads to separation of the largest chip element. Then all the stages

  17. Unusual features associated with dentinogenesis imperfecta type II: report of two cases affecting the family over three generations

    Directory of Open Access Journals (Sweden)

    Shruthi Rao

    2017-03-01

    Full Text Available Dentinogenesis imperfecta (DI is an autosomal dominant genetic disease. It has a high degree of penetrance and a very low mutation rate. DI is characterized by opalescent dentin and discoloration of the teeth. The exposed dentin may undergo severe attrition. Early diagnosis and management of this condition is essential for the prevention of further complications and for the aesthetic purpose. We present clinical and radiographic features of two cases of DI type II affecting the family over three generations. This report also highlights rare features such as odontome, multiple impacted teeth and retained deciduous teeth along with features of DI in a 16-years old male.. [Cukurova Med J 2017; 42(1.000: 155-160

  18. FEATURES SOCIALIZATION STUDENTS OF THE BOARDING SCHOOL IN THE FAR NORTH IN CONDITIONS OF INTRODUCTUIN OF THE GEF SECOND GENERATION

    Directory of Open Access Journals (Sweden)

    Zimin Aleksei Valerevich

    2013-02-01

    Full Text Available Purpose. Study the features of the socialization of students, of the efficiency of primary school textbooks, with the introduction of the federal state educational standards of the second generation-specific institution. Methodology. Questionnaire and the study of literature and documents. Results. As a result of the original research report the presence of three groups of students, requiring consideration of ethnic features when planning learning activities. The features of the formation of ethnic socialization boarding schools. The conclusions about the lack of effectiveness of the selection and application of teaching and learning materials to meet the specific conditions of the environment of students - students of the boarding school, to work towards improving the quality of training of the teaching staff of boarding schools. Practical implications. Methodical and personnel support of the educational process in the open secondary boarding schools in the Far North.

  19. Next Generation Structural Composite Using Surface Grown Carbon Nanotubes

    Science.gov (United States)

    2012-10-01

    Marwan  Al‐Haik (Virginia Tech, Mechanical Engineering)  3‐ Claudi Luhrs (Co‐PI, UNM, Mechanical Engineering)  4‐ Hamid Garmestani (Georgia Tech, Mechanical...Taha  Army  Office  of  Research  Award:  DURIP:  High  Velocity  Impact  Equipment, May 2010.  5. Dr  Marwan   Al‐Haik  and  Dr. Mahmoud  Reda  Taha...Chavez.   Honor Undergraduate Thesis, Growth of carbon nanotubes/nanofibers on the  surface  of  carbon  fibers.  Advisor  Marwan   Al‐Haik  May  2009

  20. Effects of Surface Chemistry on the Generation of Reactive Oxygen Species by Copper Nanoparticles

    Science.gov (United States)

    Shi, Miao; Kwon, Hyun Soo; Peng, Zhenmeng; Elder, Alison; Yang, Hong

    2012-01-01

    Mercaptocarboxylic acids with different carbon chain lengths were used for stabilizing uniform 15 nm copper nanoparticles. The effects of surface chemistry such as ligand type and surface oxidation on the reactive oxygen species (ROS) generated by the copper nanoparticles were examined. Transmission electron microscopy (TEM), Powder X-ray diffraction (PXRD), UV-vis spectroscopy, and an acellular ROS assay show that ROS generation is closely related to the surface oxidation of copper nanoparticles. It was found that the copper nanoparticles with longer chain ligands had surfaces that were better protected from oxidation and a corresponding lower ROS generating capacity than did particles with shorter chain ligands. Conversely, the copper nanoparticles with greater surface oxidation also had higher ROS generating capacity. PMID:22390268

  1. A Near-Infrared and Thermal Imager for Mapping Titan's Surface Features

    Science.gov (United States)

    Aslam, S.; Hewagma, T.; Jennings, D. E.; Nixon, C.

    2012-01-01

    Approximately 10% of the solar insolation reaches the surface of Titan through atmospheric spectral windows. We will discuss a filter based imaging system for a future Titan orbiter that will exploit these windows mapping surface features, cloud regions, polar storms. In the near-infrared (NIR), two filters (1.28 micrometer and 1.6 micrometer), strategically positioned between CH1 absorption bands, and InSb linear array pixels will explore the solar reflected radiation. We propose to map the mid, infrared (MIR) region with two filters: 9.76 micrometer and 5.88-to-6.06 micrometers with MCT linear arrays. The first will map MIR thermal emission variations due to surface albedo differences in the atmospheric window between gas phase CH3D and C2H4 opacity sources. The latter spans the crossover spectral region where observed radiation transitions from being dominated by thermal emission to solar reflected light component. The passively cooled linear arrays will be incorporated into the focal plane of a light-weight thin film stretched membrane 10 cm telescope. A rad-hard ASIC together with an FPGA will be used for detector pixel readout and detector linear array selection depending on if the field-of-view (FOV) is looking at the day- or night-side of Titan. The instantaneous FOV corresponds to 3.1, 15.6, and 31.2 mrad for the 1, 5, and 10 micrometer channels, respectively. For a 1500 km orbit, a 5 micrometer channel pixel represents a spatial resolution of 91 m, with a FOV that spans 23 kilometers, and Titan is mapped in a push-broom manner as determined by the orbital path. The system mass and power requirements are estimated to be 6 kg and 5 W, respectively. The package is proposed for a polar orbiter with a lifetime matching two Saturn seasons.

  2. Beacons and surface features differentially influence human reliance on global and local geometric cues when reorienting in a virtual environment.

    Science.gov (United States)

    Bodily, Kent D; Kilday, Zachary A; Eastman, Caroline K; Gaskin, Katherine A; Graves, April A; Roberts, Jonathan E; Sturz, Bradley R

    2013-02-01

    In the reorientation literature, non-geometric cues include discrete objects (e.g., beacons) and surface-based features (e.g., colors, textures, and odors). To date, these types of non-geometric cues have been considered functionally similar, and it remains unknown whether beacons and surface features differentially influence the extent to which organisms reorient via global and local geometric cues. In the present experiment, we trained human participants to approach a location in a trapezoid-shaped enclosure uniquely specified by global and local geometric cues. We explored the role of beacons on the use of geometric cues by training participants in the presence or absence of uniquely-colored beacons. We explored the role of surface features on the use of geometric cues by recoloring two adjacent walls at the correct location and/or adding a line on the floor which corresponded to the major principal axis of the enclosure. All groups were then tested in novel-shaped enclosures in the absence of unique beacons and surface features to assess the relative use of global and local geometric cues. Results suggested that beacons facilitated the use of global geometric cues, whereas surface features either facilitated or hindered the use of geometric cues, depending on the feature. Published by Elsevier B.V.

  3. DISCRETIZATION APPROACH USING RAY-TESTING MODEL IN PARTING LINE AND PARTING SURFACE GENERATION

    Institute of Scientific and Technical Information of China (English)

    HAN Jianwen; JIAN Bin; YAN Guangrong; LEI Yi

    2007-01-01

    Surface classification, 3D parting line, parting surface generation and demoldability analysis which is helpful to select optimal parting direction and optimal parting line are involved in automatic cavity design based on the ray-testing model. A new ray-testing approach is presented to classify the part surfaces to core/cavity surfaces and undercut surfaces by automatic identifying the visibility of surfaces. A simple, direct and efficient algorithm to identify surface visibility is developed. The algorithm is robust and adapted to rather complicated geometry, so it is valuable in computer-aided mold design systems. To validate the efficiency of the approach, an experimental program is implemented. Case studies show that the approach is practical and valuable in automatic parting line and parting surface generation.

  4. Application of a new feature extraction and optimization method to surface defect recognition of cold rolled strips

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Considering that the surface defects of cold rolled strips are hard to be recognized by human eyes under high-speed circumstances, an automatic recognition technique was discussed. Spectrum images of defects can be got by fast Fourier transform (FFT) and sum of valid pixels (SVP), and its optimized center region, which concentrates nearly all energies, are extracted as an original feature set. Using genetic algorithm to optimize the feature set, an optimized feature set with 51 features can be achieved.Using the optimized feature set as an input vector of neural networks, the recognition effects of LVQ neural networks have been studied. Experiment results show that the new method can get a higher classification rate and can settle the automatic recognition problem of surface defects on cold rolled strips ideally.

  5. Estimation of glacier surface motion by robust phase correlation and point like features of SAR intensity images

    Science.gov (United States)

    Fang, Li; Xu, Yusheng; Yao, Wei; Stilla, Uwe

    2016-11-01

    For monitoring of glacier surface motion in pole and alpine areas, radar remote sensing is becoming a popular technology accounting for its specific advantages of being independent of weather conditions and sunlight. In this paper we propose a method for glacier surface motion monitoring using phase correlation (PC) based on point-like features (PLF). We carry out experiments using repeat-pass TerraSAR X-band (TSX) and Sentinel-1 C-band (S1C) intensity images of the Taku glacier in Juneau icefield located in southeast Alaska. The intensity imagery is first filtered by an improved adaptive refined Lee filter while the effect of topographic reliefs is removed via SRTM-X DEM. Then, a robust phase correlation algorithm based on singular value decomposition (SVD) and an improved random sample consensus (RANSAC) algorithm is applied to sequential PLF pairs generated by correlation using a 2D sinc function template. The approaches for glacier monitoring are validated by both simulated SAR data and real SAR data from two satellites. The results obtained from these three test datasets confirm the superiority of the proposed approach compared to standard correlation-like methods. By the use of the proposed adaptive refined Lee filter, we achieve a good balance between the suppression of noise and the preservation of local image textures. The presented phase correlation algorithm shows the accuracy of better than 0.25 pixels, when conducting matching tests using simulated SAR intensity images with strong noise. Quantitative 3D motions and velocities of the investigated Taku glacier during a repeat-pass period are obtained, which allows a comprehensive and reliable analysis for the investigation of large-scale glacier surface dynamics.

  6. Surface spin-polarized currents generated in topological insulators by circularly polarized synchrotron radiation and their photoelectron spectroscopy indication

    Science.gov (United States)

    Shikin, A. M.; Klimovskikh, I. I.; Filyanina, M. V.; Rybkina, A. A.; Pudikov, D. A.; Kokh, K. A.; Tereshchenko, O. E.

    2016-08-01

    A new method for generating spin-polarized currents in topological insulators has been proposed and investigated. The method is associated with the spin-dependent asymmetry of the generation of holes at the Fermi level for branches of topological surface states with the opposite spin orientation under the circularly polarized synchrotron radiation. The result of the generation of holes is the formation of compensating spin-polarized currents, the value of which is determined by the concentration of the generated holes and depends on the specific features of the electronic and spin structures of the system. The indicator of the formed spin-polarized current can be a shift of the Fermi edge in the photoelectron spectra upon photoexcitation by synchrotron radiation with the opposite circular polarization. The topological insulators with different stoichiometric compositions (Bi1.5Sb0.5Te1.8Se1.2 and PbBi2Se2Te2) have been investigated. It has been found that there is a correlation in the shifts and generated spin-polarized currents with the specific features of the electronic spin structure. Investigations of the graphene/Pt(111) system have demonstrated the possibility of using this method for other systems with a spin-polarized electronic structure.

  7. How Activism Features in the Career Lives of Four Generations of Canadian Nurses.

    Science.gov (United States)

    MacDonnell, Judith A; Buck-McFadyen, Ellen

    2016-11-01

    Recent nursing research using a critical feminist lens challenges the prevailing view of political inertia in nursing. This comparative life history study using a critical feminist lens explores the relevance of activism with four generations of Canadian nurses. Purposeful sampling of Ontario nurses resulted in 40 participants who were diverse in terms of generation, practice setting, and activist practice. Interviews and focus groups were completed with the sample of Ontario registered nurses or undergraduate and graduate nursing students: 8 Generation X, 9 Generation Y (Millennials), 20 Boomers, and 3 Overboomers. Factors such as professional norms and personal and organizational supports shaped contradictory nursing activist identities, practices, and impacts. Gendered norms, organizational dynamics, and the political landscape influenced the meanings nurses attributed to critical incidents and influences that prompted activism inside and outside the workplace, shaping the transformative potential of nursing. Despite its limitations, the study has implications for creating professional and organizational supports for consideration of health politics and policy, and spaces for dialogue to support practice and research aligned with social justice goals.

  8. Determination of Surface Stress Distributions in Steel Using Laser-Generated Surface Acoustic Waves

    Science.gov (United States)

    Shi; Yifei; Ni; Chenyin; Shen; Zhonghua; Ni; Xiaowu; Lu; Jian

    2008-05-01

    High frequency surface acoustic waves (SAWs) are excited by a pulsed laser and detected by a specially designed poly(vinylidene fluoride) (PVDF) transducer to investigate surface stress distribution. Two kinds of stressed surfaces are examined experimentally. One is a steel plate elastically deformed under simple bending forces, where the surface stress varies slowly. The other is a welded steel plate for which the surface stress varies very rapidly within a small area near the welding seam. Applying a new signal processing method developed from correlation technique, the velocity distribution of the SAWs, which reflects the stress distribution, is obtained in these two samples with high resolution.

  9. An automatic grid generation approach over free-form surface for architectural design

    Institute of Scientific and Technical Information of China (English)

    苏亮; 祝顺来; 肖南; 高博青

    2014-01-01

    An essential step for the realization of free-form surface structures is to create an efficient structural gird that satisfies not only the architectural aesthetics, but also the structural performance. Employing the main stress trajectories as the representation of force flows on a free-form surface, an automatic grid generation approach is proposed for the architectural design. The algorithm automatically plots the main stress trajectories on a 3D free-form surface, and adopts a modified advancing front meshing technique to generate the structural grid. Based on the proposed algorithm, an automatic grid generator named “St-Surmesh” is developed for the practical architectural design of free-form surface structure. The surface geometry of one of the Sun Valleys in Expo Axis for the Expo Shanghai 2010 is selected as a numerical example for validating the proposed approach. Comparative studies are performed to demonstrate how different structural grids affect the design of a free-form surface structure.

  10. A fast direct point-by-point generating algorithm for B Spline curves and surfaces

    Institute of Scientific and Technical Information of China (English)

    LI Zhong; HAN Dan-fu

    2005-01-01

    Traditional generating algorithms for B Spline curves and surfaces require approximation methods where how to increment the parameter to get the best approximation is problematic; or they take the pixel-based method needing matrix transformation from B Spline representation to Bezier form. Here, a fast, direct point-by-point generating algorithm for B Spline curves and surfaces is presented. The algorithm does not need matrix transformation, can be used for uniform or nonuniform B Spline curves and surfaces of any degree, and has high generating speed and good rendering accuracy.

  11. Generating optical freeform surfaces considering both coordinates and normals of discrete data points.

    Science.gov (United States)

    Zhu, Jun; Wu, Xiaofei; Yang, Tong; Jin, Guofan

    2014-11-01

    Through direct design methods, both coordinates and normals of discrete data points on a freeform surface are usually obtained, but traditionally the freeform surface is generated by only fitting the coordinates. In this paper, a novel generating method that fits both the coordinates and the normals is proposed based on the mathematical multiobjective optimization theory. This new method is suited for generating some freeform polynomial surfaces. Two design examples are introduced, and their optical performance is significantly improved when applying the new method compared with the traditional method. This new method is validated to be effective, and it is widely useful as long as the coordinates and the normals are provided in advance.

  12. Economical and Morpho-Biological Features of Whiner Wheat New Generation Varieties (Triticum durum

    Directory of Open Access Journals (Sweden)

    Л. І. Улич

    2010-10-01

    Full Text Available The article describes summary of the researches, characteristics of morphological and agro-biological characteristics and features, a note is made of a significant progress in the selection of productivity and adaptability of registered Durum Winter Wheat Varieties of new crops rotation. Significant developments of  plants architectonic are marked, especially in height, characteristics of economical value, and in terms of considerable achievements in breeding of this kind of wheat. A stress in made on the need to enhance Durum Winter Wheat breeding to develop more frostresistant and drought-overheat resistant varieties.

  13. Surface and upper air meteorological features during onset phase of 2003 monsoon

    Indian Academy of Sciences (India)

    O P Singh; H R Hatwar; Onkari Prasad

    2007-08-01

    The second campaign of the Arabian Sea Monsoon Experiment (ARMEX-II) was conducted in two phases viz., March–April and May–June 2003. In the present work, the buoy and ocean research vessel data collected during the second phase of ARMEX-II have been analysed to bring out the characteristic features of monsoon onset. The results have shown that the thermodynamical features such as build up of lower tropospheric instability and increased height of zero degree isotherm occurred about a week before the monsoon onset over Kerala and adjoining southeast Arabian Sea. There was a sharp fall in the temperature difference between 850 and 500 hPa, and the height of zero degree isotherm about 2–3 days before the monsoon onset. The flux of sensible heat was positive (sea to air) over south Arabian Sea during the onset phase. Over the Bay of Bengal higher negative (air to sea) values of sensible flux prevailed before the monsoon onset which became less negative with the advance of monsoon over that region. The pre-onset period was characterized by large sea surface temperature (SST) gradient over the Arabian Sea with rapid decrease towards north of the warm pool region. The buoy observations have shown that SST remained close to 30.5°C in the warm pool region during the pre-onset period in 2003 but only 2–3 degrees away (north of this region) SSTs were as low as 28.5-29°C. An interesting aspect of sea level pressure (SLP) variability over the Indian seas during the onset phase of summer monsoon 2003 was undoubtedly, the highest SLP in the warm pool region inspite of very high SSTs.

  14. Chronological analysis with fluorescent timer reveals unique features of newly generated β-cells.

    Science.gov (United States)

    Miyatsuka, Takeshi; Matsuoka, Taka-aki; Sasaki, Shugo; Kubo, Fumiyo; Shimomura, Iichiro; Watada, Hirotaka; German, Michael S; Hara, Manami

    2014-10-01

    Although numerous studies have uncovered the molecular mechanisms regulating pancreas development, it remains to be clarified how β-cells arise from progenitors and how recently specified β-cells are different from preexisting β-cells. To address these questions, we developed a mouse model in which the insulin 1 promoter drives DsRed-E5 Timer fluorescence that shifts its spectrum over time. In transgenic embryos, green fluorescent β-cells were readily detected by FACS and could be distinguished from mature β-cells only until postnatal day 0, suggesting that β-cell neogenesis occurs exclusively during embryogenesis. Transcriptome analysis with green fluorescent cells sorted by FACS demonstrated that newly differentiated β-cells highly expressed progenitor markers, such as Sox9, Neurog3, and Pax4, showing the progenitor-like features of newborn β-cells. Flow cytometric analysis of cell cycle dynamics showed that green fluorescent cells were mostly quiescent, and differentiated β-cells were mitotically active. Thus, the precise temporal resolution of this model enables us to dissect the unique features of newly specified insulin-producing cells, which could enhance our understanding of β-cell neogenesis for future cell therapy. © 2014 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  15. Surface enhanced second harmonic generation from macrocycle, catenane, and rotaxane thin films : Experiments and theory

    NARCIS (Netherlands)

    Arfaoui, [No Value; Bermudez, [No Value; Bottari, G; De Nadai, C; Jalkanen, JP; Kajzar, F; Leigh, DA; Lubomska, M; Mendoza, SM; Niziol, J; Rudolf, P; Zerbetto, F; Arfaoui, Imad; Bermúdez, Verónica; Jalkanen, Jukka-Pekka

    2006-01-01

    Surface enhanced second harmonic generation (SE SHG) experiments on molecular structures, macrocycles, catenanes, and rotaxanes, deposited as monolayers and multilayers by vacuum sublimation on silver, are reported. The measurements show that the molecules form ordered thin films, where the highest

  16. Study of Distinctive Regional Features of Surface Solar Radiation in North and East China

    Institute of Scientific and Technical Information of China (English)

    关福来; 郑有飞; 蔡子颖; 于长文; 张楠

    2011-01-01

    Solar radiation is an important energy source for plants on the earth and also a major component of the global energy balance.Variations in solar radiation incident at the earth's surface profoundly affect the human and terrestrial environment,including the climate change.To provide useful information for predicting the future climate change in China,distinctive regional features in spatial and temporal variations of the surface solar radiation (SSR) and corresponding attributions (such as cloud and aerosol) are analyzed based on SSR observations and other meteorological measurements in North and East China from 1961 to 2007.Multiple models,such as the plane-parallel radiative transfer model,empirical and statistical models,and corrclation and regrcssion analysis methods are used in the study.The results are given as follows.(1) During 1961-2007,the total SSR in North China went through a process from quickly “dimming” to slowly “dimming”,while in East China,a significant transition from “dimming” to “brightening” occurred.Although there are some differences between thc two regional variation trends,long-term variations in SSR in the two regions are basically consistent with the observation worldwide.(2) Between the 1960s and 1980s,in both North and East China,aerosols played a critical rolc in the radiation dimming.However,after 1989,different variation trends of SSR occurred in North and East China,indicating that aerosols were not the dominant factor.(3) Cloud cover contributed less to the variation of SSR in North China,but was thc major attribution in East China and played a promoting role in the reversal of SSR from dimming to brightening,especially in the “remarkable brightening” period,with its contribution as high as 70%.

  17. Robust affine-invariant feature points matching for 3D surface reconstruction of complex landslide scenes

    Science.gov (United States)

    Stumpf, André; Malet, Jean-Philippe; Allemand, Pascal; Skupinski, Grzegorz; Deseilligny, Marc-Pierrot

    2013-04-01

    Multi-view stereo surface reconstruction from dense terrestrial photographs is being increasingly applied for geoscience applications such as quantitative geomorphology, and a number of different software solution and processing streamlines have been suggested. For image matching, camera self-calibration and bundle block adjustment, most approaches make use of scale-invariant feature transform (SIFT) to identify homologous points in multiple images. SIFT-like point matching is robust to apparent translation, rotation, and scaling of objects in multiple viewing geometries but the number of correctly identified matching points typically declines drastically with increasing angles between the viewpoints. For the application of multi-view stereo of complex landslide scenes, the viewing geometry is often constrained by the local topography and barriers such as rocks and vegetation occluding the target. Under such conditions it is not uncommon to encounter view angle differences of > 30% that hinder the image matching and eventually prohibit the joint estimation of the camera parameters from all views. Recently an affine invariant extension of the SIFT detector (ASIFT) has been demonstrated to provide more robust matches when large view-angle differences become an issue. In this study the ASIFT detector was adopted to detect homologous points in terrestrial photographs preceding 3D reconstruction of different parts (main scarp, toe) of the Super-Sauze landslide (Southern French Alps). 3D surface models for different time periods and different parts of the landslide were derived using the multi-view stereo framework implemented in MicMac (©IGN). The obtained 3D models were compared with reconstructions using the traditional SIFT detectors as well as alternative structure-from-motion implementations. An estimate of the absolute accuracy of the photogrammetric models was obtained through co-registration and comparison with high-resolution terrestrial LiDAR scans.

  18. Nanosecond pulsed laser induced generation of open macro porosity on sintered ZnO pellet surface

    Energy Technology Data Exchange (ETDEWEB)

    Singh, A.K., E-mail: anilks@barc.gov.in [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai (India); Samanta, Soumen [Technical Physics Division, Bhabha Atomic Research Centre, Mumbai (India); Sinha, Sucharita [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai (India)

    2015-01-15

    Highlights: • Zinc oxide (ZnO) targets have been surface treated using a frequency doubled nanosecond pulsed Nd:YAG laser at laser fluence levels ranging between 2 and 9 J/cm{sup 2}. • Our observations establish that laser irradiation provides an effective technique for generation of surface macro porosity in case of ZnO pellets. • Extent of surface porosity and the mean pore size could be controlled by appropriately varying the incident laser fluence. • Such laser treated ZnO surfaces with enhanced surface porosity and large size pores (mean pore area ∼2–5 μm{sup 2}) can serve as potential candidate for humidity sensors with high sensitivity and fast response time, particularly in high humidity range. - Abstract: Surface porosity and pore size distribution of sensing material greatly influence performance parameters such as sensitivity, reproducibility and response time of sensors. Various approaches have been employed to generate surface porosity having varying pore size distribution. This paper presents our results on pulsed laser irradiation based surface microstructuring of sintered zinc oxide (ZnO) pellets leading to generation of enhanced surface porosity. ZnO targets have been surface treated using a frequency doubled nanosecond pulsed Nd:YAG laser at laser fluence levels ranging between 2 and 9 J/cm{sup 2}. Our observations establish that laser irradiation provides an effective technique for generation of surface macro porosity in case of ZnO pellets. Also, extent of surface porosity and the mean pore size could be controlled by appropriately varying the incident laser fluence. Such laser treated ZnO surfaces with enhanced surface porosity and large size pores can serve as potential candidate for humidity sensors with high sensitivity and fast response time, particularly in high humidity range.

  19. Automated Music Video Generation Using Multi-level Feature-based Segmentation

    Science.gov (United States)

    Yoon, Jong-Chul; Lee, In-Kwon; Byun, Siwoo

    The expansion of the home video market has created a requirement for video editing tools to allow ordinary people to assemble videos from short clips. However, professional skills are still necessary to create a music video, which requires a stream to be synchronized with pre-composed music. Because the music and the video are pre-generated in separate environments, even a professional producer usually requires a number of trials to obtain a satisfactory synchronization, which is something that most amateurs are unable to achieve.

  20. FEATURES OF ISLET-LIKE CLUSTERS GENERATION IN PANCREATIC DUCTAL CELL MOLOLAYER CULTURING

    Directory of Open Access Journals (Sweden)

    L. A. Kirsanova

    2012-01-01

    Full Text Available Newborn rabbit pancreatic cell monolayer was obtained as we described earlier.The cultivated epithelial cells were shown by immunofluorescence to express special ductal marker CK19 and were insulin-and glucagon- negative for 10–15 days. A few fusiforms of nestin-positive cells were found in monolayer. Over 2 weeks in serum-free medium the plaques of epithelial cells became crowded and formed 3-dimentional structures – islet- like clusters. Islet-like clusters contain some insulin- and glucagon-positive cells recognized by immunohysto- chemistry staining. Pancreatic endocrine cell generation in 3-dimentional structures is discussed. 

  1. Information seeking as idea-generating and -stabilizing feature in entrepreneurship courses at university

    DEFF Research Database (Denmark)

    Schreiber, Trine Louise

    2017-01-01

    , information seeking and sharing supported both generation and stabilization of ideas as potential existing objects. Conclusion. The investigation of written assignments from the entrepreneurship courses indicates that a certain variation of information activities formed part of the learning process......Introduction. The aim of the paper is to analyze the kind of written assignment, which was applied in three entrepreneurship courses in higher education, and to examine how this kind of assignment shaped and was shaped by students´ information seeking. Method. The study is based on an empirical...

  2. A Circular Polarizer with Beamforming Feature Based on Frequency Selective Surfaces

    Science.gov (United States)

    Yin, Jia Yuan; Wan, Xiang; Ren, Jian; Cui, Tie Jun

    2017-01-01

    We propose a circular polarizer with beamforming features based on frequency selective surface (FSS), in which a modified anchor-shaped unit cell is used to reach the circular polarizer function. The beamforming characteristic is realized by a particular design of the unit-phase distribution, which is obtained by varying the scale of the unit cell. Instead of using plane waves, a horn antenna is designed to feed the phase-variant FSS. The proposed two-layer FSS is fabricated and measured to verify the design. The measured results show that the proposed structure can convert the linearly polarized waves to circularly polarized waves. Compared with the feeding horn antenna, the transmitted beam of the FSS-added horn is 14.43° broader in one direction, while 3.77° narrower in the orthogonal direction. To our best knowledge, this is the first time to realize circular polarizer with beamforming as the extra function based on FSS, which is promising in satellite and communication systems for potential applications due to its simple design and good performance.

  3. Gross Morphological Features of the Organ Surface Primo-Vascular System Revealed by Hemacolor Staining

    Directory of Open Access Journals (Sweden)

    Chae Jeong Lim

    2013-01-01

    Full Text Available The primo-vascular system (PVS, which consists of primo-vessels (PVs and primo-nodes (PNs, is a novel thread-like structure identified in many animal species. Various observational methods have been used to clarify its anatomical properties. Here, we used Hemacolor staining to examine the gross morphology of organ-surface PVS in rats. We observed a sinus structure (20–50 μm with a remarkably low cellularity within PNs and PVs and several lines of ductules (3–5 μm filled with single cells or granules (~1 μm in PV. Both sinuses and ductules were linearly aligned along the longitudinal axis of the PVS. Such morphology of the PVS was further confirmed by acridine orange staining. In PN slices, there was a honeycomb-like structure containing the granules with pentagonal lumens (~10 μm. Both PVs and PNs were densely filled with WBCs, RBCs, and putative mast cells (MCs, which were 90.3%, 5.9%, and 3.8% of the cell population, respectively. Granules in putative MCs showed spontaneous vibrating movements. In conclusion, the results show that Hemacolor, a simple and rapid staining system, can reveal the gross morphological features reported previously. Our findings may help to elucidate the structure and function of the PVS in normal and disease states in future studies.

  4. A Circular Polarizer with Beamforming Feature Based on Frequency Selective Surfaces

    Science.gov (United States)

    Yin, Jia Yuan; Wan, Xiang; Ren, Jian; Cui, Tie Jun

    2017-01-01

    We propose a circular polarizer with beamforming features based on frequency selective surface (FSS), in which a modified anchor-shaped unit cell is used to reach the circular polarizer function. The beamforming characteristic is realized by a particular design of the unit-phase distribution, which is obtained by varying the scale of the unit cell. Instead of using plane waves, a horn antenna is designed to feed the phase-variant FSS. The proposed two-layer FSS is fabricated and measured to verify the design. The measured results show that the proposed structure can convert the linearly polarized waves to circularly polarized waves. Compared with the feeding horn antenna, the transmitted beam of the FSS-added horn is 14.43° broader in one direction, while 3.77° narrower in the orthogonal direction. To our best knowledge, this is the first time to realize circular polarizer with beamforming as the extra function based on FSS, which is promising in satellite and communication systems for potential applications due to its simple design and good performance. PMID:28128345

  5. Generation of Air/SF6 Interface with Minimum Surface Feature by Soap Film Technique

    Science.gov (United States)

    Wang, Xiansheng; Si, Ting; Luo, Xisheng; Yang, Jiming

    The Richtmyer-Meshkov (RM) instability occurs on an initially perturbed interface subjecting to a sudden acceleration by a shock [2]. Due to the deposition of baroclinic vorticity, the initial perturbation will grow with time, which generally intensifies the mixing between fluids and eventually induces turbulence in flow. Because of its academic significance in vortex dynamics and turbulent mixing as well as wide applications ranging from inertial confinement fusion, supernova explosions to supersonic combustion, the hydrodynamic instability becomes increasingly attractive. Specifically, several comprehensive reviews on this topic have been made [1, 2, 3].

  6. Online Monitoring of Laser-Generated XUV Radiation Spectra by Surface Reflectivity Measurements with Particle Detectors

    Directory of Open Access Journals (Sweden)

    Andreas Hoffmann

    2017-01-01

    Full Text Available In this contribution, we present a wavelength-sensitive method for the detection of extreme ultraviolet (XUV photon energies between 30 eV and 120 eV. The method is based on 45° reflectivity from either a cesium iodide-coated or an uncoated metal surface, which directs the XUV beam onto an electron or ion detector and its signal is used to monitor the XUV beam. The benefits of our approach are a spectrally sensitive diagnosis of the XUV radiation at the interaction place of time-resolved XUV experiments and the detection of infrared leak light though metal filters in high-harmonic generation (HHG experiments. Both features were tested using spectrally shaped XUV pulses from HHG in a capillary, and we have achieved excellent agreement with XUV spectrometer measurements and reflectivity calculations. Our obtained results are of interest for time-resolved XUV experiments presenting an additional diagnostic directly in the interaction region and for small footprint XUV beamline diagnostics.

  7. Generating grids directly on CAD database surfaces using a parametric evaluator approach

    Science.gov (United States)

    Gatzhe, Timothy D.; Melson, Thomas G.

    1995-01-01

    A very important, but often overlooked step in grid generation is acquiring a suitable geometry definition of the vehicle to be analyzed. In the past, geometry was usually obtained by generating a number of cross-sections of each component. A number of recent efforts have focussed on non-uniform rational B-spline surfaces (NURBS) to provide as single type of analytic surface to deal with inside the grid generator. This approach has required the development of tools to read other types of surfaces and convert them, either exactly or by approximation, into a NURBS surface. This paper describes a more generic parametric evaluator approach, which does not rely on a particular surface type internal to the grid generation system and is less restrictive in the number of surface types that can be represented exactly. This approach has been implemented in the McDonnell Douglas grid generation system, MACGS, and offers direct access to all types of surfaces from a Unigraphics part file.

  8. Surface plasmon polariton generation by light scattering off aligned organic nanofibers

    DEFF Research Database (Denmark)

    Skovsen, Esben; Søndergaard, Thomas; Fiutowski, Jacek

    2012-01-01

    Leakage radiation spectroscopy has been applied to study surface plasmon polariton (SPP) generation by light scattered off aligned organic nanofibers deposited on a thin silver film. The efficiency of SPP generation was studied by angularly resolved leakage radiation spectroscopy as a function...

  9. Information seeking as idea-generating and -stabilizing feature in entrepreneurship courses at university

    DEFF Research Database (Denmark)

    Schreiber, Trine Louise

    2017-01-01

    courses' learning objectives, the written assignments and the assignments' description of students' information seeking. Results. The students used information from the chosen sources as well as from the collected material to get inspiration for developing a project idea, refine it and justify it....... In this way, information seeking and sharing supported both generation and stabilization of ideas as potential existing objects. Conclusion. The investigation of written assignments from the entrepreneurship courses indicates that a certain variation of information activities formed part of the learning......Introduction. The aim of the paper is to analyse the kind of written assignment, which was applied in three entrepreneurship courses in higher education, and to examine how this kind of assignment shaped and was shaped by students' information seeking. Method. The study is based on an empirical...

  10. Oculo-facio-cardio-dental syndrome in three succeeding generations: genotypic data and phenotypic features

    Energy Technology Data Exchange (ETDEWEB)

    Lozić, B. [Department of Pediatrics, University Hospital Split, Split (Croatia); Ljubković, J. [Department of Pathology, Forensic Medicine and Cytology, University Hospital Split, Split (Croatia); Gabrić Pandurić, D. [Department of Oral Surgery, School of Dental Medicine, University of Zagreb, Zagreb (Croatia); Saltvig, I. [Jessenius Faculty of Medicine of Commenius, University in Bratislava, Martin (Slovakia); Kutsche, K. [Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg (Germany); Krželj, V. [Department of Pediatrics, University Hospital Split, Split (Croatia); Zemunik, T. [Department of Medical Biology, School of Medicine, University of Split, Split (Croatia)

    2012-09-21

    Oculo-facio-cardio-dental (OFCD) syndrome is a rare X-linked disorder mainly manifesting in females. Patients show ocular, facial, cardiac, and dental abnormalities. OFCD syndrome is caused by heterozygous mutations in the BCOR gene, located in Xp11.4, encoding the BCL6 co-repressor. We report a Croatian family with four female members (grandmother, mother and monozygotic female twins) diagnosed with OFCD syndrome who carry the novel BCOR mutation c.4438C>T (p.R1480*). They present high intrafamilial phenotypic variability with special regard to cardiac defect and cataract that showed more severe disease expression in successive generations. Clinical and radiographic examination of the mother of the twins revealed a talon cusp involving the permanent maxillary right central incisor. This is the first known report of a talon cusp in OFCD syndrome with a novel mutation in the BCOR gene.

  11. Decay of isolated surface features driven by the Gibbs-Thomson effect in analytic model and simulation

    OpenAIRE

    McLean, James G.; Krishnamachari, B.; Peale, D. R.; Chason, E.; Sethna, James P.; Cooper, B. H.

    1996-01-01

    A theory based on the thermodynamic Gibbs-Thomson relation is presented which provides the framework for understanding the time evolution of isolated nanoscale features (i.e., islands and pits) on surfaces. Two limiting cases are predicted, in which either diffusion or interface transfer is the limiting process. These cases correspond to similar regimes considered in previous works addressing the Ostwald ripening of ensembles of features. A third possible limiting case is noted for the specia...

  12. Acoustic emission-based in-process monitoring of surface generation in robot-assisted polishing

    DEFF Research Database (Denmark)

    Pilny, Lukas; Bissacco, Giuliano; De Chiffre, Leonardo

    2016-01-01

    The applicability of acoustic emission (AE) measurements for in-process monitoring of surface generation in the robot-assisted polishing (RAP) was investigated. Surface roughness measurements require interruption of the process, proper surface cleaning and measurements that sometimes necessitate...... removal of the part from the machine tool. In this study, stabilisation of surface roughness during polishing rotational symmetric surfaces by the RAP process was monitored by AE measurements. An AE sensor was placed on a polishing arm in direct contact with a bonded abrasive polishing tool...

  13. Erosion resistant anti-ice surfaces generated by ultra short laser pulses

    NARCIS (Netherlands)

    Del Cerro, D.A.; Römer, G.R.B.E.; Huis in't Veld, A.J.

    2010-01-01

    Wetting properties of a wide range of materials can be modified by accurate laser micromachining with ultra short laser pulses. Controlling the surface topography in a micro and sub-micrometer scale allows the generation of water-repellent surfaces, which remain dry and prevent ice accumulation

  14. Erosion resistant anti-ice surfaces generated by ultra short laser pulses

    NARCIS (Netherlands)

    Del Cerro, D.A.; Römer, G.R.B.E.; Huis in't Veld, A.J.

    2010-01-01

    Wetting properties of a wide range of materials can be modified by accurate laser micromachining with ultra short laser pulses. Controlling the surface topography in a micro and sub-micrometer scale allows the generation of water-repellent surfaces, which remain dry and prevent ice accumulation unde

  15. Giant enhancement of sum-frequency generation upon excitation of a surface plasmon-polariton

    NARCIS (Netherlands)

    Alieva, E. V.; Petrov, Y. E.; Yakovlev, V. A.; Eliel, E. R.; van der Ham, E. W. M.; Vrehen, Q. H. F.; van der Meer, A. F. G.; Sychugov, V. A.

    1997-01-01

    The generation of the sum frequency of visible (0.5235 mu m) and IP (10 mu m) radiation on smooth and corrugated silver surfaces is investigated. The sum-frequency signal obtained with a visible-range surface plasmon-polariton excited on a corrugated silver-air interface is found to be more than

  16. New subsea X tree generation brings innovative features providing efficiency for ultra deep waters

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Gustavo Bellot de Almeida; Labes, Alan Zaragoza [FMC Technologies, Houston, TX (United States)

    2008-07-01

    The EVDT has been developed for global applications. Based upon the widely field proven 10 K Vertical Tree and 15 K HPHT Tree, the system has incorporated the latest technological advancements. The Tubing Hanger System and installation tooling are available up to a 7 inch bore for 10,000 psi applications and a 5 inch bore for 15,000 psi applications. The Tubing Hanger can be installed using a Tubing Head when flexibility for sequencing of events is required during offshore installations. Or it can simply land into the wellhead, eliminating the Tubing Head. This allows for a more efficient installation when completion and drilling operations are conducted without retrieving the Sub sea Blow Out Preventer (BOP) and Riser. The EVDT incorporates a retrievable Flow Module downstream of the wing valve that can be configured to project specific variances such as production, gas injection and water injection service. The Flow Module can also be configured to include Multi-Phase Flow Meters, sensors, and gauges. This allows an upgrade sub sea without having to pull and re-run the entire Tree system. These features allowed the system to hit the mark regarding what the industry needs today and also allowed to accommodate technologies that will arise in the years to come. (author)

  17. Multi-Input Converter with MPPT Feature for Wind-PV Power Generation System

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen

    2013-01-01

    Full Text Available A multi-input converter (MIC to process wind-PV power is proposed, designed, analyzed, simulated, and implemented. The MIC cannot only process solar energy but deal with wind power, of which structure is derived from forward-type DC/DC converter to step-down/up voltage for charger systems, DC distribution applications, or grid connection. The MIC comprises an upper modified double-ended forward, a lower modified double-ended forward, a common output inductor, and a DSP-based system controller. The two modified double-ended forwards can operate individually or simultaneously so as to accommodate the variation of the hybrid renewable energy under different atmospheric conditions. While the MIC operates at interleaving mode, better performance can be achieved and volume also is reduced. The proposed MIC is capable of recycling the energy stored in the leakage inductance and obtaining high step-up output voltage. In order to draw maximum power from wind turbine and PV panel, perturb-and-observe method is adopted to achieve maximum power point tracking (MPPT feature. The MIC is constructed, analyzed, simulated, and tested. Simulations and hardware measurements have demonstrated the feasibility and functionality of the proposed multi-input converter.

  18. Decay of isolated surface features driven by the Gibbs-Thomson effect in an analytic model and a simulation

    Energy Technology Data Exchange (ETDEWEB)

    McLean, J.G.; Krishnamachari, B.; Peale, D.R. [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853-2501 (United States); Chason, E. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Sethna, J.P.; Cooper, B.H. [Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853-2501 (United States)

    1997-01-01

    A theory based on the thermodynamic Gibbs-Thomson relation is presented that provides the framework for understanding the time evolution of isolated nanoscale features (i.e., islands and pits) on surfaces. Two limiting cases are predicted, in which either diffusion or interface transfer is the limiting process. These cases correspond to similar regimes considered in previous works addressing the Ostwald ripening of ensembles of features. A third possible limiting case is noted for the special geometry of {open_quotes}stacked{close_quotes} islands. In these limiting cases, isolated features are predicted to decay in size with a power-law scaling in time: A{proportional_to}(t{sub 0}{minus}t){sup n}, where A is the area of the feature, t{sub 0} is the time at which the feature disappears, and n=2/3 or 1. The constant of proportionality is related to parameters describing both the kinetic and equilibrium properties of the surface. A continuous-time Monte Carlo simulation is used to test the application of this theory to generic surfaces with atomic scale features. A method is described to obtain macroscopic kinetic parameters describing interfaces in such simulations. Simulation and analytic theory are compared directly, using measurements of the simulation to determine the constants of the analytic theory. Agreement between the two is very good over a range of surface parameters, suggesting that the analytic theory properly captures the necessary physics. It is anticipated that the simulation will be useful in modeling complex surface geometries often seen in experiments on physical surfaces, for which application of the analytic model is not straightforward. {copyright} {ital 1997} {ital The American Physical Society}

  19. Decay of isolated surface features driven by the Gibbs-Thomson effect in an analytic model and a simulation

    Science.gov (United States)

    McLean, James G.; Krishnamachari, B.; Peale, D. R.; Chason, E.; Sethna, James P.; Cooper, B. H.

    1997-01-01

    A theory based on the thermodynamic Gibbs-Thomson relation is presented that provides the framework for understanding the time evolution of isolated nanoscale features (i.e., islands and pits) on surfaces. Two limiting cases are predicted, in which either diffusion or interface transfer is the limiting process. These cases correspond to similar regimes considered in previous works addressing the Ostwald ripening of ensembles of features. A third possible limiting case is noted for the special geometry of ``stacked'' islands. In these limiting cases, isolated features are predicted to decay in size with a power-law scaling in time: A~(t0-t)n, where A is the area of the feature, t0 is the time at which the feature disappears, and n=2/3 or 1. The constant of proportionality is related to parameters describing both the kinetic and equilibrium properties of the surface. A continuous-time Monte Carlo simulation is used to test the application of this theory to generic surfaces with atomic scale features. A method is described to obtain macroscopic kinetic parameters describing interfaces in such simulations. Simulation and analytic theory are compared directly, using measurements of the simulation to determine the constants of the analytic theory. Agreement between the two is very good over a range of surface parameters, suggesting that the analytic theory properly captures the necessary physics. It is anticipated that the simulation will be useful in modeling complex surface geometries often seen in experiments on physical surfaces, for which application of the analytic model is not straightforward.

  20. Crossing the dividing surface of transition state theory. IV. Dynamical regularity and dimensionality reduction as key features of reactive trajectories

    Science.gov (United States)

    Lorquet, J. C.

    2017-04-01

    energies, these characteristics persist, but to a lesser degree. Recrossings of the dividing surface then become much more frequent and the phase space volumes of initial conditions that generate recrossing-free trajectories decrease. Altogether, one ends up with an additional illustration of the concept of reactive cylinder (or conduit) in phase space that reactive trajectories must follow. Reactivity is associated with dynamical regularity and dimensionality reduction, whatever the shape of the potential energy surface, no matter how strong its anharmonicity, and whatever the curvature of its reaction path. Both simplifying features persist during the entire reactive process, up to complete separation of fragments. The ergodicity assumption commonly assumed in statistical theories is inappropriate for reactive trajectories.

  1. OUT-OF-FOCUS REGION SEGMENTATION OF 2D SURFACE IMAGES WITH THE USE OF TEXTURE FEATURES

    Directory of Open Access Journals (Sweden)

    K. Anding

    2015-09-01

    Full Text Available A segmentation method of out-of-focus image regions for processed metal surfaces, based on focus textural features is proposed. Such regions contain small amount of useful information. The object of study is a metal surface, which has a cone shape. Some regions of images are blurred because the depth of field of industrial cameras is limited. Automatic removal of out-of-focus regions in such images is one of the possible solutions to this problem. Focus texture features were used to calculate characteristics that describe the sharpness of particular image area. Such features are used in autofocus systems of microscopes and cameras, and their application for segmentation of out-of-focus regions of images is unusual. Thirty-four textural features were tested on a set of metal surface images with out-of-focus regions. The most useful features, usable for segmentation of an image more accurately, are an average grey level and spatial frequency. Proposed segmentation method of out-of-focus image regions for metal surfaces can be successfully applied for evaluation of processing quality of materials with the use of industrial cameras. The method has simple implementation and high calculating speed.

  2. Generation of New Genotypic and Phenotypic Features in Artificial and Natural Yeast Hybrids

    Directory of Open Access Journals (Sweden)

    Walter P. Pfliegler

    2014-01-01

    Full Text Available Evolution and genome stabilization have mostly been studied on the Saccharomyces hybrids isolated from natural and alcoholic fermentation environments. Genetic and phenotypic properties have usually been compared to the laboratory and reference strains, as the true ancestors of the natural hybrid yeasts are unknown. In this way the exact impact of different parental fractions on the genome organization or metabolic activity of the hybrid yeasts is difficult to resolve completely. In the present work the evolution of geno- and phenotypic properties is studied in the interspecies hybrids created by the cross-breeding of S. cerevisiae with S. uvarum or S. kudriavzevii auxotrophic mutants. We hypothesized that the extent of genomic alterations in S. cerevisiae × S. uvarum and S. cerevisiae × S. kudriavzevii should affect the physiology of their F1 offspring in different ways. Our results, obtained by amplified fragment length polymorphism (AFLP genotyping and karyotyping analyses, showed that both subgenomes of the S. cerevisiae x S. uvarum and of S. cerevisiae × S. kudriavzevii hybrids experienced various modifications. However, the S. cerevisiae × S. kudriavzevii F1 hybrids underwent more severe genomic alterations than the S. cerevisiae × S. uvarum ones. Generation of the new genotypes also influenced the physiological performances of the hybrids and the occurrence of novel phenotypes. Significant differences in carbohydrate utilization and distinct growth dynamics at increasing concentrations of sodium chloride, urea and miconazole were observed within and between the S. cerevisiae × S. uvarum and S. cerevisiae × S. kudriavzevii hybrids. Parental strains also demonstrated different contributions to the final metabolic outcomes of the hybrid yeasts. A comparison of the genotypic properties of the artificial hybrids with several hybrid isolates from the wine-related environments and wastewater demonstrated a greater genetic variability of

  3. Sugar-fiber Imprinting to Generate Microgrooves on Polymeric Film Surfaces for Contact Guidance of Cells

    Institute of Scientific and Technical Information of China (English)

    屈泽华; 丁建东

    2012-01-01

    Anisotropic surface topography is known to induce the contact guidance of cells, and facile and biocompatible approaches of the physical modification of the pertinent matrix surfaces are thus meaningful for biomaterials. Herein, we put forward a sugar-fiber imprinting technique to generate microgrooves on hydrophobic polymers demonstrated by the poly(lactic-eo-glycolic acid) (PLGA) films. Microgrooves were conveniently generated after removing sugar fibers simply by water. The resulting locally anisotropic microgrooves were confirmed to elongate the cells cultured on the surface.

  4. A topological study of gravity free-surface waves generated by bluff bodies using the method of steepest descents.

    Science.gov (United States)

    Trinh, Philippe H

    2016-07-01

    The standard analytical approach for studying steady gravity free-surface waves generated by a moving body often relies upon a linearization of the physical geometry, where the body is considered asymptotically small in one or several of its dimensions. In this paper, a methodology that avoids any such geometrical simplification is presented for the case of steady-state flows at low speeds. The approach is made possible through a reduction of the water-wave equations to a complex-valued integral equation that can be studied using the method of steepest descents. The main result is a theory that establishes a correspondence between different bluff-bodied free-surface flow configurations, with the topology of the Riemann surface formed by the steepest descent paths. Then, when a geometrical feature of the body is modified, a corresponding change to the Riemann surface is observed, and the resultant effects to the water waves can be derived. This visual procedure is demonstrated for the case of two-dimensional free-surface flow past a surface-piercing ship and over an angled step in a channel.

  5. A topological study of gravity free-surface waves generated by bluff bodies using the method of steepest descents

    Science.gov (United States)

    Trinh, Philippe H.

    2016-07-01

    The standard analytical approach for studying steady gravity free-surface waves generated by a moving body often relies upon a linearization of the physical geometry, where the body is considered asymptotically small in one or several of its dimensions. In this paper, a methodology that avoids any such geometrical simplification is presented for the case of steady-state flows at low speeds. The approach is made possible through a reduction of the water-wave equations to a complex-valued integral equation that can be studied using the method of steepest descents. The main result is a theory that establishes a correspondence between different bluff-bodied free-surface flow configurations, with the topology of the Riemann surface formed by the steepest descent paths. Then, when a geometrical feature of the body is modified, a corresponding change to the Riemann surface is observed, and the resultant effects to the water waves can be derived. This visual procedure is demonstrated for the case of two-dimensional free-surface flow past a surface-piercing ship and over an angled step in a channel.

  6. Peculiar features of composition of carbonyl components of surface lipids in aquatic plants

    OpenAIRE

    І. О. Alexeevs’ka; V. M. Shepelenko; N. I. Shtemenko

    2006-01-01

    Carbonyl components content of aquatic plants’ surface lipids has been studied. High concentration of oxo-compounds in surface lipids of aquatic plants has been shown. It could reach 60 % of total value. Sufficient heterogeneity of surface lipids has been demonstrated. Unsaturated character of oxo-components in aquatic plants’ surface lipids has been assumed in the present work.

  7. Uav Aerial Survey: Accuracy Estimation for Automatically Generated Dense Digital Surface Model and Orthothoto Plan

    Science.gov (United States)

    Altyntsev, M. A.; Arbuzov, S. A.; Popov, R. A.; Tsoi, G. V.; Gromov, M. O.

    2016-06-01

    A dense digital surface model is one of the products generated by using UAV aerial survey data. Today more and more specialized software are supplied with modules for generating such kind of models. The procedure for dense digital model generation can be completely or partly automated. Due to the lack of reliable criterion of accuracy estimation it is rather complicated to judge the generation validity of such models. One of such criterion can be mobile laser scanning data as a source for the detailed accuracy estimation of the dense digital surface model generation. These data may be also used to estimate the accuracy of digital orthophoto plans created by using UAV aerial survey data. The results of accuracy estimation for both kinds of products are presented in the paper.

  8. Surface charge properties of red mud particles generated from Chinese diaspore bauxite

    Institute of Scientific and Technical Information of China (English)

    ZHANG Kun-yu; HU Hui-ping; ZHANG Li-juan; CHEN Qi-yuan

    2008-01-01

    Acid/basic potentiometric titration can be used to quantify the red mud surface charge properties. The amount of surface active -OH groups and surface charge density on the red mud particles generated from Chinese diaspore bauxite were evaluated from the acid/basic potentiometric titration data in 0.1 mol/L or 0.5 molL NaCI solution. The results show that the adsorption of sodium polyacrylate(SPA) on the red mud surface causes the increase of the surface active -OH groups, which makes the point of zero charge(PZC) shift to a lower pH value. However, the adsorption of polyacrylamide(PAM) causes little change. As the concentration of NaCl solution increases, the surface charge becomes more positive in acidic solution and more negative in alkaline solution, which can be attributed to the presence of a porous surface gel coating on the red mud particles.

  9. Osteoblasts generate an osteogenic microenvironment when grown on surfaces with rough microtopographies

    Directory of Open Access Journals (Sweden)

    Boyan B. D.

    2003-10-01

    Full Text Available Osteoblasts respond to microarchitectural features of their substrate. On smooth surfaces (tissue culture plastic, tissue culture glass, and titanium, the cells attach and proliferate but they exhibit relatively low expression of differentiation markers in monolayer cultures, even when confluent. When grown on microrough Ti surfaces with an average roughness (Ra of 4-7 µm, proliferation is reduced but differentiation is enhanced and in some cases, is synergistic with the effects of surface microtopography. In addition, cells on microrough Ti substrates form hydroxyapatite in a manner that is more typical of bone than do cells cultured on smooth surfaces. Osteoblasts also respond to growth factors and cytokines in a surface-dependent manner. On rougher surfaces, the effects of regulatory factors like 1alpha,25(OH2D3 or 17beta-estradiol are enhanced. The response to the surface is mediated by integrins, which signal to the cell through many of the same mechanisms used by growth factors and hormones. Studies using PEG-modified surfaces indicate that increased differentiation may be related to altered attachment to the surface. When osteoblasts are grown on surfaces with chemistries or microarchitectures that reduce cell attachment and proliferation, and enhance differentiation, the cells tend to increase production of factors like TGF-beta1 that promote osteogenesis while decreasing osteoclastic activity. Thus, on microrough Ti surface, osteoblasts create a microenvironment conducive to new bone formation.

  10. Remote laser generation of narrow-band surface waves through optical fibers.

    Science.gov (United States)

    Di Scalea, F L; Berndt, T P; Spicer, J B; Djordjevic, B B

    1999-01-01

    This paper demonstrates the use of a fiberoptic bundle for flexible, compact, remote, and noncontact laser generation of surface ultrasonic waves in materials. The bundle is able to deliver Nd:YAG pulsed light with a 60% delivery efficiency up to an average energy of 55 mJ/pulse for a pulse duration on the order of 10 ns and a pulse repetition rate of 20 Hz without signs of fiber damage. Details of the bundle construction and surface preparation are given, and pulsed light delivery tests performed with single tapered fibers are discussed. The high-power light delivery capabilities of the bundle are demonstrated for the generation of narrow-band surface waves in a Carbon/PEEK composite laminate by a spatial modulation technique that employs a periodic transmission mask. Single laser pulse ultrasonic tonebursts are clearly detectable using a small aperture piezoelectric transducer while ensuring thermoelastic generation conditions. The theory of narrow-band generation of surface acoustic waves is improved by accounting for the strength nonuniformity of the illumination sources. In addition, the effect of the number of illumination sources on the bandwidth of the generated surface wave is assessed experimentally, and excellent agreement is shown with the theoretical results predicted by the improved model.

  11. Machining Feature Recognition Based on Surface Clustering%基于表面聚类优化的加工特征识别方法

    Institute of Scientific and Technical Information of China (English)

    汤岑书; 褚学宁; 孙习武; 苏於梁

    2009-01-01

    To realize the effective integration of CAD and CAPP system, an approach of machining feature recognition was proposed based on the generation and clustering of surface machining methods. Three kinds of information models, such as manufacturing resource, machined surface and machining method were built. A concept of cutting mode was proposed and used for generating the machining methods of part surfaces. Aiming at minimizing the number of tool type and the number of setups used, an optimal model for surface clustering was established to select the best machining method for every surface. Surfaces which can be simultaneously machined by a common type of tool in the same setup were then recognized as a machining feature. Finally, an example part was used to test the validity and effectiveness of the approach proposed, and the final results illustrate that the approach can effectively solve some problems such as the recognition of intersecting features which are difficult to traditional feature recognition approaches.%为了实现计算机辅助设计与计算机辅助工艺设计系统的有效集成,提出了以表面加工方法生成和聚类优化为基础的加工特征识别新方法.基于加工资源、加工表面和加工方法3类信息模型,引出了切削模式概念和表面加工方法生成的原理.以刀具种类数和零件装夹次数最少为目标,建立了表面聚类优化模型,为加工表面选择最优加工方法,并把可用同类刀具、在同一装夹下连续加工的一组表面聚为一个加工特征.通过实例测试,验证了该方法的正确性和有效性.

  12. The Benefit of Surface Uniformity for Encoding Boundary Features in Visual Working Memory

    Science.gov (United States)

    Kim, Sung-Ho; Kim, Jung-Oh

    2011-01-01

    Using a change detection paradigm, the present study examined an object-based encoding benefit in visual working memory (VWM) for two boundary features (two orientations in Experiments 1-2 and two shapes in Experiments 3-4) assigned to a single object. Participants remembered more boundary features when they were conjoined into a single object of…

  13. Internal Physical Features of a Land Surface Model Employing a Tangent Linear Model

    Science.gov (United States)

    Yang, Runhua; Cohn, Stephen E.; daSilva, Arlindo; Joiner, Joanna; Houser, Paul R.

    1997-01-01

    The Earth's land surface, including its biomass, is an integral part of the Earth's weather and climate system. Land surface heterogeneity, such as the type and amount of vegetative covering., has a profound effect on local weather variability and therefore on regional variations of the global climate. Surface conditions affect local weather and climate through a number of mechanisms. First, they determine the re-distribution of the net radiative energy received at the surface, through the atmosphere, from the sun. A certain fraction of this energy increases the surface ground temperature, another warms the near-surface atmosphere, and the rest evaporates surface water, which in turn creates clouds and causes precipitation. Second, they determine how much rainfall and snowmelt can be stored in the soil and how much instead runs off into waterways. Finally, surface conditions influence the near-surface concentration and distribution of greenhouse gases such as carbon dioxide. The processes through which these mechanisms interact with the atmosphere can be modeled mathematically, to within some degree of uncertainty, on the basis of underlying physical principles. Such a land surface model provides predictive capability for surface variables including ground temperature, surface humidity, and soil moisture and temperature. This information is important for agriculture and industry, as well as for addressing fundamental scientific questions concerning global and local climate change. In this study we apply a methodology known as tangent linear modeling to help us understand more deeply, the behavior of the Mosaic land surface model, a model that has been developed over the past several years at NASA/GSFC. This methodology allows us to examine, directly and quantitatively, the dependence of prediction errors in land surface variables upon different vegetation conditions. The work also highlights the importance of accurate soil moisture information. Although surface

  14. How do features of dressage arenas influence training surface properties which are potentially associated with lameness?

    Science.gov (United States)

    Murray, Rachel C; Walters, Juli; Snart, Hannah; Dyson, Sue; Parkin, Tim

    2010-11-01

    Results from a previous study indicated that there are specific arena surface characteristics that are associated with an increased likelihood of lameness in dressage horses. It is important to understand what modifiable arena factors lead to these detrimental surface characteristics. The aim of this study was to describe the use of training surfaces and arenas for United Kingdom dressage horses and to investigate any relationships between arena/surface variables and detrimental surface characteristics. Data from a questionnaire returned by 22.5% of all 11,363 registered members of British Dressage were used for the study. Univariate and multivariable logistic regression models were developed with each of the previously identified surface characteristics as dependent variables. Respondents reported that the majority of arenas were privately owned, sized 20 × 40 m and had a sand and rubber surface. The results indicated that wax-coated and sand and rubber surfaces were associated with less detrimental surface properties than sand, sand and PVC, woodchips or grass. Woodchips were most strongly associated with the detrimental characteristic of slipping, and sand with tripping. The findings indicated that any arena surface should have a base, with limestone the recommended surface, and that crushed concrete was best avoided. This information supported previous studies in racehorses that indicated that surface maintenance is essential, especially when many horses are using an arena daily. Problems were less likely if an arena was privately owned. Copyright © 2010. Published by Elsevier Ltd.

  15. Salient features of otoacoustic emissions are common across tetrapod groups and suggest shared properties of generation mechanisms.

    Science.gov (United States)

    Bergevin, Christopher; Manley, Geoffrey A; Köppl, Christine

    2015-03-17

    Otoacoustic emissions (OAEs) are faint sounds generated by healthy inner ears that provide a window into the study of auditory mechanics. All vertebrate classes exhibit OAEs to varying degrees, yet the biophysical origins are still not well understood. Here, we analyzed both spontaneous (SOAE) and stimulus-frequency (SFOAE) otoacoustic emissions from a bird (barn owl, Tyto alba) and a lizard (green anole, Anolis carolinensis). These species possess highly disparate macromorphologies of the inner ear relative to each other and to mammals, thereby allowing for novel insights into the biomechanical mechanisms underlying OAE generation. All ears exhibited robust OAE activity, and our chief observation was that SFOAE phase accumulation between adjacent SOAE peak frequencies clustered about an integral number of cycles. Being highly similar to published results from human ears, we argue that these data indicate a common underlying generator mechanism of OAEs across all vertebrates, despite the absence of morphological features thought essential to mammalian cochlear mechanics. We suggest that otoacoustic emissions originate from phase coherence in a system of coupled oscillators, which is consistent with the notion of "coherent reflection" but does not explicitly require a mammalian-type traveling wave. Furthermore, comparison between SFOAE delays and auditory nerve fiber responses for the barn owl strengthens the notion that most OAE delay can be attributed to tuning.

  16. The complementary graphical method used for profiling side mill for generation of helical surface

    Science.gov (United States)

    Baroiu, N.; Berbinschi, S.; Teodor, V. G.; Susac, F.; Oancea, N.

    2017-08-01

    This paper presents a method developed in CATIA design environment, for profiling tools bounded by revolution peripheral surfaces — side mill tool. The graphical method is based on a complementary theorem of surface enveloping. They are presented specific algorithms and an example for profiling generating tools of helical flutes of compressors rotors with three lobes. The obtained results with graphical method are compared with those obtained by a classical method — the Nikolaev theorem. The graphical method is very intuitive and, at the same time, very rigorous. It is characterized by the simplicity of application and avoids the ambiguity case of solutions, which are frequently met in numerical methods, as profiles overlapping, generating of revolving surfaces or rotating a spatial curve around the tool’s axis. Other advantage of using graphical methods is that CNC machines tools, used for generating profiled tools, allows importing the files, which directly result from graphical modeling.

  17. Use of the discriminant Fourier-derived cepstrum with feature-level post-processing for surface electromyographic signal classification.

    Science.gov (United States)

    Chen, Xinpu; Zhu, Xiangyang; Zhang, Dingguo

    2009-12-01

    Myoelectrical pattern classification is a crucial part in multi-functional prosthesis control. This paper investigates a discriminant Fourier-derived cepstrum (DFC) and feature-level post-processing (FLPP) to discriminate hand and wrist motions using the surface electromyographic signal. The Fourier-derived cepstrum takes advantage of the Fourier magnitude or sub-band power energy of signals directly and provides flexible use of spectral information changing with different motions. Appropriate cepstral coefficients are selected by a proposed separability criterion to construct DFC features. For the post-processing, FLPP which combines features from several analysis windows is used to improve the feature performance further. In this work, two classifiers (a linear discriminant classifier and quadratic discriminant classifier) without hyper-parameter optimization are employed to simplify the training procedure and avoid the possible bias of feature evaluation. Experimental results of the 11-motion problem show that the proposed DFC feature outperforms traditional features such as time-domain statistics and autoregressive-derived cepstrum in terms of the classification accuracy, and it is a promising method for the multi-functionality and high-accuracy control of myoelectric prostheses.

  18. Surface deformations and wave generation by wind blowing over a viscous liquid

    CERN Document Server

    Paquier, Anna; Rabaud, Marc

    2015-01-01

    We investigate experimentally the early stage of the generation of waves by a turbulent wind at the surface of a viscous liquid. The spatio-temporal structure of the surface deformation is analyzed by the optical method Free Surface Synthetic Schlieren, which allows for time-resolved measurements with a micrometric accuracy. Because of the high viscosity of the liquid, the flow induced by the turbulent wind in the liquid remains laminar, with weak surface drift velocity. Two regimes of deformation of the liquid-air interface are identified. In the first regime, at low wind speed, the surface is dominated by rapidly propagating disorganized wrinkles, elongated in the streamwise direction, which can be interpreted as the surface response to the pressure fluctuations advected by the turbulent airflow. The amplitude of these deformations increases approximately linearly with wind velocity and are essentially independent of the fetch (distance along the channel). Above a threshold in wind speed, the perturbations ...

  19. Laterally emitted surface second harmonic generation in a single ZnTe nanowire

    CERN Document Server

    Liu, Weiwei; Liu, Zhe; Shen, Guozhen; Lu, Peixiang

    2012-01-01

    We report a direct observation on the unique laterally emitted surface second harmonic generation (SHG) in a single ZnTe nanowire. The highly directional surface SHG signal that polarizes along the direction vertical to the nanowire growth axis, is significantly larger than the bulk SHG contribution, indicating a high efficiency of surface SHG. Two strong SHG peaks are observed on both sides of the nanowire surfaces in the far-field scanning images, which is further supported by FDTD simulations, demonstrating that the unique laterally emitted signal is ascribed to surface SHG in the ZnTe nanowire. The surface SHG in a single ZnTe nanowire with unique lateral emission and high conversion efficiency shows great potential applications in short-wavelength nanolasers, nonlinear microscopy and polarization dependent photonic integrating.

  20. Superhydrophilic TiO{sub 2} surfaces generated by reactive oxygen treatment

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, Nobuyuki; Fujita, Daisuke [Global Research Center for Environment and Energy based on Nanomaterials Science (GREEN), National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Global Research Center for Environment and Energy based on Nanomaterials Science (GREEN), National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan) and Advanced Nanocharacterization Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

    2012-09-15

    The authors show that superhydrophilic TiO{sub 2} can be obtained without irradiation of the surface with ultraviolet (UV) light and concomitant excitation of electron-hole pairs. The authors demonstrate that the treatment of TiO{sub 2} surfaces with reactive oxygen species generated by air plasma removes the surface organic contaminants, leading to almost 0 Degree-Sign contact-angle wetting of the surface. The superhydrophilicity can be explained by the positive spreading coefficient calculated using the effective surface tensions. Our results point toward UV-light irradiation as an indirect cause of the superhydrophilicity of TiO{sub 2} and support the hypothesis that this property arises from a self-cleaning effect based on the photo-oxidation and decomposition of organic contaminants at the surface.

  1. Solvent-surface interactions control the phase structure in laser-generated iron-gold core-shell nanoparticles

    Science.gov (United States)

    Wagener, Philipp; Jakobi, Jurij; Rehbock, Christoph; Chakravadhanula, Venkata Sai Kiran; Thede, Claas; Wiedwald, Ulf; Bartsch, Mathias; Kienle, Lorenz; Barcikowski, Stephan

    2016-03-01

    This work highlights a strategy for the one-step synthesis of FeAu nanoparticles by the pulsed laser ablation of alloy targets in the presence of different solvents. This method allows particle generation without the use of additional chemicals; hence, solvent-metal interactions could be studied without cross effects from organic surface ligands. A detailed analysis of generated particles via transmission electron microscopy in combination with EDX elemental mapping could conclusively verify that the nature of the used solvent governs the internal phase structure of the formed nanoparticles. In the presence of acetone or methyl methacrylate, a gold shell covering a non-oxidized iron core was formed, whereas in aqueous media, an Au core with an Fe3O4 shell was generated. This core-shell morphology was the predominant species found in >90% of the examined nanoparticles. These findings indicate that fundamental chemical interactions between the nanoparticle surface and the solvent significantly contribute to phase segregation and elemental distribution in FeAu nanoparticles. A consecutive analysis of resulting Fe@Au core-shell nanoparticles revealed outstanding oxidation resistance and fair magnetic and optical properties. In particular, the combination of these features with high stability magnetism and plasmonics may create new opportunities for this hybrid material in imaging applications.

  2. Generation of unsteady waves by concentrated disturbances in an inviscid fluid with an inertial surface

    Institute of Scientific and Technical Information of China (English)

    D. Q. Lu; S. Q. Dai

    2008-01-01

    The surface waves generated by unsteady concentrated disturbances in an initially quiescent fluid of infinite depth with an inertial surface are analytically investigated for two- and three-dimensional cases. The fluid is assumed to be inviscid, incompressible and homogenous. The inertial surface represents the effect of a thin uniform distribution of non-interacting floating matter. Four types of unsteady concentrated disturbances and two kinds of initial values are considered, namely an instantaneous/oscillating mass source immersed in the fluid, an instantaneous/oscillating impulse on the surface, an initial impulse on the surface of the fluid, and an initial displacement of the surface. The linearized initial-boundary-value problem is formulated within the framework of potential flow. The solutions in integral form for the surface elevation are obtained by means of a joint Laplace-Fourier transform. The asymptotic representations of the wave motion for large time with a fixed distance-to-time ratio are derived by using the method of stationary phase. The effect of the presence of an inertial surface on the wave motion is analyzed. It is found that the wavelengths of the transient dispersive waves increase while those of the steady-state progressive waves decrease. All the wave amplitudes decrease in comparison with those of conventional free-surface waves. The explicit expressions for the free-surface gravity waves can readily be recovered by the present results as the inertial surface disappears.

  3. Unidirectional generation of surface plasmon polaritons by a single right-angled trapezoid metallic nanoslit

    Science.gov (United States)

    Yang, Xuefeng; Wang, Jun; Hann Lim, Xiao; Xu, Zhengji; Teng, Jinghua; Zhang, Dao Hua

    2017-02-01

    We report theoretical and experimental investigation on a single right-angled trapezoid metallic nanoslit for efficient unidirectional generation of surface plasmon polaritons (SPPs) under normal incidence. The propagated SPPs intensity ratio in two directions is sensitive to the taper angle and metal thickness. Significant intensity ratio at the same propagation distances from the respective slit edges in opposite directions is demonstrated. We believe that the proposed compact unidirectional SPPs generator has high potential for applications in nanolithography and photonic integration.

  4. Feasibility Analysis of Liquefying Oxygen Generated from Water Electrolysis Units on Lunar Surface

    Science.gov (United States)

    Jeng, Frank F.

    2009-01-01

    Concepts for liquefying oxygen (O2) generated from water electrolysis subsystems on the Lunar surface were explored. Concepts for O2 liquefaction units capable of generating 1.38 lb/hr (0.63 kg/hr) liquid oxygen (LOX) were developed. Heat and mass balance calculations for the liquefaction concepts were conducted. Stream properties, duties of radiators, heat exchangers and compressors for the selected concepts were calculated and compared.

  5. Surface plasmon polariton excitation by second harmonic generation in single organic nanofibers.

    Science.gov (United States)

    Simesen, Paw; Søndergaard, Thomas; Skovsen, Esben; Fiutowski, Jacek; Rubahn, Horst-Günter; Bozhevolnyi, Sergey I; Pedersen, Kjeld

    2015-06-15

    Coherent local excitation of surface plasmon polaritons (SPPs) by second-harmonic generation (SHG) in individual aligned crystalline organic functionalized para-phenylene nanofibers deposited on a thin silver film is demonstrated. The SH-SPP generation is considered theoretically and investigated experimentally with angular-resolved leakage radiation spectroscopy for normal incidence of the excitation beam. Both measurements and simulations show asymmetric excitation of left- and right-propagating SH-SPPs, which is explained as an effect of fiber molecules being oriented at an angle relative to the silver film surface.

  6. Fine-scale features on the sea surface in SAR satellite imagery – Part 1: Simultaneous in-situ measurements

    Directory of Open Access Journals (Sweden)

    S. Brusch

    2012-09-01

    Full Text Available This work is aimed at identifying the origin of fine-scale features on the sea surface in synthetic aperture radar (SAR imagery with the help of in-situ measurements as well as numerical models (presented in a companion paper. We are interested in natural and artificial features starting from the horizontal scale of the upper ocean mixed layer, around 30–50 m. These features are often associated with three-dimensional upper ocean dynamics. We have conducted a number of studies involving in-situ observations in the Straits of Florida during SAR satellite overpass. The data include examples of sharp frontal interfaces, wakes of surface ships, internal wave signatures, as well as slicks of artificial and natural origin. Atmospheric processes, such as squall lines and rain cells, produced prominent signatures on the sea surface. This data has allowed us to test an approach for distinguishing between natural and artificial features and atmospheric influences in SAR images that is based on a co-polarized phase difference filter.

  7. Features of electromagnetic waves in a complex plasma due to surface plasmon resonances on macroparticles

    CERN Document Server

    Vladimirov, S V

    2015-01-01

    The dielectric properties of complex plasma containing either metal or dielectric spherical inclusions (macroparticles, dust) are investigated. We focus on surface plasmon resonances on the macroparticle surfaces and their effect on electromagnetic wave propagation. It is demonstrated that the presence of surface plasmon oscillations significantly modifies plasma electromagnetic properties by resonances and cutoffs in the effective permittivity. This leads to related branches of electromagnetic waves and to the wave band gaps. The results are discussed in the context of dusty plasma experiments.

  8. Platelet-rich fibrin (PRF): a second-generation platelet concentrate. Part II: platelet-related biologic features.

    Science.gov (United States)

    Dohan, David M; Choukroun, Joseph; Diss, Antoine; Dohan, Steve L; Dohan, Anthony J J; Mouhyi, Jaafar; Gogly, Bruno

    2006-03-01

    Platelet-rich fibrin (PRF) belongs to a new generation of platelet concentrates, with simplified processing and without biochemical blood handling. In this second article, we investigate the platelet-associated features of this biomaterial. During PRF processing by centrifugation, platelets are activated and their massive degranulation implies a very significant cytokine release. Concentrated platelet-rich plasma platelet cytokines have already been quantified in many technologic configurations. To carry out a comparative study, we therefore undertook to quantify PDGF-BB, TGFbeta-1, and IGF-I within PPP (platelet-poor plasma) supernatant and PRF clot exudate serum. These initial analyses revealed that slow fibrin polymerization during PRF processing leads to the intrinsic incorporation of platelet cytokines and glycanic chains in the fibrin meshes. This result would imply that PRF, unlike the other platelet concentrates, would be able to progressively release cytokines during fibrin matrix remodeling; such a mechanism might explain the clinically observed healing properties of PRF.

  9. Near-Surface Crevasse Detection in Ice Sheets using Feature-Based Machine Learning

    Science.gov (United States)

    Ray, L.; Walker, B.; Lever, J.; Arcone, S. A.

    2015-12-01

    In 2014, a team of Dartmouth, CRREL, and University of Maine researchers conducted the first of three annual ground-penetrating radar surveys of the McMurdo Shear Zone using robot-towed instruments. This survey provides over 100 transects of a 5.7 km x 5.0 km grid spanning the width of the shear zone at spacing of approximately 50 m. Transect direction was orthogonal to ice flow. Additionally, a dense 200 m x 200 m grid was surveyed at 10 m spacing in both the N-S and W-E directions. Radar settings provided 20 traces/sec, which combined with an average robot speed of 1.52 m/s, provides a trace every 7.6 cm. The robot towed two antenna units at 400 MHz and 200 MHz center frequencies, with the former penetrating to approximately 19 m. We establish boundaries for the shear zone over the region surveyed using the 400 MHz antenna data, and we geo-locate crevasses using feature-based machine learning classification of GPR traces into one of three classes - 1) firn, 2) distinct crevasses, and 3) less distinct or deeper features originating within the 19 m penetration depth. Distinct crevasses feature wide, hyperbolic reflections with strike angles of 35-40° to transect direction and clear voids. Less distinct or deeper features range from broad diffraction patterns with no clear void to overlapping diffractions extending tens of meters in width with or without a clear void. The classification is derived from statistical features of unprocessed traces and thus provides a computationally efficient means for eventual real-time classification of GPR traces. Feature-based classification is shown to be insensitive to artifacts related to rolling or pitching motion of the instrument sled and also provides a means of assessing crevasse width and depth. In subsequent years, we will use feature-based classification to estimate ice flow and evolution of individual crevasses.

  10. Second generation diffusion model of interacting gravity waves on the surface of deep fluid

    Directory of Open Access Journals (Sweden)

    A. Pushkarev

    2004-01-01

    Full Text Available We propose a second generation phenomenological model for nonlinear interaction of gravity waves on the surface of deep water. This model takes into account the effects of non-locality of the original Hasselmann diffusion equation still preserving important properties of the first generation model: physically consistent scaling, adherence to conservation laws and the existence of Kolmogorov-Zakharov solutions. Numerical comparison of both models with the original Hasselmann equation shows that the second generation models improves the angular distribution in the evolving wave energy spectrum.

  11. Clinical utility of a next generation sequencing panel assay for Marfan and Marfan-like syndromes featuring aortopathy.

    Science.gov (United States)

    Wooderchak-Donahue, Whitney; VanSant-Webb, Chad; Tvrdik, Tatiana; Plant, Parker; Lewis, Tracey; Stocks, Jennifer; Raney, Joshua A; Meyers, Lindsay; Berg, Alizabeth; Rope, Alan F; Yetman, Anji T; Bleyl, Steven B; Mesley, Rebecca; Bull, David A; Collins, R Thomas; Ojeda, Mayra Martinez; Roberts, Amy; Lacro, Ronald; Woerner, Audrey; Stoler, Joan; Bayrak-Toydemir, Pinar

    2015-08-01

    Aortopathy can be defined as aortic dilation, aneurysm, dissection, and tortuosity. Familial aortopathy may occur secondary to fibrillin-1 (FBN1) mutations in the setting of Marfan syndrome, or may occur as a result of other genetic defects with different, but occasionally overlapping, phenotypes. Because of the phenotypic overlap and genetic heterogeneity of disorders featuring aortopathy, we developed a next generation sequencing (NGS) assay and comparative genomic hybridization (CGH) array to detect mutations in 10 genes that cause thoracic aortic aneurysms (TAAs). Here, we report on the clinical and molecular findings in 175 individuals submitted for aortopathy panel testing at ARUP laboratories. Ten genes associated with heritable aortopathies were targeted using hybridization capture prior to sequencing. NGS results were analyzed, and variants were confirmed using Sanger sequencing. Array CGH was used to detect copy-number variation. Of 175 individuals, 18 had a pathogenic mutation and 32 had a variant of uncertain significance (VUS). Most pathogenic mutations (72%) were identified in FBN1. A novel large SMAD3 duplication and FBN1 deletion were identified. Over half who had TAAs or other aortic involvement tested negative for a mutation, suggesting that additional aortopathy genes exist. We anticipate that the clinical sensitivity of at least 10.3% will rise with VUS reclassification and as additional genes are identified and included in the panel. The aortopathy NGS panel aids in the timely molecular diagnosis of individuals with disorders featuring aortopathy and guides proper treatment.

  12. Multifunctional silicon surfaces: reaction of dichlorocarbene generated from Seyferth reagent with hydrogen-terminated silicon (111) surfaces.

    Science.gov (United States)

    Liu, Wenjun; Sharp, Ian D; Tilley, T Don

    2014-01-14

    Insertion of dichlorocarbene (:CCl2), generated by decomposition of the Seyferth reagent PhHgCCl2Br, into the Si-H bond of a tertiary silane to form a Si-CCl2H group is an efficient homogeneous, molecular transformation. A heterogeneous version of this reaction, between PhHgCCl2Br and a silicon (111) surface terminated by tertiary Si-H bonds, was studied using a combination of surface-sensitive infrared and X-ray photoelectron spectroscopies. The insertion of dichlorocarbene into surface Si-H bonds parallels the corresponding reaction of silanes in solution, to produce surface-bound dichloromethyl groups (Si-CCl2H) covering ∼25% of the silicon surface sites. A significant fraction of the remaining Si-H bonds on the surface was converted to Si-Cl/Br groups during the same reaction, with PhHgCCl2Br serving as a halogen atom source. The presence of two distinct environments for the chlorine atoms (Si-CCl2H and Si-Cl) and one type of bromine atom (Si-Br) was confirmed by Cl 2p, Br 3d, and C 1s X-ray photoelectron spectroscopy. The formation of reactive, halogen-terminated atop silicon sites was also verified by reaction with sodium azide or the Grignard reagent (CH3MgBr), to produce Si-N3 or Si-Me functionalities, respectively. Thus, reaction of a hydrogen-terminated silicon (111) surface with PhHgCCl2Br provides a facile route to multifunctional surfaces possessing both stable silicon-carbon and labile silicon-halogen sites, in a single pot synthesis. The reactive silicon-halogen groups can be utilized for subsequent transformations and, potentially, the construction of more complex organic-silicon hybrid systems.

  13. Predicting internal white oak (Quercus alba) log defect features using surface defect indicator measurements

    Science.gov (United States)

    Ralph E. Thomas

    2012-01-01

    As hardwood trees grow and develop, surface defects such as limb stubs and wounds are overgrown and encapsulated into the tree. Evidence of these defects can remain on the tree's surface for decades and in many instances for the life of the tree. The location and severity of internal defects dictate the quality and value of products that can be obtained from logs...

  14. Effective aerodynamic roughness estimated from airborne laser altimeter measurements of surface features

    NARCIS (Netherlands)

    De Vries, AC; Kustas, WP; Ritchie, JC; Klaassen, W; Menenti, M; Rango, A; Prueger, JH

    2003-01-01

    Aerodynamic roughness length (z(0)) and displacement height (d(0)) are important surface parameters for estimating surface fluxes in numerical models. These parameters are generally determined from wind flow characteristics using logarithmic wind profiles measured at a meteorological tower or by

  15. Effective aerodynamic roughness estimated from airborne laser altimeter measurements of surface features

    NARCIS (Netherlands)

    De Vries, AC; Kustas, WP; Ritchie, JC; Klaassen, W; Menenti, M; Rango, A; Prueger, JH

    2003-01-01

    Aerodynamic roughness length (z(0)) and displacement height (d(0)) are important surface parameters for estimating surface fluxes in numerical models. These parameters are generally determined from wind flow characteristics using logarithmic wind profiles measured at a meteorological tower or by bal

  16. Surface Functionality Features of Porous Silicon Prepared and Treated in Different Conditions

    Directory of Open Access Journals (Sweden)

    Yu. M. Spivak

    2016-01-01

    Full Text Available Hydrophilic layers of porous silicon are prepared by single- or two-step anodization and characterized by evaluating their surface hydrophilicity and contents of functional groups using IR spectroscopy and adsorption of acid-base indicators with different pKa values. The surface functional composition of the synthesized samples is shown to be adjustable depending on the anodization current density. The surface of samples obtained at anodization current density 30 mA/cm2 is predominantly occupied with pKa 2.5 corresponding to ≡Si–OH groups. The increase of current density to 80 mA/cm2 results in the increase of surface functional nonuniformity with the formation of versatile centers, primarily Lewis acidic sites corresponding to Si atoms, as indicated by selective indicator adsorption in agreement with the disappearance of Si–H bonds in IR spectra and overall surface disordering according to SEM and AFM data.

  17. Comparison of Citrus Fruit Surface Defect Classification using Discrete Wavelet Transform, Stationary Wavelet Transform and Wavelet Packet Transform Based Features

    Directory of Open Access Journals (Sweden)

    K. Vijayarekha

    2012-12-01

    Full Text Available The aim of this study is to classify the citrus fruit images based on the external defect using the features extracted in the spectral domain (transform based and to compare the performance of each of the feature set. Automatic classification of agricultural produce by machine vision technology plays a very important role as it improves the quality of grading. Multi resolution analysis using wavelets yields better results for pattern recognition and object classification. This study details about an image processing method applied for classifying three external surface defects of citrus fruit using wavelet transforms based features and an artificial neural network. The Discrete Wavelet Transform (DWT, Stationary Wavelet Transform (SWT and Wavelet Packet Transform (WPT features viz. mean and standard deviation of the details and approximations were extracted from citrus fruit images and used for classifying the defects. The DWT and SWT features were extracted from 40x40 sub-windows of the fruit image. The WPT features were extracted from the full fruit image of size 640x480. The classification results pertaining to the three wavelet transforms are reported and discussed.

  18. Computation of fractal features based on the fractal analysis of surface electromyogram to estimate force of contraction of different muscles.

    Science.gov (United States)

    Poosapadi Arjunan, Sridhar; Kumar, Dinesh Kant

    2014-01-01

    This research study investigates the fractal properties of surface Electromyogram (sEMG) to estimate the force levels of contraction of three muscles with different cross-sectional areas (CSA): m. quadriceps--vastus lateralis, m. biceps brachii, andm. flexor digitorum superficialis. The fractal features were computed based on the fractal analysis of sEMG, signal recorded while performing sustained muscle contraction at different force levels. A comparison was performed between the fractal features and five other features reported in the literature. Linear regression analysis was carried out to determine the relationship between the force of contraction (20-100%) and features of sEMG. The results from the coefficients of regression r² show that the new fractal feature, maximum fractal length of the signal has highest correlation (range 0.88-0.90) when compared with other features which ranges from 0.34 to 0.74 for the three different muscles. This study suggests that the estimation of various levels of sustained contraction of muscles with varied CSA will provide a better insight into the biomechanics model that involves muscle properties and muscle activation.

  19. Morphological features of iPS cells generated from Fabry disease skin fibroblasts using Sendai virus vector (SeVdp).

    Science.gov (United States)

    Kawagoe, Shiho; Higuchi, Takashi; Otaka, Manami; Shimada, Yohta; Kobayashi, Hiroshi; Ida, Hiroyuki; Ohashi, Toya; Okano, Hirotaka J; Nakanishi, Mahito; Eto, Yoshikatsu

    2013-08-01

    We generated iPS cells from human dermal fibroblasts (HDFs) of Fabry disease using a Sendai virus (SeVdp) vector; this method has been established by Nakanishi et al. for pathogenic evaluation. We received SeVdp vector from Nakanishi and loaded it simultaneously with four reprogramming factors (Klf4, Oct4, Sox2, and c-Myc) to HDFs of Fabry disease; subsequently, we observed the presence of human iPS-like cells. The Sendai virus nucleocapsid protein was not detected in the fibroblasts by RT-PCR analysis. Additionally, we confirmed an undifferentiated state, alkaline phosphatase staining, and the presence of SSEA-4, TRA-1-60, and TRA-1-81. Moreover, ultrastructural features of these iPS cells included massive membranous cytoplasmic bodies typical of HDFs of Fabry disease. Thus, we successfully generated human iPS cells from HDFs of Fabry disease that retained the genetic conditions of Fabry disease; also, these abnormal iPS cells could not be easily differentiated into mature cell types such as neuronal cells, cardiomyocytes, etc. because of a massive accumulation of membranous cytoplasmic bodies in lysosomes, possibly the persistent damages of intracellular architecture.

  20. The 2D surfaces that generate Newtonian and general relativistic orbits with small eccentricities

    CERN Document Server

    Middleton, Chad A

    2015-01-01

    Embedding diagrams prove to be quite useful when learning general relativity as they offer a way of visualizing spacetime curvature through warped two dimensional (2D) surfaces. In this manuscript we present a different 2D construct that also serves as a useful conceptual tool for gaining insight into gravitation, in particular, orbital dynamics - namely the cylindrically symmetric surfaces that generate Newtonian and general relativistic orbits with small eccentricities. Although we first show that no such surface exists that can exactly reproduce the arbitrary bound orbits of Newtonian gravitation or of general relativity (or, more generally, of any spherically symmetric potential), surfaces do exist that closely approximate the resulting orbital motion for small eccentricities; exactly the regime that describes the motion of the solar system planets. These surfaces help to illustrate the similarities, as well as the differences, between the two theories of gravitation (i.e. stationary elliptical orbits in ...

  1. Restoration of defects generated on the DAST crystal surface by scanning with AFM cantilever tip

    Energy Technology Data Exchange (ETDEWEB)

    Nanjo, Hiroshi; Komatsu, Kyoji; Suzuki, Toshishige M

    2004-10-01

    We have developed a simple method to restore the defects and holes generated on the (001) surface of 4-(4-Dimethylaminostyryl)-1-methylpyridinium tosylate (DAST) crystal by scanning the crystal with a cantilever tip of an atomic force microscope (AFM). The change in the surface morphology upon repeated scan process was followed by AFM observation at appropriate intervals. By adjustment of applied force on the cantilever, molecular-scale flatness on the crystal surface was restored. We proposed the following mechanism for the restoration: AFM tip carries the small fragment of DAST near step-edge and fills the holes or defects on the surface. After several times scanning of the AFM tip with the fragment, the defect-free surface was restored on the DAST crystal by filling the fragment in satisfying the ionic interaction around the holes.

  2. Surface Integral Method for the Second Harmonic Generation in Metal Nanoparticles

    CERN Document Server

    Forestiere, Carlo; Miano, Giovanni

    2013-01-01

    Second harmonic (SH) radiation in metal nanoparticles is generated by both nonlocal-bulk and local-surface SH sources, induced by the electromagnetic field at the fundamental frequency. We propose a surface integral equation (SIE) method for evaluating the SH radiation generated by metal nanoparticles with arbitrary shapes, considering both the local-surface and nonlocal-bulk SH sources. We demonstrate that the contribution of the nonlocal-bulk SH source to the SH electromagnetic field can be rigorously taken into account through an equivalent surface magnetic current. We numerically solve the SIE problem by using the Galerkin method and the Rao-Wilton-Glisson basis functions in the framework of the distribution theory. The accuracy of the proposed method is verified by comparison with the SH-Mie formulation in the case of SH generation from a spherical nanoparticle. As an example of a complex-shaped particle, we investigate the SH radiation generated from a triangular nano-prism. The method paves the way for...

  3. Biomimetic walking trajectory generation of humanoid robot on an inclined surface using Fourier series.

    Science.gov (United States)

    Park, Ill-Woo; Kim, Jung-Yup

    2014-10-01

    This article describes a novel method to generate a biomimetic walking trajectory for a biped humanoid robot on an inclined surface. We assume that the configuration of the inclined surface is known, and we solve the human-like walking trajectory generation problem by obtaining the solution from the desired zero moment point (ZMP) trajectory to the center of gravity (CoG) trajectory. We present an analytic solution for the walking trajectory generation by using Fourier series. From the given ZMP trajectory biomimetically represented by the Fourier series, we focus on how to find the CoG trajectory in an analytical way. A time-segmentation based approach is adopted for generating the trajectories. The trajectory functions need to be continuous between the segments; thus, the solution is found by calculating the coefficients under these connectivity conditions. We derive a general form of the ZMP equation using a simple inverted pendulum model (SIPM), which includes the ZMP and the CoG trajectories in the horizontal and vertical directions to quantify the walking parameters on the inclined surface. The performance of the proposed approach is verified by conducting walking simulations using a full-body dynamic simulator on three different inclined surfaces and comparing them to the authors' previous approach.

  4. Second-Harmonic Generation Scanning Microscopy on Domains in Al Surfaces

    DEFF Research Database (Denmark)

    Pedersen, Kjeld; Bozhevolnyi, Sergey I.

    1999-01-01

    Scanning optical second-harmonic generation microscopy has been used to investigate domains in the surface of polycrystaline Al. Strong contrast among the crystalline grains is obtained due to variations in their crystallographic orientations and thus also nonlinear response. The origin of the co...

  5. Simulation of an Underwater Acoustic Communication Channel Characterized by Wind-Generated Surface Waves and Bubbles

    NARCIS (Netherlands)

    Dol, H.S.; Ainslie, M.A.; Colin, M.E.G.D.; Janmaat, J.

    2012-01-01

    Sea surface scattering by wind-generated waves and bubbles is regarded to be the main nonplatform-related cause of the time variability of shallow acoustic communication channels. Simulations for predicting the quality of acoustic communication links in such channels thus require adequate modelling

  6. Simulation of an Underwater Acoustic Communication Channel Characterized by Wind-Generated Surface Waves and Bubbles

    NARCIS (Netherlands)

    Dol, H.S.; Colin, M.E.G.D.; Ainslie, M.A.; Walree, P.A. van; Janmaat, J.

    2013-01-01

    Abstract—Sea-surface scattering by wind-generated waves and bubbles is regarded to be the main nonplatform related cause of the time variability of shallow acoustic communication channels. Simulations for predicting the quality of acoustic communication links in such channels thus require adequate m

  7. Simulation of an Underwater Acoustic Communication Channel Characterized by Wind-Generated Surface Waves and Bubbles

    NARCIS (Netherlands)

    Dol, H.S.; Colin, M.E.G.D.; Ainslie, M.A.; Walree, P.A. van; Janmaat, J.

    2012-01-01

    Sea surface scattering by wind-generated waves and bubbles is regarded to be the main non-platform related cause of the time variability of shallow acoustic communication channels. Simulations for predicting the quality of acoustic communication links in such channels thus require adequate modeling

  8. Ultrahigh-frequency surface acoustic wave generation for acoustic charge transport in silicon

    NARCIS (Netherlands)

    Büyükköse, S.; Vratzov, B.; van der Veen, Johan (CTIT); Santos, P.V.; van der Wiel, Wilfred Gerard

    2013-01-01

    We demonstrate piezo-electrical generation of ultrahigh-frequency surface acoustic waves on silicon substrates, using high-resolution UV-based nanoimprint lithography, hydrogen silsequioxane planarization, and metal lift-off. Interdigital transducers were fabricated on a ZnO layer sandwiched between

  9. The turn angle gauge of generating type with an element on surface acoustic waves

    Directory of Open Access Journals (Sweden)

    Lepikh Ya. I.

    2009-06-01

    Full Text Available The results of intellectualized angle of rotation sensor with an element on the surface acoustic waves (SAW development are presented. The generating type sensor block diagram, in which the element on SAW plays a role of the appropriate line of a delay is described. The sensor basic characteristics are given and the area of its application are shown.

  10. Local excitation of surface plasmon polaritons by second-harmonic generation in crystalline organic nanofibers

    DEFF Research Database (Denmark)

    Skovsen, Esben; Søndergaard, Thomas; Fiutowski, Jacek

    2012-01-01

    Coherent local excitation of surface plasmon polaritons (SPPs) by second-harmonic generation (SHG) in aligned crystalline organic functionalized para-phenylene nanofibers deposited on a thin silver film is demonstrated. The excited SPPs are characterized using angle-resolved leakage radiation...

  11. Literature Survey Concerning State of the Art and Surface Generation in High Speed Milling

    DEFF Research Database (Denmark)

    Bissacco, Giuliano

    This report constitutes a short description of a literature survey concerning the state of the art and latest achievements on the rather new and powerful technology of high speed milling and its modelling, particularly looking at modelling of the generated surfaces. This task has been conducted i...

  12. Second-Harmonic Generation Scanning Microscopy on Domains in Al Surfaces

    DEFF Research Database (Denmark)

    Pedersen, Kjeld; Bozhevolnyi, Sergey I.

    1999-01-01

    Scanning optical second-harmonic generation microscopy has been used to investigate domains in the surface of polycrystaline Al. Strong contrast among the crystalline grains is obtained due to variations in their crystallographic orientations and thus also nonlinear response. The origin of the co...

  13. Simulation of an Underwater Acoustic Communication Channel Characterized by Wind-Generated Surface Waves and Bubbles

    NARCIS (Netherlands)

    Dol, H.S.; Ainslie, M.A.; Colin, M.E.G.D.; Janmaat, J.

    2012-01-01

    Sea surface scattering by wind-generated waves and bubbles is regarded to be the main nonplatform-related cause of the time variability of shallow acoustic communication channels. Simulations for predicting the quality of acoustic communication links in such channels thus require adequate modelling

  14. Simulation of an Underwater Acoustic Communication Channel Characterized by Wind-Generated Surface Waves and Bubbles

    NARCIS (Netherlands)

    Dol, H.S.; Colin, M.E.G.D.; Ainslie, M.A.; Walree, P.A. van; Janmaat, J.

    2013-01-01

    Abstract—Sea-surface scattering by wind-generated waves and bubbles is regarded to be the main nonplatform related cause of the time variability of shallow acoustic communication channels. Simulations for predicting the quality of acoustic communication links in such channels thus require adequate m

  15. Simulation of an Underwater Acoustic Communication Channel Characterized by Wind-Generated Surface Waves and Bubbles

    NARCIS (Netherlands)

    Dol, H.S.; Colin, M.E.G.D.; Ainslie, M.A.; Walree, P.A. van; Janmaat, J.

    2012-01-01

    Sea surface scattering by wind-generated waves and bubbles is regarded to be the main non-platform related cause of the time variability of shallow acoustic communication channels. Simulations for predicting the quality of acoustic communication links in such channels thus require adequate modeling

  16. Real time non-rigid surface detection based on binary robust independent elementary features

    Directory of Open Access Journals (Sweden)

    Chuin-Mu Wang

    2015-04-01

    Full Text Available The surface deformation detection of an object has been a very popular research project in recent years; in human vision, we can easily detect the location of the target and that scale of the surface rotation, and change of the viewpoint makes the surface deformation, but in a vision of the computer is a challenge. In those backgrounds of questions, we can propose a framework that is the surface deformation, which is based on the detection method of BRIEF to calculate object surface deformation. But BRIEF calculation has some problem that can’t rotate and change character; we also propose a useful calculation method to solve the problem, and the method proved by experiment can overcome the problem, by the way, it's very useful. The average operation time every picture in continuous image is 50∼80 ms in 2.5 GHz computer, let us look back for some related estimation technology of surface deformation, and there are still a few successful project that is surface deformation detection in the document.

  17. The effect of plutonium dioxide water surface coverage on the generation of hydrogen and oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Veirs, Douglas K. [Los Alamos National Laboratory; Berg, John M. [Los Alamos National Laboratory; Crowder, Mark L. [Savannah River National Laboratory

    2012-06-20

    The conditions for the production of oxygen during radiolysis of water adsorbed onto plutonium dioxide powder are discussed. Studies in the literature investigating the radiolysis of water show that both oxygen and hydrogen can be generated from water adsorbed on high-purity plutonium dioxide powder. These studies indicate that there is a threshold in the amount of water below which oxygen is not generated. The threshold is associated with the number of monolayers of adsorbed water and is shown to occur at approximately two monolayers of molecularly adsorbed water. Material in equilibrium with 50% relative humidity (RH) will be at the threshold for oxygen generation. Using two monolayers of molecularly adsorbed water as the threshold for oxygen production, the total pressure under various conditions is calculated assuming stoichiometric production of hydrogen and oxygen. The specific surface area of the oxide has a strong effect on the final partial pressure. The specific surface areas resulting in the highest pressures within a 3013 container are evaluated. The potential for oxygen generation is mitigated by reduced relative humidity, and hence moisture adsorption, at the oxide surface which occurs if the oxide is warmer than the ambient air. The potential for oxygen generation approaches zero as the temperature difference between the ambient air and the material approaches 6 C.

  18. Characteristics, seasonal distribution and surface degradation features of microplastic pellets along the Goa coast, India

    Digital Repository Service at National Institute of Oceanography (India)

    Veerasingam, S.; Saha, M.; Suneel, V.; Vethamony, P.; Rodrigues, A.C.; Bhattacharyya, S.; Naik, B.G.

    are generated when macro-sized plastics in the marine environment are physically (wind, wave and current), chemically (UV radiation) and biologically (microbial activity) degraded and fragmented into micro-sized (<5 mm) particles (Cole et al., 2011; GESAMP...-oxidation (Endo et al., 2005). Photo-oxidation increases the rate of chemical reaction and generates greater degradation. This degradation continues until MPPs become nano-plastics (Acosta-Coley and Olivero-Verbel, 2015). The relative abundance of carbonyl...

  19. Dispersion analysis of passive surface-wave noise generated during hydraulic-fracturing operations

    Science.gov (United States)

    Forghani-Arani, Farnoush; Willis, Mark; Snieder, Roel; Haines, Seth S.; Behura, Jyoti; Batzle, Mike; Davidson, Michael

    2014-01-01

    Surface-wave dispersion analysis is useful for estimating near-surface shear-wave velocity models, designing receiver arrays, and suppressing surface waves. Here, we analyze whether passive seismic noise generated during hydraulic-fracturing operations can be used to extract surface-wave dispersion characteristics. Applying seismic interferometry to noise measurements, we extract surface waves by cross-correlating several minutes of passive records; this approach is distinct from previous studies that used hours or days of passive records for cross-correlation. For comparison, we also perform dispersion analysis for an active-source array that has some receivers in common with the passive array. The active and passive data show good agreement in the dispersive character of the fundamental-mode surface-waves. For the higher mode surface waves, however, active and passive data resolve the dispersive properties at different frequency ranges. To demonstrate an application of dispersion analysis, we invert the observed surface-wave dispersion characteristics to determine the near-surface, one-dimensional shear-wave velocity.

  20. Surface electromyogram analysis of the direction of isometric torque generation by the first dorsal interosseous muscle

    Science.gov (United States)

    Zhou, Ping; Suresh, Nina L.; Zev Rymer, William

    2011-06-01

    The objective of this study was to determine whether a novel technique using high density surface electromyogram (EMG) recordings can be used to detect the directional dependence of muscle activity in a multifunctional muscle, the first dorsal interosseous (FDI). We used surface EMG recordings with a two-dimensional electrode array to search for inhomogeneous FDI activation patterns with changing torque direction at the metacarpophalangeal joint, the locus of action of the FDI muscle. The interference EMG distribution across the whole FDI muscle was recorded during isometric contraction at the same force magnitude in five different directions in the index finger abduction-flexion plane. The electrode array EMG activity was characterized by contour plots, interpolating the EMG amplitude between electrode sites. Across all subjects the amplitude of the flexion EMG was consistently lower than that of the abduction EMG at the given force. Pattern recognition methods were used to discriminate the isometric muscle contraction tasks with a linear discriminant analysis classifier, based on the extraction of two different feature sets of the surface EMG signal: the time domain (TD) feature set and a combination of autoregressive coefficients and the root mean square amplitude (AR+RMS) as a feature set. We found that high accuracies were obtained in the classification of different directions of the FDI muscle isometric contraction. With a monopolar electrode configuration, the average overall classification accuracy from nine subjects was 94.1 ± 2.3% for the TD feature set and 95.8 ± 1.5% for the AR+RMS feature set. Spatial filtering of the signal with bipolar electrode configuration improved the average overall classification accuracy to 96.7 ± 2.7% for the TD feature set and 98.1 ± 1.6% for the AR+RMS feature set. The distinct EMG contour plots and the high classification accuracies obtained from this study confirm distinct interference EMG pattern distributions as a

  1. Computation and Evaluation of Features of Surface Electromyogram to Identify the Force of Muscle Contraction and Muscle Fatigue

    Directory of Open Access Journals (Sweden)

    Sridhar P. Arjunan

    2014-01-01

    Full Text Available The relationship between force of muscle contraction and muscle fatigue with six different features of surface electromyogram (sEMG was determined by conducting experiments on thirty-five volunteers. The participants performed isometric contractions at 50%, 75%, and 100% of their maximum voluntary contraction (MVC. Six features were considered in this study: normalised spectral index (NSM5, median frequency, root mean square, waveform length, normalised root mean square (NRMS, and increase in synchronization (IIS index. Analysis of variance (ANOVA and linear regression analysis were performed to determine the significance of the feature with respect to the three factors: muscle force, muscle fatigue, and subject. The results show that IIS index of sEMG had the highest correlation with muscle fatigue and the relationship was statistically significant (P0.05.

  2. Detecting Translation Errors in CAD Surfaces and Preparing Geometries for Mesh Generation

    Energy Technology Data Exchange (ETDEWEB)

    Petersson, N Anders; Chand, K K

    2001-08-27

    The authors have developed tools for the efficient preparation of CAD geometries for mesh generation. Geometries are read from IGES files and then maintained in a boundary-representation consisting of a patchwork of trimmed and untrimmed surfaces. Gross errors in the geometry can be identified and removed automatically while a user interface is provided for manipulating the geometry (such as correcting invalid trimming curves or removing unwanted details). Modifying the geometry by adding or deleting surfaces and/or sectioning it by arbitrary planes (e.g. symmetry planes) is also supported. These tools are used for robust and accurate geometry models for initial mesh generation and will be applied to in situ mesh generation requirements of moving and adaptive grid simulations.

  3. Generation of surface waves by an underwater moving bottom: Experiments and application to tsunami modelling

    CERN Document Server

    Jamin, Timothée; Ruiz-Chavarría, Gerardo; Berhanu, Michael; Falcon, Eric

    2014-01-01

    We report laboratory experiments on surface waves generated in a uniform fluid layer whose bottom undergoes a sudden upward motion. Simultaneous measurements of the free-surface deformation and the fluid velocity field are focused on the role of the bottom kinematics in wave generation. We observe that the fluid layer transfers bottom motion to the free surface as a temporal high-pass filter coupled with a spatial low-pass filter. Both filter effects are usually neglected in tsunami warning systems. Our results display good agreement with a prevailing linear theory without fitting parameter. Based on our experimental data, we provide a new theoretical approach for the rapid kinematics limit that is applicable even for non-flat bottoms: a key step since most approaches assume a uniform depth. This approach can be easily appended to tsunami simulations under arbitrary topography.

  4. Modeling the spectrum of infrasonic hydroacoustic radiation generated by the sea surface under storm conditions

    Science.gov (United States)

    Zapevalov, A. S.; Pokazeev, K. V.

    2016-09-01

    Generation of infrasonic radiation into a water medium by sea surface waves is analyzed. The analysis is carried out for the situation in which the infrasound is generated by surface waves with frequencies close to those of dominant waves. The presence of two wave systems on the sea surface is assumed: swell and wind waves. It is shown that if the frequencies of spectral peaks of wind waves and swell diverge by 20%, the maximum value of the radiation spectrum decreases by approximately 40% (if the general directions of the two wave systems are oriented strictly towards each other). A deviation of the general directions of the two wave systems from the opposite direction by 45° leads to a decrease in the maximum value of the radiation spectrum by more than two times.

  5. Polarization dependent formation of femtosecond laser-induced periodic surface structures near stepped features

    Science.gov (United States)

    Murphy, Ryan D.; Torralva, Ben; Adams, David P.; Yalisove, Steven M.

    2014-06-01

    Laser-induced periodic surface structures (LIPSS) are formed near 110 nm-tall Au microstructured edges on Si substrates after single-pulse femtosecond irradiation with a 150 fs pulse centered near a 780 nm wavelength. We investigate the contributions of Fresnel diffraction from step-edges and surface plasmon polariton (SPP) excitation to LIPSS formation on Au and Si surfaces. For certain laser polarization vector orientations, LIPSS formation is dominated by SPP excitation; however, when SPP excitation is minimized, Fresnel diffraction dominates. The LIPSS orientation and period distributions are shown to depend on which mechanism is activated. These results support previous observations of the laser polarization vector influencing LIPSS formation on bulk surfaces.

  6. Polarization dependent formation of femtosecond laser-induced periodic surface structures near stepped features

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, Ryan D. [Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48109 (United States); Torralva, Ben [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States); Adams, David P. [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States); Yalisove, Steven M. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2014-06-09

    Laser-induced periodic surface structures (LIPSS) are formed near 110 nm-tall Au microstructured edges on Si substrates after single-pulse femtosecond irradiation with a 150 fs pulse centered near a 780 nm wavelength. We investigate the contributions of Fresnel diffraction from step-edges and surface plasmon polariton (SPP) excitation to LIPSS formation on Au and Si surfaces. For certain laser polarization vector orientations, LIPSS formation is dominated by SPP excitation; however, when SPP excitation is minimized, Fresnel diffraction dominates. The LIPSS orientation and period distributions are shown to depend on which mechanism is activated. These results support previous observations of the laser polarization vector influencing LIPSS formation on bulk surfaces.

  7. Gridded Surface Subsurface Hydrologic Analysis Modeling for Analysis of Flood Design Features at the Picayune Strand Restoration Project

    Science.gov (United States)

    2016-08-01

    ER D C/ CH L TR -1 6 -1 4 Gridded Surface Subsurface Hydrologic Analysis Modeling for Analysis of Flood Design Features at the Picayune...impacting the level of flood protection of adjacent landowners. To ensure the current level of flood protection is maintained, a hydrologic model was...Subsurface Hydrologic Analysis (GSSHA) model was selected for this effort. The GSSHA model simulates fully coupled rainfall distribution, extraction

  8. SAR Analysis of the ocean surface : aplication to the NW mediterranean marine pollution and dynamic features

    OpenAIRE

    Redondo Apraiz, José Manuel; Platonov, A.; Grau Barceló, Joan

    2009-01-01

    The interaction between multiple scales in nature and mainly in turbulent flows produces fractals or multifractal structures. We use multi-fractal analysis to investigate the scales and influence of stratification in different types of surface eddies in the ocean, and specially, near the coastline. We will also show and discuss the structure and residence time in oil spills and slicks in the ocean surface. This method, of multifractal analysis on the intensity SAR signals, as an example will ...

  9. Friction Reduction of Chrome-Coated Surface with Micro-Dimple Arrays Generated by Electrochemical Micromachining

    Science.gov (United States)

    Chen, Xiaolei; Qu, Ningsong; Hou, Zhibao; Wang, Xiaolei; Zhu, Di

    2017-02-01

    Surface coating and surface texture play a significant role in enhancing the tribological properties of mechanical components. In this study, to further improve the tribological properties of a chrome-coated surface, arrays of circular- and square-shaped micro-dimples were generated on chrome-coated surfaces via electrochemical machining. Through-mask electrochemical micromachining (TMEMM) is a popular electrochemical micromachining method for generating micro-dimple arrays. However, photolithography is a necessary process in conventional TMEMM before electrochemical micromachining, which is time-consuming and expensive when used in mass production. A reusable polydimethylsiloxane mask was introduced to prepare the micro-dimples. Circular micro-dimples of 120 μm diameter and square micro-dimples of 106 μm side length were fabricated on a chrome-coated surface. The results of friction tests indicated that at a load of 220 N, 10 μm deep micro-dimples reduced the coefficient of friction (CoF) significantly compared to an untextured surface. At a load of 320 and 420 N, the CoF continually decreased when the depth of the micro-dimples was increased from 0 to 20 μm. In addition, the results showed that, compared to circular micro-dimples, square micro-dimples contributed to a higher friction reduction ratio under the same conditions. The best friction reduction ratio was found for square dimples with a depth of 20 μm.

  10. Developments in convective heat transfer models featuring seamless and selected detail surfaces, employing electroless plating

    Science.gov (United States)

    Stalmach, C. J., Jr.

    1975-01-01

    Several model/instrument concepts employing electroless metallic skin were considered for improvement of surface condition, accuracy, and cost of contoured-geometry convective heat transfer models. A plated semi-infinite slab approach was chosen for development and evaluation in a hypersonic wind tunnel. The plated slab model consists of an epoxy casting containing fine constantan wires accurately placed at specified surface locations. An electroless alloy was deposited on the plastic surface that provides a hard, uniformly thick, seamless skin. The chosen alloy forms a high-output thermocouple junction with each exposed constantan wire, providing means of determining heat transfer during tunnel testing of the model. A selective electroless plating procedure was used to deposit scaled heatshield tiles on the lower surface of a 0.0175-scale shuttle orbiter model. Twenty-five percent of the tiles were randomly selected and plated to a height of 0.001-inch. The purpose was to assess the heating effects of surface roughness simulating misalignment of tiles that may occur during manufacture of the spacecraft.

  11. Age-related leaf characteristics of surface features and ultrastructure of Dendropanax morbifera.

    Science.gov (United States)

    Kim, Ki Woo; Koo, Young Kuk; Yoon, Chul Jong

    2012-02-01

    Age-related morphological and anatomical changes were investigated by light and electron microscopy with juvenile and adult leaves of Dendropanax morbifera. Most juvenile leaves were glossy and palmate with five deep and narrow lobes divided nearly to two-thirds of the leaf base. Adult leaves were thick and possessed three lobes divided nearly to half of the leaf base. Stomata were ovoid and found on the abaxial surface. The epicuticular waxes of the plant included platelets, angular rodlets and threads. Platelets were attached to the surface at various angles. Distinct angular rodlets could be found on either the adaxial or the abaxial surface. Platelets on surface undulations occurred exclusively on the abaxial surface of adult leaves. Juvenile leaves were ca. 150 μm thick and had few intercellular spaces. Adult leaves were nearly two times thicker than juvenile leaves, and showed highly vacuolated cells and large intercellular spaces. The cuticle proper was apparent on the epidermis and showed distinctly alternating lamellate structures in juvenile leaves. The epidermal cell wall of adult leaves was covered with a cuticle layer for which a lamellate structure was not found. These results suggest that the species is heteroblastic in leaf characteristics with increasing leaf age.

  12. Mixed-Mode Fracture Behavior and Related Surface Topography Feature of a Typical Sandstone

    Science.gov (United States)

    Ren, L.; Xie, L. Z.; Xie, H. P.; Ai, T.; He, B.

    2016-08-01

    The geo-mechanical properties of reservoirs, especially the morphology of the rock surface and the fracture properties of rocks, are of great importance in the modeling and simulation of hydraulic processes. To better understand these fundamental issues, five groups of mixed-mode fracture tests were conducted on sandstone using edge-cracked semi-circular bend specimens. Accordingly, the fracture loads, growth paths and fracture surfaces for different initial mixities of the mixed-mode loadings from pure mode I to pure mode II were then determined. A surface topography measurement for each rough fracture surface was conducted using a laser profilometer, and the fractal properties of these surfaces were then investigated. The fracture path evolution mechanism was also investigated via optical microscopy. Moreover, the mixed-mode fracture strength envelope and the crack propagation trajectories of sandstone were theoretically modeled using three widely accepted fracture criteria (i.e., the MTS, MSED and MERR criterions). The published test results in Hasanpour and Choupani (World Acad Sci Eng Tech 41:764-769, 2008) for limestone were also theoretically investigated to further examine the effectiveness of the above fracture criteria. However, none of these criteria could accurately predict the fracture envelopes of both sandstone and limestone. To better estimate the fracture strength of mixed-mode fractures, an empirical maximum tensile stress (EMTS) criterion was proposed and found to achieve good agreement with the test results. Finally, a uniformly pressurized fracture model was simulated for low pressurization rates using this criterion.

  13. Variable aberration generator using a high-order even aspheric singlet for testing optical surfaces

    Science.gov (United States)

    Lu, Jinfeng; Chen, Shanyong; Xue, Shuai

    2016-10-01

    Traditional null optics is generally designed for a particular optical surface. It must be redesigned when the test surface is changed no matter the null optic is reflective, transmitted or a CGH. Development of advanced optical machining and testing based on deterministic figuring and null test makes it possible to apply high-order aspheres. This paper presents a plano-concave singlet to realize variable aberration correction for testing different surfaces. The concave surface is an even asphere with high-order terms. By changing the axial distances among the transmission sphere, the null singlet and the test surface, variable aberrations are generated to meet the aberration balance requirement for various surfaces. The residual aberrations are confirmed within the vertical dynamic range of measurement of the interferometer. It enables flexible testing of optical surfaces without dedicated null optics. The optical design verifies that the aspheric singlet can be used to test conic surfaces with different conic constant and radius of curvature ranging from ellipsoid, paraboloid to hyperboloid and an even asphere.

  14. A Survey of Surface Modification Techniques for Next-Generation Shape Memory Polymer Stent Devices

    Directory of Open Access Journals (Sweden)

    Tina Govindarajan

    2014-08-01

    Full Text Available The search for a single material with ideal surface properties and necessary mechanical properties is on-going, especially with regard to cardiovascular stent materials. Since the majority of stent problems arise from surface issues rather than bulk material deficiencies, surface optimization of a material that already contains the necessary bulk properties is an active area of research. Polymers can be surface-modified using a variety of methods to increase hemocompatibilty by reducing either late-stage restenosis or acute thrombogenicity, or both. These modification methods can be extended to shape memory polymers (SMPs, in an effort to make these materials more surface compatible, based on the application. This review focuses on the role of surface modification of materials, mainly polymers, to improve the hemocompatibility of stent materials; additional discussion of other materials commonly used in stents is also provided. Although shape memory polymers are not yet extensively used for stents, they offer numerous benefits that may make them good candidates for next-generation stents. Surface modification techniques discussed here include roughening, patterning, chemical modification, and surface modification for biomolecule and drug delivery.

  15. Generation of laser-induced periodic surface structures on transparent material-fused silica

    Science.gov (United States)

    Schwarz, Simon; Rung, Stefan; Hellmann, Ralf

    2016-05-01

    We report on a comparison between simulated and experimental results for the generation of laser-induced periodic surface structures with low spatial frequency on dielectrics. Using the established efficacy factor theory extended by a Drude model, we determine the required carrier density for the generation of low spatial frequency LIPSS (LSFL) and forecast their periodicity and orientation. In a subsequent calculative step, we determine the fluence of ultrashort laser pulses necessary to excite this required carrier density in due consideration of the pulse number dependent ablation threshold. The later calculation is based on a rate equation including photo- and avalanche ionization and derives appropriate process parameters for a selective generation of LSFL. Exemplarily, we apply this approach to the generation of LSFL on fused silica using a 1030 nm femtosecond laser. The experimental results for the orientation and spatial periodicity of LSFL reveal excellent agreement with the simulation.

  16. Invariant Surface EMG Feature Against Varying Contraction Level for Myoelectric Control Based on Muscle Coordination.

    Science.gov (United States)

    He, Jiayuan; Zhang, Dingguo; Sheng, Xinjun; Li, Shunchong; Zhu, Xiangyang

    2015-05-01

    Variations in muscle contraction effort have a substantial impact on performance of pattern recognition based myoelectric control. Though incorporating changes into training phase could decrease the effect, the training time would be increased and the clinical viability would be limited. The modulation of force relies on the coordination of multiple muscles, which provides a possibility to classify motions with different forces without adding extra training samples. This study explores the property of muscle coordination in the frequency domain and found that the orientation of muscle activation pattern vector of the frequency band is similar for the same motion with different force levels. Two novel features based on discrete Fourier transform and muscle coordination were proposed subsequently, and the classification accuracy was increased by around 11% compared to the traditional time domain feature sets when classifying nine classes of motions with three different force levels. Further analysis found that both features decreased the difference among different forces of the same motion ) and maintained the distance among different motions p > 0.1). This study also provided a potential way for simultaneous classification of hand motions and forces without training at all force levels.

  17. Microstructural features of water fern Salvinia natans (L. All. organ surfaces

    Directory of Open Access Journals (Sweden)

    M.M. Shcherbatiuk

    2015-05-01

    Full Text Available The microstructure of the organs surface of the water fern Salvinia natans (L. All. has been studied under scanning electron microscope. It was established that the existence on the border between air and water environments is suported by specific microstructure of floating leaves. The adaxial side of floating leaves has well-developed cuticle and stomata placed below the level of epidermis, while abaxial surface of such leaves and submerged modified leaves are characterized by ultra-thin cell walls of the epidermis and numerous filamentous trichomes. We calculated number of stomata per unit area of leaves and the average diameter of stomata. It is claimed that the structure of wall of the sporocarp promotes the passage of the annual summer-green rhythm. Sporocarp provides diving of mega- and microsporangia to the bottom of the water reservoir in autumn and their raising on the water surface in the spring after destruction of its walls.

  18. Symmetry plays a key role in the erasing of patterned surface features

    Energy Technology Data Exchange (ETDEWEB)

    Benzaquen, Michael; Salez, Thomas; Raphaël, Elie [Laboratoire de Physico-Chimie Théorique, UMR CNRS Gulliver 7083, ESPCI ParisTech, PSL Research University, 75005 Paris (France); Ilton, Mark; Massa, Michael V.; Fowler, Paul [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Dalnoki-Veress, Kari, E-mail: dalnoki@mcmaster.ca [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Laboratoire de Physico-Chimie Théorique, UMR CNRS Gulliver 7083, ESPCI ParisTech, PSL Research University, 75005 Paris (France)

    2015-08-03

    We report on how the relaxation of patterns prepared on a thin film can be controlled by manipulating the symmetry of the initial shape. The validity of a lubrication theory for the capillary-driven relaxation of surface profiles is verified by atomic force microscopy measurements, performed on films that were patterned using focused laser spike annealing. In particular, we observe that the shape of the surface profile at late times is entirely determined by the initial symmetry of the perturbation, in agreement with the theory. The results have relevance in the dynamical control of topographic perturbations for nanolithography and high density memory storage.

  19. Specific features of heat transfer on the external surface of smoke stacks blown by wind

    Science.gov (United States)

    Maneev, A. P.; Terekhov, V. I.

    2015-03-01

    Results of a full-scale experiment on studying heat transfer on the surface of a reinforced-concrete smoke stack blown by wind at the value of Reynolds number Re = 1.05 × 107 are presented. Comparison of the experimental results with the experimental data obtained previously by other researchers under laboratory conditions at Re cylinder in a transcritical streamlining mode. The data obtained in the present study open the possibility to estimate the average values of heat transfer coefficient on the surface of smoke stacks in a flow of atmospheric air at 4 × 106 < Re < 107.

  20. Travel-time correction surface generation for the DOE Knowledge Base

    Energy Technology Data Exchange (ETDEWEB)

    Hipp, J.; Young, C.; Keyser, R.

    1997-08-01

    The DOE Knowledge Base data storage and access model consists of three parts: raw data processing, intermediate surface generation, and final output surface interpolation. The paper concentrates on the second step, surface generation, specifically applied to travel-time correction data. The surface generation for the intermediate step is accomplished using a modified kriging solution that provides robust error estimates for each for each interpolated point and satisfies many important physical requirements including differing quality data points, user-definable range of influence for each point, blend to background values for both interpolated values and error estimates beyond the ranges, and the ability to account for the effects of geologic region boundaries. These requirements are outlined and discussed and are linked to requirements specified for the final output model in the DOE Knowledge Base. Future work will focus on testing the entire Knowledge Base model using the regional calibration data sets which are being gathered by researchers at Los Alamos and Lawrence Livermore National Laboratories.

  1. THE HYPERBOLOID OF REVOLUTION OF ONE NAPPE – A RULED SURFACE GENERATING CONICS

    Directory of Open Access Journals (Sweden)

    OPREA Gabriel

    2013-11-01

    Full Text Available The paper intends to underline the property of the hyperboloid of revolution of one nappe to generate on its surface, when it is cut by a plane, the three known conics (ellipse, hyperbola and parabola.Cutting this surface by a plane, we find the equation of the section to be the general equation of a conic. Depending on the parameters of this equation, we can establish the nature of the conic. The paper intends to emphasize the property of similarity between the ruled hyperboloidal surfaces of revolution and the conic ones, regarding their capacity to “house” conics on their surfaces; it also points out the existence of an alternative for the Dandelin′s theorem in the case of the hyperboloid.

  2. Symmetry Analysis of ZnSe(100) Surface in Air By Second Harmonic Generation

    CERN Document Server

    Song, X; Maripuu, R; Siegbahn, Kai; Song, Xiangyang; Neumann, Arnold; Maripuu, Rein; Siegbahn, Kai

    2002-01-01

    Polarized and azimuthal dependencies of optical second harmonics generation (SHG) at the surface of noncentrosymmetric semiconductor crystals have been measured on polished surfaces of ZnSe(100), using a fundamental wavelength of 1.06$\\mu m$. The SHG intensity patterns were analyzed for all four combination of p- and s-polarized incidence and output, considering both the bulk and surface optical nonlinearities in the electric dipole approximation. We found that the measurement using $S_{in}-S_{out}$ is particularly useful in determining the symmetry of the oxdized layer interface, which would lower the effective symmetry of the surface from $C_{4v}$ to $C_{2v}.$ We also have shown that the [011] and [0$\\bar{1}$1] directions can be distinguished through the analysis of p-incident and p-output confugration.

  3. Acoustical breakdown of materials by focusing of laser-generated Rayleigh surface waves

    Science.gov (United States)

    Veysset, David; Maznev, A. A.; Veres, István A.; Pezeril, Thomas; Kooi, Steven E.; Lomonosov, Alexey M.; Nelson, Keith A.

    2017-07-01

    Focusing of high-amplitude surface acoustic waves leading to material damage is visualized in an all-optical experiment. The optical setup includes a lens and an axicon that focuses an intense picosecond excitation pulse into a ring-shaped pattern at the surface of a gold-coated glass substrate. Optical excitation induces a surface acoustic wave (SAW) that propagates in the plane of the sample and converges toward the center. The evolution of the SAW profile is monitored using interferometry with a femtosecond probe pulse at variable time delays. The quantitative analysis of the full-field images provides direct information about the surface displacement profiles, which are compared to calculations. The high stress at the focal point leads to the removal of the gold coating and, at higher excitation energies, to damage of the glass substrate. The results open the prospect for testing material strength on the microscale using laser-generated SAWs.

  4. Generation of Bessel Surface Plasmon Polaritons in a Finite-Thickness Metal Film

    Directory of Open Access Journals (Sweden)

    S. N. Kurilkina

    2013-01-01

    Full Text Available A theory of generation of low- and high-index Bessel surface plasmon polaritons and their superposition in a metal film of a finite thickness is developed. Correct analytical expressions are obtained for the field of two families of Bessel surface plasmon polariton modes formed inside and outside the metal layer. The intensity distribution near the boundary of the layer has been calculated and analyzed. A scheme for the experimental realization of a superposition of Bessel surface plasmon polaritons is suggested. Our study demonstrates that it is feasible to use the superposition of Bessel surface plasmon polaritons as a virtual tip for near-field optical microscopy with a nanoscale resolution.

  5. BIOSMILE: A semantic role labeling system for biomedical verbs using a maximum-entropy model with automatically generated template features

    Directory of Open Access Journals (Sweden)

    Tsai Richard

    2007-09-01

    Full Text Available Abstract Background Bioinformatics tools for automatic processing of biomedical literature are invaluable for both the design and interpretation of large-scale experiments. Many information extraction (IE systems that incorporate natural language processing (NLP techniques have thus been developed for use in the biomedical field. A key IE task in this field is the extraction of biomedical relations, such as protein-protein and gene-disease interactions. However, most biomedical relation extraction systems usually ignore adverbial and prepositional phrases and words identifying location, manner, timing, and condition, which are essential for describing biomedical relations. Semantic role labeling (SRL is a natural language processing technique that identifies the semantic roles of these words or phrases in sentences and expresses them as predicate-argument structures. We construct a biomedical SRL system called BIOSMILE that uses a maximum entropy (ME machine-learning model to extract biomedical relations. BIOSMILE is trained on BioProp, our semi-automatic, annotated biomedical proposition bank. Currently, we are focusing on 30 biomedical verbs that are frequently used or considered important for describing molecular events. Results To evaluate the performance of BIOSMILE, we conducted two experiments to (1 compare the performance of SRL systems trained on newswire and biomedical corpora; and (2 examine the effects of using biomedical-specific features. The experimental results show that using BioProp improves the F-score of the SRL system by 21.45% over an SRL system that uses a newswire corpus. It is noteworthy that adding automatically generated template features improves the overall F-score by a further 0.52%. Specifically, ArgM-LOC, ArgM-MNR, and Arg2 achieve statistically significant performance improvements of 3.33%, 2.27%, and 1.44%, respectively. Conclusion We demonstrate the necessity of using a biomedical proposition bank for training

  6. C-band RISAT-1 imagery for geospatial mapping of cryospheric surface features in the Antarctic environment

    Science.gov (United States)

    Jawak, Shridhar D.; Panditrao, Satej N.; Luis, Alvarinho J.

    2016-05-01

    Cryospheric surface feature classification is one of the widely used applications in the field of polar remote sensing. Precise surface feature maps derived from remotely sensed imageries are the major requirement for many geoscientific applications in polar regions. The present study explores the capabilities of C-band dual polarimetric (HH & HV) SAR imagery from Indian Radar Imaging Satellite (RISAT-1) for land cryospheric surface feature mapping. The study areas selected for the present task were Larsemann Hills and Schirmacher Oasis, East Antarctica. RISAT-1 Fine Resolution STRIPMAP (FRS-1) mode data with 3-m spatial resolution was used in the present research attempt. In order to provide additional context to the amount of information in dual polarized RISAT-1 SAR data, a band HH+HV was introduced to make use of the original two polarizations. In addition to the data calibration, transformed divergence (TD) procedure was performed for class separability analysis to evaluate the quality of the statistics before image classification. For most of the class pairs the TD values were comparable, which indicated that the classes have good separability. Fuzzy and Artificial Neural Network classifiers were implemented and accuracy was checked. Nonparametric classifier Support Vector Machine (SVM) was also used to classify RISAT-1 data with an optimized polarization combination into three land-cover classes consisting of sea ice/snow/ice, rocks/landmass, and lakes/waterbodies. This study demonstrates that C-band FRS1 image mode data from the RISAT-1 mission can be exploited to identify, map and monitor land cover features in the polar regions, even during dark winter period. For better landcover classification and analysis, hybrid polarimetric data (cFRS-1 mode) from RISAT-1, which incorporates phase information, unlike the dual-pol linear (HH, HV) can be used for obtaining better polarization signatures.

  7. Surface modification of droplet polymeric microfluidic devices for the stable and continuous generation of aqueous droplets.

    Science.gov (United States)

    Subramanian, Balamurugan; Kim, Namwon; Lee, Wonbae; Spivak, David A; Nikitopoulos, Dimitris E; McCarley, Robin L; Soper, Steven A

    2011-06-21

    Droplet microfluidics performed in poly(methyl methacrylate) (PMMA) microfluidic devices resulted in significant wall wetting by water droplets formed in a liquid-liquid segmented flow when using a hydrophobic carrier fluid such as perfluorotripropylamine (FC-3283). This wall wetting led to water droplets with nonuniform sizes that were often trapped on the wall surfaces, leading to unstable and poorly controlled liquid-liquid segmented flow. To circumvent this problem, we developed a two-step procedure to hydrophobically modify the surfaces of PMMA and other thermoplastic materials commonly used to make microfluidic devices. The surface-modification route involved the introduction of hydroxyl groups by oxygen plasma treatment of the polymer surface followed by a solution-phase reaction with heptadecafluoro-1,1,2,2-tetrahydrodecyl trichlorosilane dissolved in fluorocarbon solvent FC-3283. This procedure was found to be useful for the modification of PMMA and other thermoplastic surfaces, including polycyclic olefin copolymer (COC) and polycarbonate (PC). Angle-resolved X-ray photoelectron spectroscopy indicated that the fluorination of these polymers took place with high surface selectivity. This procedure was used to modify the surface of a PMMA droplet microfluidic device (DMFD) and was shown to be useful in reducing the wetting problem during the generation of aqueous droplets in a perfluorotripropylamine (FC-3283) carrier fluid and could generate stable segmented flows for hours of operation. In the case of PMMA DMFD, oxygen plasma treatment was carried out after the PMMA cover plate was thermally fusion bonded to the PMMA microfluidic chip. Because the appended chemistry to the channel wall created a hydrophobic surface, it will accommodate the use of other carrier fluids that are hydrophobic as well, such as hexadecane or mineral oils.

  8. Surface second-harmonic generation from coupled spherical plasmonic nanoparticles: Eigenmode analysis and symmetry properties

    Science.gov (United States)

    Butet, Jérémy; Dutta-Gupta, Shourya; Martin, Olivier J. F.

    2014-06-01

    The surface second-harmonic generation from interacting spherical plasmonic nanoparticles building different clusters (symmetric and asymmetric dimers, trimers) is theoretically investigated. The plasmonic eigenmodes of the nanoparticle clusters are first determined using an ab initio approach based on the Green's functions method. This method provides the properties, such as the resonant wavelengths, of the modes sustained by a given cluster. The fundamental and second-harmonic responses of the corresponding clusters are then calculated using a surface integral method. The symmetry of both the linear and nonlinear responses is investigated, as well as their relationship. It is shown that the second-harmonic generation can be significantly enhanced when the fundamental field is such that its second harmonic matches modes with suitable symmetry. The role played by the nanogaps in second-harmonic generation is also underlined. The results presented in this article demonstrate that the properties of the second-harmonic generation from coupled metallic nanoparticles cannot be fully predicted from their linear response only, while, on the other hand, a detailed knowledge of the underlying modal structure can be used to optimize the generation of the second harmonic.

  9. Feature aware Digital Surface Model analysis and generalization based on the 3D Medial Axix Transform

    NARCIS (Netherlands)

    Peters, R.Y.

    2014-01-01

    Modern Digital Surface Models (DSMs) are highly detailed and cover large areas. This brings great advantages for applications such as flood modeling, crisis management and 3D city modeling. Unfor- tunately, and despite recent developments on this subject, current methods are unable to fully take ad-

  10. Persistent small-scale features in maps of the anisotropy of ocean surface velocities

    Science.gov (United States)

    Sen, A.; Arbic, B. K.; Scott, R. B.; Holland, C. L.; Logan, E.; Qiu, B.

    2006-12-01

    Much of the stirring and mixing in the upper ocean is due to geostrophically balanced mesoscale eddies. Ocean general circulation models commonly parameterize eddy effects and can aid in predicting dispersal of materials throughout the ocean or in predicting long-term climate change. Parameterizations of eddy mixing depend on the isotropy of the eddies. Motivated by this, we investigate the isotropy of oceanic mesoscale eddies with seven years of sea surface height data recorded by satellite altimeters. From these data, we determined a sea surface height anomaly, and surface geostrophic velocities u and v in the zonal (east-west) and meridional (north-south) directions, respectively. From the latter two quantities we can calculate zonal and meridional kinetic energies u2 and v2. Integrals of u2 and v2 around latitude bands 10 degrees wide are nearly equal, in contrast with the results of simple beta-plane geostrophic turbulence models, which suggest that zonal motions should predominate. Maps of the quantity u2-v2 (normalized by standard error) show fine-scale structures that persist over times longer than the lifespan of turbulent eddies. Thus the mesoscale eddy field is locally anisotropic almost everywhere. Further investigation into the causes of these small-scale structures is needed and may take advantage of animations of sea surface height, in which quasi- circular, westward-propagating eddies can easily be seen.

  11. Crowned spur gears - Methods for generation and tooth contact analysis. I - Basic concepts, generation of the pinion tooth surface by a plane

    Science.gov (United States)

    Litvin, F. L.; Handschuh, R. F.; Zhang, J.

    1988-01-01

    A topology of crowned spur pinion tooth surface that reduces the level of transmission errors due to misalignment is proposed. The geometry of the deviated pinion tooth surface and regular gear tooth surface, along with tooth contact analysis is discussed. Generation of the deviated pinion tooth surface by a plane whose motion is controlled by a five-degree-of-freedom system is proposed. Numerical results are included and indicate that transmission errors remain low as the gears are misaligned.

  12. The effect of a surface diffraction lattice on the laser generation of light in CdS monocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Tagay, V.A.; Kolbasov, G.Ya.; Snitko, O.V.; Sterligov, V.A.

    1980-01-01

    Laser generation is studied, along with the spectra of amplification of light in laminar CdS monocrystals with a surface diffraction lattice (DR) with excitation by a pulsed nitrogen laser. It is shown that the directivity diagram (DN) of the radiation is formed with the participation of indirect modes of the crystal and has features as compared with samples of CdS without the diffraction lattice; in this the spectrum of radiation is not changed. With radiation the directivity diagram of the amplification of the testing beam it is established that the maximums of amplification correlate according to position and the angular width with the loops of the angular distribution of the intensity of the laser generation in the CdS. It is shown that an increase in the light amplification factor in crystals with a diffraction lattice leads to a reduction in the threshold of laser generation. The conditions for light propagation in crystals with a diffraction lattice are analyzed.

  13. Local changes of work function near rough features on Cu surfaces operated under high external electric field

    Energy Technology Data Exchange (ETDEWEB)

    Djurabekova, Flyura, E-mail: flyura.djurabekova@helsinki.fi; Ruzibaev, Avaz; Parviainen, Stefan [Helsinki Institute of Physics and Department of Physics, University of Helsinki, P.O. Box 43, FI-00014 Helsinki (Finland); Holmström, Eero [Department of Physics, University of Helsinki, P.O. Box 64, FIN-00014 Helsinki (Finland); Department of Earth Sciences, Faculty of Maths and Physical Sciences, UCL Earth Sciences, Gower Street, London WC1E 6BT (United Kingdom); Hakala, Mikko [Department of Physics, University of Helsinki, P.O. Box 64, FIN-00014 Helsinki (Finland)

    2013-12-28

    Metal surfaces operated under high electric fields produce sparks even if they are held in ultra high vacuum. In spite of extensive research on the topic of vacuum arcs, the mystery of vacuum arc origin still remains unresolved. The indications that the sparking rates depend on the material motivate the research on surface response to extremely high external electric fields. In this work by means of density-functional theory calculations we analyze the redistribution of electron density on (100) Cu surfaces due to self-adatoms and in presence of high electric fields from −1 V/nm up to −2 V/nm (−1 to −2 GV/m, respectively). We also calculate the partial charge induced by the external field on a single adatom and a cluster of two adatoms in order to obtain reliable information on charge redistribution on surface atoms, which can serve as a benchmarking quantity for the assessment of the electric field effects on metal surfaces by means of molecular dynamics simulations. Furthermore, we investigate the modifications of work function around rough surface features, such as step edges and self-adatoms.

  14. Phase study of the generated surface plasmon waves in light transmission through a subwavelength aperture

    DEFF Research Database (Denmark)

    Hashemi, Mahdieh; Xiao, Sanshui; Farzad, Mahmood Hosseini

    2014-01-01

    Interference of surface plasmon (SP) waves plays a key role in light transmission through a subwavelength aperture surrounded by groove structures. In order to characterize interference of the hole and groove-generated SP waves, their phase information was carefully investigated using finite...... difference time domain simulations. In a structure with only one groove, constructive interference of the generated SP waves will enhance transmitted light by a factor of 5.4 compared with that of a single hole. Increasing the groove number to 3 in the design, which supports constructive interference of SP...... waves, will enhance the transmission coefficient to 10.5 times that for the single-hole transmission coefficient....

  15. Direct CO(2) laser-based generation of holographic structures on the surface of glass.

    Science.gov (United States)

    Wlodarczyk, Krystian L; Weston, Nicholas J; Ardron, Marcus; Hand, Duncan P

    2016-01-25

    A customized CO(2) laser micromachining system was used for the generation of phase holographic structures directly on the surface of fused silica (HPFS(®)7980 Corning) and Borofloat(®)33 (Schott AG) glass. This process used pulses of duration 10µs and nominal wavelength 10.59µm. The pulse energy delivered to the glass workpiece was controlled by an acousto-optic modulator. The laser-generated structures were optically smooth and crack free. We demonstrated their use as diffractive optical elements (DOEs), which could be exploited as anti-counterfeiting markings embedded into valuable glass-made components and products.

  16. Surface acoustic wave opto-mechanical oscillator and frequency comb generator.

    Science.gov (United States)

    Savchenkov, A A; Matsko, A B; Ilchenko, V S; Seidel, D; Maleki, L

    2011-09-01

    We report on realization of an efficient triply resonant coupling between two long lived optical modes and a high frequency surface acoustic wave (SAW) mode of the same monolithic crystalline whispering gallery mode resonator. The coupling results in an opto-mechanical oscillation and generation of a monochromatic SAW. A strong nonlinear interaction of this mechanical mode with other equidistant SAW modes leads to mechanical hyperparametric oscillation and generation of a SAW pulse train and associated frequency comb in the resonator. We visualized the comb by observing the modulation of the light escaping the resonator.

  17. Features of surface enhanced Raman scattering in the systems with «hot spots»

    Directory of Open Access Journals (Sweden)

    Solovyeva E.V.

    2017-01-01

    Full Text Available In this work we demonstrate the features of SERS on the substrates with «hot spots» on the example of system «diaminostilbene - colloidal silver». We found that «hot spots» forming on aggregated nanoparticles exist on the metal substrates only at low concentration of ligand. This effect caused by the gradual filling of first monolayer by adsorbate molecules. Significantly higher enhancement factor is obtained for substrates with «hot spots», for which the participation of resonance processes in the formation of SERS signal is revealed also.

  18. Features of surface enhanced Raman scattering in the systems with «hot spots»

    Science.gov (United States)

    Solovyeva, E. V.; Khazieva, D. A.; Denisova, A. S.

    2016-12-01

    In this work we demonstrate the features of SERS on the substrates with «hot spots» on the example of system «diaminostilbene - colloidal silver». We found that «hot spots» forming on aggregated nanoparticles exist on the metal substrates only at low concentration of ligand. This effect caused by the gradual filling of first monolayer by adsorbate molecules. Significantly higher enhancement factor is obtained for substrates with «hot spots», for which the participation of resonance processes in the formation of SERS signal is revealed also.

  19. Field emission study from an array of hierarchical micro protrusions on stainless steel surface generated by femtosecond pulsed laser irradiation

    Science.gov (United States)

    Singh, A. K.; Suryawanshi, Sachin R.; More, M. A.; Basu, S.; Sinha, Sucharita

    2017-02-01

    This paper reports our results on femtosecond (fs) pulsed laser induced surface micro/nano structuring of stainless steel 304 (SS 304) samples and their characterization in terms of surface morphology, formed material phases on laser irradiation and field emission studies. Our investigations reveal that nearly uniform and dense array of hierarchical micro-protrusions (density: ∼5.6 × 105 protrusions/cm2) is formed upon laser treatment. Typical tip diameters of the generated protrusions are in the range of 2-5 μm and these protrusions are covered with submicron sized features. Grazing incidence X-ray diffraction (GIXRD) analysis of the laser irradiated sample surface has shown formation mainly of iron oxides and cementite (Fe3C) phases in the treated region. These laser micro-structured samples have shown good field emission properties such as low turn on field (∼4.1 V/μm), high macroscopic field enhancement factor (1830) and stable field emission current under ultra high vacuum conditions.

  20. Structural Reorganization and Fibrinogen Adsorption Behaviors on the Polyrotaxane Surfaces Investigated by Sum Frequency Generation Spectroscopy.

    Science.gov (United States)

    Ge, Aimin; Seo, Ji-Hun; Qiao, Lin; Yui, Nobuhiko; Ye, Shen

    2015-10-14

    Polyrotaxanes, such as supramolecular assemblies with methylated α-cyclodextrins (α-CDs) as host molecules noncovalently threaded on the linear polymer backbone, are promising materials for biomedical applications because they allow adsorbed proteins possessing a high surface flexibility as well as control of the cellular morphology and adhesion. To provide a general design principle for biomedical materials, we examined the surface reorganization behaviors and adsorption conformations of fibrinogen on the polyrotaxane surfaces with comparison to several random copolymers by sum frequency generation (SFG) vibrational spectroscopy. We showed that the polyrotaxane (OMe-PRX-PMB) with methylated α-CDs as the host molecule exhibited unique surface structures in an aqueous environment. The hydrophobic interaction between the methoxy groups of the methylated α-CD molecules and methyl groups of the n-butyl methacrylate (BMA) side chains may dominate the surface restructuring behavior of the OMe-PRX-PMB. The orientation analysis revealed that the orientation of the fibrinogen adsorbed on the OMe-PRX-PMB surface is close to a single distribution, which is different from the adsorption behaviors of fibrinogen on other polyrotaxane or random copolymer surfaces.

  1. Land cover effects on thresholds for surface runoff generation in Eastern Madagascar

    Science.gov (United States)

    van Meerveld, Ilja H. J.; Prasad Ghimire, Chandra; Zwartendijk, Bob W.; Ravelona, Maafaka; Lahitiana, Jaona; Bruijnzeel, L. Adrian

    2016-04-01

    Reforestation and natural regrowth in the tropics are promoted for a wide range of benefits, including carbon sequestration, land rehabilitation and streamflow regulation. However, their effects on runoff generation mechanisms and streamflow are still poorly understood. Evaporative losses (transpiration and interception) likely increase with forest regrowth, while infiltration rates are expected to increase and surface runoff occurrence is, therefore, expected to decrease. As part of a larger project investigating the effects of land use on hydrological processes in upland Eastern Madagascar, this presentation reports on a comparison of the thresholds for surface runoff generation at a degraded grassland site, a young secondary forest site (5-7 years; LAI 1.83) and a mature secondary forest site (ca. 20 years; LAI 3.39). Surface runoff was measured on two (young and mature secondary forest) or three (degraded site) 3 m by 10 m plots over a one-year period (October 2014-September 2015). Soil moisture was measured at four (degraded site) to six depths (both forests), while perched groundwater levels were measured in piezometers installed at 30 cm below the soil surface. Soil hydraulic conductivity was measured in situ at the surface and at 10-20 and 20-30 cm depths at three locations in each plot. Porosity, moisture content at field capacity and bulk density were determined from soil cores taken at 2.5-7.5, 12.5-17.5 and 22.5-27.5 cm depth. The porosity and texture of the different plots were comparable. The hydraulic conductivity of the soil differed between the different land uses and declined sharply at 20-30 cm below the soil surface. Total surface runoff during the study period was 11% of incident rainfall at the degraded site vs. 2% for the two secondary forest sites. Maximum monthly runoff coefficients were 22%, 3.5% and 2.7% for the degraded site, the young forest site and the mature forest site, respectively, but individual event runoff coefficients could be

  2. Tuning anatase and rutile phase ratios and nanoscale surface features by anodization processing onto titanium substrate surfaces.

    Science.gov (United States)

    Roach, M D; Williamson, R S; Blakely, I P; Didier, L M

    2016-01-01

    Both the anatase (A) and rutile (R) phases of titanium oxide have shown enhanced antimicrobial and bioactivity levels but the specific A/R phase ratio needed for the best results is still unknown. In this study titanium samples were anodized to produce specific ratios of anatase and rutile phases within the oxide layers. Specific ratios produced included maximum A minimum R, minimum A maximum R, 50% A 50% R, minimum A minimum R, and a non-anodized titanium control group. Samples were characterized for phase distributions within the oxide layers, surface porosity, corrosion resistance, and bioactivity. Results indicated the targeted phase ratios were reproducibly achieved during the anodization process. Samples containing the highest levels of anatase showed the largest individual pore sizes, but a lower overall percent porosity value compared to samples containing higher rutile levels. EBSD examination of the anodized layer cross-sections provided valuable new spatial information on the distribution of anatase and rutile phases within the anodized layers. Highly porous oxide layers showed significantly higher corrosion rates compared to non-anodized titanium, but no significant differences were shown in the icorr values between samples containing primarily anatase phase, samples containing primarily rutile phase, and samples containing an approximate 50:50 mixture of the two phases. Minimum A minimum R samples showed substantially less porosity compared to the other anodization groups, a significantly lower oxide thickness, and comparable corrosion rates to non-anodized titanium. All samples within the study showed apatite production in simulated body fluid within the seven day test period indicating enhanced bioactivity.

  3. Feature-resolved computational and analytical study of laminar drag reduction by superhydrophobic surfaces

    Science.gov (United States)

    Li, Yixuan; Alame, Karim; Mahesh, Krishnan

    2017-05-01

    Direct numerical simulations are used to study the drag reduction by superhydrophobic surfaces in laminar channel flow. Resolved multiphase simulations using the volume of fluid methodology are performed to study the effects of groove geometry, interface shear rate, and meniscus penetration independently. An analytical solution for the flow in a laminar channel with a grooved surface with a gas pocket within is obtained. The solution accounts for both the groove geometry and the trapped fluid properties, and shows good agreement with simulation results. The solution is used to propose a scaling law that collapses data across fully wetted to fully gas-filled regimes. The trapped gas is simulated as both flat and meniscal interfaces. The drag reduction initially increases with interface deflection into the groove and then decreases for large deflections as the interface velocity approaches zero due to the proximity to the bottom of the groove.

  4. 1DTempPro V2: new features for inferring groundwater/surface-water exchange

    Science.gov (United States)

    Koch, Franklin W.; Voytek, Emily B.; Day-Lewis, Frederick D.; Healy, Richard W.; Briggs, Martin; Lane, Jr., John W.; Werkema, Dale

    2016-01-01

    A new version of the computer program 1DTempPro extends the original code to include new capabilities for (1) automated parameter estimation, (2) layer heterogeneity, and (3) time-varying specific discharge. The code serves as an interface to the U.S. Geological Survey model VS2DH and supports analysis of vertical one-dimensional temperature profiles under saturated flow conditions to assess groundwater/surface-water exchange and estimate hydraulic conductivity for cases where hydraulic head is known.

  5. Preparation of porous polymer monoliths featuring enhanced surface coverage with gold nanoparticles

    KAUST Repository

    Lv, Yongqin

    2012-10-01

    A new approach to the preparation of porous polymer monoliths with enhanced coverage of pore surface with gold nanoparticles has been developed. First, a generic poly(glycidyl methacrylate-co-ethylene dimethacrylate) monolith was reacted with cystamine followed by the cleavage of its disulfide bonds with tris(2-carboxylethyl)phosphine, which liberated the desired thiol groups. Dispersions of gold nanoparticles with sizes varying from 5 to 40. nm were then pumped through the functionalized monoliths. The materials were then analyzed using both energy dispersive X-ray spectroscopy and thermogravimetric analysis. We found that the quantity of attached gold was dependent on the size of nanoparticles, with the maximum attachment of more than 60. wt% being achieved with 40. nm nanoparticles. Scanning electron micrographs of the cross sections of all the monoliths revealed the formation of a non-aggregated, homogenous monolayer of nanoparticles. The surface of the bound gold was functionalized with 1-octanethiol and 1-octadecanethiol, and these monolithic columns were used successfully for the separations of proteins in reversed phase mode. The best separations were obtained using monoliths modified with 15, 20, and 30. nm nanoparticles since these sizes produced the most dense coverage of pore surface with gold. © 2012 Elsevier B.V.

  6. Wide-field surface plasmon microscopy of nano- and microparticles: features, benchmarking, limitations, and bioanalytical applications

    Science.gov (United States)

    Nizamov, Shavkat; Scherbahn, Vitali; Mirsky, Vladimir M.

    2017-05-01

    Detection of nano- and micro-particles is an important task for chemical analytics, food industry, biotechnology, environmental monitoring and many other fields of science and industry. For this purpose, a method based on the detection and analysis of minute signals in surface plasmon resonance images due to adsorption of single nanopartciles was developed. This new technology allows one a real-time detection of interaction of single nano- and micro-particles with sensor surface. Adsorption of each nanoparticle leads to characteristic diffraction image whose intensity depends on the size and chemical composition of the particle. The adsorption rate characterizes volume concentration of nano- and micro-particles. Large monitored surface area of sensor enables a high dynamic range of counting and to a correspondingly high dynamic range in concentration scale. Depending on the type of particles and experimental conditions, the detection limit for aqueous samples can be below 1000 particles per microliter. For application of method in complex media, nanoparticle images are discriminated from image perturbations due to matrix components. First, the characteristic SPRM images of nanoparticles (templates) are collected in aqueous suspensions or spiked real samples. Then, the detection of nanoparticles in complex media using template matching is performed. The detection of various NPs in consumer products like cosmetics, mineral water, juices, and wines was shown at sub-ppb level. The method can be applied for ultrasensitive detection and analysis of nano- and micro-particles of biological (bacteria, viruses, endosomes), biotechnological (liposomes, protein nanoparticles for drug delivery) or technical origin.

  7. Plume and surface feature structure and compositional effects on Europa's global exosphere: Preliminary Europa mission predictions

    Science.gov (United States)

    Teolis, B. D.; Wyrick, D. Y.; Bouquet, A.; Magee, B. A.; Waite, J. H.

    2017-03-01

    A Europa plume source, if present, may produce a global exosphere with complex spatial structure and temporal variability in its density and composition. To investigate this interaction we have integrated a water plume source containing multiple organic and nitrile species into a Europan Monte Carlo exosphere model, considering the effect of Europa's gravity in returning plume ejecta to the surface, and the subsequent spreading of adsorbed and exospheric material by thermal desorption and re-sputtering across the entire body. We consider sputtered, radiolytic and potential plume sources, together with surface adsorption, regolith diffusion, polar cold trapping, and re-sputtering of adsorbed materials, and examine the spatial distribution and temporal evolution of the exospheric density and composition. These models provide a predictive basis for telescopic observations (e.g. HST, JWST) and planned missions to the Jovian system by NASA and ESA. We apply spacecraft trajectories to our model to explore possible exospheric compositions which may be encountered along proposed flybys of Europa to inform the spatial and temporal relationship of spacecraft measurements to surface and plume source compositions. For the present preliminary study, we have considered four cases: Case A: an equatorial flyby through a sputtered only exosphere (no plumes), Case B: a flyby over a localized sputtered 'macula' terrain enriched in non-ice species, Case C: a south polar plume with an Enceladus-like composition, equatorial flyby, and Case D: a south polar plume, flyby directly through the plume.

  8. Surface Ice Velocity Retrieval From MOA Based On NCC Feature Tracking

    Science.gov (United States)

    Li, T.; Liu, Y.; Cheng, X.

    2016-12-01

    The velocity of glacier in Antarctica is a fundamental parameter to ice dynamics and projection of sea level rise, and it is as well the key indicator of global climate change. COSI-Corr, an extension of ENVI software, was employed to acquire the horizontal velocity of ice flows throughout the whole Antarctica continent from 2003-2004 and 2008-2009 MOA (MODIS Mosaic of Antarctica) compiled by NSIDC. However, conventional tracking methods severely suffer from spurious matching resulting from ice surface's variation, illumination condition, inappropriate window size etc. So it is indispensable to correct the initial output field contaminated by noises before extracting valuable information. Usually, the low-SNR areas, which denote quite poor quality, are filtered out directly based on some roles of thumb. Here we have some experiments to test performance of FFT (Fast Fourier Transform) and SVD (Singularity Value Decomposition) of optimizing the estimation by cutting image into overlapped tiles. Validation was conducted by comparing the final result with respect to MEaSUREs in typical flow areas including inland stream and ice shelves. The primitive results shows that both methods can reduce RMSE to an extent of 20% 40% but FFT performs more robust. Our result shows that MOA datasets, which highlight true surface morphology, have potential for continental ice surface velocity's retrieval.

  9. Joint Beamforming and Feature Detection for Enhanced Visualization of Spinal Bone Surfaces in Ultrasound Images

    CERN Document Server

    Mehdizadeh, Saeed; Kiss, Gabriel; Johansen, Tonni F; Holm, Sverre

    2016-01-01

    We propose a framework for extracting the bone surface from B-mode images employing the eigenspace minimum variance (ESMV) beamformer and a ridge detection method. We show that an ESMV beamformer with a rank-1 signal subspace can preserve the bone anatomy and enhance the edges, despite an image which is less visually appealing due to some speckle pattern distortion. The beamformed images are post-processed using the phase symmetry (PS) technique. We validate this framework by registering the ultrasound images of a vertebra (in a water bath) against the corresponding Computed Tomography (CT) dataset. The results show a bone localization error in the same order of magnitude as the standard delay-and-sum (DAS) technique, but with approximately 20% smaller standard deviation (STD) of the image intensity distribution around the bone surface. This indicates a sharper bone surface detection. Further, the noise level inside the bone shadow is reduced by 60%. In in-vivo experiments, this framework is used for imaging ...

  10. Determine electric field directions at semiconductor surfaces by femtosecond frequency domain interferometric second harmonic (FDISH) generation

    Science.gov (United States)

    Nelson, C. A.; Zhu, X.-Y.

    2016-10-01

    Optical excitations at semiconductor surfaces or interfaces are accompanied by transient interfacial electric fields due to charge redistribution or transfer. While such transient fields may be probed by time-resolved second harmonic generation (TR-SHG), it is difficult to determine the field direction, which is invaluable to unveiling the underlying physics. Here we apply a time-resolved frequency domain interferometric second harmonic (TR-FDISH) generation technique to determine the phase relationship between the SH field emitted from bulk GaAs(1 0 0) and the transient SH field from the space charge region. The interference between these two SH fields allow us to unambiguously determine the directions of transient electric fields. Since SH fields from a static bulk contribution and a changing electric field contribution are present at most semiconductor surfaces or interfaces under optical excitation, the TR-FDISH technique is of general significance to probing the dynamics of interfacial charge transfer/redistribution.

  11. UNSTEADY FREE-SURFACE WAVES GENERATED BY BODIES IN A VISCOUS FLUID

    Institute of Scientific and Technical Information of China (English)

    LU Dong-qiang

    2004-01-01

    The interaction of laminar flows with free sur face waves generated by submerged bodies in an incompressible viscous fluid of infinite depth is investigated analytically.The analysis is based on the linearized Navier-Stokes equations for disturbed flows. The kinematic and dynamic boundary conditions are linearized for the small amplitude free-surface waves, and the initial values of the flow are taken to be those of the steady state cases. The submerged bodies are mathematically represented by fundamental singularities of viscous flows. The asymptotic representations for unsteady free-surface waves produced by the Stokeslets and Oseenlets are derived analytically. It is found that the unsteady waves generated by a body consist of steady-state and transient responses.As time tends to infinity, the transient waves vanish due to the presence of a viscous decay factor. Thus. an ultimate steady state can be attained.

  12. Characteristics and realization of the second generation surface acoustic wave's wavelet device

    Institute of Scientific and Technical Information of China (English)

    Wen Changbao; Zhu Changchun; Lu Wenke; Liu Qinghong; Liu Junhua

    2006-01-01

    To overcome the bulk acoustic wave (BAW), the triple transit signals and the discontinuous frequency band in the first generation surface acoustic wave's (FGSAW's) wavelet device, the full transfer multistrip coupler (MSC) is applied to implement wavelet device, and a novel structure of the second generation surface acoustic wave's (SGSAW's) wavelet device is proposed. In the SGSAW's wavelet device, the BAW is separated and eliminated in different acoustic propagating tracks, and the triple transit signal is suppressed. For arbitrary wavelet scale device, the center frequency is three times the radius of frequency band, which ensures that the frequency band of the SGSAW's wavelet device is continuous, and avoids losing signals caused by the discontinuation of frequency band. Experimental result confirms that the BAW suppression, ripples in band, receiving loss and insertion loss of the SGSAW's wavelet device are remarkably improved compared with those of the FGSAW's wavelet device.

  13. Laser Generation of Surface Waves on Cylinder with a Slow Coating

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shi-Gong; HU Wen-Xiang

    2008-01-01

    @@ An analytical model of acoustic field excited by a pulsed-laser line source on a coated cylinder is presented.Surface wave dispersive behaviours for a cylinder with a slow coating are analysed and compared with that of a bare cylinder.Based on this analysis, the laser-generated transient response of the perturbed Rayleigh wave and the higher modes of steel cylinder with a zinc coating are calculated from the model using residue theory and FFT technique.The theoretical result from the superposed waveform of the perturbed Rayleigh wave and higher modes agree well with the waveform obtained in experiment.The results show that the model and numerical method provide a useful technique for quantitatively characterizing coating parameters of coated cylinder by the laser generated surface waves.

  14. Real-Space Imaging of Carrier Dynamics of Materials Surfaces by Second-Generation Four-Dimensional Scanning Ultrafast Electron Microscopy

    KAUST Repository

    Sun, Jingya

    2015-09-14

    In the fields of photocatalysis and photovoltaics, ultrafast dynamical processes, including carrier trapping and recombination on material surfaces, are among the key factors that determine the overall energy conversion efficiency. A precise knowledge of these dynamical events on the nanometer (nm) and femtosecond (fs) scales was not accessible until recently. The only way to access such fundamental processes fully is to map the surface dynamics selectively in real space and time. In this study, we establish a second generation of four-dimensional scanning ultrafast electron microscopy (4D S-UEM) and demonstrate the ability to record time-resolved images (snapshots) of material surfaces with 650 fs and ∼5 nm temporal and spatial resolutions, respectively. In this method, the surface of a specimen is excited by a clocking optical pulse and imaged using a pulsed primary electron beam as a probe pulse, generating secondary electrons (SEs), which are emitted from the surface of the specimen in a manner that is sensitive to the local electron/hole density. This method provides direct and controllable information regarding surface dynamics. We clearly demonstrate how the surface morphology, grains, defects, and nanostructured features can significantly impact the overall dynamical processes on the surface of photoactive-materials. In addition, the ability to access two regimes of dynamical probing in a single experiment and the energy loss of SEs in semiconductor-nanoscale materials will also be discussed.

  15. Sensitivity Analysis of Entropy Generation in Nanofluid Flow inside a Channel by Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Bijan Darbari

    2016-02-01

    Full Text Available Nanofluids can afford excellent thermal performance and have a major role in energy conservation aspect. In this paper, a sensitivity analysis has been performed by using response surface methodology to calculate the effects of nanoparticles on the entropy generation. For this purpose, the laminar forced convection of Al2O3-water nanofluid flow inside a channel is considered. The total entropy generation rates consist of the entropy generation rates due to heat transfer and friction loss are calculated by using velocity and temperature gradients. The continuity, momentum and energy equations have been solved numerically using a finite volume method. The sensitivity of the entropy generation rate to different parameters such as the solid volume fraction, the particle diameter, and the Reynolds number is studied in detail. Series of simulations were performed for a range of solid volume fraction 0 ≤ ϕ ≤ 0.05 , particle diameter 30  nm ≤ d p ≤ 90 ​ nm , and the Reynolds number 200 ≤ Re ≤ 800. The results showed that the total entropy generation is more sensitive to the Reynolds number rather than the nanoparticles diameter or solid volume fraction. Also, the magnitude of total entropy generation, which increases with increase in the Reynolds number, is much higher for the pure fluid rather than the nanofluid.

  16. Effects of different blasting materials on charge generation and decay on titanium surface after sandblasting.

    Science.gov (United States)

    Guo, Cecilia Yan; Hong Tang, Alexander Tin; Hon Tsoi, James Kit; Matinlinna, Jukka Pekka

    2014-04-01

    It has been reported that sandblasting titanium with alumina (Al2O3) powder could generate a negative electric charge on titanium surface. This has been proven to promote osteoblast activities and possibly osseointegration. The purpose of this pilot study was to investigate the effects of different blasting materials, in terms of the grit sizes and electro-negativity, on the generation of a negative charge on the titanium surface. The aim was also to make use of these results to deduct the underlying mechanism of charge generation by sandblasting. Together 60 c.p. 2 titanium plates were machine-cut and polished for sandblasting, and divided into 6 groups with 10 plates in each. Every plate in the study groups was sandblasted with one of the following 6 powder materials: 110µm Al2O3 grits, 50µm Al2O3 grits, 150-300µm glass beads, 45-75µm glass beads, 250µm Al powder and 44µm Al powder. The static voltage on the surface of every titanium plate was measured immediately after sandblasting. The static voltages of the titanium plates were recorded and processed using statistical analysis. The results suggested that only sandblasting with 45-75µm glass beads generated a positive charge on titanium, while using all other blasting materials lead to a negative charge. Furthermore, blasting grits of the same powder material but of different sizes might lead to different amount and polarity of the charges. This triboelectric effect is likely to be the main mechanism for charge generation through sandblasting.

  17. Small-Scale Morphological Features on a Solid Surface Processed by High-Pressure Abrasive Water Jet.

    Science.gov (United States)

    Kang, Can; Liu, Haixia

    2013-08-14

    Being subjected to a high-pressure abrasive water jet, solid samples will experience an essential variation of both internal stress and physical characteristics, which is closely associated with the kinetic energy attached to the abrasive particles involved in the jet stream. Here, experiments were performed, with particular emphasis being placed on the kinetic energy attenuation and turbulent features in the jet stream. At jet pressure of 260 MPa, mean velocity and root-mean-square (RMS) velocity on two jet-stream sections were acquired by utilizing the phase Doppler anemometry (PDA) technique. A jet-cutting experiment was then carried out with Al-Mg alloy samples being cut by an abrasive water jet. Morphological features and roughness on the cut surface were quantitatively examined through scanning electron microscopy (SEM) and optical profiling techniques. The results indicate that the high-pressure water jet is characterized by remarkably high mean flow velocities and distinct velocity fluctuations. Those irregular pits and grooves on the cut surfaces indicate both the energy attenuation and the development of radial velocity components in the jet stream. When the sample is positioned with different distances from the nozzle outlet, the obtained quantitative surface roughness varies accordingly. A descriptive model highlighting the behaviors of abrasive particles in jet-cutting process is established in light of the experimental results and correlation analysis.

  18. Small-Scale Morphological Features on a Solid Surface Processed by High-Pressure Abrasive Water Jet

    Directory of Open Access Journals (Sweden)

    Can Kang

    2013-08-01

    Full Text Available Being subjected to a high-pressure abrasive water jet, solid samples will experience an essential variation of both internal stress and physical characteristics, which is closely associated with the kinetic energy attached to the abrasive particles involved in the jet stream. Here, experiments were performed, with particular emphasis being placed on the kinetic energy attenuation and turbulent features in the jet stream. At jet pressure of 260 MPa, mean velocity and root-mean-square (RMS velocity on two jet-stream sections were acquired by utilizing the phase Doppler anemometry (PDA technique. A jet-cutting experiment was then carried out with Al-Mg alloy samples being cut by an abrasive water jet. Morphological features and roughness on the cut surface were quantitatively examined through scanning electron microscopy (SEM and optical profiling techniques. The results indicate that the high-pressure water jet is characterized by remarkably high mean flow velocities and distinct velocity fluctuations. Those irregular pits and grooves on the cut surfaces indicate both the energy attenuation and the development of radial velocity components in the jet stream. When the sample is positioned with different distances from the nozzle outlet, the obtained quantitative surface roughness varies accordingly. A descriptive model highlighting the behaviors of abrasive particles in jet-cutting process is established in light of the experimental results and correlation analysis.

  19. The role of whole blood in thrombin generation in contact with various titanium surfaces.

    Science.gov (United States)

    Thor, Andreas; Rasmusson, Lars; Wennerberg, Ann; Thomsen, Peter; Hirsch, Jan-Michael; Nilsson, Bo; Hong, Jaan

    2007-02-01

    Understanding of the thrombotic response (activation of the intrinsic coagulation system followed by platelet activation) from blood components upon contact with a titanium dental implant is important and not fully understood. The aims of this study were to evaluate: (1) the thrombogenic response of whole blood, platelet-rich plasma (PRP) and platelet-poor plasma (PPP) in contact with a highly thrombogenic surface as titanium, (2) the thrombogenic response of clinically used surfaces as hydroxyapatite (HA), machined titanium (mTi), TiO2 grit-blasted titanium (TiOB) and fluoride ion-modified grit-blasted titanium (TiOB-F). An in vitro slide chamber model, furnished with heparin, was used in which whole blood, PRP or PPP came in contact with slides of the test surfaces. After incubation (60 min rotation at 22 rpm in a 37 degrees C water bath), blood/plasma was mixed with EDTA or citrate, further centrifuged at +4 degrees C (2200 g at 10 min). Finally, plasma was collected pending analysis. Whole blood in contact with Ti alloy resulted in the binding of platelets to the material surface and in the generation of thrombin-antithrombin (TAT) complexes. With whole blood TAT levels increased 1000-fold compared with PRP and PPP, in which both almost no increase of TAT could be detected. In addition, the platelet activation showed a similar pattern with a 15-fold higher release of beta-TG in whole blood. In the in vitro chamber model with the clinically relevant materials, the fluoride-modified surface (TiOB-F) showed pronounced TAT generation compared with TiOB, mTi and HA. Similar results were achieved for platelet consumption and activation markers of the intrinsic coagulation system. Taken together these results implicate first that whole blood is necessary for sufficient thrombin generation and platelet activation during placement of implants. Second, a fluoride ion modification seems to augment the thrombogenic properties of titanium.

  20. Elasticity estimates from images of crawling waves generated by miniature surface sources.

    Science.gov (United States)

    Partin, Alexander; Hah, Zaegyoo; Barry, Christopher T; Rubens, Deborah J; Parker, Kevin J

    2014-04-01

    We describe a surface-based approach to the generation of shear wave interference patterns, called crawling waves (CrW), within a medium and derive local estimates of biomechanical properties of tissue. In previous experiments, elongated bars operating as vibration sources were used to generate CrW propagation in samples. In the present study, however, a pair of miniature circular vibration sources was applied to the overlying skin to generate the CrW within the medium. The shape and position of the miniature sources make this configuration more applicable for in vivo implementation. A modified ultrasound imaging system is used to display the CrW propagation. A shear speed mapping algorithm is developed using a detailed analysis of the CrW. The proposed setup is applied to several biomaterials including a homogeneous phantom, an inhomogeneous phantom and an ex vivo human liver. The data are analyzed using the mapping algorithm to reveal the biomechanical properties of the biomaterials.

  1. Study of Methods to Build Drawing Features on Complex Curved Surface%复杂曲面上构建图样特征的方法研究

    Institute of Scientific and Technical Information of China (English)

    王睿

    2012-01-01

    基于CAXA制造工程师软件中线面映射的功能,从实际应用出发,探讨了在复杂曲面上构建图样特征的方法,以便为在复杂曲面上加工图样打下基础,为后续刀具轨迹的生成做好准备。%Based on the function of line side mapping in the software of CAM manufacturing engineers, this paper starts from reality, and discusses the methods for building drawing feature on complex curved surface, so that it can lay the basis for processing drawmg g& prepared for the generation of the subsequent tool path.

  2. Near-surface gas mapping studies of salt geologic features at Weeks Island and other sites

    Energy Technology Data Exchange (ETDEWEB)

    Molecke, M.A. [Sandia National Lab., Albuquerque, NM (United States); Carney, K.R.; Autin, W.J.; Overton, E.B. [Louisiana State Univ., Baton Rouge, LA (United States)

    1996-10-01

    Field sampling and rapid gas analysis techniques were used to survey near-surface soil gases for geotechnical diagnostic purposes at the Weeks Island Strategic Petroleum Reserve (SPR) site and other salt dome locations in southern Louisiana. This report presents the complete data, results and interpretations obtained during 1995. Weeks Island 1994 gas survey results are also briefly summarized; this earlier study did not find a definitive correlation between sinkhole No. 1 and soil gases. During 1995, several hundred soil gas samples were obtained and analyzed in the field by gas chromatography, for profiling low concentrations and gas anomalies at ppm to percent levels. The target gases included hydrogen, methane, ethane and ethylene. To supplement the field data, additional gas samples were collected at various site locations for laboratory analysis of target gases at ppb levels. Gases in the near-surface soil originate predominantly from the oil, from petrogenic sources within the salt, or from surface microbial activity. Surveys were conducted across two Weeks Island sinkholes, several mapped anomalous zones in the salt, and over the SPR repository site and its perimeter. Samples were also taken at other south Louisiana salt dome locations for comparative purposes. Notable results from these studies are that elevated levels of hydrogen and methane (1) were positively associated with anomalous gassy or shear zones in the salt dome(s) and (2) are also associated with suspected salt fracture (dilatant) zones over the edges of the SPR repository. Significantly elevated areas of hydrogen, methane, plus some ethane, were found over anomalous shear zones in the salt, particularly in a location over high pressure gas pockets in the salt, identified in the mine prior to SPR operations. Limited stable isotope ratio analyses, SIRA, were also conducted and determined that methane samples were of petrogenic origin, not biogenic.

  3. Percentage Contributions from Atmospheric and Surface Features to Computed Brightness Temperatures

    Science.gov (United States)

    Jackson, G. S.

    2006-12-01

    Over the past few years, there has become an increasing interest in the use of millimeter-wave (mm-wave) and sub-millimeter-wave (submm-wave) radiometer observations to investigate the properties of ice particles in clouds. Passive radiometric channels respond to both the integrated particle mass throughout the volume and field of view, and to the amount, location, and size distribution of the frozen (and liquid) particles with the sensitivity varying for different frequencies and hydrometeor types. One methodology used since the 1960's to discern the relationship between the physical state observed and the brightness temperature (TB) is through the temperature weighting function profile. In this research, the temperature weighting function concept is exploited to analyze the sensitivity of various characteristics of the cloud profile, such as relative humidity, ice water path, liquid water path, and surface emissivity. In our numerical analysis, we compute the contribution (in Kelvin) from each of these cloud and surface characteristics, so that the sum of these various parts equals the computed TB. Furthermore, the percentage contribution from each of these characteristics is assessed. There is some intermingling/contamination of the contributions from various components due to the integrated nature of passive observations and the absorption and scattering between the vertical layers, but all in all the knowledge gained is useful. This investigation probes the sensitivity over several cloud classifications, such as cirrus, blizzards, light snow, anvil clouds, and heavy rain. The focus is on mm-wave and submm-wave frequencies, however discussions of the effects of cloud variations to frequencies as low as 10 GHz and up to 874 GHz will also be presented. The results show that nearly 60% of the TB value at 89 GHz comes from the earth's surface for even the heaviest blizzard snow rates. On the other hand, a significant percentage of the TB value comes from the snow

  4. Monitoring surface geothermal features using time series of aerial and ground-based photographs

    Science.gov (United States)

    Bromley, C.; van Manen, S. M.; Graham, D.

    2010-12-01

    Geothermal systems are of high conservation and scientific value and monitoring of these is an important management tool to assess natural variations and changes resulting from development and utilization. This study examines time series of aerial and ground-based photographs of geothermal areas within the Taupo Volcanic Zone, New Zealand. A time series of aerial photographs from 1946-2007 of the Broadlands Road Scenic Reserve (Taupo, New Zealand) highlights large changes to this small area as the result of the start of geothermal fluid production for the nearby Wairakei power plant in 1958 and other causes. Prior to the opening of the plant the area was not geothermally active, but expansion of steam zones due to pressure drawdown has resulted in significant thermal changes in the subsurface. These subsurface thermal changes are evident in the aerial photographs as the appearance of hydrothermal eruption craters and areas of thermal bare ground, which are too hot for vegetation to grown on. In addition, in the late 1960’s thermotolerant vegetation started to establish itself in the adjacent area. Changes in the surface area covered by each of these, reflect changes in the geothermal system as well as changes in management (e.g. exclusion of livestock), and a time series of these changes has been produced using ArcMap™. Monthly photographs of surface geothermal expressions in the Rotorua area show changes in colour and size of chloride springs with time. Colour and size changes are difficult to quantify due to varying exposure settings, weather conditions, and vantage points. However, these qualitative descriptions can be combined with quantitative time series such as temperature measurements, to provide better insight into surface changes that have occurred at this geothermal field. This study highlights the value of both qualitative and quantitative data that can be obtained from time series of photographs, including photographs that were obtained before the

  5. Surface deformations and wave generation by wind blowing over a viscous liquid

    Science.gov (United States)

    Paquier, A.; Moisy, F.; Rabaud, M.

    2015-12-01

    We investigate experimentally the early stage of the generation of waves by a turbulent wind at the surface of a viscous liquid. The spatio-temporal structure of the surface deformation is analyzed by the optical method Free Surface Synthetic Schlieren, which allows for time-resolved measurements with a micrometric accuracy. Because of the high viscosity of the liquid, the flow induced by the turbulent wind in the liquid remains laminar, with weak surface drift velocity. Two regimes of deformation of the liquid-air interface are identified. In the first regime, at low wind speed, the surface is dominated by rapidly propagating disorganized wrinkles, elongated in the streamwise direction, which correspond to the surface response to the pressure fluctuations advected by the turbulent airflow. The amplitude of these deformations increases approximately linearly with wind velocity and are essentially independent of the fetch (distance along the channel). Above a threshold in wind speed, we observe the growth of well defined gravity-capillary waves with crests nearly perpendicular to the wind direction. In this second regime, the wave amplitude increases with wind speed but far more quickly than in the first regime.

  6. Influence of electropolishing current densities on sulfur generation at niobium surface

    Energy Technology Data Exchange (ETDEWEB)

    Tyagi, P.V., E-mail: tyagipv@ornl.gov [The Graduate University for Advanced Studies, Tsukuba, Ibaraki (Japan); Nishiwaki, M.; Noguchi, T.; Sawabe, M.; Saeki, T.; Hayano, H.; Kato, S. [KEK, High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)

    2013-11-15

    We report the effect of different current densities on sulfur generation at Nb surface in the electropolishing (EP) with aged electrolyte. In this regard, we conducted a series of electropolishing (EP) experiments in aged EP electrolyte with high (≈50 mA/cm{sup 2}) and low (≈30 mA/cm{sup 2}) current densities on Nb surfaces. The experiments were carried out both for laboratory coupons and a real Nb single cell cavity with six witness samples located at three typical positions (equator, iris and beam pipe). Sample's surfaces were investigated by XPS (X-ray photoelectron spectroscopy), SEM (scanning electron microscope) and EDX (energy dispersive X-ray spectroscopy). The surface analysis showed that the EP with a high current density produced a huge amount of sulfate/sulfite particles at Nb surface whereas the EP with a low current density was very helpful to mitigate sulfate/sulfite at Nb surface in both the experiments.

  7. Generation of metal-binding staphylococci through surface display of combinatorially engineered cellulose-binding domains.

    Science.gov (United States)

    Wernérus, H; Lehtiö, J; Teeri, T; Nygren, P A; Ståhl, S

    2001-10-01

    Ni(2+)-binding staphylococci were generated through surface display of combinatorially engineered variants of a fungal cellulose-binding domain (CBD) from Trichoderma reesei cellulase Cel7A. Novel CBD variants were generated by combinatorial protein engineering through the randomization of 11 amino acid positions, and eight potentially Ni(2+)-binding CBDs were selected by phage display technology. These new variants were subsequently genetically introduced into chimeric surface proteins for surface display on Staphylococcus carnosus cells. The expressed chimeric proteins were shown to be properly targeted to the cell wall of S. carnosus cells, since full-length proteins could be extracted and affinity purified. Surface accessibility for the chimeric proteins was demonstrated, and furthermore, the engineered CBDs, now devoid of cellulose-binding capacity, were shown to be functional with regard to metal binding, since the recombinant staphylococci had gained Ni(2+)-binding capacity. Potential environmental applications for such tailor-made metal-binding bacteria as bioadsorbents in biofilters or biosensors are discussed.

  8. Synthesis of anisotropic swirling surface acoustic waves by inverse filter, towards integrated generators of acoustical vortices

    CERN Document Server

    Riaud, Antoine; Charron, Eric; Bussonnière, Adrien; Matar, Olivier Bou

    2015-01-01

    From radio-electronics signal analysis to biological samples actuation, surface acoustic waves (SAW) are involved in a multitude of modern devices. Despite this versatility, SAW transducers developed up to date only authorize the synthesis of the most simple standing or progressive waves such as plane and focused waves. In particular, acoustical integrated sources able to generate acoustical vortices (the analogue of optical vortices) are missing. In this work, we propose a flexible tool based on inverse filter technique and arrays of SAW transducers enabling the synthesis of prescribed complex wave patterns at the surface of anisotropic media. The potential of this setup is illustrated by the synthesis of a 2D analog of 3D acoustical vortices, namely "swirling surface acoustic waves". Similarly to their 3D counterpart, they appear as concentric structures of bright rings with a phase singularity in their center resulting in a central dark spot. Swirling SAW can be useful in fragile sensors whose neighborhood...

  9. Second Harmonic Generation Based on Strong Field Enhancement in Metallic Nanostructured Surface

    Directory of Open Access Journals (Sweden)

    Kitsakorn LOCHAROENRAT

    2014-12-01

    Full Text Available Although absorption is still the primary optical property of interest, other spectroscopic techniques including optical second harmonic generation (SHG are also used to understand anisotropic nature of nanomaterials. Benefit of SHG technique as compared with linear optical approach is that SH response is the most sensitive to surface potential changes and SH intensity mainly comes from surface/interface layers. This article reports that optical absorption spectra due to surface plasmon modes of metallic nanowires exhibit strong anisotropic absorption. Maxwell-Garnett simulation cannot fit with experimental results because of wire sizes much larger than wavelength of light, whereas finite-difference time-domain calculation can fit well with experimental findings in terms of position of photon energy of absorption peak with respect to polarization conditions. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6399

  10. Surface and sub-surface anatomy of the landscape: integrating Unmanned Aerial Vehicle Structure from Motion (UAV-SfM) and Ground Penetrating Radar (GRP) to investigate sedimentary features in the field. - an example from NW Australia

    Science.gov (United States)

    Callow, Nik; Leopold, Matthias; May, Simon Matthias

    2015-04-01

    Geomorphology is confronted by the challenge of reconstructing landscape features at appropriate scales, resolution and accuracy, that allows meaningful analysis of environmental processes and their implications. Field geomorphology offers a discrete snapshot (i.e. one or two field campaigns) to reconstruct how features have changed, evolved or responded over time. We explore the application of an emerging photogrammetry technique called Structure-from-Motion (SfM), which uses multiple photographs of the same feature (but taken at different locations) to create high-accuracy three-dimensional models of surface of sedimentary fans formed by extreme wave events. This approach is complimented by investigation of the sub-surface morphology using Ground Penetrating Radar (GPR). Using an UAV "octocopter", we captured 1208 photos with a DSLR camera (Canon EoS-M) at the height of 50m with a ground pixel resolution of 9mm, above a cyclone wash-over fan in the Exmouth Gulf (Western Australia) that measured about 500m inland by 300m wide. Based on 38 ground control point targets (with between 4 and 45 individual photographs per target) the SfM surface had an absolute total (XYZ) accuracy of 51mm (39mm X, 29mm Y and 14mm Y), based on RTK-DGPS surveying from a local ground reference station (with an absolute AUSPOS accuracy of 57mm X, 6mm Y, 50mm Z to AHD) and an overall relative point accuracy of 7mm. A sparse point cloud of over 5.5 million data points was generated using only points with a reconstruction accuracy of RGB colour of each XYZ pixel) using K-Means clustering within Python. The output was then manually classified into ground and non-ground points, and the geostatistical analyst functionality of ArcGIS used to produce a final bare-earth DEM. This approach has allowed the study team to economically collect an unprecedented high-resolution and accuracy topographic model of this feature to compliment on-ground sediment, geophysics and dating work to analyse the

  11. Polarisation-dependent generation of fs-laser induced periodic surface structures

    Energy Technology Data Exchange (ETDEWEB)

    Gräf, Stephan, E-mail: stephan.graef@uni-jena.de; Müller, Frank A.

    2015-03-15

    Highlights: • LIPSS formation was studied under static and dynamic alteration of laser polarisation. • The dynamic polarisation is based on a continuously rotating E-field vector. • LIPSS generated with static linear polarisation reveal a period of 925 nm. • LIPSS orientation follows the direction of the rotating E-field vector. • The approach facilitates the formation of disordered structures for optical applications. - Abstract: The formation of laser induced periodic surface structures (LIPPS) was investigated on polished stainless steel surfaces under irradiation with fs-laser pulses characterised by a pulse duration τ = 300 fs, a laser wavelength λ = 1025 nm, a repetition frequency f{sub rep} = 250 Hz and a laser fluence F = 1 J/cm{sup 2}. For this purpose line scans with a scanning velocity v = 0.5 mm/s were performed in air environment at normal incidence utilising a well-defined temporal control of the electrical field vector. The generated surface structures were characterised by optical microscopy, by scanning electron microscopy and by atomic force microscopy in combination with Fourier transformation. The results reveal the formation of a homogenous and highly periodic surface pattern of ripples with a period Λ{sub exp} ≈ 925 nm aligned perpendicular to the incident electric field vector for static linear polarisation states. Utilising a motor-driven rotation device it was demonstrated that a continuously rotating electric field vector allows to transfer the originally well-ordered periodic ripples into tailored disordered surface structures that could be of particular interest for e.g. absorbing surfaces, plasmonic enhanced optoelectronic devices and biomedical applications.

  12. Comparison of hospital room surface disinfection using a novel ultraviolet germicidal irradiation (UVGI) generator.

    Science.gov (United States)

    Jelden, Katelyn C; Gibbs, Shawn G; Smith, Philip W; Hewlett, Angela L; Iwen, Peter C; Schmid, Kendra K; Lowe, John J

    2016-09-01

    The estimated 721,800 hospital acquired infections per year in the United States have necessitated development of novel environmental decontamination technologies such as ultraviolet germicidal irradiation (UVGI). This study evaluated the efficacy of a novel, portable UVGI generator (the TORCH, ChlorDiSys Solutions, Inc., Lebanon, NJ) to disinfect surface coupons composed of plastic from a bedrail, stainless steel, chrome-plated light switch cover, and a porcelain tile that were inoculated with methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus faecalis (VRE). Each surface type was placed at 6 different sites within a hospital room and treated by 10-min ultraviolet-C (UVC) exposures using the TORCH with doses ranging from 0-688 mJ/cm(2) between sites. Organism reductions were compared with untreated surface coupons as controls. Overall, UVGI significantly reduced MRSA by an average of 4.6 log10 (GSD: 1.7 log10, 77% inactivation, p < 0.0001) and VRE by an average of 3.9 log10 (GSD: 1.7 log10, 65% inactivation, p < 0.0001). MRSA on bedrail was reduced significantly (p < 0.0001) less than on other surfaces, while VRE was reduced significantly less on chrome (p = 0.0004) and stainless steel (p = 0.0012) than porcelain tile. Organisms out of direct line of sight of the UVC generator were reduced significantly less (p < 0.0001) than those directly in line of sight. UVGI was found an effective method to inactivate nosocomial pathogens on surfaces evaluated within the hospital environment in direct line of sight of UVGI treatment with variation between organism and surface types.

  13. Integrated system for investigating sub-surface features of a rock formation

    Energy Technology Data Exchange (ETDEWEB)

    Vu, Cung Khac; Skelt, Christopher; Nihei, Kurt; Johnson, Paul A.; Guyer, Robert; Ten Cate, James A.; Le Bas, Pierre -Yves; Larmat, Carene S.

    2015-08-18

    A system for investigating non-linear properties of a rock formation around a borehole is provided. The system includes a first sub-system configured to perform data acquisition, control and recording of data; a second subsystem in communication with the first sub-system and configured to perform non-linearity and velocity preliminary imaging; a third subsystem in communication with the first subsystem and configured to emit controlled acoustic broadcasts and receive acoustic energy; a fourth subsystem in communication with the first subsystem and the third subsystem and configured to generate a source signal directed towards the rock formation; and a fifth subsystem in communication with the third subsystem and the fourth subsystem and configured to perform detection of signals representative of the non-linear properties of the rock formation.

  14. Integrated system for investigating sub-surface features of a rock formation

    Science.gov (United States)

    Vu, Cung Khac; Skelt, Christopher; Nihei, Kurt; Johnson, Paul A.; Guyer, Robert; Ten Cate, James A.; Le Bas, Pierre -Yves; Larmat, Carene S.

    2015-08-18

    A system for investigating non-linear properties of a rock formation around a borehole is provided. The system includes a first sub-system configured to perform data acquisition, control and recording of data; a second subsystem in communication with the first sub-system and configured to perform non-linearity and velocity preliminary imaging; a third subsystem in communication with the first subsystem and configured to emit controlled acoustic broadcasts and receive acoustic energy; a fourth subsystem in communication with the first subsystem and the third subsystem and configured to generate a source signal directed towards the rock formation; and a fifth subsystem in communication with the third subsystem and the fourth subsystem and configured to perform detection of signals representative of the non-linear properties of the rock formation.

  15. Comparative study of resonant and sequential features in electron field emission from composite surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Filip, Valeriu, E-mail: vfilip@gmail.com [Faculty of Physics, University of Bucharest, 405 Atomistilor Str., Magurele 077125, P.O. Box MG-11 (Romania); Institute of Microelectronics and Photonics, Zhejiang University, 38 Zheda Road, Hangzhou 310027 (China); Wong, Hei, E-mail: xiwang@zju.edu.cn [Institute of Microelectronics and Photonics, Zhejiang University, 38 Zheda Road, Hangzhou 310027 (China)

    2016-06-01

    A simple model of a layered hetero-structure was developed and used to simultaneously compute and compare resonant and sequential electron field emission currents. It was found that, while various slope changes appear in both current-field characteristics, for the sequential tunneling type of emission, such features are merely interference effects. They occur in parts of the structure, prior to the electrons' lingering in the quasi-bound states from which field emission proceeds. These purely quantum effects further combine with the flow effects resulting from the steady current requirement and give corresponding field variations of the electron population of the quasi-bound states, which further react on the resonant part of the current. A spectral approach of the two types of field emission is also considered by computing the total energy distribution of electrons in each case. The differences between these possible spectra are pointed out and discussed. - Highlights: • The relationship between resonant and sequential field emission is studied. • Sequential current–voltage characteristics show barrier-controlled undulations. • Resonant characteristics depend mainly on the width/shape of the topmost well. • The resonant and sequential total energy distributions differ widely.

  16. Quality classification of wooden surfaces using Gabor filters and genetic feature optimization

    Science.gov (United States)

    Poelzleitner, Wolfgang; Schwingskakl, Gert

    1999-08-01

    We apply a model of texture segmentation using multiple spatially and spectrally localized filters, known as Gabor filters, to the analysis of texture and effect regions found on wooden boards. Specifically we present a method to find an optimal set of parameters for a given 2D object detection method. The method uses banks of Gabor filters to limit the rang of spatial frequencies, where mutually distinct textures differ significantly in their dominant characterizing frequencies. By encoding images into multiple narrow spatial frequency and orientation channels a local classification of texture regions can be achieved. Unlike other methods applying Gabor filters, we do not use a full Gabor transform, but use feature selection techniques to maximize discrimination. The selection method uses a genetic algorithm to optimize various parameters of the system including Gabor weights, and the parameters of morphological pre-processing. We demonstrate the applicability of the method to the task of classifying wooden textures, and report experimental results using the proposed method.

  17. Absorption features caused by oscillations of electrons on the surface of a quark star

    CERN Document Server

    Xu, R X; Weber, F; Yu, J W; Molodtsova, I V

    2011-01-01

    If quark stars exist, they may be enveloped in thin electron layers (electron seas), which uniformly surround the entire star. These layers will be affected by the magnetic fields of quark stars in such a way that the electron seas would transmit hydromagnetic cyclotron waves, as studied in this paper. Particular attention is devoted to vortex hydrodynamical oscillations of the electron sea. The frequency spectrum of these oscillations is derived in analytic form. If the thermal X-ray spectra of quark stars are modulated by vortex hydrodynamical vibrations, the thermal spectra of compact stars, foremost cental compact objects (CCOs) and X-ray dim isolated neutron stars (XDINSs), could be used to verify the existence of these vibrational modes observationally. The central compact object 1E 1207.4-5209 appears particularly interesting in this context, since its absorption features at 0.7 keV and 1.4 keV can be comfortably explained in the framework of the hydro-cyclotron oscillation model.

  18. The surface velocity feature of Glacier No.1 at the headwater of Urumqi River,Tianshan Mountain

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The movement of a glacier can redistribute glacier mass balance and change water and thermal conditions of the glacier.Thus,the glacier can maintain its dynamic balance.Surface velocity of a glacier is a basic feature of glacier movement.With successive monthly observations from 2006 to 2008,we obtained spatial and temporal variations for surface velocity of Glacier No.1 at the headwater of Urumqi River,Tianshan Mountain.Dynamic simulation was used to verify the findings.Results show that altitudinal distribution of glacier velocity was influenced by synthetic effects such as glacier thickness,slope,and bedrock morphology.However,seasonal variation was influenced by changing glacier thickness.

  19. Surface features and catalytic performance of platinum/alumina catalysts in slurry-phase hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez-Ortiz, M.A.; Gonzalez-Marcos, M.P.; Arnaiz-Aguilar, S.; Gonzalez-Marcos, J.A.; Gonzalez-Velasco, J.R. (Univ. del Pais Vasco/Euskal Hirrika Unibertsitatea, Bilbao (Spain). Dept. de Ingenierlla Quimica)

    1993-11-01

    Several platinum catalysts supported on three commercial [gamma]-aluminas were prepared by impregnation and anionic exchange using aqueous solutions of H[sub 2]PtCl[sub 6]. A number of methods were used to characterize the precursors as well as the final catalysts, including TGA, TPR, and hydrogen chemisorption at 298 K. TPR measurements showed two reduction peaks for the catalysts: the first one corresponding to reduction of the metal precursor to platinum and the second one associated to formation of a surface complex, Pt-Al[sub 2]O[sub 3[minus]x], With partial reduction of the support. The activity of the different catalysts was tested in the slurry-phase hydrogenation of benzene. The results obtained in the activity measurements have been correlated to the characteristics of the catalysts.

  20. Generation of amphoteric surfaces via glow-discharge technique with single precursor and the behavior of bovine serum albumin at the surface.

    Science.gov (United States)

    Akdoğan, Ebru; Mutlu, Mehmet

    2012-01-01

    Amphoteric surfaces were generated on silicone substrates via plasma polymerization technique using a single monomer; diethyl allyl phosphate (DAP). Surface characterization was performed by the means of contact angle titration and Fourier transform infrared (FTIR) spectroscopy. The surface of silicone was found to be slightly basic with an apparent basicity of 0.12 μmol/m(2) while plasma surface modification made the surfaces amphoteric with the surface acid/base concentration adjustable by varying plasma parameters. The adsorption of model protein; bovine serum albumin (BSA) on the surfaces was found to be correlated to the surface acid/base ratio. Percent reduction on modified surfaces compared to bare silicone surface was 32, 59 and 92% for 20 W 5 min, 60 W 5 min and 100 W 5 min modified surfaces respectively. Conformational change of BSA upon adsorption to the surfaces was investigated with FTIR-ATR spectroscopy. It has been shown that BSA preserves more of its secondary structure upon adsorption to plasma modified surfaces than the bare silicone surface. It has been concluded that DAP modified surfaces reduces the amount of protein adsorption on the surfaces due to the modified surfaces amphoteric nature and the ability of modified surfaces to preserve the secondary structure of adsorbed protein better than the bare silicone surface.

  1. The role of spatial confinement for improvement of laser-induced Mg plasma parameters and growth of surface features

    Science.gov (United States)

    Hayat, Asma; Bashir, Shazia; Rafique, Muhammad Shahid; Ahmad, Riaz; Akram, Mahreen; Mahmood, Khaliq; Zaheer, Ali

    2017-08-01

    The role of spatial confinement for improvement of laser-induced Mg plasma parameters and growth of surface features is investigated by introducing a metallic blocker. Nd: YAG laser at various fluences ranging from 7 to 28 J cm-2 was employed as an irradiation source. All measurements were performed in the presence of Ar under different pressures. Confinement effects offered by metallic blocker are investigated by placing the blocker at different distances of 6, 8 and 10 mm from the target surface. It is revealed from laser-induced breakdown spectroscopy analysis that both plasma parameters, i.e., excitation temperature and electron number density initially increase with increasing laser fluence due to enhancement in energy deposition. With further increase in laser fluence, a decreasing trend followed by saturation is observed which is attributable to shielding effect and self-regulating regime. It is also observed that spatial confinement offered by metallic blocker is responsible for the significant enhancement of both electron temperature and electron number density of Mg plasma. This is true for all laser fluences and pressures of Ar. Maximum values of electron temperature and electron number density without blocker are 8335 K and 2.4 × 1016 cm-3, respectively, whereas these values are enhanced to 12,200 K and 4 × 1016 cm-3 in the presence of the blocker. The physical mechanisms responsible for the enhancement of Mg plasma parameters are plasma compression, confinement and pronounced collisional excitations due to reflection of shock waves. Scanning electron microscope analysis was performed to explore the surface morphology of laser-ablated Mg. It reveals the formation of cones, cavities and ripples. These features become more distinct and well defined in the presence of the blocker due to plasma confinement. The optimum combination of blocker distance, fluence and Ar pressure can identify the suitable conditions for defining the role of plasma parameters

  2. Sensitivity of Venus surface emissivity retrieval to model variations of CO2 opacity, cloud features, and deep atmosphere temperature field

    Science.gov (United States)

    Kappel, David; Arnold, Gabriele; Haus, Rainer

    2012-07-01

    The Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) aboard ESA's Venus Express space probe has acquired a wealth of nightside emission spectra from Venus and provides the first global database for systematic atmospheric and surface studies in the IR. The infrared mapping channel (VIRTIS-M-IR) sounds the atmosphere and surface at high spatial and temporal resolution and coverage. Quantitative analyses of data call for a sophisticated radiative transfer simulation model of Venus' atmosphere to be used in atmospheric and surface parameter retrieval procedures that fit simulated spectra to the measured data. The surface emissivity can be retrieved from VIRTIS-M-IR measurements in the transparency windows around 1 μm, but it is not easy to derive, since atmospheric influences strongly interfere with surface information. There are mainly three atmospheric model parameters that may affect quantitative results of surface emissivity retrievals: CO_2 opacity, cloud features, and deep atmosphere temperature field. The CO_2 opacity with respect to allowed transitions is usually computed by utilizing a suitable line data base and certain line shape models that consider collisional line mixing. Both line data bases and shape models are not well established from measurements under the environmental conditions in the deep atmosphere of Venus. Pressure-induced additional continuum absorption introduces further opacity uncertainties. The clouds of Venus are usually modeled by a four-modal distribution of spherical droplets of about 75% sulfuric acid, where each mode is characterized by a different mean and standard deviation of droplet size distribution and a different initial altitude abundance profile. The influence of possible cloud mode variations on surface emissivity retrieval results is investigated in the paper. Future retrieval procedures will aim at a separation of cloud mode and surface emissivity variations using different atmospheric windows sounded by

  3. a Detailed Study about Digital Surface Model Generation Using High Resolution Satellite Stereo Imagery

    Science.gov (United States)

    Gong, K.; Fritsch, D.

    2016-06-01

    Photogrammetry is currently in a process of renaissance, caused by the development of dense stereo matching algorithms to provide very dense Digital Surface Models (DSMs). Moreover, satellite sensors have improved to provide sub-meter or even better Ground Sampling Distances (GSD) in recent years. Therefore, the generation of DSM from spaceborne stereo imagery becomes a vivid research area. This paper presents a comprehensive study about the DSM generation of high resolution satellite data and proposes several methods to implement the approach. The bias-compensated Rational Polynomial Coefficients (RPCs) Bundle Block Adjustment is applied to image orientation and the rectification of stereo scenes is realized based on the Project-Trajectory-Based Epipolarity (PTE) Model. Very dense DSMs are generated from WorldView-2 satellite stereo imagery using the dense image matching module of the C/C++ library LibTsgm. We carry out various tests to evaluate the quality of generated DSMs regarding robustness and precision. The results have verified that the presented pipeline of DSM generation from high resolution satellite imagery is applicable, reliable and very promising.

  4. Computer vision-based apple grading for golden delicious apples based on surface features

    Directory of Open Access Journals (Sweden)

    Payman Moallem

    2017-03-01

    Full Text Available In this paper, a computer vision-based algorithm for golden delicious apple grading is proposed which works in six steps. Non-apple pixels as background are firstly removed from input images. Then, stem end is detected by combination of morphological methods and Mahalanobis distant classifier. Calyx region is also detected by applying K-means clustering on the Cb component in YCbCr color space. After that, defects segmentation is achieved using Multi-Layer Perceptron (MLP neural network. In the next step, stem end and calyx regions are removed from defected regions to refine and improve apple grading process. Then, statistical, textural and geometric features from refined defected regions are extracted. Finally, for apple grading, a comparison between performance of Support Vector Machine (SVM, MLP and K-Nearest Neighbor (KNN classifiers is done. Classification is done in two manners which in the first one, an input apple is classified into two categories of healthy and defected. In the second manner, the input apple is classified into three categories of first rank, second rank and rejected ones. In both grading steps, SVM classifier works as the best one with recognition rate of 92.5% and 89.2% for two categories (healthy and defected and three quality categories (first rank, second rank and rejected ones, among 120 different golden delicious apple images, respectively, considering K-folding with K = 5. Moreover, the accuracy of the proposed segmentation algorithms including stem end detection and calyx detection are evaluated for two different apple image databases.

  5. Modification of the large-scale features of high Reynolds number wall turbulence by passive surface obtrusions

    Energy Technology Data Exchange (ETDEWEB)

    Monty, J.P.; Lien, K.; Chong, M.S. [University of Melbourne, Department of Mechanical Engineering, Parkville, VIC (Australia); Allen, J.J. [New Mexico State University, Department of Mechanical Engineering, Las Cruces, NM (United States)

    2011-12-15

    A high Reynolds number boundary-layer wind-tunnel facility at New Mexico State University was fitted with a regularly distributed braille surface. The surface was such that braille dots were closely packed in the streamwise direction and sparsely spaced in the spanwise direction. This novel surface had an unexpected influence on the flow: the energy of the very large-scale features of wall turbulence (approximately six-times the boundary-layer thickness in length) became significantly attenuated, even into the logarithmic region. To the author's knowledge, this is the first experimental study to report a modification of 'superstructures' in a rough-wall turbulent boundary layer. The result gives rise to the possibility that flow control through very small, passive surface roughness may be possible at high Reynolds numbers, without the prohibitive drag penalty anticipated heretofore. Evidence was also found for the uninhibited existence of the near-wall cycle, well known to smooth-wall-turbulence researchers, in the spanwise space between roughness elements. (orig.)

  6. PES Surface Modification Using Green Chemistry: New Generation of Antifouling Membranes.

    Science.gov (United States)

    Nady, Norhan

    2016-04-18

    A major limitation in using membrane-based separation processes is the loss of performance due to membrane fouling. This drawback can be addressed thanks to surface modification treatments. A new and promising surface modification using green chemistry has been recently investigated. This modification is carried out at room temperature and in aqueous medium using green catalyst (enzyme) and nontoxic modifier, which can be safely labelled "green surface modification". This modification can be considered as a nucleus of new generation of antifouling membranes and surfaces. In the current research, ferulic acid modifier and laccase bio-catalyst were used to make poly(ethersulfone) (PES) membrane less vulnerable to protein adsorption. The blank and modified PES membranes are evaluated based on e.g., their flux and protein repellence. Both the blank and the modified PES membranes (or laminated PES on silicon dioxide surface) are characterized using many techniques e.g., SEM, EDX, XPS and SPM, etc. The pure water flux of the most modified membranes was reduced by 10% on average relative to the blank membrane, and around a 94% reduction in protein adsorption was determined. In the conclusions section, a comparison between three modifiers-ferulic acid, and two other previously used modifiers (4-hydroxybenzoic acid and gallic acid)-is presented.

  7. Sum frequency generation spectroscopy study of hydrogenated stepped Si(111) surfaces made by molecular hydrogen exposure

    Science.gov (United States)

    Hien, K. T. T.; Sattar, M. A.; Miyauchi, Y.; Mizutani, G.; Rutt, H. N.

    2017-09-01

    Hydrogen adsorption on stepped Si(111) surfaces 9.5° miscut in the [ 1 ̅ 1 ̅ 2 ] direction has been investigated in situ in a UHV chamber with a base pressure of 10-8 Pa. The H-Si(111)1×1 surface was prepared by exposing the wafer to ultra-pure hydrogen gas at a pressure of 470 Pa. Termination of hydrogen on terraces and steps was observed by sum frequency generation (SFG) with several polarization combinations such as ppp, ssp, pps, spp, psp, sps, pss and sss. Here the 1st, 2nd and 3rd symbols indicate SFG, visible and IR polarizations, respectively. ppp and ssp-SFG clearly showed only two modes: the Si-H stretching vibration terrace mode at 2082 cm-1 (A) and the vertical step dihydride vibration mode at 2094 cm-1 (C1). Interesting points are the appearance of the C1 mode in contrast to the previous SFG spectrum of the H-Si(111)1×1 surface with the same miscut surface angle prepared by wet chemical etching. We suggest that the formation of step dihydride and its orientation on the Si(111) stepped surfaces depend strongly on the preparation method.

  8. PES Surface Modification Using Green Chemistry: New Generation of Antifouling Membranes

    Directory of Open Access Journals (Sweden)

    Norhan Nady

    2016-04-01

    Full Text Available A major limitation in using membrane-based separation processes is the loss of performance due to membrane fouling. This drawback can be addressed thanks to surface modification treatments. A new and promising surface modification using green chemistry has been recently investigated. This modification is carried out at room temperature and in aqueous medium using green catalyst (enzyme and nontoxic modifier, which can be safely labelled “green surface modification”. This modification can be considered as a nucleus of new generation of antifouling membranes and surfaces. In the current research, ferulic acid modifier and laccase bio-catalyst were used to make poly(ethersulfone (PES membrane less vulnerable to protein adsorption. The blank and modified PES membranes are evaluated based on e.g., their flux and protein repellence. Both the blank and the modified PES membranes (or laminated PES on silicon dioxide surface are characterized using many techniques e.g., SEM, EDX, XPS and SPM, etc. The pure water flux of the most modified membranes was reduced by 10% on average relative to the blank membrane, and around a 94% reduction in protein adsorption was determined. In the conclusions section, a comparison between three modifiers—ferulic acid, and two other previously used modifiers (4-hydroxybenzoic acid and gallic acid—is presented.

  9. Revisiting the quantitative features of surface-assisted laser desorption/ionization mass spectrometric analysis.

    Science.gov (United States)

    Wu, Ching-Yi; Lee, Kai-Chieh; Kuo, Yen-Ling; Chen, Yu-Chie

    2016-10-28

    Surface-assisted laser desorption/ionization (SALDI) coupled with mass spectrometry (MS) is frequently used to analyse small organics owing to its clean background. Inorganic materials can be used as energy absorbers and the transfer medium to facilitate the desorption/ionization of analytes; thus, they are used as SALDI-assisting materials. Many studies have demonstrated the usefulness of SALDI-MS in quantitative analysis of small organics. However, some characteristics occurring in SALDI-MS require certain attention to ensure the reliability of the quantitative analysis results. The appearance of a coffee-ring effect in SALDI sample preparation is the primary factor that can affect quantitative SALDI-MS analysis results. However, to the best of our knowledge, there are no reports relating to quantitative SALDI-MS analysis that discuss or consider this effect. In this study, the coffee-ring effect is discussed using nanoparticles and nanostructured substrates as SALDI-assisting materials to show how this effect influences SALDI-MS analysis results. Potential solutions for overcoming the existing problems are also suggested.This article is part of the themed issue 'Quantitative mass spectrometry'.

  10. The Word Composite Effect Depends on Abstract Lexical Representations But Not Surface Features Like Case and Font

    Science.gov (United States)

    Ventura, Paulo; Fernandes, Tânia; Leite, Isabel; Almeida, Vítor B.; Casqueiro, Inês; Wong, Alan C.-N.

    2017-01-01

    Prior studies have shown that words show a composite effect: When readers perform a same-different matching task on a target-part of a word, performance is affected by the irrelevant part, whose influence is severely reduced when the two parts are misaligned. However, the locus of this word composite effect is largely unknown. To enlighten it, in two experiments, Portuguese readers performed the composite task on letter strings: in Experiment 1, in written words varying in surface features (between-participants: courier, notera, alternating-cAsE), and in Experiment 2 in pseudowords. The word composite effect, signaled by a significant interaction between alignment of the two word parts and congruence between parts was found in the three conditions of Experiment 1, being unaffected by NoVeLtY of the configuration or by handwritten form. This effect seems to have a lexical locus, given that in Experiment 2 only the main effect of congruence between parts was significant and was not modulated by alignment. Indeed, the cross-experiment analysis showed that words presented stronger congruence effects than pseudowords only in the aligned condition, because when misaligned the whole lexical item configuration was disrupted. Therefore, the word composite effect strongly depends on abstract lexical representations, as it is unaffected by surface features and is specific to lexical items. PMID:28676783

  11. Effect of the measurement size on the robustness of the assessment of the features specific for cylinder liner surfaces

    Science.gov (United States)

    Dimkovski, Z.; Ohlsson, R.; Rosén, B.-G.

    2014-01-01

    The quality of the cylinder liner surface is of great importance due to its impact on the fuel/oil consumption and emissions of the internal combustion engine. A good liner function depends on the size and distribution of the deep honing grooves and the amount of the cold work material (Blechmantel) left inside the grooves after finishing. A fast evaluation of these features requires optical three-dimensional measurements with a large area and good resolution, but many interferometers used today have limited resolution when measuring larger areas. To find out how the measurement size and resolution would affect the quantification and the variation of the parameters, two objectives, 2.5 × and 10 × , were used for measuring a cylinder liner from a truck engine. The Blechmantel was of special interest as it first comes into contact with piston/rings, detaches as particles and wears the running surfaces. The 2.5 × objective showed more robust assessment than the 10 × one, manifested by a lower coefficient of variation for the parameters describing the features: Blechmantel, groove width and height, groove balance and number of grooves. This means that fewer measurements are required if a 2.5 × objective is used in production and hence the time and cost of the liner would be decreased.

  12. Examining the Impact of Question Surface Features on Students’ Answers to Constructed-Response Questions on Photosynthesis

    Science.gov (United States)

    Weston, Michele; Haudek, Kevin C.; Prevost, Luanna; Urban-Lurain, Mark; Merrill, John

    2015-01-01

    One challenge in science education assessment is that students often focus on surface features of questions rather than the underlying scientific principles. We investigated how student written responses to constructed-response questions about photosynthesis vary based on two surface features of the question: the species of plant and the order of two question prompts. We asked four versions of the question with different combinations of the two plant species and order of prompts in an introductory cell biology course. We found that there was not a significant difference in the content of student responses to versions of the question stem with different species or order of prompts, using both computerized lexical analysis and expert scoring. We conducted 20 face-to-face interviews with students to further probe the effects of question wording on student responses. During the interviews, we found that students thought that the plant species was neither relevant nor confusing when answering the question. Students identified the prompts as both relevant and confusing. However, this confusion was not specific to a single version. PMID:25999312

  13. Catalyzed hydrogenation of nitrogen and ethylene on metal (Fe, Pt) single crystal surfaces and effects of coadsorption: A sum frequency generation vibrational spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Westerberg, Staffan Per Gustav [Univ. of California, Berkeley, CA (United States)

    2004-01-01

    High-pressure catalytic reactions and associated processes, such as adsorption have been studied on a molecular level on single crystal surfaces. Sum Frequency Generation (SFG) vibrational spectroscopy together with Auger Electron Spectroscopy (AES), Temperature Programmed Desorption (TPD) and Gas Chromatography (GC) were used to investigate the nature of species on catalytic surfaces and to measure the catalytic reaction rates. Special attention has been directed at studying high-pressure reactions and in particular, ammonia synthesis in order to identify reaction intermediates and the influence of adsorbates on the surface during reaction conditions. The adsorption of gases N2, H2, O2 and NH3 that play a role in ammonia synthesis have been studied on the Fe(111) crystal surface by sum frequency generation vibrational spectroscopy using an integrated Ultra-High Vacuum (UHV)/high-pressure system. SFG spectra are presented for the dissociation intermediates, NH2 (~3325 cm-1) and NH (~3235 cm-1) under high pressure of ammonia (200 Torr) on the clean Fe(111) surface. Addition of 0.5 Torr of oxygen to 200 Torr of ammonia does not significantly change the bonding of dissociation intermediates to the surface. However, it leads to a phase change of nearly 180° between the resonant and non-resonant second order non-linear susceptibility of the surface, demonstrated by the reversal of the SFG spectral features. Heating the surface in the presence of 200 Torr ammonia and 0.5 Torr oxygen reduces the oxygen coverage, which can be seen from the SFG spectra as another relative phase change of 180°. The reduction of the oxide is also supported by Auger electron spectroscopy. The result suggests that the phase change of the spectral features could serve as a sensitive indicator of the chemical environment of the adsorbates.

  14. Catalyzed hydrogenation of nitrogen and ethylene on metal (Fe, Pt) single crystal surfaces and effects of coadsorption: A sum frequency generation vibrational spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Westerberg, Staffan Per Gustav

    2004-12-15

    High-pressure catalytic reactions and associated processes, such as adsorption have been studied on a molecular level on single crystal surfaces. Sum Frequency Generation (SFG) vibrational spectroscopy together with Auger Electron Spectroscopy (AES), Temperature Programmed Desorption (TPD) and Gas Chromatography (GC) were used to investigate the nature of species on catalytic surfaces and to measure the catalytic reaction rates. Special attention has been directed at studying high-pressure reactions and in particular, ammonia synthesis in order to identify reaction intermediates and the influence of adsorbates on the surface during reaction conditions. The adsorption of gases N{sub 2}, H{sub 2}, O{sub 2} and NH{sub 3} that play a role in ammonia synthesis have been studied on the Fe(111) crystal surface by sum frequency generation vibrational spectroscopy using an integrated Ultra-High Vacuum (UHV)/high-pressure system. SFG spectra are presented for the dissociation intermediates, NH{sub 2} ({approx}3325 cm{sup -1}) and NH ({approx}3235 cm{sup -1}) under high pressure of ammonia (200 Torr) on the clean Fe(111) surface. Addition of 0.5 Torr of oxygen to 200 Torr of ammonia does not significantly change the bonding of dissociation intermediates to the surface. However, it leads to a phase change of nearly 180{sup o} between the resonant and non-resonant second order non-linear susceptibility of the surface, demonstrated by the reversal of the SFG spectral features. Heating the surface in the presence of 200 Torr ammonia and 0.5 Torr oxygen reduces the oxygen coverage, which can be seen from the SFG spectra as another relative phase change of 180{sup o}. The reduction of the oxide is also supported by Auger electron spectroscopy. The result suggests that the phase change of the spectral features could serve as a sensitive indicator of the chemical environment of the adsorbates.

  15. Study on the Generation Characteristics of Dielectric Barrier Discharge Plasmas on Water Surface

    Science.gov (United States)

    Liu, Wenzheng; Li, Chuanhui

    2014-01-01

    A new contact glow discharge electrode on the surface of water was designed and employed in this study. Because of the strong field strength in the small air gap formed by the electrode and the water surface, glow discharge plasmas were generated and used to treat waste water. The electric field distribution of the designed electrode model was simulated by MAXWELL 3D® simulation software, and the discharge parameters were measured. Through a series of experiments, we investigated the impact of optimal designs, such as the dielectric of the electrode, immersion depths, and curvature radii of the electrode on the generation characteristics of plasmas. In addition, we designed an equipotential multi-electrode configuration to treat a Methyl Violet solution and observe the discoloration effect. The experimental and simulation results indicate that the designed electrodes can realize glow discharge with a relative low voltage, and the generated plasmas covered a large area and were in stable state. The efficiency of water treatment is improved and optimized with the designed electrodes.

  16. Balanced gait generations of a two-legged robot on sloping surface

    Indian Academy of Sciences (India)

    Pandu Ranga Vundavilli; Dilip Kumar Pratihar

    2011-08-01

    In this paper, dynamically balanced gait generation problem of a 7-DOF two-legged robot moving up and down through the sloping surface is presented. The gait of the lower links during locomotion is obtained after assuming suitable trajectories for the swing leg and hip joint. The trunk motion is initially generated based on the concept of static balance, which is different from the well-known semi-inverse method and then checked for its dynamic balance calculated using the concept of Zero-Moment Point (ZMP). Lagrange–Euler formulation is attempted for the determination of joint torques. Average power consumption at each joint is then determined based on the computed torques. Moreover, the variations of dynamic balance margin and average power consumption are studied for both ascending and descending through the sloping surface. Both of them are found to be more for the ascending gait generation compared to those for the descending case. The effects of variations of the slope have also been studied on the average dynamic balance margin and power consumption for both the cases.

  17. Speckle noise reduction for computer generated holograms of objects with diffuse surfaces

    Science.gov (United States)

    Symeonidou, Athanasia; Blinder, David; Ahar, Ayyoub; Schretter, Colas; Munteanu, Adrian; Schelkens, Peter

    2016-04-01

    Digital holography is mainly used today for metrology and microscopic imaging and is emerging as an important potential technology for future holographic television. To generate the holographic content, computer-generated holography (CGH) techniques convert geometric descriptions of a 3D scene content. To model different surface types, an accurate model of light propagation has to be considered, including for example, specular and diffuse reflection. In previous work, we proposed a fast CGH method for point cloud data using multiple wavefront recording planes, look-up tables (LUTs) and occlusion processing. This work extends our method to account for diffuse reflections, enabling rendering of deep 3D scenes in high resolution with wide viewing angle support. This is achieved by modifying the spectral response of the light propagation kernels contained by the look-up tables. However, holograms encoding diffuse reflective surfaces depict significant amounts of speckle noise, a problem inherent to holography. Hence, techniques to improve the reduce speckle noise are evaluated in this paper. Moreover, we propose as well a technique to suppress the aperture diffraction during numerical, viewdependent rendering by apodizing the hologram. Results are compared visually and in terms of their respective computational efficiency. The experiments show that by modelling diffuse reflection in the LUTs, a more realistic yet computationally efficient framework for generating high-resolution CGH is achieved.

  18. Real-Time Visualization of Tissue Surface Biochemical Features Derived From Fluorescence Lifetime Measurements.

    Science.gov (United States)

    Gorpas, Dimitris; Ma, Dinglong; Bec, Julien; Yankelevich, Diego R; Marcu, Laura

    2016-08-01

    Fiber based fluorescence lifetime imaging has shown great potential for intraoperative diagnosis and guidance of surgical procedures. Here we describe a novel method addressing a significant challenge for the practical implementation of this technique, i.e., the real-time display of the quantified biochemical or functional tissue properties superimposed on the interrogated area. Specifically, an aiming beam (450 nm) generated by a continuous-wave laser beam was merged with the pulsed fluorescence excitation light in a single delivery/collection fiber and then imaged and segmented using a color-based algorithm. We demonstrate that this approach enables continuous delineation of the interrogated location and dynamic augmentation of the acquired frames with the corresponding fluorescence decay parameters. The method was evaluated on a fluorescence phantom and fresh tissue samples. Current results demonstrate that 34 frames per second can be achieved for augmenting videos of 640 × 512 pixels resolution. Also we show that the spatial resolution of the fluorescence lifetime map depends on the tissue optical properties, the scanning speed, and the frame rate. The dice similarity coefficient between the fluorescence phantom and the reconstructed maps was estimated to be as high as 93%. The reported method could become a valuable tool for augmenting the surgeon's field of view with diagnostic information derived from the analysis of fluorescence lifetime data in real-time using handheld, automated, or endoscopic scanning systems. Current method provides also a means for maintaining the tissue light exposure within safety limits. This study provides a framework for using an aiming beam with other point spectroscopy applications.

  19. WE-AB-204-04: Feature Selection and Clustering Optimization for Pseudo-CT Generation in MR-Based Attenuation Correction and Radiation Therapy Planning

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, J; Su, K [Case Center for Imaging Research, Case Western Reserve University, Cleveland, Ohio (United States); Department of Radiology, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, Ohio (United States); Hu, L; Traughber, M [Philips Healthcare, Cleveland, Ohio (United States); Pereira, G; Traughber, B [Department of Radiation Oncology, University Hospitals Seidman Cancer Center, Case Western Reserve University, Cleveland, Ohio (United States); Herrmann, K [Department of Radiology, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, Ohio (United States); Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, Ohio (United States); Muzic, R [Case Center for Imaging Research, Case Western Reserve University, Cleveland, Ohio (United States); Department of Radiology, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, Ohio (United States); Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH (United States)

    2015-06-15

    Purpose: Accurate and robust photon attenuation derived from MR is essential for PET/MR and MR-based radiation treatment planning applications. Although the fuzzy C-means (FCM) algorithm has been applied for pseudo-CT generation, the input feature combination and the number of clusters have not been optimized. This study aims to optimize both for clinically practical pseudo-CT generation. Methods: Nine volunteers were recruited. A 190-second, single-acquisition UTE-mDixon with 25% (angular) sampling and 3D radial readout was performed to acquire three primitive MR features at TEs of 0.1, 1.5, and 2.8 ms: the free-induction-decay (FID), the first and the second echo images. Three derived images, Dixon-fat and Dixon-water generated by two-point Dixon water/fat separation, and R2* (1/T2*) map, were also created. To identify informative inputs for generating a pseudo-CT image volume, all 63 combinations, choosing one to six of the feature images, were used as inputs to FCM for pseudo-CT generation. Further, the number of clusters was varied from four to seven to find the optimal approach. Mean prediction deviation (MPD), mean absolute prediction deviation (MAPD), and correlation coefficient (R) of different combinations were compared for feature selection. Results: Among the 63 feature combinations, the four that resulted in the best MAPD and R were further compared along with the set containing all six features. The results suggested that R2* and Dixon-water are the most informative features. Further, including FID also improved the performance of pseudo-CT generation. Consequently, the set containing FID, Dixon-water, and R2* resulted in the most accurate, robust pseudo-CT when the number of cluster equals to five (5C). The clusters were interpreted as air, fat, bone, brain, and fluid. The six-cluster Result additionally included bone marrow. Conclusion: The results suggested that FID, Dixon-water, R2* are the most important features. The findings can be used to

  20. Features of ODEs derived from an autonomous surface ozone network in coastal Antarctica

    Science.gov (United States)

    Jones, A. E.; Wolff, E. W.; Bauguitte, S. J.-B.; Brough, N.

    2012-04-01

    In 2008, a network of 10 autonomous ozone monitors was established around Dronning Maud Land, Antarctica, along 800 km of the coastal perimeter and with a transect running ~450 km up onto the polar plateau. The monitors ran for a full year. The aim of the network was to explore variability of ozone at the different sites, and the contrasting influences of O3 production (arising from snowpack photochemistry) and O3 destruction driven by halogen chemistry. While ozone depletion events have been much studied at single coastal locations, and even from within a large ozone depleted air mass over the Arctic Ocean, a different approach is required to gain information on their spatial extent. The autonomous network provided an opportunity to map the movement, and thereby the size, of ozone-depleted air masses. Here we present results from the network, focusing particularly on activity during springtime. In many cases the same ODE appeared at several (in some cases, all) of the coastal sites, the arrival and departure of the depleted air mass being offset in time. In some instances a severe ODE was evident at a single coastal site only. We explore the meteorological conditions operative during the ODEs as a means of accounting for these observations, and estimate the size of the depleted air masses. Further, we use our data to explore how far inland ODEs can penetrate to address why these are thus far seen as coastal phenomena only. An awareness of the variability in ODEs, spatially as well as temporally, will be necessary for trend studies using coastal polar surface ozone measurements.

  1. Quantitative correlation between air induced changes of electronic parameters and morphological features of copper phthalocyanine thin film surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Grządziel, L., E-mail: Lucyna.Grzadziel@polsl.pl; Krzywiecki, M.

    2015-01-15

    In this work, utilizing fine-resolved photoemission yield spectroscopy (PYS) method, the set of electronic parameters of the space charge layer of 16 nm-copper phthalocyanine (CuPc) thin films deposited on n-type Si(111) substrate covered with modified SiO{sub 2} was determined after long term air exposure. The PYS investigation revealed that work function and surface band bending increased upon gas adsorption by 0.64 eV and 0.32 eV respectively for organic layer and surface dipole effect appeared as the shift in electron affinity of 0.32 eV. Obtained results were compared with photoemission data received for corresponding CuPc films on different types of silicon Si(111) substrate. Collected parameters were correlated with the morphological features of the CuPc's surfaces measured applying atomic force microscopy (AFM) ability. Results of compiled PYS and AFM studies indicated particular electronic tendency for oxidation processes for certain shapes of phthalocyanine crystallites. It may suggest that by manipulation of the initial films' morphology it would be possible to control the air stability of the CuPc-based electronic devices and their vulnerability to degradation processes. - Highlights: • PYS study of 16 nm-CuPc/RCA-SiO{sub 2}/n-Si(111) electronic properties after air exposure. • eV{sub s}, χ{sub s}, φ changes due to oxidation process compared to the other CuPc results. • Electronic parameters shift correlated with morphological features obtained by AFM.

  2. Linear-scaling generation of potential energy surfaces using a double incremental expansion

    CERN Document Server

    König, Carolin

    2016-01-01

    We present a combination of the incremental expansion of potential energy surfaces (PESs), known as n-mode expansion, with the incremental evaluation of the electronic energy in a many-body approach. The application of semi-local coordinates in this context allows the generation of PESs in a very cost-efficient way. For this, we employ the recently introduced FALCON (Flexible Adaptation of Local COordinates of Nuclei) coordinates. By introducing an additional transformation step, concerning only a fraction of the vibrational degrees of freedom, we can achieve linear scaling of the accumulated cost of the single point calculations required in the PES generation. Numerical examples of these double incremental approaches for oligo-phenyl examples show fast convergence with respect to the maximum number of simultaneously treated fragments and only a modest error introduced by the additional transformation step. The approach, presented here, represents a major step towards the applicability of vibrational wave fun...

  3. Computer generated hologram null test of a freeform optical surface with rectangular aperture

    Science.gov (United States)

    Su, Ping; Ma, Jianshe; Tan, Qiaofeng; Kang, Guoguo; Liu, Yi; Jin, Guofan

    2012-02-01

    In null computed generated hologram (CGH) test of optical elements, fitting method is needed in null CGH design to generate continuous phase function from the ray-traced discrete phase data. The null CGH for freeform testing usually has a deformed aperture and a high order phase function, because of the aberrations introduced by freeform wavefront propagation. With traditional Zernike polynomial fitting method, selection of an orthogonal basis set and choosing number of terms are needed before fitting. Zernike polynomial fitting method is not suitable in null CGH design for freeform testing; a novel CGH design method with cubic B-spline interpolation is developed. For a freeform surface with 18×18 mm2 rectangular aperture and 630 μm peak-to-valley undulation, the null CGH with a curved rectangular aperture is designed by using the method proposed. Simulation and experimental results proved the feasibility of the novel CGH design method.

  4. Automated Generation of Digital Terrain Model using Point Clouds of Digital Surface Model in Forest Area

    Directory of Open Access Journals (Sweden)

    Yoshikazu Kamiya

    2011-04-01

    Full Text Available At present, most of the digital data acquisition methods generate Digital Surface Model (DSM and not a Digital Elevation Model (DEM. Conversion from DSM to DEM still has some drawbacks, especially the removing of off terrain point clouds and subsequently the generation of DEM within these spaces even though the methods are automated. In this paper it was intended to overcome this issue by attempting to project off terrain point clouds to the terrain in forest areas using Artificial Neural Networks (ANN instead of removing them and then filling gaps by interpolation. Five sites were tested and accuracies assessed. They all give almost the same results. In conclusion, the ANN has ability to obtain the DEM by projecting the DSM point clouds and greater accuracies of DEMs were obtained. If the size of the hollow areas resulting from the removal of DSM point clouds are larger the accuracies are reduced.

  5. High-frequency Surface Wave Measurements of Micro-tunamis generated by Glacier Calving

    Science.gov (United States)

    Minowa, Masahiro; Sugiyama, Shin; Sakakibara, Daiki; Podolskiy, Evgeny; Ohashi, Yoshihiko; Skvarca, Pedro

    2016-04-01

    Calving plays a key role in recent rapid retreat of glaciers in Greenland, Alaska and Patagonia. However, processes related to calving are poorly understood since direct observations are difficult. When calving occurred at the glacier front, ice hits water surface and generates surface wave or micro-tsunami. Because characteristics of the micro-tsunami are dependent on the impact on water, it is expected that analysis of the wave provides useful information on the size and type of calving. To study the calving processes from surface wave, we performed field observations at Glaciar Perito Moreno, a freshwater calving glacier in the Southern Patagonia Icefield. We measured the surface level by recording water pressure every 2 s (0.5 Hz), using a sensor installed in a lake 300 m from the calving front. Spectral and statistical analyses were performed on the wave data. We also carried out time-lapse photography, ice speed and water temperature measurements. The time-lapse photographs were used to identify the types of observed calving events (1. Subaqueous, 2. Topple, 3. Drop, 4. Small serac failure). During summer (15 December 2013-4 January 2014) and spring (6-20 October 2014) field campaigns, 640 (30 events d-1) and 195 (12 events d-1) calving events were recorded by the pressure sensor, respectively. The number of calving events varied in time (from 0 to 6 events h-1) and this variation correlates well with lakewater temperature. Subaqueous calving account for only 2.4 % of calving events recorded during the field campaigns (7 out of 364 events). These results imply importance of melting at/under water surface as a triggering mechanism of calving. Waves generated by subaerial calving events (type 2, 3 and 4) showed similar frequency spectrums, whereas those by subaqueous calving had smaller power in frequency range between 0.12-0.25 Hz. The amplitude of the surface waves increased with size of calving, which was quantified by the time-lapse photographs. Our results

  6. A graphical solution in CATIA for profiling end mill tool which generates a helical surface

    Science.gov (United States)

    Teodor, V. G.; Baroiu, N.; Berbinschi, S.; Susac, F.; Oancea, N.

    2017-08-01

    The generation of a helical flute, which belongs to a helical cylindrical surface with constant pitch, can be made using end mill tools. The tools on this type are easiest to make than the side mills and represent a less expensive solution. The end mill profiling may be done using the classical theorems of surfaces enveloping, analytical expressed, as Olivier theorem or Nikolaev method. In this paper is proposed an algorithm, developed in the CATIA design environment, for profiling such tool’s type. The proposed solution is intuitive, rigorous and fast due to the utilization of the graphical design environment capabilities. Numerical examples are considered in order to validate the quality of this method.

  7. Dynamics of surface plasma generation by the microsecond emission of the XeF laser

    Science.gov (United States)

    Min'ko, L. Ia.; Chumakov, A. N.; Efremov, V. V.; Bakeev, A. A.; Nikolashina, L. I.; Prokopenko, N. V.; Sorokin, V. A.

    1991-06-01

    The dynamics of surface plasma generation by the microsecond emission of the XeF laser and the interaction of the ultraviolet emission with absorbent materials and the plasma at atmospheric pressure were investigated experimentally. The XeF laser used in the experiments operated at a wavelength of 0.35 micron, with a maximum emergy of 30 J and a pulse width of 3 microsec; the target materials included aluminum, bismuth, and graphite. The experimental results are presented in graphic form and compared with theoretical data.

  8. Surfaces and Curves Corresponding to the Solutions Generated from Periodic “Seed” of NLS Equation

    Institute of Scientific and Technical Information of China (English)

    Ling ZHANG; Jing Song HE; Yi CHENG; Yi Shen LI

    2012-01-01

    The solutions q[n] generated from a periodic “seed” q =cei(as+bt) of the nonlinear Schr(o)dinger (NLS) by n-fold Darboux transformation is represented by determinant.Furthermore,the s-periodic solution and t-periodic solution are given explicitly by using q[1].The curves and surfaces (F1,F2,F3) associated with q[n] are given by means of Sym formula.Meanwhile,we show periodic and asymptotic properties of these curves.

  9. Fast calculation method of computer-generated cylindrical hologram using wave-front recording surface.

    Science.gov (United States)

    Zhao, Yu; Piao, Mei-lan; Li, Gang; Kim, Nam

    2015-07-01

    Fast calculation method for a computer-generated cylindrical hologram (CGCH) is proposed. The method consists of two steps: the first step is a calculation of a virtual wave-front recording surface (WRS), which is located between the 3D object and CGCH. In the second step, in order to obtain a CGCH, we execute the diffraction calculation based on the fast Fourier transform (FFT) from the WRS to the CGCH, which are in the same concentric arrangement. The computational complexity is dramatically reduced in comparison with direct integration method. The simulation results confirm that our proposed method is able to improve the computational speed of CGCH.

  10. Definition And Interpolation Of Discrete Metric For Mesh Generation On 3d Surfaces

    OpenAIRE

    Barbara Głut; Tomasz Jurczyk

    2005-01-01

    The article concerns the problem of a definition of the control space from a set of discretedata (metric description gathered from different sources) and its influence on the efficiency ofthe generation process with respect to 2D and 3D surface meshes. Several methods of metricinterpolation between these discrete points are inspected, including an automated selectionof proper method. Some aspects of the procedures of creation and employment of the meshcontrol space based on the discrete set of poi...

  11. Definition And Interpolation Of Discrete Metric For Mesh Generation On 3d Surfaces

    Directory of Open Access Journals (Sweden)

    Barbara Głut

    2005-01-01

    Full Text Available The article concerns the problem of a definition of the control space from a set of discretedata (metric description gathered from different sources and its influence on the efficiency ofthe generation process with respect to 2D and 3D surface meshes. Several methods of metricinterpolation between these discrete points are inspected, including an automated selectionof proper method. Some aspects of the procedures of creation and employment of the meshcontrol space based on the discrete set of points are presented. The results of using differentvariations of these methods are also included.

  12. Size Effects on Surface Elastic Waves in a Semi-Infinite Medium with Atomic Defect Generation

    Directory of Open Access Journals (Sweden)

    F. Mirzade

    2013-01-01

    Full Text Available The paper investigates small-scale effects on the Rayleigh-type surface wave propagation in an isotopic elastic half-space upon laser irradiation. Based on Eringen’s theory of nonlocal continuum mechanics, the basic equations of wave motion and laser-induced atomic defect dynamics are derived. Dispersion equation that governs the Rayleigh surface waves in the considered medium is derived and analyzed. Explicit expressions for phase velocity and attenuation (amplification coefficients which characterize surface waves are obtained. It is shown that if the generation rate is above the critical value, due to concentration-elastic instability, nanometer sized ordered concentration-strain structures on the surface or volume of solids arise. The spatial scale of these structures is proportional to the characteristic length of defect-atom interaction and increases with the increase of the temperature of the medium. The critical value of the pump parameter is directly proportional to recombination rate and inversely proportional to deformational potentials of defects.

  13. Investigation of the surface generation mechanism of mechanical polishing engineering ceramics using discrete element method

    Science.gov (United States)

    Han, Xuesong

    2014-09-01

    Machining technology about ceramics has been developed very fast over recent years due to the growing industrial demand of higher machining accuracy and better surface quality of ceramic elements, while the nature of hard and brittle ceramics makes it difficult to acquire damage-free and ultra-smooth surface. Ceramic bulk can be treated as an assemblage of discrete particles bonded together randomly as the micro-structure of ceramics consists of crystal particles and pores, and the inter-granular fracture of the ceramics can be naturally represented by the separation of particles due to breakage of bonds. Discrete element method (DEM) provides a promising approach for constructing an effective model to describe the tool-workpiece interaction and can serve as a predicting simulation tool in analyzing the complicated surface generation mechanism and is employed in this research to simulate the mechanical polishing process of ceramics and surface integrity. In this work, a densely packed particle assembly system of the polycrystalline Si3N4 has been generated using bonded-particle model to represent the ceramic workpiece numerically. The simulation results justify that the common critical depth of cut cannot be used as the effective parameters for evaluating brittle to ductile transformation in ceramic polishing process. Therefore, a generalized criterion of defining the range of ductile regime machining has been developed based on the numerical results. Furthermore, different distribution of pressure chain is observed with different depth of cut which ought to have intense relationship with special structure of ceramics. This study also justified the advantage of DEM model in its capability of revealing the mechanical behaviors of ceramics at micro-scale.

  14. Slip effect on stagnation point flow past a stretching surface with the presence of heat generation/absorption and Newtonian heating

    Science.gov (United States)

    Mohamed, Muhammad Khairul Anuar; Noar, Nor Aida Zuraimi Md; Ismail, Zulkhibri; Kasim, Abdul Rahman Mohd; Sarif, Norhafizah Md; Salleh, Mohd Zuki; Ishak, Anuar

    2017-08-01

    Present study solved numerically the velocity slip effect on stagnation point flow past a stretching surface with the presence of heat generation/absorption and Newtonian heating. The governing equations which in the form of partial differential equations are transformed to ordinary differential equations before being solved numerically using the Runge-Kutta-Fehlberg method in MAPLE. The numerical solution is obtained for the surface temperature, heat transfer coefficient, reduced skin friction coefficient as well as the temperature and velocity profiles. The flow features and the heat transfer characteristic for the pertinent parameter such as Prandtl number, stretching parameter, heat generation/absorption parameter, velocity slip parameter and conjugate parameter are analyzed and discussed.

  15. Long‐term TIR imagery processing for spatiotemporal monitoring of surface thermal features in volcanic environment: A case study in the Campi Flegrei (Southern Italy)

    National Research Council Canada - National Science Library

    Vilardo, G; Sansivero, F; Chiodini, G

    2015-01-01

    ...‐surface thermal features of an area affected by diffuse degassing. Long‐term infrared time series images were processed without taking into account atmospheric conditions and emissivity estimations...

  16. Characterization of Si(1 1 1){radical}(3) Multiplication-Sign {radical}(3)-(Au,In) surface by optical second-harmonic generation

    Energy Technology Data Exchange (ETDEWEB)

    Ignatovich, K.V. [Institute of Automation and Control Processes, 5 Radio Street, 690041 Vladivostok (Russian Federation); Zotov, A.V. [Institute of Automation and Control Processes, 5 Radio Street, 690041 Vladivostok (Russian Federation); School of Natural Sciences, Far Eastern Federal University, 690950 Vladivostok (Russian Federation); Department of Electronics, Vladivostok State University of Economics and Service, 690600 Vladivostok (Russian Federation); Saranin, A.A. [Institute of Automation and Control Processes, 5 Radio Street, 690041 Vladivostok (Russian Federation); School of Natural Sciences, Far Eastern Federal University, 690950 Vladivostok (Russian Federation)

    2012-03-01

    We investigated the change of optical second harmonic generation (SHG) intensity in the course of Si(1 1 1){radical}(3) Multiplication-Sign {radical}(3)-(Au,In) surface formation and during subsequent In island growth on this surface. The Si(1 1 1){radical}(3) Multiplication-Sign {radical}(3)-(Au,In) surface is essentially a modified Si(1 1 1)-{alpha}-{radical}(3) Multiplication-Sign {radical}(3)-Au surface in which the domain-wall network (characteristic of the original surface) is completely eliminated due to In adsorption. This surface shows up as the one having homogeneous highly ordered atomic structure. Its formation is accompanied by the extremely high (namely, tenfold) increase of the SHG signal. It was recognized that this increase is associated with an extraordinary high long-range atomic ordering of the Si(1 1 1){radical}(3) Multiplication-Sign {radical}(3)-(Au,In) surface, while its other peculiar features, developing the 2D electron gas system and occurrence of the 2D gas of mobile adatoms on it, produce minor effects. Growth of random In islands on Si(1 1 1){radical}(3) Multiplication-Sign {radical}(3)-(Au,In) at RT In deposition leads to the decrease of SHG signal indicating its sensitivity to the surface inhomogeneity not only in atomic scale but in the mesascopic scale also.

  17. Verification of muscle fatigue detection capability of unipolar and bipolar lead systems using surface EMG generation model

    OpenAIRE

    堀田, 優; 小浦方, 裕騎; 伊藤, 建一; Hotta, Yu; Kourakata, Yuki; Ito, Kenichi

    2013-01-01

    In this study, we constructed a simulation model to generate a surface EMG during isometric exercise. The surface EMG was detected using both unipolar and bipolar lead systems, and the measurement performance of both systems was compared. When detecting surface EMGs using the unipolar lead system, low-frequency components were increased to a greater extent than in the bipolar lead system, suggesting that the unipolar lead system is more suitable for the detection of surface EMGs

  18. Acoustic nonlinearity of narrowband laser-generated surface waves in the bending fatigue of Al6061 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Taehyung; Choi, Sungho; Lee, Taehun; Jhang, Kyungyoung; Kim, Chungseok [Hanyang University, Seoul (Korea, Republic of)

    2010-11-15

    The present study describes the acoustic nonlinearity phenomenon of a narrowband laser generated surface wave for the characterization of an aluminum alloy subjected to bending fatigue. The surface wave is very attractive for field applications because it does not require both sides of the test materials to access the transducers and has strong acoustic nonlinear effects on the surface. The intrinsic higher-order harmonic components generated by a line-arrayed laser beam have been analyzed theoretically, and a relative acoustic nonlinear parameter has been successfully measured on the surface of a fatigue-damaged aluminum 6061 alloy. The results show that the acoustic nonlinear parameter increased after fatigue damage with respect to dislocation evolution. Consequently, this study suggests that the new acoustic nonlinearity technique of a laser-generated surface wave can be potentially used to characterize surface damage resulting from bending fatigue prior to the formation of fatigue cracks.

  19. Rendering of surface-geometries at job-generation level for camouflaging the layered nature of Additively Manufactured parts

    DEFF Research Database (Denmark)

    Pedersen, D. B.; Hansen, H. N.; Nielsen, J. S.

    2014-01-01

    . An often used method for visualization of complex geometries within CGI is by producing a geometrical primitive after which the primitive is passed through a renderer.[2] Examples can be geometries with hair, leather structure and their like. Should the entire geometry including surface definition sought......] It is proposed to camouflage these layers in order to produce parts with a better visual appeal, and to add functional surface structures. In order to generate such surface structures without adding a challenging computational overhead at job-generation, inspiration from Computer Generated Imaging (CGI) is found...

  20. Switching Transient Generation in Surface Interrogation Scanning Electrochemical Microscopy and Time-of-Flight Techniques.

    Science.gov (United States)

    Ahn, Hyun S; Bard, Allen J

    2015-12-15

    In surface interrogation scanning electrochemical microscopy (SI-SECM), fine and accurate control of the delay time between substrate generation and tip interrogation (tdelay) is crucial because tdelay defines the decay time of the reactive intermediate. In previous applications of the SI-SECM, the resolution in the control of tdelay has been limited to several hundreds of milliseconds due to the slow switching of the bipotentiostat. In this work, we have improved the time resolution of tdelay control up to ca. 1 μs, enhancing the SI-SECM to be competitive in the time domain with the decay of many reactive intermediates. The rapid switching SI-SECM has been implemented in a substrate generation-tip collection time-of-flight (SG-TC TOF) experiment of a solution redox mediator, and the results obtained from the experiment exhibited good agreement with that obtained from digital simulation. The reaction rate constant of surface Co(IV) on oxygen-evolving catalyst film, which was inaccessible thus far due to the lack of tdelay control, has been measured by the rapid switching SI-SECM.

  1. Studies of thin films and surfaces with optical harmonic generation and electron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wilk, Dieter Emre [Univ. of California, Berkeley, CA (United States)

    1996-01-01

    Optical second harmonic generation (SHG) and sum frequency generation (SFG) were used to study C60 thin solid films (low energy ED forbidden electronic excitations), and electron spectroscopy was used to study organic overlayers (xylenes) on Pt(111). Theory of SHG from a thin film is described in terms of surface and bulk contributions as well as local and nonlocal contributions to the optical nonlinearities. (1)In situ SHG data on C60 films during UHV film growth can be described in terms of only nonlocal contributions to both surface and bulk nonlinear susceptibilities. Microscopic origin of SHG response is discussed in terms of electric quadrupole and ED transitions of C60. (2)Adsorption and thermal decomposition of ortho- and para-xylene on Pt(111) is studied using HREELS, LEED, AES, and thermal desorption spectroscopy. We have observed preferential decomposition of the methyl groups which leads to distinct decomposition pathways for ortho- and para-xylene on Pt(111).

  2. Enhanced third harmonic generation using the surface states of light in periodic photonic structures

    Science.gov (United States)

    Zaytsev, Kirill I.; Gorelik, Vladimir S.; Katyba, Gleb M.; Yurchenko, Stanislav O.

    2014-10-01

    Third harmonic generation enhancement in periodic photonic structures was experimentally observed and theoretically interpreted. Nonlinear optical effects in opal globular photonic crystals (PC) have been studied under the femtosecond laser pumping. Strong dependence of the third harmonic generation efficiency on the ratio between the central pumping wavelength and the spectral location of the PC band gaps was found. Numerical simulations based on the finite difference time-domain technique for the solution of the Maxwell's equations were applied for investigations of the observed phenomenon origin. The simulation results have shown that the origin of the efficient nonlinear conversion is related with the surface state of electromagnetic field in PC. Interacting with the PC surface the light wavefront distorts coherently, and the effect of structure light focusing appears. Coherent wavefront distortion leads to the strong optical field localization, hence the light intensity within the certain PC regions increases. In case of the band gap pumping dramatic light redistribution appears; very sharp peaks of light intensity emerge in the region of the quartz globules, which leads to the high-efficient PC pumping.

  3. Spatial features of dose-surface maps from deformably-registered plans correlate with late gastrointestinal complications

    Science.gov (United States)

    Moulton, Calyn R.; House, Michael J.; Lye, Victoria; Tang, Colin I.; Krawiec, Michele; Joseph, David J.; Denham, James W.; Ebert, Martin A.

    2017-05-01

    This study investigates the associations between spatial distribution of dose to the rectal surface and observed gastrointestinal toxicities after deformably registering each phase of a combined external beam radiotherapy (EBRT)/high-dose-rate brachytherapy (HDRBT) prostate cancer treatment. The study contains data for 118 patients where the HDRBT CT was deformably-registered to the EBRT CT. The EBRT and registered HDRBT TG43 dose distributions in a reference 2 Gy/fraction were 3D-summed. Rectum dose-surface maps (DSMs) were obtained by virtually unfolding the rectum surface slice-by-slice. Associations with late peak gastrointestinal toxicities were investigated using voxel-wise DSM analysis as well as parameterised spatial patterns. The latter were obtained by thresholding DSMs from 1-80 Gy (increment  =  1) and extracting inferior-superior extent, left-right extent, area, perimeter, compactness, circularity and ellipse fit parameters. Logistic regressions and Mann-Whitney U-tests were used to correlate features with toxicities. Rectal bleeding, stool frequency, diarrhoea and urgency/tenesmus were associated with greater lateral and/or longitudinal spread of the high doses near the anterior rectal surface. Rectal bleeding and stool frequency were also influenced by greater low-intermediate doses to the most inferior 20% of the rectum and greater low-intermediate-high doses to 40-80% of the rectum length respectively. Greater low-intermediate doses to the superior 20% and inferior 20% of the rectum length were associated with anorectal pain and urgency/tenesmus respectively. Diarrhoea, completeness of evacuation and proctitis were also related to greater low doses to the posterior side of the rectum. Spatial features for the intermediate-high dose regions such as area, perimeter, compactness, circularity, ellipse eccentricity and confinement to ellipse fits were strongly associated with toxicities other than anorectal pain. Consequently, toxicity is

  4. Spatial and Temporal Homogeneity of Solar Surface Irradiance across Satellite Generations

    Directory of Open Access Journals (Sweden)

    Rebekka Posselt

    2011-05-01

    Full Text Available Solar surface irradiance (SIS is an essential variable in the radiation budget of the Earth. Climate data records (CDR’s of SIS are required for climate monitoring, for climate model evaluation and for solar energy applications. A 23 year long (1983–2005 continuous and validated SIS CDR based on the visible channel (0.45–1 μm of the MVIRI instruments onboard the first generation of Meteosat satellites has recently been generated using a climate version of the well established Heliosat method. This version of the Heliosat method includes a newly developed self-calibration algorithm and an improved algorithm to determine the clear sky reflection. The climate Heliosat version is also applied to the visible narrow-band channels of SEVIRI onboard the Meteosat Second Generation Satellites (2004–present. The respective channels are observing the Earth in the wavelength region at about 0.6 μm and 0.8 μm. SIS values of the overlapping time period are used to analyse whether a homogeneous extension of the MVIRI CDR is possible with the SEVIRI narrowband channels. It is demonstrated that the spectral differences between the used visible channels leads to significant differences in the solar surface irradiance in specific regions. Especially, over vegetated areas the reflectance exhibits a high spectral dependency resulting in large differences in the retrieved SIS. The applied self-calibration method alone is not able to compensate the spectral differences of the channels. Furthermore, the extended range of the input values (satellite counts enhances the cloud detection of the SEVIRI instruments resulting in lower values for SIS, on average. Our findings have implications for the application of the Heliosat method to data from other geostationary satellites (e.g., GOES, GMS. They demonstrate the need for a careful analysis of the effect of spectral and technological differences in visible channels on the retrieved solar irradiance.

  5. Efficient generation of Heisenberg Hamiltonian matrices for VB calculations of potential energy surfaces

    Science.gov (United States)

    Tokmachev, A. M.; Robb, M. A.

    The spin-Hamiltonian valence bond theory relies upon covalent configurations formed by singly occupied orbitals differing by their spin counterparts. This theory has been proven to be successful in studying potential energy surfaces of the ground and lowest excited states in organic molecules when used as a part of the hybrid molecular mechanics - valence bond method. The method allows one to consider systems with large active spaces formed by n electrons in n orbitals and relies upon a specially proposed graphical unitary group approach. At the same time, the restriction of the equality of the numbers of electrons and orbitals in the active space is too severe: it excludes from the consideration a lot of interesting applications. We can mention here carbocations and systems with heteroatoms. Moreover, the structure of the method makes it difficult to study charge-transfer excited states because they are formed by ionic configurations. In the present work we tackle these problems by significant extension of the spin-Hamiltonian approach. We consider (i) more general active space formed by n ± m electrons in n orbitals and (ii) states with the charge transfer. The main problem addressed is the generation of Hamiltonian matrices for these general cases. We propose a scheme combining operators of electron exchange and hopping, generating all nonzero matrix elements step-by-step. This scheme provides a very efficient way to generate the Hamiltonians, thus extending the applicability of spin-Hamiltonian valence bond theory.

  6. NANOSCALE STRUCTURES GENERATION WITHIN THE SURFACE LAYER OF METALS WITH SHORT UV LASER PULSES

    Directory of Open Access Journals (Sweden)

    Dmitry S. Ivanov

    2017-01-01

    Full Text Available We have completed modeling of a laser pulse influence on a gold target. We have applied a hybrid atomistic-continuum model to analyze the physical mechanisms responsible for the process of nanostructuring. The model combines the advantages of Molecular Dynamics and Two Temperature Model. We have carried out a direct comparison of the modeling results and experimental data on nano-modification due to a single ps laser pulse at the energy densities significantly exceeding the melting threshold. The experimental data is obtained due to a laser pulse irradiation at the wavelength of 248 nm and duration of 1.6 ps. The mask projection (diffraction grating creates the sinusoidal intensity distribution on a gold surface with periods of 270 nm, 350 nm, and 500 nm. The experimental data and modeling results have demonstrated a good match subject to complex interrelations between a fast material response to the laser excitation, generation of crystal defects, phase transitions and hydrodynamic motion of matter under condition of strong laser-induced non-equilibrium. The performed work confirms the proposed approach as a powerful tool for revealing the physical mechanisms underlying the process of nanostructuring of metal surfaces. Detailed understanding of the dynamics of these processes gives the possibility for designing the topology of functional surfaces on nano- and micro-scales.

  7. Field enhancement at silicon surfaces by gold ellipsoids probed by optical second-harmonic generation spectroscopy

    Science.gov (United States)

    Ulriksen, Hans Ulrik; Pedersen, Kjeld

    2016-12-01

    Optical second-harmonic generation (SHG) spectroscopy has been used to determine the field enhancements from Au nanoparticles on a silicon substrate. Au particles with diameters from 30 to 250 nm have been deposited on a Si substrate passivated by a 1 nm thick surface oxide. The linear optical spectra are dominated by a horizontal plasmon resonance near 1.0 eV, and the experimental spectra are modelled by the island film model in order to extract the linear properties of the metal particles. SHG spectroscopy from this system shows resonances from the metal particles and from the silicon/oxide substrate. By following the evolution of these Si resonances with the size of the Au particles, the field enhancement in the Si surface has been modelled. The effect of the Au particles on SHG at the Si E1 resonance is a combination of charge transfer through the thin oxide that changes the space charge region and an enhancement of the optical field in a thin surface layer of the Si substrate.

  8. Nanoscale surface analysis on second generation advanced high strength steel after hot dip galvanizing.

    Science.gov (United States)

    Arndt, M; Duchoslav, J; Preis, K; Samek, L; Stifter, D

    2013-09-01

    Second generation advanced high strength steel is one promising material of choice for modern automotive structural parts because of its outstanding maximal elongation and tensile strength. Nonetheless there is still a lack of corrosion protection for this material due to the fact that cost efficient hot dip galvanizing cannot be applied. The reason for the insufficient coatability with zinc is found in the segregation of manganese to the surface during annealing and the formation of manganese oxides prior coating. This work analyses the structure and chemical composition of the surface oxides on so called nano-TWIP (twinning induced plasticity) steel on the nanoscopic scale after hot dip galvanizing in a simulator with employed analytical methods comprising scanning Auger electron spectroscopy (SAES), energy dispersive X-ray spectroscopy (EDX), and focused ion beam (FIB) for cross section preparation. By the combination of these methods, it was possible to obtain detailed chemical images serving a better understanding which processes exactly occur on the surface of this novel kind of steel and how to promote in the future for this material system galvanic protection.

  9. Problems on design of computer-generated holograms for testing aspheric surfaces: principle and calculation

    Institute of Scientific and Technical Information of China (English)

    Zhishan Gao; Meimei Kong; Rihong Zhu; Lei Chen

    2007-01-01

    Interferometric optical testing using computer-generated hologram (CGH) has provided an approach to highly accurate measurement of aspheric surfaces. While designing the CGH null correctors, we should make them with as small aperture and low spatial frequency as possible, and with no zero slope of phase except at center, for the sake of insuring lowisk of substrate figure error and feasibility of fabrication. On the basis of classic optics, a set of equations for calculating the phase function of CGH are obtained. These equations lead us to find the dependence of the aperture and spatial frequency on the axial diszance from the tested aspheric surface for the CGH. We also simulatethe ptical path difference error of the CGH relative to the accuracy of controlling laser spot during fabrication. Meanwhile, we discuss the constraints used to avoid zero slope of phase except at center and give a design result of the CGH for the tested aspheric surface. The results ensure the feasibility of designing a useful CGH to test aspheric urface fundamentally.

  10. ANALYSIS OF THE SPECIAL FEATURES OF THE THERMAL PROCESS IN AN INDUCTION GENERATOR AT HIGH SATURATION OF THE MAGNETIC SYSTEM

    Directory of Open Access Journals (Sweden)

    V. Chenchevoi

    2017-06-01

    Full Text Available Purpose. Development of the method for the assessment of the thermal operation modes of an autonomous electrical power system with an induction motor, aiming at improvement of the reliability of electricity supply and the quality of electric energy. Methodology. Induction generator mathematical modeling taking into account the magnetic system saturation was used in the research. A heat model taking into account the excess of the temperature of the induction generator units in the mode of high saturation was developed. The obtained results were compared with the experimental data. Results. The paper contains the solution to the problem of improvement of the mathematical model sand methods for steel losses determination in there search of the operation modes of an autonomous uncontrolled induction generator taking into consideration the properties of the magnetic system in the mode of high saturation. The expression for determination of steel losses in the mode of high saturation is obtained. It enables the assessment of the induction generator thermal condition. Originality. The analytical dependence for the calculation of the steel losses in the mode of magnetic system saturation has been obtained for the first time. Practical value. The obtained expression for the calculation of the steel losses can be used for determination of the admissible time of generator operation at overload. It will allow avoiding broken winding insulation and complete use of the generator overload capacity. As a result, it will reduce possible irregularities of electricity supply due to the generator preliminary cutoff.

  11. A general procedure to generate models for urban environmental-noise pollution using feature selection and machine learning methods.

    Science.gov (United States)

    Torija, Antonio J; Ruiz, Diego P

    2015-02-01

    The prediction of environmental noise in urban environments requires the solution of a complex and non-linear problem, since there are complex relationships among the multitude of variables involved in the characterization and modelling of environmental noise and environmental-noise magnitudes. Moreover, the inclusion of the great spatial heterogeneity characteristic of urban environments seems to be essential in order to achieve an accurate environmental-noise prediction in cities. This problem is addressed in this paper, where a procedure based on feature-selection techniques and machine-learning regression methods is proposed and applied to this environmental problem. Three machine-learning regression methods, which are considered very robust in solving non-linear problems, are used to estimate the energy-equivalent sound-pressure level descriptor (LAeq). These three methods are: (i) multilayer perceptron (MLP), (ii) sequential minimal optimisation (SMO), and (iii) Gaussian processes for regression (GPR). In addition, because of the high number of input variables involved in environmental-noise modelling and estimation in urban environments, which make LAeq prediction models quite complex and costly in terms of time and resources for application to real situations, three different techniques are used to approach feature selection or data reduction. The feature-selection techniques used are: (i) correlation-based feature-subset selection (CFS), (ii) wrapper for feature-subset selection (WFS), and the data reduction technique is principal-component analysis (PCA). The subsequent analysis leads to a proposal of different schemes, depending on the needs regarding data collection and accuracy. The use of WFS as the feature-selection technique with the implementation of SMO or GPR as regression algorithm provides the best LAeq estimation (R(2)=0.94 and mean absolute error (MAE)=1.14-1.16 dB(A)). Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Zinc (hydr)oxide/graphite oxide/AuNPs composites: role of surface features in H₂S reactive adsorption.

    Science.gov (United States)

    Giannakoudakis, Dimitrios A; Bandosz, Teresa J

    2014-12-15

    Zinc hydroxide/graphite oxide/AuNPs composites with various levels of complexity were synthesized using an in situ precipitation method. Then they were used as H2S adsorbents in visible light. The materials' surfaces were characterized before and after H2S adsorption by various physical and chemical methods (XRD, FTIR, thermal analysis, potentiometric titration, adsorption of nitrogen and SEM/EDX). Significant differences in surface features and synergistic effects were found depending on the materials' composition. Addition of graphite oxide and the deposition of gold nanoparticles resulted in a marked increase in the adsorption capacity in comparison with that on the zinc hydroxide and zinc hydroxide/AuNP. Addition of AuNPs to zinc hydroxide led to a crystalline ZnO/AuNP composite while the zinc hydroxide/graphite oxide/AuNP composite was amorphous. The ZnOH/GO/AuNPs composite exhibited the greatest H2S adsorption capacity due to the increased number of OH terminal groups and the conductive properties of GO that facilitated the electron transfer and consequently the formation of superoxide ions promoting oxidation of hydrogen sulfide. AuNPs present in the composite increased the conductivity, helped with electron transfer to oxygen, and prevented the fast recombination of the electrons and holes. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Porphyromonas gingivalis Uses Specific Domain Rearrangements and Allelic Exchange to Generate Diversity in Surface Virulence Factors

    Science.gov (United States)

    Dashper, Stuart G.; Mitchell, Helen L.; Seers, Christine A.; Gladman, Simon L.; Seemann, Torsten; Bulach, Dieter M.; Chandry, P. Scott; Cross, Keith J.; Cleal, Steven M.; Reynolds, Eric C.

    2017-01-01

    Porphyromonas gingivalis is a keystone pathogen of chronic periodontitis. The virulence of P. gingivalis is reported to be strain related and there are currently a number of strain typing schemes based on variation in capsular polysaccharide, the major and minor fimbriae and adhesin domains of Lys-gingipain (Kgp), amongst other surface proteins. P. gingivalis can exchange chromosomal DNA between strains by natural competence and conjugation. The aim of this study was to determine the genetic variability of P. gingivalis strains sourced from international locations over a 25-year period and to determine if variability in surface virulence factors has a phylogenetic basis. Whole genome sequencing was performed on 13 strains and comparison made to 10 previously sequenced strains. A single nucleotide polymorphism-based phylogenetic analysis demonstrated a shallow tri-lobed phylogeny. There was a high level of reticulation in the phylogenetic network, demonstrating extensive horizontal gene transfer between the strains. Two highly conserved variants of the catalytic domain of the major virulence factor the Kgp proteinase (KgpcatI and KgpcatII) were found. There were three variants of the fourth Kgp C-terminal cleaved adhesin domain. Specific variants of the cell surface proteins FimA, FimCDE, MfaI, RagAB, Tpr, and PrtT were also identified. The occurrence of all these variants in the P. gingivalis strains formed a mosaic that was not related to the SNP-based phylogeny. In conclusion P. gingivalis uses domain rearrangements and genetic exchange to generate diversity in specific surface virulence factors. PMID:28184216

  14. Calculating wave-generated bottom orbital velocities from surface-wave parameters

    Science.gov (United States)

    Wiberg, P.L.; Sherwood, C.R.

    2008-01-01

    Near-bed wave orbital velocities and shear stresses are important parameters in many sediment-transport and hydrodynamic models of the coastal ocean, estuaries, and lakes. Simple methods for estimating bottom orbital velocities from surface-wave statistics such as significant wave height and peak period often are inaccurate except in very shallow water. This paper briefly reviews approaches for estimating wave-generated bottom orbital velocities from near-bed velocity data, surface-wave spectra, and surface-wave parameters; MATLAB code for each approach is provided. Aspects of this problem have been discussed elsewhere. We add to this work by providing a method for using a general form of the parametric surface-wave spectrum to estimate bottom orbital velocity from significant wave height and peak period, investigating effects of spectral shape on bottom orbital velocity, comparing methods for calculating bottom orbital velocity against values determined from near-bed velocity measurements at two sites on the US east and west coasts, and considering the optimal representation of bottom orbital velocity for calculations of near-bed processes. Bottom orbital velocities calculated using near-bed velocity data, measured wave spectra, and parametric spectra for a site on the northern California shelf and one in the mid-Atlantic Bight compare quite well and are relatively insensitive to spectral shape except when bimodal waves are present with maximum energy at the higher-frequency peak. These conditions, which are most likely to occur at times when bottom orbital velocities are small, can be identified with our method as cases where the measured wave statistics are inconsistent with Donelan's modified form of the Joint North Sea Wave Project (JONSWAP) spectrum. We define the 'effective' forcing for wave-driven, near-bed processes as the product of the magnitude of forcing times its probability of occurrence, and conclude that different bottom orbital velocity statistics

  15. Superhydrophobic aluminium-based surfaces: Wetting and wear properties of different CVD-generated coating types

    Science.gov (United States)

    Thieme, M.; Streller, F.; Simon, F.; Frenzel, R.; White, A. J.

    2013-10-01

    In view of generating superhydrophobic aluminium-based surfaces, this work presents further results for the combination of anodic oxidation as the primary pretreatment method and chemical vapour deposition (CVD) variants for chemical modification producing coatings of 250-1000 nm thickness. In detail, CVD involved the utilisation of i - hexafluoropropylene oxide as precursor within the hot filament CVD process for the deposition of poly(tetrafluoroethylene) coatings at alternative conditions (PTFE-AC) and ii - 1,3,5-trivinyltrimethylcyclotrisiloxane for the deposition of polysiloxane coatings (PSi) by initiated CVD. The substrate material was Al Mg1 subjected to usual or intensified sulphuric acid anodisation pretreatments (SAAu, SAAi, respectively) affording various degrees of surface micro-roughness (SAAu weathering and/or mild wear testing. Superhydrophobicity (SH) was observed with the system SAAi + PTFE-AC similarly to former findings with the standard hot filament CVD PTFE coating variant (SAAi + PTFE-SC). The results indicated that the specific coating morphology made an important contribution to the water-repellency, because even some of the SAAu-based samples tended to reveal SH. Subjecting samples to weathering treatment resulted in a general worsening of the wetting behaviour, primarily limited to the receding contact angles. These tendencies were correlated with the chemical composition of the sample surfaces as analysed by X-ray photoelectron spectroscopy. The wear tests showed, as evaluated by scanning electron microscopy and contact angle measurement, that the PTFE coatings were relatively sensitive to friction. This was connected with a dramatic deterioration of the water-repelling properties. PSi-coated surfaces generally showed rather poor water-repellency, but this coating type was surprisingly resistant towards the applied friction test. From these findings it may be concluded that the combination of hydrophobic fluorine containing structure

  16. Generations.

    Science.gov (United States)

    Chambers, David W

    2005-01-01

    Groups naturally promote their strengths and prefer values and rules that give them an identity and an advantage. This shows up as generational tensions across cohorts who share common experiences, including common elders. Dramatic cultural events in America since 1925 can help create an understanding of the differing value structures of the Silents, the Boomers, Gen Xers, and the Millennials. Differences in how these generations see motivation and values, fundamental reality, relations with others, and work are presented, as are some applications of these differences to the dental profession.

  17. Directional and singular surface plasmon generation in chiral and achiral nanostructures demonstrated by Leakage Radiation Microscopy

    CERN Document Server

    Jiang, Quanbo; Berthel, Martin; Huant, Serge; Bellessa, Joel; Genet, Cyriaque; Drezet, Aurélien

    2016-01-01

    In this paper, we describe the implementation of leakage radiation microscopy (LRM) to probe the chirality of plasmonic nanostructures. We demonstrate experimentally spin-driven directional coupling as well as vortex generation of surface plasmon polaritons (SPPs) by nanostructures built with T-shaped and $\\Lambda$- shaped apertures. Using this far-field method, quantitative inspections, including directivity and extinction ratio measurements, are achieved via polarization analysis in both image and Fourier planes. To support our experimental findings, we develop an analytical model based on a multidipolar representation of $\\Lambda$- and T-shaped aperture plasmonic coupler allowing a theoretical explanation of both directionality and singular SPP formation. Furthermore, the roles of symmetry breaking and phases are emphasized in this work. This quantitative characterization of spin-orbit interactions paves the way for developing new directional couplers for subwavelength routing.

  18. Entropy Generation on MHD Casson Nanofluid Flow over a Porous Stretching/Shrinking Surface

    Directory of Open Access Journals (Sweden)

    Jia Qing

    2016-04-01

    Full Text Available In this article, entropy generation on MHD Casson nanofluid over a porous Stretching/Shrinking surface has been investigated. The influences of nonlinear thermal radiation and chemical reaction have also taken into account. The governing Casson nanofluid flow problem consists of momentum equation, energy equation and nanoparticle concentration. Similarity transformation variables have been used to transform the governing coupled partial differential equations into ordinary differential equations. The resulting highly nonlinear coupled ordinary differential equations have been solved numerically with the help of Successive linearization method (SLM and Chebyshev spectral collocation method. The impacts of various pertinent parameters of interest are discussed for velocity profile, temperature profile, concentration profile and entropy profile. The expression for local Nusselt number and local Sherwood number are also analyzed and discussed with the help of tables. Furthermore, comparison with the existing is also made as a special case of our study.

  19. Third Generation Horseradish Peroxidase Biosensor Based on Self-assembling Carbon Nanotubes to Gold Electrode Surface

    Institute of Scientific and Technical Information of China (English)

    Jing Juan XU; Gang WANG; Qing ZHANG; Xing Hua XIA; Hong Yuan CHEN

    2005-01-01

    A third-generation horseradish peroxidase (HRP) biosensor has been developed by adsorbing HRP on multi-wall carbon nanotube (MWNTs) monolayer modified gold electrode surface. The assembly process was investigated by electrochemical and spectroscopic techniques.Results showed that the immobilized HRP exhibited direct electrochemical behavior toward the reduction of H2O2. The resulting biosensor shows a fast amperometric response (<2 s) to H2O2.The linear response range was from 5.0×10-7~1.0×10-5 mol/L with a detection limit of1.0×10-7mol/L. Moreover, the biosensor has a good reproducibility, and long-term stability.

  20. Glow and pseudo-glow discharges in a surface discharge generator

    Institute of Scientific and Technical Information of China (English)

    Li Xue-Chen; Dong Li-Fang; Wang Long

    2005-01-01

    The glow discharge in flowing argon at one atmospheric pressure is realized in a surface discharge generator. The discharge current presents one peak per half-cycle of the applied voltage. The duration of the discharge pulse is more than 1μs when the frequency of the applied voltage is 60kHz. For the glow discharge in argon, the power consumption increases with the increase of voltage or the decrease of gas pressure.This relation is explained qualitatively based on the theory of the Townsend breakdown mechanism. In contrast, the discharge current in one atmospheric pressure air gives many spikes in each half-cycle, and correspondingly this kind of discharge is called pseudo-glow discharge. Every current spike oscillates with high-frequency damping. The pseudo-glow discharge in one atmospheric pressure air might result from the streamer breakdown mechanism.