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1

Feasibility of anomaly detection and characterization using trans-admittance mammography with 60 × 60 electrode array  

NASA Astrophysics Data System (ADS)

Electrical impedance imaging has the potential to detect an early stage of breast cancer due to higher admittivity values compared with those of normal breast tissues. The tumor size and extent of axillary lymph node involvement are important parameters to evaluate the breast cancer survival rate. Additionally, the anomaly characterization is required to distinguish a malignant tumor from a benign tumor. In order to overcome the limitation of breast cancer detection using impedance measurement probes, we developed the high density trans-admittance mammography (TAM) system with 60 × 60 electrode array and produced trans-admittance maps obtained at several frequency pairs. We applied the anomaly detection algorithm to the high density TAM system for estimating the volume and position of breast tumor. We tested four different sizes of anomaly with three different conductivity contrasts at four different depths. From multifrequency trans-admittance maps, we can readily observe the transversal position and estimate its volume and depth. Specially, the depth estimated values were obtained accurately, which were independent to the size and conductivity contrast when applying the new formula using Laplacian of trans-admittance map. The volume estimation was dependent on the conductivity contrast between anomaly and background in the breast phantom. We characterized two testing anomalies using frequency difference trans-admittance data to eliminate the dependency of anomaly position and size. We confirmed the anomaly detection and characterization algorithm with the high density TAM system on bovine breast tissue. Both results showed the feasibility of detecting the size and position of anomaly and tissue characterization for screening the breast cancer.

Zhao, Mingkang; Wi, Hun; Lee, Eun Jung; Woo, Eung Je; In Oh, Tong

2014-10-01

2

Electrical admittance of piezoelectric parallelepipeds: application to tensorial characterization of piezoceramics  

SciTech Connect

This work deals with the characterization of functional properties, including determination of mechanical and electrical losses, of piezoelectric materials using only one sample and one measurement. First, the natural resonant frequencies of a piezoelectric parallelepiped are calculated and the electrical admittance is determined from calculations of the charge quantity on both electrodes of the parallelepiped. A first validation of the model is performed using a comparison with Mason's model. Results are reported for a PMN-34.5PT ceramic cube and a good agreement is found between experimental admittance measurements and their modeling. The functional properties of the PMN-34.5PT are then extracted.

Diallo, O.; Bavencoffe, M.; Feuillard, G. [Laboratoire GREMAN UMR CNRS 7347. École Nationale d’Ingénieurs du Val de Loire Université François Rabelais de Tours 3 Rue de la Chocolaterie BP 3410 41034 BLOIS CEDEX France (France)] [Laboratoire GREMAN UMR CNRS 7347. École Nationale d’Ingénieurs du Val de Loire Université François Rabelais de Tours 3 Rue de la Chocolaterie BP 3410 41034 BLOIS CEDEX France (France); Clezio, E. Le; Delaunay, T. [Institut d’Electronique du Sud UMR CNRS 5214 IES - MIRA case 082Université Montpellier 2 Place Eugène Bataillon 34095 MONTPELLIER CEDEX 5 France (France)] [Institut d’Electronique du Sud UMR CNRS 5214 IES - MIRA case 082Université Montpellier 2 Place Eugène Bataillon 34095 MONTPELLIER CEDEX 5 France (France)

2014-01-15

3

Dynamic characterization of partially saturated engineered porous media and gas diffusion layers using hydraulic admittance  

NASA Astrophysics Data System (ADS)

Simple laboratory methods for determining liquid water distribution in polymer electrolyte membrane fuel cell gas diffusion layers (GDLs) are needed to engineer better GDL materials. Capillary pressure vs. liquid saturation measurements are attractive, but lack the ability to probe the hydraulic interconnectivity and distribution within the pore structure. Hydraulic admittance measurements of simple capillary bundles have recently been shown to nicely measure characteristics of the free-interfaces and hydraulic path. Here we examine the use of hydraulic admittance with a succession of increasingly complex porous media, starting with a laser-drilled sample with 154 asymmetric pores and progress to the behavior of Toray TGP-H090 carbon papers. The asymmetric laser-drilled sample clearly shows hydraulic admittance measurements are sensitive to sample orientation, especially when examined as a function of saturation state. Finite element modeling of the hydraulic admittance is consistent with experimental measurements. The hydraulic admittance spectra from GDL samples are complex, so we examine trends in the spectra as a function of wet proofing (0% and 40% Teflon loadings) as well as saturation state of the GDL. The presence of clear peaks in the admittance spectra for both GDL samples suggests a few pore types are largely responsible for transporting liquid water.

Cheung, Perry; Fairweather, Joseph D.; Schwartz, Daniel T.

2012-09-01

4

LabVIEW for Admittance Spectroscopy Automation  

NASA Astrophysics Data System (ADS)

Admittance spectroscopy (AS) and capacitance-voltage (C-V) measurements have long been characterization tools used to study properties of deep level defects in semiconductor devices. Measurements of conductance and capacitance of semiconductor devices are made typically as a function of temperature, voltage, and voltage signal frequency. To fully automate the system for data acquisition, LabVIEW, a virtual graphical programming language developed by National Instruments, is used to interface a computer with the measurement instruments. In this paper, the LabVIEW modules used and highlights of data from wide bandgap semiconductor devices will be presented.

Brodrick, Robert J.

2005-04-01

5

External impedance and admittance of buried horizontal wires for transient studies using transmission line analysis  

Microsoft Academic Search

The paper investigates the applicability of some closed form expressions for the ground impedance and ground admittance of buried horizontal wires (bare and insulated) for lightning or switching transient analyses based on transmission line (TL) theory. In view of the frequency contents that typically characterize such transients, the behavior of the ground impedance and admittance is studied for a wide

Nelson Theethayi; Rajeev Thottappillil; Mario Paolone; Carlo Alberto Nucci; Farhad Rachidi

2007-01-01

6

Effective Admittivity of Biological Tissues as a Coefficient of Elliptic PDE  

PubMed Central

The electrical properties of biological tissues can be described by a complex tensor comprising a simple expression of the effective admittivity. The effective admittivities of biological tissues depend on scale, applied frequency, proportions of extra- and intracellular fluids, and membrane structures. The effective admittivity spectra of biological tissue can be used as a means of characterizing tissue structural information relating to the biological cell suspensions, and therefore measuring the frequency-dependent effective conductivity is important for understanding tissue's physiological conditions and structure. Although the concept of effective admittivity has been used widely, it seems that its precise definition has been overlooked. We consider how we can determine the effective admittivity for a cube-shaped object with several different biologically relevant compositions. These precise definitions of effective admittivity may suggest the ways of measuring it from boundary current and voltage data. As in the homogenization theory, the effective admittivity can be computed from pointwise admittivity by solving Maxwell equations. We compute the effective admittivity of simple models as a function of frequency to obtain Maxwell-Wagner interface effects and Debye relaxation starting from mathematical formulations. Finally, layer potentials are used to obtain the Maxwell-Wagner-Fricke expression for a dilute suspension of ellipses and membrane-covered spheres. PMID:23710251

Kwon, Hyeuknam; Sadleir, Rosalind

2013-01-01

7

Effective admittivity of biological tissues as a coefficient of elliptic PDE.  

PubMed

The electrical properties of biological tissues can be described by a complex tensor comprising a simple expression of the effective admittivity. The effective admittivities of biological tissues depend on scale, applied frequency, proportions of extra- and intracellular fluids, and membrane structures. The effective admittivity spectra of biological tissue can be used as a means of characterizing tissue structural information relating to the biological cell suspensions, and therefore measuring the frequency-dependent effective conductivity is important for understanding tissue's physiological conditions and structure. Although the concept of effective admittivity has been used widely, it seems that its precise definition has been overlooked. We consider how we can determine the effective admittivity for a cube-shaped object with several different biologically relevant compositions. These precise definitions of effective admittivity may suggest the ways of measuring it from boundary current and voltage data. As in the homogenization theory, the effective admittivity can be computed from pointwise admittivity by solving Maxwell equations. We compute the effective admittivity of simple models as a function of frequency to obtain Maxwell-Wagner interface effects and Debye relaxation starting from mathematical formulations. Finally, layer potentials are used to obtain the Maxwell-Wagner-Fricke expression for a dilute suspension of ellipses and membrane-covered spheres. PMID:23710251

Seo, Jin Keun; Bera, Tushar Kanti; Kwon, Hyeuknam; Sadleir, Rosalind

2013-01-01

8

Grasp admittance center. A concept  

NASA Astrophysics Data System (ADS)

The ultimate goal of the research on articulated hands in general is to use them to do tasks in a way similar to that of humans. A systematic analysis reveals that the day-to-day tasks of humans include some common task primitives such as twist, turn, insert, pullout, push, pull, lift, and place. During each of these operations, the grasp dynamic behavior plays an important role and more so in tasks involving manipulation of delicate objects. Introduced in this paper is the concept of the grasp admittance center, a notion that aims to make an articulated grasp exhibit a directionally decoupled dynamic behavior. An admittance center is conceptualized as the superposition of compliance, accommodation, and mobility centers in a desired coordinate frame. A grasp with an admittance center will have three useful features: stability, decoupled force motion relation, and decoupled time-response. These features are also useful to other closed kinematic chain robotic devices such as the cooperating multiarms and multilegged mobile robots engaged in non-quasistatic (dynamic) manipulation tasks. As a preparation to demonstrate the concept experimentally, a method of synthesizing articulated grasps so as to achieve an admittance center has been developed as well as a method of choosing appropriate location and related parameters for the center. The sensitivity of the center to its parameter imprecision has also been analyzed.

Shimoga, K. B.; Goldenberg, A. A.

1991-05-01

9

Multi-port admittance model for quantifying the scattering response of loaded plasmonic nanorod antennas.  

PubMed

In this paper we demonstrate the feasibility of using multiport network theory to describe the admittance properties of a longitudinally loaded plasmonic nanorod antenna. Our analysis reveals that if the appropriate terminal ports are defined across the nanorod geometry then the corresponding voltage and current quantities can be probed and thus it becomes feasible to extract the admittance matrix of the structure. Furthermore, it is demonstrated that by utilizing cylindrical dielectric waveguide theory, closed form expressions can be derived that uniquely characterize the loading material in terms of its admittance. The combination of the admittance matrix information along with the load admittance expressions provides an effective methodology for computing the nanorod's input admittance/impedance for arbitrary loading scenarios. This is important because the admittance resonances are associated with the structure's scattering peaks which are excited by a plane wave polarized parallel to its long dimension. Subsequently, the proposed approach provides a fast and computationally efficient circuit-based methodology to predict and custom engineer the scattering properties of a loaded plasmonic nanorod without having to rely on repetitive lengthy full wave simulations. PMID:25836483

Panaretos, Anastasios H; Werner, Douglas H

2015-02-23

10

An Adaptive Admittance or Force Control for Robotic Manipulators  

Microsoft Academic Search

Summary In this paper an adaptive compliant motion control is presented for either constant admittance or constant force mode of operation. From a desired trajectory of the admittance and virtual position in the task space, a virtual trajectory is generated to follow the desired admittance. We are talking about admittance because at the interaction port of the end effector the

S. Stramigioli; A. van der Ham; G. Honderd

11

Modeling and Characterization of On-Chip Transformers  

E-print Network

Modeling and Characterization of On-Chip Transformers Sunderarajan S. Mohan, C. Patrick Yue, Maria #12;OUTLINE Motivation Background On-chip transformer realizations Models Experimental verification Summary #12;MOTIVATION FOR TRANSFORMER MODELING Essential for Radio Frequency Integrated Circuits (RFICs

Lee, Thomas H.

12

The Admittance of High Frequency Gas Discharges  

Microsoft Academic Search

The admittance of a high frequency gaseous discharge between parallel plates has been measured as a function of pressure and discharge current. The susceptance is observed not to be proportional to the conductance. In fact the discharge susceptance changes sign from negative at low pressures and low electron densities to positive at high electron densities and high pressures. The discharge

Edgar Everhart; Sanborn C. Brown

1949-01-01

13

A virtual analyzer for piezoceramics' admittance measurement  

Microsoft Academic Search

Impedance or admittance characteristic must be measured by a spectrum analyzer for piezoceramics in order to gain the electromechanical match at resonance frequency before piezoceramic actuating applications. A virtual analyzer is implemented with an acquisition card inserted into a personal computer and with the LabVIEW tools developed in Windows. While the voltage inputted onto the piezoceramics and the current sampling

Fuhliang Wenl; Ichien Hsu; J. Y. Chen; Chang Hua Lin

2005-01-01

14

Charge injecting layers for admittance spectroscopy  

NASA Astrophysics Data System (ADS)

Admittance spectroscopy is a simple yet powerful tool to determine the carrier mobility of organic compounds. One requirement is to have an Ohmic contact for charge injection. By employing a thin interfacial layer of tungsten oxide or molybdenum oxide we have found a possibility to efficiently inject holes into organic materials with a deep highest occupied molecular orbital level down to 6.3 eV. These results considerably enhance the application range of the admittance spectroscopy method. The measured mobility data are in excellent agreement with data obtained by the time-of-flight technique. To efficiently inject electrons into materials with an ionization potential of up to 2.7 eV we thermally evaporated an intermediate layer of cesium carbonate and discuss the extracted electron mobilities.

Hoping, M.; Schildknecht, C.; Gargouri, H.; Riedl, T.; Tilgner, M.; Johannes, H.-H.; Kowalsky, W.

2008-08-01

15

CHARACTERIZATION AND ANALYSIS OF EDGES USING THE CONTINUOUS SHEARLET TRANSFORM  

E-print Network

by Cand`es and Donoho on the curvelet transform [2] and later using our approach based on the shearlet of functions and distributions. For example, the continuous curvelet and shearlet transforms are usefulCHARACTERIZATION AND ANALYSIS OF EDGES USING THE CONTINUOUS SHEARLET TRANSFORM KANGHUI GUO

Labate, Demetrio

16

Haptic Display of Constrained Dynamic Systems via Admittance Displays  

Microsoft Academic Search

In the Cobotic Hand Controller, we have introduced an admittance display that can render very high impedances (up to its own structural stiffness). This is due to its use of infinitely variable transmissions. While admittance displays typically excel at rendering high impedances, the incorporation of infinitely variable transmissions in the Cobotic Hand Controller allows the stable display of a wide

Eric L. Faulring; Kevin M. Lynch; J. Edward Colgate; Michael A. Peshkin

2007-01-01

17

Admittance of a long diffusive SNS junction  

NASA Astrophysics Data System (ADS)

The dynamical properties of hybrid normal metal/superconductor structures have recently come into research focus both experimentally and theoretically. Recent experimental studies of the coherent admittance Y (? ) of SNS rings as a function of the phase difference ?0 are still not fully understood. Here we concentrate on the linear response regime, calculating Y (? ) by solving the Usadel equations, linearized in an electric field. Partially reproducing previously known results, we find qualitatively different behavior in the collisionless regime of ?in-1?? ?ETh and high temperature T ?ETh and low temperature T ?ETh near the minigap closing ?0˜? . We find that the dissipative part ReY (? ) peaks when the minigap closes (at a phase difference of ? ) even at high temperatures, when the equilibrium supercurrent is fully suppressed.

Tikhonov, K. S.; Feigel'man, M. V.

2015-02-01

18

Surface acoustic admittance and absorption of highly porous, layered, fibrous materials  

NASA Technical Reports Server (NTRS)

Some acoustic properties of Kevlar-29 - a fine fibered, layered material is investigated. Kevlar is characterized by very high strength, uniform filaments arranged in a parallel batt where most filaments are random in the x-y plane but ordered as planes in the z direction. For experimental purposes, volume porosity, static flow resistance and mean filament diameter are used to identify the material. To determine the acoustic surface admittance of Kevlar, batts of the material are cut into small pads and placed into a standing wave tube terminated by a rigid brass plug. The attenuation and relative phase shift are recorded at each frequency in the range of 50 to 6000 Hz. Normalized conductance and susceptance are combined to form the acoustic absorption coefficient. The data are compared with theory by plotting the normalized admittance and normal incident absorption coefficient versus cyclic frequency.

Tesar, J. S.; Lambert, R. F.

1984-01-01

19

Coulometric differential FFT admittance voltammetry determination of Amlodipine in pharmaceutical formulation by nano-composite electrode.  

PubMed

An electrochemical detection technique based on combination of was coulometric differential fast Fourier transformation admittance voltammetry (CDFFTAV) and nano-composite film modified glassy carbon electrode was successfully applied for sensitive determination of Amlodipine. The nano-composite film was made by a mixture of ionic liquid, 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4), multiwall carbon nanotube and Au nanoparticles as electrochemical mediators. Studies reveal that the irreversible oxidation of Amlodipine was highly facile on the electrode surface. The electrochemical response was established on calculation of the charge under the admittance peak, which was obtained by discrete integration of the admittance response in a selected potential range, obtained in a flow injection analysis. Once established the best operative optimum conditions, the resulting nano-composite film electrode showed a catalytic effect on the oxidation of the analyte. The response is linear in the Amlodipine concentration range of 1.0 × 10(-9) to 2.0 × 10(-7)M with a detection limit of 1.25 × 10(-10)M. Moreover, the proposed technique exhibited high sensitivity, fast response time (less than 6s) and long-term stability and reproducibility around 96%, and it was successfully used to the determination of Amlodipine content in the pharmaceutical formulation. PMID:25281143

Norouzi, Parviz; Gupta, Vinod Kumar; Larijani, Bagher; Rasoolipour, Solmaz; Faridbod, Farnoush; Ganjali, Mohammad R

2015-01-01

20

9 CFR 117.3 - Admittance of animals.  

Code of Federal Regulations, 2010 CFR

9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Admittance of animals. 117.3 Section 117.3 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...

2010-01-01

21

9 CFR 117.3 - Admittance of animals.  

Code of Federal Regulations, 2014 CFR

9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Admittance of animals. 117.3 Section 117.3 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...

2014-01-01

22

9 CFR 117.3 - Admittance of animals.  

Code of Federal Regulations, 2013 CFR

9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Admittance of animals. 117.3 Section 117.3 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...

2013-01-01

23

9 CFR 117.3 - Admittance of animals.  

Code of Federal Regulations, 2011 CFR

9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Admittance of animals. 117.3 Section 117.3 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...

2011-01-01

24

9 CFR 117.3 - Admittance of animals.  

Code of Federal Regulations, 2012 CFR

9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Admittance of animals. 117.3 Section 117.3 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...

2012-01-01

25

Acoustic transfer admittance of cylindrical cavities  

NASA Astrophysics Data System (ADS)

The reciprocity calibration method uses two microphones acoustically connected by a coupler, a cylindrical cavity closed at each end by the diaphragms of the transmitting and receiving microphones. The acoustic transfer admittance of the coupler, including the thermal conductivity effect of the fluid, must be modelled precisely to obtain the accurate sensitivity of the microphones from the electrical transfer impedance measurement. It appears that the analytical model quoted in the current standard [International Electrotechnical Commission IEC 61064-2, Measurement Microphones, Part 2: Primary Method for Pressure Calibration of Laboratory Standard Microphones by the Reciprocity Technique, 1992] is not the appropriate one and that it should be revised, as also suggested by a recent EUROMET project report [K. Rasmussen, Datafiles simulating a pressure reciprocity calibration of microphones, EUROMET Project 294 Report PL-13, 2001]. Thus, it is the aim of the paper to investigate analytically the acoustic field inside the coupler, revisiting the assumptions of the earlier work, leading to a coherent description and therefore providing clarity which should facilitate discussion of a possible revised standard.

Guianvarc'h, C.; Durocher, J.-N.; Bruneau, M.; Bruneau, A.-M.

2006-05-01

26

Admittance spectroscopy study of polymer diodes in small magnetic fields  

NASA Astrophysics Data System (ADS)

We performed a systematic study of bipolar and unipolar organic diodes based on the ?-conjugated polymer, 2-methoxy-5-(2'-ethylhexyloxy) (MEH-PPV), using electronic and magneto-transport measurements with magnetic field in the range 0-180 mT and admittance spectroscopy in the frequency range 1 Hz < f < 10 MHz. The admittance spectra of bipolar devices reveal two relaxation processes with distinct time scales that are influenced by the magnetic field. The slower process, which dominates the device capacitance at f < 10 Hz, is attributed to the trap-assisted monomolecular recombination. The faster process is attributed to the electron-hole bimolecular recombination kinetics. We found that the time scale of this process, ?2, decreases exponentially with the bias voltage. Application of magnetic field, B = 30 mT decreases ?2 by ˜30%. We also found that the magneto-conductance, ?G(?,B)/G(?,0), has a characteristic cutoff frequency that shifts to higher frequencies with increasing bias voltage. In particular, the magnetoconductance at 10 MHz in a bipolar device was measured to be 4.5% at B = 30 mT. For bipolar devices we found that the frequency-dependent response of the device admittance to the small magnetic field is identical to the response of the admittance to a small increase in the bias voltage in zero magnetic field. We also found that the admittance of unipolar diodes does not depend on magnetic field.

Djidjou, Thaddee K.; Basel, Tek; Rogachev, Andrey

2012-07-01

27

Admittance of multiterminal quantum Hall conductors at kilohertz frequencies  

SciTech Connect

We present an experimental study of the low frequency admittance of quantum Hall conductors in the [100?Hz, 1?MHz] frequency range. We show that the frequency dependence of the admittance of the sample strongly depends on the topology of the contacts connections. Our experimental results are well explained within the Christen and Büttiker approach for finite frequency transport in quantum Hall edge channels taking into account the influence of the coaxial cables capacitance. In the Hall bar geometry, we demonstrate that there exists a configuration in which the cable capacitance does not influence the admittance measurement of the sample. In this case, we measure the electrochemical capacitance of the sample and observe its dependence on the filling factor.

Hernández, C. [Departamento de Física, Universidad Militar Nueva Granada, Carrera 11 101-80 Bogotá D.C. (Colombia); Consejo, C.; Chaubet, C., E-mail: christophe.chaubet@univ-montp2.fr [Université Montpellier 2, Laboratoire Charles Coulomb UMR5221, F-34095 Montpellier, France and CNRS, Laboratoire Charles Coulomb UMR5221, F-34095 Montpellier (France); Degiovanni, P. [Université de Lyon, Fédération de Physique Andrée Marie Ampère, CNRS, Laboratoire de Physique de l'Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon Cedex 07 (France)

2014-03-28

28

Transition metal oxides as charge injecting layer for admittance spectroscopy  

NASA Astrophysics Data System (ADS)

Admittance spectroscopy is a simple yet powerful tool to determine the carrier mobility of organic compounds. One requirement is to have an Ohmic contact for charge injection. By employing a thin interfacial layer of tungsten oxide, or molybdenum oxide we have found a possibility to efficiently inject holes into organic materials with a deep highest occupied molecular orbital level down to 6.3eV. These results considerably enhance the application range of the admittance spectroscopy method. The measured data are in excellent agreement with data obtained by the time-of-flight technique.

Hoping, M.; Schildknecht, C.; Gargouri, H.; Riedl, T.; Tilgner, M.; Johannes, H.-H.; Kowalsky, W.

2008-05-01

29

CHARACTERIZATION OF A SPONTANEOUSLY TRANSFORMED CHICKEN MONONUCLEAR CELL LINE  

Technology Transfer Automated Retrieval System (TEKTRAN)

We describe the characterization of a spontaneously transformed chicken monocytic cell line that developed as a single colony of cells in a heterophil culture that was inadvertently left in the incubator over a period of 25 days. These cells, hitherto named HTC, grow efficiently at both 37 C or 41 C...

30

Molecular Characterization of Spontaneous Mesenchymal Stem Cell Transformation  

PubMed Central

Background We previously reported the in vitro spontaneous transformation of human mesenchymal stem cells (MSC) generating a population with tumorigenic potential, that we termed transformed mesenchymal cells (TMC). Methodology/Principal Findings Here we have characterized the molecular changes associated with TMC generation. Using microarrays techniques we identified a set of altered pathways and a greater number of downregulated than upregulated genes during MSC transformation, in part due to the expression of many untranslated RNAs in MSC. Microarray results were validated by qRT-PCR and protein detection. Conclusions/Significance In our model, the transformation process takes place through two sequential steps; first MSC bypass senescence by upregulating c-myc and repressing p16 levels. The cells then bypass cell crisis with acquisition of telomerase activity, Ink4a/Arf locus deletion and Rb hyperphosphorylation. Other transformation-associated changes include modulation of mitochondrial metabolism, DNA damage-repair proteins and cell cycle regulators. In this work we have characterized the molecular mechanisms implicated in TMC generation and we propose a two-stage model by which a human MSC becomes a tumor cell. PMID:18167557

Rubio, Daniel; Garcia, Silvia; Paz, Maria F.; De la Cueva, Teresa; Lopez-Fernandez, Luis A.; Lloyd, Alison C.; Garcia-Castro, Javier; Bernad, Antonio

2008-01-01

31

EE 581 Power Systems Admittance Matrix: Direct and Iterative solutions,  

E-print Network

EE 581 Power Systems Admittance Matrix: Direct and Iterative solutions, Sensitivity #12;Overview: I. Interchange two rows II. Multiply a row by a nonzero real number III. Replace a row by its sum with a multiple of another row #12;Chapter 6.1: Gaussian Elimination Solution for row two: #12;Chapter 6

Wedeward, Kevin

32

The Power Flow Equations 1.0 The Admittance Matrix  

E-print Network

1 The Power Flow Equations 1.0 The Admittance Matrix Current injections at a bus are analogous to power injections. The student may have already been introduced to them in the form of current sources 2423242321221 1413121413121 yyyyyyy yyyyyyy yyyyyyy yyyyyyy Y (6) Denoting the element in row i, column j

McCalley, James D.

33

Enforcing passivity for admittance matrices approximated by rational functions  

Microsoft Academic Search

A linear power system component can be included in a transient simulation as a terminal equivalent by approximating its admittance matrix Y by rational functions in the frequency domain. Physical behavior of the resulting model entails that it should absorb active power for any set of applied voltages, at any frequency. This requires the real part of Y to be

Bjørn Gustavsen; Adam Semlyen

2001-01-01

34

EE 581 Power Systems Admittance Matrix: Development, Direct and Iterative  

E-print Network

of calculations, admittance is used (Y) Ohm's Law: V=IR Complex: V=IZ = 1 = (Siemens) is symmetric Equations Development: Models can be solved using either nodal (bus) analysis or port analysis Nodal analysis much easier to use than loop equations Nodal analysis used by computer programs For ease

Wedeward, Kevin

35

Characterizing seismic time series using the discrete wavelet transform  

SciTech Connect

The discrete wavelet transform (DWT) has potential as a tool for supplying discriminatory attributes with which to characterize or cluster groups of seismic traces in reservoir studies. The wavelet transform has the great advantage over the Fourier transform in being able to better localize changes. The multiscale nature and structure of the DWT leads to a method of display which highlights this and allows comparison of changes in the transform with changing data. Many different sorts of wavelet exist and it is found that the quality of reconstruction of a seismic trace wavelet exist and it is found that the quality of reconstruction of a seismic trace segment, using some of the coefficients, is dependent on the choice of wavelet, which leads us to consider choosing a wavelet under a best reconstruction criterion. Location shifts, time zero uncertainties, are also shown to affect the transform, as do truncations, resampling, etc. Using real data, examples of utilizing the DWT coefficients as attributes for whole trace segments or fractional trace segments are given. Provided the DWT is applied consistently, for example with a fixed wavelet, and non-truncated data, the transform produces useful results. Care must be exercised if it is applied to data of different lengths. However, as the algorithm is refined and improved in the future, the DWT should prove increasingly useful.

Grubb, H.J.; Walden, A.T. [Imperial College of Science, Technology and Medicine, London (United Kingdom). Dept. of Mathematics] [Imperial College of Science, Technology and Medicine, London (United Kingdom). Dept. of Mathematics

1997-03-01

36

Design and characterization of piezoelectric transformers for high power applications  

Microsoft Academic Search

A piezoelectric transformer (PT) is an electro-mechanical device that transfers electrical energy through a mechanical vibration at its resonance frequency. To improve the piezoelectric transformers in term of high density of transfer power, two types of piezoelectric transformers, a laminated piezoelectric transformer and an unipoled disk piezoelectric transformer, with radial extensional vibration mode were studied. For the laminated piezoelectric transformer,

Pitak Laoratanakul

2002-01-01

37

Speed-accuracy characteristics of human-machine cooperative manipulation using virtual fixtures with variable admittance.  

PubMed

This work explores the effect of virtual fixture admittance on the performance, defined by error and time, of task execution with a human-machine cooperative system. A desired path is obtained using computer vision, and virtual fixtures for assistance in planar path following were implemented on an admittance-controlled robot. The admittance controller uses a velocity gain, so that the speed of the robot is proportional to the force applied by the operator. The level of virtual fixture guidance is determined by the admittance ratio, which is the ratio of the admittance gain of the force components orthogonal to the path to the gain of the force components parallel to the path. In Experiment 1, we found a linear relationship between admittance ratio and performance. In Experiment 2, we examined the effect of admittance ratio on the performance of three tasks: path following, off-path targeting, and obstacle avoidance. An algorithm was developed to select an appropriate admittance ratio based on the nature of the task. Automatic admittance ratio tuning is recommended for next-generation virtual fixtures. Actual or potential applications of this research include surgery, assembly, and manipulation at the macro and micro scales. PMID:15573549

Marayong, Panadda; Okamura, Allison M

2004-01-01

38

PEDOT:PSS polymeric conducting anode for admittance spectroscopy  

Microsoft Academic Search

The carrier mobilities of two hole transporting organic materials were evaluated by admittance spectroscopy (AS). The materials were 4,4?,4?-tris{N,-(3-methylphenyl)-N-phenylamino}triphenylamine (m-MTDATA) and N,N?-diphenyl-N,N?-bis(1,1?-biphenyl)-4,4?-diamine (NPB). They were sandwiched in a configuration of anode\\/organic material\\/cathode. The anode was either indium-tin-oxide (ITO) or poly(3,4-ethylenedioxythiophene) doped with polystrenesulphonic acid (PEDOT:PSS). It is shown that PEDOT:PSS can, respectively, form Ohmic and quasi-Ohmic contact with m-MTDATA and

S. W. Tsang; S. C. Tse; K. L. Tong; S. K. So

2006-01-01

39

Impedance-admittance regression analysis of magnetotelluric fields  

NASA Astrophysics Data System (ADS)

The paper is devoted to the development of the theory of magnetotelluric field processing. A new method is proposed for complete consistent robust impedance-admittance regression estimation. This approach eliminates divergences between results obtained by independent solution of linear systems for the determination of impedance and admittance matrices and, moreover, is a good stabilizer of solution. Formulas for statistical estimates of results obtained by this method are derived. The theory developed in the paper is based on a linear algebraic approach. The regression problem is analyzed in a linear complex space with a nonrigidly specified metric. The metric of the solution space is formed concurrently with the solution of the problem on the basis of currently processed time series. All statistical estimations of results are performed in the metric obtained as a consequence of the solution and, in this sense, are optimal. The full regression model is effective for diagnosing the presence of electromagnetic fields that cannot be completely reduced to the plane wave approximation. the possibilities of the regression estimation are considered in detail on the basis of correlation analysis applied to sets of spectral components of electromagnetic fields.

Moskovskaya, L. F.

2007-02-01

40

PID Admittance Control for an Upper Limb Exoskeleton Wen Yu, Jacob Rosen, Xiaoou Li  

E-print Network

PID Admittance Control for an Upper Limb Exoskeleton Wen Yu, Jacob Rosen, Xiaoou Li Abstract-- The unique exoskeleton system (EXO-UL7) in UCSC is controlled in two levels. The lower-level uses standard a model-based impedance/admittance control when the model of the exoskeleton is unavailable. In this paper

Rosen, Jacob

41

High Power Piezoelectric Characterization for Piezoelectric Transformer Development  

NASA Astrophysics Data System (ADS)

The major goal was to develop characterization techniques to identify and define guidelines to manufacture high power density actuators. We particularly aim at improving the strengths of piezoelectric transformers, namely the high efficiency, ease of manufacturing, low electromagnetic noise, and high power to weight ratio resulting in an adaptor application by identifying material limitations, geometrical limitations and offer guidelines to counter drawbacks limiting the power density. There are 3 losses present in piezoelectrics. Namely dielectric, elastic and piezoelectric losses. These losses can be calculated using mechanical quality factors of the resonating piezoelectric actuator. But in order to calculate all three losses, the mechanical quality factor for resonance and anti resonance need to be measured. Although the mechanical quality factor for resonance is conventionally measured, measurements in antiresonance have been ignored. Since there was no unique measurement technique to address antiresonance and resonance Q in one single sweep, in this study constant vibration velocity method was developed. During the constant vibration velocity measurement, the input electrical energy is monitored and significant differences between resonance and antiresonance drives are observed. For the same output work (identical vibration velocity) significant differences in the losses were observed. Thermographic images have shown increasing temperature differences for resonance and antiresonance nodal point temperatures, with higher vibration velocities. The theoretical evaluation identified the difference observed in the mechanical quality factors at resonance and antiresonance to stem from the piezoelectric loss. In order to investigate losses in the absence of thermal effects a transient characterization technique was adopted. The burst technique, originally developed for characterization of the mechanical quality factor at resonance, has been modified with a switch circuit to leave the resonator in an open circuit condition. The newly introduced open circuits burst have resulted in antiresonance quality factor measurements along with resonance quality factors in a "non-heating" sample. In this technique too, resonance and antiresonance losses showed significant difference. Resonance burst mode characterizations at elevated ambient temperatures have shown that the lower vibration velocity mechanical quality factors appear to be more sensitive to the ambient temperature. Design criteria's to produce the most power dense structure were investigated. Common device shapes were investigated to see which one does enhance the power density of the piezoelectric device. Disk shaped piezoelectric actuators have proven to have lower matching impedances and higher, farther persisting mechanical quality factors with respect to vibration velocities. In order to achieve identical power level, plate shaped samples will have been to strain ~3.5 times more than disk shaped samples. Thus the most power dense structure has been concluded to be a disk shape ~1W/cm3 Once the actuators shape was fixed, further design on structure were conducted with (c)ATILA finite element method. For the transformer application, the design considered following key factors; 1-Controlling the output impedance by optimizing number of layers and layer thicknesses of the multilayer and 2- Evaluation of various electrodes and their affect on high power performance was evaluated. As the thickness of active layers decreased, the number of electrode layers increases. This increase in the metal to piezoelectric ratio and the relative increase in the electrode resistance under high current loads, both will have to be accounted for. Thus; with the piezoelectric composition and the device structure optimized, the research input electrical power. Once the actuators shape was fixed, further design on structure were conducted with (c)ATILA finite element method. For the transformer application, the design considered following key factors; 1-Controlling the output imped

Ural, Seyit O.

42

Admittance Selection Conditions for Frictionless Force-Guided Assembly of Polyhedral Parts in Two Single-Point Principal Contacts  

Microsoft Academic Search

The admittance of a manipulator can be used to improve robotic assembly. If properly selected, the admittance will regulate a contact force and use it to guide the parts to proper positioning. In previous work, procedures for selecting the appropriate admittance for single principal contact (PC) cases were identified. This paper extends this research for some of the two PC

Shuguang Huang; Joseph M. Schimmels

2008-01-01

43

Design and characterization of a signal insulation coreless transformer integrated in a CMOS gate driver chip  

E-print Network

Design and characterization of a signal insulation coreless transformer integrated in a CMOS gate transformer integrated in a CMOS silicon die together with the gate driver and other required functions frequency through the coreless transformer. The chosen design methodology will be explained and experimental

Paris-Sud XI, Université de

44

Quality control of dairy products using single frequency admittance measurements  

NASA Astrophysics Data System (ADS)

A reusable device for the detection of adulteration in dairy products such as milk and cream has been developed. The ac electrical admittance spectra of different samples have been studied using both uncoated and alkyl mercaptan-coated gold electrodes. Uncoated gold electrodes exhibited a polarization at around 250 Hz for full fat milk, while mercaptan-coated gold electrodes showed a similar effect at around 2 kHz. The characteristics at 100 kHz and 8 °C for all skimmed milk samples revealed a linear decrease in conductance with increasing water content over the entire range of water concentration. In contrast, the conductance of full fat milk, single and double cream, showed a linear decrease only at added water concentration higher than 6%. At lower concentrations, these dairy products exhibited anomalous conductivity maxima.

Mabrook, M. F.; Darbyshire, A. M.; Petty, M. C.

2006-02-01

45

Automatically calibrating admittances in KATE's autonomous launch operations model  

NASA Astrophysics Data System (ADS)

This report documents a 1000-line Symbolics LISP program that automatically calibrates all 15 fluid admittances in KATE's Autonomous Launch Operations (ALO) model. (KATE is Kennedy Space Center's Knowledge-based Autonomous Test Engineer, a diagnosis and repair expert system created for use on the Space Shuttle's various fluid flow systems.) As a new KATE application, the calibrator described here breaks new ground for KSC's Artificial Intelligence Lab by allowing KATE to both control and measure the hardware she supervises. By automating a formerly manual process, the calibrator: (1) saves the ALO model builder untold amounts of labor; (2) enables quick repairs after workmen accidently adjust ALO's hand valves; and (3) frees the modeler to pursue new KATE applications that previously were too complicated. Also reported are suggestions for enhancing the program: (1) to calibrate ALO's TV cameras, pumps, and sensor tolerances; and (2) to calibrate devices in other KATE models, such as the shuttle's LOX and Environment Control System (ECS).

Morgan, Steve

1992-09-01

46

Automatically calibrating admittances in KATE's autonomous launch operations model  

NASA Technical Reports Server (NTRS)

This report documents a 1000-line Symbolics LISP program that automatically calibrates all 15 fluid admittances in KATE's Autonomous Launch Operations (ALO) model. (KATE is Kennedy Space Center's Knowledge-based Autonomous Test Engineer, a diagnosis and repair expert system created for use on the Space Shuttle's various fluid flow systems.) As a new KATE application, the calibrator described here breaks new ground for KSC's Artificial Intelligence Lab by allowing KATE to both control and measure the hardware she supervises. By automating a formerly manual process, the calibrator: (1) saves the ALO model builder untold amounts of labor; (2) enables quick repairs after workmen accidently adjust ALO's hand valves; and (3) frees the modeler to pursue new KATE applications that previously were too complicated. Also reported are suggestions for enhancing the program: (1) to calibrate ALO's TV cameras, pumps, and sensor tolerances; and (2) to calibrate devices in other KATE models, such as the shuttle's LOX and Environment Control System (ECS).

Morgan, Steve

1992-01-01

47

Use of paravascular admittance waveforms to monitor relative change in arterial blood pressure  

NASA Astrophysics Data System (ADS)

Non-invasive methods to monitor ambulatory blood pressure often have limitations that can affect measurement accuracy and patient adherence [1]. Minimally invasive measurement of a relative blood pressure surrogate with an implantable device may provide a useful chronic diagnostic and monitoring tool. We assessed a technique that uses electrocardiogram and paravascular admittance waveform morphology analysis to one, measure a time duration (vascular tone index, VTI in milliseconds) change from the electrocardiogram R-wave to admittance waveform peak and two, measure the admittance waveform minimum, maximum and magnitude as indicators of change in arterial compliance/distensibility or pulse pressure secondary to change in afterload. Methods: Five anesthetized domestic pigs (32 ± 4.2 kg) were used to study the effects of phenylephrine (1-5 ug/kg/min) on femoral artery pressure and admittance waveform morphology measured with a quadrapolar electrode array catheter placed next to the femoral artery to assess the relative change in arterial compliance due to change in peripheral vascular tone. Results: Statistical difference was observed (p < 0.05) comparing baseline VTI to phenylephrine VTI (246 ± .05 ms to 320 ± .07 ms) and baseline admittance waveform maximum to phenylephrine admittance waveform maximum (0.0148 ± .002 siemens to 0.0151 ± .002 siemens). Conclusion: Chronic minimally invasive admittance measurement techniques that monitor relative change in blood pressure may be suitable for implantable devices to detect progression of cardiovascular disease such as hypertension.

Zielinski, Todd M.; Hettrick, Doug; Cho, Yong

2010-04-01

48

Physiological characterization of natural transformation in Acinetobacter calcoaceticus.  

PubMed

Acinetobacter calcoaceticus BD413 develops competence for natural transformation immediately after the start of the exponential growth-phase and remains competent up to e few hours into the stationary phase, after which competence gradually declines. The transformation frequencies obtained strongly depend on the kind of transforming DNA and the incubation time with DNA. Up to 25% of the cells in a culture can be transformed. DNA uptake in Acinetobacter does not display sequence specificity, is Mg(2+)-, Mn(2+)- or Ca(2+)-dependent and is uncoupler sensitive. The transforming DNA enters the cells in single-stranded form. These properties constitute a unique combination, not previously observed in other bacteria, and make A. caloaceticus ideally suited for detailed studies of the bioenergetics of DNA translocation. PMID:8436948

Palmen, R; Vosman, B; Buijsman, P; Breek, C K; Hellingwerf, K J

1993-02-01

49

Analysis of bridge admittance of plucked string instruments in the high frequency range  

E-print Network

) by the musician, the vibration of the string is transmitted to the soundboard via the bridge. The measurementAnalysis of bridge admittance of plucked string instruments in the high frequency range Benjamin

Paris-Sud XI, Université de

50

Stability analysis of converter-grid interaction using the converter input admittance  

Microsoft Academic Search

A grid-connected power electronic converter can cause local instabilities when interacting other subsystems-particularly poorly damped resonances-that are electrically nearby. However, oscillations at a certain frequency cannot build up due to the converter if its differential input admittance has positive conductance (real part) at that frequency, since power is then dissipated. Input-admittance expressions for a voltage-source converter are derived in this

Lennart Harnefors; Massimo Bongiorno; Stefan Lundberg

2007-01-01

51

CHARACTERIZING MODERN AND FOSSIL GYMNOSPERM EXUDATES USING MICRO-FOURIER TRANSFORM INFRARED SPECTROSCOPY  

E-print Network

CHARACTERIZING MODERN AND FOSSIL GYMNOSPERM EXUDATES USING MICRO-FOURIER TRANSFORM INFRARED spectroscopy have direct implications for the assessment of the fossil potential and the chemotaxonomic interpretation of modern and fossil gymnosperm exudates. Keywords: chemotaxonomy, plant resin, gum, conifers

Wolfe, Alexander P.

52

CHARACTERIZATION OF LYMPHOCYTE TRANSFORMATION INDUCED BY ZINC IONS  

Microsoft Academic Search

Lymphocyte cultures from all normal human adults are stimulated by zinc ions to increase DNA and RNA synthesis and undergo blast transformation. Optimal stimulation occurs at 0.1 mM Zn ++. Examination of the effects of other divalent cations reveals that 0.01 mM Hg ++ also stimulates lymphocyte DNA synthesis. Ca ++ and Mg ++ do not affect DNA synthesis in

NATHAN A. BERGER; MARIE SKINNER

1974-01-01

53

Global Admittance Estimates of Elastic and Crustal Thickness of Venus: Results from Top, Hot Spot, and Bottom Loading Models  

NASA Technical Reports Server (NTRS)

We have calculated admittance spectra using the spatio-spectral method [14] for Venus by moving the central location of the spectrum over a 1 grid, create 360x180 admittance spectra. We invert the observed admittance using top-loading (TL), hot spot (HS), and bottom loading (BL) models, resulting in elastic, crustal, and lithospheric thickness estimates (Te, Zc, and Zl) [0]. The result is a global map for interpreting subsurface structure. Estimated values of Te and Zc concur with previous TL local admittance results, but BL estimates indicate larger values than previously suspected.

Smrekar, S. E.; Anderson, F. S.

2005-01-01

54

Admittance detector for high impedance systems: design and applications.  

PubMed

We describe an admittance detector for high impedance systems (small capillary bore and/or low solution specific conductance). Operation in the low frequency range (?1 kHz, much lower than most relevant publications) provides optimum response to conductance changes in capillaries ?20 ?m in bore. The detector design was based on studies described in a preceding companion paper ( Zhang, M.; Stamos, B. N.; Amornthammarong, N.; Dasgupta, P. K. Anal. Chem. 2014, 8 , DOI 10.1021/ac503245a.). The highest S/N for detecting 100 ?M KCl (5.5 ?M peak concentration, ?0.8 ?S/cm) injected into water flowing through a capillary of 7.5 ?m inner radius (r) was observed at 500-750 Hz. A low bias current operational amplifier in the transimpedance configuration permitted high gain (1 V/nA) to measure pA-nA level currents in the detection cell. Aside from an oscillator, an offset-capable RMS-DC converter formed the complete detection circuitry. Limits of detection (LODs) of KCl scaled inversely with the capillary cross section and were 2.1 and 0.32 ?M injected KCl for r = 1 and 2.5 ?m capillaries, respectively. When used as a detector on an r = 8 ?m bore poly(methyl methacrylate) capillary in a split effluent stream from a suppressed ion chromatograph, the LOD was 27 nM bromide (Vex 22 V p-p), compared to 14 nM observed with a commercial bipolar pulse macroscale conductivity detector with an actively thermostated cell. We also show applications of the detector in electrophoresis in capillaries with r = 1 and 2.5 ?m. Efficient heat dissipation permits high concentrations of the background electrolyte and sensitive detection because of efficient electrostacking. PMID:25354912

Zhang, Min; Stamos, Brian N; Dasgupta, Purnendu K

2014-12-01

55

Isolation and characterization of an anaerobic chlorophenol-transforming bacterium.  

PubMed Central

An obligately anaerobic bacterium which transforms several chlorinated phenols was isolated. Dechlorination of the substituents ortho to the phenolic OH group was preferred, while removal of a meta-substituted chlorine was observed only with 3,5-dichlorophenol. The bacterium was a gram-positive, endospore-forming, motile, slightly curved rod. Sulfate was not reduced. Nitrate was reduced via nitrite to ammonium. The bacterium is related to the genus Clostridium. The highest growth rate was obtained in a medium containing pyruvate and yeast extract. Pyruvate supported growth as the sole source of carbon, and the fermentation of pyruvate produced almost equimolar amounts of acetate. Images PMID:1444400

Madsen, T; Licht, D

1992-01-01

56

Structural Characterization of Carbohydrates by Fourier Transform Tandem Mass Spectrometry  

PubMed Central

Fourier transform tandem mass spectrometry (MS/MS) provides high mass accuracy, high sensitivity, and analytical versatility and has therefore emerged as an indispensable tool for structural elucidation of biomolecules. Glycosylation is one of the most common posttranslational modifications, occurring in ~50% of proteins. However, due to the structural diversity of carbohydrates, arising from non-template driven biosynthesis, achievement of detailed structural insight is highly challenging. This review briefly discusses carbohydrate sample preparation and ionization methods, and highlights recent developments in alternative high-resolution MS/MS strategies, including infrared multiphoton dissociation (IRMPD), electron capture dissociation (ECD), and electron detachment dissociation (EDD), for carbohydrates with a focus on glycans and proteoglycans from mammalian glycoproteins. PMID:22389641

Zhou, Wen; Håkansson, Kristina

2012-01-01

57

Experimental Characterization of Hybrid Temperature and Frequency Effects on the Performance of Transformers on Silicon Substrate  

Microsoft Academic Search

We have performed an experimental characterization of hybrid temperature and frequency effects on the performance of on-chip square transformers. Using measured two-port S-parameters at different temperatures, we extracted and compared the maximum available gain$G_max$and fractional power loss$P_ loss$in each of three transformers (with turn numbers of$N = 2, 3$, and$4$of the primary and secondary spirals, respectively). We found that, as

Wen-Yan Yin; Shi Jinglin; Jun-Fa Mao; Le-Wei Li

2006-01-01

58

Synthesis and characterization of JBW structure and its thermal transformation  

SciTech Connect

In this paper, JBW zeolite prepared from Egyptian kaolin was investigated by means of XRD, IR, SEM, EDX and ion exchange of some heavy metals. Adsorption isotherms were used to investigate the structure and properties of the prepared zeolite. XRD analysis showed that the JBW was a pure crystalline phase with orthorhombic crystal symmetry. Thermal treatment showed that the JBW transformed into the It-Carn phase at 1000 Degree-Sign C through an intermediate crystalline alumino silicate phase. SEM images showed that the JBW crystallised in a cylindrical shape. However, spherical agglomerates were observed at lower magnifications. The ion exchange isotherms with Cu{sup 2+}, Ni{sup 2+} and Co{sup 2+} were found to follow a Freundlich isotherm. In addition, it shows higher affinity towards Cu{sup 2+} than other ions. - Graphical abstract: JBW zeolite structure was prepared from Egyptian kaolin and characterised. XRD analysis showed that the JBW was a pure crystalline phase with orthorhombic crystal symmetry. Thermal treatment showed that the JBW transformed into the It-Carn phase at 1000 Degree-Sign C through an intermediate crystalline alumino silicate phase. Highlights: Black-Right-Pointing-Pointer Egyptian kaolin was successfully used to prepare pure phase of JBW Structure. Black-Right-Pointing-Pointer JBW is stable till <300 Degree-Sign C. Black-Right-Pointing-Pointer JBW phase crystallizes as cylindrical shape but agglomerates in a Nano spherical shape. Black-Right-Pointing-Pointer The ion exchange isotherms of Cu{sup 2+}, Ni{sup 2+}, and Co{sup 2+} followed up Freundlich isotherm. Black-Right-Pointing-Pointer Selectivity towards Cu{sup 2+} is much higher than Co{sup 2+} or Ni{sup 2+}.

Hegazy, Eman Z., E-mail: ehegazy77@yahoo.com [Chemistry Department, Faculty of Science, King Abdul Aziz University, Jeddah (Saudi Arabia); National research Centre, Cairo (Egypt); Kosa, Samia A., E-mail: skousah@kau.edu.sa [Chemistry Department, Faculty of Science, King Abdul Aziz University, Jeddah (Saudi Arabia); Abd El Maksod, Islam Hamdy, E-mail: islam_9000@yahoo.com [Chemistry Department, Faculty of Science, King Abdul Aziz University, Jeddah (Saudi Arabia); National research Centre, Cairo (Egypt)

2012-12-15

59

Effects of wall admittance changes on duct transmission and radiation of sound.  

NASA Technical Reports Server (NTRS)

This paper is concerned with the effect of changes in duct wall acoustic properties on the transmission of sound through ducts. Two special problems are considered. The first problem is that of a rectangular infinite-length duct with airflow and a single change in duct wall acoustic admittance. The second problem is that of an axisymmetric field in a finite circular duct without airflow and with an arbitrary number of duct wall acoustic admittance changes. Results for the first problem show the effect of wall admittance change and flow on the acoustic power transmission within the duct. Results for the second problem show the interactive effects of multiple duct liner sections on power radiated from a finite duct.

Lansing, D. L.; Zorumski, W. E.

1973-01-01

60

A biotelemetric device for measurement of left ventricular pressure-volume loops using the admittance technique in conscious, ambulatory rats  

Microsoft Academic Search

This paper presents the design, construction and testing of a device to measure pressure-volume loops in the left ventricle of conscious, ambulatory rats. Pressure is measured with a standard sensor, but volume is derived from data collected from a tetrapolar electrode catheter using a novel admittance technique. There are two main advantages of the admittance technique to measure volume. First,

Karthik Raghavan; Marc D. Feldman; John E. Porterfield; Erik R. Larson; J. Travis Jenkins; Daniel Escobedo; John A. Pearce; Jonathan W. Valvano

2011-01-01

61

Analytical ultrasonics for characterization of metallurgical microstructures and transformations  

NASA Astrophysics Data System (ADS)

The application of contact (piezoelectric) and noncontact (laser generation and detection) ultrasonic techniques for dynamic investigation of precipitation hardening processes in aluminum alloys, as well as crystallization and phase transformation in rapidly solidified amorphous and microcrystalline alloys is discussed. From the variations of the sound velocity and attenuation the precipitation mechanism and kinetics were determined. In addition, a correlation was established between the observed changes in the velocity and attenuation and the mechanical properties of age-hardenable aluminum alloys. The behavior of the elastic moduli, determined ultrasonically, were found to be sensitive to relaxation, crystallization and phase decomposition phenomena in rapidly solidified metallic glasses. Analytical ultrasonics enables determination of the activation energies and growth parameters of the reactions. Therefrom theoretical models can be constructed to explain the changes in mechanical and physical properties upon heat treatment of glassy alloys. The composition dependence of the elastic moduli in amorphous Cu-Zr alloys was found to be related to the glass transition temperature, and consequently to the glass forming ability of these alloys. Dynamic ultrasonic analysis was found to be feasible for on-line, real-time, monitoring of metallurgical processes.

Rosen, M.

1986-01-01

62

TRANSFORMATION  

SciTech Connect

Transformation, which alters the genetic makeup of an individual, is a concept that intrigues the human imagination. In Streptococcus pneumoniae such transformation was first demonstrated. Perhaps our fascination with genetics derived from our ancestors observing their own progeny, with its retention and assortment of parental traits, but such interest must have been accelerated after the dawn of agriculture. It was in pea plants that Gregor Mendel in the late 1800s examined inherited traits and found them to be determined by physical elements, or genes, passed from parents to progeny. In our day, the material basis of these genetic determinants was revealed to be DNA by the lowly bacteria, in particular, the pneumococcus. For this species, transformation by free DNA is a sexual process that enables cells to sport new combinations of genes and traits. Genetic transformation of the type found in S. pneumoniae occurs naturally in many species of bacteria (70), but, initially only a few other transformable species were found, namely, Haemophilus influenzae, Neisseria meningitides, Neisseria gonorrheae, and Bacillus subtilis (96). Natural transformation, which requires a set of genes evolved for the purpose, contrasts with artificial transformation, which is accomplished by shocking cells either electrically, as in electroporation, or by ionic and temperature shifts. Although such artificial treatments can introduce very small amounts of DNA into virtually any type of cell, the amounts introduced by natural transformation are a million-fold greater, and S. pneumoniae can take up as much as 10% of its cellular DNA content (40).

LACKS,S.A.

2003-10-09

63

Theoretical modeling of a thickness-shear mode circular cylinder piezoelectric transformer.  

PubMed

We propose a piezoelectric transformer operating with thickness-shear modes of a circular cylinder and perform a theoretical analysis on the transformer. An exact solution from the three-dimensional equations of piezoelectricity is obtained. The output voltage, input admittance, and efficiency of the transformer are determined. The basic behaviors of the transformer are shown by numerical results. PMID:17375831

Yang, Jiashi; Chen, Ziguang; Hu, Yuantai

2007-03-01

64

Towards Efficient Automated Characterization of Irregular Histology Images via Transformation to Frieze-Like Patterns  

E-print Network

Towards Efficient Automated Characterization of Irregular Histology Images via Transformation to Frieze-Like Patterns ABSTRACT Histology is used in both clinical and research contexts as a highly equipment has enabled high-throughput digitization of high-resolution histology slides, the manual scoring

65

Characterization of fluids involved in the Gneiss-Charnockite transformation in Southern Kerala (India)  

NASA Technical Reports Server (NTRS)

The characterization of fluids involved in the gneiss-charnockite transformation in southern Kerala are discussed. Using a variety of techniques, including microthermometry, Raman laser probe analysis, and mass spectrometry, it was concluded that the CO2-rich, N2-bearing metamorphic fluids in these rocks were internally-derived rather than having been introduced by CO2-streaming.

Klatt, E.; Hoernes, S.; Raith, M.

1988-01-01

66

Admittance model for the shuttle remote manipulator system in four configurations. M.S. Thesis  

NASA Technical Reports Server (NTRS)

A possible scenario for robot task performance in space is to mount two small, dexterous arms to the end of the Shuttle Remote Manipulator System (SRMS). As these small robots perform tasks, the flexibility of the SRMS may cause unsuccessful task executions. In order to simulate the dynamic coupling between the SRMS and the arms, admittance models of the SRMS in four brakes locked configurations were developed. The admittance model permits calculation of the SRMS end-effector response due to end-effector disturbing forces. The model will then be used in conjunction with a Stewart Platform, a vehicle emulation system. An application of the admittance model was shown by simulating the disturbing forces using two SRMS payloads, the Dextrous Orbital Servicing System (DOSS) manipulator and DOSS carrying a 1000 lb. cylinder. Mode by mode comparisons were conducted to determine the minimum number of modes required in the admittance model while retaining dynamic fidelity. It was determined that for all four SRMS configurations studied, between 4 and 6 modes of the SRMS structure (depending on the excitation loads) were sufficient to retain tolerance of 0.01 inches and 0.01 deg. These tolerances correspond to the DOSS manipulator carrying no object. When the DOSS carries the 1000 lb. cylinder, between 15 and 20 modes were sufficient, approximately three or four times as many modes as for the unloaded case.

Papadopoulos, Loukas; Tolson, Robert H.

1993-01-01

67

Design of Redundant Drive Joint with adjustable stiffness and damping mechanism to improve joint admittance  

Microsoft Academic Search

Improving admittance of robotic joints is the key issue for making rehabilitation robots safe. This paper describes a design of redundant drive joint (RD-Joint) which allows greater flexibility in the design of robotic mechanisms. The design strategy of the RD-joint employs a systematic approach which consists of 1) adopting a redundant joint mechanism with internal kinematical redundancy to reduce effective

Yosuke Ikegami; Kiyoshi Nagai; Rui C. V. Loureiro; William S. Harwin

2009-01-01

68

The admittance of bare circular loop antennas in a dissipative medium  

Microsoft Academic Search

The normalized input admittance of thin bare circular loop antennas has been evaluated from the theory of T. T. Wu. Computations have been made for loops in air and in an infinite homogeneous isotropic dissipative medium. A comparison is also made with Storer's theory of the loop. Numerical results are given in the form of graphs for several wire sizes

R. King; D. Tingley

1964-01-01

69

Effects of Series Resistance and Inductance on Solar Cell Admittance Measurements(a)  

E-print Network

cells. The model circuit consists of a capacitance C in parallel with a resistance r circuit consisting of a capacitance (C) in parallel with a shunt resistance (r), with these in series admittance of a four-element circuit is calculated and compared with measurements on two typical CIGS solar

Scofield, John H.

70

Application of admittance spectroscopy to evaluate carrier mobility in organic charge transport materials  

E-print Network

of high efficiency organic light-emitting diodes OLEDs in 1980s has triggered extensive researchApplication of admittance spectroscopy to evaluate carrier mobility in organic charge transport AS and susceptance analysis in the determination of the charge-carrier mobility in an organic material. The complex

So, Shu K.

71

Admittance control for anti-islanding protection in modular grid-connected inverters  

Microsoft Academic Search

A major requirement for grid-connected power converters imposed by codes and standards is “anti-islanding” protection. When the grid connection is lost or otherwise stops functioning, the photovoltaic power converter is required to shut off to avoid “backfeed” into the local distribution network. This paper describes a “reverse PFC” admittance control that controls the output current of an inverter in response

Philip T. Krein; Trishan Esram

2010-01-01

72

Localization and Characterization of the Carbon Tetrachloride Transformation Activity of Pseudomonas sp. Strain KC  

PubMed Central

Previous research has established that Pseudomonas sp. strain KC rapidly transforms carbon tetrachloride (CT) to carbon dioxide (45 to 55%), a nonvolatile fraction (45 to 55%), and a cell-associated fraction ((equiv)5%) under denitrifying, iron-limited conditions. The present study provides additional characterization of the nonvolatile fraction, demonstrates that electron transfer plays a role in the transformation, and establishes the importance of both extracellular and intracellular factors. Experiments with (sup14)C-labeled CT indicate that more than one nonvolatile product is produced during CT transformation by strain KC. One of these products, accounting for about 20% of the [(sup14)C]CT transformed, was identified as formate on the basis of its elution time from an ion-exchange column, its boiling point, and its conversion to (sup14)CO(inf2) when incubated with formate dehydrogenase. Production of formate requires transfer of two electrons to the CT molecule. The role of electron transfer was also supported by experiments demonstrating that stationary-phase cells that do not transform CT can be stimulated to transform CT when supplemented with acetate (electron donor), nitrate (electron acceptor), or a protonophore (carbonyl cyanide m-chlorophenylhydrazone). The location of transformation activity was also evaluated. By themselves, washed cells did not transform CT to a significant degree. Occasionally, CT transformation was observed by cell-free culture supernatant, but this activity was not reliable. Rapid and reliable CT transformation was only obtained when washed whole cells were reconstituted with culture supernatant, indicating that both extracellular and intracellular factors are normally required for CT transformation. Fractionation of culture supernatant by ultrafiltration established that the extracellular factor or factors are small, with an apparent molecular mass of less than 500 Da. The extracellular factor or factors were stable after lyophilization to powder and were extractable with acetone. Addition of micromolar levels of iron inhibited CT transformation in whole cultures, but the level of iron needed to inhibit CT transformation was over 100-fold higher for washed cells reconstituted with a 10,000-Da supernatant filtrate. Thus, the inhibitory effects of iron are exacerbated by a supernatant factor or factors with a molecular mass greater than 10,000 Da. PMID:16534941

Dybas, M. J.; Tatara, G. M.; Criddle, C. S.

1995-01-01

73

Methods for detection and characterization of signals in noisy data with the Hilbert-Huang transform  

SciTech Connect

The Hilbert-Huang transform is a novel, adaptive approach to time series analysis that does not make assumptions about the data form. Its adaptive, local character allows the decomposition of nonstationary signals with high time-frequency resolution but also renders it susceptible to degradation from noise. We show that complementing the Hilbert-Huang transform with techniques such as zero-phase filtering, kernel density estimation and Fourier analysis allows it to be used effectively to detect and characterize signals with low signal-to-noise ratios.

Stroeer, Alexander; Cannizzo, John K.; Camp, Jordan B.; Gagarin, Nicolas [Laboratory for Gravitational Physics, Goddard Space Flight Center, Greenbelt, Maryland 20771 (United States); Starodub, Incorporated, 3504 Littledale Road, Kensington, Maryland, 20895 (United States)

2009-06-15

74

Molecular cloning and characterization of plastin, a human leukocyte protein expressed in transformed human fibroblasts.  

PubMed Central

The phosphoprotein plastin was originally identified as an abundant transformation-induced polypeptide of chemically transformed neoplastic human fibroblasts. This abundant protein is normally expressed only in leukocytes, suggesting that it may play a role in hemopoietic cell differentiation. Protein microsequencing of plastin purified from leukemic T lymphocytes by high-resolution two-dimensional gel electrophoresis produced eight internal oligopeptide sequences. An oligodeoxynucleotide probe corresponding to one of the oligopeptides was used to clone cDNAs from transformed human fibroblasts that encoded the seven other oligopeptides predicted for human plastin. Sequencing and characterization of two cloned cDNAs revealed the existence of two distinct, but closely related, isoforms of plastin--l-plastin, which is expressed in leukocytes and transformed fibroblasts, and t-plastin, which is expressed in normal cells of solid tissues and transformed fibroblasts. The leukocyte isoform l-plastin is expressed in a diverse variety of human tumor cell lines, suggesting that it may be involved in the neoplastic process of some solid human tumors. Images PMID:3211125

Lin, C S; Aebersold, R H; Kent, S B; Varma, M; Leavitt, J

1988-01-01

75

76 FR 31306 - Admittance to Practice and Roster of Registered Patent Attorneys and Agents Admitted to Practice...  

Federal Register 2010, 2011, 2012, 2013, 2014

...DEPARTMENT OF COMMERCE Patent and Trademark Office Admittance to Practice and Roster of Registered Patent Attorneys and Agents Admitted to Practice Before the United States Patent and Trademark Office (USPTO) (Proposed...

2011-05-31

76

Effect of Different Plasmon Active Metals on Admittance Loci Based Design of a Plasmonic Sensor  

NASA Astrophysics Data System (ADS)

A Kretschmann type plasmonic structure consisting of a fused silica glass prism, plasmon active metal film and dielectric sample has been investigated with the use of admittance loci method in attenuated total internal reflection mode. Different plasmon active metals have been used to study their effect on surface plasmon resonance (SPR) sensing (at 633 nm wavelength of He-Ne light) by admittance loci plots and also by corresponding SPR sensing curves. The performance of the plasmonic structure based on the choice of plasmon active metal has been discussed with the help of sensitivity and figure of merit plots giving emphasis on the dynamic range of the designed plasmonic structure. Simulations have been carried out in MATLAB 7.1 environment.

Brahmachari, Kaushik; Ray, Mina

2014-11-01

77

Adaptive Admittance Control: An Approach to Explicit Force Control in Compliant Motion  

Microsoft Academic Search

J'his paper addresses the problem of controlling a ma- ni)mlator in compliant motion while in contact with an environment having an unknown stiffness. Admittance control is used as an czplzczt force control sc})eme in which a force setpoint is specified and is tracked by the force compensator. Two adaptive PID and 1>1 force colnpcnsators arc propcrscd. The compensators ensure robust

Homayoun Seraji

1994-01-01

78

Left ventricular epicardial admittance measurement for detection of acute LV dilation  

PubMed Central

There are two implanted heart failure warning systems incorporated into biventricular pacemakers/automatic implantable cardiac defibrillators and tested in clinical trials: right heart pressures, and lung conductance measurements. However, both warning systems postdate measures of the earliest indicator of impending heart failure: left ventricular (LV) volume. There are currently no proposed implanted technologies that can perform LV blood volume measurements in humans. We propose to solve this problem by incorporating an admittance measurement system onto currently deployed biventricular and automatic implantable cardiac defibrillator leads. This study will demonstrate that an admittance measurement system can detect LV blood conductance from the epicardial position, despite the current generating and sensing electrodes being in constant motion with the heart, and with dynamic removal of the myocardial component of the returning voltage signal. Specifically, in 11 pigs, it will be demonstrated that 1) a physiological LV blood conductance signal can be derived; 2) LV dilation in response to dose-response intravenous neosynephrine can be detected by blood conductance in a similar fashion to the standard of endocardial crystals when admittance is used, but not when only traditional conductance is used; 3) the physiological impact of acute left anterior descending coronary artery occlusion and resultant LV dilation can be detected by blood conductance, before the anticipated secondary rise in right ventricular systolic pressure; and 4) a pleural effusion simulated by placing saline outside the pericardium does not serve as a source of artifact for blood conductance measurements. PMID:21148342

Porterfield, John E.; Larson, Erik R.; Jenkins, James T.; Escobedo, Daniel; Valvano, Jonathan W.; Pearce, John A.

2011-01-01

79

Admittance analysis in (PPE-PPV) polymer (AnE-PVstat) light emitting diodes  

NASA Astrophysics Data System (ADS)

In this work, admittance analysis of organic light emitting diode (OLED) (anode/active layer/cathode) was performed at room temperature within the frequency range of 1 kHz-1MHz to find out transport properties of both injected carriers from each side. Moreover, by proper chosen metals, electron or hole only OLED devices were prepared and the measurement was resumed to identify the governed transport path of injected carrier. Mobility of injected carriers followed the Poole-Frenkel type conduction mechanism and distinguished in the frequency range due to the difference of transit times in admittance measurement. Beginning of light output and onset of negative capacitance took place at the turn-on voltage (or flat band voltage), 1.8 V, which was the difference of energy band gap of polymer and two barrier offsets between metals and polymer. The proposed analytical model for admittance, derived for the frequency dependent space charge limited behavior leading negative capacitance issues, was applied on the measured data for the present OLED device.

Özdemir, Orhan; Mucur, Selin P.; Tekin, Emine; Boudiba, Sameh; Ulbricht, Christoph; Egbe, Daniel A. M.; Deneb Menda, U.; Kavak, Pelin Aydogan; Kutlu, Kubilay

2013-09-01

80

Microstructural characterization of transformable Fe-Mn alloys at different length scales  

SciTech Connect

The as-annealed and deformed Microstructure of transformable Fe-Mn alloys were, comprehensively, characterized over a wide range of length scales. Differential interference contrast optical metallography, combined with a tinting etching method, was employed to examine the grain morphology. A new specimen preparation method, involving electro-polishing and electro-etching, was developed for scanning electron microscopy and electron back-scattered diffraction analysis. This method leads to a very good imaging contrast and thus bridges the length scale gap between optical metallography and transmission electron microscopy. Moreover, it enables simultaneous scanning electron microscopy and electron backscatter diffraction analysis which allows correlations among morphology, crystal orientation and phase analysis in the length scale of microns. Transmission electron microscopy investigations were also made to evaluate the thermal and mechanical transformation products as well as defect structures.

Liang, X.; Wang, X. [Department of Materials Science and Engineering, McMaster University, 1280 Main St. W., Hamilton, Ontario, L8S 4L7 (Canada); Zurob, H.S., E-mail: zurobh@mcmaster.ca [Department of Materials Science and Engineering, McMaster University, 1280 Main St. W., Hamilton, Ontario, L8S 4L7 (Canada)

2009-11-15

81

Characterization of Solid State Phase Transformation in Continuously Heated and Cooled Ferritic Weld Metal  

SciTech Connect

Arc welding processes involve cooling rates that vary over a wide range (1-100 K/s). The final microstructire is thus a product of the heating and cooling cycles experienced by the weld in addition to the weld composition. It has been shown that the first phase to form under weld cooling conditions may not be that predicted by equilibrium calculations. The partitioning of different interstitial/substitutional alloying elements at high temperatures can dramatically affect the subsequent phase transformations. In order to understand the effect of alloying on phase transformation temperatures and final microstructures time-resolved X-ray diffraction technique has been successfully used for characterization. The work by Jacot and Rappaz on pearlitic steels provided insight into austenitization of hypoeutectic steels using a finite volume model. However there is very little work done on the effect of heating and cooling rates on the phase transformation paths in bainitic/martensitic steels and weld metals. Previous work on a weld with higher aluminum content, deposited with a FCAW-S process indicated that even at aluminum levels where the primary phase to solidify from liquid should be delta ferrite, non-equilibrium austenite was observed. The presence of inhomogeneity in composition of the parent microstructure has been attributed to differences in transformation modes, temperatures and microstructures in dual-phase, TRIP steels and ferritic welds. The objectives of the work included the identification of the stability regions of different phases during heating and cooling, differences in the effect of weld heating and cooling rates on the phase transformation temperatures, and the variation in phase fractions of austenite and ferrite in the two phase regions as a function of temperature. The base composition used for the present work is a Fe-1%Al-2%Mn-1%Ni-0.04%C weld metal. A pseudo-binary phase diagram shows the expected solidification path under equilibrium conditions. However, the effect of heating and cooling rates on the phase transformation path due to non-equilibrium partitioning of alloying elements cannot be predicted by equilibrium phase diagrams. Also, it is unclear if there is retention of delta ferrite to room temperature due to compositional or thermal effects. This would dramatically affect the austenite to ferrite transformation due to carbon and nitrogen enrichment in the austenite.

Narayana, B [Ohio State University, The, Columbus; Mills, Michael J. [Ohio State University, The, Columbus; Specht, Eliot D [ORNL; Santella, Michael L [ORNL; Babu, Sudarsanam Suresh [Ohio State University, The, Columbus

2010-12-01

82

Optical Fourier transform based in-plane vibration characterization for MEMS comb structure.  

PubMed

On-line and on-wafer characterizations of mechanical properties of Micro-Electro-Mechanical-System (MEMS) with efficiency are very important to the mass production of MEMS foundry in the near future. However, challenges still remain. In this paper, we present an in-plane vibration characterizing method for MEMS comb using optical Fourier transform (OFT). In the experiment, the intensity distribution at the focal plane was captured to characterize the displacement of the vibrator in the MEMS comb structure. A typical MEMS comb was tested to verify the principle. The shape and the movement of MEMS comb was imitated and tested to calibrate the measurement by using a spatial light modulator (SLM). The relative standard deviations (RSD) of the measured displacements were better than 5%, where the RSD is defined as the ratio of the standard deviation to the mean. It is convinced that the presented method is feasible for on-line and on-wafer characterizations for MEMS with great convenience, high efficiency and low cost. PMID:23482039

Gao, Yongfeng; Cao, Liangcai; You, Zheng; Zhao, Jiahao; Zhang, Zichen; Yang, Jianzhong

2013-02-25

83

Dynamic virtual fixture on the Euclidean group for admittance-type manipulator in deforming environments  

PubMed Central

Background In a deforming anatomic environment, the motion of an instrument suffers from complex geometrical and dynamic constraints, robot assisted minimally invasive surgery therefore requires more sophisticated skills for surgeons. This paper proposes a novel dynamic virtual fixture (DVF) to enhance the surgical operation accuracy of admittance-type medical robotics in the deforming environment. Methods A framework for DVF on the Euclidean Group SE(3) is presented, which unites rotation and translation in a compact form. First, we constructed the holonomic/non-holonomic constraints, and then searched for the corresponded reference to make a distinction between preferred and non-preferred directions. Second, different control strategies are employed to deal with the tasks along the distinguished directions. The desired spatial compliance matrix is synthesized from an allowable motion screw set to filter out the task unrelated components from manual input, the operator has complete control over the preferred directions; while the relative motion between the surgical instrument and the anatomy structures is actively tracked and cancelled, the deviation relative to the reference is compensated jointly by the operator and DVF controllers. The operator, haptic device, admittance-type proxy and virtual deforming environment are involved in a hardware-in-the-loop experiment, human-robot cooperation with the assistance of DVF controller is carried out on a deforming sphere to simulate beating heart surgery, performance of the proposed DVF on admittance-type proxy is evaluated, and both human factors and control parameters are analyzed. Results The DVF can improve the dynamic properties of human-robot cooperation in a low-frequency (0?~?40 rad/sec) deforming environment, and maintain synergy of orientation and translation during the operation. Statistical analysis reveals that the operator has intuitive control over the preferred directions, human and the DVF controller jointly control the motion along the non-preferred directions, the target deformation is tracked actively. Conclusions The proposed DVF for an admittance-type manipulator is capable of assisting the operator to deal with skilled operations in a deforming environment. PMID:24767578

2014-01-01

84

Measuring the complex admittance of a nearly isolated graphene quantum dot  

SciTech Connect

We measured the radio-frequency reflection spectrum of an on-chip reflection line resonator coupled to a graphene double quantum dot (DQD), which was etched almost isolated from the reservoir and reached the low tunnel rate region. The charge stability diagram of DQD was investigated via dispersive phase and magnitude shift of the resonator with a high quality factor. Its complex admittance and low tunnel rate to the reservoir was also determined from the reflected signal of the on-chip resonator. Our method may provide a non-invasive and sensitive way of charge state readout in isolated quantum dots.

Zhang, Miao-Lei; Wei, Da; Deng, Guang-Wei; Li, Shu-Xiao; Li, Hai-Ou; Cao, Gang; Tu, Tao; Xiao, Ming; Guo, Guang-Can; Guo, Guo-Ping, E-mail: gpguo@ustc.edu.cn [Key Laboratory of Quantum Information, Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Chinese Academy of Sciences, Hefei 230026 (China); Jiang, Hong-Wen [Department of Physics and Astronomy, University of California at Los Angeles, Los Angeles, California 90095 (United States)

2014-08-18

85

Admittance Test and Conceptual Study of a CW Positron Source for CEBAF  

SciTech Connect

A conceptual study of a Continuous Wave (CW) positron production is presented in this paper. The Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab (JLAB) operates with a CW electron beam with a well-defined emittance, time structure and energy spread. Positrons created via bremsstrahlung photons in a high-Z target emerge with a large emittance compared to incoming electron beam. An admittance study has been performed at CEBAF to estimate the maximum beam phase space area that can be transported in the LINAC and in the Arcs. A positron source is described utilizing the CEBAF injector electron beam, and directly injecting the positrons into the CEBAF LINAC.

Golge, Serkan [Department of Physics, Old Dominion University, Norfolk VA 23529 (United States); Hyde, Charles E. [Department of Physics, Old Dominion University, Norfolk VA 23529 (United States); Universite Blaise Pascal, Clermont-Ferrand (France); Freyberger, Arne [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States)

2009-09-02

86

A Multi-Function Force Sensing Instrument for Variable Admittance Robot Control in Retinal Microsurgery*  

PubMed Central

Robotic systems have the potential to assist vitreoretinal surgeons in extremely difficult surgical tasks inside the human eye. In addition to reducing hand tremor and improving tool positioning, a robotic assistant can provide assistive motion guidance using virtual fixtures, and incorporate real-time feedback from intraocular force sensing ophthalmic instruments to present tissue manipulation forces, that are otherwise physically imperceptible to the surgeon. This paper presents the design of an FBG-based, multi-function instrument that is capable of measuring mN-level forces at the instrument tip located inside the eye, and also the sclera contact location on the instrument shaft and the corresponding contact force. The given information is used to augment cooperatively controlled robot behavior with variable admittance control. This effectively creates an adaptive remote center-of-motion (RCM) constraint to minimize eye motion, but also allows the translation of the RCM location if the instrument is not near the retina. In addition, it provides force scaling for sclera force feedback. The calibration and validation of the multi-function force sensing instrument are presented, along with demonstration and performance assessment of the variable admittance robot control on an eye phantom. PMID:25383234

He, Xingchi; Balicki, Marcin; Gehlbach, Peter; Handa, James; Taylor, Russell; Iordachita, Iulian

2014-01-01

87

A Multi-Function Force Sensing Instrument for Variable Admittance Robot Control in Retinal Microsurgery.  

PubMed

Robotic systems have the potential to assist vitreoretinal surgeons in extremely difficult surgical tasks inside the human eye. In addition to reducing hand tremor and improving tool positioning, a robotic assistant can provide assistive motion guidance using virtual fixtures, and incorporate real-time feedback from intraocular force sensing ophthalmic instruments to present tissue manipulation forces, that are otherwise physically imperceptible to the surgeon. This paper presents the design of an FBG-based, multi-function instrument that is capable of measuring mN-level forces at the instrument tip located inside the eye, and also the sclera contact location on the instrument shaft and the corresponding contact force. The given information is used to augment cooperatively controlled robot behavior with variable admittance control. This effectively creates an adaptive remote center-of-motion (RCM) constraint to minimize eye motion, but also allows the translation of the RCM location if the instrument is not near the retina. In addition, it provides force scaling for sclera force feedback. The calibration and validation of the multi-function force sensing instrument are presented, along with demonstration and performance assessment of the variable admittance robot control on an eye phantom. PMID:25383234

He, Xingchi; Balicki, Marcin; Gehlbach, Peter; Handa, James; Taylor, Russell; Iordachita, Iulian

2014-05-01

88

Experimental characterization of shear transformation zones for plastic flow of bulk metallic glasses  

PubMed Central

We report experimental characterization of shear transformation zones (STZs) for plastic flow of bulk metallic glasses (BMGs) based on a newly developed cooperative shearing model [Johnson WL, Samwer K (2005) A universal criterion for plastic yielding of metallic glasses with a (T/Tg)2/3 temperature dependence. Phys Rev Lett 95: 195501]. The good agreement between experimental measurements and theoretical predictions in the STZ volumes provides compelling evidence that the plastic flow of metallic glasses occurs through cooperative shearing of unstable STZs activated by shear stresses. Moreover, the ductility of BMGs was found to intrinsically correlate with their STZ volumes. The experiments presented herein pave a way to gain a quantitative insight into the atomic-scale mechanisms of BMG mechanical behavior. PMID:18815377

Pan, D.; Inoue, A.; Sakurai, T.; Chen, M. W.

2008-01-01

89

Acoustic gravity waves during solar eclipses: Detection and characterization using wavelet transforms  

NASA Astrophysics Data System (ADS)

In the present contribution, we first propose a methodology that enables to detect wave-like structures propagating in ionosphere, by tracking the local maxima of the modulus of continuous complex wavelet transform coefficients with respect to heights. From the derivation of the phases of the wavelet transform, we measure the corresponding propagation parameters. These tools are applied to measurements collected by vertical ionospheric sounding at high-time resolution sampling regime (sampling periods ranged from 1 to 3 min) in the observatory Pr?honice (49.9N, 14.5E, Czech Republic). The aim of these experiments is to analyze the changes in the ionospheric plasma induced by three different solar eclipse events (total solar eclipses, 11 August 1999, 29 March 2006, and annular solar eclipse, 3 October 2005) and to detect and analyze the propagation of the generated acoustic gravity waves (AGWs). Second, injecting wave vector components measured from the data into the AGW propagation equations, we obtain a full description of the propagation of the waves. This enables us to differentiate AGWs from others wave-like oscillations and to discuss similarities and differences of the waves detected during these three particular events. These procedures also enabled us to detect acoustic waves. We believe that the methodology proposed here brings significant improvement in detecting and characterizing AGW propagations from empirical data and can be readily used in the ionosphere community.

Šauli, P.; Roux, S. G.; Abry, P.; Boška, J.

2007-12-01

90

Transformation twinning of Ni–Mn–Ga characterized with temperature-controlled atomic force microscopy  

PubMed Central

The magnetomechanical properties of ferromagnetic shape memory alloy Ni–Mn–Ga single crystals depend strongly on the twin microstructure, which can be modified through thermomagnetomechanical training. Atomic force microscopy (AFM) and magnetic force microscopy (MFM) were used to characterize the evolution of twin microstructures during thermomechanical training of a Ni–Mn–Ga single crystal. Experiments were performed in the martensite phase at 25 °C and in the austenite phase at 55 °C. Two distinct twinning surface reliefs were observed at room temperature. At elevated temperature (55 °C), the surface relief of one twinning mode disappeared while the other relief remained unchanged. When cooled back to 25 °C, the twin surface relief recovered. The relief persisting at elevated temperature specifies the positions of twin boundaries that were present when the sample was polished prior to surface characterization. AFM and MFM following thermomechanical treatment provide a nondestructive method to identify the crystallographic orientation of each twin and of each twin boundary plane. Temperature dependent AFM and MFM experiments reveal the twinning history thereby establishing the technique as a unique predictive tool for revealing the path of the martensitic and reverse transformations of magnetic shape memory alloys. PMID:20589105

Reinhold, Matthew; Watson, Chad; Knowlton, William B.; Müllner, Peter

2010-01-01

91

Energetic, enthusiastic and, by his own admittance, total-ly in love with hiswork, Bernard Slippers isa role model that  

E-print Network

parents and grandparents that instilled a love for nature in me." He remembers his grand- mother's rockEnergetic, enthusiastic and, by his own admittance, total- ly in love with hiswork, Bernard of adapted plants and animals of the desert. Further entrenching this were his father and grandfather's love

92

Self and mutual admittances of two identical circular loop antennas in a conducting medium and in air  

Microsoft Academic Search

The normalized self- and mutual admittances of two identical bare circular loop antennas have been evaluated when the loops are immersed in either air or an infinite homogeneous conducting medium. By decomposing the voltage and current into symmetric and antisymmetric components, the simultaneous integral equations for the distribution of current along the loop have been converted into a single integral

K. Iizuka; R. King

1966-01-01

93

Global Admittance Estimates of Elastic and Crustal Thickness of Venus: Preliminary Results from Top and Bottom Loading Models  

NASA Technical Reports Server (NTRS)

Initial elastic and crustal thickness estimates (Te and Zc) for a global set of local admittance inversions with a one degree spacing for Venus provide a global map for interpreting subsurface structure. Additional information is contained in the original extended abstract.

Anderson, F. S.; Smrekar, S. E.

2001-01-01

94

Sixteen-Year Change in Acoustic-Admittance Measures among Older Adults: Data from a Population-Based Study  

ERIC Educational Resources Information Center

Purpose: The primary purpose of this study was to measure the 16-year change in peak compensated static acoustic admittance (Peak Y[subscript tm]) in a population-based cohort of older adults, and to determine whether age was associated with any observed change in Peak Y[subscript tm]. Other tympanometric measures also were taken and analyzed.…

Nondahl, David M.; Cruickshanks, Karen J.; Wiley, Terry L.; Tweed, Ted S.; Dalton, Dayna S.

2013-01-01

95

Characterization of coding domains by optimally implementing optimal trade-off (OT) filters in the joint transform correlator  

Microsoft Academic Search

We propose to characterize various coding domains for the joint transform correlator. To achieve that, optimal trade- off filters have ben computed and then optimally constrained to given coding domains with an algorithm we have developed. Then, these coding domains have been evaluated in relation to the trade-offs they achieve.

Laurent Bigue; Michel Fraces; Pierre Ambs

1996-01-01

96

Computerized characterization of masses on mammograms: the rubber band straightening transform and texture analysis.  

PubMed

A new rubber band straightening transform (RBST) is introduced for characterization of mammographic masses as malignant or benign. The RBST transforms a band of pixels surrounding a segmented mass onto the Cartesian plane (the RBST image). The border of a mammographic mass appears approximately as a horizontal line, and possible speculations resemble vertical lines in the RBST image. In this study, the effectiveness of a set of directional textures extracted from the images before the RBST. A database of 168 mammograms containing biopsy-proven malignant and benign breast masses was digitized at a pixel size of 100 microns x 100 microns. Regions of interest (ROIs) containing the biopsied mass were extracted from each mammogram by an experienced radiologist. A clustering algorithm was employed for automated segmentation of each ROI into a mass object and background tissue. Texture features extracted from spatial gray-level dependence matrices and run-length statistics matrices were evaluated for three different regions and representations: (i) the entire ROI; (ii) a band of pixels surrounding the segmented mass object in the ROI; and (iii) the RBST image. Linear discriminant analysis was used for classification, and receiver operating characteristic (ROC) analysis was used to evaluate the classification accuracy. Using the ROC curves as the performance measure, features extracted from the RBST images were found to be significantly more effective than those extracted from the original images. Features extracted from the RBST images yielded an area (Az) of 0.94 under the ROC curve for classification of mammographic masses as malignant and benign. PMID:9571620

Sahiner, B; Chan, H P; Petrick, N; Helvie, M A; Goodsitt, M M

1998-04-01

97

Admittance Survey of Type 1 Coronae on Venus: Implications for Elastic Thickness  

NASA Technical Reports Server (NTRS)

Coronae are volcano-tectonic features on Venus which range from 60km to 2600km and are defined by their nearly circular patterns of fractures. Type 1 (regular) coronae are classified as having >50% complete fracture annuli. Previous work has examined the factors controlling the morphology, size, and fracture pattern of coronae, using lithospheric properties, loading signature and geologic characteristics. However, these studies have been limited to Type 2 (topographic) coronae (e.g. coronaes with <50% fracture annuli), and the factors controlling the formation of Type 1 coronae remain poorly understood. In this study, we apply the methodology of to survey the admittance signature for Type 1 coronae to determine the controlling parameters which govern Type 1 coronae formation.

Hoogenboom, T.; Smrekar, S. E.; Anderson, F. S.; Houseman, G.

2003-01-01

98

Determination of electron mobility in tris(8-hydroxy-quinolinato) aluminum by admittance spectroscopy  

NASA Astrophysics Data System (ADS)

The electron mobilities of tris(8-hydroxy-quinolinato) aluminum (Alq3) thin films at various thicknesses (70-280 nm) have been determined by using admittance spectroscopy measurements. Our results show that the electric field dependence of electron mobilities exhibits different behaviors at different thicknesses of Alq3 films. Clearly, when the thickness of Alq3 film is less than 150 nm, the electron mobilities slightly decrease with increasing the electric field. For the thickness of Alq3 film more than 150 nm, however, the mobilities increase as the electric field increases. The phenomena are well discussed by energetic disorder. Using temperature dependent I-V characteristics, we further calculated the density of traps.

Wang, Yanping; Chen, Jiangshan; Dong, Lisong; Ma, Dongge

2013-09-01

99

Characterization of the Si:H network during transformation from amorphous to micro- and nanocrystalline structures  

NASA Astrophysics Data System (ADS)

Optical, structural, and electrical characterizations of the Si:H network have been performed during its changes occurred by the increasing H2 dilution to the SiH4 ensemble in hot-wire chemical vapor deposition (HWCVD). A rapid structural transformation from a mostly amorphous phase to comprehensive micro/nanocrystallinity was attained at a relatively low H2 dilution, even at a low substrate temperature, because of the associated abundance of atomic H in HWCVD. However, elevated H2 dilution induces enormous polyhydrogenation and formation of lesser dense network full of voids, mostly around the tiny micro/nanocrystallites. This highly defective grain boundary zone provides high density of electronic trapping centers and contributes significantly to the transport of carriers. The overall electrical transport in the amorphous-micro-nano-crystalline heterogeneous Si:H network has been accounted in the framework of a three-phase model comprised of amorphous and crystalline (micro- and nano-) components while the grain boundary being the third phase, separately contributing to a potential energy barrier in between. The three-phase model to the electrical phenomena of nanocrystalline structures convincingly explains the dual activation energies arising in the electrical conduction with distinguishably different temperature dependent behaviors from that occurs in the conventional amorphous matrix.

Das, Debajyoti; Bhattacharya, Koyel

2006-11-01

100

Characterization of primary human keratinocytes transformed by human papillomavirus type 18  

SciTech Connect

Primary human epithelial cells were cotransfected with pHPV-18 and pSV2neo, and cell strains were generated by selecting in G418. Southern blot analysis revealed the presence of at least one intact, integrated viral genome in these cells. FE-A cells showed altered growth properties, characterized by a change in morphology, and clonal density. Differentiation markers analyzed by Western blotting (immunoblotting), such as cytokeratins and involucrin, indicated that the cells resembled a partially differentiated epithelial population. Increased expression of the 40-kilodalton cytokeratin was observed in FE-A cells, similar to that observed in simian virus 40-immortalized human keratinocytes. Calcium and 12-O-tetradecanoyl-phorbol-13-acetate treatment induced normal epithelial cells to differentiate, whereas the human papillomavirus 18 (HPV-18)-containing keratinocytes were resistant to these signals, indicating their partially transformed nature. These cells were not able to induce tumors in nude mice over a period of up to 8 months. A second cell strain, FE-H18L, also generated by transfecting HPV-18, also exhibited an extended life span and similar alterations in morphology. Viral RNA transcribed from the early region of HPV-18 was detected in both cell strains by Northern (RNA) blot analysis. These cell strains should provide a useful model for determining the role of HPV in carcinogenesis.

Kaur, P.; McDougall, J.K. (Fred Hutchinson Cancer Research Center, Seattle, WA (USA))

1988-06-01

101

Laval nozzle flow characterization by Fourier-transform Mach-Zehnder interferometry  

NASA Astrophysics Data System (ADS)

The role of the assist gas blown by a nozzle during the laser cutting process of ceramics is very important as a complex flow field is created by the interaction with the material. Flow visualization provides valuable information related with the properties and characteristics of the process in order to clear up misconceptions and as a first step towards the nozzle optimization. Optical methods as Schlieren or interferometry are suitable techniques for this task as well-known non-intrusive full-field methods utilized for analysing fast transient flow phenomena. In this work a Mach-Zehnder interferometer is employed in order to characterize a Laval nozzle by studying the shock wave patterns in a free gas jet as a previous step in order to study the complex interaction of the gas flow against a transparent model of the processed material. The optical phase is extracted from the obtained high-frequency fringe pattern by the Fourier Transform Phase-Difference Method. Disturbing effects are cancelled by proper combination of high-frequency fringe patterns obtained with and without gas flow. The shock wave pattern is analyzed for different geometrical configurations and operating pressures.

Rodriguez, Francisco; Dorrio, Benito V.; Doval, Angel F.; Trillo, Cristina; Quintero, Felix; Miranda, Marta; Lopez, Carlos; Fernandez, Jose L.

2005-06-01

102

Quantitative characterization of the surface topography of rolled sheets by laser scanning microscopy and fourier transformation  

NASA Astrophysics Data System (ADS)

The surface of twin-roll cast aluminum sheets undergoes dramatic changes during cold rolling. This is mainly due to variables in the roll gap, topography of the rolls, lubrication, material properties, and in particular the initial structure and topography of the cast sheet. Therefore, it is important to have means to quantitatively describe the changes in the surface structure of each pass and from pass to pass in order to optimize the desired final surface structure. To achieve this, the laser scanning microscope (LSM) with its confocal technique has been employed to image the three-dimensional (3-D) topography and to digitize the image for further computer analysis. The digitization of the image is primarily motivated by the need to introduce a Fourier transformation of the surface topography. The method is effective in describing qualitative periodic trends in the surface features. Information is gained on the shape and periodicities as well as roughness directionality. For instance, grooves and cross hatches and their remnants can be followed from one pass to the other. Important characteristics of the surface topography such as rolling ridges and shingles can also easily be characterized.

Gjønnes, Liv

1996-08-01

103

Rapid recovery- and characterization of transformants following Agrobacterium -mediated T-DNA transfer to sorghum  

Microsoft Academic Search

Although Agrobacterium-mediated transformation of sorghum has been reported, the process is rather lengthy and remains difficult, requiring some\\u000a very stringent conditions to obtain transformants. We have investigated and describe the parameters related to cocultivation,\\u000a culture, and regeneration that have allowed us to obtain transgenic sorghum plants in as little as 2.5 months. We observed\\u000a a 2.9-fold increase in transformation efficiency when

Vinod Kumar; LeAnne M. Campbell; Keerti S. Rathore

2011-01-01

104

Characterization of Transformation Stasis in Low-Carbon Steels Microalloyed with B and Mo  

NASA Astrophysics Data System (ADS)

In the present study, bainite transformation kinetics was examined in low C-Mn steels with the addition of small amounts of B and Mo. This addition delays the onset of the bainite transformation. Mo addition causes transformation stasis at temperatures between 873 K and 823 K (600 °C and 550 °C) just below the bainite-start ( B s) temperature, resulting from an incomplete bainite transformation. Post-stasis transformation after a prolonged hold proceeds by the formation of ferrite with a low dislocation density, and in Mo-containing alloys, often the formation of carbides. The volume fraction at which the transformation stops is higher for lower carbon contents and lower transformation temperatures. By contrast, at 773 K (500 °C), the bainite transformation accompanying cementite precipitation occurs regardless of microalloying and is completed after shorter hold times. EDX measurement performed on the Mo-added 0.15 pct C alloy with aberration-corrected STEM revealed that segregation at the bainite/austenite interphase boundary is small for Mn and negligible for Mo in the early stages of stasis, which does not support the incomplete transformation mechanism based on the solute drag theory for the alloys used.

Furuhara, Tadashi; Tsuzumi, Kenji; Miyamoto, Goro; Amino, Takafumi; Shigesato, Genichi

2014-12-01

105

Characterization of masses on mammograms: significance of using the rubber band straightening transform  

NASA Astrophysics Data System (ADS)

The rubber-band straightening transform (RBST) was developed for characterization of mammographic masses as malignant or benign. The RBST maps a region surrounding a segmented mass on a mammogram onto the Cartesian plane. In this study, the effectiveness of texture features extracted from the RBST images was compared with the effectiveness of those extracted from the original images. Texture features were extracted from (1) a region of interest (ROI) centered at the mass; (2) a 40-pixel-wide gray-scale region surrounding the perimeter of the mass; and (3) the RBST image. Two types of texture features were extracted; spatial gray level dependence (SGLD) features and run-length statistics (RLS) features. Linear discriminant analysis and leave-one-case- out methods were used for classification in the individual or combined feature spaces. The classification accuracy was evaluated by receiver operating characteristic (ROC) analysis and the area Az under the ROC curve. CLABROC analysis was used to estimate the statistical significance of the difference between features extracted using the three different approaches. On a database of 255 ROIs containing biopsy-proven masses, the Az value was 0.92 when combined SGLD and RLS features extracted from RBST images were used for classification. In comparison, the combined texture features extracted from the entire ROIs and the mass perimeter regions resulted in Az values of 0.83 and 0.85, respectively. The improvement in Az obtained by using RBST images was statistically significant (p less than 0.05). Similar levels of significance were observed when the classification was performed in the SGLD feature space alone or the RLS feature space alone.

Sahiner, Berkman; Chan, Heang-Ping; Petrick, Nicholas; Goodsitt, Mitchell M.; Helvie, Mark A.

1997-04-01

106

Characterization of directly transformed weedy Brassica rapa and introgressed B. rapa with Bt cry1Ac and gfp genes  

Microsoft Academic Search

Crop to weed transgene flow, which could result in more competitive weed populations, is an agricultural biosafety concern.\\u000a Crop Brassica napus to weedy Brassica rapa hybridization has been extensively characterized to better understand the transgene flow and its consequences. In this study,\\u000a weedy accessions of B. rapa were transformed with Bacillus thuringiensis (Bt) cry1Ac- and green fluorescence protein (gfp)-coding transgenes

Hong S. Moon; Matthew D. Halfhill; Laura L. Good; Paul L. Raymer; C. Neal Stewart

2007-01-01

107

High density trans-admittance mammography development and preliminary phantom tests  

PubMed Central

Background Malignant breast tumor tissue has a significantly different electrical impedance spectrum than surrounding normal tissues. This has led to the development of impedance imaging as a supplementary or alternative method to X-ray mammography for screening and assessment of breast cancers. However low spatial resolution and poor signal to noise ratio has limited the clinical application. Methods In order to improve spatial resolution we developed a trans-admittance mammography (TAM) system including an array of 60×60 current sensing electrodes. We adopted a similar setup to X-ray mammography where the breast is situated between two holding plates. The top plate is a large solid metal electrode for applying a sinusoidal voltage over a range of frequencies from 50 Hz to 500 kHz. The bottom plate has 3600 current sensing electrodes that are kept at the ground potential. Currents are generated from the top voltage-applying electrode and spread throughout the breast, entering the TAM system through the array of current sensing electrodes on the bottom plate. The TAM system measures the exit currents through 6 switching modules connected to 600 electrodes each. Each switching module is connected to 12 ammeter channels which are switched sequentially to 50 of the 600 electrodes each measurement time. Each ammeter channel is comprised of a current-to-voltage converter, a gain amplifier, filters, an analog to digital converter, and a digital phase sensitive demodulator. Results We found an average noise level of 38 nA, amplitude stability of less than 0.2%, crosstalk of better than -60 dB and 70 dB signal to noise ratio over all channels and operating frequencies. Images were obtained in time difference and frequency difference modes in a saline phantom. Conclusion We describe the design, construction, and calibration of a high density TAM system in detail. Successful high resolution time and frequency difference images showed regions of interest with the expected admittivity changes in the frequency spectrum. PMID:23009288

2012-01-01

108

Dielectric characterization of power transformer oils as a diagnostic life prediction method  

Microsoft Academic Search

The monitoring of the complex permittivity of transformer oils as a function of frequency and temperature provides information concerning the state of the insulation. In this work, it has been investigated as a quality control method, providing service life estimations of power transformations. The formation of databases recording polarization effects in a wide frequency and temperature range may be used

C. T. Dervos; C. D. Paraskevas; P. Skafidas; P. Vassiliou

2005-01-01

109

Characterization of Si-based monolithic transformers with patterned ground shield  

Microsoft Academic Search

This paper investigates the impact of patterned ground shield on monolithic integrated transformers. The minimum insertion loss is shown to be a useful figure of merit. It is used to evaluate transformer performances. We demonstrate that the use of a patterned ground shield increases the quality factor of both primary and secondary coils. It increases also the mutual coupling coefficient

Ouail El-Gharniti; Eric Kerhervé; Jean-Baptiste Bégueret

2006-01-01

110

Acoustic gravity waves during solar eclipses: Detection and characterization using wavelet transforms  

Microsoft Academic Search

In the present contribution, we first propose a methodology that enables to detect wave-like structures propagating in ionosphere, by tracking the local maxima of the modulus of continuous complex wavelet transform coefficients with respect to heights. From the derivation of the phases of the wavelet transform, we measure the corresponding propagation parameters. These tools are applied to measurements collected by

P. Sauli; S. G. Roux; P. Abry; J. Boska

2007-01-01

111

Acoustic–gravity waves during solar eclipses: Detection and characterization using wavelet transforms  

Microsoft Academic Search

In the present contribution, we first propose a methodology that enables to detect wave-like structures propagating in ionosphere, by tracking the local maxima of the modulus of continuous complex wavelet transform coefficients with respect to heights. From the derivation of the phases of the wavelet transform, we measure the corresponding propagation parameters. These tools are applied to measurements collected by

P. Šauli; S. G. Roux; P. Abry; J. Boška

2007-01-01

112

An Admittance Survey of Large Volcanoes on Venus: Implications for Volcano Growth  

NASA Technical Reports Server (NTRS)

Estimates of the thickness of the venusian crust and elastic lithosphere are important in determining the rheological and thermal properties of Venus. These estimates offer insights into what conditions are needed for certain features, such as large volcanoes and coronae, to form. Lithospheric properties for much of the large volcano population on Venus are not well known. Previous studies of elastic thickness (Te) have concentrated on individual or small groups of edifices, or have used volcano models and fixed values of Te to match with observations of volcano morphologies. In addition, previous studies use different methods to estimate lithospheric parameters meaning it is difficult to compare their results. Following recent global studies of the admittance signatures exhibited by the venusian corona population, we performed a similar survey into large volcanoes in an effort to determine the range of lithospheric parameters shown by these features. This survey of the entire large volcano population used the same method throughout so that all estimates could be directly compared. By analysing a large number of edifices and comparing our results to observations of their morphology and models of volcano formation, we can help determine the controlling parameters that govern volcano growth on Venus.

Brian, A. W.; Smrekar, S. E.; Stofan, E. R.

2004-01-01

113

Admittance spectroscopy and electrical properties of Co3O4-doped ZnO  

NASA Astrophysics Data System (ADS)

The varistor characteristics of 0.1-3.0 at. % Co-doped ZnO have been investigated. Three kinds of deep bulk trap levels of 0.16, 0.25, and ~0.31 eV were identified as donor levels by admittance spectroscopy. Oxygen vacancy ( V o ·) appeared preferentially in 0.5-3.0 at. % Co-doped ZnO. From J-E characteristics nonohmic behavior was seen in this binary system while the nonlinear coefficient ? changed between 3 and 35 depending on the composition. For 1.0 at. % Co-doped ZnO, two distinguishable activation energies of 0.65 eV and 1.04 eV related with grain boundary phenomena were confirmed above and below ~520 K by impedance and modulus spectroscopy. It is believed that the varistor behavior of Co-doped ZnO stems from the formation of double Schottky barrier by the valence change of Co ions in ZnO grains as well as oxygen chemisorption at the grain boundaries on heating and subsequent cooling.

Hong, Youn-Woo; Lee, Young-Jin; Kim, Sei-Ki; Paik, Jong-Hoo; Kim, Jin-Ho

2014-09-01

114

Impedance and admittance matrices of symmetric piezoelectric annular bimorphs and their applications  

PubMed

The 5 x 5 impedance and admittance matrices of a symmetric triple-layer piezoelectric annular bimorph (PAB) are presented and the PAB with the piezoelectric layers partially covering the shim layer in harmonic motion is analyzed using the matrices. The electromechanical flow vectors are defined as the mechanical displacements and rotations at the inner and outer boundaries and the electric current of the piezoelectric layer; the conjugate parameters, i.e., the electromechanical effort vectors, are accordingly defined. The impedance matrix which relates the flow vector with the effort vector is divided into three matrices, the mechanical, electrical, and electromechanical coupling impedance matrices; each matrix is represented by a block network with five ports. The resonance and the antiresonance frequencies and the effective electromechanical coupling factors of the PAB excited by the partially covering piezoelectric layers are then calculated for various boundary conditions imposed at the inner and outer surfaces. The numerical results by the impedance matrix are compared with those by the finite element methods; they are in excellent agreement with each other. It is also shown that the matrix representations can be easily applied to the piezoelectric circular bimorph (PCB) with the extended shim layer. PMID:11108350

Ha; Kim

2000-11-01

115

Fabrication and characterization of a switchable flux transformer using a DC-SQUID  

NASA Astrophysics Data System (ADS)

We have investigated a switchable flux transformer which consists of a superconducting loop and a DC-SQUID. The effective magnetic flux in the DC-SQUID was controlled by a control current, which was injected in the segment of the SQUID loop. The equation describing the behavior of the circulating current in the transformer was derived. We fabricated the flux transformer coupled with an input coil and a readout DC-SQUID. The characteristics of the flux transformer were measured in a dilution refrigerator. The results demonstrate that the flux transfer function can be strongly modulated by the control current. This device could be applied to realize controllable coupling between flux qubits for efficient operation on multiple qubits.

Shimazu, Y.; Niizeki, T.; Wada, Y.

2006-10-01

116

Transformation and Characterization of Transgenic Plants of Solanum dulcamara L.—Incidence of Transgene Silencing  

Microsoft Academic Search

A transformation system is described for Solanum dulcamara using the supervirulentAgrobacterium tumefaciens strain 1065, carrying both the ?-glucuronidase (gus) and neomycin phosphotransferase II (npt II) genes adjacent to the right and left T-DNA borders, respectively. Leaf explants were more efficient for the production of transformed plants compared to stem explants on medium containing 50mgl?1of kanamycin sulphate. A 1:10 (v:v) dilution

I. S. Curtis; J. B. Power; P. Hedden; A. Phillips; K. C. Lowe; D. A. Ward; M. R. Davey

2000-01-01

117

Characterization of the transformation from calcium-deficient apatite to ?-tricalcium phosphate  

Microsoft Academic Search

The structural changes that occur during the transformation of a Ca-deficient apatite, prepared by a wet chemical method, to ß-TCP were investigated. X-ray diffraction (XRD) analysis of as-prepared samples and samples calcined at temperatures between 500 and 1100 °C showed that the transformation occurs over the temperature range 710–740 °C, under non-equilibrium conditions. The change in crystallite size with increasing

I. R. Gibson; I. Rehman; S. M. Best

2000-01-01

118

Characterization of fossil organic matter with Fourier-Transform Infrared (FTIR) Spectroscopy: an attempt to record extraterrestrial life .  

NASA Astrophysics Data System (ADS)

The characterization of the insoluble macromolecular fraction of organic matter preserved in carbonate sediments allows the identification of fossil organisms otherwise not recognizable. This approach represents a new tool for the detection of extraterrestrial traces of life even in their primitive form, one of the primary goals of exobiological studies on Mars. Considering the deep connection between carbonate sediments and biological activities on Earth, we checked if it was possible to characterize the organic matter remains dispersed within these rocks, with Fourier transform infrared (FTIR) spectroscopy. The experiment was performed on ancient and well preserved carbonates, belonging to the Calcare di Base Formation outcropping in Northern Calabria (Rossano Basin). The origin of these Miocene deposits is problematic, due to the absence of skeletal fossils. The results demonstrate that FTIR is a reliable method for the characterization of the organic matter preserved in carbonates, and generally in all types of sedimentary rocks.

Guido, A.; Mastandrea, A.; Tosti, F.; Demasi, F.; Blanco, A.; D'Elia, M.; Orofino, V.; Fonti, S.; Russo, F.

119

Characterizing photochemical transformation of aqueous nC60 under environmentally relevant conditions.  

PubMed

Engineered nanomaterials may undergo transformation upon interactions with various environmental factors. In this study, photochemical transformation of aqueous nC60 was investigated under UVA irradiation. nC60 underwent photochemical transformation in the presence of dissolved O2, resulting in surface oxygenation and hydroxylation as demonstrated by XPS and ATR-FTIR analyses. The reaction followed a pseudo-first order rate law with the apparent reaction rate constant of 2.2 x 10(-2) h(-1). However, the core of the nanoparticles remained intact over 21 days of irradiation. Although no mineralization or dissolution of nC60 was observed, experiments using fullerol as a reference fullerene derivative suggested likely dissolution and partial mineralization of nC60 under long-term UVA exposure. Aquatic humic acid reduced nC60 transformation kinetics presumably due to scavenging of reactive oxygen species. Results from this study imply that photochemical transformation is an important factor controlling nC60 physical and chemical properties as well as its fate and transport in the natural aqueous environment. In addition, changes in nC60 surface chemistry drastically reduced C60 extraction efficiency by toluene, suggesting that the existing analytical method for C60 may not be applicable to environmental samples. PMID:20337472

Hwang, Yu Sik; Li, Qilin

2010-04-15

120

Characterization of pyrogenic black carbon by desorption atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry.  

PubMed

We present a new method for molecular characterization of intact biochar directly, without sample preparation or pretreatment, on the basis of desorption atmospheric pressure photoionization (DAPPI) coupled to Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. Conventional ionization methods (e.g., electrospray or atmospheric pressure photoionization) for characterization of natural organic matter have limited utility for the characterization of chars due to incomplete solubility in common solvents. Therefore, direct ionization techniques that do not require sample dissolution prior to analysis are ideal. Here, we apply DAPPI FTICR mass spectrometry to enable the first molecular characterization of uncharred parent oak biomass and after combustion (250 °C) or pyrolysis (400 °C). Parent oak is primarily composed of cellulose-, lignin-, and resin-like compounds. Oak combusted at 250 °C contains condensed aromatic compounds with low H/C and O/C ratios while retaining compounds with high H/C and O/C ratios. The bimodal distribution of aromatic and aliphatic compounds observed in the combusted oak sample is attributed to incomplete thermal degradation of lignin and hemicellulose. Pyrolyzed oak constituents exhibit lower H/C and O/C ratios: approximately three-quarters of the identified species are aromatic. DAPPI FTICR MS results agree with bulk elemental composition as well as functional group distributions determined by elemental analysis and solid state (13)C NMR spectroscopy. Complete molecular characterization of biomass upon thermal transformation may provide insight into the biogeochemical cycles of biochar and future renewable energy sources, particularly for samples currently limited by solubility, separation, and sample preparation. PMID:22242739

Podgorski, David C; Hamdan, Rasha; McKenna, Amy M; Nyadong, Leonard; Rodgers, Ryan P; Marshall, Alan G; Cooper, William T

2012-02-01

121

An analysis of light-induced admittance changes in rod outer segments  

PubMed Central

1. Measurements were made of the time course and amplitude of the change in real part of admittance, ?G, of a suspension of frog rod outer segments, following a flash of light bleaching about 1% of the rhodopsin content of the rods. The measurements, based on the use of a specially designed marginal oscillator, covered the frequency range between 500 Hz and 17 MHz. 2. The components of response, previously described for rods prepared by a method involving exposure to strongly hypertonic sucrose solutions, are present in similar form when rods are isolated and maintained in isotonic solutions made up with equi-osmotic concentrations of NaCl and sucrose or with Na2SO4. 3. Component I, identified as a slowly developing positive ?G apparent at very low frequencies, is frequency-independent up to the characteristic frequency of admittance for the suspension, fY (about 2 MHz for rods suspended in a solution having the conductivity of Ringer solution), but decreases at still higher frequencies. 4. Component II, identified as a rapidly developing positive ?G which appears only above a critical frequency about 2·5 decades below fY, increases approximately logarithmically with frequency to reach a limiting amplitude in the region of fY. 5. The amplitude of component II, ?GII, measured in the region of fY, varies linearly with the conductivity of the suspending medium, Go, under conditions in which the conductivity of the rod interior is also a linear function of the external conductivity. The relation for a flash bleaching 1% of the rhodopsin content of the dark-adapted rod is [Formula: see text] 6. Measurements made on rods suspended in a low-conductivity solution, which has the effect of reducing the conductivity of the rod interior to about one ninth its value for rods suspended in Ringer solution, reveal a decline in component II for frequencies above 8 MHz. 7. To explain the frequency dependence of component II and its dependence on conductivity, it is proposed that component II arises from a light-induced increase in conductance of the disk membranes which obstruct the longitudinal flow of current through the rod interior except at very high frequencies. 8. The disk-membrane conductance increase for rods suspended in a solution having the conductivity of Ringer solution is calculated to be 4·3 × 10-11 mho/rhodpsin molecule bleached, a value which is similar to what has been found for ionic channels operated by membrane potential change in the nerve membrane and by synaptic transmitter in the postjunctional membrane. 9. No component of response has been observed which could be reliably attributed to a surface membrane conductance decrease of the type observed in receptor cells in the retina. PMID:4540195

Falk, G.; Fatt, P.

1973-01-01

122

Characterization of biomass burning: Fourier transform infrared analysis of wood and vegetation combustion products  

Microsoft Academic Search

The Fourier transform infrared examination of the combustion products of a selection of forest materials has been undertaken in order to guide future detection of biomass burning using satellite remote sensing. Combustion of conifer Pinus strobus (white pine) and deciduous Prunus serotina (cherry), Acer rubrum (red maple), Friglans nigra (walnut), Fraxinus americana (ash), Betula papyrifera (birch), Querus alba (white oak)

Diomaris Padilla

2008-01-01

123

Characterization of knocking combustion in HCCI DME engine using wavelet packet transform  

Microsoft Academic Search

A diesel engine is modified for homogeneous charge compression ignition (HCCI) combustion with dimethyl ether. With and without knock, in-cylinder pressure is acquired, and in-cylinder temperature, rate of heat release (ROHR), pressure rise rate and pressure rise acceleration obtained. Wavelet packet transform is performed to decompose pressure signal into three layers with subsignals obtained. Three wavelet packet quantifiers for seven

Junxing Hou; Xinqi Qiao; Zhen Wang; Wei Liu; Zhen Huang

2010-01-01

124

Lime kiln source characterization: Lime manufacturing industry Fourier transform infrared spectroscopy. Final report  

SciTech Connect

The purpose of this testing program is to obtain uncontrolled and controlled hydrogen chloride (HCl) and speciated hydrocarbon Hazardous Air Pollutants (HAPs) emissions data from lime production plants to support a national emission standard for hazardous air pollutants (NESHAP). This report presents data from the Fourier Transform Infrared Spectroscopy (FTIR) measurements. FTIR source testing was conducted for the following purposes: Quantify HCl emission levels; and Gather screening (i.e., qualitative) data on other HAP emissions.

Toney, M.L.

1999-07-01

125

Transformation of chloroplast ribosomal RNA genes in Chlamydomonas: molecular and genetic characterization of integration events.  

PubMed

Transformation of chloroplast ribosomal RNA (rRNA) genes in Chlamydomonas has been achieved by the biolistic process using cloned chloroplast DNA fragments carrying mutations that confer antibiotic resistance. The sites of exchange employed during the integration of the donor DNA into the recipient genome have been localized using a combination of antibiotic resistance mutations in the 16S and 23S rRNA genes and restriction fragment length polymorphisms that flank these genes. Complete or nearly complete replacement of a region of the chloroplast genome in the recipient cell by the corresponding sequence from the donor plasmid was the most common integration event. Exchange events between the homologous donor and recipient sequences occurred preferentially near the vector:insert junctions. Insertion of the donor rRNA genes and flanking sequences into one inverted repeat of the recipient genome was followed by intramolecular copy correction so that both copies of the inverted repeat acquired identical sequences. Increased frequencies of rRNA gene transformants were achieved by reducing the copy number of the chloroplast genome in the recipient cells and by decreasing the heterology between donor and recipient DNA sequences flanking the selectable markers. In addition to producing bona fide chloroplast rRNA transformants, the biolistic process induced mutants resistant to low levels of streptomycin, typical of nuclear mutations in Chlamydomonas. PMID:1981764

Newman, S M; Boynton, J E; Gillham, N W; Randolph-Anderson, B L; Johnson, A M; Harris, E H

1990-12-01

126

Isolation and characterization of four adenovirus type 12-transformed human embryo kidney cell lines.  

PubMed Central

Four transformed cell lines were established from cultures of human embryo kidney (HEK) cells microinjected or transfected with cloned adenovirus 12 (Ad12) EcoRI-C DNA (0 through 16.5 map units of the left-hand end of the viral genome). Each cell line showed a different growth pattern. Southern blotting demonstrated that all of the cell lines contained Ad12-specific DNA sequences, but in the microinjected isolates these were at a much lower copy number than in the transfected isolate. Two cell lines (Ad12 HEK 1 and 3) appeared to contain tandemly repeated Ad12 EcoRI-C DNA fragments. Immunoprecipitation and Western blotting confirmed that Ad12 early region 1 (E1) proteins were being expressed by all four of the transformed cell lines, but indicated that E1A polypeptide expression was considerably less than E1B polypeptide expression. All of the Ad12-transformed HEK cell lines were tumorigenic when inoculated intracranially into athymic nude mice. Images PMID:6700581

Whittaker, J L; Byrd, P J; Grand, R J; Gallimore, P H

1984-01-01

127

Characterization of tumors produced by signal peptide-basic fibroblast growth factor-transformed cells.  

PubMed

Basic fibroblast growth factor (bFGF) is found in a variety of cells and tissues. We have previously shown that bFGF is a transforming growth factor, but only when fused to a signal peptide (sp-bFGF). Cells expressing the native bFGF are tumorigenic in nude mice only, where the tumors form at a low frequency and grow very slowly as compared to sp-bFGF tumors. The cells transformed by the sp-bFGF growth factor gene cause rapidly growing tumors within 10 days in 100% of syngeneic and nude mice. In nude mice, the tumors are highly vascularized, while the vascularization in immunocompetent syngeneic mice is not as prominent. The syngeneic mice have a characteristic humoral immune response to sp-bFGF tumors, which differs from that mounted against ras-induced tumors. The ability of bFGF to induce tumorigenicity is significant in view of the recent discoveries of three new oncogenes: hst, int-2, and an oncogene from a human colon cancer. In addition to homology with FGF, the proteins encoded by these oncogenes all have a potential signal peptide at the protein's amino terminus, suggesting a mode of action analogous to that of our artificial signal peptide-bFGF (sp-bFGF) transforming growth factor model system. PMID:2469690

Rogelj, S; Weinberg, R A; Fanning, P; Klagsbrun, M

1989-01-01

128

Processing and characterization of transformation-toughened ceramics with strength retention to elevated temperatures. Final report  

SciTech Connect

Monolithic and three-layered Al{sub 2}O{sub 3} -- 15 vol % ZrO{sub 2} composites were fabricated by slip casting aqueous slurries. The outer and inner layers of three-layer composites contained unstabilized and partially stabilized ZrO{sub 2}, respectively. Transformation of part of the unstabilized ZrO{sub 2} led to surface compressive stresses in the outer layers. Strain gage, x-ray, indentation crack length, and strength measurements were used to determine the magnitude of residual stresses in the composites. The strength of the three-layer composites ({approx}1200 MPa) was 500--700 MPa higher than that of the monolithic outer layer composites at room temperature and 350 MPa higher at 750{degree}C. The strength differential decreased rapidly above the m {yields} t transformation temperature. Three-layered composites showed excellent damage resistance and improved reliability. Cam follower rollers were fabricated to demonstrate the applicability of this technique for making automotive components.

Cutler, R.A.; Brinkpeter, C.B. [Ceramatec, Inc., Salt Lake City, UT (United States); Vircar, A.V.; Shetty, D.K. [Univ. of Utah (United States)

1994-09-01

129

Monoclonal antibodies as developmental markers to characterize pea floral homeotic transformations  

Microsoft Academic Search

Monoclonal antibodies (mAbs) specific for the different floral organs of the garden pea ( Pisum sativum L.) were raised using two different types of immunization procedures. These antibodies were powerful tools to study the functionality of floral organ identity genes in pea homeotic mutants. The mAbs were used extensively as developmental markers for the immunohistochemical characterization of two pea floral

Luis A. Cañas; Roudeïna Essid; María D. Gómez; José Beltrán

2002-01-01

130

Using Texture Descriptor and Radon Transform to Characterize Protein Structure and Build Fast Fold Recognition  

Microsoft Academic Search

One of the most important research aims is to understand the relationship between structure and function of protein. Inspired by this motivation, automatic classification of protein structure becomes one of major research approaches. However, how to extract compact and effective feature to characterize protein structure is still a challenge to it. In this paper, 3-D tertiary structure of protein fold

Jian-Yu Shi; Yan-Ning Zhang

2009-01-01

131

Force Control and Nonlinear Master-Slave Force Profile to Manage an Admittance Type Multi-Fingered Haptic User Interface  

SciTech Connect

Natural movements and force feedback are important elements in using teleoperated equipment if complex and speedy manipulation tasks are to be accomplished in remote and/or hazardous environments, such as hot cells, glove boxes, decommissioning, explosives disarmament, and space to name a few. In order to achieve this end the research presented in this paper has developed an admittance type exoskeleton like multi-fingered haptic hand user interface that secures the user’s palm and provides 3-dimensional force feedback to the user’s fingertips. Atypical to conventional haptic hand user interfaces that limit themselves to integrating the human hand’s characteristics just into the system’s mechanical design this system also perpetuates that inspiration into the designed user interface’s controller. This is achieved by manifesting the property differences of manipulation and grasping activities as they pertain to the human hand into a nonlinear master-slave force relationship. The results presented in this paper show that the admittance-type system has sufficient bandwidth that it appears nearly transparent to the user when the user is in free motion and when the system is subjected to a manipulation task, increased performance is achieved using the nonlinear force relationship compared to the traditional linear scaling techniques implemented in the vast majority of systems.

Anthony L. Crawford

2012-08-01

132

Characterization and Modeling of Transformation Induced Fatigue of Shape Memory Alloy Actuators  

E-print Network

Members, James G. Boyd Vikram K. Kinra Ibrahim Karaman Gary T. Fry Etienne Patoor Head of Department, Dimitris C. Lagoudas December 2009 Major Subject: Aerospace Engineering iii ABSTRACT Characterization and Modeling... sincere appreciation to my undergraduate advisor, PhD mentor, and co-advisor, Dr. Etienne Patoor, whom I met when I was working at the Ecole Nationale Sup?rieure D?Arts et M?tiers in Metz, France. He maintained a never ending trust and confidence...

Bertacchini, Olivier Walter

2011-02-22

133

Characterization of near-terahertz complementary metal-oxide semiconductor circuits using a Fourier-transform interferometer  

DOE PAGESBeta

Optical methods for measuring of the emission spectra of oscillator circuits operating in the 400–600 GHz range are described. The emitted power from patch antennas included in the circuits is measured by placing the circuit in the source chamber of a Fourier-transform interferometric spectrometer. The results show that this optical technique is useful for measuring circuits pushing the frontier in operating frequency. The technique also allows the characterization of the circuit by measuring the power radiated in the fundamental and in the harmonics. This capability is useful for oscillator architectures designed to cancel the fundamental and use higher harmonics. The radiated power was measured using two techniques: direct measurement of the power by placing the device in front of a bolometer of known responsivity, and by comparison to the estimated power from blackbody sources. The latter technique showed that these circuits have higher emission than blackbody sources at the operating frequencies, and, therefore, offer potential spectroscopy applications.

Arenas, D. J. [Univ. of North Florida, Jacksonville, FL (United States); Shim, Dongha [Univ. of Florida, Gainesville, FL (United States); Koukis, D. I. [Univ. of Florida, Gainesville, FL (United States); Seok, Eunyoung [Univ. of Florida, Gainesville, FL and Texas Instruments, Dallas, TX (United States); Tanner, D. B. [Univ. of Florida, Gainesville, FL (United States); O, Kenneth K. [Univ. of Texas, Dallas, TX (United States)

2011-10-24

134

Synthesis of lead zirconate titanate nanofibres and the Fourier-transform infrared characterization of their metallo-organic decomposition process  

NASA Astrophysics Data System (ADS)

We have synthesized Pb(Zr0.52Ti0.48)O3 fibres with diameters ranging from 500 nm to several microns using electrospinning and metallo-organic decomposition techniques (Wang et al 2002 Mater. Res. Soc. Symp. Proc. 702 359). By a refinement of our electrospinning technique, i.e. by increasing the viscosity of the precursor solution, and by adding a filter to the tip of the syringe, the diameter of the synthesized PZT fibres has been reduced to the neighbourhood of 100 nm. The complex thermal decomposition was characterized using Fourier-transform infrared (FTIR) spectroscopy and x-ray diffraction (XRD). It was found that alcohol evaporated during electrospinning and that most of the organic groups had pyrolysed before the intermediate pyrochlore phase was formed. There is a good correspondence between XRD and FTIR spectra. We also verify that a thin film of platinum coated on the silicon substrate catalyses the phase transformation of the pyrochlore into the perovskite phase.

Wang, Yu; Santiago-Avilés, Jorge J.

2004-01-01

135

Development and testing of a fast Fourier transform high dynamic-range spectral diagnostics for millimeter wave characterization  

SciTech Connect

A fast Fourier transform (FFT) based wide range millimeter wave diagnostics for spectral characterization of scattered millimeter waves in plasmas has been successfully brought into operation. The scattered millimeter waves are heterodyne downconverted and directly digitized using a fast analog-digital converter and a compact peripheral component interconnect computer. Frequency spectra are obtained by FFT in the time domain of the intermediate frequency signal. The scattered millimeter waves are generated during high power electron cyclotron resonance heating experiments on the TEXTOR tokamak and demonstrate the performance of the diagnostics and, in particular, the usability of direct digitizing and Fourier transformation of millimeter wave signals. The diagnostics is able to acquire 4 GHz wide spectra of signals in the range of 136-140 GHz. The rate of spectra is tunable and has been tested between 200 000 spectra/s with a frequency resolution of 100 MHz and 120 spectra/s with a frequency resolution of 25 kHz. The respective dynamic ranges are 52 and 88 dB. Major benefits of the new diagnostics are a tunable time and frequency resolution due to postdetection, near-real time processing of the acquired data. This diagnostics has a wider application in astrophysics, earth observation, plasma physics, and molecular spectroscopy for the detection and analysis of millimeter wave radiation, providing high-resolution spectra at high temporal resolution and large dynamic range.

Thoen, D. J.; Bongers, W. A.; Westerhof, E.; Baar, M. R. de; Berg, M. A. van den; Beveren, V. van; Goede, A. P. H.; Graswinckel, M. F.; Schueller, F. C. [Association EURATOM-FOM, Trilateral Euregio Cluster, FOM-Institute for Plasma Physics Rijnhuizen, P.O. Box 1207, 3430 BE Nieuwegein (Netherlands); Oosterbeek, J. W.; Buerger, A. [Association EURATOM-FZJ, Institut fuer Energieforschung-Plasmaphysik, Forschungszentrum Juelich GMBH, 52425 Juelich (Germany); Hennen, B. A. [Association EURATOM-FOM, Trilateral Euregio Cluster, FOM-Institute for Plasma Physics Rijnhuizen, P.O. Box 1207, 3430 BE Nieuwegein (Netherlands); Control Systems Technology Group, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven (Netherlands)

2009-10-15

136

Development and testing of a fast Fourier transform high dynamic-range spectral diagnostics for millimeter wave characterization  

NASA Astrophysics Data System (ADS)

A fast Fourier transform (FFT) based wide range millimeter wave diagnostics for spectral characterization of scattered millimeter waves in plasmas has been successfully brought into operation. The scattered millimeter waves are heterodyne downconverted and directly digitized using a fast analog-digital converter and a compact peripheral component interconnect computer. Frequency spectra are obtained by FFT in the time domain of the intermediate frequency signal. The scattered millimeter waves are generated during high power electron cyclotron resonance heating experiments on the TEXTOR tokamak and demonstrate the performance of the diagnostics and, in particular, the usability of direct digitizing and Fourier transformation of millimeter wave signals. The diagnostics is able to acquire 4 GHz wide spectra of signals in the range of 136-140 GHz. The rate of spectra is tunable and has been tested between 200 000 spectra/s with a frequency resolution of 100 MHz and 120 spectra/s with a frequency resolution of 25 kHz. The respective dynamic ranges are 52 and 88 dB. Major benefits of the new diagnostics are a tunable time and frequency resolution due to postdetection, near-real time processing of the acquired data. This diagnostics has a wider application in astrophysics, earth observation, plasma physics, and molecular spectroscopy for the detection and analysis of millimeter wave radiation, providing high-resolution spectra at high temporal resolution and large dynamic range.

Thoen, D. J.; Bongers, W. A.; Westerhof, E.; Oosterbeek, J. W.; de Baar, M. R.; van den Berg, M. A.; van Beveren, V.; Bürger, A.; Goede, A. P. H.; Graswinckel, M. F.; Hennen, B. A.; Schüller, F. C.

2009-10-01

137

Long-term batch study of sorption, transformation and extractability to characterize the fate of the veterinary antibiotic sulfadiazine  

NASA Astrophysics Data System (ADS)

The occurrence of veterinary antibiotic substances in various environmental compartments is of growing concern. Once released into the environment (e.g. via manure), these organic substances can cause changes in the composition of microbial populations, provoke the development and spreading of resistance genes and finally reach the food chain. The substance under study is the veterinary antibiotic sulfadiazine (SDZ), which belongs to the chemical group of the sulfonamides. These compounds are widely applied in animal husbandry. There are hardly any studies on the macroscopic sorption and desorption behaviour in combination with transformation processes, particularly investigating the sorbed fraction. We are conducting long-term batch sorption experiments to characterize the partitioning between the liquid and the solid phases as well as formation of transformation products. A sequential extraction procedure enables us to analyse the composition of the various sorbed fractions. We applied 14C-labelled SDZ in aqueous solution to fresh soil, originating from an agricultural field (silty loam). Adsorption and desorption studies are conducted for the duration of 60 d and 80 d, respectively. Unique setups for single time-steps allow us to trace the development of the partition process between the liquid and the solid phase and also partitioning within the solid phase. The composition of these liquid phases concerning the parent substance and the transformation products is analyzed. Using Radio-HPLC we find at least five transformation products: 4-hydroxy-sulfadiazine (4-OH-SDZ), 4-(2-iminopyrimidin-1(2H)-yl)-aniline (An-SDZ) and additionally three yet unknown products. By means of a sequential extraction, differently strong bound fractions of the compound can be distinguished. Extractions consist of a mild method (0.01 M CaCl2-solution; 24 h) followed by a methanol extraction (4 h). Finally, a residual fraction is gained by microwave extraction at an elevated temperature (150°C) and pressure (mixture of water and acetonitril, 4:1). Bound residues are determined by combustion. The course of the kinetic adsorption/desorption processes as well as the partitioning of the compound over the various solid phase fractions is observed. Sorption is time-dependent and strongly non-linear. The topsoil shows a significantly higher sorption affinity than the subsoil. While the amount of radioactivity sorbed to the soil matrix increases with time, the extractability decreases significantly, i. e. at the end of the experimental time there is no yield with mild extraction methods. On the contrary, after 60 d, there is still a considerably mass gained with the microwave extraction. Desorption is very slow due to hysteresis. In the topsoil transformation occurs with higher rates, leading to more detectable transformation products as in the subsoil. With our experimental setup it will be possible to set up a kinetic modell for the partitioning of the solute between the liquid and the solid phase. This description will also include an estimation of the transformation parameters.

Sittig, Stephan; Kasteel, Roy; Groeneweg, Joost; Vereecken, Harry

2010-05-01

138

Fabrication and characterization of rectangular thin film planar loops for transformer applications  

NASA Astrophysics Data System (ADS)

This study focuses on optimizing the configuration and performance of a thin film planar loop that is flux linked to a short straight wire. Our calculations for the mutual inductance show its dependence on the geometry of the planar loop as well as on its location relative to the wire. We have fabricated and characterized various geometries and compared the data to the solutions predicted by our model. These results are used in designing the next generation of devices which will incorporate magnetic nanoparticles.

Topasna, Gregory A.; Topasna, Daniela M.; Powell, Frank R.

2009-03-01

139

Ultrasonic characterization of soft tissue vibrations based on the two-dimensional Fourier transform  

NASA Astrophysics Data System (ADS)

It has recently been demonstrated that soft tissue vibrations in the body, traditionally associated with vascular bruits and cardiac murmurs, can potentially be used for the ultrasonic diagnosis of coronary artery disease and vascular trauma. In this paper, the ultrasonic spectrum of soft tissue vibrations is formulated using the two-dimensional Fourier transform, making full use of the information present in the backscattered ultrasound echoes from vibrating tissue. Parametric simulation studies show that vibrations with amplitude 1 ?m may be detected even with tissue velocity of 20 cm/s and acceleration of 5 m/s2, e.g., during peak cardiac motion. Vibrations with amplitude as low as 0.1 ?m may be detected when the tissue acceleration is negligible, e.g., during mid-diastole. Also, it was found that tissue vibrations in a direction transverse to the ultrasound beam can be detected. In vivo examples of cardiac wall vibrations in patients with coronary artery disease are presented. Tissue vibrations can provide improved sensitivity over conventional duplex ultrasound since the scattering strength from tissue is significantly higher than that from blood. In addition, detection of tissue vibrations has reduced angle dependency and does not require visualization of the vessel lumen, making the exam less dependent on operator skill.

Sikdar, Siddhartha; Kim, Yongmin; Beach, Kirk W.

2005-09-01

140

Fourier transform infrared absorption spectroscopy characterization of gaseous atmospheric pressure plasmas with 2 mm spatial resolution  

SciTech Connect

This paper describes an optical setup built to record Fourier transform infrared (FTIR) absorption spectra in an atmospheric pressure plasma with a spatial resolution of 2 mm. The overall system consisted of three basic parts: (1) optical components located within the FTIR sample compartment, making it possible to define the size of the infrared beam (2 mm Multiplication-Sign 2 mm over a path length of 50 mm) imaged at the site of the plasma by (2) an optical interface positioned between the spectrometer and the plasma reactor. Once through the plasma region, (3) a retro-reflector module, located behind the plasma reactor, redirected the infrared beam coincident to the incident path up to a 45 Degree-Sign beamsplitter to reflect the beam toward a narrow-band mercury-cadmium-telluride detector. The antireflective plasma-coating experiments performed with ammonia and silane demonstrated that it was possible to quantify 42 and 2 ppm of these species in argon, respectively. In the case of ammonia, this was approximately three times less than this gas concentration typically used in plasma coating experiments while the silane limit of quantification was 35 times lower. Moreover, 70% of the incoming infrared radiation was focused within a 2 mm width at the site of the plasma, in reasonable agreement with the expected spatial resolution. The possibility of reaching this spatial resolution thus enabled us to measure the gaseous precursor consumption as a function of their residence time in the plasma.

Laroche, G. [Laboratoire d'Ingenierie de Surface, Centre de Recherche sur les Materiaux Avances, Departement de genie des mines, de la metallurgie et des materiaux, Universite Laval, 1065, avenue de la Medecine, Quebec G1V 0A6 (Canada); Centre de recherche du CHUQ, Hopital St Francois d'Assise, 10, rue de l'Espinay, local E0-165, Quebec G1L 3L5 (Canada); Vallade, J. [Laboratoire Procedes, Materiaux et Energie Solaire, PROMES, CNRS, Technosud, Rambla de la Thermodynamique, F-66100 Perpignan (France); Agence de l'environnement et de la Ma Latin-Small-Letter-Dotless-I -carettrise de l'Energie, 20, avenue du Gresille, BP 90406, F-49004 Angers Cedex 01 (France); Bazinette, R.; Hernandez, E.; Hernandez, G.; Massines, F. [Laboratoire Procedes, Materiaux et Energie Solaire, PROMES, CNRS, Technosud, Rambla de la Thermodynamique, F-66100 Perpignan (France); Nijnatten, P. van [OMT Solutions bv, High Tech Campus 9, 5656AE Eindhoven (Netherlands)

2012-10-15

141

Characterizing the transformation and transfer of nitrogen during the aerobic treatment of organic wastes and digestates  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Ammonia emissions varied depending on the nature of wastes and the treatment conditions. Black-Right-Pointing-Pointer Nitrogen losses resulted from ammonia emissions and nitrification-denitrification. Black-Right-Pointing-Pointer Ammonification can be estimated from biodegradable carbon and carbon/nitrogen ratio. Black-Right-Pointing-Pointer Ammonification was the main process contributing to N losses. Black-Right-Pointing-Pointer Nitrification rate was negatively correlated to stripping rate of ammonia nitrogen. - Abstract: The transformation and transfer of nitrogen during the aerobic treatment of seven wastes were studied in ventilated air-tight 10-L reactors at 35 Degree-Sign C. Studied wastes included distinct types of organic wastes and their digestates. Ammonia emissions varied depending on the kind of waste and treatment conditions. These emissions accounted for 2-43% of the initial nitrogen. Total nitrogen losses, which resulted mainly from ammonia emissions and nitrification-denitrification, accounted for 1-76% of the initial nitrogen. Ammonification was the main process responsible for nitrogen losses. An equation which allows estimating the ammonification flow of each type of waste according to its biodegradable carbon and carbon/nitrogen ratio was proposed. As a consequence of the lower contribution of storage and leachate rates, stripping and nitrification rates of ammonia nitrogen were negatively correlated. This observation suggests the possibility of promotingnitrification in order to reduce ammonia emissions.

Zeng Yang, E-mail: yang.zeng@irstea.fr [Irstea, UR GERE, 17 avenue de Cucille, CS 64427, F-35044 Rennes Cedex (France); Universite Europeenne de Bretagne, F-35000 Rennes (France); Guardia, Amaury de; Daumoin, Mylene; Benoist, Jean-Claude [Irstea, UR GERE, 17 avenue de Cucille, CS 64427, F-35044 Rennes Cedex (France)

2012-12-15

142

Fourier transform infrared absorption spectroscopy characterization of gaseous atmospheric pressure plasmas with 2 mm spatial resolution.  

PubMed

This paper describes an optical setup built to record Fourier transform infrared (FTIR) absorption spectra in an atmospheric pressure plasma with a spatial resolution of 2 mm. The overall system consisted of three basic parts: (1) optical components located within the FTIR sample compartment, making it possible to define the size of the infrared beam (2 mm × 2 mm over a path length of 50 mm) imaged at the site of the plasma by (2) an optical interface positioned between the spectrometer and the plasma reactor. Once through the plasma region, (3) a retro-reflector module, located behind the plasma reactor, redirected the infrared beam coincident to the incident path up to a 45° beamsplitter to reflect the beam toward a narrow-band mercury-cadmium-telluride detector. The antireflective plasma-coating experiments performed with ammonia and silane demonstrated that it was possible to quantify 42 and 2 ppm of these species in argon, respectively. In the case of ammonia, this was approximately three times less than this gas concentration typically used in plasma coating experiments while the silane limit of quantification was 35 times lower. Moreover, 70% of the incoming infrared radiation was focused within a 2 mm width at the site of the plasma, in reasonable agreement with the expected spatial resolution. The possibility of reaching this spatial resolution thus enabled us to measure the gaseous precursor consumption as a function of their residence time in the plasma. PMID:23126767

Laroche, G; Vallade, J; Bazinette, R; van Nijnatten, P; Hernandez, E; Hernandez, G; Massines, F

2012-10-01

143

Development of imaging Fourier-transform spectroscopy for the characterization of turbulent jet flames  

NASA Astrophysics Data System (ADS)

Recent advances in computational models to simulate turbulent, reactive flow fields have outpaced the ability to collect highly constraining data---throughout the entire flow field---for validating and improving such models. In particular, the ability to quantify in three dimensions both the mean scalar fields (i.e. temperature & species concentrations) and their respective fluctuation statistics via hyperspectral imaging would be a game-changing advancement in combustion diagnostics, with high impact in both validation and improvement efforts for computational combustion models. This research effort establishes imaging Fourier- transform spectrometry (IFTS) as a valuable tool (which complements laser diagnostics) for the study of turbulent combustion. Specifically, this effort (1) demonstrates that IFTS can be used to quantitatively measure spatially resolved spectra from a canonical turbulent flame; (2) establishes the utility of quantile spectra in first-ever quantitative comparisons between measured and modeled turbulent radiation interaction (TRI); (3) develops a simple onion-peeling-like spectral inversion methodology suitable for estimating radial scalar distributions in axisymmetric, optically-thick flames; (4) builds understanding of quantile spectra and demonstrates proof of concept for their use in estimating scalar fluctuation statistics.

Harley, Jacob L.

144

Characterization of Transformation Temperatures with the Bend and Free Recovery Technique: Parameters and Effects  

NASA Astrophysics Data System (ADS)

This study was conducted to investigate factors such as the deformation strain, straining temperature, and the number of testing cycles on the measurement of transformation temperatures using the bend and free recovery (BFR) technique. Ti-56.0%Ni wire with approximately 40% cold work and a 2 mm diameter was heat treated in an air furnace for 10 min at 490 °C to obtain an A f of approximately 21 °C. Wire specimens were deformed with one of two mandrels to apply an outer fiber strain of 2.4 or 5.8%. Deformation was performed at one of four straining temperatures: 0, -30, -50, or -65 °C. Specimens were tested ten times to investigate the effect of repeated testing. The resulting BFR curves were analyzed to determine the trends in the R-phase start ( R_{{text{s}}}^' ) and austenite finish ( A f) temperatures. For specimens strained at both 2.4 and 5.8% there was no detectable change in A f resulting from changes in the deformation temperature. Increasing the deformation strain from 2.4 to 5.8% tended to increase the measured A f by approximately 1 °C independent of deformation temperature. Repeat testing seemed to result in a slight increase in A f but the intrinsic scatter of the BFR data made it impossible to conclusively identify a trend.

Drexel, Masao; Proft, Jim; Russell, Scott

2009-08-01

145

Multi-responsive polypeptidosome: characterization, morphology transformation, and triggered drug delivery.  

PubMed

The biodegradable polymeric nanomedicines that may be integrated with multi-stimuli-sensitivity to achieve triggered or on-demand drug release kinetics are challenging for polymer therapeutics and drug delivery systems. By controlling the structure transformation of one polypeptide-b-PEO copolymer, a novel multi-responsive polypeptide-based vesicle (polypeptidosome) presents the combined sensitivity of multiple physiological and clinic-related stimuli, and both morphology and size of the polypeptidosome are changed during the triggered process. The designer polypeptide has unique structures composed of 1) light-responsive o-nitrobenzyl groups, 2) oxidizable thioether linkers, 3) photo-caged redox thiol groups on parent poly(L-cysteine), and 4) tunable conformation, which enable the polypeptidosome to have a peculiar multi-response. The anticancer drug doxorubicin can be released in a controlled or on-off manner. The combination stimuli of UV irradiation and H2 O2 oxidation induces a large effect and a lower IC50 of 3.80 ?g doxorubicin (DOX) equiv/mL compared to 5.28 ?g DOX equiv/mL of individual H2 O2 trigger. PMID:25170968

Liu, Gang; Zhou, Linzhu; Guan, Yanfei; Su, Yue; Dong, Chang-Ming

2014-10-01

146

Cotton fiber quality characterization with light scattering and fourier transform infrared techniques.  

PubMed

Fiber quality measurement is critical to assessing the value of a bale of cotton for various textile purposes. An instrument that could measure numerous cotton quality properties by optical means could be made simpler and faster than current fiber quality measurement instruments, and it might be more amenable to on-line measurement at processing facilities. To that end, a laser system was used to investigate cotton fiber samples with respect to electromagnetic scattering at various wavelengths, polarization angles, and scattering angles. A Fourier transform infrared (FT-IR) instrument was also used to investigate the transmission of electromagnetic energy at various mid-infrared wavelengths. Cotton samples were selected to represent a wide range of micronaire values. Varying the wavelength of the laser at a fixed polarization resulted in little variation in scattered light among the cotton samples. However, varying the polarization at a fixed wavelength produced notable variation, indicating that polarization might be used to differentiate among cotton samples with respect to certain fiber properties. The FT-IR data in the 12 to 22 microm range produced relatively large differences in the amount of scattered light among all samples, and FT-IR data at certain combinations of fixed wavelengths were highly linearly related to certain measures of cotton quality including micronaire. PMID:19281648

Thomasson, J A; Manickavasagam, S; Mengüç, M P

2009-03-01

147

Characterization of naphthenic acids by gas chromatography-Fourier transform ion cyclotron resonance mass spectrometry.  

PubMed

During the bitumen extraction from the oil sands of Alberta, large volumes of process water containing naphthenic acids are stored in tailing ponds. The naphthenic acids along with other components in the processed waters are known to be toxic in aquatic environments. In view of the complex matrix and the toxicity of the processed waters, there is a need for complementary analytical techniques for comprehensive characterization of the naphthenic acid mixtures. This study reports the online gas chromatographic separation of naphthenic acid mixtures prior to ultrahigh resolution mass spectrometry detection, using electron and chemical ionization. Two oil sands processed water samples and two groundwater samples were characterized to evaluate the performance of the instrumental technique. The high mass resolution of the system enabled visualization of the data using Kendrick mass defect plots. The addition of gas chromatographic separations enabled visualization of the data as unique compound class elution fingerprints. The technique is demonstrated to be a valuable tool for chemical fingerprinting of naphthenic acids. PMID:25001115

Ortiz, Xavier; Jobst, Karl J; Reiner, Eric J; Backus, Sean M; Peru, Kerry M; McMartin, Dena W; O'Sullivan, Gwen; Taguchi, Vince Y; Headley, John V

2014-08-01

148

Experimental characterization of heterogeneous deformation due to phase transformations, twinning, and slip deformation using digital image correlation  

NASA Astrophysics Data System (ADS)

In traditional continuum plasticity models, deformation heterogeneities are averaged out above the length scale of a representative volume element (RVE). Below this length scale, heterogeneities are permitted but must average out over the volume of the RVE. This is the so-called homogenization technique. In recent years, the emergence of systematic experimental investigations and numerical simulations have challenged traditional continuum plasticity models, which suggest homogeneous loads produce spatially homogeneous deformations in the absence of plastic instabilities. Knowledge of strain heterogeneities is important to enhance the performance of engineering devices and components. For example, as devices and components are miniaturized, strain heterogeneities may lead to structural instability, or even product failure. Manufacturing difficulties such as those commonly found in metal forming operations which include tearing, necking, edge cracking, and surface roughening are often attributed to heterogeneous deformation. It is also speculated that strain heterogeneities may develop into fatigue damage initiation sites as well as corrosion sites. The current work is focused on characterizing the spatial strain heterogeneity due to phase transformations, twinning, and slip deformation. Using digital image correlation to obtain full-field strain measurements at multiple length scales (ranging from micrometer to millimeter), it was shown that despite uniform microstructures and boundary conditions, each deformation mechanism manifested heterogeneously. Specifically, increasing strain heterogeneity was observed concurrent with decreasing the measurement length scale. It is shown that an appropriate length scale to obtain measurements can be determined for phase transformations, and twinning deformation, but not for slip deformation. No inherent length scale could be determined for slip deformation because no discrete boundaries between slipped and un-slipped domains exist. Slip deformation appears to have a spatial correlation, and seems to obey a power-law relationship. Thus, for slip deformation, changing the length scale does not change the measurement in a one-to-one fashion whereas for phase transformations and twinning deformation it does. These multiscale measurements were used to discuss: the transformation sequence, nuances of the stress-strain curve such as strain hardening and softening, the hysteretic behavior, the strain-rate dependence, twinning strain, twin-twin intersections, twin fraction evolution, dynamic strain aging, grain interactions, mesoscopic slip bands, and a RVE size.

Efstathiou, Christos

149

Parametric study and characterization of the isobaric thermomechanical transformation fatigue of nickel-rich NiTi SMA actuators  

NASA Astrophysics Data System (ADS)

The recent development of various aerospace applications utilizing Ni-rich NiTi Shape memory Alloys (SMAs) as actuators motivated the need to characterize the cyclic response and the transformation fatigue behavior of such alloys. The fatigue life validation and certification of new designs is required in order to be implemented and used in future applications. For that purpose, a custom built fatigue test frame was designed to perform isobaric thermally induced transformation cycles on small dogbones SMA actuators (test gauge cross-section up to: 1.270 x 0.508 mm2). A parametric study on the cyclic response and transformation fatigue behavior of Ni-rich NiTi SMAs led to the optimization of several material/process and test parameters, namely: the applied stress range, the heat treatment, the heat treatment environment and the specimen thickness. However, fatigue testing was performed in a chilled waterless glycol environment maintained at a temperature of 5°C that showed evidence of corrosion-assisted transformation fatigue failure. Therefore, it was necessary to build a fatigue test frame that would employ a dry and inert cooling methodology to get away from any detrimental interactions between the specimens and the cooling medium (corrosion). The selected cooling method was gaseous nitrogen, sprayed into a thermally insulated chamber, maintaining a temperature of -20°C. The design of the gaseous nitrogen cooling was done in such a way that the actuation frequency is similar to the one obtained using the original design (~ 0.1 Hz). For both cooling methods, Joule resistive heating was used to heat the specimens. In addition and motivated by the difference in surface quality resulting from different material processing such as EDM wire cutting and heat treatments, EDM recast layer and oxide layer were removed. The removal was followed by an ultra-fine polish (0.05 ?m) that was performed on a subset of the fatigue specimens. Experimental results are presented for full actuation of the SMA actuators and are given in terms of applied stress, accumulated plastic strain and number of cycles to failure. In addition, the assessment of the influence of the surface quality is supported by fatigue tests results and post-failure microstructure analysis.

Bertacchini, Olivier W.; Schick, Justin; Lagoudas, Dimitris C.

2009-03-01

150

Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometric characterization of high molecular mass Starburst(TM) dendrimers  

NASA Astrophysics Data System (ADS)

A series of Starburst(TM) polyamidoamine (PAMAM) dendrimers, built from a tetrafunctional ethylenediamine (EDA) core, generations 1 to 10 (G1-G10), and covering a wide range of charge state distributions (i.e. from m / z ~ 500 to m / z ~ 15 000), have been investigated by electrospray ionization (ESI) Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. High resolution mass spectra for lower generation dendrimers (G1, Mr ~ 1429 u to G5, Mr ~ 28 825 u) allowed characterization of the polydispersity of these systems, providing a basis for improving synthetic strategies and characterizing surface-modified dendrimers. The relationship between charge state in the gas phase and molecular mass of these spherical macromolecules is reported and used to estimate the stoichiometry of a G5 PAMAM dendrimer -- polyclonal rabbit IgG immunoconjugate. The results presented herein represent the highest molecular mass species yet detected by FT-ICR MS with the exception of measurements based upon individual ion detection.

Tolic, Ljiljana Paa; Anderson, Gordon A.; Smith, Richard D.; Brothers, Herbert M.; Spindler, Ralph; Tomalia, Donald A.

1997-11-01

151

Characterization of full-scale carbon contactors for siloxane removal from biogas using online Fourier transform infrared spectroscopy.  

PubMed

In this study, online Fourier transform infrared (FTIR) spectroscopy has been used to generate the first comprehensive characterization of full-scale carbon contactors for siloxane removal from biogas. Using FTIR, two clear operational regions within the exhaustion cycle were evidenced: an initial period of pseudo-steady state where the outlet siloxane concentration was consistently below the proposed siloxane limits; and a second period characterized by a progressive rise in outlet siloxane concentration during and after breakthrough. Due to the sharp breakthrough front identified, existing detection methods (which comprise field sampling coupled with laboratory-based chromatographic determination) are insufficiently responsive to define breakthrough, thus carbon contactors currently remain in service while providing limited protection to the combined heat and power engine. Integration of the exhaustion cycle to breakthrough identified average specific media capacities of 8.5-21.5 gsiloxane [Formula: see text], which are lower than that has been reported for vapour phase granular activated carbon (GAC). Further speciation of the biogas phase identified co-separation of organic compounds (alkanes and aromatics), which will inevitably reduce siloxane capacity. However, comparison of the five full-scale contactors identified that greater media capacity was accessible through operating contactors at velocities sufficient to diminish axial dispersion effects. In addition to enabling significant insight into gas phase GAC contactors, the use of FTIR for online control of GAC for siloxane removal is also presented. PMID:25413112

Hepburn, C A; Martin, B D; Simms, N; McAdam, E J

2015-01-01

152

New way to characterize the percolation threshold of polyethylene and carbon nanotube polymer composites using Fourier transform (FT) rheology  

NASA Astrophysics Data System (ADS)

In this article, a new way to characterize the percolation threshold of polymer nanocomposites made of polyethylene (PE) with single and multi walled carbon nanotubes (SWCNTs and MWCNTs) is presented. Small and large oscillatory shear (SAOS and LAOS) experiments were performed to characterize the degree of dispersion and percolation threshold. The analysis of the stress response in the LAOS regime as a function of the applied deformation amplitude and frequency was performed using Fourier Transform (FT)-Rheology. The zero strain intrinsic nonlinear parameter, Q0(?), was calculated by extrapolation of I3/1(?0, ?) and was, used to quantify the nonlinearity measured by FT-Rheology. Interestingly, a drop in Q0 as a function of the CNT weight fraction at a fixed frequency was found that was below the percolation threshold. This was followed by, a steep rise in Q0 above the percolation threshold. Therefore, the new method based on this observation that is proposed and described with this article has the potential to lead to a better understanding of structure-property relationships in polymer nanocomposites.

Ahirwal, Deepak; Palza, Humberto; Schlatter, Guy; Wilhelm, Manfred

2014-08-01

153

Proc. of the 24th IEEE Photovoltaic Specialists Conference (IEEE, New York, 1995), pp. 291-294. ADMITTANCE MEASUREMENTS ON Cu(In,Ga)Se2 POLYCRYSTALLINE THIN-  

E-print Network

-294. ADMITTANCE MEASUREMENTS ON Cu(In,Ga)Se2 POLYCRYSTALLINE THIN- FILM SOLAR CELLS John H. Scofield Physics) and Cu(In,Ga)Se2 (CIGS) absorber layer depositions. Samples were fabricated at the National Renewable Energy Laboratory (NREL) on soda-lime glass substrates with the usual n+-ZnO/i-Zn

Scofield, John H.

154

Bio-telemetric device for measurement of left ventricular pressure-volume loops using the admittance technique in conscious, ambulatory rats  

PubMed Central

This paper presents the design, construction and testing of a device to measure pressure volume loops in the left ventricle of conscious, ambulatory rats. Pressure is measured with a standard sensor, but volume is derived from data collected from a tetrapolar electrode catheter using a novel admittance technique. There are two main advantages of the admittance technique to measure volume. First, the contribution from the adjacent muscle can be instantaneously removed. Second, the admittance technique incorporates the nonlinear relationship between the electric field generated by the catheter and the blood volume. A low power instrument weighing 27 g was designed, which takes pressure-volume loops every 2 minutes and runs for 24 hours. Pressure-volume data are transmitted wirelessly to a base station. The device was first validated in thirteen rats with an acute preparation with 2-D echocardiography used to measure true volume. From an accuracy standpoint, the admittance technique is superior to both the conductance technique calibrated with hypertonic saline injections, and calibrated with cuvettes. The device was then tested in six rats with a 24-hour chronic preparation. Stability of the animal preparation and careful calibration are important factors affecting the success of the device. PMID:21606560

Raghavan, Karthik; Feldman, Marc D; Porterfield, John E; Larson, Erik R; Jenkins, J Travis; Escobedo, Daniel; Pearce, John A

2011-01-01

155

A novel high-performance fourier transform ion cyclotron resonance cell for improved biopolymer characterization.  

PubMed

A new trapped ion cell design for use with Fourier transform ion cyclotron resonance mass spectrometry is described. The design employs 15 cylindrical ring electrodes to generate trapping potential wells and 32 separately assignable rod electrodes for excitation and detection. The rod electrodes are positioned internal to the ring electrodes and provide excitation fields that are thereby linearized along the magnetic field over the entire trapped ion volume. The new design also affords flexibility in the shaping of the trapping field using the 15 ring electrodes. Many different trapping well shapes can be generated by applying different voltages to the individual ring electrodes, ranging from quadratic to linearly ramped along the magnetic field axis, to a shape that is nearly flat over the entire trap volume, but rises very steeply near the ends of the trap. This feature should be useful for trapping larger ion populations and extension of the useful range of ion manipulation and dissociation experiments since the number of stages of ion manipulation or dissociation is limited in practice by the initial trapped ion population size. Predicted trapping well shapes for two different ring electrode configurations are presented, and these and several other possible configurations are discussed, as are the predicted excitation fields based on the use of rod electrodes internal to the trapping ring electrodes. Initial results are presented from an implementation of the design using a 3.5 T superconducting magnet. It was found that ions can be successfully trapped and detected with this cell design and that selected ion accumulation can be performed with the utilization of four rods for quadrupolar excitation. The initial results presented here illustrate the feasibility of this cell design and demonstrate differences in observed performance based upon different trapping well shapes. PMID:10633238

Bruce, J E; Anderson, G A; Lin, C Y; Gorshkov, M; Rockwood, A L; Smith, R D

2000-01-01

156

Spectral Characterizations of the Clouds and the Earth's Radiant Energy System (CERES) Thermistor Bolometers using Fourier Transform Spectrometer (FTS) Techniques  

NASA Technical Reports Server (NTRS)

Fourier Transform Spectrometer (FTS) techniques are being used to characterize the relative spectral response, or sensitivity, of scanning thermistor bolometers in the infrared (IR) region (2 - >= 100-micrometers). The bolometers are being used in the Clouds and the Earth's Radiant Energy System (CERES) program. The CERES measurements are designed to provide precise, long term monitoring of the Earth's atmospheric radiation energy budget. The CERES instrument houses three bolometric radiometers, a total wavelength (0.3- >= 150-micrometers) sensor, a shortwave (0.3-5-micrometers) sensor, and an atmospheric window (8-12-micrometers) sensor. Accurate spectral characterization is necessary for determining filtered radiances for longwave radiometric calibrations. The CERES bolometers spectral response's are measured in the TRW FTS Vacuum Chamber Facility (FTS - VCF), which uses a FTS as the source and a cavity pyroelectric trap detector as the reference. The CERES bolometers and the cavity detector are contained in a vacuum chamber, while the FTS source is housed in a GN2 purged chamber. Due to the thermal time constant of the CERES bolometers, the FTS must be operated in a step mode. Data are acquired in 6 IR spectral bands covering the entire longwave IR region. In this paper, the TRW spectral calibration facility design and data measurement techniques are described. Two approaches are presented which convert the total channel FTS data into the final CERES spectral characterizations, producing the same calibration coefficients (within 0.1 percent). The resulting spectral response curves are shown, along with error sources in the two procedures. Finally, the impact of each spectral response curve on CERES data validation will be examined through analysis of filtered radiance values from various typical scene types.

Thornhill, K. Lee; Bitting, Herbert; Lee, Robert B., III; Paden, Jack; Pandey, Dhirendra K.; Priestley, Kory J.; Thomas, Susan; Wilson, Robert S.

1998-01-01

157

Characterization of biomass burning: Fourier transform infrared analysis of wood and vegetation combustion products  

NASA Astrophysics Data System (ADS)

The Fourier transform infrared examination of the combustion products of a selection of forest materials has been undertaken in order to guide future detection of biomass burning using satellite remote sensing. Combustion of conifer Pinus strobus (white pine) and deciduous Prunus serotina (cherry), Acer rubrum (red maple), Friglans nigra (walnut), Fraxinus americana (ash), Betula papyrifera (birch), Querus alba (white oak) and Querus rubra (red oak) lumber, in a Meeker burner flame at temperatures of 400 to 900 degrees Fahrenheit produces a broad and relatively flat signal with a few distinct peaks throughout the wavelength spectra (400 to 4000 cm-1). The distinct bands located near wavelengths of 400-700, 1500-1700, 2200-2400 and 3300-3600 cm-1 vary in intensity with an average difference between the highest and lowest absorbing species of 47 percent. Spectral band differences of 10 percent are within the range of modern satellite spectrometers, and support the argument that band differences can be used to discriminate between various types of vegetation. A similar examination of soot and smoke derived from the leaves and branches of the conifer Pinus strobus and deciduous Querus alba (white oak), Querus rubra (red oak), Liquidambar styraciflua (sweetgum), Acer rubrum (maple) and Tilea americana (American basswood) at combustion temperatures of 400 to 900 degrees Fahrenheit produce a similar broad spectrum with a shift in peak location occurring in peaks below the 1700 cm-1 wavelength. The new peaks occur near wavelengths of 1438-1444, 875 and 713 cm-1. This noted shift in wavelength location may be indicative of a fingerprint region for green woods distinguishable from lumber through characteristic biomass suites. Temperature variations during burning show that the spectra of low temperature smoldered aerosols, occurring near 400 to 450 degrees Fahrenheit, may be distinguished from higher temperature soot aerosols that occur above 600 degrees Fahrenheit. A heightened peak intensity of 50 percent is observed throughout the spectra of the lower temperature generated soot and smoke, with respect to the higher temperature generated soot and smoke. These observations suggest the possibility of establishing biomass reduction markers using a ratio method.

Padilla, Diomaris

158

Physical Characterization of human centromeric regions using transformation-associated recombination cloning technology  

SciTech Connect

A special interest in the organization of human centromeric DNA was stimulated a few years ago when two independent groups succeeded in reconstituting a functional human centromere, using constructs carrying centromere-specific alphoid DNA arrays. This work demonstrated the importance of DNA components in mammalian centromeres and opened a way for studying the structural requirements for de novo kinetochore formation and for construction of human artificial chromosomes (HACs) with therapeutic potential. To elucidate the structural requirements for formation of HACs with a functional kinetochore, we developed a new method for cloning of large DNA fragments for human centromeric regions that can be used as a substrate for HAC formation. This method exploits in vivo recombination in yeast (TAR cloning). In addition, a new strategy for the construction of alphoid DNA arrays was developed in our lab. The strategy involves the construction of uniform or hybrid synthetic alphoid DNA arrays by the RCA-TAR technique. This technique comprises two steps: rolling circle amplification of an alphoid DNA dimer and subsequent assembling of the amplified fragments by in vivo homologous recombination in yeast (Figure 1). Using this system, we constructed a set of different synthetic alphoid DNA arrays with a predetermined sequence varying in size from 30 to 140 kb and demonstrated that some of the arrays are competent in HAC formation. Because any nucleotide can be changed in a dimer before its amplification, this new technique is optimal for identifying the structural requirements for de novo kinetochore formation in HACs. Moreover, the technique makes possible to introduce into alphoid DNA arrays recognition sites for DNA-binding proteins. We have made the following progress on the studying of human centromeric regions using transformation-associated recombination cloning technology: i) minimal size of alphoid DNA array required for de novo kinetochore formation was estimated; ii) critical role of CENP-B binding site in do novo kinetochore formation was demonstrated; iii) role of gamma-satellite DNA in functional centromere was elucidated; iv) new generation of HAC with a conditional centromere was constructed for the study of epigenetic control of kinetochore function and for gene expression studies. These studies de novo kinetochore formation may thus provide both a fundamental knowledge and new points of intervention for therapy.

Vladimir Larionov, Ph D

2007-06-05

159

Secondary organic aerosol (trans)formation through aqueous phase guaiacol photonitration: chemical characterization of the products  

NASA Astrophysics Data System (ADS)

One of the largest primary sources of organic aerosol in the atmosphere is biomass burning (BB) (Laskin et al. 2009); in Europe its contribution to annual mean of PM10 is between 3 and 14 % (Maenhaut et al. 2012). During the process of wood burning many different products are formed via thermal degradation of wood lignin. Hardwood burning produces mainly syringol (2,6-dimetoxyphenol) derivatives, while softwood burning exclusively guaiacol (2-methoxyphenol) and its derivatives. Taking into account physical properties of methoxyphenols only, their concentrations in atmospheric waters might be underestimated. So, their aqueous phase reactions can be an additional source of SOA, especially in regions under significant influence of wood combustion. An important class of compounds formed during physical and chemical aging of the primary BBA in the atmosphere is nitrocatechols, known as strong absorbers of UV and Vis light (Claeys et al. 2012). Very recently, methyl-nitrocatechols were proposed as suitable markers for highly oxidized secondary BBA (Iinuma et al. 2010, Kitanovski et al. 2012). In the present work, the formation of SOA through aqueous phase photooxidation and nitration of guaiacol was examined. The key objective was to chemically characterize the main low-volatility products and further to check their possible presence in the urban atmospheric aerosols. The aqueous phase reactions were performed in a thermostated reactor under simulated sunlight in the presence of H2O2 and nitrite. Guaiacol reaction products were first concentrated by solid-phase extraction (SPE) and then subjected to semi-preparative liquid chromatography.The main product compounds were fractionated and isolated as pure solids and their structure was further elucidated by using nuclear magnetic resonance spectroscopy (1H, 13C and 2D NMR) and direct infusion negative ion electro-spray ionization tandem mass spectrometry (( )ESI-MS/MS). The main photonitration products of guaiacol (4-nitroguaiacol, 6-nitroguaiacol and 4,6-dinitroguaiacol) were examined for their presence in winter aerosol samples by using an optimized HPLC-(-)ESI-MS/MS. 4-nitroguaiacol and 4,6-dinitroguaiacol were unambiguously identified in winter PM10 from Ljubljana, Slovenia, whereas the absence of 6-nitroguaiacol was further explained with the help of long-term reaction monitoring. To our knowledge, our study represents the first report on the identification of 4,6-dinitroguaiacol in ambient aerosols. Laskin, A. et al. (2009) Environ. Sci. Technol. 43, 3764-3771. Maenhaut, W. et al. (2012) Sci. Tot. Environ. 437, 226-236. Claeys, M. et al. (2012) Environ. Chem. 9, 273-284. Iinuma, Y. et al. (2010) Environ. Sci. Technol. 44, 8453-8459. Kitanovski, Z. et al. (2012)J. Chromatogr. A 1268, 35-43.

Grgi?, Irena; Kitanovski, Zoran; Krofli?, Ana; ?usak, Alen

2014-05-01

160

Synthesis and characterization of catalysts for the selective transformation of biomass-derived materials  

NASA Astrophysics Data System (ADS)

The experimental work in this thesis focuses on generating catalysts for two intermediate processes related to the thermal conversion of lignocellulosic biomass: the synthesis and characterization of mesoporous silica supported cobalt catalysts for the Fischer-Tropsch reaction, and an exploration of the reactivity of bulk and supported molybdenum-based nitride catalysts for the hydrodeoxygenation (HDO) of guaiacol, a lignin model compound. The first section of the work details the synthesis of a series of silica-supported cobalt Fischer-Tropsch catalysts with pore diameters ranging from 2-23 nm. Detailed X-ray diffraction measurements were used to determine the composition and particle diameters of the metal fraction, analyzed as a three-phase system containing Cofcc, Cohcp and CoO particles. Catalyst properties were determined at three stages in catalyst history: (1) after the initial calcination step to thermally decompose the catalyst precursor into Co3O4, (2) after the hydrogen reduction step to activate the catalyst to Co and (3) after the FT reaction. From the study, it was observed that larger pore diameters supported higher turnover frequency; smaller pore diameters yielded larger mole fraction of CoO; XRD on post-reduction and post-FTS catalyst samples indicated significant changes in dispersivity after reduction. In the next section, the catalytic behaviors of unsupported, activated carbon-, alumina-, and SBA-15 mesoporous silica-supported molybdenum nitride catalysts were evaluated for the hydrodeoxygenation of guaiacol (2-methoxy phenol) at 300°C and 5 MPa. The nitride catalysts were prepared by thermal decomposition of bulk and supported ammonium heptamolybdate to form MoO 3 followed by nitridation in either flowing ammonia or a nitrogen/hydrogen mixture. The catalytic properties were strongly affected by the nitriding and purging treatment as well as the physical and chemical properties of support. The overall reaction was influenced by the crystalline phase present in the catalyst, dispersion of molybdenum nitride/oxynitride, and the porosity of the support. The hydrodeoxygenation of guaiacol followed two proposed reaction pathways: demethylation (DME) of guaiacol to form catechol, followed by dehydroxylation to form phenol; or a direct demethoxylation (DMO) to form phenol. The selectivity of the reaction was expressed in terms of the phenol/catechol ratio. Phenol was the predominant product for all the catalysts studied, except for the alumina-supported catalysts (an effect of the alumina support). The results from this thesis are encouraging for the application of Mo nitride based catalysts for hydrodeoxygenation of whole pyrolysis oil.

Ghampson, Isaac Tyrone

161

Modeling of a ring rosen-type piezoelectric transformer by Hamilton's principle.  

PubMed

This paper deals with the analytical modeling of a ring Rosen-type piezoelectric transformer. The developed model is based on a Hamiltonian approach, enabling to obtain main parameters and performance evaluation for the first radial vibratory modes. Methodology is detailed, and final results, both the input admittance and the electric potential distribution on the surface of the secondary part, are compared with numerical and experimental ones for discussion and validation. PMID:25881348

Nadal, Clement; Pigache, Francois; Erhart, Jiri

2015-04-01

162

Characterization of the basidiomycetes Thelephora ganbajun Zang and Termitomyces albuminosus (Berk.) Heim by Fourier transform infrared spectroscopy  

NASA Astrophysics Data System (ADS)

The basidiomycetes Thelephora ganbajun Zang and Termitomyces albuminosus (Berk.) Heim are two of the most favorite edible mushrooms in Yunnan Province, Southwest of China. In this paper, Fourier transform infrared speciroseopy (FTIR) was used to characterize the fruiting bodies of the two wild growing edible mushrooms. The results show that each mushroom has its characteristic infrared spectrum, in which the major peaks are attributed to proteins and polysaccharides. The spectra indicate that the poiysaccharides of the two mushrooms contain, both. ?- and ?-glycosidic linkage. A characteristic band of Thelephora ganbajun is an obvious band at about 1763 cm -1, which indicates that the mushroom contain oil. Differences are observed in the spectra of different parts of the fruiting body of Termitomyces albuminosus. According to the differences of the characteristic spectra peaks and absorbance ratios, the different parts of mushroom can be discriminated. The results suggest that the different species of mushrooms might be identified by the vibrational spectral features of the different parts of the fruiting bodies of mushrooms.

Liu, Gang; Song, Dingshan; Liu, Jian-hong; Zhao, Dezhang; Zhou, Yilan; Ou, Jiaming; Sun, Shizhong

2006-09-01

163

Satellite Characterization of Biomass Burning: Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope Study of Combustion Experiments  

NASA Astrophysics Data System (ADS)

Fourier Transform Infrared (FTIR) examination of the combustion products of selected forest materials using a meeker burner flame at temperatures up to 500 degrees Celsius produces a cluster of broad distinct peaks throughout the 400 to 4000 cm-1 wavenumber interval. Distinct bands bracketed by wavenumbers 400-700, 1500-1700, 2200-2400 and 3300-3600 cm-1 show variable intensity with an average difference between the least absorbing and most strongly absorbing species of approximately fifty percent. Given that spectral band differences of ten percent are within the range of modern satellite spectrometers, these band differences are of potential value for discriminating between fires that are impacting a range of vegetation types. Corresponding scanning electron microscope and energy dispersive micro-chemical (SEM/ED) analysis establishes that the evolved soot particles exhibit a characteristic rounded morphology, are carbon rich and host a wide range of adsorbed elements, including calcium, aluminum, potassium, silicon, sulfur and trace nitrogen. Combustion experiments involving leaves and branches as a subset of the biomass experiments at 200-500 degrees Celsius yield a similar broad background, but with peak shifts for maxima residing at less than 1700 cm-1. Additional peaks appear in the ranges 1438-1444, 875 and 713 cm-1. These peak are of potential use for discriminating between hot and smoldering fires, and between soot and smoke yields from green woods and whole-wood or lumber. The spectral shifts noted for low temperature smoldering conditions are in the vicinity of those cited for green vegetation and may not be resolved by present satellite platforms. Nevertheless, the experimental peak data set is of potential use for discriminating between a conflagration or accentuated fire and one characterized by smoldering at low temperature. SEM/ED analysis of the combusted leaf, branch, bark and various crown assemblages yields comparable morphological and geochemical signatures although potassium and light elements are slightly concentrated in effluent from the leafy matrix.

Padilla, D.; Steiner, J. C.

2005-12-01

164

Characterization of large amyloid fibers and tapes with Fourier transform infrared (FT-IR) and Raman spectroscopy.  

PubMed

Amyloids are self-assembled protein structures implicated in a host of neurodegenerative diseases. Organisms can also produce "functional amyloids" to perpetuate life, and these materials serve as models for robust biomaterials. Amyloids are typically studied using fluorescent dyes, Fourier transform infrared (FT-IR), or Raman spectroscopy analysis of the protein amide I region, and X-ray diffraction (XRD) because the self-assembled ?-sheet secondary structure of the amyloid can be easily identified with these techniques. Here, FT-IR and Raman spectroscopy analyses are described to characterize amyloid structures beyond just identification of the ?-sheet structure. It has been shown that peptide mixtures can self-assemble into nanometer-sized amyloid structures that then continue to self-assemble to the micrometer scale. The resulting structures are flat tapes of low rigidity or cylinders of high rigidity depending on the peptides in the mixture. By monitoring the aggregation of peptides in solution using FT-IR spectroscopy, it is possible to identify specific amino acids implicated in ?-sheet formation and higher order self-assembly. It is also possible to predict the final tape or cylinder morphology and gain insight into the structure's physical properties based on observed intermolecular interactions during the self-assembly process. Tapes and cylinders are shown to both have a similar core self-assembled ?-sheet structure. Soft tapes also have weak hydrophobic interactions between alanine, isoleucine, leucine, and valine that facilitate self-assembly. Rigid cylinders have similar hydrophobic interactions that facilitate self-assembly and also have extensive hydrogen bonding between glutamines. Raman spectroscopy performed on the dried tapes and fibers shows the persistence of these interactions. The spectroscopic analyses described could be generalized to other self-assembling amyloid systems to explain property and morphological differences. PMID:24359656

Ridgley, Devin M; Claunch, Elizabeth C; Barone, Justin R

2013-12-01

165

IMAGINED TRANSFORMATIONS 1 Running head: IMAGINED TRANSFORMATION OF BODIES  

E-print Network

IMAGINED TRANSFORMATIONS 1 Running head: IMAGINED TRANSFORMATION OF BODIES Imagined Transformations TRANSFORMATIONS 2 Abstract A number of spatial reasoning problems can be solved by performing an imagined transformation of one's egocentric perspective. A series of experiments were carried out to characterize

Zacks, Jeffrey M.

166

Natural Transformation in Mesophilic and Thermophilic Bacteria: Identification and Characterization of Novel, Closely Related Competence Genes in Acinetobacter sp. Strain BD413 and Thermus thermophilus HB27  

Microsoft Academic Search

The mesophile Acinetobacter sp. strain BD413 and the extreme thermophile Thermus thermophilus HB27 display high frequencies of natural transformation. In this study we identified and characterized a novel competence gene in Acinetobacter sp. strain BD413, comA, whose product displays significant similarities to the competence proteins ComA and ComEC in Neisseria and Bacillus species. Transcription of comA correlated with growth phase-dependent

ALEXANDRA FRIEDRICH; THOMAS HARTSCH; BEATE AVERHOFF

2001-01-01

167

In-Situ Synchrotron Characterization of Transformation Sequences in TiNi-Based Shape Memory Alloys during Thermal Cycling  

NASA Astrophysics Data System (ADS)

In-situ synchrotron radiation has been used to provide direct analysis of the transformation sequences in TiNi-based shape memory alloys during thermal cycling. The high resolution, narrow peak width Debye-Scherrer diffraction spectra enabled positive identification and quantification of the phase transformation sequences, which is not possible through normal laboratory studies. The results facilitate a clearer understanding of the development and influence of intermediate phases such as R or B19 on sequential martensitic transformations. Ti50.2Ni49.8 transformed predominately via a single-step B2 ? B19' transformation, although evidence of the R phase was found during cooling in every cycle. The martensitic start temperature was depressed by ~0.6 °C per cycle, while the R-phase start temperature was found to be unaffected. Ti50Ni41Cu9 transformed through a two-step B2 ? B19 ? B19' sequence, with the B2 ? B19 transformation reaching completion prior to the formation of any B19'. The transformation temperatures of Ti50Ni41Cu9 were found to be insensitive to thermal cycling, remaining constant over the studied cycle range.

Jones, N. G.; Raghunathan, S. L.; Dye, D.

2010-04-01

168

Characterization of Low Temperature Ferrite/Austenite Transformations in the Heat Affected Zone of 2205 Duplex Stainless Steel Arc Welds  

SciTech Connect

Spatially Resolved X-Ray Diffraction (SRXRD) has been used to identify a previously unobserved low temperature ferrite ({delta})/austenite({gamma}) phase transformation in the heat affected zone (HAZ) of 2205 Duplex Stainless Steel (DSS) welds. In this ''ferrite dip'' transformation, the ferrite transforms to austenite during heating to peak temperatures on the order of 750 C, and re-transforms to ferrite during cooling, resulting in a ferrite volume fraction equivalent to that in the base metal. Time Resolved X-Ray Diffraction (TRXRD) and laser dilatometry measurements during Gleeble{reg_sign} thermal simulations are performed in order to verify the existence of this low temperature phase transformation. Thermodynamic and kinetic models for phase transformations, including both local-equilibrium and para-equilibrium diffusion controlled growth, show that diffusion of substitutional alloying elements does not provide a reasonable explanation for the experimental observations. On the other hand, the diffusion of interstitial alloying elements may be rapid enough to explain this behavior. Based on both the experimental and modeling results, two mechanisms for the ''ferrite dip'' transformation, including the formation and decomposition of secondary austenite and an athermal martensitic-type transformation of ferrite to austenite, are considered.

Palmer, T A; Elmer, J W; Babu, S S; Vitek, J M

2003-08-20

169

Performance analysis of a plasmonic sensor based on gold nanoparticle film in infrared light using the admittance loci method  

NASA Astrophysics Data System (ADS)

A theoretical design of surface plasmon resonance (SPR) structure operating in attenuated total reflection (ATR) mode and comprising of silicon or chalcogenide (2S2G) prism material coated with gold film having different nanoparticle sizes has been reported along with some interesting performance related simulation results at the operating wavelength of 1200 nm in infrared. The admittance loci based technique has been employed for the appropriate choice of the metal layer thickness. The sensitivity and other performance parameters of the structure based on the choice of the high index prism material and correct gold nanoparticle size have also been presented. In comparison to other conventional prism based plasmonic structures, the proposed model provides the extra degree of freedom, i.e., variations of nanoparticle size in addition to the variation in layer thickness and the use of different high index prism materials like silicon, 2S2G materials, etc. Moreover, the width of the SPR curve can be controlled by using different high index prism materials as well as by changing gold nanoparticle size. Higher sensitivity can be achieved with 2S2G while higher detection accuracy is provided by silicon as prism material.

Brahmachari, Kaushik; Ray, Mina

2015-02-01

170

Characterization of the chemical composition of soil humic acids using Fourier transform ion cyclotron resonance mass spectrometry  

NASA Astrophysics Data System (ADS)

The composition of humic acids (HAs) with varying degrees of humification isolated from 10 common Japanese soils was characterized using negative ion mode electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry at 12 T. In particular, attention was paid to polynuclear aromatic components, which are more associated with the refractory nature of HAs and their resistance to biodegradation in soil than single C ring aromatic entities, such as lignin-like components, and aliphatic functionalities. Thousands of peaks were observed in the m/z range of 200-700, and molecular formulas were assigned to 817-2457 peaks in each sample. The molecular formulas having H/C and O/C ratios similar to those of lipid, protein, and other aliphatics with low double bond equivalents (DBE) of 0-7 were generally observed across the m/z range of 200-700. Although there were a number of molecular formulas having H/C and O/C values similar to those of lignin across the wide m/z range in the HAs with a low degree of humification, most lignin-like molecular formulas in the larger m/z range (450-650) or irrespective of m/z were lacking in the HAs with middle and high degrees of humification, respectively. These observations suggest a longer residence time for lignin monomers/dimers (and their derivatives; m/z 200-400) than larger lignin oligomers (m/z 450-650) in HA structural domains. The number of molecular formulas having H/C and O/C values similar to condensed aromatics increased with increasing degree of humification. The m/z and DBE values of condensed aromatic-like molecular formulas in the HAs with a lower degree of humification were <500 and 10-25, respectively, whilst the ranges expanded to 600 and 30-33, respectively, in the highly-humified black HAs. Kendrick mass defect analysis using a carboxyl group as the characteristic functional group found that 31, 73, and 39 molecular formulas had chain-type, net-type, and biphenyl-type condensed aromatic acids, respectively, as possible structures. Summed peak magnitudes of the condensed aromatic-like molecular formulas, in particular those with higher DBE values (>17) expected to have at least 5 rings, increased with increasing degree of humification and aromatic C content (evaluated by solid-state 13C nuclear magnetic resonance spectroscopy), suggesting their contribution to the intrinsic recalcitrance of HAs in soil.

Ikeya, Kosuke; Sleighter, Rachel L.; Hatcher, Patrick G.; Watanabe, Akira

2015-03-01

171

Identification and characterization of salmonella serotypes using DNA spectral characteristics by fourier transform infrared (FT-IR) spectroscopy  

Technology Transfer Automated Retrieval System (TEKTRAN)

Analysis of DNA samples of Salmonella serotypes (Salmonella Typhimurium, Salmonella Enteritidis, Salmonella Infantis, Salmonella Heidelberg and Salmonella Kentucky) were performed using Fourier transform infrared spectroscopy (FT-IR) spectrometer by placing directly in contact with a diamond attenua...

172

Characterization of Atomic Structure, Relaxation and Phase Transformation Mechanisms in Bulk and Thin Film Amorphous Chalcogenides and Gallium Antimonide  

NASA Astrophysics Data System (ADS)

This dissertation details the characterization of the atomic structure, relaxation processes and phase transformation mechanisms in a variety of chalcogenide (selenides and tellurides) and other non-oxide (Ga-Sb alloys) glasses which are highly relevant to optoelectronic and phase change memory applications. One of the principal goals of these studies is to develop a fundamental, atomistic understanding of the structure-property relationships in these materials. Variable temperature Raman spectroscopy is used to the study the structure and its temperature dependent relaxation in GexSe100-x glasses and supercooled liquids with x ? 33.33 %. It is shown that the compositional dependence of the relative fractions of the edge- and corner-shared GeSe4 tetrahedra is fully consistent with a structural model based on random connectivity between the tetrahedral and chain elements. Temperature-dependent structural changes involve a progressive conversion of edge-shared to corner shared GeSe4 tetrahedra with decreasing equilibration temperature. The time scale of this structural conversion agrees with both enthalpy and shear relaxation near the glass transition. The temperature dependent change in the edge- vs. corner- sharing tetrahedral speciation is shown to be related to the production of configurational entropy, indicating a connection between structural relaxation, configurational entropy, and viscous flow. A combination of Raman and 77Se nuclear magnetic resonance (NMR) spectroscopy is applied to study the structure of a series of Se-deficient GexSe100-x glasses, with 42 ? x ? 33.33. Considerable violation of chemical order in the nearest-neighbor coordination environments of the constituent atoms is observed in the stoichiometric GeSe2 glass. On the other hand, the presence of a random distribution of Ge-Ge bonds can be inferred in the Se-deficient glasses. Furthermore, the results of this study conclusively indicate that the structure of these glasses is intermediate between a randomly connected and a fully clustered network of GeSe4 tetrahedra and Se chains. Additionally, a new two-dimensional NMR spectroscopic technique is developed and applied to Ge-Se glasses that allowed the separation of isotropic and anisotropic chemical shifts. Through the analysis of the anisotropic sideband pattern in the second dimension it is possible to detect up to four distinct types of Se environments in the glass structure on the basis of their characteristic chemical shift anisotropies. 125Te NMR chemical shift systematics is established for coordination environments of Te atoms in a wide range of crystalline and glassy tellurides in the Ga-As-Sb-Te system. 125Te NMR spectroscopy is then used to investigate the short-range structure of amorphous and crystalline Ge1Sb2 Te4 and Ge2Sb2Te5 phase change alloys. Both alloys are found to consist of only heteropolar Ge/Sb-Te bonds in the amorphous and crystalline state and strong vacancy clustering in the nanocrystalline state that may facilitate a rapid displacive transformation between the amorphous and crystalline states without the need of significant atomic rearrangement or diffusion. Based on these 125Te NMR results a Te-centric model of the phase change mechanism in GST alloys is proposed. Structure and phase changes in amorphous Ga-Sb alloys are studied using synchrotron x-ray diffraction and 71Ga and 121Sb NMR spectroscopy. Pressure induced phase transformations in amorphous GaSb is shown to be consistent with the existence of an underlying polyamorphic phase transition between a low and a high-density amorphous phase. NMR results for amorphous Ga46Sb54 indicate that both Ga and Sb atoms are fourfold coordinated with 40% of these atoms participating in homopolar bonding in the as-deposited film. Subsequent crystallization into the zinc blend structure therefore requires extensive bond switching and elimination of homopolar bonds. For amorphous Ga14Sb86 both Ga and Sb atoms are found to be threefold coordinated allowing for a fast phase change kinetics although crystallization of thi

Edwards, Trenton Gerard

173

Natural Transformation in Mesophilic and Thermophilic Bacteria: Identification and Characterization of Novel, Closely Related Competence Genes in Acinetobacter sp. Strain BD413 and Thermus thermophilus HB27  

PubMed Central

The mesophile Acinetobacter sp. strain BD413 and the extreme thermophile Thermus thermophilus HB27 display high frequencies of natural transformation. In this study we identified and characterized a novel competence gene in Acinetobacter sp. strain BD413, comA, whose product displays significant similarities to the competence proteins ComA and ComEC in Neisseria and Bacillus species. Transcription of comA correlated with growth phase-dependent transcriptional regulation of the recently identified pilin-like factors of the transformation machinery. This finding strongly suggests that comA is part of a competence regulon. Examination of the genome sequence of T. thermophilus HB27 led to detection of a comA/comEC-like open reading frame (ORF) which is flanked by an ORF whose product shows significant similarities to the Bacillus subtilis competence protein ComEA. To examine whether these two ORFs, designated comEC and comEA, are implicated in natural transformation of T. thermophilus HB27, both were disrupted by using a thermostable kanamycin resistance marker. Natural transformation in comEC mutants was reduced 1,000-fold, whereas in comEA mutants the natural transformation phenotype was completely eliminated. These results strongly suggest that both genes, comEC and comEA, are required for natural transformation in T. thermophilus HB27. Several transmembrane ?-helices are predicted based on the amino acid sequences of ComA in Acinetobacter sp. strain BD413 and ComEC in T. thermophilus HB27, which suggests that ComA and ComEC are located in the inner membrane and function in DNA transport through the cytoplasmic membrane. PMID:11425734

Friedrich, Alexandra; Hartsch, Thomas; Averhoff, Beate

2001-01-01

174

Natural transformation in mesophilic and thermophilic bacteria: identification and characterization of novel, closely related competence genes in Acinetobacter sp. strain BD413 and Thermus thermophilus HB27.  

PubMed

The mesophile Acinetobacter sp. strain BD413 and the extreme thermophile Thermus thermophilus HB27 display high frequencies of natural transformation. In this study we identified and characterized a novel competence gene in Acinetobacter sp. strain BD413, comA, whose product displays significant similarities to the competence proteins ComA and ComEC in Neisseria and Bacillus species. Transcription of comA correlated with growth phase-dependent transcriptional regulation of the recently identified pilin-like factors of the transformation machinery. This finding strongly suggests that comA is part of a competence regulon. Examination of the genome sequence of T. thermophilus HB27 led to detection of a comA/comEC-like open reading frame (ORF) which is flanked by an ORF whose product shows significant similarities to the Bacillus subtilis competence protein ComEA. To examine whether these two ORFs, designated comEC and comEA, are implicated in natural transformation of T. thermophilus HB27, both were disrupted by using a thermostable kanamycin resistance marker. Natural transformation in comEC mutants was reduced 1,000-fold, whereas in comEA mutants the natural transformation phenotype was completely eliminated. These results strongly suggest that both genes, comEC and comEA, are required for natural transformation in T. thermophilus HB27. Several transmembrane alpha-helices are predicted based on the amino acid sequences of ComA in Acinetobacter sp. strain BD413 and ComEC in T. thermophilus HB27, which suggests that ComA and ComEC are located in the inner membrane and function in DNA transport through the cytoplasmic membrane. PMID:11425734

Friedrich, A; Hartsch, T; Averhoff, B

2001-07-01

175

Photolytic and photocatalytic transformation of methadone in aqueous solutions under solar irradiation: kinetics, characterization of major intermediate products and toxicity evaluation.  

PubMed

The present manuscript describes the transformation and mineralization of methadone (MET) in aqueous solutions (demineralized water (DW) and synthetic municipal wastewater effluent (SWeff)) by natural solar irradiation and two solar photocatalytic processes: heterogeneous photocatalysis with titanium dioxide (TiO2) and homogeneous photocatalysis by photo-Fenton. Direct solar irradiation resulted in almost complete transformation of MET in the investigated matrices after 20 h of normalized irradiation time. MET photocatalytic transformation required shorter illumination times in DW compared to SWeff. Only 16 and 36 min of solar illumination were required during photo-Fenton and photocatalysis with TiO2, respectively, to transform MET completely in SWeff. Mineralization of the dissolved organic carbon took place only during photocatalytic treatments. Kinetics parameters were calculated for processes comparison. Additionally, phototransformation intermediates generated during each treatment were investigated and characterized by means of ultra-performance liquid chromatography coupled to quadrupole-time of flight tandem mass spectrometry (UPLC-QqTOF-MS/MS). The main MET phototransformation pathways were observed to be hydroxylation, and fragmentation and cyclization. According to the Vibrio fischeri bioassay, the acute toxicity of the generated phototransformation products was not relevant, since the observed inhibition percentages of bacterial bioluminescence were always below 30% after 30 min of sample contact. PMID:21767861

Postigo, Cristina; Sirtori, Carla; Oller, Isabel; Malato, Sixto; Maldonado, Manuel Ignacio; López de Alda, Miren; Barceló, Damià

2011-10-15

176

Morphometric and biochemical characterization of red beet (Beta vulgaris L.) hairy roots obtained after single and double transformations.  

PubMed

It is known that T-DNA of Agrobacterium rhizogenes affects processes of plant development and activates the synthesis of secondary metabolites in transformed plant cells. In the present investigation, we provide evidence that different strains of A. rhizogenes significantly affect morphometric, morphological and functional characteristics of hairy roots of red beet (Beta vulgaris L.). Infection with four strains of A. rhizogenes (A4, A 2/83, A 20/83 and LMG-150) resulted in ten clones of hairy roots, which were named accordingly as A4(1), A4(2), A4(3), A 2/83(1), A 2/83(2), A 2/83(3), A 20/83(1), A 20/83(2), A 20/83(3) and LMG-150. Their growth characteristics, pigment content, levels of endogenous auxin and T-DNA copy number showed significant differences probably due to the physiological status of the host cell rather than the T-DNA copy number. Although A 2/83 showed highest hairy root induction capacity, the best hairy root clone was obtained with strain LMG-150 that produced highest biomass and pigments. In this root clone, the enzyme peroxidase was found involved in altering the endogenous auxin pool. When root clone LMG-150 was re-transformed to insert additional individual rol genes, two double transformed clones were obtained, one for rolABC and the other for rolC gene where the former produced higher biomass and betalaine than the latter. Despite the established fact that rol genes of T-DNA influence endogenous phytohormones, no direct correlation among the single transformants and the double transformants was found. This is the first report, in our knowledge, where a hairy root clone has been used to obtain double transformants. PMID:18327591

Thimmaraju, R; Venkatachalam, L; Bhagyalakshmi, N

2008-06-01

177

A systems level characterization and tradespace evaluation of a simulated airborne Fourier transform infrared spectrometer for gas detection  

NASA Astrophysics Data System (ADS)

The remote sensing gas detection problem is one with no straightforward solution. While success has been achieved in detecting and identifying gases released from industrial stacks and other large plumes, the fugitive gas detection problem is far more complex. Fugitive gas represents a far smaller target and may be generated by leaking pipes, vents, or small scale chemical production. The nature of fugitive gas emission is such that one has no foreknowledge of the location, quantity, or transient rate of the targeted effluent which requires one to cover a broad area with high sensitivity. In such a scenario, a mobile airborne platform would be a likely candidate. Further, the spectrometer used for gas detection should be capable of rapid scan rates to prevent spatial and spectral smearing, while maintaining high resolution to aid in species identification. Often, insufficient signal to noise (SNR) prevents spectrometers from delivering useful results under such conditions. While common dispersive element spectrometers (DES) suffer from decreasing SNR with increasing spectral dispersion, Fourier Transform Spectrometers (FTS) generally do not and would seemingly be an ideal choice for such an application. FTS are ubiquitous in chemical laboratories and in use as ground based spectrometers, but have not become as pervasive in mobile applications. While FTS spectrometers would otherwise be ideal for high resolution rapid scanning in search of gaseous effluents, when conducted via a mobile platform the process of optical interferogram formation to form spectra is corrupted when the input signal is temporally unstable. This work seeks to explore the tradespace of an airborne Michelson based FTS in terms of modeling and characterizing the performance degradation over a variety of environmental and optical parameters. The major variables modeled and examined include: maximum optical path distance (resolution), scan rate, platform velocity, altitude, atmospheric and background emissivity variability, gas target parameters such as temperature, concentration-pathlength, confuser gas presence, and optical effects including apodization effects, single and double-sided interferograms, internal mirror positional accuracy errors, and primary mirror jitter effects. It is through an understanding of how each of the aforementioned variables impacts the gas detection performance that one can constrain design parameters in developing and engineering an FTS suitable to the airborne environment. The instrument model was compared to output from ground-based FTS instruments as well as airborne data taken from the Airborne Hyperspectral Imager (AHI) and found to be in good agreement. Monte Carlo studies were used to map the impact of the performance variables and unique detection algorithms, based on common detection scores, were used to quantify performance degradation. Scene-based scenarios were employed to evaluate performance of a scanning FTS under variable and complex conditions. It was found that despite critical sampling errors and rapidly varying radiance signals, while losing the ability to reproduce a radiometrically accurate spectrum, an FTS offered the unique ability to reproduce spectral evidence of a gas in scenarios where a dispersive element spectrometer (DES) might not.

Weiner, Aaron

178

Hydration and energy dissipation measurements of biomolecules on a piezoelectric quartz oscillator by admittance analyses.  

PubMed

By using a 27-MHz piezoelectric quartz oscillator connected with a vector network analyzer, we obtained resonance frequency decreases (-DeltaFwater) and energy dissipation increases (DeltaDwater) during binding of biotinylated bovine serum albumin, biotinylated ssDNA, biotinylated dsDNA, and biotinylated pullulan to a NeutrAvidin-immobilized 27-MHz quartz crystal microbalance (QCM) plate in aqueous solution, as well as in the wet air phase (98% humidity, -DeltaFwet and DeltaDwet) and in the dry air phase (-DeltaFair and DeltaDair). -DeltaFwater indicates the total mass of the molecule, bound water, and vibrated water in aqueous solutions. -DeltaFwet indicates the total mass of the molecule and bound water. -DeltaFair simply shows the real mass of the molecule on the QCM. In terms of results, (-DeltaFwet)/(-DeltaFair) values indicated the bound water ratios per unit biomolecular mass were on the order of pullulan (2.1-2.2) > DNAs = proteins (1.4-1.6) > polystyrene (1.0). The (-DeltaFwater)/(-DeltaFair) values indicated the hydrodynamic water (bound and vibrated water) ratios per unit biomolecular mass were on the order of dsDNA (6.5) > ssDNA = pullulan (3.5-4.4) > proteins (2.4-2.5) > polystyrene (1.0). Energy dissipation parameters per unit mass in water (DeltaDwater/(-DeltaFair)) were on the order of pullulan > dsDNA > ssDNA > proteins > polystyrene. Energy dissipation in the wet and dry air phases (DeltaDwet and DeltaDair) were negligibly small, which indicates even these biomolecules act as elastic membranes in the air phase (without aqueous solution). We obtained a good linear relationship between [(-DeltaFwater)/(-DeltaFair) - 1], which is indicative of hydration and DeltaDwater/(-DeltaFair) of proteins. The aforementioned values suggest that the energy dissipation of proteins was mainly caused by hydration and that proteins themselves are elastic molecules without energy dissipation in aqueous solutions. On the contrary, plots in cases of denatured proteins, DNAs, and pullulans were relatively deviant toward the large hydration and energy dissipation from the theoretical line as perfect elastic materials, meaning that the large energy dissipation occurs because of viscoelastic properties of denatured proteins, linear DNAs, and pullulans in the water phase, in addition to energy dissipation due to the hydration of molecules. These two parameters could characterize various biomolecules with structural properties in aqueous solutions. PMID:17194124

Ozeki, Tomomitsu; Morita, Mizuki; Yoshimine, Hiroshi; Furusawa, Hiroyuki; Okahata, Yoshio

2007-01-01

179

The characterization of coatings utilizing thermal extraction/gas chromatography followed by Fourier transform infrared spectroscopy and/or mass spectrometry  

SciTech Connect

The characterization of coatings utilizing thermal extraction/gas chromatography followed by fourier transform infrared spectroscopy and/or mass spectrometry is a very powerful hyphenated technique capable of providing definitive answers to questions of QA/QC during the development of a paint formulation, during its manufacture, during its application, or during its investigation after a coating failure. Small recovered paint chips reveal a portion of their past history. Positive identification of generic binder types, solvent entrapment, unreacted monomer, and improper catalyzation are demonstrated. Plastic type and degree of degradation may be identified. An introduction to the versatility of the instrument is presented.

Mills, G. [George Mills and Associates International, Inc., Humble, TX (United States); Bell, B.; Shirey, E.L. [Bell Evaluation Lab., Houston, TX (United States)

1994-12-31

180

Characterization of epitaxial transformation phenomena induced by the interaction of implanted N-ions with Ti thin films  

NASA Astrophysics Data System (ADS)

In order to clarify correlations between implanted N-ions, and Ti sublattices and its ligand atoms (H atoms in TiHx) in the early N-implantation stage, nitriding processes of Ti thin films during N-implantation were investigated by in situ observations of TEM and EELS, with the aid of DV-X? calculations. Nitriding of TiHx in the deposited Ti films by N-occupations of octahedral sites of H-released fcc-Ti sublattices leads to the formation of TiNy without transformation of Ti sublattices. On the other hand, the shift of the atoms on the closed-packed (00·1) plane of hcp-Ti induced by the bonding interaction of Ti sublattices with implanted N atoms plays an important role in the epitaxial transformation of hcp-Ti to fcc-Ti sublattices due to the occupation by N atoms, partially inheriting the specific atomic arrangements of hcp-Ti. Moreover, it has been found from the analyses of EELS measurements that the hcp-fcc transformation occurs preferentially above a critical concentration ratio, N/Ti ? 0.25. This means that above the N/Ti ? 0.25, the invasion of an implanted N atom to the N-unoccupied octahedral site in the neighboring unit cell next to the N-occupied one in hcp-Ti occurs preferentially, and induces the growth of nucleus of the hcp-fcc transformation.

Kasukabe, Yoshitaka; Shimoda, Hiroyuki; Chen, Yu; Yamamoto, Shunya; Yoshikawa, Masahito; Fujino, Yutaka

2013-11-01

181

Diffuse-Reflectance Fourier-Transform Mid-Infrared Spectroscopy as a Method of Characterizing Changes in Soil Organic Matter  

Technology Transfer Automated Retrieval System (TEKTRAN)

Diffuse-Reflectance Fourier-Transform Mid-Infrared Spectroscopy (FTIR) can be used quickly and non destructively to identify and quantify the presence of important organic functional groups in environmental samples. However, soils contain myriad organic and inorganic components that absorb in the M...

182

CHARACTERIZATION OF AMBIENT PM2.5 AEROSOL AT A SOUTHEASTERN US SITE: FOURIER TRANSFORM INFRARED ANALYSIS OR PARTICLE PHASE  

EPA Science Inventory

During a field study in the summer of 2000 in the Research Triangle Park (RTP), aerosol samples were collected using a five stage cascade impactor and subsequently analyzed using Fourier Transform Infrared Spectroscopy (FTIR). The impaction surfaces were stainless steel disks....

183

Étude par spectroscopie d'admittance et MEB de la dégradation électrique des couches minces de CuAlS{2} non dopé déposées sous vide  

NASA Astrophysics Data System (ADS)

We have accelerated the ageing of CuAlS2 by the application of a static electrical field for different degradation times. We have investigated the admittance spectroscopy and the scanning electron microscopy to follow and understand the (mass-charge) coupled transport processes produced in the volume and on the surface of these films. The electrical constraint induces, after an incubation phase, an activated decrease of the resistance, followed by a susbstantial increase correlated to the formation of an open circuit. This degradation occurs more rapidly for the films having initially a lower resistance, due to the thermal dissipation which increases considerably the temperature to about 140 °C. Admittance spectra reveal, at low frequencies, a capacitive loop related to the formation of a charge space induced by copper diffusion. Such migration develop induces the formation of copper arborescences, spreading from the cathode towards the anode. The effect of these structures on the properties of the degraded films is discussed in relation to electromigration and associated processes (whiskers, fracture, healing, bridge-building, ...). Also, we have noticed their similarity with fractal phenomena such as electrodeposition and dielectric breakdown. Nous avons accéléré le vieillissement des couches minces de CuAlS2 par l'application d'un champ électrique statique pendant des durées variables. Nous avons fait appel à la spectroscopie d'admittance et la microscopie électronique à balayage, pour suivre et comprendre les processus de transport couplé (masse- charge) qui se produisent en volume et en surface de ces couches. L'effet de la contrainte électrique s'est traduit, après une phase d'incubation, par une décroissance activée de la résistance, suivie d'une phase d'emballement reliée à la formation d'un circuit ouvert. Cette fracturation se manifeste plus rapidement pour les couches ayant initialement une faible résistance, suite à l'effet de la dissipation thermique qui peut augmenter notablement leur température (140 °C). Les spectres d'admittance révèlent, vers les basses fréquences, une boucle capacitive reliée à la formation d'une charge d'espace induite par la diffusion du cuivre. Une telle migration développe, sur la surface depuis la cathode, des arborescences de cuivre orientées vers l'anode. L'effet de ces structures sur les propriétés des couches dégradées a été discuté en mettant en cause le phénomène d'électromigration et ses mécanismes associés (whiskers, fracture, “healing", pontage, ...). De même, nous avons noté leur similarité avec des phénomènes fractals tels que l'électrodéposition ou le claquage diélectrique.

Helali, N.; Bouricha, B.; Rezig, B.

1998-07-01

184

Functional biocompatible magnetite-cellulose nanocomposite fibrous networks: Characterization by fourier transformed infrared spectroscopy, X-ray powder diffraction and field emission scanning electron microscopy analysis  

NASA Astrophysics Data System (ADS)

The preparation and characterization of functional biocompatible magnetite-cellulose nano-composite fibrous material is described. Magnetite-cellulose nano-composite was prepared by a combination of the solution-based formation of magnetic nano-particles and subsequent coating with amino celluloses. Characterization was accomplished using X-ray powder diffraction (XRD), fourier transformed infrared (FTIR) and field emission scanning electron microscopy (FESEM) analysis. The peaks of Fe3O4 in the XRD pattern of nanocomposite confirm existence of the nanoparticles in the amino cellulose matrix. Magnetite-cellulose particles exhibit an average diameter of roughly 33 nm as demonstrated by field emission scanning electron microscopy. Magnetite nanoparticles were irregular spheres dispersed in the cellulose matrix. The vibration corresponding to the Nsbnd CH3 functional group about 2850 cm-1 is assigned in the FTIR spectra. Functionalized magnetite-cellulose nano-composite polymers have a potential range of application as targeted drug delivery system in biomedical field.

Habibi, Neda

2015-02-01

185

Evidences of buried loads in the base of the crust of Borborema Plateau (NE Brazil) from Bouguer admittance estimates  

NASA Astrophysics Data System (ADS)

In the Borborema Province (BP) - northeastern Brazil - two important Cenozoic events occurred at the surface: the Macau magmatism and the Borborema Plateau epeirogenesis. To obtain appropriated-scale geophysical data to explain the deep origins of these two events, different gravimetric/elevation databases were integrated with new surveys. Bouguer admittance estimates reveal that isostatic condition of the BP, especially in the Borborema Plateau, can be explained using elastic models to the lithosphere only if surface and buried loadings are combined. If the buried load is applied in the base of the crust, the ratio between buried and surface weights is circa 15 for a lithosphere with effective elastic thickness around 15 km and crust thickness around 33 km. From an interpretative viewpoint of the buried load, it is assumed that the lower crust under the Borborema Plateau might have an anomalous high value of density. Magmatic underplating might explain this fact as well as the observed surface magmatism and epeirogenesis. Crustal thickening of about 4 km under the Borborema Plateau and intracrustal seismic velocity discontinuity with high Vp/Vs ratio are geophysical facts consistent with magmatic underplating. However, the surface magmatism presents low volume and mainly alkaline composition - facts that are not entirely consistent with the hypothesis of magmatic underplating. Regardless the validity of this hypothesis, Cenozoic-to-present events in BP might be somewhat associated with imbalances in lithosphere-asthenospheric mantle and/or crust-lithospheric mantle systems. The existence of free-air anomalies showing no null integral over area and of an expressive positive geoid anomaly are geophysical evidences of these imbalances. Possibly, the Borborema Plateau is still suffering epeirogenesis. Post-depositional deformation found in Barreiras Formation strata, Late Quaternay fault reactivations, and AFT thermochronology analysis suggesting the existence of a cooling stage between 20 and 0 Ma might be geologic evidences of the continued action of epeirogenesis until the present. In addition, the relatively high level of the present intraplate seismicity recorded in several regions of the BP is another unequivocal geophysical evidence that the crust of the province is still submitted to accommodation processes.

de Oliveira, Roberto Gusmão; de Medeiros, Walter Eugênio

2012-08-01

186

Characterization of Naturally Occurring Surface and Interface-Active Molecules in Petrochemicals by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry  

Microsoft Academic Search

High-resolution electrospray ionization Fourier Transform Ion Cyclotron Mass Spectrometry (ESI FT-ICR MS) is a robust method for identifying polar nitrogen, sulfur, and oxygen (–NSO) containing compounds in naturally occurring complex mixtures (i.e. coal, humic acids, crude oil, etc…) as it affords an average mass resolution m\\/?m50% ?100, 000 and mass accuracy <0.3 ppm. In Chapter 3, we apply ESI FT-ICR

Lateefah Ain Stanford

2006-01-01

187

Characterization of transformer coupled oxygen plasmas by trace rare gases-optical emission spectroscopy and Langmuir probe analysis  

Microsoft Academic Search

Trace rare gases-optical emission spectroscopy (TRG-OES) and Langmuir probe analysis have been used to measure the electron temperature, Te , in a high-density inductively (transformer) coupled (TCP) 10 mTorr oxygen plasma as a function of the 13.56 MHz radio frequency (rf) power. The oxygen atomic densities were estimated by O-atom optical emission (8446 Å), and rare gas actinometry (Ar, 7504

N. C. M. Fuller; M. V. Malyshev; V. M. Donnelly; Irving P. Herman

2000-01-01

188

ICAM-1 Expression in a Spontaneously Transformed Human Keratinocyte Cell Line: Characterization by a Simple Cell-ELISA Assay  

Microsoft Academic Search

Interferon gamma (IFN-?) is known to induce ICAM-1 on keratinocytes (KC) in vitro, and its expression in vivo is correlated with epidermal T-cell infiltration in various dermatoses. However, the mechanisms for this cytokine-mediated ICAM-1 expression are essentially unknown. We investigated the induction of ICAM-1 by IFN-? in HaCaT cells, a spontaneously transformed human KC cell line, using an immunoperoxidase-ELISA with

Anthony P. Winiski; Carolyn A. Foster

1992-01-01

189

Structure characterization of petroleum vacuum residues by in-beam EI Fourier transform ion cyclotron resonance mass spectrometry  

Microsoft Academic Search

A n-heptane soluble fraction (AH-VR-Sa) of Arabian heavy vacuum residues (AH-VR) has been analyzed by in-beam electron ionization Fourier transform ion cyclotron resonance mass spectrometry (EI FT-ICR MS). The probe temperature and the ionization energy of in-beam EI were independently adjusted to expand the detectable range of peaks originating from components of AH-VR-Sa and to prevent fragmentation of the molecular

Keiko Miyabayashi; Yasuhide Naito; Kazuo Tsujimoto; Mikio Miyake

2002-01-01

190

Characterization of the ?-1,3-glucanase gene in peanut (Arachis hypogaea L.) by cloning and genetic transformation.  

PubMed

Plant ?-1,3-glucanases are commonly involved in disease resistance. This report describes the cloning and genetic transformation of a ?-1,3-glucanase gene from peanut. The gene was isolated from both the genomic DNA and cDNA of peanut variety Huayu20 by polymerase chain reaction (PCR) and reverse transcription PCR (RT-PCR), respectively. The DNA sequence contained 1471 bp including two exons and one intron, and the coding sequence contained 1047 bp that coded for a 348-amino acid protein with a calculated molecular weight of 38.8 kDa. The sequence was registered in NCBI (GenBank accession No. JQ801335) and was designated as Ah-Glu. As determined by BLAST analysis, the Ah-Glu protein has 42-90% homology with proteins from Oryza sativa (BAC83070.1), Zea mays (NP_001149308), Arabidopsis thaliana (NP_200470.1), Medicago sativa (ABD91577.1), and Glycine max (XP_003530515.1). The over-expression vector pCAMBIA1301-Glu containing Ah-Glu was constructed, confirmed by PCR and restriction enzyme digestion, and transformed into peanut variety Huayu22 by Agrobacterium EHA105-mediated transformation. The putative transformed plants (T0) were confirmed by PCR amplification. RT-PCR analysis and ?-glucuronidase (GUS) staining showed that the transferred Ah-Glu was expressed as mRNA and protein. In a laboratory test, the transgenic plants were found to be more resistant to the fungal pathogen Cercospora personata than the non-transgenic plants were. PMID:24668677

Qiao, L X; Ding, X; Wang, H C; Sui, J M; Wang, J-S

2014-01-01

191

Characterization of separability and entanglement in $(2\\times{D})$- and $(3\\times{D})$-dimensional systems by single-qubit and single-qutrit unitary transformations  

E-print Network

We investigate the geometric characterization of pure state bipartite entanglement of $(2\\times{D})$- and $(3\\times{D})$-dimensional composite quantum systems. To this aim, we analyze the relationship between states and their images under the action of particular classes of local unitary operations. We find that invariance of states under the action of single-qubit and single-qutrit transformations is a necessary and sufficient condition for separability. We demonstrate that in the $(2\\times{D})$-dimensional case the von Neumann entropy of entanglement is a monotonic function of the minimum squared Euclidean distance between states and their images over the set of single qubit unitary transformations. Moreover, both in the $(2\\times{D})$- and in the $(3\\times{D})$-dimensional cases the minimum squared Euclidean distance exactly coincides with the linear entropy (and thus as well with the tangle measure of entanglement in the $(2\\times{D})$-dimensional case). These results provide a geometric characterization of entanglement measures originally established in informational frameworks. Consequences and applications of the formalism to quantum critical phenomena in spin systems are discussed.

Salvatore M. Giampaolo; Fabrizio Illuminati

2007-08-03

192

Characterization of separability and entanglement in (2xD)- and (3xD)-dimensional systems by single-qubit and single-qutrit unitary transformations  

SciTech Connect

We investigate the geometric characterization of pure state bipartite entanglement of (2xD)- and (3xD)-dimensional composite quantum systems. To this aim, we analyze the relationship between states and their images under the action of particular classes of local unitary operations. We find that invariance of states under the action of single-qubit and single-qutrit transformations is a necessary and sufficient condition for separability. We demonstrate that in the (2xD)-dimensional case the von Neumann entropy of entanglement is a monotonic function of the minimum squared Euclidean distance between states and their images over the set of single qubit unitary transformations. Moreover, both in the (2xD)- and in the (3xD)-dimensional cases the minimum squared Euclidean distance exactly coincides with the linear entropy [and thus as well with the tangle measure of entanglement in the (2xD)-dimensional case]. These results provide a geometric characterization of entanglement measures originally established in informational frameworks. Consequences and applications of the formalism to quantum critical phenomena in spin systems are discussed.

Giampaolo, Salvatore M. [Dipartimento di Matematica e Informatica, Universita degli Studi di Salerno, Via Ponte don Melillo, I-84084 Fisciano (Italy); CNR-INFM Coherentia, Naples (Italy); CNISM Unita di Salerno and INFN Sezione di Napoli, Gruppo collegato di Salerno, Baronissi (Italy); Illuminati, Fabrizio [Dipartimento di Matematica e Informatica, Universita degli Studi di Salerno, Via Ponte don Melillo, I-84084 Fisciano (Italy) and CNR-INFM Coherentia, Naples (Italy); CNISM Unita di Salerno and INFN Sezione di Napoli, Gruppo collegato di Salerno, Baronissi (Italy); ISI Foundation for Scientific Interchange, Villa Gualino, Viale Settimio Severo 65, I-10133 Turin (Italy)

2007-10-15

193

Characterization of metoprolol biodegradation and its transformation products generated in activated sludge batch experiments and in full scale WWTPs.  

PubMed

Metoprolol (MTP) is a compound of concern, considered as an emerging contaminant due to its high consumption, pseudopersistence and potential ecotoxicity. Activated sludge batch experiments were performed to evaluate the biological transformation of MTP and the formation of transformation products under different treatment conditions. Total MTP removal was obtained in aerobic conditions, and the formation of MTP known metabolites (metoprolol acid (MTPA), ?-hydroxymetoprolol (?-HMTP) and O-desmethylmetoprolol (O-DMTP)) and unknown transformation products (TPs) was investigated. The three known metabolites and two new TPs generated along the experiments were identified by liquid chromatography coupled to high resolution mass spectrometry. For the two new TPs plausible structures were proposed based on the tentative identification. MTPA had the major ratio formation for the TPs identified along the experiments (up to 40% of initial MTP concentration after 96 h treatment) and its persistence through biological treatment was proven. Ecotoxicity studies using Vibrio fischeri bioluminescent bacteria in an acute toxicity test showed that MTP and its known TPs are not toxic with the exception of o-DMTP. Finally, MTP and its TPs were monitored in a full scale membrane bioreactor and in a full scale conventional urban wastewater treatment plant (WWTP) and the results were compared with those obtained in batch experiments. ?-HMTP was detected for the first time in a WWTP influent whereas MTPA was detected in influent and effluent WWTP samples at much higher levels (up to 100 folds higher) than MTP itself remarking its high persistence. PMID:24973729

Rubirola, A; Llorca, M; Rodriguez-Mozaz, S; Casas, N; Rodriguez-Roda, I; Barceló, D; Buttiglieri, G

2014-10-15

194

In vitro Tn7 mutagenesis of Haemophilus influenzae Rd and characterization of the role of atpA in transformation.  

PubMed Central

Haemophilus influenzae Rd is a gram-negative bacterium capable of natural DNA transformation. The competent state occurs naturally in late exponential growth or can be induced by a nutritional downshift or by transient anaerobiosis. The genes cya, crp, topA, and sxy (tfoX) are known to function in the regulation of competence development. The phosphoenolpyruvate:carbohydrate phosphotransferase system functions to maintain levels of cyclic AMP necessary for competence development but is not directly involved in regulation. The exact signal(s) for competence and the genes that mediate the signal(s) are still unknown. In an effort to find additional regulatory genes, H. influenzae Rd was mutated by using an in vitro Tn7 system and screened for mutants with a reduced ability to induce the competence-regulatory gene, comA. Insertions in atpA, a gene coding for the alpha subunit of the F1 cytoplasmic domain of the ATP synthase, reduce transformation frequencies about 20-fold and cause a significant reduction in expression of competence-regulatory genes, while the expression of constitutive competence genes is only minimally affected. In addition, we found that an insertion in atpB, which encodes the a subunit of the F0 membrane-spanning domain, has a similar effect on transformation frequencies. PMID:9393695

Gwinn, M L; Stellwagen, A E; Craig, N L; Tomb, J F; Smith, H O

1997-01-01

195

Preparation, Characterization and Microelectronic Applications of Langmuir Blodgett Films.  

NASA Astrophysics Data System (ADS)

This thesis evaluates the use of ultrathin Langmuir Blodgett (LB) films in semiconductor technology. Three different applications are explored: electron-beam resists, dielectric films, and tunneling dimension insulators. Deposition processes are established for LB films of cadmium brassidate, and Poly-Methyl-Methacrylate (PMMA). Film are characterized on the water subphase of the LB trough with a Wilhelmy balance and on various substrates with X-ray diffraction, Grazing Incidence Reflection Fourier Transform Infrared Spectroscopy (GIR FTIR), Scanning Electron Microscopy (SEM), Ellipsometry, Scanning Tunnelling Microscopy (STM) and electrical conduction and admittance measurements. Ultrathin PMMA LB films are shown to behave as excellent e-beam resists. PMMA LB films 10.5nm thick (13 monolayers) have pinhole densities (10/cm^2 ) three orders of magnitude smaller than those spin cast films of the same thickness. Furthermore, the same PMMA LB film thickness is able to protect a 50nm Cr underlayer for well over 13 minutes from chemical etchants. Low energy e-beam exposure of ultrathin PMMA LB films was demonstrated with the STM. The advantages of the STM as a lithography tool is that small diameter (<50nm) low energy (20eV to 100eV) e-beams may be used with LB resist films to obtain submicron resolution and reduced proximity effects due to less scattering of electrons within the ultrathin LB resist. Electrical conduction and admittance of metal/insulator/metal capacitors are studied for various thickness LB PMMA films, and electrode materials. Capacitors with Au electrodes were shorted due to pinholes in the LB film. Shorts were not observed with Al electrodes as a result of the native alumina. The thickness and dielectric constant of PMMA monolayers and Al_2O_3 are obtained. Diverse conduction mechanisms are proposed for Al electrode capacitors separated by no PMMA film; one monolayer; and three or more monolayers. Electrical properties of Au/PMMA/n-Si diodes with various thickness LB PMMA films was investigated. Inversion of the Si surface was not possible due to leakage of minority carriers through pinholes in the PMMA. MIS diodes incorporating LB PMMA films thinner than 4nm were shown to perform as solar cells with a larger open circuit voltage and efficiency compared to MS diodes.

Maccagno, Pierre Luigi

196

Admittance fluctuations in nanostructures  

NASA Astrophysics Data System (ADS)

In this thesis, we develop a first principle technique to study linear AC and the nonlinear DC quantum transport in diffusive conductors. Starting from Buttiker's theory for AC and DC transport, the emittance and nonlinear DC conductance are found in terms of the scattering matrix and it's functional derivative. New theoretical tools are developed to compute the functional derivative of the scattering matrix, which would otherwise be unaccessible. These results allows us to compute the linear AC and the nonlinear DC conductance for a diffusive conductor from first principles, for the first time in literature. The sample-to-sample AC conductance fluctuations are computed for a diffusive conductor. In this regime the dynamic response of the conductor can either be capacitive or inductive, depending on impurity configuration. Our results also suggest a crossover for the AC conductance distribution, from a symmetric to a non symmetric distribution function as the number of impurities increases. A degree of generic behavior is discovered, in that the AC fluctuation amplitudes become independent of the strength of the impurities, although it depends on the impurity density. A sample-to-sample analysis of the nonlinear conductance fluctuations, in the diffusive regime, is also reported. In this situation the distribution function is found to be a symmetric Gaussian like function for small disorder and a symmetric exponentially decaying function for large disorder. An interesting result is that the conductance fluctuations increase in an exponential fashion with N, the number of impurities. We also considered in this thesis the magneto-conductance fluctuations of a quasi-1D quantum wire with artificial impurities (antidots). This problem can only be solved numerically because of the finite size of the artificial impurities. We develop a novel transfer matrix technique to solve the quantum scattering problem by computing the scattering wave function, as a function of the external magnetic field. The Landauer-Buttiker equation is used to compute the magneto-conductance. This work is motivated by the experimental study [1], where several conductance fluctuations anomalies were reported. Our numerical results give good quantitative agreement with the experimental data and confirms the physical picture obtained from the experiment.

de Jesus, Tiago

197

Learning reactive admittance control  

Microsoft Academic Search

A peg-in-hole insertion task is used as an example to illustrate the utility of direct associative reinforcement learning methods for learning control under real-world conditions of uncertainty and noise. An associative reinforcement learning system has to learn appropriate actions in various situations through a search guided by evaluative performance feedback The authors used such a learning system, implemented as a

Vijaykumar Gullapalli; Roderic A. Grupen; Andrew G. Barto

1992-01-01

198

Resin characterization in cured graphite fiber reinforced composites using diffuse reflectance-FTIR. [Fourier transform infrared spectroscopy  

NASA Technical Reports Server (NTRS)

The feasibility of using diffuse reflectance in combination with Fourier transform infrared spectroscopy to obtain information on cured graphite fiber reinforced polymeric matrix resin composites was investigated. Several graphite/epoxy, polysulfone, and polyimide composites exposed to thermal or radiation environments were examined. An experimental polyimide-sulfone adhesive tape was also studied during processing. In each case, significant changes in resin molecular structure was observed due to environmental exposure. These changes in molecular structure were correlated with previously observed changes in material properties providing new insights into material behavior.

Young, P. R.; Stein, B. A.; Chang, A. C.

1983-01-01

199

EBSD characterization of high-temperature phase transformations in an Al-Si coating on Cr-Mo steel  

SciTech Connect

5Cr-0.5Mo steel was coated by hot-dipping in a molten bath containing Al-10 wt.% Si. The phase transformation in the aluminide layer during diffusion at 750 Degree-Sign C in static air was analyzed by electron backscatter diffraction. The results show the aluminide layer of the as-coated specimen consisted of an outer Al-Si topcoat, a middle layer formed of scattered {tau}{sub 5(C)}-Al{sub 7}(Fe,Cr){sub 2}Si particles and minor plate-shaped {tau}{sub 4}-Al{sub 4}FeSi{sub 2} and {tau}{sub 6}-Al{sub 4}FeSi phases in the Al-Si matrix and an inner continuous {tau}{sub 5(H)}-Al{sub 7}Fe{sub 2}Si layer, respectively from the coating surface to the steel substrate. The formation of FeAl{sub 3} and Fe{sub 2}Al{sub 5} with {tau}{sub 1}-(Al,Si){sub 5}Fe{sub 3} precipitates can be observed with increasing exposure time at 750 Degree-Sign C. After 5 h of exposure, the Al-Si topcoat has been consumed, and the aluminide layer consisted of Fe{sub 2}Al{sub 5} and a few {tau}{sub 1}-(Al,Si){sub 5}Fe{sub 3} precipitates. The FeAl phase not only formed at the interface between Fe{sub 2}Al{sub 5} and the steel substrate, but also transformed from {tau}{sub 1}-(Al,Si){sub 5}Fe{sub 3} after diffusion for 10 h. With prolonged exposure, the aluminide layer comprised only FeAl{sub 2} and FeAl. - Highlights: Black-Right-Pointing-Pointer EBSD can differentiate phases in aluminide layer with similar chemical compositions. Black-Right-Pointing-Pointer Mapping and EBSPs functions in EBSD provide a reliable phase identification. Black-Right-Pointing-Pointer A phase transformation in the aluminide layer has been described in detail. Black-Right-Pointing-Pointer 5 Fe-Al-Si and 4 Fe-Al intermetallic phases are performed during the diffusion. Black-Right-Pointing-Pointer Cubic {tau}{sub 5(C)}-Al{sub 7} (Fe,Cr){sub 2}Si and hexagonal {tau}{sub 5(H)}-Al{sub 7}(Fe,Cr){sub 2}Si are identified.

Cheng, Wei-Jen, E-mail: d9603505@mail.ntust.edu.tw; Wang, Chaur-Jeng

2012-02-15

200

Isolation and characterization of human prorenin secreted from murine cells transformed with a bovine papillomavirus-preprorenin expression vector  

SciTech Connect

The authors report the construction of a plasmid-based expression vector that carries the murine metallothionein gene promoter, the human preprorenin gene, the Tn5 phosphotransferase gene, and a complete bovine papilloma virus genome. Murine cells transformed with this vector constitutively secrete high levels of human prorenin as determined by immunoprecipitation of culture media with anti-human renin antibody and activity assays. An immunoaffinity system for the isolation of human prorenin from serum-free media, or media containing serum, was developed. Purified human prorenin is stable for months and is fully activated to enzymatically mature renin by limited tryptic digestion. This is the first example of a recombinant system leading to the isolation of research quantities of highly pure and fully activatable human prorenin.

Evans, D.B.; Weighous, T.F.; Cornette, J.C.; Tarpley, W.G.; Sharma, S.K.

1987-07-01

201

Thermal behavior of silicone rubber-based ceramizable composites characterized by Fourier transform infrared (FT-IR) spectroscopy and microcalorimetry.  

PubMed

Ceramizable (ceramifiable) silicone rubber-based composites are commonly used for cable insulation. These materials are able to create a protective ceramic layer during fire due to the ceramization process, which occurs at high temperature. When the temperature is increased, the polymer matrix is degraded and filler particles stick together by the fluxing agent, producing a solid, continuous ceramic phase that protects the copper wire from heat and mechanical stress. Despite increasing interest in these materials that has resulted in growing applications in the cable industry, their thermal behavior and ceramization process are still insufficiently described in the literature. In this paper, the thermal behavior of ceramizable silicone rubber-based composites is studied using microcalorimetry and Fourier transform infrared spectroscopy. The analysis of the experimental data made it possible to develop complete information on the mechanism of composite ceramization. PMID:24359658

Anyszka, Rafa?; Bieli?ski, Dariusz M; J?drzejczyk, Marcin

2013-12-01

202

Characterization of plasmonic hole arrays as transparent electrical contacts for organic photovoltaics using high-brightness Fourier transform methods  

PubMed Central

We present a methodology for probing light-matter interactions in prototype photovoltaic devices consisting of an organic semiconductor active layer with a semitransparent metal electrical contact exhibiting surface plasmon-based enhanced optical transmission. We achieve high-spectral irradiance in a spot size of less than 100??m using a high-brightness laser-driven light source and appropriate coupling optics. Spatially resolved Fourier transform photocurrent spectroscopy in the visible and near-infrared spectral regions allows us to measure external quantum efficiency with high sensitivity in small-area devices (<1?mm2). This allows for rapid fabrication of variable-pitch sub-wavelength hole arrays in metal films for use as transparent electrical contacts, and evaluation of the evanescent and propagating mode coupling to resonances in the active layer. PMID:25705085

Camino, Fernando E.; Nam, Chang-Yong; Pang, Yutong T.; Hoy, Jessica; Eisaman, Matthew D.; Black, Charles T.; Sfeir, Matthew Y.

2014-01-01

203

Characterizing a large shear-zone with seismic and magnetotelluric methods: The case of the Dead Sea Transform  

USGS Publications Warehouse

Seismic tomography, imaging of seismic scatterers, and magnetotelluric soundings reveal a sharp lithologic contrast along a ???10 km long segment of the Arava Fault (AF), a prominent fault of the southern Dead Sea Transform (DST) in the Middle East. Low seismic velocities and resistivities occur on its western side and higher values east of it, and the boundary between the two units coincides partly with a seismic scattering image. At 1-4 km depth the boundary is offset to the east of the AF surface trace, suggesting that at least two fault strands exist, and that slip occurred on multiple strands throughout the margin's history. A westward fault jump, possibly associated with straightening of a fault bend, explains both our observations and the narrow fault zone observed by others. Copyright 2005 by the American Geophysical Union.

Maercklin, N.; Bedrosian, P.A.; Haberland, C.; Ritter, O.; Ryberg, T.; Weber, M.; Weckmann, U.

2005-01-01

204

Incomplete nuclear transformation of human spermatozoa in oligo-astheno-teratospermia: characterization by indirect immunofluorescence of chromatin and thiol status  

Microsoft Academic Search

BACKGROUND Sperm heterogeneity in the human, as observed in oligo-astheno-teratozoospermia (OAT), is associated with hypospermatogenesis. METHODS The chromatin of sperm from OAT and normospermic males was characterized with antibodies specific for nucleosomes, the histone H3.1\\/H3.2 isoform, histone TH2B, apoptosis-associated H4 acetylation (KM-2) and protamines. Subsequently, sperm samples were stained with the thiol-specific fluorochrome monobromobimane (mBBr) before and after reduction with

L. Ramos; G. W. van der Heijden; A. Derijck; J. H. M. Berden; J. A. M. Kremer; J. van der Vlag; P. de Boer

2008-01-01

205

Continuous wavelet-like filter for a spherical surface and its application to localized admittance function on Mars  

Microsoft Academic Search

We have developed a 2D isotropic continuous wavelet-like transform for a spherical surface. The transform is simply defined as the surface convolution between the original field and a kernel, based on the zeroth-order Bessel function with a spherical correction. This spherical correction violates the geometric similarity for the various scales of the kernels, which becomes more apparent at longer wavelengths.

Motoyuki Kido; David A. Yuen; Alain P. Vincent

2003-01-01

206

Innovative analytical methodology combining micro-x-ray diffraction, scanning electron microscopy-based mineral maps, and diffuse reflectance infrared fourier transform spectroscopy to characterize archeological artifacts.  

PubMed

Excavations at the 14th century Moorish rampart (Granada, Spain) unearthed a brick oven alongside black ash and bone stratigraphic layers. In situ evidence suggests the oven served to fabricate a wall coating including powdered burnt bones. Original ad hoc analyses improved on conventional methods were used to confirm this hypothesis. These methods enable (i) nondestructive micro-X-ray diffraction (mu-XRD) for fast mineralogical data acquisition (approximately 10 s) and moderately high spatial (approximately 500 microm) resolution and (ii) identification and imaging of crystalline components in sample cross-sections via mineral maps, yielding outstanding visualization of grain distribution and morphology in composite samples based on scanning electron microscopy-energy dispersion X-ray spectrometry (SEM-EDX) elemental maps. Benefits are shown for applying diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) vs transmittance-FT-IR (T-FT-IR) to analyze organic and inorganic components in single samples. Complementary techniques to fully characterize artifacts were gas chromatography/mass spectroscopy (GC/MS), optical microscopy (OM), conventional powder XRD, and (14)C dating. Bone-hydroxyapatite was detected in the coating. Mineralogical transformations in the bricks indicate oven temperatures well above 1000 degrees C, supporting the hypothesis. PMID:19099407

Cardell, Carolina; Guerra, Isabel; Romero-Pastor, Julia; Cultrone, Giuseppe; Rodriguez-Navarro, Alejandro

2009-01-15

207

Efficient heterologous transformation of Chlamydomonas reinhardtii npq2 mutant with the zeaxanthin epoxidase gene isolated and characterized from Chlorella zofingiensis.  

PubMed

In the violaxanthin cycle, the violaxanthin de-epoxidase and zeaxanthin epoxidase catalyze the inter-conversion between violaxanthin and zeaxanthin in both plants and green algae. The zeaxanthin epoxidase gene from the green microalga Chlorella zofingiensis (Czzep) has been isolated. This gene encodes a polypeptide of 596 amino acids. A single copy of Czzep has been found in the C. zofingiensis genome by Southern blot analysis. qPCR analysis has shown that transcript levels of Czzep were increased after zeaxanthin formation under high light conditions. The functionality of Czzep gene by heterologous genetic complementation in the Chlamydomonas mutant npq2, which lacks zeaxanthin epoxidase (ZEP) activity and accumulates zeaxanthin in all conditions, was analyzed. The Czzep gene was adequately inserted in the pSI105 vector and expressed in npq2. The positive transformants were able to efficiently convert zeaxanthin into violaxanthin, as well as to restore their maximum quantum efficiency of the PSII (Fv/Fm). These results show that Chlamydomonas can be an efficient tool for heterologous expression and metabolic engineering for biotechnological applications. PMID:23118714

Couso, Inmaculada; Cordero, Baldo F; Vargas, María Ángeles; Rodríguez, Herminia

2012-09-01

208

Biochemical characterization of the Drosophila dpp protein, a member of the transforming growth factor beta family of growth factors.  

PubMed Central

The decapentaplegic (dpp) gene of Drosophila melanogaster is required for pattern formation in the embryo and for viability of the epithelial cells in the imaginal disks. The dpp protein product predicted from the DNA sequence is similar to members of a family of growth factors that includes transforming growth factor beta (TGF-beta). We have produced polyclonal antibodies to a recombinant dpp protein made in bacteria and used a metallothionein promoter to express a dpp cDNA in Drosophila S2 cells. Similar to other proteins in the TGF-beta family, the dpp protein produced by the Drosophila cells was proteolytically cleaved, and both portions of the protein were secreted from the cells. The amino-terminal 47-kilodalton (kDa) peptide was found in the medium and in the proteins adhering to the plastic petri dish. The carboxy-terminal peptide, the region with sequence similarity to the active ligand portion of TGF-beta, was found extracellularly as a 30-kDa homodimer. Most of the 30-kDa homodimer was in the S2 cell protein adsorbed onto the surface of the plastic dish. The dpp protein could be released into solution by increased salt concentration and nonionic detergent. Under these conditions, the amino-terminal and carboxy-terminal portions of dpp were not associated in a stable complex. Images PMID:1692958

Panganiban, G E; Rashka, K E; Neitzel, M D; Hoffmann, F M

1990-01-01

209

Characterization of a new melanocyte-specific gene (QNR-71) expressed in v-myc-transformed quail neuroretina.  

PubMed Central

Quail neuroretina cells (QNR) infected with the v-myc-expressing retrovirus MC29 become pigmented after several passages in vitro. After differential screening of a cDNA library constructed from these cells, we have isolated a cDNA clone (QNR-71) which identifies an RNA expressed only in the pigmented layer of the retina and in the epidermis. This gene can also be induced in other cell types transformed by MC29, suggesting that QNR-71 may be regulated by the v-myc protein. Sequence analysis showed that the QNR-71 cDNA exhibits stretches of homologies with melanosomal proteins encoding genes. From bacterially expressed QNR-71 peptides we obtained rabbit antisera able to specifically recognize two proteins of 95 and 100 kDa in pigmented retinal cells, but not in the neuroretina. To study the regulation of QNR-71, we used promoter fragments linked to the CAT reporter gene, in transient co-expression assay. We observed an increase in CAT expression with a c-MYC and microphtalmia (mi) expression vectors. Both MYC and mi activate the QNR-71 promoter through direct binding to a CATGTG site present in the promoter fragment. Images PMID:8670835

Turque, N; Denhez, F; Martin, P; Planque, N; Bailly, M; Bègue, A; Stéhelin, D; Saule, S

1996-01-01

210

Efficient Heterologous Transformation of Chlamydomonas reinhardtii npq2 Mutant with the Zeaxanthin Epoxidase Gene Isolated and Characterized from Chlorella zofingiensis  

PubMed Central

In the violaxanthin cycle, the violaxanthin de-epoxidase and zeaxanthin epoxidase catalyze the inter-conversion between violaxanthin and zeaxanthin in both plants and green algae. The zeaxanthin epoxidase gene from the green microalga Chlorella zofingiensis (Czzep) has been isolated. This gene encodes a polypeptide of 596 amino acids. A single copy of Czzep has been found in the C. zofingiensis genome by Southern blot analysis. qPCR analysis has shown that transcript levels of Czzep were increased after zeaxanthin formation under high light conditions. The functionality of Czzep gene by heterologous genetic complementation in the Chlamydomonas mutant npq2, which lacks zeaxanthin epoxidase (ZEP) activity and accumulates zeaxanthin in all conditions, was analyzed. The Czzep gene was adequately inserted in the pSI105 vector and expressed in npq2. The positive transformants were able to efficiently convert zeaxanthin into violaxanthin, as well as to restore their maximum quantum efficiency of the PSII (Fv/Fm). These results show that Chlamydomonas can be an efficient tool for heterologous expression and metabolic engineering for biotechnological applications. PMID:23118714

Couso, Inmaculada; Cordero, Baldo F.; Vargas, María Ángeles; Rodríguez, Herminia

2012-01-01

211

Characterization of Growth-Differentiation Factor 15, a Transforming Growth Factor ? Superfamily Member Induced following Liver Injury  

PubMed Central

We have identified a new murine transforming growth factor ? superfamily member, growth-differentiation factor 15 (Gdf15), that is expressed at highest levels in adult liver. As determined by Northern analysis, the expression of Gdf15 in liver was rapidly and dramatically up-regulated following various surgical and chemical treatments that cause acute liver injury and regeneration. In situ hybridization analysis revealed distinct patterns of Gdf15 mRNA localization that appeared to reflect the known patterns of hepatocyte injury in each experimental treatment. In addition, treatment of two hepatocyte-like cell lines with either carbon tetrachloride or heat shock induced Gdf15 mRNA expression, indicating that direct cellular injury can induce Gdf15 expression in the absence of other cell types, such as inflammatory cells. In order to investigate the potential functions of Gdf15, we created Gdf15 null mice by gene targeting. Homozygous null mice were viable and fertile. Despite the dramatic regulation of Gdf15 expression observed in the partial-hepatectomy and carbon tetrachloride injury models, we found no differences in the injury responses between homozygous null mutants and wild-type mice. Our findings suggest either that Gdf15 does not have a regulatory role in liver injury and regeneration or that Gdf15 function within the liver is redundant with that of other signaling molecules. PMID:10779363

Hsiao, Edward C.; Koniaris, Leonidas G.; Zimmers-Koniaris, Teresa; Sebald, Suzanne M.; Huynh, Thanh V.; Lee, Se-Jin

2000-01-01

212

Weathering trend characterization of medium-molecular weight polycyclic aromatic disulfur heterocycles by Fourier transform ion cyclotron resonance mass spectrometry.  

PubMed

Different weathering factors act to change petroleum composition once it is spilled into the environment. n-Alkanes, biomarkers, low-molecular weight polyaromatic hydrocarbons and sulfur heterocycles compositional changing in the environment have been extensively studied by different researchers and many parameters have been used for oil source identification and monitoring of weathering and biological degradation processes. In this work, we studied the fate of medium-molecular weight polycyclic aromatic disulfur heterocycles (PAS2Hs), up to ca. 900Da, of artificially weathered Flotta North Sea crude oil by ultra high-resolution Fourier transform ion cyclotron resonance mass spectrometry. It was found that PAS2Hs in studied crude oil having double bond equivalents (DBE) from 5 to 8 with a mass range from ca 316 to 582Da were less influenced even after six months artificial weathering experiment. However, compounds having DBEs 12, 11 and 10 were depleted after two, four and six months weathering, respectively. In addition, DBE 9 series was more susceptible to weathering than those of DBE 7 and 8. PMID:24997927

Hegazi, Abdelrahman H; Fathalla, Eiman M; Andersson, Jan T

2014-09-01

213

Response of Pole-Mounted Distribution Transformer to Lightning Overvoltage Dependent on Rated Capacity  

NASA Astrophysics Data System (ADS)

A pole-mounted transformer on a power distribution line is vulnerable to lightning overvoltages, and is one of the most frequently damaged instruments in Japan. Therefore, the response of transformers to the overvoltage draws great concern. By incorporating the modeling for the secondary windings proposed by Mr. Honda et al., the authors develop equivalent circuits of distribution transformers of 10kVA, 20kVA and 30kVA rated capacity based on modal analysis of measured admittance whereby one can evaluate its response to overvoltages on a low-voltage line as well as on a medium-voltage line. The validity of calculated results obtained by using the developed circuits is demonstrated by comparison with experimental results. The response of transformers made by the same manufacturer to the lightning impulse voltage waveforms is influenced by the rated capacity, and the phase and the degree of such influence is demonstrated.

Michishita, Koji; Hiraiwa, Hideo; Hongo, Yasuji

214

Current density-voltage and admittance characteristics of hydrogenated nanocrystalline cubic SiC/crystalline Si heterojunction diodes prepared with varying H2 gas flow rates  

NASA Astrophysics Data System (ADS)

N-doped hydrogenated nanocrystalline cubic SiC (nc-3C-SiC:H) thin films were deposited on p-type crystalline Si (c-Si) substrates by hot-wire chemical vapor deposition from a SiH4/CH4/H2/N2 gas mixture. The current density-voltage and the admittance characteristics of the nc-3C-SiC:H/c-Si heterojunction diodes were investigated. As the H2 gas flow rate (F(H2)) increased from 25 to 100 sccm, the ideality factor and saturation current density deceased from 1.87 to 1.47 and 1.6 × 10-7 to 9.9 × 10-9 A/cm2, respectively. However, they increased to 1.82 and 3.0 × 10-7 A/cm2, respectively, when F(H2) was further increased to 1000 sccm. The relaxation time, evaluated from the admittance characteristics, decreased from 2.9 × 10-5 to 2.4 × 10-6 s with an increase in F(H2). The apparent built-in voltage, evaluated from the capacitance-voltage characteristics, decreased from 1.05 to 0.60 eV. These findings were mainly caused by interfacial defects, generated by a high density of H radicals during the nc-3C-SiC:H deposition process. The interfacial defect density increased with an increase in F(H2), resulting in deterioration of the diode characteristics.

Tabata, Akimori; Imori, Yoshikazu

2015-02-01

215

Modeling Transformation  

E-print Network

pGLO plasmids Bacterial chromosomal DNA Cell membrane #12;Heat-shock @ 42°C IncreasesModeling Transformation What does each step do? #12;Transformation Procedure #12;Transformation Procedure #12;Building Your Model Yarn = chromosomal DNA Beads

Rose, Michael R.

216

Characterization and petrophysical properties of hydrothemally altered lacustrine volcanistic rock in Geyser Valley (Kamchatka) and its transformation by weathering  

NASA Astrophysics Data System (ADS)

Work is devoted to the study of volcano sedimentary hydrothermally altered rocks in Geyser Valley (Kamchatka peninsula, Russia). The Geyser Valley is one of the most unique nature objects in Russia. There are quite large geyser fields. The valley of the river is part of the Uson-Geysernaya depression, where hydrothermal activity is very high. Besides geysers here are hot springs, mud pots and fumarols. In the late Pleistocene (about 45-35 thousand years ago) the lake was located in the site of the modern valley of the Geysernaya river, where sediments accumulated intensively. Sedimentary material came from several sources in the form of pyroclastic flows, ash falls, was supplied by permanent and temporary water streams. The total deposit thickness reached several hundred meters. In the late Pleistocene there was breakthrough of reservoir and further conditions for the lacustrine deposits formation did not arose. Later the rocks were intensively processed by thermal water. In 2007 large landslide was formed in lower part of the Geysernaya River on their left slope. Deposits of Geysernaya (Q34grn) series and Pemsovaya (Q34pmz) series were involved in landslide displacement. The headscarp was formed up to 100 m and a length of 800 m, exposing the volcano-sedimentary section of hydrothermally altered rocks - a unique opportunity for sampling and subsequent laboratory study. Thickness of lake sediments is interbedding of coarse-grain, medium-grain, fine-grain tuffites predominantly acidic composition. The study of thin sections revealed that all samples are lithoclastic and vitroclastic hydrothermally altered tuffits. Currently, the primary minerals and volcanic glass is largely replaced by clay minerals of the smectite group. Pores and cracks are made zeolites (heulandite and clinoptilolite). All this points to the low-temperature (<200 ° C) hydrothermal conditions with a pH near neutral. Tyere are acid plagioclase and quartz in most samples The high content of smectite causes high hygroscopy of deposits. Rocks are highly porous - of 37-65%, primarily low density - 0,9-1,65 g/cm3 wave velocities - from 0.74 km/s for porous to 3.42 km/sec for dense varieties. All samples are characterized by low strength characteristics: uniaxial compressive strength - 1.2 - 21.7 MPa, uniaxial tension - 0,6-4,7 MPa. By water saturation strength decreases rapidly. Soft coefficient ranges from 0.22 to 0.57. Proving to be on the land surface as a result of slope deformation, volcanic-sedimentary hydrothermally altered rocks are destroyed quickly by precipitation and temperature fluctuations Rock turned to sand, silt and clay depending on the original composition. It was found that often weathered to clayey state tuffites inherit structural and textural features of the primary species. The composition also varies: increased content of clay minerals (to 90%), decreasing the content of zeolites (not to exceed 10%). Quartz and plagioclase form sans fraction. Physical and mechanical properties vary widely: the density of the soil increases slightly up to 1,57-1,59 g/cm3 for sands, 1,2-1,79 g/cm3 for clays, porosity of 51-52% and 49-78% respectively, moisture 22-23% and 43-98/ Clays are in a state of semi-solid to fluid. The high content of smectite determines high plastic properties. Plasticity Index varies widely from 11 to 57. Cohesion and the internal friction angle obtained from shear tests also change widely. For clayey sand grip reaches 137 kPa, internal friction angle - 17 degrees. In clay grip ranges from 13 kPa to 120 kPa, and the internal friction angle - from 11 degrees to 31 degrees. Large variation of properties of the investigated soils is explained by the inhomogeneity of volcano-sedimentary formations both vertically and laterally, varying degrees of hydrothermal alteration and of weathering, fracturing and cracks filling The obtained datas can adequately characterize the volcanic-lacustrine sediments in the valley of the Geysernaya river and use them in calculations of slope stability and for and geological mapping.

Gvozdeva, Irina; Zerkal, Oleg; Samarin, Evgeny

2013-04-01

217

Characterization of organic composition in snow and surface waters in the Athabasca Oil Sands Region, using ultrahigh resolution Fourier transform mass spectrometry.  

PubMed

This study was conducted to characterize the composition of dissolved organic compounds present in snow and surface waters in the Athabasca Oil Sands Region (AOSR) with the goal of identifying whether atmospherically-derived organic compounds present in snow are a significant contributor to the compounds detected in surface waters (i.e., rivers and lakes). We used electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR MS) to characterize the dissolved organic compound compositions of snow and surface water samples. The organic profiles obtained for the snow samples show compositional differences between samples from near-field sites (<5km from oil sands activities) and those from more distant locations (i.e., far-field sites). There are also significant compositional differences between samples collected in near-field sites and surface water samples in the AOSR. The composition of dissolved organic compounds at the upstream Athabasca River site (i.e., Athabasca River at Athabasca) is found to be different from samples obtained from downstream sites in the vicinity of oil sands operations (i.e., Athabasca River at Fort McMurray and Athabasca River at Firebag confluence). The upstream Athabasca River sites tended to share some compositional similarities with far-field snow deposition, while the downstream Athabasca River sites are more similar to local lakes and tributaries. This contrast likely indicates the relative role of regional snowmelt contributions to the Athabasca River vs inputs from local catchments in the reach downstream of Fort McMurray. PMID:25747374

Yi, Y; Birks, S J; Cho, S; Gibson, J J

2015-06-15

218

Characterization of phospholipid bilayer formation on a thin film of porous SiO2 by reflective interferometric Fourier transform spectroscopy (RIFTS).  

PubMed

Classical methods for characterizing supported artificial phospholipid bilayers include imaging techniques such as atomic force microscopy and fluorescence microscopy. The use in the past decade of surface-sensitive methods such as surface plasmon resonance and ellipsometry, and acoustic sensors such as the quartz crystal microbalance, coupled to the imaging methods, have expanded our understanding of the formation mechanisms of phospholipid bilayers. In the present work, reflective interferometric Fourier transform spectrocopy (RIFTS) is employed to monitor the formation of a planar phospholipid bilayer on an oxidized mesoporous Si (pSiO(2)) thin film. The pSiO(2) substrates are prepared as thin films (3 ?m thick) with pore dimensions of a few nanometers in diameter by the electrochemical etching of crystalline silicon, and they are passivated with a thin thermal oxide layer. A thin film of mica is used as a control. Interferometric optical measurements are used to quantify the behavior of the phospholipids at the internal (pores) and external surfaces of the substrates. The optical measurements indicate that vesicles initially adsorb to the pSiO(2) surface as a monolayer, followed by vesicle fusion and conversion to a surface-adsorbed lipid bilayer. The timescale of the process is consistent with prior measurements of vesicle fusion onto mica surfaces. Reflectance spectra calculated using a simple double-layer Fabry-Perot interference model verify the experimental results. The method provides a simple, real-time, nondestructive approach to characterizing the growth and evolution of lipid vesicle layers on the surface of an optical thin film. PMID:22486481

Pace, Stéphanie; Seantier, Bastien; Belamie, Emmanuel; Lautrédou, Nicole; Sailor, Michael J; Milhiet, Pierre-Emmanuel; Cunin, Frédérique

2012-05-01

219

Structural characterization of cyclosporin A, C and microbial bio-transformed cyclosporin A analog AM6 using HPLC-ESI-ion trap-mass spectrometry.  

PubMed

Cyclosporin A (CyA), a cyclic undecapeptide produced by a number of fungi, contains 11 unusual amino acids, and has been one of the most commonly prescribed immunosuppressive drugs. To date, there are over sixty different analogs reported as congeners and analogs resulting from precursor-directed biosynthesis, human CYP-mediated metabolites, or microbial bio-transformed analogs. However, there is still a need for more structurally diverse CyA analogs in order to discover new biological potentials and/or improve the physicochemical properties of the existing cyclosporins. As a result of the complexity of the resulting mass spectrometric (MS) data caused by its unusual amino acid composition and its cyclic nature, structural characterization of these cyclic peptides based on fragmentation patterns using multiple tandem MS analyses is challenging task. Here, we describe, an efficient HPLC-ESI-ion trap MS(n) (up to MS(8)) was developed for the identification of CyA and CyC, a (Thr(2))CyA congener in which L-aminobutyric acid (Abu) is replaced by L-threonine (Thr). In addition, we examined the fragmentation patterns of a CyA analog obtained from the cultivation of a recombinant Streptomyces venezuelae strain fed with CyA, assigning this analog as (?-hydroxy-MeLeu(6))CyA (otherwise, known as an human CYP metabolite AM6). This is the first report on both the MS(n)-aided identification of CyC and the structural characterization of a CyA analog by employing HPLC-ESI-ion trap MS(n) analysis. PMID:24725868

Ahn, Eun Young; Shrestha, Anil; Hoang, Nguyen Huu; Huong, Nguyen Lan; Yoon, Yeo Joon; Park, Je Won

2014-06-01

220

Comparing Laser Desorption Ionization and Atmospheric Pressure Photoionization Coupled to Fourier Transform Ion Cyclotron Resonance Mass Spectrometry To Characterize Shale Oils at the Molecular Level  

USGS Publications Warehouse

Laser desorption ionization (LDI) coupled to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to analyze shale oils. Previous work showed that LDI is a sensitive ionization technique for assessing aromatic nitrogen compounds, and oils generated from Green River Formation oil shales are well-documented as being rich in nitrogen. The data presented here demonstrate that LDI is effective in ionizing high-double-bond-equivalent (DBE) compounds and, therefore, is a suitable method for characterizing compounds with condensed structures. Additionally, LDI generates radical cations and protonated ions concurrently, the distribution of which depends upon the molecular structures and elemental compositions, and the basicity of compounds is closely related to the generation of protonated ions. This study demonstrates that LDI FT-ICR MS is an effective ionization technique for use in the study of shale oils at the molecular level. To the best of our knowledge, this is the first time that LDI FT-ICR MS has been applied to shale oils.

Cho, Yunjo; Jin, Jang Mi; Witt, Matthias; Birdwell, Justin E.; Na, Jeong-Geol; Roh, Nam-Sun; Kim, Sunghwan

2013-01-01

221

Characterization of organic material in ice core samples from North America, Greenland, and Antarctica using ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry  

NASA Astrophysics Data System (ADS)

Historically, it has been an analytical challenge to detect and identify the organic components present in ice cores, due to the low abundance of organic carbon. In order to detect and characterize the small amounts of organic matter in ice cores, ultra high resolution instrumentation is required. Here we report the use of ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry, coupled with electrospray ionization, to identify the molecular formulas and compound classes of organic matter in both modern and ancient ice core and glacial samples from Wyoming, Greenland, and Antarctica. A suite of 21 samples were analyzed and thousands of distinct molecular species were identified in each sample, providing clues to the nature and sources of organic matter in these regions. Major biochemical classes of compounds were detected such as lignins, tannins, carbohydrates, proteins, lipids, unsaturated hydrocarbons, and condensed aromatic compounds. We will compare the nature of the organic matter present in the samples in order to determine the differences in dominant organic compound classes and in heteroatom (nitrogen and sulfur) abundance. By analyzing these differences, it is possible to investigate the historical patterns of organic matter deposition/source, and begin to investigate the influence of climate change, volcanism, and onset of the industrial revolution on the nature of organic matter preserved in ice cores.

Catanzano, V.; Grannas, A. M.; Sleighter, R. L.; Hatcher, P. G.

2013-12-01

222

Characterization of uranyl(VI) nitrate complexes in a room temperature ionic liquid using attenuated total reflection-Fourier transform infrared spectrometry.  

PubMed

Room temperature ionic liquids form potentially important solvents in novel nuclear waste reprocessing methods, and the solvation, speciation, and complexation behaviors of actinides and lanthanides in room temperature ionic liquids is of current interest. In this study, the coordination environment of uranyl(VI) in solutions of the room temperature ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide containing either tetrabutylammonium nitrate or nitric acid was characterized using attenuated total reflection-Fourier transform infrared spectrometry. Both UO(2)(NO(3))(2) and UO(2)(NO(3))(3)(-) species were detected in solutions containing tetrabutylammonium nitrate. ?(as)(UO(2)) for these two species were found to lie at 951 and 944 cm(-1), respectively, while ?(as)(UO(2)) arising from uranyl(VI) coordinated by bis(trifluoromethylsulfonyl)imide anions in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide was found to lie at 968 cm(-1). In solutions containing nitric acid, only UO(2)(NO(3))(2) was detected, due to the high water content. The UO(2)(NO(3))(+) species was not detected under the conditions used in this study. From the results shown here, we conclude that infrared spectroscopy forms a valuable addition to the suite of tools currently used to study the chemical behavior of uranyl(VI) in room temperature ionic liquids. PMID:20722398

Quach, Donna L; Wai, Chien M; Pasilis, Sofie P

2010-09-20

223

Characterization of Nuclear Localization Signals (NLSs) and Function of NLSs and Phosphorylation of Serine Residues in Subcellular and Subnuclear Localization of Transformer-2? (Tra2?)*  

PubMed Central

The serine/arginine-rich (SR) proteins are one type of major actors in regulation of pre-mRNA splicing. Their functions are closely related to the intracellular spatial organization. The RS domain and phosphorylation status of SR proteins are two critical factors in determining the subcellular distribution. Mammalian Transformer-2? (Tra2?) protein, a member of SR proteins, is known to play multiple important roles in development and diseases. In the present study, we characterized the subcellular and subnuclear localization of Tra2? protein and its related mechanisms. The results demonstrated that in the brain the nuclear and cytoplasmic localization of Tra2? were correlated with its phosphorylation status. Using deletional mutation analysis, we showed that the nuclear localization of Tra2? was determined by multiple nuclear localization signals (NLSs) in the RS domains. The point-mutation analysis disclosed that phosphorylation of serine residues in the NLSs inhibited the function of NLS in directing Tra2? to the nucleus. In addition, we identified at least two nuclear speckle localization signals within the RS1 domain, but not in the RS2 domain. The nuclear speckle localization signals determined the localization of RS1 domain-contained proteins to the nuclear speckle. The function of the signals did not depend on the presence of serine residues. The results provide new insight into the mechanisms by which the subcellular and subnuclear localization of Tra2? proteins are regulated. PMID:23396973

Li, Shu-Jing; Qi, Yao; Zhao, Jing-Jing; Li, Ya; Liu, Xiao-Yan; Chen, Xian-Hua; Xu, Ping

2013-01-01

224

Transformation of a liposomal dispersion containing ibuprofen lysinate and phospholipids into mixed micelles - physico-chemical characterization and influence on drug permeation through excised human stratum corneum.  

PubMed

Our study is meant as a contribution to the investigation of molecular association of phospholipids and amphiphilic substances like, e.g. non-steroidal anti-inflammatory drugs. Our research focused on physico-chemical characterization of ternary systems containing ibuprofen lysinate, lecithin and water. The influence of the resulting microstructures on drug release and permeation through excised human stratum corneum was also investigated. Depending on the mixing ratio different physical states (lamellar and hexagonal liquid crystals, micellar solutions, liposomal dispersions and biphasic systems) were determined by gross, polarizing microscopic and small angle-X-ray analysis. A special emphasis was laid upon the storage-induced transformation of liposomal dispersions into mixed micellar solutions and its influence on drug release and permeation. A model for the transformation process is presented. Drug release of the liposomal dispersion (Da=1.1x10-5 cm2/s) and of the identically composed mixed micellar solution (Da=2.9x10-5 cm2/s) was delayed compared with the data of the aqueous drug solution (Da=4.7x10-5 cm2/s). Because of the association of ibuprofen lysinate molecules with phospholipid molecules within the liposomal and the mixed micellar system the share of free ibuprofen lysinate monomers, which can pass through the dialysis membrane in the release experiment, is markedly reduced. The results of permeation experiments of these systems, however, did not correspond to the release data. The permeability of the mixed micellar solution rose after 6 weeks of storage (P=4.2x10-8 cm/s), and almost reached the permeation of the aqueous solution (P=3.9x10-8 cm/s), whereas the permeation of the liposomal dispersion was very slow (P=1.5x10-8 cm/s). The different colloidal microstructures of the formulations obviously resulted in divergent interactions with the permeation barrier - the stratum corneum - and subsequently in different permeation behavior. PMID:9795056

Stoye, I; Schröder, K; Müller-Goymann, C C

1998-09-01

225

Reservoir characterization using wavelet transforms  

E-print Network

analysis techniques, to interpret cyclicity, determine its controlling factors, and detect zone boundaries. We tested the cyclostratigraphic assessments using well log and core data from a well in a fluvio-eolian sequence in the Ormskirk Sandstone, Irish...

Rivera Vega, Nestor

2004-09-30

226

Transformation Composition  

E-print Network

Proc. AGTIVE'99, to appear in LNCS Graph Transformation Modules and their Composition ? Frank,knirsch,kreo,kuskeg@informatik.uni-bremen.de Abstract. In this paper, we investigate the notion of transformation modules as a structuring principle. Based on the notion of transformation units, a concept that allows to specify binary relations on graphs

Drewes, Frank

227

transformations: representations  

E-print Network

Overview 1. Number transformations: from one base to another 2. Integer representations 3. Real rate, caches... #12; ECS 50, Discussion on 4/25 2 Integer Transformation: From Decimal to Binary Let, Discussion on 4/25 3 Integer Transformation: From Binary to Decimal Compute the weight of each digit position

Nguyen, Dat H.

228

Characterization of skin abnormalities in a mouse model of osteogenesis imperfecta using high resolution magnetic resonance imaging and Fourier transform infrared imaging spectroscopy.  

PubMed

Evaluation of the skin phenotype in osteogenesis imperfecta (OI) typically involves biochemical measurements, such as histologic or biochemical assessment of the collagen produced from biopsy-derived dermal fibroblasts. As an alternative, the current study utilized non-invasive magnetic resonance imaging (MRI) microscopy and optical spectroscopy to define biophysical characteristics of skin in an animal model of OI. MRI of skin harvested from control, homozygous oim/oim and heterozygous oim/+ mice demonstrated several differences in anatomic and biophysical properties. Fourier transform infrared imaging spectroscopy (FT-IRIS) was used to interpret observed MRI signal characteristics in terms of chemical composition. Differences between wild-type and OI mouse skin included the appearance of a collagen-depleted lower dermal layer containing prominent hair follicles in the oim/oim mice, accounting for 55% of skin thickness in these. The MRI magnetization transfer rate was lower by 50% in this layer as compared to the upper dermis, consistent with lower collagen content. The MRI transverse relaxation time, T2, was greater by 30% in the dermis of the oim/oim mice compared to controls, consistent with a more highly hydrated collagen network. Similarly, an FT-IRIS-defined measure of collagen integrity was 30% lower in the oim/oim mice. We conclude that characterization of phenotypic differences between the skin of OI and wild-type mice by MRI and FT-IRIS is feasible, and that these techniques provide powerful complementary approaches for the analysis of the skin phenotype in animal models of disease. PMID:21845737

Canuto, H C; Fishbein, K W; Huang, A; Doty, S B; Herbert, R A; Peckham, J; Pleshko, N; Spencer, R G

2012-01-01

229

Characterization of low molecular weight dissolved natural organic matter along the treatment trait of a waterworks using Fourier transform ion cyclotron resonance mass spectrometry.  

PubMed

Dissolved natural organic matter (DOM), particularly the low molecular weight DOM, can affect the performance of water treatment processes and serve as a main precursor of disinfection by-products (DBPs) during chlorination. In this study, electrospray ionization coupled to Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) was used to characterize the low molecular weight DOM along the treatment trait of a conventional drinking water treatment plant. The ESI FT-ICR MS data showed that various C, H, O-only class species were the major components in the source water. According to the van Krevelen diagram analysis, lignin- and tannin-like compounds were the most abundant components. Within an isobaric group, the DOM molecules with a high degree of oxidation (high O/C value) were preferentially removed during coagulation, while those with low degree of oxidation were found to be more reactive toward chlorine. In addition, 357 one-chlorine containing products and 199 two-chlorine containing products formed during chlorination were detected in the chlorination effluent sample at a high confidence level. The chlorinated products can be arranged into series, suggesting that they were originated from C, H, O-only precursor compounds, which were in series related by the replacement of CH(4) against oxygen. For the first time, this study explored the behavior of low molecular weight DOM along a drinking water treatment trait on the molecular level, and revealed the presence of abundant unknown chlorinated products, which are probably rich in carboxylic and phenolic groups, in drinking water. PMID:22853975

Zhang, Haifeng; Zhang, Yahe; Shi, Quan; Ren, Shuoyi; Yu, Jianwei; Ji, Feng; Luo, Wenbin; Yang, Min

2012-10-15

230

Mossbauer and XRD characterization of the phase transformations in a Fe-Mn-Al-C-Mo-Si-Cu as cast alloy during tribology test  

NASA Astrophysics Data System (ADS)

In present study Fe-29.0Mn-6Al-0.9C-1.8Mo-1.6Si-0.4Cu (%w) alloy was obtained after melted in an induction furnace, and then molded as an ingot. From the as cast ingot it were cut samples for the different characterization measurements. The microstructure of the as-cast sample is of dendritic type and its XRD pattern was refined with the lines of the austenite, with a big volumetric fraction, and the lines of the martensite, with small volumetric fraction. The Mössbauer spectrum of the sample was fitted with a broad singlet which corresponds to disordered austenite. After the tribology test, its XRD pattern was refined with the lines of two austenite phases, one similar to the previous one and other with bigger lattice parameter. The total volumetric fraction of the austenite is smaller than that obtained for sample without wear. It was added the lines of the martensite phase with bigger volumetric fraction than that of the previous sample. The Mössbauer spectrum of the weared sample was fitted with two paramagnetic sites which correspond to the two Fe austenite phases and a hyperfine magnetic field distribution which is associated to the disordered original martensite and the new one which appears in the surface as a consequence of the wear process. These results show that during wear process the original austenite phase is transformed in martensite and in a new austenite phase. The increases of the martensitic phase improves mechanical properties and wear behavior.

Ramos, J.; Piamba, J. F.; Sánchez, H.; Alcazar, G. A. Pérez

2015-01-01

231

Optical characterization of free electron concentration in heteroepitaxial InN layers using Fourier transform infrared spectroscopy and a 2 × 2 transfer-matrix algebra  

NASA Astrophysics Data System (ADS)

Fourier Transform Infrared (FTIR) reflectance spectroscopy has been implemented as a non-destructive, non-invasive, tool for the optical characterization of a set of c-plane InN single heteroepitaxial layers spanning a wide range of thicknesses (30-2000 nm). The c-plane (0001) InN epilayers were grown by plasma-assisted molecular beam epitaxy (PAMBE) on GaN(0001) buffer layers which had been grown on Al2O3(0001) substrates. It is shown that for arbitrary multilayers with homogeneous anisotropic layers having their principal axes coincident with the laboratory coordinates, a 2 × 2 matrix algebra based on a general transfer-matrix method (GTMM) is adequate to interpret their optical response. Analysis of optical reflectance in the far and mid infrared spectral range has been found capable to discriminate between the bulk, the surface and interface contributions of free carriers in the InN epilayers revealing the existence of electron accumulation layers with carrier concentrations in mid 1019 cm-3 at both the InN surface and the InN/GaN interface. The spectra could be fitted with a three-layer model, determining the different electron concentration and mobility values of the bulk and of the surface and the interface electron accumulation layers in the InN films. The variation of these values with increasing InN thickness could be also sensitively detected by the optical measurements. The comparison between the optically determined drift mobility and the Hall mobility of the thickest sample reveals a value of rH = 1.49 for the Hall factor of InN at a carrier concentration of 1.11 × 1019 cm-3 at 300° ?.

Katsidis, C. C.; Ajagunna, A. O.; Georgakilas, A.

2013-02-01

232

Characterization of the interface structure of enzyme-inhibitor complex by using hydrogen-deuterium exchange and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry.  

PubMed Central

We investigated the interaction between a thiol protease inhibitor, cystatin, and its target enzyme, papain, by hydrogen-deuterium (H/D) exchange in conjunction with successive analysis by collision-induced dissociation (CID) in an rf-only hexapole ion guide with electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR MS). The deuterium incorporation into backbone amide hydrogens of cystatin was analyzed at different time points in the presence or absence of papain, examining the mass of each fragment produced by hexapole-CID. In the absence of papain, amide hydrogens in short amino-terminal fragments, such as b10(2+) and b12(2+), were highly deuterated within 1 min. Although fewer fragments were observed for the cystatin-papain complex in the hexapole-CID spectra, significant reductions in initial deuterium content were recognized throughout the sequence of cystatin. This suggests that complex formation restricted the flexibility of the whole cystatin molecule. Detailed analyses revealed that a marked reduction in deuterium content in the region of residues 1-10 persisted for hours, suggesting that the flexible N-terminal region was tightly fixed in the binding pocket with hydrogen bonds. Our results are consistent with those of previous studies on the structure and inhibition mechanism of cystatin. We demonstrated here that enzyme-inhibitor interactions can be characterized by H/D exchange in combination with CID in a hexapole ion guide using ESI-FTICR MS rapidly and using only a small amount of sample. PMID:11206071

Akashi, S.; Takio, K.

2000-01-01

233

Design and Characterization of a High-power Laser-induced Acoustic Desorption (LIAD) Probe Coupled with a Fourier-transform Ion Cyclotron Resonance Mass Spectrometer  

PubMed Central

We report here the construction and characterization of a high-power laser-induced acoustic desorption (LIAD) probe designed for Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometers to facilitate analysis of non-volatile, thermally labile compounds. This “next generation” LIAD probe offers significant improvements in sensitivity and desorption efficiency for analytes with larger molecular weights via the use of higher laser irradiances. Unlike the previous probes which utilized a power limiting optical fiber to transmit the laser pulses through the probe, this probe employs a set of mirrors and a focusing lens. At the end of the probe, the energy from the laser pulses propagates through a thin metal foil as an acoustic wave, resulting in desorption of neutral molecules from the opposite side of the foil. Following desorption, the molecules can be ionized by electron impact or chemical ionization. Almost an order of magnitude greater power density (up to 5.0 × 109 W/cm2) is achievable on the backside of the foil with the high-power LIAD probe compared to the earlier LIAD probes (maximum power density ~9.0 × 108 W/cm2). The use of higher laser irradiances is demonstrated not to cause fragmentation of the analyte. The use of higher laser irradiances increases sensitivity since it results in the evaporation of a greater number of molecules per laser pulse. Measurement of the average velocities of LIAD evaporated molecules demonstrates that higher laser irradiances do not correlate with higher velocities of the gaseous analyte molecules. PMID:17319645

Shea, Ryan C.; Habicht, Steven C.; Vaughn, Weldon E.; Kenttämaa, Hilkka I.

2008-01-01

234

Molecular cloning and characterization of two tropinone reductases in Anisodus acutangulus and enhancement of tropane alkaloid production in AaTRI-transformed hairy roots.  

PubMed

Tropane alkaloids are used medicinally as anticholinergic agents with increasing market demand, so the improvement and production of active components from medicinal plants using molecular biotechnology show great potential for applications that should benefit human healthcare. Two tropinone reductases constitute a branching point in the biosynthesis of tropane alkaloids. In the present paper, we report for the first time the cloning and characterization of two fulllength cDNAs encoding TRI (tropinone reductase I) (GenBank accession number EU424321) and TRII (tropinone reductase II) (GenBank(R) accession number EU424322) from the solanaceous plant Anisodus acutangulus by rapid amplification of cDNA ends. Sequence comparison indicated that AaTRI (A. acutangulus TRI) and AaTRII (A. acutangulus TRII) had high homology with other tropinone reductases from Hyoscyamus niger, Datura stramonium etc., but AaTRI and AaTRII showed identity of only 60.8%. Phylogenetic-tree analysis showed that AaTRI and AaTRII belong to different clusters and have the closest relationship with H. niger TRI and TRII respectively. Expression-pattern analysis showed that AaTRI and AaTRII were expressed in all tissues tested, including root, stem and leaf, but the transcript level of AaTRI was much lower than AaTRII. Expression of AaTRI and AaTRII could be enhanced by methyl jasmonate, with a weak effect for AaTRI and a strong effect for AaTRII. AaTRI-transformed hairy-root lines were accompanied by a mean 1.87-fold higher level of hyoscyamine and a mean 8-fold higher level of scopolamine compared with control roots, indicating that AaTRI is a promising target for genetic engineering to increase tropane alkaloid in A. acutangulus. PMID:19751215

Kai, Guoyin; Li, Li; Jiang, Yuxin; Yan, Xiangming; Zhang, Yan; Lu, Xuan; Liao, Pan; Chen, Jianbo

2009-11-01

235

Transformation Station  

NSDL National Science Digital Library

Shapes are all over the place in geometry. One way we can move these shapes is with transformations. Use these games to help you practice and identify the three types of transformations: reflections, translations, and rotations. Just as a refresher, watch this video about transformational geometry: Gingerbread Transformer! When you are ready...start playing the games!! Take it to the court for Basketball Geometry! Once you type in your name and choose a player, pay attention to the coach for a review on the three types of transformations. While you play, ...

Mrs. Stroud

2010-09-01

236

Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Instrumentation and Methods for Structural Characterization of Trapped Biomolecular Ions: Innovative MS\\/MS Techniques, Gas-Phase Hudrogen\\/Deuterium Exchange, and Laser-Induced Fluoresnence  

Microsoft Academic Search

Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) has become a powerful tool for biomolecular structural characterization because of its superior mass resolving power and high mass accuracy. Of particular interest in this work is the optimization of the diverse range of fragmentation techniques available to FT-ICR MS\\/MS, including ion threshing, a novel form of collisionally activated dissociation (CAD),

Melinda A. McFarland

2004-01-01

237

Modeling and Characterization of On-Chip Transformers Sunderarajan S. Mohan, C. Patrick Yue, Maria del Mar Hershenson, S. Simon Wong, and Thomas H. Lee  

E-print Network

with measurements for a vari- ety of transformer configurations. The rising demand for low-cost radio frequency integrated circuits (RF-IC's) has generated tremendous interest in on-chip passive com- ponents. Transformers-to-substrate capac- itances, resonance frequencies, symmetry and area. Our models and coupling expressions allow

Lee, Thomas H.

238

Signal processing on graphs: Transforms and tomograms  

E-print Network

Using projections on the (generalized) eigenvectors associated to matrices that characterize the topological structure, several authors have constructed generalizations of the Fourier transform on graphs. By exploring mappings of the spectrum of these matrices we show how to construct more general transforms, in particular wavelet-like transforms on graphs. For time-series, tomograms, a generalization of the Radon transforms to arbitrary pairs of non-commuting operators, are positive bilinear transforms with a rigorous probabilistic interpretation which provide a full characterization of the signals and are robust in the presence of noise. Here the notion of tomogram transform is also extended to signals on arbitrary graphs

Mendes, R Vilela; Araújo, Tanya

2014-01-01

239

Transformational Grammar and Cognitive Psycholinguistics.  

ERIC Educational Resources Information Center

An overview of Noam Chomsky's theories about transformational grammar and phonology is given. Since Chomsky was interested in characterizing what it is to know a language, the ways in which we demonstrate knowledge of our native language are discussed in detail. Particular emphasis is placed on describing how the transformational approach actually…

Lester, Mark

1973-01-01

240

Animating Transformations  

NSDL National Science Digital Library

In most introductory linear algebra courses, prominent applications of transformations or mappings are moving (rotating, reflecting, translating), resizing (contracting, expanding), changing the shape (shearing, projecting) objects in the plane. A typical problem in such courses is to write the matrix of a transformation that changes points in such prescribed ways. The goal of this demo is to help students more easily visualize such transformations on a wide class of plane objects.

Roberts, Lila F.

2003-01-24

241

CHARACTERIZATION OF PCB (POLYCHLORINATED BIPHENYL) TRANSFORMER/CAPACITOR FLUIDS AND CORRELATION WITH PCDDS (POLYCHLORINATED DIBENZO-P-DIOXINS) AND PCDFS (POLYCHLORINATED DIBENZOFURANS) IN SOOT  

EPA Science Inventory

Dielectric fluids in transformers and capacitors often contain polychlorinated biphenyls (PCBs) or chlorobenzenes. These substances may generate polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs) under certain conditions of combustion/pyrolysis. W...

242

Transformational leadership.  

PubMed

This month, the director of the Magnet Recognition Program® takes an in-depth look at the Magnet® model component transformational leadership. The author examines the expectations for Magnet organizations around this component. What are the qualities that make a nursing leader truly transformational, and what is the best approach to successfully lead a healthcare organization through today's volatile healthcare environment? PMID:22094611

Luzinski, Craig

2011-12-01

243

Transformational Events  

ERIC Educational Resources Information Center

Transformational Events is a new pedagogic pattern that explains how innovations (and other transformations) happened. The pattern is three temporal stages: an interval of increasingly unsatisfactory ad hoc solutions to a persistent problem (the "mess"), an offer of an invention or of a new way of thinking, and a period of widespread adoption and…

Denning, Peter J.; Hiles, John E.

2006-01-01

244

Lightweight transformer  

SciTech Connect

The technical effort described in this report relates to the program that was performed to design, fabricate, and test a lightweight transformer for Strategic Defense Initiative Organization (SDIO) mission requirements. The objectives of this program were two-fold: (1) design and fabricate a lightweight transformer using liquid hydrogen as the coolant; and (2) test the completed transformer assembly with a low voltage, dc power source. Although the full power testing with liquid helium was not completed, the program demonstrated the viability of the design approach. The lightweight transformer was designed and fabricated, and low and moderate power testing was completed. The transformer is a liquid hydrogen cooled air core transformer that uses thin copper for its primary and secondary windings. The winding mass was approximately 12 kg, or 0.03 kg/kW. Further refinements of the design to a partial air core transformer could potentially reduce the winding mass to as low as 4 or 5 kg, or 0.0125 kg/kW. No attempt was made on this program to reduce the mass of the related structural components or cryogenic container. 8 refs., 39 figs., 2 tabs.

Swallom, D.W.; Enos, G.

1990-05-01

245

State space transformations in queueing network modeling  

Microsoft Academic Search

An important problem in queueing network modeling is that of characterizing and analyzing relationships among alternative models of a single system. The problem is approached by developing the concept of a state space transformation, which is a mechanism for expressing the way one model can be mapped into another. After discussing state space transformations in general terms, some important transformations

Jeffrey P. Buzen; Subhash C. Agrawal

1983-01-01

246

Organelle transformation.  

PubMed

The source of genetic information in a plant cell is contained in nucleus, plastids, and mitochondria. Organelle transformation is getting a lot of attention nowadays because of its superior performance over the conventional and most commonly used nuclear transformation for obtaining transgenic lines. Absence of gene silencing, strong predictable transgene expression, and its application in molecular pharming, both in pharmaceutical and nutraceuticals, are some of many advantages. Other important benefits of utilizing this technology include the absence of transgene flow, as organelles are maternally inherited. This may increase the acceptability of organelle transformation technology in the development of transgenic crops in a wider scale all over the globe. As the need for crop productivity and therapeutic compounds increases, organelle transformation may be able to bridge the gap, thereby having a definite promise for the future. PMID:22610643

Bhattacharya, Anjanabha; Kumar, Anish; Desai, Nirali; Parikh, Seema

2012-01-01

247

Transformation Golf  

NSDL National Science Digital Library

In this game students use the isometric transformations (sliding, flipping and turning) to sink a golf ball into a cup. There are nine holes in the course and learners are challenged to meet or break a par score.

2011-01-01

248

Transformative copy  

E-print Network

The ability to create an unlimited number of identical copies is a privilege of digital documents. What if that would not be the case, if each copy of a digital file would go along with some sort of transformation? This ...

Offenhuber, Dietmar

2008-01-01

249

Transforming California  

NSDL National Science Digital Library

Transforming California is a PowerPoint presentation of digital images (60.7 Mb) exploring the landforms found along the San Andreas Fault. Designed for classroom use, this slideshow provides a complementing narrative for each slide.

Thomas McGuire

2001-01-01

250

Triple transformation  

NASA Astrophysics Data System (ADS)

A new business plan that enables policy transformation and resource mobilization at the national and international level, while improving access to resources, will allow the Green Climate Fund to integrate development goals and action on climate change.

Khan, Farrukh I.; Schinn, Dustin S.

2013-08-01

251

Cotton Transformation  

Microsoft Academic Search

Cotton has been cultured in vitro for 37 years, yet even today, some of the culture difficulties that were seen when it was\\u000a first cultured, namely, a very long culture time and a limited number of cultivars that can be cultured, continue to pose\\u000a problems. These inherent tissue culture limitations have made transforming cotton an arduous process. Transforming embryogenic\\u000a callus

D. R. Duncan

252

DNA Transformation  

NSDL National Science Digital Library

Stanley Cohen and Herbert Boyer's historic experiment used techniques to cut and paste DNA to create the first custom-made organism containing recombined or 'recombinant' DNA. Cohen and Boyer inserted the recombinant DNA molecule they created into E. coli bacteria by means of a plasmid, thereby inducing the uptake and expression of a foreign DNA sequence known as 'transformation.' This animation from Cold Spring Harbor Laboratory's Dolan DNA Learning Center presents DNA transformation through a series of illustrations of the processes involved.

253

FOURIER TRANSFORM INFRARED PHOTOACOUSTIC SPECTROSCOPY CHARACTERIZATION OF SULFUR-OXYGEN SPECIES RESULTING FROM THE REACTION OF SO2 WITH CAO AND CACO3  

EPA Science Inventory

Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) has been used to investigate the reaction of SO2 in He with CaO and CaCO3 particles at temperatures between 25 and 900 C. SO2 reacts with CaC at 25 C, while the reaction of Ca-CO3 with SO2 is first evident at 550 C ...

254

Isolation and Characterization of Human Intestinal Bacteria Capable of Transforming the Dietary Carcinogen 2-Amino-1-Methyl-6-Phenylimidazo[4,5-b]Pyridine?  

PubMed Central

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a carcinogenic heterocyclic aromatic amine formed in meat products during cooking. Although the formation of hazardous PhIP metabolites by mammalian enzymes has been extensively reported, research on the putative involvement of the human intestinal microbiota in PhIP metabolism remains scarce. In this study, the in vitro conversion of PhIP into its microbial derivate, 7-hydroxy-5-methyl-3-phenyl-6,7,8,9-tetrahydropyrido[3?,2?:4,5]imidazo[1,2-a]pyrimidin-5-ium chloride (PhIP-M1), by fecal samples from 18 human volunteers was investigated. High-performance liquid chromatography analysis showed that all human fecal samples transformed PhIP but with efficiencies ranging from 1.8 to 96% after 72 h of incubation. Two PhIP-transforming strains, PhIP-M1-a and PhIP-M1-b, were isolated from human feces and identified by fluorescent amplified fragment length polymorphism and pheS sequence analyses as Enterococcus faecium strains. Some strains from culture collections belonging to the species E. durans, E. avium, E. faecium, and Lactobacillus reuteri were also able to perform this transformation. Yeast extract, special peptone, and meat extract supported PhIP transformation by the enriched E. faecium strains, while tryptone, monomeric sugars, starch, and cellulose did not. Glycerol was identified as a fecal matrix constituent required for PhIP transformation. Abiotic synthesis of PhIP-M1 and quantification of the glycerol metabolite 3-hydroxypropionaldehyde (3-HPA) confirmed that the anaerobic fermentation of glycerol via 3-HPA is the critical bacterial transformation process responsible for the formation of PhIP-M1. Whether it is a detoxification is still a matter of debate, since PhIP-M1 has been shown to be cytotoxic toward Caco-2 cells but is not mutagenic in the Ames assay. PMID:18192423

Vanhaecke, Lynn; Vercruysse, Filip; Boon, Nico; Verstraete, Willy; Cleenwerck, Ilse; De Wachter, Marjan; De Vos, Paul; van de Wiele, Tom

2008-01-01

255

Transforming America's Energy Economy Transforming America's  

E-print Network

#12;Transforming America's Energy Economy Transforming America's Energy Economy This document #12;Transforming America's Energy Economy A. Introduction: A Call for Action B. Envisioning the Future.5 Energy Efficiency C. Charting the Path Forward 1 #12;Transforming America's Energy Economy

256

SPATIAL TRANSFORMATIONS 1 Running head: Spatial transformations  

E-print Network

SPATIAL TRANSFORMATIONS 1 Running head: Spatial transformations Multiple Systems for Spatial Imagery: Transformations of Objects and Bodies Jeffrey M. Zacks* and Barbara Tversky * Washington COGNITION & COMPUTATION #12;SPATIAL TRANSFORMATIONS 2 Abstract Problem-solving often requires imagining

Zacks, Jeffrey M.

257

Psychoanalytic transformations.  

PubMed

The author describes how Bion took Freud's conception of dreams as a form of thought and used it as the basis of his theory of transformations. Bion developed an expanded theory of 'dream thought', understood as a process of selection and transformation of sensory and emotional experiences. In this theory, the work of analysis is in turn conceived as a process not only of deciphering symbols, of revealing already existing unconscious meanings, but also of symbol production--of a process for generating thoughts and conferring meaning on experiences that have never been conscious and never been repressed because they have never been 'thought'. Analysis, in its specific operational sense, becomes a system of transformation whereby unconscious somatopsychic processes acquire the conditions for representability and become capable of translation into thoughts, words and interpretations. The rules of transformation applied by the patient in his representations and those applied by the analyst in his interpretations have the same importance for the analytic process as those described by Freud for the process of dreaming. The author discusses the broad categories of transformation adduced by Bion (rigid motion, projective, and in hallucinosis) and introduces some further distinctions within them. PMID:18055372

Riolo, Fernando

2007-12-01

258

Fourier Transform Pairs The Fourier transform transforms a function of  

E-print Network

Fourier Transform Pairs The Fourier transform transforms a function of time, f(t), into a function of frequency, F(s): F {f(t)}(s) = F(s) = Z - f(t)e- j2st dt. The inverse Fourier transform transforms a func. The inverse Fourier transform of the Fourier trans- form is the identity transform: f(t) = Z - Z - f()e- j2s

Masci, Frank

259

Vectors for cloning in cyanobacteria: Construction and characterization of two recombinant plasmids capable of transformation to Escherichia coli K12 and Anacystis nidulans R2  

Microsoft Academic Search

Two plasmids were constructed consisting of the E. coli vector pACYC184 and the cyanobacterial plasmid pUC1. These recombinants, designated pUC104 and pUC105, can be transformed to E. coli K12 as well as to the cyanobacterium Anacystis nidulans R2 and in both hosts they express their antibiotic markers. pUC104 and pUC105 differ with respect to the location and the orientation of

C. J. Kuhlemeier; W. E. Borrias; C. A. M. J. J. van den Hondel; G. A. van Arkel

1981-01-01

260

Isolation and Characterization of Three Streptococcus pneumoniae Transformation-Specific Loci by Use of a lacZ Reporter Insertion Vector  

Microsoft Academic Search

Although more than a dozen new proteins are produced when Streptococcus pneumoniae cells become com- petent for genetic transformation, only a few of the corresponding genes have been identified to date. To find genes responsible for the production of competence-specific proteins, a random lacZ transcriptional fusion library was constructed in S. pneumoniae by using the insertional lacZ reporter vector pEVP3.

EKATERINA V. PESTOVA; DONALD A. MORRISON

1998-01-01

261

The development of modulated, quasi-isothermal and ultraslow thermal methods as a means of characterizing the ? to ? indomethacin polymorphic transformation.  

PubMed

While polymorphism remains a key issue within the pharmaceutical and related industries, the understanding of the transformation process itself remains relatively poorly understood. In this study we use a combination of conventional and modulated temperature differential scanning calorimetry (MTDSC), quasi-isothermal MTDSC (Qi-MTDSC) and ultraslow heating rate MTDSC as a novel means of investigating the temperature-induced ? to ? transformation in indomethacin, using hot stage microscopy and variable temperature attenuated total reflectance FTIR spectroscopy as supportive techniques. In particular, we utilize the ability of MTDSC to measure subtle heat capacity changes through the transformation, we examine the use of Lissajous analysis of the modulated heating signal itself (both scanning and quasi-isothermal) and finally we investigate the use of ultraslow heating rates (down to 0.04 °C/min) so as to facilitate examination of the melt-crystallization process at a scanning rate whereby kinetic hindrance becomes negligible. Indomethacin was prepared in the metastable ? and stable ? forms using standard approaches. Samples were studied using conventional DSC, Qi-MTDSC (involving holding and modulating the sample at a series of incremental temperature steps) and ultraslow MTDSC. All studies were conducted using a Q-1000 MTDSC using crimped pans, following standard calibration procedures. Conventional DSC at 10 °C/min showed the expected single melting responses for the ? and ? forms, while MTDSC at slower rates indicated the presence of a melt-crystallization process. Quasi-isothermal studies allowed the heat capacity to be estimated as a function of time, while the associated Lissajous analysis demonstrated distortion of the elliptical response as a result of the kinetic events involved. Ultraslow heating resulted in superimposition of the melting and crystallization processes, resulting in a discrete thermal event that was enthalpically equivalent to the difference between the two processes. It is suggested that these combined thermal methods allow the conversion to be profiled in a manner which facilitates both kinetic and thermodynamic analysis of the transformation. PMID:22449179

Qi, Sheng; Craig, Duncan Q M

2012-05-01

262

An X-ray diffraction (XRD) and Fourier transform infrared spectroscopic (FT-IR) characterization of the speciation of arsenic (V) in Portland cement type-V  

Microsoft Academic Search

The speciation of As(V) bearing oxyanions (AsO43?) in cementitious environment has been investigated by X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR). The hydration of Portland cement type-V(OPC-V) was found to be retarded in presence of AsO43?, and the retardation was caused mainly by the formation of highly insoluble calcium arsenate on the surface of hydrating cement particles. Arsenate

M. Yousuf A. Mollah; Felix Lu; David L. Cocke

1998-01-01

263

Subsurface characterization of an oxidation-induced phase transformation and twinning in nickel-based superalloy exposed to oxy-combustion environments  

SciTech Connect

In the integration of oxy-fuel combustion to turbine power generation system, turbine alloys are exposed to high temperature and an atmosphere comprised of steam, CO{sub 2} and O{sub 2}. While surface and internal oxidation of the alloy takes place, the microstructure in the subsurface region also changes due to oxidation. In this study, bare metal coupons of Ni-base superalloys were exposed in oxy-fuel combustion environment for up to 1000 h and the oxidation-related microstructures were examined. Phase transformation occurred in the subsurface region in Ni-based superalloy and led to twinning. The transformation product phases were analyzed through thermodynamic equilibrium calculations and various electron microscopy techniques, including scanning electron microscopy (SEM), orientation imaging microscopy (OIM) and transmission electron microscopy (TEM). The mechanism by which the phase transformation and the formation of the microstructure occurred was also discussed. The possible effects of the product phases on the performance of the alloy in service were discussed.

Zhu, Jingxi; Holcomb, Gordon R.; Jablonski, Paul D.; Wise, Adam; Li, Jia; Laughlin, David E.; Sridhar, Seetharaman

2012-07-30

264

E1A + cHa-ras transformed rat embryo fibroblast cells are characterized by high and constitutive DNA binding activities of AP-1 dimers with significantly altered composition.  

PubMed

Transcription factors of the AP-1/ATF family, including c-Fos, c-Jun, and ATF-2, play an important role in the regulation of cell proliferation and differentiation, and changes in their levels and/or activities may contribute to oncogenesis. We analyzed the alterations of AP-1/ATF transcription factors upon immortalization and transformation in a panel of cell lines derived from rat embryo fibroblast (REF) cells. The tumorigenic E1A + cHa-ras cells are characterized by high and constitutive DNA binding activities of AP-1, in contrast to nontransformed cells and the E1A cells. The expression of c-fos and c-jun genes was affected differently by the oncogenic transformation. By using antibodies to c-Jun and c-Fos proteins in electrophoretic mobility shift assays (EMSA), we showed that E1A + cHa-ras transformants did not contain c-Fos under any condition of cell cultivation and growth factor stimulation, whereas c-Jun was constitutively upregulated. In the absence of c-fos gene expression, c-Fos protein appears to be replaced by proteins of Fos family (Fra-1) and ATF family (ATF-2 and ATFa). To determine the possible mechanisms of c-fos downregulation in E1A + cHa-ras transformants we have obtained populations of geneticin-resistant clones containing integrated reporter construct -711fos-CAT and its mutants in serum-responsive element (SRE) and cAMP-responsive element (CRE). Data obtained show that the mutations within the SRE lead to a manifold activation of fos-CAT expression. This allows to suggest that c-fos downregulation in E1A + cHa-ras transformants is provided by a negative control mediated through the SRE regulatory region. The profound differences in regulation and composition of transcription factors of the AP-1 family probably play a pivotal role in the transformation of REF cells by E1A and cHa-ras oncogenes. PMID:10543728

Pospelova, T V; Medvedev, A V; Kukushkin, A N; Svetlikova, S B; van der Eb, A J; Dorsman, J C; Pospelov, V A

1999-01-01

265

The Laplace Transform 1 Laplace transform and inverse transform  

E-print Network

The Laplace Transform Name: 1 Laplace transform and inverse transform Definition. Let f(t) be a function defined for t 0. Then the integral L {f(t)} = 0 e-st f(t)dt is said to be the Laplace transform of f provided the integral converges. Fill in the following Laplace transforms. L {tn } = L {eat } = L

Yengulalp, Lynne

266

Exploring Transformations  

NSDL National Science Digital Library

In this activity, students will explore transformations of an absolute value function. Step by step instructions guide students in using graphing calculators to examine the effect that stretching and translating has on the coordinates of the graph. Teacher notes and a worksheet are also included to aid in teaching this lesson.

2012-08-29

267

Transformation Time  

ERIC Educational Resources Information Center

The program for the march by librarians on America's capital for the American Library Association (ALA) conference is predictably loaded with lobbying, legislation, and DC tours. It also abounds with professional opportunity and reflects the impact of Leslie Burger, one of the most activist ALA presidents in recent history. Her "Transformation"…

Berry, John N., III

2007-01-01

268

Transformation & Metamorphosis  

ERIC Educational Resources Information Center

The sculptures of Canadian artist Brian Jungen are a great inspiration for a lesson on creating new forms. Jungen transforms found objects into unique creations without fully concealing their original form or purpose. Frank Stella's sculpture series, including "K.132,2007" made of stainless steel and spray paint, is another great example of…

Lott, Debra

2009-01-01

269

Molecular cloning and characterization of avian sarcoma virus UR2 and comparison of its transforming sequence with those of other avian sarcoma viruses.  

PubMed Central

Avian sarcoma virus UR2 and its associated helper virus, UR2AV , were molecularly cloned into lambda gtWES X lambda B by using unintegrated viral DNAs. One UR2 and several UR2AV clones were obtained. The UR2 DNA was subsequently cloned into pBR322. Both UR2 and UR2AV DNAs were tested for their biological activity by transfection onto chicken embryo fibroblasts. When cotransfected with UR2AV DNA, UR2 DNA was able to induce transformation of chicken embryo fibroblasts with a morphology similar to that of parental UR2 . UR2 -specific protein with kinase activity and UR2 -specific RNA were detected in the transfected cells. Transforming virus, UR2 ( UR2AV ), was produced from the doubly transfected cells. Five of the six UR2AV clones tested were also shown to be biologically active. The insert of the UR2 DNA clone is 3.4 kilobases in length and contains two copies of the long terminal repeat. Detailed restriction mapping showed that UR2 DNA shared with UR2AV DNA 0.8 kilobases of 5' sequence, including a portion of 5' gag, and 1.4 kilobases of 3' sequence, including a portion of 3' env. The UR2 transforming sequence, ros, is ca. 1.2 kilobases. No significant homology was found between v-ros and the conserved regions of v-src, v-yes, or v- abl . By contrast, a significant homology was found between v-ros and v-fps. The v-fps-related sequence was mapped within a 300-base-pair sequence in the middle of ros. Images PMID:6328022

Neckameyer, W S; Wang, L H

1984-01-01

270

Purification and characterization of NAD(P)H-dependent nitroreductase I from Klebsiella sp. C1 and enzymatic transformation of 2,4,6-trinitrotoluene  

Microsoft Academic Search

Three NAD(P)H-dependent nitroreductases that can transform 2,4,6-trinitrotoluene (TNT) by two reduction pathways were detected\\u000a in Klebsiella sp. C1. Among these enzymes, the protein with the highest reduction activity of TNT (nitroreductase I) was purified to homogeneity\\u000a using ion-exchange, hydrophobic interaction, and size exclusion chromatographies. Nitroreductase I has a molecular mass of\\u000a 27 kDa as determined by SDS-PAGE, and exhibits a broad

Hyoun-Young Kim; Hong-Gyu Song

2005-01-01

271

Recent advances in transformation optics  

NASA Astrophysics Data System (ADS)

Within the past a few years, transformation optics has emerged as a new research area, since it provides a general methodology and design tool for manipulating electromagnetic waves in a prescribed manner. Using transformation optics, researchers have demonstrated a host of striking phenomena and devices; many of which were only thought possible in science fiction. In this paper, we review the most recent advances in transformation optics. We focus on the theory, design, fabrication and characterization of transformation devices such as the carpet cloak, ``Janus'' lens and plasmonic cloak at optical frequencies, which allow routing light at the nanoscale. We also provide an outlook of the challenges and future directions in this fascinating area of transformation optics.

Liu, Yongmin; Zhang, Xiang

2012-08-01

272

Recent advances in transformation optics.  

PubMed

Within the past a few years, transformation optics has emerged as a new research area, since it provides a general methodology and design tool for manipulating electromagnetic waves in a prescribed manner. Using transformation optics, researchers have demonstrated a host of striking phenomena and devices; many of which were only thought possible in science fiction. In this paper, we review the most recent advances in transformation optics. We focus on the theory, design, fabrication and characterization of transformation devices such as the carpet cloak, "Janus" lens and plasmonic cloak at optical frequencies, which allow routing light at the nanoscale. We also provide an outlook of the challenges and future directions in this fascinating area of transformation optics. PMID:22847459

Liu, Yongmin; Zhang, Xiang

2012-09-01

273

Evaluate and characterize mechanisms controlling transport, fate, and effects of army smokes in the aerosol wind tunnel: Transport, transformations, fate, and terrestrial ecological effects of hexachloroethane obscurant smokes  

Microsoft Academic Search

The terrestrial transport, chemical fate, and ecological effects of hexachloroethane (HC) smoke were evaluated under controlled wind tunnel conditions. The primary objectives of this research program are to characterize and assess the impacts of smoke and obscurants on: (1) natural vegetation characteristic of US Army training sites in the United States; (2) physical and chemical properties of soils representative of

D. A. Cataldo; M. W. Ligotke; H. Jr. Bolton; R. J. Fellows; P. Van Voris; B. D. McVeety; Shu-mei W. Li; K. M. McFadden

2009-01-01

274

Polycyclic aromatic hydrocarbons (PAHs) in ambient aerosols from Beijing: characterization of low volatile PAHs by positive-ion atmospheric pressure photoionization (APPI) coupled with Fourier transform ion cyclotron resonance.  

PubMed

Aromatic fractions derived from aerosol samples were characterized by gas chromatography and mass spectrometry (GC-MS), high temperature simulated distillation (SIMDIS), and positive-ion atmospheric pressure photoionization (APPI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), respectively. It was found that about 27 wt % compounds in aromatic fractions could not be eluted from a GC column and some large molecule PAHs were neglected in GC-MS analysis. APPI FT-ICR MS was proven to be a powerful approach for characterizing the molecular composition of aromatics, especially for the large molecular species. An aromatic sample from Beijing urban aerosol was successfully characterized by APPI FT-ICR MS. Results showed that most abundant aromatic compounds in PM2.5 (particles with aerodynamic diameter ? 2.5 ?m) were highly condensed hydrocarbons with 4-8 aromatic rings and their homologues with very short alkyl chains. Furthermore, heteroatom-containing hydrocarbons were found as the significant components of the aromatic fractions: O1, O2, N1, and S1 class species with 10-28 DBEs (double bond equivalents) and 14-38 carbon numbers were identified by APPI FT-ICR MS. The heteroatom PAHs had similar DBEs and carbon number distribution as regular PAHs. PMID:24702199

Jiang, Bin; Liang, Yongmei; Xu, Chunming; Zhang, Jingyi; Hu, Miao; Shi, Quan

2014-05-01

275

Transformations Journal  

NSDL National Science Digital Library

Different forms of communication have always had a tendency to transform interactions and everyday life in ways that have surprised people from many different backgrounds. Academics have long been interested in such dynamic transformations, and this electronic journal represents one of the responses to such processes. As their site notes, this journal is "dedicated to the exploration of ideas, issues and debates emerging out of contemporary global culture." Visitors to the site can read the complete version of every issue on the site, and they will be pleased to find such intriguing titles as "Rethinking Regionality", "Accidental Environments", and "Fleeing the City". Interested parties can also consult the site to learn about the journal's editorial board, their calls for papers, submission guidelines, and related links.

276

RF transformer  

DOEpatents

There is provided an improved RF transformer having a single-turn secondary of cylindrical shape and a coiled encapsulated primary contained within the secondary. The coil is tapered so that the narrowest separation between the primary and the secondary is at one end of the coil. The encapsulated primary is removable from the secondary so that a variety of different capacity primaries can be utilized with one secondary.

Smith, James L. (Naperville, IL); Helenberg, Harold W. (Calumet City, IL); Kilsdonk, Dennis J. (Joliet, IL)

1979-01-01

277

Expression and Functional Characterization of the Agrobacterium VirB2 Amino Acid Substitution Variants in T-pilus Biogenesis, Virulence, and Transient Transformation Efficiency  

PubMed Central

Agrobacterium tumefaciens is a phytopathogenic bacterium that causes crown gall disease by transferring transferred DNA (T-DNA) into the plant genome. The translocation process is mediated by the type IV secretion system (T4SS) consisting of the VirD4 coupling protein and 11 VirB proteins (VirB1 to VirB11). All VirB proteins are required for the production of T-pilus, which consists of processed VirB2 (T-pilin) and VirB5 as major and minor subunits, respectively. VirB2 is an essential component of T4SS, but the roles of VirB2 and the assembled T-pilus in Agrobacterium virulence and the T-DNA transfer process remain unknown. Here, we generated 34 VirB2 amino acid substitution variants to study the functions of VirB2 involved in VirB2 stability, extracellular VirB2/T-pilus production and virulence of A. tumefaciens. From the capacity for extracellular VirB2 production (ExB2+ or ExB2?) and tumorigenesis on tomato stems (Vir+ or Vir?), the mutants could be classified into three groups: ExB2?/Vir?, ExB2?/Vir+, and ExB2+/Vir+. We also confirmed by electron microscopy that five ExB2?/Vir+ mutants exhibited a wild-type level of virulence with their deficiency in T-pilus formation. Interestingly, although the five T-pilus?/Vir+ uncoupling mutants retained a wild-type level of tumorigenesis efficiency on tomato stems and/or potato tuber discs, their transient transformation efficiency in Arabidopsis seedlings was highly attenuated. In conclusion, we have provided evidence for a role of T-pilus in Agrobacterium transformation process and have identified the domains and amino acid residues critical for VirB2 stability, T-pilus biogenesis, tumorigenesis, and transient transformation efficiency. PMID:24971727

Wu, Hung-Yi; Chen, Chao-Ying; Lai, Erh-Min

2014-01-01

278

Transformers Transformer device used to raise (for  

E-print Network

Transformers Transformer ­ device used to raise (for transmission) and lower (for use) the ac with different #s of turns #12;Transformers Alternating primary current induces alternating magnetic flux in iron dt d NV B PP -= dt d NV B SS -= S S P P N V N V = #12;Transformers Transformation of voltage

Bertulani, Carlos A. - Department of Physics and Astronomy, Texas A&M University

279

Transformative learning.  

PubMed

The whole point of teaching and training is to have the learners leave in some way different from how they came in-more skilled, more knowledgeable, more self-aware. Transformative learning refers to dramatic change, where the learner achieves a shift in perspective. This shift results from a critical examination of one's own assumptions, values, and beliefs, and of the foundations and expectations of the system in which one operates. Educators are in the change business, and educators focused on implementing psychiatric rehabilitation, recovery-oriented services, and person-centered planning are in the transformative learning business. The shift from a traditional medical model to a recovery perspective, the shift from "illness" to "disability" to "wellness," and the shift from risk prevention to promoting opportunities for growth all require "standing outside ourselves" and looking at a "stark and highlighted picture" of the all-too-common status quo of mental health services today. With the right approach, learners can be developed, encouraged, disrupted, and transformed. PMID:23276245

Nemec, Patricia B

2012-12-01

280

Characterization of Japanese color sticks by energy dispersive X-ray fluorescence, X-ray diffraction and Fourier transform infrared analysis  

NASA Astrophysics Data System (ADS)

This work comprises the use of energy dispersive X-ray fluorescence (EDXRF), X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) techniques for the study of the composition of twentieth century traditional Japanese color sticks. By using the combination of analytical techniques it was possible to obtain information on inorganic and organic pigments, binders and fillers present in the sticks. The colorant materials identified in the sticks were zinc and titanium white, chrome yellow, yellow and red ochre, vermillion, alizarin, indigo, Prussian and synthetic ultramarine blue. The results also showed that calcite and barite were used as inorganic mineral fillers while Arabic gum was the medium used. EDXRF offered great potential for such investigations since it allowed the identification of the elements present in the sample preserving its integrity. However, this information alone was not enough to clearly identify some of the materials in study and therefore it was necessary to use XRD and FTIR techniques.

Manso, M.; Valadas, S.; Pessanha, S.; Guilherme, A.; Queralt, I.; Candeias, A. E.; Carvalho, M. L.

2010-04-01

281

Macrophomate synthase: characterization, sequence, and expression in Escherichia coli of the novel enzyme catalyzing unusual multistep transformation of 2-pyrones to benzoates.  

PubMed

Macrophoma commelinae isolated from spots on leaves of Commelina communis has the ability to transform 5-acetyl-4-methoxy-6-methyl-2-pyrone (1) to 4-acetyl-3-methoxy-5-methylbenzoic acid (macrophomic acid, 2). This biotransformation includes the condensation of the 2-pyrone ring with a C3-unit precursor to form a substituted benzoic acid. We optimized conditions for induction of enzyme activity in M. commelinae, identified oxalacetate as a C3-unit precursor with cell extract, and purified the novel enzyme, macrophomate synthase. Oxalacetate inhibited the enzyme activity at a concentration higher than 5 mM, and magnesium chloride stimulated the enzyme activity. Kinetic analyses gave K(m) of 1.7 mM for 1 at 5 mM oxalacetate, K(m) of 1.2 mM for oxalacetate at 5 mM 1, and k(cat) of 0.46 s(-1) per subunit. Pyruvate was a weak substrate, with K(m) of 35.2 mM and k(cat) of 0.027 s(-1) at 5 mM 1. We cloned and sequenced a cDNA encoding the macrophomate synthase. The cDNA of 1,225 bp contained an open reading frame that encoded a polypeptide of 339 amino acid residues and 36,244 Da, the sequence of which showed no significant similarity with known proteins in a homology search with BLAST programs. Transformed E. coli cells carrying the cDNA encoding the mature protein of macrophomate synthase overproduced macrophomate synthase under the control of the T7 phage promoter induced by IPTG. The purified enzyme showed the same values of K(m) and optimum pH as the native macrophomate synthase. PMID:10731719

Watanabe, K; Oikawa, H; Yagi, K; Ohashi, S; Mie, T; Ichihara, A; Honma, M

2000-03-01

282

Characterization of Cancer Stem-Like Cells Derived from Mouse Induced Pluripotent Stem Cells Transformed by Tumor-Derived Extracellular Vesicles  

PubMed Central

Several studies have shown that cancer niche can perform an active role in the regulation of tumor cell maintenance and progression through extracellular vesicles-based intercellular communication. However, it has not been reported whether this vesicle-mediated communication affects the malignant transformation of normal stem cells/progenitors. We have previously reported that the conditioned medium derived from the mouse Lewis Lung Carcinoma (LLC) cell line can convert mouse induced pluripotent stem cells (miPSCs) into cancer stem cells (CSCs), indicating that normal stem cells when placed in an aberrant microenvironment can give rise to functionally active CSCs. Here, we focused on the contribution of tumor-derived extracellular vesicles (tEVs) that are secreted from LLC cells to induce the transformation of miPSCs into CSCs. We isolated tEVs from the conditioned medium of LLC cells, and then the differentiating miPSCs were exposed to tEVs for 4 weeks. The resultant tEV treated cells (miPS-LLCev) expressed Nanog and Oct3/4 proteins comparable to miPSCs. The frequency of sphere formation of the miPS-LLCev cells in suspension culture indicated that the self-renewal capacity of the miPS-LLCev cells was significant. When the miPS-LLCev cells were subcutaneously transplanted into Balb/c nude mice, malignant liposarcomas with extensive angiogenesis developed. miPS-LLCevPT and miPS-LLCevDT, the cells established from primary site and disseminated liposarcomas, respectively, showed their capacities to self-renew and differentiate into adipocytes and endothelial cells. Moreover, we confirmed the secondary liposarcoma development when these cells were transplanted. Taken together, these results indicate that miPS-LLCev cells possess CSC properties. Thus, our current study provides the first evidence that tEVs have the potential to induce CSC properties in normal tissue stem cells/progenitors. PMID:25057308

Yan, Ting; Mizutani, Akifumi; Chen, Ling; Takaki, Mai; Hiramoto, Yuki; Matsuda, Shuichi; Shigehiro, Tsukasa; Kasai, Tomonari; Kudoh, Takayuki; Murakami, Hiroshi; Masuda, Junko; Hendrix, Mary J. C.; Strizzi, Luigi; Salomon, David S.; Fu, Li; Seno, Masaharu

2014-01-01

283

Use of wavelet-packet transforms to develop an engineering model for multifractal characterization of mutation dynamics in pathological and nonpathological gene sequences  

NASA Astrophysics Data System (ADS)

This study uses dynamical analysis to examine in a quantitative fashion the information coding mechanism in DNA sequences. This exceeds the simple dichotomy of either modeling the mechanism by comparing DNA sequence walks as Fractal Brownian Motion (fbm) processes. The 2-D mappings of the DNA sequences for this research are from Iterated Function System (IFS) (Also known as the ``Chaos Game Representation'' (CGR)) mappings of the DNA sequences. This technique converts a 1-D sequence into a 2-D representation that preserves subsequence structure and provides a visual representation. The second step of this analysis involves the application of Wavelet Packet Transforms, a recently developed technique from the field of signal processing. A multi-fractal model is built by using wavelet transforms to estimate the Hurst exponent, H. The Hurst exponent is a non-parametric measurement of the dynamism of a system. This procedure is used to evaluate gene- coding events in the DNA sequence of cystic fibrosis mutations. The H exponent is calculated for various mutation sites in this gene. The results of this study indicate the presence of anti-persistent, random walks and persistent ``sub-periods'' in the sequence. This indicates the hypothesis of a multi-fractal model of DNA information encoding warrants further consideration. This work examines the model's behavior in both pathological (mutations) and non-pathological (healthy) base pair sequences of the cystic fibrosis gene. These mutations both natural and synthetic were introduced by computer manipulation of the original base pair text files. The results show that disease severity and system ``information dynamics'' correlate. These results have implications for genetic engineering as well as in mathematical biology. They suggest that there is scope for more multi-fractal models to be developed.

Walker, David Lee

1999-12-01

284

An integrated approach to characterization of microbial exudates and investigation of their role in the spatial distribution and transformations of uranium at the mineral-microbe interface  

SciTech Connect

The long-term aim of this project was to understand the role of microbiota and their polymers (EPS) in controlling the distribution and fates of contaminants in subsurface environments. Additionally, this project also focused on the identification and characterization of extracellular proteins under a variety of growth conditions. Finally, this project sought to develop and advance the use of a variety of synchrotron-based hard-x-ray techniques to address a number of different ERSP elements.

Kemner, K.M.; O'Loughlin, E.J.; Kelly, S.D.; Nealson, K.H.

2006-06-01

285

Hamlet's Transformation.  

NASA Astrophysics Data System (ADS)

William Shakespeare's Hamlet has much evidence to suggest that the Bard was aware of the cosmological models of his time, specifically the geocentric bounded Ptolemaic and Tychonic models, and the infinite Diggesian. Moreover, Shakespeare describes how the Ptolemaic model is to be transformed to the Diggesian. Hamlet's "transformation" is the reason that Claudius, who personifies the Ptolemaic model, summons Rosencrantz and Guildenstern, who personify the Tychonic. Pantometria, written by Leonard Digges and his son Thomas in 1571, contains the first technical use of the word "transformation." At age thirty, Thomas Digges went on to propose his Perfit Description, as alluded to in Act Five where Hamlet's age is given as thirty. In Act Five as well, the words "bore" and "arms" refer to Thomas' vocation as muster-master and his scientific interest in ballistics. England's leading astronomer was also the father of the poet whose encomium introduced the First Folio of 1623. His oldest child Dudley became a member of the Virginia Company and facilitated the writing of The Tempest. Taken as a whole, such manifold connections to Thomas Digges support Hotson's contention that Shakespeare knew the Digges family. Rosencrantz and Guildenstern in Hamlet bear Danish names because they personify the Danish model, while the king's name is latinized like that of Claudius Ptolemaeus. The reason Shakespeare anglicized "Amleth" to "Hamlet" was because he saw a parallel between Book Three of Saxo Grammaticus and the eventual triumph of the Diggesian model. But Shakespeare eschewed Book Four, creating this particular ending from an infinity of other possibilities because it "suited his purpose," viz. to celebrate the concept of a boundless universe of stars like the Sun.

Usher, P. D.

1997-12-01

286

Rotary Transformer  

NASA Technical Reports Server (NTRS)

None given. From first Par: Many spacecraft (S/C) and surface rovers require the transfer of signals and power across rotating interfaces. Science instruments, antennas and solar arrays are elements needing rotary power transfer for certain (S/C) configurations. Delivery of signal and power has mainly been done by using the simplest means, the slip ring approach. This approach, although simple, leaves debris generating noise over a period of time...The rotary transformer is a good alternative to slip rings for signal and power transfer.

McLyman, Colonel Wm. T.

1996-01-01

287

Production and characterization of WEG-1, an epidermal growth factor/transforming growth factor-alpha-responsive mouse uterine epithelial cell line.  

PubMed

Uterine epithelial cells (UEC) isolated from 6-week-old CF-1 mice were immortalized using retroviral-mediated transfection of SV40 large T-antigen. One line, WEG-1, retained epithelial morphology and reacted with antibodies to cytokeratins 18, 19, laminin, fibronectin, and beta-catenin. In addition, WEG-1 cells displayed strong nuclear immunoreactivity to SV40 large T-antigen, confirming integration of the retrovirus vector and expression of this gene. WEG-1 cells were negative for nonepithelial markers such as desmin and factor 8. WEG-1 cells did not proliferate in serum-free medium; however, addition of 0.5% FBS supported proliferation to the same extent as 10% FBS. Addition of 50 ng/ml epidermal growth factor to medium containing 0.5% charcoal-stripped FBS restored proliferation comparable with 0.5% whole FBS. Epidermal growth factor or transforming growth factor-alpha (50 ng/ml), but not transforming growth factor-beta, leukemia-inhibiting factor, or fibroblast growth factor, induced the secretion of three proteins (M(r) approximately to 158K, 148K, and 36K). Comparison of protein secretions of WEG-1 cells and UEC showed shared as well as distinct bands. Like UEC, WEG-1 cells secreted PGF2a and PGE2 and expressed PG GH synthase-2. Unlike UEC, WEG-1 cells showed no apical/basal preference for either uptake of methionine or secretion of proteins. The absence of immunoreactive E-cadherin or zona occludens-1 was consistent with the absence of cell polarity in WEG-1 cells. Primary UEC, which polarize in vitro, do not support blastocyst attachment. WEG-1 cells, although not polarized in vitro, also exhibited delayed blastocyst attachment compared with nonuterine cell lines, suggesting that WEG-1 cells partially retained some aspects of UEC function relevant to embryo attachment. WEG-1 cells expressed messenger RNA for Muc-1, an UEC mucin suggested to have antiadhesive properties. Furthermore, WEG-1 cells did not display high affinity heparin binding sites, an activity associated with embryo attachment. WEG-1 cells may provide a model for studying various aspects of UEC function and murine embryo attachment. PMID:8536610

Wegner, C C; Cherington, V; Clemens, J W; Jacobs, A L; Julian, J; Surveyor, G A; Bell, E C; Carson, D D

1996-01-01

288

Identification and Characterization of a Ginsenoside-Transforming ?-Glucosidase from Pseudonocardia sp. Gsoil 1536 and Its Application for Enhanced Production of Minor Ginsenoside Rg2(S)  

PubMed Central

The ginsenoside Rg2(S), which is one of the pharmaceutical components of ginseng, is known to have neuroprotective, anti-inflammation, and anti-diabetic effects. However, the usage of ginsenoside Rg2(S) is restricted owing to the small amounts found in white and red ginseng. To enhance the production of ginsenoside Rg2(S) as a 100 gram unit with high specificity, yield, and purity, an enzymatic bioconversion method was developed to adopt the recombinant glycoside hydrolase (BglPC28), which is a ginsenoside-transforming recombinant ?-glucosidase from Pseudonocardia sp. strain Gsoil 1536. The gene, termed bglPC28, encoding ?-glucosidase (BglPC28) belonging to the glycoside hydrolase family 3 was cloned. bglPC28 consists of 2,232 bp (743 amino acid residues) with a predicted molecular mass of 78,975 Da. This enzyme was overexpressed in Escherichia coli BL21(DE3) using a GST-fused pGEX 4T-1 vector system. The optimum conditions of the recombinant BglPC28 were pH 7.0 and 37°C. BglPC28 can effectively transform the ginsenoside Re to Rg2(S); the Km values of PNPG and Re were 6.36±1.10 and 1.42±0.13 mM, respectively, and the Vmax values were 40.0±2.55 and 5.62±0.21 µmol min?1 mg?1 of protein, respectively. A scaled-up biotransformation reaction was performed in a 10 L jar fermenter at pH 7.0 and 30°C for 12 hours with a concentration of 20 mg/ml of ginsenoside Re from American ginseng roots. Finally, 113 g of Rg2(S) was produced from 150 g of Re with 84.0±1.1% chromatographic purity. These results suggest that this enzymatic method could be usefully exploited in the preparation of ginsenoside Rg2(S) in the cosmetics, functional food, and pharmaceutical industries. PMID:24911166

Park, Sung Chul; Kim, Jin-Kwang; Yu, Hong-Shan; Jin, Feng-Xie; Sun, Changkai; Kim, Sun-Chang; Im, Wan-Taek

2014-01-01

289

Characterization of CZTSSe photovoltaic device with an atomic layer-deposited passivation layer  

SciTech Connect

We describe a CZTSSe (Cu{sub 2}ZnSn(S{sub 1?x},Se{sub x}){sub 4}) photovoltaic (PV) device with an ALD (atomic layer deposition) coated buffer dielectric layer for CZTSSe surface passivation. An ALD buffer layer, such as TiO{sub 2}, can be applied in order to reduce the interface recombination and improve the device's open-circuit voltage. Detailed characterization data including current-voltage, admittance spectroscopy, and capacitance profiling are presented in order to compare the performance of PV devices with and without the ALD layer.

Wu, Wei, E-mail: wei.wu@dupont.com; Cao, Yanyan; Caspar, Jonathan V.; Guo, Qijie; Johnson, Lynda K.; Mclean, Robert S.; Malajovich, Irina; Choudhury, Kaushik Roy [DuPont Central Research and Development, Wilmington, Delaware 19880 (United States)

2014-07-28

290

Characterization of EBV-genome negative "null" and "T" cell lines derived from children with acute lymphoblastic leukemia and leukemic transformed non-Hodgkin lymphoma.  

PubMed

Sixty-two explants from peripheral blood, bone marrow and cerebral fluid of children with acute lymphoblastic leukemia (ALL) and leukemic transformed non-Hodgkin lymphoma (NHL) were cultivated for at least 8 weeks. Although lymphatic cells persisted up to 16 weeks in tissue culture, no proliferation was observed in 54 cultures. From the remaining cultures, eight permanently growing cell lines were obtained. Five of these were EBNA (Epstein-Barr virus-specific nuclear antigen)-positive. Three, however, were ENBA-negative and lacked Epstein-Barr virus genomes. Two cell lines (KM-3 and SH-2) expressed neither B nor T cell characteristics. One line (JM) expressed T cell characteristics and complement receptors. The growing lymphatic cells represented leukemic cells, since the pattern of cytochemical staining and that of membrane receptors of lymphoblasts from the same donor prior to cultivation were identical. All leukemic cell lines were derived from patients in relapse. In contrast, no proliferation of leukemic cells occurred in explains from patients revealing the first manifestation of the disease. These results suggest enhanced growth potential of lymphoblasts resisting antileukemic therapy. PMID:68013

Schneider, U; Schwenk, H U; Bornkamm, G

1977-05-15

291

Regular Combinators for String Transformations  

E-print Network

for such functions has been defined using two-way finite-state transducers, (one-way) cost register automata, and MSO-definable graph transformations. In this paper, we give an algebraic and machine-independent characterization of finite-state automata and the associated theory of regular languages, a natural starting point

Plotkin, Joshua B.

292

Evaluate and characterize mechanisms controlling transport, fate, and effects of army smokes in the aerosol wind tunnel: Transport, transformations, fate, and terrestrial ecological effects of hexachloroethane obscurant smokes  

SciTech Connect

The terrestrial transport, chemical fate, and ecological effects of hexachloroethane (HC) smoke were evaluated under controlled wind tunnel conditions. The primary objectives of this research program are to characterize and assess the impacts of smoke and obscurants on: (1) natural vegetation characteristic of US Army training sites in the United States; (2) physical and chemical properties of soils representative of these training sites; and (3) soil microbiological and invertebrate communities. Impacts and dose/responses were evaluated based on exposure scenarios, including exposure duration, exposure rate, and sequential cumulative dosing. Key to understanding the environmental impacts of HC smoke/obscurants is establishing the importance of environmental parameters such as relative humidity and wind speed on airborne aerosol characteristics and deposition to receptor surfaces. Direct and indirect biotic effects were evaluated using five plant species and two soil types. HC aerosols were generated in a controlled atmosphere wind tunnel by combustion of hexachloroethane mixtures prepared to simulate normal pot burn rates and conditions. The aerosol was characterized and used to expose plant, soil, and other test systems. Particle sizes of airborne HC ranged from 1.3 to 2.1 {mu}m mass median aerodynamic diameter (MMAD), and particle size was affected by relative humidity over a range of 20% to 85%. Air concentrations employed ranged from 130 to 680 mg/m{sup 3}, depending on exposure scenario. Chlorocarbon concentrations within smokes, deposition rates for plant and soil surfaces, and persistence were determined. The fate of principal inorganic species (Zn, Al, and Cl) in a range of soils was assessed.

Cataldo, D.A.; Ligotke, M.W.; Bolton, H. Jr.; Fellows, R.J.; Van Voris, P.; McVeety, B.D.; Li, Shu-mei W.; McFadden, K.M.

1989-09-01

293

Testability Transformation: Program Transformation to Improve Testability  

E-print Network

Testability Transformation: Program Transformation to Improve Testability An Overview of Recent Author. Abstract. Testability transformation is a new form of program transfor- mation in which the goal to some chosen test adequacy criterion. The goal is to improve the testing process by transforming

Singer, Jeremy

294

Testability Transformation --Program Transformation to Improve Testability  

E-print Network

Testability Transformation -- Program Transformation to Improve Testability Mark Harman1 , Andr, 26 Richmond Street, Glasgow G1 1XH, UK. Corresponding Author. Abstract. Testability transformation. The goal is to improve the testing process by transforming a program to one that is more amenable

Binkley, David W.

295

Enterprise transformation :lessons learned, pathways to success.  

SciTech Connect

In this report, we characterize the key themes of transformation and tie them together in a ''how to'' guide. The perspectives were synthesized from strategic management literature, case studies, and from interviews with key management personnel from private industry on their transformation experiences.

Slavin, Adam M.; Woodard, Joan Brune

2006-05-01

296

Natural and anthropogenic impacts on biogeochemical cycle in Yangtze River basin: Source, transformation and fate of dissolved organic matter (DOM) characterized by 3-D fluorescence spectroscopy  

NASA Astrophysics Data System (ADS)

Inland waters play an important role in the global carbon cycle as reactors for DOM cycling, transformation and transportation. With large amounts of terrestrial DOM, the Yangtze River is vital for coastal environment and ecosystem. In the context of climate change, it's critical to evaluate both hydrodynamic conditions and increasing human activities' impacts on biogeochemical cycle of DOM in Yangtze River across different climatic and hydrologic regions which are poorly understood. What's more, the hydrologic condition changes caused by the Three Gorges Dam (TGD, world's largest power station in terms of installed capacity) have recently proven to be a partition factor for fluvial particle. However, it's still an enigma for dissolved matter cycle. To address those issues, this study applies EEMs combined with bulk characteristics, chlorophyll and absorption spectrum in an attempt to assess characteristics and dynamics of DOM in Yangtze River. It's a novel optical approach that could 'see' molecular structure of DOM without the limits of time-consuming and laborious molecular measurements. Combined with parallel factor analysis, 5 individual fluorescent components have been identified: 3 humic-like (H1, H2, H3) and 2 protein-like components (P1, P2). With typical bioavailability and photo-reactivity, these components suggest different sources and dynamics. On the whole, both DOC and the sum of all 5 components (? Fluo) increased remarkably from the upper reach especially to the Three Gorge Dam and thereafter remained constant (R2between DOC and - Fluo: 0.92). The protein-like components (- P) accounted for 1/4 of - Fluo with apparently weak correlations with DOC and chlorophyll, which implied that the DOM is not dominated by autochthonous production, especially for the upper reach with high concentration of total suspended matter. As for Humic-like component, increasing H1 and DOC in the TGD reservoir area implied impacts from human activities there with intercept of sewage rather than an enabling environment for degradation. While in the lower reach where H3(Ex/Em:250/450~485nm) was accumulated, the other components (H1, H2) and a350 (absorption coefficient at 350nm) seemed to be degraded faster than H3 indicating that DOM might be subjected to selective biological and photochemical degradation processes, combined with remarkably higher Sr (absorption coefficient slope ratio, indicator of the degradation degree and aromatic property) in the lower reach after TGD, these facts suggests that the contrasting hydrology before and after TGD has led to a more significant composition differences and selective degradation of DOM. In case of any biased views, we conducted both dark and light incubations which showed consistency with the conclusion above. Besides, a comparison of Yangtze River and the other large rivers shows that the EEMs and a350 vary with land use, latitude and human activities, which verified their potential to trace the source and fate of fluvial DOM, even for different regions and water masses. Such knowledge on compositional differences of DOM resulting from variations in DOM sources and local environmental conditions (different photo-/bio-reactivity associated re-mineralization potential) during fluvial transport, would undoubtedly assist in predicting the consequences of global change and its relationship to global carbon cycling.

Gan, Shuchai; Wu, Ying; Bao, Hongyan; Zhang, Jing

2013-04-01

297

Random fractional Fourier transform.  

PubMed

We propose a novel random fractional Fourier transform by randomizing the transform kernel function of the conventional fractional Fourier transform. The random fractional Fourier transform inherits the excellent mathematical properties from the fractional Fourier transform and can be easily implemented in optics. As a primary application the random fractional Fourier transform can be directly used in optical image encryption and decryption. The double phase encoding image encryption schemes can thus be modeled with cascaded random fractional Fourier transformers. PMID:17671545

Liu, Zhengjun; Liu, Shutian

2007-08-01

298

Quantum transformations  

SciTech Connect

We show that the quantum Hamilton-Jacobi equation can be written in the classical form with the spatial derivative {partial_derivative}{sub q} replaced by {partial_derivative}{sub q} with dq = dq/{radical}1{minus}{beta}{sup 2}(q), where {beta}{sup 2}(q) is strictly related to the quantum potential. This can be seen as the opposite of the problem of finding the wave function representation of classical mechanics as formulated by Schiller and Rosen. The structure of the above {open_quotes}quantum transformation{close_quotes}, related to the recently formulated equivalence principle, indicates that the potential deforms space geometry. In particular, a result by Flanders implies that both W(q) = V(q) {minus} E and the quantum potential Q are proportional to the curvatures {kappa}{sub W} and {kappa}{sub Q} which arise as natural invariants in an equivalence problem for curves in the projective line. In this formulation the Schroedinger equation takes the geometrical form ({partial_derivative}{sub q}{sup 2} + {kappa}{sub W}){psi} = 0.

Faraggi, A.E. [Univ. of Florida, Gainesville, FL (United States). Institute for Fundamental Theory; Matone, M. [Univ. of Padova (Italy). Dept. of Physics G. Galilei

1998-01-09

299

Canonoid and Poissonoid Transformations, Symmetries and BiHamiltonian Structures  

E-print Network

We give a characterization of linear canonoid transformations on symplectic manifolds and we use it to generate biHamiltonian structures for some mechanical systems. Utilizing this characterization we also study the behavior of the harmonic oscillator under canonoid transformations. We present a description of canonoid transformations due to E.T. Whittaker, and we show that it leads, in a natural way, to the modern, coordinate-independent definition of canonoid transformations. We also generalize canonoid transformations to Poisson manifolds by introducing Poissonoid transformations. We give examples of such transformations for Euler's equations of the rigid body (on $\\mathcal{so}^\\ast (3) $ and $ so^\\ast (4)$) and for an integrable case of Kirchhoff's equations for the motion of a rigid body immersed in an ideal fluid. We study the relationship between biHamiltonian structures and Poissonoid transformations for these examples. We analyze the link between Poissonoid transformations, constants of motion, and symmetries.

Giovanni Rastelli; Manuele Santoprete

2015-02-25

300

Efficiency of Deterministic Entanglement Transformation  

E-print Network

We prove that sufficiently many copies of a bipartite entangled pure state can always be transformed into some copies of another one with certainty by local quantum operations and classical communication. The efficiency of such a transformation is characterized by deterministic entanglement exchange rate, and it is proved to be always positive and bounded from top by the infimum of the ratios of Renyi's entropies of source state and target state. A careful analysis shows that the deterministic entanglement exchange rate cannot be increased even in the presence of catalysts. As an application, we show that there can be two incomparable states with deterministic entanglement exchange rate strictly exceeding 1.

Runyao Duan; Yuan Feng; Zhengfeng Ji; Mingsheng Ying

2005-02-11

301

Transforming giants.  

PubMed

Large corporations have long been seen as lumbering, inflexible, bureaucratic--and clueless about global developments. But recently some multinationals seem to be transforming themselves: They're engaging employees, moving quickly, and introducing innovations that show true connection with the world. Harvard Business School's Kanter ventured with a research team inside a dozen global giants--including IBM, Procter & Gamble, Omron, CEMEX, Cisco, and Banco Real--to discover what has been driving the change. After conducting more than 350 interviews on five continents, she and her colleagues came away with a strong sense that we are witnessing the dawn of a new model of corporate power: The coordination of actions and decisions on the front lines now appears to stem from widely shared values and a sturdy platform of common processes and technology, not from top-down decrees. In particular, the values that engage the passions of far-flung workforces stress openness, inclusion, and making the world a better place. Through this shift in what might be called their guidance systems, the companies have become as creative and nimble as much smaller ones, even while taking on social and environmental challenges of a scale that only large enterprises could attempt. IBM, for instance, has created a nonprofit partnership, World Community Grid, through which any organization or individual can donate unused computing power to research projects and see what is being done with the donation in real time. IBM has gained an inspiring showcase for its new technology, helped business partners connect with the company in a positive way, and offered individuals all over the globe the chance to contribute to something big. PMID:18271317

Kanter, Rosabeth Moss

2008-01-01

302

Parameterized Transformation Units  

Microsoft Academic Search

Transformation units are a structuring principle for graph transformation systems. They consist of a set of graph transformation rules, descriptions of initial and terminal graphs, a control condition, and a set of imported transformation units. Semantically, they transform initial graphs to terminal ones by interleaving rule applications with calls to imported units in such a way that the control condition

Sabine Kuske

2002-01-01

303

Analyzing Signals Fourier transform  

E-print Network

Page 1 1 Analyzing Signals Fourier transform s frequency content s linear combination of sin frequency analysis s windowed Fourier transform 6 #12;Page 4 7 Gabor Transform function to analyze window Gabor Transform Spatial domain Gabor domain b #12;Page 5 9 Gabor Transform Problems s discrete version

Sweldens, Wim

304

Structural characterization and physical properties of P2O5-CaO-Na2O-TiO2 glasses by Fourier transform infrared, Raman and solid-state magic angle spinning nuclear magnetic resonance spectroscopies.  

PubMed

Phosphate-based glasses have been investigated for tissue engineering applications. This study details the properties and structural characterization of titanium ultra-phosphate glasses in the 55(P(2)O(5))-30(CaO)-(25-x)(Na(2)O)-x(TiO(2)) (0?x?5) system, which have been prepared via melt-quenching techniques. Structural characterization was achieved by a combination of X-ray diffraction (XRD), and solid-state nuclear magnetic resonance, Raman and Fourier transform infrared spectroscopies. Physical properties were also investigated using density, degradation and ion release studies; additionally, differential thermal analysis was used for thermal analysis of these glasses. The results show that with the addition of TiO(2) the density and glass transition temperature increased whereas the degradation and ion release properties are decreased. From XRD data, TiP(2)O(7) and CaP(2)O(6) were detected in 3 and 5 mol.% TiO(2)-containing glasses. Magic angle spinning nuclear magnetic resonance results confirmed that as TiO(2) is incorporated into the glass; the amount of Q(3) increases as the amount of Q(2) consequently decreases, indicating increasing polymerization of the phosphate network. Spectroscopy results also showed that the local structure of glasses changes with increasing TiO(2) content. As TiO(2) is incorporated into the glass, the phosphate connectivity increases, indicating that the addition of TiO(2) content correlates unequivocally with an increase in glass stability. PMID:21930253

Kiani, Azadeh; Hanna, John V; King, Scott P; Rees, Gregory J; Smith, Mark E; Roohpour, Nima; Salih, Vehid; Knowles, Jonathan C

2012-01-01

305

Molecular characterization of a thyroid tumor-specific transforming sequence formed by the fusion of ret tyrosine kinase and the regulatory subunit RI alpha of cyclic AMP-dependent protein kinase A.  

PubMed Central

The ret oncogene frequently has been found activated in papillary thyroid carcinomas. A previous characterization of ret activation revealed recombination of its tyrosine kinase domain and sequences derived from an uncharacterized locus (D10S170). The mechanism leading to this recombination was identified as a paracentric inversion of the long arm of chromosome 10, inv(10)(q11.2q21), with the breakpoints occurring where ret and D10S170 were mapped. To further characterize the activation of ret in papillary thyroid carcinomas, we have now isolated and sequenced a second type of ret oncogenic rearrangement not involving the D10S170 locus. The nucleotide sequence indicated that the transforming activity was created by the fusion of the ret tyrosine kinase domain with part of the RI alpha regulatory subunit of protein kinase A (PKA). This is the first example of an oncogenic activity involving a PKA gene. PKA is the main intracellular cyclic AMP receptor, and its RI alpha subunit gene is located on chromosome 17q. RI alpha-ret transcripts encode two isoforms of the chimeric protein (p76 and p81), which display constitutive tyrosine phosphorylation as well as a tyrosine kinase enzymatic activity. Under nonreducing conditions, both isoforms are found in a dimeric configuration because of both homo- and heterodimer formation. Thus, the in vivo activation of ret in human papillary thyroid carcinomas is provided by the fusion of its tyrosine kinase domain with different genes and can be mediated by different mechanisms of gene rearrangement. Images PMID:7678053

Bongarzone, I; Monzini, N; Borrello, M G; Carcano, C; Ferraresi, G; Arighi, E; Mondellini, P; Della Porta, G; Pierotti, M A

1993-01-01

306

Characterization of triplex RNA poly[rU]· poly[rA]· poly[rU] adsorbed on silver colloids by Fourier transform surface enhanced Raman scattering and scanning tunneling microscopy  

NASA Astrophysics Data System (ADS)

Fourier transform surface enhanced Raman scattering (SERS) spectroscopy has been used to characterize triplex RNA poly[rU] · poly[rA] · poly[rU] adsorbed on silver colloid using an Nd:YAG laser as an excitation source. In this case, SERS spectra of high quality are recordable in a relatively short time. Compared to the FT-Raman spectrum of the triplex in solid, two distinct SERS bands centered at 835 and 819 cm -1 indicate that the helical structure of the triplex RNA in the proximity of the colloidal silver surfaces is well preserved. From UV-vis spectroscopy, the aggregation state of original silver colloids might not be distinctly altered after the triplex RNA was added up to 1 × 10 -5 M. Moreover, scanning tunneling microscopy (STM) observations of the triplex-silver colloid complex also clearly reveal that the aggregation state of the silver colloids is changed from original dispersed particles to predominantly ordered adsorption along the phosphate backbone of the triplex with some aggregation, indicating that the microstructural changes of the silver surfaces play an important role in the SERS effect.

Fang, Ye; Bai, Chunli; Wang, Ting; Tang, You-Qi

1995-08-01

307

GIS TRANSFORMATIONS Conference Presentation  

E-print Network

GIS TRANSFORMATIONS Conference Presentation Waldo Tobler Geography Department University, line, area, or field phenomena, then the sixteen common classes of transformation are: point -> point (scalar, vector, tensor) data, to obtain eighty distinct possible classes of transformation. The common

Tobler, Waldo

308

Transforming DNA Uptake Gene Orthologs Do Not Mediate Spontaneous Plasmid Transformation in Escherichia coli  

Microsoft Academic Search

Spontaneous plasmid transformation of Escherichia coli occurs on nutrient-containing agar plates. E. coli has also been reported to use double-stranded DNA (dsDNA) as a carbon source. The mechanism(s) of entry of exogenous dsDNA that allows plasmid establishment or the use of DNA as a nutrient remain(s) unknown. To further characterize plasmid transformation, we first documented the stimulation of transformation by

Dongchang Sun; Xuewu Zhang; Lingyu Wang; Marc Prudhomme; Zhixiong Xie; Bernard Martin; Jean-Pierre Claverys

2009-01-01

309

Phase Transformations in Confined Nanosystems  

SciTech Connect

This project discovered that non-equilibrium structures, including chemically ordered structures not observed in bulk systems, form in isolated nanoscale systems. Further, a generalized model was developed that effectively explained the suppression of equilibrium phase transformations. This thermodynamic model considered the free energy decrease associated with the phase transformation was less than the increase in energy associated with the formation of an interphase interface, therefore inhibiting the phase transformation. A critical diameter exists where the system transitions to bulk behavior, and a generalized equation was formulated that successfully predicted this transition in the Fe-Au system. This provided and explains a new route to novel structures not possible in bulk systems. The structural characterization was accomplished using transmission electron microscopy in collaboration with Matthew Kramer of Ames Laboratory. The PI and graduate student visited Ames Laboratory several times a year to conduct the experiments.

Shield, Jeffrey E. [Department of Mechanical & Materials Engineering] [Department of Mechanical & Materials Engineering; Belashchenko, Kirill [Department of Physics & Astronomy] [Department of Physics & Astronomy

2014-04-29

310

Bovine papillomavirus contains multiple transforming genes.  

PubMed Central

Bovine papillomavirus type 1 (BPV-1) and its cloned full-length DNA can transform rodent cells in vitro, and the viral DNA persists as an extrachromosomal multicopy plasmid in these transformed cells. Previous studies have identified at least five discrete viral RNAs that are expressed in BPV-1 transformed cells and have shown that these transcripts share a 3' coterminus. To further define the structure of these RNAs and to characterize the functions of individual viral transcripts, we constructed a cDNA library with mRNA from BPV-1-transformed mouse C127 cells using an Okayama and Berg plasmid. From a library of 10(5) independent clones, 200 BPV-1 specific clones were isolated and characterized. Sequence analysis has revealed differential splicing patterns for the mRNA species in BPV-1 transformed cells. In conjunction with the open reading frames (ORFs) deduced from the BPV-1 DNA sequence, it is possible to predict the structure of the potential encoded proteins. The vector used to generate these cDNA clones contains mammalian cell transcriptional regulatory elements, facilitating their functional characterization. We have identified two distinct classes of cDNA clones that can each independently transform mouse C127 cells. One class of cDNA clones contains the E2 ORF intact and the second contains the E6 ORF intact. These two putative viral functions appear to act synergistically in transforming mouse C127 cells in vitro. PMID:2983327

Yang, Y C; Okayama, H; Howley, P M

1985-01-01

311

Transforms in Statistics  

Microsoft Academic Search

It is not an overstatement to say that statistics is based on various transformations of data. Basic statistical summaries such as the sample mean, variance, z-scores, histograms, etc., are all transformed data. Some more advanced summaries, such as principal components, periodograms, empirical characteristic functions, etc., are also examples of transformed data. To give a just coverage of transforms utilized in

Brani Vidakovic

2004-01-01

312

Glowing Bacteria: Transformation Efficiency  

E-print Network

1 Glowing Bacteria: Transformation Efficiency Purpose: To determine how well your E. coli cells took up and expressed GFP after transformation. Background: Transformation efficiency is a quantitative)______ (Fraction of DNA spread on plate) = ______ µg plasmid DNA spread on plate #12;2 5. Transformation efficiency

Rose, Michael R.

313

transformation languages Introduction  

E-print Network

transformation languages Introduction Transformation languages are widely used for to process can I change / transform the design of a certain task without changing it's logic The common/and hierarchical or/and abstract set of information. It can even be a stream of data. · The transformation engine

Nierstrasz, Oscar

314

RM2: Transform operations  

NASA Technical Reports Server (NTRS)

The two-dimensional transform used in the research TV source encoder, RM2 is discussed. It is shown that both conceptually and in terms of the number of required computations, the RM2 transform is considerably simpler than the Fast Hadamard Transform. The latter can in fact be generated by extending the RM2 transform.

Rice, R. F.

1974-01-01

315

LAPPED TRANSFORMS COMPRESSION  

E-print Network

the basic notation, give a brief history of lapped transforms and introduce block-based transforms. We) vector while A represents a matrix. 6.1.2 Brief history In the early 80's, transform coding was maturing extensively studied mainly because lapped transforms are closely related to filter banks, wavelets, and time

de Queiroz, Ricardo L.

316

Fast Discrete Curvelet Transforms  

Microsoft Academic Search

This paper describes two digital implementations of a new mathematical transform, namely, the second generation curvelet transform (12, 10) in two and three dimensions. The first digital transformation is based on unequally-spaced fast Fourier transforms (USFFT) while the second is based on the wrapping of specially selected Fourier samples. The two implementations essentially dier by the choice of spatial grid

Emmanuel Cande?s; Laurent Demanet; David Donoho; Lexing Ying

2006-01-01

317

Martensitic transformation of Ca  

Microsoft Academic Search

At room temperature Ca undergoes a pressure-induced structural transformation at 20 GPa from the fcc structure into the more open packed bcc. We investigate a distortion model for this transformation that differs from the Bain mechanism usually invoked to describe this transformation and consists of a variant of the Burgers mechanism for the hcp-->bcc transformation. It is shown that the

Renata M. Wentzcovitch; Henry Krakauer

1990-01-01

318

Discrete Cosine Transform  

Microsoft Academic Search

A discrete cosine transform (DCT) is defined and an algorithm to compute it using the fast Fourier transform is developed. It is shown that the discrete cosine transform can be used in the area of digital processing for the purposes of pattern recognition and Wiener filtering. Its performance is compared with that of a class of orthogonal transforms and is

N. Ahmed; T. Natarajan; K. R. Rao

1974-01-01

319

Evaluate and characterize mechanisms controlling transport, fate and effects of Army smokes in the aerosol wind tunnel: Transport, transformations, fate, and terrestrial ecological effects of red phosphorus-butyl rubber and white phosphorus obscurant smokes: Final report  

SciTech Connect

An evaluation of the terrestrial transport, transformations and ecological effects of phosphorus (red phosphorus-butyl rubber (RP/BR)) smoke obscurant was performed at Pacific Northwest Laboratory. A similar evaluation using white phosphorus (WP) smoke/obscurant is currently proceeding. The objective is to characterize the effects of smokes and obscurants on: (1) natural vegetation characteristic of US Army training sites in the United States; (2) physical and chemical properties of representative of soils of those sites; and (3) soil microbiological communities. The influence and interactions of smoke/obscurant concentration, relative humidity (25%, 60%, 90% and simulated rain) and wind speed of 0.22 to 4.45 m/s by smoke is assessed. Five plant species and four soils were exposed to both single and repeated doses of RP/BR smokes in the Pacific Northwest Laboratory ''P-3'' rated recirculating environmental wind tunnel. Detailed results for RP/BR and limited results for WP are presented. Toxicity symptoms for plants exposed for 2, 4, 6, and 8 hours to concentrations of RP/BR ranging from 200 mg/m/sup 3/ included leaf tip burn, leaf curl, leaf abscission and drop, floral abortion, chlorosis, neucrotic spotting, wilting, desiccation and dieback. Grass and bushbean were the most sensitive. The intensity and duration of these effects varied. Soils effects data suggest that there is an increase in the mobility of selected trace elements after exposure; however, this effect appears to be ameliorated with time. Soil microbial community effects show a reduction in the production of nitrate after soil is exposed to RP/BR smoke. Most of the plant, soil and soil microbial effects are transient in nature and are somewhat less intense resulting from repeated exposures; however, there is evidence that some of these environmental impacts may be persistent. 43 refs., 44 figs., 67 tabs.

Van Voris, P.; Ligotke, M.W.; McFadden, K.M.; Li, S.M.W.; Thomas, B.L.; Cataldo, D.A.; Garland, T.R.; Fredrickson, J.K.; Bean, R.M.; Carlile, D.W.

1987-10-01

320

Arsenic(V) reduction in relation to Iron(III) transformation and molecular characterization of the structural and functional microbial community in sediments of a basin-fill aquifer in Northern Utah.  

PubMed

Basin-fill aquifers of the Southwestern United States are associated with elevated concentrations of arsenic (As) in groundwater. Many private domestic wells in the Cache Valley Basin, UT, have As concentrations in excess of the U.S. EPA drinking water limit. Thirteen sediment cores were collected from the center of the valley at the depth of the shallow groundwater and were sectioned into layers based on redoxmorphic features. Three of the layers, two from redox transition zones and one from a depletion zone, were used to establish microcosms. Microcosms were treated with groundwater (GW) or groundwater plus glucose (GW+G) to investigate the extent of As reduction in relation to iron (Fe) transformation and characterize the microbial community structure and function by sequencing 16S rRNA and arsenate dissimilatory reductase (arrA) genes. Under the carbon-limited conditions of the GW treatment, As reduction was independent of Fe reduction, despite the abundance of sequences related to Geobacter and Shewanella, genera that include a variety of dissimilatory iron-reducing bacteria. The addition of glucose, an electron donor and carbon source, caused substantial shifts toward domination of the bacterial community by Clostridium-related organisms, and As reduction was correlated with Fe reduction for the sediments from the redox transition zone. The arrA gene sequencing from microcosms at day 54 of incubation showed the presence of 14 unique phylotypes, none of which were related to any previously described arrA gene sequence, suggesting a unique community of dissimilatory arsenate-respiring bacteria in the Cache Valley Basin. PMID:24632255

Mirza, Babur S; Muruganandam, Subathra; Meng, Xianyu; Sorensen, Darwin L; Dupont, R Ryan; McLean, Joan E

2014-05-01

321

Arsenic(V) Reduction in Relation to Iron(III) Transformation and Molecular Characterization of the Structural and Functional Microbial Community in Sediments of a Basin-Fill Aquifer in Northern Utah  

PubMed Central

Basin-fill aquifers of the Southwestern United States are associated with elevated concentrations of arsenic (As) in groundwater. Many private domestic wells in the Cache Valley Basin, UT, have As concentrations in excess of the U.S. EPA drinking water limit. Thirteen sediment cores were collected from the center of the valley at the depth of the shallow groundwater and were sectioned into layers based on redoxmorphic features. Three of the layers, two from redox transition zones and one from a depletion zone, were used to establish microcosms. Microcosms were treated with groundwater (GW) or groundwater plus glucose (GW+G) to investigate the extent of As reduction in relation to iron (Fe) transformation and characterize the microbial community structure and function by sequencing 16S rRNA and arsenate dissimilatory reductase (arrA) genes. Under the carbon-limited conditions of the GW treatment, As reduction was independent of Fe reduction, despite the abundance of sequences related to Geobacter and Shewanella, genera that include a variety of dissimilatory iron-reducing bacteria. The addition of glucose, an electron donor and carbon source, caused substantial shifts toward domination of the bacterial community by Clostridium-related organisms, and As reduction was correlated with Fe reduction for the sediments from the redox transition zone. The arrA gene sequencing from microcosms at day 54 of incubation showed the presence of 14 unique phylotypes, none of which were related to any previously described arrA gene sequence, suggesting a unique community of dissimilatory arsenate-respiring bacteria in the Cache Valley Basin. PMID:24632255

Mirza, Babur S.; Muruganandam, Subathra; Meng, Xianyu; Sorensen, Darwin L.; Dupont, R. Ryan

2014-01-01

322

Revised transmission line model for electromagnetic characterization of metasurfaces  

NASA Astrophysics Data System (ADS)

We have revised the transmission line model with the purpose of simplifying the electromagnetic characterization of metasurfaces with both electric and magnetic responses. The revised model is an efficient tool for the case when a metasurface is located on top of a finite-thickness substrate or inside a finite-thickness slab. We have derived analytical expressions for the grid series impedance and shunt admittance of a substrated metasurface. The presented theory is illustrated by a numerical example of an array consisting of Mie-resonant silicon nanospheres. We have retrieved individual polarizabilities of a single sphere in a uniform host medium and compared them with the predictions of classical Mie theory. Further, we have studied a more practical case when the array of Si spheres is located on top of a finite-thickness glass substrate.

Albooyeh, M.; Ra'di, Y.; Adil, M. Q.; Simovski, C. R.

2013-08-01

323

Perfect NOT transformation and conjugate transformation  

E-print Network

The perfect NOT transformation, probabilistic perfect NOT transformation and conjugate transformation are studied. Perfect NOT transformation criteria on a quantum state set $S$ of a qubit are obtained. Two necessary and sufficient conditions for realizing a perfect NOT transformation on $S$ are derived. When these conditions are not satisfied we discuss a probabilistic perfect NOT transformation (gate). We construct a probabilistic perfect NOT machine (gate) by a general unitary-reduction operation. With a postselection of the measurement outcomes, the probabilistic NOT gate yields perfectly complements of the input states. We prove that one can realize probabilistically the NOT gate of the input states secretly chosen from a certain set $S=\\{|\\Psi_1>, |\\Psi_2>,..., |\\Psi_n>\\}$ if and only if $|\\Psi_1>, |\\Psi_2>,...,$ and $|\\Psi_n>$ are linearly independent. We also generalize the probabilistic NOT transformation to the conjugate transformation in the multi-level quantum system. The lower bound of the best possible efficiencies attained by a probabilistic perfect conjugate transformation are obtained.

Fengli Yan; Ting Gao; Zhichao Yan

2012-03-15

324

Performance Measures for Transform Data Coding  

Microsoft Academic Search

This paper develops performance criteria for evaluating transform data coding schemes under computational constraints. Computational constraints that conform with the proposed basis-restricted model give rise to suboptimal coding efficiency characterized by a rate-distortion relationR(D)similar in form to the theoretical rate-distortion function. Numerical examples of this performance measure are presented for Fourier, Walsh, Haar, and Karhunen-Loève transforms.

J. Pearl; H. Andrews; W. Pratt

1972-01-01

325

Nonlocalization Properties of Time Operators Transformations  

NASA Astrophysics Data System (ADS)

It is presented a general approach to the problem of extension of time operators and the associated Lambda transformations on singular measures. It is also shown that Lambda transformations defined on function spaces having the Urysohn property are non localized. Particular attention has been devoted to time and Lambda operators associated with the Walsh-Paley system and to a characterization of their domain and non locality.

Sorger, U.; Suchanecki, Z.

2015-03-01

326

Transformations of $W$-Type Entangled States  

E-print Network

The transformations of $W$-type entangled states by using local operations assisted with classical communication are investigated. For this purpose, a parametrization of the $W$-type states which remains invariant under local unitary transformations is proposed and a complete characterization of the local operations carried out by a single party is given. These are used for deriving the necessary and sufficient conditions for deterministic transformations. A convenient upper bound for the maximum probability of distillation of arbitrary target states is also found.

S. K?nta?; S. Turgut

2010-03-10

327

Determining the effect of thermal loading on the remaining useful life of a power transformer from its impedance versus frequency characteristic  

SciTech Connect

It is well known that cellulose materials used to insulate transformer windings gradually degrade during service due to a combination of thermal, mechanical, and electrical stresses. As a result the mechanical characteristics of the paper change during use and may affect the useful life of the transformer. It has generally been assumed that the electrical characteristics remain relatively constant throughout the aging process. If, however, thermal aging changes the electrical characteristics, it may be possible to gauge the thermal age of a transformer by externally monitoring these electrical characteristics over time. In this work, samples of oil impregnated thermally upgraded Kraft insulating paper are subjected to accelerated thermal aging. The relative dielectric constant and loss tangent are investigated by monitoring changes in capacitance and conductance as a function of frequency and thermal aging. This paper presents data showing that the thermal aging process produces changes in the electrical characteristics of the insulating system paper. An example is presented comparing the admittance versus frequency for a model of a 765 kV 500 MVA auto transformer. This demonstrates that the effect of aging can theoretically be observed from the terminals of the transformer.

Batruni, R.; Degeneff, R.C. [Rensselaer Polytechnic Inst., Troy, NY (United States). Electric Power Engineering Dept.] [Rensselaer Polytechnic Inst., Troy, NY (United States). Electric Power Engineering Dept.; Lebow, M.A. [Consolidated Edison Co., New York, NY (United States)] [Consolidated Edison Co., New York, NY (United States)

1996-07-01

328

Influence of composition of the near-surface graded-gap layer on the admittance of metal-insulator-semiconductor structures based on graded-gap MBE n-Hg1-xCdxTe in wide temperature range  

NASA Astrophysics Data System (ADS)

Influence of the CdTe content in a near-surface graded-gap layer on the admittance of MIS-structures fabricated on the basis of heteroepitaxial Hg1-xCdxTe (x = 0.22-0.23 and 0.31-0.32) films grown by molecular beam epitaxy was investigated in a wide temperature range. It is shown that a temperature drop from 77 K to 8 K results in a decrease of hysteresis of the capacitance-voltage (C-V) characteristics and a decrease of frequencies which corresponds to a high-frequency behaviour of C-V characteristics of MIS-structures based on n-HgCdTe (x = 0.22-0.23) with and without graded-gap layersand also for MIS-structures based on n-HgCdTe (x = 0.31-0.32). Temperature dependences of the resistance of the epitaxial film bulk and differential resistance of the space-charge region (SCR) in strong inversion mode were studied. The experimental results can be explained by the fact that for MIS-structures based on n-HgCdTe (x = 0.22-0.23) with the graded-gap layers and for MIS-structures based on n-HgCdTe (x = 0.31-0.32), the differential resistance of SCR is limited by Shockley-Read generation at 25-77 K. Differential resistance of SCR for MIS-structures based on n-HgCdTe (x = 0.22-0.23) without the graded-gap layers is limited by tunnelling through deep levels at 8-77 K.

Voitsekhovskii, A. V.; Nesmelov, S. N.; Dzyadukh, S. M.

2014-12-01

329

Influence of composition of the near-surface graded-gap layer on the admittance of metal-insulator-semiconductor structures based on graded-gap MBE n-Hg1-xCdxTe in wide temperature range  

NASA Astrophysics Data System (ADS)

Influence of the CdTe content in a near-surface graded-gap layer on the admittance of MIS-structures fabricated on the basis of heteroepitaxial Hg1-xCdxTe (x = 0.22-0.23 and 0.31-0.32) films grown by molecular beam epitaxy was investigated in a wide temperature range. It is shown that a temperature drop from 77 K to 8 K results in a decrease of hysteresis of the capacitance-voltage (C-V) characteristics and a decrease of frequencies which corresponds to a high-frequency behaviour of C-V characteristics of MIS-structures based on n-HgCdTe (x = 0.22-0.23) with and without graded-gap layersand also for MIS-structures based on n-HgCdTe (x = 0.31-0.32). Temperature dependences of the resistance of the epitaxial film bulk and differential resistance of the space-charge region (SCR) in strong inversion mode were studied. The experimental results can be explained by the fact that for MIS-structures based on n-HgCdTe (x = 0.22-0.23) with the graded-gap layers and for MIS-structures based on n-HgCdTe (x = 0.31-0.32), the differential resistance of SCR is limited by Shockley-Read generation at 25-77 K. Differential resistance of SCR for MIS-structures based on n-HgCdTe (x = 0.22-0.23) without the graded-gap layers is limited by tunnelling through deep levels at 8-77 K.

Voitsekhovskii, A. V.; Nesmelov, S. N.; Dzyadukh, S. M.

2014-09-01

330

Landscapes of transformation  

E-print Network

This thesis aims to examine the cultural effect of transformation through the lens of procedural techniques applied to the human body and architecture. The body and architecture both operate as landscapes of transformation. ...

Ambs, Emily (Emily Kiersten)

2007-01-01

331

Metrics for enterprise transformation  

E-print Network

The objective of this thesis is to depict the role of metrics in the evolving journey of enterprise transformation. To this end, three propositions are explored: (i) metrics and measurement systems drive transformation, ...

Blackburn, Craig D. (Craig David), S. M. Massachusetts Institute of Technology

2009-01-01

332

Equations For Rotary Transformers  

NASA Technical Reports Server (NTRS)

Equations derived for input impedance, input power, and ratio of secondary current to primary current of rotary transformer. Used for quick analysis of transformer designs. Circuit model commonly used in textbooks on theory of ac circuits.

Salomon, Phil M.; Wiktor, Peter J.; Marchetto, Carl A.

1988-01-01

333

28-Channel rotary transformer  

NASA Technical Reports Server (NTRS)

Transformer transmits power and digital data across rotating interface. Array has many parallel data channels, each with potential l megabaud data rate. Ferrite-cored transformers are spaced along rotor; airgap between them reduces crosstalk.

Mclyman, W. T.

1981-01-01

334

Probabilistically Accurate Program Transformations  

E-print Network

The standard approach to program transformation involves the use of discrete logical reasoning to prove that the transformation does not change the observable semantics of the program. We propose a new approach that, in ...

Misailovic, Sasa

335

DNA Transformation, Continued  

NSDL National Science Digital Library

DNA transformation is a naturally occurring but rare event in which DNA can be transferred into bacteria. In 1970, Morton Mandel and Akiko Higa discovered a way to make E. coli more 'competent' for transforming foreign DNA. Their calcium chloride method is widely used today to obtain high-efficiency transforming cells. This animation from Cold Spring Harbor Laboratory's Dolan DNA Learning Center presents the second part of explaining DNA transformation through a series of illustrations of the processes involved.

336

Face Recognition using Curvelet Transform  

E-print Network

Face recognition has been studied extensively for more than 20 years now. Since the beginning of 90s the subject has became a major issue. This technology is used in many important real-world applications, such as video surveillance, smart cards, database security, internet and intranet access. This report reviews recent two algorithms for face recognition which take advantage of a relatively new multiscale geometric analysis tool - Curvelet transform, for facial processing and feature extraction. This transform proves to be efficient especially due to its good ability to detect curves and lines, which characterize the human's face. An algorithm which is based on the two algorithms mentioned above is proposed, and its performance is evaluated on three data bases of faces: AT&T (ORL), Essex Grimace and Georgia-Tech. k-nearest neighbour (k-NN) and Support vector machine (SVM) classifiers are used, along with Principal Component Analysis (PCA) for dimensionality reduction. This algorithm shows good results, ...

Cohen, Rami

2011-01-01

337

Transforming Anxiety into ENERGYTM  

E-print Network

Transforming Anxiety into ENERGYTM How to Prevent Panic and Promote Productivity in Turbulent Times By Wendy Mack with contributions from Meredith Kimbell and Myron Radio #12;Transforming Anxiety into Energy, consultants, and researchers who shared their stories and expertise. 1 #12;Transforming Anxiety into Energy

Maryland, Baltimore County, University of

338

Transformations - Composition (NLVM)  

NSDL National Science Digital Library

This Java applet enables learners to explore compositions of two transformations (among sliding, flipping and turning) both informally and within a coordinate system. Students select and compose shapes and manipulate the transformations to see the effect on a transformed image. Links to instructions, activities and teacher/parent information are included.

2011-01-01

339

Robust Singular Spectrum Transform  

Microsoft Academic Search

Change Point Discovery is a basic algorithm needed in many time series mining applications including rule discovery, motif discovery, casual analysis, etc. Several techniques for change point discovery have been suggested including wavelet analysis, cosine transforms, CUMSUM, and Singular Spectrum Transform. Of these methods Singular Spectrum Transform (SST) have received much attention because of its generality and because it does

Yasser F. O. Mohammad; Toyoaki Nishida

2009-01-01

340

Spacetime transformation acoustics  

E-print Network

A recently proposed analogue transformation method has allowed the extension of transformation acoustics to general spacetime transformations. We analyze here in detail the differences between this new analogue transformation acoustics (ATA) method and the standard one (STA). We show explicitly that STA is not suitable for transformations that mix space and time. ATA takes as starting point the acoustic equation for the velocity potential, instead of that for the pressure as in STA. This velocity-potential equation by itself already allows for some transformations mixing space and time, but not all of them. We explicitly obtain the entire set of transformations that do not leave its form invariant. It is in these cases that ATA shows its true potential, allowing for building a transformation acoustics method that enables the full range of spacetime transformations. We provide an example of an important transformation which cannot be achieved with STA. Using this transformation, we design and simulate an acoustic frequency converter via the ATA approach. Furthermore, in those cases in which one can apply both the STA and ATA approaches, we study the different transformational properties of the corresponding physical quantities.

C. García-Meca; S. Carloni; C. Barceló; G. Jannes; J. Sánchez-Dehesa; A. Martínez

2014-07-08

341

Uniform discrete curvelet transform  

Microsoft Academic Search

An implementation of the discrete curvelet transform is proposed in this work. The transform is based on and has the same order of complexity as the Fast Fourier Transform (FFT). The discrete curvelet functions are defined by a parameterized family of smooth windowed functions that satisfies two conditions: i) 2? periodic; ii) their squares form a partition of unity. The

Truong T. Nguyen; Hervé Chauris

2010-01-01

342

Resonance transformer power conditioners  

Microsoft Academic Search

Designs for power conditioning systems based on the resonance transformer have been developed for applications requiring compact, lightweight power supplies ranging from average power levels of 10 kW to over 1 MW. The resonance transformer is a patented concept which depends on a set of resonant LC circuits to produce transformer-like voltage or current gain. Because this approach does not

R. M. Ness; S. G. E. Pronko; J. R. Cooper; E. Y. Chu

1990-01-01

343

Enabling transformation with TSAT  

Microsoft Academic Search

The transformational satellite communications system (TSAT) is one component of the global information grid (GIG) that will enable transformation to support the warfighting efforts for the United States of America and its allies. To support transformation, TSAT will be fully integrated with the standards developed for the GIG. This paper provides an overview of the challenges and approaches into this

D. M. Stround; Phong Pham Tran

2005-01-01

344

Alcohol and European transformation.  

PubMed

Against the background of papers and discussions from the East-West seminar at the European Conference on Health, Society and Alcohol, the differences and similarities in eastern and western European transformation processes are discussed. After some remarks on the general nature of eastern transition and western integration, the two sides of Europe are compared with respect to various alcohol-specific issues. It will be shown that the ongoing transition touches alcohol-related phenomena on a broad spectrum, and no single characterization (e.g. commercialization and the rise of market interests) is sufficient alone. The changing balance between state, markets and civil society provides, however, an interesting perspective for comparing alcohol-related changes in various European societies. Finally, the prospects for a common European alcohol agenda are discussed briefly from the point of view of international mobilization on the dimensions of state, markets and civil society. There are signs of increased cooperation along all dimensions, but an all-European alcohol agenda seems unlikely. PMID:9167285

Simpura, J

1997-03-01

345

G-Reflectors: Analogues of Householder Transformations in Scalar Product Spaces  

E-print Network

G-Reflectors: Analogues of Householder Transformations in Scalar Product Spaces D. Steven Mackey. Key words. scalar product, bilinear, sesquilinear, orthosymmetric, isotropic, Householder Niloufer Mackey Fran¸coise Tisseur Abstract We characterize the analogues of Householder transformations

Tisseur, Francoise

346

An experimental study and modeling of Transformer-Coupled Toroidal Plasma processing of materials  

E-print Network

The Transformer Coupled Toroidal Plasma (TCTP) source uses a high power density plasma formed in a toroidal-shaped chamber by transformer coupling using a magnetic core. The objectives of the thesis are (1) to characterize ...

Bai, Bo, Ph. D. Massachusetts Institute of Technology

2006-01-01

347

The conformational modification of serpins transforms Leukocyte Elastase Inhibitor into an endonuclease involved in apoptosis.  

E-print Network

The conformational modification of serpins transforms Leukocyte Elastase Inhibitor. Paris, F-75006, France. Running Title: A conformational modification transforms LEI into L-DNaseII Word characterized biochemical feature of apoptosis is degradation of genomic DNA into oligonucleosomes

348

Efficient Quantum Transforms  

E-print Network

Quantum mechanics requires the operation of quantum computers to be unitary, and thus makes it important to have general techniques for developing fast quantum algorithms for computing unitary transforms. A quantum routine for computing a generalized Kronecker product is given. Applications include re-development of the networks for computing the Walsh-Hadamard and the quantum Fourier transform. New networks for two wavelet transforms are given. Quantum computation of Fourier transforms for non-Abelian groups is defined. A slightly relaxed definition is shown to simplify the analysis and the networks that computes the transforms. Efficient networks for computing such transforms for a class of metacyclic groups are introduced. A novel network for computing a Fourier transform for a group used in quantum error-correction is also given.

Peter Hoyer

1997-02-12

349

Phase Transformation in Cast Superaustenitic Stainless Steels  

SciTech Connect

Superaustenitic stainless steels constitute a group of Fe-based alloys that are compositionally balanced to have a purely austenitic matrix and exhibit favorable pitting and crevice corrosion resistant properties and mechanical strength. However, intermetallic precipitates such as sigma and Laves can form during casting or exposure to high-temperature processing, which degrade the corrosion and mechanical properties of the material. The goal of this study was to accurately characterize the solid-solid phase transformations seen in cast superaustenitic stainless steels. Heat treatments were performed to understand the time and temperature ranges for intermetallic phase formations in alloys CN3MN and CK3MCuN. Microstructures were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy and wavelength dispersive spectroscopy (EDS, WDS). The equilibrium microstructures, composed primarily of sigma and Laves within purely austenitic matrices, showed slow transformation kinetics. Factors that determine the extent of transformation, including diffusion, nucleation, and growth, are discussed.

Nathaniel Steven Lee Phillips

2006-12-12

350

A new characteristic of Mobius transformations in hyperbolic geometry  

NASA Astrophysics Data System (ADS)

We present a new characterization of Mobius transformations by using two classes of hyperbolic geometric objects: Lambert quadrilaterals and Saccheri quadrilaterals. The proof is based on a geometric approach.

Yang, Shihai; Fang, Ainong

2006-07-01

351

A sesquiterpene coumarin ether from transformed roots of Tanacetum parthenium  

Microsoft Academic Search

The roots of Tanacetum parthenium transformed with Agrobacterium rhizogenes afforded, in addition to the known coumarin isofraxidin, a new isofraxidin drimenyl ether which was characterized as 9-epipectachol B by spectral methods.

Wanda Kisiel; Anna Stojakowska

1997-01-01

352

Transformations between symmetric sets of quantum states  

E-print Network

We investigate probabilistic transformations of quantum states from a `source' set to a `target' set of states. Such transforms have many applications. They can be used for tasks which include state-dependent cloning or quantum state discrimination, and as interfaces between systems whose information encodings are not related by a unitary transform, such as continuous-variable systems and finite-dimensional systems. In a probabilistic transform, information may be lost or leaked, and we explain the concepts of leak and redundancy. Following this, we show how the analysis of probabilistic transforms significantly simplifies for symmetric source and target sets of states. In particular, we give a simple linear program which solves the task of finding optimal transforms, and a method of characterizing the introduced leak and redundancy in information-theoretic terms. Using the developed techniques, we analyse a class of transforms which convert coherent states with information encoded in their relative phase to symmetric qubit states. Each of these sets of states on their own appears in many well studied quantum information protocols. Finally, we suggest an asymptotic realization based on quantum scissors.

Vedran Dunjko; Erika Andersson

2012-06-22

353

Phase Transformation Kinetics: Advanced Modeling Strategies  

NASA Astrophysics Data System (ADS)

Phase transformations in the solid state are often heterogeneous and can be described by concurring modes of nucleation, growth, and impingement. The classical Johnson-Mehl-Avrami-Kolmogorov-(JMAK-) model, although offering an easy-to-use description of the transformation kinetics, is limited to very specific cases of the transformation modes. Instead, a generalized modular model of phase transformation kinetics can be proposed that provides a flexible formalism adaptable to various modes of nucleation, growth, and impingement. Due to its large versatility, the modular model approach can be easily applied for characterization of phase transformation kinetics beyond the scope of classical JMAK(-type) modeling. Three different strategies recently employed for such advanced modeling are presented: (I) deliberate variation of the nucleation mode upon crystallization of an Fe-Ni-B metallic glass in order to determine separate activation energies for nucleation and growth, (II) incorporation of specific, dedicated modes for nucleation and growth kinetics for the allotropic hcp-fcc transformation in cobalt introducing driving-force-dependent rates of transformation, and (III) implementation of quantitative microstructural data for the description of the precipitation kinetics in a supersaturated CuCo alloy.

Rheingans, B.; Mittemeijer, E. J.

2013-09-01

354

ON GIRSANOV AND GENERALIZED FEYNMAN–KAC TRANSFORMATIONS FOR SYMMETRIC MARKOV PROCESSES  

Microsoft Academic Search

per, we investigate two important transformations for X, the Girsanov transform induced by M,t and the generalized Feynman-Kac transform induced by N,t. For the Girsanov transform, we present necessary and su cient conditions for which to induce a positive supermartingale and hence to determine another Markov process, X. Moreover, we charac-terize the symmetric Dirichlet form associated with the Girsanov trans-formed

CHUAN-ZHONG CHEN; ZHI-MING MA; WEI SUN; M. Röckner

2007-01-01

355

Atom-to-ion transformation time in singly charged ECRISs  

Microsoft Academic Search

We report a series of measurements performed to characterize the atom-to-ion transformation time in singly charged electron cyclotron resonance ion sources (ECRISs). Three ECRISs were used with He, Ne, Ar and Kr noble gases. The transformation time as a function of the support gas flow, the ionization efficiency, and source volume is presented and compared to a calculation made with

P. Jardin; W. Farabolini; G. Gaubert; J. Y. Pacquet; J. Cornell; F. Durantel; C. Huet-Equilbec; N. Lecesne; R. Leroy; M. G. Saint Laurent; C. Barué; C. Canet; M. Dubois; M. Dupuis; J.-L. Flambard; P. Lehérissier; F. Lemagnen; O. Tuske; A. C. C. Villari

2004-01-01

356

Quality factor concept in piezoceramic transformer performance description  

Microsoft Academic Search

A new general approach based on the quality factor concept to piezoceramic transformer (PT) performance description is proposed. The system's quality factor, material elastic anisotropy, and coupling factors of the input and output sections of an electrically excited and electrically loaded PT fully characterize its resonance and near-resonance behavior. The PT efficiency, transformation ratio, and input and output power were

Alex V. Mezheritsky

2006-01-01

357

Continuous curvelet transform  

Microsoft Academic Search

We discuss a Continuous Curvelet Transform (CCT), a transform f??f(a,b,?) of functions f(x1,x2) on R2 into a transform domain with continuous scale a>0, location b?R2, and orientation ??[0,2?). Here ?f(a,b,?)=?f,?ab?? projects f onto analyzing elements called curvelets?ab? which are smooth and of rapid decay away from an a by a rectangle with minor axis pointing in direction ?. We call

Emmanuel J. Candès; David L. Donoho

2005-01-01

358

Semantics of Database Transformations  

Microsoft Academic Search

. Database transformations arise in many different settings includingdatabase integration, evolution of database systems, and implementing user viewsand data-entry tools. This paper surveys approaches that have been taken to problemsin these settings, assesses their strengths and weaknesses, and develops requirementson a formal model for specifying and implementing database transformations.We also consider the problem of insuring the correctness of database transformations.In

Peter Buneman; Susan B. Davidson; Anthony Kosky

1995-01-01

359

Electrical characterization of a GaAs quantum well confined by GaAlAs layers or by two superlattices  

NASA Astrophysics Data System (ADS)

Capacitance-voltage, deep level transient spectroscopy (DLTS), and admittance spectroscopy measurements have been performed to characterize a GaAs quantum well confined either by Ga0.57Al0.43As layers or by two GaAs-Ga0.54Al0.46As superlattices. Due to a large capacitance decrease at low temperature, the well response cannot be obtained from DLTS measurements. This capacitance step is related to the thermionic emission from the well to the barrier regions. For the case of the enlarged well in the superlattice, the electron emission takes place towards the conduction miniband. In order to deduce the conduction-band discontinuity, admittance spectroscopy measurements have been applied. The bottom of the superlattice miniband is at 107±10 meV from the GaAs conduction-band minimum. The corresponding band offset deduced from a theoretical calculation is ?Ec=410±10 meV=(0.65±0.02) ?Eg. For the GaAs quantum well in GaAlAs, we measure a conduction-band discontinuity of 0.35 eV between GaAs and GaAlAs that has its minimum at the X point. At the ? point, the band offset ratio ?Ec/?Eg is once more confirmed.

Ababou, S.; Guillot, G.; Regreny, A.

1992-11-01

360

Magnetically Controlled Variable Transformer  

NASA Technical Reports Server (NTRS)

Improved variable-transformer circuit, output voltage and current of which controlled by use of relatively small current supplied at relatively low power to control windings on its magnetic cores. Transformer circuits of this type called "magnetic amplifiers" because ratio between controlled output power and power driving control current of such circuit large. This ratio - power gain - can be as large as 100 in present circuit. Variable-transformer circuit offers advantages of efficiency, safety, and controllability over some prior variable-transformer circuits.

Kleiner, Charles T.

1994-01-01

361

Amplified quantum transforms  

NASA Astrophysics Data System (ADS)

In this thesis we investigate two new Amplified Quantum Transforms. In particular we create and analyze the Amplified Quantum Fourier Transform (Amplified-QFT) and the Amplified-Haar Wavelet Transform. The Amplified-QFT algorithm is used to solve the Local Period Problem. We calculate the probabilities of success and compare this algorithm with the QFT and QHS algorithms. We also examine the Amplified-QFT algorithm for solving the Local Period Problem with Error Stream. We use the Amplified-Haar Wavelet Transform for solving the Local Constant or Balanced Signal Decision Problem which is a generalization of the Deutsch-Jozsa problem.

Cornwell, David J.

362

New geometrical approach for new Hough-like transforms  

NASA Astrophysics Data System (ADS)

Hough Transform, an important tool in image processing, does not use the analytical or geometrical properties of its basic objects, sine curves. Their replacement by other curves, namely circles, has led us to the discovery and the autonomous study of two families of transforms, named Circle and Envelope Transforms. These transforms, internal to the plane of study, are divided into three classes: parabolic, elliptic and hyperbolic, in connection with the Euclidean and the two non-Euclidean geometries. They are shown to be equivalent to Hough Transform. Three 'classical geometry' transforms interplay with envelope transforms: reciprocal polar transform, inversion transform and pedal transform. A unified view is brought by the introduction of the 'space of circles' equipped with a special quadratic form. This set of transforms can be applied successfully to conic curves in view of their characterization and detection. Almost every concept in this model is generalizable to 3D in a straightforward manner. Generalization is also promising for gray-level images in the direction of Radon Transform.

Becker, Jean-Marie

1998-10-01

363

Power transformer testing  

NASA Astrophysics Data System (ADS)

This paper presents the method of oil-filled transformer monitoring by means of a fiber optic sensor. Our method can be extremely useful in case of prevent overheating and the winding failure. A special semiconductor technology plays an important role in such measurement. The tests were carried out by means of the developed test stand imitating a real power transformer.

Zagrobelna, Magdalena; Wasilewski, Andrzej

2014-11-01

364

Facile transformation of Arabidopsis  

Microsoft Academic Search

A protocol is described for the simple, rapid and efficient production of transgenic Arabidopsis plants. The procedure was developed using growth regulator regimes that promote adventitious embryogenesis during or immediately following Agrobacterium mediated transformation. Both the RLD and Columbia genotypes of Arabidopsis were transformed using slightly different growth regulator regimes. For the Columbia genotype two modifications of the protocol were

László Márton; John Browse

1991-01-01

365

Direct current transformer  

NASA Technical Reports Server (NTRS)

A direct current transformer in which the primary consists of an elongated strip of superconductive material, across the ends of which is direct current potential is described. Parallel and closely spaced to the primary is positioned a transformer secondary consisting of a thin strip of magnetoresistive material.

Khanna, S. M.; Urban, E. W. (inventors)

1979-01-01

366

Transformer design tradeoffs  

NASA Technical Reports Server (NTRS)

Technical memorandum includes transformer area product numbers, which are used to summarize dimensional and electrical properties of C-cores, pot cores, lamination, powder cores, and tape-wound cores. To aid in core selection, comparison of five common core materials is presented to indicate their influence on overall transformer efficiency and weight.

Mclyman, W. T.

1977-01-01

367

Genetic Transformation of Bacteria.  

ERIC Educational Resources Information Center

An activity in which students transform an ampicillin-sensitive strain of E. coli with a plasmid containing a gene for ampicillin resistance is described. The procedure for the preparation of competent cells and the transformation of competent E. coli is provided. (KR)

Moss, Robert.

1991-01-01

368

Exploring Functional Mellin Transforms  

E-print Network

We define functional Mellin transforms within a scheme for functional integration proposed in [1]. Functional Mellin transforms can be used to define functional traces, logarithms, and determinants. The associated functional integrals are useful tools for probing function spaces in general and $C^\\ast$-algebras in particular. Several interesting aspects are explored.

J. LaChapelle

2015-01-08

369

Shiftable multiscale transforms  

Microsoft Academic Search

Orthogonal wavelet transforms have recently become a popular representation for multiscalesignal and image analysis. One of the major drawbacks of these representations istheir lack of translation invariance: the content of wavelet subbands is unstable under translationsof the input signal. Wavelet transforms are also unstable with respect to dilationsof the input signal, and in two dimensions, rotations of the input signal.

Eero P. Simoncelli; William T. Freeman; Edward H. Adelson; David J. Heeger

1992-01-01

370

Conformal transformation optics  

NASA Astrophysics Data System (ADS)

The field of transformation optics shows that media containing gradients in optical properties are equivalent to curved geometries of spacetime for the propagation of light. Conformal transformation optics -- a particular variant of this feature -- can be used to design devices with novel functionalities from inhomogeneous, isotropic dielectric media.

Xu, Lin; Chen, Huanyang

2015-01-01

371

Complex rectangular transforms  

Microsoft Academic Search

While deriving rectangular transforms Agarwal and cooley have used polynomial factors with real integer coefficients which resulted in real convolution matrices. In this paper, it is shown that the use of polynomial factors with complex integer coefficients yields new algorithms with complex convolution matrices, which require less number of multiplications than rectangular transforms. The paper outlines the derivation of the

V. Reddy; N. Reddy

1979-01-01

372

Biochemical transformation of coals  

DOEpatents

A method of biochemically transforming macromolecular compounds found in solid carbonaceous materials, such as coal is provided. The preparation of new microorganisms, metabolically weaned through challenge growth processes to biochemically transform solid carbonaceous materials at extreme temperatures, pressures, pH, salt and toxic metal concentrations is also disclosed.

Lin, Mow S. (Rocky Point, NY); Premuzic, Eugene T. (East Moriches, NY)

1999-03-23

373

Transforming the supply chain  

Microsoft Academic Search

Purpose – Today's business environment emerges the need for organizations to continuously transform themselves, in order to maintain and reinforce their ability to compete successfully. The purpose of this paper is to present an analysis of the transformation process of supply chain in order to provide a modular structured management tool for planning, implementing and measure the effectiveness of supply

Evangelia D. Fassoula

2006-01-01

374

Biochemical transformation of coals  

DOEpatents

A method of biochemically transforming macromolecular compounds found in solid carbonaceous materials, such as coal is provided. The preparation of new microorganisms, metabolically weaned through challenge growth processes to biochemically transform solid carbonaceous materials at extreme temperatures, pressures, pH, salt and toxic metal concentrations is also disclosed. 7 figs.

Lin, M.S.; Premuzic, E.T.

1999-03-23

375

Deployment & Market Transformation (Brochure)  

SciTech Connect

NREL's deployment and market transformation (D and MT) activities encompass the laboratory's full range of technologies, which span the energy efficiency and renewable energy spectrum. NREL staff educates partners on how they can advance sustainable energy applications and also provides clients with best practices for reducing barriers to innovation and market transformation.

Not Available

2012-04-01

376

Support Principals, Transform Schools  

ERIC Educational Resources Information Center

The Transformational Coaching Team in Oakland Unified School District provides differentiated, sustained, job-embedded support to the district's school leaders. In this article, members of the team describe how they work with principals to transform the culture of schools. Student achievement data show above-average improvement in schools in which…

Aguilar, Elena; Goldwasser, Davina; Tank-Crestetto, Kristina

2011-01-01

377

Transforming Dentistry through Innovation  

E-print Network

7 Transforming Dentistry through Innovation and Imagination Research Matters Faculty Highlights's practitioners and researchers through... DentistryF A C U L T Y O F TRANSFORMING DENTISTRY THROUGH INNOVATION a short time ago, were not possible. Naturally, these changes are influencing the teaching of dentistry

Barthelat, Francois

378

The Curvelet Transform  

Microsoft Academic Search

Multiresolution methods are deeply related to image processing, biological and computer vision, and scientific computing. The curvelet transform is a multiscale directional transform that allows an almost optimal nonadaptive sparse representation of objects with edges. It has generated increasing interest in the community of applied mathematics and signal processing over the years. In this article, we present a review on

Jianwei Ma; Gerlind Plonka

2010-01-01

379

Transformations in Milton's "Comus"  

E-print Network

of interventi. on by a deity. Thus, in Rook VIII, Minerva transforms Icarus into a partridge; in Hook X, Venus changes Adonis into an anemone; i. n Rook XV, Diana changes Zgcria into a tree. However, transforms. tion may be within +he cl"aracter's own power...

Yu, Hung-Chih

1969-01-01

380

Martensitic transformation of Ca  

NASA Astrophysics Data System (ADS)

At room temperature Ca undergoes a pressure-induced structural transformation at 20 GPa from the fcc structure into the more open packed bcc. We investigate a distortion model for this transformation that differs from the Bain mechanism usually invoked to describe this transformation and consists of a variant of the Burgers mechanism for the hcp-->bcc transformation. It is shown that the Bain mechanism is a specific case of this more general triclinic distortion, and therefore that a path in this larger parameter space provides a different energy route when compared with that derived from the tetragonal Bain strain, which is lower in energy at some points. This finding is particularly relevant for future studies of temperature-induced fcc-->bcc transformations. Our first-principles total-energy local-density-approximation study is accomplished by using the full-potential linear-augmented-plane-wave method.

Wentzcovitch, Renata M.; Krakauer, Henry

1990-09-01

381

Logarithmic transformation of response Logarithmic transformation of response  

E-print Network

Logarithmic transformation of response Logarithmic transformation of response Often, support S of Y is S = (0, ). Logarithm is then one of transformations to consider when trying to obtain a correct (wrong. Model Building 1. Transformation of response #12;Logarithmic transformation of response When does

Komarek, Arnost

382

Program Transformation Mechanics A Classification of Mechanisms for Program Transformation  

E-print Network

Program Transformation Mechanics A Classification of Mechanisms for Program Transformation with a Survey of Existing Transformation Systems Jonne van Wijngaarden Eelco Visser UU-CS-2003-048 Institute Transformation Mechanics A Classification of Mechanisms for Program Transformation with a Survey of Existing

Utrecht, Universiteit

383

Brain Shape Characterization from Deformation  

PubMed Central

The characterization of shape in the brain is of great importance for understanding differences in structure and the relationship to function. Structural differences have been associated with, for example, age, sex, handedness, cognitive abilities and many neurologic and psychiatric conditions. Nonrigid registration methods enable the characterization of shape differences between images based on the transformation that relates them. Unlike methods which characterize shape in terms of geometric features computed from individual structures, transformation-based deformation description characterizes the entire space and therefore may better reflect the interrelationships between structures, as well as changes within and near structure. The transformation, as characterized by the local Jacobian, can yield an expressive description of local shape differences. PMID:20216923

Staib, Lawrence H.; Jackowski, Marcel; Papademetris, Xenophon

2010-01-01

384

Vol. 171, No. 7 Transposon Mutagenesis, Characterization, and Cloning of  

E-print Network

individually for DNA uptake, transformation efficiency, UV sensitivity, and growth rate. The transformationVol. 171, No. 7 Transposon Mutagenesis, Characterization, and Cloning of Transformation Genes coli with mini-TnlOkan. The mutagenized PstI fragments were introduced by transformation into the H

Redfield, Rosemary J. "Rosie"

385

Some Properties of Transforms in Cultural Theory  

NASA Astrophysics Data System (ADS)

It is shown that, in certain circumstances, systems of cultural rules may be represented by doubly stochastic matrices denoted ?, called “possibility transforms,” and by certain real valued “possibility densities” ?=( ? 1, ? 2,…, ? n ) with inner product characterize a certain problem of ethnographic or ethological description as a problem of prediction, in which observations are predicted by properties of fixed points of transforms of “pure systems”, or by properties of convex combinations of such “pure systems”. Other relationships to quantum methods are noted.

Ballonoff, Paul

2010-12-01

386

Characterization of a Transforming N-ras Gene in the Human Hepatoma Cell Line Hep G2: Additional Evidence for the Importance of c-myc and ras Cooperation in Hepatocarcinogenesis  

Microsoft Academic Search

The expression of the c-myc gene has previously been shown to be elevated and deregulated in the human hepatoma cell line Hep G2 (B. E. Huber and S. S. Thorgeirsson, Cancer Res., 47: 3414-3420, 1987). We now report that the Hep G2 N-ras gene is activated to a dominant- acting, transforming gene by a missense mutation in codon 61. Hep

Cynthia A. Richards; Steven A. Short; Snorri S. Thorgeirsson; Brian E. Huber

1990-01-01

387

Transformer Abdullah Al-Otaibi  

E-print Network

Transformer Abdullah Al-Otaibi ID#242374 Section#2 Abstract- this is a brief description for transformer and how it works. I. DEFINITION A transformer is a device that transfers electrical energy from of the transformer in 1831. The transformer is used by Faraday only to demonstrate the principle of electromagnetic

Masoudi, Husain M.

388

A discrete fractional random transform  

E-print Network

We propose a discrete fractional random transform based on a generalization of the discrete fractional Fourier transform with an intrinsic randomness. Such discrete fractional random transform inheres excellent mathematical properties of the fractional Fourier transform along with some fantastic features of its own. As a primary application, the discrete fractional random transform has been used for image encryption and decryption.

Zhengjun Liu; Haifa Zhao; Shutian Liu

2006-05-20

389

The Practice of Transformative Pedagogy  

ERIC Educational Resources Information Center

The author examined the practice of transformative pedagogy in an undergraduate teacher education program. The research was guided by two questions: What is the impact of transformative pedagogy on fostering preservice teachers' transformative learning? and What practices of transformative pedagogy impact student transformative learning?…

Ukpokodu, Omiunota

2009-01-01

390

Thermal evaporation and characterization of superstrate CdS/Sb2Se3 solar cells  

NASA Astrophysics Data System (ADS)

Sb2Se3 is a very promising absorber material for thin film photovoltaics because of its ideal band gap, strong optical absorption, and non-toxic and earth-abundant constituents. However, only until this year Sb2Se3 solar cell was reported. Here, we present the fabrication and characterization of thermally evaporated superstrate CdS/Sb2Se3 solar cell. Our device achieved a power conversion efficiency of 1.9% (Voc = 300 mV, Jsc = 13.2 mA/cm2, and FF = 48%) and showed good stability. Moreover, using current-voltage measurement, admittance spectroscopy, capacitance-voltage profiling, and drive level capacitance profiling, device characteristics and performance limiting factors are revealed and discussed.

Luo, Miao; Leng, Meiying; Liu, Xinsheng; Chen, Jie; Chen, Chao; Qin, Sikai; Tang, Jiang

2014-04-01

391

Overview of transformer platform showing three original stepup transformer (center), ...  

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

Overview of transformer platform showing three original step-up transformer (center), steel switchback (right), and modern step-down transformer (foreground), view to northwest - Morony Hydroelectric Facility, Dam and Powerhouse, Morony Dam Road, Great Falls, Cascade County, MT

392

Lorentz transformation by mimicking the Lorentz transformation  

E-print Network

We show that starting with the fact that special relativity theory is concerned with a distortion of the observed length of a moving rod, without mentioning if it is a "contraction" or "dilation", we can derive the Lorentz transformations for the spacetime coordinates of the same event. This derivation is based on expressing the length of the moving rod as a sum of components with all the lengths involved in this summation being measured by the observers of the same inertial reference frame.

Bernhard Rothenstein; Stefan Popescu

2007-09-24

393

Lapped transforms for efficient transform\\/subband coding  

Microsoft Academic Search

Two lapped transforms for subband\\/transform coding of signals are introduced: a version of the lapped orthogonal transform (LOT), which can be efficiently computed for any transform length; and the modulated lapped transform (MLT), which is based on a modulated quadrature mirror (QMF) bank. The MLT can also be efficiently computed by means of a type-IV discrete sine transform (DST-IV). The

H. S. Malvar

1990-01-01

394

Transformer design tradeoffs  

NASA Technical Reports Server (NTRS)

Material was presented to assist transformer designers in the transition from long-used English units to the less familiar metric equivalents. A coordination between the area product numbers ap (product of window and core cross-section areas) and current density J was developed for a given regulation and temperature rise. Straight-line relationships for Ap and Volume, Ap and surface area At and, Ap and weight were developed. These relationships can now be used as new tools to simplify and standardize the process of transformer design. They also made it possible to design transformers of small bulk and volume or to optimize efficiency.

Mclyman, W. T.

1976-01-01

395

Biolistics Transformation of Wheat  

NASA Astrophysics Data System (ADS)

We present a complete, step-by-step guide to the production of transformed wheat plants using a particle bombardment device to deliver plasmid DNA into immature embryos and the regeneration of transgenic plants via somatic embryogenesis. Currently, this is the most commonly used method for transforming wheat and it offers some advantages. However, it will be interesting to see whether this position is challenged as facile methods are developed for delivering DNA by Agrobacterium tumefaciens or by the production of transformants via a germ-line process (see other chapters in this book).

Sparks, Caroline A.; Jones, Huw D.

396

25. VIEW, LOOKING SOUTHWEST INSIDE TRANSFORMER ROOM, SHOWING TRANSFORMERS AND ...  

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

25. VIEW, LOOKING SOUTHWEST INSIDE TRANSFORMER ROOM, SHOWING TRANSFORMERS AND KNIFE SWITCHES - Sacramento River Bridge, Spanning Sacramento River at California State Highway 275, Sacramento, Sacramento County, CA

397

Relativistic Transformation of Solid Angle.  

ERIC Educational Resources Information Center

Rederives the relativistic transformations of light intensity from compact sources (stars) to show where and how the transformation of a solid angle contributes. Discusses astrophysical and other applications of the transformations. (Author/CS)

McKinley, John M.

1980-01-01

398

Transforming California's Freight Transport System  

E-print Network

Transforming California's Freight Transport System Policy Forum on the Role of Freight Transport Standard #12;2050 Vision- Key Conceptual Outcomes Technology Transformation Early Action Cleaner Combustion Multiple Strategies Federal Action Efficiency Gains Energy Transformation 9 #12;Further reduce localized

California at Davis, University of

399

Fourier Transform Infrared (FTIR) Spectroscopy  

E-print Network

Fourier Transform Infrared (FTIR) Spectroscopy Klaus Gerwert, Lehrstuhl fu¨r Biophysik, Ruhr Transform IR by Johannes Orphal. Fourier transform infrared (FTIR) spectroscopy is an experimental technique information on molecular structure, chemical bondingandmolecularenvironment.Formanyyears,FTIR has been

Gerwert, Klaus

400

Plant improvement Investigations on transforming  

E-print Network

Plant improvement Investigations on transforming Triticum aestivum via the pollen tube pathway N the necessary conditions to transform wheat Triticum aestivum using the pollen tube pathway. Three methods. Triticum aestivum = wheat / transformation / pollen / nuclease Résumé — Recherches sur la

Paris-Sud XI, Université de

401

How Political Science Became Modern: Racial Thought and the Transformation of the Discipline, 1880-1930  

ERIC Educational Resources Information Center

This dissertation argues that changing ideas about race and engagement with race science were at the heart of a major transformation of political science in the 1920s, a transformation that I characterize as "becoming modern." This transformation was at once conceptual--visible in the basic categories and theoretical apparatus of the…

Blatt, Jessica

2009-01-01

402

Acceptance by Transformation Monoids (with an Application to Local Self Reductions)  

Microsoft Academic Search

We study the power of transformation monoids, which are used as an acceptance mechanism of nondeterministic polynomial time machines. Focussing our attention on four types of transformation monoids (including the monoids of all transformations on k elements) we obtain exact characterizations of all investigated polynomial time classes. We apply these results to the cases of locally self reducible sets and

Ulrich Hertrampf

1997-01-01

403

Fourier transform mass spectrometry.  

PubMed

This article provides an introduction to Fourier transform-based mass spectrometry. The key performance characteristics of Fourier transform-based mass spectrometry, mass accuracy and resolution, are presented in the view of how they impact the interpretation of measurements in proteomic applications. The theory and principles of operation of two types of mass analyzer, Fourier transform ion cyclotron resonance and Orbitrap, are described. Major benefits as well as limitations of Fourier transform-based mass spectrometry technology are discussed in the context of practical sample analysis, and illustrated with examples included as figures in this text and in the accompanying slide set. Comparisons highlighting the performance differences between the two mass analyzers are made where deemed useful in assisting the user with choosing the most appropriate technology for an application. Recent developments of these high-performing mass spectrometers are mentioned to provide a future outlook. PMID:21742802

Scigelova, Michaela; Hornshaw, Martin; Giannakopulos, Anastassios; Makarov, Alexander

2011-07-01

404

Fractals and Transformations.  

ERIC Educational Resources Information Center

Discussed are several different transformations based on the generation of fractals including self-similar designs, the chaos game, the koch curve, and the Sierpinski Triangle. Three computer programs which illustrate these concepts are provided. (CW)

Bannon, Thomas J.

1991-01-01

405

Transformer design tradeoffs  

NASA Technical Reports Server (NTRS)

In space, power system transformer components are frequently the heaviest and bulkiest items in the power conversion circuit. They also have a significant effect upon the overall performance and efficiency of the system. Accordingly, the design of such transformers has an important effect on overall system weight, power-inversion efficiency, and cost. Relationships were between the parameters used by transformer designers that can be used as new tools to standardize and simplify transformer design. They can be used to optimize the design either for small size and weight or efficiency. The metric system of units, rather than the familiar English units, is used; however, material is presented to assist the reader in the transition from one system to the other.

Mclyman, W. T.

1977-01-01

406

Applying Improved Efficiency Transformers  

E-print Network

Today's business and energy conscious environment affords both producers and consumers of electric energy an opportunity to reduce costs and conserve energy through the use of improved efficiency transformers. Various design techniques...

Haggerty, N. K.; Malone, T. P.

407

The Quantum Mellin transform  

E-print Network

We uncover a new type of unitary operation for quantum mechanics on the half-line which yields a transformation to ``Hyperbolic phase space''. We show that this new unitary change of basis from the position x on the half line to the Hyperbolic momentum $p_\\eta$, transforms the wavefunction via a Mellin transform on to the critial line $s=1/2-ip_\\eta$. We utilise this new transform to find quantum wavefunctions whose Hyperbolic momentum representation approximate a class of higher transcendental functions, and in particular, approximate the Riemann Zeta function. We finally give possible physical realisations to perform an indirect measurement of the Hyperbolic momentum of a quantum system on the half-line.

J. Twamley; G. J. Milburn

2007-02-12

408

Transformation inverse design  

E-print Network

We present a new technique for the design of transformation-optics devices based on large-scale optimization to achieve the optimal effective isotropic dielectric materials within prescribed index bounds, which is ...

Liu, David

409

Improved Transformation of Anthurium  

Technology Transfer Automated Retrieval System (TEKTRAN)

Methods to increase transformation efficiency and yields of transgenic Anthurium andraeanum Linden ex. André hybrids were sought while effecting gene transfer for resistance to the two most important pests, bacterial blight (Xanthomonas axonopodis pv. dieffenbachiae) and nematodes (Radopholus simili...

410

Series Transmission Line Transformer  

DOEpatents

A series transmission line transformer is set forth which includes two or more of impedance matched sets of at least two transmissions lines such as shielded cables, connected in parallel at one end ans series at the other in a cascading fashion. The cables are wound about a magnetic core. The series transmission line transformer (STLT) which can provide for higher impedance ratios and bandwidths, which is scalable, and which is of simpler design and construction.

Buckles, Robert A. (Livermore, CA); Booth, Rex (Livermore, CA); Yen, Boris T. (El Cerrito, CA)

2004-06-29

411

Functional Mellin Transforms  

E-print Network

Functional integrals are defined in terms of locally compact topological groups and their associated Banach-valued Haar integrals. This approach generalizes the functional integral scheme of Cartier and DeWitt-Morette. The definition allows a construction of functional Mellin transforms. In turn, the functional Mellin transforms can be used to define functional traces, logarithms, and determinants. The associated functional integrals are useful tools for probing function spaces in general and $C^\\ast$-algebras in particular. Several interesting aspects are explored.

J. LaChapelle

2015-01-07

412

Plant transformation technology  

Microsoft Academic Search

Plant transformation has its roots in the research on Agrobacterium that was being undertaken in the early 1980s. The last two decades have seen significant developments in plant transformation\\u000a technology, such that a large number of transgenic crop plants have now been released for commercial production. Advances\\u000a in the technology have been due to development of a range of Agrobacterium-mediated

Christine A. Newell

2000-01-01

413

Selection of Transformed Plants  

NASA Astrophysics Data System (ADS)

The low frequency and randomness of transgene integration into host cells, combined with the significant challenges of recovering whole plants from those rare events, makes the use of selectable marker genes routine in plant transformation experiments. For research applications that are unlikely to be grown in the field, strong herbicide- or antibiotic resistance is commonly used. Here we use genes conferring resistance to glufosinate herbicides as an example of a selectable marker in wheat transformation by either Agrobacterium or biolistics.

Jones, Huw D.; Sparks, Caroline A.

414

Transforming Undergraduate Science Education  

NASA Astrophysics Data System (ADS)

I'll describe: (1) how efforts to transform Astronomy 101 align with the goals the NRC Committee on Undergraduate Science Education, which I chair; (2) how information technology might be used to advance these goals; and (3) some experiences from our efforts to transform astronomy 101 at the University of Colorado. My work has been supported by grants from the NSF and the Pew Grant Program in Course Redesign.

McCray, R.

2001-12-01

415

Planar LTCC transformers for high voltage flyback converters.  

SciTech Connect

This paper discusses the design and use of low-temperature (850 C to 950 C) co-fired ceramic (LTCC) planar magnetic flyback transformers for applications that require conversion of a low voltage to high voltage (> 100V) with significant volumetric constraints. Measured performance and modeling results for multiple designs showed that the LTCC flyback transformer design and construction imposes serious limitations on the achievable coupling and significantly impacts the transformer performance and output voltage. This paper discusses the impact of various design factors that can provide improved performance by increasing transformer coupling and output voltage. The experiments performed on prototype units demonstrated LTCC transformer designs capable of greater than 2 kV output. Finally, the work investigated the effect of the LTCC microstructure on transformer insulation. Although this paper focuses on generating voltages in the kV range, the experimental characterization and discussion presented in this work applies to designs requiring lower voltage.

Schofield, Daryl (NASCENT Technology Inc. , Watertown, SD); Schare, Joshua M.; Glass, Sarah Jill; Roesler, Alexander William; Ewsuk, Kevin Gregory; Slama, George (NASCENT Technology Inc. , Watertown, SD); Abel, Dave (NASCENT Technology Inc. , Watertown, SD)

2007-06-01

416

Solid-state current transformer  

NASA Technical Reports Server (NTRS)

A signal transformation network which is uniquely characterized to exhibit a very low input impedance while maintaining a linear transfer characteristic when driven from a voltage source and when quiescently biased in the low microampere current range is described. In its simplest form, it consists of a tightly coupled two transistor network in which a common emitter input stage is interconnected directly with an emitter follower stage to provide virtually 100 percent negative feedback to the base input of the common emitter stage. Bias to the network is supplied via the common tie point of the common emitter stage collector terminal and the emitter follower base stage terminal by a regulated constant current source, and the output of the circuit is taken from the collector of the emitter follower stage.

Farnsworth, D. L. (inventor)

1976-01-01

417

Floral Transformation of Wheat  

NASA Astrophysics Data System (ADS)

A method is described for the floral transformation of wheat using a protocol similar to the floral dip of Arabidopsis. This method does not employ tissue culture of dissected embryos, but instead pre-anthesis spikes with clipped florets at the early, mid to late uninucleate microspore stage are dipped in Agrobacterium infiltration media harboring a vector carrying anthocyanin reporters and the NPTII selectable marker. T1 seeds are examined for color changes induced in the embryo by the anthocyanin reporters. Putatively transformed seeds are germinated and the seedlings are screened for the presence of the NPTII gene based on resistance to paromomycin spray and assayed with NPTII ELISAs. Genomic DNA of putative transformants is digested and analyzed on Southern blots for copy number to determine whether the T-DNA has integrated into the nucleus and to show the number of insertions. The non-optimized transformation efficiencies range from 0.3 to 0.6% (number of transformants/number of florets dipped) but the efficiencies are higher in terms of the number of transformants produced/number of seeds set ranging from 0.9 to 10%. Research is underway to maximize seed set and optimize the protocol by testing different Agrobacterium strains, visual reporters, vectors, and surfactants.

Agarwal, Sujata; Loar, Star; Steber, Camille; Zale, Janice

418

Facilities: NHMFL 9.4 Tesla Fourier Transform Ion Cyclotron Resonance Mass Spectrometer Citation: Characterization of Pine Pellet and Peanut Hull Pyrolysis of Bio-Oils by Negative-Ion Electrospray Ionization Fourier  

E-print Network

: Characterization of Pine Pellet and Peanut Hull Pyrolysis of Bio-Oils by Negative-Ion Electrospray Ionization pine pellets and peanut hulls, generates a hydrocarbon-rich liquid product (bio-oil) consisting of oily solubility. Peanut hull bio-oil is much more compositionally complex and contains more nitrogen

Weston, Ken

419

Transformation in fungi.  

PubMed Central

Transformation with exogenous deoxyribonucleic acid (DNA) now appears to be possible with all fungal species, or at least all that can be grown in culture. This field of research is at present dominated by Saccharomyces cerevisiae and two filamentous members of the class Ascomycetes, Aspergillus nidulans and Neurospora crassa, with substantial contributions also from fission yeast (Schizosaccharomyces pombe) and another filamentous member of the class Ascomycetes, Podospora anserina. However, transformation has been demonstrated, and will no doubt be extensively used, in representatives of most of the main fungal classes, including Phycomycetes, Basidiomycetes (the order Agaricales and Ustilago species), and a number of the Fungi Imperfecti. The list includes a number of plant pathogens, and transformation is likely to become important in the analysis of the molecular basis of pathogenicity. Transformation may be maintained either by using an autonomously replicating plasmid as a vehicle for the transforming DNA or through integration of the DNA into the chromosomes. In S. cerevisiae and other yeasts, a variety of autonomously replicating plasmids have been used successfully, some of them designed for use as shuttle vectors for Escherichia coli as well as for yeast transformation. Suitable plasmids are not yet available for use in filamentous fungi, in which stable transformation is dependent on chromosomal integration. In Saccharomyces cerevisiae, integration of transforming DNA is virtually always by homology; in filamentous fungi, in contrast, it occurs just as frequently at nonhomologous (ectopic) chromosomal sites. The main importance of transformation in fungi at present is in connection with gene cloning and the analysis of gene function. The most advanced work is being done with S. cerevisiae, in which the virtual restriction of stable DNA integration to homologous chromosome loci enables gene disruption and gene replacement to be carried out with greater precision and efficiency than is possible in other species that show a high proportion of DNA integration events at nonhomologous (ectopic) sites. With a little more trouble, however, the methodology pioneered for S. cerevisiae can be applied to other fungi too. Transformation of fungi with DNA constructs designed for high gene expression and efficient secretion of gene products appears to have great commercial potential. PMID:2651864

Fincham, J R

1989-01-01

420

Residential market transformation: National and regional indicators  

SciTech Connect

A variety of programs are underway to address market barriers to the adoption of energy-efficient residential technologies and practices. Most are administered by utilities, states, or regions that rely on the Energy Star as a consistent platform for program marketing and messaging. This paper reviews regional and national market transformation activities for three key residential end-uses -- air conditioning, clothes washing, and lighting -- characterizing current and ongoing programs; reporting on progress; identifying market indicators; and discussing implications.

Van Wie McGrory, Laura L.; McNamara, Maureen; Suozzo, Margaret

2000-06-01

421

Wavelets associated with Hankel transform and their Weyl transforms  

Microsoft Academic Search

The Hankel transform is an important transform. In this paper, we study the wavelets associated with the Hankel transform,\\u000a then define the Weyl transform of the wavelets. We give criteria of its boundedness and compactness on the L\\u000a p — spaces.

Lizhong Peng; Ruiqin Ma

2004-01-01

422

From transformation traces to transformation rules: Assisting Model Driven Engineering  

E-print Network

From transformation traces to transformation rules: Assisting Model Driven Engineering approach. In this paper we are interested in semi-automatically gen- erating labelled graph (model) transformations conform to a particu- lar syntax (meta-model). Those transformations are basic operations in model driven

Paris-Sud XI, Université de

423

Laplace Transforms An integral transform is an operator  

E-print Network

9­28­1998 Laplace Transforms An integral transform is an operator F (s) = Z b a K(s; t)f(t) dt: The input to the transform is the function f(t); the output is the function F (s). (By convention, small letters denote the inputs to a transform, and the corresponding capital letters denote the corresponding

Ikenaga, Bruce

424

Optical transformation from chirplet to fractional Fourier transformation kernel  

E-print Network

We find a new integration transformation which can convert a chirplet function to fractional Fourier transformation kernel, this new transformation is invertible and obeys Parseval theorem. Under this transformation a new relationship between a phase space function and its Weyl-Wigner quantum correspondence operator is revealed.

Hong-yi Fan; Li-yun Hu

2009-02-11

425

Verification of ATL Transformations Using Transformation Models and Model Finders  

E-print Network

Verification of ATL Transformations Using Transformation Models and Model Finders Fabian Büttner1 elements of the software to be built. If models are specified well, transformations can be em- ployed by a transformation from valid input models are valid, too, where validity refers to the metamodel constraints, often

Gogolla, Martin - Fachbereich 3

426

Verification of ATL Transformations Using Transformation Models and Model Finders  

E-print Network

Verification of ATL Transformations Using Transformation Models and Model Finders Fabian Büttner1, transformations can be em- ployed for different purposes, e.g., to produce final code. However, it is impor- tant that models produced by a transformation from valid input models are valid, too, where validity refers

Paris-Sud XI, Université de

427

Phase Transformations in Binary Colloidal Monolayers  

E-print Network

Phase transformations can be difficult to characterize at the microscopic level due to the inability to directly observe individual atomic motions. Model colloidal systems, by contrast, permit the direct observation of individual particle dynamics and of collective rearrangements, which allows for real-space characterization of phase transitions. Here, we study a quasi-two-dimensional, binary colloidal alloy that exhibits liquid-solid and solid-solid phase transitions, focusing on the kinetics of a diffusionless transformation between two crystal phases. Experiments are conducted on a monolayer of magnetic and nonmagnetic spheres suspended in a thin layer of ferrofluid and exposed to a tunable magnetic field. A theoretical model of hard spheres with point dipoles at their centers is used to guide the choice of experimental parameters and characterize the underlying materials physics. When the applied field is normal to the fluid layer, a checkerboard crystal forms; when the angle between the field and the normal is sufficiently large, a striped crystal assembles. As the field is slowly tilted away from the normal, we find that the transformation pathway between the two phases depends strongly on crystal orientation, field strength, and degree of confinement of the monolayer. In some cases, the pathway occurs by smooth magnetostrictive shear, while in others it involves the sudden formation of martensitic plates.

Ye Yang; Lin Fu; Catherine Marcoux; Joshua E. S. Socolar; Patrick Charbonneau; Benjamin B. Yellen

2015-02-10

428

Phase transformations in binary colloidal monolayers.  

PubMed

Phase transformations can be difficult to characterize at the microscopic level due to the inability to directly observe individual atomic motions. Model colloidal systems, by contrast, permit the direct observation of individual particle dynamics and of collective rearrangements, which allows for real-space characterization of phase transitions. Here, we study a quasi-two-dimensional, binary colloidal alloy that exhibits liquid-solid and solid-solid phase transitions, focusing on the kinetics of a diffusionless transformation between two crystal phases. Experiments are conducted on a monolayer of magnetic and nonmagnetic spheres suspended in a thin layer of ferrofluid and exposed to a tunable magnetic field. A theoretical model of hard spheres with point dipoles at their centers is used to guide the choice of experimental parameters and characterize the underlying materials physics. When the applied field is normal to the fluid layer, a checkerboard crystal forms; when the angle between the field and the normal is sufficiently large, a striped crystal assembles. As the field is slowly tilted away from the normal, we find that the transformation pathway between the two phases depends strongly on crystal orientation, field strength, and degree of confinement of the monolayer. In some cases, the pathway occurs by smooth magnetostrictive shear, while in others it involves the sudden formation of martensitic plates. PMID:25677504

Yang, Ye; Fu, Lin; Marcoux, Catherine; Socolar, Joshua E S; Charbonneau, Patrick; Yellen, Benjamin B

2015-03-11

429

Generalization of Conformal Transformations  

E-print Network

Conformal transformations of a Euclidean (complex) plane have some kind of completeness (sufficiency) for the solution of many mathematical and physical-mathematical problems formulated on this plane. There is no such completeness in the case of Euclidean, pseudo-Euclidean and polynumber spaces of dimension greater than two. In the present paper we show that using the concepts of analogical geometries allows us to generalize conformal transformations not only to the case of Euclidean or pseudo-Euclidean spaces, but also to the case of Finsler spaces, analogous to the spaces of affine connectedness. Examples of such transformations in the case of complex and hypercomplex numbers H_4 are presented. In the general case such transformations form a group of transitions, the elements of which can be viewed as transitions between projective Euclidean geometries of a distinguished class fixed by the choice of metric geometry admitting affine coordinates. The correlation between functions realizing generalized conformal transformations and generalized analytical functions can appear to be productive for the solution of fundamental problems in theoretical and mathematical physics.

G. I. Garas'ko

2005-09-19

430

Contact transformations for difference schemes  

E-print Network

We define a class of transformations of the dependent and independent variables in an ordinary difference scheme. The transformations leave the solution set of the system invariant and reduces to a group of contact transformations in the continuous limit. We use a simple example to show that the class is not empty and that such "contact transformations for discrete systems" genuinely exist.

Decio Levi; Zora Thomova; Pavel Winternitz

2011-10-15

431

Shape transformation for polyhedral objects  

Microsoft Academic Search

Techniques that transform one two-dimensionaf image into another have gained widespread use m recent yeara. Extending these tech- niques to transform pairs of 3D objects, as opposed to 2D images of the objects, providea several advsntagea, including the ability to sn- imate the objects independently of the transformation. This paper presents an algorithm for computing such transformations. The al- gorithm

James R. Kent; Wayne E. Carlson; Richard E. Parent

1992-01-01

432

Invariants of polarization transformations.  

PubMed

The use of polarization-sensitive sensors is being explored in a variety of applications. Polarization diversity has been shown to improve the performance of the automatic target detection and recognition in a significant way. However, it also brings out the problems associated with processing and storing more data and the problem of polarization distortion during transmission. We present a technique for extracting attributes that are invariant under polarization transformations. The polarimetric signatures are represented in terms of the components of the Stokes vectors. Invariant algebra is then used to extract a set of signature-related attributes that are invariant under linear transformation of the Stokes vectors. Experimental results using polarimetric infrared signatures of a number of manmade and natural objects undergoing systematic linear transformations support the invariancy of these attributes. PMID:17514238

Sadjadi, Firooz A

2007-05-20

433

Transformation inverse design.  

PubMed

We present a new technique for the design of transformation-optics devices based on large-scale optimization to achieve the optimal effective isotropic dielectric materials within prescribed index bounds, which is computationally cheap because transformation optics circumvents the need to solve Maxwell's equations at each step. We apply this technique to the design of multimode waveguide bends (realized experimentally in a previous paper) and mode squeezers, in which all modes are transported equally without scattering. In addition to the optimization, a key point is the identification of the correct boundary conditions to ensure reflectionless coupling to untransformed regions while allowing maximum flexibility in the optimization. Many previous authors in transformation optics used a certain kind of quasiconformal map which overconstrained the problem by requiring that the entire boundary shape be specified a priori while at the same time underconstraining the problem by employing "slipping" boundary conditions that permit unwanted interface reflections. PMID:23787612

Liu, David; Gabrielli, Lucas H; Lipson, Michal; Johnson, Steven G

2013-06-17

434

Transformational plasmon optics.  

PubMed

We propose and demonstrate efficiently molding surface plasmon polaritons (SPPs) based on transformation optics. SPPs are surface modes of electromagnetic waves tightly bound at metal-dielectric interfaces, which allow us to scale optics beyond the diffraction limit. Taking advantage of transformation optics, here we show that the propagation of SPPs can be manipulated in a prescribed manner by careful control of the dielectric material properties adjacent to a metal. Since the metal properties are completely unaltered, this methodology provides a practical way for routing light at very small scales. For instance, our approach enables SPPs to travel at uneven and curved surfaces over a broad wavelength range, where SPPs would normally suffer significant scattering losses. In addition, a plasmonic 180 degrees waveguide bend and a plasmonic Luneburg lens with simple designs are presented. The unique design flexibility of the transformational plasmon optics introduced here may open a new door to nano optics and downscaling of photonic circuits. PMID:20465268

Liu, Yongmin; Zentgraf, Thomas; Bartal, Guy; Zhang, Xiang

2010-06-01

435

Plastid transformation in eggplant.  

PubMed

Eggplant (Solanum melongena L.) is an important vegetable crop of tropical and temperate regions of the world. Here we describe a procedure for eggplant plastid transformation, which involves preparation of explants, biolistic delivery of plastid transformation vector into green stem segments, selection procedure, and identification of the transplastomic plants. Shoot buds appear from cut ends of the stem explants following 5-6 weeks of spectinomycin selection after bombardment with the plastid transformation vector containing aadA gene as selectable marker. Transplastomic lines are obtained after the regenerated shoots are subjected to several rounds of spectinomycin selection over a period of 9 weeks. Homoplasmic transplastomic lines are further confirmed by spectinomycin and streptomycin double selection. The transplastomic technology development in this plant species will open up exciting possibilities for improving crop performance, metabolic engineering, and the use of plants as factories for producing biopharmaceuticals. PMID:24599862

Bansal, Kailash C; Singh, Ajay K

2014-01-01

436

Transformation based endorsement systems  

NASA Technical Reports Server (NTRS)

Evidential reasoning techniques classically represent support for a hypothesis by a numeric value or an evidential interval. The combination of support is performed by an arithmetic rule which often requires restrictions to be placed on the set of possibilities. These assumptions usually require the hypotheses to be exhausitive and mutually exclusive. Endorsement based classification systems represent support for the alternatives symbolically rather than numerically. A framework for constructing endorsement systems is presented in which transformations are defined to generate and update the knowledge base. The interaction of the knowledge base and transformations produces a non-monotonic reasoning system. Two endorsement based reasoning systems are presented to demonstrate the flexibility of the transformational approach for reasoning with ambiguous and inconsistent information.

Sudkamp, Thomas

1988-01-01

437

Toothpicks and Transformations  

NSDL National Science Digital Library

In this math lesson, learners explore transformations and quadratic functions through toothpick patterns. Learners examine the mathematical pattern that emerges as they build a geometric design with toothpicks. The pattern is quadratic, and the learners determine the mathematical model in several different forms. Learners investigate the recursive nature of the relationship. An explicit model for the relation is developed, and a third model is developed by examining the scatterplot and determining the equation from the transformations. Finally, the group uses graphing calculators to develop another model and to verify that all of the models--factored form, vertex form, and general form--are equivalent.

PBS

2012-01-01

438

Genetic Transformation of Switchgrass  

NASA Astrophysics Data System (ADS)

Switchgrass (Panicum virgatum L.) is a highly productive warm-season C4 species that is being developed into a dedicated biofuel crop. This chapter describes a protocol that allows the generation of transgenic switchgrass plants by Agrobacterium tumefaciens-mediated transformation. Embryogenic calluses induced from caryopses or inflorescences were used as explants for inoculation with A. tumefaciens strain EHA105. Hygromycin phosphotransferase gene (hph) was used as the selectable marker and hygromycin was used as the selection agent. Calluses resistant to hygromycin were obtained after 5-6 weeks of selection. Soil-grown switchgrass plants were regenerated about 6 months after callus induction and Agrobacterium-mediated transformation.

Xi, Yajun; Ge, Yaxin; Wang, Zeng-Yu

439

Coordinate transformations in quaternion spaces  

E-print Network

The quaternion spaces can be used to describe the property of electromagnetic field and gravitational field. In the quaternion space, some coordinate transformations can be deduced from the feature of quaternions, including Lorentz transformation and Galilean transformation etc., when the coordinate system is transformed into others. And some coordinate transformations with variable speed of light can be obtained in the electromagnetic field and gravitational field.

Zihua Weng

2009-05-15

440

Physical characterization of cadmium telluride/cadmium sulfide photovoltaics: Defects, fields, and micrononuniformities  

NASA Astrophysics Data System (ADS)

Recent advances in large area thin-film photovoltaic manufacturing have raised a number of problems related to the physical parameters and processes behind the device efficiency and stability. The characteristics of interest include the defect spectra and related optical absorption, the built-in electric field distribution, the degree of lateral uniformity of the device, and the device stability. Established in this thesis is a set of techniques appropriate for the physical characterization of the above features in CdTe/CdS solar cells, addressing the issues of device spectra vs. energy (as revealed in the optical absorption, photoluminescence (PL), and admittance spectroscopy); the electric field distribution analyzed by means of bias dependent PL, and, indirectly, by capacitance measurements; device lateral resistivity and uniformity, through the phenomenon of nonlocal optical response and PL mapping; local parameter fluctuations as appear in virtually all of the above cases. The most important physical conclusions made are: energy spectra of polycrystalline CdTe based photovoltaics combine the features of crystalline materials, such as identifiable point defects, and amorphous materials, which exhibit continuous spectra of localized states; the concept of a single-defect (elemental) capacitance is for the first time defined and applied to estimate the density of states in polycrystalline p-n junctions; a phenomenon of bias-dependent PL in CdTe based photovoltaics is for the first time observed and modeled; a new phenomenon of nonlocal photovoltaic response is observed and interpreted. The results suggest several practical applications, such as: absorption and PL measurements as a diagnostic tool for monitoring the CdCl2, quality of treatments; admittance spectroscopy techniques to diagnose the material quality and degradation through its defect spectra and concentration; bias-dependent PL as a sensitive nondestructive accelerated life testing tool; nonlocal PV response as a transparent contact diagnostic tool in a finished device.

Shvydka, Diana

441

Characterization of the semi-insulating properties of AlHfO3.5 for power devices  

NASA Astrophysics Data System (ADS)

Physical and electrical characterization of hafnium aluminates gate dielectrics was carried out to investigate their semi-insulating characteristics as passivating layer for power devices. The deposited films were annealed in pure nitrogen to simulate the thermal budget during a conventional CMOS processing. C-V measurements were performed having as a result a high-frequency behavior of the flat band voltage (VFB) and values greater than or equal to zero. On the other hand, the leakage phenomenon was modeled with a simplified electrical model using a leakage admittance YC whose influence was predominant at the accumulation region. Using X-ray reflectometry (XRR), the average thickness obtained was 15.5nm and a leakage process was inferred to occur for AlHfO3.5 due to the observed phase separation and crystallization that occurs after annealing in pure N2.

Alandia, B. S.; Huanca, D. R.; Christiano, V.; dos Santos Filho, S. G.

2015-03-01

442

Transforming Data into Knowledge  

ERIC Educational Resources Information Center

School systems can be data rich and information poor if they do not understand and manage their data effectively. The task for school leaders is to put existing data into a format that lends itself to answering questions and improving outcomes for the students. Common barriers to transforming data into knowledge in education settings often include…

Mills, Lane

2006-01-01

443

Breakdown of Transformer Oil  

Microsoft Academic Search

Breakdown of transformer oil is affected not only by electrostatic field configurations, but also by many other factors. The latters make it difficult to predict break- down voltage from electrostatic field, as made for air and S F6 gaps. Alternatively, many experimenters tried to express the breakdown stress of oil as a function of stressed oil volume. But, results are

Y. Kawaguchi; H. Murata; M. Ikeda

1972-01-01

444

Computerized toroidal transformer design  

NASA Technical Reports Server (NTRS)

Computer program designs transformers which have one primary /center tap permissible/ and up to 20 untapped secondaries, and which can handle up to 500 V across any one winding. Computer determines total secondary power, core type, primary turns, secondary turns, and wire sizes for primary and secondary windings.

1970-01-01

445

Breakdown of transformer oil  

Microsoft Academic Search

Some of the factors affecting the dielectric strength of transformer oil are investigated. These factors include the stabilization phenomenon, oil and electrode pretreatment, the effect of oil velocity, the effect of a capacitance parallel to the test cell, and the effects of electrode area and gap spacing. The experimental apparatus and procedure are described, and the results are presented for

M. G. Danikas

1990-01-01

446

Multiband cyclic wavelet transforms  

Microsoft Academic Search

Multiresolution analysis via decomposition into wavelets has been established as an important transform technique in signal processing. A wealth of results is available on this subject, the framework has been extended to treat finite length sequences of size 2n (for positive integers n) over finite fields. The paper extends this idea further to provide a framework for dealing with data

Sandip Sarkar; H. V. Poor

1996-01-01

447

Function Transformation without Reinforcement  

ERIC Educational Resources Information Center

In studies of function transformation, participants initially are taught to match stimuli in the presence of a contextual cue, X; the stimuli to be matched bear some formal relation to each other, for example, a relation of opposition or difference. In a second phase, the participants are taught to match arbitrary stimuli (say, A and B) in the…

Tonneau, Francois; Arreola, Fara; Martinez, Alma Gabriela

2006-01-01

448

Fixture for winding transformers  

NASA Technical Reports Server (NTRS)

Bench-mounted fixture assists operator in winding toroid-shaped transformer cores. Toroid is rigidly held in place as wires are looped around. Arrangement frees both hands for rapid winding and untangling of wires that occurs when core is hand held.

Mclyman, M. T.

1980-01-01

449

Transformer Impedance Reflection Demonstration  

ERIC Educational Resources Information Center

Questions often arise as to how a device attached to a transformer can draw power from the electrical power grid since it seems that the primary and secondary are not connected to one another. However, a closer look at how the primary and secondary are linked together magnetically and a consideration of the role of Lenz's law in this linkage…

Layton, William

2014-01-01

450

Transformer and Meter Tester  

NASA Technical Reports Server (NTRS)

Numerically-controlled 5-axis machine tool uses transformer and meter to determine and indicate whether tool is in home position, but lacks built-in test mode to check them. Tester makes possible test, and repair of components at machine rather then replace them when operation seems suspect.

Stoms, R. M.

1984-01-01

451

Leading System Transformation  

ERIC Educational Resources Information Center

This article outlines progress made towards education transformation in Wales. It explores the way in which tri-level reform is guiding system level change in Wales and looks at the implementation of the School Effectiveness Framework, which is at the heart of the reform process. It describes the way in which professional learning communities are…

Harris, Alma

2010-01-01

452

Review article Genetic transformation  

E-print Network

Review article Genetic transformation: a short review of methods and their applications, results — This report reviews the state-of-the-art in plant genetic engineering, covering both di- rect and indirect gene transfer methods. The application of these techniques to forest trees has been discussed

Paris-Sud XI, Université de

453

Transformations: Translation (NLVM)  

NSDL National Science Digital Library

This Java applet enables learners to explore the translation transformation (sliding) both informally and within a coordinate system. Students select and compose shapes and manipulate the ends of a translation vector to see the effect on a translated image. Links to instructions, activities and teacher/parent information are included.

2011-01-01

454

Transformations: Reflection (NLVM)  

NSDL National Science Digital Library

This Java applet enables learners to explore the reflection transformation both informally and within a coordinate system. Students select and compose shapes and manipulate the axis of symmetry (the mirror) to see the effect on a reflected image. Links to instructions, activities and teacher/parent information are included.

2011-01-01

455

Transformations: Rotation (NLVM)  

NSDL National Science Digital Library

This Java applet enables learners to explore the rotation transformation both informally and within a coordinate system. Students select and compose shapes and manipulate the center and angle of rotation to see the effect on a rotated image. Links to instructions, activities and teacher/parent information are included.

2011-01-01

456

Fourier Transform Mass Spectrometry.  

ERIC Educational Resources Information Center

Discusses the nature of Fourier transform mass spectrometry and its unique combination of high mass resolution, high upper mass limit, and multichannel advantage. Examines its operation, capabilities and limitations, applications (ion storage, ion manipulation, ion chemistry), and future applications and developments. (JN)

Gross, Michael L.; Rempel, Don L.

1984-01-01

457

Transformation Problem Solving Abilities.  

ERIC Educational Resources Information Center

The relationship between transformation problem performance and Guilford Structure of Intellect (SI) abilities is explored. During two group sessions 42 females and 35 males, age 18-39, were administered 12 Guilford SI tests exemplifying all five symbolic content (numeric) operations, and three contents in the divergent production area. Logical…

Harmel, Sarah Jane

458

An Introductory Transformational Grammar.  

ERIC Educational Resources Information Center

The present volume is directed toward the reader wanting to begin a study of linguistics but who is "overwhelmed by the amount of material available, much of it too technical for him to understand." The author has attempted to provide both theory and applications and has limited the scope to English transformational grammar. Exercises at the end…

Liles, Bruce L.

459

Beyond Reform: Transformation  

ERIC Educational Resources Information Center

The Coalition of Essential Schools (CES) is not a reform movement. To reform is to make a thing again; reformation implies a stasis that doesn't deliver enough for the educational future. This issue of Horace demonstrates that Essential schools and the districts and networks that support them are at various points in the journey of transformation,…

Davidson, Jill

2007-01-01

460

TO TRANSFORM BIOMEDICAL ENGINEERING  

E-print Network

of people suffering from congestive heart failure. His device fits around the heart and restores properIT'S TIME TO TRANSFORM BIOMEDICAL ENGINEERING EDUCATION #12;Charles H. & Bettye Barclay Professor in biomedical engineering research and education ­ and we're well on our way. Our faculty continues to engineer