Science.gov

Sample records for embedded characterization technique

  1. Characterizing structural and vibrational properties of nanoparticles embedded in silica with XAS, SAXS and auxiliary techniques

    NASA Astrophysics Data System (ADS)

    Araujo, Leandro L.; Kluth, Patrick; Giulian, Raquel; Sprouster, David J.; Johannessen, Bernt; Foran, Garry J.; Cookson, David J.; Ridgway, Mark C.

    2009-01-01

    Synchrotron-based techniques were combined with conventional analysis methods to probe in detail the structural and vibrational properties of nanoparticles grown in a silica matrix by ion implantation and thermal annealing, as well as the evolution of such properties as a function of nanoparticle size. This original approach was successfully applied for several elemental nanoparticles (Au, Co, Cu, Ge, Pt) and the outcomes for Ge are reported here, illustrating the power of this combined methodology. The thorough analysis of XANES, EXAFS, SAXS, TEM and Raman data for Ge nanoparticles with mean diameters between 4 and 9 nm revealed that the peculiar properties of embedded Ge nanoparticles, like the existence of amorphous Ge layers between the silica matrix and the crystalline nanoparticle core, are strongly dependent on particle size and mainly governed by the variation in the surface area-to-volume ratio. Such detailed information provides valuable input for the efficient planning of technological applications.

  2. Characterizing structural and vibrational properties of nanoparticles embedded in silica with XAS, SAXS and auxiliary techniques

    SciTech Connect

    Araujo, Leandro L.; Kluth, Patrick; Giulian, Raquel; Sprouster, David J.; Ridgway, Mark C.; Johannessen, Bernt; Foran, Garry J.; Cookson, David J.

    2009-01-29

    Synchrotron-based techniques were combined with conventional analysis methods to probe in detail the structural and vibrational properties of nanoparticles grown in a silica matrix by ion implantation and thermal annealing, as well as the evolution of such properties as a function of nanoparticle size. This original approach was successfully applied for several elemental nanoparticles (Au, Co, Cu, Ge, Pt) and the outcomes for Ge are reported here, illustrating the power of this combined methodology. The thorough analysis of XANES, EXAFS, SAXS, TEM and Raman data for Ge nanoparticles with mean diameters between 4 and 9 nm revealed that the peculiar properties of embedded Ge nanoparticles, like the existence of amorphous Ge layers between the silica matrix and the crystalline nanoparticle core, are strongly dependent on particle size and mainly governed by the variation in the surface area-to-volume ratio. Such detailed information provides valuable input for the efficient planning of technological applications.

  3. Dynamic characterization, monitoring and control of rotating flexible beam-mass structures via piezo-embedded techniques

    NASA Technical Reports Server (NTRS)

    Lai, Steven H.-Y.

    1992-01-01

    A variational principle and a finite element discretization technique were used to derive the dynamic equations for a high speed rotating flexible beam-mass system embedded with piezo-electric materials. The dynamic equation thus obtained allows the development of finite element models which accommodate both the original structural element and the piezoelectric element. The solutions of finite element models provide system dynamics needed to design a sensing system. The characterization of gyroscopic effect and damping capacity of smart rotating devices are addressed. Several simulation examples are presented to validate the analytical solution.

  4. A 3-D chimera grid embedding technique

    NASA Technical Reports Server (NTRS)

    Benek, J. A.; Buning, P. G.; Steger, J. L.

    1985-01-01

    A three-dimensional (3-D) chimera grid-embedding technique is described. The technique simplifies the construction of computational grids about complex geometries. The method subdivides the physical domain into regions which can accommodate easily generated grids. Communication among the grids is accomplished by interpolation of the dependent variables at grid boundaries. The procedures for constructing the composite mesh and the associated data structures are described. The method is demonstrated by solution of the Euler equations for the transonic flow about a wing/body, wing/body/tail, and a configuration of three ellipsoidal bodies.

  5. Biometric feature embedding using robust steganography technique

    NASA Astrophysics Data System (ADS)

    Rashid, Rasber D.; Sellahewa, Harin; Jassim, Sabah A.

    2013-05-01

    This paper is concerned with robust steganographic techniques to hide and communicate biometric data in mobile media objects like images, over open networks. More specifically, the aim is to embed binarised features extracted using discrete wavelet transforms and local binary patterns of face images as a secret message in an image. The need for such techniques can arise in law enforcement, forensics, counter terrorism, internet/mobile banking and border control. What differentiates this problem from normal information hiding techniques is the added requirement that there should be minimal effect on face recognition accuracy. We propose an LSB-Witness embedding technique in which the secret message is already present in the LSB plane but instead of changing the cover image LSB values, the second LSB plane will be changed to stand as a witness/informer to the receiver during message recovery. Although this approach may affect the stego quality, it is eliminating the weakness of traditional LSB schemes that is exploited by steganalysis techniques for LSB, such as PoV and RS steganalysis, to detect the existence of secrete message. Experimental results show that the proposed method is robust against PoV and RS attacks compared to other variants of LSB. We also discussed variants of this approach and determine capacity requirements for embedding face biometric feature vectors while maintain accuracy of face recognition.

  6. Constraint Embedding Technique for Multibody System Dynamics

    NASA Technical Reports Server (NTRS)

    Woo, Simon S.; Cheng, Michael K.

    2011-01-01

    Multibody dynamics play a critical role in simulation testbeds for space missions. There has been a considerable interest in the development of efficient computational algorithms for solving the dynamics of multibody systems. Mass matrix factorization and inversion techniques and the O(N) class of forward dynamics algorithms developed using a spatial operator algebra stand out as important breakthrough on this front. Techniques such as these provide the efficient algorithms and methods for the application and implementation of such multibody dynamics models. However, these methods are limited only to tree-topology multibody systems. Closed-chain topology systems require different techniques that are not as efficient or as broad as those for tree-topology systems. The closed-chain forward dynamics approach consists of treating the closed-chain topology as a tree-topology system subject to additional closure constraints. The resulting forward dynamics solution consists of: (a) ignoring the closure constraints and using the O(N) algorithm to solve for the free unconstrained accelerations for the system; (b) using the tree-topology solution to compute a correction force to enforce the closure constraints; and (c) correcting the unconstrained accelerations with correction accelerations resulting from the correction forces. This constraint-embedding technique shows how to use direct embedding to eliminate local closure-loops in the system and effectively convert the system back to a tree-topology system. At this point, standard tree-topology techniques can be brought to bear on the problem. The approach uses a spatial operator algebra approach to formulating the equations of motion. The operators are block-partitioned around the local body subgroups to convert them into aggregate bodies. Mass matrix operator factorization and inversion techniques are applied to the reformulated tree-topology system. Thus in essence, the new technique allows conversion of a system with

  7. Non-integer expansion embedding techniques for reversible image watermarking

    NASA Astrophysics Data System (ADS)

    Xiang, Shijun; Wang, Yi

    2015-12-01

    This work aims at reducing the embedding distortion of prediction-error expansion (PE)-based reversible watermarking. In the classical PE embedding method proposed by Thodi and Rodriguez, the predicted value is rounded to integer number for integer prediction-error expansion (IPE) embedding. The rounding operation makes a constraint on a predictor's performance. In this paper, we propose a non-integer PE (NIPE) embedding approach, which can proceed non-integer prediction errors for embedding data into an audio or image file by only expanding integer element of a prediction error while keeping its fractional element unchanged. The advantage of the NIPE embedding technique is that the NIPE technique can really bring a predictor into full play by estimating a sample/pixel in a noncausal way in a single pass since there is no rounding operation. A new noncausal image prediction method to estimate a pixel with four immediate pixels in a single pass is included in the proposed scheme. The proposed noncausal image predictor can provide better performance than Sachnev et al.'s noncausal double-set prediction method (where data prediction in two passes brings a distortion problem due to the fact that half of the pixels were predicted with the watermarked pixels). In comparison with existing several state-of-the-art works, experimental results have shown that the NIPE technique with the new noncausal prediction strategy can reduce the embedding distortion for the same embedding payload.

  8. Embedded coding technique - Principles and theoretical studies

    NASA Astrophysics Data System (ADS)

    Darnell, M.; Honary, B. K.; Zolghadr, F.

    1988-02-01

    In the paper the principles of embedded array codes, which employ a combination of forward error correction and detection (FEC/FED) for error control in an ARQ environment, are introduced. In this scheme a concatenated code with an inner code for error correction and an outer code for error detection is used. A retransmission of the erroneous information packets is requested if the outer code decoder detects the presence of any errors after the initial correction has been performed by the inner decoder. The theoretical expressions for the reliability and throughput efficiency of the system are derived. The performance of the system is analyzed and compared with that of a conventional array code. It is shown that the embedded scheme yields high reliability over a wide range of input bit error rates. A system of this type has many practical applications in situations where the transmission capacity of the communication channel varies with time; for example, on meteor-burst or HF(2-30 MHz) radio links.

  9. Microwave de-embedding techniques applied to acoustics.

    PubMed

    Jackson, Charles M

    2005-07-01

    This paper describes the use of the microwave techniques of time domain reflectometry (TDR) and de-embedding in an acoustical application. Two methods of calibrating the reflectometer are presented to evaluate the consistency of the method. Measured and modeled S-parameters of woodwind instruments are presented. The raw measured data is de-embedded to obtain an accurate measurement. The acoustic TDR setup is described. PMID:16212248

  10. Strain characterization of embedded aerospace smart materials using shearography

    NASA Astrophysics Data System (ADS)

    Anisimov, Andrei G.; Müller, Bernhard; Sinke, Jos; Groves, Roger M.

    2015-04-01

    The development of smart materials for embedding in aerospace composites provides enhanced functionality for future aircraft structures. Critical flight conditions like icing of the leading edges can affect the aircraft functionality and controllability. Hence, anti-icing and de-icing capabilities are used. In case of leading edges made of fibre metal laminates heater elements can be embedded between composite layers. However this local heating causes strains and stresses in the structure due to the different thermal expansion coefficients of the different laminated materials. In order to characterize the structural behaviour during thermal loading full-field strain and shape measurement can be used. In this research, a shearography instrument with three spatially-distributed shearing cameras is used to measure surface displacement gradients which give a quantitative estimation of the in- and out-of-plane surface strain components. For the experimental part, two GLARE (Glass Laminate Aluminum Reinforced Epoxy) specimens with six different embedded copper heater elements were manufactured: two copper mesh shapes (straight and S-shape), three connection techniques (soldered, spot welded and overlapped) and one straight heater element with delaminations. The surface strain behaviour of the specimens due to thermal loading was measured and analysed. The comparison of the connection techniques of heater element parts showed that the overlapped connection has the smallest effect on the surface strain distribution. Furthermore, the possibility of defect detection and defect depth characterisation close to the heater elements was also investigated.

  11. Site characterization techniques

    USGS Publications Warehouse

    U.S. Geological Survey

    1995-01-01

    Geoelectrical methods have been used since the 1920's to search for metallic ore deposits. During the last decade, traditional mining geophysical techniques have been adapted for environmental site characterization. Geoelectrical geophysics is now a well developed engineering specialty, with different methods to focus both on a range of targets and on depths below the surface. Most methods have also been adapted to borehole measurements.

  12. ElGamal cryptosystem with embedded compression-crypto technique

    NASA Astrophysics Data System (ADS)

    Mandangan, Arif; Yin, Lee Souk; Hung, Chang Ee; Hussin, Che Haziqah Che

    2014-12-01

    Key distribution problem in symmetric cryptography has been solved by the emergence of asymmetric cryptosystem. Due to its mathematical complexity, computation efficiency becomes a major problem in the real life application of asymmetric cryptosystem. This scenario encourage various researches regarding the enhancement of computation efficiency of asymmetric cryptosystems. ElGamal cryptosystem is one of the most established asymmetric cryptosystem. By using proper parameters, ElGamal cryptosystem is able to provide a good level of information security. On the other hand, Compression-Crypto technique is a technique used to reduce the number of plaintext to be encrypted from k∈ Z+, k > 2 plaintext become only 2 plaintext. Instead of encrypting k plaintext, we only need to encrypt these 2 plaintext. In this paper, we embed the Compression-Crypto technique into the ElGamal cryptosystem. To show that the embedded ElGamal cryptosystem works, we provide proofs on the decryption processes to recover the encrypted plaintext.

  13. Structural characterization of copolymer embedded magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Nedelcu, G. G.; Nastro, A.; Filippelli, L.; Cazacu, M.; Iacob, M.; Rossi, C. Oliviero; Popa, A.; Toloman, D.; Dobromir, M.; Iacomi, F.

    2015-10-01

    Small magnetic nanoparticles (Fe3O4) were synthesized by co-precipitation and coated by emulsion polymerization with poly(methyl methacrylate-co-acrylic acid) (PMMA-co-AAc) to create surface functional groups that can attach drug molecules and other biomolecules. The coated and uncoated magnetite nanoparticles were stored for two years in normal closed ships and than characterized by Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, vibrating sample magnetometry, and electron paramagnetic resonance spectroscopy. The solid phase transformation of magnetite to maghemite, as well as an increase in particle size were evidenced for the uncoated nanoparticles. The coated nanoparticles preserved their magnetite structure and magnetic properties. The influences of monomers and surfactant layers on interactions between the magnetic nanoparticles evidenced that the thickness of the polymer has a significant effect on magnetic properties.

  14. Techniques for embedding instrumentation in pressure vessel test articles

    NASA Astrophysics Data System (ADS)

    Cornelius, Michael

    2006-05-01

    Many interesting structural and thermal events occur in materials that are housed within a surrounding pressure vessel. In order to measure the environment during these events and explore their causes instrumentation must be installed on or in the material. Transducers can be selected that are small enough to be embedded within the test material but these instruments must interface with an external system in order to apply excitation voltages and output the desired data. The methods for installing the instrumentation and creating an interface are complicated when the material is located in a case or housing containing high pressures and hot gases. Installation techniques for overcoming some of these difficulties were developed while testing a series of small-scale solid propellant and hybrid rocket motors at Marshall Space Flight Center. These techniques have potential applications in other test articles where data are acquired from materials that require containment due to the severe environment encountered during the test process. This severe environment could include high pressure, hot gases, or ionized atmospheres. The development of these techniques, problems encountered, and the lessons learned from the ongoing testing process are summarized.

  15. Techniques for Embedding Instrumentation in Pressure Vessel Test Articles

    NASA Technical Reports Server (NTRS)

    Cornelius, Michael

    2006-01-01

    Many interesting structural and thermal events occur in materials that are housed within a surrounding pressure vessel. In order to measure the environment during these events and explore their causes instrumentation must be installed on or in the material. Transducers can be selected that are small enough to be embedded within the test material but these instruments must interface with an external system in order to apply excitation voltages and output the desired data. The methods for installing the instrumentation and creating an interface are complicated when the material is located in a case or housing containing high pressures and hot gases. Installation techniques for overcoming some of these difficulties were developed while testing a series of small-scale solid propellant and hybrid rocket motors at Marshall Space Flight Center. These techniques have potential applications in other test articles where data are acquired from materials that require containment due to the severe environment encountered during the test process. This severe environment could include high pressure, hot gases, or ionized atmospheres. The development of these techniques, problems encountered, and the lessons learned from the ongoing testing process are summarized.

  16. Techniques for Characterizing Microwave Printed Antennas

    NASA Technical Reports Server (NTRS)

    Simons, Rainee; Lee, Richard Q.

    2003-01-01

    The combination of a de-embedding technique and a direct on-substrate measurement technique has been devised to enable measurement of the electrical characteristics (impedances, scattering parameters, and gains) of microwave printed antennas that may be formed integrally with feed networks that include slot lines, coplanar striplines, and/or coplanar waveguides. The combination of techniques eliminates the need for custom test fixtures, including transitions between (1) coaxial or waveguide feed lines in typical test equipment and (2) the planar waveguide structures of the printed circuits under test. The combination of techniques can be expected to be especially useful for rapid, inexpensive, and accurate characterization of antennas for miniature wireless communication units that operate at frequencies from a few to tens of gigahertz.

  17. Machine learning techniques for energy optimization in mobile embedded systems

    NASA Astrophysics Data System (ADS)

    Donohoo, Brad Kyoshi

    Mobile smartphones and other portable battery operated embedded systems (PDAs, tablets) are pervasive computing devices that have emerged in recent years as essential instruments for communication, business, and social interactions. While performance, capabilities, and design are all important considerations when purchasing a mobile device, a long battery lifetime is one of the most desirable attributes. Battery technology and capacity has improved over the years, but it still cannot keep pace with the power consumption demands of today's mobile devices. This key limiter has led to a strong research emphasis on extending battery lifetime by minimizing energy consumption, primarily using software optimizations. This thesis presents two strategies that attempt to optimize mobile device energy consumption with negligible impact on user perception and quality of service (QoS). The first strategy proposes an application and user interaction aware middleware framework that takes advantage of user idle time between interaction events of the foreground application to optimize CPU and screen backlight energy consumption. The framework dynamically classifies mobile device applications based on their received interaction patterns, then invokes a number of different power management algorithms to adjust processor frequency and screen backlight levels accordingly. The second strategy proposes the usage of machine learning techniques to learn a user's mobile device usage pattern pertaining to spatiotemporal and device contexts, and then predict energy-optimal data and location interface configurations. By learning where and when a mobile device user uses certain power-hungry interfaces (3G, WiFi, and GPS), the techniques, which include variants of linear discriminant analysis, linear logistic regression, non-linear logistic regression, and k-nearest neighbor, are able to dynamically turn off unnecessary interfaces at runtime in order to save energy.

  18. Characterizing and Diminishing Autofluorescence in Formalin-fixed Paraffin-embedded Human Respiratory Tissue.

    PubMed

    Davis, A Sally; Richter, Anke; Becker, Steven; Moyer, Jenna E; Sandouk, Aline; Skinner, Jeff; Taubenberger, Jeffery K

    2014-04-10

    Tissue autofluorescence frequently hampers visualization of immunofluorescent markers in formalin-fixed paraffin-embedded respiratory tissues. We assessed nine treatments reported to have efficacy in reducing autofluorescence in other tissue types. The three most efficacious were Eriochrome black T, Sudan black B and sodium borohydride, as measured using white light laser confocal Λ(2) (multi-lambda) analysis. We also assessed the impact of steam antigen retrieval and serum application on human tracheal tissue autofluorescence. Functionally fitting this Λ(2) data to 2-dimensional Gaussian surfaces revealed that steam antigen retrieval and serum application contribute minimally to autofluorescence and that the three treatments are disparately efficacious. Together, these studies provide a set of guidelines for diminishing autofluorescence in formalin-fixed paraffin-embedded human respiratory tissue. Additionally, these characterization techniques are transferable to similar questions in other tissue types, as demonstrated on frozen human liver tissue and paraffin-embedded mouse lung tissue fixed in different fixatives. PMID:24722432

  19. Embedded wavelet packet transform technique for texture compression

    NASA Astrophysics Data System (ADS)

    Li, Jin; Cheng, Po-Yuen; Kuo, C.-C. Jay

    1995-09-01

    A highly efficient texture compression scheme is proposed in this research. With this scheme, energy compaction of texture images is first achieved by the wavelet packet transform, and an embedding approach is then adopted for the coding of the wavelet packet transform coefficients. By comparing the proposed algorithm with the JPEG standard, FBI wavelet/scalar quantization standard and the EZW scheme with extensive experimental results, we observe a significant improvement in the rate-distortion performance and visual quality.

  20. Single Cell Electrical Characterization Techniques

    PubMed Central

    Mansor, Muhammad Asraf; Ahmad, Mohd Ridzuan

    2015-01-01

    Electrical properties of living cells have been proven to play significant roles in understanding of various biological activities including disease progression both at the cellular and molecular levels. Since two decades ago, many researchers have developed tools to analyze the cell’s electrical states especially in single cell analysis (SCA). In depth analysis and more fully described activities of cell differentiation and cancer can only be accomplished with single cell analysis. This growing interest was supported by the emergence of various microfluidic techniques to fulfill high precisions screening, reduced equipment cost and low analysis time for characterization of the single cell’s electrical properties, as compared to classical bulky technique. This paper presents a historical review of single cell electrical properties analysis development from classical techniques to recent advances in microfluidic techniques. Technical details of the different microfluidic techniques are highlighted, and the advantages and limitations of various microfluidic devices are discussed. PMID:26053399

  1. Synthesis and characterization of nano ZnO, nano Ag/ZnO composite & nano-particles embedded polymers

    NASA Astrophysics Data System (ADS)

    Are, Thilak Reddy

    Zinc oxide and silver/zinc oxide nano particles were synthesized by a simple precipitation method in the presence of polyvinylpyrrolidone (PVP). The presence of polyvinylpyrrolidone prevents agglomeration and allows the formation of nano sized particles. Characterization of synthesized nano particles were carried out using X-ray powder diffraction, differential scanning calorimetry, scanning electron microscopy, and the average sizes were determined by zeta seizer. The X-ray diffraction shows that the prepared particles were poorly crystalline. The DSC results show that the prepared particles are highly stable and no phase changes were observed when heated from room temperature to 500°C. Scanning electron microscopic observation shows that the particles are uniformly distributed with similar shape. Zeta seizer results show that the prepared particles are nano-particles with average size of about 100 nm. The prepared Zinc oxide nano particles were embedded into the polycaprolactone (PCL) polymer to study the effect of embedding zinc oxide nanoparticle on PCL crystallinity and mechanical properties. ZnO nano particles were successfully embedded into the polymer using in-situ and non-in-situ embedding processes. Characterization of PCL embedded with ZnO nanoparticles was performed by X-ray diffraction technique and scanning electron microscope. Crystallinity studies were done by using differential scanning calorimetry and the results show that the polymer embedded using an in situ process showed a decrease in crystallinity compared to the polymer embedded using a non-insitu process.

  2. Surface Characterization Techniques: An Overview

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    2002-01-01

    To understand the benefits that surface modifications provide, and ultimately to devise better ones, it is necessary to study the physical, mechanical, and chemical changes they cause. This chapter surveys classical and leading-edge developments in surface structure and property characterization methodologies. The primary emphases are on the use of these techniques as they relate to surface modifications, thin films and coatings, and tribological engineering surfaces and on the implications rather than the instrumentation.

  3. Expansion Techniques of Embedding Audio Watermark Data Rate for Constructing Ubiquitous Acoustic Spaces

    NASA Astrophysics Data System (ADS)

    Modegi, Toshio

    We are proposing “Ubiquitous Acoustic Spaces”, where each sound source can emit some address information with audio signals and make us automatically access to its related cyber space, using handheld devices such as cellphones. In order to realize this concept, we have considered three types of extraction methods, which were an acoustic modulation, an audio fingerprint, and an audio watermark technique. Then we have proposed a novel audio watermarking technique, which enables contactless asynchronous detection of embedded audio watermarks through speaker and microphone devices. However its embedding data rate was around 10 [bps], which was not sufficient for embedding generally used URL address texts. Therefore, we have extended the embedding frequency range and proposed a duplicated embedding algorithm, which uses both previously proposed frequency division method and temporal division method together. By these improvements, possible embedding data rate could be extended to 61.5 [bps], and we could extract watermarks through public telephone networks, even from a cell phone sound source. In this paper, we describe abstracts of our improved watermark embedding and extracting algorithms, and experimental results of watermark extraction precision on several audio signal capturing conditions.

  4. Characterization of heavy metal particles embedded in tire dust.

    PubMed

    Adachi, Kouji; Tainosho, Yoshiaki

    2004-10-01

    Tire dust is a significant pollutant, especially as a source of zinc in the urban environment. This study characterizes the morphology and chemical composition of heavy metal particles embedded in tire dust and traffic-related materials (brake dust, yellow paint, and tire tread) as measured by a field emission scanning electron microscope equipped with an energy dispersive X-ray spectrometer (FESEM/EDX). In 60 samples of tire dust, we detected 2288 heavy metal particles, which we classified into four groups using cluster analysis according to the following typical elements: cluster 1: Fe, cluster 2: Cr/Pb, cluster 3: multiple elements (Ti, Cr, Fe, Cu, Zn, Sr, Y, Zr, Sn, Sb, Ba, La, Ce, Pb), cluster 4: ZnO. According to their morphologies and chemical compositions, the possible sources of each cluster were as follows: (1) brake dust (particles rich in Fe and with trace Cu, Sb, and Ba), (2) yellow paint (CrPbO(4) particles), (3) brake dust (particulate Ti, Fe, Cu, Sb, Zr, and Ba) and heavy minerals (Y, Zr, La, and Ce), (4) tire tread (zinc oxide). When the chemical composition of tire dust was compared to that of tire tread, the tire dust was found to have greater concentrations of heavy metal elements as well as mineral or asphalt pavement material characterized by Al, Si, and Ca. We conclude that tire dust consists not only of the debris from tire wear but also of assimilated heavy metal particles emitted from road traffic materials such as brake lining and road paint. PMID:15337346

  5. Characterization techniques for incorporating backgrounds into DIRSIG

    NASA Astrophysics Data System (ADS)

    Brown, Scott D.; Schott, John R.

    2000-07-01

    The appearance of operation hyperspectral imaging spectrometers in both solar and thermal regions has lead to the development of a variety of spectral detection algorithms. The development and testing of these algorithms requires well characterized field collection campaigns that can be time and cost prohibitive. Radiometrically robust synthetic image generation (SIG) environments that can generate appropriate images under a variety of atmospheric conditions and with a variety of sensors offers an excellent supplement to reduce the scope of the expensive field collections. In addition, SIG image products provide the algorithm developer with per-pixel truth, allowing for improved characterization of the algorithm performance. To meet the needs of the algorithm development community, the image modeling community needs to supply synthetic image products that contain all the spatial and spectral variability present in real world scenes, and that provide the large area coverage typically acquired with actual sensors. This places a heavy burden on synthetic scene builders to construct well characterized scenes that span large areas. Several SIG models have demonstrated the ability to accurately model targets (vehicles, buildings, etc.) Using well constructed target geometry (from CAD packages) and robust thermal and radiometry models. However, background objects (vegetation, infrastructure, etc.) dominate the percentage of real world scene pixels and utilizing target building techniques is time and resource prohibitive. This paper discusses new methods that have been integrated into the Digital Imaging and Remote Sensing Image Generation (DIRSIG) model to characterize backgrounds. The new suite of scene construct types allows the user to incorporate both terrain and surface properties to obtain wide area coverage. The terrain can be incorporated using a triangular irregular network (TIN) derived from elevation data or digital elevation model (DEM) data from actual

  6. A damage identification technique based on embedded sensitivity analysis and optimization processes

    NASA Astrophysics Data System (ADS)

    Yang, Chulho; Adams, Douglas E.

    2014-07-01

    A vibration based structural damage identification method, using embedded sensitivity functions and optimization algorithms, is discussed in this work. The embedded sensitivity technique requires only measured or calculated frequency response functions to obtain the sensitivity of system responses to each component parameter. Therefore, this sensitivity analysis technique can be effectively used for the damage identification process. Optimization techniques are used to minimize the difference between the measured frequency response functions of the damaged structure and those calculated from the baseline system using embedded sensitivity functions. The amount of damage can be quantified directly in engineering units as changes in stiffness, damping, or mass. Various factors in the optimization process and structural dynamics are studied to enhance the performance and robustness of the damage identification process. This study shows that the proposed technique can improve the accuracy of damage identification with less than 2 percent error of estimation.

  7. A practical approach for the correction of iatrogenic penile skin loss in children: Scrotal embedding technique

    PubMed Central

    Ziylan, Orhan; Acar, Ömer; Özden, Burcu Celet; Tefik, Tzevat; Dönmez, M. İrfan; Oktar, Tayfun

    2015-01-01

    The aim of this particular study is to determine the efficacy of scrotal embedding technique in children with overly deficient penile shaft skin, which takes advantage of the rich vascular supply of the scrotal layers and provides adequate tissue coverage. We give the operative and clinical details of two consecutive cases for which we preferred scrotal embedding technique to replace deficient penile skin. The mean operative time for the first and second stages was 72.5 and 52.5 min, respectively. Intraoperative and postoperative courses and convalescences were uneventful. The patients were hospitalized for a mean duration of 2 days. After a mean follow-up of 29 months, cosmetic and functional results were satisfactory. Scrotal embedding technique should be considered as a feasible surgical alternative while reconstructing the penile shaft in iatrogenic cases with overly deficient shaft skin. PMID:26623155

  8. Dimensional characterization of anesthesia dynamic in reconstructed embedding space.

    PubMed

    Gifani, P; Rabiee, H R; Hashemi, M; Ghanbari, M

    2007-01-01

    The depth of anesthesia quantification has been one of the most research interests in the field of EEG signal processing and nonlinear dynamical analysis has emerged as a novel method for the study of complex systems in the past few decades. In this investigation we use the concept of nonlinear time series analysis techniques to reconstruct the attractor of anesthesia from EEG signal which have been obtained from different hypnotic states during surgery to give a characterization of the dimensional complexity of EEG by Correlation Dimension estimation. The dimension of the anesthesia strange attractor can be thought of as a measure of the degrees of freedom or the ;complexity' of the dynamics at different hypnotic levels. The results imply that for awaked state the correlation dimension is high, On the other hand, for light, moderate and deep hypnotic states these values decrease respectively; which means for anesthetized situation we expect lower correlation dimension. PMID:18003510

  9. Preparation and nonlinear characterization of zinc selenide nanoparticles embedded in polymer matrix

    NASA Astrophysics Data System (ADS)

    Sharma, Mamta; Tripathi, S. K.

    2012-09-01

    Nanocomposites of ZnSe nanoparticles embedded in polyvinyl alcohol (PVA) matrix have been prepared by in-situ synthesis. ZnSe/PVA nanocomposites are characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and UV/Vis spectra. The nanocomposite structure is confirmed by the blue-shift of the absorption edge. The nonlinear refractive index and two-photon absorption (TPA) coefficient are measured by the Z-scan technique using low power CW He-Ne laser light. The results show that the ZnSe nanocomposite films show large optical nonlinearity and the magnitude of the third-order nonlinear susceptibility χ(3) is calculated to be 2.62×13-11 m2/V2.

  10. Synthesis and characterization of magnetic nanoparticles embedded in polyacrylonitrile nanofibers

    NASA Astrophysics Data System (ADS)

    Munteanu, Daniel; Ion, Rodica-Mariana; Cocina, George-Costel

    2010-11-01

    Nanomedicine is defined as the monitoring, repair, construction, and control of human biological systems at the molecular level using engineered nanodevices and nanostructures. Polyacrylonitrile (PAN) solution containing the iron oxide precursor iron (III) was electrospun and thermally treated to produce electrically conducting, magnetic carbon nanofiber mats with hierarchical pore structures. This paper discusses the synthesis of magnetite (Fe3O4) nanoparticles with mean crystallite size of 10 nm with polyacrylonitrile (PAN) as the protecting agent, creating nanofiber. The morphology and material properties of the resulting multifunctional nanofiber including the surface area were examined using various characterization techniques. Optical microscopy images show that uniform fibers were produced with a fiber diameter of ~600 nm, and this uniform fiber morphology is maintained after graphitization with a fiber diameter of ~330 nm. X-ray diffraction (XRD) studies reveal the size of Fe3O4 crystals. A combination of XRD and electron microscopy experiments reveals the formation of pores with graphitic nanoparticles in the walls as well as the formation of magnetite nanoparticles distributed throughout the fibers.

  11. Use of Raman Spectroscopy in Characterizing Formalin-Fixed, Paraffin-Embedded Breast Tumor Samples (abstract)

    NASA Astrophysics Data System (ADS)

    Downey, Frances; Cade, Nicholas; Cook, Richard; Springall, Robert; Gillet, Cheryl; Richards, David; Festy, Frederic

    2009-04-01

    Formalin-fixed, paraffin-embedded (FFPE) sections of breast tissue are used by pathologists to correctly type and grade the primary tumor and to assess the extent of a patient's disease. The cut sections represent a reproducible likeness of the morphology of the tissue when viewed through a microscope, although the fixation technique creates some artifacts. What is not known is how the sections differ chemically from how the tumor would look or behave within the breast. Raman spectroscopy is, like many other optical techniques, fast, noninvasive, and generally inexpensive. The advantage Raman has over other techniques is its powerful ability to identify specific chemicals, molecules, and bonds within a sample. Using Raman spectroscopy the chemicals present in both fresh tissue and FFPE sections can be identified and compared, allowing any differences between them to be identified. This information may be useful to the pathologist as an aid to further treatment regimes or novel molecular techniques, and as an aid to patient management. If these sections are found to be chemically similar to fresh tissue, they could be used to further characterize breast tumors, particularly rare tumors, using Raman spectroscopy.

  12. Graph Embedding Techniques for Bounding Condition Numbers of Incomplete Factor Preconditioning

    NASA Technical Reports Server (NTRS)

    Guattery, Stephen

    1997-01-01

    We extend graph embedding techniques for bounding the spectral condition number of preconditioned systems involving symmetric, irreducibly diagonally dominant M-matrices to systems where the preconditioner is not diagonally dominant. In particular, this allows us to bound the spectral condition number when the preconditioner is based on an incomplete factorization. We provide a review of previous techniques, describe our extension, and give examples both of a bound for a model problem, and of ways in which our techniques give intuitive way of looking at incomplete factor preconditioners.

  13. Efficient simulation of blood flow past complex endovascular devices using an adaptive embedding technique.

    PubMed

    Cebral, Juan R; Löhner, Rainald

    2005-04-01

    The simulation of blood flow past endovascular devices such as coils and stents is a challenging problem due to the complex geometry of the devices. Traditional unstructured grid computational fluid dynamics relies on the generation of finite element grids that conform to the boundary of the computational domain. However, the generation of such grids for patient-specific modeling of cerebral aneurysm treatment with coils or stents is extremely difficult and time consuming. This paper describes the application of an adaptive grid embedding technique previously developed for complex fluid structure interaction problems to the simulation of endovascular devices. A hybrid approach is used: the vessel walls are treated with body conforming grids and the endovascular devices with an adaptive mesh embedding technique. This methodology fits naturally in the framework of image-based computational fluid dynamics and opens the door for exploration of different therapeutic options and personalization of endovascular procedures. PMID:15822805

  14. MetricMap: an embedding technique for processing distance-based queries in metric spaces.

    PubMed

    Wang, Jason T L; Wang, Xiong; Shasha, Dennis; Zhang, Kaizhong

    2005-10-01

    In this paper, we present an embedding technique, called MetricMap, which is capable of estimating distances in a pseudometric space. Given a database of objects and a distance function for the objects, which is a pseudometric, we map the objects to vectors in a pseudo-Euclidean space with a reasonably low dimension while preserving the distance between two objects approximately. Such an embedding technique can be used as an approximate oracle to process a broad class of distance-based queries. It is also adaptable to data mining applications such as data clustering and classification. We present the theory underlying MetricMap and conduct experiments to compare MetricMap with other methods including MVP-tree and M-tree in processing the distance-based queries. Experimental results on both protein and RNA data show the good performance and the superiority of MetricMap over the other methods. PMID:16240772

  15. Microwave oven-based technique for immunofluorescent staining of paraffin-embedded tissues

    PubMed Central

    Buggs, Colleen

    2011-01-01

    Immunohistochemical analysis of formalin-fixed paraffin-embedded tissues can be challenging due to potential modifications of protein structure by exposure to formalin. Heat-induced antigen retrieval techniques can reverse reactions between formalin and proteins that block antibody recognition. Interactions between antibodies and antigens are further enhanced by microwave irradiation, which has simplified immunohistochemical staining protocols. In this report, we modify a technique for antigen retrieval and immunofluorescent staining of formalin-fixed paraffin-embedded tissues by showing that it works well with several antibodies and buffers. This microwave-assisted method for antigen retrieval and immunofluorescent staining eliminates the need for blocking reagents and extended washes, which greatly simplifies the protocol allowing one to complete the analysis in less than 3 h. PMID:17653827

  16. Plant cell wall characterization using scanning probe microscopy techniques

    PubMed Central

    Yarbrough, John M; Himmel, Michael E; Ding, Shi-You

    2009-01-01

    Lignocellulosic biomass is today considered a promising renewable resource for bioenergy production. A combined chemical and biological process is currently under consideration for the conversion of polysaccharides from plant cell wall materials, mainly cellulose and hemicelluloses, to simple sugars that can be fermented to biofuels. Native plant cellulose forms nanometer-scale microfibrils that are embedded in a polymeric network of hemicelluloses, pectins, and lignins; this explains, in part, the recalcitrance of biomass to deconstruction. The chemical and structural characteristics of these plant cell wall constituents remain largely unknown today. Scanning probe microscopy techniques, particularly atomic force microscopy and its application in characterizing plant cell wall structure, are reviewed here. We also further discuss future developments based on scanning probe microscopy techniques that combine linear and nonlinear optical techniques to characterize plant cell wall nanometer-scale structures, specifically apertureless near-field scanning optical microscopy and coherent anti-Stokes Raman scattering microscopy. PMID:19703302

  17. Non-destructive elemental quantification of polymer-embedded thin films using laboratory based X-ray techniques

    NASA Astrophysics Data System (ADS)

    Cordes, Nikolaus L.; Havrilla, George J.; Usov, Igor O.; Obrey, Kimberly A.; Patterson, Brian M.

    2014-11-01

    Thin coatings are important for a variety of industries including energy (e.g., solar cells, batteries), consumer electronics (e.g., LCD displays, computer chips), and medical devices (e.g., implants). These coatings are typically highly uniform layers with thicknesses ranging from a monolayer up to several micrometers. Characterizing these highly uniform coatings for their thickness, elemental composition, and uniformity are all paramount, but obtaining these measurements can be more difficult when the layers are subsurface and must be interrogated non-destructively. The coupling of confocal micro-X-ray fluorescence (confocal MXRF) and nano-scale X-ray computed tomography (nano-CT) together can make these measurements while meeting these sensitivity and resolution specifications necessary for characterizing thin films. Elemental composition, atomic percent, placement, and uniformity can be measured in three dimensions with this integrated approach. Confocal MXRF uses a pair of polycapillary optics to focus and collect X-rays from a material from a 3D spatially restricted confocal volume. Because of the spatial definition, individual layers (of differing composition) can be characterized based upon the elementally characteristic X-ray fluorescence collected for each element. Nano-scale X-ray computed tomography, in comparison, can image the layers at very high resolution (down to 50 nm) to precisely measure the embedded layer thickness. These two techniques must be used together if both the thickness and atomic density of a layer are unknown. This manuscript will demonstrate that it is possible to measure both the atomic percent of an embedded thin film layer and confirm its manufacturing quality. As a proof of principle, a 1.5 atomic percent, 2 μm-thick Ge layer embedded within polymer capsules, used for laser plasma experiments at the Omega Laser Facility and National Ignition Facility, are measured.

  18. Ambient air contamination: Characterization and detection techniques

    NASA Technical Reports Server (NTRS)

    Nulton, C. P.; Silvus, H. S.

    1985-01-01

    Techniques to characterize and detect sources of ambient air contamination are described. Chemical techniques to identify indoor contaminants are outlined, they include gas chromatography, or colorimetric detection. Organics generated from indoor materials at ambient conditions and upon combustion are characterized. Piezoelectric quartz crystals are used as precision frequency determining elements in electronic oscillators.

  19. Signal processing techniques for damage detection with piezoelectric wafer active sensors and embedded ultrasonic structural radar

    NASA Astrophysics Data System (ADS)

    Yu, Lingyu; Bao, Jingjing; Giurgiutiu, Victor

    2004-07-01

    Embedded ultrasonic structural radar (EUSR) algorithm is developed for using piezoelectric wafer active sensor (PWAS) array to detect defects within a large area of a thin-plate specimen. Signal processing techniques are used to extract the time of flight of the wave packages, and thereby to determine the location of the defects with the EUSR algorithm. In our research, the transient tone-burst wave propagation signals are generated and collected by the embedded PWAS. Then, with signal processing, the frequency contents of the signals and the time of flight of individual frequencies are determined. This paper starts with an introduction of embedded ultrasonic structural radar algorithm. Then we will describe the signal processing methods used to extract the time of flight of the wave packages. The signal processing methods being used include the wavelet denoising, the cross correlation, and Hilbert transform. Though hardware device can provide averaging function to eliminate the noise coming from the signal collection process, wavelet denoising is included to ensure better signal quality for the application in real severe environment. For better recognition of time of flight, cross correlation method is used. Hilbert transform is applied to the signals after cross correlation in order to extract the envelope of the signals. Signal processing and EUSR are both implemented by developing a graphical user-friendly interface program in LabView. We conclude with a description of our vision for applying EUSR signal analysis to structural health monitoring and embedded nondestructive evaluation. To this end, we envisage an automatic damage detection application utilizing embedded PWAS, EUSR, and advanced signal processing.

  20. Size-dependent characterization of embedded Ge nanocrystals: Structural and thermal properties

    NASA Astrophysics Data System (ADS)

    Araujo, L. L.; Giulian, R.; Sprouster, D. J.; Schnohr, C. S.; Llewellyn, D. J.; Kluth, P.; Cookson, D. J.; Foran, G. J.; Ridgway, M. C.

    2008-09-01

    A combination of conventional and synchrotron-based techniques has been used to characterize the size-dependent structural and thermal properties of Ge nanocrystals (NCs) embedded in a silica (a-SiO2) matrix. Ge NC size distributions with four different diameters ranging from 4.0 to 9.0 nm were produced by ion implantation and thermal annealing as characterized with small-angle x-ray scattering and transmission electron microscopy. The NCs were well represented by the superposition of bulklike crystalline and amorphous environments, suggesting the formation of an amorphous layer separating the crystalline NC core and the a-SiO2 matrix. The amorphous fraction was quantified with x-ray-absorption near-edge spectroscopy and increased as the NC diameter decreased, consistent with the increase in surface-to-volume ratio. The structural parameters of the first three nearest-neighbor shells were determined with extended x-ray-absorption fine-structure (EXAFS) spectroscopy and evolved linearly with inverse NC diameter. Specifically, increases in total disorder, interatomic distance, and the asymmetry in the distribution of distances were observed as the NC size decreased, demonstrating that finite-size effects govern the structural properties of embedded Ge NCs. Temperature-dependent EXAFS measurements in the range of 15-300 K were employed to probe the mean vibrational frequency and the variation of the interatomic distance distribution (mean value, variance, and asymmetry) with temperature for all NC distributions. A clear trend of increased stiffness (higher vibrational frequency) and decreased thermal expansion with decreasing NC size was evident, confirming the close relationship between the variation of structural and thermal/vibrational properties with size for embedded Ge NCs. The increase in surface-to-volume ratio and the presence of an amorphous Ge layer separating the matrix and crystalline NC core are identified as the main factors responsible for the observed

  1. Immunostaining of keratin and vimentin in epidermis: comparison of different post-embedding immunogold techniques for electron microscopy.

    PubMed

    Mahrle, G; Schulze, H J; Kuhn, A; Wevers, A

    1989-06-01

    The present study compares different post-embedding staining methods, including conventional and low-temperature embedding techniques, for demonstration of the keratin and vimentin cytoskeleton of epidermal cells, applying commercially available polyclonal and monoclonal antibodies. Immunogold staining (5-nm particles) was performed on the following material: (a) osmium-fixed and Durcupan-embedded material, etched with various solutions; (b) aldehyde-fixed material embedded in Lowicryl K4M at 4 degrees C and -35 degrees C; (c) aldehyde-fixed material embedded in Lowicryl K11M at -60 degrees C with and without cryoprotection with glycerol. In conventionally embedded material we failed to demonstrate intermediate filaments, whereas they were stained after low-temperature embedding with Lowicryl, i.e., K4M 4 degrees C, K4M -35 degrees C, and K11M -60 degrees C. The keratin and vimentin cytoskeleton reacted exclusively with polyclonal antibodies. The best results for antigenicity as well as structural preservation were achieved by post-embedding staining of K4M -35 degrees C-embedded material. Antibodies to keratin stained the cytoskeleton in keratinocytes of all epidermal layers. Filaments were decorated in a linear alignment. Antibodies to vimentin stained the cytoskeleton of Langerhans cells and melanocytes. In these cells a linear distribution pattern of the reaction product along the filaments and an extrafilamentous cluster formation were observed, indicating staining of vimentin and a vimentin-associated protein. PMID:2470809

  2. Characterization techniques for surface-micromachined devices

    SciTech Connect

    Eaton, W.P.; Smith, N.F.; Irwin, L.; Tanner, D.M.

    1998-08-01

    Using a microengine as the primary test vehicle, the authors have examined several aspects of characterization. Parametric measurements provide fabrication process information. Drive signal optimization is necessary for increased microengine performance. Finally, electrical characterization of resonant frequency and quality factor can be more accurate than visual techniques.

  3. Characterization of embedded fiber optic strain sensors into metallic structures via ultrasonic additive manufacturing

    NASA Astrophysics Data System (ADS)

    Schomer, John J.; Hehr, Adam J.; Dapino, Marcelo J.

    2016-04-01

    Fiber Bragg Grating (FBG) sensors measure deviation in a reflected wavelength of light to detect in-situ strain. These sensors are immune to electromagnetic interference, and the inclusion of multiple FBGs on the same fiber allows for a seamlessly integrated sensing network. FBGs are attractive for embedded sensing in aerospace applications due to their small noninvasive size and prospect of constant, real-time nondestructive evaluation. In this study, FBG sensors are embedded in aluminum 6061 via ultrasonic additive manufacturing (UAM), a rapid prototyping process that uses high power ultrasonic vibrations to weld similar and dissimilar metal foils together. UAM was chosen due to the desire to embed FBG sensors at low temperatures, a requirement that excludes other additive processes such as selective laser sintering or fusion deposition modeling. In this paper, the embedded FBGs are characterized in terms of birefringence losses, post embedding strain shifts, consolidation quality, and strain sensing performance. Sensors embedded into an ASTM test piece are compared against an exterior surface mounted foil strain gage at both room and elevated temperatures using cyclic tensile tests.

  4. Subsurface synthesis and characterization of Ag nanoparticles embedded in MgO.

    PubMed

    Vilayurganapathy, S; Devaraj, A; Colby, R; Pandey, A; Varga, T; Shutthanandan, V; Manandhar, S; El-Khoury, P Z; Kayani, Asghar; Hess, W P; Thevuthasan, S

    2013-03-01

    Metal nanoparticles exhibit a localized surface plasmon resonance (LSPR) which is very sensitive to the size and shape of the nanoparticle and the surrounding dielectric medium. The coupling between the electromagnetic radiation and the localized surface plasmon in metallic nanoparticles results in a sizable enhancement of the incident fields, making them possible candidates for plasmonic applications. In particular, partially exposed metallic nanoparticles distributed in a dielectric matrix can provide prime locations for LSPR spectroscopy and sensing. We report the synthesis and characterization of a plasmonic substrate consisting of Ag nanoparticles partially buried in MgO. Ag nanoparticles of different shapes and size distributions were synthesized below the surface of MgO by implanting 200 keV Ag(+) ions followed by annealing at 1000 °C for 10 and 30 h. A detailed optical and structural characterization was carried out to understand the evolution of the Ag nanoparticle and size distribution inside the MgO matrix. Micro x-ray diffraction (Micro-XRD) was employed to investigate the structural properties and estimate the crystallite size. The nanoparticles evolved from a spherical to a faceted morphology with annealing time, assuming an octahedral shape truncated at the (001) planes, as visualized from aberration-corrected transmission electron microscopy (TEM) images. The nanoparticles embedded in MgO were shown to be pure metallic Ag using atom probe tomography (APT). The nanoparticles were partially exposed to the surface by employing plasma etch techniques to remove the overlaying MgO. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed to study the surface morphology and obtain a height distribution for the partially exposed nanoparticles. PMID:23403363

  5. Subsurface synthesis and characterization of Ag nanoparticles embedded in MgO

    NASA Astrophysics Data System (ADS)

    Vilayurganapathy, S.; Devaraj, A.; Colby, R.; Pandey, A.; Varga, T.; Shutthanandan, V.; Manandhar, S.; El-Khoury, P. Z.; Kayani, Asghar; Hess, W. P.; Thevuthasan, S.

    2013-03-01

    Metal nanoparticles exhibit a localized surface plasmon resonance (LSPR) which is very sensitive to the size and shape of the nanoparticle and the surrounding dielectric medium. The coupling between the electromagnetic radiation and the localized surface plasmon in metallic nanoparticles results in a sizable enhancement of the incident fields, making them possible candidates for plasmonic applications. In particular, partially exposed metallic nanoparticles distributed in a dielectric matrix can provide prime locations for LSPR spectroscopy and sensing. We report the synthesis and characterization of a plasmonic substrate consisting of Ag nanoparticles partially buried in MgO. Ag nanoparticles of different shapes and size distributions were synthesized below the surface of MgO by implanting 200 keV Ag+ ions followed by annealing at 1000 °C for 10 and 30 h. A detailed optical and structural characterization was carried out to understand the evolution of the Ag nanoparticle and size distribution inside the MgO matrix. Micro x-ray diffraction (Micro-XRD) was employed to investigate the structural properties and estimate the crystallite size. The nanoparticles evolved from a spherical to a faceted morphology with annealing time, assuming an octahedral shape truncated at the (001) planes, as visualized from aberration-corrected transmission electron microscopy (TEM) images. The nanoparticles embedded in MgO were shown to be pure metallic Ag using atom probe tomography (APT). The nanoparticles were partially exposed to the surface by employing plasma etch techniques to remove the overlaying MgO. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed to study the surface morphology and obtain a height distribution for the partially exposed nanoparticles.

  6. Preparation and characterization of Ag nanoparticle-embedded blank and ligand-anchored silica gels.

    PubMed

    Im, Hee-Jung; Lee, Byung Cheol; Yeon, Jei-Won

    2013-11-01

    Ag nanoparticles, used for halogen (especially iodine) adsorption and an evaluation of halogen behavior, were embedded in synthesized inorganic-organic hybrid gels. In particular, an irradiation method using an electron beam plays a part in introducing Ag nanoparticles to the organofunctionalized silica gels from AgNO3 solutions in a simple way at atmospheric pressure and room temperature. For preparation of the Ag nanoparticle-embedded inorganic-organic hybrid gels, ligands of ethylenediamine (NH2CH2CH2NH-, TMSen) and mercapto (HS-) functionalized three-dimensional porous SiO2 sol-gels were first synthesized through hydrolysis and condensation reactions, and Ag nanoparticles were then embedded into the ethylenediamine- and mercapto-anchored silica gels each, through electron-beam irradiation. The addition of ligands yielded larger average pore sizes than the absence of any ligand. Moreover, the ethylenediamine ligand led to looser structures and better access of the Ag nanoparticles to the ethylenediamine-anchored gel. As a result, more Ag nanoparticles were introduced into the ethylenediamine-anchored gel. The preparation and characterization of Ag nanoparticle-embedded blank and ligand-anchored silica gels are discussed in detail. PMID:24245307

  7. Optical Measurement Technique for Space Column Characterization

    NASA Technical Reports Server (NTRS)

    Barrows, Danny A.; Watson, Judith J.; Burner, Alpheus W.; Phelps, James E.

    2004-01-01

    A simple optical technique for the structural characterization of lightweight space columns is presented. The technique is useful for determining the coefficient of thermal expansion during cool down as well as the induced strain during tension and compression testing. The technique is based upon object-to-image plane scaling and does not require any photogrammetric calibrations or computations. Examples of the measurement of the coefficient of thermal expansion are presented for several lightweight space columns. Examples of strain measured during tension and compression testing are presented along with comparisons to results obtained with Linear Variable Differential Transformer (LVDT) position transducers.

  8. Subsurface Synthesis and Characterization of Ag Nanoparticles Embedded in MgO

    SciTech Connect

    Vilayur Ganapathy, Subramanian; Devaraj, Arun; Colby, Robert J.; Pandey, Archana; Varga, Tamas; Shutthanandan, V.; Manandhar, Sandeep; El-Khoury, Patrick Z.; Kayani, Asghar N.; Hess, Wayne P.; Thevuthasan, Suntharampillai

    2013-03-08

    Metal nanoparticles exhibit localized surface plasmon resonance (LSPR) which is very sensitive to the size and shape of the nanoparticle and the dielectric medium surrounding it. LSPR causes field enhancement near the surface of the nanoparticle making them interesting candidates for plasmonic applications. In particular, partially exposed metallic nanoparticles distributed in a dielectric matrix form hotspots which are prime locations for LSPR spectroscopy and sensing. This study involves synthesizing partially buried Ag nanoparticles in MgO and investigating the characteristics of this material system. Ag nanoparticles of different shapes and size distributions were synthesized below the surface of MgO by implanting 200 keV Ag+ ions followed by annealing at 10000C for 10 and 30 hours. A detailed optical and structural characterization was carried out to understand the evolution of Ag nanoparticle microstructure and size distribution inside the MgO matrix. Micro x-ray diffraction (MicroXRD) was employed to investigate the structural properties and estimate the crystallite size. The nanoparticles evolved from a spherical to faceted morphology with annealing time, assuming an octahedral shape truncated at the (001) planes as seen from aberration corrected transmission electron microscopy (TEM) images. The nanoparticles embedded in MgO were shown to be pure metallic Ag using atom probe tomography (APT). The nanoparticles were partially exposed to the surface employing plasma etch techniques to remove the overlaying MgO. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed to study the surface morphology and obtain a height distribution for the partially exposed nanoparticles.

  9. New characterization techniques for LSST sensors

    DOE PAGESBeta

    Nomerotski, A.

    2015-06-18

    Fully depleted, thick CCDs with extended infra-red response have become the sensor of choice for modern sky surveys. The charge transport effects in the silicon and associated astrometric distortions could make mapping between the sky coordinates and sensor coordinates non-trivial, and limit the ultimate precision achievable with these sensors. Two new characterization techniques for the CCDs, which both could probe these issues, are discussed: x-ray flat fielding and imaging of pinhole arrays.

  10. Polarization characterization of PZT disks and of embedded PZT plates by thermal wave methods

    SciTech Connect

    Eydam, Agnes Suchaneck, Gunnar Gerlach, Gerald; Esslinger, Sophia; Schönecker, Andreas; Neumeister, Peter

    2014-11-05

    In this work, the thermal wave method was applied to characterize PZT disks and embedded PZT plates with regard to the polarization magnitude and spatial homogeneity. The samples were exposed to periodic heating by means of a laser beam and the pyroelectric response was determined. Thermal relaxation times (single time constants or distributions of time constants) describe the heat losses of the PZT samples to the environment. The resulting pyroelectric current spectrum was fitted to the superposition of thermal relaxation processes. The pyroelectric coefficient gives insight in the polarization distribution. For PZT disks, the polarization distribution in the surface region showed a characteristic decrease towards the electrodes.

  11. Spectroellipsometric characterization and modeling of plasmonic diamond-like carbon nanocomposite films with embedded Ag nanoparticles.

    PubMed

    Yaremchuk, Iryna; Meškinis, Šarunas; Fitio, Volodymyr; Bobitski, Yaroslav; Šlapikas, Kestutis; Čiegis, Arvydas; Balevičius, Zigmas; Selskis, Algirdas; Tamulevičius, Sigitas

    2015-01-01

    Diamond-like carbon nanocomposite films with embedded silver nanoparticles are considered experimentally (spectroellipsometric characterization) and theoretically (modeling of optical properties). Metallic nanocomposite films were synthesized by reactive magnetron sputtering and were studied by transmission electron microscope (TEM) and atomic force microscope (AFM). The optical constants of the films were determined from spectroscopic ellipsometry measurements and were modeled using the Maxwell-Garnett approximations. Comparison between the extended and renormalized Maxwell-Garnett theory was conducted. Surface plasmon resonance peak have been found to be strongly dependent on the shape of nanoparticles and interaction between them. PMID:25977645

  12. Deterministic embedding of a single gold nanoparticle into polymeric microstructures by direct laser writing technique

    NASA Astrophysics Data System (ADS)

    Nguyen, Dam Thuy Trang; Pelissier, Aurélien; Montes, Kevin; Tong, Quang Cong; Ngo, Hoang Minh; Ledoux-Rak, Isabelle; Lai, Ngoc Diep

    2016-04-01

    We have precisely positioned and embedded a single gold nanoparticle (Au NP) into a desired polymeric photonic structure (PS) using a simple and low-cost technique called low one-photon absorption direct laser writing (LOPA DLW), with a two-step process: identification and fabrication. First, the position of the Au NP was identified with a precision of 20 nm by using DLW technique with ultralow excitation laser power (μW). This power did not induce the polymerization of the photoresist (SU8) due to its low absorption at the excitation wavelength (532 nm). Then, the structure containing the NP was fabricated by using the same DLW system with high excitation power (mW). Different 2D photonic structures have been fabricated, which contain a single Au NP at desired position. In particular, we obtained a microsphere instead of a micropillar at the position of the Au NP. The formation of such microsphere was explained by the thermal effect of the Au NP at the wavelength of 532 nm, which induced thermal polymerization of surrounding photoresist. The effect of the post-exposure bake on the quality of structures was taken into account, revealing a more efficient fabrication way by exploiting the local thermal effect of the laser. We studied further the influence of the NP size on the NP/PS coupling by investigating the fabrication and fluorescence measurement of Au NPs of different sizes: 10, 30, 50, 80, and 100 nm. The photon collection enhancements in each case were 12.9 +/- 2.5, 12.6 +/- 5.6, 3.9 +/- 2.7, 5.9 +/- 4.4, and 6.6 +/- 5.1 times, respectively. The gain in fluorescence could reach up to 36.6 times for 10-nm gold NPs.

  13. Compton back scatter imaging for mild steel rebar detection and depth characterization embedded in concrete

    NASA Astrophysics Data System (ADS)

    Margret, M.; Menaka, M.; Venkatraman, B.; Chandrasekaran, S.

    2015-01-01

    A novel non-destructive Compton scattering technique is described to ensure the feasibility, reliability and applicability of detecting the reinforcing steel bar in concrete. The indigenously developed prototype system presented in this paper is capable of detecting the reinforcement of varied diameters embedded in the concrete and as well as up to 60 mm depth, with the aid of Caesium-137(137Cs) radioactive source and a high resolution HPGe detector. The technique could also detect the inhomogeneities present in the test specimen by interpreting the material density variation caused due to the count rate. The experimental results are correlated using established techniques such as radiography and rebar locators. The results obtained from its application to locate the rebars are quite promising and also been successfully used for reinforcement mapping. This method can be applied, especially when the intrusion is located underneath the cover of the concrete or considerably at larger depths and where two sided access is restricted.

  14. New Techniques in Characterization of Ferroelectric Materials

    NASA Technical Reports Server (NTRS)

    Sehirlioglu, Alp

    2008-01-01

    Two new techniques have been developed to characterize Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) based ferroelectric single crystals: (i) electro-thermal imaging, and (ii) single crystal x-ray diffraction in the transmission mode. (i) Electro-thermal imaging is a remote sensing technique that can detect the polarization direction and poling state of a whole crystal slice. This imaging technique utilizes an IR camera to determine the field induced temperature change and does not require any special or destructive sample preparation. In the resulting images it is possible to distinguish regions of 180 deg domains. This powerful technique can be used remotely during poling to determine the poling state of the crystal to avoid over-poling that can result in inferior properties and/or cracking of the crystals. Electro-thermal imaging produced the first direct observations of polarization rotation. Under bipolar field, the domains near the corners were the first to switch direction. As the field increased above the coercive field, domains at the center part of the crystals switched direction. (ii) X-ray diffraction in the transmission mode has long been used in structure determination of organic crystals and proteins; however, it is not used much to characterize inorganic systems. 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 single crystals were examined by this XRD technique for the first time, and a never-before-seen super-lattice was revealed with a doubling of the unit cell in all three directions, giving a cell volume eight times that of a traditional perovskite unit cell. The significance of the super-lattice peaks increased with poling, indicating a structural contribution to ordering. Lack of such observations by electron diffraction in the transmission electron microscope examinations suggests the presence of a bulk effect.

  15. Techniques for physicochemical characterization of nanomaterials

    PubMed Central

    Lin, Ping-Chang; Lin, Stephen; Wang, Paul C.; Sridhar, Rajagopalan

    2014-01-01

    Advances in nanotechnology have opened up a new era of diagnosis, prevention and treatment of diseases and traumatic injuries. Nanomaterials, including those with potential for clinical applications, possess novel physicochemical properties that have an impact on their physiological interactions, from the molecular level to the systemic level. There is a lack of standardized methodologies or regulatory protocols for detection or characterization of nanomaterials. This review summarizes the techniques that are commonly used to study the size, shape, surface properties, composition, purity and stability of nanomaterials, along with their advantages and disadvantages. At present there are no FDA guidelines that have been developed specifically for nanomaterial based formulations for diagnostic or therapeutic use. There is an urgent need for standardized protocols and procedures for the characterization of nanoparticles, especially those that are intended for use as theranostics. PMID:24252561

  16. Measurement and characterization techniques for thermoelectric materials

    SciTech Connect

    Tritt, T.M.

    1997-07-01

    Characterization of thermoelectric materials can pose many problems. A temperature difference can be established across these materials as an electrical current is passed due to the Peltier effect. The thermopower of these materials is quite large and thus large thermal voltages can contribute to many of the measurements necessary to investigate these materials. This paper will discuss the chracterization techniques necessary to investigate these materials and provide an overview of some of the potential systematic errors which can arise. It will also discuss some of the corrections one needs to consider. This should provide an introduction to the characterization and measurement of thermoelectric materials and provide references for a more in depth discussion of the concepts. It should also serve as an indication of the care that must be taken while working with thermoelectric materials.

  17. Towards optimization and characterization of dye-embedded gold nanoparticle clusters for multiplexed optical imaging

    NASA Astrophysics Data System (ADS)

    McDonald, M. A.; Hight Walker, A. R.

    2009-02-01

    Metallic nanoparticle clusters coupling strong surface plasmons with a Raman reporter molecule have been developed for application in multiplexed optical imaging. Of interest to our work is the ability of the agents to serve as surface-enhanced Raman spectroscopy (SERS) probes. We present the seed-mediated synthesis and characterization of rhodamine B isothiocyante Au nanoparticle clusters (RhB-AuNPCs). RhB-AuNPCs are anisotropic structures which contain the Raman reporter, RhB, embedded between a gold aggregate core and gold surface layer. In contrast to typical SERS studies, the Raman signal originates from the probe (RhB-AuNPCs) and not from RhB incubated with a noble metal colloid. Characterization of the probes' optical properties is presented. The overall goal of our study is to prepare probes that may be used for the identification and spectroscopic labeling of multiple molecular biomarkers utilizing SERS imaging.

  18. Geologic flow characterization using tracer techniques

    SciTech Connect

    Klett, R. D.; Tyner, C. E.; Hertel, Jr., E. S.

    1981-04-01

    A new tracer flow-test system has been developed for in situ characterization of geologic formations. This report describes two sets of test equipment: one portable and one for testing in deep formations. Equations are derived for in situ detector calibration, raw data reduction, and flow logging. Data analysis techniques are presented for computing porosity and permeability in unconfined isotropic media, and porosity, permeability and fracture characteristics in media with confined or unconfined two-dimensional flow. The effects of tracer pulse spreading due to divergence, dispersion, and porous formations are also included.

  19. Photographic techniques for characterizing streambed particle sizes

    USGS Publications Warehouse

    Whitman, M.S.; Moran, E.H.; Ourso, R.T.

    2003-01-01

    We developed photographic techniques to characterize coarse (>2-mm) and fine (???2-mm) streambed particle sizes in 12 streams in Anchorage, Alaska. Results were compared with current sampling techniques to assess which provided greater sampling efficiency and accuracy. The streams sampled were wade-able and contained gravel - cobble streambeds. Gradients ranged from about 5% at the upstream sites to about 0.25% at the downstream sites. Mean particle sizes and size-frequency distributions resulting from digitized photographs differed significantly from those resulting from Wolman pebble counts for five sites in the analysis. Wolman counts were biased toward selecting larger particles. Photographic analysis also yielded a greater number of measured particles (mean = 989) than did the Wolman counts (mean = 328). Stream embeddedness ratings assigned from field and photographic observations were significantly different at 5 of the 12 sites, although both types of ratings showed a positive relationship with digitized surface fines. Visual estimates of embeddedness and digitized surface fines may both be useful indicators of benthic conditions, but digitizing surface fines produces quantitative rather than qualitative data. Benefits of the photographic techniques include reduced field time, minimal streambed disturbance, convenience of postfield processing, easy sample archiving, and improved accuracy and replication potential.

  20. Surface characterization of InP trenches embedded in oxide using scanning probe microscopy

    SciTech Connect

    Mannarino, Manuel E-mail: manuelmannarino@gmail.com; Chintala, Ravi; Vandervorst, Wilfried; Moussa, Alain; Merckling, Clement; Eyben, Pierre; Paredis, Kristof

    2015-12-14

    Metrology for structural and electrical analyses at device level has been identified as one of the major challenges to be resolved for the sub-14 nm technology nodes. In these advanced nodes, new high mobility semiconductors, such as III–V compounds, are grown in narrow trenches on a Si substrate. Probing the nature of the defects, the defect density, and the role of processing steps on the surface of such structures are prime metrology requirements. In order to enable defect analysis on a (III–V) surface, a proper sample preparation for oxide removal is of primary importance. In this work, the effectiveness of different chemical cleanings and thermal annealing procedures is investigated on both blanket InP and oxide embedded InP trenches by means of scanning probe microscopy techniques. It is found that the most effective approach is a combination of an HCl-based chemical cleaning combined with a low-temperature thermal annealing leading to an oxide free surface with atomically flat areas. Scanning tunneling microscopy (STM) has been the preferred method for such investigations on blanket films due to its intrinsic sub-nm spatial resolution. However, its application on oxide embedded structures is non-trivial. To perform STM on the trenches of interest (generally <20 nm wide), we propose a combination of non-contact atomic force microscopy and STM using the same conductive atomic force microscopy tip Our results prove that with these procedures, it is possible to perform STM in narrow InP trenches showing stacking faults and surface reconstruction. Significant differences in terms of roughness and terrace formation are also observed between the blanket and the oxide embedded InP.

  1. Surface characterization of InP trenches embedded in oxide using scanning probe microscopy

    NASA Astrophysics Data System (ADS)

    Mannarino, Manuel; Chintala, Ravi; Moussa, Alain; Merckling, Clement; Eyben, Pierre; Paredis, Kristof; Vandervorst, Wilfried

    2015-12-01

    Metrology for structural and electrical analyses at device level has been identified as one of the major challenges to be resolved for the sub-14 nm technology nodes. In these advanced nodes, new high mobility semiconductors, such as III-V compounds, are grown in narrow trenches on a Si substrate. Probing the nature of the defects, the defect density, and the role of processing steps on the surface of such structures are prime metrology requirements. In order to enable defect analysis on a (III-V) surface, a proper sample preparation for oxide removal is of primary importance. In this work, the effectiveness of different chemical cleanings and thermal annealing procedures is investigated on both blanket InP and oxide embedded InP trenches by means of scanning probe microscopy techniques. It is found that the most effective approach is a combination of an HCl-based chemical cleaning combined with a low-temperature thermal annealing leading to an oxide free surface with atomically flat areas. Scanning tunneling microscopy (STM) has been the preferred method for such investigations on blanket films due to its intrinsic sub-nm spatial resolution. However, its application on oxide embedded structures is non-trivial. To perform STM on the trenches of interest (generally <20 nm wide), we propose a combination of non-contact atomic force microscopy and STM using the same conductive atomic force microscopy tip Our results prove that with these procedures, it is possible to perform STM in narrow InP trenches showing stacking faults and surface reconstruction. Significant differences in terms of roughness and terrace formation are also observed between the blanket and the oxide embedded InP.

  2. Characterization and analysis of carbon fibre-reinforced polymer composite laminates with embedded circular vasculature

    PubMed Central

    Huang, C.-Y.; Trask, R. S.; Bond, I. P.

    2010-01-01

    A study of the influence of embedded circular hollow vascules on structural performance of a fibre-reinforced polymer (FRP) composite laminate is presented. Incorporating such vascules will lead to multi-functional composites by bestowing functions such as self-healing and active thermal management. However, the presence of off-axis vascules leads to localized disruption to the fibre architecture, i.e. resin-rich pockets, which are regarded as internal defects and may cause stress concentrations within the structure. Engineering approaches for creating these simple vascule geometries in conventional FRP laminates are proposed and demonstrated. This study includes development of a manufacturing method for forming vascules, microscopic characterization of their effect on the laminate, finite element (FE) analysis of crack initiation and failure under load, and validation of the FE results via mechanical testing observed using high-speed photography. The failure behaviour predicted by FE modelling is in good agreement with experimental results. The reduction in compressive strength owing to the embedding of circular vascules ranges from 13 to 70 per cent, which correlates with vascule dimension. PMID:20150337

  3. Embedded reference electrodes for corrosion potential monitoring, electrochemical characterization, and controlled-potential cathodic protection

    NASA Astrophysics Data System (ADS)

    Merten, Bobbi Jo Elizabeth

    A thin wire Ag/AgCl reference electrode was prepared using 50 mum Ag wire in dilute FeCl3. The wire was embedded beneath the polyurethane topcoat of two sacrificial coating systems to monitor their corrosion potential. This is the first report of a reference electrode embedded between organic coating layers to monitor substrate health. The embedded reference electrode (ERE) successfully monitored the corrosion potential of Mg primer on AA 2024-T3 for 800 days of constant immersion in dilute Harrison's solution. Zn primer on steel had low accuracy in comparison. This is in part due to short circuiting by Zn oxidation products, which are much more conductive than Mg corrosion products. Data interpretation was improved through statistical analysis. On average, ERE corrosion potentials are 0.1 to 0.2 V and 0.2 to 0.3 V more positive than a saturated calomel electrode (SCE) in solution for AA 2024-T3 and steel coating systems, respectively. Further research may confirm that ERE obtains corrosion potential information not possible by an exterior, conventional reference electrode. The ERE is stable under polarization. AA 2024-T3 was polarized to -0.95 V vs ERE to emulate controlled potential cathodic protection (CPCP) applications. Polarizations of -0.75 V vs ERE are recommended for future experiments to minimize cathodic delamination. The ERE was utilized to analyze coating mixtures of lithium carbonate, magnesium nitrate, and Mg metal on AA2024-T3. Corrosion potential, low frequency impedance by electrochemical impedance spectroscopy (EIS), and noise resistance by electrochemical noise method (ENM) were reported. Coating performance ranking is consistent with standard electrochemical characterization and visual analyses. The results suggest anti-corrosion resistance superior to a standard Mg primer following 1600 hours of B117 salt spray. Both lithium carbonate and magnesium nitrate are necessary to achieve corrosion protection. Unique corrosion protective coatings for

  4. A Micro-Computed Tomography Technique to Study the Quality of Fibre Optics Embedded in Composite Materials

    PubMed Central

    Chiesura, Gabriele; Luyckx, Geert; Voet, Eli; Lammens, Nicolas; Van Paepegem, Wim; Degrieck, Joris; Dierick, Manuel; Van Hoorebeke, Luc; Vanderniepen, Pieter; Sulejmani, Sanne; Sonnenfeld, Camille; Geernaert, Thomas; Berghmans, Francis

    2015-01-01

    Quality of embedment of optical fibre sensors in carbon fibre-reinforced polymers plays an important role in the resultant properties of the composite, as well as for the correct monitoring of the structure. Therefore, availability of a tool able to check the optical fibre sensor-composite interaction becomes essential. High-resolution 3D X-ray Micro-Computed Tomography, or Micro-CT, is a relatively new non-destructive inspection technique which enables investigations of the internal structure of a sample without actually compromising its integrity. In this work the feasibility of inspecting the position, the orientation and, more generally, the quality of the embedment of an optical fibre sensor in a carbon fibre reinforced laminate at unit cell level have been proven. PMID:25961383

  5. Optical transformation based image encryption and data embedding techniques using MATLAB

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Debalina; Ghosh, Ajay

    2015-06-01

    The proposed work describes optical transformations such as Fourier transformation and Fresnel transformation based encryption and decryption of images using random phase masks (RPMs). The encrypted images have been embedded in some secret cover files of other formats like text files, word files, audio files etc to increase the robustness in the security applications. So, if any one wants to send confidential documents, it will be difficult for the interloper to unhide the secret information. The whole work has been done in MATLAB®

  6. Complex Retrieval of Embedded IVC Filters: Alternative Techniques and Histologic Tissue Analysis

    SciTech Connect

    Kuo, William T.; Cupp, John S.; Louie, John D.; Kothary, Nishita; Hofmann, Lawrence V.; Sze, Daniel Y.; Hovsepian, David M.

    2012-06-15

    Purpose: We evaluated the safety and effectiveness of alternative endovascular methods to retrieve embedded optional and permanent filters in order to manage or reduce risk of long-term complications from implantation. Histologic tissue analysis was performed to elucidate the pathologic effects of chronic filter implantation. Methods: We studied the safety and effectiveness of alternative endovascular methods for removing embedded inferior vena cava (IVC) filters in 10 consecutive patients over 12 months. Indications for retrieval were symptomatic chronic IVC occlusion, caval and aortic perforation, and/or acute PE (pulmonary embolism) from filter-related thrombus. Retrieval was also performed to reduce risk of complications from long-term filter implantation and to eliminate the need for lifelong anticoagulation. All retrieved specimens were sent for histologic analysis. Results: Retrieval was successful in all 10 patients. Filter types and implantation times were as follows: one Venatech (1,495 days), one Simon-Nitinol (1,485 days), one Optease (300 days), one G2 (416 days), five Guenther-Tulip (GTF; mean 606 days, range 154-1,010 days), and one Celect (124 days). There were no procedural complications or adverse events at a mean follow-up of 304 days after removal (range 196-529 days). Histology revealed scant native intima surrounded by a predominance of neointimal hyperplasia and dense fibrosis in all specimens. Histologic evidence of photothermal tissue ablation was confirmed in three laser-treated specimens. Conclusion: Complex retrieval methods can now be used in select patients to safely remove embedded optional and permanent IVC filters previously considered irretrievable. Neointimal hyperplasia and dense fibrosis are the major components that must be separated to achieve successful retrieval of chronic filter implants.

  7. Characterizing odors from cattle feedlots with different odor techniques

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Odors from cattle feedlots negatively affect local communities. The purpose of this study was to characterize odors and odorants using different odor sampling techniques. Odors were characterized with field olfactometers (Nasal Ranger®), sensory techniques (GC-O) and analytical techniques (sorbent t...

  8. Synthesis, characterization and microwave absorption properties of dendrite-like Fe3O4 embedded within amorphous sugar carbon matrix

    NASA Astrophysics Data System (ADS)

    Wu, Hao; Wang, Liuding; Wu, Hongjing

    2014-01-01

    Magnetite dendrites/sugar carbon (MDs/SC) nanocomposites, embedding MDs within amorphous SC matrix, were prepared by simple carbonization-reduction method using α-Fe2O3 dendrites (HDs) as precursor of MDs and sucrose as SC source, while still maintain the dendritic shape of the precursor. The morphology, composition, structure and static magnetic properties of the as-prepared MDs/SC nanocomposites were characterized by various techniques thoroughly. Particularly, the electromagnetic and microwave absorption properties of the MDs/SC and MDs paraffin composites (40 wt.%) were compared over 2-14 GHz. The results show that the microwave absorption performance of MDs/SC samples is comparable or even superior to that of MDs case. The absorption band with reflection loss (RL) below -20 dB for one of the MDs/SC samples can cover the whole X-band (8-12 GHz) with thickness of 1.8-2.4 mm when the content of MDs in the MDs/SC nanocomposite is 25.8 wt.%, and the minimum RL can reach -49.9 dB at 12.1 GHz when the layer thickness is only 1.9 mm. The excellent microwave absorption properties of the MDs/SC paraffin composites are attributed to the proper match between the complex permittivity and permeability, and the unique fractal structures of MDs.

  9. Powering embedded electronics for wind turbine monitoring using multi-source energy harvesting techniques

    NASA Astrophysics Data System (ADS)

    Anton, S. R.; Taylor, S. G.; Raby, E. Y.; Farinholt, K. M.

    2013-03-01

    With a global interest in the development of clean, renewable energy, wind energy has seen steady growth over the past several years. Advances in wind turbine technology bring larger, more complex turbines and wind farms. An important issue in the development of these complex systems is the ability to monitor the state of each turbine in an effort to improve the efficiency and power generation. Wireless sensor nodes can be used to interrogate the current state and health of wind turbine structures; however, a drawback of most current wireless sensor technology is their reliance on batteries for power. Energy harvesting solutions present the ability to create autonomous power sources for small, low-power electronics through the scavenging of ambient energy; however, most conventional energy harvesting systems employ a single mode of energy conversion, and thus are highly susceptible to variations in the ambient energy. In this work, a multi-source energy harvesting system is developed to power embedded electronics for wind turbine applications in which energy can be scavenged simultaneously from several ambient energy sources. Field testing is performed on a full-size, residential scale wind turbine where both vibration and solar energy harvesting systems are utilized to power wireless sensing systems. Two wireless sensors are investigated, including the wireless impedance device (WID) sensor node, developed at Los Alamos National Laboratory (LANL), and an ultra-low power RF system-on-chip board that is the basis for an embedded wireless accelerometer node currently under development at LANL. Results indicate the ability of the multi-source harvester to successfully power both sensors.

  10. An Efficient Algorithm Embedded in an Ultrasonic Visualization Technique for Damage Inspection Using the AE Sensor Excitation Method

    PubMed Central

    Liu, Yaolu; Goda, Riu; Samata, Kiyoshi; Kanda, Atsushi; Hu, Ning; Zhang, Jianyu; Ning, Huiming; Wu, Liangke

    2014-01-01

    To improve the reliability of a Lamb wave visualization technique and to obtain more information about structural damages (e.g., size and shape), we put forward a new signal processing algorithm to identify damage more clearly in an inspection region. Since the kinetic energy of material particles in a damaged area would suddenly change when ultrasonic waves encounter the damage, the new algorithm embedded in the wave visualization technique is aimed at monitoring the kinetic energy variations of all points in an inspection region to construct a damage diagnostic image. To validate the new algorithm, three kinds of surface damages on the center of aluminum plates, including two non-penetrative slits with different depths and a circular dent, were experimentally inspected. From the experimental results, it can be found that the new algorithm can remarkably enhance the quality of the diagnostic image, especially for some minor defects. PMID:25356647

  11. Stationary phases with special structural properties for high-throughput separation techniques: preparation, characterization and applications.

    PubMed

    Buszewski, Boguslaw; Welerowicz, Tomasz

    2004-06-01

    Stationary phases with specific structural properties for high-throughput liquid chromatographic (LC) techniques are described. Special attention was paid to phases with special structural properties, mainly containing internal functional group (e.g. amide). Such materials are generally called "embedded phases". There are phases created in amidation process of aminopropylated silica gel, especially phases based on biological compounds, like phospholipids and cholesterol, which are called immobilized artificial membranes (IAM's). The synthesis and applications of polar embedded amide LC stationary phases were also reviewed. Methods of characterization of synthesized packing materials were presented, with general focusing on spectroscopic measurements like (13C and 29Si CP/MAS NMR and FT-IR), elemental and thermal analysis as well as chromatographic quantitative structure-retention relationships (QSRR) and extended chemometric tests. The potential applications of various dedicated stationary phases in a high-throughput LC screening procedures were also presented. PMID:15200378

  12. Characterization of polymer monoliths containing embedded nanoparticles by scanning transmission X-ray microscopy (STXM).

    PubMed

    Arrua, R Dario; Hitchcock, Adam P; Hon, Wei Boon; West, Marcia; Hilder, Emily F

    2014-03-18

    The structural and chemical homogeneity of monolithic columns is a key parameter for high efficiency stationary phases in liquid chromatography. Improved characterization techniques are needed to better understand the polymer morphology and its optimization. Here the analysis of polymer monoliths by scanning transmission X-ray microscopy (STXM) is presented for the first time. Poly(butyl methacrylate-co-ethyleneglycoldimethacrylate) [poly(BuMA-co-EDMA)] monoliths containing encapsulated divinylbenzene (DVB) nanoparticles were characterized by STXM, which gives a comprehensive, quantitative chemical analysis of the monolith at a spatial resolution of 30 nm. The results are compared with other methods commonly used for the characterization of polymer monoliths [scanning electron microscopy (SEM), transmission electron microscopy (TEM), mercury porosimetry, and nitrogen adsorption]. The technique permitted chemical identification and mapping of the nanoparticles within the polymeric scaffold. Residual surfactant, which was used during the manufacture of the nanoparticles, was also detected. We show that STXM can give more in-depth chemical information for these types of materials and therefore lead to a better understanding of the link between polymer morphology and chromatographic performance. PMID:24552424

  13. At wavelength observation of phase defect embedded in EUV mask using microscope technique

    NASA Astrophysics Data System (ADS)

    Terasawa, Tsuneo; Amano, Tsuyoshi; Yamane, Takeshi; Watanabe, Hidehiro; Toyoda, Mitsunori; Harada, Tetsuo; Watanabe, Takeo; Kinoshita, Hiroo

    2014-04-01

    The effect of phase defect on extreme ultraviolet (EUV) lithography was examined using an EUV microscope. A test mask containing periodic absorber line patterns and programmed pit phase defects embedded in a multilayer-coated mask blank was prepared, and the mask patterns were observed by the EUV microscope developed by Tohoku University and constructed at the site of a beam line of the New SUBARU of the University of Hyogo. The half pitches of the absorber patterns were 64 nm and 44 nm at mask which corresponded to 16 nm and 11 nm device generations. The programmed defects included not only square-shape defects but also rectangular-shape defects with different orientations. When a phase defect was located between two adjacent absorber patterns, then the observation image intensity of the absorber lines and spaces (L/S) patterns varied, and the impact of a phase defect was predicted as an intensity variation of bright space image. Phase defect location dependency and defect shape dependency of the observation image intensity were examined. The effectiveness of the EUV microscope to predict the phase defect impacts was confirmed.

  14. Laboratory Techniques in Geology: Embedding Analytical Methods into the Undergraduate Curriculum

    NASA Astrophysics Data System (ADS)

    Baedke, S. J.; Johnson, E. A.; Kearns, L. E.; Mazza, S. E.; Gazel, E.

    2014-12-01

    Paid summer REU experiences successfully engage undergraduate students in research and encourage them to continue to graduate school and scientific careers. However these programs only accommodate a limited number of students due to funding constraints, faculty time commitments, and limited access to needed instrumentation. At JMU, the Department of Geology and Environmental Science has embedded undergraduate research into the curriculum. Each student fulfilling a BS in Geology or a BA in Earth Science completes 3 credits of research, including a 1-credit course on scientific communication, 2 credits of research or internship, followed by a presentation of that research. Our department has successfully acquired many analytical instruments and now has an XRD, SEM/EDS, FTIR, handheld Raman, AA, ion chromatograph, and an IRMS. To give as many students as possible an overview to the scientific uses and operation methods for these instruments, we revived a laboratory methods course that includes theory and practical use of instrumentation at JMU, plus XRF sample preparation and analysis training at Virginia Tech during a 1-day field trip. In addition to practical training, projects included analytical concepts such as evaluating analytical vs. natural uncertainty, determining error on multiple measurements, signal-to-noise ratio, and evaluating data quality. State funding through the 4-VA program helped pay for analytical supplies and support for students to complete research projects over the summer or during the next academic year using instrumentation from the course. This course exemplifies an alternative path to broadening participation in undergraduate research and creating stronger partnerships between PUI's and research universities.

  15. Electrokinetic characterization techniques for contaminated soils

    SciTech Connect

    Eykholt, G.R.; Hung, H.

    1995-12-31

    One important element to the success of electrokinetic remediation of contaminated soils may be the assessment and control of the soil surface chemistry. This is usually reflected by an operative zeta-potential or electroosmotic coefficient, k{sub eo}, found by an electroosmosis test on a plug of contaminated soil. However, several researchers have shown that both the magnitude and uniformity of k{sub eo} change over the course of testing, as does the electric field intensity and zeta-potential, two basic parameters of the fundamental driving force. The electric field intensity can be measured during the test, but it is more difficult to assess the zeta potential. Independent techniques are needed. A conventional technique is dilute electrophoresis, but this test may not be truly representative or convenient. In this research summary, alternative techniques based on electroacoustic phenomena are presented in conjunction with other electrokinetic tests on reference and contaminated soils.

  16. Direct fluorescent antibody technique for the detection of bacterial kidney disease in paraffin-embedded tissues

    USGS Publications Warehouse

    Ochiai, T.; Yasutake, W.T.; Gould, R.W.

    1985-01-01

    The direct fluorescent antibody technique (FAT) was successfully used to detect the causative agent of bacterial kidney disease (BKD), Renibacterium salmoninarum, in Bouin's solution flexed and paraffinembedded egg and tissue sections. This method is superior to gram stain and may be particularly useful in detecting the BKD organism in fish with low-grade infection.

  17. Embedded sensors in layered manufacturing

    NASA Astrophysics Data System (ADS)

    Li, Xiaochun

    Layered Manufacturing can be applied to build ``smart'' parts with sensors, integrated circuits, and actuators placed within the component. Embedded sensors can be used to gain data for validating or improving designs during the prototype stage or to obtain information on the performance and structural integrity of components in service. Techniques for embedding fiber optic sensors in metals, polymers, and ceramics have been investigated. Embedding optical fibers into metals is especially challenging because engineering alloys tend to exhibit high melting temperatures. In the present research an embedding sequence was developed capable of embedding fiber sensors into parts made of metal alloys with high melting temperatures. Fiber Bragg Grating (FBG) sensors were selected as the most promising sensor candidate. The embedded FBG sensors were characterized for temperature and strain measurements. The embedded FBG sensors in nickel and stainless steel provided high sensitivity, good accuracy, and high temperature capacity for temperature measurements. Temperature sensitivity approximately 100% higher than that of bare FBGs was demonstrated. For strain measurements, the sensors embedded in metal and polyurethane yielded high sensitivity, accuracy, and linearity. The sensitivity of the embedded FBGs was in good agreement with that of bare FBGs. Moreover, a decoupling technique for embedded FBG sensors was developed to separate temperature and strain effects. The embedded FBG sensors were used to monitor the accumulation of residual stresses during the laser- assisted Layered Manufacturing, to measure the strain field in layered materials, to measure pressure, and to monitor temperature and strain simultaneously. New techniques have been developed for temperature and strain measurements of rotating components with FBG sensors embedded or attached to the surface. Tunable laser diodes were incorporated into the sensing system for monitoring the Bragg grating wavelength

  18. The tissue is the issue: improved methylome analysis from paraffin-embedded tissues by application of the HOPE technique.

    PubMed

    Marwitz, Sebastian; Kolarova, Julia; Reck, Martin; Reinmuth, Niels; Kugler, Christian; Schädlich, Ines; Haake, Andrea; Zabel, Peter; Vollmer, Ekkehard; Siebert, Reiner; Goldmann, Torsten; Ammerpohl, Ole

    2014-08-01

    Alterations in the DNA methylome are characteristic for numerous diseases and a typical hallmark of cancer. Therefore, DNA methylation is currently under investigation in research labs and has also entered diagnostics. Recently, protocols like the BeadChip technology have become commercially available to study DNA methylation in an array format and semiquantitative fashion. However, it is known that fixation of the sample material with formalin prior to BeadChip analysis can affect the results. In this study we compared the influence of fixation on the outcome of BeadChip analysis. From six patients each a lung cancer tissue sample and a corresponding tumor-free lung tissue sample were collected. The samples were separated into three pieces. One piece of each sample was fixed with formalin, another one by the non-cross-linking HOPE technique (Hepes-glutamic acid buffer mediated Organic solvent Protection Effect). Subsequently, both became paraffin embedded. As a reference, the remaining third piece was cryopreserved. In addition we used three adenocarcinoma cell lines (H838, A549, and H1650) to validate the results from patient tissues. We show that using the HOPE technique instead of formalin largely prevents the introduction of formalin-fixation related artifacts. An ANOVA analysis significantly separated HOPE- and cryopreserved from formalin-fixed samples (FDR<0.05), while differences in the methylation data obtained from HOPE-fixed and cryopreserved material were minor. Consequently, HOPE fixation is superior to formalin fixation if a subsequent BeadChip analysis of paraffin-embedded sample material is intended. PMID:24933424

  19. A vision-based driver nighttime assistance and surveillance system based on intelligent image sensing techniques and a heterogamous dual-core embedded system architecture.

    PubMed

    Chen, Yen-Lin; Chiang, Hsin-Han; Chiang, Chuan-Yen; Liu, Chuan-Ming; Yuan, Shyan-Ming; Wang, Jenq-Haur

    2012-01-01

    This study proposes a vision-based intelligent nighttime driver assistance and surveillance system (VIDASS system) implemented by a set of embedded software components and modules, and integrates these modules to accomplish a component-based system framework on an embedded heterogamous dual-core platform. Therefore, this study develops and implements computer vision and sensing techniques of nighttime vehicle detection, collision warning determination, and traffic event recording. The proposed system processes the road-scene frames in front of the host car captured from CCD sensors mounted on the host vehicle. These vision-based sensing and processing technologies are integrated and implemented on an ARM-DSP heterogamous dual-core embedded platform. Peripheral devices, including image grabbing devices, communication modules, and other in-vehicle control devices, are also integrated to form an in-vehicle-embedded vision-based nighttime driver assistance and surveillance system. PMID:22736956

  20. High frequency characterization of conductive inks embedded within a structural composite

    NASA Astrophysics Data System (ADS)

    Pa, Peter; McCauley, Raymond; Larimore, Zachary; Mills, Matthew; Yarlaggada, Shridhar; Mirotznik, Mark S.

    2015-06-01

    Woven fabric composites provide an attractive platform for integrating electromagnetic functionality—such as conformal load-bearing antennas and frequency selective surfaces—into a structural platform. One practical fabrication method for integrating conductive elements within a woven fabric composite system involves using additive manufacturing systems such as screen printing. While screen printing is an inherently scalable, flexible and cost effective method, little is known about the high frequency electrical properties of its conductive inks when they are embedded within the woven fabric composite. Thus, we have completed numerical and experimental studies to determine the electrical conductivity of screen printable conductive inks that are embedded within this composite. We have also performed mechanical studies to evaluate how printing affects the structural performance of the composite.

  1. Synthesis, characterization, UV and dielectric properties of hexagonal disklike ZnO particles embedded in polyimides

    SciTech Connect

    Vural, Sema; Koeytepe, Sueleyman; Seckin, Turgay; Adiguezel, Ibrahim

    2011-10-15

    Graphical abstract: The hexagonal disklike ZnO particles with a diameter of 300-500 nm were synthesized from zinc acetate and NaOH in water with citric acid. ZnO/polyimide composite films with different ZnO contents was prepared. The prepared zinc oxide-polyimide composites were characterized for their structure, morphology and thermal behavior. Composites with ZnO particle contents from 1 to 5 wt% show good transparency in the visible region and luminescent properties. Highlights: {yields} A series of novel ZnO/polyimide composite films with different ZnO contents was prepared. {yields} The ZnO was homogeneously dispersed in the PI matrix. {yields} The composites showed the low dielectric constant of 50 at 10{sup 6} Hz. {yields} Homogenous dispersion and the amount of ZnO particles contributed to the dielectric properties of composites. -- Abstract: A series of novel ZnO/polyimide composite films with different ZnO contents was prepared through incorporation hexagonal disklike ZnO particles into poly(amic acid) of the pre polymer of the polyimide. The hexagonal disklike ZnO particles with a diameter of 300-500 nm were synthesized from zinc acetate and NaOH in water with citric acid. The prepared zinc oxide-polyimide composites were characterized for their structure, morphology, and thermal behavior employing Fourier transform infrared spectroscopy, scanning electron micrograph, X-ray diffraction and thermal analysis techniques. Thermal analyses show that the ZnO particles were successfully incorporated into the polymer matrix and these ZnO/polymer composites have a good thermal stability. Scanning electron microscopy studies indicate the ZnO particles were uniformly dispersed in the polymer and they remained at the original size (300-500 nm) before immobilization. All composite films with ZnO particle contents from 1 to 5 wt% show good transparency in the visible region and luminescent properties.

  2. Electrical characterization of a Mapham inverter using pulse testing techniques

    NASA Technical Reports Server (NTRS)

    Baumann, E. D.; Myers, I. T.; Hammoud, A. N.

    1990-01-01

    The use of a multiple pulse testing technique to determine the electrical characteristics of large megawatt-level power systems for aerospace missions is proposed. An innovative test method based on the multiple pulse technique is demonstrated on a 2-kW Mapham inverter. The concept of this technique shows that characterization of large power systems under electrical equilibrium at rated power can be accomplished without large costly power supplies. The heat generation that occurs in systems when tested in a continuous mode is eliminated. The results indicate that there is a good agreement between this testing technique and that of steady state testing.

  3. Electrical characterization of a Mapham inverter using pulse testing techniques

    NASA Astrophysics Data System (ADS)

    Baumann, E. D.; Myers, I. T.; Hammoud, A. N.

    The use of a multiple pulse testing technique to determine the electrical characteristics of large megawatt-level power systems for aerospace missions is proposed. An innovative test method based on the multiple pulse technique is demonstrated on a 2-kW Mapham inverter. The concept of this technique shows that characterization of large power systems under electrical equilibrium at rated power can be accomplished without large costly power supplies. The heat generation that occurs in systems when tested in a continuous mode is eliminated. The results indicate that there is a good agreement between this testing technique and that of steady state testing.

  4. Determination of estrogen receptors in paraffin-embedded tissue. Techniques and the value in breast cancer treatment.

    PubMed

    Andersen, J

    1992-01-01

    Estrogen receptor (ER) analysis in breast cancer has been used in three clinical situations: to select patients with advanced breast cancer for hormonal therapy, as a prognostic parameter, and for selection of women with early breast cancer to adjuvant hormonal treatment. ER has traditionally been measured using labelled hormone in binding assays--often in dextran-coated charcoal assays (DCC). Monoclonal antibodies to ER has permitted development of a solid phase enzyme immunoassay (ER-EIA) used for quantitative determination of ER in tissue homogenates, and have also been used for determination of ER using an immunohistochemical assay in frozen sections (ER-ICA) or in formalin-fixed, paraffin-embedded tissue (ER-PAR). A large number of studies has compared ER-EIA with ER-DCC assays. There is a good linear correlation between the two types of assay but ER-EIA measure more ER and classify a larger fraction of tumors ER-positive than conventional ER assays. Lack of clinical data makes the significance of this uncertain. Numerous studies have reported on the correlation between ER-ICA and ER-DCC or ER-EIA. There is a good correlation among the assays on classification of ER status with a median 86% concordance, but a somewhat poorer correlation between semiquantified ER of immunohistochemical assays and ER determined by the quantitative methods (median coefficient of correlation 0.67). There is a large variation in the cut-off level for definition of ER-positive in immunohistochemical assays emphasizing the need for quality control studies. The major problem involved in ER analysis in paraffin-embedded tissue is a considerable loss of immunoreactivity compared to sections from frozen tissue. This can partly be overcome by modifications of the immunohistochemical technique using enzyme pretreatment and other amplification systems, but the sensitivity of ER-PAR remains lower than ER-ICA despite these modifications, and the ER status is less reliably determined in tumors

  5. Compression embedding

    DOEpatents

    Sandford, II, Maxwell T.; Handel, Theodore G.; Bradley, Jonathan N.

    1998-01-01

    A method of embedding auxiliary information into the digital representation of host data created by a lossy compression technique. The method applies to data compressed with lossy algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as integer indices having redundancy and uncertainty in value by one unit. Indices which are adjacent in value are manipulated to encode auxiliary data. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user. Lossy compression methods use loss-less compressions known also as entropy coding, to reduce to the final size the intermediate representation as indices. The efficiency of the compression entropy coding, known also as entropy coding is increased by manipulating the indices at the intermediate stage in the manner taught by the method.

  6. Compression embedding

    DOEpatents

    Sandford, M.T. II; Handel, T.G.; Bradley, J.N.

    1998-03-10

    A method of embedding auxiliary information into the digital representation of host data created by a lossy compression technique is disclosed. The method applies to data compressed with lossy algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as integer indices having redundancy and uncertainty in value by one unit. Indices which are adjacent in value are manipulated to encode auxiliary data. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user. Lossy compression methods use loss-less compressions known also as entropy coding, to reduce to the final size the intermediate representation as indices. The efficiency of the compression entropy coding, known also as entropy coding is increased by manipulating the indices at the intermediate stage in the manner taught by the method. 11 figs.

  7. Optical characterization of ZnS coated CdS nanorods embedded in liquid crystals

    NASA Astrophysics Data System (ADS)

    Roy, J. S.; Majumder, T. Pal; Dabrowski, R.

    2016-05-01

    The photoluminescence (PL) emission intensity of ZnS coated CdS nanorods, represented by CdS/ZnS system, have been enhanced in presence of liquid crystals (LC) and the enhancement strongly depends on concentration of LC. The highly light scattering liquid crystalline phase causes the enhancement in PL intensity. It is also observed that the PL intensity of CdS nanorods enhances with the coating of ZnS material. This enhancement in PL intensity is ascribed by the fact that the high optical band gap ZnS material prevents the tunneling of the charge carriers from the core CdS nanorods and passivated nonradiative recombination sites which are existed on the core surfaces. Finally, 5 fold enhancements in PL intensity of CdS nanorods have been observed by coating with ZnS material and then embedding in LC. We have also observed the red shift in emission energy band of CdS/ZnS system embedded in LC. This study will provide a possible way to develop smart optoelectronics devices.

  8. Analysis and characterization of structurally embedded vascular antennas using liquid metals

    NASA Astrophysics Data System (ADS)

    Hartl, Darren J.; Huff, Gregory H.; Pan, Hong; Smith, Lisa; Bradford, Robyn L.; Frank, Geoffrey J.; Baur, Jeffrey W.

    2016-04-01

    Over the past decade, a large body of research associated with the addition of microvascular networks to structural composites has been generated. The engineering goal is most often the extension of structural utility to include extended functionalities such as self-healing or improved thermal management and resilience. More recently, efforts to design reconfigurable embedded electronics via the incorporation of non-toxic liquid metals have been initiated. A wide range of planar antenna configurations are possible, and the trade-offs between structural effects, other system costs, and increased flexibility in transmitting and receiving frequencies are being explored via the structurally embedded vascular antenna (SEVA) concept. This work describes for the first time the design of a bowtie-like tunable liquid metal-based antenna for integration into a structural composite for electromagnetic use. The design of both the solid/fluid feed structure and fluid transmission lines are described and analysis results regarding the RF performance of the antenna are provided. Fabrication methods for the SEVA are explained in detail and as-fabricated components are described. Challenges associated with both fabrication and system implementation and testing are elucidated. Results from preliminary RF testing indicate that in situ response tuning is feasible in these novel multifunctional composites.

  9. Statistical techniques for the characterization of partially observed epidemics.

    SciTech Connect

    Safta, Cosmin; Ray, Jaideep; Crary, David; Cheng, Karen

    2010-11-01

    Techniques appear promising to construct and integrate automated detect-and-characterize technique for epidemics - Working off biosurveillance data, and provides information on the particular/ongoing outbreak. Potential use - in crisis management and planning, resource allocation - Parameter estimation capability ideal for providing the input parameters into an agent-based model, Index Cases, Time of Infection, infection rate. Non-communicable diseases are easier than communicable ones - Small anthrax can be characterized well with 7-10 days of data, post-detection; plague takes longer, Large attacks are very easy.

  10. Application of Material Characterization Techniques to Electrical Forensic Analysis

    SciTech Connect

    Mills, T.D.

    2003-03-11

    The application of forensic science techniques to electrical equipment failure investigation has not been widely documented in the engineering world. This paper is intended to share an example of using material characterization techniques to support an initial cause determination of an electrical component failure event. The resulting conclusion supported the initial cause determination and ruled out the possibility of design deficiencies. Thus, the qualification testing of the equipment was allowed to continue to successful completion.

  11. Polarized light scattering technique for morphological characterization of waterborne pathogens

    NASA Astrophysics Data System (ADS)

    Devarakonda, Venkat V.; Manickavasagam, Sivakumar

    2009-05-01

    We have recently developed an elliptically polarized light scattering (EPLS) technique to characterize the morphology of fine particles suspended in an optically non-absorbing medium such as water. This technique provides the size distribution, shape and agglomeration characteristics of suspended particles. This technique can be used to detect various types of biological pathogens such as bacteria, protozoa and viruses in potable water systems. Here we report results obtained from EPLS measurements on two strains of Bacillus spores suspended in water along with comparison with electron microscopy.

  12. Analytical technique characterizes all trace contaminants in water

    NASA Technical Reports Server (NTRS)

    Foster, J. N.; Lysyj, I.; Nelson, K. H.

    1967-01-01

    Properly programmed combination of advanced chemical and physical analytical techniques characterize critically all trace contaminants in both the potable and waste water from the Apollo Command Module. This methodology can also be applied to the investigation of the source of water pollution.

  13. Physical and chemical characterization techniques for metallic powders

    SciTech Connect

    Slotwinski, J. A.; Stutzman, P. E.; Ferraris, C. F.; Watson, S. S.; Peltz, M. A.; Garboczi, E. J.

    2014-02-18

    Systematic studies have been carried out on two different powder materials used for additive manufacturing: stainless steel and cobalt-chrome. An extensive array of characterization techniques were applied to these two powders. The physical techniques included laser-diffraction particle-size analysis, X-ray computed tomography for size and shape analysis, and optical and scanning electron microscopy. Techniques sensitive to chemistry included X-ray diffraction and energy-dispersive analytical X-ray analysis. The background of these techniques will be summarized and some typical findings comparing different samples of virgin additive manufacturing powders, taken from the same lot, will be given. The techniques were used to confirm that different samples of powder from the same lot were essentially identical, within the uncertainty of the measurements.

  14. Characterization of microstructure with low frequency electromagnetic techniques

    SciTech Connect

    Cherry, Matthew R.; Sathish, Shamachary; Pilchak, Adam L.; Blodgett, Mark P.; Cherry, Aaron J.

    2014-02-18

    A new computational method for characterizing the relationship between surface crystallography and electrical conductivity in anisotropic materials with low frequency electromagnetic techniques is presented. The method is discussed from the standpoint of characterizing the orientation of a single grain, as well as characterizing statistical information about grain ensembles in the microstructure. Large-area electron backscatter diffraction (EBSD) data was obtained and used in conjunction with a synthetic aperture approach to simulate the eddy current response of beta annealed Ti-6Al-4V. Experimental eddy current results are compared to the computed eddy current approximations based on electron backscatter diffraction (EBSD) data, demonstrating good agreement. The detectability of notches in the presence of noise from microstructure is analyzed with the described simulation method and advantages and limitations of this method are discussed relative to other NDE techniques for such analysis.

  15. Nanostructure Embedded Microchips for Detection, Isolation, and Characterization of Circulating Tumor Cells

    PubMed Central

    2015-01-01

    Conspectus Circulating tumor cells (CTCs) are cancer cells that break away from either a primary tumor or a metastatic site and circulate in the peripheral blood as the cellular origin of metastasis. With their role as a “tumor liquid biopsy”, CTCs provide convenient access to all disease sites, including that of the primary tumor and the site of fatal metastases. It is conceivable that detecting and analyzing CTCs will provide insightful information in assessing the disease status without the flaws and limitations encountered in performing conventional tumor biopsies. However, identifying CTCs in patient blood samples is technically challenging due to the extremely low abundance of CTCs among a large number of hematologic cells. To address this unmet need, there have been significant research endeavors, especially in the fields of chemistry, materials science, and bioengineering, devoted to developing CTC detection, isolation, and characterization technologies. Inspired by the nanoscale interactions observed in the tissue microenvironment, our research team at UCLA pioneered a unique concept of “NanoVelcro” cell-affinity substrates, in which CTC capture agent-coated nanostructured substrates were utilized to immobilize CTCs with high efficiency. The working mechanism of NanoVelcro cell-affinity substrates mimics that of Velcro: when the two fabric strips of a Velcro fastener are pressed together, tangling between the hairy surfaces on two strips leads to strong binding. Through continuous evolution, three generations (gens) of NanoVelcro CTC chips have been established to achieve different clinical utilities. The first-gen NanoVelcro chip, composed of a silicon nanowire substrate (SiNS) and an overlaid microfluidic chaotic mixer, was created for CTC enumeration. Side-by-side analytical validation studies using clinical blood samples suggested that the sensitivity of first-gen NanoVelcro chip outperforms that of FDA-approved CellSearch. In conjunction with

  16. Nanostructure embedded microchips for detection, isolation, and characterization of circulating tumor cells.

    PubMed

    Lin, Millicent; Chen, Jie-Fu; Lu, Yi-Tsung; Zhang, Yang; Song, Jinzhao; Hou, Shuang; Ke, Zunfu; Tseng, Hsian-Rong

    2014-10-21

    Circulating tumor cells (CTCs) are cancer cells that break away from either a primary tumor or a metastatic site and circulate in the peripheral blood as the cellular origin of metastasis. With their role as a "tumor liquid biopsy", CTCs provide convenient access to all disease sites, including that of the primary tumor and the site of fatal metastases. It is conceivable that detecting and analyzing CTCs will provide insightful information in assessing the disease status without the flaws and limitations encountered in performing conventional tumor biopsies. However, identifying CTCs in patient blood samples is technically challenging due to the extremely low abundance of CTCs among a large number of hematologic cells. To address this unmet need, there have been significant research endeavors, especially in the fields of chemistry, materials science, and bioengineering, devoted to developing CTC detection, isolation, and characterization technologies. Inspired by the nanoscale interactions observed in the tissue microenvironment, our research team at UCLA pioneered a unique concept of "NanoVelcro" cell-affinity substrates, in which CTC capture agent-coated nanostructured substrates were utilized to immobilize CTCs with high efficiency. The working mechanism of NanoVelcro cell-affinity substrates mimics that of Velcro: when the two fabric strips of a Velcro fastener are pressed together, tangling between the hairy surfaces on two strips leads to strong binding. Through continuous evolution, three generations (gens) of NanoVelcro CTC chips have been established to achieve different clinical utilities. The first-gen NanoVelcro chip, composed of a silicon nanowire substrate (SiNS) and an overlaid microfluidic chaotic mixer, was created for CTC enumeration. Side-by-side analytical validation studies using clinical blood samples suggested that the sensitivity of first-gen NanoVelcro chip outperforms that of FDA-approved CellSearch. In conjunction with the use of the

  17. Development and Characterization of Embedded Sensory Particles Using Multi-Scale 3D Digital Image Correlation

    NASA Technical Reports Server (NTRS)

    Cornell, Stephen R.; Leser, William P.; Hochhalter, Jacob D.; Newman, John A.; Hartl, Darren J.

    2014-01-01

    A method for detecting fatigue cracks has been explored at NASA Langley Research Center. Microscopic NiTi shape memory alloy (sensory) particles were embedded in a 7050 aluminum alloy matrix to detect the presence of fatigue cracks. Cracks exhibit an elevated stress field near their tip inducing a martensitic phase transformation in nearby sensory particles. Detectable levels of acoustic energy are emitted upon particle phase transformation such that the existence and location of fatigue cracks can be detected. To test this concept, a fatigue crack was grown in a mode-I single-edge notch fatigue crack growth specimen containing sensory particles. As the crack approached the sensory particles, measurements of particle strain, matrix-particle debonding, and phase transformation behavior of the sensory particles were performed. Full-field deformation measurements were performed using a novel multi-scale optical 3D digital image correlation (DIC) system. This information will be used in a finite element-based study to determine optimal sensory material behavior and density.

  18. Characterization of LiF/CuO-Codoped BaTiO3 for Embedded Capacitors

    NASA Astrophysics Data System (ADS)

    Lee, Kyoungho

    2015-03-01

    Sintering additives for BaTiO3 were studied in order to facilitate the use of BaTiO3 as a material for embedded decoupling capacitors in high-density multilayered low-temperature cofired ceramic (LTCC) modules for mobile communication systems and three-dimensional (3D) printing modules. Among the studied additives, the CuO/LiF mixture was the most promising sintering additive for cofiring BaTiO3 with a commercial low-permittivity ( ɛ r) LTCC sheet (MLS-22, NEG Co.). The temperature dependence of the dielectric properties of BaTiO3 was successfully controlled by adjusting the CuO/LiF amount and ratio and the sintering temperature. BaTiO3 codoped with 10 wt.% LiF/CuO (1:1 ratio) and sintered at 860°C for 30 min showed 95% sintering density. The room-temperature permittivity ( ɛ r) of LiF/CuO-codoped BaTiO3 was 1620 at 1 MHz, and the temperature coefficient of capacitance satisfied the X5R specification. After cofiring this LiF/CuO-codoped BaTiO3 ceramic with an MLS-22 sheet at 860°C, there was no crack formation at the layer boundary. Also a chemical compatibility test revealed that there were no severe reactions between the LiF/CuO-codoped BaTiO3 and an Ag electrode.

  19. Development and characterization of silicone embedded distributed piezoelectric sensors for contact detection

    NASA Astrophysics Data System (ADS)

    Acer, Merve; Salerno, Marco; Agbeviade, Kossi; Paik, Jamie

    2015-07-01

    Tactile sensing transfers complex interactive information in a most intuitive sense. Such a populated set of data from the environment and human interactions necessitates various degrees of information from both modular and distributed areas. A sensor design that could provide such types of feedback becomes challenging when the target component has a nonuniform, agile, high resolution, and soft surface. This paper presents an innovative methodology for the manufacture of novel soft sensors that have a high resolution sensing array due to the sensitivity of ceramic piezoelectric (PZT) elements, while uncommonly matched with the high stretchability of the soft substrate and electrode design. Further, they have a low profile and their transfer function is easy to tune by changing the material and thickness of the soft substrate in which the PZTs are embedded. In this manuscript, we present experimental results of the soft sensor prototypes: PZTs arranged in a four by two array form, measuring 1.5-2.3 mm in thickness, with the sensitivity in the range of 0.07-0.12 of the normalized signal change per unit force. We have conducted extensive tests under dynamic loading conditions that include impact, step and cyclic. The presented prototype's mechanical and functional capacities are promising for applications in biomedical systems where soft, wearable and high precision sensors are needed.

  20. Application of the FICTION technique for the simultaneous detection of immunophenotype and chromosomal abnormalities in routinely fixed, paraffin wax embedded bone marrow trephines

    PubMed Central

    Korać, P; Jones, M; Dominis, M; Kušec, R; Mason, D Y; Banham, A H; Ventura, R A

    2005-01-01

    The use of interphase fluorescence in situ hybridisation (FISH) to study cytogenetic abnormalities in routinely fixed paraffin wax embedded tissue has become commonplace over the past decade. However, very few studies have applied FISH to routinely fixed bone marrow trephines (BMTs). This may be because of the acid based decalcification methods that are commonly used during the processing of BMTs, which may adversely affect the suitability of the sample for FISH analysis. For the first time, this report describes the simultaneous application of FISH and immunofluorescent staining (the FICTION technique) to formalin fixed, EDTA decalcified and paraffin wax embedded BMTs. This technique allows the direct correlation of genetic abnormalities to immunophenotype, and therefore will be particularly useful for the identification of genetic abnormalities in specific tumour cells present in BMTs. The application of this to routine clinical practice will assist diagnosis and the detection of minimal residual disease. PMID:16311361

  1. New microarchitectures of (Er,Yb):Lu2O3 nanocrystals embedded in PMMA: synthesis, structural characterization, and luminescent properties

    PubMed Central

    2013-01-01

    We report the formation of two-dimensional disordered arrays of poly(methyl)methacrylate (PMMA) microcolumns with embedded single size distribution of Lu0.990Er0.520Yb0.490 nanocrystals, (Er,Yb):Lu2O3, using a disordered porous silicon template. The cubic (Er,Yb):Lu2O3 nanocrystals, which crystallize into the cubic system with Ia3¯ space group, were synthesized using the modified Pechini method. Electronic microscopic techniques were used to study the distribution of the nanocrystals in the PMMA columns. Cathodoluminescence was used to observe the visible luminescence of the particles. Red emission attributed to 4 F9/2 → 4I15/2 erbium transition is predominant in these new composites. PMID:24034270

  2. Techniques for nonlinear optical characterization of materials: a review

    NASA Astrophysics Data System (ADS)

    de Araújo, Cid B.; Gomes, Anderson S. L.; Boudebs, Georges

    2016-03-01

    Various techniques to characterize the nonlinear (NL) optical response of centro-symmetric materials are presented and evaluated with emphasis on the relationship between the macroscopic measurable quantities and the microscopic properties of photonic materials. NL refraction and NL absorption of the materials are the phenomena of major interest. The dependence of the NL refraction and NL absorption coefficients on the nature of the materials was studied as well as on the laser excitation characteristics of wavelength, intensity, spatial profile, pulse duration and pulses repetition rate. Selected experimental results are discussed and illustrated. The various techniques currently available were compared and their relative advantages and drawbacks were evaluated. Critical comparisons among established techniques provided elements to evaluate their accuracies and sensitivities with respect to novel methods that present improvements with respect to the conventional techniques.

  3. Compression embedding

    DOEpatents

    Sandford, II, Maxwell T.; Handel, Theodore G.; Bradley, Jonathan N.

    1998-01-01

    A method and apparatus for embedding auxiliary information into the digital representation of host data created by a lossy compression technique and a method and apparatus for constructing auxiliary data from the correspondence between values in a digital key-pair table with integer index values existing in a representation of host data created by a lossy compression technique. The methods apply to data compressed with algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as ordered sequences of blocks containing integer indices having redundancy and uncertainty of value by one unit, allowing indices which are adjacent in value to be manipulated to encode auxiliary data. Also included is a method to improve the efficiency of lossy compression algorithms by embedding white noise into the integer indices. Lossy compression methods use loss-less compression to reduce to the final size the intermediate representation as indices. The efficiency of the loss-less compression, known also as entropy coding compression, is increased by manipulating the indices at the intermediate stage. Manipulation of the intermediate representation improves lossy compression performance by 1 to 10%.

  4. Compression embedding

    DOEpatents

    Sandford, M.T. II; Handel, T.G.; Bradley, J.N.

    1998-07-07

    A method and apparatus for embedding auxiliary information into the digital representation of host data created by a lossy compression technique and a method and apparatus for constructing auxiliary data from the correspondence between values in a digital key-pair table with integer index values existing in a representation of host data created by a lossy compression technique are disclosed. The methods apply to data compressed with algorithms based on series expansion, quantization to a finite number of symbols, and entropy coding. Lossy compression methods represent the original data as ordered sequences of blocks containing integer indices having redundancy and uncertainty of value by one unit, allowing indices which are adjacent in value to be manipulated to encode auxiliary data. Also included is a method to improve the efficiency of lossy compression algorithms by embedding white noise into the integer indices. Lossy compression methods use loss-less compression to reduce to the final size the intermediate representation as indices. The efficiency of the loss-less compression, known also as entropy coding compression, is increased by manipulating the indices at the intermediate stage. Manipulation of the intermediate representation improves lossy compression performance by 1 to 10%. 21 figs.

  5. Materials characterization in petroleum pipeline using Compton Scattering technique

    NASA Astrophysics Data System (ADS)

    Gouveia, M. A. G.; Lopes, R. T.; de Jesus, E. F. O.; Camerini, C. S.

    2003-06-01

    In this paper Compton Scattering technique is analyzed as a possible tool for the characterization of materials inside draining petroleum pipelines. The study was accomplished in laboratory scale, so the results should be analyzed to conclude if the system could be used in the field. The system used was composed of two detectors aligned by a Ce-137 source forming an angle of 90° with the detectors line (662 keV—direct beam, and 288 keV—scattered beam). The results obtained show the capability of the system for the characterization of materials like sand, paraffin and water inside pipelines.

  6. Preparation and characterization of mesh membranes using electrospinning technique

    NASA Astrophysics Data System (ADS)

    Russo, Giuseppina; Peters, Gerrit W. M.; Solberg, Ramon H. M.

    2012-07-01

    This paper is focused on the formulation and characterization of membranes that can act as biomedical devices with a mesh sample structure to reduce local inflammation and improve the tissue regeneration. These systems were realized homogenously dispersing lamellar Hydrotalcite loaded with Diclofenac Sodium (HTLc-DIK) in a polymeric matrix of Poly-caprolactone (PCL). Membranes were obtained through the electrospinning technique that has shown many advantages with respect to other techniques. Experiments carried out on the manufactured samples highlight the no- toxicity of the samples and very good interactions between cells and device.

  7. Phase-modulated beams technique for thin photorefractive films characterization

    NASA Astrophysics Data System (ADS)

    Barmenkov, Yu. O.; Kir'yanov, A. V.; Starodumov, A. N.; Kozhevnikov, N. M.; Lemmetyinen, H.

    2000-04-01

    The phase-modulated beams technique is developed for nonlinear thin photorefractive films characterization. In the Raman-Nath diffraction approximation, the formulas are deduced, allowing us to measure the amplitude of phase grating recorded in a film and its nonlinear refractive index n2. The method is applied for studying Langmuir-Blodgett multilayer thin (˜0.6 μm) films of Bacteriorhodopsin at wavelength 633 nm.

  8. Vadose Zone Characterization Techniques Developed by EMSP Research

    SciTech Connect

    Guillen, Donna P.

    2003-02-24

    This paper discusses research contributions made by Environmental Management Science Program (EMSP) research in the area of geophysical characterization of the subsurface. The goal of these EMSP research projects is to develop combined high-resolution measurement and interpretation packages that provide accurate, timely information needed to characterize the vadose zone. Various types of geophysical imaging techniques can be used to characterize the shallow subsurface. Since individual geophysical characterization tools all have specific limitations, many different techniques are being explored to provide more widespread applicability over a range of hydrogeologic settings. A combination of laboratory, field, theoretical, and computational studies are necessary to develop our understanding of how contaminants move through the vadose zone. This entails field tests with field-hardened systems, packaging and calibration of instrumentation, data processing and analysis algorithms, forward and inverse modeling, and so forth. DOE sites are seeking to team with EMSP researchers to leverage the basic science research investment and apply these advances to address subsurface contamination issues that plague many U.S. Department of Energy (DOE) sites.

  9. Characterization of European sword blades through neutron imaging techniques

    NASA Astrophysics Data System (ADS)

    Salvemini, F.; Grazzi, F.; Peetermans, S.; Gener, M.; Lehmann, E. H.; Zoppi, M.

    2014-09-01

    In the present work, we have studied two European rapier blades, dating back to the period ranging from the Late Renaissance to the Early Modern Age (about 17th to 18th century). In order to determine variation in quality and differences in technology, a study was undertaken with the purpose to observe variations in the blade microstructure (and consequently in the construction processes). The samples, which in the present case were expendable, have been investigated, preliminarily, through standard metallography and then by means of white beam and energy-selective neutron imaging. The comparison of the results, using the two techniques, turned out to be satisfactory, with a substantial quantitative agreement of the results obtained with the two techniques, and show the complementarity of the two methods. Metallography has been considered up to now the method of choice for metal material characterization. The correspondence between the two methods, as well as the non-invasive character of the neutron-based techniques and its possibility to obtain 3D reconstruction, candidate neutron imaging as an important and quantitatively reliable technique for metal characterization.

  10. Characterization of patinas by means of microscopic techniques

    SciTech Connect

    Vazquez-Calvo, C.

    2007-11-15

    Many stone-made historic buildings have a yellowish layer called 'patina' on their external surface. In some cases, it is due to the natural ageing of the stone caused by chemical-physical reactions between the surface of the stone and the environment, and in other cases it is the result of biological activity. The origin of these patinas can be also be due to ancient protective treatments. The use of organic additives, such as protein-based compounds, in lime or gypsum-based patinas is a traditional technique, which has been used in past centuries for the conservation and protection of stone materials. The thinness of the patinas ensures that microscopic techniques are irreplaceable for their analysis. Optical Microscopy, Fluorescence Microscopy, Scanning Electron Microscopy together with an Energy Dispersive X-ray Spectrometer, and Electron Microprobe are the microscopic techniques used for the characterization of these coverings, providing very useful information on their composition, texture and structure.

  11. Characterization of burns using hyperspectral imaging technique - a preliminary study.

    PubMed

    Calin, Mihaela Antonina; Parasca, Sorin Viorel; Savastru, Roxana; Manea, Dragos

    2015-02-01

    Surgical burn treatment depends on accurate estimation of burn depth. Many methods have been used to asses burns, but none has gained wide acceptance. Hyperspectral imaging technique has recently entered the medical research field with encouraging results. In this paper we present a preliminary study (case presentation) that aims to point out the value of this optical method in burn wound characterization and to set up future lines of investigation. A hyperspectral image of a leg and foot with partial thickness burns was obtained in the fifth postburn day. The image was analyzed using linear spectral unmixing model as a tool for mapping the investigated areas. The article gives details on the mathematical bases of the interpretation model and correlations with clinical examination pointing out the advantages of hyperspectral imaging technique. While the results were encouraging, further more extended and better founded studies are being prepared before recognizing hyperspectral imaging technique as an applicable method of burn wound assessment. PMID:24997530

  12. Electrical characterization of a Mapham inverter using pulse testing techniques

    NASA Technical Reports Server (NTRS)

    Baumann, E. D.; Myers, I. T.; Hammond, A. N.

    1990-01-01

    Electric power requirements for aerospace missions have reached megawatt power levels. Within the next few decades, it is anticipated that a manned lunar base, interplanetary travel, and surface exploration of the Martian surface will become reality. Several research and development projects aimed at demonstrating megawatt power level converters for space applications are currently underway at the NASA Lewis Research Center. Innovative testing techniques will be required to evaluate the components and converters, when developed, at their rated power in the absence of costly power sources, loads, and cooling systems. Facilities capable of testing these components and systems at full power are available, but their use may be cost prohibitive. The use of a multiple pulse testing technique is proposed to determine the electrical characteristics of large megawatt level power systems. Characterization of a Mapham inverter is made using the proposed technique and conclusions are drawn concerning its suitability as an experimental tool to evaluate megawatt level power systems.

  13. Synthesis and characterization of nano Cdo/NiO, nano Ag/ZnO composites & Ag/Zno embedded polymer nanocomposites

    NASA Astrophysics Data System (ADS)

    Godasu, Rahul

    Nanoparticles are finest structures whose size composition is within nanometer range. Thus nanoparticles are a collection of atoms bonded together with structural radius less than 100 nm. Nanocomposites are multiphase solid materials where one of the phases has one, two or three dimensions of less than 100 mn. Nano composites are prepared to improve mechanical, electrical, thermal, optical, electrochemical, catalytic properties from its parent materials. For instance, blend of nanoparticles with a polymer are called polymer nanocomposites. Nanostructured composites like Cadmium oxide/Nickel oxide (CdO/NiO) and silver/zinc oxide (Ag/ZnO) were prepared. Characterization of these prepared nanocomposites were carried out using X-ray powder diffraction, Differential scanning calorimetry, Scanning electron microscopy and the average sizes were determined using zeta sizer. Results obtained using characterization methods were in agreement stating that we were successful in synthesizing composites. The prepared Ag/ZnO nano composite was embedded in PCL polymer and we made films of PCL embedded with nano composite. The SEM image of the 5% Ag/ZnO embedded film clearly shows two regions, which indicates that Ag/ZnO nano composite was successfully embedded into the polymer using a non insitu method. SEM results also showed that the Zinc Oxide nano particles were successfully embedded into the polymer .

  14. Application of physical and chemical characterization techniques to metallic powders

    SciTech Connect

    Slotwinski, J. A.; Watson, S. S.; Stutzman, P. E.; Ferraris, C. F.; Peltz, M. A.; Garboczi, E. J.

    2014-02-18

    Systematic studies have been carried out on two different powder materials used for additive manufacturing: stainless steel and cobalt-chrome. The characterization of these powders is important in NIST efforts to develop appropriate measurements and standards for additive materials and to document the property of powders used in a NIST-led additive manufacturing material round robin. An extensive array of characterization techniques was applied to these two powders, in both virgin and recycled states. The physical techniques included laser diffraction particle size analysis, X-ray computed tomography for size and shape analysis, and optical and scanning electron microscopy. Techniques sensitive to chemistry, including X-ray diffraction and energy dispersive analytical X-ray analysis using the X-rays generated during scanning electron microscopy, were also employed. Results of these analyses will be used to shed light on the question: how does virgin powder change after being exposed to and recycled from one or more additive manufacturing build cycles? In addition, these findings can give insight into the actual additive manufacturing process.

  15. Automated wind load characterization of wind turbine structures by embedded model updating

    NASA Astrophysics Data System (ADS)

    Swartz, R. Andrew; Zimmerman, Andrew T.; Lynch, Jerome P.

    2010-04-01

    The continued development of renewable energy resources is for the nation to limit its carbon footprint and to enjoy independence in energy production. Key to that effort are reliable generators of renewable energy sources that are economically competitive with legacy sources. In the area of wind energy, a major contributor to the cost of implementation is large uncertainty regarding the condition of wind turbines in the field due to lack of information about loading, dynamic response, and fatigue life of the structure expended. Under favorable circumstances, this uncertainty leads to overly conservative designs and maintenance schedules. Under unfavorable circumstances, it leads to inadequate maintenance schedules, damage to electrical systems, or even structural failure. Low-cost wireless sensors can provide more certainty for stakeholders by measuring the dynamic response of the structure to loading, estimating the fatigue state of the structure, and extracting loading information from the structural response without the need of an upwind instrumentation tower. This study presents a method for using wireless sensor networks to estimate the spectral properties of a wind turbine tower loading based on its measured response and some rudimentary knowledge of its structure. Structural parameters are estimated via model-updating in the frequency domain to produce an identification of the system. The updated structural model and the measured output spectra are then used to estimate the input spectra. Laboratory results are presented indicating accurate load characterization.

  16. Synthesis of nano titania particles embedded in mesoporous SBA-15: characterization and photocatalytic activity.

    PubMed

    Yang, Jun; Zhang, Jun; Zhu, Liwei; Chen, Shaoyuan; Zhang, Yuanming; Tang, Yu; Zhu, Yulei; Li, Yongwang

    2006-09-21

    Supported nanocrystalline titanium dioxide (TiO2) has been prepared by a post-synthesis step via Ti-alkoxide hydrolysis through the use of mesoporous SBA-15 silica. TiO2/SBA-15 composites with various TiO2 loading have been prepared and characterized by X-ray diffraction, nitrogen adsorption, Fourier transform infrared spectroscopy and diffusive reflective UV-vis spectroscopy. The addition of mesoporous SBA-15 prevents the anatase to rutile phase transformation and the growth of crystal grain. TiO2 did not block the SBA-15 pores, and their surface was fully accessible for nitrogen adsorption. Calcination in air of the composites up to 800 degrees C did not change the nanocrystal phase and slightly increased the domain size from 5.0 to 7.5 nm, indicating that the anatase TiO2 grains in the mesostructures have a relatively high thermal stability and proper pore diameter allows controlling the size of obtained titania particles. The TiO2/SBA-15 composites prepared by this study showed much higher photodegradation ability for methylene blue (MB) than commercial pure TiO2 nanoparticles P-25. Experimental results indicate that the photocatalytic activity of titania/silica mixed materials depends on the adsorption ability of composite and the photocatalytic activity of the titania, and there is an optimal ratio of Ti:Si, too high or low Ti:Si ratio will lower the photodegradation ability of the composites. PMID:16621269

  17. Fluorescent techniques for discovery and characterization of phosphopantetheinyl transferase inhibitors

    PubMed Central

    Kosa, Nicolas M.; Foley, Timothy L.; Burkart, Michael D.

    2016-01-01

    Phosphopantetheinyl transferase (E.C. 2.7.8.-) activates biosynthetic pathways that synthesize both primary and secondary metabolites in bacteria. Inhibitors of these enzymes have the potential to serve as antibiotic compounds that function through a unique mode of action and possess clinical utility. Here we report a direct and continuous assay for this enzyme class based upon monitoring polarization of a fluorescent phosphopantetheine analog as it is transferred from a low molecular weight coenzyme A substrate to higher molecular weight protein acceptor. We demonstrate the utility of this method for the biochemical characterization of phosphopantetheinyl transferase Sfp, a canonical representative from this class. We also establish the portability of this technique to other homologs by adapting the assay to function with the human phosphopantetheinyl transferase, a target for which a microplate detection method does not currently exist. Comparison of these targets provides a basis to predict therapeutic index of inhibitor candidates and offers a valuable characterization of enzyme activity. PMID:24192555

  18. Exploring Characterizations of Learning Object Repositories Using Data Mining Techniques

    NASA Astrophysics Data System (ADS)

    Segura, Alejandra; Vidal, Christian; Menendez, Victor; Zapata, Alfredo; Prieto, Manuel

    Learning object repositories provide a platform for the sharing of Web-based educational resources. As these repositories evolve independently, it is difficult for users to have a clear picture of the kind of contents they give access to. Metadata can be used to automatically extract a characterization of these resources by using machine learning techniques. This paper presents an exploratory study carried out in the contents of four public repositories that uses clustering and association rule mining algorithms to extract characterizations of repository contents. The results of the analysis include potential relationships between different attributes of learning objects that may be useful to gain an understanding of the kind of resources available and eventually develop search mechanisms that consider repository descriptions as a criteria in federated search.

  19. Synthesis, characterization, structural, and optical properties of zinc oxide nanostructures embedded in silicon based substrates

    NASA Astrophysics Data System (ADS)

    Pandey, Bimal

    Structural and optical properties of ZnO nanostructures synthesized by low energy ion implantation technique were examined. ZnO molecular ions were implanted into Si/SiO2 substrates at room temperature and then furnace annealed under different temperatures and environments. In all as-implanted samples only Zn nanostructures with varying diameters distributed into the Si/SiO2 matrices were observed. No trace of ZnO was found. The distributions of Zn nanostructures in Si/SiO2 closely matched results from Stopping and Range of Ions in Matter (SRIM) simulations. During annealing at 750 °C, Zn diffused both toward and away from the surface of the substrate and combine with oxygen to form ZnO nanostructures. At higher annealing temperatures ZnO bonding started to break down and transfer to zinc silicate (Zn2SiO4), and at 900 °C the ZnO was completely converted into Zn2SiO4. The average sizes of Zn/ZnO nanostructures depended on the ion fluence. If the fluence increased the average sizes of nanostructures also increased and vice versa. For room temperature photoluminescence (RT-PL), band-edge emission in the ultraviolet (UV) region was observed from all samples annealed at 700 °C/750 °C and were slightly blue shifted as compare to bulk ZnO. Donor-bound exciton (D,X) and acceptor-bound exciton (A,X) transitions were observed in low temperature photoluminescence (PL). The lifetime of both donor-bound excitonic emission (D, X) and acceptor-bound excitonic emission (A, X) were found to be in the picosecond (ps) range.

  20. A High-speed Characterization Technique for Solar Silicon

    NASA Technical Reports Server (NTRS)

    Lehmann, V.; Foell, H.; Bernewitz, L.; Grabmaier, J. G.

    1984-01-01

    High-speed crystal growth techniques demand high-speed characterization techniques to allow a timely feed-back of information to the crystal growers. The unique properties of the Si electrolyte-contact (SEC) provide for an extremely fast and simple measurement of the light-induced photo-current for any piece of Si without lengthy preparation of the specimen. Electropolishing at high anodic current densities allows for insitu generation of fresh surfaces whereas preferential etching of defects in various modes is possible at low current densities. In n-type Si a simple estimation of the minority-carrier diffusion length is possible in many cases. Laser-scanning enables local probing of the photocurrent and provides data about the homogeneity of a sample. The experimental realization of the method is described in detail and examples are given and discussed.

  1. Characterization of PTFE Using Advanced Thermal Analysis Techniques

    NASA Astrophysics Data System (ADS)

    Blumm, J.; Lindemann, A.; Meyer, M.; Strasser, C.

    2010-10-01

    Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer used in numerous industrial applications. It is often referred to by its trademark name, Teflon. Thermal characterization of a PTFE material was carried out using various thermal analysis and thermophysical properties test techniques. The transformation energetics and specific heat were measured employing differential scanning calorimetry. The thermal expansion and the density changes were determined employing pushrod dilatometry. The viscoelastic properties (storage and loss modulus) were analyzed using dynamic mechanical analysis. The thermal diffusivity was measured using the laser flash technique. Combining thermal diffusivity data with specific heat and density allows calculation of the thermal conductivity of the polymer. Measurements were carried out from - 125 °C up to 150 °C. Additionally, measurements of the mechanical properties were carried out down to - 170 °C. The specific heat tests were conducted into the fully molten regions up to 370 °C.

  2. Characterizing TPS Microstructure: A Review of Some techniques

    NASA Technical Reports Server (NTRS)

    Gasch, Matthew; Stackpole, Mairead; Agrawal, Parul; Chavez-Garcie, Jose

    2011-01-01

    I. When seeking to understand ablator microstructure and morphology there are several useful techniques A. SEM 1) Visual characteriza3on at various length scales. 2) Chemical mapping by backscatter or x-ray highlights areas of interest. 3) Combined with other techniques (density, weight change, chemical analysis) SEM is a powerful tool to aid in explaining thermo/structural data. B. ASAP. 1) Chemical characteriza3on at various length scales. 2) Chemical mapping of pore structure by gas adsorption. 3) Provides a map of pore size vs. pore volume. 4) Provided surface area of exposed TPS. II. Both methods help characterize and understand how ablators react with other chemical species and provides insight into how they oxidize.

  3. Experimental techniques in ultrasonics for NDE and material characterization

    NASA Astrophysics Data System (ADS)

    Tittmann, B. R.

    A development status evaluation is presented for ultrasonics NDE characterization of aerospace alloys and composites in such application as the Space Shuttle, Space Station Freedom, and hypersonic aircraft. The use of such NDE techniques extends to composite-cure monitoring, postmanufacturing quality assurance, and in-space service inspection of such materials as graphite/epoxy, Ti alloys, and Al honeycomb. Attention is here given to the spectroscopy of elastically scattered wave pulses from flaws, the acoustical imaging of flaws in honeycomb structures, and laser-based ultrasonics for the noncontact inspection of composite structures.

  4. Modulation Z-scan technique for characterization of photorefractive crystals

    NASA Astrophysics Data System (ADS)

    Aguilar, P. A. Marquez; Sanchez-Mondragon, J. J.; Stepanov, S.

    1996-10-01

    We propose a simple single-beam configuration for characterization of the amplitude, speed of growth, and polarization properties of the photoinduced refractive-index change that is due to a drift photorefractive mechanism of nonlinearity in crystals, namely, the modulation Z-scan technique, based on the modulation of an externally applied electric field. The results of a simple theoretical model developed for one-dimensional parabolic photorefractive lens formation in this configuration are illustrated by original experiments with a semi-insulating GaAs crystal at lambda =1.06 mu m .

  5. Characterization of Cavities Using the GPR, LIDAR and GNSS Techniques

    NASA Astrophysics Data System (ADS)

    Conejo-Martín, Miguel Angel; Herrero-Tejedor, Tomás Ramón; Lapazaran, Javier; Perez-Martin, Enrique; Otero, Jaime; Prieto, Juan F.; Velasco, Jesús

    2015-11-01

    The study of the many types of natural and manmade cavities in different parts of the world is important to the fields of geology, geophysics, engineering, architectures, agriculture, heritages and landscape. Ground-penetrating radar (GPR) is a noninvasive geodetection and geolocation technique suitable for accurately determining buried structures. This technique requires knowing the propagation velocity of electromagnetic waves (EM velocity) in the medium. We propose a method for calibrating the EM velocity using the integration of laser imaging detection and ranging (LIDAR) and GPR techniques using the Global Navigation Satellite System (GNSS) as support for geolocation. Once the EM velocity is known and the GPR profiles have been properly processed and migrated, they will also show the hidden cavities and the old hidden structures from the cellar. In this article, we present a complete study of the joint use of the GPR, LIDAR and GNSS techniques in the characterization of cavities. We apply this methodology to study underground cavities in a group of wine cellars located in Atauta (Soria, Spain). The results serve to identify construction elements that form the cavity and group of cavities or cellars. The described methodology could be applied to other shallow underground structures with surface connection, where LIDAR and GPR profiles could be joined, as, for example, in archaeological cavities, sewerage systems, drainpipes, etc.

  6. A technique for embedding undecalcified bone samples for detecting alpha-emitters using vacuum impregnation with Spurr's resin.

    PubMed

    Haines, J W

    1992-01-01

    A method has been developed by which large samples of mineralized bone, containing an alpha-emitter, can be embedded in Spurr's resin in a fraction of the time required by conventional methods. Bone samples were freeze-dried or fixed and dried prior to impregnation with Spurr's resin under vacuum. Sections were cut for the preparation of either alpha-track or fission-track autoradiographs using the solid state detector CR-39. This method is applicable to samples containing a mobile form of a radionuclide that may be translocated during the processes of fixation and dehydration of the specimen. PMID:1377500

  7. Application of linear graph embedding as a dimensionality reduction technique and sparse representation classifier as a post classifier for the classification of epilepsy risk levels from EEG signals

    NASA Astrophysics Data System (ADS)

    Prabhakar, Sunil Kumar; Rajaguru, Harikumar

    2015-12-01

    The most common and frequently occurring neurological disorder is epilepsy and the main method useful for the diagnosis of epilepsy is electroencephalogram (EEG) signal analysis. Due to the length of EEG recordings, EEG signal analysis method is quite time-consuming when it is processed manually by an expert. This paper proposes the application of Linear Graph Embedding (LGE) concept as a dimensionality reduction technique for processing the epileptic encephalographic signals and then it is classified using Sparse Representation Classifiers (SRC). SRC is used to analyze the classification of epilepsy risk levels from EEG signals and the parameters such as Sensitivity, Specificity, Time Delay, Quality Value, Performance Index and Accuracy are analyzed.

  8. Karst characterization in a semi-arid region using gravity, seismic, and resistivity geophysical techniques.

    SciTech Connect

    Barnhart, Kevin Scott

    2013-10-01

    We proposed to customize emerging in situ geophysical monitoring technology to generate time-series data during sporadic rain events in a semi-arid region. Electrodes were to be connected to wireless %5Cnodes%22 which can be left in the eld for many months. Embedded software would then increase sampling frequency during periods of rainfall. We hypothesized that this contrast between no-volume ow in karst passageways dur- ing dry periods and partial- or saturated-volume ow during a rain event is detectable by these Wireless Sensor Network (WSN) geophysical nodes, we call this a Wireless Resistivity Network (WRN). The development of new methodologies to characterize semi-arid karst hydrology is intended to augment Sandia National Laboratorys mission to lead e orts in energy technologies, waste disposal and climate security by helping to identify safe and secure regions and those that are at risk. Development and initial eld testing identi ed technological barriers to using WRNs for identifying semi-arid karst, exposing R&D which can be targeted in the future. Gravity, seismic, and resis- tivity surveys elucidated how each technique might e ectively be used to characterize semi-arid karst. This research brings to light the importance and challenges with char- acterizing semi-arid karst through a multi-method geophysical study. As there have been very few studies with this emphasis, this study has expanded the body of practical experience needed to protect the nations water and energy security interests.

  9. Advanced techniques for characterization of ion beam modified materials

    DOE PAGESBeta

    Zhang, Yanwen; Debelle, Aurélien; Boulle, Alexandre; Kluth, Patrick; Tuomisto, Filip

    2014-10-30

    Understanding the mechanisms of damage formation in materials irradiated with energetic ions is essential for the field of ion-beam materials modification and engineering. Utilizing incident ions, electrons, photons, and positrons, various analysis techniques, including Rutherford backscattering spectrometry (RBS), electron RBS, Raman spectroscopy, high-resolution X-ray diffraction, small-angle X-ray scattering, and positron annihilation spectroscopy, are routinely used or gaining increasing attention in characterizing ion beam modified materials. The distinctive information, recent developments, and some perspectives in these techniques are reviewed in this paper. Applications of these techniques are discussed to demonstrate their unique ability for studying ion-solid interactions and the corresponding radiationmore » effects in modified depths ranging from a few nm to a few tens of μm, and to provide information on electronic and atomic structure of the materials, defect configuration and concentration, as well as phase stability, amorphization and recrystallization processes. Finally, such knowledge contributes to our fundamental understanding over a wide range of extreme conditions essential for enhancing material performance and also for design and synthesis of new materials to address a broad variety of future energy applications.« less

  10. Advanced techniques for characterization of ion beam modified materials

    SciTech Connect

    Zhang, Yanwen; Debelle, Aurélien; Boulle, Alexandre; Kluth, Patrick; Tuomisto, Filip

    2014-10-30

    Understanding the mechanisms of damage formation in materials irradiated with energetic ions is essential for the field of ion-beam materials modification and engineering. Utilizing incident ions, electrons, photons, and positrons, various analysis techniques, including Rutherford backscattering spectrometry (RBS), electron RBS, Raman spectroscopy, high-resolution X-ray diffraction, small-angle X-ray scattering, and positron annihilation spectroscopy, are routinely used or gaining increasing attention in characterizing ion beam modified materials. The distinctive information, recent developments, and some perspectives in these techniques are reviewed in this paper. Applications of these techniques are discussed to demonstrate their unique ability for studying ion-solid interactions and the corresponding radiation effects in modified depths ranging from a few nm to a few tens of μm, and to provide information on electronic and atomic structure of the materials, defect configuration and concentration, as well as phase stability, amorphization and recrystallization processes. Finally, such knowledge contributes to our fundamental understanding over a wide range of extreme conditions essential for enhancing material performance and also for design and synthesis of new materials to address a broad variety of future energy applications.

  11. Technique for the estimation of surface temperatures from embedded temperature sensing for rapid, high energy surface deposition.

    SciTech Connect

    Watkins, Tyson R.; Schunk, Peter Randall; Roberts, Scott Alan

    2014-07-01

    Temperature histories on the surface of a body that has been subjected to a rapid, highenergy surface deposition process can be di cult to determine, especially if it is impossible to directly observe the surface or attach a temperature sensor to it. In this report, we explore two methods for estimating the temperature history of the surface through the use of a sensor embedded within the body very near to the surface. First, the maximum sensor temperature is directly correlated with the peak surface temperature. However, it is observed that the sensor data is both delayed in time and greatly attenuated in magnitude, making this approach unfeasible. Secondly, we propose an algorithm that involves tting the solution to a one-dimensional instantaneous energy solution problem to both the sensor data and to the results of a one-dimensional CVFEM code. This algorithm is shown to be able to estimate the surface temperature 20 C.

  12. Laser Shockwave Technique For Characterization Of Nuclear Fuel Plate Interfaces

    SciTech Connect

    James A. Smith; Barry H. Rabin; Mathieu Perton; Daniel Lévesque; Jean-Pierre Monchalin; Martin Lord

    2012-07-01

    The US National Nuclear Security Agency is tasked with minimizing the worldwide use of high-enriched uranium. One aspect of that effort is the conversion of research reactors to monolithic fuel plates of low-enriched uranium. The manufacturing process includes hot isostatic press bonding of an aluminum cladding to the fuel foil. The Laser Shockwave Technique (LST) is here evaluated for characterizing the interface strength of fuel plates using depleted Uranium/Mo foils. LST is a non-contact method that uses lasers for the generation and detection of large amplitude acoustic waves and is therefore well adapted to the quality assurance of this process. Preliminary results show a clear signature of well-bonded and debonded interfaces and the method is able to classify/rank the bond strength of fuel plates prepared under different HIP conditions.

  13. Laser shockwave technique for characterization of nuclear fuel plate interfaces

    SciTech Connect

    Perton, M.; Levesque, D.; Monchalin, J.-P.; Lord, M.; Smith, J. A.; Rabin, B. H.

    2013-01-25

    The US National Nuclear Security Agency is tasked with minimizing the worldwide use of high-enriched uranium. One aspect of that effort is the conversion of research reactors to monolithic fuel plates of low-enriched uranium. The manufacturing process includes hot isostatic press bonding of an aluminum cladding to the fuel foil. The Laser Shockwave Technique (LST) is here evaluated for characterizing the interface strength of fuel plates using depleted Uranium/Mo foils. LST is a non-contact method that uses lasers for the generation and detection of large amplitude acoustic waves and is therefore well adapted to the quality assurance of this process. Preliminary results show a clear signature of well-bonded and debonded interfaces and the method is able to classify/rank the bond strength of fuel plates prepared under different HIP conditions.

  14. Electrical Characterizations of Lightning Strike Protection Techniques for Composite Materials

    NASA Technical Reports Server (NTRS)

    Szatkowski, George N.; Nguyen, Truong X.; Koppen, Sandra V.; Ely, Jay J.; Mielnik, John J.

    2009-01-01

    The growing application of composite materials in commercial aircraft manufacturing has significantly increased the risk of aircraft damage from lightning strikes. Composite aircraft designs require new mitigation strategies and engineering practices to maintain the same level of safety and protection as achieved by conductive aluminum skinned aircraft. Researchers working under the NASA Aviation Safety Program s Integrated Vehicle Health Management (IVHM) Project are investigating lightning damage on composite materials to support the development of new mitigation, diagnosis & prognosis techniques to overcome the increased challenges associated with lightning protection on composite aircraft. This paper provides an overview of the electrical characterizations being performed to support IVHM lightning damage diagnosis research on composite materials at the NASA Langley Research Center.

  15. Characterization of Sorolla's gouache pigments by means of spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Roldán, Clodoaldo; Juanes, David; Ferrazza, Livio; Carballo, Jorgelina

    2016-02-01

    This paper presents the characterization of the Joaquín Sorolla's gouache sketches for the oil on canvas series "Vision of Spain" commissioned by A. M. Huntington to decorate the library of the Hispanic Society of America in New York. The analyses were focused on the identification of the elemental composition of the gouache pigments by means of portable EDXRF spectrometry in a non-destructive mode. Additionally, SEM-EDX and FTIR analyses of a selected set of micro-samples were carried out to identify completely the pigments, the paint technique and the binding media. The obtained results have confirmed the identification of lead and zinc white, vermillion, earth pigments, ochre, zinc yellow, chrome yellow, ultramarine, Prussian blue, chromium based and copper-arsenic based green pigments, bone black and carbon based black pigments, and the use of gum arabic as binding media in the gouache pigments.

  16. Therapy ultrasound equipment characterization: Comparison of three techniques.

    PubMed

    Gutierrez, M I; Leija, L; Vera, A

    2008-01-01

    Methods for characterizing ultrasonic therapy equipment rapidly and easily have to be implemented in order to avoid damages to patients; the existent methods measure different parameters in the ultrasonic beam that can be used to determine if the equipment works appropriately. In this paper, a comparison of three methods to characterize the ultrasonic beam is presented. The first one is a C-scan with microprobe which uses a hydrophone for measuring the signal and a positioning system. The second method is the IR-thermography which uses a phantom to absorb the ultrasonic energy and to convert it into heat. Here, the heat distribution is obtained with an IR camera. The third method uses a sheet of thermochromic liquid crystals (TLC) as sensor and a phantom to absorb the energy. The heat distribution is obtained with a normal camera because the TLCs change their color as a function of temperature. The results indicate that each technique has its own benefits, but the most important parameters can be obtained with only one of them. PMID:19163868

  17. Eddy current techniques for super duplex stainless steel characterization

    NASA Astrophysics Data System (ADS)

    Camerini, C.; Sacramento, R.; Areiza, M. C.; Rocha, A.; Santos, R.; Rebello, J. M.; Pereira, G.

    2015-08-01

    Super duplex stainless steel (SDSS) is a two-phase material where the microstructure consists of grains of ferrite (δ) and austenite (γ). SDSS exhibit an attractive combination of properties, such as: strength, toughness and stress corrosion cracking resistance. Nevertheless, SDSS attain these properties after a controlled solution heat treatment, leading to a similar volumetric fraction of δ and γ. Any further heat treatment, welding operation for example, can change the balance of the original phases, or may also lead to precipitation of a deleterious phase, such as sigma (σ). For these situations, the material corrosion resistance is severely impaired. In the present study, several SDSS samples with low σ phase content and non-balanced microstructure were intentionally obtained by thermally treating SDSS specimens. Electromagnetic techniques, conventional Eddy Current Testing (ECT) and Saturated Low Frequency Eddy Current (SLOFEC), were employed to characterize the SDSS samples. The results showed that ECT and SLOFEC are reliable techniques to evaluate σ phase presence in SDSS and can provide an estimation of the δ content.

  18. Note: A non-invasive electronic measurement technique to measure the embedded four resistive elements in a Wheatstone bridge sensor

    SciTech Connect

    Ravelo Arias, S. I.; Ramírez Muñoz, D.; Ferreira, R.; Freitas, P.

    2015-06-15

    The work shows a measurement technique to obtain the correct value of the four elements in a resistive Wheatstone bridge without the need to separate the physical connections existing between them. Two electronic solutions are presented, based on a source-and-measure unit and using discrete electronic components. The proposed technique brings the possibility to know the mismatching or the tolerance between the bridge resistive elements and then to pass or reject it in terms of its related common-mode rejection. Experimental results were taken in various Wheatstone resistive bridges (discrete and magnetoresistive integrated bridges) validating the proposed measurement technique specially when the bridge is micro-fabricated and there is no physical way to separate one resistive element from the others.

  19. Note: A non-invasive electronic measurement technique to measure the embedded four resistive elements in a Wheatstone bridge sensor

    NASA Astrophysics Data System (ADS)

    Ravelo Arias, S. I.; Ramírez Muñoz, D.; Cardoso, S.; Ferreira, R.; Freitas, P.

    2015-06-01

    The work shows a measurement technique to obtain the correct value of the four elements in a resistive Wheatstone bridge without the need to separate the physical connections existing between them. Two electronic solutions are presented, based on a source-and-measure unit and using discrete electronic components. The proposed technique brings the possibility to know the mismatching or the tolerance between the bridge resistive elements and then to pass or reject it in terms of its related common-mode rejection. Experimental results were taken in various Wheatstone resistive bridges (discrete and magnetoresistive integrated bridges) validating the proposed measurement technique specially when the bridge is micro-fabricated and there is no physical way to separate one resistive element from the others.

  20. Characterization and cytocompatibility of thermosensitive hydrogel embedded with chitosan nanoparticles for delivery of bone morphogenetic protein-2 plasmid DNA.

    PubMed

    Li, Dan-Dan; Pan, Jian-Feng; Ji, Qiu-Xia; Yu, Xin-Bo; Liu, Ling-Shuang; Li, Hui; Jiao, Xiao-Ju; Wang, Lei

    2016-08-01

    A novel injectable chitosan thermosensitive hydrogel was designed as a target multi-effect scaffold for endogenous repair of the periodontium. The hydrogel complex was designed by embedding chitosan nanoparticles (CSn) loaded with bone morphogenetic protein-2 plasmid DNA (pDNA-BMP2) into a chitosan (CS)-based hydrogel with α,β-glycerophosphate (α,β-GP), termed CS/CSn(pDNA-BMP2)-GP. Characterization, the in vitro release profile for pDNA-BMP2, and cytocompatibility to human periodontal ligament cells (HPDLCs), were then conducted. The average diameter of the CSn(pDNA-BMP2) was 270.1 nm with a polydispersity index (PDI) of 0.486 and zeta potential of +27.0 mv. A DNase I protection assay showed that CSn could protect the pDNA-BMP2 from nuclease degradation. Encapsulation efficiency and loading capacity of CSn(pDNA-BMP2) were more than 80 and 30 %, respectively. The sol-gel transition time was only 3 min when CSn(pDNA-BMP2) was added into the CS/α,β-GP system. Scanning electron microscopy showed that CSn(pDNA-BMP2) was randomly dispersed in a network with regular holes and a porous structure. Weighting method showed the swelling ratio and degradation was faster in medium of pH 4.0 than pH 6.8. An in vitro pDNA-BMP2 release test showed that the cumulative release rate of pDNA-BMP2 was much slower from CS/CSn-GP than from CSn in identical release media. In release media with different pH, pDNA-BMP2 release was much slower at pH 6.8 than at pH 4.0. Three-dimensional culture with HPDLCs showed good cell proliferation and the Cell-Counting Kit-8 assay indicated improved cell growth with the addition of CSn(pDNA-BMP2) to CS/α,β-GP. In summary, the CS/CSn(pDNA-BMP2)-GP complex system exhibited excellent biological properties and cytocompatibility, indicating great potential as a gene delivery carrier and tissue regeneration scaffold for endogenous repair of the periodontium. PMID:27405491

  1. Data embedding

    DOEpatents

    Sandford, M.T. II; Handel, T.G.

    1997-08-19

    A method is disclosed for embedding auxiliary information into a set of host data, such as a photograph, television signal, facsimile transmission, or identification card. All such host data contain intrinsic noise, allowing pixels in the host data which are nearly identical and which have values differing by less than the noise value to be manipulated and replaced with auxiliary data. As the embedding method does not change the elemental values of the host data, the auxiliary data do not noticeably affect the appearance or interpretation of the host data. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user. 19 figs.

  2. Data embedding

    DOEpatents

    Sandford, II, Maxwell T.; Handel, Theodore G.

    1997-01-01

    A method of embedding auxiliary information into a set of host data, such as a photograph, television signal, facsimile transmission, or identification card. All such host data contain intrinsic noise, allowing pixels in the host data which are nearly identical and which have values differing by less than the noise value to be manipulated and replaced with auxiliary data. As the embedding method does not change the elemental values of the host data, the auxiliary data do not noticeably affect the appearance or interpretation of the host data. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user.

  3. Thermal Characterization of Edible Oils by Using Photopyroelectric Technique

    NASA Astrophysics Data System (ADS)

    Lara-Hernández, G.; Suaste-Gómez, E.; Cruz-Orea, A.; Mendoza-Alvarez, J. G.; Sánchez-Sinéncio, F.; Valcárcel, J. P.; García-Quiroz, A.

    2013-05-01

    Thermal properties of several edible oils such as olive, sesame, and grape seed oils were obtained by using the photopyroelectric technique. The inverse photopyroelectric configuration was used in order to obtain the thermal effusivity of the oil samples. The theoretical equation for the photopyroelectric signal in this configuration, as a function of the incident light modulation frequency, was fitted to the experimental data in order to obtain the thermal effusivity of these samples. Also, the back photopyroelectric configuration was used to obtain the thermal diffusivity of these oils; this thermal parameter was obtained by fitting the theoretical equation for this configuration, as a function of the sample thickness (called the thermal wave resonator cavity), to the experimental data. All measurements were done at room temperature. A complete thermal characterization of these edible oils was achieved by the relationship between the obtained thermal diffusivities and thermal effusivities with their thermal conductivities and volumetric heat capacities. The obtained results are in agreement with the thermal properties reported for the case of the olive oil.

  4. Nanocrystalline materials: recent advances in crystallographic characterization techniques

    PubMed Central

    Ringe, Emilie

    2014-01-01

    Most properties of nanocrystalline materials are shape-dependent, providing their exquisite tunability in optical, mechanical, electronic and catalytic properties. An example of the former is localized surface plasmon resonance (LSPR), the coherent oscillation of conduction electrons in metals that can be excited by the electric field of light; this resonance frequency is highly dependent on both the size and shape of a nanocrystal. An example of the latter is the marked difference in catalytic activity observed for different Pd nanoparticles. Such examples highlight the importance of particle shape in nanocrystalline materials and their practical applications. However, one may ask ‘how are nanoshapes created?’, ‘how does the shape relate to the atomic packing and crystallography of the material?’, ‘how can we control and characterize the external shape and crystal structure of such small nanocrystals?’. This feature article aims to give the reader an overview of important techniques, concepts and recent advances related to these questions. Nucleation, growth and how seed crystallography influences the final synthesis product are discussed, followed by shape prediction models based on seed crystallography and thermodynamic or kinetic parameters. The crystallographic implications of epitaxy and orientation in multilayered, core-shell nanoparticles are overviewed, and, finally, the development and implications of novel, spatially resolved analysis tools are discussed. PMID:25485133

  5. Photogrammetric detection technique for rotor blades structural characterization

    NASA Astrophysics Data System (ADS)

    Enei, C.; Bernardini, G.; Serafini, J.; Mattioni, L.; Ficuciello, C.; Vezzari, V.

    2015-11-01

    This paper describes an innovative use of photogrammetric detection techniques to experimentally estimate structural/inertial properties of helicopter rotor blades. The identification algorithms for the evaluation of mass and flexural stiffness distributions are an extension of the ones proposed by Larsen, whereas the procedure for torsional properties determination (stiffness and shear center position) is based on the Euler-Prandtl beam theory. These algorithms rely on measurements performed through photogrammetric detection, which requires the collection of digital photos allowing the identification of 3D coordinates of labeled points (markers) on the structure through the correlation of 2D pictures. The displacements are evaluated by comparing the positions of markers in loaded and reference configuration. Being the applied loads known, the structural characteristics can be directly obtained from the measured displacements. The accuracy of the proposed identification algorithms has been firstly verified by comparison with numerical and experimental data, and then applied to the structural characterization of two main rotor blades, designed for ultra-light helicopter applications.

  6. Characterization of Lavandula spp. Honey Using Multivariate Techniques.

    PubMed

    Estevinho, Leticia M; Chambó, Emerson Dechechi; Pereira, Ana Paula Rodrigues; Carvalho, Carlos Alfredo Lopes de; Toledo, Vagner de Alencar Arnaut de

    2016-01-01

    Traditionally, melissopalynological and physicochemical analyses have been the most used to determine the botanical origin of honey. However, when performed individually, these analyses may provide less unambiguous results, making it difficult to discriminate between mono and multifloral honeys. In this context, with the aim of better characterizing this beehive product, a selection of 112 Lavandula spp. monofloral honey samples from several regions were evaluated by association of multivariate statistical techniques with physicochemical, melissopalynological and phenolic compounds analysis. All honey samples fulfilled the quality standards recommended by international legislation, except regarding sucrose content and diastase activity. The content of sucrose and the percentage of Lavandula spp. pollen have a strong positive association. In fact, it was found that higher amounts of sucrose in honey are related with highest percentage of pollen of Lavandula spp.. The samples were very similar for most of the physicochemical parameters, except for proline, flavonoids and phenols (bioactive factors). Concerning the pollen spectrum, the variation of Lavandula spp. pollen percentage in honey had little contribution to the formation of samples groups. The formation of two groups regarding the physicochemical parameters suggests that the presence of other pollen types in small percentages influences the factor termed as "bioactive", which has been linked to diverse beneficial health effects. PMID:27588420

  7. STATE-OF-THE-ART FIELD TECHNIQUES FOR SITE CHARACTERIZATION

    EPA Science Inventory

    Many of the traditional methods for characterizing the hydrogeologic properties and contaminant distribution of subsurface materials were derived from methods developed in the water supply industry. These methods generally result in the characterization of bulk aquifer propert...

  8. Detection and characterization of Newcastle disease virus in formalin-fixed, paraffin-embedded tissues from commercial broilers in Egypt.

    PubMed

    Abdel-Glil, Mostafa Y; Mor, Sunil K; Sharafeldin, Tamer A; Porter, Robert E; Goyal, Sagar M

    2014-03-01

    Newcastle disease (ND) is highly contagious and causes severe economic losses to the poultry industry due to high morbidity and mortality. In this report, we describe the detection of Newcastle disease virus (NDV) in formalin-fixed tissues from an outbreak of ND on broiler farms in Egypt. The affected birds experienced respiratory and/or nervous signs and a 75% mortality rate. Tissue samples were collected and placed in 10% neutral buffered formalin followed by embedding in paraffin. RNA was extracted from 80-microm formalin-fixed paraffin-embedded tissue blocks and recovered in 60 microl of elution buffer. All samples were negative for influenza virus by real-time reverse-transcription (RT)-PCR but positive for NDV. These flocks were known to have been vaccinated with a live NDV vaccine (LaSota strain). The nucleic acid sequences of the virus detected in this study were similar to those of a velogenic virus at its cleavage site 111GRRQKR*F117 and clustered with class II genogroup VII lineage of NDV, with a nucleotide sequence identity of 94%-99%. Although extraction and amplification of NDV from paraffin-embedded tissues from experimentally infected birds has been reported previously, this study reports on the use of RT-PCR on formalin-fixed tissues from actual field samples. PMID:24758123

  9. Characterization of soil behavior using electromagnetic wave-based technique

    NASA Astrophysics Data System (ADS)

    Dong, Xiaobo

    samples so that the beta value, i.e., the ratio between the conductivities of the sediment and the fluid, is smaller than 1. The beta value is greater than 1 in the Group B samples owing to an overcompensation of surface conduction. Sedimentation behavior of two kaolinite samples with distinct fabric associations is characterized using mechanical and electromagnetic wave-based techniques. The two different fabric formations, the edge-to-face (EF) flocculated structure (i.e., sample A) and the dispersed and deflocculated structure (i.e., sample B), were regulated by changing the pH of the pore fluid and are produced. The anisotropy of shear wave velocity and DC conductivity was not observed in the sediment of sample A because of EF isotropic fabric associations but it was detected in sample B as a result of face-to-face (FF) aggregation. An open card-house structure of the sample A sediment results in a higher relaxation strength of the bulk water, Deltakappaw owing to a higher water content; the smaller Deltakappaw measured in the sample B sediment indicates denser packing. In both samples, sediment consolidation gives rise to a decrease in the bulk-water relaxation strength but an increase in the bound-water relaxation strength owing to increasing particle content. In response to sediment consolidation, the sediment conductivity of sample A continuously decreases because of the reduced contribution from the fluid conductivity. In sample B, the surface conduction via the overlapped double layer overcompensates such a decreased contribution so that the sediment conductivity increases with increasing particle content. The slim-form open-ended coaxial probe is also used to conduct a local dielectric measurement. The measured results, i.e. dielectric relaxation strength of bulk water, Deltakappaw, and the DC conductivity of the saturated sample, sigmamix, are jointly used to characterize the spatial variability of different specimens including glass beads, sand and mica

  10. Characterizing Subglacial Interfaces With Airborne Radar Sounding Techniques

    NASA Astrophysics Data System (ADS)

    Peters, M. E.; Blankenship, D. D.; Morse, D. L.

    2004-12-01

    Ice sheets are sensitive indicators of global change including sea-level rise. An ice sheet's subglacial interface is an important factor controlling its dynamic behavior. In particular, the grounding zones of ice streams and subglacial lakes are complex systems involving the interaction of the moving ice mass with underlying materials such as liquid water, saturated lubricating tills, and rough or frozen bedrock sticky spots. Imaging and characterizing the subglacial environment of ice sheets is fundamental to understanding these complex systems. Airborne radar sounding is a powerful and well-known technique for studying ice sheets and glaciers and their contiguous underlying environments. We present results from data acquired in 2001 over the ice stream C grounding zone in West Antarctica, as well as over a hypothesized subglacial lake near the South Pole. These data were acquired using a uniquely configured coherent airborne radar system. Our focus has been to characterize the subglacial interface through radar echo analysis based on reflection and scattering theory. The radar system uses a programmable signal source linked to a 10 kW transmitter and a dual-channel coherent down-conversion receiver. The radar operates in chirped pulse mode at 60 MHz with 15 MHz bandwidth. High and low-gain channels allow for recording a wide dynamic range of echoes simultaneously and without range-dependent gain control. Data acquisition includes integrations of 16 returned radar signals about every 15 cm along-track. Pulse compression and synthetic aperture radar (SAR) processing were components of data analysis. Subglacial echoes are influenced by the physical properties of the interface such as the composition and roughness of the materials at the interface. Other important factors include dielectric losses and volumetric scattering losses from propagation through the ice as well as transmission and refraction at the air-ice interface. Unfocussed SAR narrows the along

  11. Microbe-Clay Mineral Reactions and Characterization Techniques

    NASA Astrophysics Data System (ADS)

    Dong, H.; Zhang, G.; Ji, S.; Jaisi, D.; Kim, J.

    2008-12-01

    Clays and clay minerals are ubiquitous in soils, sediments, and sedimentary rocks. They play an important role in environmental processes such as nutrient cycling, plant growth, contaminant migration, organic matter maturation, and petroleum production. The changes in the oxidation state of the structural iron in clay minerals, in part, control their physical and chemical properties in natural environments, such as clay particle flocculation, dispersion, swelling, hydraulic conductivity, surface area, cation and anion exchange capacity, and reactivity towards organic and inorganic contaminants. The structural ferric iron [Fe(III)] in clay minerals can be reduced either chemically or biologically. Many different chemical reductants have been tried, but the most commonly used agent is dithionite. Biological reductants are bacteria, including dissimilatory iron reducing prokaryotes (DIRP) and sulfate-reducing bacteria (SRB). A wide variety of DIRP have been used to reduce ferric iron in clay minerals, including mesophilic, thermophilic, and hyperthermophilic prokaryotes. Multiple clay minerals have been used for microbial reduction studies, including smectite, nontronite (iron-rich smectite variety), illite, illite/smectite, chlorite, and their various mixtures. All these clay minerals are reducible by microorganisms under various conditions with smectite (nontronite) being the most reducible. The reduction extent and rate of ferric iron in clay minerals are measured by wet chemistry, and the reduced clay mineral products are typically characterized with chemical methods, X-ray diffraction, scanning and transmission electron microscopy, Mössbauer spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), UV-vis spectroscopy, and synchrotron-based techniques (such as EXAFS). Microbially reduced smectites (nontronites) have been found to be reactive in reducing a variety of organic and inorganic contaminants. Degradable organic contaminants include pesticides

  12. Advanced NDE techniques for quantitative characterization of aircraft

    NASA Technical Reports Server (NTRS)

    Heyman, Joseph S.; Winfree, William P.

    1990-01-01

    Recent advances in nondestructive evaluation (NDE) at NASA Langley Research Center and their applications that have resulted in quantitative assessment of material properties based on thermal and ultrasonic measurements are reviewed. Specific applications include ultrasonic determination of bolt tension, ultrasonic and thermal characterization of bonded layered structures, characterization of composite materials, and disbonds in aircraft skins.

  13. Characterization of Deep Tunneling Activity through Remote-Sensing Techniques

    SciTech Connect

    R. G. Best, P. J. Etzler, and J. D. Bloom

    1997-10-01

    This work is a case study demonstrating the uses of multispectral and multi-temporal imagery to characterize deep tunneling activity. A drainage tunnel excavation in Quincy, MA is the case locality. Data used are aerial photographs (digitized) and Daedalus 3600 MSS image data that were collected in July and October of 1994. Analysis of the data includes thermal characterization, spectral characterization, multi-temporal analysis, and volume estimation using digital DEM generation. The results demonstrate the type of information that could be generated by multispectral, multi-temporal data if the study locality were a clandestine excavation site with restricted surface access.

  14. Fabrication and static characterization of carbon-fiber-reinforced polymers with embedded NiTi shape memory wire actuators

    NASA Astrophysics Data System (ADS)

    de Araújo, C. J.; Rodrigues, L. F. A.; Coutinho Neto, J. F.; Reis, R. P. B.

    2008-12-01

    In this work, unidirectional carbon-fiber-reinforced polymers (CFRP) with embedded NiTi shape memory alloy (SMA) wire actuators were manufactured using a universal testing machine equipped with a thermally controlled chamber. Beam specimens containing cold-worked, annealed and trained NiTi SMA wires distributed along their neutral plane were fabricated. Several tests in a three-point bending mode at different constant temperatures were performed. To verify thermal buckling effects, electrical activation of the specimens was realized in a cantilevered beam mode and the influence of the SMA wire actuators on the tip deflection of the composite is demonstrated.

  15. In-die ultrasonic and off-line air-coupled monitoring and characterization techniques for drug tablets

    NASA Astrophysics Data System (ADS)

    Stephens, J. D.; Kowalczyk, B. R.; Hancock, B. C.; Kaul, G.; Akseli, I.; Cetinkaya, C.

    2012-05-01

    Mechanical integrity and properties of drug tablets may adversely affect their therapeutic and structural functions. An embedded ultrasound monitoring system for tablet mechanical property monitoring during compaction and a non-contact/non-destructive off-line air-coupled technique for determining the mechanical properties of coated drug tablets are presented. In the compaction monitoring system, the change of ToF and the reflection coefficient for the upper-punch surface interface as a function of compaction pressure has been studied. In the air-coupled measurement approach, air-coupled excitation and laser interferometric detection are utilized and their effectiveness in characterizing the mechanical properties of a drug tablet by examining its vibrational resonance frequencies is demonstrated. An iterative computational procedure based on the finite element method and Newton's method is developed to extract the mechanical properties of the coated tablet from a subset of its measured resonance frequencies. The mechanical properties characterized by this technique are compared to those obtained by a contact ultrasonic method.

  16. Immunohistochemical identification of Renibacterium salmoninarum by monoclonal antibodies in paraffin-embedded tissues of Atlantic salmon (Salmo salar L.), using paired immunoenzyme and paired immunofluorescence techniques.

    PubMed

    Evensen, O; Dale, O B; Nilsen, A

    1994-01-01

    Renibacterium salmoninarum was identified in situ by immunoenzymatic and immunofluorescence techniques in paraffin-embedded tissue specimens collected during a natural outbreak of bacterial kidney disease (BKD) and from an experimental infection in Atlantic salmon (Salmo salar L.). Monoclonal antibodies (MAbs) 4D3 and 2G5 were used in this study, both specific for the 57-58-kD outer membrane protein (p57) of the bacterium. Both MAbs revealed positive staining in ethanol-fixed tissue specimens, but only the epitope identified by MAb 4D3 was formalin resistant. Pretreatment with trypsin did not reestablish the antigenicity for the epitope identified by Mab 2G5. Paired immunoenzymatic staining for identification of the bacterium in sequential incubation steps on ethanol-fixed tissue specimens using an avidin-biotin-peroxidase system was obtained after serial dilution of the Mab (2G5) or the chromagen, amino ethyl carbazole, in the first sequence. Paired immunofluorescence staining with well-balanced color mixing was easily obtained on ethanol-fixed tissue specimens using sequential incubations. Single exposures gave blue (aminomethyl coumarin acetic acid) and green (fluorescein isothiocyanate) fluorescence for MAbs 2G5 and biotinylated 4D3, respectively. Color mixing was revealed as a turquoise staining. Studies on method sensitivity was performed by incorporating a known amount of a protein preparation of p57 into an inert matrix, creating an artificial test substrate.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8011782

  17. Flaw imaging and ultrasonic techniques for characterizing sintered silicon carbide

    NASA Technical Reports Server (NTRS)

    Baaklini, George Y.; Abel, Phillip B.

    1987-01-01

    The capabilities were investigated of projection microfocus x-radiography, ultrasonic velocity and attenuation, and reflection scanning acoustic microscopy for characterizing silicon carbide specimens. Silicon carbide batches covered a range of densities and different microstructural characteristics. Room temperature, four point flexural strength tests were conducted. Fractography was used to identify types, sizes, and locations of fracture origins. Fracture toughness values were calculated from fracture strength and flaw characterization data. Detection capabilities of radiography and acoustic microscopy for fracture-causing flaws were evaluated. Applicability of ultrasonics for verifying material strength and toughness was examined.

  18. Characterization of concrete materials by using stress wave NDE techniques

    NASA Astrophysics Data System (ADS)

    Sadri, Afshin; deWalle, Brian

    1999-12-01

    A new instrument for monitoring the quality of concrete materials has been developed by Andec Mfg. Ltd. This new instrument, the AndeScope, can be used to evaluate concrete materials by measuring the stress wave velocity, dynamic elastic constant, quality factor (Q-factor), signal frequency, and decay coefficient. The AndeScope can be used to estimate the strength gain at the setting time, or it can be used to diagnose problems such as Alkali-Silica Reaction (ASR) or micro fracturing. The three stress wave propagation techniques are used in combination for this evaluation: ultrasonic through-transmission, pulse-echo and impact-echo. The ultrasonic through-transmission technique uses a direct arrangement between the transmitting and receiving transducers, while the pulse-echo and impact-echo technique are used to monitor concrete materials and structures from a single available face. The AndeScope's three stress wave modes can also be used to detect flaws, delamination, thickness, honeycombing, and crack depth measurements. In this paper, the principles of the three stress wave techniques and actual functions of the instrument are described. The advantages and disadvantages of each technique and new methodologies are discussed.

  19. Fricke xylenol gel characterization using a photoacustic technique

    NASA Astrophysics Data System (ADS)

    Caldeira, A. M. F.; de Almeida, A.; Neto, A. M.; Baesso, M. L.; Bento, A. C.; Silva, M. A.

    2007-11-01

    Fricke chemical dosimetry measurements of the absorbed dose of ionizing radiation depend on the quality and characteristics of the system that reads each dosimeter. The final accuracy is significantly dependent on the technique used for measuring the chemical concentration changes in the dosimeters. We have used a photoacoustic technique to detect the Fricke xylenol gel (FXG) optical absorbance. The FXG, a derivation of the aqueous Fricke dosimeter, is made more sensitive and stable with addition of gelatin (300 Bloom) and xylenol orange. The light intensity transmitted through an FXG sample before and after irradiation was measured with an acoustic detector. The incremental optical absorbance is directly proportional to the ionizing radiation absorbed dose. We present the optical absorbance measurements as a function of absorbed dose and of post-irradiation time. We apply our photoacoustic technique to determine absorbed dose profiles. The results show that the photoacoustic technique applied to FXG provides a new dosimetric system, as good as those already established using spectrophotometric techniques.

  20. Spray characterization with a nonintrusive technique using absolute scattered light

    NASA Technical Reports Server (NTRS)

    Hess, C. F.; Espinosa, V. E.

    1984-01-01

    A technique to measure the size and velocity of particles is discussed, and results are presented. In this technique two small laser beams of one color identify the center of a laser beam of a different color. This defines a region of almost uniform intensity where the light scattered by the individual particles can be related to their sizes. A variation of this technique that uses two polarizations of the same color of laser beam is also presented. Results are presented for monodisperse, bimodal, trimodal, and polydisperse sprays produced by the Berglund-Liu droplet generator and a pressure nozzle. Size distributions obtained at three different ranges for the same spray show excellent self-consistency in the overlapping regions. Measurements of a spray of known characteristics exhibit errors in the order of 10 percent.

  1. Overview of characterization and metrology techniques for microlenses and microlens arrays

    NASA Astrophysics Data System (ADS)

    Kim, Myun-Sik; Allegre, Lisa; Sunarjo, Jonathan; Noell, Wilfried; Voelkel, Reinhard

    2015-05-01

    We review various metrology techniques for the characterization of refractive microlenses and microlens arrays (MLAs). The limitations and strength of each technique are analyzed. The goal is to obtain more stable and repeatable metrology routines for micro-optics manufacturing. This analysis comprises both techniques for the characterization of individual microlenses and the analysis of a very large number of microlenses in array configurations. Metrology of spherical and aspherical lens profiles, surface properties, aberrations, Strehl ratio, and focal properties will be presented.

  2. Characterizing nonconstant instrumental variance in emerging miniaturized analytical techniques.

    PubMed

    Noblitt, Scott D; Berg, Kathleen E; Cate, David M; Henry, Charles S

    2016-04-01

    Measurement variance is a crucial aspect of quantitative chemical analysis. Variance directly affects important analytical figures of merit, including detection limit, quantitation limit, and confidence intervals. Most reported analyses for emerging analytical techniques implicitly assume constant variance (homoskedasticity) by using unweighted regression calibrations. Despite the assumption of constant variance, it is known that most instruments exhibit heteroskedasticity, where variance changes with signal intensity. Ignoring nonconstant variance results in suboptimal calibrations, invalid uncertainty estimates, and incorrect detection limits. Three techniques where homoskedasticity is often assumed were covered in this work to evaluate if heteroskedasticity had a significant quantitative impact-naked-eye, distance-based detection using paper-based analytical devices (PADs), cathodic stripping voltammetry (CSV) with disposable carbon-ink electrode devices, and microchip electrophoresis (MCE) with conductivity detection. Despite these techniques representing a wide range of chemistries and precision, heteroskedastic behavior was confirmed for each. The general variance forms were analyzed, and recommendations for accounting for nonconstant variance discussed. Monte Carlo simulations of instrument responses were performed to quantify the benefits of weighted regression, and the sensitivity to uncertainty in the variance function was tested. Results show that heteroskedasticity should be considered during development of new techniques; even moderate uncertainty (30%) in the variance function still results in weighted regression outperforming unweighted regressions. We recommend utilizing the power model of variance because it is easy to apply, requires little additional experimentation, and produces higher-precision results and more reliable uncertainty estimates than assuming homoskedasticity. PMID:26995641

  3. Biochemistry and Molecular Biology Techniques for Person Characterization

    ERIC Educational Resources Information Center

    Herrero, Salvador; Ivorra, Jose Luis; Garcia-Sogo, Magdalena; Martinez-Cortina, Carmen

    2008-01-01

    Using the traditional serological tests and the most novel techniques for DNA fingerprinting, forensic scientists scan different traits that vary from person to person and use the data to include or exclude suspects based on matching with the evidence obtained in a criminal case. Although the forensic application of these methods is well known,…

  4. Nondestructive Measurement Material Characterization of Thermal Sprayed Nickel Aluminum Coatings by using Laser Ultrasound Technique

    NASA Astrophysics Data System (ADS)

    Yeh, Cheng Hung; Wu, Tai Chieh; Yang, Che Hua

    This research focused on characterization of mechanical properties in Nickel-Aluminum coating with different thermal technique and processing parameters at high temperature environment up to 295°C. With the laser ultrasound technique (LUT), guided acoustic waves are generated to propagate on the Ni-Al sprayed coatings. By measuring dispersive phase velocity followed by SCE-UA inversion algorithm. The Young's modulus of coatings which fabricated by HVOF technique is higher than APS technique. This technique is potentially useful to probe the material characterization at high temperature environment in a remote and non-destructive way.

  5. Application of Acoustic Techniques for Characterization of Biological Samples

    NASA Astrophysics Data System (ADS)

    Tittmann, Bernhard R.; Ebert, Anne

    The atomic force microscope (AFM) is emerging as a powerful tool in cell biology. Originally developed for high-resolution imaging purposes, the AFM also has unique capabilities as a nano-indenter to probe the dynamic viscoelastic material properties of living cells in culture. In particular, AFM elastography combines imaging and indentation modalities to map the spatial distribution of cell mechanical properties, which in turn reflect the structure and function of the underlying cytoskeleton. Such measurements have contributed to our understanding of cell mechanics and cell biology and appear to be sensitive to the presence of disease in individual cells. Examples of applications and considerations on the effective capability of ultrasonic AFM techniques on biological samples (both mammalian and plant) are reported in this chapter. Included in the discussion is scanning near-field ultrasound holography an acoustic technique which has been used to image structure and in particular nanoparticles inside cells. For illustration an example that is discussed in some detail is a technique for rapid in vitro single-cell elastography. The technique is based on atomic force acoustic microscopy (AFAM) but (1) requires only a few minutes of scan time, (2) can be used on live cells briefly removed from most of the nutrient fluid, (3) does negligible harm or damage to the cell, (4) provides semi-quantitative information on the distribution of modulus across the cell, and (5) yields data with 1-10 nm resolution. The technique is shown to enable rapid assessment of physical/biochemical signals on the cell modulus and contributes to current understanding of cell mechanics.

  6. System and technique for ultrasonic characterization of settling suspensions

    DOEpatents

    Greenwood, Margaret S.; Panetta, Paul D.; Bamberger, Judith A.; Pappas, Richard A.

    2006-11-28

    A system for determining properties of settling suspensions includes a settling container, a mixer, and devices for ultrasonic interrogation transverse to the settling direction. A computer system controls operation of the mixer and the interrogation devices and records the response to the interrogating as a function of settling time, which is then used to determine suspension properties. Attenuation versus settling time for dilute suspensions, such as dilute wood pulp suspension, exhibits a peak at different settling times for suspensions having different properties, and the location of this peak is used as one mechanism for characterizing suspensions. Alternatively or in addition, a plurality of ultrasound receivers are arranged at different angles to a common transmitter to receive scattering responses at a variety of angles during particle settling. Angular differences in scattering as a function of settling time are also used to characterize the suspension.

  7. Characterization of super smooth surfaces by light scattering techniques

    NASA Astrophysics Data System (ADS)

    Mattsson, Lars H.

    1989-03-01

    A characteristic feature of a supersmooth surface is its low scatter. The scatter is proportional to the square of the rms surface roughness. Therefore, light scattering is a suitable and nondestructive method for characterization of smooth surfaces. It is possible to detect scattering created by height differences of a few atomic layers but the lateral sensitivity is limited to the order of the wavelength, ~0.5μm. The new F 1048-87 ASTM standard test method for measuring the effective surface roughness of optical components is based on total integrated scattering (TIS). The amount of scattering, caused by the surface roughness, is of primary interest for optical applications, while the roughness itself is of greater concern in the fields of microelectronics and magnetic memory storage. This paper will highlight the use of a low noise TIS instrument for characterization of sub-Å roughness on semiconductor wafers, for thin film characterization, and for detection of traces of contamination on silicon surfaces.

  8. Genetic Characterization of Echinococcus granulosus from a Large Number of Formalin-Fixed, Paraffin-Embedded Tissue Samples of Human Isolates in Iran

    PubMed Central

    Rostami, Sima; Torbaghan, Shams Shariat; Dabiri, Shahriar; Babaei, Zahra; Mohammadi, Mohammad Ali; Sharbatkhori, Mitra; Harandi, Majid Fasihi

    2015-01-01

    Cystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus, presents an important medical and veterinary problem globally, including that in Iran. Different genotypes of E. granulosus have been reported from human isolates worldwide. This study identifies the genotype of the parasite responsible for human hydatidosis in three provinces of Iran using formalin-fixed paraffin-embedded tissue samples. In this study, 200 formalin-fixed paraffin-embedded tissue samples from human CE cases were collected from Alborz, Tehran, and Kerman provinces. Polymerase chain reaction amplification and sequencing of the partial mitochondrial cytochrome c oxidase subunit 1 gene were performed for genetic characterization of the samples. Phylogenetic analysis of the isolates from this study and reference sequences of different genotypes was done using a maximum likelihood method. In total, 54.4%, 0.8%, 1%, and 40.8% of the samples were identified as the G1, G2, G3, and G6 genotypes, respectively. The findings of the current study confirm the G1 genotype (sheep strain) to be the most prevalent genotype involved in human CE cases in Iran and indicates the high prevalence of the G6 genotype with a high infectivity for humans. Furthermore, this study illustrates the first documented human CE case in Iran infected with the G2 genotype. PMID:25535316

  9. Pulsed photothermal mirror technique: characterization of opaque materials.

    PubMed

    Capeloto, O A; Lukasievicz, G V B; Zanuto, V S; Herculano, L S; Souza Filho, N E; Novatski, A; Malacarne, L C; Bialkowski, S E; Baesso, M L; Astrath, N G C

    2014-11-20

    The time-resolved thermal mirror technique is developed under pulsed laser excitation for quantitative measurement of thermal and mechanical properties of opaque materials. Heat diffusion and thermoelastic equations are solved analytically for pulsed excitation assuming surface absorption and an instantaneous pulse. Analytical results for the temperature change and surface displacement in the sample are compared to all-numerical solutions using finite element method analysis accounting for the laser pulse width and sample geometry. Experiments are performed that validate the theoretical model and regression fitting is performed to obtain the thermal diffusivity and the linear thermal expansion coefficient of the samples. The values obtained for these properties are in agreement with literature data. The technique is shown to be useful for quantitative determinations of the physics properties of metals with high thermal diffusivity. PMID:25607877

  10. Demonstration to characterize watershed runoff potential by microwave techniques

    NASA Technical Reports Server (NTRS)

    Blanchard, B. J.

    1977-01-01

    Characteristics such as storage capacity of the soil, volume of storage in vegetative matter, and volume of storage available in local depressions are expressed in empirical watershed runoff equations as one or more coefficients. Conventional techniques for estimating coefficients representing the spatial distribution of these characteristics over a watershed drainage area are subjective and produce significant errors. Characteristics of the wear surface are described as a single coefficient called the curve number.

  11. In Situ Synthesis and Characterization of Ge Embedded Electrospun Carbon Nanostructures as High Performance Anode Material for Lithium-Ion Batteries.

    PubMed

    Lee, Young-Woo; Kim, Da-Mi; Kim, Si-Jin; Kim, Min-Cheol; Choe, Hui-Seon; Lee, Kyu-Ho; Sohn, Jung Inn; Cha, Seung Nam; Kim, Jong Min; Park, Kyung-Won

    2016-03-23

    While active materials based on germanium (Ge) are considered as a promising alternative anodic electrode due to their relatively high reversible capacity and excellent lithium-ion diffusivity, the quite unstable structural/electrochemical stability and severe volume expansion or pulverization problems of Ge electrodes remain a considerable challenge in lithium ion batteries (LIBs). Here, we present the development of Ge embedded in one-dimensional carbon nanostructures (Ge/CNs) synthesized by the modified in situ electrospinning technique using a mixed electrospun solution consisting of a Ge precursor as an active material source and polyacrylonitrile (PAN) as a carbon source. The as-prepared Ge/CNs exhibit superior lithium ion behavior properties, i.e., highly reversible specific capacity, rate performance, Li ion diffusion coefficient, and superior cyclic stability (capacity retention: 85% at 200 mA g(-1)) during Li alloying/dealloying processes. These properties are due to the high electrical conductivity and unique structures containing well-embedded Ge nanoparticles (NPs) and a one-dimensional carbon nanostructure as a buffer medium, which is related to the volume expansion of Ge NPs. Thus, it is expected that the Ge/CNs can be utilized as a promising alternative anodic material in LIBs. PMID:26895137

  12. Characterization of Magnetron Sputtered Coatings by Pulsed Eddy Current Techniques

    SciTech Connect

    Mulligan, Chris; Lee Changqing; Danon, Yaron

    2005-04-09

    A method that uses induced pulsed eddy currents for characterization of thick magnetron sputtered Nb coatings on steel is presented in this paper. The objectives of this work are to develop a system for rapid quantitative nondestructive inspection of coatings as well as to determine the correlation between coating properties, such as density and purity, and eddy current measured resistivity of coatings. A two-probe differential system having higher sensitivity and less noise than a one-probe system with 2-D scanning ability was developed.

  13. Using morphometric and analytical techniques to characterize elephant ivory.

    PubMed

    Singh, Rina Rani; Goyal, Surendra Prakash; Khanna, Param Pal; Mukherjee, Pulok Kumar; Sukumar, Raman

    2006-10-16

    There is a need to characterize Asian elephant ivory and compare with African ivory for controlling illegal trade and implementation of national and international laws. In this paper, we characterize ivory of Asian and African elephants using Schreger angle measurements, elemental analysis {X-ray fluorescence (XRF), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and inductively coupled plasma-mass spectroscopy (ICP-MS)} and isotopic analysis. We recorded Schreger angle characteristics of elephant ivory at three different zones in ivory samples of African (n=12) and Asian (n=28) elephants. The Schreger angle ranged from 32 degrees to 145 degrees and 30 degrees to 153 degrees in Asian and African ivory, respectively. Elemental analysis (for Asian and African ivory) by XRF, ICP-AES and ICP-MS provided preliminary data. We attempted to ascertain source of origin of Asian elephant ivory similarly as in African ivory based on isotopes of carbon, nitrogen and strontium. We determined isotopic ratios of carbon (n=31) and nitrogen (n=31) corresponding to diet and rainfall, respectively. Reference ivory samples from five areas within India were analyzed using collagen and powder sample and the latter was found more suitable for forensic analysis. During our preliminary analysis, the range of delta13C values (-13.6+/-0.15 per thousand and -25.6+/-0.15 per thousand) and delta15N values (10.2+/-0.15 per thousand and 3.5+/-0.15 per thousand) were noted. PMID:16891073

  14. Fabrication and characterization of a rapid prototyped tissue engineering scaffold with embedded multicomponent matrix for controlled drug release

    PubMed Central

    Chen, Muwan; Le, Dang QS; Hein, San; Li, Pengcheng; Nygaard, Jens V; Kassem, Moustapha; Kjems, Jørgen; Besenbacher, Flemming; Bünger, Cody

    2012-01-01

    Bone tissue engineering implants with sustained local drug delivery provide an opportunity for better postoperative care for bone tumor patients because these implants offer sustained drug release at the tumor site and reduce systemic side effects. A rapid prototyped macroporous polycaprolactone scaffold was embedded with a porous matrix composed of chitosan, nanoclay, and β-tricalcium phosphate by freeze-drying. This composite scaffold was evaluated on its ability to deliver an anthracycline antibiotic and to promote formation of mineralized matrix in vitro. Scanning electronic microscopy, confocal imaging, and DNA quantification confirmed that immortalized human bone marrow-derived mesenchymal stem cells (hMSC-TERT) cultured in the scaffold showed high cell viability and growth, and good cell infiltration to the pores of the scaffold. Alkaline phosphatase activity and osteocalcin staining showed that the scaffold was osteoinductive. The drug-release kinetics was investigated by loading doxorubicin into the scaffold. The scaffolds comprising nanoclay released up to 45% of the drug for up to 2 months, while the scaffold without nanoclay released 95% of the drug within 4 days. Therefore, this scaffold can fulfill the requirements for both bone tissue engineering and local sustained release of an anticancer drug in vitro. These results suggest that the scaffold can be used clinically in reconstructive surgery after bone tumor resection. Moreover, by changing the composition and amount of individual components, the scaffold can find application in other tissue engineering areas that need local sustained release of drug. PMID:22904634

  15. Integration of Scale Invariant Generator Technique and S-A Technique for Characterizing 2-D Patterns for Information Retrieve

    NASA Astrophysics Data System (ADS)

    Cao, L.; Cheng, Q.

    2004-12-01

    The scale invariant generator technique (SIG) and spectrum-area analysis technique (S-A) were developed independently relevant to the concept of the generalized scale invariance (GSI). The former was developed for characterizing the parameters involved in the GSI for characterizing and simulating multifractal measures whereas the latter was for identifying scaling breaks for decomposition of superimposed multifractal measures caused by multiple geophysical processes. A natural integration of these two techniques may yield a new technique to serve two purposes, on the one hand, that can enrich the power of S-A by increasing the interpretability of decomposed patterns in some applications of S-A and, on the other hand, that can provide a mean to test the uniqueness of multifractality of measures which is essential for application of SIG technique in more complicated environment. The implementation of the proposed technique has been done as a Dynamic Link Library (DLL) in Visual C++. The program can be friendly used for method validation and application in different fields.

  16. Characterization of a Mycobacterium intracellulare Variant Strain by Molecular Techniques

    PubMed Central

    Menendez, M. C.; Palenque, E.; Navarro, M. C.; Nuñez, M. C.; Rebollo, M. J.; Garcia, M. J.

    2001-01-01

    This paper describes a Mycobacterium intracellulare variant strain causing an unusual infection. Several isolates obtained from an immunocompromised patient were identified as members of the Mycobacterium avium complex (MAC) by the commercial AccuProbe system and biochemical standard identification. Further molecular approaches were undertaken for a more accurate characterization of the bacteria. Up to seven different genomic sequences were analyzed, ranging from conserved mycobacterial genes such as 16S ribosomal DNA to MAC-specific genes such as mig (macrophage-induced gene). The results obtained identify the isolates as a variant of M. intracellulare, an example of the internal variability described for members of the MAC, particularly within that species. The application of other molecular approaches is recommended for more accurate identification of bacteria described as MAC members. PMID:11724827

  17. Thermal Characterization of Carbon Nanotubes by Photothermal Techniques

    NASA Astrophysics Data System (ADS)

    Leahu, G.; Li Voti, R.; Larciprete, M. C.; Sibilia, C.; Bertolotti, M.; Nefedov, I.; Anoshkin, I. V.

    2015-06-01

    Carbon nanotubes (CNTs) are multifunctional materials commonly used in a large number of applications in electronics, sensors, nanocomposites, thermal management, actuators, energy storage and conversion, and drug delivery. Despite recent important advances in the development of CNT purity assessment tools and atomic resolution imaging of individual nanotubes by scanning tunnelling microscopy and high-resolution transmission electron microscopy, the macroscale assessment of the overall surface qualities of commercial CNT materials remains a great challenge. The lack of quantitative measurement technology to characterize and compare the surface qualities of bulk manufactured and engineered CNT materials has negative impacts on the reliable and consistent nanomanufacturing of CNT products. In this paper it is shown how photoacoustic spectroscopy and photothermal radiometry represent useful non-destructive tools to study the optothermal properties of carbon nanotube thin films.

  18. PIXE as a characterization technique in the cutting tool industry

    NASA Astrophysics Data System (ADS)

    Freemantle, C. S.; Sacks, N.; Topic, M.; Pineda-Vargas, C. A.

    2014-01-01

    Two WC-Co powders have been analyzed using micro-PIXE to identify elemental concentration and distribution. A powder recycled primarily from used mining components and a powder produced exclusively from fresh raw materials was studied. Elemental mapping of major elements as well as impurities, within powder granule cross sections, was performed. Contaminants (e.g. Fe and Ni) from manufacturing processes, as well as trace impurities (e.g. Cr, Cl, Ca and S) from recycling were detected, quantified and compared. The extent of increased concentrations of impurities resulting from recycling were observed, demonstrating the potential for PIXE as a characterization tool for detecting trace elements in cemented carbides, allowing for future improvements in the manufacturing and recycling processes.

  19. Characterization of drug iontophoresis with a fast microassay technique.

    PubMed Central

    Dionne, V E

    1976-01-01

    The iontophoretic release of drugs from micropipettes into free (Ringer's) solution was described using an ion-selective microelectrode assay method. This characterization, with a temporal resolution of 20 ms, showed that the equilibrium rate of drug transport was not linearly proportional to release current; the departure from linearity was increased by backing current and the result was demonstrated with analytically derived drug release functions. The general relation between the drug transport rate and release current was independent of the specific drug or pipette resistance; no functional relation was observed that might quantitatively predict this dependence without prior use of the assay. The diffusion coefficients at 25 degrees C in frog Ringer's of the drugs used in this study, all neuromuscular agonists, were determined: all values X 10(6) cm2/s; acetylcholine 6.11 +/- 0.30; carbamylcholine 7.44 +/- 0.34; 3-(m-hydroxyphenyl) prophyltrimethyl ammonium 5.79 +/- 0.13. PMID:938714

  20. Ground Penetrating Radar technique for railway track characterization in Portugal

    NASA Astrophysics Data System (ADS)

    De Chiara, Francesca; Fontul, Simona; Fortunato, Eduardo; D'Andrea, Antonio

    2013-04-01

    Maintenance actions are significant for transport infrastructures but, today, costs have to be necessary limited. A proper quality control since the construction phase is a key factor for a long life cycle and for a good economy policy. For this reason, suitable techniques have to be chosen and non-destructive tests represent an efficient solution, as they allow to evaluate infrastructure characteristics in a continuous or quasi-continuous way, saving time and costs, enabling to make changes if tests results do not comply with the project requirements. Ground Penetrating Radar (GPR) is a quick and effective technique to evaluate infrastructure condition in a continuous manner, replacing or reducing the use of traditional drilling method. GPR application to railways infrastructures, during construction and monitoring phase, is relatively recent. It is based on the measuring of layers thicknesses and detection of structural changes. It also enables the assessment of materials properties that constitute the infrastructure and the evaluation of the different types of defects such as ballast pockets, fouled ballast, poor drainage, subgrade settlement and transitions problems. These deteriorations are generally the causes of vertical deviations in track geometry and they cannot be detected by the common monitoring procedures, namely the measurements of track geometry. Moreover, the development of new GPR systems with higher antenna frequencies, better data acquisition systems, more user friendly software and new algorithms for calculation of materials properties can lead to a regular use of GPR. Therefore, it represents a reliable technique to assess track geometry problems and consequently to improve maintenance planning. In Portugal, rail inspection is performed with Plasser & Theurer EM120 equipment and recently 400 MHz IDS antennas were installed on it. GPR tests were performed on the Portuguese rail network and, as case study in this paper, a renewed track was

  1. Thermal characterization of nanofluids using laser induced thermal lens technique

    NASA Astrophysics Data System (ADS)

    Kurian, Achamma; Kumar, Rajesh B.; George, Sajan D.

    2009-08-01

    A laser induced thermal lens technique has been employed to evaluate the dynamic thermal parameter, the thermal diffusivity, of gold nanofluids. Gold nanoparticles were synthesized by citrate reduction of HAuCl4 in water. The UVVIS optical absorption spectra show an absorption peak around 540 nm owing to surface Plasmon resonance band of the gold particles. The thermal diffusivity of gold nanoparticles was evaluated by knowing the time constant of transient thermal lens obtained by fitting the experimental curve to the theoretical model of the mode-matched thermal lens. Analyses of the results show that the nanofluid exhibits lower thermal diffusivity value in comparison to the host medium, water. Further investigations also reveal that the concentration of nanoparticles in the fluid have influence on the measured thermal diffusivity value. Results are interpreted in terms of interfacial thermal resistance around the nanoparticles as well as on the clustering of nanoparticles.

  2. In-situ characterization technique for screening contaminated soils

    SciTech Connect

    Jaselskis, E.J.; Anderson, M.S.; D`Silva, A.P.; Baldwin, D.P.; Zamzow, D.S.

    1995-07-01

    An innovative field sampling system for screening contaminated soils has been developed using laser ablation coupled with inductively coupled plasma-atomic emission spectrometry (LA-ICP-AES) technology. This sampling approach provides in-situ real-time analysis of trace inorganic elements and is conducted through a mobile testing facility that consists of an instrumentation vehicle called the Mobile Demonstration Laboratory for Environmental Screening Technologies (MDLEST) and an attached trailer called the Robotic Sampling Accessory (RSA). The RSA provides automated sampling capabilities through an attached three-degree-of-freedom robot that is equipped with a surface-sampling probe. The MDLEST-RSA was successfully tested at a Department of Energy (DOE) site in Fernald, Ohio, during the fall of 1992. This paper provides a description of the analysis technique, the MDLEST and RSA, and results of the field demonstration. In addition, benefits, limitations, and future plans are also discussed.

  3. Modulation transfer function technique for real time radioscopic system characterization

    SciTech Connect

    Tobin, K.W. ); Brenizer, J.S. ); Mait, J.N. )

    1989-12-01

    At the University of Virginia neutron radiography facility, a modulation transfer function technique has been developed that can easily predict and compare the resolving characteristics of the real time system and the individual system components. We desired a simple method by which new system components could be analyzed to determine their image transfer characteristics and to estimate how they would affect the composite system during data acquisition. The method employed measures a small set of constant system parameters related to data collected across a cadmium cut-edge aperture. The effects of system noise and spatial variance on the measured data are reduced so that a representation of the true signal can be obtained for analysis. Resolution parameters for the total neutron radiography system and for the individual system components are reported.

  4. Modulation transfer function technique for real time radioscopic system characterization.

    PubMed

    Tobin, K W; Brenizer, J S; Mait, J N

    1989-12-01

    At the University of Virginia neutron radiography facility, a modulation transfer function technique has been developed that can easily predict and compare the resolving characteristics of the real time system and the individual system components. We desired a simple method by which new system components could be analyzed to determine their image transfer characteristics and to estimate how they would affect the composite system during data acquisition. The method employed measures a small set of constant system parameters related to data collected across a cadmium cut-edge aperture. The effects of system noise and spatial variance on the measured data are reduced so that a representation of the true signal can be obtained for analysis. Resolution parameters for the total neutron radiography system and for the individual system components are reported. PMID:20555991

  5. A New Spitzer IRAC Technique to Characterize Exoplanet Atmospheres

    NASA Astrophysics Data System (ADS)

    Krick, Jessica; Ingalls, J.; Carey, S.; von Braun, K.

    2012-05-01

    Spitzer’s extended warm mission gives us the opportunity to contribute to its legacy by performing comparative science on atmospheres of extrasolar planets. Observation of phase curves produce maps of the longitudinal brightness/temperature distributions in the planetary atmospheres, which are then used to calculate energy redistribution efficiencies between the hot dayside and cooler nightside - exoplanetary weather. Recent improvements in the calibration of IRAC make possible a new observing technique which will be much more efficient than standard staring mode observations by using snapshot observations to emulate a full phase curve. The challenge with using snapshot observations is in making sure all observing epochs can be tied together with high enough photometric precision. The dominant source of error in this task is intrapixel gain variations on sub pixel levels. We have effectively removed this source of error by using the Pointing Calibration and Reference Sensor (PCRS) onboard Spitzer for pointing repeatability that is significantly better than random pointing. Because we have achieved this excellent repeatability, we are able to build up a map of the intrapixel gain, which is then used to independently correct IRAC photometry as a function of position on the pixel. We discuss additional sources of noise below the gain variations, at the sub percent level, such as pixel-wise nonlinearities, and our efforts to remove them. We present preliminary 4.5 micron data of HD209458 where we compare staring mode observations to snapshots taken with this new technique, corrected by the gain and residual nonlinearity map, and comment on the scientific implications of the resultant phase curve.

  6. Characterizing a Brazilian sanitary landfill using geophysical seismic techniques.

    PubMed

    Abreu, A E S; Gandolfo, O C B; Vilar, O M

    2016-07-01

    Two different geophysical techniques, namely crosshole and multichannel analysis of surface waves - MASW, were applied to investigate the mechanical response of Municipal Solid Waste buried under humid, subtropical climate. Direct investigations revealed that the buried waste was composed mainly of soil-like material (51%) and plastics (31%) with moisture content average values of 43% near the surface and 53% after around 11m depth. Unit weight varied between 9kN/m(3) and 15kN/m(3). Seismic investigation of the landfill yielded shear wave velocities (VS) estimated from the crosshole tests ranging from 92 to 214m/s, while compression wave velocities (VP) ranged from 197 to 451m/s. Both velocities were influenced by vertical confining stress and thus tended to increase with depth. VS calculated from MASW tests were lower than the ones calculated from the crosshole tests, probably due to the different frequencies used in the tests. The results of both methods tended to configure a lower bound to the values reported in the technical literature in general, as expected for low compaction waste with small amounts of cover soil. Although VS did not show abrupt changes with depth, VP profile distribution combined with direct investigations results, such as temperature, in-place unit weight and moisture content, suggest that the waste body could be divided into two strata. The lower one is poorly drained and shows higher moisture content, as a consequence of the operational techniques used in the first years, while the upper stratum is probably related to a better drained waste stratum, resulting from the improvement of operational standards and increase in drainage facilities throughout the years. PMID:27107707

  7. Novel monitoring techniques for characterizing frictional interfaces in the laboratory.

    PubMed

    Selvadurai, Paul A; Glaser, Steven D

    2015-01-01

    A pressure-sensitive film was used to characterize the asperity contacts along a polymethyl methacrylate (PMMA) interface in the laboratory. The film has structural health monitoring (SHM) applications for flanges and other precision fittings and train rail condition monitoring. To calibrate the film, simple spherical indentation tests were performed and validated against a finite element model (FEM) to compare normal stress profiles. Experimental measurements of the normal stress profiles were within -7.7% to 6.6% of the numerical calculations between 12 and 50 MPa asperity normal stress. The film also possessed the capability of quantifying surface roughness, an important parameter when examining wear and attrition in SHM applications. A high definition video camera supplied data for photometric analysis (i.e., the measure of visible light) of asperities along the PMMA-PMMA interface in a direct shear configuration, taking advantage of the transparent nature of the sample material. Normal stress over individual asperities, calculated with the pressure-sensitive film, was compared to the light intensity transmitted through the interface. We found that the luminous intensity transmitted through individual asperities linearly increased 0.05643 ± 0.0012 candelas for an increase of 1 MPa in normal stress between normal stresses ranging from 23 to 33 MPa. PMID:25923930

  8. Novel Monitoring Techniques for Characterizing Frictional Interfaces in the Laboratory

    PubMed Central

    Selvadurai, Paul A.; Glaser, Steven D.

    2015-01-01

    A pressure-sensitive film was used to characterize the asperity contacts along a polymethyl methacrylate (PMMA) interface in the laboratory. The film has structural health monitoring (SHM) applications for flanges and other precision fittings and train rail condition monitoring. To calibrate the film, simple spherical indentation tests were performed and validated against a finite element model (FEM) to compare normal stress profiles. Experimental measurements of the normal stress profiles were within −7.7% to 6.6% of the numerical calculations between 12 and 50 MPa asperity normal stress. The film also possessed the capability of quantifying surface roughness, an important parameter when examining wear and attrition in SHM applications. A high definition video camera supplied data for photometric analysis (i.e., the measure of visible light) of asperities along the PMMA-PMMA interface in a direct shear configuration, taking advantage of the transparent nature of the sample material. Normal stress over individual asperities, calculated with the pressure-sensitive film, was compared to the light intensity transmitted through the interface. We found that the luminous intensity transmitted through individual asperities linearly increased 0.05643 ± 0.0012 candelas for an increase of 1 MPa in normal stress between normal stresses ranging from 23 to 33 MPa. PMID:25923930

  9. Faulted reservoirs characterization by an image processing technique

    SciTech Connect

    Martinez-Angeles, R.

    1994-12-31

    This paper has developed an image processing method for obtaining the discontinuous areal distribution of oil parameters (formation top, porosity, water saturation,...) of faulted heterogeneous oil reservoirs. For its application it requires the previous knowledge of a set of discrete values z(k,l) from well-logs and seismic profiles. Faulted structures were discretized into continuous structures or blocks bounded by faults. The theoretical fundamental assumption of the proposed method establishes that the natural distributions can be considered as the superposition of several elementary brownian distributions, represented by discrete values z(k,l), whose physical model is the diffusion differential equation and its solution associated. This is a technique that allows the representation of a composed brownian distribution as a linear combination of all elementary brownian functions. For illustrating the operational aspect of brownian analysis, two examples are studied. The results are presented as a digital images by means of an image processing software. This method can be applied in mapping, three dimensions interpolation and reserves calculation of faulted reservoirs.

  10. Hyperspectral-imaging-based techniques applied to wheat kernels characterization

    NASA Astrophysics Data System (ADS)

    Serranti, Silvia; Cesare, Daniela; Bonifazi, Giuseppe

    2012-05-01

    Single kernels of durum wheat have been analyzed by hyperspectral imaging (HSI). Such an approach is based on the utilization of an integrated hardware and software architecture able to digitally capture and handle spectra as an image sequence, as they results along a pre-defined alignment on a surface sample properly energized. The study was addressed to investigate the possibility to apply HSI techniques for classification of different types of wheat kernels: vitreous, yellow berry and fusarium-damaged. Reflectance spectra of selected wheat kernels of the three typologies have been acquired by a laboratory device equipped with an HSI system working in near infrared field (1000-1700 nm). The hypercubes were analyzed applying principal component analysis (PCA) to reduce the high dimensionality of data and for selecting some effective wavelengths. Partial least squares discriminant analysis (PLS-DA) was applied for classification of the three wheat typologies. The study demonstrated that good classification results were obtained not only considering the entire investigated wavelength range, but also selecting only four optimal wavelengths (1104, 1384, 1454 and 1650 nm) out of 121. The developed procedures based on HSI can be utilized for quality control purposes or for the definition of innovative sorting logics of wheat.

  11. Diagnosis of industrial catalyst deactivation by surface characterization techniques

    SciTech Connect

    Menon, P.G. . Lab. voor Petrochemische Techniek Chalmers Univ. of Technology, Goeteborg . Dept. of Engineering Chemistry)

    1994-06-01

    The exact nature of the catalyst surface and the various ways of catalyst deactivation are subjects of great scientific interest and enormous economic importance. A brief review like the present one has to be very selective, giving only the underlying principles and representative examples. The focus of this review is on industrial catalysts, in particular, on the most commonly used supported metal and mixed-oxide type catalysts. Here again, only typical examples are chosen and cited to illustrate the specific types of problems involved in catalyst deactivation and how these problems wee diagnosed by a judicious application of the experimental techniques available today. Of the types of catalyst deactivation caused by coking, poisoning, and solid-state transformations, the emphasis in this review is on the last type. Changes in the chemical composition of the catalyst surface, restructuring or reconstruction of the surface, phase transformations, gradual enrichment/depletion of a particular catalyst component on/from the catalyst surface, these are the topics of prominence in this review. Even here, emphasis is on normally unexpected or unsuspected types of deactivation and the catalyst metamorphosis produced by the catalytic reaction itself, as distinct from the purely thermal effects at the reaction temperature. This review is aimed to provide some essential background information and possibly to serve as a reference guide for trouble-shooting when a catalyst is deactivated for rather mysterious reasons. 147 refs.

  12. Development of Reservoir Characterization Techniques and Production Models for Exploiting Naturally Fractured Reservoirs

    SciTech Connect

    Wiggins, Michael L.; Brown, Raymon L.; Civan, Frauk; Hughes, Richard G.

    2001-08-15

    Research continues on characterizing and modeling the behavior of naturally fractured reservoir systems. Work has progressed on developing techniques for estimating fracture properties from seismic and well log data, developing naturally fractured wellbore models, and developing a model to characterize the transfer of fluid from the matrix to the fracture system for use in the naturally fractured reservoir simulator.

  13. Mechanism for single-event burnout of power MOSFETs and its characterization technique

    NASA Astrophysics Data System (ADS)

    Kuboyama, S.; Matsuda, S.; Kanno, T.; Ishii, T.

    1992-12-01

    A novel characterization technique for single event burnout (SEB) of power MOSFETs was developed. The technique is based on a pulse-height analyzer system for charge collection measurement with a modified charge-sensitive amplifier which has a very wide dynamic range. The data obtained by this technique give detailed information about the SEB mechanism of power MOSFETs. The experimental data suggested a position-independent charge collection mechanism along an ion track, and a new parameter for SEB hardness was proposed.

  14. Color metallography and electron microscopy techniques applied to the characterization of 413.0 aluminum alloys.

    PubMed

    Vander Voort, George; Asensio-Lozano, Juan; Suárez-Peña, Beatriz

    2013-08-01

    The influence on alloy 413.0 of the refinement and modification of its microstructure was analyzed by means of several microscopy techniques, as well as the effect of the application of high pressure during solidification. For each treatment and solidification pressure condition employed, the most suitable microscopy techniques for identifying and characterizing the phases present were investigated. Color metallography and electron microscopy techniques were applied to the qualitative microstructural analysis. Volume fraction and grain size of the primary α-Al were characterized by quantitative metallographic techniques. The results show that the effect caused by applying high pressure during solidification of the alloy is more pronounced than that caused by modification and refinement of the microstructure when it solidifies at atmospheric pressure. Furthermore, it has been shown that, for Al-Si alloy characterization, when aiming to characterize the primary α-Al phase, optical color metallography observed under crossed polarized light plus a sensitive tint filter is the most suitable technique. When the goal is to characterize the eutectic Si, the use of optical color metallography or electron microscopy is equally valid. The characterization of iron-rich intermetallic compounds should preferably be performed by means of backscattered electron imaging. PMID:23701972

  15. Nondestructive techniques for characterizing mechanical properties of structural materials - An overview

    NASA Technical Reports Server (NTRS)

    Vary, A.; Klima, S. J.

    1986-01-01

    An overview of nondestructive evaluation (NDE) is presented to indicate the availability and application potentials of techniques for quantitative characterization of the mechanical properties of structural materials. The purpose is to review NDE techniques that go beyond the usual emphasis on flow detection and characterization. Discussed are current and emerging NDE techniques that can verify and monitor entrinsic properties (e.g., tensile, shear, and yield strengths; fracture toughness, hardness, ductility; elastic moduli) and underlying microstructural and morphological factors. Most of the techniques described are, at present, neither widely applied nor widely accepted in commerce and industry because they are still emerging from the laboratory. The limitations of the techniques may be overcome by advances in applications research and instrumentation technology and perhaps by accommodations for their use in the design of structural parts.

  16. Nondestructive techniques for characterizing mechanical properties of structural materials: An overview

    NASA Technical Reports Server (NTRS)

    Vary, A.; Klima, S. J.

    1985-01-01

    An overview of nondestructive evaluation (NDE) is presented to indicate the availability and application potentials of techniques for quantitative characterization of the mechanical properties of structural materials. The purpose is to review NDE techniques that go beyond the usual emphasis on flaw detection and characterization. Discussed are current and emerging NDE techniques that can verify and monitor entrinsic properties (e.g., tensile, shear, and yield strengths; fracture toughness, hardness, ductility; elastic moduli) and underlying microstructural and morphological factors. Most of the techniques described are, at present, neither widely applied nor widely accepted in commerce and industry because they are still emerging from the laboratory. The limitations of the techniques may be overcome by advances in applications research and instrumentation technology and perhaps by accommodations for their use in the design of structural parts.

  17. Gel-embedded niosomes: preparation, characterization and release studies of a new system for topical drug delivery.

    PubMed

    Coviello, T; Trotta, A M; Marianecci, C; Carafa, M; Di Marzio, L; Rinaldi, F; Di Meo, C; Alhaique, F; Matricardi, P

    2015-01-01

    In the present paper physical gels, prepared with two polysaccharides, Xanthan and Locust Bean Gum, and loaded with non-ionic surfactant vesicles, are described. The vesicles, composed by Tween20 and cholesterol or by Tween85 and Span20, were loaded with Monoammonium glycyrrhizinate for release experiments. Size and zeta (ζ)-potential of the vesicles were evaluated and the new systems were characterized by rheological and dynamo-mechanical measurements. For an appropriate comparison, a Carbopol gel and a commercial gel for topical applications were also tested. The new formulations showed mechanical properties comparable with those of the commercial product indicating their suitability for topical applications. In vitro release experiments showed that the polysaccharide network protects the integrity of the vesicles and leads to their slow release without disruption of the aggregated structures. Furthermore, being the vesicles composed of molecules possessing enhancing properties, the permeation of the loaded drugs topically delivered can be improved. Thus, the new systems combine the advantages of matrices for a modified release (polymeric component) and those of an easier permeability across the skin (vesicle components). Finally, shelf live experiments indicated that the tested gel/vesicle formulations were stable over 1 year with no need of preservatives. PMID:25524220

  18. Technical textiles with embedded fibre Bragg grating sensors

    NASA Astrophysics Data System (ADS)

    Bilro, L.; Cunha, H.; Pinto, J. L.; Nogueira, R. N.

    2009-10-01

    The characterization of fiber Bragg grating (FBG) sensors integrated on 2D and 3D mesh structures is presented. Several materials and configurations were tested, namely cork, foams, PVC, hexagonal 3D. Sensors were embedded between two substrates using textile lamination technique. Every sample was subjected to temperature variations and mechanical deformations. Through Bragg wavelength monitoring, thermal, deformation and pressure performance were evaluated. These results provide significant information to the conception of smart textiles.

  19. Recent Experience Using Active Love Wave Techniques to Characterize Seismographic Station Sites

    NASA Astrophysics Data System (ADS)

    Martin, A. J.; Yong, A.; Salomone, L.

    2014-12-01

    Active-source Love waves recorded by the multi-channel analysis of surface wave (MASLW) technique were recently analyzed in two site characterization projects. Between 2010 and 2011, the 2009 American Recovery and Reinvestment Act (ARRA) funded GEOVision to conduct geophysical investigations at 189 seismographic stations—185 in California and 4 in the Central Eastern U.S. (CEUS). The original project plan was to utilize active and passive Rayleigh wave-based techniques to obtain shear-wave velocity (VS) profiles to a minimum depth of 30 m and the time-averaged VS of the upper 30 meters (VS30). Early in the investigation it became evident that Rayleigh wave techniques, such as multi-channel analysis of surface waves (MASRW), were not effective at characterizing all sites. Shear-wave seismic refraction and MASLW techniques were therefore applied. The MASLW technique was deployed at a total of 38 sites, in addition to other methods, and used as the primary technique to characterize 22 sites, 5 of which were also characterized using Rayleigh wave techniques. In 2012, the Electric Power Research Institute funded characterization of 33 CEUS station sites. Based on experience from the ARRA investigation, both MASRW and MASLW data were acquired by GEOVision at 24 CEUS sites—the remaining 9 sites and 2 overlapping sites were characterized by University of Texas, Austin. Of the 24 sites characterized by GEOVision, 16 were characterized using MASLW data, 4 using both MASLW and MASRW data and 4 using MASRW data. Love wave techniques were often found to perform better, or at least yield phase velocity data that could be more readily modeled using the fundamental mode assumption, at shallow rock sites, sites with steep velocity gradients, and, sites with a thin, low velocity, surficial soil layer overlying stiffer sediments. These types of velocity structure often excite dominant higher modes in Rayleigh wave data, but not in Love wave data. At such sites, it may be possible

  20. Depth profile characterization technique for electron density in GaN films by infrared reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Kamijoh, Takaaki; Ma, Bei; Morita, Ken; Ishitani, Yoshihiro

    2016-05-01

    Infrared reflectance spectroscopy is a noncontact measurement method for carrier density and mobility. In this article, the model determination procedure of layer-type nonuniform electron distribution is investigated, since the spectrum fitting hitherto has been conducted on the basis of a multilayer model defined in advance. A simplified case of a high-electron-density GaN layer embedded in a GaN matrix is mainly studied. The following procedure is found to be applicable. The first step is the determination of the high-density layer position in the vicinity of the surface, in the middle region, or in the vicinity of the interface. This is followed by the specification of the sheet electron density and the layer thickness of the high-density region. It is found that this procedure is also applicable to the characterization of two-dimensional electron gases in the vicinity of AlGaN/GaN heterointerfaces.

  1. Ultrasound Imaging Techniques for Spatiotemporal Characterization of Composition, Microstructure, and Mechanical Properties in Tissue Engineering.

    PubMed

    Deng, Cheri X; Hong, Xiaowei; Stegemann, Jan P

    2016-08-01

    Ultrasound techniques are increasingly being used to quantitatively characterize both native and engineered tissues. This review provides an overview and selected examples of the main techniques used in these applications. Grayscale imaging has been used to characterize extracellular matrix deposition, and quantitative ultrasound imaging based on the integrated backscatter coefficient has been applied to estimating cell concentrations and matrix morphology in tissue engineering. Spectral analysis has been employed to characterize the concentration and spatial distribution of mineral particles in a construct, as well as to monitor mineral deposition by cells over time. Ultrasound techniques have also been used to measure the mechanical properties of native and engineered tissues. Conventional ultrasound elasticity imaging and acoustic radiation force imaging have been applied to detect regions of altered stiffness within tissues. Sonorheometry and monitoring of steady-state excitation and recovery have been used to characterize viscoelastic properties of tissue using a single transducer to both deform and image the sample. Dual-mode ultrasound elastography uses separate ultrasound transducers to produce a more potent deformation force to microscale characterization of viscoelasticity of hydrogel constructs. These ultrasound-based techniques have high potential to impact the field of tissue engineering as they are further developed and their range of applications expands. PMID:26771992

  2. TOPICAL REVIEW Organic photovoltaics: principles and techniques for nanometre scale characterization

    NASA Astrophysics Data System (ADS)

    Nicholson, Patrick G.; Castro, Fernando A.

    2010-12-01

    The photoconversion efficiency of state-of-the-art organic solar cells has experienced a remarkable increase in the last few years, with reported certified efficiency values of up to 8.3%. This increase has been due to an improved understanding of the underlying physics, synthetic discovery and the realization of the pivotal role that morphological optimization plays. Advances in nanometre scale characterization have underpinned all three factors. Here we give an overview of the current understanding of the fundamental processes in organic photovoltaic devices, on optimization considerations and on recent developments in nanometre scale measuring techniques. Finally, recommendations for future developments from the perspective of characterization techniques are set forth.

  3. Template Synthesis Of Copper Nanowires Via Electrodeposition Technique And Their Characterization

    SciTech Connect

    Kumar, Narinder; Kumar, Rajesh; Kumar, Sushil; Chakarvarti, S. K.

    2011-12-12

    Copper nanowires have been synthesized successfully using template assisted electrodeposition technique. Commercial polycarbonate membrane (Whatman, Japan) having pore diameter 100 nm, thickness 10 {mu}m and pore density 10{sup 7} pores/cm{sup 2} was used as template. Scanning electron microscopy and X-ray diffraction techniques were used to characterize the synthesized copper nanowires. XRD and SEM results reveal that polycrystalline copper nanowires were obtained with fcc lattice structure having diameter equal to the diameter of the template used.

  4. Characterization techniques for semiconductors and nanostructures: a review of recent advances

    NASA Astrophysics Data System (ADS)

    Acher, Olivier

    2015-01-01

    Optical spectroscopy techniques are widely used for the characterization of semiconductors and nanostructures. Confocal Raman microscopy is useful to retrieve chemical and molecular information at the ultimate submicrometer resolution of optical microscopy. Fast imaging capabilities, 3D confocal ability, and multiple excitation wavelengths, have increased the power of the technique while making it simpler to use for material scientists. Recently, the development of the Tip Enhanced Raman Spectroscopy (TERS) has opened the way to the use of Raman information at nanoscale, by combining the resolution of scanning probe microscopy and chemical selectivity of Raman spectroscopy. Significant advances have been reported in the field of profiling the atomic composition of multilayers, using the Glow Discharge Optical Emission Spectroscopy technique, including real-time determination of etched depth by interferometry. This allows the construction of precise atomic profiles of sophisticated multilayers with a few nm resolution. Ellipsometry is another widely used technique to determine the profile of multilayers, and recent development have provided enhanced spatial resolution useful for the investigation of patterned materials. In addition to the advances of the different characterization techniques, the capability to observe the same regions at micrometer scale at different stages of material elaboration, or with different instrument, is becoming a critical issue. Several advances have been made to allow precise re-localization and co-localization of observation with different complementary characterization techniques.

  5. A Systematic Characterization of Cognitive Techniques for Learning from Textual and Pictorial Representations

    ERIC Educational Resources Information Center

    Ploetzner, Rolf; Lowe, Richard; Schlag, Sabine

    2013-01-01

    Pictorial representations can play a pivotal role in both printed and digital learning material. Although there has been extensive research on cognitive techniques and strategies for learning from text, the same cannot be said for static and dynamic pictorial representations. In this paper we propose a systematic characterization of cognitive…

  6. Analytical techniques for characterization of cyclodextrin complexes in the solid state: A review.

    PubMed

    Mura, Paola

    2015-09-10

    Cyclodextrins are cyclic oligosaccharides able to form inclusion complexes with a variety of hydrophobic guest molecules, positively modifying their physicochemical properties. A thorough analytical characterization of cyclodextrin complexes is of fundamental importance to provide an adequate support in selection of the most suitable cyclodextrin for each guest molecule, and also in view of possible future patenting and marketing of drug-cyclodextrin formulations. The demonstration of the actual formation of a drug-cyclodextrin inclusion complex in solution does not guarantee its existence also in the solid state. Moreover, the technique used to prepare the solid complex can strongly influence the properties of the final product. Therefore, an appropriate characterization of the drug-cyclodextrin solid systems obtained has also a key role in driving in the choice of the most effective preparation method, able to maximize host-guest interactions. The analytical characterization of drug-cyclodextrin solid systems and the assessment of the actual inclusion complex formation is not a simple task and involves the combined use of several analytical techniques, whose results have to be evaluated together. The objective of the present review is to present a general prospect of the principal analytical techniques which can be employed for a suitable characterization of drug-cyclodextrin systems in the solid state, evidencing their respective potential advantages and limits. The applications of each examined technique are described and discussed by pertinent examples from literature. PMID:25743620

  7. Embedding Optical Fibers In Cast Metal Parts

    NASA Technical Reports Server (NTRS)

    Gibler, William N.; Atkins, Robert A.; Lee, Chung E.; Taylor, Henry F.

    1995-01-01

    Use of metal strain reliefs eliminates breakage of fibers during casting process. Technique for embedding fused silica optical fibers in cast metal parts devised. Optical fiber embedded in flange, fitting, or wall of vacuum or pressure chamber, to provide hermetically sealed feedthrough for optical transmission of measurement or control signals. Another example, optical-fiber temperature sensor embedded in metal structural component to measure strain or temperature inside component.

  8. Lithographically fabricated silicon microreactor for in situ characterization of heterogeneous catalysts—Enabling correlative characterization techniques

    NASA Astrophysics Data System (ADS)

    Baier, S.; Rochet, A.; Hofmann, G.; Kraut, M.; Grunwaldt, J.-D.

    2015-06-01

    We report on a new modular setup on a silicon-based microreactor designed for correlative spectroscopic, scattering, and analytic on-line gas investigations for in situ studies of heterogeneous catalysts. The silicon microreactor allows a combination of synchrotron radiation based techniques (e.g., X-ray diffraction and X-ray absorption spectroscopy) as well as infrared thermography and Raman spectroscopy. Catalytic performance can be determined simultaneously by on-line product analysis using mass spectrometry. We present the design of the reactor, the experimental setup, and as a first example for an in situ study, the catalytic partial oxidation of methane showing the applicability of this reactor for in situ studies.

  9. Lithographically fabricated silicon microreactor for in situ characterization of heterogeneous catalysts—Enabling correlative characterization techniques.

    PubMed

    Baier, S; Rochet, A; Hofmann, G; Kraut, M; Grunwaldt, J-D

    2015-06-01

    We report on a new modular setup on a silicon-based microreactor designed for correlative spectroscopic, scattering, and analytic on-line gas investigations for in situ studies of heterogeneous catalysts. The silicon microreactor allows a combination of synchrotron radiation based techniques (e.g., X-ray diffraction and X-ray absorption spectroscopy) as well as infrared thermography and Raman spectroscopy. Catalytic performance can be determined simultaneously by on-line product analysis using mass spectrometry. We present the design of the reactor, the experimental setup, and as a first example for an in situ study, the catalytic partial oxidation of methane showing the applicability of this reactor for in situ studies. PMID:26133867

  10. Lithographically fabricated silicon microreactor for in situ characterization of heterogeneous catalysts—Enabling correlative characterization techniques

    SciTech Connect

    Baier, S.; Rochet, A.; Hofmann, G.; Kraut, M.; Grunwaldt, J.-D.

    2015-06-15

    We report on a new modular setup on a silicon-based microreactor designed for correlative spectroscopic, scattering, and analytic on-line gas investigations for in situ studies of heterogeneous catalysts. The silicon microreactor allows a combination of synchrotron radiation based techniques (e.g., X-ray diffraction and X-ray absorption spectroscopy) as well as infrared thermography and Raman spectroscopy. Catalytic performance can be determined simultaneously by on-line product analysis using mass spectrometry. We present the design of the reactor, the experimental setup, and as a first example for an in situ study, the catalytic partial oxidation of methane showing the applicability of this reactor for in situ studies.

  11. Nondestructive evaluation techniques for development and characterization of carbon nanotube based superstructures

    NASA Astrophysics Data System (ADS)

    Wincheski, Buzz; Kim, Jae-Woo; Sauti, Godfrey; Wainwright, Elliot; Williams, Phillip; Siochi, Emile J.

    2015-03-01

    Recently, multiple commercial vendors have developed capability for the production of large-scale quantities of high-quality carbon nanotube sheets and yarns [1]. While the materials have found use in electrical shielding applications, development of structural systems composed of a high volume fraction of carbon nanotubes is still lacking [2]. A recent NASA program seeks to address this by prototyping a structural nanotube composite with strength-to-weight ratio exceeding current state-of-the-art carbon fiber composites. Commercially available carbon nanotube sheets, tapes, and yarns are being processed into high volume fraction carbon nanotube-polymer nanocomposites. Nondestructive evaluation techniques have been applied throughout this development effort for material characterization and process control. This paper will report on the progress of these efforts, including magnetic characterization of residual catalyst content, Raman scattering characterization of nanotube diameter and nanotube strain, and polarized Raman scattering for characterization of nanotube alignment.

  12. Nondestructive Evaluation Techniques for Development and Characterization of Carbon Nanotube Based Superstructures

    NASA Technical Reports Server (NTRS)

    Wincheski, Buzz; Kim, Jae-Woo; Sauti, Godfrey; Wainwright, Elliot; Williams, Phillip; Siochi, Emile J.

    2014-01-01

    Recently, multiple commercial vendors have developed capability for the production of large-scale quantities of high-quality carbon nanotube sheets and yarns. While the materials have found use in electrical shielding applications, development of structural systems composed of a high volume fraction of carbon nanotubes is still lacking. A recent NASA program seeks to address this by prototyping a structural nanotube composite with strength-toweight ratio exceeding current state-of-the-art carbon fiber composites. Commercially available carbon nanotube sheets, tapes, and yarns are being processed into high volume fraction carbon nanotube-polymer nanocomposites. Nondestructive evaluation techniques have been applied throughout this development effort for material characterization and process control. This paper will report on the progress of these efforts, including magnetic characterization of residual catalyst content, Raman scattering characterization of nanotube diameter, defect ratio, and nanotube strain, and polarized Raman scattering for characterization of nanotube alignment.

  13. Embedded Thermal Control for Subsystems for Next Generation Spacecraft Applications

    NASA Technical Reports Server (NTRS)

    Didion, Jeffrey R.

    2015-01-01

    Thermal Fluids and Analysis Workshop, Silver Spring MD NCTS 21070-15. NASA, the Defense Department and commercial interests are actively engaged in developing miniaturized spacecraft systems and scientific instruments to leverage smaller cheaper spacecraft form factors such as CubeSats. This paper outlines research and development efforts among Goddard Space Flight Center personnel and its several partners to develop innovative embedded thermal control subsystems. Embedded thermal control subsystems is a cross cutting enabling technology integrating advanced manufacturing techniques to develop multifunctional intelligent structures to reduce Size, Weight and Power (SWaP) consumption of both the thermal control subsystem and overall spacecraft. Embedded thermal control subsystems permit heat acquisition and rejection at higher temperatures than state of the art systems by employing both advanced heat transfer equipment (integrated heat exchangers) and high heat transfer phenomena. The Goddard Space Flight Center Thermal Engineering Branch has active investigations seeking to characterize advanced thermal control systems for near term spacecraft missions. The embedded thermal control subsystem development effort consists of fundamental research as well as development of breadboard and prototype hardware and spaceflight validation efforts. This paper will outline relevant fundamental investigations of micro-scale heat transfer and electrically driven liquid film boiling. The hardware development efforts focus upon silicon based high heat flux applications (electronic chips, power electronics etc.) and multifunctional structures. Flight validation efforts include variable gravity campaigns and a proposed CubeSat based flight demonstration of a breadboard embedded thermal control system. The CubeSat investigation is technology demonstration will characterize in long-term low earth orbit a breadboard embedded thermal subsystem and its individual components to develop

  14. Metal embedded Fiber Brag Grating Sensors

    NASA Astrophysics Data System (ADS)

    Khanal, Chooda; Vargas, Garman; Balani, Kantesh; Keshri, Anup; Barbosa, Carmen; Agarwal, Arvind; Panepucci, Roberto

    2009-03-01

    A novel method of embedding optical fibers and optical fiber sensors, inside metallic structures will be discussed. We specifically report results for embedding fiber bragg grating sensors in an aluminum coating onto a steel plate. Characterization of an embedded FBG sensor and its effects on the sensor operation are also presented. Temperature sensitivity and the strain sensitivity will be discussed. The novel high throughput deposition method show the potential of embedding optical sensors onto metallic structures which make it suitable for many engineering applications in biomedical, civil, mechanical and aeronautical, among other fields.

  15. Evaluating Local Primary Dendrite Arm Spacing Characterization Techniques Using Synthetic Directionally Solidified Dendritic Microstructures

    NASA Astrophysics Data System (ADS)

    Tschopp, Mark A.; Miller, Jonathan D.; Oppedal, Andrew L.; Solanki, Kiran N.

    2015-10-01

    Microstructure characterization continues to play an important bridge to understanding why particular processing routes or parameters affect the properties of materials. This statement certainly holds true in the case of directionally solidified dendritic microstructures, where characterizing the primary dendrite arm spacing is vital to developing the process-structure-property relationships that can lead to the design and optimization of processing routes for defined properties. In this work, four series of simulations were used to examine the capability of a few Voronoi-based techniques to capture local microstructure statistics (primary dendrite arm spacing and coordination number) in controlled (synthetically generated) microstructures. These simulations used both cubic and hexagonal microstructures with varying degrees of disorder (noise) to study the effects of length scale, base microstructure, microstructure variability, and technique parameters on the local PDAS distribution, local coordination number distribution, bulk PDAS, and bulk coordination number. The Voronoi tesselation technique with a polygon-side-length criterion correctly characterized the known synthetic microstructures. By systematically studying the different techniques for quantifying local primary dendrite arm spacings, we have evaluated their capability to capture this important microstructure feature in different dendritic microstructures, which can be an important step for experimentally correlating with both processing and properties in single crystal nickel-based superalloys.

  16. Combined No Dig techniques for the characterization of historical buildings' structural elements in Abruzzo

    NASA Astrophysics Data System (ADS)

    Ranalli, Danilo; Santacroce, Cristina

    2013-04-01

    Non destructive investigation techniques, No Dig Techniques, have been applied in engineering field since over fifty years, and their employment innovations increase proportionally to the technological development. Actually, for existing buildings, is possible to employ several non destructive investigation techniques, according to current national and local regulations. The application of an indirect survey campaign, enable to extend the result obtained by a confined e/o local destructive investigation method to the whole studied object. It offers a more complete structure knowledge, in terms of physics, chemistry and mechanical characterization, in despite of using less invasive investigation methods. In this paper the attention is pointed on structures characterization, belonging to historic and architectonic Italian heritage, using minimal impact investigation methods. The proposed method consists of the combined employing of Georadar technique, using high frequencies antennas unit, and sonic method, setting an impulsive mass centred on low frequencies. The result of this combined method, employed in the Abruzzi Region post seismic context (6th april 2009 Earthquake), are exposed treating two case-studies of masonry pillars characterization in the "De Amicis" school courtyard (L'Aquila old town centre), and in the naves of Valvense Basilica di San Pelino (Corfinio).

  17. Novel Pb(Ti, Zr)O3(PZT) Crystallization Technique Using Flash Lamp for Ferroelectric RAM (FeRAM) Embedded LSIs and One Transistor Type FeRAM Devices

    NASA Astrophysics Data System (ADS)

    Yamakawa, Koji; Imai, Keitaro; Arisumi, Osamu; Arikado, Tsunetoshi; Yoshioka, Masaki; Owada, Tatsushi; Okumura, Katsuya

    2002-04-01

    A novel method of ferroelectric capacitor formation for Ferroelectrie random access memory (FeRAM) embedded LSIs and one-transistor-type FeRAMs has been developed. Amorphous Pb(Ti, Zr)O3(PZT) films were successfully transformed to the perovskite phase by a flash lamp technique with a crystallization time of 1.2 ms at a substrate temperature of 350°C. A flash lamp energy of 27 J/cm2 was sufficient to form a ferroelectric crystal structure due to rapid thermal effects with little heat diffusion in the depth direction. This technique enabled PZT film crystallization in Pt/PZT/Pt structures on multi-Al wiring layers. Granular PZT grains were observed on Pt, Ru and RuO2 electrodes, which indicates that crystal growth begins from the film surfaces. Ferroelectric property was verified by the process at 350°C maximum temperature. PZT films were also crystallized directly on SiO2. This is useful for the fabrication of embedded FeRAM devices and 1Tr-type FeRAMs. The flash lamp process was found to have great potential for application to dielectric film formation, annealing processes and so on.

  18. Characterization techniques to validate models of density variations in pressed powder compacts

    SciTech Connect

    Garino, T.; Mahoney, M.; Readey, M.; Ewsuk, K.; Gieske, J.; Stoker, G.; Min, S.

    1995-07-01

    Techniques for characterizing density gradients generated during typical powder compaction processes are reviewed and several are evaluated. The techniques reviewed are ultrasonic velocity measurements, laser ultrasonic velocity measurements, x-ray radiography, autoradiography, computer tomography (CT), magnetic resonance imaging (MRI), and simple image analysis of polished cross-sections. Experimental results are reported for all of these techniques except autoradiography, CT and MRI. The test specimens examined were right circular cylinders of a high length/diameter ratio (to ensure significant density variation) pressed from commercial spray-dried alumina powders. Although the density gradients could be detected with all four techniques, ultrasonic velocity measurements gave the best contour map of gradients and is therefore most suitable for model validation. On the other hand, it was concluded that x-ray radiography is preferable in situations where cost and/or number of samples are more important that high resolution.

  19. In situ attosecond pulse characterization techniques to measure the electromagnetic phase

    NASA Astrophysics Data System (ADS)

    Spanner, M.; Bertrand, J. B.; Villeneuve, D. M.

    2016-08-01

    A number of techniques have been developed to characterize the attosecond emission from high-order-harmonic sources. These techniques are broadly classified as ex situ, where the attosecond pulse train photoionizes a target gas in the presence of an infrared field, and in situ, where the measurement takes place in the medium in which the attosecond pulses are generated. It is accepted that ex situ techniques measure the characteristics of the electromagnetic field, including the phase of the recombination transition moment of the emitting atom or molecule, when the phase of the second medium is known. However, there is debate about whether in situ techniques measure the electromagnetic field, or only the characteristics of the recolliding electron before recombination occurs. We show numerically that in situ measurements are not sensitive to the recombination phase, when implemented in the perturbative regime as originally envisioned, and that they do not measure the electromagnetic phase of the emission.

  20. Residual stress characterization of welds and post-weld processes using x-ray diffraction techniques

    NASA Astrophysics Data System (ADS)

    Brauss, Michael E.; Pineault, James A.; Eckersley, John S.

    1998-03-01

    This paper illustrates the importance of residual stress characterization in welds and post weld processes. The failure to characterize residual stresses created during welding and/or post weld processes can lead to unexpected occurrences of stress corrosion cracking, distortion, fatigue cracking as well as instances of over design or over processing. The development of automated residual stress mapping and the availability of portable and fast equipment have now made the characterization of residual stresses using x-ray diffraction practical for process control and optimization. The paper presents examples where x-ray diffraction residual stress characterization techniques were applied on various kinds of welds including arc welds, TIG welds, resistance welds, laser welds and electron beam welds. The nondestructive nature of the x-ray diffraction technique has made the residual stress characterization of welds a useful tool for process optimization and failure analysis, particularly since components can be measured before and after welding and post welding processes. Some examples presented show the residual stresses before and after the application of post weld processes such as shot peening, grinding and heat treatment.

  1. CODEHOP-mediated PCR – A powerful technique for the identification and characterization of viral genomes

    PubMed Central

    Rose, Timothy M

    2005-01-01

    Consensus-Degenerate Hybrid Oligonucleotide Primer (CODEHOP) PCR primers derived from amino acid sequence motifs which are highly conserved between members of a protein family have proven to be highly effective in the identification and characterization of distantly related family members. Here, the use of the CODEHOP strategy to identify novel viruses and obtain sequence information for phylogenetic characterization, gene structure determination and genome analysis is reviewed. While this review describes techniques for the identification of members of the herpesvirus family of DNA viruses, the same methodology and approach is applicable to other virus families. PMID:15769292

  2. Characterization of third-degree burned skin by nonlinear microscopy technique

    NASA Astrophysics Data System (ADS)

    dos Santos, Moisés O.; Pelegati, Vitor B.; Cesar, Carlos L.; Correa, Paulo R.; Zorn, Telma Maria T.; Zezell, Denise M.

    2011-03-01

    Nonlinear microscopy imaging technique enable take both images of collagen fibers in dermis through second harmonic generation (SHG) signal and elastic fibers by two-photon emission fluorescence microscopy (TPEFM). These techniques are the most commonly used technique for turbid and thick tissue imaging and also to image biological samples which presents highly ordered structural proteins without any exogenous label. The objective of this study is characterizing dermis of third-degree burned skin by TPEFM and SHG technique. The modelocked laser (Spectra Physics) source used in this study with pulse width of approximately 100 fs at 80 MHz was directed into a multiphoton microscope using a laser scanning unit (Olympus Fluoview 300), mounted on an inverted confocal system microscope (Olympus IX81), with focusing objective (40x, NA = 1.30). The samples were obtained from Wistar rats, male, adult. One dorsum area was submitted to burn caused by vapour exposure. The biopsies obtained were cryosectioned in slices of 20 μm width. Selected area of interface between the injured and healthy subdermal burned skin were imaged by TPEFM and SHG technique. Two different autofluorescence signals are observed as a function of excitation wavelength. The autofluorescence observed at 760 nm and 690 nm suggest components of extracellular matrix at differents depths. In SHG images, collagen fibers are visible. According to the images obtained, these methodologies can be used to characterize dermis of burned tissue as its healing process with reduced out-of-plane photobleaching and phototoxicity.

  3. Developing High-Frequency Quantitative Ultrasound Techniques to Characterize Three-Dimensional Engineered Tissues

    NASA Astrophysics Data System (ADS)

    Mercado, Karla Patricia E.

    Tissue engineering holds great promise for the repair or replacement of native tissues and organs. Further advancements in the fabrication of functional engineered tissues are partly dependent on developing new and improved technologies to monitor the properties of engineered tissues volumetrically, quantitatively, noninvasively, and nondestructively over time. Currently, engineered tissues are evaluated during fabrication using histology, biochemical assays, and direct mechanical tests. However, these techniques destroy tissue samples and, therefore, lack the capability for real-time, longitudinal monitoring. The research reported in this thesis developed nondestructive, noninvasive approaches to characterize the structural, biological, and mechanical properties of 3-D engineered tissues using high-frequency quantitative ultrasound and elastography technologies. A quantitative ultrasound technique, using a system-independent parameter known as the integrated backscatter coefficient (IBC), was employed to visualize and quantify structural properties of engineered tissues. Specifically, the IBC was demonstrated to estimate cell concentration and quantitatively detect differences in the microstructure of 3-D collagen hydrogels. Additionally, the feasibility of an ultrasound elastography technique called Single Tracking Location Acoustic Radiation Force Impulse (STL-ARFI) imaging was demonstrated for estimating the shear moduli of 3-D engineered tissues. High-frequency ultrasound techniques can be easily integrated into sterile environments necessary for tissue engineering. Furthermore, these high-frequency quantitative ultrasound techniques can enable noninvasive, volumetric characterization of the structural, biological, and mechanical properties of engineered tissues during fabrication and post-implantation.

  4. Development and application of techniques for the microstructural characterization of hydrogen permeability in zirconium oxides

    NASA Astrophysics Data System (ADS)

    Glavicic, Michael G.

    Equipment and techniques have been developed for the microstructural characterization of Zirconium Oxide films grown on Zr-2.5%Nb pressure tubes. A thin film texture apparatus was constructed and used to measure the texture and stress present in thin zirconium oxide films. The general techniques developed employ a grazing incidence geometry which allows the texture and stress present in thin films (<1mum) of any type to be examined. In addition, a technique for the quantitative phase analysis of textured ZrO2 films grown on zirconium alloys using pole figure data has also been developed. Moreover, equipment was constructed to determine the relative porosity of oxide films grown on a metal substrate using an electrochemical method that measures the effective non-porous oxide thickness. The described equipment and techniques were then used to characterize a test matrix of specimens whose relative hydrogen pick-up was measured by Differential Scanning Calorimetry. The application of beat treatments to the substrates prior to oxide growth was found to have a pronounced effect upon the sharpness of the oxide texture. A correlation between the degree of sharpness of the oxide texture and hydrogen pick-up and corrosion rate of the substrate was also determined. In addition, based upon the new techniques developed it was determined that the tetragonal phase of the oxide is stress stabilized in a region close to the metal/oxide interface.

  5. Characterization of Terahertz Single-Photon-Sensitive Bolometric Detectors Using a Pulsed Microwave Technique

    SciTech Connect

    Santavicca, D. F.; Frunzio, L.; Prober, D. E.; Reulet, B.; Karasik, B. S.; Pereverzev, S. V.; Olaya, D.; Gershenson, M. E.

    2009-12-16

    We describe a technique for characterizing bolometric detectors that have sufficient sensitivity to count single terahertz photons. The device is isolated from infrared blackbody radiation and a single terahertz photon is simulated by a fast microwave pulse, where the absorbed energy of the pulse is equal to the photon energy. We have employed this technique to characterize bolometric detectors consisting of a superconducting titanium nanobridge with niobium contacts. Present devices have T{sub c} = 0.3 K and a measured intrinsic energy resolution of approximately 6 terahertz full-width at half-maximum, near the predicted value due to intrinsic thermal fluctuation noise, with a time constant of 2 {mu}s. An intrinsic energy resolution of 1 terahertz should be achievable by reducing the volume of the titanium nanobridge. Such a detector has important applications in future space-based terahertz astronomy missions.

  6. Three-dimensional microstructural characterization of bulk plutonium and uranium metals using focused ion beam technique

    NASA Astrophysics Data System (ADS)

    Chung, Brandon W.; Erler, Robert G.; Teslich, Nick E.

    2016-05-01

    Nuclear forensics requires accurate quantification of discriminating microstructural characteristics of the bulk nuclear material to identify its process history and provenance. Conventional metallographic preparation techniques for bulk plutonium (Pu) and uranium (U) metals are limited to providing information in two-dimension (2D) and do not allow for obtaining depth profile of the material. In this contribution, use of dual-beam focused ion-beam/scanning electron microscopy (FIB-SEM) to investigate the internal microstructure of bulk Pu and U metals is demonstrated. Our results demonstrate that the dual-beam methodology optimally elucidate microstructural features without preparation artifacts, and the three-dimensional (3D) characterization of inner microstructures can reveal salient microstructural features that cannot be observed from conventional metallographic techniques. Examples are shown to demonstrate the benefit of FIB-SEM in improving microstructural characterization of microscopic inclusions, particularly with respect to nuclear forensics.

  7. Thermal characterization and tomography of carbon fiber reinforced plastics using individual identification technique

    SciTech Connect

    Vavilov, V.P.; Grinzato, E.; Bison, P.G.; Marinetti, S.; Bressan, C.

    1996-05-01

    A method for thermal characterization of defect depth and thickness using individual inversion functions is described. Experimental results are obtained with standard carbon fiber reinforced plastic specimens which contained Teflon inserts and impact damage. Accuracy in determining defect dimensions was about 10 percent for defect depth and 33 percent for defect thickness. A technique to synthesize images of defect parameters is proposed. Thermal tomography advantages in analyzing defect in-depth propagation are illustrated.

  8. In Situ Mechanical Testing Techniques for Real-Time Materials Deformation Characterization

    NASA Astrophysics Data System (ADS)

    Rudolf, Chris; Boesl, Benjamin; Agarwal, Arvind

    2016-01-01

    In situ mechanical property testing has the ability to enhance quantitative characterization of materials by revealing the occurring deformation behavior in real time. This article will summarize select recent testing performed inside a scanning electron microscope on various materials including metals, ceramics, composites, coatings, and 3-Dimensional graphene foam. Tensile and indentation testing methods are outlined with case studies and preliminary data. The benefits of performing a novel double-torsion testing technique in situ are also proposed.

  9. Ultrasonic wave techniques and characterization of filled elastomers and biodegradable polymers

    NASA Astrophysics Data System (ADS)

    Wu, Hsueh-Chang

    Ultrasonic wave technique is an excellent method for non-destructive testing and for the monitoring of polymer curing, fatigue damage and polymer transition. It is also a potentially effective tool to be applied in the characterization of high frequency viscoelastic properties of polymers. This research represents the effort to improve and further develop ultrasonic wave techniques and extend its applications to new material evaluation areas. The work is presented as followings: In chapter 1, the fundamental wave propagation theories and characterization of the viscoelastic properties of materials by acoustic parameters were briefly reviewed. In chapter 2, the effects of carbon black filler on the elastomers were studied by the longitudinal wave pulse-echo technique. It is found that the enhanced pulse-echo technique is able to characterize the effects of polymer base, filler loading level, type as well as temperature, on the acoustic properties of filled elastomers. In chapter 3, the application of longitudinal wave pulse-echo technique was extended to the monitoring of the degradation process of biodegradable polymers: poly (glycolic acid)(PGA), poly (lactic acid) (PLA) and their copolymer-poly(d,l-lactide-co-glycolide) (PDLLG). It shows that the pulse-echo technique is able to differentiate the effects of polymer structure and preparation method on the degradation behavior of biopolymers. In chapter 4, the Young's modulus, shear modulus, bulk modulus and Poisson ratio of carbon black filled elastomers were determined by the longitudinal wave pulse-echo method and the shear wave through-transmission method. The effects of polymer base, filler loading and dispersion on the elastomers were also studied by the calculated elastic constants. In chapter 5, the effects of carbon black filler on the elastomers were studied by an innovative calibrated longitudinal and shear wave surface impedance technique. The results show that the effects of polymer base, filler loading

  10. Wave Propagation Due to an Embedded Seismic Source in a Graded Half-Plane with Relief Peculiarities Part I: Mechanical Model and Computational Technique

    NASA Astrophysics Data System (ADS)

    Fontara, I.-K.; Wuttke, F.; Parvanova, S.; Dineva, P.

    2015-03-01

    This work addresses the evaluation of the seismic wave field in a graded half-plane with free-surface and/or sub-surface relief subjected to shear horizontally (SH)-polarized wave, radiating from an embedded seismic source. The considered boundary value problem is transformed into a system of boundary integral equations (BIEs) along the boundaries of the free-surface and of any sub-surface relief, using an analytically derived frequency-dependent Green's function for a quadratically inhomogeneous in depth half-plane. The numerical solution yields synthetic seismic signals at any point of the half-plane in both frequency and time domain following application of Fast Fourier Transform (FFT). Finally, in the companion paper, the verification and numerical simulation studies demonstrate the accuracy and efficiency of the present computational approach. The proposed BIE tool possesses the potential to reveal the sensitivity of the seismic signal to the type and properties of the seismic source, to the existence and type of the material gradient and to the lateral inhomogeneity, due to the free-surface and/or sub-surface relief peculiarities.

  11. Isolation, Identification, and Characterization of One Degradation Product in Ambroxol by HPLC-Hyphenated Techniques

    PubMed Central

    Thummala, Veera Raghava Raju; Ivaturi, Mrutyunjaya Rao; Nittala, Someswara Rao

    2014-01-01

    This study details the isolation, identification, and characterization of ambroxol’s unknown impurity. One unknown impurity of ambroxol was formed in the formulated drug under stress conditions [40°C /75% relative humidity (RH) for 6 months] with the relative retention time (RRT) 0.68 in RP-HPLC. The impurity was enriched by exposing it to heat and it was isolated by using preparative HPLC. The enriched impurity was purified and characterized using the following sophisticated techniques: 2D NMR (gDQ-COSY, gHSQC, and gHMBC), FTIR, and LC-MS/MS. On the basis of the spectral data, the impurity was characterized as trans-4-(6,8-dibromoquinazolin-3(4H)-yl)cyclohexanol. PMID:24959402

  12. Site and Event Characterization Using the CTBT On-Site Inspection Techniques (Invited)

    NASA Astrophysics Data System (ADS)

    Labak, P.; Gaya Pique, L. R.; Rowlands, A. P.; Arndt, R. H.

    2013-12-01

    One of the four elements of the CTBT verification regime is On-Site Inspection (OSI). The sole purpose of an OSI is to clarify whether a nuclear weapon test explosion or any other nuclear explosion has been conducted in violation of the CTBT. An OSI would be conducted within an area no bigger than 1000 km2 and by no more than 40 inspectors at any one time, applying search logic and inspection techniques with the aim of collecting relevant information that will be the basis for the inspection report. During the course of an OSI less intrusive techniques applied over broad areas (usually with lower spatial resolution) are supplemented with more intrusive techniques applied to more targeted areas (usually at a higher spatial resolution). Environmental setting and the evolution of OSI-relevant observables over time will influence the application of OSI techniques. In the course of the development of OSI methodology and relevant techniques, field tests and exercises have been conducted. While earlier activities mainly focused on progress of individual techniques (such as visual observation, passive seismological monitoring for aftershocks and measurements of radioactivity), recent work covered both technique development (such as multi-spectral imaging including infrared measurements, and environmental sampling and analysis of solids, liquids and gases) as well as the integration of techniques, search logic and data flow. We will highlight examples of application of OSI technologies for site and event characterization from recently conducted field tests and exercises and demonstrate the synthesis of techniques and data necessary for the conduct of an OSI.

  13. Experimental source characterization techniques for studying the acoustic properties of perforates under high level acoustic excitation.

    PubMed

    Bodén, Hans

    2011-11-01

    This paper discusses experimental techniques for obtaining the acoustic properties of in-duct samples with non-linear acoustic characteristic. The methods developed are intended both for studies of non-linear energy transfer to higher harmonics for samples only accessible from one side such as wall treatment in aircraft engine ducts or automotive exhaust systems and for samples accessible from both sides such as perforates or other top sheets. When harmonic sound waves are incident on the sample nonlinear energy transfer results in sound generation at higher harmonics at the sample (perforate) surface. The idea is that these sources can be characterized using linear system identification techniques similar to one-port or two-port techniques which are traditionally used for obtaining source data for in-duct sources such as IC-engines or fans. The starting point will be so called polyharmonic distortion modeling which is used for characterization of nonlinear properties of microwave systems. It will be shown how acoustic source data models can be expressed using this theory. Source models of different complexity are developed and experimentally tested. The results of the experimental tests show that these techniques can give results which are useful for understanding non-linear energy transfer to higher harmonics. PMID:22087890

  14. Characterization of hard coatings produced by laser cladding using laser-induced breakdown spectroscopy technique

    NASA Astrophysics Data System (ADS)

    Varela, J. A.; Amado, J. M.; Tobar, M. J.; Mateo, M. P.; Yañez, A.; Nicolas, G.

    2015-05-01

    Protective coatings with a high abrasive wear resistance can be obtained from powders by laser cladding technique, in order to extend the service life of some industrial components. In this work, laser clad layers of self-fluxing NiCrBSi alloy powder mixed with WC powder have been produced on stainless steel substrates of austenitic type (AISI 304) in a first step and then chemically characterized by laser-induced breakdown spectroscopy (LIBS) technique. With the suitable laser processing parameters (mainly output power, beam scan speed and flow rate) and powders mixture proportions between WC ceramics and NiCrBSi alloys, dense pore free layers have been obtained on single tracks and on large areas with overlapped tracks. The results achieved by LIBS technique and applied for the first time to the analysis of laser clads provided the chemical composition of the tungsten carbides in metal alloy matrix. Different measurement modes (multiple point analyses, depth profiles and chemical maps) have been employed, demonstrating the usefulness of LIBS technique for the characterization of laser clads based on hardfacing alloys. The behavior of hardness can be explained by LIBS maps which evidenced the partial dilution of some WC spheres in the coating.

  15. Damage characterization in engineering materials using a combination of optical, acoustic, and thermal techniques

    NASA Astrophysics Data System (ADS)

    Tragazikis, I. K.; Exarchos, D. A.; Dalla, P. T.; Matikas, T. E.

    2016-04-01

    This paper deals with the use of complimentary nondestructive methods for the evaluation of damage in engineering materials. The application of digital image correlation (DIC) to engineering materials is a useful tool for accurate, noncontact strain measurement. DIC is a 2D, full-field optical analysis technique based on gray-value digital images to measure deformation, vibration and strain a vast variety of materials. In addition, this technique can be applied from very small to large testing areas and can be used for various tests such as tensile, torsion and bending under static or dynamic loading. In this study, DIC results are benchmarked with other nondestructive techniques such as acoustic emission for damage localization and fracture mode evaluation, and IR thermography for stress field visualization and assessment. The combined use of these three nondestructive methods enables the characterization and classification of damage in materials and structures.

  16. A new technique of characterization of intrapixel response dedicated to astronomical detectors

    NASA Astrophysics Data System (ADS)

    Ketchazo, C.; Viale, T.; Boulade, O.; Druart, G.; Moreau, V.; Mugnier, L.; Dubrueil, D.; Derelle, S.; Ronayette, S.; Guérineau, N.; Berthé, M.

    2015-07-01

    This paper is devoted to the presentation of a new technique of characterization of the intra-pixel sensitivity variations (IPSVs) of astronomical detectors. The IPSV is the spatial variation of the pixel response function (PRF). In the case of under-sampled instruments for high quality imaging and accurate photometry, IPSV can contribute to the instrument global error and it should be considered carefully. Our measurement technique is based in the Fourier transform (FT) approach. It consists into the sampling of the pixel transfer function (PTF) by projecting high-resolution periodic patterns onto the whole sensor without classic optics but using the self-imaging property (the Talbot effect) of a continuously self imaging grating (CSIG) illuminated by a plane wave. The PRF is determined by computing the inverse FT. Our measurement technique permits to determine the PRF with a resolution of pixel/10 (10 times Nyquist frequency).

  17. Parametric techniques for characterizing myocardial tissue by magnetic resonance imaging (part 1): T1 mapping.

    PubMed

    Perea Palazón, R J; Ortiz Pérez, J T; Prat González, S; de Caralt Robira, T M; Cibeira López, M T; Solé Arqués, M

    2016-01-01

    The development of myocardial fibrosis is a common process in the appearance of ventricular dysfunction in many heart diseases. Magnetic resonance imaging makes it possible to accurately evaluate the structure and function of the heart, and its role in the macroscopic characterization of myocardial fibrosis by late enhancement techniques has been widely validated clinically. Recent studies have demonstrated that T1-mapping techniques can quantify diffuse myocardial fibrosis and the expansion of the myocardial extracellular space in absolute terms. However, further studies are necessary to validate the usefulness of this technique in the early detection of tissue remodeling at a time when implementing early treatment would improve a patient's prognosis. This article reviews the state of the art for T1 mapping of the myocardium, its clinical applications, and its limitations. PMID:26944850

  18. A novel optical technique to characterize fiberization of textured vegetable proteins under high-moisture extrusion

    NASA Astrophysics Data System (ADS)

    Yao, Gang; Liu, Keshun; Hsieh, Fu-Hung

    2004-11-01

    There have been great interests in using twin-screw extruders under high moisture conditions to produce textured vegetable proteins. Unlike the low moisture extrusion counterpart, a product extruded under high moisture can have well-defined fiber orientation and bears a strong resemblance to muscle meat. The textural properties of such extruded products are important for consumer acceptance. In this study, we developed a novel fluorescence polarization based technique that measures the fiber formation of extruded protein products. The experimental results using our new technique showed good agreements with results obtained from visual inspection and digital imaging of the dissected samples. The new technique provides an in vivo and noninvasive approach to characterize the fiber formation of textured vegetable proteins under high moisture extrusion. It has a potential to be used as a real time monitoring tool in food extrusion studies.

  19. X-ray Scattering Techniques for Characterization of Nanosystems in Lifescience

    SciTech Connect

    Saw, C K

    2005-04-11

    The intent of this chapter is to provide the basics of using x-ray diffraction techniques in order to obtain information on the structure and morphology of the nanosystems, and also to point out some of its strengths and weaknesses when compare to other characterization techniques. X-ray scattering examines over a wide range of density domains from a tenth to a thousandth angstrom. Essentially, this covers a whole range of condensed matter, including the structure and morphology of nanosystems, particularly useful for examining nanostructures in lifescience. This range of domain size requires both the wide-angle x-ray scattering (WAXS) and small-angle (SAXS) x-ray scattering techniques. Roughly WAXS covers from 2 nm down, and SAXS covers from .5 nm to 100 nm and possibly 1,000 nm for a finely tuned instrument. Brief theoretical description of both WAXS and SAXS will be given in this chapter. WAXS, by itself is a powerful technique in providing information on the crystallographic structure or lack of structure, atomic positions and sizes in a unit cell, to some extend, chemical compositions and as well as chemical stoichiometry. Examples of such experiments will also be given. In order to be able to describe the technique of x-ray scattering, some historical and theoretical background will be given in the hope of making this subject interesting and simple.

  20. A Study of undulator magnets characterization using the Vibrating Wire technique

    SciTech Connect

    Temnykh, Alexander; Levashov, Yurii; Wolf, Zachary; /SLAC

    2011-02-07

    The vibrating wire (VW) technique employs a stretched wire as a magnetic field sensor. Because of the wire's small diameter ({approx}0.1mm or smaller) and because the wire can be supported from outside the magnet, this technique is very appealing for field measurements in small gap/bore undulators with small good field regions and with limited access to the tested field. In addition, in the case of elliptical undulators in which Hall probe (HP) measurements can be affected by the planar Hall effect, VW technique can be used as an independent method to verify and supplement HP measurements. In this article we studied the potential of the VW technique for measurement of magnetic field errors and for prediction of beam trajectories in undulator magnets using a 3.8m long LCLS undulator as a test bench. Introducing calibrated magnetic field distortion at various locations, we measured the sensitivity and spatial resolution of the method. The method demonstrated 0.9mm spatial resolution at a distance up to a few meters and 0.37Gcm sensitivity to the field integral. To compare Hall probe and Vibrating wire measurements side-by-side, we measured field errors in an LCLS undulator previously characterized by Hall probe measurements. The field errors found with the Vibrating Wire technique appeared to be in good agreement with errors measured with the Hall probe. Beam trajectory distortions calculated from both data sets are also in a good agreement.

  1. Experimental techniques for characterizing the thermo-electro-mechanical shakedown response of SMA wires and tubes

    NASA Astrophysics Data System (ADS)

    Churchill, Christopher B.

    Shape Memory Alloys (SMAs) are a unique and valuable group of active materials. NiTi, the most popular SMA, has a power density orders of magnitude greater than any other known material, making it valuable in the medical and transportation industries where weight and space are at a premium. In the nearly half-century since its discovery, the adoption of NiTi has been slowed primarily by the engineering difficulties associated with its use: strong thermal coupling, material level instabilities, and rapid shakedown of material properties during cycling. Material properties change drastically with minute changes in alloy composition, so it is common to require a variety of experiments to fully characterize a new SMA material, all of which must be performed and interpreted with specialized techniques. This thesis collects many of these techniques into a series of characterization experiments, documenting several new phenomena in the process. First, three different alloys of NiTi wire are characterized through differential scanning calorimetry, isothermal tension, and constant load thermal cycling experiments. New techniques are presented for ER measurement and temperature control of SMA wires and temperature measurement of SMA tubes. It is shown that the shakedown of material properties with thermal cycling is not only dependent on the applied load and number of cycles, but has a large association with the direction of phase transformation. Several of these techniques are then applied to a systematic characterization of NiTi tubes in tension, compression, and bending. Particular attention is given to the nucleation and propagation of transformation fronts in tensile specimens. Compression experiments show dramatic asymmetry in the uniaxial response, with compression characterized by a lower transformation strain, higher transformation stress, and uniform transformations (no fronts). A very simple SMA actuator model is introduced. After identifying the relevant non

  2. X-ray wavefront characterization using a rotating shearing interferometer technique.

    PubMed

    Wang, Hongchang; Sawhney, Kawal; Berujon, Sébastien; Ziegler, Eric; Rutishauser, Simon; David, Christian

    2011-08-15

    A fast and accurate method to characterize the X-ray wavefront by rotating one of the two gratings of an X-ray shearing interferometer is described and investigated step by step. Such a shearing interferometer consists of a phase grating mounted on a rotation stage, and an absorption grating used as a transmission mask. The mathematical relations for X-ray Moiré fringe analysis when using this device are derived and discussed in the context of the previous literature assumptions. X-ray beam wavefronts without and after X-ray reflective optical elements have been characterized at beamline B16 at Diamond Light Source (DLS) using the presented X-ray rotating shearing interferometer (RSI) technique. It has been demonstrated that this improved method allows accurate calculation of the wavefront radius of curvature and the wavefront distortion, even when one has no previous information on the grating projection pattern period, magnification ratio and the initial grating orientation. As the RSI technique does not require any a priori knowledge of the beam features, it is suitable for routine characterization of wavefronts of a wide range of radii of curvature. PMID:21935019

  3. Propagation or failure of detonation across an air gap in an LX-17 column: continuous time-dependent detonation or shock speed using the Embedded Fiber Optic (EFO) technique

    SciTech Connect

    Hare, D E; Chandler, J B; Compton, S M; Garza, R G; Grimsley, D A; Hernandez, A; Villafana, R J; Wade, J T; Weber, S R; Wong, B M; Souers, P C

    2008-01-16

    The detailed history of the shock/detonation wave propagation after crossing a room-temperature-room-pressure (RTP) air gap between a 25.4 mm diameter LX-17 donor column and a 25.4 mm diameter by 25.4 mm long LX-17 acceptor pellet is investigated for three different gap widths (3.07, 2.08, and 0.00 mm) using the Embedded Fiber Optic (EFO) technique. The 2.08 mm gap propagated and the 3.07 mm gap failed and this can be seen clearly and unambiguously in the EFO data even though the 25.4 mm-long acceptor pellet would be considered quite short for a determination by more traditional means such as pins.

  4. Characterizing surface features on conducting specimens through an insulation layer using the capacitive imaging technique

    NASA Astrophysics Data System (ADS)

    Li, Zhen; Yin, Xiaokang; Yan, An; Li, Wei; Chen, Guoming

    2016-02-01

    Capacitive imaging (CI) technique is a novel electromagnetic NDE technique. It uses a carefully designed probe with a pair of metal electrodes. Interaction between the Quasi-static electromagnetic field from the electrode pair and the testing material causes changes in signal when the electrical properties of the sample themselves change, leading to the possibility of imaging. Due to its capacitive nature, the CI technique requires single side non-contact access to the testing material and little sample surface preparation. In addition, it provides a very clear and simple defect indication. Previous work [1] has demonstrated the feasibility of the CI technique to the detection of surface features on conducting specimens. It is found that the CI technique is useful to confirm the presence of a defect but cannot further characterize it due to the "blurring effect". The problem caused by the blurring effect is more significant, when trying to image smaller feature though a thicker insulation layer (comparing to the dimensions of the CI probe). This paper aims to tackle this problem using a two dimensional deconvolution method based on the analysis of the measurement sensitivity distribution. In this paper, the trade-offs between penetration depth, signal strength and imaging resolution of the CI technique are discussed. The blurring effect due to the CI probe geometry is explained. The proposed method to retrieve the real shape of the feature is then described in details, and its feasibility is also demonstrated. The results indicated that the CI technique could be useful to detect Corrosion Under Insulation (CUI).

  5. Region-growing technique adapted to precise microcalcification characterization in mammography

    NASA Astrophysics Data System (ADS)

    Darboux, Michel; Dinten, Jean-Marc; Nicolas, Eric

    1996-11-01

    The early detection of breast cancer is essential for increasing the survival rate of the disease. Today, mammography is the only breast screening technique capable of detecting breast cancer at a very early stage. The presence of a breast tumor is indicated by some features on the mammogram. One sign of malignancy is the presence of clusters of fine, granular microcalcifications. We present here a three-step method for detecting and characterizing these microcalcifications. We begin with the detection of potential candidates. The aim of this first step is to detect all the pixels that could be a microcalcification. Then we focus on our specific region growing technique which provides an accurate extraction of the shape of the region corresponding to each detected growing technique which provides an accurate extraction of the shape of the region corresponding to each detected seed. This second step is essential because microcalcifications shape is a very important feature for the diagnosis. It is then possible to determine precise parameters to characterize these microcalcifications. This three-step method has been evaluated on a set of images form the mammographic image analysis society database.

  6. Secondary side photographic techniques used in characterization of Surry steam generator

    SciTech Connect

    Sinclair, R.B.

    1984-10-01

    Characterization of the generator's secondary side prior to destructive removal of tubing presents a significant challenge. Information must be obtained in a radioactive field (up to 15 R/h) throughout the tightly spaced bundle of steam generator tubes. This report discusses the various techniques employed, along with their respective advantages and disadvantages. The most successful approach to nondestructive secondary side characterization and documentation was through use of in-house developed pinhole cameras. These devices provided accurate photographic documentation of generator condition. They could be fabricated in geometries allowing access to all parts of the generator. Semi-remote operation coupled with large area coverage per investigation and short at-location times resulted in significant personnel exposure advantages. The fabrication and use of pinhole cameras for remote inspection is discussed in detail.

  7. Spatial and vectorial characterization of thermal relaxation using the spin-stand imaging technique

    NASA Astrophysics Data System (ADS)

    Tse, C.; Mircea, D. I.; Mayergoyz, I. D.; Andrei, P.; Krafft, C.

    2002-05-01

    The spatial and vectorial characterization of thermal relaxation of recorded magnetization patterns by using the spin-stand imaging technique [I. D. Mayergoyz et al., J. Appl. Phys. 87, 6824 (2000); 89, 6772 (2001)] is reported. In order to obtain such characterization, a recorded track is scanned at successive instants of time over periods of 70 hours. As a result, the spatial distributions of the read-back voltages (that constitute the "raw" images of the track) are consecutively collected. The images of the vectorial magnetization are then reconstructed and local magnetization relaxation rates are subsequently evaluated. It is demonstrated that the spatially inhomogeneous and vectorial nature of thermal relaxation of recorded patterns may result in temporal track broadening. It is found that this temporal track broadening is more pronounced for disks with higher coercivities.

  8. Spectroscopic techniques applied to the characterization of decorated potteries from Caltagirone (Sicily, Italy)

    NASA Astrophysics Data System (ADS)

    Barilaro, D.; Barone, G.; Crupi, V.; Donato, M. G.; Majolino, D.; Messina, G.; Ponterio, R.

    2005-06-01

    The aim of the present work is the characterization of decorated pottery samples from Caltagirone (Sicily, Italy), a renowned production centre of this kind of artwork. These fragments were found during archaeological excavations and were attributed to historical periods extremely far in time from each other (from XVIII century b.C. to XVI a.C.). Therefore, we expect that the manufacture techniques result rather different over so long time. The measurements, performed by Fourier Transform-InfraRed (FT-IR) absorbance and micro-Raman scattering, allowed us a non-destructive study of so precious artefacts. Some pigments were identified, various elements of ceramic paste and glazed layer were characterized.

  9. Materials Characterization Challenges for the Semiconductor Industry: Physical and Chemical Techniques

    NASA Astrophysics Data System (ADS)

    Shaffner, Thomas J.

    2002-03-01

    Materials and device characterization serve the essential role of defining how an integrated circuit differs from its intended design and function. Over the years, a variety of physical and chemical techniques based on probes of electrons, ions and photons have evolved to fill this need. Each has a specialized application for resolving specific problems related to smaller geometry, thin film composition, and shallow junction profiling. As we enter the internet era, demands for higher speed, reliability and performance from both silicon and compound semiconductor materials and circuits is prematurely pushing sophisticated and costly R&D characterization tools closer to the manufacturing environment. This review illustrates how this is happening with emphasis on new developments in electron microscopy, ion backscattering, scanning probe methodologies, and even futuristic methods, such as the position-sensitive atom probe.

  10. Monitoring the stress build-up in dental cements: a novel optical characterization technique

    NASA Astrophysics Data System (ADS)

    Ottevaere, Heidi; Tabak, M.; Bartholomees, F.; de Wilde, Willy P.; Veretennicoff, Irina P.; Thienpont, Hugo

    2001-01-01

    It is well known that during the curing of dental cements, polymerization shrinkage induces unacceptable stresses, which can result into cracks and an over-sensitivity of the teeth. We demonstrate that polarimetric optical fiber sensors can be used to characterize this shrinkage quantitatively. To determine the time evolution and the amount of shrinkage we embed a highly birefringent optical fiber in the dental cement and analyze the change in optical polarization at its output. This change is a measure for the dynamic stress-build up. We also demonstrate the repeatability of our characterization method for these cements. Moreover we given indications that this technique allows for in- vivo monitoring of the stress build-up dynamics between dentine and porcelain facings. This may bring durable all-ceramic restorations closer to reality. In this paper we present the principle of this original optical fiber sensor, its practical implementation and the experimental results we obtained for this application.

  11. Closing the gap: accelerating the translational process in nanomedicine by proposing standardized characterization techniques

    PubMed Central

    Khorasani, Ali A; Weaver, James L; Salvador-Morales, Carolina

    2014-01-01

    On the cusp of widespread permeation of nanomedicine, academia, industry, and government have invested substantial financial resources in developing new ways to better treat diseases. Materials have unique physical and chemical properties at the nanoscale compared with their bulk or small-molecule analogs. These unique properties have been greatly advantageous in providing innovative solutions for medical treatments at the bench level. However, nanomedicine research has not yet fully permeated the clinical setting because of several limitations. Among these limitations are the lack of universal standards for characterizing nanomaterials and the limited knowledge that we possess regarding the interactions between nanomaterials and biological entities such as proteins. In this review, we report on recent developments in the characterization of nanomaterials as well as the newest information about the interactions between nanomaterials and proteins in the human body. We propose a standard set of techniques for universal characterization of nanomaterials. We also address relevant regulatory issues involved in the translational process for the development of drug molecules and drug delivery systems. Adherence and refinement of a universal standard in nanomaterial characterization as well as the acquisition of a deeper understanding of nanomaterials and proteins will likely accelerate the use of nanomedicine in common practice to a great extent. PMID:25525356

  12. Characterization of failure modes in deep UV and deep green LEDs utilizing advanced semiconductor localization techniques.

    SciTech Connect

    Tangyunyong, Paiboon; Miller, Mary A.; Cole, Edward Isaac, Jr.

    2012-03-01

    We present the results of a two-year early career LDRD that focused on defect localization in deep green and deep ultraviolet (UV) light-emitting diodes (LEDs). We describe the laser-based techniques (TIVA/LIVA) used to localize the defects and interpret data acquired. We also describe a defect screening method based on a quick electrical measurement to determine whether defects should be present in the LEDs. We then describe the stress conditions that caused the devices to fail and how the TIVA/LIVA techniques were used to monitor the defect signals as the devices degraded and failed. We also describe the correlation between the initial defects and final degraded or failed state of the devices. Finally we show characterization results of the devices in the failed conditions and present preliminary theories as to why the devices failed for both the InGaN (green) and AlGaN (UV) LEDs.

  13. NanoXCT—A High-Resolution Technique For TSV Characterization

    NASA Astrophysics Data System (ADS)

    Niese, Sven; Krueger, Peter; Zschech, Ehrenfried

    2011-09-01

    Lab-based Transmission X-ray Microscopy and X-ray Computed Tomography (TXM/XCT) with sub-100 nm resolution are evaluated for their application in process and quality control in microelectronics, particularly for TSV characterization. These are the techniques of choice to localize defects in copper TSVs for 3D IC integration. In contrast to other techniques like Focused Ion Beam cross-sectioning and subsequent Scanning Electron Microscopy imaging, the region of interest, i.e. the TSV, is imaged nondestructively and three dimensionally. For flat samples like thinned wafers, the tilted rotational axis tomography is proposed instead of the limited angle tomography since the better in-plane resolution increases the quality of the resulting tomogram. Yield- and reliability-limiting processes in 3D TSV technology like voids and incomplete filled vias can be made visible for an array of adjacent TSVs during one measurement without affecting the TSV.

  14. NanoXCT - A High-Resolution Technique For TSV Characterization

    SciTech Connect

    Niese, Sven; Krueger, Peter; Zschech, Ehrenfried

    2011-09-12

    Lab-based Transmission X-ray Microscopy and X-ray Computed Tomography (TXM/XCT) with sub-100 nm resolution are evaluated for their application in process and quality control in microelectronics, particularly for TSV characterization. These are the techniques of choice to localize defects in copper TSVs for 3D IC integration. In contrast to other techniques like Focused Ion Beam cross-sectioning and subsequent Scanning Electron Microscopy imaging, the region of interest, i.e. the TSV, is imaged nondestructively and three dimensionally. For flat samples like thinned wafers, the tilted rotational axis tomography is proposed instead of the limited angle tomography since the better in-plane resolution increases the quality of the resulting tomogram. Yield- and reliability-limiting processes in 3D TSV technology like voids and incomplete filled vias can be made visible for an array of adjacent TSVs during one measurement without affecting the TSV.

  15. Evaluation of remote sensing and automatic data techniques for characterization of wetlands. [Atchafalaya River Basin, Louisiana

    NASA Technical Reports Server (NTRS)

    Cartmill, R. H.

    1974-01-01

    This investigation has been conducted in the Atchafalaya River Basin of South Central Louisiana. This is a humid area of heavily forested swamps with a large volume of flow mostly from a diversion of the lower Mississippi River. Techniques to obtain enlarged imagery from computer compatible tapes of ERTS data without photographic enlargement is explained and illustrated. Techniques of extraction of environmental information from single bands and multiband pattern recognition procedures are explained and evaluated. A comparison of pattern recognition classifications of the Atchafalaya Basin by aircraft multispectral scanner and ERTS MSS data is made. Data for this comparison were gathered within three weeks of each other in the winter of 1973. Scorecards of the accuracy of the classifications are presented. Recommendations are made concerning the utilization of each sensor platform to perform specific tasks of wetlands characterization.

  16. Design and optimization of stepped austempered ductile iron using characterization techniques

    SciTech Connect

    Hernández-Rivera, J.L.; Garay-Reyes, C.G.; Campos-Cambranis, R.E.; Cruz-Rivera, J.J.

    2013-09-15

    Conventional characterization techniques such as dilatometry, X-ray diffraction and metallography were used to select and optimize temperatures and times for conventional and stepped austempering. Austenitization and conventional austempering time was selected when the dilatometry graphs showed a constant expansion value. A special heat color-etching technique was applied to distinguish between the untransformed austenite and high carbon stabilized austenite which had formed during the treatments. Finally, it was found that carbide precipitation was absent during the stepped austempering in contrast to conventional austempering, on which carbide evidence was found. - Highlights: • Dilatometry helped to establish austenitization and austempering parameters. • Untransformed austenite was present even for longer processing times. • Ausferrite formed during stepped austempering caused important reinforcement effect. • Carbide precipitation was absent during stepped treatment.

  17. A comparison of conventional and advanced ultrasonic inspection techniques in the characterization of TMC materials

    NASA Astrophysics Data System (ADS)

    Holland, Mark R.; Handley, Scott M.; Miller, James G.; Reighard, Mark K.

    Results obtained with a conventional ultrasonic inspection technique as well as those obtained with more advanced ultrasonic NDE methods in the characterization of an 8-ply quasi-isotropic titanium matrix composite (TMC) specimen are presented. Images obtained from a conventional ultrasonic inspection of TMC material are compared with those obtained using more sophisticated ultrasonic inspection methods. It is suggested that the latter techniques are able to provide quantitative images of TMC material. They are able to reveal the same potential defect indications while simultaneously providing more quantitative information concerning the material's inherent properties. Band-limited signal loss and slope-of-attenuation images provide quantitative data on the inherent material characteristics and defects in TMC.

  18. A comparison of conventional and advanced ultrasonic inspection techniques in the characterization of TMC materials

    NASA Technical Reports Server (NTRS)

    Holland, Mark R.; Handley, Scott M.; Miller, James G.; Reighard, Mark K.

    1992-01-01

    Results obtained with a conventional ultrasonic inspection technique as well as those obtained with more advanced ultrasonic NDE methods in the characterization of an 8-ply quasi-isotropic titanium matrix composite (TMC) specimen are presented. Images obtained from a conventional ultrasonic inspection of TMC material are compared with those obtained using more sophisticated ultrasonic inspection methods. It is suggested that the latter techniques are able to provide quantitative images of TMC material. They are able to reveal the same potential defect indications while simultaneously providing more quantitative information concerning the material's inherent properties. Band-limited signal loss and slope-of-attenuation images provide quantitative data on the inherent material characteristics and defects in TMC.

  19. Electrical characterization and modeling of pulse-based forming techniques in RRAM arrays

    NASA Astrophysics Data System (ADS)

    Grossi, Alessandro; Zambelli, Cristian; Olivo, Piero; Miranda, Enrique; Stikanov, Valeriy; Walczyk, Christian; Wenger, Christian

    2016-01-01

    The forming process, which corresponds to the activation of the switching filament in Resistive Random Access Memory (RRAM) arrays, has a strong impact on the cells' performances. In this paper we characterize and compare different pulse forming techniques in terms of forming time, yield and cell-to-cell variability on 4 kbits RRAM arrays. Moreover, post-forming modeling during Reset operation of correctly working and over formed cells has been performed. An incremental form and verify technique, based on a sequence of trapezoidal waveforms with increasing voltages followed by a verify operation that terminates when the expected switching behavior has been achieved, showed the best results. This procedure narrows the post-forming current distribution whereas reducing the Reset switching voltage and the operative current. These advantages materialize in a better control of the cell-to-cell variability and in an overall time and energy saving at the system level.

  20. Characterization of some groups of gram-negative nonfermentative bacteria by the carbon source alkalinization technique.

    PubMed Central

    Martin, R; Riley, P S; Hollis, D G; Weaver, R E; Krichevsky, M I

    1981-01-01

    A total of 541 gram-negative nonfermentative bacterial strains comprising 26 species and unclassified groups were characterized by routine diagnostic and carbon substrate alkalinization techniques. These microorganisms were tested for the ability to cause alkalinization of a basal medium on a total of 217 substrates. We found that 58 carbon substrates had some discriminatory potential. We also performed 30 routine diagnostic tests. The results of these studies were evaluated by numerical taxonomy techniques. A cluster analysis of the results by the Jaccard coefficient method identified 30 clusters at the 45% level. We identified 39 tests that separated most of the groups. Groups of similar organisms or organisms that were difficult to identify were analyzed, and tests that were differential were identified. Because of variability within the clusters, further studies utilizing deoxyribonucleic acid-deoxyribonucleic acid homologies should be undertaken. PMID:7021587

  1. Measurement technique for in situ characterizing aberrations of projection optics in lithographic tools

    SciTech Connect

    Wang Fan; Wang Xiangzhao; Ma Mingying

    2006-08-20

    As the feature size decreases, degradation of image quality caused by wavefront aberrations of projection optics in lithographic tools has become a serious problem in the low-k1 process. We propose a novel measurement technique for in situ characterizing aberrations of projection optics in lithographic tools.Considering the impact of the partial coherence illumination, we introduce a novel algorithm that accurately describes the pattern displacement and focus shift induced by aberrations. Employing the algorithm, the measurement condition is extended from three-beam interference to two-, three-, and hybrid-beam interferences. The experiments are performed to measure the aberrations of projection optics in an ArF scanner.

  2. Application of magnetoacoustic emission technique to temper embrittlement characterization of HY-80 steel

    NASA Technical Reports Server (NTRS)

    Denale, R.; Namkung, M.; Todhunter, R. G.

    1990-01-01

    Magnetoacoustic phenomena associated with the use of the magnetoacoustic emission technique for the temper embrittlement characterization of HY-80 steel are investigated in an attempt to explain some peculiarities observed in highly embrittled HY-80 samples. In particular, attention is given to the effects of the ac magnetic field frequency and shape. The peak amplitude of the magnetoacoustic burst, which is directly related to the width of the pulse height distribution, is shown to be a critical parameter in the determination of the degree of temper embrittlement in the steel.

  3. Structural characterization of sol-gel derived oxide nanostuctures using synchrotron x-ray techniques

    NASA Astrophysics Data System (ADS)

    Sun, Tao

    Ceramic oxides possess extraordinarily rich functionalities. With the advent of nanofabrication techniques, it is now possible to grow nanostructured oxides with precise control of composition, morphology, and microstructure, which has re-vitalized the research in the field of traditional ceramics. The unexpected behavior and enhanced properties of oxide nanostructures have been extensively reported. However, knowledge about the underlying mechanisms as well as structural implications is still quite limited. Therefore, it is imperative to develop and employ sophisticated characterization tools for unraveling the structure-property relationships for oxide nanostructures. The present thesis work aims at addressing the critical issues associated with fabrication, and more importantly, structural characterization of functional oxide nanostructures. The dissertation starts with introducing the strategy for synthesizing phase-pure and highly controlled oxide nanostructures using sol-gel deposition and an innovative approach called "soft" electron beam lithography. Some specific oxides are chosen for the present study, such as BiFeO3, CoFe2O4, and SnO2, because of their scientific and technological significance. Subsequent to fabrication of tailored oxide nanostructures, advanced synchrotron x-ray scattering techniques have been applied for structural characterization. The nucleation and growth behavior of BiFeO3 thin film was investigated using in situ grazing-incidence small-angle x-ray scattering (GISAXS) technique. The results reveal that the kinetics for early-stage nuclei growth are governed by the oriented-attachment model. Moreover, the porous structures of undoped and Pd-doped semiconducting SnOx thin films were quantitatively characterized using GISAXS. By correlating the structural parameters with H2 sensitivity of SnOx films, it is found out that the microstructure of doped film is favorable for gas sensing, but it is not the major reason for the overall

  4. Upset Characterization of the PowerPC405 Hard-core Processor Embedded in Virtex-II Pro Field Programmable Gate Arrays

    NASA Technical Reports Server (NTRS)

    Swift, Gary M.; Allen, Gregory S.; Farmanesh, Farhad; George, Jeffrey; Petrick, David J.; Chayab, Fayez

    2006-01-01

    Shown in this presentation are recent results for the upset susceptibility of the various types of memory elements in the embedded PowerPC405 in the Xilinx V2P40 FPGA. For critical flight designs where configuration upsets are mitigated effectively through appropriate design triplication and configuration scrubbing, these upsets of processor elements can dominate the system error rate. Data from irradiations with both protons and heavy ions are given and compared using available models.

  5. River embankment characterization: The joint use of geophysical and geotechnical techniques

    NASA Astrophysics Data System (ADS)

    Perri, Maria Teresa; Boaga, Jacopo; Bersan, Silvia; Cassiani, Giorgio; Cola, Simonetta; Deiana, Rita; Simonini, Paolo; Patti, Salvatore

    2014-11-01

    Recent flood events in Northern Italy (particularly in the Veneto Region) have brought river embankments into the focus of public attention. Many of these embankments are more than 100 years old and have been repeatedly repaired, so that detailed information on their current structure is generally missing. The monitoring of these structures is currently based, for the most part, on visual inspection and localized measurements of the embankment material parameters. However, this monitoring is generally insufficient to ensure an adequate safety level against floods. For these reasons there is an increasing demand for fast and accurate investigation methods, such as geophysical techniques. These techniques can provide detailed information on the subsurface structures, are non-invasive, cost-effective, and faster than traditional methods. However, they need verification in order to provide reliable results, particularly in complex and reworked man-made structures such as embankments. In this paper we present a case study in which three different geophysical techniques have been applied: electrical resistivity tomography (ERT), frequency domain electromagnetic induction (FDEM) and Ground Penetrating Radar (GPR). Two test sites have been selected, both located in the Province of Venice (NE Italy) where the Tagliamento River has large embankments. The results obtained with these techniques have been calibrated against evidence resolving from geotechnical investigations. The pros and cons of each technique, as well as their relative merit at identifying the specific features of the embankments in this area, are highlighted. The results demonstrate that geophysical techniques can provide very valuable information for embankment characterization, provided that the data interpretation is constrained via direct evidence, albeit limited in space.

  6. A preliminary evaluation of certain NDA techniques for RH-TRU characterization

    SciTech Connect

    Hartwell, J.K.; Yoon, W.Y.; Peterson, H.K.

    1996-12-31

    This report presents the results of modeling efforts to evaluate selected NDA assay methods for RH-TRU waste characterization. The target waste stream was Content Code 104/107 113-liter waste drums that comprise the majority of the INEL`s RH-TRU waste inventory. Two NDA techniques are treated in detail. One primary NDA technique examined is gamma-ray spectrometry to determine the drum fission and activation product content, and fuel sample inventory calculations using the ORIGEN code to predict the total drum inventory. A heavily shielded and strongly collimated HPGE spectrometer system was designed using MCNP modeling. Detection limits and expected precision of this approach were estimated by a combination of Monte Carlo modeling and synthetic gamma-ray spectrum generation. This technique may allow the radionuclide content of these wastes to be determined with relative standard deviations of 20 to 55% depending on the drum matrix and radionuclide. The INEL Passive/Active Neutron (PAN) assay system is the second primary technique considered. A shielded overpack for the 113-liter CC104/107 RH-TRU drums was designed to shield the PAN detectors from excessive gamma radiation. MCNP modeling suggests PAN detection limits of about 0.06 g {sup 235}U and 0.04 g {sup 239}Pu during active assays.

  7. Whole body MRI: Improved Lesion Detection and Characterization With Diffusion Weighted Techniques

    PubMed Central

    Attariwala, Rajpaul; Picker, Wayne

    2013-01-01

    Diffusion-weighted imaging (DWI) is an established functional imaging technique that interrogates the delicate balance of water movement at the cellular level. Technological advances enable this technique to be applied to whole-body MRI. Theory, b-value selection, common artifacts and target to background for optimized viewing will be reviewed for applications in the neck, chest, abdomen, and pelvis. Whole-body imaging with DWI allows novel applications of MRI to aid in evaluation of conditions such as multiple myeloma, lymphoma, and skeletal metastases, while the quantitative nature of this technique permits evaluation of response to therapy. Persisting signal at high b-values from restricted hypercellular tissue and viscous fluid also permits applications of DWI beyond oncologic imaging. DWI, when used in conjunction with routine imaging, can assist in detecting hemorrhagic degradation products, infection/abscess, and inflammation in colitis, while aiding with discrimination of free fluid and empyema, while limiting the need for intravenous contrast. DWI in conjunction with routine anatomic images provides a platform to improve lesion detection and characterization with findings rivaling other combined anatomic and functional imaging techniques, with the added benefit of no ionizing radiation. PMID:23960006

  8. A preliminary evaluation of certain NDA techniques for RH-TRU characterization

    SciTech Connect

    Hartwell, J.K.; Yoon, W.Y.; Peterson, H.K.

    1997-11-01

    This report presents the results of modeling efforts to evaluate selected NDA assay methods for RH-TRU waste characterization. The target waste stream was Content Code 104/107 113-liter waste drums that comprise the majority of the INEL`s RH-TRU waste inventory. Two NDA techniques are treated in detail. One primary NDA technique examined is gamma-ray spectrometry to determine the drum fission and activation product content, and fuel sample inventory calculations using the ORIGEN code to predict the total drum inventory. A heavily shielded and strongly collimated HPGe spectrometer system was designed using MCNP modeling. Detection limits and expected precision of this approach were estimated by a combination of Monte Carlo modeling and synthetic gamma-ray spectrum generation. This technique may allow the radionuclide content of these wastes to be determined with relative standard deviations of 20 to 50% depending on the drum matrix and radionuclide. The INEL Passive/Active Neutron (PAN) assay system is the second primary technique considered. A shielded overpack for the 113-liter CC104/107 RH-TRU drums was designed to shield the PAN detectors from excessive gamma radiation. MCNP modeling suggests PAN detection limits of about 0.06 g {sup 235}U and 0.04 g {sup 239}Pu during active assays. 12 refs., 2 figs., 6 tabs.

  9. RBS: an analytical technique for elemental characterization of standards; advantages and limits of application

    NASA Astrophysics Data System (ADS)

    Climent-Font, A.; Fernández-Jiménez, M. T.; Wätjen, U.; Perrière, J.

    1994-12-01

    Rutherford backscattering spectrometry (RBS) is an ion beam analytical technique fulfilling unique conditions to give information on the elemental composition of the near surface of materials. Some of the physical processes involved in an RBS experiment are very well understood and are described by analytical formulas allowing for the elaboration of simple computer codes recreating theoretical RBS experiments. Such computer codes are of great help for fast and accurate interpretation of experimental RBS spectra. Under favorable circumstances quantitative composition depth profiles can be obtained. The possibility of doing absolute measurements with RBS makes it very attractive for the characterization of standard samples useful and necessary in other analytical techniques if quantitative analysis is required. In spite of its capabilities, RBS is not free from some flaws that make difficult to reduce the level of uncertainties below 5% in the quantification of the spectra or to make an unambiguous interpretation of the results. In this work we illustrate with a few examples some of the relevant features of RBS which make this analytical technique so useful, and we also discuss situations in which RBS can give only ambiguous information, and where the assistance of a complementary analytical technique is required for a successful interpretation of the results.

  10. Development, implementation, and characterization of a standalone embedded viscosity measurement system based on the impedance spectroscopy of a vibrating wire sensor

    NASA Astrophysics Data System (ADS)

    Santos, José; Janeiro, Fernando M.; Ramos, Pedro M.

    2015-10-01

    This paper presents an embedded liquid viscosity measurement system based on a vibrating wire sensor. Although multiple viscometers based on different working principles are commercially available, there is still a market demand for a dedicated measurement system capable of performing accurate, fast measurements and requiring little or no operator training for simple systems and solution monitoring. The developed embedded system is based on a vibrating wire sensor that works by measuring the impedance response of the sensor, which depends on the viscosity and density of the liquid in which the sensor is immersed. The core of the embedded system is a digital signal processor (DSP) which controls the waveform generation and acquisitions for the measurement of the impedance frequency response. The DSP also processes the acquired waveforms and estimates the liquid viscosity. The user can interact with the measurement system through a keypad and an LCD or through a computer with a USB connection for data logging and processing. The presented system is tested on a set of viscosity standards and the estimated values are compared with the standard manufacturer specified viscosity values. A stability study of the measurement system is also performed.

  11. RF characterization of monolithic microwave and mm-wave ICs

    NASA Technical Reports Server (NTRS)

    Romanofsky, R. R.; Ponchak, G. E.; Shalkhauser, K. A.; Bhasin, K. B.

    1986-01-01

    A number of fixturing techniques compatible with automatic network analysis are presented. The fixtures are capable of characterizing GaAs Monolithic Microwave Integrated Circuits (MMICs) at K and Ka band. Several different transitions are used to couple the RF test port to microstrip. Fixtures which provide chip level de-embedding are included. In addition, two advanced characterization techniques are assessed.

  12. Use of non-standardised micro-destructive techniques in the characterization of traditional construction materials

    NASA Astrophysics Data System (ADS)

    Ioannou, Ioannis; Theodoridou, Magdalini; Modestou, Sevasti; Fournari, Revecca; Dagrain, Fabrice

    2013-04-01

    The characterization of material properties and the diagnosis of their state of weathering and conservation are three of the most important steps in the field of cultural heritage preservation. Several standardised experimental methods exist, especially for determining the material properties and their durability. However, they are limited in their application by the required size of test specimens and the controlled laboratory conditions needed to undertake the tests; this is especially true when the materials under study constitute immovable parts of heritage structures. The current use of other advanced methods of analysis, such as imaging techniques, in the aforementioned field of research offers invaluable results. However, these techniques may not always be accessible to the wider research community due to their complex nature and relatively high cost of application. This study presents innovative applications of two recently developed cutting techniques; the portable Drilling Resistance Measuring System (DRMS) and the scratch tool. Both methods are defined as micro-destructive, since they only destroy a very small portion of sample material. The general concept of both methods lies within the forces needed to cut a material by linear (scratch tool) or rotational (DRMS) cutting action; these forces are related to the mechanical properties of the material and the technological parameters applied on the tool. Therefore, for a given testing configuration, the only parameter influencing the forces applied is the strength of the material. These two techniques have been used alongside a series of standardised laboratory tests aiming at the correlation of various stone properties (density, porosity, dynamic elastic modulus and uniaxial compressive strength). The results prove the potential of both techniques in assessing the uniaxial compressive strength of stones. The scratch tool has also been used effectively to estimate the compressive strength of mud bricks. It

  13. Visual embedding: a model for visualization.

    PubMed

    Demiralp, Çağatay; Scheidegger, Carlos E; Kindlmann, Gordon L; Laidlaw, David H; Heer, Jeffrey

    2014-01-01

    The authors propose visual embedding as a model for automatically generating and evaluating visualizations. A visual embedding is a function from data points to a space of visual primitives that measurably preserves structures in the data (domain) within the mapped perceptual space (range). The authors demonstrate its use with three examples: coloring of neural tracts, scatterplots with icons, and evaluation of alternative diffusion tensor glyphs. They discuss several techniques for generating visual-embedding functions, including probabilistic graphical models for embedding in discrete visual spaces. They also describe two complementary approaches--crowdsourcing and visual product spaces--for building visual spaces with associated perceptual--distance measures. In addition, they recommend several research directions for further developing the visual-embedding model. PMID:24808163

  14. Characterization of radiochromic film scanning techniques used in short-pulse-laser ion acceleration

    SciTech Connect

    Cowan, Joseph S.; Flippo, Kirk A.; Gaillard, Sandrine A.

    2008-10-15

    Radiochromic film (RCF) is increasingly being used as a detector for proton beams from short-pulse laser-matter interaction experiments using the RCF imaging spectroscope technique. The community has traditionally used inexpensive flatbed scanners to digitize and analyze the data, as opposed to more expensive and time-consuming microdensitometers (MicroDs). Often, the RCF densities in some regions exceed an optical density (OD) of 3. Flatbed scanners are generally limited to a maximum OD of {approx}3. Because of the high exposure density, flatbed scanners may yield data that are not reliable due to light scatter and light diffusion from areas of low density to areas of high density. This happens even when the OD is slightly above 1. We will demonstrate the limitations of using flatbed scanners for this type of radiographic media and characterize them compared to measurements made using a MicroD. A technique for cross characterizing both systems using a diffuse densitometer with a NIST wedge will also be presented.

  15. Technique for needle-free drop deposition: Pathway for precise characterization of superhydrophobic surfaces

    NASA Astrophysics Data System (ADS)

    Waghmare, Prashant R.; Das, Siddhartha; Mitra, Sushanta K.

    2013-11-01

    The most important step for characterizing the wettability of a surface is to deposit a water drop on the surface and measure the contact angle made by the drop on the surface. This innocuously simple process relies on bringing a needle holding the water drop in close proximity to the surface, with a ``desire'' that the drop would spontaneously detach from the needle and get deposited on the surface. Problem occurs when the surface is superhydrophobic, expressing an ``unwillingness'' to ``see'' the water drop in preference to a much more ``water-loving'' needle surface. There exists no solution to this problem, and surfaces are invariably characterized where the drop-needle assembly contacts the superhydrophobic surface. Such a configuration will always lead to an incorrect estimation of the contact angle, as there is no certainty of the existence of the drop-surface contact. Here we shall discuss our recently invented technique, where we solve this long-standing problem-we indeed ensure a needle-free drop in contact with the superhydrophobic surface, thereby ascertaining precise determination of the contact angle. The successful application of the technique will address a major headache of the big research community interested in science and technology of superhydrophobic surfaces.

  16. DEVELOPMENT OF RESERVOIR CHARACTERIZATION TECHNIQUES AND PRODUCTION MODELS FOR EXPLOITING NATURALLY FRACTURED RESERVOIRS

    SciTech Connect

    Michael L. Wiggins; Raymon L. Brown; Faruk Civan; Richard G. Hughes

    2002-12-31

    For many years, geoscientists and engineers have undertaken research to characterize naturally fractured reservoirs. Geoscientists have focused on understanding the process of fracturing and the subsequent measurement and description of fracture characteristics. Engineers have concentrated on the fluid flow behavior in the fracture-porous media system and the development of models to predict the hydrocarbon production from these complex systems. This research attempts to integrate these two complementary views to develop a quantitative reservoir characterization methodology and flow performance model for naturally fractured reservoirs. The research has focused on estimating naturally fractured reservoir properties from seismic data, predicting fracture characteristics from well logs, and developing a naturally fractured reservoir simulator. It is important to develop techniques that can be applied to estimate the important parameters in predicting the performance of naturally fractured reservoirs. This project proposes a method to relate seismic properties to the elastic compliance and permeability of the reservoir based upon a sugar cube model. In addition, methods are presented to use conventional well logs to estimate localized fracture information for reservoir characterization purposes. The ability to estimate fracture information from conventional well logs is very important in older wells where data are often limited. Finally, a desktop naturally fractured reservoir simulator has been developed for the purpose of predicting the performance of these complex reservoirs. The simulator incorporates vertical and horizontal wellbore models, methods to handle matrix to fracture fluid transfer, and fracture permeability tensors. This research project has developed methods to characterize and study the performance of naturally fractured reservoirs that integrate geoscience and engineering data. This is an important step in developing exploitation strategies for

  17. Dosimetric characterization and optimization of a customized Stanford total skin electron irradiation (TSEI) technique.

    PubMed

    Luĉić, Felipe; Sánchez-Nieto, Beatriz; Caprile, Paola; Zelada, Gabriel; Goset, Karen

    2013-01-01

    Total skin electron irradiation (TSEI) has been used as a treatment for mycosis fungoides. Our center has implemented a modified Stanford technique with six pairs of 6 MeV adjacent electron beams, incident perpendicularly on the patient who remains lying on a translational platform, at 200 cm from the source. The purpose of this study is to perform a dosimetric characterization of this technique and to investigate its optimization in terms of energy characteristics, extension, and uniformity of the treatment field. In order to improve the homogeneity of the distribution, a custom-made polyester filter of variable thickness and a uniform PMMA degrader plate were used. It was found that the characteristics of a 9 MeV beam with an 8 mm thick degrader were similar to those of the 6 MeV beam without filter, but with an increased surface dose. The combination of the degrader and the polyester filter improved the uniformity of the distribution along the dual field (180cm long), increasing the dose at the borders of field by 43%. The optimum angles for the pair of beams were ± 27°. This configuration avoided displacement of the patient, and reduced the treatment time and the positioning problems related to the abutting superior and inferior fields. Dose distributions in the transversal plane were measured for the six incidences of the Stanford technique with film dosimetry in an anthropomorphic pelvic phantom. This was performed for the optimized treatment and compared with the previously implemented technique. The comparison showed an increased superficial dose and improved uniformity of the 85% isodose curve coverage for the optimized technique. PMID:24036877

  18. Elemental characterization of LL-MA radioactive waste packages with the associated particle technique

    SciTech Connect

    Perot, B.; Carasco, C.; Toure, M.; El Kanawati, W.; Eleon, C.

    2011-07-01

    The French Alternative Energies and Atomic Energy Commission (CEA) and National Radioactive Waste Management Agency (ANDRA) are conducting an R and D program to improve the characterization of long-lived and medium activity (LL-MA) radioactive waste packages with analytical methods and with non-destructive nuclear measurements. This paper concerns fast neutron interrogation with the associated particle technique (APT), which brings 3D information about the waste material composition. The characterization of volume elements filled with iron, water, aluminium, and PVC in bituminized and fibre concrete LL-MA waste packages has been investigated with MCNP [1] and MODAR data analysis software [2]. APT provides usable information about major elements presents in the volumes of interest. However, neutron scattering on hydrogen nuclei spreads the tagged neutron beam out of the targeted volume towards surrounding materials, reducing spatial selectivity. Simulation shows that small less than 1 L targets can be characterised up to the half-radius of a 225 L bituminized drum, the matrix of which is very rich in hydrogen. Deeper characterization in concrete is possible but limited by counting statistics due to photon attenuation in this dense matrix and, unless large inspection volumes are considered, by the lack of spatial selectivity of the tagged neutron beam due to neutron scattering. (authors)

  19. A multi-technique chemical characterization of a Stradivari decorated violin top plate

    NASA Astrophysics Data System (ADS)

    Malagodi, M.; Canevari, C.; Bonizzoni, L.; Galli, A.; Maspero, F.; Martini, M.

    2013-08-01

    This paper focuses on the characterization of the materials of a violin top plate made by Antonio Stradivari (17th century), with different diagnostic techniques and with an integrated and non-destructive analytical methodology to study surface coatings and decorations. The UV-induced visible fluorescence, optical digital microscopy, ED-XRF associated with micro-FTIR spectroscopy analysis, and dendrochronology were performed. The investigations were aimed to identify the presence of original varnish layers and to characterize the composition of the decorations, either the inlaid purflings or the composite false-inlay strip between them. Several results were achieved: (i) evidence of the absence of varnish layers on the surface as a result of extended and inappropriate restoring; (ii) identification of the dye used for the black layers of the purflings; (iii) characterization of the black matrix and the white elements of the decoration. Furthermore, a dendrochronological dating was performed. A copy of the top plate was realized with materials similar to those identified on the Stradivari original; the same analyses performed on the original model were carried out on the same areas of the copy.

  20. Technique for GEO RSO Station-Keeping Characterization and Maneuver Detection

    NASA Astrophysics Data System (ADS)

    Decoto, J.; Loerch, P.

    As the Geosynchronous satellite population increases so too does the importance of accurate catalog maintenance for purpose of conjunction assessment and spacecraft operator situational awareness, particularly for operators in closely spaced regions or in collocated GEO slots. This paper presents the design, results, and limitations of an algorithm developed to aid these efforts by characterizing maneuver histories of geosynchronous satellites using published satellite TLE histories. Central to the algorithm is use of basic signal processing techniques to enhance the ability to detect small orbit changes amongst the noise in the raw data. After filtering out any single point inconsistent outliers the algorithm processes each orbit state with a temporal lead trail window of surrounding orbit states being propagated over a range of common epochs with key metrics being recorded. Potential maneuver events are then declared at any epoch where the comparison metrics between orbit states exceed several checks. Maneuver events are characterized as In-Plane or Out-of-Plane events, referring to the direction of the imparted change in velocity relative to the orbital plane of the satellite. Also characterized is the operational tempo of maneuvers including whether electric or chemical propulsion methods are being used. To illustrate this approach several examples from publicly available catalogs are processed with results provided.

  1. Isolation and characterization of related substances in alogliptin benzoate by LC-QTOF mass spectrometric techniques.

    PubMed

    Lu, Yuting; Yang, Danyi; Li, Zhiyu; Hang, Taijun; Song, Min

    2016-09-01

    A highly specific and efficient LC-QTOF mass spectrometric method was developed for the separation and characterization of process related substances and the major degradation products in alogliptin benzoate and its tablets. The separation was performed on Phenomenex Gemini-NX C18 column (250mm×4.6mm, 5μm) using 0.2% formic acid-0.2% ammonium acetate in water as mobile phase A, acetonitrile and methanol (60:40, v/v) as mobile phase B in linear gradient elution mode. Forced degradation studies were also conducted under ICH prescribed stress conditions. Alogliptin benzoate and its tablets were tending to degrade under acid, alkaline, oxidative and thermal stresses, while relatively stable to photolytic stress. A total of seven related substances were detected and characterized through liquid chromatography-high resolution QTOF mass spectrometry techniques, including process related substances and degradation products, and two of them were further synthesized and characterized by NMR spectroscopy. Based on the related substances elucidation and the plausible formation mechanisms, efficient approaches were proposed to reduce or eliminate related substances, and in consequence the quality of alogliptin benzoate and its tablets have been promoted obviously. Therefore, the impurity profiles obtained are critical to the quality control and manufacturing processes optimization and monitoring of alogliptin benzoate and its tablets. PMID:27281581

  2. Analytical techniques for characterization of cyclodextrin complexes in aqueous solution: a review.

    PubMed

    Mura, Paola

    2014-12-01

    Cyclodextrins are cyclic oligosaccharides endowed with a hydrophilic outer surface and a hydrophobic inner cavity, able to form inclusion complexes with a wide variety of guest molecules, positively affecting their physicochemical properties. In particular, in the pharmaceutical field, cyclodextrin complexation is mainly used to increase the aqueous solubility and dissolution rate of poorly soluble drugs, and to enhance their bioavailability and stability. Analytical characterization of host-guest interactions is of fundamental importance for fully exploiting the potential benefits of complexation, helping in selection of the most appropriate cyclodextrin. The assessment of the actual formation of a drug-cyclodextrin inclusion complex and its full characterization is not a simple task and often requires the use of different analytical methods, whose results have to be combined and examined together. The purpose of the present review is to give, as much as possible, a general overview of the main analytical tools which can be employed for the characterization of drug-cyclodextrin inclusion complexes in solution, with emphasis on their respective potential merits, disadvantages and limits. Further, the applicability of each examined technique is illustrated and discussed by specific examples from literature. PMID:24680374

  3. Characterization of the microbial acid mine drainage microbial community using culturing and direct sequencing techniques.

    PubMed

    Auld, Ryan R; Myre, Maxine; Mykytczuk, Nadia C S; Leduc, Leo G; Merritt, Thomas J S

    2013-05-01

    We characterized the bacterial community from an AMD tailings pond using both classical culturing and modern direct sequencing techniques and compared the two methods. Acid mine drainage (AMD) is produced by the environmental and microbial oxidation of minerals dissolved from mining waste. Surprisingly, we know little about the microbial communities associated with AMD, despite the fundamental ecological roles of these organisms and large-scale economic impact of these waste sites. AMD microbial communities have classically been characterized by laboratory culturing-based techniques and more recently by direct sequencing of marker gene sequences, primarily the 16S rRNA gene. In our comparison of the techniques, we find that their results are complementary, overall indicating very similar community structure with similar dominant species, but with each method identifying some species that were missed by the other. We were able to culture the majority of species that our direct sequencing results indicated were present, primarily species within the Acidithiobacillus and Acidiphilium genera, although estimates of relative species abundance were only obtained from direct sequencing. Interestingly, our culture-based methods recovered four species that had been overlooked from our sequencing results because of the rarity of the marker gene sequences, likely members of the rare biosphere. Further, direct sequencing indicated that a single genus, completely missed in our culture-based study, Legionella, was a dominant member of the microbial community. Our results suggest that while either method does a reasonable job of identifying the dominant members of the AMD microbial community, together the methods combine to give a more complete picture of the true diversity of this environment. PMID:23485423

  4. The Role of Lattice Matching Techniques in the Characterization of Polymorphic Forms

    PubMed Central

    Mighell, Alan D.

    2011-01-01

    An inspection of the recent literature reveals that polymorphism is a frequently encountered phenomenon. The recognition of polymorphic forms plays a vital role in the materials sciences because such structures are characterized by different crystal packing and accordingly have different physical properties. In the pharmaceutical industry, recognition of polymorphic forms can be critical for, in certain cases, a polymorphic form of a drug may be an ineffective therapeutic agent due to its unfavorable physical properties. A check of the recent literature has revealed that in some cases new polymorphic forms are not recognized. In other instances, a supposedly new polymeric form is actually the result of an incorrect structure determination. Fortunately, lattice-matching techniques, which have proved invaluable in the identification and characterization of crystal structures, represent a powerful tool for analyzing polymorphic forms. These lattice-matching methods are based on either of two strategies: (a) the reduced cell strategy–the matching of reduced cells of the respective lattices or (b) the matrix strategy–the determination of a matrix or matrices relating the two lattices coupled with an analysis of the matrix elements. Herein, these techniques are applied to three typical cases–(a) the identification of a new polymorphic form, (b) the demonstration that a substance may not be a new polymorphic form due to missed symmetry, and (c) the evaluation of pseudo polymorphism because of a missed lattice. To identify new polymorphic forms and to prevent errors, it is recommended that these lattice matching techniques become an integral part of the editorial review process of crystallography journals. PMID:26989586

  5. A surface-based technique for mapping homotopic interhemispheric connectivity: Development, characterization, and clinical application.

    PubMed

    Tobyne, Sean M; Boratyn, Daria; Johnson, Jessica A; Greve, Douglas N; Mainero, Caterina; Klawiter, Eric C

    2016-08-01

    The functional organization of the human brain consists of a high degree of connectivity between interhemispheric homologous regions. The degree of homotopic organization is known to vary across the cortex and homotopic connectivity is high in regions that share cross-hemisphere structural connections or are activated by common input streams (e.g., the visual system). Damage to one or both regions, as well as damage to the connections between homotopic regions, could disrupt this functional organization. Here were introduce and test a computationally efficient technique, surface-based homotopic interhermispheric connectivity (sHIC), that leverages surface-based registration and processing techniques in an attempt to improve the spatial specificity and accuracy of cortical interhemispheric connectivity estimated with resting state functional connectivity. This technique is shown to be reliable both within and across subjects. sHIC is also characterized in a dataset of nearly 1000 subjects. We confirm previous results showing increased interhemispheric connectivity in primary sensory regions, and reveal a novel rostro-caudal functionally defined network level pattern of sHIC across the brain. In addition, we demonstrate a structural-functional relationship between sHIC and atrophy of the corpus callosum in multiple sclerosis (r = 0.2979, p = 0.0461). sHIC presents as a sensitive and reliable measure of cortical homotopy that may prove useful as a biomarker in neurologic disease. Hum Brain Mapp 37:2849-2868, 2016. © 2016 Wiley Periodicals, Inc. PMID:27219660

  6. Thermal characterization of a liquid resin for 3D printing using photothermal techniques

    NASA Astrophysics Data System (ADS)

    Jiménez-Pérez, José L.; Pincel, Pavel Vieyra; Cruz-Orea, Alfredo; Correa-Pacheco, Zormy N.

    2016-05-01

    Thermal properties of a liquid resin were studied by thermal lens spectrometry (TLS) and open photoacoustic cell (OPC), respectively. In the case of the TLS technique, the two mismatched mode experimental configuration was used with a He-Ne laser, as a probe beam and an Argon laser was used as the excitation source. The characteristic time constant of the transient thermal lens was obtained by fitting the theoretical expression to the experimental data in order to obtain the thermal diffusivity ( α) of the resin. On the other hand, the sample thermal effusivity ( e) was obtained by using the OPC technique. In this technique, an Argon laser was used as the excitation source and was operated at 514 nm with an output power of 30 mW. From the obtained thermal diffusivity ( α) and thermal effusivity ( e) values, the thermal conductivity ( k) and specific heat capacity per unit volume ( ρc) of resin were calculated through the relationships k = e( α)1/2 and ρc = e/( α)1/2. The obtained thermal parameters were compared with the thermal parameters of the literature. To our knowledge, the thermal characterization of resin has not been reported until now. The present study has applications in laser stereo-lithography to manufacture 3D printing pieces.

  7. Analysis and evaluation of interwell seismic logging techniques for hydrocarbon reservoir characterization. Final report

    SciTech Connect

    Parra, J.O.; Zook, B.J.; Sturdivant, V.R.

    1994-06-01

    The work reported herein represents the third year work in evaluating high-resolution interwell seismic logging techniques for hydrocarbon reservoir characterization. The objective of this project is to investigate interwell seismic logging techniques for indirectly interpreting oil and gas reservoir geology and rock physical properties. The work involves a balanced study of theoretical and numerical modeling of seismic waves transmitted between pairs of wells combined with experimental data acquisition and processing at controlled field conditions. The field applications of this reservoir probing concept are aimed at demonstrating high resolution measurements and detailed interpretation of heterogeneous hydrocarbon-bearing formations. The first part of this third year project efforts was devoted to thoroughly evaluating interwell seismic logging and reverse VSP in a hydrocarbon-bearing formation at the Buckhorn test site in Illinois. Specifically, the data from the experiments conducted in the second year of this project were analyzed to delineate geological structures and to extract rock physical parameters. The second part of this project is devoted to the evaluation of continuity logging techniques for hydrocarbon reservoir continuity. Specifically, this part of the project includes the evaluation of methods of measurements, modeling and data processing to delineate the reservoir architecture and relate dispersion and attenuation measurements to rock physical properties.

  8. Optical fiber sensors embedded in flexible polymer foils

    NASA Astrophysics Data System (ADS)

    van Hoe, Bram; van Steenberge, Geert; Bosman, Erwin; Missinne, Jeroen; Geernaert, Thomas; Berghmans, Francis; Webb, David; van Daele, Peter

    2010-04-01

    In traditional electrical sensing applications, multiplexing and interconnecting the different sensing elements is a major challenge. Recently, many optical alternatives have been investigated including optical fiber sensors of which the sensing elements consist of fiber Bragg gratings. Different sensing points can be integrated in one optical fiber solving the interconnection problem and avoiding any electromagnetical interference (EMI). Many new sensing applications also require flexible or stretchable sensing foils which can be attached to or wrapped around irregularly shaped objects such as robot fingers and car bumpers or which can even be applied in biomedical applications where a sensor is fixed on a human body. The use of these optical sensors however always implies the use of a light-source, detectors and electronic circuitry to be coupled and integrated with these sensors. The coupling of these fibers with these light sources and detectors is a critical packaging problem and as it is well-known the costs for packaging, especially with optoelectronic components and fiber alignment issues are huge. The end goal of this embedded sensor is to create a flexible optical sensor integrated with (opto)electronic modules and control circuitry. To obtain this flexibility, one can embed the optical sensors and the driving optoelectronics in a stretchable polymer host material. In this article different embedding techniques for optical fiber sensors are described and characterized. Initial tests based on standard manufacturing processes such as molding and laser structuring are reported as well as a more advanced embedding technique based on soft lithography processing.

  9. Dimension of spatially embedded networks

    NASA Astrophysics Data System (ADS)

    Daqing, Li; Kosmidis, Kosmas; Bunde, Armin; Havlin, Shlomo

    2011-06-01

    The dimension of a system is one of the most fundamental quantities to characterize its structure and basic physical properties. Diffusion and vibrational excitations, for example, as well as the universal features of a system near a critical point depend crucially on its dimension. However, in the theory of complex networks the concept of dimension has been rarely discussed. Here we study models for spatially embedded networks and show how their dimension can be determined. Our results indicate that networks characterized by a broad distribution of link lengths have a dimension higher than that of the embedding space. We illustrate our findings using the global airline network and the Internet and argue that although these networks are embedded in two-dimensional space they should be regarded as systems with dimension close to 3 and 4.5, respectively. We show that the network dimension is a key concept to understand not only network topology, but also dynamical processes on networks, such as diffusion and critical phenomena including percolation.

  10. The data embedding method

    SciTech Connect

    Sandford, M.T. II; Bradley, J.N.; Handel, T.G.

    1996-06-01

    Data embedding is a new steganographic method for combining digital information sets. This paper describes the data embedding method and gives examples of its application using software written in the C-programming language. Sandford and Handel produced a computer program (BMPEMBED, Ver. 1.51 written for IBM PC/AT or compatible, MS/DOS Ver. 3.3 or later) that implements data embedding in an application for digital imagery. Information is embedded into, and extracted from, Truecolor or color-pallet images in Microsoft{reg_sign} bitmap (.BMP) format. Hiding data in the noise component of a host, by means of an algorithm that modifies or replaces the noise bits, is termed {open_quote}steganography.{close_quote} Data embedding differs markedly from conventional steganography, because it uses the noise component of the host to insert information with few or no modifications to the host data values or their statistical properties. Consequently, the entropy of the host data is affected little by using data embedding to add information. The data embedding method applies to host data compressed with transform, or {open_quote}lossy{close_quote} compression algorithms, as for example ones based on discrete cosine transform and wavelet functions. Analysis of the host noise generates a key required for embedding and extracting the auxiliary data from the combined data. The key is stored easily in the combined data. Images without the key cannot be processed to extract the embedded information. To provide security for the embedded data, one can remove the key from the combined data and manage it separately. The image key can be encrypted and stored in the combined data or transmitted separately as a ciphertext much smaller in size than the embedded data. The key size is typically ten to one-hundred bytes, and it is in data an analysis algorithm.

  11. Efficient high-capacity steganography technique

    NASA Astrophysics Data System (ADS)

    Abdulla, Alan A.; Jassim, Sabah A.; Sellahewa, Harin

    2013-05-01

    Performance indicators characterizing modern steganographic techniques include capacity (i.e. the quantity of data that can be hidden in the cover medium), stego quality (i.e. artifacts visibility), security (i.e. undetectability), and strength or robustness (intended as the resistance against active attacks aimed to destroy the secret message). Fibonacci based embedding techniques have been researched and proposed in the literature to achieve efficient steganography in terms of capacity with respect to stego quality. In this paper, we investigated an innovative idea that extends Fibonacci-like steganography by bit-plane(s) mapping instead of bit-plane(s) replacement. Our proposed algorithm increases embedding capacity using bit-plane mapping to embed two bits of the secret message in three bits of a pixel of the cover, at the expense of a marginal loss in stego quality. While existing Fibonacci embedding algorithms do not use certain intensities of the cover for embedding due to the limitation imposed by the Zeckendorf theorem, our proposal solve this problem and make all intensity values candidates for embedding. Experimental results demonstrate that the proposed technique double the embedding capacity when compared to existing Fibonacci methods, and it is secure against statistical attacks such as RS, POV, and difference image histogram (DIH).

  12. Study to perform preliminary experiments to evaluate particle generation and characterization techniques for zero-gravity cloud physics experiments

    NASA Technical Reports Server (NTRS)

    Katz, U.

    1982-01-01

    Methods of particle generation and characterization with regard to their applicability for experiments requiring cloud condensation nuclei (CCN) of specified properties were investigated. Since aerosol characterization is a prerequisite to assessing performance of particle generation equipment, techniques for characterizing aerosol were evaluated. Aerosol generation is discussed, and atomizer and photolytic generators including preparation of hydrosols (used with atomizers) and the evaluation of a flight version of an atomizer are studied.

  13. Joint application of non-invasive techniques to characterize the dynamic behaviuor of engineering structures

    NASA Astrophysics Data System (ADS)

    Gallipoli, M. R.; Perrone, A.; Stabile, T. A.; Ponzo, F. C.; Ditommaso, R.

    2012-04-01

    The systematic monitoring of strategic civil infrastructures such as bridges, large dams or high-rise buildings in order to ensure their structural stability is a strategic issue particularly in earthquake-prone regions. Nevertheless, in areas less exposed to seismic hazard, the monitoring is also an important tool for civil engineers, for instance if they have to deal with structures exposed to heavy operational demands for extended periods of time and whose structural integrity might be in question or at risk. A continuous monitoring of such structures allows the identification of their fundamental response characteristics and the changes of these over time, the latter representing indicators for potential structural degradation. The aim of this paper is the estimation of fundamental dynamic parameters of some civil infrastructures by the joint application of fast executable, non-invasive techniques such as the Ambient Noise Standard Spectral Ratio, and Ground-Based microwave Radar Interferometer techniques. The joint approach combine conventional, non-conventional and innovative techniques in order to set up a non destructive evaluation procedure allowing for a multi-sensing monitoring at a multi-scale and multi-depth levels (i.e. with different degrees of spatial resolution and different subsurface depths). In particular, techniques based on ambient vibration recordings have become a popular tool for characterizing the seismic response and state-of-health of strategic civil infrastructure. The primary advantage of these approaches lies in the fact that no transient earthquake signals or even active excitation of the structure under investigation are required. The microwave interferometry radar technology, it has proven to be a powerful remote sensing tool for vibration measurement of structures, such as bridge, heritage architectural structures, vibrating stay cables, and engineering structures. The main advantage of this radar technique is the possibility to

  14. Embedded gage impact study

    NASA Technical Reports Server (NTRS)

    Schramm, S. W.; Daniel, I. M.

    1984-01-01

    Impact damage in graphite/epoxy laminates was characterized and transient strain history during impact was correlated. The material investigated was AS-4/3501-6 graphite/epoxy. Eight-ply and sixteen-ply quasi-isotropic laminates of 45/0/-45/90 sub s and 45/0/-45/90 sub 2s layups were fabricated with strain gages embedded between plies during the strain gages and leads from the highly conductive graphite fibers. The specimens were circular plates 12.7 cm (5 in.) in diameter and clamped along their circumference. The specimens were impacted with a 185 gm impactor, dropped from heights of 1.20 m and 1.65 m. An accelerometer was attached to the back surface of the specimen opposite the impact point and was used to trigger the recording instrumentation. The transient strain data were recorded with an eight channel waveform digitizer capable of sampling data at 0.5 microsec intervals. The data were stored, processed, and plotted by means of a microcomputer. Transient strain data were correlated with results from ultrasonic inspection of the specimens.

  15. Nationale Roadmap Embedded Systems

    NASA Astrophysics Data System (ADS)

    Damm, Werner; Achatz, Reinhold; Beetz, Klaus; Broy, Manfred; Daembkes, Heinrich; Grimm, Klaus; Liggesmeyer, Peter

    Eingebettete Systeme" sind in ihrem Softwareanteil nicht sichtbar und doch hoch relevant für den Wirtschaftsstandort Deutschland. Ihre Bedeutung fasst die vorliegende Nationale Roadmap Embedded Systems in den folgenden 10 Thesen zusammen: These 1 Die zentralen ökonomischen und gesellschaftlichen Herausforderungen in Deutschland lassen sich ohne die Querschnittstechnologie Embedded Systems nicht lösen1.

  16. Nanogels based on alginic aldehyde and gelatin by inverse miniemulsion technique: synthesis and characterization.

    PubMed

    Sarika, P R; Anil Kumar, P R; Raj, Deepa K; James, Nirmala Rachel

    2015-03-30

    Nanogels were developed from alginic aldehyde and gelatin by an inverse miniemulsion technique. Stable inverse miniemulsions were prepared by sonication of noncontinuous aqueous phase (mixture of alginic aldehyde and gelatin) in a continuous organic phase (Span 20 dissolved in cyclohexane). Cross-linking occurred between alginic aldehyde (AA) and gelatin (gel) in the presence of borax by Schiff's base reaction during the formation of inverse miniemulsion. The effects of surfactant (Span 20) concentration, volume of the aqueous phase and AA/gel weight ratio on the size of the alginic aldehyde-gelatin (AA-gel) nanoparticles were studied. Nanogels were characterized by DLS, FT-IR spectroscopy, TGA, SEM and TEM. DLS, TEM and SEM studies demonstrated nanosize and spherical morphology of the nanogels. Hemocompatibility and in vitro cytocompatibility analyses of the nanogels proved their nontoxicity. The results indicated the potential of the present nanogel system as a candidate for drug- and gene-delivery applications. PMID:25563951

  17. In situ characterization of natural pyrite bioleaching using electrochemical noise technique

    NASA Astrophysics Data System (ADS)

    Chen, Guo-bao; Yang, Hong-ying; Li, Hai-jun

    2016-02-01

    An in situ characterization technique called electrochemical noise (ECN) was used to investigate the bioleaching of natural pyrite. ECN experiments were conducted in four active systems (sulfuric acid, ferric-ion, 9k culture medium, and bioleaching solutions). The ECN data were analyzed in both the time and frequency domains. Spectral noise impedance spectra obtained from power spectral density (PSD) plots for different systems were compared. A reaction mechanism was also proposed on the basis of the experimental data analysis. The bioleaching system exhibits the lowest noise resistance of 0.101 MΩ. The bioleaching of natural pyrite is considered to be a bio-battery reaction, which distinguishes it from chemical oxidation reactions in ferric-ion and culture-medium (9k) solutions. The corrosion of pyrite becomes more severe over time after the long-term testing of bioleaching.

  18. Identification and characterization of colorectal cancer using Raman spectroscopy and feature selection techniques.

    PubMed

    Li, Shaoxin; Chen, Gong; Zhang, Yanjiao; Guo, Zhouyi; Liu, Zhiming; Xu, Junfa; Li, Xueqiang; Lin, Lin

    2014-10-20

    This study aims to detect colorectal cancer with near-infrared Raman spectroscopy and feature selection techniques. A total of 306 Raman spectra of colorectal cancer tissues and normal tissues are acquired from 44 colorectal cancer patients. Five diagnostically important Raman bands in the regions of 815-830, 935-945, 1131-1141, 1447-1457 and 1665-1675 cm(-1) related to proteins, nucleic acids and lipids of tissues are identified with the ant colony optimization (ACO) and support vector machine (SVM). The diagnostic models built with the identified Raman bands provide a diagnostic accuracy of 93.2% for identifying colorectal cancer from normal Raman spectroscopy. The study demonstrates that the Raman spectroscopy associated with ACO-SVM diagnostic algorithms has great potential to characterize and diagnose colorectal cancer. PMID:25401621

  19. Characterization of protein N-glycosylation by tandem mass spectrometry using complementary fragmentation techniques

    DOE PAGESBeta

    Ford, Kristina L.; Zeng, Wei; Heazlewood, Joshua L.; Bacic, Antony

    2015-08-28

    The analysis of post-translational modifications (PTMs) by proteomics is regarded as a technically challenging undertaking. While in recent years approaches to examine and quantify protein phosphorylation have greatly improved, the analysis of many protein modifications, such as glycosylation, are still regarded as problematic. Limitations in the standard proteomics workflow, such as use of suboptimal peptide fragmentation methods, can significantly prevent the identification of glycopeptides. The current generation of tandem mass spectrometers has made available a variety of fragmentation options, many of which are becoming standard features on these instruments. Lastly, we have used three common fragmentation techniques, namely CID, HCD,more » and ETD, to analyze a glycopeptide and highlight how an integrated fragmentation approach can be used to identify the modified residue and characterize the N-glycan on a peptide.« less

  20. Characterization of protein N-glycosylation by tandem mass spectrometry using complementary fragmentation techniques

    SciTech Connect

    Ford, Kristina L.; Zeng, Wei; Heazlewood, Joshua L.; Bacic, Antony

    2015-08-28

    The analysis of post-translational modifications (PTMs) by proteomics is regarded as a technically challenging undertaking. While in recent years approaches to examine and quantify protein phosphorylation have greatly improved, the analysis of many protein modifications, such as glycosylation, are still regarded as problematic. Limitations in the standard proteomics workflow, such as use of suboptimal peptide fragmentation methods, can significantly prevent the identification of glycopeptides. The current generation of tandem mass spectrometers has made available a variety of fragmentation options, many of which are becoming standard features on these instruments. Lastly, we have used three common fragmentation techniques, namely CID, HCD, and ETD, to analyze a glycopeptide and highlight how an integrated fragmentation approach can be used to identify the modified residue and characterize the N-glycan on a peptide.

  1. Characterization of a one dimensional focusing compound refractive lens using the rotating shearing interferometer technique

    SciTech Connect

    Wang Hongchang; Berujon, Sebastien; Sawhney, Kawal

    2012-07-31

    A one dimensional (1D) compound refractive lens (CRL) has been characterized using the grating based rotating shearing interferometer technique. The method is based on the calculation of moire fringes orientation to sense wavefront information. The phase shift and the optical aberration introduced by the 1D CRL on an X-ray beam were retrieved from a single moire fringe image. The radius of curvature of the lens at the apex was derived. This physical radius of the CRL, which is also closely related to the focal length of the 1D CRL, was shown to vary with the incident angle of the incoming X-ray beam onto the CRL. The experimental measurement agreed very well with the theoretical expectations.

  2. Impact of advanced microstructural characterization techniques on modeling and analysis of radiation damage

    SciTech Connect

    Garner, F.A.; Odette, G.R.

    1980-01-01

    The evolution of radiation-induced alterations of dimensional and mechanical properties has been shown to be a direct and often predictable consequence of radiation-induced microstructural changes. Recent advances in understanding of the nature and role of each microstructural component in determining the property of interest has led to a reappraisal of the type and priority of data needed for further model development. This paper presents an overview of the types of modeling and analysis activities in progress, the insights that prompted these activities, and specific examples of successful and ongoing efforts. A review is presented of some problem areas that in the authors' opinion are not yet receiving sufficient attention and which may benefit from the application of advanced techniques of microstructural characterization. Guidelines based on experience gained in previous studies are also provided for acquisition of data in a form most applicable to modeling needs.

  3. Self-normalized photoacoustic technique for thermo-optical characterization of samples mounted between transparent media

    NASA Astrophysics Data System (ADS)

    Balderas-López, J. A.; Díaz-Reyes, J.; Jaime-Fonseca, M. R.; Martínez-Pérez, L.; Pescador-Rojas, J. A.

    2016-03-01

    A self-normalized photoacoustic technique for thermo-optical characterization of materials, mounted between transparent media, is presented. It involves a complex ratio of photoacoustic signals in transmission and front configurations, taking the modulation frequency as the only variable. The analytical solutions for the corresponding 1D heat diffusion problems are analyzed to provide suitable methodologies for measuring the optical absorption coefficients and thermal diffusivity of such samples. This methodology was tested by measuring the optical absorption coefficient, at 660 nm, of methylene blue solutions at various concentrations and the thermal diffusivity of a black drawing ink sample. In addition, an approximated range of optical absorption coefficients, where this photoacoustic methodology is adequate, was established.

  4. A study of the stress wave factor technique for the characterization of composite materials

    NASA Technical Reports Server (NTRS)

    Henneke, E. G., II; Duke, J. C., Jr.; Stinchcomb, W. W.; Govada, A.; Lemascon, A.

    1983-01-01

    A testing program was undertaken to provide an independent investigation and evaluation of the stress wave factor for characterizing the mechanical behavior of composite laminates. Some of the data which was obtained after performing a very large number of tests to determine the reproducibility of the SWF measurement is presented. It was determined that, with some optimizing of experimental parameters, the SWF value can be reproduced to within + or - 10%. Results are also given which show that, after careful calibration procedures, the lowest SWF value along the length of a specimen will correlate very closely to the site of final failure when the specimen is loaded in tension. Finally, using a moire interferometry technique, it was found that local regions having the highest in plane strains under tensile loading also had the lowest SWF values.

  5. Forward-Inverse Adaptive Techniques for Reservoir Characterization and Simulation: Theory and Applications

    SciTech Connect

    Doss, S D; Ezzedine, S; Gelinas, R; Chawathe, A

    2001-06-11

    A novel approach called Forward-Inverse Adaptive Techniques (FIAT) for reservoir characterization is developed and applied to three representative exploration cases. Inverse modeling refers to the determination of the entire reservoir permeability under steady state single-phase flow regime, given only field permeability, pressure and production well measurements. FIAT solves the forward and inverse partial differential equations (PDEs) simultaneously by adding a regularization term and filtering pressure gradients. An implicit adaptive-grid, Galerkin, numerical scheme is used to numerically solve the set of PDEs subject to pressure and permeability boundary conditions. Three examples are presented. Results from all three cases demonstrate attainable and reasonably accurate solutions and, more importantly, provide insights into the consequences of data undersampling.

  6. A first look at roadheader construction and estimating techniques for site characterization at Yucca Mountain, Nevada

    SciTech Connect

    Neil, D.M.; Taylor, D.L.

    1991-12-31

    The Yucca Mountain site characterization program will be based on mechanical excavation techniques for the mined repository construction and development. Tunnel Boring Machines (TBM`s), Mobile Miners (MM), Raiseborers (RB), Blind Hole Shaft Boring Machines (BHSB), and Roadheaders (RH) have been selected as the mechanical excavation machines most suited to mine the densely welded and non-welded tuffs of the Topopah Springs and Calico Hills members. Heavy duty RH in the 70 to 100 ton class with 300 Kw cutter motors have been evaluated and formulas developed to predict machine performance based on the rock physical properties and the results of Linear Cutting Machine (LCM) tests done at the Colorado School of Mines (CSM) for Sandia National Labs. (SNL).

  7. Mechanical characterization of TiO{sub 2} nanofibers produced by different electrospinning techniques

    SciTech Connect

    Vahtrus, Mikk; Šutka, Andris; Vlassov, Sergei; Šutka, Anna; Polyakov, Boris; Saar, Rando; Dorogin, Leonid; Lõhmus, Rünno

    2015-02-15

    In this work TiO{sub 2} nanofibers produced by needle and needleless electrospinning processes from the same precursor were characterized and compared using Raman spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and in situ SEM nanomechanical testing. Phase composition, morphology, Young's modulus and bending strength values were found. Weibull statistics was used to evaluate and compare uniformity of mechanical properties of nanofibers produced by two different methods. It is shown that both methods yield nanofibers with very similar properties. - Graphical abstract: Display Omitted - Highlights: • TiO{sub 2} nanofibers were produced by needle and needleless electrospinning processes. • Structure was studied by Raman spectroscopy and electron microscopy methods. • Mechanical properties were measured using advanced in situ SEM cantilevered beam bending technique. • Both methods yield nanofibers with very similar properties.

  8. Characterization of protein N-glycosylation by tandem mass spectrometry using complementary fragmentation techniques

    PubMed Central

    Ford, Kristina L.; Zeng, Wei; Heazlewood, Joshua L.; Bacic, Antony

    2015-01-01

    The analysis of post-translational modifications (PTMs) by proteomics is regarded as a technically challenging undertaking. While in recent years approaches to examine and quantify protein phosphorylation have greatly improved, the analysis of many protein modifications, such as glycosylation, are still regarded as problematic. Limitations in the standard proteomics workflow, such as use of suboptimal peptide fragmentation methods, can significantly prevent the identification of glycopeptides. The current generation of tandem mass spectrometers has made available a variety of fragmentation options, many of which are becoming standard features on these instruments. We have used three common fragmentation techniques, namely CID, HCD, and ETD, to analyze a glycopeptide and highlight how an integrated fragmentation approach can be used to identify the modified residue and characterize the N-glycan on a peptide. PMID:26379696

  9. Diffusion and ideal MRI techniques to characterize limb-girdle muscular dystrophy

    NASA Astrophysics Data System (ADS)

    Hernández-Salazar, G.; Hidalgo-Tobon, S.; Vargas-Cañas, S.; Marrufo-Melendez, O.; Solis-Najera, S.; Taboada-Barajas, J.; Rodríguez, A. O.; Delgado-Hernández, R.

    2012-10-01

    Limb-girdle muscular dystrophies (LGMD) are a group of autosomal dominantly or recessively inherited muscular dystrophies that also present with primary proximal (limb-girdle) muscle weakness. In the thigh, muscles at the back are affected, with a tendency to preserve the tibialis anterior and gastrocnemius. The aim of this study was to compare quantitative MRI measurements from IDEAL-based imaging and DW imaging in the thigh muscles of adults with LGMDs and healthy volunteers(HC). Six women (three patients and three healthy volunteers) were examined. Imaging experiments were conducted on a 1.5T GE scanner (General Electric Medical Systems. Milwaukee). T1 IDEAL 2D images and diffusion images were acquired. Results demonstrated that the use of noninvasive MRI techniques may provide the means to characterize the muscle through quantitative methods to determine the percentage of fat and ADC values.

  10. Characterization of beam dynamics in the APS injector rings using time-resolved imaging techniques

    SciTech Connect

    Yang, B.X.; Lumpkin, A.H.; Borland, M.

    1997-06-01

    Images taken with streak cameras and gated intensified cameras with both time (longitudinal) and spatial (transverse) resolution reveal a wealth of information about circular accelerators. The authors illustrate a novel technique by a sequence of dual-sweep streak camera images taken at a high dispersion location in the booster synchrotron, where the horizontal coordinate is strongly correlated with the particle energy and the {open_quotes}top-view{close_quotes} of the beam gives a good approximation to the particle density distribution in the longitudinal phase space. A sequence of top-view images taken fight after injection clearly shows the beam dynamics in the phase space. We report another example from the positron accumulator ring for the characterization of its beam compression bunching with the 12th harmonic rf.

  11. Optimization of site characterization and remediation methods using 3-D geoscience modeling and visualization techniques

    SciTech Connect

    Hedegaard, R.F.; Ho, J.; Eisert, J.

    1996-12-31

    Three-dimensional (3-D) geoscience volume modeling can be used to improve the efficiency of the environmental investigation and remediation process. At several unsaturated zone spill sites at two Superfund (CERCLA) sites (Military Installations) in California, all aspects of subsurface contamination have been characterized using an integrated computerized approach. With the aide of software such as LYNX GMS{trademark}, Wavefront`s Data Visualizer{trademark} and Gstools (public domain), the authors have created a central platform from which to map a contaminant plume, visualize the same plume three-dimensionally, and calculate volumes of contaminated soil or groundwater above important health risk thresholds. The developed methodology allows rapid data inspection for decisions such that the characterization process and remedial action design are optimized. By using the 3-D geoscience modeling and visualization techniques, the technical staff are able to evaluate the completeness and spatial variability of the data and conduct 3-D geostatistical predictions of contaminant and lithologic distributions. The geometry of each plume is estimated using 3-D variography on raw analyte values and indicator thresholds for the kriged model. Three-dimensional lithologic interpretation is based on either {open_quote}linked{close_quote} parallel cross sections or on kriged grid estimations derived from borehole data coded with permeability indicator thresholds. Investigative borings, as well as soil vapor extraction/injection wells, are sighted and excavation costs are estimated using these results. The principal advantages of the technique are the efficiency and rapidity with which meaningful results are obtained and the enhanced visualization capability which is a desirable medium to communicate with both the technical staff as well as nontechnical audiences.

  12. Application of different molecular techniques for characterization of catalase-positive cocci isolated from sucuk.

    PubMed

    Kesmen, Zülal; Yarimcam, Burcu; Aslan, Hakiye; Ozbekar, Esra; Yetim, Hasan

    2014-02-01

    This study was carried out for the characterization and discrimination of the indigenous Gram positive, catalase-positive cocci (GCC) population in sucuk, a traditional Turkish dry-fermented sausage. Sucuk samples, produced by the traditional method without starter culture were collected from 8 local producers in Kayseri/Turkey and a total of 116 GCC isolates were identified by using different molecular techniques. Two different molecular fingerprinting methods; namely, randomly amplified polymorphic DNA-PCR (RAPD-PCR) and repetitive extragenic palindrome-PCR (rep-PCR), were used for the clustering of isolates and identification at species level was carried out by full length sequencing of 16S rDNA. Combining the results obtained from molecular fingerprinting and 16S rDNA sequencing showed that the dominant GCC species isolated from the sucuk samples was Staphylococcus saprophyticus followed by Staphylococcus succinus and Staphylococcus equorum belonging to the Staphylococcus genus. Real-time PCR DNA melting curve analysis and high-resolution melting (HRM) analysis targeting the V1 + V3 regions of 16S rDNA were also applied for the discrimination of isolates belonging to different species. It was observed statistically different Tm values and species-specific HRM profiles for all except 2 species (S. saprophyticus and Staphylococcus xylosus) that have high 16S rDNA sequence similarity. The combination of rep-PCR and/or PCR-RAPD with 16S rRNA gene sequencing was an efficient approach for the characterization and identification of the GCC population in spontaneously fermented sucuk. On the other hand, intercalating dye assays were found to be a simple and very promising technique for the differentiation of the GCC population at species level. PMID:24410408

  13. Far-infrared embedding impedance measurements

    NASA Technical Reports Server (NTRS)

    Neikirk, D. P.; Rutledge, D. B.

    1984-01-01

    A technique which allows the measurement of detector embedding impedance has been developed. By using a bismuth microbolometer as a variable resistance load the impedance of one element in a bow-tie antenna array operating at 94 GHz was inferred. The technique is frequency insensitive, and could be used throughout the far-infrared.

  14. Characterization of itraconazole semisolid dosage forms prepared by hot melt technique.

    PubMed

    Shim, Sang-Young; Ji, Chang-Won; Sah, Hongkee; Park, Eun-Seok; Lee, Beom-Jin

    2006-11-01

    The objective of this study was to formulate itraconazole semisolid dosage forms and characterize their physicochemical properties. Itraconazole and excipients such as polysorbate 80, fatty acids, fatty alcohols, oils and organic acids were melted at 160 degrees C. The fused solution was then cooled immediately at -10 degrees C to make wax-like semisolid preparations. Their physicochemical attributes were first characterized using differential scanning calorimetry, Fourier transform infrared spectroscopy and nuclear magnetic resonance spectrometry. The solubility of itraconazole in semisolid preparations and their dispersability in the simulated gastric fluid were also determined. Our semisolid preparations did not show any distinct endothermic peak of a crystalline form of itraconazole around 160-163 degrees C. This suggested that it was changed into amorphous one, when it was formulated into semisolid preparations. In addition, the distinctive functional peaks and chemical shifts of itraconazole were well retained after processing into semisolid preparations. It could be inferred from the data that itraconazole was stable during incorporation into semisolid preparations by the hot melt technique. In particular, itraconazole semisolid preparations composed of polysorbate 80, fatty acids and organic acids showed good solubility and dissolution when dispersed in an aqueous medium. It was anticipated that the semisolid dosage forms would be industrially applicable to improving the bioavailability of poorly water-soluble drugs. PMID:17146976

  15. Chemical and mineralogical characterizations of LD converter steel slags: A multi-analytical techniques approach

    SciTech Connect

    Waligora, J.; Bulteel, D.; Degrugilliers, P.; Damidot, D.; Potdevin, J.L.; Measson, M.

    2010-01-15

    The use of LD converter steel slags (coming from Linz-Donawitz steelmaking process) as aggregates in road construction can in certain cases lead to dimensional damage due to a macroscopic swelling that is the consequence of chemical reactions. The aim of this study was to couple several analytical techniques in order to carefully undertake chemical and mineralogical characterizations of LD steel slags and identify the phases that are expected to be responsible for their instability. Optical microscopy, scanning electron microscopy and electron probe microanalyses revealed that LD steel slags mainly contain calcium silicates, dicalcium ferrites, iron oxides and lime. However, as a calcium silicate phase is heterogeneous, Raman microspectrometry and transmitted electron microscopy had to be used to characterize it more precisely. Results showed that lime is present under two forms in slag grains: some nodules observed in the matrix whose size ranges from 20 to 100 {mu}m and some micro-inclusions, enclosed in the heterogeneous calcium silicate phase whose size ranges from 1 to 3 {mu}m. It was also established that without the presence of magnesia, lime is expected to be the only phase responsible for LD steel slags instability. Nevertheless, the distribution of lime between nodules and micro-inclusions may play a major role and could explain that similar amounts of lime can induce different instabilities. Thus, it appears that lime content of LD steel slags is not the only parameter to explain their instability.

  16. Laser ultrasound technique applied in material characterization of thermally sprayed nickel aluminum coatings

    NASA Astrophysics Data System (ADS)

    Yeh, C. H.; Yang, C. H.; Hsiao, W. T.; Su, C.-Y.

    2012-05-01

    Thermal spraying processing usually uses a nickel-aluminum alloy system as the major powder due to its strong adhesion to substrates. The contents of powder material and the processing parameters used in the spraying process cause material properties of coatings exhibiting a wide variation. This research aims at nondestructive characterization of thermal spraying coatings. A laser-generation/laser-detection laser ultrasound technique (LUT) is used for the measurements of dispersion spectra of surface waves propagating along the coated surfaces. Theoretical model for surface waves propagating along a multi-layered structure with coating and substrate is used to model the sprayed coatings. An inversion algorithm based on Shuffled Complex Evolution (SCE-UA) is used to extract mechanical properties from the measured dispersion spectra cooperating with theoretical model. Three coatings with different sprayed powders and powder processing are investigated. Results indicate that substantial linear scatterings are observed for the inverted properties due to the measured dispersion spectra with limited bandwidth inherited from the relatively high attenuations. The slope of linear scattering can be used to distinguish the coating properties. The ANiBNb sample with ball-milled coating has the best properties based on its highest velocity and least attenuation. This method is potentially useful to characterize the mechanical properties of thermally spraying coating in a nondestructive way.

  17. Preparation and characterization of hydroxyapatite-coated iron oxide particles by spray-drying technique.

    PubMed

    Donadel, Karina; Felisberto, Marcos D V; Laranjeira, Mauro C M

    2009-06-01

    Magnetic particles of iron oxide have been increasingly used in medical diagnosis by magnetic resonance imaging and in cancer therapies involving targeted drug delivery and magnetic hyperthermia. In this study we report the preparation and characterization of iron oxide particles coated with bioceramic hydroxyapatite by spray-drying. The iron oxide magnetic particles (IOMP) were coated with hydroxyapatite (HAp) by spray-drying using two IOMP/HAp ratios (0.7 and 3.2). The magnetic particles were characterized by way of scanning electronic microscopy, energy dispersive X-ray, X-ray diffraction, Fourier transformed infrared spectroscopy, flame atomic absorption spectrometry,vibrating sample magnetometry and particle size distribution (laser diffraction). The surface morphology of the coated samples is different from that of the iron oxide due to formation of hydroxyapatite coating. From an EDX analysis, it was verified that the surface of the coated magnetic particles is composed only of HAp, while the interior containsiron oxide and a few layers of HAp as expected. The results showed that spray-drying technique is an efficient and relatively inexpensive method for forming spherical particles with a core/shell structure. PMID:19488622

  18. Electrical characterization of grain boundaries of CZTS thin films using conductive atomic force microscopy techniques

    SciTech Connect

    Muhunthan, N.; Singh, Om Pal; Toutam, Vijaykumar; Singh, V.N.

    2015-10-15

    Graphical abstract: Experimental setup for conducting AFM (C-AFM). - Highlights: • Cu{sub 2}ZnSnS{sub 4} (CZTS) thin film was grown by reactive co-sputtering. • The electronic properties were probed using conducting atomic force microscope, scanning Kelvin probe microscopy and scanning capacitance microscopy. • C-AFM current flow mainly through grain boundaries rather than grain interiors. • SKPM indicated higher potential along the GBs compared to grain interiors. • The SCM explains that charge separation takes place at the interface of grain and grain boundary. - Abstract: Electrical characterization of grain boundaries (GB) of Cu-deficient CZTS (Copper Zinc Tin Sulfide) thin films was done using atomic force microscopic (AFM) techniques like Conductive atomic force microscopy (CAFM), Kelvin probe force microscopy (KPFM) and scanning capacitance microscopy (SCM). Absorbance spectroscopy was done for optical band gap calculations and Raman, XRD and EDS for structural and compositional characterization. Hall measurements were done for estimation of carrier mobility. CAFM and KPFM measurements showed that the currents flow mainly through grain boundaries (GB) rather than grain interiors. SCM results showed that charge separation mainly occurs at the interface of grain and grain boundaries and not all along the grain boundaries.

  19. High-resolution accurate mass spectrometry as a technique for characterization of complex lysimeter leachate samples.

    PubMed

    Hand, Laurence H; Marshall, Samantha J; Saeed, Mansoor; Earll, Mark; Hadfield, Stephen T; Richardson, Kevan; Rawlinson, Paul

    2016-06-01

    Lysimeter studies can be used to identify and quantify soil degradates of agrochemicals (metabolites) that have the potential to leach to groundwater. However, the apparent metabolic profile of such lysimeter leachate samples will often be significantly more complex than would be expected in true groundwater samples. This is particularly true for S-metolachlor, which has an extremely complex metabolic pathway. Consequently, it was not practically possible to apply a conventional analytical approach to identify all metabolites in an S-metolachlor lysimeter study, because there was insufficient mass to enable the use of techniques such as nuclear magnetic resonance. Recent advances in high-resolution accurate mass spectrometry, however, allow innovative screening approaches to characterize leachate samples to a greater extent than previously possible. Leachate from the S-metolachlor study was screened for accurate masses (±5 ppm of the nominal mass) corresponding to more than 400 hypothetical metabolite structures. A refined list of plausible metabolites was constructed from these data to provide a comprehensive description of the most likely metabolites present. The properties of these metabolites were then evaluated using a principal component analysis model, based on molecular descriptors, to visualize the entire chemical space and to cluster the metabolites into a number of subclasses. This characterization and principal component analysis evaluation enabled the selection of suitable representative metabolites that were subsequently used as exemplars to assess the toxicological relevance of the leachate as a whole. Environ Toxicol Chem 2016;35:1401-1412. © 2015 SETAC. PMID:26627902

  20. Fundamental characterization of shrink techniques on negative tone development based dense contact holes

    NASA Astrophysics Data System (ADS)

    Jain, Kaveri; Light, Scott L.

    2016-03-01

    Enormous advances have been made in recent years to design sub 40nm dense contact hole pattern with local CD uniformity (CDU) that the process can tolerate. Negative tone development process (NTD) on 193nm photoresists has achieved this to a large extent without the requirement of additional processing steps on the patterned layer. With further shrinking of size of the subsequent nodes, the demand to produce smaller patterns with wider process window, low defectivity, and improved CDU is increasing, and reaching beyond what can be achieved through NTD alone. A number of techniques are in practice today to achieve this, most notably, implementation of a collar of Atomic Layer Deposited SiO2 (ALD) on photoresist or substrate. However, in recent years, various material suppliers have also proposed shrink chemistries to achieve this. In this paper, we have provided fundamental characterization of shrink via application of spin-on agents (organic as well as aqueous) on the post-imaged pattern. We have also compared them for their shrink capacity, defect tendency, dry etch capability and ease of implementation in the process flow. In addition, we have provided recommendations on which technique is suitable for a given set of process prerequisites.

  1. Operando characterization of nanocatalysts via spectroscopy, scattering and imaging techniques in the same micro-reactor

    NASA Astrophysics Data System (ADS)

    Li, Yuanyuan; Frenkel, Anatoly; Baumann, Philipp; Tappero, Ryan; Zakharov, Dmitri; Stach, Eric; Elsen, Annika; Jung, Ulrich; Nuzzo, Ralph

    2014-03-01

    The increasing demand to rationally design new catalysts for energy generation/conversion calls for improvements in research methodology which enables multi-technique investigations of working catalysts in reaction conditions. Using the operando approach is necessary to establish structure activity/selectivity relationship. However, this approach is hindered by many challenges, e.g., the incompatibility of different characterization methods with respect to the sample concentration and environment, and, hence, the need to use multiple in situ reactor designs. We report on the development and tests of the single, portable reactor compatible with most useful techniques for operando studies of nanocatalysts: X-ray absorption, transmission electron microscopy, infrared and Raman spectroscopies. The test system was Pt/SiO2 nanocatalyst and the reaction was the ethylene hydrogenation. The reactor was a closed cell with SiN windows enabled catalytic reactions under atmospheric pressure. Both XAFS and TEM experiments were conducted in identical conditions, while monitoring the product formation using mass spectrometry. Comparison of TEM and XAFS results provided new information on the structure-activity relationship of these catalysts.

  2. Characterization and bioactivity study of nanohydroxyapatite on superhydrophilic vertically aligned carbon nanotubes using optical techniques

    NASA Astrophysics Data System (ADS)

    Ferreira Irineu, Joao Anderson; Marsi, Teresa C.; Santos, Tiago G.; Santo, Ana Maria E.; Rangel, Joao L.; Mengui, Ursula A.; Martin, Airton A.; Corat, Evaldo J.; Marciano, Fernanda R.; Lobo, Anderson O.

    2012-03-01

    Vertically-aligned multi-walled carbon nanotubes (VACNT) is of particular interest in regenerative medicine. Templateinduced hydroxyapatite (HA) has broad prospects in applied fields of bone regenerative medicine. Thus, it becomes very attractive a combination these two excellent materials to bone tissue engineering applications. In this study the HA/VACNT nanocomposites were used as scaffolds to Human osteoblast cells culture. Superhydrophilic VACNT films were obtained by CVD method and funcionalized by oxygen plasma. The fabrication of HA/VACNT nanocomposites was performed with a direct electrodeposition of the thin HA films on the VACNT films. The bioactivity and biomineralization in vitro process of superhydrophilic HA/VACNT nanocomposites were investigated using simulated body fluid (SBF) and optical techniques. The characterization of of HA/VACNT nanocomposites was performed before and after soaking 21 days in SBF and compared to superydrophilic VACNT films. Fourier transform infrared spectroscopy, micro X-ray fluorescence spectrometer by energy-dispersive and X-ray difractogram were employed to investigate the structural and chemical properties. The morphology was investigated by FEG-SEM analysis. After 21 days was identified that others biological apatites were formed only on HA/VACNT nanocomposites. Optical techniques showing a powerful tool to characterizated and investigated the bioactivity in vitro process. These findings were very atractive to application of this new nanocomposite to bone tissue regeneration.

  3. Ultrasonic Nondestructive Evaluation Techniques Applied to the Quantitative Characterization of Textile Composite Materials

    NASA Technical Reports Server (NTRS)

    Miller, James G.

    1998-01-01

    An overall goal of this research has been to enhance our understanding of the scientific principles necessary to develop advanced ultrasonic nondestructive techniques for the quantitative characterization of advanced composite structures. To this end, we have investigated a thin woven composite (5-harness biaxial weave). We have studied the effects that variations of the physical parameters of the experimental setup can have on the ultrasonic determination of the material properties for this thin composite. In particular, we have considered the variation of the nominal center frequency and the f-number of the transmitting transducer which in turn address issues such as focusing and beam spread of ultrasonic fields. This study has employed a planar, two-dimensional, receiving pseudo-array that has permitted investigation of the diffraction patterns of ultrasonic fields. Distortion of the ultrasonic field due to the spatial anisotropy of the thin composite has prompted investigation of the phenomenon of phase cancellation at the face of a finite-aperture, piezoelectric receiver. We have performed phase-sensitive and phase-insensitive analyses to provide a measure of the amount of phase cancellation at the face of a finite-aperture, piezoelectric receiver. The pursuit of robust measurements of received energy (i.e., those not susceptible to phase cancellation at the face of a finite-aperture, piezoelectric receiver) supports the development of robust techniques to determine material properties from measure ultrasonic parameters.

  4. Development of DNA affinity techniques for the functional characterization of purified RNA polymerase II transcription factors

    SciTech Connect

    Garfinkel, S.; Thompson, J.A.; Cohen, R.B.; Brendler, T.; Safer, B.

    1987-05-01

    Affinity adsorption, precipitation, and partitioning techniques have been developed to purify and characterize RNA Pol II transcription components from whole cell extracts (WCE) (HeLa) and nuclear extracts (K562). The titration of these extracts with multicopy constructs of the Ad2 MLP but not pUC8, inhibits transcriptional activity. DNA-binding factors precipitated by this technique are greatly enriched by centrifugation. Using this approach, factors binding to the upstream promoter sequence (UPS) of the Ad2 MLP have been rapidly isolated by Mono Q, Mono S, and DNA affinity chromatography. By U.V. crosslinking to nucleotides containing specific TSP-phosphodiester bonds within the recognition sequence, this factor is identified as a M/sub r/ = 45,000 polypeptide. To generate an assay system for the functional evaluation of single transcription components, a similar approach using synthetic oligonucleotide sequences spanning single promoter binding sites has been developed. The addition of a synthetic 63-mer containing the UPS element of the Ad2 MLP to HeLa WCE inhibited transcription by 60%. The addition of partially purified UPS binding protein, but not RNA Pol II, restored transcriptional activity. The addition of synthetic oligonucleotides containing other regulatory sequences not present in the Ad2 MLP was without effect.

  5. Characterization of (Th,U)O 2 fuel pellets made by impregnation technique

    NASA Astrophysics Data System (ADS)

    Kutty, T. R. G.; Nair, M. R.; Sengupta, P.; Basak, U.; Kumar, Arun; Kamath, H. S.

    2008-02-01

    Impregnation technique is an attractive alternative for manufacturing highly radiotoxic 233U bearing thoria based mixed oxide fuel pellets, which are remotely treated in hot cell or shielded glove-box facilities. This technique is being investigated to fabricate the fuel for the forthcoming Indian Advanced Heavy Water Reactor (AHWR). In the impregnation process, porous ThO 2 pellets are prepared in an unshielded facility which are then impregnated with 1.5 molar uranyl nitrate solution in a shielded facility. The resulting composites are dried and denitrated at 500 °C and then sintered in reducing/oxidizing atmosphere to obtain high density (Th,U)O 2 pellets. In this work, the densification behaviour of ThO 2-2% UO 2 and ThO 2-4% UO 2 pellets was studied in reducing and oxidizing atmospheres using a high temperature dilatometer. Densification was found to be larger in air than in Ar-8% H 2. The characterization of the sintered pellets was made by optical microscopy, scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). The grain structure of ThO 2-2% UO 2 and ThO 2-4% UO 2 pellets was uniform. The EPMA data confirmed that the uranium concentration was slightly higher at the periphery of the pellet than that at the centre.

  6. Comparative analysis of different measurement techniques for characterizing soil surface roughness in agricultural soils

    NASA Astrophysics Data System (ADS)

    Martinez-Agirre, Alex; Álvarez-Mozos, Jesús; Valle, José Manuel; Rodríguez, Álvaro; Giménez, Rafael

    2016-04-01

    analysis was threefold: (1) comparison of raw data (point clouds), (2) comparison of interpolated DEMs considering different resolutions (2.5mm, 5mm and 10mm) and (3) comparison of roughness parameters. In all cases the profilometer was used as a reference because of its vertical accuracy and nadiral viewing geometry. Thus point clouds and interpolated DEMs were compared to the height profiles. The results showed that in most cases surface height discrepancies were below 10 mm for raw data and increased slightly when increasing the pixel size of DEMs. Finally, a thorough analysis of different roughness parameters proposed in the literature was carried out to find the most appropriate technique and parameter for the characterization of roughness in each case. Although still preliminary, results offer practical recommendations on the usefulness of each technique.

  7. Embedded fiber optic sensors for monitoring processing, quality and structural health of resin transfer molded components

    NASA Astrophysics Data System (ADS)

    Keulen, C.; Rocha, B.; Yildiz, M.; Suleman, A.

    2011-07-01

    Due to their small size and flexibility fiber optics can be embedded into composite materials with little negative effect on strength and reliability of the host material. Fiber optic sensors such as Fiber Bragg Gratings (FBG) or Etched Fiber Sensors (EFS) can be used to detect a number of relevant parameters such as flow, degree of cure, quality and structural health throughout the life of a composite component. With a detection algorithm these embedded sensors can be used to detect damage in real time while the component remains in service. This paper presents the research being conducted on the use of fiber optic sensors for process and Structural Health Monitoring (SHM) of Resin Transfer Molded (RTM) composite structures. Fiber optic sensors are used at all life stages of an RTM composite panel. A laboratory scale RTM apparatus was developed with the capability of visually monitoring the resin filling process. A technique for embedding fiber optic sensors with this apparatus has also been developed. Both FBGs and EFSs have been embedded in composite panels using the apparatus. EFSs to monitor the fabrication process, specifically resin flow have been embedded and shown to be capable of detecting the presence of resin at various locations as it is injected into the mold. Simultaneously these sensors were multiplexed on the same fiber with FBGs, which have the ability to measure strain. Since multiple sensors can be multiplexed on a single fiber the number of ingress/egress locations required per sensor can be significantly reduced. To characterize the FBGs for strain detection tensile test specimens with embedded FBG sensors have been produced. These specimens have been instrumented with a resistive strain gauge for benchmarking. Both specimens and embedded sensors were characterized through tensile testing. Furthermore FBGs have been embedded into composite panels in a manner that is conducive to detection of Lamb waves generated with a centrally located PZT

  8. Applied Protein and Molecular Techniques for Characterization of B Cell Neoplasms in Horses

    PubMed Central

    Badial, Peres R.; Tallmadge, Rebecca L.; Miller, Steven; Stokol, Tracy; Richards, Kristy; Borges, Alexandre S.

    2015-01-01

    Mature B cell neoplasms cover a spectrum of diseases involving lymphoid tissues (lymphoma) or blood (leukemia), with an overlap between these two presentations. Previous studies describing equine lymphoid neoplasias have not included analyses of clonality using molecular techniques. The objective of this study was to use molecular techniques to advance the classification of B cell lymphoproliferative diseases in five adult equine patients with a rare condition of monoclonal gammopathy, B cell leukemia, and concurrent lymphadenopathy (lymphoma/leukemia). The B cell neoplasms were phenotypically characterized by gene and cell surface molecule expression, secreted immunoglobulin (Ig) isotype concentrations, Ig heavy-chain variable (IGHV) region domain sequencing, and spectratyping. All five patients had hyperglobulinemia due to IgG1 or IgG4/7 monoclonal gammopathy. Peripheral blood leukocyte immunophenotyping revealed high proportions of IgG1- or IgG4/7-positive cells and relative T cell lymphopenia. Most leukemic cells lacked the surface B cell markers CD19 and CD21. IGHG1 or IGHG4/7 gene expression was consistent with surface protein expression, and secreted isotype and Ig spectratyping revealed one dominant monoclonal peak. The mRNA expression of the B cell-associated developmental genes EBF1, PAX5, and CD19 was high compared to that of the plasma cell-associated marker CD38. Sequence analysis of the IGHV domain of leukemic cells revealed mutated Igs. In conclusion, the protein and molecular techniques used in this study identified neoplastic cells compatible with a developmental transition between B cell and plasma cell stages, and they can be used for the classification of equine B cell lymphoproliferative disease. PMID:26311245

  9. Use of microfocus computerized tomography as a new technique for characterizing bone tissue around oral implants.

    PubMed

    Van Oossterwyck, H; Duyck, J; Vander Sloten, J; Van der Perre, G; Jansen, J; Wevers, M; Naert, I

    2000-01-01

    Qualitative and quantitative analysis of peri-implant tissues around retrieved oral implants is typically done by means of light microscopy on thin histological sections containing the metal surface and the undecalcified bone. It remains, however, a labor-intensive and thus time-consuming job. Moreover, it is a destructive technique that allows tissue quantification in only a limited number of two-dimensional sections. As an alternative, we evaluated the bone structure around screw-shaped titanium implants by means of microfocus computerized tomography (micro-CT) because it presents a number of advantages compared to conventional sectioning techniques: micro-CT is nondestructive, fast, and allows a fully three-dimensional characterization of the bone structure around the implant. Images can be reconstructed in an arbitrary plane, and three-dimensional reconstructions are also possible. Because of its high resolution, individual trabeculae can be visualized. The accuracy of micro-CT was qualitatively evaluated by comparing histological sections with the corresponding CT slices for the same specimen. The overall trabecular structure is very similar according to both techniques. Even very close to the interface, the titanium implant does not seem to produce significant artifacts. Furthermore, because the complete digital data on the trabecular bone structure around the implant is available, it is possible to create finite-element models of the bone-implant system that model the trabeculae in detail so that mechanical stress transfer at the interface can be studied at the level of individual trabeculae. Therefore, micro-CT seems to be very promising for the in vitro assessment of the three-dimensional bone structure around oral implants. Further research will be needed to evaluate its accuracy in a more quantitative way. PMID:11831302

  10. Threading Dislocation Characterization and Stress Mapping Depth Profiling via Ray Tracing Technique

    NASA Astrophysics Data System (ADS)

    Zhou, Tianyi

    Zinc oxide (ZnO) has been well known as a transparent, dielectric, piezoelectric and wide band gap material. The potential capabilities have been demonstrated for a wide range of applications such as piezoelectric transducer, gas sensor, optical waveguides and transparent electrode. It could also be applied as a substrate material for GaN-based devices. However, while some applications have already been realized, issues relating to crystalline defects remain a barrier to the successful realization of several others. In this thesis, the central focus of Chapter II is to characterize threading dislocations in hydrothermal grown ZnO substrates through simulation work as well as other techniques. The goal of this study is to find the origin of threading dislocations and design strategies to mitigate their negative effects by either reducing their densities or completely eliminating them. In Chapter III, the technique of SMART (stress mapping analysis via ray tracing) is discussed in detail to measure residue stress in packaged silicon circuits. Residual stress plays an important role in the performance and lifetime of single crystal device material. There are mainly two advantages of SMART compared with other techniques: (a) all six components of the stress tensor could be evaluated; (b) it is non-destructive and no damaging trace will be left on the sample. In this study, our goal is to build a relationship between stress distribution and depth. The concept of penetration depth is critically important in this study and its value may cause great changes for real space stress distribution. A new function is applied to get better fitting curves. Data in this study is obtained from various penetration depth, which represents exponentially decaying weighted average of actual stress value or in other words this stress profile is Laplace transform of real stress profile. Mathematical procedure is described to determine real stress profile from Laplace profile. Experiment

  11. Bio-Impedance Characterization Technique with Implantable Neural Stimulator Using Biphasic Current Stimulus

    PubMed Central

    Lo, Yi-Kai; Chang, Chih-Wei; Liu, Wentai

    2016-01-01

    Knowledge of the bio-impedance and its equivalent circuit model at the electrode-electrolyte/tissue interface is important in the application of functional electrical stimulation. Impedance can be used as a merit to evaluate the proximity between electrodes and targeted tissues. Understanding the equivalent circuit parameters of the electrode can further be leveraged to set a safe boundary for stimulus parameters in order not to exceed the water window of electrodes. In this paper, we present an impedance characterization technique and implement a proof-of-concept system using an implantable neural stimulator and an off-the-shelf microcontroller. The proposed technique yields the parameters of the equivalent circuit of an electrode through large signal analysis by injecting a single low-intensity biphasic current stimulus with deliberately inserted inter-pulse delay and by acquiring the transient electrode voltage at three well-specified timings. Using low-intensity stimulus allows the derivation of electrode double layer capacitance since capacitive charge-injection dominates when electrode overpotential is small. Insertion of the inter-pulse delay creates a controlled discharge time to estimate the Faradic resistance. The proposed method has been validated by measuring the impedance of a) an emulated Randles cells made of discrete circuit components and b) a custom-made platinum electrode array in-vitro, and comparing estimated parameters with the results derived from an impedance analyzer. The proposed technique can be integrated into implantable or commercial neural stimulator system at low extra power consumption, low extra-hardware cost, and light computation. PMID:25569999

  12. Characterization of corrosion pit initiation in aluminum using advanced electron microscopy techniques

    NASA Astrophysics Data System (ADS)

    Elswick, Danielle S.

    The resistance to pitting corrosion in aluminum is due to the presence of a compact thin, approximately 5 nm, oxide. Certain conditions locally attack this protective oxide layer leading to its breakdown and resulting in the formation of corrosion pits. Numerous studies have investigated the growth and propagation stages of pitting corrosion yet the initiation stage remains not clearly defined nor well understood. The presence of aggressive chemical species, such as chloride, plays a critical role in the pitting phenomenon and is explored in this investigation. This dissertation focuses on the localization of pitting corrosion in high purity aluminum in order to accurately predict where and when the pit initiation process will occur so that microstructural changes associated with pit initiation can be easily identified and characterized using electron microscopy. A comprehensive investigation into the corrosion initiation process was attempted utilizing advanced characterization techniques in the transmission electron microscope (TEM) coupled with high-resolution microanalysis. Localization of pitting was successful through use of different sample geometries that reduced the length scale for which pitting events occurred. Three geometries were investigated, each with unique features for pitting corrosion. Electropolished Al needles localized pitting to a sharp tip due to a geometric field enhancement effect, while other experiments employed an Al wire micro-electrode geometry. Both geometries minimized the area where corrosion pits initiated and were electrochemically tested using a solution that contained the chloride species. A third geometry included electron beam evaporated Al films implanted with chloride, which induced pitting corrosion in an otherwise chloride-free environment. Localization of pitting was successfully achieved using novel sample geometries that isolated the desired stages of pitting corrosion, i.e. metastable pitting, through controlled

  13. Characterization of Deficiencies in the Frequency Domain Forced Response Analysis Technique for Supersonic Turbine Bladed Disks

    NASA Technical Reports Server (NTRS)

    Brown, Andrew M.; Schmauch, Preston

    2011-01-01

    Turbine blades in rocket and jet engine turbomachinery experience enormous harmonic loading conditions. These loads result from the integer number of upstream and downstream stator vanes as well as the other turbine stages. Assessing the blade structural integrity is a complex task requiring an initial characterization of whether resonance is possible and then performing a forced response analysis if that condition is met. The standard technique for forced response analysis in rocket engines is to decompose a CFD-generated flow field into its harmonic components, and to then perform a frequency response analysis at the problematic natural frequencies. Recent CFD analysis and water-flow testing at NASA/MSFC, though, indicates that this technique may miss substantial harmonic and non-harmonic excitation sources that become present in complex flows. A substantial effort has been made to account for this denser spatial Fourier content in frequency response analysis (described in another paper by the author), but the question still remains whether the frequency response analysis itself is capable of capturing the excitation content sufficiently. Two studies comparing frequency response analysis with transient response analysis, therefore, of bladed-disks undergoing this complex flow environment have been performed. The first is of a bladed disk with each blade modeled by simple beam elements. Six loading cases were generated by varying a baseline harmonic excitation in different ways based upon cold-flow testing from Heritage Fuel Air Turbine Test. It was hypothesized that the randomness and other variation from the standard harmonic excitation would reduce the blade structural response, but the results showed little reduction. The second study was of a realistic model of a bladed-disk excited by the same CFD used in the J2X engine program. It was hypothesized that enforcing periodicity in the CFD (inherent in the frequency response technique) would overestimate the

  14. Laboratory instrumentation and techniques for characterizing multi-junction solar cells for space applications

    NASA Technical Reports Server (NTRS)

    Woodyard, James R.

    1995-01-01

    Multi-junction solar cells are attractive for space applications because they can be designed to convert a larger fraction of AMO into electrical power at a lower cost than single-junction cells. The performance of multi-junction cells is much more sensitive to the spectral irradiance of the illuminating source than single-junction cells. The design of high efficiency multi-junction cells for space applications requires matching the optoelectronic properties of the junctions to AMO spectral irradiance. Unlike single-junction cells, it is not possible to carry out quantum efficiency measurements using only a monochromatic probe beam and determining the cell short-circuit current assuming linearity of the quantum efficiency. Additionally, current-voltage characteristics can not be calculated from measurements under non-AMO light sources using spectral-correction methods. There are reports in the literature on characterizing the performance of multi junction cells by measuring and convoluting the quantum efficiency of each junction with the spectral irradiance; the technique is of limited value for the characterization of cell performance under AMO power-generating conditions. We report the results of research to develop instrumentation and techniques for characterizing multi junction solar cells for space . An integrated system is described which consists of a standard lamp, spectral radiometer, dual-source solar simulator, and personal computer based current-voltage and quantum efficiency equipment. The spectral radiometer is calibrated regularly using the tungsten-halogen standard lamp which has a calibration based on NIST scales. The solar simulator produces the light bias beam for current-voltage and cell quantum efficiency measurements. The calibrated spectral radiometer is used to 'fit' the spectral irradiance of the dual-source solar simulator to WRL AMO data. The quantum efficiency apparatus includes a monochromatic probe beam for measuring the absolute cell

  15. Silica Embedded Metal Hydrides

    SciTech Connect

    Heung, L.K.; Wicks, G.G.

    1998-08-01

    A method to produce silica embedded metal hydride was developed. The product is a composite in which metal hydride particles are embedded in a matrix of silica. The silica matrix is highly porous. Hydrogen gas can easily reach the embedded metal hydride particles. The pores are small so that the metal hydride particles cannot leave the matrix. The porous matrix also protects the metal hydride particles from larger and reactive molecules such as oxygen, since the larger gas molecules cannot pass through the small pores easily. Tests show that granules of this composite can absorb hydrogen readily and withstand many cycles without making fines.

  16. Characterization and Processing of Organic Nonlinear Optical Materials using Ellipsometric, Waveguiding, and Absorption Spectroscopy Techniques

    NASA Astrophysics Data System (ADS)

    Olbricht, Benjamin C.

    The first focus of this work is to describe methods for characterizing organic electro-optic materials. Teng-Man Ellipsometry and Attenuated Total Internal Reflection are reviewed. Experimental techniques for these instruments are described and the calculation of an electro-optic activity is derived. The two techniques are compared; it has been found that in Situ Teng-Man ellipsometry is useful to determine poling conditions but not for reliably evaluating electro-optic activity. Attenuated Total Internal Reflection is found to provide very reliable and precise measurements of electro-optic activity and linear optical constants. As a reference, many materials systems have been evaluated and their electro-optic activities are recorded herein. Methods for fabricating devices for test by Teng-Man ellipsometry and Attenuated Total Internal Reflection are presented. A process for inducing Pockel's response via contact-geometry electric field poling is also described, along with modifications to the simple slab dielectric device to enhance the efficacy of poling. An additional method for enhancing the efficiency of poling is presented. This technique relies on the photoisomerization of azobenzene dyes under 532nm radiation to reduce the dimensionality accessible to chromophores doped into the azobenzene matrix. This effect is known as "Laser Assisted Poling" and is shown to increase poling efficiency by more than two fold. The second purpose of this work is to present an experimental technique to measure the order parameter = 3cos 2q -12 . This method is known as Variable-Angle Polarization-Referenced Absorption Spectroscopy (VAPRAS). The experimental apparatus used for VAPRAS introduces small alterations to a UV/Vis Spectrophotometer and an order parameter is derived by exclusively using classical models for transmittance. VAPRAS provides an effective refractive index for the electro-optic material film which is used to calculate the order of absorbers in the film

  17. Potential and limitations of microanalysis SEM techniques to characterize borides in brazed Ni-based superalloys

    SciTech Connect

    Ruiz-Vargas, J.; Siredey-Schwaller, N.; Noyrez, P.; Mathieu, S.; Bocher, P.; and others

    2014-08-15

    Brazed Ni-based superalloys containing complex phases of different Boron contents remain difficult to characterize at the micrometer scale. Indeed Boron is a light element difficult to measure precisely. The state-of-the-art microanalysis systems have been tested on a single crystal MC2 based metal brazed with BNi-2 alloy to identify boride precipitates. Effort has been made to evaluate the accuracy in Boron quantitation. Energy-dispersive and wavelength-dispersive X-ray spectroscopy attached to a Scanning Electron Microscope have first been used to determine the elemental composition of Boron-free phases, and then applied to various types of borides. Results have been compared to the ones obtained using a dedicated electron probe microanalysis, considered here as the reference technique. The most accurate method to quantify Boron using EDS is definitely by composition difference. A precision of 5 at.% could be achieved with optimized data acquisition and post-processing schemes. Attempts that aimed at directly quantifying Boron with various standards using EDS or coupled EDS/WDS gave less accurate results. Ultimately, Electron Backscatter Diffraction combined with localized EDS analysis has proved invaluable in conclusively identifying micrometer sized boride precipitates; thus further improving the characterization of brazed Ni-based superalloys. - Highlights: • We attempt to accurately identify Boron-rich phases in Ni-based superalloys. • EDS, WDS, EBSD systems are tested for accurate identification of these borides. • Results are compared with those obtained by electron probe microanalysis. • Boron was measured with EDS by composition difference with a precision of 5 at. %. • Additional EBSD in phase identification mode conclusively identifies the borides.

  18. Hydrogeologic facies characterization of an alluvial fan near Fresno, California, using geophysical techniques

    USGS Publications Warehouse

    Burow, Karen R.; Weissmann, G.S.; Miller, R.D.; Placzek, Gary

    1997-01-01

    DBCP (1,2-dibromo-3-chloropropane) contamination in the sole source aquifer near Fresno, California, has significantly affected drinking-water supplies. Borehole and surface geophysical data were integrated with borehole textural data to characterize the Kings River alluvial fan sediments and to provide a framework for computer modeling of pesticide transport in ground water. Primary hydrogeologic facies units, such as gravel, coarse sand or gravel, fine sand, and silt and clay, were identified in cores collected from three borings located on a 4.6-kilometer transect of multilevel monitoring wells. Borehole geophysical logs collected from seven wells and surface geophysical surveys were used to extrapolate hydrogeologic facies to depths of about 82meters and to correlate the facies units with neighboring drilling sites. Thickness ranged from 0.3to 13 meters for sand and gravel units, and from 0.3 to 17 meters for silt and clay. The lateral extent of distinct silt and clay layers was mapped using shallow seismic reflection and ground-penetrating radar techniques. About 3.6 kilometers of seismic reflection data were collected; at least three distinct fine-grained layers were mapped. The depth of investigation of the seismic survey ranged from 34 to 107 meters below land surface, and vertical resolution was about 3.5 meters. The ground-penetrating radar survey covered 3.6kilometers and imaged a 1.5-meters thick, continuous fine-grained layer located at a depth of about 8 meters. Integrated results from the borehole sediment descriptions and geophysical surveys provided a detailed characterization over a larger areal extent than traditional hydrogeologic methods alone.

  19. Zone wise local characterization of welds using digital image correlation technique

    NASA Astrophysics Data System (ADS)

    Saranath, K. M.; Sharma, Abhay; Ramji, M.

    2014-12-01

    The process of welding is associated with high and varying thermal gradients across the weld, resulting in inhomogeneous material properties surrounding the weldment. A proper understanding of the varying mechanical properties of the weld and surrounding materials is important in designing and modelling of components with weld. In the present study the characterization of different zones such as fusion zone, heat affected zones and unaffected base material of a deposited weld is carried out using digital image correlation (DIC) technique. A methodology using the micrographic observation and image processing is proposed for accurate identification of various weld zones. The response of welded samples in the elastic and plastic region is compared with the virgin sample. Full range stress-strain curves are obtained for each zone using the whole field strain measurement involving DIC. The parameters investigated are Young's modulus, Poisson's ratio, yield stress, strain hardening exponent and strength coefficient. A study regarding the variation of properties with respect to varying weld currents of 100 A, 130 A and 150 A is carried out. The Vickers microhardness measurement is also conducted to obtain the variation in hardness across weldment. Fusion zone of all the welded samples have reported lower Young's modulus and higher yield strength compared to virgin samples. The Vickers hardness values obtained for fusion and heat affected zones are in line with the yield stress variation obtained zone wise. Proposed zone wise local characterization of welds using digital image correlation. Weld zones are identified using a strain based method coupled with micrographs. Full range stress-strain curves are extracted for each local weld zones. Local elastic, plastic properties and microhardness across the weld are extracted. Local properties of welds produced using different current ratings are compared.

  20. Imaging as characterization techniques for thin-film cadmium telluride photovoltaics

    NASA Astrophysics Data System (ADS)

    Zaunbrecher, Katherine

    The goal of increasing the efficiency of solar cell devices is a universal one. Increased photovoltaic (PV) performance means an increase in competition with other energy technologies. One way to improve PV technologies is to develop rapid, accurate characterization tools for quality control. Imaging techniques developed over the past decade are beginning to fill that role. Electroluminescence (EL), photoluminescence (PL), and lock-in thermography are three types of imaging implemented in this study to provide a multifaceted approach to studying imaging as applied to thin-film CdTe solar cells. Images provide spatial information about cell operation, which in turn can be used to identify defects that limit performance. This study began with developing EL, PL, and dark lock-in thermography (DLIT) for CdTe. Once imaging data were acquired, luminescence and thermography signatures of non-uniformities that disrupt the generation and collection of carriers were identified and cataloged. Additional data acquisition and analysis were used to determine luminescence response to varying operating conditions. This includes acquiring spectral data, varying excitation conditions, and correlating luminescence to device performance. EL measurements show variations in a cell's local voltage, which include inhomogeneities in the transparent-conductive oxide (TCO) front contact, CdS window layer, and CdTe absorber layer. EL signatures include large gradients, local reduction of luminescence, and local increases in luminescence on the interior of the device as well as bright spots located on the cell edges. The voltage bias and spectral response were analyzed to determine the response of these non-uniformities and surrounding areas. PL images of CdTe have not shown the same level of detail and features compared to their EL counterparts. Many of the signatures arise from reflections and severe inhomogeneities, but the technique is limited by the external illumination source used to

  1. Characterization of a constrained paired-view technique in iterative reconstruction for breast tomosynthesis

    SciTech Connect

    Wu, Gang; Yaffe, Martin J.; Mainprize, James G.

    2013-10-15

    Purpose: The order in which the projection views are employed in the reconstruction of tomosynthesis by iterative algorithms, such as simultaneous algebraic reconstruction technique and maximum likelihood, has a strong effect on the rate of convergence, accuracy, and the edge-blurring artifacts in the reconstructed image. The purpose of this investigation was to characterize and evaluate the effects of ordering schemes on image quality for breast tomosynthesis reconstruction and to explore a new constrained paired-view technique that could provide reduction of reconstruction artifacts. In this work, the authors compared several different ordering schemes and characterized the image quality and the formation of out-of-plane artifacts. Furthermore, a new normalization method is presented. It produces more accurate reconstructions with reduced artifacts comparing to the standard method of sequential ordering.Methods: In addition to visual assessment of image quality, several indices such as the signal-difference-to-noise ratio, the artifact-spread function, and the lesion detectability (d{sup ′}) were computed to quantitatively evaluate the effect of ordering scheme. The sets of breast tomosynthesis projection images were simulated for reconstruction; one set had uniform background (white noise only) and the other two contained both anatomic background and quantum noise. Clinical breast images were also studied for comparison.Results: The authors have quantified the image quality in reconstructed slices for a range of tumor sizes. The authors’ proposed method provides better performance for all of the metrics tested (contrast, d{sup ′}, and the level of artifacts) both for the uniform phantom case and in the presence of anatomical structure.Conclusions: The paired projection normalization provides better performance in the image quality of the reconstructed slices, and results in a lower level of artifacts in the Z direction. This implies that even a relatively

  2. Dynamic tensile characterization of a 4330-V steel with kolsky bar techniques.

    SciTech Connect

    Song, Bo; Antoun, Bonnie R.; Connelly, Kevin

    2010-09-01

    There has been increasing demand to understand the stress-strain response as well as damage and failure mechanisms of materials under impact loading condition. Dynamic tensile characterization has been an efficient approach to acquire satisfactory information of mechanical properties including damage and failure of the materials under investigation. However, in order to obtain valid experimental data, reliable tensile experimental techniques at high strain rates are required. This includes not only precise experimental apparatus but also reliable experimental procedures and comprehensive data interpretation. Kolsky bar, originally developed by Kolsky in 1949 [1] for high-rate compressive characterization of materials, has been extended for dynamic tensile testing since 1960 [2]. In comparison to Kolsky compression bar, the experimental design of Kolsky tension bar has been much more diversified, particularly in producing high speed tensile pulses in the bars. Moreover, instead of directly sandwiching the cylindrical specimen between the bars in Kolsky bar compression bar experiments, the specimen must be firmly attached to the bar ends in Kolsky tensile bar experiments. A common method is to thread a dumbbell specimen into the ends of the incident and transmission bars. The relatively complicated striking and specimen gripping systems in Kolsky tension bar techniques often lead to disturbance in stress wave propagation in the bars, requiring appropriate interpretation of experimental data. In this study, we employed a modified Kolsky tension bar, newly developed at Sandia National Laboratories, Livermore, CA, to explore the dynamic tensile response of a 4330-V steel. The design of the new Kolsky tension bar has been presented at 2010 SEM Annual Conference [3]. Figures 1 and 2 show the actual photograph and schematic of the Kolsky tension bar, respectively. As shown in Fig. 2, the gun barrel is directly connected to the incident bar with a coupler. The cylindrical

  3. Dynamic tensile characterization of a 4330 steel with kolsky bar techniques.

    SciTech Connect

    Song, Bo; Antoun, Bonnie R.; Connelly, Kevin

    2010-08-01

    There has been increasing demand to understand the stress-strain response as well as damage and failure mechanisms of materials under impact loading condition. Dynamic tensile characterization has been an efficient approach to acquire satisfactory information of mechanical properties including damage and failure of the materials under investigation. However, in order to obtain valid experimental data, reliable tensile experimental techniques at high strain rates are required. This includes not only precise experimental apparatus but also reliable experimental procedures and comprehensive data interpretation. Kolsky bar, originally developed by Kolsky in 1949 [1] for high-rate compressive characterization of materials, has been extended for dynamic tensile testing since 1960 [2]. In comparison to Kolsky compression bar, the experimental design of Kolsky tension bar has been much more diversified, particularly in producing high speed tensile pulses in the bars. Moreover, instead of directly sandwiching the cylindrical specimen between the bars in Kolsky bar compression bar experiments, the specimen must be firmly attached to the bar ends in Kolsky tensile bar experiments. A common method is to thread a dumbbell specimen into the ends of the incident and transmission bars. The relatively complicated striking and specimen gripping systems in Kolsky tension bar techniques often lead to disturbance in stress wave propagation in the bars, requiring appropriate interpretation of experimental data. In this study, we employed a modified Kolsky tension bar, newly developed at Sandia National Laboratories, Livermore, CA, to explore the dynamic tensile response of a 4330-V steel. The design of the new Kolsky tension bar has been presented at 2010 SEM Annual Conference [3]. Figures 1 and 2 show the actual photograph and schematic of the Kolsky tension bar, respectively. As shown in Fig. 2, the gun barrel is directly connected to the incident bar with a coupler. The cylindrical

  4. Influence of nanostructure composition on its morphometric characterization by different techniques.

    PubMed

    Carvalho Silva, Renata; Alexandre Muehlmann, Luis; Rodrigues Da Silva, Jaqueline; de Bentes Azevedo, Ricardo; Madeira Lucci, Carolina

    2014-09-01

    Morphometric characterization of nanoparticles is crucial to determine their biological effects and to obtain a formulation pattern. Determining the best technique requires knowledge of the particles being analyzed, the intended application of the particles, and the limitations of the techniques being considered. The aim of this article was to present transmission (TEM) and scanning (SEM) electron microscopy protocols for the analysis of two different nanostructures, namely polymeric nanoemulsion and poly(lactic-co-glycolic acid) (PLGA) nanoparticles, and to compare these results with conventional dynamic light scattering (DLS) measurements. The mean hydrodynamic diameter, the polydispersity index, and zeta potential of the nanostructures of polymeric nanoemulsion were 370.5 ± 0.8 nm, 0.133 ± 0.01, and -36.1 ± 0.15 mV, respectively, and for PLGA nanoparticles were 246.79 ± 5.03 nm, 0.096 ± 0.025, and -4.94 ± 0.86 mV, respectively. TEM analysis of polymeric nanoemulsion revealed a mean diameter of 374 ± 117 nm. SEM analysis showed a mean diameter of 368 ± 69 nm prior to gold coating and 448 ± 70 nm after gold coating. PLGA nanoparticles had a diameter of 131 ± 41.18 nm in TEM and 193 ± 101 nm in SEM. Morphologically, in TEM analysis, the polymeric nanoemulsions were spherical, with variable electron density, very few showing an electron-dense core and others an electron-dense surface. PLGA nanoparticles were round, with an electron-lucent core and electron-dense surface. In SEM, polymeric nanoemulsions were also spherical with a rough surface, and PLGA nanoparticles were round with a smooth surface. The results show that the "gold standards" for morphometric characterization of polymeric nanoemulsion and PLGA nanoparticles were, respectively, SEM without gold coating and TEM with negative staining. PMID:24919585

  5. Characterizing local traffic contributions to particulate air pollution in street canyons using mobile monitoring techniques

    NASA Astrophysics Data System (ADS)

    Zwack, Leonard M.; Paciorek, Christopher J.; Spengler, John D.; Levy, Jonathan I.

    2011-05-01

    Traffic within urban street canyons can contribute significantly to ambient concentrations of particulate air pollution. In these settings, it is challenging to separate within-canyon source contributions from urban and regional background concentrations given the highly variable and complex emissions and dispersion characteristics. In this study, we used continuous mobile monitoring of traffic-related particulate air pollutants to assess the contribution to concentrations, above background, of traffic in the street canyons of midtown Manhattan. Concentrations of both ultrafine particles (UFP) and fine particles (PM 2.5) were measured at street level using portable instruments. Statistical modeling techniques accounting for autocorrelation were used to investigate the presence of spatial heterogeneity of pollutant concentrations as well as to quantify the contribution of within-canyon traffic sources. Measurements were also made within Central Park, to examine the impact of offsets from major roadways in this urban environment. On average, an approximate 11% increase in concentrations of UFP and 8% increase in concentrations of PM 2.5 over urban background was estimated during high-traffic periods in street canyons as opposed to low traffic periods. Estimates were 8% and 5%, respectively, after accounting for temporal autocorrelation. Within Central Park, concentrations were 40% higher than background (5% after accounting for temporal autocorrelation) within the first 100 m from the nearest roadway for UFP, with a smaller but statistically significant increase for PM 2.5. Our findings demonstrate the viability of a mobile monitoring protocol coupled with spatiotemporal modeling techniques in characterizing local source contributions in a setting with street canyons.

  6. Characterization of water movement in a reconstructed slope in Keokuk, Iowa, using advanced geophysical techniques

    NASA Astrophysics Data System (ADS)

    Schettler, Megan Elizabeth

    This project addresses the topic of evaluating water movement inside a hillslope using a combination of conventional and advanced geophysical techniques. While slope dynamics have been widely studied, ground water movement in hills is still poorly understood. A combination of piezometers, ground-penetrating radar (GPR), and electrical resistivity (ER) surveys were used in an effort to monitor fluctuations in the subsurface water level in a reengineered slope near Keokuk, Iowa. This information, integrated with rainfall data, formed a picture of rainfall-groundwater response dynamics. There were two hypotheses: 1) that the depth and fluctuation of the water table could be accurately sensed using a combination of monitoring wells, ground-penetrating radar and resistivity surveys; and 2) that the integration of data from the instrumentation array and the geophysical surveys would enable the characterization of water movement in the slope in response to rainfall events. This project also sought to evaluate the utility and limitations of using these techniques in landslide and hydrology studies, advance our understanding of hillslope hydrology, and improve our capacity to better determine when slope failure may occur. Results from monitoring wells, stratigraphy, and resistivity surveys at the study site indicated the presence of a buried swale, channelizing subsurface storm flow and creating variations in groundwater. Although there was some success in defining hydrologic characteristics and response of the slope using this integrated approach, it was determined that GPR was ultimately not well suited to this site. However, the use of GPR as part of an integrated approach to study hillslope hydrology still appears to hold potential, and future work to further evaluate the applicability and potential of this approach would be warranted.

  7. Characterization of Porosity Development in Oxidized Graphite using Automated Image Analysis Techniques

    SciTech Connect

    Contescu, Cristian I; Burchell, Timothy D

    2009-09-01

    This document reports on initial activities at ORNL aimed at quantitative characterization of porosity development in oxidized graphite specimens using automated image analysis (AIA) techniques. A series of cylindrical shape specimens were machined from nuclear-grade graphite (type PCEA, from GrafTech International). The specimens were oxidized in air to various levels of weight loss (between 5 and 20 %) and at three oxidation temperatures (between 600 and 750 oC). The procedure used for specimen preparation and oxidation was based on ASTM D-7542-09. Oxidized specimens were sectioned, resin-mounted and polished for optical microscopy examination. Mosaic pictures of rectangular stripes (25 mm x 0.4 mm) along a diameter of sectioned specimens were recorded. A commercial software (ImagePro) was evaluated for automated analysis of images. Because oxidized zones in graphite are less reflective in visible light than the pristine, unoxidized material, the microstructural changes induced by oxidation can easily be identified and analyzed. Oxidation at low temperatures contributes to development of numerous fine pores (< 100 m2) distributed more or less uniformly over a certain depth (5-6 mm) from the surface of graphite specimens, while causing no apparent external damage to the specimens. In contrast, oxidation at high temperatures causes dimensional changes and substantial surface damage within a narrow band (< 1 mm) near the exposed graphite surface, but leaves the interior of specimens with little or no changes in the pore structure. Based on these results it appears that weakening and degradation of mechanical properties of graphite materials produced by uniform oxidation at low temperatures is related to the massive development of fine pores in the oxidized zone. It was demonstrated that optical microscopy enhanced by AIA techniques allows accurate determination of oxidant penetration depth and of distribution of porosity in oxidized graphite materials.

  8. Routine characterization of 3-D profiles of SRF cavity defects using replica techniques

    SciTech Connect

    Ge, M.; Wu, G.; Burk, D.; Ozelis, J.; Harms, E.; Sergatskov, D.; Hicks, D.; Cooley, L.D.; /Fermilab

    2010-09-01

    Recent coordination of thermometry with optical images has shown that obvious defects at specific locations produce heat or even quench superconducting radio frequency (SRF) cavities, imposing a significant limit on the overall accelerating gradient produced by the cavity. Characterization of the topography at such locations provides clues about how the defects originated, from which schemes for their prevention might be devised. Topographic analyses also provide understanding of the electromagnetic mechanism by which defects limit cavity performance, from which viability of repair techniques might be assessed. In this article we discuss how a variety of two-component silicone-based room-temperature vulcanizing agents can be routinely used to make replicas of the cavity surface and extract topographic details of cavity defects. Previously, this level of detail could only be obtained by cutting suspect regions from the cavity, thus destroying the cavity. We show 3-D profiles extracted from several different 1.3 GHz cavities. The defect locations, which were all near cavity welds, compelled us to develop extraction techniques for both equator and iris welds as well as from deep inside long 9-cell cavities. Profilometry scans of the replicas yield micrometer-scale information, and we describe various curious features, such as small peaks at the bottom of pits, which were not apparent in previous optical inspections. We also discuss contour information in terms of electromagnetic mechanisms proposed by others for local cavity heating. We show that production of the replica followed by high-pressure rinsing dose not adversely affect the cavity RF performance.

  9. Magnetization studies of embedded and coated thin films using Magneto-Optic Kerr Effect

    NASA Astrophysics Data System (ADS)

    Balasubramanian, Srinath

    The advancements made in electronic storage demand characterization of new materials and magnetic structures. The Magneto-Optic Kerr Effect (MOKE) is an interesting tool to characterize materials for usage in modern electronic storage devices such as magneto-optical drive, magnetic random access memory and spin valve devices. In this work, an attempt was made to characterize embedded and coated films using Magneto-Optic Kerr Effect technique. An experimental system was built for the measurement of Kerr rotation. Magnetization studies of PMMA (Poly(methyl methacrylate)) films embedded with iron nanoparticles and quartz films coated with hematite nanoparticles were carried out using MOKE. The embedded films exhibited weak magnetic response. For the coated films, the hysteresis loops were shifted from the origin indicating the presence of exchange bias in the system. Symmetric and asymmetric magnetization reversals were observed due to the presence of antiferromagnetic regions non-collinear with the external magnetic field. The samples with higher concentrations of nanoparticles showed dipolar interactions at relatively low fields. The coated films showed better magneto-optic response as compared to the embedded films. The exchange bias effects in the coated films makes it a candidate for various applications such as permanent magnets, magnetic recording media and stabilizers in recording heads.

  10. Novel Techniques for Optical Characterization of Single-Walled Carbon Nanotube Samples

    NASA Astrophysics Data System (ADS)

    Streit, Jason K.

    Photoluminescence spectroscopy has emerged as a powerful tool for characterizing the structure and optical properties of single-walled carbon nanotube (SWCNT) samples. This thesis will discuss the development and application of new fluorescence-based methods designed to fully characterize bulk SWCNT suspensions by length and structural composition. An efficient new method is demonstrated to measure length distributions of aqueous SWCNT samples by analyzing the diffusional motions of many individual nanotubes captured in sequences of short-wave infrared (SWIR) fluorescence images. This method, termed length analysis by nanotube diffusion (LAND), provides distributions in very good agreement with those obtained by conventional atomic force microscopy analysis. A novel microscopy technique is described to measure the peak emission wavelengths of many individual nanotubes without the use of a spectrometer. We exploit the chromatic aberration of an objective lens to deduce emission wavelength from focal depth. Spectral measurements successfully reproduce bulk emission spectra and also provide relative abundances of specific SWCNT structures. A new approach is applied to find nanotube concentrations by directly counting SWCNTs in SWIR fluorescence images. Concentrations are used to rigorously determine absolute absorption cross sections for the E11 and E22 electronic transitions of the (6,5), (7,5), (7,6), (8,6), (8,7) and (9,7) SWCNT species. It is found that the absorption cross section per carbon atom decreases with increasing nanotube diameter. Finally, the spectral analysis of fluorescence fluctuations (SAFF) method is developed and used to characterize SWCNT samples by structural composition, sample quality, and aggregation state. Fluorescence spectra are sequentially measured from small volumes of slowly flowing dilute samples and the intensity fluctuations resulting from small statistical variations in nanotube concentration are analyzed. The ratio of the squared

  11. Novel techniques for characterization of hydrocarbon emission sources in the Barnett Shale

    NASA Astrophysics Data System (ADS)

    Nathan, Brian Joseph

    Changes in ambient atmospheric hydrocarbon concentrations can have both short-term and long-term effects on the atmosphere and on human health. Thus, accurate characterization of emissions sources is critically important. The recent boom in shale gas production has led to an increase in hydrocarbon emissions from associated processes, though the exact extent is uncertain. As an original quantification technique, a model airplane equipped with a specially-designed, open-path methane sensor was flown multiple times over a natural gas compressor station in the Barnett Shale in October 2013. A linear optimization was introduced to a standard Gaussian plume model in an effort to determine the most probable emission rate coming from the station. This is shown to be a suitable approach given an ideal source with a single, central plume. Separately, an analysis was performed to characterize the nonmethane hydrocarbons in the Barnett during the same period. Starting with ambient hourly concentration measurements of forty-six hydrocarbon species, Lagrangian air parcel trajectories were implemented in a meteorological model to extend the resolution of these measurements and achieve domain-fillings of the region for the period of interest. A self-organizing map (a type of unsupervised classification) was then utilized to reduce the dimensionality of the total multivariate set of grids into characteristic one-dimensional signatures. By also introducing a self-organizing map classification of the contemporary wind measurements, the spatial hydrocarbon characterizations are analyzed for periods with similar wind conditions. The accuracy of the classification is verified through assessment of observed spatial mixing ratio enhancements of key species, through site-comparisons with a related long-term study, and through a random forest analysis (an ensemble learning method of supervised classification) to determine the most important species for defining key classes. The hydrocarbon

  12. Characterization of a Novel Anti-Human HB-EGF Monoclonal Antibody Applicable for Paraffin-Embedded Tissues and Diagnosis of HB-EGF-Related Cancers

    PubMed Central

    Iwamoto, Ryo; Takagi, Mika; Akatsuka, Jun-ichi; Ono, Ken-ichiro; Kishi, Yoshiro

    2016-01-01

    Heparin-binding EGF-like growth factor (HB-EGF) is a member of the EGF family of growth factors that bind to and activate the EGF receptor (EGFR/ErbB1) and ErbB4. HB-EGF plays pivotal roles in pathophysiological processes, including cancer. Thus, monoclonal antibodies (mAbs) for HB-EGF detection could be an important tool in the therapeutic diagnosis of HB-EGF-related cancers and other diseases. However, few mAbs, especially those applicable for immunohistochemistry (IHC), have been established to date. In this study, we generated a clone of hybridoma-derived mAb 2-108 by immunizing mice with recombinant human HB-EGF protein expressed by human cells. The mAb 2-108 specifically bound to human HB-EGF but not to mouse HB-EGF and was successful in immunoblotting, even under reducing conditions, immunoprecipitation, and immunofluorescence for unfixed as well as paraformaldehyde-fixed cells. Notably, this mAb was effective in IHC of paraffin-embedded tumor specimens. Epitope mapping analysis showed that mAb 2-108 recognized the N-terminal prodomain in HB-EGF. These results indicate that this new anti-HB-EGF mAb 2-108 would be useful in the diagnosis of HB-EGF-related cancers and would be a strong tool in both basic and clinical research on HB-EGF. PMID:26974561

  13. Production of luster glaze on opal tableware using zarinfam technique and characterization of its structure and color

    NASA Astrophysics Data System (ADS)

    Razavi, Fahime; Rashidi Huyeh, Majid; Ghahari, Mahdi

    2016-05-01

    Lusters are potters that have attracted much attention due to their specific optical features, one of the most important of which is their sparkle that appears in various colors at different angles. This effect linked to the multilayer structure of luster and the presence of metallic nanoparticles in enamel layer. In this research, luster glaze was produced on Opal tableware, manufactured in Mahfam Jam Co., using Zarinfam technique. SEM micrograph image of the samples indicated that the glaze forms a multilayer structure, on the Opal tableware surface, consisting of a glassy superficial layer of some tens of nanometers and a composite layer of some hundreds of nanometers. The enamel composite layer contains silver nanoparticles embedded in a silica medium. Employing a multilayer model, we studied the influence of different parameters such as luster enamel thickness, nanoparticles volume fraction in enamel, nanoparticle size, observe angle, and glass layer thickness on luster color.

  14. Phase topography-based characterization of thermal effects on materials and joining techniques.

    PubMed

    Lorenz, Hagen; Beckert, Erik; Schödel, René

    2015-03-10

    There are growing demands to characterize the stability of assemblies of optical components for ultrahigh-precision instruments. In this paper we demonstrate how absolute length measurements by interferometry can be applied to measure the thermal and dimensional stability of connections. In order to enable investigation of common joining techniques, including wringing, screwing, and gluing, as well as specialized, inorganic joining techniques such as silicatic bonding, thin-film soldering, and solderjet bumping, representative connections were fabricated. By using gage blocks or prismatic bodies as joining parts, parallelism and flatness were provided which are needed for precision interferometric length measurements. The stability of connection elements used in ultrahigh-precision instruments was investigated longitudinally and laterally to the connection interface, and also mutual tilting of the parts was detected by analysis of the phase topographies. The measurements have an accuracy level of about 1 nm, and the traditional wringing method was also considered as a reference joining technique. The long-term behavior was studied within a period of about 1 year under constant temperature. Further, the thermal dilatation and the reaction of connections to thermal stress were measured. Results show that screwed connections do not exhibit a significant drift of length or orientation. They also did not show response to temperature variations of ±10°C. This is different for adhesive connections, where dimensional changes of up to 100 nm were observed. The specimens produced by using thin-film soldering as well as silicatic bonding revealed stability of length better than 5 nm per year and angular stability within ±0.1   arcsec. Furthermore, these specimens were shown to be insensitive to a temporary temperature variation in a range from 10°C to 40°C. This situation is slightly different for the sample connections produced by solderjet bumping, which show a

  15. Nondestructive characterization of thermal barrier coating by noncontact laser ultrasonic technique

    NASA Astrophysics Data System (ADS)

    Zhao, Yang; Chen, Jianwei; Zhang, Zhenzhen

    2015-09-01

    We present the application of a laser ultrasonic technique in nondestructive characterization of the bonding layer (BL) in a thermal barrier coating (TBC). A physical mode of a multilayered medium is established to describe the propagation of a longitudinal wave generated by a laser in a TBC system. Furthermore, the theoretical analysis on the ultrasonic transmission in TBC is carried out in order to derive the expression of the BL transmission coefficient spectrum (TCS) which is used to determine the velocity of the longitudinal wave in the BL. We employ the inversion method combined with TCS to ascertain the attenuation coefficient of the BL. The experimental validations are performed with TBC specimens produced by an electron-beam physical vapor deposition method. In those experiments, a pulsed laser with a width of 10 ns is used to generate an ultrasonic signal while a two-wave mixing interferometer is created to receive the ultrasonic signals. By introducing the wavelet soft-threshold method that improves the signal-to-noise ratio, the laser ultrasonic testing results of TBC with an oxidation of 1 cycle, 10 cycles, and 100 cycles show that the attenuation coefficients of the BL become larger with an increase in the oxidation time, which is evident for the scanning electron microscopy observations, in which the thickness of the thermally grown oxide increases with oxidation time.

  16. Multi-technique characterization of poly-L-lysine dendrigrafts-Cu(II) complexes for biocatalysis.

    PubMed

    Rossi, Jean-Christophe; Maret, Barbara; Vidot, Kevin; Francoia, Jean-Patrick; Cangiotti, Michela; Lucchi, Susanna; Coppola, Concetta; Ottaviani, Maria Francesca

    2015-02-01

    Poly-L-lysine is a biocompatible polymer used for drug or gene delivery, for transport through cellular membranes, and as nanosized magnetic resonance imaging contrast agents. Cu(II)-poly-L-lysine complexes are of particular interest for their role in biocatalysis. In this study, poly-L-lysine dendrigrafts (DGLs) at different generations (G2, G3, and G4) are synthesized and characterized in absence and presence of Cu(II) by means of electron paramagnetic resonance (EPR), UV-Vis, potentiometric titration and circular dichroism (CD). The analysis is performed as a function of the [Cu(II)]/[Lys] (=R) molar ratio, pH and generation by identifying differently flexible complexes in different dendrimer regions. The amine sites in the lateral chains become increasingly involved with the increase of pH. The good agreement and complementarity of the results from the different techniques provide an integrate view of the structural and dynamic properties of Cu(II)-DGL complexes implementing their use as biocatalysts. PMID:25330467

  17. Immunological techniques as tools to characterize the subsurface microbial community at a trichloroethylene contaminated site

    SciTech Connect

    Fliermans, C.B.; Dougherty, J.M.; Franck, M.M.; McKinzey, P.C.; Hazen, T.C.

    1992-12-31

    Effective in situ bioremediation strategies require an understanding of the effects pollutants and remediation techniques have on subsurface microbial communities. Therefore, detailed characterization of a site`s microbial communities is important. Subsurface sediment borings and water samples were collected from a trichloroethylene (TCE) contaminated site, before and after horizontal well in situ air stripping and bioventing, as well as during methane injection for stimulation of methane-utilizing microorganisms. Subsamples were processed for heterotrophic plate counts, acridine orange direct counts (AODC), community diversity, direct fluorescent antibodies (DFA) enumeration for several nitrogen-transforming bacteria, and Biolog {reg_sign} evaluation of enzyme activity in collected water samples. Plate counts were higher in near-surface depths than in the vadose zone sediment samples. During the in situ air stripping and bioventing, counts increased at or near the saturated zone, remained elevated throughout the aquifer, but did not change significantly after the air stripping. Sporadic increases in plate counts at different depths as well as increased diversity appeared to be linked to differing lithologies. AODCs were orders of magnitude higher than plate counts and remained relatively constant with depth except for slight increases near the surface depths and the capillary fringe. Nitrogen-transforming bacteria, as measured by serospecific DFA, were greatly affected both by the in situ air stripping and the methane injection. Biolog{reg_sign} activity appeared to increase with subsurface stimulation both by air and methane. The complexity of subsurface systems makes the use of selective monitoring tools imperative.

  18. Immunological techniques as tools to characterize the subsurface microbial community at a trichloroethylene contaminated site

    SciTech Connect

    Fliermans, C.B.; Dougherty, J.M.; Franck, M.M.; McKinzey, P.C.; Hazen, T.C.

    1992-01-01

    Effective in situ bioremediation strategies require an understanding of the effects pollutants and remediation techniques have on subsurface microbial communities. Therefore, detailed characterization of a site's microbial communities is important. Subsurface sediment borings and water samples were collected from a trichloroethylene (TCE) contaminated site, before and after horizontal well in situ air stripping and bioventing, as well as during methane injection for stimulation of methane-utilizing microorganisms. Subsamples were processed for heterotrophic plate counts, acridine orange direct counts (AODC), community diversity, direct fluorescent antibodies (DFA) enumeration for several nitrogen-transforming bacteria, and Biolog [reg sign] evaluation of enzyme activity in collected water samples. Plate counts were higher in near-surface depths than in the vadose zone sediment samples. During the in situ air stripping and bioventing, counts increased at or near the saturated zone, remained elevated throughout the aquifer, but did not change significantly after the air stripping. Sporadic increases in plate counts at different depths as well as increased diversity appeared to be linked to differing lithologies. AODCs were orders of magnitude higher than plate counts and remained relatively constant with depth except for slight increases near the surface depths and the capillary fringe. Nitrogen-transforming bacteria, as measured by serospecific DFA, were greatly affected both by the in situ air stripping and the methane injection. Biolog[reg sign] activity appeared to increase with subsurface stimulation both by air and methane. The complexity of subsurface systems makes the use of selective monitoring tools imperative.

  19. Collection and characterization of aerosols from metal cutting techniques typically used in decommissioning nuclear facilities.

    PubMed

    Newton, G J; Hoover, M D; Barr, E B; Wong, B A; Ritter, P D

    1987-11-01

    This study was designed to collect and characterize aerosols released during metal cutting activities typically used in decommissioning radioactively contaminated facilities. Such information can guide in the selection of appropriate control technologies for these airborne materials. Mechanical cutting tools evaluated included a multi-wheel pipe cutter, reciprocating saw, band saw, chop saw, and large and small grinding wheels. Melting-vaporization cutting techniques included an oxy-acetylene torch, electric arc cut rod and plasma torch. With the exception of the multi-wheel pipe cutter, all devices created aerosols in the respirable size range (less than 10 micron aerodynamic diameter). Time required to cut 2-in. (5-cm) Schedule 40, Type 304L, stainless steel ranged from about 0.6 min for the plasma torch to about 3.0 min for the reciprocating saw. Aerosol production rate ranged from less than 10 mg/min for the reciprocating saw to more than 3000 mg/min for the electric arc cut rod. Particles from mechanical tools were irregular in shape, whereas particles from vaporization tools were spheres and ultrafine branched-chain aggregates. PMID:3425551

  20. The use of laser-induced plasma spectroscopy technique for the characterization of boiler tubes

    NASA Astrophysics Data System (ADS)

    Nicolas, G.; Mateo, M. P.; Yañez, A.

    2007-12-01

    The present work focuses on the characterization of boiler tube walls using laser-induced plasma spectroscopy technique with visual inspection by optical and scanning electron microscopy of the cross-sections of these tubes. In a watertube boiler, water runs through tubes that are surrounded by a heating source. As a result, the water is heated to very high temperatures, causing accumulation of deposits on the inside surfaces of the tubes. These deposits play an important role in the efficiency of the boiler tube because they produce a reduction of the boiler heat rate and an increase in the number of tube failures. The objectives are to determine the thickness and arrangement of deposits located on the highest heat area of the boiler and compare them with tube parts where the heat flux is lower. The major deposits found were copper and magnetite. These deposits come mainly from the boiler feedwater and from the reaction between iron and water, and they do not form on the tube walls at a uniform rate over time. Their amount depends on the areas where they are collected. A Nd:YAG laser operating at 355 nm has been used to perform laser-induced plasma spectra and depth profiles of the deposits.

  1. Characterization and analysis of surface notches on Ti-alloy plates fabricated by additive manufacturing techniques

    NASA Astrophysics Data System (ADS)

    Chan, Kwai S.

    2015-12-01

    Rectangular plates of Ti-6Al-4V with extra low interstitial (ELI) were fabricated by layer-by-layer deposition techniques that included electron beam melting (EBM) and laser beam melting (LBM). The surface conditions of these plates were characterized using x-ray micro-computed tomography. The depth and radius of surface notch-like features on the LBM and EBM plates were measured from sectional images of individual virtual slices of the rectangular plates. The stress concentration factors of individual surface notches were computed and analyzed statistically to determine the appropriate distributions for the notch depth, notch radius, and stress concentration factor. These results were correlated with the fatigue life of the Ti-6Al-4V ELI alloys from an earlier investigation. A surface notch analysis was performed to assess the debit in the fatigue strength due to the surface notches. The assessment revealed that the fatigue lives of the additively manufactured plates with rough surface topographies and notch-like features are dominated by the fatigue crack growth of large cracks for both the LBM and EBM materials. The fatigue strength reduction due to the surface notches can be as large as 60%-75%. It is concluded that for better fatigue performance, the surface notches on EBM and LBM materials need to be removed by machining and the surface roughness be improved to a surface finish of about 1 μm.

  2. Synthesis and Characterization of Cholesterol Nano Particles by Using w/o Microemulsion Technique

    NASA Astrophysics Data System (ADS)

    Vyas, Poorvesh M.; Vasant, Sonal R.; Hajiyani, Rakesh R.; Joshi, Mihir J.

    2010-10-01

    Cholesterol is one of the most abundant and well known steroids in the animal kingdom. Cholesterol rich micro-emulsions and nano-emulsions are useful for the treatment of breast cancer and gynecologic cancers. The nano particles of cholesterol and other pharmaceutically important materials have been reported. In the present investigation, the nano particles of cholesterol were synthesized by direct precipitation technique using triton X-100/water/n-butanol micro-emulsion. The average particle size of cholesterol nano particles was estimated by applying Scherrer's formula to the powder X-ray diffraction pattern, which was found to be 22 nm. The nanoparticles of cholesterol were observed by using TEM and the particle size was found within the range from 15 nm-31 nm. The distribution of particle size was studied through DLS. The nanoparticles of cholesterol were characterized by using FT-IR spectroscopy and the force constant was also calculated for O-H, C-H and C-O bonds. The thermal response of nanoparticles of cholesterol was studied by TGA, which showed that the nanoparticles were stable up to 200 °C and then decomposed. Kinetic and thermodynamic parameters of decomposition process were also calculated by applying Coats and Redfern formula to thermo-gram.

  3. Characterization of Carbon Dioxide Washout Measurement Techniques in the Mark-III Space Suit

    NASA Technical Reports Server (NTRS)

    Bekdash, O.; Norcross, J.; Meginnis, I.

    2016-01-01

    Providing adequate carbon dioxide (CO2) washout is essential to the reduction of risk in performing suited operations. Long term CO2 exposure can lead to symptoms such as headache, lethargy, and dizziness. Thus maintaining adequate CO2 washout in both ground testing and during in flight EVAs is a requirement of current and future suit designs. It is necessary to understand the inspired CO2 of suit wearers such that future requirements for space suits appropriately address the risk of inadequate washout. Testing conducted by the EVA Physiology Laboratory at the NASA Johnson Space Center aimed to characterize a method for noninvasively measuring inspired oronasal CO2 under pressurized suited conditions in order to better inform requirements definition and verification techniques for future CO2 washout limits in space suits. Based on a meta-analysis of those studies it was decided to test a nasal cannula as it is a commercially available device, would not impede suit ventilation delivery, and is placed directly in the breathing path of the user.

  4. Collection and characterization of aerosols from metal cutting techniques typically used in decommissioning nuclear facilities

    SciTech Connect

    Newton, G.J.; Hoover, M.D.; Barr, E.B.; Wong, B.A.; Ritter, P.D.

    1987-11-01

    This study was designed to collect and characterize aerosols released during metal cutting activities typically used in decommissioning radioactively contaminated facilities. Such information can guide in the selection of appropriate control technologies for these airborne materials. Mechanical cutting tools evaluated included a multi-wheel pipe cutter, reciprocating saw, band saw, chop saw, and large and small grinding wheels. Melting-vaporization cutting techniques included an oxy-acetylene torch, electric arc cut rod and plasma torch. With the exception of the multi-wheel pipe cutter, all devices created aerosols in the respirable size range (less than 10 micron aerodynamic diameter). Time required to cut 2-in. (5-cm) Schedule 40, Type 304L, stainless steel ranged from about 0.6 min for the plasma torch to about 3.0 min for the reciprocating saw. Aerosol production rate ranged from less than 10 mg/min for the reciprocating saw to more than 3000 mg/min for the electric arc cut rod. Particles from mechanical tools were irregular in shape, whereas particles from vaporization tools were spheres and ultrafine branched-chain aggregates.

  5. Generalized 1D photopyroelectric technique for optical and thermal characterization of liquids

    NASA Astrophysics Data System (ADS)

    Balderas-López, J. A.

    2012-06-01

    The analytical solution for the one-dimensional heat diffusion problem for a three-layer system, in the Beer-Lambert model for light absorption, is used for the implementation of a photopyroelectric (PPE) methodology for thermal and optical characterization of pigments in liquid solution, even for those ones potentially harmful to the pyroelectric sensor, taking the liquid sample's thickness as the only variable. Exponential decay of the PPE amplitude followed by a constant PPE phase for solutions at low pigment concentration, and exponential decay of the PPE amplitude but a linear decrease of the PPE phase for the concentrated ones are theoretically shown, allowing measurements of the optical absorption coefficient (at the wavelength used for the analysis) and the thermal diffusivity for the liquid sample, respectively. This PPE methodology was tested by measuring the thermal diffusivity of a concentrated solution of methylene blue in distilled water and the optical absorption coefficient, at two wavelengths (658 and 785 nm), of water solutions of copper sulfate at various concentrations. These optical parameters were used for measuring the molar absorption coefficient of this last pigment in water solution at these two wavelengths. This last optical property was also measured using a commercial spectrometer, finding very good agreement with the corresponding ones using this PPE technique.

  6. Characterization of Air Plane Soot Surrogates using Raman spectroscopy and laser ablation techniques

    NASA Astrophysics Data System (ADS)

    Chazallon, Bertrand; Ortega, Ismael Kenneth; Ikhenazene, Raouf; Pirim, Claire; Carpentier, Yvain; Irimiea, Cornelia; Focsa, Cristian; Ouf, François-Xavier

    2016-04-01

    Aviation alters the composition of the atmosphere globally and can thus drive climate change and ozone depletion [1]. Aircraft exhaust plumes contain species (gases and soot particles) produced by the combustion of kerosene with ambient air in the combustion chamber of the engine. Soot particles emitted by air-planes produce persistent contrails in the upper troposphere in ice-supersaturated air masses that contribute to cloudiness and impact the radiative properties of the atmosphere. These aerosol-cloud interactions represent one of the largest sources of uncertainty in global climate models [2]. Though the formation of atmospheric ice particles has been studied for many years [3], there are still numerous opened questions on nucleation properties of soot particles [4], as the ice nucleation experiments showed a large spread in results depending on the nucleation mode chosen and origin of the soot produced. The reasons behind these discrepancies reside in the different physico-chemical properties (composition, structure) of soot particles produced in different conditions, e.g., with respect to fuel or combustion techniques. In this work, we use Raman microscopy (514 and 785 nm excitation wavelengths) and ablation techniques (Secondary Ions Mass Spectrometry, and Laser Desorption Mass Spectrometry) to characterize soot particle surrogates produced from a CAST generator (propane fuel, four different global equivalence ratios). They are produced as analogues of air-plane soot collected at different engine regimes (PowerJet SaM-146 turbofan) simulating a landing and take-off (LTO) cycle (MERMOSE project (http://mermose.onera.fr/)) [6]. The spectral parameters of the first-order Raman bands of these soot samples are analyzed using a de-convolution approach described by Sadezky et al. (2005) [5]. A systematic Raman analysis is carried out to select a number of parameters (laser wavelength, irradiance at sample, exposure time) that will alter the sample and the

  7. A unified data embedding and scrambling method.

    PubMed

    Rad, Reza Moradi; Wong, Koksheik; Guo, Jing-Ming

    2014-04-01

    Conventionally, data embedding techniques aim at maintaining high-output image quality so that the difference between the original and the embedded images is imperceptible to the naked eye. Recently, as a new trend, some researchers exploited reversible data embedding techniques to deliberately degrade image quality to a desirable level of distortion. In this paper, a unified data embedding-scrambling technique called UES is proposed to achieve two objectives simultaneously, namely, high payload and adaptive scalable quality degradation. First, a pixel intensity value prediction method called checkerboard-based prediction is proposed to accurately predict 75% of the pixels in the image based on the information obtained from 25% of the image. Then, the locations of the predicted pixels are vacated to embed information while degrading the image quality. Given a desirable quality (quantified in SSIM) for the output image, UES guides the embedding-scrambling algorithm to handle the exact number of pixels, i.e., the perceptual quality of the embedded-scrambled image can be controlled. In addition, the prediction errors are stored at a predetermined precision using the structure side information to perfectly reconstruct or approximate the original image. In particular, given a desirable SSIM value, the precision of the stored prediction errors can be adjusted to control the perceptual quality of the reconstructed image. Experimental results confirmed that UES is able to perfectly reconstruct or approximate the original image with SSIM value > 0.99 after completely degrading its perceptual quality while embedding at 7.001 bpp on average. PMID:24565789

  8. Development of ICP-MS based nanometrology techniques for characterization of silver nanoparticles in environmental systems

    NASA Astrophysics Data System (ADS)

    Mitrano, Denise Marie

    The ubiquitous use of goods containing nanoparticles (NPs) will lead inevitably to environmental release and interaction with biota. Methods to detect, quantify, and characterize NPs in environmental matrices are highlighted as one of the areas of highest priority research in understanding potential environmental and health risks. Specifically, techniques are needed to determine the size and concentration of NPs in complex matrices. Particular analytical challenges include distinguishing NPs from other constituents of the matrix (i.e. natural particles, humic substances, and debris), method detection limits are often higher than exposure concentrations, and differentiating dissolved metal and NPs. This work focuses on the development and optimization of two methods that address a number of challenges for nanometrology: single particle (sp)ICP-MS and asymmetrical flow field flow fractionation (AF4)-ICP-MS. Advancements in the spICP-MS method included systematic studies on distinction between ionic and NP fractions, resolution of polydisperse NP samples, and defining the techniques' dynamic range (in terms of both particle size and concentration). Upon application of the technique, silver (Ag) NPs were discovered in raw wastewater treatment plant influent and effluent. Furthermore, methodical Ag NP stability studies determined the influence of particle capping agents and water chemistry parameters in a variety of synthetic, natural and processed waters. Method development for AF4-ICP-MS revolved around optimizing run conditions (i.e. operational flows, carrier fluid, membrane choice) to study detection limits, sample recovery, and resolution of polydisperse samples. Practical studies included sizing Ag NP in a sediment-dwelling, freshwater oligochaete (Lumbriculus variegatus) and the kinetics of accumulation of protein bound Ag+. In direct comparison, spICP-MS was found to be more versatile with less sample preparation and lower total analyte detection limit (ng/L vs

  9. Materials and characterization techniques for high-temperature polymer electrolyte membrane fuel cells

    PubMed Central

    2015-01-01

    Summary The performance of high-temperature polymer electrolyte membrane fuel cells (HT-PEMFC) is critically dependent on the selection of materials and optimization of individual components. A conventional high-temperature membrane electrode assembly (HT-MEA) primarily consists of a polybenzimidazole (PBI)-type membrane containing phosphoric acid and two gas diffusion electrodes (GDE), the anode and the cathode, attached to the two surfaces of the membrane. This review article provides a survey on the materials implemented in state-of-the-art HT-MEAs. These materials must meet extremely demanding requirements because of the severe operating conditions of HT-PEMFCs. They need to be electrochemically and thermally stable in highly acidic environment. The polymer membranes should exhibit high proton conductivity in low-hydration and even anhydrous states. Of special concern for phosphoric-acid-doped PBI-type membranes is the acid loss and management during operation. The slow oxygen reduction reaction in HT-PEMFCs remains a challenge. Phosphoric acid tends to adsorb onto the surface of the platinum catalyst and therefore hampers the reaction kinetics. Additionally, the binder material plays a key role in regulating the hydrophobicity and hydrophilicity of the catalyst layer. Subsequently, the binder controls the electrode–membrane interface that establishes the triple phase boundary between proton conductive electrolyte, electron conductive catalyst, and reactant gases. Moreover, the elevated operating temperatures promote carbon corrosion and therefore degrade the integrity of the catalyst support. These are only some examples how materials properties affect the stability and performance of HT-PEMFCs. For this reason, materials characterization techniques for HT-PEMFCs, either in situ or ex situ, are highly beneficial. Significant progress has recently been made in this field, which enables us to gain a better understanding of underlying processes occurring during

  10. Nickel nanoparticles embedded in carbon foam for improving electromagnetic shielding effectiveness

    NASA Astrophysics Data System (ADS)

    Kumar, Rajeev; Kumari, Saroj; Dhakate, Sanjay R.

    2014-08-01

    To improve electromagnetic shielding effectiveness of light weight carbon foam (CF), magnetic nanoparticles were embedded in it during processing. The CF was developed from the coal tar pitch and mixture of coal tar pitch-Nickel (Ni) nanoparticles by sacrificial template technique and heat treated to up 1,000 °C. To ascertain the effect of Ni nanoparticles embedded in CF, it was characterized by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, vector network analyzer and vibration sample magnetometer. It is observed that Ni nanoparticles embedded in the carbon material play an important role for improving the structure and electrical conductivity of CF-Ni by catalytic carbonization. The structural investigation suggests that the Ni nanoparticles embedded in the carbon material in bulk as well on the surface of CF. The CF demonstrates excellent shielding response in the frequency range 8.2-12.4 GHz in which total shielding effectiveness (SE) dominated by absorption losses. The total SE is -25 and -61 dB of CF and CF-Ni, it is governed by absorption losses -48.5 dB in CF-Ni. This increase is due to the increase in dielectric and magnetic losses of ferromagnetic Ni nanoparticles with high surface area. Thus, light weight CF embedded with small amount of magnetic nanoparticles can be useful material for stealth technology.

  11. Nickel nanoparticles embedded in carbon foam for improving electromagnetic shielding effectiveness

    NASA Astrophysics Data System (ADS)

    Kumar, Rajeev; Kumari, Saroj; Dhakate, Sanjay R.

    2015-06-01

    To improve electromagnetic shielding effectiveness of light weight carbon foam (CF), magnetic nanoparticles were embedded in it during processing. The CF was developed from the coal tar pitch and mixture of coal tar pitch-Nickel (Ni) nanoparticles by sacrificial template technique and heat treated to up 1,000 °C. To ascertain the effect of Ni nanoparticles embedded in CF, it was characterized by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, vector network analyzer and vibration sample magnetometer. It is observed that Ni nanoparticles embedded in the carbon material play an important role for improving the structure and electrical conductivity of CF-Ni by catalytic carbonization. The structural investigation suggests that the Ni nanoparticles embedded in the carbon material in bulk as well on the surface of CF. The CF demonstrates excellent shielding response in the frequency range 8.2-12.4 GHz in which total shielding effectiveness (SE) dominated by absorption losses. The total SE is -25 and -61 dB of CF and CF-Ni, it is governed by absorption losses -48.5 dB in CF-Ni. This increase is due to the increase in dielectric and magnetic losses of ferromagnetic Ni nanoparticles with high surface area. Thus, light weight CF embedded with small amount of magnetic nanoparticles can be useful material for stealth technology.

  12. Characterization of Mineral Assemblages in Ancient Roman Maritime Concrete with Synchrotron X-ray Techniques

    NASA Astrophysics Data System (ADS)

    Meral, C.; Jackson, M. D.; Monteiro, P. J.; Wenk, H.

    2012-12-01

    Romans used lime and aluminosilicate-rich volcanic ash to bind tuff aggregates in concrete structures that have remained durable for 2000 years. A major accomplishment of Roman engineers was to construct enduring coastal underwater structures in seawater, which were important to long-distance trade and military endeavors. Two millennia later, the reasons for the extraordinary durability of the maritime structures remain enigmatic. The concretes are highly complex composites composed of relict lime, tuff and pumice clasts and pozzolanic reaction products. Calcium-chloroaluminates and sulfoaluminates occur in certain relict voids. Further understanding of their mineralogical components would provide guidelines in designing future structures. Here, we use synchroton radiation applications to characterize certain phases within a Roman maritime mortar specimen from a breakwater in Pozzuoli Bay, Baianus Sinus, near Naples. We performed X-ray computed micro-tomography (μ-XCT) at beamline 8.3.2 of the Advanced Light Source (ALS) at Lawrence Berkeley Laboratories to segment the complex composite without damaging the specimen. We isolated certain relict sub-spherical voids and illustrated crystal morphologies with 3-D reconstructions. We then used beamline 12.3.2 at the ALS to provide highly accurate identifications of diverse crystal phases in various mortar components - relict lime clasts, tuff or pumice clasts, cementitious matrix and relict voids - in sites previously identified and characterized with petrogaphic techniques. X-ray micro-fluorescence (μ-XRF) mapping provided calcium and iron maps of the sites, which were useful in selecting fine-scale areas for scanning transmission X-ray micro-diffraction (μ-XRD) mapping at high spatial resolution, about 1 micron. The μ-XRD analyses utilized both monochromatic and polychromatic light measurements. Polychromatic light was more appropriate for phases with grain sizes larger than the doubly focused X-ray beam, about 1 x

  13. Preparation, characterization and optoelectronic properties of nanodiamonds doped zinc oxide nanomaterials by a ball milling technique

    NASA Astrophysics Data System (ADS)

    Ullah, Hameed; Sohail, Muhammad; Malik, Uzma; Ali, Naveed; Bangash, Masroor Ahmad; Nawaz, Mohsan

    2016-07-01

    Zinc oxide (ZnO) is one of the very important metal oxides (MOs) for applications in optoelectronic devices which work in the blue and UV regions. However, to meet the challenges of obtaining ZnO nanomaterials suitable for practical applications, various modifications in physico-chemical properties are highly desirable. One of the ways adopted for altering the properties is to synthesize composite(s) of ZnO with various reinforcements. Here we report on the tuning of optoelectronic properties of ZnO upon doping by nanodiamonds (NDs) using the ball milling technique. A varying weight percent (wt.%) of NDs were ball milled for 2 h with ZnO nanoparticles prepared by a simple precipitation method. The effects of different parameters, the calcination temperature of ZnO, wt.% of NDs and mechanical milling upon the optoelectronic properties of the resulting ZnO–NDs nanocomposites have been investigated. The ZnO–NDs nanocomposites were characterized by IR spectroscopy, powder x-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX). The UV-vis spectroscopy revealed the alteration in the bandgap energy (Eg ) of ZnO as a function of the calcination temperature of ZnO, changing the concentration of NDs, and mechanical milling of the resulting nanocomposites. The photoluminescence (PL) spectroscopy showed a decrease in the deep level emission (DLE) peaks and an increase in near-band-edge transition peaks as a result of the increasing concentration of NDs. The decrease in DLE and increase in band to band transition peaks were due to the strong interaction between the NDs and the Zn+; consequently, the Zn+ concentration decreased on the interstitial sites.

  14. Surface acoustic wave technique for the characterization of porous properties of microporous silicate thin films

    NASA Astrophysics Data System (ADS)

    Hietala, Susan Leslie

    1997-12-01

    Features of gas adsorption onto sol-gel derived microporous silicate thin films, for characterization of porous properties, are detailed using a surface acoustic wave (SAW) technique. Mass uptake and film effective modulus changes calculated from the SAW data are investigated in detail. The effects of stress and surface tension on the SAW sensor are calculated and found to be negligible in these experiments. Transient behavior recorded during nitrogen adsorption at 77 K is discussed in the context of mass uptake and effective modulus contributions. The time constant associated with the effective modulus calculation is consistent with that of diffusivity of nitrogen into a 5A zeolite. Further calculations indicate that the transient behavior is not due to thermal effects. A unique dual sensor SAW experiment to decouple the mass and effective modulus contributions to the frequency response was performed in conjunction with a Silicon beam-bending experiment. The beam-bending experiment results in a calculation of stress induced during adsorption of methanol on a microporous silicate thin film. The decoupled mass and effective modulus calculated from the SAW data have similar shaped isotherms, and are quite different from that of the stress developed in the Silicon beam. The total effective modulus change calculated from the SAW data is consistent with that calculated using Gassmann's equation. The SAW system developed for this work included unique electronics and customized hardware which is suitable for work under vacuum and at temperatures from 77K to 473K. This unique setup is suitable for running thin film samples on a Micromeritics ASAP 2000 Gas Adsorption unit in automatic mode. This setup is also general enough to be compatible with a custom gas adsorption unit and the beam bending apparatus, both using standard vacuum assemblies.

  15. Isolation and characterization of Mycobacterium bovis strains from indigenous Zambian cattle using Spacer oligonucleotide typing technique

    PubMed Central

    2009-01-01

    Background Bovine tuberculosis (BTB), caused by Mycobacterium bovis, has remained a major source of concern to public health officials in Zambia. Previous investigations have used traditional epidemiological methods that are unable to identify the causative agent and from which dynamics of disease dispersion is difficult to discern. The objective of this study was to isolate, characterize and determine the genetic diversity and relatedness of M. bovis from major cattle rearing districts in Zambia by spoligotyping. A total of 695 carcasses were examined and 98 tissues had gross post-mortem lesions compatible with BTB. Results Forty-two out of the ninety-eight suspected tissues examined had culture properties characteristic of mycobacteria from which 31 isolates yielded interpretable spoligotypes. This technique showed good discriminatory power (HGDI = 0.98), revealing 10 different spoligotype patterns. Twenty-seven isolates belonged to one cluster with more than 95% similarity and inside the cluster, one predominant spoligotype was found in 20 (64.5%) of the isolates tested. The highest number of spoligotypes was observed among samples from Namwala district. Spoligotypes from 26 (83.9%) of the isolates belonged to five spoligotypes that have been reported before while the remaining 5 (16.1%) isolates had unique spoligotypes that are being reported for the first time; these have been assigned numbers SB1763 to SB1767. Five of the 6 districts had the predominant spoligotype (SB0120). Conclusion The study has described the dispersion patterns of M. bovis in Zambian cattle for the first time and has identified 5 spoligotype patterns specific to Zambia. The observation of an overlap in the spoligotype pattern SB0120 in 5 of the 6 districts suggests the probability of sharing a common source of infection. PMID:19619309

  16. Mechanical Characterization of Copper-Copper Wires Joined by Friction Welding Using Instrumented Indentation Technique

    NASA Astrophysics Data System (ADS)

    Morales, M.; Xuriguera, E.; Martínez, M.; Padilla, J. A.; Molera, J.; Ferrer, N.; Segarra, M.; Espiell, F.

    2014-11-01

    Friction welding samples of both the fire-refined high-conductivity (FRHC) and electrolytically tough pitch (ETP) copper alloy wires have been mechanically characterized by instrumented indentation technique and tensile test. Hardness profiles in the perpendicular direction to the weld interface, in both the central and peripheral zones, of the as-welded FRHC-FRHC and ETP-ETP samples have been investigated at nano-/micrometric scale. The microstructures of welds have been observed using both the optical microscopy and scanning electronic microscopy. The results show the typical friction welding zones: the interface zone, the thermo-mechanically affected zone (TMAZ), and the transition zone between the TMAZ and the base metal zone (BMZ) that present a microstructure and hardness close to the base metal. No presence of a heat-affected zone is observed. Although both welds show the same tendency in hardness distribution, FHRC-FHRC weld presents a TMAZ narrower than ETP-ETP one, which produces a stronger drop in hardness with increasing of the distance from welding central line, and a higher difference in hardness between the central and peripheral zones. The tensile tests of ETP-ETP welds showed that all samples broke by the BMZ that is far away from the interface of the welded joint, while the most of the FRHC-FRHC welds are broken at the TMAZ region at low strengths. These appreciable differences in mechanical properties for the FHRC-FHRC welds are probably generated by a stronger variation in their microstructural properties. Therefore, it may justify the welding failures in the FHRC-FHRC weld at the typical tensile stress for an industrial cold-drawn process of wires.

  17. Characterization of nitrogen-rich silicon nitride films grown by the electron cyclotron resonance plasma technique

    NASA Astrophysics Data System (ADS)

    Wang, L.; Reehal, H. S.; Martínez, F. L.; San Andrés, E.; del Prado, A.

    2003-07-01

    Amorphous hydrogenated silicon nitride films have been deposited by the electron cyclotron resonance plasma technique, using N2 and SiH4 as precursor gases. The gas flow ratio, deposition temperature and microwave power have been varied in order to study their effect on the properties of the films, which were characterized by Rutherford back-scattering spectrometry, elastic recoil detection analysis (ERDA), Fourier transform infrared spectroscopy and ellipsometry. All samples show N/Si ratios near or above the stoichiometric value (N/Si = 1.33). The hydrogen content determined from ERDA measurements is significantly higher than the amount detected by infrared spectroscopy, evidencing the presence of non-bonded H. As the N2/SiH4 gas flow ratio is increased (by decreasing the SiH4 partial pressure), the Si content decreases and the N-H concentration increases, while the N content remains constant, resulting in an increase of the N/Si ratio. The decrease of the Si content causes a decrease of the refractive index and the density of the film, while the growth ratio also decreases due to the limiting factor of the SiH4 partial pressure. The infrared Si-N stretching band shifts to higher wavenumbers as the N-H concentration increases. The increase of deposition temperature promotes the release of H, resulting in a higher incorporation of N and Si into the film and a decrease of the N/Si ratio. The effect of increasing the microwave power is analogous to increasing the N2/SiH4 ratio, due to the increase in the proportion of nitrogen activated species.

  18. Investigation of new devices and characterization techniques in the III-V semiconductor system

    NASA Astrophysics Data System (ADS)

    Cheng, Xiao-Chang

    This thesis concerns the investigation of novel devices and material characterization techniques in the III-V semiconductor system. In the first part of the thesis, we demonstrate that novel devices, such as avalanche photodiodes and tunnel switch diodes, can be fabricated from InAs/GaSb/AlSb heterostructures by molecular beam epitaxy (MBE). In the second part of the thesis, ballistic electron emission microscopy (BEEM) is employed to examine the local band offset in these heterostructures, which is often found to be crucial in device design. In the avalanche photodiode study, devices with near infrared response out to 1.74 mum were demonstrated. Two types of devices were investigated: those with a bulk Al0.04Ga0.96Sb multiplication region and those with a GaSb/AlSb superlattice multiplication region. Both types of devices were implemented in a MBE grown p-n + structure that uses a selectively doped InAs/AlSb superlattice as the n-type layer. This particular structure was optimized through several design, fabrication, characterization cycles. It was found that the photodiode dark current depended critically on the InAs/AlSb superlattice period and the resulting band offset at the p-n+ heterojunction. The InAs/AlSb superlattice was henceforth optimized by using a three stage design. The ionization rates in bulk multiplication layer devices were measured and found to be consistent with hole impact ionization enhancement in Al0.04Ga0.96Sb. However, direct comparison with superlattice multiplication layer devices revealed the latter to be more promising due to more effective dark current suppression from the larger band gap of the superlattice multiplication layer. The second device studied is the tunnel switch diode. We have fabricated the first such device in the antimonide material system and obtained characteristic "S" shaped I-V curves from these devices. The epilayer and barrier dependence of tunnel diode switching were studied and found to deviate significantly

  19. Modular error embedding

    DOEpatents

    Sandford, II, Maxwell T.; Handel, Theodore G.; Ettinger, J. Mark

    1999-01-01

    A method of embedding auxiliary information into the digital representation of host data containing noise in the low-order bits. The method applies to digital data representing analog signals, for example digital images. The method reduces the error introduced by other methods that replace the low-order bits with auxiliary information. By a substantially reverse process, the embedded auxiliary data can be retrieved easily by an authorized user through use of a digital key. The modular error embedding method includes a process to permute the order in which the host data values are processed. The method doubles the amount of auxiliary information that can be added to host data values, in comparison with bit-replacement methods for high bit-rate coding. The invention preserves human perception of the meaning and content of the host data, permitting the addition of auxiliary data in the amount of 50% or greater of the original host data.

  20. Structural Embeddings: Mechanization with Method

    NASA Technical Reports Server (NTRS)

    Munoz, Cesar; Rushby, John

    1999-01-01

    The most powerful tools for analysis of formal specifications are general-purpose theorem provers and model checkers, but these tools provide scant methodological support. Conversely, those approaches that do provide a well-developed method generally have less powerful automation. It is natural, therefore, to try to combine the better-developed methods with the more powerful general-purpose tools. An obstacle is that the methods and the tools often employ very different logics. We argue that methods are separable from their logics and are largely concerned with the structure and organization of specifications. We, propose a technique called structural embedding that allows the structural elements of a method to be supported by a general-purpose tool, while substituting the logic of the tool for that of the method. We have found this technique quite effective and we provide some examples of its application. We also suggest how general-purpose systems could be restructured to support this activity better.

  1. Characterization of Deficiencies in the Frequency Domain Forced Response Analysis Technique for Supersonic Turbine Bladed Disks

    NASA Technical Reports Server (NTRS)

    Brown, Andrew M.; Schmauch, Preston

    2012-01-01

    Turbine blades in rocket and jet engine turbomachinery experience enormous harmonic loading conditions. These loads result from the integer number of upstream and downstream stator vanes as well as the other turbine stages. Assessing the blade structural integrity is a complex task requiring an initial characterization of whether resonance is possible and then performing a forced response analysis if that condition is met. The standard technique for forced response analysis in rocket engine turbines is to decompose a computational fluid dynamics (CFD).generated flow field into its harmonic components, and to then perform a frequency response analysis at the problematic natural frequencies using cyclically symmetric structural dynamic models. Recent CFD analysis and water-flow testing at NASA/MSFC, though, indicates that this technique may miss substantial harmonic and non ]harmonic excitation sources that become present in complex flows. This complex content can only be captured by a CFD flow field encompassing at least an entire revolution. A substantial development effort to create a series of software programs to enable application of the 360 degree forcing function in a frequency response analysis on cyclic symmetric models has been completed (to be described in a future paper), but the question still remains whether the frequency response analysis itself is capable of capturing the excitation content sufficiently. Two studies comparing frequency response analysis with transient response analysis, therefore, of bladed-disks undergoing this complex flow environment have been performed. The first is of a bladed disk with each blade modeled by simple beam elements and the disk modeled with plates (using the finite element code MSC/NASTRAN). The focus of this model is to be representative of response of realistic bladed disks, and so the dimensions are roughly equivalent to the new J2X rocket engine 1st stage fuel pump turbine. The simplicity of the model allows

  2. Split-tip scanning capacitance microscopy (SSCM): Special techniques in surface characterization and measurements

    NASA Astrophysics Data System (ADS)

    Clark, Beverly Andrew, III

    Hallen). This work invents and develops a new technique for electrical, electro-optical, and topographical characterization at the nanoscale. Split-tip scanning capacitance microscopy (SSCM) offers advantages over other scanning probe methods. The dependence of the measurements on sample characteristics is reduced, and analysis is simplified by having both electrodes secured to the probe. This feature allows non-conducting, as well as conducting surfaces to be imaged without loss of optical or capacitance resolution. SSCM allows surface measurements without destroying the sample of interest and does not require special surface preparation. To develop this new technique, the project focused on the following: (1) shear-force feedback as an accurate tip-sample distance controller; (2) imaging techniques for irregular sample surfaces; (3) development of computational model for simulating split-tip measurements; (4) split-tip integration into a conventional near-field scanning optical microscope; (5) contrast modeling for surface structures; (6) tip-sample approach capacitance measurements as a stringent test of SSCM. We show that a non-linear tip sample interaction dominates the shear force feedback signal evidenced by a change in the resonance frequency as the tip approaches the sample. Shear force feedback relies on a decrease in the signal amplitude at the operating frequency. We present data and a numerical model describing the time response and how this nonlinear interaction can be used to speed up the response. We demonstrate the imaging of irregular surfaces such as paint samples and show the distribution of pigment quantified by the peak in the histogram of optical signal versus separation at the nano- to micron scale illuminates the length-scale of failure in paint samples. We compare a high quality paint sample with one that fails a standard quality control test based upon visual inspection. Features such as pigment clumping and pigment density fluctuations

  3. Rock surface roughness measurement using CSI technique and analysis of surface characterization by qualitative and quantitative results

    NASA Astrophysics Data System (ADS)

    Mukhtar, Husneni; Montgomery, Paul; Gianto; Susanto, K.

    2016-01-01

    In order to develop image processing that is widely used in geo-processing and analysis, we introduce an alternative technique for the characterization of rock samples. The technique that we have used for characterizing inhomogeneous surfaces is based on Coherence Scanning Interferometry (CSI). An optical probe is first used to scan over the depth of the surface roughness of the sample. Then, to analyse the measured fringe data, we use the Five Sample Adaptive method to obtain quantitative results of the surface shape. To analyse the surface roughness parameters, Hmm and Rq, a new window resizing analysis technique is employed. The results of the morphology and surface roughness analysis show micron and nano-scale information which is characteristic of each rock type and its history. These could be used for mineral identification and studies in rock movement on different surfaces. Image processing is thus used to define the physical parameters of the rock surface.

  4. Embedded solution for a microwave moisture meter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this paper, the conversion of a PC or laptop-controlled microwave moisture meter to a stand-alone meter hosting its own embedded system is discussed. The moisture meter is based on the free-space transmission measurement technique and uses low-intensity microwaves to measure the attenuation and p...

  5. Nondestructive technique for the characterization of the pore size distribution of soft porous constructs for tissue engineering.

    PubMed

    Safinia, Laleh; Mantalaris, Athanasios; Bismarck, Alexander

    2006-03-28

    Polymer scaffolds tailored for tissue engineering applications possessing the desired pore structure require reproducible fabrication techniques. Nondestructive, quantitative methods for pore characterization are required to determine the pore size and its distribution. In this study, a promising alternative to traditional pore size characterization techniques is presented. We introduce a quantitative, nondestructive and inexpensive method to determine the pore size distribution of large soft porous solids based on the on the displacement of a liquid, that spreads without limits though a porous medium, by nitrogen. The capillary pressure is measured and related to the pore sizes as well as the pore size distribution of the narrowest bottlenecks of the largest interconnected pores in a porous medium. The measured pore diameters correspond to the narrowest bottleneck of the largest pores connecting the bottom with the top surface of a given porous solid. The applicability and reproducibility of the breakthrough technique is demonstrated on two polyurethane foams, manufactured using the thermally induced phase separation (TIPS) process, with almost identical overall porosity (60-70%) but very different pore morphology. By selecting different quenching temperatures to induce polymer phase separation, the pore structure could be regulated while maintaining the overall porosity. Depending on the quenching temperature, the foams exhibited either longitudinally oriented tubular macropores interconnected with micropores or independent macropores connected to adjacent pores via openings in the pore walls. The pore size and its distribution obtained by the breakthrough test were in excellent agreement to conventional characterization techniques, such as scanning electron microscopy combined with image analysis, BET technique, and mercury intrusion porosimetry. This technique is suitable for the characterization of the micro- and macropore structure of soft porous solids

  6. A new three-dimensional electromechanical impedance model for an embedded dual-PZT transducer

    NASA Astrophysics Data System (ADS)

    Wang, Dansheng; Li, Zhi; Zhu, Hongping

    2016-07-01

    In the past twenty years, the electromechanical (EM) impedance technique has been investigated extensively in the mechanical, aviation and civil engineering fields. Many different EM impedance models have been proposed to characterize the interaction between the surface-bonded PZT transducer and the host structure. This paper formulates a new three-dimensional EM impedance model characterizing the interaction between an embedded circle dual-PZT transducer and the host structure based on the effective impedance concept. The proposed model is validated by experimental results from a group of smart cement cubes, in which three circle dual-PZT transducers are embedded respectively. In addition, a new EM impedance measuring method for the dual-PZT transducer is also introduced. In the measuring method, only a common signal generator and an oscilloscope are needed, by which the exciting and receiving voltage signals are obtained respectively. Combined with fast Fourier transform the EM impedance signatures of the dual-PZT transducers are obtained.

  7. Characterization of Carbon Dioxide Washout Measurement Techniques in the Mark-III Space Suit

    NASA Technical Reports Server (NTRS)

    Norcross, J.; Bekdash, O.; Meginnis, I.

    2016-01-01

    Providing adequate carbon dioxide (CO2) washout is essential to the reduction of risk in performing suited operations. Long term CO2 exposure can lead to symptoms such as headache, lethargy, dizziness, and in severe cases can lead to unconsciousness and death. Thus maintaining adequate CO2 washout in both ground testing and during in flight EVAs is a requirement of current and future suit designs. It is necessary to understand the inspired CO2 of suit wearers such that future requirements for space suits appropriately address the risk of inadequate washout. Testing conducted by the EVA Physiology Laboratory at the NASA Johnson Space Center aimed to characterize a method for noninvasively measuring inspired oronasal CO2 under pressurized suited conditions in order to better inform requirements definition and verification techniques for future CO2 washout limits in space suits. Prior work conducted by the EPL examined several different wearable, respirator style, masks that could be used to sample air from the vicinity surround the nose and mouth of a suited test subject. Previously published studies utilized these masks, some being commercial products and some novel designs, to monitor CO2 under various exercise and flow conditions with mixed results for repeatability and/or consistency between subjects. Based on a meta-analysis of those studies it was decided to test a nasal cannula as it is a commercially available device that is placed directly in the flow path of the user as they breathe. A nasal cannula was used to sample air inhaled by the test subjects during both rest and exercise conditions. Eight subjects were tasked with walking on a treadmill or operating an arm ergometer to reach target metabolic rates of 1000, 2000, and 3000 BTU/hr. Suit pressure was maintained at 4.3 psid for all tests, with supply flow rates of 6, 4, and 2 actual cubic feet per minute depending on the test condition. Each test configuration was conducted twice with subjects breathing

  8. Modified Embedded Atom Method

    Energy Science and Technology Software Center (ESTSC)

    2012-08-01

    Interatomic force and energy calculation subroutine to be used with the molecular dynamics simulation code LAMMPS (Ref a.). The code evaluated the total energy and atomic forces (energy gradient) according to a cubic spline-based variant (Ref b.) of the Modified Embedded Atom Method (MEAM) with a additional Stillinger-Weber (SW) contribution.

  9. Community-Embedded Learning

    ERIC Educational Resources Information Center

    Kazmer, Michelle M.

    2005-01-01

    Online learners often stay located in, and tied to, their communities, kinship networks, households, and workplaces. Institutions providing online education can thus create ties to communities as students draw their learning into networks in which they are already embedded. Frequent interactions across multiple media that are afforded by…

  10. Flexible embedding of networks

    NASA Astrophysics Data System (ADS)

    Fernandez-Gracia, Juan; Buckee, Caroline; Onnela, Jukka-Pekka

    We introduce a model for embedding one network into another, focusing on the case where network A is much bigger than network B. Nodes from network A are assigned to the nodes in network B using an algorithm where we control the extent of localization of node placement in network B using a single parameter. Starting from an unassigned node in network A, called the source node, we first map this node to a randomly chosen node in network B, called the target node. We then assign the neighbors of the source node to the neighborhood of the target node using a random walk based approach. To assign each neighbor of the source node to one of the nodes in network B, we perform a random walk starting from the target node with stopping probability α. We repeat this process until all nodes in network A have been mapped to the nodes of network B. The simplicity of the model allows us to calculate key quantities of interest in closed form. By varying the parameter α, we are able to produce embeddings from very local (α = 1) to very global (α --> 0). We show how our calculations fit the simulated results, and we apply the model to study how social networks are embedded in geography and how the neurons of C. Elegans are embedded in the surrounding volume.

  11. Embedded-monolith armor

    DOEpatents

    McElfresh, Michael W.; Groves, Scott E; Moffet, Mitchell L.; Martin, Louis P.

    2016-07-19

    A lightweight armor system utilizing a face section having a multiplicity of monoliths embedded in a matrix supported on low density foam. The face section is supported with a strong stiff backing plate. The backing plate is mounted on a spall plate.

  12. Media Embedded Interactions.

    ERIC Educational Resources Information Center

    Johnson, J. David

    A review of literature and two surveys, one of college students and one of a random sample of adults, were used to examine four aspects of media embedded interactions (social behavior in front of a TV or radio): their functions, their environment, their effects, and the reactions of the interactants to them. Television is seen as performing a…

  13. Characterization of synthetic hematite (α-Fe2O3) nanoparticles using a multi-technique approach.

    PubMed

    Colombo, Claudio; Palumbo, Giuseppe; Ceglie, Andrea; Angelico, Ruggero

    2012-05-15

    The aim of this work was to investigate the surface structure of aqueous hematite dispersions characterized by a large variability of morphology and particle size combining structural investigations obtained from Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM) techniques with in vitro particle size distributions and zeta potential measurements from Dynamic Light Scattering (DLS) technique, and we achieved a self-consistent and detailed characterization of hematite particles whose sizes and morphologies could be correlated to the synthesis conditions (type of added anion, Al substitution and pH). Surface AFM characterization provided an accurate analysis of particle microstructure and also indicated that the growth of microcrystals followed different surface roughness. DLS, AFM, and TEM techniques furnished complementary information on the average particle dimensions, whose variation could be attributed to the morphological difference of hematites, ranging from platy to regular or irregular hexagonal or ellipsoidal shape. Finally, a correlation between the average particle dimensions and the measured zeta potential was also been found in aqueous dilute suspensions characterized by neither pH nor-ionic-strength-control, for which a drop of zeta potential from positive to negative values was detected for hematite particle dimensions larger than a threshold size of ~150 nm. PMID:22381942

  14. Characterization of Carbon Dioxide Washout Measurement Techniques in the Mark-III Space Suit

    NASA Technical Reports Server (NTRS)

    Meginnis, I; Norcross, J.; Bekdash, O.

    2016-01-01

    It is essential to provide adequate carbon dioxide (CO2) washout in a space suit to reduce the risks associated with manned operations in space suits. Symptoms of elevated CO2 levels range from reduced cognitive performance and headache to unconsciousness and death at high levels of CO2. Because of this, NASA imposes limits on inspired CO2 levels for space suits when they are used in space and for ground testing. Testing and/or analysis must be performed to verify that a space suit meets CO2 washout requirements. Testing for developmental space suits has traditionally used an oronasal mask that collects CO2 samples at the left and rights sides of the mouth. Testing with this mask resulted in artificially elevated CO2 concentration measurements, which is most likely due to the dead space volume at the front of the mask. The mask also extends outward and into the supply gas stream, which may disrupt the washout effect of the suit supply gas. To mitigate these problems, a nasal cannula was investigated as a method for measuring inspired CO2 based on the assumptions that it is low profile and would not interfere with the designed suit gas flow path, and it has reduced dead space. This test series compared the performance of a nasal cannula to the oronasal mask in the Mark III space suit. Inspired CO2 levels were measured with subjects at rest and at metabolic workloads of 1000, 2000, and 3000 BTU/hr. Workloads were achieved by use of an arm ergometer or treadmill. Test points were conducted at air flow rates of 2, 4, and 6 actual cubic feet per minute, with a suit pressure of 4.3 psid. Results from this test series will evaluate the accuracy and repeatability across subjects of the nasal cannula collection method, which will provide rationale for using a nasal cannula as the new method for measuring inspired CO2 in a space suit. Proper characterization of sampling methods and of suit CO2 washout capability will better inform requirements definition and verification

  15. Characterization of a unique technique for culturing primary adult human epithelial progenitor/“stem cells”

    PubMed Central

    2012-01-01

    Background Primary keratinocytes derived from epidermis, oral mucosa, and urothelium are used in construction of cell based wound healing devices and in regenerative medicine. This study presents in vitro technology that rapidly expands keratinocytes in culture by growing monolayers under large volumes of serum-free, essential fatty acid free, low calcium medium that is replaced every 24 hrs. Methods Primary cell cultures were produced from epidermal skin, oral mucosa and ureter by trypsinization of tissue. Cells were grown using Epilife medium with growth factors under high medium volumes. Once densely confluent, the keratinocyte monolayer produced cells in suspension in the overlying medium that can be harvested every 24 hrs. over a 7–10 day period. The cell suspension (approximately 8 X 105 cells/ml) is poured into a new flask to form another confluent monolayer over 2–4 days. This new culture, in turn produced additional cell suspensions that when serially passed expand the cell strain over 2–3 months, without the use of enzymes to split the cultures. The cell suspension, called epithelial Pop Up Keratinocytes (ePUKs) were analyzed for culture expansion, cell size and glucose utilization, attachment to carrier beads, micro-spheroid formation, induction of keratinocyte differentiation, and characterized by immunohistochemistry. Results The ePUKs expanded greatly in culture, attached to carrier beads, did not form micro-spheroids, used approximately 50% of medium glucose over 24 hrs., contained a greater portion of smaller diameter cells (8–10 microns), reverted to classical appearing cultures when returned to routine feeding schedules (48 hrs. and 15 ml/T-75 flask) and can be differentiated by either adding 1.2 mM medium calcium, or essential fatty acids. The ePUK cells are identified as cycling (Ki67 expressing) basal cells (p63, K14 expressing). Conclusions Using this primary culture technique, large quantities of epithelial cells can

  16. Development of nanoindentation techniques for characterizing local mechanical properties of soft materials

    NASA Astrophysics Data System (ADS)

    Wood, Charles David

    Indentation has become a popular mechanical characterization technique due to the promise of high-resolution maps of material stiffness. Due to the far-reaching nature of the testing framework, indentation tests can occur on nearly any material type and on any length scale. In this dissertation, we will look at three different materials systems and demonstrate new and unique uses for the indentation framework. These results will provide information not available by other methodologies, thereby proving its universal value. Two different indentation schemes are employed, either probing the top surface of cross-section samples or by probing into the thickness of a thin film. The differences between each of the studies highlight the importance of sample geometry/orientation, contact conditions, material response, etc. First, we will use indentation to probe local regions near carbon nanotube/glass fiber hybrid composites in an epoxy matrix. Indentations were performed to determine the radial gradient of modulus enhancements from the glass fiber surface. The results from indentation demonstrated that spatial reinforcement due to the presence of nanotubes was tied to fiber morphology and not the local morphology of carbon nanotubes. Secondly, we look at rubber and filler interaction on two different levels; macroscale and nanoscale. On the nanoscale, we show that interactions at the filler/polymer interface create regions of altered polymer mobility. These regions are influenced by geometric and chemical confinement, which increase the stiffness of these small regions (< 200nm). We employ two different indentation methods to highlight how contact orientation determines the nature of our results. Ultra-soft materials, such as hydrogels and tissues, pose rather unique challenges when they are tested mechanically. However, with tissues and gels, the sensitivity of the machines is challenged and therefore protocols must be developed to produce accurate results. We validate

  17. Common Practice Lightning Strike Protection Characterization Technique to Quantify Damage Mechanisms on Composite Substrates

    NASA Technical Reports Server (NTRS)

    Szatkowski, George N.; Dudley, Kenneth L.; Koppen, Sandra V.; Ely, Jay J.; Nguyen, Truong X.; Ticatch, Larry A.; Mielnik, John J.; Mcneill, Patrick A.

    2013-01-01

    heating parameters which occur during lightning attachment. Following guidance defined in the universal common practice LSP test documents, protected and unprotected CFRP panels were evaluated at 20, 40 and 100KAmps. This report presents analyzed data demonstrating the scientific usefulness of the common practice approach. Descriptions of the common practice CFRP test articles, LSP test bed fixture, and monitoring techniques to capture the electrical, mechanical and thermal parameters during lightning attachment are presented here. Two methods of measuring the electrical currents were evaluated, inductive current probes and a newly developed fiberoptic sensor. Two mechanical displacement methods were also examined, optical laser measurement sensors and a digital imaging correlation camera system. Recommendations are provided to help users implement the common practice test approach and obtain LSP test characterizations comparable across data sets.

  18. The cavity-embedded-cooper pair transistor

    NASA Astrophysics Data System (ADS)

    Chen, Fei

    Nearly eight decades after Erwin Schrodinger proposed his famous cat paradox, the boundary between classical and quantum physics is becoming accessible to experimental study in condensed matter systems, in which macroscopic and microscopic degrees of freedom interact with each other. The cavity-embedded-Cooper pair transistor (cCPT) is an ideal candidate for such a study in that it is not only strongly and intrinsically nonlinear but also fully quantum mechanical. A novel technique, based on the circuit quantum electrodynamics architecture, is first introduced for applying a dc bias to a high-Q superconducting microwave cavity. The development and investigation of the cCPT system, in which a Cooper pair transistor acting as a single artificial atom is directly coupled to an on-chip dc-biased high-Q resonator, is then presented. Self-oscillations in the cCPT, internally driven by the ac Josephson effect, demonstrate the strong and phase coherent coupling between matter and light in the cCPT. Meanwhile, photons continually produced by the system are collected and characterized by quantum state tomography, which indicates the non-classical nature of the emitted light and the nonlinear quantum dynamics of the cCPT system.

  19. Isometric embeddings of polyhedra

    NASA Astrophysics Data System (ADS)

    Minemyer, Barry

    An indefinite metric polyhedron is a triple (X, T, g) where X is a topological space, T is a simplicial triangulation of X with edge set E, and g is a function from E to the reals. g assigns to each k-dimensional simplex S a unique quadratic form on Rk, denoted by G(S). An indefinite metric polyhedron is called a Euclidean polyhedron if the form G(S) is positive definite for every simplex S. Rpq denotes R p + q endowed with the inner product of signature (p, q). Our first result is that every compact n-dimensional indefinite metric polyhedron with vertex set V admits a simplicial isometric embedding into Rqq where q = max{d, 2n + 1} and d = max{deg(v) | v is in V}. We can use the compact case to extend to the non-compact case, but only if we assume that d = max{deg(v) | v is in V} is less than infinity. Specifically, every (non-compact) indefinite metric polyhedron admits a simplicial isometric embedding into Rpp where p = 2q(d3 - d2 + d + 1) and q and d are defined as above. Finally we use results of Akopyan and Greene to prove that every n-dimensional indefinite metric polyhedron admits a piecewise linear isometric embedding into Rn2n. In Chapter 2 we prove that every short (1-Lipschitz) map from an n-dimensional Euclidean polyhedron into EN is epsilon close to a pl isometric embedding (for anyepsilon > 0) provided N ≥ 3n. We can relax the dimensionality of the Euclidean space to 2n + 1 if we allow our map to be continuous instead of pl. These results are extensions of a result due to Akopyan. We provide a detailed proof of Akopyan's Theorem, as the only currently available proof is in Russian. The remaining results in this work are applications of our continuous isometric embedding theorem above. This result is used to prove that every Pro-Euclidean space of rank at most n admits an isometric embedding into E2n + 1. The result, as well as a theorem due to Bridson, also allows for an approximate isometric embedding theorem for geodesic metric spaces with

  20. Global string embeddings for the nilpotent Goldstino

    NASA Astrophysics Data System (ADS)

    García-Etxebarria, Iñaki; Quevedo, Fernando; Valandro, Roberto

    2016-02-01

    We discuss techniques for embedding a nilpotent Goldstino sector both in weakly coupled type IIB compactifications and F-theory models at arbitrary coupling, providing examples of both scenarios in semi-realistic compactifications. We start by showing how to construct a local embedding for the nilpotent Goldstino in terms of an anti D3-brane in a local conifold throat, and then discuss how to engineer the required local structure in globally consistent compact models. We present two explicit examples, the last one supporting also chiral matter and Kähler moduli stabilisation.

  1. Electromagnetic diagnostic techniques for hypervelocity projectile detection, velocity measurement, and size characterization: Theoretical concept and first experimental test

    SciTech Connect

    Uhlig, W. Casey; Heine, Andreas

    2015-11-14

    A new measurement technique is suggested to augment the characterization and understanding of hypervelocity projectiles before impact. The electromagnetic technique utilizes magnetic diffusion principles to detect particles, measure velocity, and indicate relative particle dimensions. It is particularly suited for detection of small particles that may be difficult to track utilizing current characterization methods, such as high-speed video or flash radiography but can be readily used for large particle detection, where particle spacing or location is not practical for other measurement systems. In this work, particles down to 2 mm in diameter have been characterized while focusing on confining the detection signal to enable multi-particle characterization with limited particle-to-particle spacing. The focus of the paper is on the theoretical concept and the analysis of its applicability based on analytical and numerical calculation. First proof-of-principle experimental tests serve to further validate the method. Some potential applications are the characterization of particles from a shaped-charge jet after its break-up and investigating debris in impact experiments to test theoretical models for the distribution of particles size, number, and velocity.

  2. Electromagnetic diagnostic techniques for hypervelocity projectile detection, velocity measurement, and size characterization: Theoretical concept and first experimental test

    NASA Astrophysics Data System (ADS)

    Uhlig, W. Casey; Heine, Andreas

    2015-11-01

    A new measurement technique is suggested to augment the characterization and understanding of hypervelocity projectiles before impact. The electromagnetic technique utilizes magnetic diffusion principles to detect particles, measure velocity, and indicate relative particle dimensions. It is particularly suited for detection of small particles that may be difficult to track utilizing current characterization methods, such as high-speed video or flash radiography but can be readily used for large particle detection, where particle spacing or location is not practical for other measurement systems. In this work, particles down to 2 mm in diameter have been characterized while focusing on confining the detection signal to enable multi-particle characterization with limited particle-to-particle spacing. The focus of the paper is on the theoretical concept and the analysis of its applicability based on analytical and numerical calculation. First proof-of-principle experimental tests serve to further validate the method. Some potential applications are the characterization of particles from a shaped-charge jet after its break-up and investigating debris in impact experiments to test theoretical models for the distribution of particles size, number, and velocity.

  3. Optical speckles of blood proteins embedded in porous glassy substrate

    NASA Astrophysics Data System (ADS)

    Holden, T.; Dehipawala, S.; Kokkinos, D.; Berisha, A.; Cheung, E.; Nguyen, A.; Golebiewska, U.; Schneider, P.; Tremberger, G., Jr.; Lieberman, D.; Cheung, T.

    2012-03-01

    Blood protein molecules could be embedded in porous glassy substrate with 10-nm pores. The embedding principle is based on blood cell dehydration with the destruction of the cell membrane, and reconstitution and centrifuge could yield a suitable solution for doping into a porous glassy medium. The doped glassy substrate speckle pattern under laser illumination could be used to characterize the protein size distribution. Calibration with known protein embedded samples would result in an optical procedure for the characterization of a blood sample. Samples embedded with larger kilo-Dalton protein molecule show more variation in the speckle patterns, consistent with protein folding interaction inside a pore cavity. A regression model has been used to correlate the protein molecule sizes with speckle sizes. The use of diffusion mean free path information to study protein folding in the embedding process is briefly discussed.

  4. Testing framework for embedded languages

    NASA Astrophysics Data System (ADS)

    Leskó, Dániel; Tejfel, Máté

    2012-09-01

    Embedding a new programming language into an existing one is a widely used technique, because it fastens the development process and gives a part of a language infrastructure for free (e.g. lexical, syntactical analyzers). In this paper we are presenting a new advantage of this development approach regarding to adding testing support for these new languages. Tool support for testing is a crucial point for a newly designed programming language. It could be done in the hard way by creating a testing tool from scratch, or we could try to reuse existing testing tools by extending them with an interface to our new language. The second approach requires less work, and also it fits very well for the embedded approach. The problem is that the creation of such interfaces is not straightforward at all, because the existing testing tools were mostly not designed to be extendable and to be able to deal with new languages. This paper presents an extendable and modular model of a testing framework, in which the most basic design decision was to keep the - previously mentioned - interface creation simple and straightforward. Other important aspects of our model are the test data generation, the oracle problem and the customizability of the whole testing phase.

  5. Observational and Data Reduction Techniques to Optimize Mineralogical Characterizations of Asteroid Surface Materials

    NASA Technical Reports Server (NTRS)

    Gaffey, M. J.

    2003-01-01

    Mineralogy is the key to determining the compositional history of the asteroids and to determining the genetic relationships between the asteroids and meteorites. The most sophisticated remote mineralogical characterizations involve the quantitative extraction of specific diagnostic parameters from reflectance spectra and the use of quantitative interpretive calibrations to determine the presence, abundance and/or composition of mineral phases in a surface material. Although this approach is potentially subject to systematic errors, it provides the only consistent set of asteroid surface material characterizations.

  6. Real-time technique for the characterization of tunable single-frequency lasers

    SciTech Connect

    Strzelecki, E.M.; Cohen, D.A.; Corzine, S.W.; Karin, J.R.; Coldren, L.A.

    1988-06-27

    An all-fiber Mach--Zehnder interferometric system has been developed for characterization of tunable semiconductor lasers. The tuning rate, range, and linearity of directly frequency-modulated lasers as well as laser linewidth are measured using the same system. To investigate the features of the system and demonstrate its usefulness, 1.3 ..mu..m coupled-cavity lasers, tunable with constant amplitude, were characterized. The effects of optical feedback on laser parameters have also been investigated.

  7. Characterization of Apollo Regolith by X-Ray and Electron Microbeam Techniques: An Analog for Future Sample Return Missions

    NASA Technical Reports Server (NTRS)

    Zeigler, Ryan A.

    2015-01-01

    The Apollo missions collected 382 kg of rock and regolith from the Moon; approximately 1/3 of the sample mass collected was regolith. Lunar regolith consists of well mixed rocks, minerals, and glasses less than 1-centimeter n size. The majority of most surface regolith samples were sieved into less than 1, 1-2, 2-4, and 4-10- millimiter size fractions; a portion of most samples was re-served unsieved. The initial characterization and classification of most Apollo regolith particles was done primarily by binocular microscopy. Optical classification of regolith is difficult because (1) the finest fraction of the regolith coats and obscures the textures of the larger particles, and (b) not all lithologies or minerals are uniquely identifiable optically. In recent years, we have begun to use more modern x-ray beam techniques [1-3], coupled with high resolution 3D optical imaging techniques [4] to characterize Apollo and meteorite samples as part of the curation process. These techniques, particularly in concert with SEM imaging of less than 1-millimeter regolith grain mounts, allow for the rapid characterization of the components within a regolith.

  8. MULTIPOLE EXPANSION TECHNIQUES FOR THE CALCULATION AND CHARACTERIZATION OF MOLECULAR ELECTROSTATIC POTENTIALS

    EPA Science Inventory

    The electrostatic interaction between a chemical and its site of biological action is often important in determining biological activity. In order to include this interaction in methods to assess the potential biological activity of large molecules, rapid and reliable techniques ...

  9. Industrial fouling: problem characterization, economic assessment, and review of prevention, mitigation, and accommodation techniques

    SciTech Connect

    Garrett-Price, B.A.; Smith, S.A.; Watts, R.L.

    1984-02-01

    A comprehensive overview of heat exchanger fouling in the manufacturing industries is provided. Specifically, this overview addresses: the characteristics of industrial fouling problems; the mitigation and accommodation techniques currently used by industry; and the types and magnitude of costs associated with industrial fouling. A detailed review of the fouling problems, costs and mitigation techniques is provided for the food, textile, pulp and paper, chemical, petroleum, cement, glass and primary metals industries.

  10. Nondestructive characterization of radioactive waste drums by gamma spectrometry: a Monte Carlo technique for efficiency calibration.

    PubMed

    Tzika, Faidra; Savidou, Anastasia; Stamatelatos, Ion E

    2007-11-01

    A semi-empirical non-destructive technique to assay radioactive waste drums is presented. The technique is based on gamma spectrometry performed using a portable NaI detector and Monte Carlo simulations using the MCNP code in order to derive the gamma ray detector efficiency for the volume source. The derivation of detector efficiency was performed assuming homogeneous distribution of the source activity within the matrix material. Moreover, the MCNP model was used to examine the effect of inhomogeneities in activity distribution, variation of matrix material density, and drum filling height on the accuracy of the technique, and to estimate the measurement bias. The technique was verified by estimating radioactivity levels in 25 drums containing ion exchange resin waste, and comparing the results of the non-destructive method against the analytical results of samples obtained from each drum. Satisfactory agreement between the two assay techniques was observed. The discussed technique represents a cost effective technology that can be used to assay low-activity, low-density waste drums provided the contribution to the gamma ray spectrum can be resolved. PMID:18049246

  11. Use of Iba Techniques to Characterize High Velocity Thermal Spray Coatings

    NASA Astrophysics Data System (ADS)

    Trompetter, W.; Markwitz, A.; Hyland, M.

    Spray coatings are being used in an increasingly wide range of industries to improve the abrasive, erosive and sliding wear of machine components. Over the past decade industries have moved to the application of supersonic high velocity thermal spray techniques. These coating techniques produce superior coating quality in comparison to other traditional techniques such as plasma spraying. To date the knowledge of the bonding processes and the structure of the particles within thermal spray coatings is very subjective. The aim of this research is to improve our understanding of these materials through the use of IBA techniques in conjunction with other materials analysis techniques. Samples were prepared by spraying a widely used commercial NiCr powder onto substrates using a HVAF (high velocity air fuel) thermal spraying technique. Detailed analysis of the composition and structure of the power particles revealed two distinct types of particles. The majority was NiCr particles with a significant minority of particles composing of SiO2/CrO3. When the particles were investigated both as raw powder and in the sprayed coating, it was surprising to find that the composition of the coating meterial remained unchanged during the coating process despite the high velocity application.

  12. An X-band waveguide measurement technique for the accurate characterization of materials with low dielectric loss permittivity.

    PubMed

    Allen, Kenneth W; Scott, Mark M; Reid, David R; Bean, Jeffrey A; Ellis, Jeremy D; Morris, Andrew P; Marsh, Jeramy M

    2016-05-01

    In this work, we present a new X-band waveguide (WR90) measurement method that permits the broadband characterization of the complex permittivity for low dielectric loss tangent material specimens with improved accuracy. An electrically long polypropylene specimen that partially fills the cross-section is inserted into the waveguide and the transmitted scattering parameter (S21) is measured. The extraction method relies on computational electromagnetic simulations, coupled with a genetic algorithm, to match the experimental S21 measurement. The sensitivity of the technique to sample length was explored by simulating specimen lengths from 2.54 to 15.24 cm, in 2.54 cm increments. Analysis of our simulated data predicts the technique will have the sensitivity to measure loss tangent values on the order of 10(-3) for materials such as polymers with relatively low real permittivity values. The ability to accurately characterize low-loss dielectric material specimens of polypropylene is demonstrated experimentally. The method was validated by excellent agreement with a free-space focused-beam system measurement of a polypropylene sheet. This technique provides the material measurement community with the ability to accurately extract material properties of low-loss material specimen over the entire X-band range. This technique could easily be extended to other frequency bands. PMID:27250447

  13. Characterization of biocatalysts prepared with Thermomyces lanuginosus lipase and different silica precursors, dried using aerogel and xerogel techniques.

    PubMed

    Barão, Carlos Eduardo; Daniel de Paris, Leandro; Dantas, João Henrique; Pereira, Matheus Mendonça; Filho, Lucio Cardozo; Ferreira de Castro, Heizir; Zanin, Gisella Maria; Faria de Moraes, Flavio; Faria Soares, Cleide Mara

    2014-01-01

    The use of lipases in industrial processes can result in products with high levels of purity and at the same time reduce pollutant generation and improve both selectivity and yields. In this work, lipase from Thermomyces lanuginosus was immobilized using two different techniques. The first involves the hydrolysis/polycondensation of a silica precursor (tetramethoxysilane (TMOS)) at neutral pH and ambient temperature, and the second one uses tetraethoxysilane (TEOS) as the silica precursor, involving the hydrolysis and polycondensation of the alkoxide in appropriate solvents. After immobilization, the enzymatic preparations were dried using the aerogel and xerogel techniques and then characterized in terms of their hydrolytic activities using a titrimetric method with olive oil and by the formation of 2-phenylethyl acetate in a transesterification reaction. The morphological properties of the materials were characterized using scanning electron microscopy, measurements of the surface area and pore size and volume, thermogravimetric analysis, and exploratory differential calorimetry. The results of the work indicate that the use of different silica precursors (TEOS or TMOS) and different drying techniques (aerogel or xerogel) can significantly affect the properties of the resulting biocatalyst. Drying with supercritical CO2 provided higher enzymatic activities and pore sizes and was therefore preferable to drying, using the xerogel technique. Thermogravimetric analysis and differential scanning calorimetry analyses revealed differences in behavior between the two biocatalyst preparations due to the compounds present. PMID:24078188

  14. Complementary use of flow and sedimentation field-flow fractionation techniques for size characterizing biodegradable poly(lactic acid) nanospheres

    PubMed Central

    Contado, Catia; Dalpiaz, Alessandro; Leo, Eliana; Zborowski, Maciej; Williams, P. Stephen

    2009-01-01

    Poly(lactic acid) nanoparticles were synthesized using a modified evaporation method, testing two different surfactants (sodium cholate and Pluronic F68) for the process. During their formulation the prodrug 5′-octanoyl-CPA (Oct-CPA) of the antiischemic N6-cyclopentyladenosine (CPA) was encapsulated. Three different purification methods were compared with respect to the influence of surfactant on the size characteristics of the final nanoparticle product. Flow and sedimentation field-flow fractionation techniques (FlFFF and SdFFF, respectively) were used to size characterize the five poly(lactic acid) particle samples. Two different combinations of carrier solution (mobile phase) were employed in the FlFFF analyses, while a solution of poly(vinyl alcohol) was used as mobile phase for the SdFFF runs. The separation performances of the two techniques were compared and the particle size distributions, derived from the fractograms, were interpreted with the support of observations by scanning electron microscopy. Some critical aspects, such as the carrier choice and the channel thickness determination for the FlFFF, have been investigated. This is the first comprehensive comparison of the two FFF techniques for characterizing non standard particulate materials. The two FFF techniques proved to be complementary and gave good, congruent and very useful information on the size distributions of the five poly(lactic acid) particle samples. PMID:17482199

  15. An X-band waveguide measurement technique for the accurate characterization of materials with low dielectric loss permittivity

    NASA Astrophysics Data System (ADS)

    Allen, Kenneth W.; Scott, Mark M.; Reid, David R.; Bean, Jeffrey A.; Ellis, Jeremy D.; Morris, Andrew P.; Marsh, Jeramy M.

    2016-05-01

    In this work, we present a new X-band waveguide (WR90) measurement method that permits the broadband characterization of the complex permittivity for low dielectric loss tangent material specimens with improved accuracy. An electrically long polypropylene specimen that partially fills the cross-section is inserted into the waveguide and the transmitted scattering parameter (S21) is measured. The extraction method relies on computational electromagnetic simulations, coupled with a genetic algorithm, to match the experimental S21 measurement. The sensitivity of the technique to sample length was explored by simulating specimen lengths from 2.54 to 15.24 cm, in 2.54 cm increments. Analysis of our simulated data predicts the technique will have the sensitivity to measure loss tangent values on the order of 10-3 for materials such as polymers with relatively low real permittivity values. The ability to accurately characterize low-loss dielectric material specimens of polypropylene is demonstrated experimentally. The method was validated by excellent agreement with a free-space focused-beam system measurement of a polypropylene sheet. This technique provides the material measurement community with the ability to accurately extract material properties of low-loss material specimen over the entire X-band range. This technique could easily be extended to other frequency bands.

  16. The Stellar Populations of Deeply Embedded Young Clusters: Near-Infrared Spectroscopy and Emergent Mass Distributions

    NASA Astrophysics Data System (ADS)

    Meyer, Michael R.

    1996-04-01

    The goal of this thesis is to test the following hypothesis: the initial distribution of stellar masses from a single "episode" of star formation is independent of the local physical conditions of the region. In other words, is the initial mass function (IMF) strictly universal over spatial scales d < 1 \\ pc and over time intervals Delta-tau << 3 x 10^6 yrs? We discuss the utility of embedded clusters in addressing this question. Using a combination of spectroscopic and photometric techniques, we seek to characterize emergent mass distributions of embedded clusters in order to compare them both with each other and with the field star IMF. Medium resolution (R=1000) near-infrared spectra obtainable with the current generation of NIR grating spectrographs can provide estimates of the photospheric temperatures of optically-invisible stars. Deriving these spectral types requires a three--step process; i) setting up a classification scheme based on near-infrared spectra of spectral standards; ii) understanding the effects of accretion on this classification scheme by studying optically-visible young stellar objects; and iii) applying this classification technique to the deeply embedded clusters. Combining near-infrared photometry with spectral types, accurate stellar luminosities can be derived for heavily reddened young stars thus enabling their placement in the H-R diagram. From their position in the H-R diagram, masses and ages of stars can be estimated from comparison with theoretical pre-main sequence evolutionary models. Because it is not practical to obtain complete spectroscopic samples of embedded cluster members, a technique is developed based solely on near-IR photometry for estimating stellar luminosities from flux--limited surveys. We then describe how spectroscopic surveys of deeply embedded clusters are necessary in order to adopt appropriate mass-luminosity relationships. Stellar luminosity functions constructed from complete extinction-limited samples

  17. Stellar Populations of Deeply Embedded Young Clusters: Near--Infrared Spectroscopy and Emergent Mass Distributions

    NASA Astrophysics Data System (ADS)

    Meyer, Michael R.

    1996-02-01

    The goal of this thesis is to test the following hypothesis: the initial distribution of stellar masses from a single ``episode'' of star formation is independent of the local physical conditions of the region. In other words, is the initial mass function (IMF) strictly universal over spatial scales d < 1 pc and over time intervals Δ τ << 3 × 106yrs? We discuss the utility of embedded clusters in addressing this question. Using a combination of spectroscopic and photometric techniques, we seek to characterize emergent mass distributions of embedded clusters in order to compare them both with each other and with the field star IMF. Medium resolution (R = 1000) near--infrared spectra obtainable with the current generation of NIR grating spectrographs can provide estimates of the photospheric temperatures of optically--invisible stars. Deriving these spectral types requires a three--step process; i) setting up a classification scheme based on near--infrared spectra of spectral standards; ii) understanding the effects of accretion on this classification scheme by studying optically--visible young stellar objects; and iii) applying this classification technique to the deeply embedded clusters. Combining near--infrared photometry with spectral types, accurate stellar luminosities can be derived for heavily reddened young stars thus enabling their placement in the H--R diagram. From their position in the H--R diagram, masses and ages of stars can be estimated from comparison with theoretical pre--main sequence evolutionary models. Because it is not practical to obtain complete spectroscopic samples of embedded cluster members, a technique is developed based solely on near--IR photometry for estimating stellar luminosities from flux--limited surveys. We then describe how spectroscopic surveys of deeply embedded clusters are necessary in order to adopt appropriate mass--luminosity relationships. Stellar luminosity functions constructed from complete extinction

  18. Characterization of the Etna volcanic emissions through an active biomonitoring technique (moss-bags): part 2--morphological and mineralogical features.

    PubMed

    Calabrese, S; D'Alessandro, W

    2015-01-01

    Volcanic emissions were studied at Mount Etna (Italy) by using moss-bags technique. Mosses were exposed around the volcano at different distances from the active vents to evaluate the impact of volcanic emissions in the atmosphere. Morphology and mineralogy of volcanic particulate intercepted by mosses were investigated using scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS). Particles emitted during passive degassing activity from the two active vents, Bocca Nuova and North East Crater (BNC and NEC), were identified as silicates, sulfates and halide compounds. In addition to volcanic particles, we found evidences also of geogenic, anthropogenic and marine spray input. The study has shown the robustness of this active biomonitoring technique to collect particles, very useful in active volcanic areas characterized by continuous degassing and often not easily accessible to apply conventional sampling techniques. PMID:25311770

  19. Statistical factor analysis technique for characterizing basalt through interpreting nuclear and electrical well logging data (case study from Southern Syria).

    PubMed

    Asfahani, Jamal

    2014-02-01

    Factor analysis technique is proposed in this research for interpreting the combination of nuclear well logging, including natural gamma ray, density and neutron-porosity, and the electrical well logging of long and short normal, in order to characterize the large extended basaltic areas in southern Syria. Kodana well logging data are used for testing and applying the proposed technique. The four resulting score logs enable to establish the lithological score cross-section of the studied well. The established cross-section clearly shows the distribution and the identification of four kinds of basalt which are hard massive basalt, hard basalt, pyroclastic basalt and the alteration basalt products, clay. The factor analysis technique is successfully applied on the Kodana well logging data in southern Syria, and can be used efficiently when several wells and huge well logging data with high number of variables are required to be interpreted. PMID:24296157

  20. The use of synchrotron radiation techniques in the characterization of strained semiconductor heterostructures and thin films [review article

    NASA Astrophysics Data System (ADS)

    Lamberti, C.

    2004-05-01

    In the last couple of decades, high-performance electronic and optoelectronic devices based on semiconductor heterostructures have been required to obtain increasingly strict and well-defined performances, needing a detailed control, at the atomic level, of the structural composition of the buried interfaces. This goal has been achieved by an improvement of the epitaxial growth techniques and by the parallel use of increasingly sophisticated characterization techniques. Among them, a leading role has been certainly played by those exploiting synchrotron radiation (SR) sources. In fact synchrotron radiation has distinct advantages as a photon source, notably high brilliance and continuous energy spectrum; by using the latter characteristic atomic selectivity can be obtained and this is of fundamental help to investigate the structural environment of atoms present only in a few angstrom (Å) thick interface layers of heterostructures. The third generation synchrotron radiation sources have allowed to reach the limit of measuring a monolayer of material, corresponding to about 10 14 atoms/cm 2. Since, in the last decade, the use of intentionally strained heterostructures has greatly enhanced the performance of electrical and electro-optical semiconductor, a particular attention will be devoted to intentionally strained superlattices. First the effect of strain on the band lineups alignments in strained heterostructures will be discussed deeply. Then the attention will be focused on to review the most important results obtained by several groups in the characterization of semiconductor heterostructures using the following structural SR techniques: (i) X-ray absorption-based techniques such as EXAFS, polarization-dependent EXAFS, surface EXAFS and NEXAFS (or XANES); (ii) X-ray diffraction-based techniques such as high-resolution XRD, grazing incidence XRD, XRD reciprocal space maps, X-ray standing waves and diffraction anomalous fine structure (DAFS); (iii

  1. Rapid Identification and Characterization of Francisella by Molecular Biology and Other Techniques

    PubMed Central

    Lai, Xin-He; Zhao, Long-Fei; Chen, Xiao-Ming; Ren, Yi

    2016-01-01

    Francisella tularensis is the causative pathogen of tularemia and a Tier 1 bioterror agent on the CDC list. Considering the fact that some subpopulation of the F. tularensis strains is more virulent, more significantly associated with mortality, and therefore poses more threat to humans, rapid identification and characterization of this subpopulation strains is of invaluable importance. This review summarizes the up-to-date developments of assays for mainly detecting and characterizing F. tularensis and a touch of caveats of some of the assays. PMID:27335619

  2. Development of Reservoir Characterization Techniques and Production Models for Exploiting Naturally Fractured Reservoirs

    SciTech Connect

    Wiggins, Michael L.; Brown, Raymon L.; Civan, Faruk; Hughes, Richard G.

    2003-02-11

    This research was directed toward developing a systematic reservoir characterization methodology which can be used by the petroleum industry to implement infill drilling programs and/or enhanced oil recovery projects in naturally fractured reservoir systems in an environmentally safe and cost effective manner. It was anticipated that the results of this research program will provide geoscientists and engineers with a systematic procedure for properly characterizing a fractured reservoir system and a reservoir/horizontal wellbore simulator model which can be used to select well locations and an effective EOR process to optimize the recovery of the oil and gas reserves from such complex reservoir systems.

  3. Quantum annealing correction with minor embedding

    NASA Astrophysics Data System (ADS)

    Vinci, Walter; Albash, Tameem; Paz-Silva, Gerardo; Hen, Itay; Lidar, Daniel A.

    2015-10-01

    Quantum annealing provides a promising route for the development of quantum optimization devices, but the usefulness of such devices will be limited in part by the range of implementable problems as dictated by hardware constraints. To overcome constraints imposed by restricted connectivity between qubits, a larger set of interactions can be approximated using minor embedding techniques whereby several physical qubits are used to represent a single logical qubit. However, minor embedding introduces new types of errors due to its approximate nature. We introduce and study quantum annealing correction schemes designed to improve the performance of quantum annealers in conjunction with minor embedding, thus leading to a hybrid scheme defined over an encoded graph. We argue that this scheme can be efficiently decoded using an energy minimization technique provided the density of errors does not exceed the per-site percolation threshold of the encoded graph. We test the hybrid scheme using a D-Wave Two processor on problems for which the encoded graph is a two-level grid and the Ising model is known to be NP-hard. The problems we consider are frustrated Ising model problem instances with "planted" (a priori known) solutions. Applied in conjunction with optimized energy penalties and decoding techniques, we find that this approach enables the quantum annealer to solve minor embedded instances with significantly higher success probability than it would without error correction. Our work demonstrates that quantum annealing correction can and should be used to improve the robustness of quantum annealing not only for natively embeddable problems but also when minor embedding is used to extend the connectivity of physical devices.

  4. Characterization of high resolution MR images reconstructed by a GRAPPA based parallel technique

    NASA Astrophysics Data System (ADS)

    Banerjee, Suchandrima; Majumdar, Sharmila

    2006-03-01

    This work implemented an auto-calibrating parallel imaging technique and applied it to in vivo magnetic resonance imaging (MRI) of trabecular bone micro-architecture. A Generalized auto-calibrating partially parallel acquisition (GRAPPA) based reconstruction technique using modified robust data fitting was developed. The MR data was acquired with an eight channel phased array receiver on three normal volunteers on a General Electric 3 Tesla scanner. Microstructures comprising the trabecular bone architecture are of the order of 100 microns and hence their depiction requires very high imaging resolution. This work examined the effects of GRAPPA based parallel imaging on signal and noise characteristics and effective spatial resolution in high resolution (HR) images, for the range of undersampling or reduction factors 2-4. Additionally quantitative analysis was performed to obtain structural measures of trabecular bone from the images. Image quality in terms of contrast and depiction of structures was maintained in parallel images for reduction factors up to 3. Comparison between regular and parallel images suggested similar spatial resolution for both. However differences in noise characteristics in parallel images compared to regular images affected the threshholding based quantification. This suggested that GRAPPA based parallel images might require different analysis techniques. In conclusion, the study showed the feasibility of using parallel imaging techniques in HR-MRI of trabecular bone, although quantification strategies will have to be further investigated. Reduction of acquisition time using parallel techniques can improve the clinical feasibility of MRI of trabecular bone for prognosis and staging of the skeletal disorder osteoporosis.

  5. Synthesis and characterization of nanoporous silica film via non-surfactant template sol-gel technique

    NASA Astrophysics Data System (ADS)

    Al-Harbi, T.; Al-Hazmi, F.; Mahmoud, Waleed E.

    2012-10-01

    Nanoporous silicon dioxide has received growing interests owing to their peculiar application potentials in conservation and storage energy. Therefore, the development of novel and simple techniques is required for raising these nanoporous materials to industrial level. In this research, we report novel strategy for the synthesis of nanoporous SiO2 via non-surfactant template sol-gel technique for the first time. The morphology and structure of the as prepared and annealed nanoporous silica films were studied using X-ray diffraction, scanning electron microscope, Fourier transform infrared spectroscopy and nitrogen absorption/desorption technique. The results showed that highly order nanoporous silica film has been obtained at annealing temperature 600 °C with average diameter 5.1 nm and average pore volume 3.6 cm3 g-1.

  6. Geostatistical characterization of the soil of Aguascalientes, México, by using spatial estimation techniques.

    PubMed

    Magdaleno-Márquez, Ricardo; de la Luz Pérez-Rea, María; Castaño, Víctor M

    2016-01-01

    Four spatial estimation techniques available in commercial computational packages are evaluated and compared, namely: regularized splines interpolation, tension splines interpolation, inverse distance weighted interpolation, and ordinary Kriging estimation, in order to establish the best representation for the shallow stratigraphic configuration in the city of Aguascalientes, in Central Mexico. Data from 478 sample points along with the software ArcGIS (Environmental Systems Research Institute, Inc. (ESRI), ArcGIS, ver. 9.3, Redlands, California 2008) to calculate the spatial estimates. Each technique was evaluated based on the root mean square error, calculated from a validation between the generated estimates and measured data from 64 sample points which were not used in the spatial estimation process. The present study shows that, for the estimation of the hard-soil layer, ordinary Kriging offered the best performance among the evaluated techniques. PMID:27386362

  7. Advanced, time-resolved imaging techniques for electron-beam characterizations

    SciTech Connect

    Lumpkin, A.H.

    1990-01-01

    Several unique time-resolved imaging techniques have been developed to address radio frequency (RF)-linac generated electron beams and the free-electron lasers (FEL) driven by such systems. The time structures of these beams involve a series of micropulses with 10 to 15-ps duration, separated by tens of nanoseconds. Mechanisms to convert the e-beam information to optical radiation include optical transition radiation (OTR), Cherenkov radiation, spontaneous emission radiation (SER), and the FEL mechanism itself. The use of gated, intensified television cameras and synchroscan and dual-sweep streak cameras to time-resolve these signals has greatly enhanced the power of these techniques. A brief review of the less familiar conversion mechanisms and electro-optic techniques is followed by a series of specific experimental examples from the RF linac FEL facilities at Los Alamos and Boeing (Seattle, WA). 23 refs., 35 figs., 3 tabs.

  8. Thermal characterization of starch-water system by photopyroelectric technique and adiabatic scanning calorimetry

    NASA Astrophysics Data System (ADS)

    Cruz-Orea, A.; Bentefour, E. H.; Jamée, P.; Chirtoc, M.; Glorieux, C.; Pitsi, G.; Thoen, J.

    2003-01-01

    Starch is one of the most important carbohydrate sources in human nutrition. For the thermal analysis of starch, techniques such as differential scanning calorimetry have been extensively used. As an alternative, we have applied a photopyroelectric (PPE) configuration and adiabatic scanning calorimetry (ASC) to study the thermal properties of starch-water systems. For this study we used nixtamalized corn flour and potato starch with different quantities of distilled water, in order to obtain samples with different moisture content. By using PPE and ASC methods we have measured, for each technique separately, the heat capacity by unit volume (ρcp) at room temperature for a corn flour sample at 90% moisture. The obtained values agree within experimental uncertainty. By using these techniques we also studied the thermal behavior of potato starch, at 80% moisture, in the temperature range where phase transitions occur. In this case the PPE signal phase could be used as a sensitive and versatile monitor for phase transitions.

  9. Embedded Doppler system for industrial in-line rheometry.

    PubMed

    Ricci, Stefano; Liard, Maxime; Birkhofer, Beat; Lootens, Didier; Bruhwiler, Armin; Tortoli, Piero

    2012-07-01

    Rheological fluid behavior characterization is crucial for the industrial production of cosmetics, food, pharmaceutics, adhesive, sealants, etc. For example, the measurement of specific rheological features at every step of the production chain is critical for product quality control. Such measurements are often limited to laboratory tests on product specimens because of technical difficulties. In this work, we present an embedded system suitable for in-line rheometric evaluation of highly filled polyurethane-based adhesives. This system includes an ultrasound front-end and a digital signal processing section integrated in a low-cost field-programmable gate array. The system measures the real-time velocity profile developed in the pipe by the fluid, employing a Doppler multigate technique. The high-resolution velocity profile, combined with a pressure drop measurement, allows an accurate evaluation of the flow consistency index, K, and the flow behavior index, n, of the interrogated fluid. PMID:22828835

  10. Advanced atomic force microscopy techniques for characterizing the properties of cellulosic nanomaterials

    NASA Astrophysics Data System (ADS)

    Wagner, Ryan Bradley

    The measurement of nanomechanical properties is of great interest to science and industry. Key to progress in this area is the development of new techniques and analysis methods to identify, measure, and quantify these properties. In this dissertation, new data analysis methods and experimental techniques for measuring nanomechanical properties with the atomic force microscope (AFM) are considered. These techniques are then applied to the study of cellulose nanoparticles, an abundant, plant derived nanomaterial. Quantifying uncertainty is a prerequisite for the manufacture of reliable nano-engineered materials and products. However, rigorous uncertainty quantification is rarely applied for material property measurements with the AFM. A framework is presented to ascribe uncertainty to local nanomechanical properties of any nanoparticle or surface measured with the AFM by taking into account the main uncertainty sources inherent in such measurements. This method is demonstrated by quantifying uncertainty in force displacement AFM based measurements of the transverse elastic modulus of tunicate cellulose nanocrystals. Next, a more comprehensive study of different types of cellulose nanoparticles is undertaken with contact resonance (CR) AFM. CR-AFM is a dynamic AFM technique that exploits the resonance frequency of the AFM cantilever while it is permanent contact with the sample surface to predict nanomechanical properties. This technique offers improved measurement sensitivity over static AFM methods for some material systems. The effects of cellulose source material and processing technique on the properties of cellulose nanoparticles are compared. Finally, dynamic AFM cantilever vibration shapes are studied. Many AFM modes exploit the dynamic response of a cantilever in permanent contact with a sample to extract local material properties. A common challenge to these modes is that they assume a certain shape of cantilever vibration, which is not accessible in

  11. CHARACTERIZATION OF FUNGI FROM HYPERSALINE ENVIRONMENTS OF SOLAR SALTERNS USING MORPHOLOGICAL AND MOLECULAR TECHNIQUES

    EPA Science Inventory

    The Cabo Rojo Solar Salterns located on the southwest coast of Puerto Rico are composed of two main ecosystems (i.e., salt ponds and microbial mats). Even though these locations are characterized by high solar radiation (mean light intensity of 39 mol photons m-2d-1) they harbor ...

  12. Nuclear Microscopy for Air-Pollutant Characterization and Its Advantages over Traditional Techniques

    NASA Astrophysics Data System (ADS)

    Ram, S. S.; Kumar, R. V.; Chaudhuri, P.; Chanda, S.; Santra, S. C.; Deary, M.; Sudarshan, M.; Chakraborty, A.

    2014-03-01

    In the present study we establish the use of the proton induced X-ray emission (PIXE) technique coupled with Rutherford backscattering as a sensitive technique for air-pollution monitoring. Several elements such as Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, and As were detected in the ppm level of concentration. Comparisons show the advantages of micro-PIXE over scanning microscope-based energy-dispersive X-ray spectrometry (SEM-EDX) and energy-dispersive X-ray fluorescence spectrometry (EDXRF).

  13. Micro-structural characterization of materials using synchrotron hard X-ray imaging techniques

    SciTech Connect

    Agrawal, Ashish Singh, Balwant; Kashyap, Yogesh; Sarkar, P. S.; Shukla, Mayank; Sinha, Amar

    2015-06-24

    X-ray imaging has been an important tool to study the materials microstructure with the laboratory based sources however the advent of third generation synchrotron sources has introduced new concepts in X-ray imaging such as phase contrast imaging, micro-tomography, fluorescence imaging and diffraction enhance imaging. These techniques are being used to provide information of materials about their density distribution, porosity, geometrical and morphological characteristics at sub-micron scalewith improved contrast. This paper discusses the development of various imaging techniques at synchrotron based imaging beamline Indus-2 and few recent experiments carried out at this facility.

  14. INVESTIGATING ULTRASONIC DIFFRACTION GRATING SPECTROSCOPY AND REFLECTION TECHNIQUES FOR CHARACTERIZING SLURRY PROPERTIES

    EPA Science Inventory

    The objectives of the project are to investigate the use of (1) ultrasonic diffraction grating spectroscopy (UDGS) for measuring the particle size of a slurry and (2) shear wave reflection techniques to measure the viscosity of a slurry. For the first topic, the basic principle...

  15. Characterization of Electrode Materials for Lithium Ion and Sodium Ion Batteries using Synchrotron Radiation Techniques

    SciTech Connect

    Mehta, Apurva; Stanford Synchrotron Radiation Lightsource; Doeff, Marca M.; Chen, Guoying; Cabana, Jordi; Richardson, Thomas J.; Mehta, Apurva; Shirpour, Mona; Duncan, Hugues; Kim, Chunjoong; Kam, Kinson C.; Conry, Thomas

    2013-04-30

    We describe the use of synchrotron X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) techniques to probe details of intercalation/deintercalation processes in electrode materials for Li ion and Na ion batteries. Both in situ and ex situ experiments are used to understand structural behavior relevant to the operation of devices.

  16. 11-Isopropylcryptolepine: A novel alkaloid isolated from cryptolepis sanguinolenta characterized using submicro NMR techniques

    PubMed

    Hadden; Sharaf; Guido; Robins; Tackie; Phoebe; Schiff; Martin

    1999-02-01

    A new alkaloid has been isolated from extracts of the West African plant Cryptolepis sanguinolenta and identified by submicro NMR techniques as 11-isopropylcryptolepine (1). The unusual incorporation of the isopropyl group at the 11-position of the indolo[3,2-b]quinoline nucleus is suggestive of a mixed biosynthetic origin for the alkaloid. PMID:10075749

  17. Advance development of a technique for characterizing the thermomechanical properties of thermally stable polymers

    NASA Technical Reports Server (NTRS)

    Gillham, J. K.; Stadnicki, S. J.; Hazony, Y.

    1974-01-01

    The torsional braid experiment has been interfaced with a centralized hierarchical computing system for data acquisition and data processing. Such a system, when matched by the appropriate upgrading of the monitoring techniques, provides high resolution thermomechanical spectra of rigidity and damping, and their derivatives with respect to temperature.

  18. A methodological intercomparison of topographic survey techniques for characterizing wadeable streams and rivers

    NASA Astrophysics Data System (ADS)

    Bangen, Sara G.; Wheaton, Joseph M.; Bouwes, Nicolaas; Bouwes, Boyd; Jordan, Chris

    2014-02-01

    Fine-scale (submeter) resolution digital elevation models (DEMs) created from high precision (subcentimeter) instruments (e.g., total station, rtkGPS, and laser scanning) have become ubiquitous in the field of fluvial geomorphology. They permit a diverse range of spatially explicit analyses including hydraulic modeling, habitat modeling, and geomorphic change detection. While previous studies have assessed the quality of specific topographic survey methods at individual sites or across a limited number of sites, an intercomparison of survey technologies across a diverse range of wadeable streams could help clarify which techniques are feasible, as well as which work best under what circumstances and for what purposes. Although a wealth of existing studies and protocols explain how to undertake each individual technique, in this study we seek to provide guidance on what techniques to use in which circumstances. We quantified the relative quality and the amount of effort spent collecting data to derive bare earth topography from an array of ground-based and airborne survey techniques. We used topographic survey data collected over the summer of 2010 from six sample reaches of varying complexity in the Lemhi River basin, Idaho, USA. We attempted to conduct complete, replicate surveys at each site using total station (TS), real-time kinematic (rtk) GPS, discrete return terrestrial laser scanner (TLS), and airborne LiDaR surveys (ALS). We evaluated the precision and accuracy of derived bare earth DEMs relative to the higher precision total station point data. Discrepancies between pairwise techniques were calculated using propagated DEM errors thresholded at a 95% confidence interval. Mean discrepancies between total station and rtkGPS DEMs were relatively low (≤ 0.05 m), yet TS data collection time was up to 2.4 times longer than rtkGPS. The ALS DEMs had lower accuracy than TS or rtkGPS DEMs, but the aerial coverage and floodplain context of the ALS data set was

  19. Mechanical characterization of thin film structures using a laser spallation technique

    NASA Astrophysics Data System (ADS)

    Wu, Jianxin

    The laser spallation technique has been developed to measure the interface strength between different materials, especially thin film structures. In this work, it is refined and applied to various material systems. With these advances, the laser spallation technique is now fully mature for applications not only to measurement of material interface strength, but also to the study of laser-material interaction, dynamic fracture mechanics, as well as to the measurement of material bulk properties. In the first part of this work, the laser spallation technique was examined quantitatively for signal processing and stress wavefield recovery. It is shown that the short time Fourier transformation is another appropriate means for recovering the free surface displacement from the acquired optical signal. Two methods have been chosen to recover the stress field inside the sample. When the displacement of the coating's free surface is recorded directly, it is convenient to use a special finite difference strategy. When the free surface displacement is recorded on the bare substrate surface, it is more convenient to use the finite element method to calculate the interface strength. The application work includes several topics. The first one was the evaluation of the effect of substrate orientation and deposition mode on the interface strength of Nb-sapphire interfaces. The interface strength is higher for the sapphire substrate with prismatic orientation, and RF deposition mode yields higher interface strength than the DC mode. The second application estimated the effect of substrate roughness on the interface strength of Nb-alumina system. The effect of chemical composition of thin films on the interface strength was also investigated. The final application investigated the dynamic fracture mechanics of thin film structures. The purpose of this chapter is to clarify the controversial topic regarding the limit speed of bimaterial interface crack propagation. We were successful

  20. Synchrotron Techniques for in-situ Characterization of Hydrogen Storage Materials and Their Applications to NaAlH4

    NASA Astrophysics Data System (ADS)

    Gao, Yan; Rijssenbeek, Job T.; Morris, William; Heward, William; Smentkowski, Vincent; Hanson, Jon; Wang, Xianqin; Chupas, Peter; Lee, Peter; Srinivasan, Sesha S.; Jensen, Craig M.

    2004-03-01

    Several synchrotron techniques, including time-resolved powder diffraction (XRD), X-ray Absorption Fine Structure (XAFS) and Rapid Acquisition Pair-Distribution Function (RA-PDF) analysis, for in-situ characterization of hydrogen storage materials will be discussed. Studies on NaAlH4 will be used as an example but these techniques are useful for hydrogen storage materials in general. We will demonstrate the capabilities of powder diffraction with high speed data acquisition (3 seconds per pattern) and under high-pressure (2000 psi) recently achieved using synchrotron sources, which are of importance for studying fast kinetics and high-pressure charging reactions. The superior angular resolution of synchrotron radiation allows the detection of subtle changes in crystallite size (such as the Al phase in the case of NaAlH_4) during cycling of these materials, which often is not possible with in-house sources. We will also describe in-situ XAFS at high-temperatures for studying the oxidation state and chemical environment of low level catalysts (such as Ti) commonly used in these materials. Finally, we will discuss the time-resolved RA-PDF technique, which follows the change of interatomic distances in the course of phase transformation. These techniques are complementary and each probes the microstructure of these materials from a unique perspective; the combined use of these techniques will open an unprecedented opportunity for improving our understanding of hydrogen storage materials.

  1. Novel elastomers, characterization techniques, and improvements in the mechanical properties of some thermoplastic biodegradable polymers and their nanocomposites

    NASA Astrophysics Data System (ADS)

    Hassan, Mohamed Korany Ibrahim

    This work focused in its first part on the preparation and characterization of novel elastomers based on poly(tetrahydrofuran) (PTHF) networks. Elastomers were prepared by a hydrolysis-condensation reaction which has been followed up by FTIR spectroscopic techniques. The elastomers thus obtained were studied with regard to their equilibrium swelling in toluene at 25°C, and their stress-strain isotherms in elongation. For some of the samples, high elongations seemed to bring about highly desirable strain-induced crystallization, as evidenced by upturns in the modulus. Swelling of these samples with increasing amounts of the non-volatile diluent dibutyl phthalate caused the upturns to gradually disappear. The second part of this work was focused on diversifying the newly developed sound wave propagation technique to characterize elastomeric polymer networks. The technique was applied to characterize polybutadiene (PBD) networks. The speed of wave propagation in PBD networks was found to be strongly dependent on the network structural parameters such as average molecular weight of chain between crosslinks and entanglement molecular weight. Also, for the swollen networks, pulse speeds decreased with increase in degree of swelling. Upturns due to strain-induced crystallization at higher elongations were clearly evidenced in the pulse speeds. The third part of this work presented improvements in the mechanical properties of thermoplastic biodegradable poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (Nodax(TM)) using a pre-orientation technique. This simple approach involved heating the polymer film to a temperature above its glass transition temperature, stretching it to the desired extension (%), and then quenching it to room temperature while in the stretched state. As expected, pre-orientation resulted in substantial improvements in the mechanical properties of the films. The pre-oriented films had higher values of the modulus, toughness, yield stress, and tensile

  2. Structural characterization of MG and pre-MG states of proteins by MD simulations, NMR, and other techniques.

    PubMed

    Naiyer, Abdullah; Hassan, Md Imtaiyaz; Islam, Asimul; Sundd, Monica; Ahmad, Faizan

    2015-01-01

    Almost all proteins fold via a number of partially structured intermediates such as molten globule (MG) and pre-molten globule states. Understanding the structure of these intermediates at atomic level is often a challenge, as these states are observed under extreme conditions of pH, temperature, and chemical denaturants. Furthermore, several other processes such as chemical modification, site-directed mutagenesis (or point mutation), and cleavage of covalent bond of natural proteins often lead to MG like partially unfolded conformation. However, the dynamic nature of proteins in these states makes them unsuitable for most structure determination at atomic level. Intermediate states studied so far have been characterized mostly by circular dichroism, fluorescence, viscosity, dynamic light scattering measurements, dye binding, infrared techniques, molecular dynamics simulations, etc. There is a limited amount of structural data available on these intermediate states by nuclear magnetic resonance (NMR) and hence there is a need to characterize these states at the molecular level. In this review, we present characterization of equilibrium intermediates by biophysical techniques with special reference to NMR. PMID:25586676

  3. Development of Reservoir Characterization Techniques and Production Models for Exploiting Naturally Fractured Reservoirs

    SciTech Connect

    Wiggins, Michael L; Brown, Raymon L.; Civan, Faruk; Hughes, Richard G.

    2002-10-08

    During this reporting period, research was continued on characterizing and modeling the behavior of naturally fractured reservoir systems. This report proposed a model to relate the seismic response to production data to determine crack spacing and aperture, provided details of tests of proposed models to obtain fracture properties from conventional well logs with actual field data, and verification of the naturally fractured reservoir simulator developed in this project.

  4. New techniques for the characterization of refuse-derived fuels and solid recovered fuels.

    PubMed

    Rotter, Vera Susanne; Lehmann, Annekatrin; Marzi, Thomas; Möhle, Edda; Schingnitz, Daniel; Hoffmann, Gaston

    2011-02-01

    Solid recovered fuel (SRF) today refers to a waste-derived fuel meeting defined quality specifications, in terms of both origin (produced from non-hazardous waste) and levels of certain fuel properties. Refuse-derived fuel (RDF) nowadays is more used for unspecified waste after a basic processing to increase the calorific value and therefore this term usually refers to the segregated, high calorific fraction of municipal solid waste (MSW), commercial or industrial wastes. In comparison with conventional fuels, both types of secondary fuel show waste of inherently varying quality and an increased level of waste-specific contaminants.The transition from RDF to SRF in the emerging national and European market requires a quality assurance system with defined quality parameters and analytical methods to ensure reliable fuel characterization. However, due to the quality requirements for RDF and SRF, the current standardized analysis methods often do not meet these practical demands. Fast test methods, which minimize personnel, financial and time efforts and which are applicable for producers as well as users can be an important supporting tool for RDF- and SRF-characterization. Currently, a fast test system based on incineration and correlation analyses which enable the determination of relevant fuel parameters is under development. Fast test methods are not aimed at replacing current standardized test methods, but have to be considered as practical supporting tools for the characterization of RDF and SRF. PMID:20392788

  5. Constraint Embedding for Multibody System Dynamics

    NASA Technical Reports Server (NTRS)

    Jain, Abhinandan

    2009-01-01

    This paper describes a constraint embedding approach for the handling of local closure constraints in multibody system dynamics. The approach uses spatial operator techniques to eliminate local-loop constraints from the system and effectively convert the system into tree-topology systems. This approach allows the direct derivation of recursive O(N) techniques for solving the system dynamics and avoiding the expensive steps that would otherwise be required for handling the closedchain dynamics. The approach is very effective for systems where the constraints are confined to small-subgraphs within the system topology. The paper provides background on the spatial operator O(N) algorithms, the extensions for handling embedded constraints, and concludes with some examples of such constraints.

  6. Development and characterization of an automatic technique for the alignment of fMRI time series.

    PubMed

    Ciulla, C; Deek, F P

    2001-01-01

    An automatic technique for the registration of fMRI time series has been developed, implemented and tested. The method assumes the human brain to be a rigid body and computes a head coordinate system on the basis of three reference points that lies on the directions corresponding to two of the principal axes of the volume at the intersections with the head boundary. Such directions are found computing the eigenvectors of the symmetric inertia matrix of the image. The inertia components were extracted weighting pixels' coordinates with their intensity values. The three reference points were found in the same position, relative to the head, in both the test and the reference images. The technique has been tested using T2*-weighted Magnetic Resonance (MR) images in which known rigid body transformations have been applied. The results obtained indicate that the method offers subvoxel accuracy in correcting misalignment among time points in fMRI time series. PMID:11599532

  7. Characterizing Si:P quantum dot qubits with spin resonance techniques.

    PubMed

    Wang, Yu; Chen, Chin-Yi; Klimeck, Gerhard; Simmons, Michelle Y; Rahman, Rajib

    2016-01-01

    Quantum dots patterned by atomically precise placement of phosphorus donors in single crystal silicon have long spin lifetimes, advantages in addressability, large exchange tunability, and are readily available few-electron systems. To be utilized as quantum bits, it is important to non-invasively characterise these donor quantum dots post fabrication and extract the number of bound electron and nuclear spins as well as their locations. Here, we propose a metrology technique based on electron spin resonance (ESR) measurements with the on-chip circuitry already needed for qubit manipulation to obtain atomic scale information about donor quantum dots and their spin configurations. Using atomistic tight-binding technique and Hartree self-consistent field approximation, we show that the ESR transition frequencies are directly related to the number of donors, electrons, and their locations through the electron-nuclear hyperfine interaction. PMID:27550779

  8. Dual-sensor technique for characterization of carrier lifetime decay transients in semiconductors

    SciTech Connect

    Ahrenkiel, R. K.; Johnston, S. W.; Kuciauskas, D.; Tynan, Jerry

    2014-12-07

    This work addresses the frequent discrepancy between transient photoconductive (PC) decay and transient photoluminescence (PL) decay. With this dual- sensor technique, one measures the transient PC and PL decay simultaneously with the same incident light pulse, removing injection-level uncertainty. Photoconductive decay measures the transient photoconductivity, Δσ(t). PCD senses carriers released from shallow traps as well as the photo-generated electron-hole pairs. In addition, variations in carrier mobility with injection level (and time) contribute to the decay time. PL decay senses only electron-hole recombination via photon emission. Theory and experiment will show that the time dependence of the two techniques can be quite different at high injection.

  9. An Approximate Numerical Technique for Characterizing Optical Pulse Propagation in Inhomogeneous Biological Tissue

    PubMed Central

    Handapangoda, Chintha C.; Premaratne, Malin

    2008-01-01

    An approximate numerical technique for modeling optical pulse propagation through weakly scattering biological tissue is developed by solving the photon transport equation in biological tissue that includes varying refractive index and varying scattering/absorption coefficients. The proposed technique involves first tracing the ray paths defined by the refractive index profile of the medium by solving the eikonal equation using a Runge-Kutta integration algorithm. The photon transport equation is solved only along these ray paths, minimizing the overall computational burden of the resulting algorithm. The main advantage of the current algorithm is that it enables to discretise the pulse propagation space adaptively by taking optical depth into account. Therefore, computational efficiency can be increased without compromising the accuracy of the algorithm. PMID:18317526

  10. Quantitative characterization of lignocellulosic biomass using surrogate mixtures and multivariate techniques.

    PubMed

    Krasznai, Daniel J; Champagne, Pascale; Cunningham, Michael F

    2012-04-01

    PLS regression models were developed using mixtures of cellulose, xylan, and lignin in a ternary mixture experimental design for multivariate model calibration. Mid-infrared spectra of these representative samples were recorded using Attenuated Total Reflectance (ATR) Fourier Transform Infrared (FT-IR) spectroscopy and regressed against their known composition using Partial Least Squares (PLSs) multivariate techniques. The regression models were cross-validated and then used to predict the unknown compositions of two Arabidopsis cultivars, B10 and C10. The effect of various data preprocessing techniques on the final predictive ability of the PLS regression models was also evaluated. The predicted compositions of B10 and C10 by the PLS regression model after second derivative data preprocessing were similar to the results provided by a third-party analysis. This study suggests that mixture designs could be used as calibration standards in PLS regression for the compositional analysis of lignocellulosic materials if the infrared data is appropriately preprocessed. PMID:22342087

  11. Techniques for improving the Si-SiO2 interface characterization

    NASA Technical Reports Server (NTRS)

    Sher, A.; Hoffman, H. J.; Su, P.; Tsuo, Y. H.

    1983-01-01

    The two techniques which have provided most of the information on interface states in MIS-C (metal-insulator-semiconductor-capacitor) structures are the 'quasi-static method' and the 'conductance method'. Sher et al. (1979) and Su et al. (1980) have suggested a number of improvements concerning these methods. The present investigation has the objective to extend the earlier results and to offer a new tentative interpretation of the data. A critical review is conducted of the data collection and reduction techniques for the quasi-static method, taking into account the sample, the quasi-static capacitance, and the surface potential. In connection with a discussion of the conductance method, attention is given to parallel conductance and capacitance measurements, interface-state densities, time constants, and measurements on a (110) surface orientation.

  12. Characterizing Si:P quantum dot qubits with spin resonance techniques

    PubMed Central

    Wang, Yu; Chen, Chin-Yi; Klimeck, Gerhard; Simmons, Michelle Y.; Rahman, Rajib

    2016-01-01

    Quantum dots patterned by atomically precise placement of phosphorus donors in single crystal silicon have long spin lifetimes, advantages in addressability, large exchange tunability, and are readily available few-electron systems. To be utilized as quantum bits, it is important to non-invasively characterise these donor quantum dots post fabrication and extract the number of bound electron and nuclear spins as well as their locations. Here, we propose a metrology technique based on electron spin resonance (ESR) measurements with the on-chip circuitry already needed for qubit manipulation to obtain atomic scale information about donor quantum dots and their spin configurations. Using atomistic tight-binding technique and Hartree self-consistent field approximation, we show that the ESR transition frequencies are directly related to the number of donors, electrons, and their locations through the electron-nuclear hyperfine interaction. PMID:27550779

  13. Growth and characterization of 4-chloro-3-nitrobenzophenone single crystals using vertical Bridgman technique

    SciTech Connect

    Aravinth, K. Babu, G. Anandha Ramasamy, P.

    2014-04-24

    4-chloro-3-nitrobenzophenone (4C3N) has been grown by using vertical Bridgman technique. The grown crystal was confirmed by Powder X-ray diffraction analysis. The crystalline perfection of the grown crystal was examined by high-resolution X-ray diffraction study. The fluorescence spectra of grown 4C3N single crystals exhibit emission peak at 575 nm. The micro hardness measurements were used to analyze the mechanical property of the grown crystal.

  14. Preparation and Characterization of SnO Nanoplatelets by Microwave Innovative Technique

    SciTech Connect

    Krishnakumar, T.; Perumal, K.; Jayaprakash, R.; Pinna, Nicola

    2008-04-23

    Tin oxide (SnO) nanoplatelets have been synthesized by a Microwave innovative technique with an operating frequency of 2.45 GHz in just few minutes. The crystalline size and structure was evaluated from XRD pattern. The SEM and TEM analysis showed the single crystal platelets together with many small particles attached to its surface. The FT-IR and the electrical conductivity of the samples have also been investigated.

  15. Assessment of techniques for characterizing the surface quality of ground silicon nitride

    SciTech Connect

    Zanoria, E.S.; Watkins, T.R.; Breder, K.; Riester, L.; Bashkansky, M.; Reintjes, J.; Blau, P.J.; Sun, J.G.; Ellingson, W.A.

    1998-08-01

    This study evaluates techniques used to detect and quantify the extent of surface and subsurface damage in ground silicon nitride. Specimens of two differently ground surfaces of a hot isostatically pressed (HIP) silicon nitride, commercially designated as GS-44, were subjected to six types of analyses, namely mechanical stylus profiling, atomic force microscopy, point-counting analysis of fragmentation pits, laser-light scattering, optical gating, and grazing incidence x-ray diffraction (GIXD). The results of these investigations are compared and discussed. The techniques providing the clearest correlations with grinding conditions were mechanical stylus roughness, fragmentation analysis, and GIXD (residual stress conditions). Those that exhibited some correlation but appear to require more work to develop a reliable evaluation method were laser scattering and optical gating. Atomic force microscopy was useful, but not as a routine investigative tool for quality control in ceramic machining. The techniques that appear to have the most near-term potential for routine use are fragmentation analysis and optical gating. Laser-based optical scattering exhibits potential for routine application, but, more development is needed for its commercialization.

  16. Uniaxial Pre-strain and Free Recovery (UPFR) as a Flexible Technique for Nitinol Characterization

    NASA Astrophysics Data System (ADS)

    Cadelli, A.; Manjeri, R. M.; Sczerzenie, F.; Coda, A.

    2016-03-01

    The measurement of phase transformation temperatures of superelastic (SE) and shape memory (SM) NiTi alloy products and components was studied in this work. The transformation temperatures of a set of twenty different 300 μm NiTi superelastic wires were measured by two well-established and standardized techniques, namely differential scanning calorimetry (DSC) and bend and free recovery (BFR) and then compared with the results from the Uniaxial Pre-Strain and Free Recovery (UPFR) test. UPFR is a tension-based test, whose aim is to overcome the limitations associated with BFR testing. Within this work, a test procedure has been set up and validated. UPFR is found to be the only method showing a very strong correlation with the mechanical properties measured using the standard uniaxial tensile test method for superelastic NiTi alloy. Further, UPFR has been validated as a robust technique for measuring the R-phase and austenitic transformation temperatures in specimens of various sizes, composition, and of different geometries. This technique overcomes the limitations of BFR and DSC which cannot be used for testing products such as 25 μm SM wire, a 50 μm SE strip, and different springs and microsprings for actuation.

  17. Characterization of Ni-Cr alloys using different casting techniques and molds.

    PubMed

    Chen, Wen-Cheng; Teng, Fu-Yuan; Hung, Chun-Cheng

    2014-02-01

    This study differentiated the mechanical properties of nickel-chromium (Ni-Cr) alloys under various casting techniques (different casting molds and casting atmospheres). These techniques were sampled by a sand mold using a centrifugal machine in ambient air (group I) and electromagnetic induction in an automatic argon castimatic casting machine (group II). The specimen casting used a graphite mold by a castimatic casting machine (group III). The characteristics of the Ni-Cr alloys, yield and ultimate tensile strength, bending modulus, microhardness, diffraction phase, grindability, ability to spring back, as well as ground microstructure and pattern under different casting conditions were evaluated. The group III specimens exhibited the highest values in terms of strength, modulus, hardness, and grindability at a grind rate of 500 rpm. Moreover, group III alloys exhibited smaller grain sizes, higher ability to spring back, and greater ductility than those casted by sand investment (groups I and II). The main factor, "casting mold," significantly influenced all mechanical properties. The graphite mold casting of the Ni-Cr dental alloys in a controlled atmosphere argon casting system provided an excellent combination of high mechanical properties and good ability to spring back, and preserved the ductile properties for application in Ni-Cr porcelain-fused system. The results can offer recommendations to assist a prosthetic technician in selecting the appropriate casting techniques to obtain the desired alloy properties. PMID:24411373

  18. Photothermal Techniques Applied to the Thermal Characterization of l-Cysteine Nanofluids

    NASA Astrophysics Data System (ADS)

    Alvarado, E. Maldonado; Ramón-Gallegos, E.; Jiménez Pérez, J. L.; Cruz-Orea, A.; Hernández Rosas, J.

    2013-05-01

    Thermal-diffusivity ( D) and thermal-effusivity ( e) measurements were carried out in l-cysteine nanoliquids l-cysteine in combination with Au nanoparticles and protoporphyrin IX (PpIX) nanofluid) by using thermal lens spectrometry (TLS) and photopyroelectric (PPE) techniques. The TLS technique was used in the two mismatched mode experimental configuration to obtain the thermal-diffusivity of the samples. On the other hand, the sample thermal effusivity ( e) was obtained by using the PPE technique where the temperature variation of a sample, exposed to modulated radiation, is measured with a pyrolectric sensor. From the obtained thermal-diffusivity and thermal-effusivity values, the thermal conductivity and specific heat capacity of the sample were calculated. The obtained thermal parameters were compared with the thermal parameters of water. The results of this study could be applied to the detection of tumors by using the l-cysteine in combination with Au nanoparticles and PpIX nanofluid, called conjugated in this study.

  19. Computer Vision Techniques Applied to Space Object Detect, Track, ID, Characterize

    NASA Astrophysics Data System (ADS)

    Flewelling, B.

    2014-09-01

    Space-based object detection and tracking represents a fundamental step necessary for detailed analysis of space objects. Initial observations of a resident space object (RSO) may result from careful sensor tasking to observe an object with well understood dynamics, or measurements-of-opportunity on an object with poorly understood dynamics. Dim and eccentric objects present a particular challenge which requires more dynamic use of imaging systems. As a result of more stressing data acquisition strategies, advanced techniques for the accurate processing of both point and streaking sources are needed. This paper will focus on two key methods in computer vision used to determine interest points within imagery. The Harris Corner method and the method of Phase Congruency can be used to effectively extract static and streaking point sources and to indicate when apparent motion is present within an observation. The geometric inferences which can be made from the resulting detections will be discussed, including a method to evaluate the localization uncertainty of the extracted detections which is based on the computation of the Hessian of the detector response. Finally a technique which exploits the additional information found in detected streak endpoints to provide a better centroid in the presence of curved streaks is explained and additional applications for the presented techniques are discussed.

  20. Mass Spectrometry as a Powerful Analytical Technique for the Structural Characterization of Synthesized and Natural Products

    NASA Astrophysics Data System (ADS)

    Es-Safi, Nour-Eddine; Essassi, El Mokhtar; Massoui, Mohamed; Banoub, Joseph

    Mass spectrometry is an important tool for the identification and structural elucidation of natural and synthesized compounds. Its high sensitivity and the possibility of coupling liquid chromatography with mass spectrometry detection make it a technique of choice for the investigation of complex mixtures like raw natural extracts. The mass spectrometer is a universal detector that can achieve very high sensitivity and provide information on the molecular mass. More detailed information can be subsequently obtained by resorting to collision-induced dissociation tandem mass spectrometry (CID-MS/MS). In this review, the application of mass spectrometric techniques for the identification of natural and synthetic compounds is presented. The gas-phase fragmentation patterns of a series of four natural flavonoid glycosides, three synthesized benzodiazepines and two synthesized quinoxalinone derivatives were investigated using electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry techniques. Exact accurate masses were measured using a modorate resolution quadrupole orthogonal time-of-flight QqTOF-MS/MS hybrid mass spectrometer instrument. Confirmation of the molecular masses and the chemical structures of the studied compounds were achieved by exploring the gas-phase breakdown routes of the ionized molecules. This was rationalized by conducting low-energy collision CID-MS/MS analyses (product ion- and precursor ion scans) using a conventional quadrupole hexapole-quadrupole (QhQ) tandem mass spectrometer.

  1. Flow characterization of electroconvective micromixer with a nanoporous polymer membrane in-situ fabricated using a laser polymerization technique

    PubMed Central

    Hwang, Sangbeom; Song, Simon

    2015-01-01

    Electroconvection is known to cause strong convective mixing in a microchannel near a nanoporous membrane or a nanochannel in contact with an electrolyte solution due to the external electric field. This study addresses micromixer behavior subject to electroconvection occurring near a nanoporous membrane in-situ fabricated by a laser polymerization technique on a microfluidic chip. We found that the micromixer behavior can be categorized into three regimes. Briefly, the weak electroconvection regime is characterized by weak mixing performance at a low applied voltage and KCl concentration, whereas the strong electroconvection regime has a high mixing performance when the applied voltage and KCl concentration are moderately high. Finally, the incomplete electroconvection regime has an incomplete electric double-layer overlap in the nanopores of the membrane when the electrolyte concentration is very high. The mixing index reached 0.92 in the strong electroconvection regime. The detailed fabrication methods for the micromixer and characterization results are discussed in this paper. PMID:26064195

  2. Characterization of Bond Strength of U-Mo Fuel Plates Using the Laser Shockwave Technique: Capabilities and Preliminary Results

    SciTech Connect

    J. A. Smith; D. L. Cottle; B. H. Rabin

    2013-09-01

    This report summarizes work conducted to-date on the implementation of new laser-based capabilities for characterization of bond strength in nuclear fuel plates, and presents preliminary results obtained from fresh fuel studies on as-fabricated monolithic fuel consisting of uranium-10 wt.% molybdenum alloys clad in 6061 aluminum by hot isostatic pressing. Characterization involves application of two complementary experimental methods, laser-shock testing and laser-ultrasonic imaging, collectively referred to as the Laser Shockwave Technique (LST), that allows the integrity, physical properties and interfacial bond strength in fuel plates to be evaluated. Example characterization results are provided, including measurement of layer thicknesses, elastic properties of the constituents, and the location and nature of generated debonds (including kissing bonds). LST provides spatially localized, non-contacting measurements with minimum specimen preparation, and is ideally suited for applications involving radioactive materials, including irradiated materials. The theoretical principles and experimental approaches employed in characterizing nuclear fuel plates are described, and preliminary bond strength measurement results are discussed, with emphasis on demonstrating the capabilities and limitations of these methods. These preliminary results demonstrate the ability to distinguish bond strength variations between different fuel plates. Although additional development work is necessary to validate and qualify the test methods, these results suggest LST is viable as a method to meet fuel qualification requirements to demonstrate acceptable bonding integrity.

  3. Embedded instrumentation systems architecture

    NASA Astrophysics Data System (ADS)

    Visnevski, Nikita A.

    2007-04-01

    This paper describes the operational concept of the Embedded Instrumentation Systems Architecture (EISA) that is being developed for Test and Evaluation (T&E) applications. The architecture addresses such future T&E requirements as interoperability, flexibility, and non-intrusiveness. These are the ultimate requirements that support continuous T&E objectives. In this paper, we demonstrate that these objectives can be met by decoupling the Embedded Instrumentation (EI) system into an on-board and an off-board component. An on-board component is responsible for sampling, pre-processing, buffering, and transmitting data to the off-board component. The latter is responsible for aggregating, post-processing, and storing test data as well as providing access to the data via a clearly defined interface including such aspects as security, user authentication and access control. The power of the EISA architecture approach is in its inherent ability to support virtual instrumentation as well as enabling interoperability with such important T&E systems as Integrated Network-Enhanced Telemetry (iNET), Test and Training Enabling Architecture (TENA) and other relevant Department of Defense initiatives.

  4. Characterization of soil water content variability and soil texture using GPR groundwave techniques

    SciTech Connect

    Grote, K.; Anger, C.; Kelly, B.; Hubbard, S.; Rubin, Y.

    2010-08-15

    Accurate characterization of near-surface soil water content is vital for guiding agricultural management decisions and for reducing the potential negative environmental impacts of agriculture. Characterizing the near-surface soil water content can be difficult, as this parameter is often both spatially and temporally variable, and obtaining sufficient measurements to describe the heterogeneity can be prohibitively expensive. Understanding the spatial correlation of near-surface soil water content can help optimize data acquisition and improve understanding of the processes controlling soil water content at the field scale. In this study, ground penetrating radar (GPR) methods were used to characterize the spatial correlation of water content in a three acre field as a function of sampling depth, season, vegetation, and soil texture. GPR data were acquired with 450 MHz and 900 MHz antennas, and measurements of the GPR groundwave were used to estimate soil water content at four different times. Additional water content estimates were obtained using time domain reflectometry measurements, and soil texture measurements were also acquired. Variograms were calculated for each set of measurements, and comparison of these variograms showed that the horizontal spatial correlation was greater for deeper water content measurements than for shallower measurements. Precipitation and irrigation were both shown to increase the spatial variability of water content, while shallowly-rooted vegetation decreased the variability. Comparison of the variograms of water content and soil texture showed that soil texture generally had greater small-scale spatial correlation than water content, and that the variability of water content in deeper soil layers was more closely correlated to soil texture than were shallower water content measurements. Lastly, cross-variograms of soil texture and water content were calculated, and co-kriging of water content estimates and soil texture

  5. Validation of technique to hyperspectrally characterize the lower atmosphere with limited surface observations

    NASA Astrophysics Data System (ADS)

    Randall, Robb M.; Fiorino, Steven T.; Via, Michelle F.; Downs, Adam D.

    2011-06-01

    This paper demonstrates the capability of AFIT/CDE's Laser Environmental Effects Definition and Reference (LEEDR) model to accurately characterize the meteorological parameters and radiative transfer effects of the atmospheric boundary layer with only surface observations of temperature, pressure, and humidity. The LEEDR model is a fastcalculating, first principles, worldwide surface to 100 km, atmospheric propagation and characterization package. This package enables the creation of profiles of temperature, pressure, water vapor content, optical turbulence, atmospheric particulates and hydrometeors as they relate to line-by-line layer transmission, path and background radiance at wavelengths from the ultraviolet to radio frequencies. Physics-based cloud and precipitation characterizations are coupled with a probability of cloud free line of sight (CFLOS) algorithm for air-to-air, air-to-surface, and surface-to-air (or space) look angles. In general, LEEDR defines the well-mixed atmospheric boundary layer with a worldwide, probabilistic surface climatology based on season and time of day, and then computes the radiative transfer and propagation effects from the vertical profile of meteorological variables. However, the LEEDR user can also directly input surface observations. This research compares the LEEDR vertical profiles created from input surface observations to actual observations from balloon launches. Results are then compared to the LEEDR ExPERT climatological sounding for the same time of day and season. RMSE are calculated and it was found that closer for those profiles made from surface observations than those made from climatological data for the same season and time. Impacts of those differences are shown with a relevant tactical scenario in AFIT/CDE HELEEOS program.

  6. Comparative Analysis of Different Measurement Techniques for MLC Characterization: Preliminary Results

    SciTech Connect

    Larraga-Gutierrez, J. M.; Ballesteros-Zebadua, P.; Garcia-Garduno, O. A.; Martinez-Davalos, A.; Rodriguez-Villafuerte, M.; Moreno-Jimenez, S.; Celis, M. A.

    2008-08-11

    Radiation transmission, leakage and beam penumbra are essential dosimetric parameters related to the commissioning of a multileaf collimation system. This work shows a comparative analysis of commonly used film detectors: X-OMAT V2 and EDR2 radiographic films, and GafChromic EBT registered radiochromic film. The results show that X-OMAT over-estimates radiation leakage and 80-20% beam penumbra. However, according to the reference values reported by the manufacturer for these dosimetric parameters, all three films are adequate for MLC dosimetric characterization, but special care must be taken when X-OMAT V2 film is used due to its low energy photon dependence.

  7. A review of chromatographic characterization techniques for biodiesel and biodiesel blends.

    SciTech Connect

    Pauls, R. E.

    2011-05-01

    This review surveys chromatographic technology that has been applied to the characterization of biodiesel and its blends. Typically, biodiesel consists of fatty acid methyl esters produced by transesterification of plant or animal derived triacylglycerols. Primary attention is given to the determination of trace impurities in biodiesel, such as methanol, glycerol, mono-, di-, and triacylglycerols, and sterol glucosides. The determination of the fatty acid methyl esters, trace impurities in biodiesel, and the determination of the biodiesel content of commercial blends of biodiesel in conventional diesel are also addressed.

  8. Characterization of Weathering Degradation in Aircraft Polymeric Coatings Using NDE Imaging Techniques

    NASA Astrophysics Data System (ADS)

    Kramb, V. A.; Hoffmann, J. P.; Johnson, J. A.

    2003-03-01

    This paper discusses the current progress in a study of nondestructive inspection methods for monitoring epoxy primer coating degradation under simulated weathering conditions. Characterization of the chemical changes in the coating will be conducted using attenuated total reflection (ATR) — Fourier transform infrared (FTIR) spectroscopy and IR microscopy. The nondestructive evaluation (NDE) methods used to monitor the physical degradation of the polymeric coating include: white light interference microscopy (WLIM), nanoindentation, and scanning acoustic microscopy (SAM). The microscopic images obtained using the NDE methods will be correlated with the measured physical and chemical changes. Artificial weathering of the coated samples was conducted using simulated sunlight exposure (Xenon are lamps), combined with heat and humidity.

  9. Squashed embedding of E-R schemas in hypercubes

    SciTech Connect

    Baru, C.K.; Goel, P. )

    1990-04-01

    The authors have been investigating an approach to parallel database processing based on treating entity-relationship (E-R) schema graphs as dataflow graphs. A prerequisite is to find appropriate embeddings of the schema graphs into a processor graph, in this case a hypercube. This paper studies a class of adjacency preserving embeddings that map a node in the schema graph into a subcube (relaxed squashed or RS embeddings) or into adjacent subcubes (relaxed extended squashed or RES embeddings) of a hypercube. The mapping algorithm is motivated by the technique used for state assignment in asynchronous sequential machines. In general, the dimension of the cube required for squashed embedding of a graph is called the weak cubical dimension or WCD of the graph.

  10. A revisit to high-rate mode-II fracture characterization of composites with Kolsky bar techniques.

    SciTech Connect

    Lu, Wei-Yang; Song, Bo; Jin, Huiqing

    2010-03-01

    Nowadays composite materials have been extensively utilized in many military and industrial applications. For example, the newest Boeing 787 uses 50% composite (mostly carbon fiber reinforced plastic) in production. However, the weak delamination strength of fiber reinforced composites, when subjected to external impact such as ballistic impact, has been always potential serious threats to the safety of passengers. Dynamic fracture toughness is a critical indicator of the performance from delamination in such impact events. Quasi-static experimental techniques for fracture toughness have been well developed. For example, end notched flexure (ENF) technique, which is illustrated in Fig. 1, has become a typical method to determined mode-II fracture toughness for composites under quasi-static loading conditions. However, dynamic fracture characterization of composites has been challenging. This has resulted in conflictive and confusing conclusions in regard to strain rate effects on fracture toughness of composites.

  11. Deposition And Characterization of (Ti,Zr)N Thin Films Grown Through PAPVD By The Pulsed Arc Technique

    SciTech Connect

    Marulanda, D. M.; Trujillo, O.; Devia, A.

    2006-12-04

    The Plasma Assisted Physic Vapor Deposition (PAPVD) by the pulsed arc technique has been used for deposition of Titanium Zirconium Nitride (Ti,Zr)N coatings, using a segmented target of TiZr. The deposition was performed in a vacuum chamber with two faced electrodes (target and substrate) using nitrogen as working gas, and a power-controlled source used to produce the arc discharges. Films were deposited on stainless steel 304, and they were characterized using the X-Ray Photoelectron Spectroscopy (XPS), X-Ray Diffraction (XRD), Energy Dispersion Spectroscopy (EDS) and Scanning Probe Microscopy (SPM) techniques. The XRD patterns show different planes in which the film grows. Through SPM, using Atomic Force Microscopy (AFM) and Lateral Force Microscopy (LFM) modes, a nanotribologic study of the thin film was made, determining hardness and friction coefficient.

  12. Raman spectrosopic characterization of human malignant tissues: implications for a percutaneous optical biopsy technique for in-situ tissue diagnosis

    NASA Astrophysics Data System (ADS)

    Redd, Douglas C. B.; Frank, Christopher J.; Feng, Zhe Chuan; Gansler, Ted S.; McCreery, Richard L.

    1994-01-01

    Recent advancements in the technique of Raman spectroscopy now make it possible to achieve rapid, minimally invasive and non-destructive characterization of tissues. In order to evaluate the efficacy of this technique for diagnosis, the Raman spectra of normal and neoplastic human tissues (e.g., breast, kidney, liver and colon) were obtained utilizing visible and near-IR excitation. Normal breast tissue and colon adenocarcinoma showed major Raman features due to the presence of carotenoids and lipids. In breast carcinoma, the features due to lipids were attenuated and as fibrosis (desmoplasia) increased, new spectral features attributable to collagen were observed. Samples of normal and neoplastic liver and kidney show unique spectral differences sufficient to permit tissue differentiation.

  13. Viability of Applying Curie Point Pyrolysis/Gas Chromatography Techniques for Characterization of Ammonium Perchlorate Based Propellants

    SciTech Connect

    BARNETT, JAMES L.; MONTOYA, BERTHA M.

    2002-07-01

    Curie Point pyrolysis-gas chromatography was investigated for use as a tool for characterization of aged ammonium perchlorate based composite propellants (1). Successful application of the technique will support the surveillance program for the Explosives Materials and Subsystems Department (1). Propellant samples were prepared by separating the propellant into reacted (oxidated) and unreacted zones. The experimental design included the determination of system reliability followed by, reproducibility, sample preparation and analysis of pyrolysis products. Polystyrene was used to verify the reliability of the system and showed good reproducibility. Application of the technique showed high variation in the data. Modifications to sample preparation did not enhance the reproducibility. It was determined that the high concentration of ammonium perchlorate in the propellant matrix was compromising the repeatability of the analysis.

  14. Characterization of uranium bearing material using x-ray fluorescence and direct gamma-rays measurement techniques

    NASA Astrophysics Data System (ADS)

    Mujaini, M.; Chankow, N.; Yusoff, M. Z.; Hamid, N. A.

    2016-01-01

    Uranium ore can be easily detected due to various gamma-ray energies emitted from uranium daughters particularly from 238U daughters such as 214Bi, 214Pb and 226Ra. After uranium is extracted from uranium ore, only low energy gamma-rays emitted from 235U may be detected if the detector is placed in close contact to the specimen. In this research, identification and characterization of uranium bearing materials is experimentally investigated using direct measurement of gamma-rays from 235U in combination with the x-ray fluorescence (XRF) technique. Measurement of gamma-rays can be conducted by using high purity germanium (HPGe) detector or cadmium telluride (CdTe) detector while a 57Coradioisotope-excited XRF spectrometer using CdTe detector is used for elemental analysis. The proposed technique was tested with various uranium bearing specimens containing natural, depleted and enriched uranium in both metallic and powder forms.

  15. Structural and optoelectronic characterization of TiO2 films prepared using the sol gel technique

    NASA Astrophysics Data System (ADS)

    Jiménez González, A. E.; Gelover Santiago, S.

    2007-07-01

    TiO2 is a versatile material that makes for fascinating study in any of its several physical forms: monocrystal, polycrystal, powder or thin film. Its enhanced photosensitivity to UV radiation and excellent chemical stability in acidic and aqueous media point to its excellent potential for use in a variety of applications, such as solar cells, electronic devices, chemical sensors and photocatalysts. Of late, thin films of TiO2 have permitted the study of physical and chemical properties that are almost impossible to examine in powders. Using the sol-gel technique, it was possible to prepare TiO2 films, and to specifically modify their characteristic properties by means of annealing treatments. Optical measurements carried out on sol-gel derived films produced results similar to those found in films prepared using the sputtering technique. The use of TiO2 films facilitates the study of the behaviour of crystalline structure, grain size, photoresponse, electrical conductivity in both darkness and light and energy band gap (Eg) as a function of treatment temperature. For the first time, it has been demonstrated that the photoconductivity of TiO2 becomes apparent at a treatment temperature of 350 °C, which means that below this temperature the material is not photosensitive. The photosensitivity (S) of TiO2 films prepared by the sol-gel technique reaches values between 100 and 104, surpassing by more than two orders of magnitude the photosensitivity of TiO2 in powder form. In addition, it was possible to study the surface crystalline structure, where TEM studies clearly revealed both the polycrystalline order and the atomic arrangements of the TiO2 films. Our findings will afford us an opportunity to better study the nature of TiO2 and to enhance its performance with respect to the above-mentioned applications.

  16. Nanomaterial characterization through image treatment, 3D reconstruction and AI techniques

    NASA Astrophysics Data System (ADS)

    Lopez de Uralde Huarte, Juan Jose

    Nanotechnology is not only the science of the future, but it is indeed the science of today. It is used in all sectors, from health to energy, including information technologies and transport. For the present investigation, we have taken carbon black as a use case. This nanomaterial is mixed with a wide variety of materials to improve their properties, like abrasion resistance, tire and plastic wear or tinting strength in pigments. Nowadays, indirect methods of analysis, like oil absorption or nitrogen adsorption are the most common techniques of the nanomaterial industry. These procedures measure the change in the physical state while adding oil and nitrogen. In this way, the superficial area is estimated and related with the properties of the material. Nevertheless, we have chosen to improve the existent direct methods, which consist in analysing microscopy images of nanomaterials. We have made progress in the image processing treatments and in the extracted features. In fact, some of them have overcome the existing features in the literature. In addition, we have applied, for the first time in the literature, machine learning to aggregate categorization. In this way, we identify automatically their morphology, which will determine the final properties of the material that is mixed with. Finally, we have presented an aggregate reconstruction genetic algorithm that, with only two orthogonal images, provides more information than a tomography, which needs a lot of images. To summarize, we have improved the state of the art in direct analysing techniques, allowing in the near future the replacement of the current indirect techniques.

  17. Morphological and Chemical Characterization of Bonding Hydrophobic Adhesive to Dentin Using Ethanol Wet Bonding Technique

    PubMed Central

    Shin, T. Phillip; Yao, Xiaomei; Huenergardt, Robin; Walker, Mary P; Wang, Yong

    2009-01-01

    Objective BisGMA, a widely used component in dentin adhesive has very good mechanical properties after curing, but is relatively hydrophobic and thus, does not adequately infiltrate the water wet demineralized dentin collagen. Developing techniques that would lead to optimum infiltration of the hydrophobic component into the demineralized dentin matrix is very important. The purpose of this study was to evaluate interfacial morphological and chemical characteristics of the resultant adhesive-dentin interface when the ethanol wet bonding technique is used with hydrophobic adhesives. Materials and methods The occlusal one-third of the crown was removed from six unerupted human third molars; a uniform smear layer was created with 600 grit SiC. The dentin surface was etched with 35% phosphoric acid for 15 seconds before applying BisGMA/HEMA model adhesive using either water wet or ethanol wet bonding technique. Five-micro-thick sections of adhesive/dentin interface specimens were cut and stained with Goldner’s trichrome for light microscopy. Companion slabs were analyzed with SEM and micro-Raman spectroscopy. Results The presence of ethanol in the demineralized dentin increased adhesive collagen encapsulation as indicated by trichrome staining. The SEM results confirmed that the ethanol wet bonding improved the quality of the interface. Micro-Raman spectral analysis of the dentin/adhesive interface indicated there was a gradual decrease in penetration of BisGMA component for specimens using water wet bonding, while relatively homogeneous distribution of the hydrophobic BisGMA component was noted in the interface with ethanol wet bonding. Significance Wet bonding with ethanol instead of water permits better BisGMA infiltration improving the quality of interface. We speculate that the higher infiltration of hydrophobic BisGMA and better collagen encapsulation observed from the specimens using ethanol wet bonding would lead to more durable bonds because of improved

  18. Measuring the food environment: a systematic technique for characterizing food stores using display counts.

    PubMed

    Miller, Cassandra; Bodor, J Nicholas; Rose, Donald

    2012-01-01

    Marketing research has documented the influence of in-store characteristics-such as the number and placement of display stands-on consumer purchases of a product. However, little information exists on this topic for key foods of interest to those studying the influence of environmental changes on dietary behavior. This study demonstrates a method for characterizing the food environment by measuring the number of separate displays of fruits, vegetables, and energy-dense snack foods (including chips, candies, and sodas) and their proximity to cash registers in different store types. Observations in New Orleans stores (N = 172) in 2007 and 2008 revealed significantly more displays of energy-dense snacks than of fruits and vegetables within all store types, especially supermarkets. Moreover, supermarkets had an average of 20 displays of energy-dense snacks within 1 meter of their cash registers, yet none of them had even a single display of fruits or vegetables near their cash registers. Measures of the number of separate display stands of key foods and their proximity to a cash register can be used by researchers to better characterize food stores and by policymakers to address improvements to the food environment. PMID:22701497

  19. Characterization of cultured epithelial cells using a novel technique not requiring enzymatic digestion for subculturing.

    PubMed

    Peramo, Antonio; Feinberg, Stephen E; Marcelo, Cynthia L

    2013-09-01

    Our laboratory had developed a methodology to expand epithelial cells in culture by growing keratinocyte monolayers, under large volumes of medium that produces large numbers of keratinocytes that leave the monolayer and move into suspension. The cells have been defined as epithelial Pop Up Keratinocytes or ePUKs cells and appear to be highly suitable for clinical applications. In this publication we extend the characterization of the cells with a detailed analysis of the capabilities of the monolayer of a single culture flask to produce, over time, ePUK cells. The cells were characterized using standard epithelial markers for proliferation and differentiation. Analysis of morphology of the monolayer formed and total number of cells produced is presented for a variety of human epithelial cell strains. These keratinocytes provide an additional controlled human cell system for investigation of the mechanisms regulating epithelia cell growth and differentiation and since they are produced in large numbers, they are highly suitable for use in epithelial cell banking. PMID:23149549

  20. Measuring the Food Environment: A Systematic Technique for Characterizing Food Stores Using Display Counts

    PubMed Central

    Miller, Cassandra; Bodor, J. Nicholas; Rose, Donald

    2012-01-01

    Marketing research has documented the influence of in-store characteristics—such as the number and placement of display stands—on consumer purchases of a product. However, little information exists on this topic for key foods of interest to those studying the influence of environmental changes on dietary behavior. This study demonstrates a method for characterizing the food environment by measuring the number of separate displays of fruits, vegetables, and energy-dense snack foods (including chips, candies, and sodas) and their proximity to cash registers in different store types. Observations in New Orleans stores (N = 172) in 2007 and 2008 revealed significantly more displays of energy-dense snacks than of fruits and vegetables within all store types, especially supermarkets. Moreover, supermarkets had an average of 20 displays of energy-dense snacks within 1 meter of their cash registers, yet none of them had even a single display of fruits or vegetables near their cash registers. Measures of the number of separate display stands of key foods and their proximity to a cash register can be used by researchers to better characterize food stores and by policymakers to address improvements to the food environment. PMID:22701497

  1. Estimation of aerosol type from airborne hyperspectral data: a new technique designed for industrial plume characterization

    NASA Astrophysics Data System (ADS)

    Deschamps, A.; Marion, R.; Foucher, P.-Y.; Briottet, X.

    2012-11-01

    The determination of the aerosol type in a plume from remotely sensed data without any a priori knowledge is a challenging task. If several methods have already been developed to characterize the aerosols from multi or hyperspectral data, they are not suited for industrial particles, which have specific physical and optical properties, changing quickly and in a complex way with the distance from the source emission. From radiative transfer equations, we have developed an algorithm, based on a Look-Up Table approach, enabling the determination of the type of this kind of particles from hyperspectral data. It consists in the selection of pixels pairs, located at the transitions between two kinds of grounds (or between an illuminated and a shadow area), then in the comparison between normalized estimated Aerosol Optical Thicknesses (AOTs) and pre-calculated AOTs. The application of this algorithm to simulated data leads to encouraging results: the selection of only six pixels pairs allows the algorithm to differentiate aerosols emitted by a metallurgical plant from biomass burning particles, urban aerosols and particles from an oil depot explosion, regardless the size and the aerosol concentration. The algorithm performances are better for a relatively high AOT but the single scattering approximation does not enable the characterization of thick plumes (AOT above 2.0). However, the choice of transitions (type of grounds) does not seem to significantly affect the results.

  2. An accurate technique for pre-yield characterization of MR fluids

    NASA Astrophysics Data System (ADS)

    Eshaghi, Mehdi; Rakheja, Subhash; Sedaghati, Ramin

    2015-06-01

    This study is concerned with the characterization of two types of magnetorheological (MR) fluids (MR 122EG and MR 132DG) in the pre-yield region. A phenomenological model is proposed for characterizing the complex shear modulus of the MR fluids as a function of both the magnetic flux density and the excitation frequency using the experimental data acquired for both the fluids. The experiments were conducted with a sandwich beam structure with an aluminum face layer and MR fluid as the core layer. A nearly uniform magnetic field was applied across the sandwich beam using two ceramic permanent magnet bars. The frequency response characteristics of the sandwich cantilevered beam were subsequently measured under harmonic excitations swept in the 0 to 500 Hz frequency range considering different densities of the applied magnetic flux, ranging from 0 to 90 mT. Dynamic responses of the structure were also obtained through analysis of a finite element (FE) model developed using the classical plate theory. The frequency and field-dependent complex shear moduli of the two MR fluids were identified from both the experimental data and the FE model results. The validity of the proposed methodology is demonstrated by comparing the FE model results with the experimental data for a copper sandwich structure comprising the two MR fluids.

  3. Nanoscale Characterization of Organometal Trihalide Perovskite using Photothermal Induced Resonance (PTIR) Technique

    NASA Astrophysics Data System (ADS)

    Chae, Jungseok; Centrone, Andrea; Yuan, Yongbo; Shao, Yuchuan; Wang, Qi; Xiao, Zhengguo; Dong, Qingfeng; Huang, Jinsong

    Further improvement of the performance of organometal trihalide perovskites (OTP) solar cells can be aided by nanoscale characterization. Photothermal induced resonance (PTIR), is a novel scanning probe method that enable measuring vibrational and electronic absorption maps and spectra with a resolution as high as 20 nm. In this presentation, the chemical composition and bandgap of OTP thin films was characterized with PTIR: 1) to identify the origin of the switchable photovoltaic effect and 2) to quantify the local chloride content in mixed-halide perovskites. PTIR vibrational maps recorded in correspondence of methyl ammonium ions (MA +) for a as prepared lateral structure solar cell were uniform but displayed stronger intensity in proximity of the cathode after electric poling. Those measurements provide the first direct proof of ion electron migration in OTP devices. Because chloride incorporation modifies the bandgap in MAPbI3-xClx perovskites, PTIR electronic maps and spectra were used to extract the local chloride content as a function of annealing. Results show that the as-prepared sample consist of a mixture of Cl-rich and Cl-poor phases that evolves into a homogenous Cl-poorer phase upon annealing. This measurement suggests that Cl- is progressively expelled from the film.

  4. Nonlinear time series techniques to characterize wind and temperature intermittency above a crop canopy.

    NASA Astrophysics Data System (ADS)

    Moratiel, Ruben; Duran, Jose M.; Tarquis, Ana Maria

    2010-05-01

    One important problem for understanding the vegetation-atmosphere interactions in an agricultural field is the turbulent exchange of scalar and momentum in the atmospheric boundary layer - above and within the crop canopy. Air temperature time series within and above canopies reveal ramp patterns associated with coherent eddies that are responsible for most of the vertical transport of sensible heat. Van Atta (1977) used a simple step-change ramp model to analyze the coherent part of air temperature structure functions. However, some works reveal that even without linearization his model cannot account for the observed decrease of the cubic structure function for small time lag (Wenjun Chen et al., 2004). Using considerations of scale effect and spatial variability of temperature and wind , the theory of multifractal processes, conservative or not, is introduced as a strategy for characterizing structure functions of temperature and vertical wind velocity at different scales of observation. We will show that kurtosis and phase coherence index characterize the intermittent nature of both series measured by a micrometeorological tower at different scenarios above the crop canopy. References Van Atta, C.W. (1977). Effect of coherent structures on structure functions of temperature in the atmospheric boundary later. Arch. Of Mech. 29, 161-171. Wenjun Chen, Novak, M.D., Black, T.A. and Xuhui Lee (2004). Coherent eddies and temperature structure functions for three contrasting surfaces. Part I: Ramp model with finite microfront time. Boundary-Layer Meteorology, 84(1), 99-124.

  5. A radiolabeled-ligand-binding technique for the characterization of opioid receptors in the intact mouse vas deferens.

    PubMed

    Cicero, T J; Bell, R D

    1985-10-01

    The mouse vas deferens has served as a useful bioassay for examining the properties of opiate receptor subtypes. However, recent data indicate that the response of the vas deferens to opiates may be mediated by one or more of the several opiate receptors found in this preparation. Although a number of techniques can be utilized to assess the relative contribution of these receptors to the response of the mouse vas deferens to opiates (e.g., selective tolerance and naloxone antagonism studies), a radiolabeled-binding technique would provide an independent means of more completely characterizing the opiate receptor profiles in this preparation. Up to the present, however, there has been only limited success in developing a binding assay utilizing crude membrane fractions of the mouse vas deferens. To circumvent these problems, we have developed a binding technique utilizing the intact vas deferens. In contrast to results obtained with membrane fractions, we found highly specific (90-95%) and saturable binding of D-[2-3H]alanine, 5-D-leucine enkephalin, a ligand selective for delta opiate receptors, to the intact vas. Scatchard analyses indicated a single class of binding sites with an apparent Kd of 1.5 nM and a Bmax of approximately 12 pmol/2 vas. The selectivity of binding was also examined. Naltrexone was 40 times less potent than unlabeled 2-D-alanine, 5-D-leucine enkephalin in displacing binding, whereas morphine and ethylketocyclazocine were 300 and 500 times less effective, respectively. This technique, coupled with the mouse vas deferens bioassay, should provide a more complete characterization of opioid receptor populations than has heretofore been possible. PMID:3002205

  6. Morphostructural characterization of the western edge of the Huila Plateau (SW Angola), based on remote sensing techniques

    NASA Astrophysics Data System (ADS)

    Lopes, Fernando Carlos; Pereira, Alcides José; Mantas, Vasco Manuel; Mpengo, Horácio Kativa

    2016-05-01

    Recognition of the main morphostructural features of the western edge of the Huila Plateau (SW Angola) can be done by using remote sensing techniques associated with field work. A digital elevation model (DEM) of the area was built for this purpose. This model is based on altimeter data acquired from the Aster sensor, on which image processing techniques such as enhancement techniques, contrast change and filtering were applied. Other techniques, such as RGB colour composition, were also tested. The processed satellite images were interpreted by visual process and the results were then compared with available geological maps (scale 1: 1 000 000). To facilitate both analysis and interpretation, the edge of the plateau was divided into three sectors: northern (or Chongoroi Edge), central (or Humpata Edge) and southern (or Oncocua Edge). For each sector, the main morphological aspects and main lineament systems were identified and characterized. In the specific case of the central sector, these parameters were also confirmed by field work. This study shows that the morphology of the western edge of the plateau is dominated by N50°W-N60°W, N60°E and N-S trending main tectonic systems. These results have important implications in terms of geological mapping and regional tectonics as well as in land-use planning and other areas, such as hydrogeology or geotechnics.

  7. Morphostructural characterization of the western edge of the Huila Plateau (SW Angola), based on remote sensing techniques

    NASA Astrophysics Data System (ADS)

    Lopes, Fernando Carlos; Pereira, Alcides José; Mantas, Vasco Manuel; Mpengo, Horácio Kativa

    2016-05-01

    Recognition of the main morphostructural features of the western edge of the Huila Plateau (SW Angola) can be done by using remote sensing techniques associated with field work. A digital elevation model (DEM) of the area was built for this purpose. This model is based on altimeter data acquired from the Aster sensor, on which image processing techniques such as enhancement techniques, contrast change and filtering were applied. Other techniques, such as RGB colour composition, were also tested. The processed satellite images were interpreted by visual process and the results were then compared with available geological maps (scale 1: 1 000 000). To facilitate both analysis and interpretation, the edge of the plateau was divided into three sectors: northern (or Chongoroi Edge), central (or Humpata Edge) and southern (or Oncocua Edge). For each sector, the main morphological aspects and main lineament systems were identified and characterized. In the specific case of the central sector, these parameters were also confirmed by field work. This study shows that the morphology of the western edge of the plateau is dominated by N50°W-N60°W, N60°E and N-S trending main tectonic systems. These results have important implications in terms of geological mapping and regional tectonics as well as in land-use planning and other areas, such as hydrogeology or geotechnics.

  8. The preparation and characterization of a lithium borate glass prepared by the gel technique

    NASA Technical Reports Server (NTRS)

    Weinberg, M. C.; Neilson, G. F.; Smith, G. L.; Dunn, B.; Moore, G. S.; Mackenzie, J. D.

    1985-01-01

    The preparation of an amorphous lithium borate gel by the metal organic procedure is described. In addition, a preliminary evaluation of the behavior of the gel upon heating is given. In particular the crystallization tendency of the gel is studied with the aid of DTA and X-ray diffraction, and the structural changes in the gel are monitored with the aid of IR spectroscopy. The glass produced from the lithium borate gel is compared to both the gel precursor material and a glass of similar composition prepared by conventional techniques. Specifically, the relevant water contents, crystallization behavior, and structural features are contrasted.

  9. Growth and characterization of CdMnTe by the vertical Bridgman technique

    NASA Astrophysics Data System (ADS)

    Roy, U. N.; Camarda, G. S.; Cui, Y.; Gu, G.; Gul, R.; Hossain, A.; Yang, G.; Egarievwe, S. U.; James, R. B.

    2016-03-01

    We grew Cd1-xMnx Te crystals with a nominal Mn concentration of 5% by the vertical Bridgman growth technique. The structural quality of the crystal was evaluated by white beam X-ray topography in the National Synchrotron Light Source (NSLS) facility at Brookhaven National Laboratory (BNL). We observed that the crystal was free from a sub-grain boundary network, as revealed by X-ray topography and verified by our etching study. The concentration of the secondary phases, averaged over the entire ingot, was 2-3 times lower than in conventional Bridgman grown cadmium zinc telluride (CZT) crystals.

  10. Growth and characterization of AuN films through the pulsed arc technique

    SciTech Connect

    Devia, A. Castillo, H.A.; Benavides, V.J.; Arango, Y.C.; Quintero, J.H.

    2008-02-15

    AuN films were produced through the PAPVD (Plasma Assisted Physics Vapor Deposition) method, using the pulsed arc technique in a mono-vaporizer noncommercial system, which consists of a chamber with two faced electrodes, and a power controlled system. In order to obtain the films, an Au Target with 99% purity and stainless steel 304 were used as target and substrate respectively. Nitrogen was injected in gaseous phase at 2.3 mbar pressure, and a discharge of 160 V was performed, supplied by the power controlled source. Au4f and N1s narrow spectra were analyzed using XPS (X-ray Photoelectron Spectroscopy)

  11. Processing and characterization of natural fiber reinforced thermoplastic composites using micro-braiding technique

    NASA Astrophysics Data System (ADS)

    Kobayashi, Satoshi; Ogihara, Shinji

    In the present study, we investigate fatigue properties of green composites. A hemp fiber yarn reinforced poly(lactic acid) composite was selected as a green composite. Unidirectional (UD) and textile (Textile) composites were fabricated using micro-braiding technique. Fatigue tests results indicated that fatigue damages in UD composites was splitting which occurred just before the final fracture, while matrix crack and debonding between matrix and fiber yarn occurred and accumulated stably in Textile composites. These results were consistent with modulus reduction and acoustic emission measurement during fatigue tests.

  12. On the relationship between parallel computation and graph embedding

    SciTech Connect

    Gupta, A.K.

    1989-01-01

    The problem of efficiently simulating an algorithm designed for an n-processor parallel machine G on an m-processor parallel machine H with n > m arises when parallel algorithms designed for an ideal size machine are simulated on existing machines which are of a fixed size. The author studies this problem when every processor of H takes over the function of a number of processors in G, and he phrases the simulation problem as a graph embedding problem. New embeddings presented address relevant issues arising from the parallel computation environment. The main focus centers around embedding complete binary trees into smaller-sized binary trees, butterflies, and hypercubes. He also considers simultaneous embeddings of r source machines into a single hypercube. Constant factors play a crucial role in his embeddings since they are not only important in practice but also lead to interesting theoretical problems. All of his embeddings minimize dilation and load, which are the conventional cost measures in graph embeddings and determine the maximum amount of time required to simulate one step of G on H. His embeddings also optimize a new cost measure called ({alpha},{beta})-utilization which characterizes how evenly the processors of H are used by the processors of G. Ideally, the utilization should be balanced (i.e., every processor of H simulates at most (n/m) processors of G) and the ({alpha},{beta})-utilization measures how far off from a balanced utilization the embedding is. He presents embeddings for the situation when some processors of G have different capabilities (e.g. memory or I/O) than others and the processors with different capabilities are to be distributed uniformly among the processors of H. Placing such conditions on an embedding results in an increase in some of the cost measures.

  13. Characterization of Deficiencies in the Frequency Domain Forced Response Analysis Technique for Turbine Bladed Disks

    NASA Technical Reports Server (NTRS)

    Brown, Andrew M.; Schmauch, Preston

    2012-01-01

    Turbine blades in rocket and jet engine turbomachinery experience enormous harmonic loading conditions. These loads result from the integer number of upstream and downstream stator vanes as well as the other turbine stages. The standard technique for forced response analysis to assess structural integrity is to decompose a CFD generated flow field into its harmonic components, and to then perform a frequency response analysis at the problematic natural frequencies. Recent CFD analysis and water-flow testing at NASA/MSFC, though, indicates that this technique may miss substantial harmonic and non-harmonic excitation sources that become present in complex flows. These complications suggest the question of whether frequency domain analysis is capable of capturing the excitation content sufficiently. Two studies comparing frequency response analysis with transient response analysis, therefore, have been performed. The first is of a bladed disk with each blade modeled by simple beam elements. It was hypothesized that the randomness and other variation from the standard harmonic excitation would reduce the blade structural response, but the results showed little reduction. The second study was of a realistic model of a bladed-disk excited by the same CFD used in the J2X engine program. The results showed that the transient analysis results were up to 10% higher for "clean" nodal diameter excitations and six times larger for "messy" excitations, where substantial Fourier content around the main harmonic exists.

  14. Complementary techniques for the characterization of thin film Ti/Nb multilayers.

    PubMed

    Genç, Arda; Banerjee, Rajarshi; Thompson, Gregory B; Maher, Dennis M; Johnson, Andrew W; Fraser, Hamish L

    2009-09-01

    An aberration corrector on the probe-forming lens of a scanning TEM (STEM) equipped with an electron energy-loss spectrometer (EELS) and X-ray energy-dispersive spectrometer (XEDS) has been employed to investigate the compositional variations as a function of length scale in nanoscale Ti/Nb metallic multilayers. The composition profiles of EELS and XEDS were compared with the profiles obtained from the complementary technique of 3D atom probe tomography. At large layer widths (h > or = 7 nm, where h is the layer width) of Ti and Nb, XEDS composition profiles of Ti/Nb metallic multilayers are in good agreement with the EELS results. However, at reduced layer widths (h approximately 2 nm), profiles of EELS and atom probe exhibited similar compositional variations, whereas XEDS results have shown a marked difference. This difference in the composition profiling of the layers has been addressed with reference to the effects of beam broadening and the origin of the signals collected in these techniques. The advantage of using EELS over XEDS for these nanoscaled multilayered materials is demonstrated. PMID:19553019

  15. Material characterization with top-hat cw laser induced photothermal techniques: A short review

    NASA Astrophysics Data System (ADS)

    Astrath, N. G. C.; Shen, J.; Baesso, M. L.; Astrath, F. B. G.; Malacarne, L. C.; Pedreira, P. R. B.; Bento, A. C.; Zhou, J.

    2010-03-01

    In this work, we present a short review of the recent development of the theoretical models for top-hat cw laser induced spectroscopies of thermal lens and thermal mirror. With the same probe and top-hat excitation lasers, an apparatus is set up to concurrently measure both thermal lens and thermal mirror effects of transparent samples. With the theoretical models and the experimental apparatus, not only optical and thermal properties are measured, but also the fluorescence quantum coefficient and the temperature coefficient of the optical path length of a fluorescent sample are simultaneously determined with no need of any reference sample. Mechanical properties also could be measured. Opaque samples are also studied using top-hat cw laser thermal mirror and top-hat photothermal deflection techniques to determine thermal properties (e.g., thermal conductivity and unit volume specific heat). This work shows that the combined top-hat cw laser photothermal techniques are useful for nondestructive evaluation of both transparent and opaque samples with a less expensive non-TEM00 Gaussian laser.

  16. New drop deposition technique for wettability characterization of under-liquid superoleophobic surfaces

    NASA Astrophysics Data System (ADS)

    Mitra, Sushanta; Waghmare, Prashant; Das, Siddhartha

    2013-11-01

    From understanding the remarkable self-cleaning behavior of fish scales to the preparation of surfaces that will counter the destructive effects of oil-spills, there has been a remarkable interest in understanding the wettability of a solid in an ``under-liquid'' configuration. Like surfaces in air, here too, the main focus remain in designing surfaces (such as fish scales) that exhibit repelling behavior to a multiple other liquids in this ``under-liquid'' state. Problem occurs, just as with surfaces in air, when this ``under-liquid'' surface is too repelling to a given liquid. In that case, the standard drop deposition technique is unable to deposit a drop that is not ``interfered'' by the needle holding the drop. Here we shall discuss a unique technique that ensures that we achieve a ``needle-free'' deposited drop on the under-liquid surface. A drop is produced at the end of the needle, with the needle placed inside the liquid bath. Then the needle holding the drop is moved away from the concerned surface, and the moment this drop-needle assembly hits the liquid-air or liquid-another-liquid (a layer of this another liquid is intentionally created at the location where the liquid bath is exhausted), the surface tension effects will ensure that the drop is detached from the needle.

  17. Characterization of nanosecond pulse electrical field shock waves using imaging techniques

    NASA Astrophysics Data System (ADS)

    Mimun, L. Chris; Ibey, Bennett L.; Roth, Caleb C.; Barnes, Ronald A.; Sardar, Dhiraj K.; Beier, Hope T.

    2015-03-01

    Nanosecond pulsed electric fields (nsPEF) cause the formation of small pores, termed nanopores, in the membrane of cells. Current nanoporation models treat nsPEF exposure as a purely electromagnetic phenomenon, but recent publications showing pressure transients, ROS production, temperature gradients, and pH waves suggest the stimulus may be physically and chemically multifactorial causing elicitation of diverse biological conditions and stressors. Our research group's goal is to quantify the breadth and participation of these stressors generated during nsPEF exposure and determine their relative importance to the observed cellular response. In this paper, we used advanced imaging techniques to identify a possible source of nsPEF-induced acoustic shock waves. nsPEFs were delivered in an aqueous media via a pair of 125 μm tungsten electrodes separated by 100 μm, mirroring our previously published cellular exposure experiments. To visualize any pressure transients emanating from the electrodes or surrounding medium, we used the Schlieren imaging technique. Resulting images and measurements confirmed that mechanical pressure waves and electrode-based stresses are formed during nsPEF, resulting in a clearer understanding of the whole exposure dosimetry. This information will be used to better quantify the impact of nsPEF-induced acoustic shock waves on cells, and has provided further evidence of non-electrical-field induced exposures for elicitation of bioieffects.

  18. Characterization of Some Iraqi Archaeological Samples Using IBA, Analytical X-ray and Other Complementary Techniques

    NASA Astrophysics Data System (ADS)

    Shihab Al-Sarraj, Ziyad; Roumie, Mohamad; Damboos, Hassan I.

    2012-07-01

    The present work aimed at investigating the compositions and microstructures of some archaeological samples which dated back to various periods of the ancient Iraqi civilizations using PIXE, XRF, XRD, and SEM techniques. The models selected for the study (ceramics, glaze, etc.) were diverse in size and nature, therefore a limited number of samples were then butted from them by a small diamond wheel. Conventional powder metallurgy method was then used to prepare the samples. Dried samples were then coated with a thin layer of carbon, and analyzed using the ion beam accelerator of the LAEC. Three other groups of samples were also prepared for the purpose of analysis by X-ray fluorescence (XRF), X-ray diffraction (XRD), and scanning electron microscope (SEM). Analysis results of the chemical composition showed good agreement between the various techniques as well as for phases, while the fine structure analysis obtained by optical and scanning microscopy exhibited features of a structure where it got an intensified densification in the final stage of sintering and accompanied by quasi-homogeneous distribution of the closed pores. This will lead to the conclusion that the temperature used for sintering by ancient Iraqi was sufficient and it may fall in the range between 950-1200°C, also the mixes and the forming methods used by them, were both suitable to obtain good sintered bodies with even distribution of pores. A ring-shaped trace noticed in SEM micrographs need more work and study to explain what it is?

  19. Fluid Characterization Using the Quasi-Scholte Mode

    NASA Astrophysics Data System (ADS)

    Cegla, F. B.; Cawley, P.; Lowe, M. J. S.

    2005-04-01

    Ultrasonic fluid characterization is an important technique in process and quality control. Current techniques consist of ultrasonic test cells that can be disadvantageous in certain situations. This paper investigates the possible use of an alternative guided wave dipstick technique. The quasi-Scholte mode properties are extracted and then used to predict the longitudinal bulk velocity and attenuation of the embedding fluid. Good results for viscous glycerol and a silicon dioxide suspension are presented.

  20. Multi-MeV laser-produced particle sources: Characterization by activation techniques

    NASA Astrophysics Data System (ADS)

    Gerbaux, M.; Aléonard, M. M.; Claverie, G.; Gobet, F.; Hannachi, F.; Malka, G.; Scheurer, J. N.; Tarisien, M.; Méot, V.; Morel, P.; Faure, J.; Glinec, Y.; Guemnie-Tafo, A.; Malka, V.; Manclossi, M.; Santos, J.

    2006-06-01

    We present here results obtained in an experiment carried out using the CPA beam of the “Salle Jaune” laser system at Laboratoire d'Optique Appliquée (LOA). The generation of high energy electrons and protons escaping from the plasma has been investigated in the interaction of a 2 J, 30 fs laser with CH or metallic foils. The energy and angular distributions of the supra-thermal electrons produced with different targets are characterized by using both an electron spectrometer and bremsstrahlung induced (γ ,n) reactions. We measured simultaneously the number of energetic protons produced using (p,n) reactions. A correlation between the electrons and the protons production is observed together with a dependence of the number of supra-thermal electrons on the atomic number of the target element.