Correcting for variable laser-target distances of laser-induced breakdown spectroscopy measurements with ChemCam using emission lines of Martian dust spectra

Energy Technology Data Exchange (ETDEWEB)

Melikechi, N.; Mezzacappa, A. [Optical Science Center for Applied Research, Delaware State University, Dover, DE (United States); Cousin, A.; Lanza, N.L. [Los Alamos National Laboratory, Los Alamos, NM (United States); Lasue, J. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Clegg, S.M. [Los Alamos National Laboratory, Los Alamos, NM (United States); Berger, G. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Wiens, R.C. [Los Alamos National Laboratory, Los Alamos, NM (United States); Maurice, S. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Tokar, R.L.; Bender, S. [Planetary Science Institute, Flagstaff, AZ (United States); Forni, O. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Breves, E.A.; Dyar, M.D. [Dept. of Astronomy, Mount Holyoke College, South Hadley, MA (United States); Frydenvang, J. [The Niels Bohr Institute, University of Copenhagen, Copenhagen (Denmark); Delapp, D. [Los Alamos National Laboratory, Los Alamos, NM (United States); Gasnault, O. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Newsom, H.; Ollila, A.M. [Earth and Planetary Sciences, University of New Mexico, Alburquerque, NM (United States); Lewin, E. [Institut des Sciences de la Terre, Universite Grenoble l-CNRS, Grenoble (France); and others

2014-06-01

As part of the Mars Science Laboratory, the ChemCam instrument acquires remote laser induced breakdown spectra at distances that vary between 1.56 m and 7 m. This variation in distance affects the intensities of the measured LIBS emission lines in non-trivial ways. To determine the behavior of a LIBS emission line with distance, it is necessary to separate the effects of many parameters such as laser energy, laser spot size, target homogeneity, and optical collection efficiency. These parameters may be controlled in a laboratory on Earth but for field applications or in space this is a challenge. In this paper, we show that carefully selected ChemCam LIBS emission lines acquired from the Martian dust can be used to build an internal proxy spectroscopic standard. This in turn, allows for a direct measurement of the effects of the distance of various LIBS emission lines and hence can be used to correct ChemCam LIBS spectra for distance variations. When tested on pre-launch LIBS calibration data acquired under Martian-like conditions and with controlled and well-calibrated targets, this approach yields much improved agreement between targets observed at various distances. This work lays the foundation for future implementation of automated routines to correct ChemCam spectra for differences caused by variable distance. - Highlights: • Selected Martian dust emission lines are used to correct for variable laser-target distances. • The correction model yields improved agreement between targets observed at various distances. • The impact of the model reduces the bias between predicted and actual compositions by as much as 70%. • When implemented, the model will yield spectral corrections for various ChemCam measurements. • This work is a foundation to perform novel stand-off LIBS measurements on Earth and other planets.

A Distance Measure for Genome Phylogenetic Analysis

Science.gov (United States)

Cao, Minh Duc; Allison, Lloyd; Dix, Trevor

Phylogenetic analyses of species based on single genes or parts of the genomes are often inconsistent because of factors such as variable rates of evolution and horizontal gene transfer. The availability of more and more sequenced genomes allows phylogeny construction from complete genomes that is less sensitive to such inconsistency. For such long sequences, construction methods like maximum parsimony and maximum likelihood are often not possible due to their intensive computational requirement. Another class of tree construction methods, namely distance-based methods, require a measure of distances between any two genomes. Some measures such as evolutionary edit distance of gene order and gene content are computational expensive or do not perform well when the gene content of the organisms are similar. This study presents an information theoretic measure of genetic distances between genomes based on the biological compression algorithm expert model. We demonstrate that our distance measure can be applied to reconstruct the consensus phylogenetic tree of a number of Plasmodium parasites from their genomes, the statistical bias of which would mislead conventional analysis methods. Our approach is also used to successfully construct a plausible evolutionary tree for the γ-Proteobacteria group whose genomes are known to contain many horizontally transferred genes.

Underwater near-infrared spectroscopy can measure training adaptations in adolescent swimmers

OpenAIRE

Ben Jones; Dave Parry; Chris E. Cooper

2018-01-01

The development of an underwater near-infrared spectroscopy (uNIRS) device has enabled previously unattainable measurements of peripheral muscle hemodynamics and oxygenation to be taken within the natural aquatic environment. The purposes of this study were (i) to trial the use of uNIRS, in a real world training study, and (ii) to monitor the effects of a swim training program upon muscle oxygenation status in short distance swimming. A total of 14 junior club level swimmers completed a repea...

Measuring distances between complex networks

International Nuclear Information System (INIS)

Andrade, Roberto F.S.; Miranda, Jose G.V.; Pinho, Suani T.R.; Lobao, Thierry Petit

2008-01-01

A previously introduced concept of higher order neighborhoods in complex networks, [R.F.S. Andrade, J.G.V. Miranda, T.P. Lobao, Phys. Rev. E 73 (2006) 046101] is used to define a distance between networks with the same number of nodes. With such measure, expressed in terms of the matrix elements of the neighborhood matrices of each network, it is possible to compare, in a quantitative way, how far apart in the space of neighborhood matrices two networks are. The distance between these matrices depends on both the network topologies and the adopted node numberings. While the numbering of one network is fixed, a Monte Carlo algorithm is used to find the best numbering of the other network, in the sense that it minimizes the distance between the matrices. The minimal value found for the distance reflects differences in the neighborhood structures of the two networks that arise only from distinct topologies. This procedure ends up by providing a projection of the first network on the pattern of the second one. Examples are worked out allowing for a quantitative comparison for distances among distinct networks, as well as among distinct realizations of random networks

Single-Image Distance Measurement by a Smart Mobile Device.

Science.gov (United States)

Chen, Shangwen; Fang, Xianyong; Shen, Jianbing; Wang, Linbo; Shao, Ling

2017-12-01

Existing distance measurement methods either require multiple images and special photographing poses or only measure the height with a special view configuration. We propose a novel image-based method that can measure various types of distance from single image captured by a smart mobile device. The embedded accelerometer is used to determine the view orientation of the device. Consequently, pixels can be back-projected to the ground, thanks to the efficient calibration method using two known distances. Then the distance in pixel is transformed to a real distance in centimeter with a linear model parameterized by the magnification ratio. Various types of distance specified in the image can be computed accordingly. Experimental results demonstrate the effectiveness of the proposed method.

Distance Measurement Solves Astrophysical Mysteries

Science.gov (United States)

2003-08-01

Location, location, and location. The old real-estate adage about what's really important proved applicable to astrophysics as astronomers used the sharp radio "vision" of the National Science Foundation's Very Long Baseline Array (VLBA) to pinpoint the distance to a pulsar. Their accurate distance measurement then resolved a dispute over the pulsar's birthplace, allowed the astronomers to determine the size of its neutron star and possibly solve a mystery about cosmic rays. "Getting an accurate distance to this pulsar gave us a real bonanza," said Walter Brisken, of the National Radio Astronomy Observatory (NRAO) in Socorro, NM. Monogem Ring The Monogem Ring, in X-Ray Image by ROSAT satellite CREDIT: Max-Planck Institute, American Astronomical Society (Click on Image for Larger Version) The pulsar, called PSR B0656+14, is in the constellation Gemini, and appears to be near the center of a circular supernova remnant that straddles Gemini and its neighboring constellation, Monoceros, and is thus called the Monogem Ring. Since pulsars are superdense, spinning neutron stars left over when a massive star explodes as a supernova, it was logical to assume that the Monogem Ring, the shell of debris from a supernova explosion, was the remnant of the blast that created the pulsar. However, astronomers using indirect methods of determining the distance to the pulsar had concluded that it was nearly 2500 light-years from Earth. On the other hand, the supernova remnant was determined to be only about 1000 light-years from Earth. It seemed unlikely that the two were related, but instead appeared nearby in the sky purely by a chance juxtaposition. Brisken and his colleagues used the VLBA to make precise measurements of the sky position of PSR B0656+14 from 2000 to 2002. They were able to detect the slight offset in the object's apparent position when viewed from opposite sides of Earth's orbit around the Sun. This effect, called parallax, provides a direct measurement of

Femtosecond frequency comb based distance measurement in air

NARCIS (Netherlands)

Balling, P.; Kren, P.; Masika, P.; van den Berg, S.A.

2009-01-01

Interferometric measurement of distance using a femtosecond frequency comb is demonstrated and compared with a counting interferometer displacement measurement. A numerical model of pulse propagation in air is developed and the results are compared with experimental data for short distances. The

A cognitively grounded measure of pronunciation distance.

Directory of Open Access Journals (Sweden)

Martijn Wieling

Full Text Available In this study we develop pronunciation distances based on naive discriminative learning (NDL. Measures of pronunciation distance are used in several subfields of linguistics, including psycholinguistics, dialectology and typology. In contrast to the commonly used Levenshtein algorithm, NDL is grounded in cognitive theory of competitive reinforcement learning and is able to generate asymmetrical pronunciation distances. In a first study, we validated the NDL-based pronunciation distances by comparing them to a large set of native-likeness ratings given by native American English speakers when presented with accented English speech. In a second study, the NDL-based pronunciation distances were validated on the basis of perceptual dialect distances of Norwegian speakers. Results indicated that the NDL-based pronunciation distances matched perceptual distances reasonably well with correlations ranging between 0.7 and 0.8. While the correlations were comparable to those obtained using the Levenshtein distance, the NDL-based approach is more flexible as it is also able to incorporate acoustic information other than sound segments.

Distance measurement using frequency scanning interferometry with mode-hoped laser

Science.gov (United States)

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

2016-06-01

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

Measures of lexical distance between languages

Science.gov (United States)

Petroni, Filippo; Serva, Maurizio

2010-06-01

The idea of measuring distance between languages seems to have its roots in the work of the French explorer Dumont D’Urville (1832) [13]. He collected comparative word lists for various languages during his voyages aboard the Astrolabe from 1826 to 1829 and, in his work concerning the geographical division of the Pacific, he proposed a method for measuring the degree of relation among languages. The method used by modern glottochronology, developed by Morris Swadesh in the 1950s, measures distances from the percentage of shared cognates, which are words with a common historical origin. Recently, we proposed a new automated method which uses the normalized Levenshtein distances among words with the same meaning and averages on the words contained in a list. Recently another group of scholars, Bakker et al. (2009) [8] and Holman et al. (2008) [9], proposed a refined version of our definition including a second normalization. In this paper we compare the information content of our definition with the refined version in order to decide which of the two can be applied with greater success to resolve relationships among languages.

An adaptive distance measure for use with nonparametric models

International Nuclear Information System (INIS)

Garvey, D. R.; Hines, J. W.

2006-01-01

Distance measures perform a critical task in nonparametric, locally weighted regression. Locally weighted regression (LWR) models are a form of 'lazy learning' which construct a local model 'on the fly' by comparing a query vector to historical, exemplar vectors according to a three step process. First, the distance of the query vector to each of the exemplar vectors is calculated. Next, these distances are passed to a kernel function, which converts the distances to similarities or weights. Finally, the model output or response is calculated by performing locally weighted polynomial regression. To date, traditional distance measures, such as the Euclidean, weighted Euclidean, and L1-norm have been used as the first step in the prediction process. Since these measures do not take into consideration sensor failures and drift, they are inherently ill-suited for application to 'real world' systems. This paper describes one such LWR model, namely auto associative kernel regression (AAKR), and describes a new, Adaptive Euclidean distance measure that can be used to dynamically compensate for faulty sensor inputs. In this new distance measure, the query observations that lie outside of the training range (i.e. outside the minimum and maximum input exemplars) are dropped from the distance calculation. This allows for the distance calculation to be robust to sensor drifts and failures, in addition to providing a method for managing inputs that exceed the training range. In this paper, AAKR models using the standard and Adaptive Euclidean distance are developed and compared for the pressure system of an operating nuclear power plant. It is shown that using the standard Euclidean distance for data with failed inputs, significant errors in the AAKR predictions can result. By using the Adaptive Euclidean distance it is shown that high fidelity predictions are possible, in spite of the input failure. In fact, it is shown that with the Adaptive Euclidean distance prediction

Comparative evaluation of ultrasound scanner accuracy in distance measurement

Science.gov (United States)

Branca, F. P.; Sciuto, S. A.; Scorza, A.

2012-10-01

The aim of the present study is to develop and compare two different automatic methods for accuracy evaluation in ultrasound phantom measurements on B-mode images: both of them give as a result the relative error e between measured distances, performed by 14 brand new ultrasound medical scanners, and nominal distances, among nylon wires embedded in a reference test object. The first method is based on a least squares estimation, while the second one applies the mean value of the same distance evaluated at different locations in ultrasound image (same distance method). Results for both of them are proposed and explained.

Shape anisotropy: tensor distance to anisotropy measure

Science.gov (United States)

Weldeselassie, Yonas T.; El-Hilo, Saba; Atkins, M. S.

2011-03-01

Fractional anisotropy, defined as the distance of a diffusion tensor from its closest isotropic tensor, has been extensively studied as quantitative anisotropy measure for diffusion tensor magnetic resonance images (DT-MRI). It has been used to reveal the white matter profile of brain images, as guiding feature for seeding and stopping in fiber tractography and for the diagnosis and assessment of degenerative brain diseases. Despite its extensive use in DT-MRI community, however, not much attention has been given to the mathematical correctness of its derivation from diffusion tensors which is achieved using Euclidean dot product in 9D space. But, recent progress in DT-MRI has shown that the space of diffusion tensors does not form a Euclidean vector space and thus Euclidean dot product is not appropriate for tensors. In this paper, we propose a novel and robust rotationally invariant diffusion anisotropy measure derived using the recently proposed Log-Euclidean and J-divergence tensor distance measures. An interesting finding of our work is that given a diffusion tensor, its closest isotropic tensor is different for different tensor distance metrics used. We demonstrate qualitatively that our new anisotropy measure reveals superior white matter profile of DT-MR brain images and analytically show that it has a higher signal to noise ratio than fractional anisotropy.

Long distance measurement with a femtosecond laser based frequency comb

Science.gov (United States)

Bhattacharya, N.; Cui, M.; Zeitouny, M. G.; Urbach, H. P.; van den Berg, S. A.

2017-11-01

Recent advances in the field of ultra-short pulse lasers have led to the development of reliable sources of carrier envelope phase stabilized femtosecond pulses. The pulse train generated by such a source has a frequency spectrum that consists of discrete, regularly spaced lines known as a frequency comb. In this case both the frequency repetition and the carrier-envelope-offset frequency are referenced to a frequency standard, like an atomic clock. As a result the accuracy of the frequency standard is transferred to the optical domain, with the frequency comb as transfer oscillator. These unique properties allow the frequency comb to be applied as a versatile tool, not only for time and frequency metrology, but also in fundamental physics, high-precision spectroscopy, and laser noise characterization. The pulse-to-pulse phase relationship of the light emitted by the frequency comb has opened up new directions for long range highly accurate distance measurement.

Radio Astronomers Set New Standard for Accurate Cosmic Distance Measurement

Science.gov (United States)

1999-06-01

A team of radio astronomers has used the National Science Foundation's Very Long Baseline Array (VLBA) to make the most accurate measurement ever made of the distance to a faraway galaxy. Their direct measurement calls into question the precision of distance determinations made by other techniques, including those announced last week by a team using the Hubble Space Telescope. The radio astronomers measured a distance of 23.5 million light-years to a galaxy called NGC 4258 in Ursa Major. "Ours is a direct measurement, using geometry, and is independent of all other methods of determining cosmic distances," said Jim Herrnstein, of the National Radio Astronomy Observatory (NRAO) in Socorro, NM. The team says their measurement is accurate to within less than a million light-years, or four percent. The galaxy is also known as Messier 106 and is visible with amateur telescopes. Herrnstein, along with James Moran and Lincoln Greenhill of the Harvard- Smithsonian Center for Astrophysics; Phillip Diamond, of the Merlin radio telescope facility at Jodrell Bank and the University of Manchester in England; Makato Inoue and Naomasa Nakai of Japan's Nobeyama Radio Observatory; Mikato Miyoshi of Japan's National Astronomical Observatory; Christian Henkel of Germany's Max Planck Institute for Radio Astronomy; and Adam Riess of the University of California at Berkeley, announced their findings at the American Astronomical Society's meeting in Chicago. "This is an incredible achievement to measure the distance to another galaxy with this precision," said Miller Goss, NRAO's Director of VLA/VLBA Operations. "This is the first time such a great distance has been measured this accurately. It took painstaking work on the part of the observing team, and it took a radio telescope the size of the Earth -- the VLBA -- to make it possible," Goss said. "Astronomers have sought to determine the Hubble Constant, the rate of expansion of the universe, for decades. This will in turn lead to an

Evaluation of Distance Measures Between Gaussian Mixture Models of MFCCs

DEFF Research Database (Denmark)

Jensen, Jesper Højvang; Ellis, Dan P. W.; Christensen, Mads Græsbøll

2007-01-01

In music similarity and in the related task of genre classification, a distance measure between Gaussian mixture models is frequently needed. We present a comparison of the Kullback-Leibler distance, the earth movers distance and the normalized L2 distance for this application. Although...

Surface vibrational spectroscopy

International Nuclear Information System (INIS)

Erskine, J.L.

1984-01-01

A brief review of recent studies which combine measurements of surface vibrational energies with lattice dynamical calculations is presented. These results suggest that surface vibrational spectroscopy offers interesting prospects for use as a molecular-level probe of surface geometry, adsorbate bond distances and molecular orientations

Pairwise Comparison and Distance Measure of Hesitant Fuzzy Linguistic Term Sets

Directory of Open Access Journals (Sweden)

Han-Chen Huang

2014-01-01

Full Text Available A hesitant fuzzy linguistic term set (HFLTS, allowing experts using several possible linguistic terms to assess a qualitative linguistic variable, is very useful to express people’s hesitancy in practical decision-making problems. Up to now, a little research has been done on the comparison and distance measure of HFLTSs. In this paper, we present a comparison method for HFLTSs based on pairwise comparisons of each linguistic term in the two HFLTSs. Then, a distance measure method based on the pairwise comparison matrix of HFLTSs is proposed, and we prove that this distance is equal to the distance of the average values of HFLTSs, which makes the distance measure much more simple. Finally, the pairwise comparison and distance measure methods are utilized to develop two multicriteria decision-making approaches under hesitant fuzzy linguistic environments. The results analysis shows that our methods in this paper are more reasonable.

Evaluation of gene-expression clustering via mutual information distance measure

Directory of Open Access Journals (Sweden)

Maimon Oded

2007-03-01

Full Text Available Abstract Background The definition of a distance measure plays a key role in the evaluation of different clustering solutions of gene expression profiles. In this empirical study we compare different clustering solutions when using the Mutual Information (MI measure versus the use of the well known Euclidean distance and Pearson correlation coefficient. Results Relying on several public gene expression datasets, we evaluate the homogeneity and separation scores of different clustering solutions. It was found that the use of the MI measure yields a more significant differentiation among erroneous clustering solutions. The proposed measure was also used to analyze the performance of several known clustering algorithms. A comparative study of these algorithms reveals that their "best solutions" are ranked almost oppositely when using different distance measures, despite the found correspondence between these measures when analysing the averaged scores of groups of solutions. Conclusion In view of the results, further attention should be paid to the selection of a proper distance measure for analyzing the clustering of gene expression data.

Distance Measures for Information System Reengineering

NARCIS (Netherlands)

Poels, G.; Viaene, S.; Dedene, G.; Wangler, B.; Bergman, L.

2000-01-01

We present an approach to assess the magnitude and impact of information system reengineering caused by business process change. This approach is based on two concepts: object-oriented business modeling and distance measurement. The former concept is used to visualize changes in the business layer

High Precision Infrared Temperature Measurement System Based on Distance Compensation

Directory of Open Access Journals (Sweden)

Chen Jing

2017-01-01

Full Text Available To meet the need of real-time remote monitoring of human body surface temperature for optical rehabilitation therapy, a non-contact high-precision real-time temperature measurement method based on distance compensation was proposed, and the system design was carried out. The microcontroller controls the infrared temperature measurement module and the laser range module to collect temperature and distance data. The compensation formula of temperature with distance wass fitted according to the least square method. Testing had been performed on different individuals to verify the accuracy of the system. The results indicate that the designed non-contact infrared temperature measurement system has a residual error of less than 0.2°C and the response time isless than 0.1s in the range of 0 to 60cm. This provides a reference for developing long-distance temperature measurement equipment in optical rehabilitation therapy.

How to measure distance visual acuity

Directory of Open Access Journals (Sweden)

Janet Marsden

2014-04-01

Full Text Available Visual acuity (VA is a measure of the ability of the eye to distinguish shapes and the details of objects at a given distance. It is important to assess VA in a consistent way in order to detect any changes in vision. One eye is tested at a time.

A Novel Method for Short Distance Measurements

International Nuclear Information System (INIS)

Fernandez, M.G.; Ferrando, A.; Josa, M.I.; Molinero, A.; Oller, J.C.; Arce, P.; Calvo, E.; Figueroa, C.F.; Garcia, C.F.; Rodigrido, T.; Vila, I.; Virto, A.L.

1998-01-01

A new, accurate and un expensive device for measuring short distances, intended for monitoring in LHC experiments is presented. Data taken with a very simple prototype are shown and performance is extracted. (Author) 4 refs

Recoil distance lifetime measurements in 122,124Xe

Science.gov (United States)

Govil, I. M.; Kumar, A.; Iyer, H.; Li, H.; Garg, U.; Ghugre, S. S.; Johnson, T.; Kaczarowski, R.; Kharraja, B.; Naguleswaran, S.; Walpe, J. C.

1998-02-01

Lifetimes of the lower-excited states in 122,124Xe are measured using the recoil-distance Doppler-shift technique. The reactions 110Pd(16O,4n)122Xe and 110Pd(18O,4n)124Xe at a beam energy of 66 MeV were used for this experiment. The lifetimes of the 2+, 4+, 6+, and 8+ states of the ground state band were extracted using the computer code LIFETIME including the corrections due to the side feeding and the nuclear deorientation effects. The lifetime of the 2+ state in 122Xe agrees with the recoil distance method (RDM) measurements but for the 124Xe it does not agree with the RDM measurements but agrees with the Coulomb-excitation experiment. The measured B(E2) values for both the nuclei are compared with the standard algebraic and the multishell models.

Measuring sidewalk distances using Google Earth

Directory of Open Access Journals (Sweden)

Janssen Ian

2012-03-01

Full Text Available Abstract Background Physical activity is an important determinant of health. Walking is the most common physical activity performed by adults and the presence of sidewalks along roads is a determinant of walking. Geographic information systems (GIS can be used to measure sidewalks; however, GIS sidewalk data are difficult to access. The purpose of this study was to present a new GIS method for measuring the distance and coverage of sidewalks along roadways. Methods The new method contains three stages. Stage 1 involves calculating the distance of all road segments within the region of interest (e.g., neighborhood, extracting geospatial information on these road segments, and saving this information as a Google Earth file. This stage was performed in ArcGIS software. Stage 2 involves opening the extracted road segment geospatial data in Google Earth, visually examining road segments to see if they contain sidewalks, and deleting road segments without sidewalks. Stage 3 involves importing the modified road geospatial data into ArcGIS and calculating the length of road segments with sidewalks. The new method was tested in 315 sites across Canada. Each site consisted of a one km radius circular buffer surrounding a school. Results A detailed, step-by-step protocol is provided in the paper. The length of road segments with sidewalks in the testing sites ranged from 0.00 to 55.05 km (median 16.20 km. When expressed relative to the length of all road segments, the length of road segments with sidewalks ranged from 0% to 100% (median 53%. By comparison to urban testing sites, rural sites had shorter sidewalk lengths and a smaller proportion of the roads had sidewalk coverage. Conclusion This study provides a new GIS protocol that researchers can use to measure the distance and coverage of sidewalks along roadways.

Ultrasound measurement of transcranial distance during head-down tilt

Science.gov (United States)

Torikoshi, S.; Wilson, M. H.; Ballard, R. E.; Watenpaugh, D. E.; Murthy, G.; Yost, W. T.; Cantrell, J. H.; Chang, D. S.; Hargens, A. R.

1995-01-01

Exposure to microgravity elevates blood pressure and flow in the head, which may increase intracranial volume (ICV) and intracranial pressure (ICP). Rhesus monkeys exposed to simulated microgravity in the form of 6 degree head-down tilt (HDT) experience elevated ICP. With humans, twenty-four hours of 6 degree HDT bed rest increases cerebral blood flow velocity relative to pre-HDT upright posture. Humans exposed to acute 6 degree HDT experiments increased ICP, measured with the tympanic membrane displacement (TMD) technique. Other studies suggest that increased ICP in humans and cats causes measurable cranial bone movement across the sagittal suture. Due to the slightly compliant nature of the cranium, elevation of the ICP will increase ICV and transcranial distance. Currently, several non-invasive approaches to monitor ICP are being investigated. Such techniques include TMD and modal analysis of the skull. TMD may not be reliable over a large range of ICP and neither method is capable of measuring the small changes in pressure. Ultrasound, however, may reliably measure small distance changes that accompany ICP fluctuations. The purpose of our study was to develop and evaluate an ultrasound technique to measure transcranial distance changes during HDT.

An Introduction to Distance Measurement in Astronomy

CERN Document Server

de Grijs, Richard

2011-01-01

Distance determination is an essential technique in astronomy, and is briefly covered in most textbooks on astrophysics and cosmology. It is rarely covered as a coherent topic in its own right. When it is discussed the approach is frequently very dry, splitting the teaching into, for example, stars, galaxies and cosmologies, and as a consequence, books lack depth and are rarely comprehensive. Adopting a unique and engaging approach to the subject An Introduction to distance Measurement in Astronomy will take the reader on a journey from the solar neighbourhood to the edge of the Universe, dis

Study on the effect of beam propagation through atmospheric turbulence on standoff nanosecond laser induced breakdown spectroscopy measurements.

Science.gov (United States)

Laserna, J J; Reyes, R Fernández; González, R; Tobaria, L; Lucena, P

2009-06-08

We report on an experimental study of the effect of atmospheric turbulence on laser induced breakdown spectroscopy (LIBS) measurements. The characteristics of the atmosphere dictate specific performance constraints to this technology. Unlike classical laboratory LIBS systems where the distance to the sample is well known and characterized, LIBS systems working at several tens of meters to the target have specific atmospheric propagation conditions that cause the quality of the LIBS signals to be affected to a significant extent. Using a new LIBS based sensor system fitted with a nanosecond laser emitting at 1064 nm, propagation effects at distances of up to 120 m were investigated. The effects observed include wander and scintillation in the outgoing laser beam and in the return atomic emission signal. Plasmas were formed on aluminium targets. Average signal levels and signal fluctuations are measured so the effect of atmospheric turbulence on LIBS measurements is quantified.

Underwater near-infrared spectroscopy can measure training adaptations in adolescent swimmers.

Science.gov (United States)

Jones, Ben; Parry, Dave; Cooper, Chris E

2018-01-01

The development of an underwater near-infrared spectroscopy (uNIRS) device has enabled previously unattainable measurements of peripheral muscle hemodynamics and oxygenation to be taken within the natural aquatic environment. The purposes of this study were (i) to trial the use of uNIRS, in a real world training study, and (ii) to monitor the effects of a swim training program upon muscle oxygenation status in short distance swimming. A total of 14 junior club level swimmers completed a repeated swim sprint test before and after an eight week endurance training program. A waterproof, portable Near-Infrared Spectroscopy device was attached to the vastus lateralis . uNIRS successfully measured changes in muscle oxygenation and blood volume in all individuals; rapid sub-second time resolution of the device was able to demonstrate muscle oxygenation changes during the characteristic swim movements. Post training heart rate recovery and swim performance time were significantly improved. uNIRS data also showed significant changes. A larger rise in deoxyhemoglobin during individual sprints suggested training induced an increase in muscle oxygen extraction; a faster recovery time for muscle oxygenation suggested positive training induced changes and significant changes in muscle blood flow also occur. As a strong correlation was seen between an increased reoxygenation rate and an improved swim performance time, these findings support the use of uNIRS as a new performance analysis tool in swimming.

Dynamic frequency-domain interferometer for absolute distance measurements with high resolution

International Nuclear Information System (INIS)

Weng, Jidong; Liu, Shenggang; Ma, Heli; Tao, Tianjiong; Wang, Xiang; Liu, Cangli; Tan, Hua

2014-01-01

A unique dynamic frequency-domain interferometer for absolute distance measurement has been developed recently. This paper presents the working principle of the new interferometric system, which uses a photonic crystal fiber to transmit the wide-spectrum light beams and a high-speed streak camera or frame camera to record the interference stripes. Preliminary measurements of harmonic vibrations of a speaker, driven by a radio, and the changes in the tip clearance of a rotating gear wheel show that this new type of interferometer has the ability to perform absolute distance measurements both with high time- and distance-resolution

Dynamic frequency-domain interferometer for absolute distance measurements with high resolution

Science.gov (United States)

Weng, Jidong; Liu, Shenggang; Ma, Heli; Tao, Tianjiong; Wang, Xiang; Liu, Cangli; Tan, Hua

2014-11-01

A unique dynamic frequency-domain interferometer for absolute distance measurement has been developed recently. This paper presents the working principle of the new interferometric system, which uses a photonic crystal fiber to transmit the wide-spectrum light beams and a high-speed streak camera or frame camera to record the interference stripes. Preliminary measurements of harmonic vibrations of a speaker, driven by a radio, and the changes in the tip clearance of a rotating gear wheel show that this new type of interferometer has the ability to perform absolute distance measurements both with high time- and distance-resolution.

A Scale Elasticity Measure for Directional Distance Function and its Dual

OpenAIRE

Valentin Zelenyuk

2011-01-01

In this paper we introduce a scale elasticity measure based on directional distance function for multi-output-multi-input technologies and explore its fundamental properties. Specifically, we derive necessary and sufficient condition for equivalence of the scale elasticity measure based on the directional distance function with the input oriented and output oriented scale elasticity measures. We also establish duality relationship between the scale elasticity measure based on the directional ...

The correction of vibration in frequency scanning interferometry based absolute distance measurement system for dynamic measurements

Science.gov (United States)

Lu, Cheng; Liu, Guodong; Liu, Bingguo; Chen, Fengdong; Zhuang, Zhitao; Xu, Xinke; Gan, Yu

2015-10-01

Absolute distance measurement systems are of significant interest in the field of metrology, which could improve the manufacturing efficiency and accuracy of large assemblies in fields such as aircraft construction, automotive engineering, and the production of modern windmill blades. Frequency scanning interferometry demonstrates noticeable advantages as an absolute distance measurement system which has a high precision and doesn't depend on a cooperative target. In this paper , the influence of inevitable vibration in the frequency scanning interferometry based absolute distance measurement system is analyzed. The distance spectrum is broadened as the existence of Doppler effect caused by vibration, which will bring in a measurement error more than 103 times bigger than the changes of optical path difference. In order to decrease the influence of vibration, the changes of the optical path difference are monitored by a frequency stabilized laser, which runs parallel to the frequency scanning interferometry. The experiment has verified the effectiveness of this method.

Calibration Base Lines for Electronic Distance Measuring Instruments (EDMI)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A calibration base line (CBL) is a precisely measured, straight-line course of approximately 1,400 m used to calibrate Electronic Distance Measuring Instruments...

Geometric model of pseudo-distance measurement in satellite location systems

Science.gov (United States)

Panchuk, K. L.; Lyashkov, A. A.; Lyubchinov, E. V.

2018-04-01

The existing mathematical model of pseudo-distance measurement in satellite location systems does not provide a precise solution of the problem, but rather an approximate one. The existence of such inaccuracy, as well as bias in measurement of distance from satellite to receiver, results in inaccuracy level of several meters. Thereupon, relevance of refinement of the current mathematical model becomes obvious. The solution of the system of quadratic equations used in the current mathematical model is based on linearization. The objective of the paper is refinement of current mathematical model and derivation of analytical solution of the system of equations on its basis. In order to attain the objective, geometric analysis is performed; geometric interpretation of the equations is given. As a result, an equivalent system of equations, which allows analytical solution, is derived. An example of analytical solution implementation is presented. Application of analytical solution algorithm to the problem of pseudo-distance measurement in satellite location systems allows to improve the accuracy such measurements.

Optical study of plasma sprayed hydroxyapatite coatings deposited at different spray distance

Science.gov (United States)

Belka, R.; Kowalski, S.; Żórawski, W.

2017-08-01

Series of hydroxyapatite (HA) coatings deposited on titanium substrate at different spray (plasma gun to workpiece) distance were investigated. The optical methods as dark field confocal microscopy, Raman/PL and UV-VIS spectroscopy were used for study the influence of deposition process on structural degradation of HA precursor. The hydroxyl group concentration was investigated by study the OH mode intensity in the Raman spectra. Optical absorption coefficients at near UV region were analyzed by Diffuse Reflectance Spectroscopy. PL intensity observed during Raman measurement was also considered as relation to defects concentration and degradation level. It was confirmed the different gunsubstrate distance has a great impact on structure of deposited HA ceramics.

Improvement of Ultrasonic Distance Measuring System

Directory of Open Access Journals (Sweden)

Jiang Yu

2018-01-01

Full Text Available This paper mainly introduces a kind of ultrasonic distance measuring system with AT89C51 single chip as the core component. The paper expounds the principle of ultrasonic sensor and ultrasonic ranging, hardware circuit and software program, and the results of experiment and analysis.The hardware circuit based on SCM, the software design adopts the advanced microcontroller programming language.The amplitude of the received signal and the time of ultrasonic propagation are regulated by closed loop control. [1,2]The double closed loop control technology for amplitude and time improves the measuring accuracy of the instrument. The experimental results show that greatly improves the measurement accuracy of the system.

Change of Measure between Light Travel Time and Euclidean Distances

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Heymann Y.

2013-04-01

Full Text Available The problem of cosmological distances is approached using a method based on the propagation of light in an expanding Universe. From the chan ge of measure between Light Travel Time and Euclidean Distances, a formula is deri ved to compute distances as a function of redshift. This formula is identical to Matti g’s formula (with q 0 = 1 / 2 which is based on Friedmann’s equations of general relativi ty.

Metrics for measuring distances in configuration spaces

International Nuclear Information System (INIS)

Sadeghi, Ali; Ghasemi, S. Alireza; Schaefer, Bastian; Mohr, Stephan; Goedecker, Stefan; Lill, Markus A.

2013-01-01

In order to characterize molecular structures we introduce configurational fingerprint vectors which are counterparts of quantities used experimentally to identify structures. The Euclidean distance between the configurational fingerprint vectors satisfies the properties of a metric and can therefore safely be used to measure dissimilarities between configurations in the high dimensional configuration space. In particular we show that these metrics are a perfect and computationally cheap replacement for the root-mean-square distance (RMSD) when one has to decide whether two noise contaminated configurations are identical or not. We introduce a Monte Carlo approach to obtain the global minimum of the RMSD between configurations, which is obtained from a global minimization over all translations, rotations, and permutations of atomic indices

Measuring short distance dispersal of Alliaria petiolata and determining potential long distance dispersal mechanisms

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Christopher A. Loebach

2018-03-01

Full Text Available Introduction Alliaria petiolata, an herbaceous plant, has invaded woodlands in North America. Its ecology has been thoroughly studied, but an overlooked aspect of its biology is seed dispersal distances and mechanisms. We measured seed dispersal distances in the field and tested if epizoochory is a potential mechanism for long-distance seed dispersal. Methods Dispersal distances were measured by placing seed traps in a sector design around three seed point sources, which consisted of 15 second-year plants transplanted within a 0.25 m radius circle. Traps were placed at intervals ranging from 0.25–3.25 m from the point source. Traps remained in the field until a majority of seeds were dispersed. Eight probability density functions were fitted to seed trap counts via maximum likelihood. Epizoochory was tested as a potential seed dispersal mechanism for A. petiolata through a combination of field and laboratory experiments. To test if small mammals transport A. petiolata seeds in their fur, experimental blocks were placed around dense A. petiolata patches. Each block contained a mammal inclusion treatment (MIT and control. The MIT consisted of a wood-frame (31 × 61× 31 cm covered in wire mesh, except for the two 31 × 31 cm ends, placed over a germination tray filled with potting soil. A pan filled with bait was placed in the center of the tray. The control frame (11 × 31 × 61 cm was placed over a germination tray and completely covered in wire mesh to exclude animal activity. Treatments were in the field for peak seed dispersal. In March, trays were moved to a greenhouse and A. petiolata seedlings were counted and then compared between treatments. To determine if A. petiolata seeds attach to raccoon (Procyon lotor and white-tailed deer (Odocoileus virginianus fur, wet and dry seeds were dropped onto wet and dry fur. Furs were rotated 180 degrees and the seeds that remained attached were counted. To measure seed retention, seeds

Underwater near-infrared spectroscopy can measure training adaptations in adolescent swimmers

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Ben Jones

2018-04-01

Full Text Available The development of an underwater near-infrared spectroscopy (uNIRS device has enabled previously unattainable measurements of peripheral muscle hemodynamics and oxygenation to be taken within the natural aquatic environment. The purposes of this study were (i to trial the use of uNIRS, in a real world training study, and (ii to monitor the effects of a swim training program upon muscle oxygenation status in short distance swimming. A total of 14 junior club level swimmers completed a repeated swim sprint test before and after an eight week endurance training program. A waterproof, portable Near-Infrared Spectroscopy device was attached to the vastus lateralis. uNIRS successfully measured changes in muscle oxygenation and blood volume in all individuals; rapid sub-second time resolution of the device was able to demonstrate muscle oxygenation changes during the characteristic swim movements. Post training heart rate recovery and swim performance time were significantly improved. uNIRS data also showed significant changes. A larger rise in deoxyhemoglobin during individual sprints suggested training induced an increase in muscle oxygen extraction; a faster recovery time for muscle oxygenation suggested positive training induced changes and significant changes in muscle blood flow also occur. As a strong correlation was seen between an increased reoxygenation rate and an improved swim performance time, these findings support the use of uNIRS as a new performance analysis tool in swimming.

A comparison between using distance sensors for measuring the pantograph vertically movement

Science.gov (United States)

Rob, R.; Panoiu, C.; Rusu-Anghel, S.; Panoiu, M.

2018-01-01

In railway transportation the most important problem to solve consists in assuring the safety traffic of people and freight. In this scope some of the geometrical parameters regarding the contact line must be measured. One of this parameter is the pantograph vertically movement, so it must use distance sensors. Present paper studies the performance of two kinds of distance sensors, an ultrasonic distance sensor and an infrared sensor. The performances are studied from the point of view of error distance measurement and the possibility of using a real time acquisition system. The researches were made on a laboratory model for the pantograph realized at the scale 1:2.

The Edit Distance as a Measure of Perceived Rhythmic Similarity

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Olaf Post

2012-07-01

Full Text Available The ‘edit distance’ (or ‘Levenshtein distance’ measure of distance between two data sets is defined as the minimum number of editing operations – insertions, deletions, and substitutions – that are required to transform one data set to the other (Orpen and Huron, 1992. This measure of distance has been applied frequently and successfully in music information retrieval, but rarely in predicting human perception of distance. In this study, we investigate the effectiveness of the edit distance as a predictor of perceived rhythmic dissimilarity under simple rhythmic alterations. Approaching rhythms as a set of pulses that are either onsets or silences, we study two types of alterations. The first experiment is designed to test the model’s accuracy for rhythms that are relatively similar; whether rhythmic variations with the same edit distance to a source rhythm are also perceived as relatively similar by human subjects. In addition, we observe whether the salience of an edit operation is affected by its metric placement in the rhythm. Instead of using a rhythm that regularly subdivides a 4/4 meter, our source rhythm is a syncopated 16-pulse rhythm, the son. Results show a high correlation between the predictions by the edit distance model and human similarity judgments (r = 0.87; a higher correlation than for the well-known generative theory of tonal music (r = 0.64. In the second experiment, we seek to assess the accuracy of the edit distance model in predicting relatively dissimilar rhythms. The stimuli used are random permutations of the son’s inter-onset intervals: 3-3-4-2-4. The results again indicate that the edit distance correlates well with the perceived rhythmic dissimilarity judgments of the subjects (r = 0.76. To gain insight in the relationships between the individual rhythms, the results are also presented by means of graphic phylogenetic trees.

Effect of race distance on muscle oxygenation in short-track speed skating.

Science.gov (United States)

Hesford, Catherine M; Laing, Stewart; Cardinale, Marco; Cooper, Chris E

2013-01-01

Previous work identified an asymmetry in tissue desaturation changes in the left and right quadriceps muscles during on-ice skating at maximal speed in males. The effect of changing race distance on the magnitude of desaturation or leg asymmetry is unknown. Six elite male skaters (age = 23 ± 1.8 yr, height = 1.8 ± 0.1 m, mass = 80.1 ± 5.7 kg, midthigh skinfold thickness = 7 ± 2 mm) and four elite female skaters (age = 21 ± 4 yr, height = 1.6 ± 0.1 m, mass = 65.2 ± 4.3 kg, midthigh skinfold thickness = 10 ± 1 mm) were studied. Subjects completed time trials over three race distances. Blood lactate concentration and O2 uptake measurements were combined with near-infrared spectroscopy measures of muscle oxygenation (TSI) and blood volume (tHb) in the right and left vastus lateralis. Neither race distance nor gender had a significant effect on the magnitude of maximal muscle desaturation (ΔTSI(max)). Pattern of local changes in tHb during individual laps was dependent upon subtle differences in skating technique used for the different race distances. Linear regression analysis revealed asymmetry between the right and left leg desaturation in males during the final stages of each race distance, but not in females. At all race distances, local muscle desaturation reached maximal values much more quickly than global VO(2peak). The use of wearable near-infrared spectroscopy devices enabled measurement of muscle oxygenation during competitive race simulation, thus providing unique insight into the effects of velocity and technique changes on local muscle oxygenation. This may have implications for training and race pacing in speed skating.

A Relative-Localization Algorithm Using Incomplete Pairwise Distance Measurements for Underwater Applications

Directory of Open Access Journals (Sweden)

Kae Y. Foo

2010-01-01

Full Text Available The task of localizing underwater assets involves the relative localization of each unit using only pairwise distance measurements, usually obtained from time-of-arrival or time-delay-of-arrival measurements. In the fluctuating underwater environment, a complete set of pair-wise distance measurements can often be difficult to acquire, thus hindering a straightforward closed-form solution in deriving the assets' relative coordinates. An iterative multidimensional scaling approach is presented based upon a weighted-majorization algorithm that tolerates missing or inaccurate distance measurements. Substantial modifications are proposed to optimize the algorithm, while the effects of refractive propagation paths are considered. A parametric study of the algorithm based upon simulation results is shown. An acoustic field-trial was then carried out, presenting field measurements to highlight the practical implementation of this algorithm.

Index of Refraction Measurements Using a Laser Distance Meter

Science.gov (United States)

Ochoa, Romulo; Fiorillo, Richard; Ochoa, Cris

2014-01-01

We present a simple method to determine the refractive indices of transparent media using a laser distance meter. Indices of refraction have been obtained by measuring the speed of light in materials. Some speed of light techniques use time-of-flight measurements in which pulses are emitted by lasers and the time interval is measured for the pulse…

A Simple Device for Lens-to-Sample Distance Adjustment in Laser-Induced Breakdown Spectroscopy (LIBS).

Science.gov (United States)

Cortez, Juliana; Farias Filho, Benedito B; Fontes, Laiane M; Pasquini, Celio; Raimundo, Ivo M; Pimentel, Maria Fernanda; de Souza Lins Borba, Flávia

2017-04-01

A simple device based on two commercial laser pointers is described to assist in the analysis of samples that present uneven surfaces and/or irregular shapes using laser-induced breakdown spectroscopy (LIBS). The device allows for easy positioning of the sample surface at a reproducible distance from the focusing lens that conveys the laser pulse to generate the micro-plasma in a LIBS system, with reproducibility better than ±0.2 mm. In this way, fluctuations in the fluence (J cm -2 ) are minimized and the LIBS analytical signals can be obtained with a better precision even when samples with irregular surfaces are probed.

Anatomy-Based navigation for ventriculostomy: Nasion-coronal suture distance measurement

Directory of Open Access Journals (Sweden)

Mevci Özdemir

2014-09-01

Full Text Available Objective: In this study we aimed to determine a landmark that can be measured through the skin with nasal mid-point (bregma to coronal suture, and additionally an average value was calculated. We report, to our knowledge, the distance between the nasion-coronal sutures is reported for the first time in Turkish population. Methods: The study included 30 craniums and 30 frontal bones. Each skull from midline nasal suture to coronal suture curved up at the distance was measured with tape measure. Results: Mean values were determined. Nasal suture between coronal suture distance average 12,2 cm (min10,3 cm, up to 13,5 cm were detected. Conclusion: Nasal suture is an easily palpable area through the skin. A small incision is carried down through skin to bone at the spot 12 cm back from the nasion 3 cm lateral to the midline for ventricular drainage operation. This data provide practical information for neurosurgeon and is available everywhere. J Clin Exp Invest 2014; 5 (3: 368-370

DISTANCES TO DARK CLOUDS: COMPARING EXTINCTION DISTANCES TO MASER PARALLAX DISTANCES

International Nuclear Information System (INIS)

Foster, Jonathan B.; Jackson, James M.; Stead, Joseph J.; Hoare, Melvin G.; Benjamin, Robert A.

2012-01-01

We test two different methods of using near-infrared extinction to estimate distances to dark clouds in the first quadrant of the Galaxy using large near-infrared (Two Micron All Sky Survey and UKIRT Infrared Deep Sky Survey) surveys. Very long baseline interferometry parallax measurements of masers around massive young stars provide the most direct and bias-free measurement of the distance to these dark clouds. We compare the extinction distance estimates to these maser parallax distances. We also compare these distances to kinematic distances, including recent re-calibrations of the Galactic rotation curve. The extinction distance methods agree with the maser parallax distances (within the errors) between 66% and 100% of the time (depending on method and input survey) and between 85% and 100% of the time outside of the crowded Galactic center. Although the sample size is small, extinction distance methods reproduce maser parallax distances better than kinematic distances; furthermore, extinction distance methods do not suffer from the kinematic distance ambiguity. This validation gives us confidence that these extinction methods may be extended to additional dark clouds where maser parallaxes are not available.

Structures of peptide families by nuclear magnetic resonance spectroscopy and distance geometry

Energy Technology Data Exchange (ETDEWEB)

Pease, J.H.

1989-12-01

The three dimensional structures of several small peptides were determined using a combination of {sup 1}H nuclear magnetic resonance (NMR) and distance geometry calculations. These techniques were found to be particularly helpful for analyzing structural differences between related peptides since all of the peptides' {sup 1}H NMR spectra are very similar. The structures of peptides from two separate classes are presented. Peptides in the first class are related to apamin, an 18 amino acid peptide toxin from honey bee venom. The {sup 1}H NMR assignments and secondary structure determination of apamin were done previously. Quantitative NMR measurements and distance geometry calculations were done to calculate apamin's three dimensional structure. Peptides in the second class are 48 amino acid toxins from the sea anemone Radianthus paumotensis. The {sup 1}H NMR assignments of toxin II were done previously. The {sup 1}H NMR assignments of toxin III and the distance geometry calculations for both peptides are presented.

Comparison of efficiency of distance measurement methodologies in mango (Mangifera indica) progenies based on physicochemical descriptors.

Science.gov (United States)

Alves, E O S; Cerqueira-Silva, C B M; Souza, A M; Santos, C A F; Lima Neto, F P; Corrêa, R X

2012-03-14

We investigated seven distance measures in a set of observations of physicochemical variables of mango (Mangifera indica) submitted to multivariate analyses (distance, projection and grouping). To estimate the distance measurements, five mango progeny (total of 25 genotypes) were analyzed, using six fruit physicochemical descriptors (fruit weight, equatorial diameter, longitudinal diameter, total soluble solids in °Brix, total titratable acidity, and pH). The distance measurements were compared by the Spearman correlation test, projection in two-dimensional space and grouping efficiency. The Spearman correlation coefficients between the seven distance measurements were, except for the Mahalanobis' generalized distance (0.41 ≤ rs ≤ 0.63), high and significant (rs ≥ 0.91; P < 0.001). Regardless of the origin of the distance matrix, the unweighted pair group method with arithmetic mean grouping method proved to be the most adequate. The various distance measurements and grouping methods gave different values for distortion (-116.5 ≤ D ≤ 74.5), cophenetic correlation (0.26 ≤ rc ≤ 0.76) and stress (-1.9 ≤ S ≤ 58.9). Choice of distance measurement and analysis methods influence the.

Radioactivity measurements by liquid scintillation spectroscopy

International Nuclear Information System (INIS)

Cassette, Ph.

2004-01-01

The activity measurement techniques by liquid scintillation spectroscopy consist to mix the radioactive solution to measure with a scintillating liquid and to transform the ionizing radiations, resulting from decays, into light, detectable and quantifiable. The main advantages of these techniques are the easiness of preparation of the radioactive sources, the geometric efficiency of detection of 4π and the possibility of detection of low-level energy radiations. There are one of the only methods giving the possibility to measure the activity of pure β radionuclides; indeed, the nuclear disintegration is not accompanied of gamma radiations detectable by other techniques. There are one of the only methods too of measurement of radionuclides which disintegrate by electron capture and especially those leading to the emission of low-level energy ionizing radiations. Liquid scintillation spectroscopy can be used as an absolute method of activity measurement that is to say without the use of a calibration standard. The modern liquid scintillation counting devices can be very sensitive; the measurement of micro-activities being possible. Some of the applications of these activity measurement techniques are the carbon 14 dating and the geological tracing. Their main disadvantage is the global energetic yield which is low and variable in terms of the composition of the scintillation source necessitating to calculate the detection yield for each condition of measurement. (O.M.)

A Test of the Validity of Projective and Quasi-Projective Measures of Interpersonal Distance.

Science.gov (United States)

Jones, Stanley E.; Aiello, John R.

1979-01-01

Discusses research supporting the conclusion that projective and quasi-projective measures of interpersonal distance do not measure the same phenomena as interactional measures. It is possible that they are more indicative of psychological rather than physical distance. (JMF)

An International Parallax Campaign to Measure Distance to the Moon and Mars

Science.gov (United States)

Cenadelli, D.; Zeni, M.; Bernagozzi, A.; Calcidese, P.; Ferreira, L.; Hoang, C.; Rijsdijk, C.

2009-01-01

Trigonometric parallax is a powerful method to work out the distance of celestial bodies, and it was used in the past to measure the distance of the Moon, Venus, Mars and nearby stars. We set up an observation campaign for high school and undergraduate students with the purpose to measure both the Moon's and Mars' parallax. To have a large enough…

Real-Time and Meter-Scale Absolute Distance Measurement by Frequency-Comb-Referenced Multi-Wavelength Interferometry.

Science.gov (United States)

Wang, Guochao; Tan, Lilong; Yan, Shuhua

2018-02-07

We report on a frequency-comb-referenced absolute interferometer which instantly measures long distance by integrating multi-wavelength interferometry with direct synthetic wavelength interferometry. The reported interferometer utilizes four different wavelengths, simultaneously calibrated to the frequency comb of a femtosecond laser, to implement subwavelength distance measurement, while direct synthetic wavelength interferometry is elaborately introduced by launching a fifth wavelength to extend a non-ambiguous range for meter-scale measurement. A linearity test performed comparatively with a He-Ne laser interferometer shows a residual error of less than 70.8 nm in peak-to-valley over a 3 m distance, and a 10 h distance comparison is demonstrated to gain fractional deviations of ~3 × 10 -8 versus 3 m distance. Test results reveal that the presented absolute interferometer enables precise, stable, and long-term distance measurements and facilitates absolute positioning applications such as large-scale manufacturing and space missions.

THE DISTANCE MEASUREMENT OF NGC 1313 WITH CEPHEIDS

International Nuclear Information System (INIS)

Qing, Gao; Wang, Wei; Liu, Ji-Feng; Yoachim, Peter

2015-01-01

We present the detection of Cepheids in the barred spiral galaxy NGC 1313, using the Wide Field and Planetary Camera 2 on the Hubble Space Telescope. Twenty B(F450W) and V(F555W) epochs of observations spanning over three weeks were obtained, on which the profile-fitting photometry of all stars in the monitored field was performed using the package HSTphot. A sample of 26 variable stars have been identified to be Cepheids, with periods between 3 and 14 days. Based on the derived period-luminosity relations in B- and V-bands, we obtain an extinction-corrected distance modulus of μ NGC 1313 = 28.32 ± 0.08 (random) ± 0.06 (systematic), employing the Large Magellanic Cloud as the distance zero point calibrator. The above moduli correspond to a distance of 4.61 ± 0.17 (random) ±0.13 (systematic) Mpc, consistent with previous measurements reported in the literature within uncertainties. In addition, the reddening to NGC 1313 is found to be small

In situ measurements of fuel retention by laser induced desorption spectroscopy in TEXTOR

Science.gov (United States)

Zlobinski, M.; Philipps, V.; Schweer, B.; Huber, A.; Stoschus, H.; Brezinsek, S.; Samm, U.; TEXTOR Team

2011-12-01

In future fusion devices such as ITER tritium retention due to tritium co-deposition in mixed material layers can be a serious safety problem. Laser induced desorption spectroscopy (LIDS) can measure the hydrogen content of hydrogenic carbon layers locally on plasma-facing components, while hydrogen is used as a tritium substitute. For several years, this method has been applied in the TEXTOR tokamak in situ during plasma operation to monitor the hydrogen content in space and time. This work shows the LIDS signal reproducibility and studies the effects of different plasma conditions, desorption distances from the plasma and different laser energies using a dedicated sample with constant hydrogen amount. Also the LIDS signal evaluation procedure is described in detail and the detection limits for different conditions in the TEXTOR tokamak are estimated.

Experience of precision measuring distances by invar wires at accelerators

International Nuclear Information System (INIS)

Porubaj, N.I.

1977-01-01

With a view to determining the deformations and displacements of the ring foundation of the ITEP accelerator, the method of very accurate distance measurements by means of invar wires and strips is described. Measurement errors are analyzed. This method has allowed to measure distances up to 40 m with a mean-square error of less than 40 μm. The calibration accuracy of 3 and 25-m measuring wires has been determined to be +- 27 μm. Time instability of the wires is +- 16 μm. It is shown that strips are more stable in time than wires. Elongation of 6, 19, 25 and 38 m invar wires has been measured as function of the tension time. The error due to tension of a 38-m wire may be tangible. Data on thermal coefficient variation in time has been obtained for invar wires and strips. The multiannual measurements of the ring foundation deformations show that variations of the mean radius are caused by increases of concrete temperature. Temperature increase by only 1 deg caused mean radius increase of 0.3 mm

Real-Time and Meter-Scale Absolute Distance Measurement by Frequency-Comb-Referenced Multi-Wavelength Interferometry

Directory of Open Access Journals (Sweden)

Guochao Wang

2018-02-01

Full Text Available We report on a frequency-comb-referenced absolute interferometer which instantly measures long distance by integrating multi-wavelength interferometry with direct synthetic wavelength interferometry. The reported interferometer utilizes four different wavelengths, simultaneously calibrated to the frequency comb of a femtosecond laser, to implement subwavelength distance measurement, while direct synthetic wavelength interferometry is elaborately introduced by launching a fifth wavelength to extend a non-ambiguous range for meter-scale measurement. A linearity test performed comparatively with a He–Ne laser interferometer shows a residual error of less than 70.8 nm in peak-to-valley over a 3 m distance, and a 10 h distance comparison is demonstrated to gain fractional deviations of ~3 × 10−8 versus 3 m distance. Test results reveal that the presented absolute interferometer enables precise, stable, and long-term distance measurements and facilitates absolute positioning applications such as large-scale manufacturing and space missions.

Geometric measures of quantum correlations: characterization, quantification, and comparison by distances and operations

International Nuclear Information System (INIS)

Roga, W; Illuminati, F; Spehner, D

2016-01-01

We investigate and compare three distinguished geometric measures of bipartite quantum correlations that have been recently introduced in the literature: the geometric discord, the measurement-induced geometric discord, and the discord of response, each one defined according to three contractive distances on the set of quantum states, namely the trace, Bures, and Hellinger distances. We establish a set of exact algebraic relations and inequalities between the different measures. In particular, we show that the geometric discord and the discord of response based on the Hellinger distance are easy to compute analytically for all quantum states whenever the reference subsystem is a qubit. These two measures thus provide the first instance of discords that are simultaneously fully computable, reliable (since they satisfy all the basic Axioms that must be obeyed by a proper measure of quantum correlations), and operationally viable (in terms of state distinguishability). We apply the general mathematical structure to determine the closest classical-quantum state of a given state and the maximally quantum-correlated states at fixed global state purity according to the different distances, as well as a necessary condition for a channel to be quantumness breaking. (paper)

Distance measurements from supernovae and dark energy constraints

International Nuclear Information System (INIS)

Wang Yun

2009-01-01

Constraints on dark energy from current observational data are sensitive to how distances are measured from Type Ia supernova (SN Ia) data. We find that flux averaging of SNe Ia can be used to test the presence of unknown systematic uncertainties, and yield more robust distance measurements from SNe Ia. We have applied this approach to the nearby+SDSS+ESSENCE+SNLS+HST set of 288 SNe Ia, and the 'Constitution' set of 397 SNe Ia. Combining the SN Ia data with cosmic microwave background anisotropy data from Wilkinson Microwave Anisotropy Probe 5 yr observations, the Sloan Digital Sky Survey baryon acoustic oscillation measurements, the data of 69 gamma-ray bursts (GRBs) , and the Hubble constant measurement from the Hubble Space Telescope project SHOES, we measure the dark energy density function X(z)≡ρ X (z)/ρ X (0) as a free function of redshift (assumed to be a constant at z>1 or z>1.5). Without the flux averaging of SNe Ia, the combined data using the Constitution set of SNe Ia seem to indicate a deviation from a cosmological constant at ∼95% confidence level at 0 98% confidence level for z≤0.75 using the combined data with 288 SNe Ia from nearby+SDSS+ESSENCE+SNLS+HST, independent of the assumptions about X(z≥1). We quantify dark energy constraints without assuming a flat Universe using the dark energy figure of merit for both X(z) and a dark energy equation-of-state linear in the cosmic scale factor.

Bullet Ultrasonic Obstruction Detection & Distance Measurement Using AVR Microcontroller

Directory of Open Access Journals (Sweden)

Satish Pandey

2008-08-01

Full Text Available This paper describes the practical implementation of a short range ultrasonic obstruction detection and distance measurement device. By employing an ultrasonic transducer pair for producing ultrasonic sounds and sensing the reflected sound waves, the obstructions are detected. The hardware interface uses an Atmel ATmega8 AVR microcontroller to facilitate the generation of 40 kHz signal burst which is used in the transmitter circuit, and also to process the received signal for measuring the time of flight of reflected waves and exact distance of the obstruction. The program for this device is developed in WinAVR, and the code generated is dumped into microcontroller using AVR Studio. Educational aspects of this project include the mastery of a programming language and corresponding tools, the design of a functional and intuitive embedded application, and the development of appropriate hardware to build the device.

Measuring the Accuracy of Simple Evolving Connectionist System with Varying Distance Formulas

Science.gov (United States)

Al-Khowarizmi; Sitompul, O. S.; Suherman; Nababan, E. B.

2017-12-01

Simple Evolving Connectionist System (SECoS) is a minimal implementation of Evolving Connectionist Systems (ECoS) in artificial neural networks. The three-layer network architecture of the SECoS could be built based on the given input. In this study, the activation value for the SECoS learning process, which is commonly calculated using normalized Hamming distance, is also calculated using normalized Manhattan distance and normalized Euclidean distance in order to compare the smallest error value and best learning rate obtained. The accuracy of measurement resulted by the three distance formulas are calculated using mean absolute percentage error. In the training phase with several parameters, such as sensitivity threshold, error threshold, first learning rate, and second learning rate, it was found that normalized Euclidean distance is more accurate than both normalized Hamming distance and normalized Manhattan distance. In the case of beta fibrinogen gene -455 G/A polymorphism patients used as training data, the highest mean absolute percentage error value is obtained with normalized Manhattan distance compared to normalized Euclidean distance and normalized Hamming distance. However, the differences are very small that it can be concluded that the three distance formulas used in SECoS do not have a significant effect on the accuracy of the training results.

Measuring the Distance of Moving Objects from Big Trajectory Data

Directory of Open Access Journals (Sweden)

Khaing Phyo Wai

2017-03-01

Full Text Available Location-based services have become important in social networking, mobile applications, advertising, traffic monitoring, and many other domains. The growth of location sensing devices has led to the vast generation of dynamic spatial-temporal data in the form of moving object trajectories which can be characterized as big trajectory data. Big trajectory data enables the opportunities such as analyzing the groups of moving objects. To obtain such facilities, the issue of this work is to find a distance measurement method that respects the geographic distance and the semantic similarity for each trajectory. Measurement of similarity between moving objects is a difficult task because not only their position changes but also their semantic features vary. In this research, a method to measure trajectory similarity based on both geographical features and semantic features of motion is proposed. Finally, the proposed methods are practically evaluated by using real trajectory dataset.

Plasma-cavity ringdown spectroscopy for analytical measurement: Progress and prospectives

Energy Technology Data Exchange (ETDEWEB)

Zhang, Sida; Liu, Wei [Research Center of Analytical Instrumentation, Analytical and Testing Center, College of Chemistry, Sichuan University, Chengdu (China); Zhang, Xiaohe [College of Water Resources and Hydropower, Sichuan University, Chengdu (China); Duan, Yixiang, E-mail: yduan@scu.edu.cn [Research Center of Analytical Instrumentation, Analytical and Testing Center, College of Chemistry, Sichuan University, Chengdu (China)

2013-07-01

Plasma-cavity ringdown spectroscopy is a powerful absorption technique for analytical measurement. It combines the inherent advantages of high sensitivity, absolute measurement, and relative insensitivity to light source intensity fluctuations of the cavity ringdown technique with use of plasma as an atomization/ionization source. In this review, we briefly describe the background and principles of plasma-cavity ringdown spectroscopy(CRDS) technology, the instrumental components, and various applications. The significant developments of the plasma sources, lasers, and cavity optics are illustrated. Analytical applications of plasma-CRDS for elemental detection and isotopic measurement in atomic spectrometry are outlined in this review. Plasma-CRDS is shown to have a promising future for various analytical applications, while some further efforts are still needed in fields such as cavity design, plasma source design, instrumental improvement and integration, as well as potential applications in radical and molecular measurements. - Highlights: • Plasma-based cavity ringdown spectroscopy • High sensitivity and high resolution • Elemental and isotopic measurements.

Atomic force microscope-assisted scanning tunneling spectroscopy under ambient conditions.

Science.gov (United States)

Vakhshouri, Amin; Hashimoto, Katsushi; Hirayama, Yoshiro

2014-12-01

We have developed a method of atomic force microscopy (AFM)-assisted scanning tunneling spectroscopy (STS) under ambient conditions. An AFM function is used for rapid access to a selected position prior to performing STS. The AFM feedback is further used to suppress vertical thermal drift of the tip-sample distance during spectroscopy, enabling flexible and stable spectroscopy measurements at room temperature. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Absolute distance measurement with correction of air refractive index by using two-color dispersive interferometry.

Science.gov (United States)

Wu, Hanzhong; Zhang, Fumin; Liu, Tingyang; Li, Jianshuang; Qu, Xinghua

2016-10-17

Two-color interferometry is powerful for the correction of the air refractive index especially in the turbulent air over long distance, since the empirical equations could introduce considerable measurement uncertainty if the environmental parameters cannot be measured with sufficient precision. In this paper, we demonstrate a method for absolute distance measurement with high-accuracy correction of air refractive index using two-color dispersive interferometry. The distances corresponding to the two wavelengths can be measured via the spectrograms captured by a CCD camera pair in real time. In the long-term experiment of the correction of air refractive index, the experimental results show a standard deviation of 3.3 × 10-8 for 12-h continuous measurement without the precise knowledge of the environmental conditions, while the variation of the air refractive index is about 2 × 10-6. In the case of absolute distance measurement, the comparison with the fringe counting interferometer shows an agreement within 2.5 μm in 12 m range.

Reliability of linear distance measurement for dental implant length with standardized periapical radiographs

International Nuclear Information System (INIS)

Wakoh, Mamoru; Harada, Takuya; Otonari, Takamichi

2006-01-01

The purpose of this study was to investigate the accuracy of distance measurements of implant length based on periapical radiographs compared with that of other modalities. We carried out an experimental trial to compare precision in distance measurement. Dental implant fixtures were buried in the canine and first molar regions. These were then subjected to periapical (PE) radiography, panoramic (PA) radiography conventional (CV) and medical computed (CT) tomography. The length of the implant fixture on each film was measured by nine observers and degree of precision was statistically analyzed. The precision of both PE radiographs and CT tomograms was closest at the highest level. Standardized PE radiography, in particular, was superior to CT tomography in the first molar region. This suggests that standardized PE radiographs should be utilized as a reliable modality for longitudinal and linear distance measurement, depending on implant length at local implantation site. (author)

Laser-Induced Breakdown Spectroscopy for Mars surface analysis: capabilities at stand-off distances and detection of chlorine and sulfur elements

International Nuclear Information System (INIS)

Salle, Beatrice; Lacour, Jean-Luc; Vors, Evelyne; Fichet, Pascal; Maurice, Sylvestre; Cremers, David A.; Wiens, Roger C.

2004-01-01

An international consortium is studying the feasibility of performing in situ geochemical analysis of Mars soils and rocks at stand-off distances up to several meters using the Laser-Induced Breakdown Spectroscopy (LIBS) technique. Stand-off analysis for Martian exploration imposes particular requirements on instrumentation, and it is necessary to first test the performance of such a system in the laboratory. In this paper, we test the capabilities of two different experimental setups. The first one is dedicated to the qualitative analysis of metals and rocks at distances between 3 and 12 m. With the second one, we have obtained quantitative results for aluminum alloys and developed a spectral database under Martian conditions for sulfur and chlorine, two elements that are geologically interesting but generally difficult to detect by LIBS under standard conditions (atmospheric pressure, close distance). These studies were carried out to determine an optimal instrumental design for in situ Mars analysis. The quality of analytical results affected by the optical elements and spectrometer has been particularly highlighted

New Trends Of Measurement And Assessment In Distance Education

Directory of Open Access Journals (Sweden)

Zeki KAYA

2014-01-01

Full Text Available Distance education is a discipline that offers solutions to some important education problems. Distance education, contribute to the solution to the problems such as; inequality of opportunities, lifelong education, the implementation of a series of individual and social goals that can contribute to and benefit from educational technology and self-learning. In distance education, methods of measurement and assessment must be consistent with the objectives and contents of teaching. A major interest of formative assessment is determining the students’ learning level of each behavior in the interested unit. In summative assessment, performances of students on some units are measured broader than formative assessment. A computerized adaptive testing, CAT, is the test managed by computer in which each item is introduced and the decision to stop are dynamically imposed based on the students answers and his/her estimated knowledge level. In CAT applications, students do not take the same test. Despite item numbers and properties of items are different for the students; the precise of measures improves in positioning students on an ability or success continuum in CAT applications. In CAT applications, questions answered by a student depend on the student's ability or learning level. In item response theory, there are some models to estimate a student’s ability level, such as three-parameter logistic model. Cheating in exams or other academic assignments can be defined as use resources not allowed to use or having someone else to take exams or assignments. Some precautions must be taken about cheating such as a live proctoring, using web cams, and using a plagiarism detection program.

Measurement of a Cosmographic Distance Ratio with Galaxy and Cosmic Microwave Background Lensing.

Science.gov (United States)

Miyatake, Hironao; Madhavacheril, Mathew S; Sehgal, Neelima; Slosar, Anže; Spergel, David N; Sherwin, Blake; van Engelen, Alexander

2017-04-21

We measure the gravitational lensing shear signal around dark matter halos hosting constant mass galaxies using light sources at z∼1 (background galaxies) and at the surface of last scattering at z∼1100 (the cosmic microwave background). The galaxy shear measurement uses data from the CFHTLenS survey, and the microwave background shear measurement uses data from the Planck satellite. The ratio of shears from these cross-correlations provides a purely geometric distance measurement across the longest possible cosmological lever arm. This is because the matter distribution around the halos, including uncertainties in galaxy bias and systematic errors such as miscentering, cancels in the ratio for halos in thin redshift slices. We measure this distance ratio in three different redshift slices of the constant mass (CMASS) sample and combine them to obtain a 17% measurement of the distance ratio, r=0.390_{-0.062}^{+0.070}, at an effective redshift of z=0.53. This is consistent with the predicted ratio from the Planck best-fit cold dark matter model with a cosmological constant cosmology of r=0.419.

Clustering by Partitioning around Medoids using Distance-Based Similarity Measures on Interval-Scaled Variables

Directory of Open Access Journals (Sweden)

D. L. Nkweteyim

2018-03-01

Full Text Available It is reported in this paper, the results of a study of the partitioning around medoids (PAM clustering algorithm applied to four datasets, both standardized and not, and of varying sizes and numbers of clusters. The angular distance proximity measure in addition to the two more traditional proximity measures, namely the Euclidean distance and Manhattan distance, was used to compute object-object similarity. The data used in the study comprise three widely available datasets, and one that was constructed from publicly available climate data. Results replicate some of the well known facts about the PAM algorithm, namely that the quality of the clusters generated tend to be much better for small datasets, that the silhouette value is a good, even if not perfect, guide for the optimal number of clusters to generate, and that human intervention is required to interpret generated clusters. Additionally, results also indicate that the angular distance measure, which traditionally has not been widely used in clustering, outperforms both the Euclidean and Manhattan distance metrics in certain situations.

Superheterodyne configuration for two-wavelength interferometry applied to absolute distance measurement

International Nuclear Information System (INIS)

Le Floch, Sebastien; Salvade, Yves; Droz, Nathalie; Mitouassiwou, Rostand; Favre, Patrick

2010-01-01

We present a new superheterodyne technique for long-distance measurements by two-wavelength interferometry (TWI). While conventional systems use two acousto-optic modulators to generate two different heterodyne frequencies, here the two frequencies result from synchronized sweeps of optical and radio frequencies. A distributed feedback laser source is injected in an intensity modulator that is driven at the half-wave voltage mode. A radio-frequency signal is applied to this intensity modulator to generate two optical sidebands around the optical carrier. This applied radio frequency consists of a digital ramp between 13 and 15 GHz, with 1 ms duration and with an accuracy of better than 1 ppm. Simultaneously, the laser source is frequency modulated by a current modulation that is synchronized on the radio-frequency ramp as well as on a triangle waveform. These two frequency-swept optical signals at the output of the modulator illuminate a Michelson interferometer and create two distinct distance-dependent heterodyne frequencies on the photodetector. The superheterodyne signal is then detected and bandpass filtered to retrieve the absolute distance measurement. Experiments between 1 and 15 m confirm the validity of this new concept, leading to a distance accuracy of ± 50 μm for a 1 ms acquisition time.

Precision lifetime measurements using the recoil distance method

International Nuclear Information System (INIS)

Kruecken, R.

2000-01-01

The recoil distance method (RDM) for the measurements of lifetimes of excited nuclear levels in the range from about 1 ps to 1,000 ps is reviewed. The New Yale Plunger Device for RDM experiments is introduced and the Differential Decay Curve Method for their analysis is reviewed. Results from recent RDM experiments on SD bands in the mass-190 region, shears bands in the neutron deficient lead isotopes, and ground state bands in the mass-130 region are presented. Perspectives for the use of RDM measurements in the study of neutron-rich nuclei are discussed

Precision Lifetime Measurements Using the Recoil Distance Method

Science.gov (United States)

Krücken, R.

2000-01-01

The recoil distance method (RDM) for the measurements of lifetimes of excited nuclear levels in the range from about 1 ps to 1000 ps is reviewed. The New Yale Plunger Device for RDM experiments is introduced and the Differential Decay Curve Method for their analysis is reviewed. Results from recent RDM experiments on SD bands in the mass-190 region, shears bands in the neutron deficient lead isotopes, and ground state bands in the mass-130 region are presented. Perspectives for the use of RDM measurements in the study of neutron-rich nuclei are discussed. PMID:27551587

Air temperature measurements based on the speed of sound to compensate long distance interferometric measurements

Directory of Open Access Journals (Sweden)

Astrua Milena

2014-01-01

Full Text Available A method to measure the real time temperature distribution along an interferometer path based on the propagation of acoustic waves is presented. It exploits the high sensitivity of the speed of sound in air to the air temperature. In particular, it takes advantage of a special set-up where the generation of the acoustic waves is synchronous with the amplitude modulation of a laser source. A photodetector converts the laser light to an electronic signal considered as reference, while the incoming acoustic waves are focused on a microphone and generate a second signal. In this condition, the phase difference between the two signals substantially depends on the temperature of the air volume interposed between the sources and the receivers. The comparison with the traditional temperature sensors highlighted the limit of the latter in case of fast temperature variations and the advantage of a measurement integrated along the optical path instead of a sampling measurement. The capability of the acoustic method to compensate the interferometric distance measurements due to air temperature variations has been demonstrated for distances up to 27 m.

The EnMAP Spaceborne Imaging Spectroscopy Mission for Earth Observation

Directory of Open Access Journals (Sweden)

Luis Guanter

2015-07-01

Full Text Available Imaging spectroscopy, also known as hyperspectral remote sensing, is based on the characterization of Earth surface materials and processes through spectrally-resolved measurements of the light interacting with matter. The potential of imaging spectroscopy for Earth remote sensing has been demonstrated since the 1980s. However, most of the developments and applications in imaging spectroscopy have largely relied on airborne spectrometers, as the amount and quality of space-based imaging spectroscopy data remain relatively low to date. The upcoming Environmental Mapping and Analysis Program (EnMAP German imaging spectroscopy mission is intended to fill this gap. An overview of the main characteristics and current status of the mission is provided in this contribution. The core payload of EnMAP consists of a dual-spectrometer instrument measuring in the optical spectral range between 420 and 2450 nm with a spectral sampling distance varying between 5 and 12 nm and a reference signal-to-noise ratio of 400:1 in the visible and near-infrared and 180:1 in the shortwave-infrared parts of the spectrum. EnMAP images will cover a 30 km-wide area in the across-track direction with a ground sampling distance of 30 m. An across-track tilted observation capability will enable a target revisit time of up to four days at the Equator and better at high latitudes. EnMAP will contribute to the development and exploitation of spaceborne imaging spectroscopy applications by making high-quality data freely available to scientific users worldwide.

The ROSPHERE γ-ray spectroscopy array

Energy Technology Data Exchange (ETDEWEB)

Bucurescu, D.; Căta-Danil, I.; Ciocan, G.; Costache, C.; Deleanu, D.; Dima, R. [Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN-HH, R-077125 Bucharest (Romania); Filipescu, D. [Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN-HH, R-077125 Bucharest (Romania); Extreme Light Infrastructure Nuclear Physics - ELI-NP, Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN-HH, R-077125 Bucharest (Romania); Florea, N.; Ghiţă, D.G.; Glodariu, T.; Ivaşcu, M.; Lică, R.; Mărginean, N.; Mărginean, R. [Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN-HH, R-077125 Bucharest (Romania); Mihai, C., E-mail: cmihai@tandem.nipne.ro [Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN-HH, R-077125 Bucharest (Romania); Negret, A.; Niţă, C.R.; Olăcel, A.; Pascu, S.; Sava, T. [Horia Hulubei National Institute of Physics and Nuclear Engineering - IFIN-HH, R-077125 Bucharest (Romania); and others

2016-11-21

The ROmanian array for SPectroscopy in HEavy ion REactions (ROSPHERE) has been designed as a multi-detector setup dedicated to γ-ray spectroscopy studies at the Bucharest 9 MV Tandem accelerator. Consisting of up to 25 detectors (either Compton suppressed HPGe detectors or fast LaBr{sub 3}(Ce) scintillator detectors) together with a state of the art plunger device, ROSPHERE is a powerful tool for lifetime measurements using the Recoil Distance Doppler Shift (RDDS) and the in-beam Fast Electronic Scintillation Timing (FEST) methods. The array's geometry, detectors, electronics and data acquisition system are described. Selected results from the first experimental campaigns are also presented.

Evaluation of laser-induced breakdown spectroscopy analysis potential for addressing radiological threats from a distance

International Nuclear Information System (INIS)

Gaona, I.; Serrano, J.; Moros, J.; Laserna, J.J.

2014-01-01

Although radioactive materials are nowadays valuable tools in nearly all fields of modern science and technology, the dangers stemming from the uncontrolled use of ionizing radiation are more than evident. Since preparedness is a key issue to face the risks of a radiation dispersal event, development of rapid and efficient monitoring technologies to control the contamination caused by radioactive materials is of crucial interest. Laser-induced breakdown spectroscopy (LIBS) exhibits appealing features for this application. This research focuses on the assessment of LIBS potential for the in-situ fingerprinting and identification of radioactive material surrogates from a safe distance. LIBS selectivity and sensitivity to detect a variety of radioactive surrogates, namely 59 Co, 88 Sr, 130 Ba, 133 Cs, 193 Ir and 238 U, on the surface of common urban materials at a distance of 30 m have been evaluated. The performance of the technique for nuclear forensics has been also studied on different model scenarios. Findings have revealed the difficulties to detect and to identify the analytes depending on the surface being interrogated. However, as demonstrated, LIBS shows potential enough for prompt and accurate gathering of essential evidence at a number of sites after the release, either accidental or intentional, of radioactive material. The capability of standoff analysis confers to LIBS unique advantages in terms of fast and safe inspection of forensic scenarios. The identity of the radioactive surrogates is easily assigned from a distance and the sensitivity to their detection is in the range of a few hundreds of ng per square centimeter. - Highlights: • Distant identification of radioactive surrogates on urban surfaces has been proved. • LIBS sensitivity to distant detection of radioactive surrogates has been checked. • Influences of the atmosphere on emission signals have been ascertained. • Usage of standoff LIBS for identifying forensic evidences has been

Evaluation of laser-induced breakdown spectroscopy analysis potential for addressing radiological threats from a distance

Energy Technology Data Exchange (ETDEWEB)

Gaona, I.; Serrano, J.; Moros, J.; Laserna, J.J., E-mail: laserna@uma.es

2014-06-01

Although radioactive materials are nowadays valuable tools in nearly all fields of modern science and technology, the dangers stemming from the uncontrolled use of ionizing radiation are more than evident. Since preparedness is a key issue to face the risks of a radiation dispersal event, development of rapid and efficient monitoring technologies to control the contamination caused by radioactive materials is of crucial interest. Laser-induced breakdown spectroscopy (LIBS) exhibits appealing features for this application. This research focuses on the assessment of LIBS potential for the in-situ fingerprinting and identification of radioactive material surrogates from a safe distance. LIBS selectivity and sensitivity to detect a variety of radioactive surrogates, namely {sup 59}Co, {sup 88}Sr, {sup 130}Ba, {sup 133}Cs, {sup 193}Ir and {sup 238}U, on the surface of common urban materials at a distance of 30 m have been evaluated. The performance of the technique for nuclear forensics has been also studied on different model scenarios. Findings have revealed the difficulties to detect and to identify the analytes depending on the surface being interrogated. However, as demonstrated, LIBS shows potential enough for prompt and accurate gathering of essential evidence at a number of sites after the release, either accidental or intentional, of radioactive material. The capability of standoff analysis confers to LIBS unique advantages in terms of fast and safe inspection of forensic scenarios. The identity of the radioactive surrogates is easily assigned from a distance and the sensitivity to their detection is in the range of a few hundreds of ng per square centimeter. - Highlights: • Distant identification of radioactive surrogates on urban surfaces has been proved. • LIBS sensitivity to distant detection of radioactive surrogates has been checked. • Influences of the atmosphere on emission signals have been ascertained. • Usage of standoff LIBS for identifying

Performance considerations of ultrasonic distance measurement with well defined properties

International Nuclear Information System (INIS)

Elmer, Hannes; Schweinzer, Herbert

2005-01-01

Conventional ultrasonic distance measurement systems based on narrow bandwidth ultrasonic bursts and amplitude detection are often used because of their low costs and easy implementation. However, the achievable results strongly depend on the actual environments where the system is implemented: in case of well defined objects that are always located near the measurement direction of the system, in general good results are obtained. If arbitrary objects are expected that are moreover located in arbitrary positions in front of the sensor, strongly object dependent areas where objects are detected with decreasing accuracy towards their borders must be taken into account. In previous works we developed an ultrasonic measurement system that provides accurate distance measurement values within a well defined detection area that is independent of the reflection properties of the objects. This measurement system is based on the One Bit Correlation method that is described in the following. To minimise its implementation efforts, it is necessary to examine the influence of the system parameters as e.g. the correlation length to the results that are expected in case of different signal to noise ratios of the received signal. In the following, these examinations are shown and the obtained results are discussed that allow getting a well conditioned system that makes best use of given system resources

Automation by microcomputer of a geodetic distance measuring instrument: The distinvar

International Nuclear Information System (INIS)

Bain, G.; Bore, C.; Coosemans, W.; Dupont, J.; Fabre, J.P.; Gavaggio, R.; Peron, F.

1985-01-01

The distinvar is an instrument for the precision measurement of distances up to 50 m. This report describes the latest developments at CERN which have improved its resolution to 2 μm and increased its speed of use. Measurements are automated by incorporating a microcomputer programmed in BASIC. (orig.)

Automation by microprocessor of an geodesic distance measuring instrument: The distinvar

International Nuclear Information System (INIS)

Bain, G.; Bore, C.; Coosemans, W.; Dupont, J.; Fabre, J.P.; Gavaggio, R.; Peron, F.

1984-01-01

The distinvar is an instrument for the precision measurement of distances up to 50 m. This report describes the latest developments at CERN which have improved its resolution to 2 micrometers and increased its speed of use. Measurements are automated by incorporating a microcomputer programmed in BASIC. (orig.)

Photoacoustic spectroscopy for analytical measurements

International Nuclear Information System (INIS)

Haisch, Christoph

2012-01-01

Many different techniques, such as UV/vis absorption, IR spectroscopy, fluorescence and Raman spectroscopy are routinely applied in chemical (micro-)analysis and chemical imaging, and a large variety of instruments is commercially available. Up to now, opto- or photoacoustic (PA) and other optothermal (OT) methods are less common and only a limited number of instruments reached a level of application beyond prototypes in research laboratories. The underlying principle of all these techniques is the detection of local heating due to the conversion of light into heat by optical absorption. Considering the versatility, robustness and instrumental simplicity of many PA techniques, it is surprising that the number of commercial instruments based on such approaches is so sparse. The impetus of this review is to summarize basic principles and possible applications described in the literature, in order to foster routine application of these techniques in industry, process analysis and environmental screening. While the terms OT and PA methods cover a very wide range of methods and physical phenomena, this review will concentrate on techniques with applications for analytical measurements. (topical review)

Spatiotemporal image correlation spectroscopy measurements of flow demonstrated in microfluidic channels

Science.gov (United States)

Rossow, Molly; Mantulin, William W.; Gratton, Enrico

2009-03-01

Accurate blood flow measurements during surgery can improve an operation's chance of success. We developed near-infrared spatio-temporal image spectroscopy (NIR-STICS), which has the potential to make blood flow measurements that are difficult to accomplish with existing methods. Specifically, we propose the technique and we show feasibility on phantom measurements. NIR-STICS has the potential of measuring the fluid velocity in small blood vessels (less than 1 mm in diameter) and of creating a map of blood flow rates over an area of approximately 1 cm2. NIR-STICS employs near-infrared spectroscopy to probe inside blood vessel walls and spatiotemporal image correlation spectroscopy to directly-without the use of a model-extract fluid velocity from the fluctuations within an image. We present computer simulations and experiments on a phantom system that demonstrate the effectiveness of NIR-STICS.

Study of Vis/NIR spectroscopy measurement on acidity of yogurt

Science.gov (United States)

He, Yong; Feng, Shuijuan; Wu, Di; Li, Xiaoli

2006-09-01

A fast measurement of pH of yogurt using Vis/NIR-spectroscopy techniques was established in order to measuring the acidity of yogurt rapidly. 27 samples selected separately from five different brands of yogurt were measured by Vis/NIR-spectroscopy. The pH of yogurt on positions scanned by spectrum was measured by a pH meter. The mathematical model between pH and Vis/NIR spectral measurements was established and developed based on partial least squares (PLS) by using Unscramble V9.2. Then 25 unknown samples from 5 different brands were predicted based on the mathematical model. The result shows that The correlation coefficient of pH based on PLS model is more than 0.890, and standard error of calibration (SEC) is 0.037, standard error of prediction (SEP) is 0.043. Through predicting the pH of 25 samples of yogurt from 5 different brands, the correlation coefficient between predictive value and measured value of those samples is more than 0918. The results show the good to excellent prediction performances. The Vis/NIR spectroscopy technique had a significant greater accuracy for determining the value of pH. It was concluded that the VisINIRS measurement technique can be used to measure pH of yogurt fast and accurately, and a new method for the measurement of pH of yogurt was established.

Evaluating the impact of distance measures on deforestation simulations in the fluvial landscapes of amazonia.

Science.gov (United States)

Salonen, Maria; Maeda, Eduardo Eiji; Toivonen, Tuuli

2014-10-01

Land use and land cover change (LUCC) models frequently employ different accessibility measures as a proxy for human influence on land change processes. Here, we simulate deforestation in Peruvian Amazonia and evaluate different accessibility measures as LUCC model inputs. We demonstrate how the selection, and different combinations, of accessibility measures impact simulation results. Out of the individual measures, time distance to market center catches the essential aspects of accessibility in our study area. The most accurate simulation is achieved when time distance to market center is used in association with distance to transport network and additional landscape variables. Although traditional Euclidean measures result in clearly lower simulation accuracy when used separately, the combination of two complementary Euclidean measures enhances simulation accuracy significantly. Our results highlight the need for site and context sensitive selection of accessibility variables. More sophisticated accessibility measures can potentially improve LUCC models' spatial accuracy, which often remains low.

A Scale Elasticity Measure for Directional Distance Function and its Dual: Theory and DEA Estimation

OpenAIRE

Valentin Zelenyuk

2012-01-01

In this paper we focus on scale elasticity measure based on directional distance function for multi-output-multi-input technologies, explore its fundamental properties and show its equivalence with the input oriented and output oriented scale elasticity measures. We also establish duality relationship between the scale elasticity measure based on the directional distance function with scale elasticity measure based on the profit function. Finally, we discuss the estimation issues of the scale...

In-situ position and vibration measurement of rough surfaces using laser Doppler distance sensors

Science.gov (United States)

Czarske, J.; Pfister, T.; Günther, P.; Büttner, L.

2009-06-01

In-situ measurement of distances and shapes as well as dynamic deformations and vibrations of fast moving and especially rotating objects, such as gear shafts and turbine blades, is an important task at process control. We recently developed a laser Doppler distance frequency sensor, employing two superposed fan-shaped interference fringe systems with contrary fringe spacing gradients. Via two Doppler frequency evaluations the non-incremental position (i.e. distance) and the tangential velocity of rotating bodies are determined simultaneously. The distance uncertainty is in contrast to e.g. triangulation in principle independent of the object velocity. This unique feature allows micrometer resolutions of fast moved rough surfaces. The novel sensor was applied at turbo machines in order to control the tip clearance. The measurements at a transonic centrifugal compressor were performed during operation at up to 50,000 rpm, i.e. 586 m/s velocity of the blade tips. Due to the operational conditions such as temperatures of up to 300 °C, a flexible and robust measurement system with a passive fiber-coupled sensor, using diffractive optics, has been realized. Since the tip clearance of individual blades could be temporally resolved an analysis of blade vibrations was possible. A Fourier transformation of the blade distances results in an average period of 3 revolutions corresponding to a frequency of 1/3 of the rotary frequency. Additionally, a laser Doppler distance sensor using two tilted fringe systems and phase evaluation will be presented. This phase sensor exhibits a minimum position resolution of σz = 140 nm. It allows precise in-situ shape measurements at grinding and turning processes.

Correlation Between Cometary Gas/Dust Ratios and Heliocentric Distance

Science.gov (United States)

Harrington, Olga; Womack, Maria; Lastra, Nathan

2017-10-01

We compiled CO-based gas/dust ratios for several comets out to heliocentric distances, rh, of 8 au to probe whether there is a noticeable change in comet behavior over the range that water-ice sublimation starts. Previously, gas/dust ratios were calculated for an ensemble of comets using Q(CO2)/efp values derived from infrared measurements, which showed that the gas/dust ratio follows a rh-2 within 4 AU, but is flat at greater distances (Bauer et al. 2015). Our project focuses on gas/dust ratios for which CO is assumed to be the dominant gas, in order to test whether similar breaks in slope occur for CO. The gas/dust ratios were calculated from measurements of CO production rates (mostly from millimeter-wavelength spectroscopy) and reflected sunlight of comets (mostly via reported visual magnitudes of dusty comets). We present our new CO-based gas/dust ratios at different heliocentric distances, compare them to existing CO2-based gas/dust ratios, and discuss implications for CO-driven and CO2-driven activity. We discuss O.H. acknowledges support from the Hartmann Student Travel Grant program. M.W. acknowledges support from NSF grant AST-1615917.

Measuring Algorithm for the Distance to a Preceding Vehicle on Curve Road Using On-Board Monocular Camera

Science.gov (United States)

Yu, Guizhen; Zhou, Bin; Wang, Yunpeng; Wun, Xinkai; Wang, Pengcheng

2015-12-01

Due to more severe challenges of traffic safety problems, the Advanced Driver Assistance Systems (ADAS) has received widespread attention. Measuring the distance to a preceding vehicle is important for ADAS. However, the existing algorithm focuses more on straight road sections than on curve measurements. In this paper, we present a novel measuring algorithm for the distance to a preceding vehicle on a curve road using on-board monocular camera. Firstly, the characteristics of driving on the curve road is analyzed and the recognition of the preceding vehicle road area is proposed. Then, the vehicle detection and distance measuring algorithms are investigated. We have verified these algorithms on real road driving. The experimental results show that this method proposed in the paper can detect the preceding vehicle on curve roads and accurately calculate the longitudinal distance and horizontal distance to the preceding vehicle.

Nano-viscosity of supercooled liquid measured by fluorescence correlation spectroscopy: Pressure and temperature dependence and the density scaling

Science.gov (United States)

Meier, G.; Gapinski, J.; Ratajczyk, M.; Lettinga, M. P.; Hirtz, K.; Banachowicz, E.; Patkowski, A.

2018-03-01

The Stokes-Einstein relation allows us to calculate apparent viscosity experienced by tracers in complex media on the basis of measured self-diffusion coefficients. Such defined nano-viscosity values can be obtained through single particle techniques, like fluorescence correlation spectroscopy (FCS) and particle tracking (PT). In order to perform such measurements, as functions of pressure and temperature, a new sample cell was designed and is described in this work. We show that this cell in combination with a long working distance objective of the confocal microscope can be used for successful FCS, PT, and confocal imaging experiments in broad pressure (0.1-100 MPa) and temperature ranges. The temperature and pressure dependent nano-viscosity of a van der Waals liquid obtained from the translational diffusion coefficient measured in this cell by means of FCS obeys the same scaling as the rotational relaxation and macro-viscosity of the system.

Carbon-deuterium rotational-echo double-resonance NMR spectroscopy of lyophilized aspartame formulations.

Science.gov (United States)

Luthra, Suman A; Utz, Marcel; Gorman, Eric M; Pikal, Michael J; Munson, Eric J; Lubach, Joseph W

2012-01-01

In this study, changes in the local conformation of aspartame were observed in annealed lyophilized glasses by monitoring changes in the distance between two labeled sites using C-(2)H rotational-echo double-resonance (REDOR) nuclear magnetic resonance (NMR) spectroscopy. Confirmation that the REDOR experiments were producing accurate distance measurement was ensured by measuring the (13)C-(15)N distance in glycine. The experiment was further verified by measuring the REDOR dephasing curve on (13)C-(2)H methionine. (13)C-(2)H REDOR dephasing curves were then measured on lyophilized aspartame-disaccharide formulations. In aspartame-sucrose formulation, the internuclear distances increased upon annealing, which correlated with decreased chemical reactivity. By contrast, annealing had only a minimal effect on the dephasing curve in aspartame-trehalose formulation. The results show that stability is a function of both mobility and local structure (conformation), even in a small molecule system such as lyophilized aspartame-sucrose. Copyright © 2011 Wiley-Liss, Inc.

Probing the nanoscale interaction forces and elastic properties of organic and inorganic materials using force-distance (F-D) spectroscopy

Science.gov (United States)

Vincent, Abhilash

Due to their therapeutic applications such as radical scavenging, MRI contrast imaging, Photoluminescence imaging, drug delivery, etc., nanoparticles (NPs) have a significant importance in bio-nanotechnology. The reason that prevents the utilizing NPs for drug delivery in medical field is mostly due to their biocompatibility issues (incompatibility can lead to toxicity and cell death). Changes in the surface conditions of NPs often lead to NP cytotoxicity. Investigating the role of NP surface properties (surface charges and surface chemistry) on their interactions with biomolecules (Cells, protein and DNA) could enhance the current understanding of NP cytotoxicity. Hence, it is highly beneficial to the nanotechnology community to bring more attention towards the enhancement of surface properties of NPs to make them more biocompatible and less toxic to biological systems. Surface functionalization of NPs using specific ligand biomolecules have shown to enhance the protein adsorption and cellular uptake through more favorable interaction pathways. Cerium oxide NPs (CNPs also known as nanoceria) are potential antioxidants in cell culture models and understanding the nature of interaction between cerium oxide NPs and biological proteins and cells are important due to their therapeutic application (especially in site specific drug delivery systems). The surface charges and surface chemistry of CNPs play a major role in protein adsorption and cellular uptake. Hence, by tuning the surface charges and by selecting proper functional molecules on the surface, CNPs exhibiting strong adhesion to biological materials can be prepared. By probing the nanoscale interaction forces acting between CNPs and protein molecules using Atomic Force Microscopy (AFM) based force-distance (F-D) spectroscopy, the mechanism of CNP-protein adsorption and CNP cellular uptake can be understood more quantitatively. The work presented in this dissertation is based on the application of AFM in

Mesoscopic Magnetic Resonance Spectroscopy with a Remote Spin Sensor

Science.gov (United States)

Xie, Tianyu; Shi, Fazhan; Chen, Sanyou; Guo, Maosen; Chen, Yisheng; Zhang, Yixing; Yang, Yu; Gao, Xingyu; Kong, Xi; Wang, Pengfei; Tateishi, Kenichiro; Uesaka, Tomohiro; Wang, Ya; Zhang, Bo; Du, Jiangfeng

2018-06-01

Quantum sensing based on nitrogen-vacancy (N -V ) centers in diamond has been developed as a powerful tool for microscopic magnetic resonance. However, the reported sensor-to-sample distance is limited within tens of nanometers resulting from the cubic decrease of the signal of spin fluctuation with the increasing distance. Here we extend the sensing distance to tens of micrometers by detecting spin polarization rather than spin fluctuation. We detect the mesoscopic magnetic resonance spectra of polarized electrons of a pentacene-doped crystal, measure its two typical decay times, and observe the optically enhanced spin polarization. This work paves the way for the N -V -based mesoscopic magnetic resonance spectroscopy and imaging at ambient conditions.

Comparing alternative approaches to measuring the geographical accessibility of urban health services: Distance types and aggregation-error issues

Directory of Open Access Journals (Sweden)

Riva Mylène

2008-02-01

Full Text Available Abstract Background Over the past two decades, geographical accessibility of urban resources for population living in residential areas has received an increased focus in urban health studies. Operationalising and computing geographical accessibility measures depend on a set of four parameters, namely definition of residential areas, a method of aggregation, a measure of accessibility, and a type of distance. Yet, the choice of these parameters may potentially generate different results leading to significant measurement errors. The aim of this paper is to compare discrepancies in results for geographical accessibility of selected health care services for residential areas (i.e. census tracts computed using different distance types and aggregation methods. Results First, the comparison of distance types demonstrates that Cartesian distances (Euclidean and Manhattan distances are strongly correlated with more accurate network distances (shortest network and shortest network time distances across the metropolitan area (Pearson correlation greater than 0.95. However, important local variations in correlation between Cartesian and network distances were observed notably in suburban areas where Cartesian distances were less precise. Second, the choice of the aggregation method is also important: in comparison to the most accurate aggregation method (population-weighted mean of the accessibility measure for census blocks within census tracts, accessibility measures computed from census tract centroids, though not inaccurate, yield important measurement errors for 5% to 10% of census tracts. Conclusion Although errors associated to the choice of distance types and aggregation method are only important for about 10% of census tracts located mainly in suburban areas, we should not avoid using the best estimation method possible for evaluating geographical accessibility. This is especially so if these measures are to be included as a dimension of the

Spectroscopy Apparatus for the Measurement of The Hyperfine Structure of Antihydrogen

CERN Document Server

Malbrunot, C.; Diermaier, M.; Dilaver, N.; Friedreich, S.; Kolbinger, B.; Lehner, S.; Lundmark, R.; Massiczek, O.; Radics, B.; Sauerzopf, C.; Simon, M.; Widmann, E.; Wolf, M.; Wünschek, B.; Zmeskal, J.

2014-02-04

The ASACUSA CUSP collaboration at the Antiproton Decelerator (AD) of CERN is planning to measure the ground-state hyperfine splitting of antihydrogen using an atomic spectroscopy beamline. We describe here the latest developments on the spectroscopy apparatus developed to be coupled to the antihydrogen production setup (CUSP).

Distance-Based Functional Diversity Measures and Their Decomposition: A Framework Based on Hill Numbers

Science.gov (United States)

Chiu, Chun-Huo; Chao, Anne

2014-01-01

Hill numbers (or the “effective number of species”) are increasingly used to characterize species diversity of an assemblage. This work extends Hill numbers to incorporate species pairwise functional distances calculated from species traits. We derive a parametric class of functional Hill numbers, which quantify “the effective number of equally abundant and (functionally) equally distinct species” in an assemblage. We also propose a class of mean functional diversity (per species), which quantifies the effective sum of functional distances between a fixed species to all other species. The product of the functional Hill number and the mean functional diversity thus quantifies the (total) functional diversity, i.e., the effective total distance between species of the assemblage. The three measures (functional Hill numbers, mean functional diversity and total functional diversity) quantify different aspects of species trait space, and all are based on species abundance and species pairwise functional distances. When all species are equally distinct, our functional Hill numbers reduce to ordinary Hill numbers. When species abundances are not considered or species are equally abundant, our total functional diversity reduces to the sum of all pairwise distances between species of an assemblage. The functional Hill numbers and the mean functional diversity both satisfy a replication principle, implying the total functional diversity satisfies a quadratic replication principle. When there are multiple assemblages defined by the investigator, each of the three measures of the pooled assemblage (gamma) can be multiplicatively decomposed into alpha and beta components, and the two components are independent. The resulting beta component measures pure functional differentiation among assemblages and can be further transformed to obtain several classes of normalized functional similarity (or differentiation) measures, including N-assemblage functional generalizations of

Distance-based functional diversity measures and their decomposition: a framework based on Hill numbers.

Directory of Open Access Journals (Sweden)

Chun-Huo Chiu

Full Text Available Hill numbers (or the "effective number of species" are increasingly used to characterize species diversity of an assemblage. This work extends Hill numbers to incorporate species pairwise functional distances calculated from species traits. We derive a parametric class of functional Hill numbers, which quantify "the effective number of equally abundant and (functionally equally distinct species" in an assemblage. We also propose a class of mean functional diversity (per species, which quantifies the effective sum of functional distances between a fixed species to all other species. The product of the functional Hill number and the mean functional diversity thus quantifies the (total functional diversity, i.e., the effective total distance between species of the assemblage. The three measures (functional Hill numbers, mean functional diversity and total functional diversity quantify different aspects of species trait space, and all are based on species abundance and species pairwise functional distances. When all species are equally distinct, our functional Hill numbers reduce to ordinary Hill numbers. When species abundances are not considered or species are equally abundant, our total functional diversity reduces to the sum of all pairwise distances between species of an assemblage. The functional Hill numbers and the mean functional diversity both satisfy a replication principle, implying the total functional diversity satisfies a quadratic replication principle. When there are multiple assemblages defined by the investigator, each of the three measures of the pooled assemblage (gamma can be multiplicatively decomposed into alpha and beta components, and the two components are independent. The resulting beta component measures pure functional differentiation among assemblages and can be further transformed to obtain several classes of normalized functional similarity (or differentiation measures, including N-assemblage functional

Electric field measurements in a xenon discharge using Spark spectroscopy

NARCIS (Netherlands)

Wagenaars, E.; Bowden, M.D.; Kroesen, G.M.W.

2005-01-01

Measurements of electric field distributions in a low-pressure xenon discharge are presented. The measurement technique is based on Stark spectroscopy, using a 2 + 1 excitation scheme with fluorescence dip detection. Electric fields can be measured by detecting Stark shifts of high-lying Rydberg

[Study on physical deviation factors on laser induced breakdown spectroscopy measurement].

Science.gov (United States)

Wan, Xiong; Wang, Peng; Wang, Qi; Zhang, Qing; Zhang, Zhi-Min; Zhang, Hua-Ming

2013-10-01

In order to eliminate the deviation between the measured LIBS spectral line and the standard LIBS spectral line, and improve the accuracy of elements measurement, a research of physical deviation factors in laser induced breakdown spectroscopy technology was proposed. Under the same experimental conditions, the relationship of ablated hole effect and spectral wavelength was tested, the Stark broadening data of Mg plasma laser induced breakdown spectroscopy with sampling time-delay from 1.00 to 3.00 micros was also studied, thus the physical deviation influences such as ablated hole effect and Stark broadening could be obtained while collecting the spectrum. The results and the method of the research and analysis can also be applied to other laser induced breakdown spectroscopy experiment system, which is of great significance to improve the accuracy of LIBS elements measuring and is also important to the research on the optimum sampling time-delay of LIBS.

Application of digital image correlation for long-distance bridge deflection measurement

Science.gov (United States)

Tian, Long; Pan, Bing; Cai, Youfa; Liang, Hui; Zhao, Yan

2013-06-01

Due to its advantages of non-contact, full-field and high-resolution measurement, digital image correlation (DIC) method has gained wide acceptance and found numerous applications in the field of experimental mechanics. In this paper, the application of DIC for real-time long-distance bridge deflection detection in outdoor environments is studied. Bridge deflection measurement using DIC in outdoor environments is more challenging than regular DIC measurements performed under laboratory conditions. First, much more image noise due to variations in ambient light will be presented in the images recorded in outdoor environments. Second, how to select the target area becomes a key factor because long-distance imaging results in a large field of view of the test object. Finally, the image acquisition speed of the camera must be high enough (larger than 100 fps) to capture the real-time dynamic motion of a bridge. In this work, the above challenging issues are addressed and several improvements were made to DIC method. The applicability was demonstrated by real experiments. Experimental results indicate that the DIC method has great potentials in motion measurement in various large building structures.

Distance measurement using frequency-modulated continuous-wave ladar with calibration by a femtosecond frequency comb

Science.gov (United States)

Liu, Yang; Yang, Linghui; Lin, Jiarui; Zhu, Jigui

2018-01-01

Precise distance measurement is of interest for large-scale manufacturing, future space satellite missions, and other industrial applications. The ranging system with femtosecond optical frequency comb (FOFC) could offer high accuracy, stability and direct traceability to SI definition of the meter. Here, we propose a scheme for length measurement based on the frequency-modulated continuous-wave (FMCW) ladar with a FOFC. In this scheme, the reference interferometer in the FMCW ladar is calibrated by the intensity detection using the FOFC in the time domain within an optical wavelength resolution. With analysis of the theoretical model, this system has the potential to a high-speed, high-accuracy absolute distance measurement. Then, based on the experimental results, the evaluation of the performance of the calibration of the reference arm is discussed. In addition, the performance of this system is evaluated by a single position measurement with different tuning velocities of wavelength. The experimental results show that the reproducibility of the distance measurement is 10-5 level.

Laser distance measurement using a newly developed composite-type optical fiberscope for fetoscopic laser surgery

Science.gov (United States)

Seki, Takeshi; Oka, Kiyoshi; Naganawa, Akihiro; Yamashita, Hiromasa; Kim, Keri; Chiba, Toshio

2010-10-01

Twin-twin transfusion syndrome (TTTS) is a condition of twins disproportionately sharing blood by the communicating vessels in the shared placenta and resulting in the significantly high fetal and perinatal mortality rate. Fetoscopic laser surgery is performed to block these communicating vessels. It is difficult, however, to perceive the distance from the tip of the fetoscope to the placental surface with only a two-dimensional fetoscopic view. When the distance is too short it causes excessive irradiation and even the risk of inadvertent damage to the placenta. On the other hand, not only target vessels but also adjacent tissues can be irradiated when it is too long. We have developed a composite-type optical fiberscope (COF) that was able to observe the target area and also to perform laser irradiation at the same time. In this paper, we studied a method to estimate the distance from the tip of the COF to the target area. We combined the COF with a laser blood-flow meter. Using laser light from the meter, we measured the total amount of light received ("REFLEX") and estimated the relation between the "REFLEX" value and the laser irradiation distance. Further in vivo experiments were subsequently carried out using porcine mesenteric blood vessels. The results showed that the distance and the "REFLEX" value were inversely proportional, irrespective of the experimental environment (e.g. in air, water and amniotic fluid-like solution) and the target object. In the in vivo experiments, we quantitatively measured the distance within an accuracy of ±1 mm (approximately 10%). In conclusion, our new system was able to measure the distance in vivo enabling a surgeon to safely and effectively perform laser irradiation at a suitable distance. The system can be used not only for fetoscopic surgery but also for general endoscopic surgery.

Source-to-detector distance and beam center do not affect radiographic measurements of acetabular morphology

International Nuclear Information System (INIS)

Goldman, Ashton H.; Hoover, Kevin B.

2017-01-01

Multiple radiographic acquisition techniques have been evaluated for their effect on measurements of acetabular morphology. This cadaveric study examined the effect of two acquisition parameters not previously evaluated: beam center position and source-to-detector distance. This study also evaluated the effect of reader differences on measurements. Following calibration of measurements between two readers using five clinical radiographs (training), radiographs were obtained from two cadavers using four different source-to-detector distances and three different radiographic centers for a total of 12 radiographic techniques (experimental). Two physician readers acquired four types of measurements from each cadaver radiograph: lateral center edge angle, peak-to-edge distance, Sharp's angle, and the Tonnis angle. All measurements were evaluated for intra-class correlation coefficient (ICC), kappa statistics for hip dysplasia, and factors that resulted in measurement differences using a mixed statistical model. After training of the two physician readers, there was strong agreement in their hip morphology measurements (ICC 0.84-0.93), agreement in the presence of hip dysplasia (κ = 0.58-1.0), and no measurement difference between physician readers (p = 0.12-1.0). Experimental cadaver measurements showed moderate-to-strong agreement of the readers (ICC 0.74-0.93) and complete agreement on dysplasia (κ = 1). After accounting for reader and radiographic technique, there was no difference in hip morphology measurements (p = 0.83-0.99). In this cadaveric study, measurements of hip morphology were not affected by varying source-to-detector distance or beam center. We conclude that these acquisition parameters are not likely to affect the diagnosis of hip dysplasia in a clinical setting. (orig.)

Source-to-detector distance and beam center do not affect radiographic measurements of acetabular morphology

Energy Technology Data Exchange (ETDEWEB)

Goldman, Ashton H. [Department of Orthopaedic Surgery, Virginia Commonwealth University, Richmond, VA (United States); Hoover, Kevin B. [Virginia Commonwealth University, Department of Radiology, 1250 E Marshall St. 3rd Floor, PO Box 980615, Richmond, VA (United States)

2017-04-15

Multiple radiographic acquisition techniques have been evaluated for their effect on measurements of acetabular morphology. This cadaveric study examined the effect of two acquisition parameters not previously evaluated: beam center position and source-to-detector distance. This study also evaluated the effect of reader differences on measurements. Following calibration of measurements between two readers using five clinical radiographs (training), radiographs were obtained from two cadavers using four different source-to-detector distances and three different radiographic centers for a total of 12 radiographic techniques (experimental). Two physician readers acquired four types of measurements from each cadaver radiograph: lateral center edge angle, peak-to-edge distance, Sharp's angle, and the Tonnis angle. All measurements were evaluated for intra-class correlation coefficient (ICC), kappa statistics for hip dysplasia, and factors that resulted in measurement differences using a mixed statistical model. After training of the two physician readers, there was strong agreement in their hip morphology measurements (ICC 0.84-0.93), agreement in the presence of hip dysplasia (κ = 0.58-1.0), and no measurement difference between physician readers (p = 0.12-1.0). Experimental cadaver measurements showed moderate-to-strong agreement of the readers (ICC 0.74-0.93) and complete agreement on dysplasia (κ = 1). After accounting for reader and radiographic technique, there was no difference in hip morphology measurements (p = 0.83-0.99). In this cadaveric study, measurements of hip morphology were not affected by varying source-to-detector distance or beam center. We conclude that these acquisition parameters are not likely to affect the diagnosis of hip dysplasia in a clinical setting. (orig.)

Recoil distance measurements of litetimes of levels in 2120F and 16N

International Nuclear Information System (INIS)

Kozub, R.L.; Mateja, J.F.; Lin, J.; Lister, C.J.; Olness, J.; Warburton, E.K.; Bynum, M.R.; Matthews, T.L.

1981-01-01

The previously-reported measurements of meanlives of 20 21 F levels using the recoil-distance method (RDM) and 18 O + 7 Li reactions have been repeated using improved experimental techniques. In addition, the lifetimes of two 16 N levels were measured, using the same experimental setup and 11 B + 7 Li reactions. Data were taken using the BNL precision plunger, in which were mounted a stretched Ta stopper foil (approx. 20 /sub cm 2 //sup mg/ thick) and a 300 μg/cm 2 - thick Li target condensed onto a stretched, 1.4 mg/cm 2 - thick Ta backing. Changes in target-to-stopper distance (d) could be controlled to an accuracy of about +- 1 μm, and were monitored by measuring target-to-stopper capacitance

A Game Map Complexity Measure Based on Hamming Distance

Science.gov (United States)

Li, Yan; Su, Pan; Li, Wenliang

With the booming of PC game market, Game AI has attracted more and more researches. The interesting and difficulty of a game are relative with the map used in game scenarios. Besides, the path-finding efficiency in a game is also impacted by the complexity of the used map. In this paper, a novel complexity measure based on Hamming distance, called the Hamming complexity, is introduced. This measure is able to estimate the complexity of binary tileworld. We experimentally demonstrated that Hamming complexity is highly relative with the efficiency of A* algorithm, and therefore it is a useful reference to the designer when developing a game map.

Plasma-cavity ringdown spectroscopy for analytical measurement: Progress and prospectives

Science.gov (United States)

Zhang, Sida; Liu, Wei; Zhang, Xiaohe; Duan, Yixiang

2013-07-01

Plasma-cavity ringdown spectroscopy is a powerful absorption technique for analytical measurement. It combines the inherent advantages of high sensitivity, absolute measurement, and relative insensitivity to light source intensity fluctuations of the cavity ringdown technique with use of plasma as an atomization/ionization source. In this review, we briefly describe the background and principles of plasma-cavity ringdown spectroscopy(CRDS) technology, the instrumental components, and various applications. The significant developments of the plasma sources, lasers, and cavity optics are illustrated. Analytical applications of plasma-CRDS for elemental detection and isotopic measurement in atomic spectrometry are outlined in this review. Plasma-CRDS is shown to have a promising future for various analytical applications, while some further efforts are still needed in fields such as cavity design, plasma source design, instrumental improvement and integration, as well as potential applications in radical and molecular measurements.

A clinical distance measure for evaluating treatment plan quality difference with Pareto fronts in radiotherapy

Directory of Open Access Journals (Sweden)

Kristoffer Petersson

2017-07-01

Full Text Available We present a clinical distance measure for Pareto front evaluation studies in radiotherapy, which we show strongly correlates (r = 0.74 and 0.90 with clinical plan quality evaluation. For five prostate cases, sub-optimal treatment plans located at a clinical distance value of >0.32 (0.28–0.35 from fronts of Pareto optimal plans, were assessed to be of lower plan quality by our (12 observers (p < .05. In conclusion, the clinical distance measure can be used to determine if the difference between a front and a given plan (or between different fronts corresponds to a clinically significant plan quality difference.

Conformational changes in human serum albumin studied by fluorescence and absorption spectroscopy. Distance measurements as a function of pH and fatty acids

DEFF Research Database (Denmark)

Honoré, B; Pedersen, A O

1989-01-01

pH- and fatty acid-induced conformational changes in human serum albumin were investigated by fluorescence-energy transfer, determining the distance between Trp-214 and bound bilirubin at 25 degrees C. This distance changes significantly with the pH, being 2.52 +/- 0.01 nm at pH 6, 2.31 +/- 0.04 nm...... at pH 9, 2.13 +/- 0.07 nm at pH 11.0 and 2.77 nm at pH 11.9. The influence of different fatty acids on the distance was also determined. At pH 7.4 medium-chain fatty acids seem to increase this distance, whereas long-chain fatty acids, at low concentrations, decrease the distance between the two...... chromophores. The contraction of the protein carrying long-chain saturated fatty acids is even more pronounced at pH 9. Udgivelsesdato: 1989-Feb-15...

Spatio-Temporal Image Correlation Spectroscopy Measurements of Flow Demonstrated in Microfluidic Channels

Science.gov (United States)

Rossow, Molly; Mantulin, William W.; Gratton, Enrico

2009-01-01

Accurate blood flow measurements during surgery can improve the operations chance of success. We developed Near-infrared Spatio-Temporal Image Spectroscopy (NIR-STICS), which has the potential to make blood flow measurements that are difficult to accomplish with existing methods. Specifically, we propose the technique and we show feasibility on phantom measurements. NIR-STICS has the potential of measuring the fluid velocity in small blood vessels (less than 1mm in diameter) and of creating a map of blood flow rates over an area of approximately 1cm2. NIR-STICS employs near-infrared spectroscopy to probe inside blood vessel walls and spatio-temporal image correlation spectroscopy to directly—without the use of a model—extract fluid velocity from the fluctuations within an image. Here we present computer simulations and experiments on a phantom system that demonstrate the effectiveness of NIR-STICS. PMID:19405744

Lifetime measurements using the recoil distance method—achievements and perspectives

Science.gov (United States)

Krücken, R.

2001-07-01

The recoil distance method (RDM) for measuring pico-second nuclear level lifetimes and its use in nuclear structure studies is reviewed and perspectives for the future are presented. High precision measurements in the mass-130 region, studies of multi-phonon states in rare earth nuclei, the investigation of shape coexistence and the recently discovered phenomenon of "magnetic rotation" are reviewed. Prospects for lifetime measurements in exotic regions of nuclei such as the measurement of lifetimes in neutron rich nuclei populated via spontaneous and heavy-ion induced fission are discussed. Other prospects include the use of the RDM technique in conjunction with recoil separators. The relevance of these techniques for experiments with radioactive ion beams will be discussed.

Lifetime measurements using the recoil distance method - achievements and perspectives

International Nuclear Information System (INIS)

Kruecken, R.

2001-01-01

The recoil distance method (RDM) for measuring pico-second nuclear level lifetimes and its use in nuclear structure studies is reviewed and perspectives for the future are presented. High precision measurements in the mass-130 region, studies of multi-phonon states in rare earth nuclei, the investigation of shape coexistence and the recently discovered phenomenon of 'magnetic rotation' are reviewed. Prospects for lifetime measurements in exotic regions of nuclei such as the measurement of lifetimes in neutron rich nuclei populated via spontaneous and heavy-ion induced fission are discussed. Other prospects include the use of the RDM technique in conjunction with recoil separators. The relevance of these techniques for experiments with radioactive ion beams will be discussed

Distance Measurement Methods for Improved Insider Threat Detection

Directory of Open Access Journals (Sweden)

Owen Lo

2018-01-01

Full Text Available Insider threats are a considerable problem within cyber security and it is often difficult to detect these threats using signature detection. Increasing machine learning can provide a solution, but these methods often fail to take into account changes of behaviour of users. This work builds on a published method of detecting insider threats and applies Hidden Markov method on a CERT data set (CERT r4.2 and analyses a number of distance vector methods (Damerau–Levenshtein Distance, Cosine Distance, and Jaccard Distance in order to detect changes of behaviour, which are shown to have success in determining different insider threats.

The Hetu'u Global Network: Measuring the Distance to the Sun with the Transit of Venus

Science.gov (United States)

Rodriguez, David; Faherty, J.

2013-01-01

In the spirit of historic astronomical endeavors, we invited school groups across the globe to collaborate in a solar distance measurement using the 2012 transit of Venus. In total, our group (stationed at Easter Island, Chile) recruited 19 school groups spread over 6 continents and 10 countries to participate in our Hetu’u Global Network. Applying the methods of French astronomer Joseph-Nicolas Delisle, we used individual second and third Venus-Sun contact times to calculate the distance to the Sun. Ten of the sites in our network had amiable weather; 8 of which measured second contact and 5 of which measured third contact leading to consistent solar distance measurements of 152+/-30 million km and 163+/-30 million km respectively. The distance to the Sun at the time of the transit was 152.25 million km; therefore, our measurements are also consistent within 1-sigma of the known value. The goal of our international school group network was to inspire the next generation of scientists using the excitement and accessibility of such a rare astronomical event. In the process, we connected hundreds of participating students representing a diverse, multi-cultural group with differing political, economic, and racial backgrounds.

The Czech national long distances measuring standard Koštice - State of play

Directory of Open Access Journals (Sweden)

Ladislav Červinka

2009-11-01

Full Text Available This article gives information about new Czech national long distances measuring standard, which has been preparedat the distance base near the Koštice village. Submitter of the project is the Czech Office for Standards, Metrology and Testing.Research and document preparation for creation of the measuring standard were ensured by the Research Institute of Geodesy,Topography and Cartography. Interlaboratory comparisons were made by staff of the Bundeswehr University in Munich. The paperreports about works, which will be carried out on national standard in the second half of this year. Purpose of this works is to improvecharacteristics of accuracy of national etalon.

Absolute distance measurement with extension of nonambiguity range using the frequency comb of a femtosecond laser

Science.gov (United States)

Jang, Yoon-Soo; Lee, Keunwoo; Han, Seongheum; Lee, Joohyung; Kim, Young-Jin; Kim, Seung-Woo

2014-12-01

We revisit the method of synthetic wavelength interferometry (SWI) for absolute measurement of long distances using the radio-frequency harmonics of the pulse repetition rate of a mode-locked femtosecond laser. Our intention here is to extend the nonambiguity range (NAR) of the SWI method using a coarse virtual wavelength synthesized by shifting the pulse repetition rate. The proposed concept of NAR extension is experimentally verified by measuring a ˜13-m distance with repeatability of 9.5 μm (root-mean-square). The measurement precision is estimated to be 31.2 μm in comparison with an incremental He-Ne laser interferometer. This extended SWI method is found to be well suited for long-distance measurements demanded in the fields of large-scale precision engineering, geodetic survey, and future space missions.

A Chroma-based Tempo-insensitive Distance Measure for Cover Song Identification

DEFF Research Database (Denmark)

Jensen, Jesper Højvang; Ellis, Dan P. W.; Christensen, Mads Græsbøll

In the context of music, a cover version is a remake of a song, often with significant stylistic variation. In this paper we describe a distance measure between sampled audio files that is designed to be insensitive to instrumentation, time shift, temporal scaling and transpositions. The algorithm...

Hyperfine structure of 147,149Sm measured using saturated absorption spectroscopy in combination with resonance-ionization mass spectroscopy

International Nuclear Information System (INIS)

Park, Hyunmin; Lee, Miran; Rhee, Yongjoo

2003-01-01

The hyperfine structures of four levels of the Sm isotopes have been measured by means of diode-laser-based Doppler-free saturated absorption spectroscopy in combination with a diode-laser-initiated resonance-ionization mass spectroscopy. It was demonstrated that combining the two spectroscopic methods was very effective for the identification and accurate measurement of the spectral lines of atoms with several isotopes, such as the rare-earth elements. From the obtained spectra, the hyperfine constants A and B for the odd-mass isotopes 147 Sm and 149 Sm were determined for four upper levels of the studied transitions.

Recoil distance method lifetime measurements at TRIUMF-ISAC using the TIGRESS Integrated Plunger

Science.gov (United States)

Chester, A.; Ball, G. C.; Bernier, N.; Cross, D. S.; Domingo, T.; Drake, T. E.; Evitts, L. J.; Garcia, F. H.; Garnsworthy, A. B.; Hackman, G.; Hallam, S.; Henderson, J.; Henderson, R.; Krücken, R.; MacConnachie, E.; Moukaddam, M.; Padilla-Rodal, E.; Paetkau, O.; Pore, J. L.; Rizwan, U.; Ruotsalainen, P.; Shoults, J.; Smallcombe, J.; Smith, J. K.; Starosta, K.; Svensson, C. E.; Van Wieren, K.; Williams, J.; Williams, M.

2018-02-01

The TIGRESS Integrated Plunger device (TIP) has been developed for recoil distance method (RDM) lifetime measurements using the TIGRESS array of HPGe γ-ray detectors at TRIUMF's ISAC-II facility. A commissioning experiment was conducted utilizing a 250 MeV 84Kr beam at ≈ 2 × 108 particles per second. The 84Kr beam was Coulomb excited to the 21+ state on a movable 27Al target. A thin Cu foil fixed downstream from the target was used as a degrader. Excited nuclei emerged from the target and decayed by γ-ray emission at a distance determined by their velocity and the lifetime of the 21+ state. The ratio of decays which occur between the target and degrader to those occurring after traversing the degrader changes as a function of the target-degrader separation distance. Gamma-ray spectra at 13 target-degrader separation distances were measured and compared to simulated lineshapes to extract the lifetime. The result of τ = 5 . 541 ± 0 . 013(stat.) ± 0 . 063(sys.) ps is shorter than the literature value of 5 . 84 ± 0 . 18 ps with a reduction in uncertainty by a factor of approximately two. The TIP plunger device, experimental technique, analysis tools, and result are discussed.

Standoff spectroscopy using a conditioned target

Science.gov (United States)

Van Neste, Charles W [Kingston, TN; Morales-Rodriguez, Marissa E [Knoxville, TN; Senesac, Lawrence R [Knoxville, TN; Thundat, Thomas G [Knoxville, TN

2011-12-20

A system and method are disclosed for standoff spectroscopy of molecules (e.g. from a residue) on a surface from a distance. A source emits radiation that modifies or conditions the residue, such as through photodecomposition. A spectral generating source measures a spectrum of the residue before and after the residue is exposed to the radiation from that source. The two spectra are compared to produce a distinct identification of the residues on the surface or identify certain properties of the residue.

Combined multi-distance frequency domain and diffuse correlation spectroscopy system with simultaneous data acquisition and real-time analysis.

Science.gov (United States)

Carp, Stefan A; Farzam, Parisa; Redes, Norin; Hueber, Dennis M; Franceschini, Maria Angela

2017-09-01

Frequency domain near infrared spectroscopy (FD-NIRS) and diffuse correlation spectroscopy (DCS) have emerged as synergistic techniques for the non-invasive assessment of tissue health. Combining FD-NIRS oximetry with DCS measures of blood flow, the tissue oxygen metabolic rate can be quantified, a parameter more closely linked to underlying physiology and pathology than either NIRS or DCS estimates alone. Here we describe the first commercially available integrated instrument, called the "MetaOx", designed to enable simultaneous FD-NIRS and DCS measurements at rates of 10 + Hz, and offering real-time data evaluation. We show simultaneously acquired characterization data demonstrating performance equivalent to individual devices and sample in vivo measurements of pulsation resolved blood flow, forearm occlusion hemodynamic changes and muscle oxygen metabolic rate monitoring during stationary bike exercise.

Measuring distance “as the horse runs”: Cross-scale comparison of terrain-based metrics

Science.gov (United States)

Buttenfield, Barbara P.; Ghandehari, M; Leyk, S; Stanislawski, Larry V.; Brantley, M E; Qiang, Yi

2016-01-01

Distance metrics play significant roles in spatial modeling tasks, such as flood inundation (Tucker and Hancock 2010), stream extraction (Stanislawski et al. 2015), power line routing (Kiessling et al. 2003) and analysis of surface pollutants such as nitrogen (Harms et al. 2009). Avalanche risk is based on slope, aspect, and curvature, all directly computed from distance metrics (Gutiérrez 2012). Distance metrics anchor variogram analysis, kernel estimation, and spatial interpolation (Cressie 1993). Several approaches are employed to measure distance. Planar metrics measure straight line distance between two points (“as the crow flies”) and are simple and intuitive, but suffer from uncertainties. Planar metrics assume that Digital Elevation Model (DEM) pixels are rigid and flat, as tiny facets of ceramic tile approximating a continuous terrain surface. In truth, terrain can bend, twist and undulate within each pixel.Work with Light Detection and Ranging (lidar) data or High Resolution Topography to achieve precise measurements present challenges, as filtering can eliminate or distort significant features (Passalacqua et al. 2015). The current availability of lidar data is far from comprehensive in developed nations, and non-existent in many rural and undeveloped regions. Notwithstanding computational advances, distance estimation on DEMs has never been systematically assessed, due to assumptions that improvements are so small that surface adjustment is unwarranted. For individual pixels inaccuracies may be small, but additive effects can propagate dramatically, especially in regional models (e.g., disaster evacuation) or global models (e.g., sea level rise) where pixels span dozens to hundreds of kilometers (Usery et al 2003). Such models are increasingly common, lending compelling reasons to understand shortcomings in the use of planar distance metrics. Researchers have studied curvature-based terrain modeling. Jenny et al. (2011) use curvature to generate

The measurement of X-rays radiation temperature with a new developed filter-fluorescence spectroscopy

International Nuclear Information System (INIS)

Zhang Chuanfei; Lin Libin; Lou Fuhong; Peng Taiping

2001-01-01

The author introduces how to measure the energy spectra of X-rays by filter-fluorescence spectroscopy. The design principle and structure of new-developed double diaphragms and filter-fluorescence spectroscopy with 5 channels are depicted. The parameters of optimized spectroscopy by numerical method are given. The filter-fluorescence spectroscopy designed according as Rousseau balance principle improves signal-noises ratio

How the Measurement of Store Choice Behaviour Moderates the Relationship between Distance and Store Choice Behaviour

DEFF Research Database (Denmark)

Hansen, Torben; Cumberland, Flemming; Solgaard, Hans Stubbe

2013-01-01

The influence of distance on consumer store choice behaviour has been considered in many studies. In that respect, frequency and budget share are frequently used methods of measurement to determine the consumer's store choice behavour. In this study, we propose that the significance of distance...... is influenced by the way in which store choice behaviour is conceptualized. A survey among 631 consuemrs was performed in order to examine the research proposition. Structural equation results suggest that the negative effect of distance on store choice behaviour is larger when store choice behaviour...... is measured as number of visits to a particular store than wehen store cjoice behaviour is measured as the percentage of budget spend at a particular store. Our results indicate that researchers should carefully consider the measurement of store choice behaviour when carrying out empirical research invlving...

Censoring distances based on labeled cortical distance maps in cortical morphometry.

Science.gov (United States)

Ceyhan, Elvan; Nishino, Tomoyuki; Alexopolous, Dimitrios; Todd, Richard D; Botteron, Kelly N; Miller, Michael I; Ratnanather, J Tilak

2013-01-01

It has been demonstrated that shape differences in cortical structures may be manifested in neuropsychiatric disorders. Such morphometric differences can be measured by labeled cortical distance mapping (LCDM) which characterizes the morphometry of the laminar cortical mantle of cortical structures. LCDM data consist of signed/labeled distances of gray matter (GM) voxels with respect to GM/white matter (WM) surface. Volumes and other summary measures for each subject and the pooled distances can help determine the morphometric differences between diagnostic groups, however they do not reveal all the morphometric information contained in LCDM distances. To extract more information from LCDM data, censoring of the pooled distances is introduced for each diagnostic group where the range of LCDM distances is partitioned at a fixed increment size; and at each censoring step, the distances not exceeding the censoring distance are kept. Censored LCDM distances inherit the advantages of the pooled distances but also provide information about the location of morphometric differences which cannot be obtained from the pooled distances. However, at each step, the censored distances aggregate, which might confound the results. The influence of data aggregation is investigated with an extensive Monte Carlo simulation analysis and it is demonstrated that this influence is negligible. As an illustrative example, GM of ventral medial prefrontal cortices (VMPFCs) of subjects with major depressive disorder (MDD), subjects at high risk (HR) of MDD, and healthy control (Ctrl) subjects are used. A significant reduction in laminar thickness of the VMPFC in MDD and HR subjects is observed compared to Ctrl subjects. Moreover, the GM LCDM distances (i.e., locations with respect to the GM/WM surface) for which these differences start to occur are determined. The methodology is also applicable to LCDM-based morphometric measures of other cortical structures affected by disease.

Censoring Distances Based on Labeled Cortical Distance Maps in Cortical Morphometry

Directory of Open Access Journals (Sweden)

Elvan eCeyhan

2013-10-01

Full Text Available It has been demonstrated that shape differences are manifested in cortical structures due to neuropsychiatric disorders. Such morphometric differences can be measured by labeled cortical distance mapping (LCDM which characterizes the morphometry of the laminar cortical mantle of cortical structures. LCDM data consist of signed/labeled distances of gray matter (GM voxels with respect to GM/white matter (WM surface. Volumes and other summary measures for each subject and the pooled distances can help determine the morphometric differences between diagnostic groups, however they do not reveal all the morphometric information con-tained in LCDM distances. To extract more information from LCDM data, censoring of the pooled distances is introduced for each diagnostic group where the range of LCDM distances is partitioned at a fixed increment size; and at each censoring step, the distances not exceeding the censoring distance are kept. Censored LCDM distances inherit the advantages of the pooled distances but also provide information about the location of morphometric differences which cannot be obtained from the pooled distances. However, at each step, the censored distances aggregate, which might confound the results. The influence of data aggregation is investigated with an extensive Monte Carlo simulation analysis and it is demonstrated that this influence is negligible. As an illustrative example, GM of ventral medial prefrontal cortices (VMPFCs of subjects with major depressive disorder (MDD, subjects at high risk (HR of MDD, and healthy control (Ctrl subjects are used. A significant reduction in laminar thickness of the VMPFC in MDD and HR subjects is observed compared to Ctrl subjects. Moreover, the GM LCDM distances (i.e., locations with respect to the GM/WM surface for which these differences start to occur are determined. The methodology is also applicable to LCDM-based morphometric measures of other cortical structures affected by disease.

Oxygen measurement by multimode diode lasers employing gas correlation spectroscopy.

Science.gov (United States)

Lou, Xiutao; Somesfalean, Gabriel; Chen, Bin; Zhang, Zhiguo

2009-02-10

Multimode diode laser (MDL)-based correlation spectroscopy (COSPEC) was used to measure oxygen in ambient air, thereby employing a diode laser (DL) having an emission spectrum that overlaps the oxygen absorption lines of the A band. A sensitivity of 700 ppm m was achieved with good accuracy (2%) and linearity (R(2)=0.999). For comparison, measurements of ambient oxygen were also performed by tunable DL absorption spectroscopy (TDLAS) technique employing a vertical cavity surface emitting laser. We demonstrate that, despite slightly degraded sensitivity, the MDL-based COSPEC-based oxygen sensor has the advantages of high stability, low cost, ease-of-use, and relaxed requirements in component selection and instrument buildup compared with the TDLAS-based instrument.

An uncertainty importance measure using a distance metric for the change in a cumulative distribution function

International Nuclear Information System (INIS)

Chun, Moon-Hyun; Han, Seok-Jung; Tak, Nam-IL

2000-01-01

A simple measure of uncertainty importance using the entire change of cumulative distribution functions (CDFs) has been developed for use in probability safety assessments (PSAs). The entire change of CDFs is quantified in terms of the metric distance between two CDFs. The metric distance measure developed in this study reflects the relative impact of distributional changes of inputs on the change of an output distribution, while most of the existing uncertainty importance measures reflect the magnitude of relative contribution of input uncertainties to the output uncertainty. The present measure has been evaluated analytically for various analytical distributions to examine its characteristics. To illustrate the applicability and strength of the present measure, two examples are provided. The first example is an application of the present measure to a typical problem of a system fault tree analysis and the second one is for a hypothetical non-linear model. Comparisons of the present result with those obtained by existing uncertainty importance measures show that the metric distance measure is a useful tool to express the measure of uncertainty importance in terms of the relative impact of distributional changes of inputs on the change of an output distribution

The influence of target properties on nuclear spectroscopy measurements

International Nuclear Information System (INIS)

Dionisio, J.S.; Vieu, C.; Lagrange, J.M.; Pautrat, M.; Vanhorenbeeck, J.; Passoja, A.

1988-01-01

A broad review of different kinds of in-beam nuclear spectroscopy measurements particularly influenced by the target properties is outlined. To illustrate such an influence a few typical examples of in-beam electron and gamma-ray spectroscopy measurements, performed at the Orsay MP Tandem accelerator, are reported. In particular several applications of the recoil ion catcher method in the study of short-lived nuclear isomers (with half-lives between ten and few hundred nanoseconds) are briefly described. This method is operated mostly with a pulsed heavy ion beam, bombarding a thin self-supported target but avoiding hitting the catcher foil. Moreover, the time of flight filtering properties of this experimental device is improved by a fast detection of compound nucleus deexcitation (performed with an array of several BaF 2 crystals). This kind of measurement shows clearly the importance of the target qualities as well as the need of good focusing properties and time structure for the accelerated particle beam. Finally, the required characteristics of the targets and recoil stopper foils needed for these measurements (and similar ones performed with the recoil ion shadow method) are analyzed in detail for a few typical experimental arrangements. (author). Abstract only

Student Performance in Measuring Distance with Wavelengths in Various Settings

Science.gov (United States)

White, Gary

2015-04-01

When physics students are asked to measure the distance between two fixed locations using a pre-defined wavelength as a ruler, there is a surprising failure rate, at least partially due to the fact that the ``ruler'' to be used is not fixed in length (see ``Is a Simple Measurement Task a Roadblock to Student Understanding of Wave Phenomena?,'' by and references therein). I will show some data from introductory classes (algebra- and calculus-based) that replicate this result, and also show some interesting features when comparing a setting involving slinkies with a setting involving surface waves on water.

Measurement of the phase difference between short- and long-distance amplitudes in the [Formula: see text] decay.

Science.gov (United States)

Aaij, R; Adeva, B; Adinolfi, M; Ajaltouni, Z; Akar, S; Albrecht, J; Alessio, F; Alexander, M; Ali, S; Alkhazov, G; Alvarez Cartelle, P; Alves, A A; Amato, S; Amerio, S; Amhis, Y; An, L; Anderlini, L; Andreassi, G; Andreotti, M; Andrews, J E; Appleby, R B; Archilli, F; d'Argent, P; Arnau Romeu, J; Artamonov, A; Artuso, M; Aslanides, E; Auriemma, G; Baalouch, M; Babuschkin, I; Bachmann, S; Back, J J; Badalov, A; Baesso, C; Baker, S; Balagura, V; Baldini, W; Barlow, R J; Barschel, C; Barsuk, S; Barter, W; Baszczyk, M; Batozskaya, V; Batsukh, B; Battista, V; Bay, A; Beaucourt, L; Beddow, J; Bedeschi, F; Bediaga, I; Bel, L J; Bellee, V; Belloli, N; Belous, K; Belyaev, I; Ben-Haim, E; Bencivenni, G; Benson, S; Berezhnoy, A; Bernet, R; Bertolin, A; Betancourt, C; Betti, F; Bettler, M-O; van Beuzekom, M; Bezshyiko, Ia; Bifani, S; Billoir, P; Bird, T; Birnkraut, A; Bitadze, A; Bizzeti, A; Blake, T; Blanc, F; Blouw, J; Blusk, S; Bocci, V; Boettcher, T; Bondar, A; Bondar, N; Bonivento, W; Bordyuzhin, I; Borgheresi, A; Borghi, S; Borisyak, M; Borsato, M; Bossu, F; Boubdir, M; Bowcock, T J V; Bowen, E; Bozzi, C; Braun, S; Britsch, M; Britton, T; Brodzicka, J; Buchanan, E; Burr, C; Bursche, A; Buytaert, J; Cadeddu, S; Calabrese, R; Calvi, M; Calvo Gomez, M; Camboni, A; Campana, P; Campora Perez, D H; Capriotti, L; Carbone, A; Carboni, G; Cardinale, R; Cardini, A; Carniti, P; Carson, L; Carvalho Akiba, K; Casse, G; Cassina, L; Castillo Garcia, L; Cattaneo, M; Cavallero, G; Cenci, R; Chamont, D; Charles, M; Charpentier, Ph; Chatzikonstantinidis, G; Chefdeville, M; Chen, S; Cheung, S-F; Chobanova, V; Chrzaszcz, M; Cid Vidal, X; Ciezarek, G; Clarke, P E L; Clemencic, M; Cliff, H V; Closier, J; Coco, V; Cogan, J; Cogneras, E; Cogoni, V; Cojocariu, L; Collazuol, G; Collins, P; Comerma-Montells, A; Contu, A; Cook, A; Coombs, G; Coquereau, S; Corti, G; Corvo, M; Costa Sobral, C M; Couturier, B; Cowan, G A; Craik, D C; Crocombe, A; Cruz Torres, M; Cunliffe, S; Currie, R; D'Ambrosio, C; Da Cunha Marinho, F; Dall'Occo, E; Dalseno, J; David, P N Y; Davis, A; De Bruyn, K; De Capua, S; De Cian, M; De Miranda, J M; De Paula, L; De Serio, M; De Simone, P; Dean, C-T; Decamp, D; Deckenhoff, M; Del Buono, L; Demmer, M; Dendek, A; Derkach, D; Deschamps, O; Dettori, F; Dey, B; Di Canto, A; Dijkstra, H; Dordei, F; Dorigo, M; Dosil Suárez, A; Dovbnya, A; Dreimanis, K; Dufour, L; Dujany, G; Dungs, K; Durante, P; Dzhelyadin, R; Dziurda, A; Dzyuba, A; Déléage, N; Easo, S; Ebert, M; Egede, U; Egorychev, V; Eidelman, S; Eisenhardt, S; Eitschberger, U; Ekelhof, R; Eklund, L; Ely, S; Esen, S; Evans, H M; Evans, T; Falabella, A; Farley, N; Farry, S; Fay, R; Fazzini, D; Ferguson, D; Fernandez Prieto, A; Ferrari, F; Ferreira Rodrigues, F; Ferro-Luzzi, M; Filippov, S; Fini, R A; Fiore, M; Fiorini, M; Firlej, M; Fitzpatrick, C; Fiutowski, T; Fleuret, F; Fohl, K; Fontana, M; Fontanelli, F; Forshaw, D C; Forty, R; Franco Lima, V; Frank, M; Frei, C; Fu, J; Funk, W; Furfaro, E; Färber, C; Gallas Torreira, A; Galli, D; Gallorini, S; Gambetta, S; Gandelman, M; Gandini, P; Gao, Y; Garcia Martin, L M; García Pardiñas, J; Garra Tico, J; Garrido, L; Garsed, P J; Gascon, D; Gaspar, C; Gavardi, L; Gazzoni, G; Gerick, D; Gersabeck, E; Gersabeck, M; Gershon, T; Ghez, Ph; Gianì, S; Gibson, V; Girard, O G; Giubega, L; Gizdov, K; Gligorov, V V; Golubkov, D; Golutvin, A; Gomes, A; Gorelov, I V; Gotti, C; Graciani Diaz, R; Granado Cardoso, L A; Graugés, E; Graverini, E; Graziani, G; Grecu, A; Griffith, P; Grillo, L; Gruberg Cazon, B R; Grünberg, O; Gushchin, E; Guz, Yu; Gys, T; Göbel, C; Hadavizadeh, T; Hadjivasiliou, C; Haefeli, G; Haen, C; Haines, S C; Hall, S; Hamilton, B; Han, X; Hansmann-Menzemer, S; Harnew, N; Harnew, S T; Harrison, J; Hatch, M; He, J; Head, T; Heister, A; Hennessy, K; Henrard, P; Henry, L; van Herwijnen, E; Heß, M; Hicheur, A; Hill, D; Hombach, C; Hopchev, H; Hulsbergen, W; Humair, T; Hushchyn, M; Hutchcroft, D; Idzik, M; Ilten, P; Jacobsson, R; Jaeger, A; Jalocha, J; Jans, E; Jawahery, A; Jiang, F; John, M; Johnson, D; Jones, C R; Joram, C; Jost, B; Jurik, N; Kandybei, S; Karacson, M; Kariuki, J M; Karodia, S; Kecke, M; Kelsey, M; Kenzie, M; Ketel, T; Khairullin, E; Khanji, B; Khurewathanakul, C; Kirn, T; Klaver, S; Klimaszewski, K; Koliiev, S; Kolpin, M; Komarov, I; Koopman, R F; Koppenburg, P; Kosmyntseva, A; Kozachuk, A; Kozeiha, M; Kravchuk, L; Kreplin, K; Kreps, M; Krokovny, P; Kruse, F; Krzemien, W; Kucewicz, W; Kucharczyk, M; Kudryavtsev, V; Kuonen, A K; Kurek, K; Kvaratskheliya, T; Lacarrere, D; Lafferty, G; Lai, A; Lanfranchi, G; Langenbruch, C; Latham, T; Lazzeroni, C; Le Gac, R; van Leerdam, J; Leflat, A; Lefrançois, J; Lefèvre, R; Lemaitre, F; Lemos Cid, E; Leroy, O; Lesiak, T; Leverington, B; Li, T; Li, Y; Likhomanenko, T; Lindner, R; Linn, C; Lionetto, F; Liu, X; Loh, D; Longstaff, I; Lopes, J H; Lucchesi, D; Lucio Martinez, M; Luo, H; Lupato, A; Luppi, E; Lupton, O; Lusiani, A; Lyu, X; Machefert, F; Maciuc, F; Maev, O; Maguire, K; Malde, S; Malinin, A; Maltsev, T; Manca, G; Mancinelli, G; Manning, P; Maratas, J; Marchand, J F; Marconi, U; Marin Benito, C; Marinangeli, M; Marino, P; Marks, J; Martellotti, G; Martin, M; Martinelli, M; Martinez Santos, D; Martinez Vidal, F; Martins Tostes, D; Massacrier, L M; Massafferri, A; Matev, R; Mathad, A; Mathe, Z; Matteuzzi, C; Mauri, A; Maurice, E; Maurin, B; Mazurov, A; McCann, M; McNab, A; McNulty, R; Meadows, B; Meier, F; Meissner, M; Melnychuk, D; Merk, M; Merli, A; Michielin, E; Milanes, D A; Minard, M-N; Mitzel, D S; Mogini, A; Molina Rodriguez, J; Monroy, I A; Monteil, S; Morandin, M; Morawski, P; Mordà, A; Morello, M J; Morgunova, O; Moron, J; Morris, A B; Mountain, R; Muheim, F; Mulder, M; Mussini, M; Müller, D; Müller, J; Müller, K; Müller, V; Naik, P; Nakada, T; Nandakumar, R; Nandi, A; Nasteva, I; Needham, M; Neri, N; Neubert, S; Neufeld, N; Neuner, M; Nguyen, T D; Nguyen-Mau, C; Nieswand, S; Niet, R; Nikitin, N; Nikodem, T; Nogay, A; Novoselov, A; O'Hanlon, D P; Oblakowska-Mucha, A; Obraztsov, V; Ogilvy, S; Oldeman, R; Onderwater, C J G; Otalora Goicochea, J M; Otto, A; Owen, P; Oyanguren, A; Pais, P R; Palano, A; Palombo, F; Palutan, M; Papanestis, A; Pappagallo, M; Pappalardo, L L; Parker, W; Parkes, C; Passaleva, G; Pastore, A; Patel, G D; Patel, M; Patrignani, C; Pearce, A; Pellegrino, A; Penso, G; Pepe Altarelli, M; Perazzini, S; Perret, P; Pescatore, L; Petridis, K; Petrolini, A; Petrov, A; Petruzzo, M; Picatoste Olloqui, E; Pietrzyk, B; Pikies, M; Pinci, D; Pistone, A; Piucci, A; Placinta, V; Playfer, S; Plo Casasus, M; Poikela, T; Polci, F; Poluektov, A; Polyakov, I; Polycarpo, E; Pomery, G J; Popov, A; Popov, D; Popovici, B; Poslavskii, S; Potterat, C; Price, E; Price, J D; Prisciandaro, J; Pritchard, A; Prouve, C; Pugatch, V; Puig Navarro, A; Punzi, G; Qian, W; Quagliani, R; Rachwal, B; Rademacker, J H; Rama, M; Ramos Pernas, M; Rangel, M S; Raniuk, I; Ratnikov, F; Raven, G; Redi, F; Reichert, S; Dos Reis, A C; Remon Alepuz, C; Renaudin, V; Ricciardi, S; Richards, S; Rihl, M; Rinnert, K; Rives Molina, V; Robbe, P; Rodrigues, A B; Rodrigues, E; Rodriguez Lopez, J A; Rodriguez Perez, P; Rogozhnikov, A; Roiser, S; Rollings, A; Romanovskiy, V; Romero Vidal, A; Ronayne, J W; Rotondo, M; Rudolph, M S; Ruf, T; Ruiz Valls, P; Saborido Silva, J J; Sadykhov, E; Sagidova, N; Saitta, B; Salustino Guimaraes, V; Sanchez Mayordomo, C; Sanmartin Sedes, B; Santacesaria, R; Santamarina Rios, C; Santimaria, M; Santovetti, E; Sarti, A; Satriano, C; Satta, A; Saunders, D M; Savrina, D; Schael, S; Schellenberg, M; Schiller, M; Schindler, H; Schlupp, M; Schmelling, M; Schmelzer, T; Schmidt, B; Schneider, O; Schopper, A; Schubert, K; Schubiger, M; Schune, M-H; Schwemmer, R; Sciascia, B; Sciubba, A; Semennikov, A; Sergi, A; Serra, N; Serrano, J; Sestini, L; Seyfert, P; Shapkin, M; Shapoval, I; Shcheglov, Y; Shears, T; Shekhtman, L; Shevchenko, V; Siddi, B G; Silva Coutinho, R; Silva de Oliveira, L; Simi, G; Simone, S; Sirendi, M; Skidmore, N; Skwarnicki, T; Smith, E; Smith, I T; Smith, J; Smith, M; Snoek, H; Soares Lavra, L; Sokoloff, M D; Soler, F J P; Souza De Paula, B; Spaan, B; Spradlin, P; Sridharan, S; Stagni, F; Stahl, M; Stahl, S; Stefko, P; Stefkova, S; Steinkamp, O; Stemmle, S; Stenyakin, O; Stevens, H; Stevenson, S; Stoica, S; Stone, S; Storaci, B; Stracka, S; Straticiuc, M; Straumann, U; Sun, L; Sutcliffe, W; Swientek, K; Syropoulos, V; Szczekowski, M; Szumlak, T; T'Jampens, S; Tayduganov, A; Tekampe, T; Tellarini, G; Teubert, F; Thomas, E; van Tilburg, J; Tilley, M J; Tisserand, V; Tobin, M; Tolk, S; Tomassetti, L; Tonelli, D; Topp-Joergensen, S; Toriello, F; Tournefier, E; Tourneur, S; Trabelsi, K; Traill, M; Tran, M T; Tresch, M; Trisovic, A; Tsaregorodtsev, A; Tsopelas, P; Tully, A; Tuning, N; Ukleja, A; Ustyuzhanin, A; Uwer, U; Vacca, C; Vagnoni, V; Valassi, A; Valat, S; Valenti, G; Vazquez Gomez, R; Vazquez Regueiro, P; Vecchi, S; van Veghel, M; Velthuis, J J; Veltri, M; Veneziano, G; Venkateswaran, A; Vernet, M; Vesterinen, M; Viana Barbosa, J V; Viaud, B; Vieira, D; Vieites Diaz, M; Viemann, H; Vilasis-Cardona, X; Vitti, M; Volkov, V; Vollhardt, A; Voneki, B; Vorobyev, A; Vorobyev, V; Voß, C; de Vries, J A; Vázquez Sierra, C; Waldi, R; Wallace, C; Wallace, R; Walsh, J; Wang, J; Ward, D R; Wark, H M; Watson, N K; Websdale, D; Weiden, A; Whitehead, M; Wicht, J; Wilkinson, G; Wilkinson, M; Williams, M; Williams, M P; Williams, M; Williams, T; Wilson, F F; Wimberley, J; Wishahi, J; Wislicki, W; Witek, M; Wormser, G; Wotton, S A; Wraight, K; Wyllie, K; Xie, Y; Xing, Z; Xu, Z; Yang, Z; Yao, Y; Yin, H; Yu, J; Yuan, X; Yushchenko, O; Zarebski, K A; Zavertyaev, M; Zhang, L; Zhang, Y; Zhang, Y; Zhelezov, A; Zheng, Y; Zhu, X; Zhukov, V; Zucchelli, S

2017-01-01

A measurement of the phase difference between the short- and long-distance contributions to the [Formula: see text] decay is performed by analysing the dimuon mass distribution. The analysis is based on pp collision data corresponding to an integrated luminosity of 3[Formula: see text] collected by the LHCb experiment in 2011 and 2012. The long-distance contribution to the [Formula: see text] decay is modelled as a sum of relativistic Breit-Wigner amplitudes representing different vector meson resonances decaying to muon pairs, each with their own magnitude and phase. The measured phases of the [Formula: see text] and [Formula: see text] resonances are such that the interference with the short-distance component in dimuon mass regions far from their pole masses is small. In addition, constraints are placed on the Wilson coefficients, [Formula: see text] and [Formula: see text], and the branching fraction of the short-distance component is measured.

Revisitation of FRET methods to measure intraprotein distances in Human Serum Albumin

Energy Technology Data Exchange (ETDEWEB)

Santini, S.; Bizzarri, A.R.; Cannistraro, S., E-mail: cannistr@unitus.it

2016-11-15

We revisited the FRET methods to measure the intraprotein distance between Trp-214 (used as donor) of Human Serum Albumin and its Cys-34, labelled with 1.5-Iaedans (used as acceptor). Variation of Trp fluorescence emission in terms of both intensity and lifetime, as well the enhancement of the acceptor fluorescence emission upon Trp excitation, have been monitored. A careful statistical analysis of the fluorescence results from ten independently prepared samples, combined with suitable spectral corrections, provided reproducible distances estimations by each one of the three methods. Even if monitoring of the donor lifetime variation in the presence of the acceptor reproduces at the best the crystallographic data, by allowing even sub-nanometre distance variations to be appreciated, we suggest that a comparative analysis of all the three methods, applied with statistical significance, should be preferred to achieve a better reliability of the FRET technique.

Comparative Study of Nei�s D with other Genetic Distance Measures between Barak Valley Muslims and other Nations for ABO Locus

Directory of Open Access Journals (Sweden)

Supriyo CHAKRABORTY

2012-02-01

Full Text Available Quantification of the genetic distance between populations is essential in many genetic research programs. Several formulae were proposed for the estimation of genetic distance between populations using gene frequency data. But the selection of a suitable measure for estimating genetic distance between real-world human populations is a very difficult task despite the widely used measure Neis D. The present study was undertaken to estimate the genetic distance between Barak Valley Muslims (BVM and other twenty-four nations using seven different measures with ABO blood group gene frequency data for comparative analysis and to estimate the correlation coefficients between distance measures and to work out the linear regression equations. Seven genetic distance measures namely Neis D, Neis Nm, La, Neis Da, Dc, Re and Neis Ne were estimated between BVM and other 24 nations enroute the journey of mankind from Africa that commenced about 200,000 years ago (www.bradshawfoundation.com. Correlation coefficients between Neis D with other measures were estimated to find out which other genetic distance measures were closely related to Neis D. Neis D showed highly significant (p=0.01 positive correlation with Cavalli-Sforza and Edwards chord distance Dc (0.90, Reynolds Re (0.90, Neis Da (0.74 and Neis Ne (0.63 but negative correlation with Neis Nm and La. Linear regression equations of Neis D with other distance measures were estimated as Da = -0.80 + 1.34D, Dc = 1.91 + 4.44D, Re = -0.51 + 0.24D and Ne = -7.60 + 1.30D.

Comparison of Travel-Time and Amplitude Measurements for Deep-Focusing Time-Distance Helioseismology

Science.gov (United States)

Pourabdian, Majid; Fournier, Damien; Gizon, Laurent

2018-04-01

The purpose of deep-focusing time-distance helioseismology is to construct seismic measurements that have a high sensitivity to the physical conditions at a desired target point in the solar interior. With this technique, pairs of points on the solar surface are chosen such that acoustic ray paths intersect at this target (focus) point. Considering acoustic waves in a homogeneous medium, we compare travel-time and amplitude measurements extracted from the deep-focusing cross-covariance functions. Using a single-scattering approximation, we find that the spatial sensitivity of deep-focusing travel times to sound-speed perturbations is zero at the target location and maximum in a surrounding shell. This is unlike the deep-focusing amplitude measurements, which have maximum sensitivity at the target point. We compare the signal-to-noise ratio for travel-time and amplitude measurements for different types of sound-speed perturbations, under the assumption that noise is solely due to the random excitation of the waves. We find that, for highly localized perturbations in sound speed, the signal-to-noise ratio is higher for amplitude measurements than for travel-time measurements. We conclude that amplitude measurements are a useful complement to travel-time measurements in time-distance helioseismology.

Brownian distance covariance

OpenAIRE

Székely, Gábor J.; Rizzo, Maria L.

2010-01-01

Distance correlation is a new class of multivariate dependence coefficients applicable to random vectors of arbitrary and not necessarily equal dimension. Distance covariance and distance correlation are analogous to product-moment covariance and correlation, but generalize and extend these classical bivariate measures of dependence. Distance correlation characterizes independence: it is zero if and only if the random vectors are independent. The notion of covariance with...

Polymer deposition morphology by electrospray deposition - Modifications through distance variation

International Nuclear Information System (INIS)

Altmann, K.; Schulze, R.-D.; Friedrich, J.

2014-01-01

Electrospray deposition (ESD) of highly diluted polymers was examined with regard to the deposited surface structure. Only the flight distance (flight time) onto the resulting deposited surface was varied from 20 to 200 mm. An apparatus without any additional heating or gas flows was used. Polyacrylic acid (PAA) and polyallylamine (PAAm) in methanol were deposited on Si wafers. The polymer layers were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, derivatization reactions and Fourier transform infrared spectroscopy using a grazing incidence unit. SEM images illustrated the changing structures of PAA and PAAm. For PAA the deposited structure changed from a smooth film (20 mm) to a film with individual droplets on the coated surface (100 mm and 200 mm), while for PAAm individual droplets can be seen at all distances. The ESD process with cascades of splitting droplets slows down for PAA after distances greater than 40 mm. In contrast, the ESD process for PAAm is nearly stopped within the first flight distance of 20 mm. Residual solvent analysis showed that most of the solvent evaporated within the first 20 mm capillary-sample distance. - Highlights: • We deposited polyacrylic acid and polyallylamine by electrospray ionization (ESI). • The morphology in dependence of flight distance (20 mm to 200 mm) was analyzed. • The amount of residual solvent after deposition was determined. • ESI-process slows down for polyacrylic acid after 40 mm flight distance. • ESI-Process is complete for polyallylamine within the first 20 mm

RFDR with Adiabatic Inversion Pulses: Application to Internuclear Distance Measurements

International Nuclear Information System (INIS)

Leppert, Joerg; Ohlenschlaeger, Oliver; Goerlach, Matthias; Ramachandran, Ramadurai

2004-01-01

In the context of the structural characterisation of biomolecular systems via MAS solid state NMR, the potential utility of homonuclear dipolar recoupling with adiabatic inversion pulses has been assessed via numerical simulations and experimental measurements. The results obtained suggest that it is possible to obtain reliable estimates of internuclear distances via an analysis of the initial cross-peak intensity buildup curves generated from two-dimensional adiabatic inversion pulse driven longitudinal magnetisation exchange experiments

Experimental study on performance verification tests for coordinate measuring systems with optical distance sensors

Science.gov (United States)

Carmignato, Simone

2009-01-01

Optical sensors are increasingly used for dimensional and geometrical metrology. However, the lack of international standards for testing optical coordinate measuring systems is currently limiting the traceability of measurements and the easy comparison of different optical systems. This paper presents an experimental investigation on artefacts and procedures for testing coordinate measuring systems equipped with optical distance sensors. The work is aimed at contributing to the standardization of testing methods. The VDI/VDE 2617-6.2:2005 guideline, which is probably the most complete document available at the state of the art for testing systems with optical distance sensors, is examined with specific experiments. Results from the experiments are discussed, with particular reference to the tests used for determining the following characteristics: error of indication for size measurement, probing error and structural resolution. Particular attention is given to the use of artefacts alternative to gauge blocks for determining the error of indication for size measurement.

Functional claudication distance: a reliable and valid measurement to assess functional limitation in patients with intermittent claudication

Directory of Open Access Journals (Sweden)

Prins Martin H

2009-03-01

Full Text Available Abstract Background Disease severity and functional impairment in patients with intermittent claudication is usually quantified by the measurement of pain-free walking distance (intermittent claudication distance, ICD and maximal walking distance (absolute claudication distance, ACD. However, the distance at which a patient would prefer to stop because of claudication pain seems a definition that is more correspondent with the actual daily life walking distance. We conducted a study in which the distance a patient prefers to stop was defined as the functional claudication distance (FCD, and estimated the reliability and validity of this measurement. Methods In this clinical validity study we included patients with intermittent claudication, following a supervised exercise therapy program. The first study part consisted of two standardised treadmill tests. During each test ICD, FCD and ACD were determined. Primary endpoint was the reliability as represented by the calculated intra-class correlation coefficients. In the second study part patients performed a standardised treadmill test and filled out the Rand-36 questionnaire. Spearman's rho was calculated to assess validity. Results The intra-class correlation coefficients of ICD, FCD and ACD were 0.940, 0.959, and 0.975 respectively. FCD correlated significantly with five out of nine domains, namely physical function (rho = 0.571, physical role (rho = 0.532, vitality (rho = 0.416, pain (rho = 0.416 and health change (rho = 0.414. Conclusion FCD is a reliable and valid measurement for determining functional capacity in trained patients with intermittent claudication. Furthermore it seems that FCD better reflects the actual functional impairment. In future studies, FCD could be used alongside ICD and ACD.

Multiwavelength Raman-fiber-laser-based long-distance remote sensor for simultaneous measurement of strain and temperature.

Science.gov (United States)

Han, Young-Geun; Tran, T V A; Kim, Sang-Hyuck; Lee, Sang Bae

2005-06-01

We propose a simple and flexible multiwavelength Raman-fiber-laser-based long-distance remote-sensing scheme for simultaneous measurement of strain and temperature by use of fiber Bragg gratings. By combining two uniform fiber Bragg gratings with a tunable chirped fiber grating, we readily achieve simultaneous two-channel sensing probes with a high extinction ratio of more than approximately 50 dB over a 50-km distance. When strain and temperature are applied, lasing wavelength separation and shift occur, respectively, since the two uniform fiber Bragg gratings have identical material composition and different cladding diameters. This allows simultaneous measurement of strain and temperature for long-distance sensing applications of more than 50 km.

Measurement of distances between anatomical structures using a translating stage with mounted endoscope

Science.gov (United States)

Kahrs, Lueder A.; Blachon, Gregoire S.; Balachandran, Ramya; Fitzpatrick, J. Michael; Labadie, Robert F.

2012-02-01

During endoscopic procedures it is often desirable to determine the distance between anatomical features. One such clinical application is percutaneous cochlear implantation (PCI), which is a minimally invasive approach to the cochlea via a single, straight drill path and can be achieved accurately using bone-implanted markers and customized microstereotactic frame. During clinical studies to validate PCI, traditional open-field cochlear implant surgery was performed and prior to completion of the surgery, a customized microstereotactic frame designed to achieve the desired PCI trajectory was attached to the bone-implanted markers. To determine whether this trajectory would have safely achieved the target, a sham drill bit is passed through the frame to ensure that the drill bit would reach the cochlea without damaging vital structures. Because of limited access within the facial recess, the distances from the bit to anatomical features could not be measured with calipers. We hypothesized that an endoscope mounted on a sliding stage that translates only along the trajectory, would provide sufficient triangulation to accurately measure these distances. In this paper, the design, fabrication, and testing of such a system is described. The endoscope is mounted so that its optical axis is approximately aligned with the trajectory. Several images are acquired as the stage is moved, and threedimensional reconstruction of selected points allows determination of distances. This concept also has applicability in a large variety of rigid endoscopic interventions including bronchoscopy, laparoscopy, and sinus endoscopy.

Optimization methods of pulse-to-pulse alignment using femtosecond pulse laser based on temporal coherence function for practical distance measurement

Science.gov (United States)

Liu, Yang; Yang, Linghui; Guo, Yin; Lin, Jiarui; Cui, Pengfei; Zhu, Jigui

2018-02-01

An interferometer technique based on temporal coherence function of femtosecond pulses is demonstrated for practical distance measurement. Here, the pulse-to-pulse alignment is analyzed for large delay distance measurement. Firstly, a temporal coherence function model between two femtosecond pulses is developed in the time domain for the dispersive unbalanced Michelson interferometer. Then, according to this model, the fringes analysis and the envelope extraction process are discussed. Meanwhile, optimization methods of pulse-to-pulse alignment for practical long distance measurement are presented. The order of the curve fitting and the selection of points for envelope extraction are analyzed. Furthermore, an averaging method based on the symmetry of the coherence function is demonstrated. Finally, the performance of the proposed methods is evaluated in the absolute distance measurement of 20 μ m with path length difference of 9 m. The improvement of standard deviation in experimental results shows that these approaches have the potential for practical distance measurement.

Radioactive means for measuring distance intervals between anomalies in an earth formation

International Nuclear Information System (INIS)

Sandier, G.; Nels, J.P.

1975-01-01

In earth formation measurements an investigating tool having a first and a second detector at a relatively small spacing from each other and a third detector at a relatively great spacing from the first and second detectors is moved through a borehole having anomalies such as radioactive bullets or casing joints which are relatively uniformly spaced from each other by a distance which is of the order of said great spacing between the third detector and the first and the second detectors. The first and second detectors generate detection signal peaks for the same anomaly within a short time interval, and the third detector generates a detection signal peak for an adjacent anomaly at about the same time. By means of a defined apparatus, electrical signals representing the times of occurrence of the detection signal peaks from the first and second detectors for the same anomaly and the known small spacing between these detectors are used to obtain an electrical signal for the speed of the investigating tool at that time, and at least some of these electrical signals are combined with electrical signals representing the time of occurrence of the detection signal peak from the third detector for an adjacent anomaly and at least one of the known distances between the detectors to thereby obtain an accurate measure of the distance interval between the pair of adjacent anomalies. (U.S.)

Encyclopedia of distances

CERN Document Server

Deza, Michel Marie

2016-01-01

This 4th edition of the leading reference volume on distance metrics is characterized by updated and rewritten sections on some items suggested by experts and readers, as well a general streamlining of content and the addition of essential new topics. Though the structure remains unchanged, the new edition also explores recent advances in the use of distances and metrics for e.g. generalized distances, probability theory, graph theory, coding theory, data analysis. New topics in the purely mathematical sections include e.g. the Vitanyi multiset-metric, algebraic point-conic distance, triangular ratio metric, Rossi-Hamming metric, Taneja distance, spectral semimetric between graphs, channel metrization, and Maryland bridge distance. The multidisciplinary sections have also been supplemented with new topics, including: dynamic time wrapping distance, memory distance, allometry, atmospheric depth, elliptic orbit distance, VLBI distance measurements, the astronomical system of units, and walkability distance. Lea...

In-beam gamma spectroscopy of /sup 82/Sr

CERN Document Server

Dewald, A; Gelberg, A; Kaup, U; Von Brentano, P; Zell, K O

1981-01-01

The excited levels of /sup 82/Sr have been investigated by means of in-beam gamma-ray spectroscopy via the reactions /sup 72/Ge(/sup 12/C, 2n), /sup 66/Zn(/sup 19/F, p2n), and /sup 79/Br(/sup 6/Li, 3n). Lifetimes of excited states were measured by the recoil distance method. Excitation energies and B(E2) values have been compared with calculations using the Interacting Boson Model. (19 refs).

Dynamic cerebral autoregulation measured with coherent hemodynamics spectroscopy (CHS)

Science.gov (United States)

Kainerstorfer, Jana M.; Sassaroli, Angelo; Tgavalekos, Kristen T.; Fantini, Sergio

2015-03-01

Coherent Hemodynamics Spectroscopy (CHS) is a novel technique for non-invasive measurements of local microcirculation quantities such as the capillary blood transit times and dynamic autoregulation. The basis of CHS is to measure, for instance with near-infrared spectroscopy (NIRS), peripheral coherent hemodynamic changes that are induced by controlled perturbations in the systemic mean arterial pressure (MAP). In this study, the MAP perturbation was induced by the fast release of two pneumatic cuffs placed around the subject's thighs after they were kept inflated (at 200 mmHg) for two minutes. The resulting transient changes in cerebral oxy- (O) and deoxy- (D) hemoglobin concentrations measured with NIRS on the prefrontal cortex are then described by a novel hemodynamic model, from which quantifiable parameters such as the capillary blood transit time and a cutoff frequency for cerebral autoregulation are obtained. We present results on eleven healthy volunteers in a protocol involving measurements during normal breathing and during hyperventilation, which is known to cause a hypocapnia-induced increase in cerebral autoregulation. The measured capillary transit time was unaffected by hyperventilation (normal breathing: 1.1±0.1 s; hyperventilation: 1.1±0.1 s), whereas the cutoff frequency of autoregulation, which increases for higher autoregulation efficiency, was indeed found to be significantly greater during hyperventilation (normal breathing: 0.017±0.002 Hz; hyperventilation: 0.034±0.005 Hz). These results provide a validation of local cerebral autoregulation measurements with the new technique of CHS.

THE DISTANCE TO M51

Energy Technology Data Exchange (ETDEWEB)

McQuinn, Kristen B. W. [University of Texas at Austin, McDonald Observatory, 2515 Speedway, Stop C1400 Austin, TX 78712 (United States); Skillman, Evan D. [Minnesota Institute for Astrophysics, School of Physics and Astronomy, 116 Church Street, S.E., University of Minnesota, Minneapolis, MN 55455 (United States); Dolphin, Andrew E. [Raytheon Company, 1151 E. Hermans Road, Tucson, AZ 85756 (United States); Berg, Danielle [Center for Gravitation, Cosmology and Astrophysics, Department of Physics, University of Wisconsin Milwaukee, 1900 East Kenwood Boulevard, Milwaukee, WI 53211 (United States); Kennicutt, Robert, E-mail: kmcquinn@astro.as.utexas.edu [Institute for Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)

2016-07-20

Great investments of observing time have been dedicated to the study of nearby spiral galaxies with diverse goals ranging from understanding the star formation process to characterizing their dark matter distributions. Accurate distances are fundamental to interpreting observations of these galaxies, yet many of the best studied nearby galaxies have distances based on methods with relatively large uncertainties. We have started a program to derive accurate distances to these galaxies. Here we measure the distance to M51—the Whirlpool galaxy—from newly obtained Hubble Space Telescope optical imaging using the tip of the red giant branch method. We measure the distance modulus to be 8.58 ± 0.10 Mpc (statistical), corresponding to a distance modulus of 29.67 ± 0.02 mag. Our distance is an improvement over previous results as we use a well-calibrated, stable distance indicator, precision photometry in a optimally selected field of view, and a Bayesian Maximum Likelihood technique that reduces measurement uncertainties.

Absolute distance measurement by dual-comb interferometry with multi-channel digital lock-in phase detection

International Nuclear Information System (INIS)

Yang, Ruitao; Pollinger, Florian; Meiners-Hagen, Karl; Krystek, Michael; Bosse, Harald; Tan, Jiubin

2015-01-01

We present a dual-comb-based heterodyne multi-wavelength absolute interferometer capable of long distance measurements. The phase information of the various comb modes is extracted in parallel by a multi-channel digital lock-in phase detection scheme. Several synthetic wavelengths of the same order are constructed and the corresponding phases are averaged to deduce the absolute lengths with significantly reduced uncertainty. Comparison experiments with an incremental HeNe reference interferometer show a combined relative measurement uncertainty of 5.3 × 10 −7 at a measurement distance of 20 m. Combining the advantage of synthetic wavelength interferometry and dual-comb interferometry, our compact and simple approach provides sufficient precision for many industrial applications. (paper)

Absolute distance measurement by dual-comb interferometry with multi-channel digital lock-in phase detection

Science.gov (United States)

Yang, Ruitao; Pollinger, Florian; Meiners-Hagen, Karl; Krystek, Michael; Tan, Jiubin; Bosse, Harald

2015-08-01

We present a dual-comb-based heterodyne multi-wavelength absolute interferometer capable of long distance measurements. The phase information of the various comb modes is extracted in parallel by a multi-channel digital lock-in phase detection scheme. Several synthetic wavelengths of the same order are constructed and the corresponding phases are averaged to deduce the absolute lengths with significantly reduced uncertainty. Comparison experiments with an incremental HeNe reference interferometer show a combined relative measurement uncertainty of 5.3 × 10-7 at a measurement distance of 20 m. Combining the advantage of synthetic wavelength interferometry and dual-comb interferometry, our compact and simple approach provides sufficient precision for many industrial applications.

Motor fatigue measurement by distance-induced slow down of walking speed in multiple sclerosis.

Directory of Open Access Journals (Sweden)

Rémy Phan-Ba

Full Text Available BACKGROUND AND RATIONALE: Motor fatigue and ambulation impairment are prominent clinical features of people with multiple sclerosis (pMS. We hypothesized that a multimodal and comparative assessment of walking speed on short and long distance would allow a better delineation and quantification of gait fatigability in pMS. Our objectives were to compare 4 walking paradigms: the timed 25-foot walk (T25FW, a corrected version of the T25FW with dynamic start (T25FW(+, the timed 100-meter walk (T100MW and the timed 500-meter walk (T500MW. METHODS: Thirty controls and 81 pMS performed the 4 walking tests in a single study visit. RESULTS: The 4 walking tests were performed with a slower WS in pMS compared to controls even in subgroups with minimal disability. The finishing speed of the last 100-meter of the T500MW was the slowest measurable WS whereas the T25FW(+ provided the fastest measurable WS. The ratio between such slowest and fastest WS (Deceleration Index, DI was significantly lower only in pMS with EDSS 4.0-6.0, a pyramidal or cerebellar functional system score reaching 3 or a maximum reported walking distance ≤ 4000 m. CONCLUSION: The motor fatigue which triggers gait deceleration over a sustained effort in pMS can be measured by the WS ratio between performances on a very short distance and the finishing pace on a longer more demanding task. The absolute walking speed is abnormal early in MS whatever the distance of effort when patients are unaware of ambulation impairment. In contrast, the DI-measured ambulation fatigability appears to take place later in the disease course.

Displacement, distance, and shape measurements of fast-rotating rough objects by two mutually tilted interference fringe systems.

Science.gov (United States)

Günther, Philipp; Kuschmierz, Robert; Pfister, Thorsten; Czarske, Jürgen W

2013-05-01

The precise distance measurement of fast-moving rough surfaces is important in several applications such as lathe monitoring. A nonincremental interferometer based on two mutually tilted interference fringe systems has been realized for this task. The distance is coded in the phase difference between the generated interference signals corresponding to the fringe systems. Large tilting angles between the interference fringe systems are necessary for a high sensitivity. However, due to the speckle effect at rough surfaces, different envelopes and phase jumps of the interference signals occur. At large tilting angles, these signals become dissimilar, resulting in a small correlation coefficient and a high measurement uncertainty. Based on a matching of illumination and receiving optics, the correlation coefficient and the phase difference estimation have been improved significantly. For axial displacement measurements of recurring rough surfaces, laterally moving with velocities of 5 m/s, an uncertainty of 110 nm has been attained. For nonrecurring surfaces, a distance measurement uncertainty of 830 nm has been achieved. Incorporating the additionally measured lateral velocity and the rotational speed, the two-dimensional shape of rotating objects results. Since the measurement uncertainty of the displacement, distance, and shape is nearly independent of the lateral surface velocity, this technique is predestined for fast-rotating objects, such as crankshafts, camshafts, vacuum pump shafts, or turning parts of lathes.

Improved GPS-based Satellite Relative Navigation Using Femtosecond Laser Relative Distance Measurements

Directory of Open Access Journals (Sweden)

Hyungjik Oh

2016-03-01

Full Text Available This study developed an approach for improving Carrier-phase Differential Global Positioning System (CDGPS based realtime satellite relative navigation by applying laser baseline measurement data. The robustness against the space operational environment was considered, and a Synthetic Wavelength Interferometer (SWI algorithm based on a femtosecond laser measurement model was developed. The phase differences between two laser wavelengths were combined to measure precise distance. Generated laser data were used to improve estimation accuracy for the float ambiguity of CDGPS data. Relative navigation simulations in real-time were performed using the extended Kalman filter algorithm. The GPS and laser-combined relative navigation accuracy was compared with GPS-only relative navigation solutions to determine the impact of laser data on relative navigation. In numerical simulations, the success rate of integer ambiguity resolution increased when laser data was added to GPS data. The relative navigational errors also improved five-fold and two-fold, relative to the GPS-only error, for 250 m and 5 km initial relative distances, respectively. The methodology developed in this study is suitable for application to future satellite formation-flying missions.

Mass measurement of 80Y by β-γ coincidence spectroscopy

International Nuclear Information System (INIS)

Barton, C.J.; Caprio, M.A.; Beausang, C.W.; Casten, R.F.; Cooper, J.R.; Kruecken, R.; Novak, J.R.; Pietralla, N.; Brenner, D.S.; Zamfir, N.V.; Aprahamian, A.; Wiescher, M.C.; Shawcross, M.; Teymurazyan, A.; Berant, Z.; Wolf, A.; Gill, R.L.

2003-01-01

The Q EC value of 80 Y has been measured by β-γ coincidence spectroscopy to be ≥8929(83) keV. Combining this result with the adopted mass excess of the daughter 80 Sr gives a mass excess for 80 Y of ≥-61 376(83) keV. Results are compared with other measurements, with Audi-Wapstra systematics, and with predictions of mass formulas. Implications of this measurement are considered for the rp process

First-Year Spectroscopy for the SDSS-II Supernova Survey

Energy Technology Data Exchange (ETDEWEB)

Zheng, Chen; Romani, Roger W.; Sako, Masao; Marriner, John; Bassett, Bruce; Becker, Andrew; Choi, Changsu; Cinabro, David; DeJongh, Fritz; Depoy, Darren L.; Dilday, Ben; Doi, Mamoru; Frieman, Joshua A.; Garnavich, Peter M.; Hogan, Craig J.; Holtzman, Jon; Im, Myungshin; Jha, Saurabh; Kessler, Richard; Konishi, Kohki; Lampeitl, Hubert

2008-03-25

This paper presents spectroscopy of supernovae discovered in the first season of the Sloan Digital Sky Survey-II Supernova Survey. This program searches for and measures multi-band light curves of supernovae in the redshift range z = 0.05-0.4, complementing existing surveys at lower and higher redshifts. Our goal is to better characterize the supernova population, with a particular focus on SNe Ia, improving their utility as cosmological distance indicators and as probes of dark energy. Our supernova spectroscopy program features rapid-response observations using telescopes of a range of apertures, and provides confirmation of the supernova and host-galaxy types as well as precise redshifts. We describe here the target identification and prioritization, data reduction, redshift measurement, and classification of 129 SNe Ia, 16 spectroscopically probable SNe Ia, 7 SNe Ib/c, and 11 SNe II from the first season. We also describe our efforts to measure and remove the substantial host galaxy contamination existing in the majority of our SN spectra.

Automatic setting of the distance between sample and detector in gamma-ray spectroscopy

International Nuclear Information System (INIS)

Andeweg, A.H.

1980-01-01

An apparatus has been developed that automatically sets the distance from the sample to the detector according to the radioactivity of the sample. The distance-setting unit works in conjuction with an automatic sample changer, and is interconnected with other components so that the counting head automatically moves to the optimum distance for the analysis of a particular sample. The distance, which is indicated digitally in increments of 0,01 mm, can be set between 18 and 995 mm at count rates that can be preset between 1000 and 10 000 counts per second. On being tested, the instrument performed well within the desired range and accuracy. Under routine conditions, the spectra were much more accurate than before, especially when samples of different radioactivity were counted

Synchrotron radiation based Mössbauer absorption spectroscopy of various nuclides

Energy Technology Data Exchange (ETDEWEB)

Masuda, Ryo, E-mail: masudar@rri.kyoto-u.ac.jp; Kobayashi, Yasuhiro; Kitao, Shinji; Kurokuzu, Masayuki; Saito, Makina [Kyoto University, Research Reactor Institute (Japan); Yoda, Yoshitaka [Japan Synchrotron Radiation Research Institute, Resarch and Utilization Division (Japan); Mitsui, Takaya [Japan Atomic Energy Agency, Condensed Matter Science Division, Sector of Nuclear Science Research (Japan); Seto, Makoto [Kyoto University, Research Reactor Institute (Japan)

2016-12-15

Synchrotron-radiation (SR) based Mössbauer absorption spectroscopy of various nuclides is reviewed. The details of the measuring system and analysis method are described. Especially, the following two advantages of the current system are described: the detection of internal conversion electrons and the close distance between the energy standard scatterer and the detector. Both of these advantages yield the enhancement of the counting rate and reduction of the measuring time. Furthermore, SR-based Mössbauer absorption spectroscopy of {sup 40}K, {sup 151}Eu, and {sup 174}Yb is introduced to show the wide applicability of this method. In addition to these three nuclides, SR-based Mössbauer absorption spectroscopy of {sup 61}Ni, {sup 73}Ge, {sup 119}Sn, {sup 125}Te, {sup 127}I, {sup 149}Sm, and {sup 189}Os has been performed. We continue to develop the method to increase available nuclides and to increase its ease of use. The complementary relation between the time-domain method using SR, such as nuclear forward scattering and the energy-domain methods such as SR-based Mössbauer absorption spectroscopy is also noted.

Note: Optical and electronic design of an amplitude-modulated continuous-wave laser scanner for high-accuracy distance measurement

Energy Technology Data Exchange (ETDEWEB)

Jang, Junhwan; Hwang, Sungui; Park, Kyihwan, E-mail: khpark@gist.ac.kr [School of Mechatronics, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju (Korea, Republic of)

2015-04-15

To utilize a time-of-flight-based laser scanner as a distance measurement sensor, the measurable distance and accuracy are the most important performance parameters to consider. For these purposes, the optical system and electronic signal processing of the laser scanner should be optimally designed in order to reduce a distance error caused by the optical crosstalk and wide dynamic range input. Optical system design for removing optical crosstalk problem is proposed in this work. Intensity control is also considered to solve the problem of a phase-shift variation in the signal processing circuit caused by object reflectivity. The experimental results for optical system and signal processing design are performed using 3D measurements.

Note: Optical and electronic design of an amplitude-modulated continuous-wave laser scanner for high-accuracy distance measurement

International Nuclear Information System (INIS)

Jang, Junhwan; Hwang, Sungui; Park, Kyihwan

2015-01-01

To utilize a time-of-flight-based laser scanner as a distance measurement sensor, the measurable distance and accuracy are the most important performance parameters to consider. For these purposes, the optical system and electronic signal processing of the laser scanner should be optimally designed in order to reduce a distance error caused by the optical crosstalk and wide dynamic range input. Optical system design for removing optical crosstalk problem is proposed in this work. Intensity control is also considered to solve the problem of a phase-shift variation in the signal processing circuit caused by object reflectivity. The experimental results for optical system and signal processing design are performed using 3D measurements

Characterization of atmospheric aerosols in the Adirondack Mountains using PIXE, SEM/EDX, and Micro-Raman spectroscopies

Energy Technology Data Exchange (ETDEWEB)

Vineyard, M.F., E-mail: vineyarm@union.edu; LaBrake, S.M.; Ali, S.F.; Nadareski, B.J.; Safiq, A.D.; Smith, J.W.; Yoskowitz, J.T.

2015-05-01

We are making detailed measurements of the composition of atmospheric aerosols collected in the Adirondack Mountains as a function of particle size using proton-induced X-ray emission, scanning electron microscopy with energy-dispersive X-ray spectroscopy, and Micro-Raman spectroscopy. These measurements provide valuable data to help identify the sources and understand the transport, transformation, and effects of airborne pollutants in upstate New York. Preliminary results indicate significant concentrations of sulfur in small particles that can travel great distances, and that this sulfur may be in the form of oxides that can contribute to acid rain.

THE DISTANCE TO M104

Energy Technology Data Exchange (ETDEWEB)

McQuinn, Kristen B. W. [University of Texas at Austin, McDonald Observatory, 2515 Speedway, Stop C1400 Austin, TX 78712 (United States); Skillman, Evan D. [Minnesota Institute for Astrophysics, School of Physics and Astronomy, 116 Church Street, SE, University of Minnesota, Minneapolis, MN 55455 (United States); Dolphin, Andrew E. [Raytheon Company, 1151 E. Hermans Road, Tucson, AZ 85756 (United States); Berg, Danielle [Center for Gravitation, Cosmology and Astrophysics, Department of Physics, University of Wisconsin Milwaukee, 1900 East Kenwood Boulevard, Milwaukee, WI 53211 (United States); Kennicutt, Robert, E-mail: kmcquinn@astro.as.utexas.edu [Institute for Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)

2016-11-01

M104 (NGC 4594; the Sombrero galaxy) is a nearby, well-studied elliptical galaxy included in scores of surveys focused on understanding the details of galaxy evolution. Despite the importance of observations of M104, a consensus distance has not yet been established. Here, we use newly obtained Hubble Space Telescope optical imaging to measure the distance to M104 based on the tip of the red giant branch (TRGB) method. Our measurement yields the distance to M104 to be 9.55 ± 0.13 ± 0.31 Mpc equivalent to a distance modulus of 29.90 ± 0.03 ± 0.07 mag. Our distance is an improvement over previous results as we use a well-calibrated, stable distance indicator, precision photometry in a optimally selected field of view, and a Bayesian maximum likelihood technique that reduces measurement uncertainties. The most discrepant previous results are due to Tully–Fisher method distances, which are likely inappropriate for M104 given its peculiar morphology and structure. Our results are part of a larger program to measure accurate distances to a sample of well-known spiral galaxies (including M51, M74, and M63) using the TRGB method.

Quantitative mixture fraction measurements in combustion system via laser induced breakdown spectroscopy

KAUST Repository

Mansour, Mohy S.; Imam, Hisham; Elsayed, Khaled A.; Elbaz, Ayman M.; Abbass, Wafaa

2015-01-01

Laser induced breakdown spectroscopy (LIBS) technique has been applied to quantitative mixture fraction measurements in flames. The measured spectra of different mixtures of natural gas and air are used to obtain the calibration parameters for local

Robustness of Distance-to-Default

DEFF Research Database (Denmark)

Jessen, Cathrine; Lando, David

2013-01-01

Distance-to-default is a remarkably robust measure for ranking firms according to their risk of default. The ranking seems to work despite the fact that the Merton model from which the measure is derived produces default probabilities that are far too small when applied to real data. We use...... simulations to investigate the robustness of the distance-to-default measure to different model specifications. Overall we find distance-to-default to be robust to a number of deviations from the simple Merton model that involve different asset value dynamics and different default triggering mechanisms....... A notable exception is a model with stochastic volatility of assets. In this case both the ranking of firms and the estimated default probabilities using distance-to-default perform significantly worse. We therefore propose a volatility adjustment of the distance-to-default measure, that significantly...

Real-time dual-comb spectroscopy with a free-running bidirectionally mode-locked fiber laser

Science.gov (United States)

Mehravar, S.; Norwood, R. A.; Peyghambarian, N.; Kieu, K.

2016-06-01

Dual-comb technique has enabled exciting applications in high resolution spectroscopy, precision distance measurements, and 3D imaging. Major advantages over traditional methods can be achieved with dual-comb technique. For example, dual-comb spectroscopy provides orders of magnitude improvement in acquisition speed over standard Fourier-transform spectroscopy while still preserving the high resolution capability. Wider adoption of the technique has, however, been hindered by the need for complex and expensive ultrafast laser systems. Here, we present a simple and robust dual-comb system that employs a free-running bidirectionally mode-locked fiber laser operating at telecommunication wavelength. Two femtosecond frequency combs (with a small difference in repetition rates) are generated from a single laser cavity to ensure mutual coherent properties and common noise cancellation. As the result, we have achieved real-time absorption spectroscopy measurements without the need for complex servo locking with accurate frequency referencing, and relatively high signal-to-noise ratio.

SO2 EMISSION MEASUREMENT BY DOAS (DIFFERENTIAL OPTICAL ABSORPTION SPECTROSCOPY AND COSPEC (CORRELATION SPECTROSCOPY AT MERAPI VOLCANO (INDONESIA

Directory of Open Access Journals (Sweden)

Hanik Humaida

2010-06-01

Full Text Available The SO2 is one of the volcanic gases that can use as indicator of volcano activity. Commonly, SO2 emission is measured by COSPEC (Correlation Spectroscopy. This equipment has several disadvantages; such as heavy, big in size, difficulty in finding spare part, and expensive. DOAS (Differential Optical Absorption Spectroscopy is a new method for SO2 emission measurement that has advantages compares to the COSPEC. Recently, this method has been developed. The SO2 gas emission measurement of Gunung Merapi by DOAS has been carried out at Kaliadem, and also by COSPEC method as comparation. The differences of the measurement result of both methods are not significant. However, the differences of minimum and maximum result of DOAS method are smaller than that of the COSPEC. It has range between 51 ton/day and 87 ton/day for DOAS and 87 ton/day and 201 ton/day for COSPEC. The measurement of SO2 gas emission evaluated with the seismicity data especially the rockfall showed the presence of the positive correlation. It may cause the gas pressure in the subsurface influencing instability of 2006 eruption lava.   Keywords: SO2 gas, Merapi, DOAS, COSPEC

Muscle metabolism of professional athletes using 31P-spectroscopy

International Nuclear Information System (INIS)

Maeurer, J.; Soellner, O.; Ehrenstein, T.; Knollmann, F.; Vogl, T.J.; Felix, R.; Konstanczak, P.; Wolff, R.

1999-01-01

Purpose: The aim of the study was to examine muscle metabolism in athletes by 31 P-spectroscopy (MRS) and to evaluate to what degree the respective resonance spectrum correlates with the kind of muscle exercise. Material and Methods: Twelve runners and 12 young ice skaters were studied by 31 P-spectroscopy of the gastrocnemic medialis muscle and the vastus medialis muscle using a surface coil at 1.5 T. Results: Sprinters displayed a higher phosphocreatinine/inorganic phosphate (PCr/Pi) and PCr/β-ATP ratios than marathon runners. The respective parameters for middle distance runners were in between. Ice skaters could prospectively be divided into sprint- and long-distance runners by our results which correlated with the athletes' training performance. Conclusion: 31 P-spectroscopy can evaluate the distribution of muscle fiber types. Thus, the athlete's potential for sprint- or long-distance running can be determined. Additional studies will have to demonstrate to what extent training may change muscle fiber distribution. (orig.)

Comparing two distance measures in the spatial mapping of food deserts: The case of Petržalka, Slovakia

Directory of Open Access Journals (Sweden)

Bilková Kristína

2017-06-01

Full Text Available Over the last twenty years or so, researchers’ attention to the issue of food deserts has increased in the geographical literature. Accessibility to large-scale retail units is one of the essential and frequently-used indicators leading to the identification and mapping of food deserts. Numerous accessibility measures of various types are available for this purpose. Euclidean distance and street network distance rank among the most frequently-used approaches, although they may lead to slightly different results. The aim of this paper is to compare various approaches to the accessibility to food stores and to assess the differences in the results gained by these methods. Accessibility was measured for residential block centroids, with applications of various accessibility measures in a GIS environment. The results suggest a strong correspondence between Euclidean distance and a little more accurate street network distance approach, applied in the case of the urban environment of Bratislava-Petržalka, Slovakia.

Density and temperature measurement using CARS spectroscopy

International Nuclear Information System (INIS)

Hirth, A.; Vollrath, K.

1979-01-01

Coherent Anti Stokes Raman Scattering (CARS) a technique derived from nonlinear optics offers two major advantages compared with the spontaneous Raman method: improved scattering efficiency and spatial coherence of the scattered signal. The theory of the coherent mixing in resonant media serves as a quantitative background of the CARS technique. A review of several applications on plasma physics and gasdynamics is given, which permits to consider the CARS spectroscopy as a potential method for nonintrusive measurement of local concentration and temperature in gas flows and reactive media. (Auth.)

CORSEN, a new software dedicated to microscope-based 3D distance measurements: mRNA-mitochondria distance, from single-cell to population analyses.

Science.gov (United States)

Jourdren, Laurent; Delaveau, Thierry; Marquenet, Emelie; Jacq, Claude; Garcia, Mathilde

2010-07-01

Recent improvements in microscopy technology allow detection of single molecules of RNA, but tools for large-scale automatic analyses of particle distributions are lacking. An increasing number of imaging studies emphasize the importance of mRNA localization in the definition of cell territory or the biogenesis of cell compartments. CORSEN is a new tool dedicated to three-dimensional (3D) distance measurements from imaging experiments especially developed to access the minimal distance between RNA molecules and cellular compartment markers. CORSEN includes a 3D segmentation algorithm allowing the extraction and the characterization of the cellular objects to be processed--surface determination, aggregate decomposition--for minimal distance calculations. CORSEN's main contribution lies in exploratory statistical analysis, cell population characterization, and high-throughput assays that are made possible by the implementation of a batch process analysis. We highlighted CORSEN's utility for the study of relative positions of mRNA molecules and mitochondria: CORSEN clearly discriminates mRNA localized to the vicinity of mitochondria from those that are translated on free cytoplasmic polysomes. Moreover, it quantifies the cell-to-cell variations of mRNA localization and emphasizes the necessity for statistical approaches. This method can be extended to assess the evolution of the distance between specific mRNAs and other cellular structures in different cellular contexts. CORSEN was designed for the biologist community with the concern to provide an easy-to-use and highly flexible tool that can be applied for diverse distance quantification issues.

Precision Spectroscopy, Diode Lasers, and Optical Frequency Measurement Technology

Science.gov (United States)

Hollberg, Leo (Editor); Fox, Richard (Editor); Waltman, Steve (Editor); Robinson, Hugh

1998-01-01

This compilation is a selected set of reprints from the Optical Frequency Measurement Group of the Time and Frequency Division of the National Institute of Standards and Technology, and consists of work published between 1987 and 1997. The two main programs represented here are (1) development of tunable diode-laser technology for scientific applications and precision measurements, and (2) research toward the goal of realizing optical-frequency measurements and synthesis. The papers are organized chronologically in five, somewhat arbitrarily chosen categories: Diode Laser Technology, Tunable Laser Systems, Laser Spectroscopy, Optical Synthesis and Extended Wavelength Coverage, and Multi-Photon Interactions and Optical Coherences.

2H{ 19F} REDOR for distance measurements in biological solids using a double resonance spectrometer

Science.gov (United States)

Grage, Stephan L.; Watts, Jude A.; Watts, Anthony

2004-01-01

A new approach for distance measurements in biological solids employing 2H{ 19F} rotational echo double resonance was developed and validated on 2H, 19F- D-alanine and an imidazopyridine based inhibitor of the gastric H +/K +-ATPase. The 2H- 19F double resonance experiments presented here were performed without 1H decoupling using a double resonance NMR spectrometer. In this way, it was possible to benefit from the relatively longer distance range of fluorine without the need of specialized fluorine equipment. A distance of 2.5 ± 0.3 Å was measured in the alanine derivative, indicating a gauche conformation of the two labels. In the case of the imidazopyridine compound a lower distance limit of 5.2 Å was determined and is in agreement with an extended conformation of the inhibitor. Several REDOR variants were compared, and their advantages and limitations discussed. Composite fluorine dephasing pulses were found to enhance the frequency bandwidth significantly, and to reduce the dependence of the performance of the experiment on the exact choice of the transmitter frequency.

PARTICULATE MATTER MEASUREMENTS USING OPEN-PATH FOURIER TRANSFORM INFRARED SPECTROSCOPY

Science.gov (United States)

Open-path Fourier transform infrared (OP-FT1R) spectroscopy is an accepted technology for measuring gaseous air contaminants. OP-FT1R absorbance spectra acquired during changing aerosols conditions reveal related changes in very broad baseline features. Usually, this shearing of ...

Measurement repeatability of tibial tuberosity-trochlear groove offset distance in red fox (Vulpes vulpes) cadavers

NARCIS (Netherlands)

Miles, J.E.; Jensen, B.R.; Kirpensteijn, J.; Svalastoga, E.L.; Eriksen, T.

2013-01-01

Abstract OBJECTIVE: To describe CT image reconstruction criteria for measurement of the tibial tuberosity-trochlear groove (TT-TG) offset distance, evaluate intra- and inter-reconstruction repeatability, and identify key sources of error in the measurement technique, as determined in vulpine hind

The Distance Standard Deviation

OpenAIRE

Edelmann, Dominic; Richards, Donald; Vogel, Daniel

2017-01-01

The distance standard deviation, which arises in distance correlation analysis of multivariate data, is studied as a measure of spread. New representations for the distance standard deviation are obtained in terms of Gini's mean difference and in terms of the moments of spacings of order statistics. Inequalities for the distance variance are derived, proving that the distance standard deviation is bounded above by the classical standard deviation and by Gini's mean difference. Further, it is ...

Redox behaviors of iron by absorption spectroscopy and redox potential measurement

International Nuclear Information System (INIS)

Oh, Jae Yong

2010-02-01

This work is performed to study the redox (reduction/oxidation) behaviors of iron in aqueous system by a combination of absorption spectroscopy and redox potential measurements. There are many doubts on redox potential measurements generally showing low accuracies and high uncertainties. In the present study, redox potentials are measured by utilizing various redox electrodes such as Pt, Au, Ag, and glassy carbon (GC) electrodes. Measured redox potentials are compared with calculated redox potentials based on the chemical oxidation speciation of iron and thermodynamic data by absorption spectroscopy, which provides one of the sensitive and selective spectroscopic methods for the chemical speciation of Fe(II/III). From the comparison analyses, redox potential values measured by the Ag redox electrode are fairly consistent with those calculated by the chemical aqueous speciation of iron in the whole system. In summary, the uncertainties of measured redox potentials are closely related with the total Fe concentration and affected by the formation of mixed potentials due to Fe(III) precipitates in the pH range of 6 ∼ 9 beyond the solubility of Fe(III), whilst being independent of the initially prepared concentration ratios between Fe(II) and Fe(III)

Experimental approaches for the development of gamma spectroscopy well logging system

Energy Technology Data Exchange (ETDEWEB)

Shin, Jehyun; Hwang, Seho; Kim, Jongman [Korea Institute of Geoscience and Mineral Resources (124 Gwahang-no, Yuseong-gu, Daejeon, Korea) (Korea, Republic of); Won, Byeongho [Heesong Geotek Co., Ltd (146-8 Sangdaewon-dong, Jungwon-gu, Seongnam-si, Gyeonggi-do, Korea) (Korea, Republic of)

2015-03-10

This article discusses experimental approaches for the development of gamma spectroscopy well logging system. Considering the size of borehole sonde, we customize 2 x 2 inches inorganic scintillators and the system including high voltage, preamplifier, amplifier and multichannel analyzer (MCA). The calibration chart is made by test using standard radioactive sources so that the measured count rates are expressed by energy spectrum. Optimum high-voltage supplies and the measurement parameters of each detector are set up by experimental investigation. Also, the responses of scintillation detectors have been examined by analysis according to the distance between source and detector. Because gamma spectroscopy well logging needs broad spectrum, high sensitivity and resolution, the energy resolution and sensitivity as a function of gamma ray energy are investigated by analyzing the gamma ray activities of the radioactive sources.

REPRESENTATIONS OF DISTANCE: DIFFERENCES IN UNDERSTANDING DISTANCE ACCORDING TO TRAVEL METHOD

Directory of Open Access Journals (Sweden)

Gunvor Riber Larsen

2017-12-01

Full Text Available This paper explores how Danish tourists represent distance in relation to their holiday mobility and how these representations of distance are a result of being aero-mobile as opposed to being land-mobile. Based on interviews with Danish tourists, whose holiday mobility ranges from the European continent to global destinations, the first part of this qualitative study identifies three categories of representations of distance that show how distance is being ‘translated’ by the tourists into non-geometric forms: distance as resources, distance as accessibility, and distance as knowledge. The representations of distance articulated by the Danish tourists show that distance is often not viewed in ‘just’ kilometres. Rather, it is understood in forms that express how transcending the physical distance through holiday mobility is dependent on individual social and economic contexts, and on whether the journey was undertaken by air or land. The analysis also shows that being aeromobile is the holiday transportation mode that removes the tourists the furthest away from physical distance, resulting in the distance travelled by air being represented in ways that have the least correlation, in the tourists’ minds, with physical distance measured in kilometres.

Machine learning enhanced optical distance sensor

Science.gov (United States)

Amin, M. Junaid; Riza, N. A.

2018-01-01

Presented for the first time is a machine learning enhanced optical distance sensor. The distance sensor is based on our previously demonstrated distance measurement technique that uses an Electronically Controlled Variable Focus Lens (ECVFL) with a laser source to illuminate a target plane with a controlled optical beam spot. This spot with varying spot sizes is viewed by an off-axis camera and the spot size data is processed to compute the distance. In particular, proposed and demonstrated in this paper is the use of a regularized polynomial regression based supervised machine learning algorithm to enhance the accuracy of the operational sensor. The algorithm uses the acquired features and corresponding labels that are the actual target distance values to train a machine learning model. The optimized training model is trained over a 1000 mm (or 1 m) experimental target distance range. Using the machine learning algorithm produces a training set and testing set distance measurement errors of learning. Applications for the proposed sensor include industrial scenario distance sensing where target material specific training models can be generated to realize low <1% measurement error distance measurements.

Diagnosis of laser ablated carbon particles measured by time-resolved X-ray absorption spectroscopy

International Nuclear Information System (INIS)

Miyashita, Atsumi; Yoda, Osamu; Ohyanagi, T.; Murakami, K.

1995-01-01

The time and space resolved properties of laser ablated carbon particles were measured by X-ray absorption spectroscopy using LPX as an X-ray source. The energy density of the irradiation laser on the sample was in the range of 0.5-20J/cm 2 and the time delay was varied between 0 and 120ns. The absorption spectra exhibited several peaks originated from level to level transitions and an intense broad absorption in the energy range of C-K edge. At a delay time of 120ns, the absorption peak from 1s→2p transition of neutral carbon atom (C 0 ), C - , C + and C 2+ ions were observed. The absorption peak from C 0 was stronger as the probing position was closer to the sample surface and decreased rapidly with distance from the sample surface. The absorption peak C 2+ ion was observed only at comparatively distant positions from surface. The maximum speeds of highly charged ions were faster than that of neutral atoms and negative charged ions. The neutral atom and lower charged ions were emitted from the sample even after laser irradiation. The spatial distributions of the laser ablated carbon particles in the localized helium gas environment were measured. In the helium gas environment, the ablation plume was depressed by the helium cloud generated on the top of ablation plume. (author)

Lifetime measurements and decay spectroscopy of 132I

Directory of Open Access Journals (Sweden)

Bhattacharyya S.

2014-03-01

Full Text Available The low-lying states of odd-odd 132I, the 3p-3h nucleus with respect to the doubly magic 132Sn, have been characterized from decay spectroscopy. The neutron rich Iodine and Tellurium isotopes have been produced as fission product of alpha-induced fission of 235U and radiochemically separated. The life-time of the first excited state of 132I have been precisely measured using LaBr3(Ce scintillators from the decay of 132Te. The IT decay of the high spin isomer (8- in 132I has been measured with a Low Energy Photon Spectrometer (LEPS of segmented planar Ge detector.

Transcutaneous Measurement of Blood Analyte Concentration Using Raman Spectroscopy

Science.gov (United States)

Barman, Ishan; Singh, Gajendra P.; Dasari, Ramachandra R.; Feld, Michael S.

2008-11-01

Diabetes mellitus is a chronic disorder, affecting nearly 200 million people worldwide. Acute complications, such as hypoglycemia, cardiovascular disease and retinal damage, may occur if the disease is not adequately controlled. As diabetes has no known cure, tight control of glucose levels is critical for the prevention of such complications. Given the necessity for regular monitoring of blood glucose, development of non-invasive glucose detection devices is essential to improve the quality of life in diabetic patients. The commercially available glucose sensors measure the interstitial fluid glucose by electrochemical detection. However, these sensors have severe limitations, primarily related to their invasive nature and lack of stability. This necessitates the development of a truly non-invasive glucose detection technique. NIR Raman Spectroscopy, which combines the substantial penetration depth of NIR light with the excellent chemical specificity of Raman spectroscopy, provides an excellent tool to meet the challenges involved. Additionally, it enables simultaneous determination of multiple blood analytes. Our laboratory has pioneered the use of Raman spectroscopy for blood analytes' detection in biological media. The preliminary success of our non-invasive glucose measurements both in vitro (such as in serum and blood) and in vivo has provided the foundation for the development of feasible clinical systems. However, successful application of this technology still faces a few hurdles, highlighted by the problems of tissue luminescence and selection of appropriate reference concentration. In this article we explore possible avenues to overcome these challenges so that prospective prediction accuracy of blood analytes can be brought to clinically acceptable levels.

Implementation of a lock-in amplifier for optical spectroscopy measurement

International Nuclear Information System (INIS)

Homs, R.; Puron, E.

2012-01-01

The experimental set-up of an optical spectroscopy measurement based on virtual instrumentation is presented. A lock-in amplifier has been implemented by applying digital signal processing techniques to a PC-based data acquisition board. The application was developed in C++, on top of open source Qt/Qwt graphical framework. The emission spectral of reference light sources were measured in order to calibrate and validate the system. (Author)

Anogenital distance and penile width measurements in The Infant Development and the Environment Study (TIDES): methods and predictors.

Science.gov (United States)

Sathyanarayana, Sheela; Grady, Richard; Redmon, J B; Ivicek, Kristy; Barrett, Emily; Janssen, Sarah; Nguyen, Ruby; Swan, Shanna H

2015-04-01

Anogenital distance (AGD) is an androgen responsive anatomic measurement that may have significant utility in clinical and epidemiological research studies. We describe development of standardized measurement methods and predictors of AGD outcomes. We examined infants born to 758 participants in The Infant Development and the Environment Study (TIDES cohort) in four clinical centers in 2011-2013. We developed and implemented a detailed training protocol that incorporated multiple quality control (QC) measures. In males, we measured anoscrotal distance (AGDAS), anopenile distance (AGDAP), and penile width (PW) and in females, anofourchette distance (AGDAF,) and anoclitoral distance (AGDAC). A single examiner obtained three repetitions of all measurements, and a second examiner obtained independent measurements for 14% of infants. We used the intra-rater ICC to assess within-examiner variability and the inter-rater ICC to assess between-examiner variability. We used multivariable linear regression to examine predictors of AGD outcomes including: gestational age at birth, birth weight, gestational age, several measures of body size, race, maternal age, and study center. In the full TIDES cohort, including 758 mothers and children, significant predictors of AGD and PW included: age at exam, gestational age at birth, weight-for-length Z-score, maternal age and study center. In 371 males, the mean (SD) AGDAS, AGDAP, and PW were 24.7 (4.5), 49.6 (5.9), and 10.8 (1.3) mm, respectively. In 387 females, the mean (SD) AGDAF and AGDAC were 16.0 (3.2) mm and 36.7 (3.8) mm, respectively. The intra-examiner ICC and inter-examiner ICC averaged over all subjects and examiners were between 0.89-0.92 and 0.69-0.84 respectively. Our study confirms that with appropriate training and quality control measures, AGD and PW measurements can be performed reliably and accurately in male and female infants. In order for reliable interpretation, these measurements should be adjusted for

[Hyperfine structure and isotope shift measurements of short lived elements by laser spectroscopy

International Nuclear Information System (INIS)

Schuessler, H.A.

1986-01-01

The aim of this research is to determine nuclear moments and charge distributions of short-lived isotopes produced both on-line and off-line to a nuclear facility. These measurements give detailed information on the nuclear force and are used to test current nuclear models. The small amounts of nuclei which can be produced off stability constitute the challenge in these experiments. Presently mainly neutron-rich isotopes are being studied by three ultrasensitive high-resolution laser techniques. These are collinear fast ion-beam laser spectroscopy, stored-ion laser spectroscopy and fluorescence spectroscopy. 5 figs

Correlation between near infrared spectroscopy and electrical techniques in measuring skin moisture content

International Nuclear Information System (INIS)

Mohamad, M; Sabbri, A R M; Jafri, M Z Mat; Omar, A F

2014-01-01

Near infrared (NIR) spectroscopy technique serves as an important tool for the measurement of moisture content of skin owing to the advantages it has over the other techniques. The purpose of the study is to develop a correlation between NIR spectrometer with electrical conventional techniques for skin moisture measurement. A non-invasive measurement of moisture content of skin was performed on different part of human face and hand under control environment (temperature 21 ± 1 °C, relative humidity 45 ± 5 %). Ten healthy volunteers age between 21-25 (male and female) participated in this study. The moisture content of skin was measured using DermaLab ® USB Moisture Module, Scalar Moisture Checker and NIR spectroscopy (NIRQuest). Higher correlation was observed between NIRQuest and Dermalab moisture probe with a coefficient of determination (R 2 ) above 70 % for all the subjects. However, the value of R 2 between NIRQuest and Moisture Checker was observed to be lower with the R 2 values ranges from 51.6 to 94.4 %. The correlation of NIR spectroscopy technique successfully developed for measuring moisture content of the skin. The analysis of this correlation can help to establish novel instruments based on an optical system in clinical used especially in the dermatology field

Measuring Astronomical Distances with Linear Programming

Science.gov (United States)

Narain, Akshar

2015-01-01

A few years ago it was suggested that the distance to celestial bodies could be computed by tracking their position over about 24 hours and then solving a regression problem. One only needed to use inexpensive telescopes, cameras, and astrometry tools, and the experiment could be done from one's backyard. However, it is not obvious to an amateur…

Pulse EPR distance measurements to study multimers and multimerisation

Science.gov (United States)

Ackermann, Katrin; Bode, Bela E.

2018-06-01

Pulse dipolar electron paramagnetic resonance (PD-EPR) has become a powerful tool for structural biology determining distances on the nanometre scale. Recent advances in hardware, methodology, and data analysis have widened the scope to complex biological systems. PD-EPR can be applied to systems containing lowly populated conformers or displaying large intrinsic flexibility, making them all but intractable for cryo-electron microscopy and crystallography. Membrane protein applications are of particular interest due to the intrinsic difficulties for obtaining high-resolution structures of all relevant conformations. Many drug targets involved in critical cell functions are multimeric channels or transporters. Here, common approaches for introducing spin labels for PD-EPR cause the presence of more than two electron spins per multimeric complex. This requires careful experimental design to overcome detrimental multi-spin effects and to secure sufficient distance resolution in presence of multiple distances. In addition to obtaining mere distances, PD-EPR can also provide information on multimerisation degrees allowing to study binding equilibria and to determine dissociation constants.

The Distance to M51

Science.gov (United States)

McQuinn, Kristen. B. W.; Skillman, Evan D.; Dolphin, Andrew E.; Berg, Danielle; Kennicutt, Robert

2016-07-01

Great investments of observing time have been dedicated to the study of nearby spiral galaxies with diverse goals ranging from understanding the star formation process to characterizing their dark matter distributions. Accurate distances are fundamental to interpreting observations of these galaxies, yet many of the best studied nearby galaxies have distances based on methods with relatively large uncertainties. We have started a program to derive accurate distances to these galaxies. Here we measure the distance to M51—the Whirlpool galaxy—from newly obtained Hubble Space Telescope optical imaging using the tip of the red giant branch method. We measure the distance modulus to be 8.58 ± 0.10 Mpc (statistical), corresponding to a distance modulus of 29.67 ± 0.02 mag. Our distance is an improvement over previous results as we use a well-calibrated, stable distance indicator, precision photometry in a optimally selected field of view, and a Bayesian Maximum Likelihood technique that reduces measurement uncertainties. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

Fast Computing for Distance Covariance

OpenAIRE

Huo, Xiaoming; Szekely, Gabor J.

2014-01-01

Distance covariance and distance correlation have been widely adopted in measuring dependence of a pair of random variables or random vectors. If the computation of distance covariance and distance correlation is implemented directly accordingly to its definition then its computational complexity is O($n^2$) which is a disadvantage compared to other faster methods. In this paper we show that the computation of distance covariance and distance correlation of real valued random variables can be...

Spatially-Scanned Dual Comb Spectroscopy for Atmospheric Measurements

Science.gov (United States)

Cossel, K.; Waxman, E.; Giorgetta, F.; Cermak, M.; Coddington, I.; Hesselius, D.; Ruben, S.; Swann, W.; Rieker, G. B.; Newbury, N.

2017-12-01

Measuring trace gas emissions from sources that are spatially complex and temporally variable, such as leaking natural gas infrastructure, is challenging with current measurement systems. Here, we present a new technique that provides the path-integrated concentrations of multiple gas species between a ground station and a retroreflector mounted on a small quadcopter. Such a system could provide the ability to quantify small area emissions sources as well measure vertical mixing within the boundary layer. The system is based on a near-infrared dual frequency-comb spectroscopy system (DCS) covering 1.58-1.7 microns, which enables rapid, accurate measurements of CO2, CH4, H2O, and HDO. The eye-safe laser light is launched from a telescope on a fast azimuth, elevation gimbal to a small quadcopter carrying a lightweight retroreflector as well as a high-precision real-time kinematic GPS receiver (for real-time cm-level path length measurements) and pressure, temperature and humidity sensors. Here, we show the results of test measurements from controlled releases of CH4 as well as from test vertical profiles.

Intersubunit distances in full-length, dimeric, bacterial phytochrome Agp1, as measured by pulsed electron-electron double resonance (PELDOR) between different spin label positions, remain unchanged upon photoconversion.

Science.gov (United States)

Kacprzak, Sylwia; Njimona, Ibrahim; Renz, Anja; Feng, Juan; Reijerse, Edward; Lubitz, Wolfgang; Krauss, Norbert; Scheerer, Patrick; Nagano, Soshichiro; Lamparter, Tilman; Weber, Stefan

2017-05-05

Bacterial phytochromes are dimeric light-regulated histidine kinases that convert red light into signaling events. Light absorption by the N-terminal photosensory core module (PCM) causes the proteins to switch between two spectrally distinct forms, Pr and Pfr, thus resulting in a conformational change that modulates the C-terminal histidine kinase region. To provide further insights into structural details of photoactivation, we investigated the full-length Agp1 bacteriophytochrome from the soil bacterium Agrobacterium fabrum using a combined spectroscopic and modeling approach. We generated seven mutants suitable for spin labeling to enable application of pulsed EPR techniques. The distances between attached spin labels were measured using pulsed electron-electron double resonance spectroscopy to probe the arrangement of the subunits within the dimer. We found very good agreement of experimental and calculated distances for the histidine-kinase region when both subunits are in a parallel orientation. However, experimental distance distributions surprisingly showed only limited agreement with either parallel- or antiparallel-arranged dimer structures when spin labels were placed into the PCM region. This observation indicates that the arrangements of the PCM subunits in the full-length protein dimer in solution differ significantly from that in the PCM crystals. The pulsed electron-electron double resonance data presented here revealed either no or only minor changes of distance distributions upon Pr-to-Pfr photoconversion. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

In-Situ Measurement of Chirality of Molecules and Molecular Assemblies with Surface Nonlinear Spectroscopy

International Nuclear Information System (INIS)

Wang, Hongfei

2012-01-01

Developments in quantitative measurement and analysis in nonlinear surface spectroscopy, namely, second harmonic generation linear dichroism (SHG-LD) and sum frequency generation vibrational spectroscopy linear dichroism (SFG-VS-LD), provide new opportunities for probing the surface chirality of monolayers and thin films. In this book chapter, the up-to-date theoretical background and experimental methodology, as well as examples and future perspectives on the developments with surface nonlinear spectroscopy in surface chirality studies are to be summarized and outlined for general readers.

Cepheids Geometrical Distances Using Space Interferometry

Science.gov (United States)

Marengo, M.; Karovska, M.; Sasselov, D. D.; Sanchez, M.

2004-05-01

A space based interferometer with a sub-milliarcsecond resolution in the UV-optical will provide a new avenue for the calibration of primary distance indicators with unprecedented accuracy, by allowing very accurate and stable measurements of Cepheids pulsation amplitudes at wavelengths not accessible from the ground. Sasselov & Karovska (1994) have shown that interferometers allow very accurate measurements of Cepheids distances by using a ``geometric'' variant of the Baade-Wesselink method. This method has been succesfully applied to derive distances and radii of nearby Cepheids using ground-based near-IR and optical interferometers, within a 15% accuracy level. Our study shows that the main source of error in these measurements is due to the perturbing effects of the Earth atmosphere, which is the limiting factor in the interferometer stability. A space interferometer will not suffer from this intrinsic limitations, and can potentially lead to improve astronomical distance measurements by an order of magnitude in precision. We discuss here the technical requirements that a space based facility will need to carry out this project, allowing distance measurements within a few percent accuracy level. We will finally discuss how a sub-milliarcsecond resolution will allow the direct distance determination for hundreds of galactic sources, and provide a substantial improvement in the zero-point of the Cepheid distance scale.

Time domain simulation of Gd3+-Gd3+ distance measurements by EPR

Science.gov (United States)

Manukovsky, Nurit; Feintuch, Akiva; Kuprov, Ilya; Goldfarb, Daniella

2017-07-01

Gd3+-based spin labels are useful as an alternative to nitroxides for intramolecular distance measurements at high fields in biological systems. However, double electron-electron resonance (DEER) measurements using model Gd3+ complexes featured a low modulation depth and an unexpected broadening of the distance distribution for short Gd3+-Gd3+ distances, when analysed using the software designed for S = 1/2 pairs. It appears that these effects result from the different spectroscopic characteristics of Gd3+—the high spin, the zero field splitting (ZFS), and the flip-flop terms in the dipolar Hamiltonian that are often ignored for spin-1/2 systems. An understanding of the factors affecting the modulation frequency and amplitude is essential for the correct analysis of Gd3+-Gd3+ DEER data and for the educated choice of experimental settings, such as Gd3+ spin label type and the pulse parameters. This work uses time-domain simulations of Gd3+-Gd3+ DEER by explicit density matrix propagation to elucidate the factors shaping Gd3+ DEER traces. The simulations show that mixing between the |+½, -½> and |-½, +½> states of the two spins, caused by the flip-flop term in the dipolar Hamiltonian, leads to dampening of the dipolar modulation. This effect may be mitigated by a large ZFS or by pulse frequency settings allowing for a decreased contribution of the central transition and the one adjacent to it. The simulations reproduce both the experimental line shapes of the Fourier-transforms of the DEER time domain traces and the trends in the behaviour of the modulation depth, thus enabling a more systematic design and analysis of Gd3+ DEER experiments.

Accuracy of Positioning Autonomous Biomimetic Underwater Vehicle Using Additional Measurement of Distances

Directory of Open Access Journals (Sweden)

Naus Krzysztof

2016-12-01

Full Text Available The article describes a study of problem of estimating the position coordinates of Autonomous Biomimetic Underwater Vehicle (ABUV using two methods: dead reckoning (DR and extended Kalman filter (EKF. In the first part of the paper, navigation system of ABUV is described and scientific problem with underwater positioning is formulated. The main part describes a way of estimating the position coordinates using DR and EKF and a numerical experiment involving motion of ABUV along the predetermined test distance. The final part of the paper contains a comparative statistical analysis of the results, carried out for assessing the accuracy of estimation of the position coordinates using DR and EKF methods. It presents the generalized conclusions from the research and the problems relating to the proper placement of the components of the system measuring distances.

Note: Electron energy spectroscopy mapping of surface with scanning tunneling microscope.

Science.gov (United States)

Li, Meng; Xu, Chunkai; Zhang, Panke; Li, Zhean; Chen, Xiangjun

2016-08-01

We report a novel scanning probe electron energy spectrometer (SPEES) which combines a double toroidal analyzer with a scanning tunneling microscope to achieve both topography imaging and electron energy spectroscopy mapping of surface in situ. The spatial resolution of spectroscopy mapping is determined to be better than 0.7 ± 0.2 μm at a tip sample distance of 7 μm. Meanwhile, the size of the field emission electron beam spot on the surface is also measured, and is about 3.6 ± 0.8 μm in diameter. This unambiguously demonstrates that the spatial resolution of SPEES technique can be much better than the size of the incident electron beam.

Note: Electron energy spectroscopy mapping of surface with scanning tunneling microscope

Energy Technology Data Exchange (ETDEWEB)

Li, Meng; Xu, Chunkai, E-mail: xuck@ustc.edu.cn, E-mail: xjun@ustc.edu.cn; Zhang, Panke; Li, Zhean; Chen, Xiangjun, E-mail: xuck@ustc.edu.cn, E-mail: xjun@ustc.edu.cn [Hefei National Laboratory for Physical Science at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026 (China)

2016-08-15

We report a novel scanning probe electron energy spectrometer (SPEES) which combines a double toroidal analyzer with a scanning tunneling microscope to achieve both topography imaging and electron energy spectroscopy mapping of surface in situ. The spatial resolution of spectroscopy mapping is determined to be better than 0.7 ± 0.2 μm at a tip sample distance of 7 μm. Meanwhile, the size of the field emission electron beam spot on the surface is also measured, and is about 3.6 ± 0.8 μm in diameter. This unambiguously demonstrates that the spatial resolution of SPEES technique can be much better than the size of the incident electron beam.

Note: Electron energy spectroscopy mapping of surface with scanning tunneling microscope

International Nuclear Information System (INIS)

Li, Meng; Xu, Chunkai; Zhang, Panke; Li, Zhean; Chen, Xiangjun

2016-01-01

We report a novel scanning probe electron energy spectrometer (SPEES) which combines a double toroidal analyzer with a scanning tunneling microscope to achieve both topography imaging and electron energy spectroscopy mapping of surface in situ. The spatial resolution of spectroscopy mapping is determined to be better than 0.7 ± 0.2 μm at a tip sample distance of 7 μm. Meanwhile, the size of the field emission electron beam spot on the surface is also measured, and is about 3.6 ± 0.8 μm in diameter. This unambiguously demonstrates that the spatial resolution of SPEES technique can be much better than the size of the incident electron beam.

Correlation measure to detect time series distances, whence economy globalization

Science.gov (United States)

Miśkiewicz, Janusz; Ausloos, Marcel

2008-11-01

An instantaneous time series distance is defined through the equal time correlation coefficient. The idea is applied to the Gross Domestic Product (GDP) yearly increments of 21 rich countries between 1950 and 2005 in order to test the process of economic globalisation. Some data discussion is first presented to decide what (EKS, GK, or derived) GDP series should be studied. Distances are then calculated from the correlation coefficient values between pairs of series. The role of time averaging of the distances over finite size windows is discussed. Three network structures are next constructed based on the hierarchy of distances. It is shown that the mean distance between the most developed countries on several networks actually decreases in time, -which we consider as a proof of globalization. An empirical law is found for the evolution after 1990, similar to that found in flux creep. The optimal observation time window size is found ≃15 years.

Measurement of the band gap by reflection electron energy loss spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Vos, Maarten, E-mail: maarten.vos@anu.edu.au [Electronic Materials Engineering Department, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); King, Sean W. [Logic Technology Development, Intel Corporation, Hillsboro, OR 97124 (United States); French, Benjamin L. [Ocotillo Materials Laboratory, Intel Corporation, Chandler, AZ 85248 (United States)

2016-10-15

Highlights: • Semiconductors are measured (without surface preparation) using REELS. • At low beam energies it is difficult to measure band gap due to surface impurities. • At very high energies it is difficult to measure band gap due to recoil effect. • At intermediate energies (around 5 keV) one obtains a good estimate of the band gap. - Abstract: We investigate the possibilities of measuring the band gap of a variety of semiconductors and insulators by reflection electron energy loss spectroscopy without additional surface preparation. The band gap is a bulk property, whereas reflection energy loss spectroscopy is generally considered a surface sensitive technique. By changing the energy of the incoming electrons, the degree of surface sensitivity can be varied. Here, we present case studies to determine the optimum condition for the determination of the band gap. At very large incoming electron energies recoil effects interfere with the band gap determination, whereas at very low energies surface effects are obscuring the band gap without surface preparation. Using an incoming energy of 5 keV a reasonable estimate of the band gap is obtained in most cases.

Measurement of the band gap by reflection electron energy loss spectroscopy

International Nuclear Information System (INIS)

Vos, Maarten; King, Sean W.; French, Benjamin L.

2016-01-01

Highlights: • Semiconductors are measured (without surface preparation) using REELS. • At low beam energies it is difficult to measure band gap due to surface impurities. • At very high energies it is difficult to measure band gap due to recoil effect. • At intermediate energies (around 5 keV) one obtains a good estimate of the band gap. - Abstract: We investigate the possibilities of measuring the band gap of a variety of semiconductors and insulators by reflection electron energy loss spectroscopy without additional surface preparation. The band gap is a bulk property, whereas reflection energy loss spectroscopy is generally considered a surface sensitive technique. By changing the energy of the incoming electrons, the degree of surface sensitivity can be varied. Here, we present case studies to determine the optimum condition for the determination of the band gap. At very large incoming electron energies recoil effects interfere with the band gap determination, whereas at very low energies surface effects are obscuring the band gap without surface preparation. Using an incoming energy of 5 keV a reasonable estimate of the band gap is obtained in most cases.

Coherent dual-frequency lidar system design for distance and speed measurements

Science.gov (United States)

Zheng, Xingyuan; Zhao, Changming; Zhang, Haiyang; Zheng, Zheng; Yang, Hongzhi

2018-01-01

Lidars have a wide range of applications in military detection and civilian remote sensing. Coherent Dual-Frequency Lidar (CDFL) is a new concept of laser radar that is using electrical coherence instead of optical coherence. It uses laser with two coherent frequency components as transmitting wave. The method is based on the use of an optically-carried radio frequency (RF) signal, which is the frequency difference between the two components, which is specially designed for distance and speed measurements. It not only ensures the system has the characteristics of high spatial resolution, high ranging and velocity precision of laser radar, but also can use mature signal processing technology of microwave radar, and it is a research direction that attracts more concern in recent years. A CDFL detection system is constructed and field experiment is carried out. In the system, a narrow linewidth fiber laser with a wavelength of 1064nm is adopted. The dual-frequency laser with frequency difference of 200MHz and 200.6MHz is obtained by acousto-optic frequency shift and recombination. The maximum output power of dual frequency laser is 200mW. The receiver consists of all-fiber balanced InGaAs photo-detector and homemade analog signal processing board. The experimental results show that the distance resolution and velocity resolution of the system are 0.1m and 0.1m/s separately when the working distance is greater than 200m, and the spatial resolution is 0.5mrad.

Quality Assurance of Distance Education: Multiple Assessment Measures Used in a Business, Career, and Technical Education Department

Directory of Open Access Journals (Sweden)

Dr. Elizabeth HODGE

2004-04-01

Full Text Available Quality Assurance of Distance Education: Multiple Assessment Measures Used in a Business, Career, and Technical Education Department Assistant Professor Dr. Shelia TUCKER East Carolina University, Greenville, NC, USA Assistant Professor Dr. Elizabeth HODGE East Carolina University, Greenville, NC, USA ABSTRACT Educational institutions are being encouraged by accrediting agencies to move beyond the traditional measures of success such as satisfaction surveys from students, employers, and alumni. They stress the use of a variety of measurement tools to audit students’ work. Thus, this study will seek to identify multiple assessment strategies that can be used to evaluate the effectiveness of distance education courses within an entire degree program. Comparisons of three courses being taught simultaneously on line and in the classroom were made. There were no significant differences noted in student outcomes assessments. Additionally, the same assessment measures used for SACS for the traditional classroom were equated with the distance education classes for those in the field of Family and Consumer Sciences, Business Education, the BE/ME program, the MAEd program in Technical teaching, and Information Technologies. No significant differences were noted in student outcomes assessments.

Next generation laser-based standoff spectroscopy techniques for Mars exploration.

Science.gov (United States)

Gasda, Patrick J; Acosta-Maeda, Tayro E; Lucey, Paul G; Misra, Anupam K; Sharma, Shiv K; Taylor, G Jeffrey

2015-01-01

In the recent Mars 2020 Rover Science Definition Team Report, the National Aeronautics and Space Administration (NASA) has sought the capability to detect and identify elements, minerals, and most importantly, biosignatures, at fine scales for the preparation of a retrievable cache of samples. The current Mars rover, the Mars Science Laboratory Curiosity, has a remote laser-induced breakdown spectroscopy (LIBS) instrument, a type of quantitative elemental analysis, called the Chemistry Camera (ChemCam) that has shown that laser-induced spectroscopy instruments are not only feasible for space exploration, but are reliable and complementary to traditional elemental analysis instruments such as the Alpha Particle X-Ray Spectrometer. The superb track record of ChemCam has paved the way for other laser-induced spectroscopy instruments, such as Raman and fluorescence spectroscopy. We have developed a prototype remote LIBS-Raman-fluorescence instrument, Q-switched laser-induced time-resolved spectroscopy (QuaLITy), which is approximately 70 000 times more efficient at recording signals than a commercially available LIBS instrument. The increase in detection limits and sensitivity is due to our development of a directly coupled system, the use of an intensified charge-coupled device image detector, and a pulsed laser that allows for time-resolved measurements. We compare the LIBS capabilities of our system with an Ocean Optics spectrometer instrument at 7 m and 5 m distance. An increase in signal-to-noise ratio of at least an order of magnitude allows for greater quantitative analysis of the elements in a LIBS spectrum with 200-300 μm spatial resolution at 7 m, a Raman instrument capable of 1 mm spatial resolution at 3 m, and bioorganic fluorescence detection at longer distances. Thus, the new QuaLITy instrument fulfills all of the NASA expectations for proposed instruments.

Distance measurement and wave dispersion in a Liouville-string approach to quantum gravity

CERN Document Server

Amelino-Camelia, G; Mavromatos, Nikolaos E; Nanopoulos, Dimitri V

1997-01-01

Within a Liouville approach to non-critical string theory, we discuss space-time foam effects on the propagation of low-energy particles. We find an induced frequency-dependent dispersion in the propagation of a wave packet, and observe that this would affect the outcome of measurements involving low-energy particles as probes. In particular, the maximum possible order of magnitude of the space-time foam effects would give rise to an error in the measurement of distance comparable to that independently obtained in some recent heuristic quantum-gravity analyses. We also briefly compare these error estimates with the precision of astrophysical measurements.

Modern Geometric Methods of Distance Determination

Science.gov (United States)

Thévenin, Frédéric; Falanga, Maurizio; Kuo, Cheng Yu; Pietrzyński, Grzegorz; Yamaguchi, Masaki

2017-11-01

Building a 3D picture of the Universe at any distance is one of the major challenges in astronomy, from the nearby Solar System to distant Quasars and galaxies. This goal has forced astronomers to develop techniques to estimate or to measure the distance of point sources on the sky. While most distance estimates used since the beginning of the 20th century are based on our understanding of the physics of objects of the Universe: stars, galaxies, QSOs, the direct measures of distances are based on the geometric methods as developed in ancient Greece: the parallax, which has been applied to stars for the first time in the mid-19th century. In this review, different techniques of geometrical astrometry applied to various stellar and cosmological (Megamaser) objects are presented. They consist in parallax measurements from ground based equipment or from space missions, but also in the study of binary stars or, as we shall see, of binary systems in distant extragalactic sources using radio telescopes. The Gaia mission will be presented in the context of stellar physics and galactic structure, because this key space mission in astronomy will bring a breakthrough in our understanding of stars, galaxies and the Universe in their nature and evolution with time. Measuring the distance to a star is the starting point for an unbiased description of its physics and the estimate of its fundamental parameters like its age. Applying these studies to candles such as the Cepheids will impact our large distance studies and calibration of other candles. The text is constructed as follows: introducing the parallax concept and measurement, we shall present briefly the Gaia satellite which will be the future base catalogue of stellar astronomy in the near future. Cepheids will be discussed just after to demonstrate the state of the art in distance measurements in the Universe with these variable stars, with the objective of 1% of error in distances that could be applied to our closest

First neutron spectroscopy measurements with a pixelated diamond detector at JET

Energy Technology Data Exchange (ETDEWEB)

Muraro, A., E-mail: muraro@ifp.cnr.it; Giacomelli, L.; Grosso, G.; Tardocchi, M. [Istituto di Fisica del Plasma “P. Caldirola,” CNR, Milano (Italy); Nocente, M.; Rebai, M.; Rigamonti, D.; Gorini, G. [Istituto di Fisica del Plasma “P. Caldirola,” CNR, Milano (Italy); University of Milano Bicocca, Piazza della Scienza 3, 20126 Milano (Italy); Belli, F. [Centro Ricerca ENEA-Frascati, Via E.Fermi 45, Frascati, Rome (Italy); Calvani, P.; Girolami, M.; Trucchi, D. M. [CNR—Istituto di Struttura della Materia (ISM), Via Salaria km 29.300, 00015 Monterotondo Scalo, Rome (Italy); Figueiredo, J. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisbon (Portugal); EUROfusion Programme Management Unit, Culham Science Centre, Abingdon (United Kingdom); Murari, A. [Culham Centre for Fusion Energy, Culham (United Kingdom); Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Padova (Italy); Popovichev, S. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisbon (Portugal); Collaboration: EUROfusion Consortium, JET, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

2016-11-15

A prototype Single crystal Diamond Detector (SDD) was installed at the Joint European Torus (JET) in 2013 along an oblique line of sight and demonstrated the possibility to carry out neutron spectroscopy measurements with good energy resolution and detector stability in discharges heated by neutral beam injection and radio-frequency waves. Starting from these positive results, within the Vertical Neutron Spectrometer project of the Joint European Torus, we have developed a pixelated instrument consisting of a matrix of 12 independent SDDs, called the Diamond Vertical Neutron Spectrometer (DVNS), which boosts the detection efficiency of a single SDD by an order of magnitude. In this paper we describe the main features of the DVNS, including the detector design, energy resolution, and data acquisition system for on-line processing. Preliminary spectroscopy measurements of 2.5 MeV neutrons from the present deuterium plasma at JET are finally presented.

Transition paths in single-molecule force spectroscopy.

Science.gov (United States)

Cossio, Pilar; Hummer, Gerhard; Szabo, Attila

2018-03-28

In a typical single-molecule force spectroscopy experiment, the ends of the molecule of interest are connected by long polymer linkers to a pair of mesoscopic beads trapped in the focus of two laser beams. At constant force load, the total extension, i.e., the end-to-end distance of the molecule plus linkers, is measured as a function of time. In the simplest systems, the measured extension fluctuates about two values characteristic of folded and unfolded states, with occasional transitions between them. We have recently shown that molecular (un)folding rates can be recovered from such trajectories, with a small linker correction, as long as the characteristic time of the bead fluctuations is shorter than the residence time in the unfolded (folded) state. Here, we show that accurate measurements of the molecular transition path times require an even faster apparatus response. Transition paths, the trajectory segments in which the molecule (un)folds, are properly resolved only if the beads fluctuate more rapidly than the end-to-end distance of the molecule. Therefore, over a wide regime, the measured rates may be meaningful but not the transition path times. Analytic expressions for the measured mean transition path times are obtained for systems diffusing anisotropically on a two-dimensional free energy surface. The transition path times depend on the properties both of the molecule and of the pulling device.

Distance Between the Malleoli and the GroundA New Clinical Method to Measure Leg-Length Discrepancy.

Science.gov (United States)

Aguilar, Estela Gomez; Domínguez, Águeda Gómez; Peña-Algaba, Carolina; Castillo-López, José M

2017-03-01

The aim of this work is to introduce a useful method for the clinical diagnosis of leg-length inequality: distance between the malleoli and the ground (DMG). A transversal observational study was performed on 17 patients with leg-length discrepancy. Leg-length inequality was determined with different clinical methods: with a tape measure in a supine position from the anterior superior iliac spine (ASIS) to the internal and external malleoli, as the difference between the iliac crests when standing (pelvimeter), and as asymmetry between ASISs (PALpation Meter [PALM]; A&D Medical Products Healthcare, San Jose, California). The Foot Posture Index (FPI) and the navicular drop test were also used. The DMG with Perthes rule (perpendicular to the foot when standing), the distance between the internal malleolus and the ground (DIMG), and the distance between the external malleolus and the ground were designed by the authors. The DIMG is directly related to the traditional ASIS-external malleolus measurement (P = .003), the FPI (P = .010), and the navicular drop test (P DMG) is useful for diagnosing leg-length discrepancy and is related to the ASIS-external malleolus measurement. The DIMG is significantly inversely proportional to the degree of pronation according to the FPI. Conversely, determination of leg-length discrepancy with a tape measure from the ASIS to the malleoli cannot be performed interchangeably at the level of the internal or external malleolus.

Functional connectivity and structural covariance between regions of interest can be measured more accurately using multivariate distance correlation.

Science.gov (United States)

Geerligs, Linda; Cam-Can; Henson, Richard N

2016-07-15

Studies of brain-wide functional connectivity or structural covariance typically use measures like the Pearson correlation coefficient, applied to data that have been averaged across voxels within regions of interest (ROIs). However, averaging across voxels may result in biased connectivity estimates when there is inhomogeneity within those ROIs, e.g., sub-regions that exhibit different patterns of functional connectivity or structural covariance. Here, we propose a new measure based on "distance correlation"; a test of multivariate dependence of high dimensional vectors, which allows for both linear and non-linear dependencies. We used simulations to show how distance correlation out-performs Pearson correlation in the face of inhomogeneous ROIs. To evaluate this new measure on real data, we use resting-state fMRI scans and T1 structural scans from 2 sessions on each of 214 participants from the Cambridge Centre for Ageing & Neuroscience (Cam-CAN) project. Pearson correlation and distance correlation showed similar average connectivity patterns, for both functional connectivity and structural covariance. Nevertheless, distance correlation was shown to be 1) more reliable across sessions, 2) more similar across participants, and 3) more robust to different sets of ROIs. Moreover, we found that the similarity between functional connectivity and structural covariance estimates was higher for distance correlation compared to Pearson correlation. We also explored the relative effects of different preprocessing options and motion artefacts on functional connectivity. Because distance correlation is easy to implement and fast to compute, it is a promising alternative to Pearson correlations for investigating ROI-based brain-wide connectivity patterns, for functional as well as structural data. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Long-distance measurement-device-independent quantum key distribution with coherent-state superpositions.

Science.gov (United States)

Yin, H-L; Cao, W-F; Fu, Y; Tang, Y-L; Liu, Y; Chen, T-Y; Chen, Z-B

2014-09-15

Measurement-device-independent quantum key distribution (MDI-QKD) with decoy-state method is believed to be securely applied to defeat various hacking attacks in practical quantum key distribution systems. Recently, the coherent-state superpositions (CSS) have emerged as an alternative to single-photon qubits for quantum information processing and metrology. Here, in this Letter, CSS are exploited as the source in MDI-QKD. We present an analytical method that gives two tight formulas to estimate the lower bound of yield and the upper bound of bit error rate. We exploit the standard statistical analysis and Chernoff bound to perform the parameter estimation. Chernoff bound can provide good bounds in the long-distance MDI-QKD. Our results show that with CSS, both the security transmission distance and secure key rate are significantly improved compared with those of the weak coherent states in the finite-data case.

Extended VIKOR Method for Intuitionistic Fuzzy Multiattribute Decision-Making Based on a New Distance Measure

Directory of Open Access Journals (Sweden)

Xiao Luo

2017-01-01

Full Text Available An intuitionistic fuzzy VIKOR (IF-VIKOR method is proposed based on a new distance measure considering the waver of intuitionistic fuzzy information. The method aggregates all individual decision-makers’ assessment information based on intuitionistic fuzzy weighted averaging operator (IFWA, determines the weights of decision-makers and attributes objectively using intuitionistic fuzzy entropy, calculates the group utility and individual regret by the new distance measure, and then reaches a compromise solution. It can be effectively applied to multiattribute decision-making (MADM problems where the weights of decision-makers and attributes are completely unknown and the attribute values are intuitionistic fuzzy numbers (IFNs. The validity and stability of this method are verified by example analysis and sensitivity analysis, and its superiority is illustrated by the comparison with the existing method.

Poster - 35: Monitoring patient positioning during deep inspiration breath hold with a distance measuring laser

International Nuclear Information System (INIS)

Weston, Mark; Juhasz, Janos

2016-01-01

Purpose: The accuracy of treatment delivery for left breast/chest wall patients using deep inspiration breath hold (DIBH) is being monitored using a distance measuring laser (DML) Methods: A commercially available DML (DLS-C15, Dimetix) was mounted behind a Varian TrilogyTM linac. Relative to the machine isocenter, the laser from the beam was offset by 8 cm to the left and by 1 cm in the superior direction. This position was selected because this point is situated on the sternum for the majority of the left breast/chest-wall patients treated at our institution. The Varian Real-Time Positioning Management™ (RPM) guided DIBH treatments at our institution is delivered by placing the system’s tracking block on the patient’s abdomen. The treatment beam is enabled only when the block is in between a predefined abdomen motion range as determined during the CT simulation process. A LabVIEW program was developed to record both beam status (i.e. on/off) and distance measurements. In this study the DML was only used to monitor the position of a single point on the chest and no clinical decisions/adjustments were made based on these measurements. Results and Conclusions: Thus far, 34 fractions have been recorded for 4 patients. As such, the performance of our DIBH treatment technique cannot be fairly evaluated at this point. However, deviations between expected and measured distances have been observed and if these are found to be reproducible, then modifications in our treatment procedures and policies will have to take place.

Poster - 35: Monitoring patient positioning during deep inspiration breath hold with a distance measuring laser

Energy Technology Data Exchange (ETDEWEB)

Weston, Mark; Juhasz, Janos [Juravinski Cancer Centre (Canada)

2016-08-15

Purpose: The accuracy of treatment delivery for left breast/chest wall patients using deep inspiration breath hold (DIBH) is being monitored using a distance measuring laser (DML) Methods: A commercially available DML (DLS-C15, Dimetix) was mounted behind a Varian TrilogyTM linac. Relative to the machine isocenter, the laser from the beam was offset by 8 cm to the left and by 1 cm in the superior direction. This position was selected because this point is situated on the sternum for the majority of the left breast/chest-wall patients treated at our institution. The Varian Real-Time Positioning Management™ (RPM) guided DIBH treatments at our institution is delivered by placing the system’s tracking block on the patient’s abdomen. The treatment beam is enabled only when the block is in between a predefined abdomen motion range as determined during the CT simulation process. A LabVIEW program was developed to record both beam status (i.e. on/off) and distance measurements. In this study the DML was only used to monitor the position of a single point on the chest and no clinical decisions/adjustments were made based on these measurements. Results and Conclusions: Thus far, 34 fractions have been recorded for 4 patients. As such, the performance of our DIBH treatment technique cannot be fairly evaluated at this point. However, deviations between expected and measured distances have been observed and if these are found to be reproducible, then modifications in our treatment procedures and policies will have to take place.

Dependence of the polar Kerr angle and coercivity on repeat distance in sequentially prepared Tb/FeCo films

International Nuclear Information System (INIS)

Shin, S.

1991-01-01

Multilayer thin films of Tb and FeCo were prepared by sequential thermal evaporation of Tb and Fe 90 Co 10 alloy on glass substrates at ambient temperature in a vacuum of about 1 x 10 -6 Torr. The repeat distance of the films was varied from 3.5 to 175 A while maintaining the composition constant for all samples. Low-angle x-ray diffraction and Auger electron spectroscopy showed that a multilayer structure was achieved for films fabricated with a repeat distance Λ≥31.5 A. The polar Kerr rotation angle and coercivity of the samples were obtained by measuring the polar Kerr hysteresis loop using a 632.8-nm HeNe laser. It was observed that for the samples having a multilayer structure, the remnant Kerr angle and coercivity monotonically decreased with increasing repeat distance, and eventually disappeared for Λ≥70 A. For the samples showing a nonmultilayer structure, the remnant Kerr angle was independent of repeat distance. However, the coercivity increased with repeat distance until a broad maximum was obtained around Λ congruent 14--21 A

Interferometric 30 m bench for calibrations of 1D scales and optical distance measuring instruments

International Nuclear Information System (INIS)

Unkuri, J; Rantanen, A; Manninen, J; Esala, V-P; Lassila, A

2012-01-01

During construction of a new metrology building for MIKES, a 30 m interferometric bench was designed. The objective was to implement a straight, stable, adjustable and multifunctional 30 m measuring bench for calibrations. Special attention was paid to eliminating the effects of thermal expansion and inevitable concrete shrinkage. The linear guide, situated on top of a monolithic concrete beam, comprises two parallel round shafts with adjustable fixtures every 1 m. A carriage is moved along the rail and its position is followed by a reference interferometer. Depending on the measurement task, one or two retro-reflectors are fixed on the carriage. A microscope with a CCD camera and a monitor can be used to detect line mark positions on different line standards. When calibrating optical distance measuring instruments, various targets can be fixed to the carriage. For the most accurate measurements an online Abbe-error correction based on simultaneous carriage pitch measurement by a separate laser interferometer is applied. The bench is used for calibrations of machinist scales, tapes, circometers, electronic distance meters, total stations and laser trackers. The estimated expanded uncertainty for 30 m displacement for highest accuracy calibrations is 2.6 µm. (paper)

Distance covariance for stochastic processes

DEFF Research Database (Denmark)

Matsui, Muneya; Mikosch, Thomas Valentin; Samorodnitsky, Gennady

2017-01-01

The distance covariance of two random vectors is a measure of their dependence. The empirical distance covariance and correlation can be used as statistical tools for testing whether two random vectors are independent. We propose an analog of the distance covariance for two stochastic processes...

Shell-Tunneling Spectroscopy of the Single-Particle Energy Levels of Insulating Quantum Dots

NARCIS (Netherlands)

Bakkers, E.P.A.M.; Hens, Z.; Zunger, A.; Franceschetti, A; Kouwenhoven, L.P.; Gurevich, L.; Vanmaekelbergh, D.

2001-01-01

The energy levels of CdSe quantum dots are studied by scanning tunneling spectroscopy. By varying the tip-dot distance, we switch from "shell-filling" spectroscopy (where electrons accumulate in the dot and experience mutual repulsion) to "shell-tunneling" spectroscopy (where electrons tunnel, one

On the importance of the distance measures used to train and test knowledge-based potentials for proteins

DEFF Research Database (Denmark)

Carlsen, Martin; Koehl, Patrice; Røgen, Peter

2014-01-01

(PPD), while the other had the set of all distances filtered to reflect consistency in an ensemble of decoys (PPE). We tested four types of metric to characterize the distance between the decoy and the native structure, two based on extrinsic geometry (RMSD and GTD-TS*), and two based on intrinsic...... geometry (Q* and MT). The corresponding eight potentials were tested on a large collection of decoy sets. We found that it is usually better to train a potential using an intrinsic distance measure. We also found that PPE outperforms PPD, emphasizing the benefits of capturing consistent information...

Association between light absorption measurements of PM2.5 and distance from heavy traffic roads in the Mexico City metropolitan area.

Science.gov (United States)

Cortez-Lugo, Marlene; Escamilla-Núñez, Consuelo; Barraza-Villarreal, Albino; Texcalac-Sangrador, José Luis; Chow, Judith; Watson, John; Hernández-Cadena, Leticia; Romieu, Isabelle

2013-04-01

To study the relationship between light absorption measurements of PM2.5 at various distances from heavy traffic roads and diesel vehicle counts in Mexico City. PM2.5 samples were obtained from June 2003-June 2005 in three MCMA regions. Light absorption (b abs) in a subset of PM2.5 samples was determined. We evaluated the effect of distance and diesel vehicle counts to heavy traffic roads on PM2.5 b abs using generalized estimating equation models. Median PM2.5 b abs measurements significantly decrease as distance from heavy traffic roads increases (proads. Our model predicts that PM2.5 b abs measurements would increase by 20% (CI95% 3-38) as the hourly heavy diesel vehicle count increases by 150 per hour. PM2.5 b abs measurements are significantly associated with distance from motorways and traffic density and therefore can be used to assess human exposure to traffic-related emissions.

Ultrasound measurement of rotator cuff thickness and acromio-humeral distance in the diagnosis of subacromial impingement syndrome of the shoulder.

Science.gov (United States)

Cholewinski, Jerzy J; Kusz, Damian J; Wojciechowski, Piotr; Cielinski, Lukasz S; Zoladz, Miroslaw P

2008-04-01

The usefulness of ultrasound measurements in the diagnosis of the subacromial impingement syndrome of the shoulder was evaluated. Fifty-seven patients with unilateral symptoms of the impingement syndrome underwent ultrasound examination of both shoulder joints, which included assessment of rotator cuff integrity, measurement of rotator cuff thickness and the distance between the infero-lateral edge of acromion and the apex of the greater tuberosity of humerus (AGT distance) in the standard ultrasonographic positions. As a control group, 36 volunteers (72 shoulders) with no history of shoulder pain were examined sonographically. Ultrasonographic assessment of humeral head elevation, measured as the AGT distance, proved to be useful in establishing the diagnosis of the subacromial impingement syndrome of the shoulder. A difference in rotator cuff thickness of more than 1.1 mm and a difference in the AGT distance of more than 2.1 mm between both shoulder joints may reflect dysfunction of rotator cuff muscles.

Cross-population validation of statistical distance as a measure of physiological dysregulation during aging.

Science.gov (United States)

Cohen, Alan A; Milot, Emmanuel; Li, Qing; Legault, Véronique; Fried, Linda P; Ferrucci, Luigi

2014-09-01

Measuring physiological dysregulation during aging could be a key tool both to understand underlying aging mechanisms and to predict clinical outcomes in patients. However, most existing indices are either circular or hard to interpret biologically. Recently, we showed that statistical distance of 14 common blood biomarkers (a measure of how strange an individual's biomarker profile is) was associated with age and mortality in the WHAS II data set, validating its use as a measure of physiological dysregulation. Here, we extend the analyses to other data sets (WHAS I and InCHIANTI) to assess the stability of the measure across populations. We found that the statistical criteria used to determine the original 14 biomarkers produced diverging results across populations; in other words, had we started with a different data set, we would have chosen a different set of markers. Nonetheless, the same 14 markers (or the subset of 12 available for InCHIANTI) produced highly similar predictions of age and mortality. We include analyses of all combinatorial subsets of the markers and show that results do not depend much on biomarker choice or data set, but that more markers produce a stronger signal. We conclude that statistical distance as a measure of physiological dysregulation is stable across populations in Europe and North America. Copyright © 2014 Elsevier Inc. All rights reserved.

Measuring the Earth System in a Time of Global Environmental Change with Image Spectroscopy

Science.gov (United States)

Green, Robert O.

2005-01-01

Measuring the Earth system in a time of global environmental change. Imaging Spectroscopy enables remote measurement. Remote Measurement determination of the properties of the Earth's surface and atmosphere through the physics, chemistry and biology of the interaction of electromagnetic energy with matter.

Representing distance, consuming distance

DEFF Research Database (Denmark)

Larsen, Gunvor Riber

Title: Representing Distance, Consuming Distance Abstract: Distance is a condition for corporeal and virtual mobilities, for desired and actual travel, but yet it has received relatively little attention as a theoretical entity in its own right. Understandings of and assumptions about distance...... are being consumed in the contemporary society, in the same way as places, media, cultures and status are being consumed (Urry 1995, Featherstone 2007). An exploration of distance and its representations through contemporary consumption theory could expose what role distance plays in forming...

Fundamental tests and measures of the structure of matter at short distances

International Nuclear Information System (INIS)

Brodsky, S.J.

1981-07-01

Recent progress in gauge field theories has led to a new perspective on the structure of matter and basic interactions at short distances. It is clear that at very high energies quantum electrodynamics, together with the weak and strong interactions, are part of a unified theory with new fundamental constants, new symmetries, and new conservation laws. A non-technical introduction to these topics is given, with emphasis on fundamental tests and measurements. 21 references

Agreement between intraoperative measurements and optical coherence tomography of the limbus-insertion distance of the extraocular muscles.

Science.gov (United States)

de-Pablo-Gómez-de-Liaño, L; Fernández-Vigo, J I; Ventura-Abreu, N; Morales-Fernández, L; García-Feijóo, J; Gómez-de-Liaño, R

2016-12-01

To assess the agreement between intraoperative measurements of the limbus-insertion distance of the extraocular muscles with those measured by spectral domain optical coherence tomography. An analysis was made of a total of 67 muscles of 21 patients with strabismus. The limbus-insertion distance of the horizontal rectus muscles were measured using pre-operative SD-OCT and intra-operatively in 2 ways: 1) direct, after a conjunctival dissection in patients who underwent surgery, or 2) transconjunctival in patients who were treated with botulinum toxin, or in those who were not going to be operated. The intraclass correlation coefficient and Bland-Altman plots were calculated to determine the concordance between the 2 methods. The mean age was 45.9 ±20.9 years (range 16 to 85), with 52% being women. The percentage of identification by direct intraoperative measurement was 95.6% (22/23), by transconjunctival intraoperative measurement 90.9% (40/44), and by OCT 85% (57/67), with 22 muscles finally being analysed for the agreement study between direct intraoperative measurement and OCT measurements, and 35 muscles for the agreement between transconjuctival intraoperative measurement and OCT. The intraclass correlation coefficient showed good agreement with OCT and direct intraoperative measurements (0.931; 95% confidence interval (95% CI): 0.839-0.972; P<.001), and with transconjunctival intraoperative measurements (0.889; 95% CI: 0.790-0.942; P<.001). The SD-OCT is an effective technique to measure the distance from the insertion of the horizontal rectus muscles to the limbus, with a high agreement with intraoperative measurements being demonstrated. Copyright © 2016 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

Optical spectroscopy using gas-phase femtosecond laser filamentation.

Science.gov (United States)

Odhner, Johanan; Levis, Robert

2014-01-01

Femtosecond laser filamentation occurs as a dynamic balance between the self-focusing and plasma defocusing of a laser pulse to produce ultrashort radiation as brief as a few optical cycles. This unique source has many properties that make it attractive as a nonlinear optical tool for spectroscopy, such as propagation at high intensities over extended distances, self-shortening, white-light generation, and the formation of an underdense plasma. The plasma channel that constitutes a single filament and whose position in space can be controlled by its input parameters can span meters-long distances, whereas multifilamentation of a laser beam can be sustained up to hundreds of meters in the atmosphere. In this review, we briefly summarize the current understanding and use of laser filaments for spectroscopic investigations of molecules. A theoretical framework of filamentation is presented, along with recent experimental evidence supporting the established understanding of filamentation. Investigations carried out on vibrational and rotational spectroscopy, filament-induced breakdown, fluorescence spectroscopy, and backward lasing are discussed.

Measurement of electron paramagnetic resonance using terahertz time-domain spectroscopy.

Science.gov (United States)

Kozuki, Kohei; Nagashima, Takeshi; Hangyo, Masanori

2011-12-05

We present a frequency-domain electron spin resonance (ESR) measurement system using terahertz time-domain spectroscopy. A crossed polarizer technique is utilized to increase the sensitivity in detecting weak ESR signals of paramagnets caused by magnetic dipole transitions between magnetic sublevels. We demonstrate the measurements of ESR signal of paramagnetic copper(II) sulfate pentahydrate with uniaxial anisotropy of the g-factor under magnetic fields up to 10 T. The lineshape of the obtained ESR signals agrees well with the theoretical predictions for a powder sample with the uniaxial anisotropy.

Characterization of Nuclear Materials Using Complex of Non-Destructive and Mass-Spectroscopy Methods of Measurements

International Nuclear Information System (INIS)

Gorbunova, A.; Kramchaninov, A.

2015-01-01

Information and Analytical Centre for nuclear materials investigations was established in Russian Federation in the February 2 of 2009 by ROSATOM State Atomic Energy Corporation (the order #80). Its purpose is in preventing unauthorized access to nuclear materials and excluding their illicit traffic. Information and Analytical Centre includes analytical laboratory to provide composition and properties of nuclear materials of unknown origin for their identification. According to Regulation the Centre deals with: · identification of nuclear materials of unknown origin to provide information about their composition and properties; · arbitration analyzes of nuclear materials; · comprehensive research of nuclear and radioactive materials for developing techniques characterization of materials; · interlaboratory measurements; · measurements for control and accounting; · confirmatory measurements. Complex of non-destructive and mass-spectroscopy techniques was developed for the measurements. The complex consists of: · gamma-ray techniques on the base of MGAU, MGA and FRAM codes for uranium and plutonium isotopic composition; · gravimetrical technique with gamma-spectroscopy in addition for uranium content; · calorimetric technique for plutonium mass; · neutron multiplicity technique for plutonium mass; · measurement technique on the base of mass-spectroscopy for uranium isotopic composition; · measurement technique on the base of mass-spectroscopy for metallic impurities. Complex satisfies the state regulation requirements of ensuring the uniformity of measurements including the Russian Federation Federal Law on Ensuring the Uniformity of Measurements #102-FZ, Interstate Standard GOST R ISO/IEC 17025-2006, National Standards of Russian Federation GOST R 8.563-2009, GOST R 8.703-2010, Federal Regulations NRB-99/2009, OSPORB 99/2010. Created complex is provided in reference materials, equipment end certificated techniques. The complex is included in accredited

Effect of interelectrode distance on dc magnetron current-pressure characteristics

Science.gov (United States)

Mankelevich, Yu A.; Pal, A. F.; Ryabinkin, A. N.; Serov, A. O.

2018-01-01

The current-pressure (I-P) non-monotonic characteristic in the magnetron discharge dc in argon at different interelectrode distances was investigated. The ion spatial distribution was obtained with optical emission spectroscopy and the characteristic dimensions of the discharge structure in near cathode region were determined. It is shown that decreasing the distance between electrodes does not affect the shape and position of the nonmonotonic part of I-P characteristic until this distance become comparable with the dimensions of the ionization region near cathode. The existence of non-monotonic part of I-P characteristic is determined by the processes in the near cathode region and is probably unrelated with the cold electron transfer in the rest of the plasma.

Measurement of magnetic field gradients using Raman spectroscopy in a fountain

Science.gov (United States)

Srinivasan, Arvind; Zimmermann, Matthias; Efremov, Maxim A.; Davis, Jon P.; Narducci, Frank A.

2017-02-01

In many experiments involving cold atoms, it is crucial to know the strength of the magnetic field and/or the magnetic field gradient at the precise location of a measurement. While auxiliary sensors can provide some of this information, the sensors are usually not perfectly co-located with the atoms and so can only provide an approximation to the magnetic field strength. In this article, we describe a technique to measure the magnetic field, based on Raman spectroscopy, using the same atomic fountain source that will be used in future magnetically sensitive measurements.

Measuring distance through dense weighted networks: The case of hospital-associated pathogens.

Directory of Open Access Journals (Sweden)

Tjibbe Donker

2017-08-01

Full Text Available Hospital networks, formed by patients visiting multiple hospitals, affect the spread of hospital-associated infections, resulting in differences in risks for hospitals depending on their network position. These networks are increasingly used to inform strategies to prevent and control the spread of hospital-associated pathogens. However, many studies only consider patients that are received directly from the initial hospital, without considering the effect of indirect trajectories through the network. We determine the optimal way to measure the distance between hospitals within the network, by reconstructing the English hospital network based on shared patients in 2014-2015, and simulating the spread of a hospital-associated pathogen between hospitals, taking into consideration that each intermediate hospital conveys a delay in the further spread of the pathogen. While the risk of transferring a hospital-associated pathogen between directly neighbouring hospitals is a direct reflection of the number of shared patients, the distance between two hospitals far-away in the network is determined largely by the number of intermediate hospitals in the network. Because the network is dense, most long distance transmission chains in fact involve only few intermediate steps, spreading along the many weak links. The dense connectivity of hospital networks, together with a strong regional structure, causes hospital-associated pathogens to spread from the initial outbreak in a two-step process: first, the directly surrounding hospitals are affected through the strong connections, second all other hospitals receive introductions through the multitude of weaker links. Although the strong connections matter for local spread, weak links in the network can offer ideal routes for hospital-associated pathogens to travel further faster. This hold important implications for infection prevention and control efforts: if a local outbreak is not controlled in time

The distances of the Galactic Novae

Science.gov (United States)

Ozdonmez, Aykut; Guver, Tolga; Cabrera-Lavers, Antonio; Ak, Tansel

2016-07-01

Using location of the RC stars on the CMDs obtained from the UKIDSS, VISTA and 2MASS photometry, we have derived the reddening-distance relations towards each Galactic nova for which at least one independent reddening measurement exists. We were able to determine the distances of 72 Galactic novae and set lower limits on the distances of 45 systems. The reddening curves of the systems are presented. These curves can be also used to estimate reddening or the distance of any source, whose location is close to the position of the nova in our sample. The distance measurement method in our study can be easily applicable to any source, especially for ones that concentrated along the Galactic plane.

Holdup Measures on an SRNL Mossbauer Spectroscopy Instrument

Energy Technology Data Exchange (ETDEWEB)

Dewberry, R.; Brown, T.; Salaymeh, S.

2010-05-05

Gamma-ray holdup measurements of a Mossbauer spectroscopy instrument are described and modeled. In the qualitative acquisitions obtained in a low background area of Savannah River National Laboratory, only Am-241 and Np-237 activity were observed. The Am-241 was known to be the instrumental activation source, while the Np-237 is clearly observed as a source of contamination internal to the instrument. The two sources of activity are modeled separately in two acquisition configurations using two separate modeling tools. The results agree well, demonstrating a content of (1980 {+-} 150) {mu}Ci Am-241 and (110 {+-} 50) {mu}Ci of Np-237.

Heterodyne laser Doppler distance sensor with phase coding measuring stationary as well as laterally and axially moving objects

International Nuclear Information System (INIS)

Pfister, T; Günther, P; Nöthen, M; Czarske, J

2010-01-01

Both in production engineering and process control, multidirectional displacements, deformations and vibrations of moving or rotating components have to be measured dynamically, contactlessly and with high precision. Optical sensors would be predestined for this task, but their measurement rate is often fundamentally limited. Furthermore, almost all conventional sensors measure only one measurand, i.e. either out-of-plane or in-plane distance or velocity. To solve this problem, we present a novel phase coded heterodyne laser Doppler distance sensor (PH-LDDS), which is able to determine out-of-plane (axial) position and in-plane (lateral) velocity of rough solid-state objects simultaneously and independently with a single sensor. Due to the applied heterodyne technique, stationary or purely axially moving objects can also be measured. In addition, it is shown theoretically as well as experimentally that this sensor offers concurrently high temporal resolution and high position resolution since its position uncertainty is in principle independent of the lateral object velocity in contrast to conventional distance sensors. This is a unique feature of the PH-LDDS enabling precise and dynamic position and shape measurements also of fast moving objects. With an optimized sensor setup, an average position resolution of 240 nm was obtained

Tracking frequency laser distance gauge

International Nuclear Information System (INIS)

Phillips, J.D.; Reasenberg, R.D.

2005-01-01

Advanced astronomical missions with greatly enhanced resolution and physics missions of unprecedented accuracy will require laser distance gauges of substantially improved performance. We describe a laser gauge, based on Pound-Drever-Hall locking, in which the optical frequency is adjusted to maintain an interferometer's null condition. This technique has been demonstrated with pm performance. Automatic fringe hopping allows it to track arbitrary distance changes. The instrument is intrinsically free of the nm-scale cyclic bias present in traditional (heterodyne) high-precision laser gauges. The output is a radio frequency, readily measured to sufficient accuracy. The laser gauge has operated in a resonant cavity, which improves precision, can suppress the effects of misalignments, and makes possible precise automatic alignment. The measurement of absolute distance requires little or no additional hardware, and has also been demonstrated. The proof-of-concept version, based on a stabilized HeNe laser and operating on a 0.5 m path, has achieved 10 pm precision with 0.1 s integration time, and 0.1 mm absolute distance accuracy. This version has also followed substantial distance changes as fast as 16 mm/s. We show that, if the precision in optical frequency is a fixed fraction of the linewidth, both incremental and absolute distance precision are independent of the distance measured. We discuss systematic error sources, and present plans for a new version of the gauge based on semiconductor lasers and fiber-coupled components

Measurements of anterior chamber depth, white-to-white distance, anterior chamber angle, and pupil diameter using two Scheimpflug imaging devices

Directory of Open Access Journals (Sweden)

Alberto Domínguez-Vicent

2014-08-01

Full Text Available Purpose: To compare the ocular anterior chamber depth, white-to-white distance, anterior chamber angle, and pupil diameter, as measured with two different Scheimpflug imaging devices. Methods: This transversal study included 80 right eyes from 80 subjects aged from 20 to 40 years. Their spherical equivalents ranged from -4.25 to +1.00 diopters (D. Each eye's anterior chamber depth, white-to-white distance, anterior chamber angle, and pupil diameter, were measured for far vision using both the Galilei G4 (double Scheimpflug camera and the Pentacam HR (single Scheimpflug camera systems. Results: Mean anterior chamber depths were calculated as 3.12 ± 0.23 mm and 3.19 ± 0.24 mm when measured with the Galilei G4 and the Pentacam HR, respectively. The mean white-to-white distance measured was 11.84 ± 0.31 mm and 11.90 ± 0.43 mm when measured with the Galilei G4 and the Pentacam HR, respectively. Mean pupil diameters were measured as 3.22 ± 0.58 mm and 3.22 ± 0.52 mm when measured with the Galilei G4 and the Pentacam HR, respectively. Finally, the mean anterior chamber angle was 34.30 ± 2.86 degrees when it was measured with the Galilei G4, and 39.26 ± 2.85 degrees when measured with the Pentacam HR. A comparative analysis revealed that the Galilei G4 yielded a significantly lower (P0.05 for both devices were obtained for the white-to-white distance measurements. Conclusion: The Galilei G4 and Pentacam HR Scheimpflug systems cannot be used interchangeably because they produce significant measurement differences.

Measurement of plutonium isotopic composition by gamma-ray spectroscopy

International Nuclear Information System (INIS)

Kim, J. S.; Shin, J. S.; Ahn, J. S.

1998-01-01

The technology of the analysis of plutonium isotopic ratio is independent of the measurement geometry and applicable to samples of physical and chemical composition. Three standard plutonium samples were measured in the HPGe system. The results showed that CRM 136 and CRM 137 containing 238 Pu(0.223%) and 238 Pu(0.268%) were 18.4% and 14.2% error and CRM 138 of 238 Pu(0.01%) was 76% error. However the analysis represented less than 1.6% and 9% error in the three standard samples of highly involved 239 Pu and 240 Pu. Therefore, gamma-ray spectroscopy is very effective in the plutonium isotope analysis, having greater than 10% in content

Measuring protein dynamics with ultrafast two-dimensional infrared spectroscopy

International Nuclear Information System (INIS)

Adamczyk, Katrin; Candelaresi, Marco; Hunt, Neil T; Robb, Kirsty; Hoskisson, Paul A; Tucker, Nicholas P; Gumiero, Andrea; Walsh, Martin A; Parker, Anthony W

2012-01-01

Recent advances in the methodology and application of ultrafast two-dimensional infrared (2D-IR) spectroscopy to biomolecular systems are reviewed. A description of the 2D-IR technique and the molecular contributions to the observed spectra are presented followed by a discussion of recent literature relating to the use of 2D-IR and associated approaches for measuring protein dynamics. In particular, these include the use of diatomic ligand groups for measuring haem protein dynamics, isotopic labelling strategies and the use of vibrational probe groups. The final section reports on the current state of the art regarding the use of 2D-IR methods to provide insights into biological reaction mechanisms. (topical review)

Reliability of reference distances used in photogrammetry.

Science.gov (United States)

Aksu, Muge; Kaya, Demet; Kocadereli, Ilken

2010-07-01

To determine the reliability of the reference distances used for photogrammetric assessment. The sample consisted of 100 subjects with mean ages of 22.97 +/- 2.98 years. Five lateral and four frontal parameters were measured directly on the subjects' faces. For photogrammetric assessment, two reference distances for the profile view and three reference distances for the frontal view were established. Standardized photographs were taken and all the parameters that had been measured directly on the face were measured on the photographs. The reliability of the reference distances was checked by comparing direct and indirect values of the parameters obtained from the subjects' faces and photographs. Repeated measure analysis of variance (ANOVA) and Bland-Altman analyses were used for statistical assessment. For profile measurements, the indirect values measured were statistically different from the direct values except for Sn-Sto in male subjects and Prn-Sn and Sn-Sto in female subjects. The indirect values of Prn-Sn and Sn-Sto were reliable in both sexes. The poorest results were obtained in the indirect values of the N-Sn parameter for female subjects and the Sn-Me parameter for male subjects according to the Sa-Sba reference distance. For frontal measurements, the indirect values were statistically different from the direct values in both sexes except for one in male subjects. The indirect values measured were not statistically different from the direct values for Go-Go. The indirect values of Ch-Ch were reliable in male subjects. The poorest results were obtained according to the P-P reference distance. For profile assessment, the T-Ex reference distance was reliable for Prn-Sn and Sn-Sto in both sexes. For frontal assessment, Ex-Ex and En-En reference distances were reliable for Ch-Ch in male subjects.

Axial segregation in high intensity discharge lamps measured by laser absorption spectroscopy

NARCIS (Netherlands)

Stoffels, W.W.; Flikweert, A.J.; Nimalasuriya, T.; Groothuis, C.H.J.M.; Haverlag, M.; Kroesen, G.M.W.

2005-01-01

HID lamps containing rare earth additives (in our case dysprosium) show color separation because of axial segregation, caused by diffusion and convection. Two-dimensional atomic Dy density profiles are measured by means of laser absorption spectroscopy. The radially resolved atomic density

Scanning, non-contact, hybrid broadband diffuse optical spectroscopy and diffuse correlation spectroscopy system.

Science.gov (United States)

Johansson, Johannes D; Mireles, Miguel; Morales-Dalmau, Jordi; Farzam, Parisa; Martínez-Lozano, Mar; Casanovas, Oriol; Durduran, Turgut

2016-02-01

A scanning system for small animal imaging using non-contact, hybrid broadband diffuse optical spectroscopy (ncDOS) and diffuse correlation spectroscopy (ncDCS) is presented. The ncDOS uses a two-dimensional spectrophotometer retrieving broadband (610-900 nm) spectral information from up to fifty-seven source-detector distances between 2 and 5 mm. The ncDCS data is simultaneously acquired from four source-detector pairs. The sample is scanned in two dimensions while tracking variations in height. The system has been validated with liquid phantoms, demonstrated in vivo on a human fingertip during an arm cuff occlusion and on a group of mice with xenoimplanted renal cell carcinoma.

Measuring the e-Learning Autonomy of Distance Education Students

Directory of Open Access Journals (Sweden)

Mehmet Firat

2016-08-01

Full Text Available Previous studies have provided evidence that learner autonomy is an important factor in academic achievement. However, few studies have investigated the autonomy of distance education students in e-learning environments. The purpose of this study is to evaluate the e-learning autonomy of distance education students who are responsible for their own learning. For this purpose, as the first step of the study, an e-learning autonomy scale was developed. Analyses of the validity and reliability of the scale were carried out with the participation of 1,152 distance education students from Anadolu University, Open Education System. The scale has an internal consistency coefficient of α = 0.952 and a single factorial model that explains 66.58% of the total variance. The scale was implemented with 3,293 students from 42 different programs. According to the findings, student autonomy in e-learning environments is directly proportional to level of ICT use but not affected by program or gender.

Independent component analysis classification of laser induced breakdown spectroscopy spectra

International Nuclear Information System (INIS)

Forni, Olivier; Maurice, Sylvestre; Gasnault, Olivier; Wiens, Roger C.; Cousin, Agnès; Clegg, Samuel M.; Sirven, Jean-Baptiste; Lasue, Jérémie

2013-01-01

The ChemCam instrument on board Mars Science Laboratory (MSL) rover uses the laser-induced breakdown spectroscopy (LIBS) technique to remotely analyze Martian rocks. It retrieves spectra up to a distance of seven meters to quantify and to quantitatively analyze the sampled rocks. Like any field application, on-site measurements by LIBS are altered by diverse matrix effects which induce signal variations that are specific to the nature of the sample. Qualitative aspects remain to be studied, particularly LIBS sample identification to determine which samples are of interest for further analysis by ChemCam and other rover instruments. This can be performed with the help of different chemometric methods that model the spectra variance in order to identify a the rock from its spectrum. In this paper we test independent components analysis (ICA) rock classification by remote LIBS. We show that using measures of distance in ICA space, namely the Manhattan and the Mahalanobis distance, we can efficiently classify spectra of an unknown rock. The Mahalanobis distance gives overall better performances and is easier to manage than the Manhattan distance for which the determination of the cut-off distance is not easy. However these two techniques are complementary and their analytical performances will improve with time during MSL operations as the quantity of available Martian spectra will grow. The analysis accuracy and performances will benefit from a combination of the two approaches. - Highlights: • We use a novel independent component analysis method to classify LIBS spectra. • We demonstrate the usefulness of ICA. • We report the performances of the ICA classification. • We compare it to other classical classification schemes

The Distance to Nova V959 Mon from VLA Imaging

Science.gov (United States)

Linford, J. D.; Ribeiro, V. A. R. M.; Chomiuk, L.; Nelson, T.; Sokoloski, J. L.; Rupen, M. P.; Mukai, K.; O'Brien, T. J.; Mioduszewski, A. J.; Weston, J.

2015-06-01

Determining reliable distances to classical novae is a challenging but crucial step in deriving their ejected masses and explosion energetics. Here we combine radio expansion measurements from the Karl G. Jansky Very Large Array with velocities derived from optical spectra to estimate an expansion parallax for nova V959 Mon, the first nova discovered through its γ-ray emission. We spatially resolve the nova at frequencies of 4.5-36.5 GHz in nine different imaging epochs. The first five epochs cover the expansion of the ejecta from 2012 October to 2013 January, while the final four epochs span 2014 February-May. These observations correspond to days 126 through 199 and days 615 through 703 after the first detection of the nova. The images clearly show a non-spherical ejecta geometry. Utilizing ejecta velocities derived from three-dimensional modeling of optical spectroscopy, the radio expansion implies a distance between 0.9 ± 0.2 and 2.2 ± 0.4 kpc, with a most probable distance of 1.4 ± 0.4 kpc. This distance implies a γ-ray luminosity of 0.6× {{10}35} erg s-1, which is much less than the prototype γ-ray-detected nova, V407 Cyg, possibly due to the lack of a red giant companion in the V959 Mon system. V959 Mon also has a much lower γ-ray luminosity than other classical novae detected in γ-rays to date, indicating a range of at least a factor of 10 in the γ-ray luminosities for these explosions.

Repeated stimulation, inter-stimulus interval and inter-electrode distance alters muscle contractile properties as measured by Tensiomyography

Science.gov (United States)

Johnson, Mark I.; Francis, Peter

2018-01-01

Context The influence of methodological parameters on the measurement of muscle contractile properties using Tensiomyography (TMG) has not been published. Objective To investigate the; (1) reliability of stimulus amplitude needed to elicit maximum muscle displacement (Dm), (2) effect of changing inter-stimulus interval on Dm (using a fixed stimulus amplitude) and contraction time (Tc), (3) the effect of changing inter-electrode distance on Dm and Tc. Design Within subject, repeated measures. Participants 10 participants for each objective. Main outcome measures Dm and Tc of the rectus femoris, measured using TMG. Results The coefficient of variance (CV) and the intra-class correlation (ICC) of stimulus amplitude needed to elicit maximum Dm was 5.7% and 0.92 respectively. Dm was higher when using an inter-electrode distance of 7cm compared to 5cm [P = 0.03] and when using an inter-stimulus interval of 10s compared to 30s [P = 0.017]. Further analysis of inter-stimulus interval data, found that during 10 repeated stimuli Tc became faster after the 5th measure when compared to the second measure [P<0.05]. The 30s inter-stimulus interval produced the most stable Tc over 10 measures compared to 10s and 5s respectively. Conclusion Our data suggest that the stimulus amplitude producing maximum Dm of the rectus femoris is reliable. Inter-electrode distance and inter-stimulus interval can significantly influence Dm and/ or Tc. Our results support the use of a 30s inter-stimulus interval over 10s or 5s. Future studies should determine the influence of methodological parameters on muscle contractile properties in a range of muscles. PMID:29451885

Plutonium isotopic measurements by gamma-ray spectroscopy

International Nuclear Information System (INIS)

Haas, F.X.; Lemming, J.F.

1976-01-01

A nondestructive technique is described for calculating plutonium-238, plutonium-240, plutonium-241 and americium-241 relative to plutonium-239 from measured peak areas in the high resolution gamma-ray spectra of solid plutonium samples. Gamma-ray attenuation effects were minimized by selecting sets of neighboring peaks in the spectrum whose components are due to the different isotopes. Since the detector efficiencies are approximately the same for adjacent peaks, the accuracy of the isotopic ratios is dependent on the half-lives, branching intensities, and measured peak areas. The data presented describe the results obtained by analyzing gamma-ray spectra in the energy region from 120 to 700 keV. Most of the data analyzed were obtained from plutonium material containing 6 percent plutonium-240. Sample weights varied from 0.25 g to approximately 1.2 kg. The methods were also applied to plutonium samples containing up to 23 percent plutonium-240 with weights of 0.25 to 200 g. Results obtained by gamma-ray spectroscopy are compared to chemical analyses of aliquots taken from the bulk samples

Application of discriminant analysis and generalized distance measures to uranium exploration

International Nuclear Information System (INIS)

Beauchamp, J.J.; Begovich, C.L.; Kane, V.E.; Wolf, D.A.

1979-10-01

The National Uranium Resource Evaluation (NURE) Project has as its goal estimation of the nation's uranium resources. It is possible to use discriminant analysis methods on hydrogeochemical data collected in the NURE Program to aid in formulating geochemical models which can be used to identify the anomalous regions necessary for resource estimation. Discriminant analysis methods have been applied to data from the Plainview, Texas Quadrangle which has approximately 850 groundwater samples with more than 40 quantitative measurements per sample. Discriminant analysis topics involving estimation of misclassification probabilities, variable selection, and robust discrimination are applied. A method using generalized distance measures is given which enables assigning samples to a background population or a mineralized population whose parameters were estimated from separate studies. Each topic is related to its relevance in identifying areas of possible interest to uranium exploration

Technique for long and absolute distance measurement based on laser pulse repetition frequency sweeping

Science.gov (United States)

Castro Alves, D.; Abreu, Manuel; Cabral, A.; Jost, Michael; Rebordão, J. M.

2017-11-01

In this work we present a technique to perform long and absolute distance measurements based on mode-locked diode lasers. Using a Michelson interferometer, it is possible to produce an optical cross-correlation between laser pulses of the reference arm with the pulses from the measurement arm, adjusting externally their degree of overlap either changing the pulse repetition frequency (PRF) or the position of the reference arm mirror for two (or more) fixed frequencies. The correlation of the travelling pulses for precision distance measurements relies on ultra-short pulse durations, as the uncertainty associated to the method is dependent on the laser pulse width as well as on a highly stable PRF. Mode-locked Diode lasers are a very appealing technology for its inherent characteristics, associated to compactness, size and efficiency, constituting a positive trade-off with regard to other mode-locked laser sources. Nevertheless, main current drawback is the non-availability of frequency-stable laser diodes. The laser used is a monolithic mode-locked semiconductor quantum-dot (QD) laser. The laser PRF is locked to an external stabilized RF reference. In this work we will present some of the preliminary results and discuss the importance of the requirements related to laser PRF stability in the final metrology system accuracy.

NOTE ON TRAVEL TIME SHIFTS DUE TO AMPLITUDE MODULATION IN TIME-DISTANCE HELIOSEISMOLOGY MEASUREMENTS

International Nuclear Information System (INIS)

Nigam, R.; Kosovichev, A. G.

2010-01-01

Correct interpretation of acoustic travel times measured by time-distance helioseismology is essential to get an accurate understanding of the solar properties that are inferred from them. It has long been observed that sunspots suppress p-mode amplitude, but its implications on travel times have not been fully investigated so far. It has been found in test measurements using a 'masking' procedure, in which the solar Doppler signal in a localized quiet region of the Sun is artificially suppressed by a spatial function, and using numerical simulations that the amplitude modulations in combination with the phase-speed filtering may cause systematic shifts of acoustic travel times. To understand the properties of this procedure, we derive an analytical expression for the cross-covariance of a signal that has been modulated locally by a spatial function that has azimuthal symmetry and then filtered by a phase-speed filter typically used in time-distance helioseismology. Comparing this expression to the Gabor wavelet fitting formula without this effect, we find that there is a shift in the travel times that is introduced by the amplitude modulation. The analytical model presented in this paper can be useful also for interpretation of travel time measurements for the non-uniform distribution of oscillation amplitude due to observational effects.

Relative distance between tracers as a measure of diffusivity within moving aggregates

Science.gov (United States)

Pönisch, Wolfram; Zaburdaev, Vasily

2018-02-01

Tracking of particles, be it a passive tracer or an actively moving bacterium in the growing bacterial colony, is a powerful technique to probe the physical properties of the environment of the particles. One of the most common measures of particle motion driven by fluctuations and random forces is its diffusivity, which is routinely obtained by measuring the mean squared displacement of the particles. However, often the tracer particles may be moving in a domain or an aggregate which itself experiences some regular or random motion and thus masks the diffusivity of tracers. Here we provide a method for assessing the diffusivity of tracer particles within mobile aggregates by measuring the so-called mean squared relative distance (MSRD) between two tracers. We provide analytical expressions for both the ensemble and time averaged MSRD allowing for direct identification of diffusivities from experimental data.

Accuracy Improvement of Discharge Measurement with Modification of Distance Made Good Heading

Directory of Open Access Journals (Sweden)

Jongkook Lee

2016-01-01

Full Text Available Remote control boats equipped with an Acoustic Doppler Current Profiler (ADCP are widely accepted and have been welcomed by many hydrologists for water discharge, velocity profile, and bathymetry measurements. The advantages of this technique include high productivity, fast measurements, operator safety, and high accuracy. However, there are concerns about controlling and operating a remote boat to achieve measurement goals, especially during extreme events such as floods. When performing river discharge measurements, the main error source stems from the boat path. Due to the rapid flow in a flood condition, the boat path is not regular and this can cause errors in discharge measurements. Therefore, improvement of discharge measurements requires modification of boat path. As a result, the measurement errors in flood flow conditions are 12.3–21.8% before the modification of boat path, but 1.2–3.7% after the DMG modification of boat path. And it is considered that the modified discharges are very close to the observed discharge in the flood flow conditions. In this study, through the distance made good (DMG modification of the boat path, a comprehensive discharge measurement with high accuracy can be achieved.

Extraction of Poloidal Velocity from Charge Exchange Recombination Spectroscopy Measurements

International Nuclear Information System (INIS)

Solomon, W.M.; Burrell, K.H.; Gohil, P.; Groebner, R.J.; Baylor, L.R.

2004-01-01

A novel approach has been implemented on DIII-D to allow the correct determination of the plasma poloidal velocity from charge exchange spectroscopy measurements. Unlike usual techniques, the need for detailed atomic physics calculations to properly interpret the results is alleviated. Instead, the needed atomic physics corrections are self-consistently determined directly from the measurements, by making use of specially chosen viewing chords. Modeling results are presented that were used to determine a set of views capable of measuring the correction terms. We present the analysis of a quiescent H-mode discharge, illustrating that significant modifications to the velocity profiles are required in these high ion temperature conditions. We also present preliminary measurements providing the first direct comparison of the standard cross-section correction to the atomic physics calculations

Accurate measurements of E2 lifetimes using the coincidence recoil-distance method

International Nuclear Information System (INIS)

Bhalla, R.K.; Poletti, A.R.

1984-01-01

Mean lives of four E2 transitions in the (2s, 1d) shell have been measured using the recoil-distance method (RDM). γ-rays de-exciting the level of interest were detected in coincidence with particles detected in an annular detector at a backward angle thereby reducing the background and producing a beam of recoiling nuclei of well-defined energy and recoil direction. Lifetimes measured were: 22 Ne, 1.275 MeV level (2 + -> 0 + ), 5.16 +- 0.13 ps; 26 Mg, 3.588 MeV level (0 + -> 2 + ), 9.29 +- 0.23 ps; 30 Si, 3.788 MeV level (0 + -> 2 + ), 12.00 +- 0.70 ps; 38 Ar, 3.377 MeV level (0 + -> 2 + ), 34.5 +- 1.5 ps. The present measurements are compared to those of previous investigators. For the 22 Ne level, averaged results from four different measurement techniques are compared and found to be in good agreement. The experimental results are compared to shell-model calculations. (orig.)

Rapid measurement of meat spoilage using fluorescence spectroscopy

Science.gov (United States)

Wu, Binlin; Dahlberg, Kevin; Gao, Xin; Smith, Jason; Bailin, Jacob

2017-02-01

Food spoilage is mainly caused by microorganisms, such as bacteria. In this study, we measure the autofluorescence in meat samples longitudinally over a week in an attempt to develop a method to rapidly detect meat spoilage using fluorescence spectroscopy. Meat food is a biological tissue, which contains intrinsic fluorophores, such as tryptophan, collagen, nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) etc. As meat spoils, it undergoes various morphological and chemical changes. The concentrations of the native fluorophores present in a sample may change. In particular, the changes in NADH and FAD are associated with microbial metabolism, which is the most important process of the bacteria in food spoilage. Such changes may be revealed by fluorescence spectroscopy and used to indicate the status of meat spoilage. Therefore, such native fluorophores may be unique, reliable and nonsubjective indicators for detection of spoiled meat. The results of the study show that the relative concentrations of all above fluorophores change as the meat samples kept in room temperature ( 19° C) spoil. The changes become more rapidly after about two days. For the meat samples kept in a freezer ( -12° C), the changes are much less or even unnoticeable over a-week-long storage.

Optical spectroscopy of laser-produced plasmas for standoff isotopic analysis

Science.gov (United States)

Harilal, S. S.; Brumfield, B. E.; LaHaye, N. L.; Hartig, K. C.; Phillips, M. C.

2018-06-01

lineshapes, as opposed to emission spectroscopy which requires higher plasma temperatures to be able to detect thermally excited emission. Improvements in laser and detection systems and spectroscopic techniques have allowed for isotopic measurements to be carried out at standoff distances under ambient atmospheric conditions, which have expanded the applicability of optical spectroscopy-based isotopic measurements to a variety of scientific fields. These technological advances offer an in-situ measurement capability that was previously not available. This review will focus on isotope detection through emission, absorption, and fluorescence spectroscopy of atoms and molecules in a laser-produced plasma formed from a solid sample. A description of the physics behind isotope shifts in atoms and molecules is presented, followed by the physics behind solid sampling of laser ablation plumes, optical methods for isotope measurements, the suitable physical conditions of laser-produced plasma plumes for isotopic analysis, and the current status. Finally, concluding remarks will be made on the existing knowledge/technological gaps identified from the current literature and suggestions for the future work.

DEPTH MEASUREMENT OF DISRUPTED LAYER ON SILICON WAFER SURFACE USING AUGER SPECTROSCOPY METHOD

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V. A. Solodukha

2016-01-01

Full Text Available The paper proposes a method for depth measurement of a disrupted layer on silicon wafer surface which is based on application of Auger spectroscopy with the precision sputtering of surface silicon layers and registration of the Auger electron yield intensity. In order to measure the disrupted layer with the help of Auger spectroscopy it is necessary to determine dependence of the released Auger electron amount on sputtering time (profile and then the dependence is analyzed. Silicon amount in the disrupted layer is less than in the volume. While going deeper the disruptive layer is decreasing that corresponds to an increase of atom density in a single layer. The essence of the method lies in the fact the disruptive layer is removed by ion beam sputtering and detection of interface region is carried out with the help of registration of the Auger electron yield intensity from the sputtered surface up to the moment when it reaches the value which is equal to the Auger electron yield intensity for single-crystal silicon. While removing surface silicon layers the registration of the Auger electron yield intensity from silicon surface makes it possible to control efficiently a presence of the disrupted layer on the silicon wafer surface. In this case depth control locality is about 1.0 nm due to some peculiarities of Auger spectroscopy method. The Auger electron yield intensity is determined automatically while using Auger spectrometer and while removing the disrupted layer the intensity is gradually increasing. Depth of the disrupted layer is determined by measuring height of the step which has been formed as a result of removal of the disrupted layer from the silicon wafer surface. Auger spectroscopy methods ensures an efficient depth control surface disruptions at the manufacturing stages of silicon wafers and integrated circuits. The depth measurement range of disruptions constitutes 0.001–1.000 um.

A pneumatic bellows-driven setup for controlled-distance electrochemical impedance measurements of Zircaloy-2 in simulated BWR conditions

International Nuclear Information System (INIS)

Arilahti, E.; Bojinov, M.; Hansson-Lyyra, L.

2004-01-01

This paper describes a novel pneumatic bellows-driven arrangement designed for controlled distance electrochemistry (CDE) measurements. The feasibility of the new arrangement has been verified by performing contact electric impedance measurements to study corrosion of Zircaloy-2 in a re-circulation loop simulating the BWR conditions. Until now, the measurements have been carried out using a step-motor driven controlled-distance electrochemistry (CDE) arrangement. The electrical and electrochemical properties of the pre transition oxide on Zircaloy-2 determined from these measurements were in good agreement with those estimated from measurements with a step-motor driven CDE. Furthermore, the results indicate that the bellows-driven CDE device is less sensitive to the contact pressure variation than the step-motor driven arrangement. This property combined with the bellows driven displacement mechanism provides a clear advantage for future in-core corrosion studies of fuel cladding materials. (Author)

Characterization of the spatial structure of local functional connectivity using multi-distance average correlation measures.

Science.gov (United States)

Macia, Didac; Pujol, Jesus; Blanco-Hinojo, Laura; Martínez-Vilavella, Gerard; Martín-Santos, Rocío; Deus, Joan

2018-04-24

There is ample evidence from basic research in neuroscience of the importance of local cortico-cortical networks. Millimetric resolution is achievable with current functional MRI (fMRI) scanners and sequences, and consequently a number of "local" activity similarity measures have been defined to describe patterns of segregation and integration at this spatial scale. We have introduced the use of Iso-Distant local Average Correlation (IDAC), easily defined as the average fMRI temporal correlation of a given voxel with other voxels placed at increasingly separated iso-distant intervals, to characterize the curve of local fMRI signal similarities. IDAC curves can be statistically compared using parametric multivariate statistics. Furthermore, by using RGB color-coding to display jointly IDAC values belonging to three different distance lags, IDAC curves can also be displayed as multi-distance IDAC maps. We applied IDAC analysis to a sample of 41 subjects scanned under two different conditions, a resting state and an auditory-visual continuous stimulation. Multi-distance IDAC mapping was able to discriminate between gross anatomo-functional cortical areas and, moreover, was sensitive to modulation between the two brain conditions in areas known to activate and de-activate during audio-visual tasks. Unlike previous fMRI local similarity measures already in use, our approach draws special attention to the continuous smooth pattern of local functional connectivity.

Nondestructive millimeter wave imaging and spectroscopy using dielectric focusing probes

International Nuclear Information System (INIS)

Hejase, Jose A.; Shane, Steven S.; Park, Kyoung Y.; Chahal, Premjeet

2014-01-01

A tool for interrogating objects over a wide band of frequencies with subwavelength resolution at small standoff distances (near field region) in the transmission mode using a single source and detector measurement setup in the millimeter wave band is presented. The design utilizes optics like principles for guiding electromagnetic millimeter waves from large cross-sectional areas to considerably smaller sub-wavelength areas. While plano-convex lenses can be used to focus waves to a fine resolution, they usually require a large stand-off distance thus resulting in alignment and spacing issues. The design procedure and simulation analysis of the focusing probes are presented in this study along with experimental verification of performance and imaging and spectroscopy examples. Nondestructive evaluation will find benefit from such an apparatus including biological tissue imaging, electronic package integrity testing, composite dielectric structure evaluation for defects and microfluidic sensing

Nondestructive millimeter wave imaging and spectroscopy using dielectric focusing probes

Energy Technology Data Exchange (ETDEWEB)

Hejase, Jose A.; Shane, Steven S.; Park, Kyoung Y.; Chahal, Premjeet [Terahertz Systems Laboratory (TeSLa) - Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48823 (United States)

2014-02-18

A tool for interrogating objects over a wide band of frequencies with subwavelength resolution at small standoff distances (near field region) in the transmission mode using a single source and detector measurement setup in the millimeter wave band is presented. The design utilizes optics like principles for guiding electromagnetic millimeter waves from large cross-sectional areas to considerably smaller sub-wavelength areas. While plano-convex lenses can be used to focus waves to a fine resolution, they usually require a large stand-off distance thus resulting in alignment and spacing issues. The design procedure and simulation analysis of the focusing probes are presented in this study along with experimental verification of performance and imaging and spectroscopy examples. Nondestructive evaluation will find benefit from such an apparatus including biological tissue imaging, electronic package integrity testing, composite dielectric structure evaluation for defects and microfluidic sensing.

Filament-induced remote surface ablation for long range laser-induced breakdown spectroscopy operation

International Nuclear Information System (INIS)

Rohwetter, Ph.; Stelmaszczyk, K.; Woeste, L.; Ackermann, R.; Mejean, G.; Salmon, E.; Kasparian, J.; Yu, J.; Wolf, J.-P.

2005-01-01

We demonstrate laser induced ablation and plasma line emission from a metallic target at distances up to 180 m from the laser, using filaments (self-guided propagation structures ∼ 100 μm in diameter and ∼ 5 x 10 13 W/cm 2 in intensity) appearing as femtosecond and terawatt laser pulses propagating in air. The remarkable property of filaments to propagate over a long distance independently of the diffraction limit opens the frontier to long range operation of the laser-induced breakdown spectroscopy technique. We call this special configuration of remote laser-induced breakdown spectroscopy 'remote filament-induced breakdown spectroscopy'. Our results show main features of filament-induced ablation on the surface of a metallic sample and associated plasma emission. Our experimental data allow us to estimate requirements for the detection system needed for kilometer-range remote filament-induced breakdown spectroscopy experiment

Repeated stimulation, inter-stimulus interval and inter-electrode distance alters muscle contractile properties as measured by Tensiomyography.

Directory of Open Access Journals (Sweden)

Hannah V Wilson

Full Text Available The influence of methodological parameters on the measurement of muscle contractile properties using Tensiomyography (TMG has not been published.To investigate the; (1 reliability of stimulus amplitude needed to elicit maximum muscle displacement (Dm, (2 effect of changing inter-stimulus interval on Dm (using a fixed stimulus amplitude and contraction time (Tc, (3 the effect of changing inter-electrode distance on Dm and Tc.Within subject, repeated measures.10 participants for each objective.Dm and Tc of the rectus femoris, measured using TMG.The coefficient of variance (CV and the intra-class correlation (ICC of stimulus amplitude needed to elicit maximum Dm was 5.7% and 0.92 respectively. Dm was higher when using an inter-electrode distance of 7cm compared to 5cm [P = 0.03] and when using an inter-stimulus interval of 10s compared to 30s [P = 0.017]. Further analysis of inter-stimulus interval data, found that during 10 repeated stimuli Tc became faster after the 5th measure when compared to the second measure [P<0.05]. The 30s inter-stimulus interval produced the most stable Tc over 10 measures compared to 10s and 5s respectively.Our data suggest that the stimulus amplitude producing maximum Dm of the rectus femoris is reliable. Inter-electrode distance and inter-stimulus interval can significantly influence Dm and/ or Tc. Our results support the use of a 30s inter-stimulus interval over 10s or 5s. Future studies should determine the influence of methodological parameters on muscle contractile properties in a range of muscles.

Research on in-situ measurement technique of three-dimensional distance

International Nuclear Information System (INIS)

Shiraishi, Masatake; Aoshima, Shinichi; Aose, Shinichi; Takeuchi, Masayuki

2004-04-01

Equipments used in the nuclear facility must be done the adequate maintenance and should be exchanged to new ones by the remote control. For this aim, we need information about the objects such as a distance, a profile, and an inclination with the required accuracy. The aim of this research is, thus, to establish and equipment exchanging method by controlling the position of equipments and parts. In order to catch the whole position condition of objects, a rough measurement system was developed, and information was obtained from the front side of parts. Then, a precise measurement system that performs local measurement was constructed to obtain the information around the shade portion of the objects, which is not obtainable by the rough measurement system. Therefore, the new system performs two measurements: a rough measurement and a precise measurement. Consequently, it was found to be effective for acquiring a lot of information that are not obtained only by the rough measurement system form the front side only. Before exchanging equipments, we need to know their conditions whether they are still applicable or not. The another point of this research is, therefore, to develop an on-line deterioration diagnosis method of equipments. Specifically, a new approach in which the laser light is projected onto the equipment surface is proposed to check the contrast of the reflection pattern. Because the contrast is corresponding to the condition of the measured surface and therefore we can conjecture the surface states of the object surface by obtaining the contrast. We examined those states empirically by changing the laser angle of incidence and the receiving angle of camera. As a result, the validity of the on-line diagnosis was confirmed through various experiments. Finally, the possibility of applying VR method was discussed as a control of robot manipulator, although this research is on going. (author)

Surface enhanced infrared spectroscopy using interacting gold nanowires

Energy Technology Data Exchange (ETDEWEB)

Neubrech, Frank; Weber, Daniel; Pucci, Annemarie [Kirchhoff-Institut fuer Physik, Heidelberg (Germany); Shen, Hong [Universite Troyes, Troyes (France); Lamy de la Chapelle, Marc [Universite Paris 13, Bobigny (France)

2009-07-01

We performed surface enhanced infrared spectroscopy (SEIRS) of molecules adsorbed on gold nanowires using synchrotron light of the ANKA IR-beamline at the Forschungszentrum Karlsruhe (Germany). Arrays of gold nanowires with interparticle spacings down to 30nm were prepared by electron beam lithography. The interparticle distance was reduced further by wet-chemically increasing the size of the gold nanowires. The growth of the wires was proofed using IR spectroscopy as well as scanning electron microscopy. After this preparation step, appropriate arrays of nanowires with an interparticle distance down to a few nanometers were selected to demonstrate the surface enhanced infrared spectroscopy of one monolayer octadecanthiol (ODT). As know from SEIRS studies using single gold nanowires, the spectral position of the antenna-like resonance in relation to the absorption bands of ODT (2850cm-1 and 2919cm-1) is crucial for both, the lineshape of the molecular vibration and the signal enhancement. In contrast to single nanowires studies, a further increase of the enhanced signals is expected due to the interaction of the electromagnetic fields of the close-by nanowires.

Distance and protective barrier effects on the composite resin degree of conversion

Science.gov (United States)

Coutinho, Margareth; Trevizam, Natália Carvalho; Takayassu, Renata Nakase; Leme, Ariene Arcas; Soares, Giulliana Panfiglio

2013-01-01

Context: The food wrap films are used to cover the tip of curing light units in order to avoid contamination and prevent damage to the light guide. However, their effects on resin polymerization are not fully known. Aims: We investigated the effects on restoration efficiency of a food wrap protective barrier used on the tip of curing light units. Materials and Methods: For each treatment, five replications were performed, a total of 60 bovine incisor. The degree of conversion (%DC) of restorations with the composite resin Opallis EA2 was evaluated using 3 curing light devices (Optilux 501, Optilight and Ultra LED) and 2 curing distances (0 and 5 mm). The composite resin was tested for restoration of cavities in bovine crowns. %DC values were measured by the Fourier transform infrared spectroscopy-attenuated total reflectance technique. Statistical Analysis Used: The data were analyzed using 3-way ANOVA and Tukey's test. Results: Use of the protective film lowered %DC (F = 4.13; P = 0.05), and the effects of curing distance were associated to the curing light device (F = 3.61; P = 0.03). Conclusions: The distance from the light curing tip and use of a translucent protective barrier on the light-cure device can both impair composite resin %DC. PMID:24015001

Hierarchical traits distances explain grassland Fabaceae species' ecological niches distances

Science.gov (United States)

Fort, Florian; Jouany, Claire; Cruz, Pablo

2015-01-01

Fabaceae species play a key role in ecosystem functioning through their capacity to fix atmospheric nitrogen via their symbiosis with Rhizobium bacteria. To increase benefits of using Fabaceae in agricultural systems, it is necessary to find ways to evaluate species or genotypes having potential adaptations to sub-optimal growth conditions. We evaluated the relevance of phylogenetic distance, absolute trait distance and hierarchical trait distance for comparing the adaptation of 13 grassland Fabaceae species to different habitats, i.e., ecological niches. We measured a wide range of functional traits (root traits, leaf traits, and whole plant traits) in these species. Species phylogenetic and ecological distances were assessed from a species-level phylogenetic tree and species' ecological indicator values, respectively. We demonstrated that differences in ecological niches between grassland Fabaceae species were related more to their hierarchical trait distances than to their phylogenetic distances. We showed that grassland Fabaceae functional traits tend to converge among species with the same ecological requirements. Species with acquisitive root strategies (thin roots, shallow root systems) are competitive species adapted to non-stressful meadows, while conservative ones (coarse roots, deep root systems) are able to tolerate stressful continental climates. In contrast, acquisitive species appeared to be able to tolerate low soil-P availability, while conservative ones need high P availability. Finally we highlight that traits converge along the ecological gradient, providing the assumption that species with similar root-trait values are better able to coexist, regardless of their phylogenetic distance. PMID:25741353

Hierarchical traits distances explain grassland Fabaceae species’ ecological niches distances

Directory of Open Access Journals (Sweden)

Florian eFort

2015-02-01

Full Text Available Fabaceae species play a key role in ecosystem functioning through their capacity to fix atmospheric nitrogen via their symbiosis with Rhizobium bacteria. To increase benefits of using Fabaceae in agricultural systems, it is necessary to find ways to evaluate species or genotypes having potential adaptations to sub-optimal growth conditions. We evaluated the relevance of phylogenetic distance, absolute trait distance and hierarchical trait distance for comparing the adaptation of 13 grassland Fabaceae species to different habitats, i.e. ecological niches. We measured a wide range of functional traits (root traits, leaf traits and whole plant traits in these species. Species phylogenetic and ecological distances were assessed from a species-level phylogenetic tree and species’ ecological indicator values, respectively. We demonstrated that differences in ecological niches between grassland Fabaceae species were related more to their hierarchical trait distances than to their phylogenetic distances. We showed that grassland Fabaceae functional traits tend to converge among species with the same ecological requirements. Species with acquisitive root strategies (thin roots, shallow root systems are competitive species adapted to non-stressful meadows, while conservative ones (coarse roots, deep root systems are able to tolerate stressful continental climates. In contrast, acquisitive species appeared to be able to tolerate low soil-P availability, while conservative ones need high P availability. Finally we highlight that traits converge along the ecological gradient, providing the assumption that species with similar root-trait values are better able to coexist, regardless of their phylogenetic distance.

A Short-Range Distance Sensor with Exceptional Linearity

Science.gov (United States)

Simmons, Steven; Youngquist, Robert

2013-01-01

A sensor has been demonstrated that can measure distance over a total range of about 300 microns to an accuracy of about 0.1 nm (resolution of about 0.01 nm). This represents an exceptionally large dynamic range of operation - over 1,000,000. The sensor is optical in nature, and requires the attachment of a mirror to the object whose distance is being measured. This work resulted from actively developing a white light interferometric system to be used to measure the depths of defects in the Space Shuttle Orbiter windows. The concept was then applied to measuring distance. The concept later expanded to include spectrometer calibration. In summary, broadband (i.e., white) light is launched into a Michelson interferometer, one mirror of which is fixed and one of which is attached to the object whose distance is to be measured. The light emerging from the interferometer has traveled one of two distances: either the distance to the fixed mirror and back, or the distance to the moving mirror and back. These two light beams mix and produce an interference pattern where some wavelengths interfere constructively and some destructively. Sending this light into a spectrometer allows this interference pattern to be analyzed, yielding the net distance difference between the two paths. The unique feature of this distance sensor is its ability to measure accurately distance over a dynamic range of more than one million, the ratio of its range (about 300 microns) to its accuracy (about 0.1 nanometer). Such a large linear operating range is rare and arises here because both amplitude and phase-matching algorithms contribute to the performance. The sensor is limited by the need to attach a mirror of some kind to the object being tracked, and by the fairly small total range, but the exceptional dynamic range should make it of interest.

In-Plane Impedance Spectroscopy measurements in Vanadium Dioxide thin films

Science.gov (United States)

Ramirez, Juan; Patino, Edgar; Schmidt, Rainer; Sharoni, Amos; Gomez, Maria; Schuller, Ivan

2012-02-01

In plane Impedance Spectroscopy measurements have been done in Vanadium Dioxide thin films in the range of 100 Hz to 1 MHz. Our measurements allows distinguishing between the resistive and capacitive response of the Vanadium Dioxide films across the metal-insulator transition. A non ideal RC behavior was found in our thin films from room temperature up to 334 K. Around the MIT, an increase of the total capacitance is observed. A capacitor-network model is able to reproduce the capacitance changes across the MIT. Above the MIT, the system behaves like a metal as expected, and a modified equivalent circuit is necessary to describe the impedance data adequately.

The developmental trajectory of brain-scalp distance from birth through childhood: implications for functional neuroimaging.

Directory of Open Access Journals (Sweden)

Michael S Beauchamp

Full Text Available Measurements of human brain function in children are of increasing interest in cognitive neuroscience. Many techniques for brain mapping used in children, including functional near-infrared spectroscopy (fNIRS, electroencephalography (EEG, magnetoencephalography (MEG and transcranial magnetic stimulation (TMS, use probes placed on or near the scalp. The distance between the scalp and the brain is a key variable for these techniques because optical, electrical and magnetic signals are attenuated by distance. However, little is known about how scalp-brain distance differs between different cortical regions in children or how it changes with development. We investigated scalp-brain distance in 71 children, from newborn to age 12 years, using structural T1-weighted MRI scans of the whole head. Three-dimensional reconstructions were created from the scalp surface to allow for accurate calculation of brain-scalp distance. Nine brain landmarks in different cortical regions were manually selected in each subject based on the published fNIRS literature. Significant effects were found for age, cortical region and hemisphere. Brain-scalp distances were lowest in young children, and increased with age to up to double the newborn distance. There were also dramatic differences between brain regions, with up to 50% differences between landmarks. In frontal and temporal regions, scalp-brain distances were significantly greater in the right hemisphere than in the left hemisphere. The largest contributors to developmental changes in brain-scalp distance were increases in the corticospinal fluid (CSF and inner table of the cranium. These results have important implications for functional imaging studies of children: age and brain-region related differences in fNIRS signals could be due to the confounding factor of brain-scalp distance and not true differences in brain activity.

Prenatal Triclosan Exposure and Anthropometric Measures Including Anogenital Distance in Danish Infants

DEFF Research Database (Denmark)

Lassen, Tina Harmer; Frederiksen, Hanne; Kyhl, Henriette Boye

2016-01-01

, Swan SH, Main KM, Andersson AM, Lind DV, Husby S, Wohlfahrt-Veje C, Skakkebæk NE, Jensen TK. 2016. Prenatal triclosan exposure and anthropometric measures including anogenital distance in Danish infants. Environ Health Perspect 124:1261-1268; http://dx.doi.org/10.1289/ehp.1409637.......BACKGROUND: Triclosan (TCS) is widely used as an antibacterial agent in consumer products such as hand soap and toothpaste, and human exposure is widespread. TCS is suspected of having endocrine-disrupting properties, but few human studies have examined the developmental effects of prenatal TCS...

Static and Dynamic Measurement of Dopamine Adsorption in Carbon Fiber Microelectrodes Using Electrochemical Impedance Spectroscopy.

Science.gov (United States)

Rivera-Serrano, Nilka; Pagan, Miraida; Colón-Rodríguez, Joanisse; Fuster, Christian; Vélez, Román; Almodovar-Faria, Jose; Jiménez-Rivera, Carlos; Cunci, Lisandro

2018-02-06

In this study, electrochemical impedance spectroscopy was used for the first time to study the adsorption of dopamine in carbon fiber microelectrodes. In order to show a proof-of-concept, static and dynamic measurements were taken at potentials ranging from -0.4 to 0.8 V versus Ag|AgCl to demonstrate the versatility of this technique to study dopamine without the need of its oxidation. We used electrochemical impedance spectroscopy and single frequency electrochemical impedance to measure different concentrations of dopamine as low as 1 nM. Moreover, the capacitance of the microelectrodes surface was found to decrease due to dopamine adsorption, which is dependent on its concentration. The effect of dissolved oxygen and electrochemical oxidation of the surface in the detection of dopamine was also studied. Nonoxidized and oxidized carbon fiber microelectrodes were prepared and characterized by optical microscopy, scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. Optimum working parameters of the electrodes, such as frequency and voltage, were obtained for better measurement. Electrochemical impedance of dopamine was determined at different concentration, voltages, and frequencies. Finally, dynamic experiments were conducted using a flow cell and single frequency impedance in order to study continuous and real-time measurements of dopamine.

Ethnical distance in Vojvodina: Research results

Directory of Open Access Journals (Sweden)

Lazar Žolt

2005-01-01

Full Text Available This article presents the results of the ethnical distance measuring in Vojvodina, the north Province of the Republic of Serbia. The measuring was carried out on autumn 2002, during realization of the wider project of multiculturalism research in the mentioned region. According to the results the ethnical distances in Vojvodina are quite equalized and they are grouped around the attitude "all the same". Vojvodinian Serbs are more favorable partners for the majority of social contacts, and the relatively largest distance is shown toward Roma. The ethnical distance results also discovers two very important factors for understanding the interethnic relations in Vojvodina: first, the "rational" kind of social contacts with the members of the other ethnical groups are more preferable for the majority of respondents, and second, they have very equal distances toward their own ethnical groups.

Atom spectroscopy

International Nuclear Information System (INIS)

Kodling, K.

1981-01-01

Experiments on atom photoabsorption spectroscopy using synchrotron radiation in the 10-1000 eV range are reviewed. Properties of the necessary synchrotron radiation and the experiment on absorption spectroscopy are briefly described. Comparison with other spectroscopy methods is conducted. Some data on measuring photoabsorption, photoelectron emission and atom mass spectra are presented [ru

[A method of temperature measurement for hot forging with surface oxide based on infrared spectroscopy].

Science.gov (United States)

Zhang, Yu-cun; Qi, Yan-de; Fu, Xian-bin

2012-05-01

High temperature large forging is covered with a thick oxide during forging. It leads to a big measurement data error. In this paper, a method of measuring temperature based on infrared spectroscopy is presented. It can effectively eliminate the influence of surface oxide on the measurement of temperature. The method can measure the surface temperature and emissivity of the oxide directly using the infrared spectrum. The infrared spectrum is radiated from surface oxide of forging. Then it can derive the real temperature of hot forging covered with the oxide using the heat exchange equation. In order to greatly restrain interference spectroscopy through included in the received infrared radiation spectrum, three interference filter system was proposed, and a group of optimal gap parameter values using spectral simulation were obtained. The precision of temperature measurement was improved. The experimental results show that the method can accurately measure the surface temperature of high temperature forging covered with oxide. It meets the requirements of measurement accuracy, and the temperature measurement method is feasible according to the experiment result.

A method for measurements of neutral fragments kinetic energies released to a specific dissociation threshold: optical translational spectroscopy

International Nuclear Information System (INIS)

Roney, A.; Frigon, C.; Larzilliere, M.

1999-01-01

The optical translational spectroscopy technique, based on the principles of fast ion beam laser spectroscopy (FIBLAS) and translational spectroscopy, allows the kinetic energies study of neutral fragments released through free dissociation of a neutral molecule. This method presents interesting features such as near-threshold energy measurements and selection of a specific dissociation limit. The fragments resulting from free dissociation (not induced) of neutral molecules, produced by charge exchange processes with a fast ion beam, are probed by laser radiation. Monitoring of the laser-induced fluorescence allows high-resolution spectra due to the kinematic compression of the velocity spread. Measurements of kinetic energies released to the second limit of dissociation H(1s) + H(2l) of H 2 are put forth and compared with those obtained by means of off-axis translational spectroscopy

Dielectric-spectroscopy approach to ferrofluid nanoparticle clustering induced by an external electric field.

Science.gov (United States)

Rajnak, Michal; Kurimsky, Juraj; Dolnik, Bystrik; Kopcansky, Peter; Tomasovicova, Natalia; Taculescu-Moaca, Elena Alina; Timko, Milan

2014-09-01

An experimental study of magnetic colloidal particles cluster formation induced by an external electric field in a ferrofluid based on transformer oil is presented. Using frequency domain isothermal dielectric spectroscopy, we study the influence of a test cell electrode separation distance on a low-frequency relaxation process. We consider the relaxation process to be associated with an electric double layer polarization taking place on the particle surface. It has been found that the relaxation maximum considerably shifts towards lower frequencies when conducting the measurements in the test cells with greater electrode separation distances. As the electric field intensity was always kept at a constant value, we propose that the particle cluster formation induced by the external ac electric field accounts for that phenomenon. The increase in the relaxation time is in accordance with the Schwarz theory of electric double layer polarization. In addition, we analyze the influence of a static electric field generated by dc bias voltage on a similar shift in the relaxation maximum position. The variation of the dc electric field for the hysteresis measurements purpose provides understanding of the development of the particle clusters and their decay. Following our results, we emphasize the utility of dielectric spectroscopy as a simple, complementary method for detection and study of clusters of colloidal particles induced by external electric field.

Alfalfa discovery of the nearby gas-rich dwarf galaxy Leo P. IV. Distance measurement from LBT optical imaging

Energy Technology Data Exchange (ETDEWEB)

McQuinn, Kristen B. W.; Skillman, Evan D.; Berg, Danielle [Minnesota Institute for Astrophysics, School of Physics and Astronomy, 116 Church Street, S.E., University of Minnesota, Minneapolis, MN 55455 (United States); Cannon, John M. [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); Salzer, John J.; Rhode, Katherine L. [Department of Astronomy, Indiana University, 727 East 3rd Street, Bloomington, IN 47405 (United States); Adams, Elizabeth A. K.; Giovanelli, Riccardo; Haynes, Martha P. [Center for Radiophysics and Space Research, Space Sciences Building, Cornell University, Ithaca, NY 14853 (United States); Dolphin, Andrew, E-mail: kmcquinn@astro.umn.edu, E-mail: skillman@astro.umn.edu, E-mail: berg@astro.umn.edu, E-mail: jcannon@macalester.edu, E-mail: rhode@astro.indiana.edu, E-mail: slaz@astro.indiana.edu, E-mail: betsey@astro.cornell.edu, E-mail: riccardo@astro.cornell.edu, E-mail: haynes@astro.cornell.edu [Raytheon Company, 1151 E. Hermans Road, Tucson, AZ 85756 (United States)

2013-12-01

Leo P is a low-luminosity dwarf galaxy discovered through the blind H I Arecibo Legacy Fast ALFA survey. The H I and follow-up optical observations have shown that Leo P is a gas-rich dwarf galaxy with both active star formation and an underlying older population, as well as an extremely low oxygen abundance. Here, we measure the distance to Leo P by applying the tip of the red giant branch (TRGB) distance method to photometry of the resolved stellar population from new Large Binocular Telescope V and I band imaging. We measure a distance modulus of 26.19{sub −0.50}{sup +0.17} mag corresponding to a distance of 1.72{sub −0.40}{sup +0.14} Mpc. Although our photometry reaches 3 mag below the TRGB, the sparseness of the red giant branch yields higher uncertainties on the lower limit of the distance. Leo P is outside the Local Group with a distance and velocity consistent with the local Hubble flow. While located in a very low-density environment, Leo P lies within ∼0.5 Mpc of a loose association of dwarf galaxies which include NGC 3109, Antlia, Sextans A, and Sextans B, and 1.1 Mpc away from its next nearest neighbor, Leo A. Leo P is one of the lowest metallicity star-forming galaxies known in the nearby universe, comparable in metallicity to I Zw 18 and DDO 68, but with stellar characteristics similar to dwarf spheriodals (dSphs) in the Local Volume such as Carina, Sextans, and Leo II. Given its physical properties and isolation, Leo P may provide an evolutionary link between gas-rich dwarf irregular galaxies and dSphs that have fallen into a Local Group environment and been stripped of their gas.

Accurate measurements of E2 lifetimes using the coincidence recoil-distance method

Science.gov (United States)

Bhalla, R. K.; Poletti, A. R.

1984-05-01

Mean lives of four E2 transitions in the (2s, 1d) shell have been measured using the recoil-distance method (RDM), γ-rays de-exciting the level of interest were detected in coincidence with particles detected in an annular detector at a backward angle thereby reducing the background and producing a beam of recoiling nuclei of well-defined energy and recoil direction. Lifetimes measured were: 22Ne, 1.275 MeV level (2 + → 0 +), 5.16±0.13 ps; 26Mg, 3.588 MeV level (0 + → 2 +), 9.29±0.23 ps; 30Si, 3.788 MeV level (0 +→ 2 +), 12.00±0.70 ps; 38Ar, 3.377 MeV level (0 + → 2 +), 34.5±1.5 ps. The present measurements are compared to those of previous investigators. For the 22Ne level, averaged results from four different measurement techniques are compared and found to be in good agreement. The experimental results are compared to shell-model calculations.

Electron momentum density measurements by means of positron annihilation and Compton spectroscopy

International Nuclear Information System (INIS)

Gerber, W.; Dlubek, G.; Marx, U.; Bruemmer, O.; Prautzsch, J.

1982-01-01

The electron momentum density is measured applying positron annihilation and Compton spectroscopy in order to get information about electron wave functions. Compton spectroscopic measurements of Pd-Ag and Cu-Zn alloy systems are carried out taking into account crystal structure, mixability, and order state. Three-dimensional momentum densities of silicon are determined in order to get better information about its electronic structure. The momentum density and the spin density of ferromagnetic nickel are investigated using angular correlation curves

Application of discriminant analysis and generalized distance measures to uranium exploration

International Nuclear Information System (INIS)

Beauchamp, J.J.; Begovich, C.L.; Kane, V.E.; Wolf, D.A.

1980-01-01

The National Uranium Resource Evaluation (NURE) Program has as its goal the estimation of the nation's uranium resources. It is possile to use discriminant analysis methods on hydrogeochemical data collected in the NURE Program to aid in fomulating geochemical models that can be used to identify the anomalous areas used in resource estimation. Discriminant' analysis methods have been applied to data from the Plainview, Texas Quadrangle which has approximately 850 groundwater samples with more than 40 quantitative measurements per sample. Discriminant analysis topics involving estimation of misclassification probabilities, variable selection, and robust discrimination are applied. A method using generalized distance measures is given which enables the assignment of samples to a background population or a mineralized population whose parameters were estimated from separate studies. Each topic is related to its relevance in identifying areas of possible interest to uranium exploration. However, the methodology presented here is applicable to the identification of regions associated with other types of resources. 8 figures, 3 tables

Novel nuclear laser spectroscopy method using superfluid helium for measurement of spins and moments of exotic nuclei

International Nuclear Information System (INIS)

Furukawa, Takeshi; Wakui, Takashi; Yang, Xiaofei; Fujita, Tomomi; Imamura, Kei; Yamaguchi, Yasuhiro; Tetsuka, Hiroki; Tsutsui, Yoshiki; Mitsuya, Yosuke; Ichikawa, Yuichi; Ishibashi, Yoko; Yoshida, Naoki; Shirai, Hazuki; Ebara, Yuta; Hayasaka, Miki; Arai, Shino; Muramoto, Sosuke

2013-01-01

Highlights: • Development of a novel nuclear laser spectroscopy method using superfluid helium. • Observation of the Zeeman resonance with the 85 Rb beam introduced into helium. • Demonstration of deducing the nuclear spins from the observed resonance spectrum. -- Abstract: We have been developing a novel nuclear laser spectroscopy method “OROCHI” for determining spins and moments of exotic radioisotopes. In this method, we use superfluid helium as a stopping material of energetic radioisotope beams and then stopped radioisotope atoms are subjected to in situ laser spectroscopy in superfluid helium. To confirm the feasibility of this method for rare radioisotopes, we carried out a test experiment using a 85 Rb beam. In this experiment, we have successfully measured the Zeeman resonance signals from the 85 Rb atoms stopped in superfluid helium by laser-RF double resonance spectroscopy. This method is efficient for the measurement of spins and moments of more exotic nuclei

Robustness of Distance-to-Default

DEFF Research Database (Denmark)

Jessen, Cathrine; Lando, David

2013-01-01

. A notable exception is a model with stochastic volatility of assets. In this case both the ranking of firms and the estimated default probabilities using distance-to-default perform significantly worse. We therefore propose a volatility adjustment of the distance-to-default measure, that significantly...

A tentative theory of large distance physics

International Nuclear Information System (INIS)

Friedan, Daniel

2003-01-01

A theoretical mechanism is devised to determine the large distance physics of spacetime. It is a two dimensional nonlinear model, the lambda model, set to govern the string world surface in an attempt to remedy the failure of string theory, as it stands. The lambda model is formulated to cancel the infrared divergent effects of handles at short distance on the world surface. The target manifold is the manifold of background spacetimes. The coupling strength is the spacetime coupling constant. The lambda model operates at 2d distance Δ -1 , very much shorter than the 2d distance μ -1 where the world surface is seen. A large characteristic spacetime distance L is given by L 2 ln(Δ/μ). Spacetime fields of wave number up to 1=L are the local coordinates for the manifold of spacetimes. The distribution of fluctuations at 2d distances shorter than Δ -1 gives the a priori measure on the target manifold, the manifold of spacetimes. If this measure concentrates at a macroscopic spacetime, then, nearby, it is a measure on the spacetime fields. The lambda model thereby constructs a spacetime quantum field theory, cutoff at ultraviolet distance L, describing physics at distances larger than L. The lambda model also constructs an effective string theory with infrared cutoff L, describing physics at distances smaller than L. The lambda model evolves outward from zero 2d distance, Δ -1 = 0, building spacetime physics starting from L ∞ and proceeding downward in L. L can be taken smaller than any distance practical for experiments, so the lambda model, if right, gives all actually observable physics. The harmonic surfaces in the manifold of spacetimes are expected to have novel nonperturbative effects at large distances. (author)

Haptic Discrimination of Distance

Science.gov (United States)

van Beek, Femke E.; Bergmann Tiest, Wouter M.; Kappers, Astrid M. L.

2014-01-01

While quite some research has focussed on the accuracy of haptic perception of distance, information on the precision of haptic perception of distance is still scarce, particularly regarding distances perceived by making arm movements. In this study, eight conditions were measured to answer four main questions, which are: what is the influence of reference distance, movement axis, perceptual mode (active or passive) and stimulus type on the precision of this kind of distance perception? A discrimination experiment was performed with twelve participants. The participants were presented with two distances, using either a haptic device or a real stimulus. Participants compared the distances by moving their hand from a start to an end position. They were then asked to judge which of the distances was the longer, from which the discrimination threshold was determined for each participant and condition. The precision was influenced by reference distance. No effect of movement axis was found. The precision was higher for active than for passive movements and it was a bit lower for real stimuli than for rendered stimuli, but it was not affected by adding cutaneous information. Overall, the Weber fraction for the active perception of a distance of 25 or 35 cm was about 11% for all cardinal axes. The recorded position data suggest that participants, in order to be able to judge which distance was the longer, tried to produce similar speed profiles in both movements. This knowledge could be useful in the design of haptic devices. PMID:25116638

Haptic discrimination of distance.

Directory of Open Access Journals (Sweden)

Femke E van Beek

Full Text Available While quite some research has focussed on the accuracy of haptic perception of distance, information on the precision of haptic perception of distance is still scarce, particularly regarding distances perceived by making arm movements. In this study, eight conditions were measured to answer four main questions, which are: what is the influence of reference distance, movement axis, perceptual mode (active or passive and stimulus type on the precision of this kind of distance perception? A discrimination experiment was performed with twelve participants. The participants were presented with two distances, using either a haptic device or a real stimulus. Participants compared the distances by moving their hand from a start to an end position. They were then asked to judge which of the distances was the longer, from which the discrimination threshold was determined for each participant and condition. The precision was influenced by reference distance. No effect of movement axis was found. The precision was higher for active than for passive movements and it was a bit lower for real stimuli than for rendered stimuli, but it was not affected by adding cutaneous information. Overall, the Weber fraction for the active perception of a distance of 25 or 35 cm was about 11% for all cardinal axes. The recorded position data suggest that participants, in order to be able to judge which distance was the longer, tried to produce similar speed profiles in both movements. This knowledge could be useful in the design of haptic devices.

In-beam measurement of the hydrogen hyperfine splitting and prospects for antihydrogen spectroscopy.

Science.gov (United States)

Diermaier, M; Jepsen, C B; Kolbinger, B; Malbrunot, C; Massiczek, O; Sauerzopf, C; Simon, M C; Zmeskal, J; Widmann, E

2017-06-12

Antihydrogen, the lightest atom consisting purely of antimatter, is an ideal laboratory to study the CPT symmetry by comparison with hydrogen. With respect to absolute precision, transitions within the ground-state hyperfine structure (GS-HFS) are most appealing by virtue of their small energy separation. ASACUSA proposed employing a beam of cold antihydrogen atoms in a Rabi-type experiment, to determine the GS-HFS in a field-free region. Here we present a measurement of the zero-field hydrogen GS-HFS using the spectroscopy apparatus of ASACUSA's antihydrogen experiment. The measured value of ν HF =1,420,405,748.4(3.4) (1.6) Hz with a relative precision of 2.7 × 10 -9 constitutes the most precise determination of this quantity in a beam and verifies the developed spectroscopy methods for the antihydrogen HFS experiment to the p.p.b. level. Together with the recently presented observation of antihydrogen atoms 2.7 m downstream of the production region, the prerequisites for a measurement with antihydrogen are now available within the ASACUSA collaboration.

Handwriting individualization using distance and rarity

Science.gov (United States)

Tang, Yi; Srihari, Sargur; Srinivasan, Harish

2012-01-01

Forensic individualization is the task of associating observed evidence with a specific source. The likelihood ratio (LR) is a quantitative measure that expresses the degree of uncertainty in individualization, where the numerator represents the likelihood that the evidence corresponds to the known and the denominator the likelihood that it does not correspond to the known. Since the number of parameters needed to compute the LR is exponential with the number of feature measurements, a commonly used simplification is the use of likelihoods based on distance (or similarity) given the two alternative hypotheses. This paper proposes an intermediate method which decomposes the LR as the product of two factors, one based on distance and the other on rarity. It was evaluated using a data set of handwriting samples, by determining whether two writing samples were written by the same/different writer(s). The accuracy of the distance and rarity method, as measured by error rates, is significantly better than the distance method.

Weighted Evidence Combination Rule Based on Evidence Distance and Uncertainty Measure: An Application in Fault Diagnosis

Directory of Open Access Journals (Sweden)

Lei Chen

2018-01-01

Full Text Available Conflict management in Dempster-Shafer theory (D-S theory is a hot topic in information fusion. In this paper, a novel weighted evidence combination rule based on evidence distance and uncertainty measure is proposed. The proposed approach consists of two steps. First, the weight is determined based on the evidence distance. Then, the weight value obtained in first step is modified by taking advantage of uncertainty. Our proposed method can efficiently handle high conflicting evidences with better performance of convergence. A numerical example and an application based on sensor fusion in fault diagnosis are given to demonstrate the efficiency of our proposed method.

Continuity Properties of Distances for Markov Processes

DEFF Research Database (Denmark)

Jaeger, Manfred; Mao, Hua; Larsen, Kim Guldstrand

2014-01-01

In this paper we investigate distance functions on finite state Markov processes that measure the behavioural similarity of non-bisimilar processes. We consider both probabilistic bisimilarity metrics, and trace-based distances derived from standard Lp and Kullback-Leibler distances. Two desirable...

Distance between images

Science.gov (United States)

Gualtieri, J. A.; Le Moigne, J.; Packer, C. V.

1992-01-01

Comparing two binary images and assigning a quantitative measure to this comparison finds its purpose in such tasks as image recognition, image compression, and image browsing. This quantitative measurement may be computed by utilizing the Hausdorff distance of the images represented as two-dimensional point sets. In this paper, we review two algorithms that have been proposed to compute this distance, and we present a parallel implementation of one of them on the MasPar parallel processor. We study their complexity and the results obtained by these algorithms for two different types of images: a set of displaced pairs of images of Gaussian densities, and a comparison of a Canny edge image with several edge images from a hierarchical region growing code.

I Agree to Sit Next to You. Does That Mean I Like You? Measuring Using the Wrong Tapeline--The Lack of 'Social Distance' Measures for Inclusive School Development and Research--A Review of the Literature

Science.gov (United States)

Gerullis, Anita; Huber, Christian

2018-01-01

This review provides an overview of definitions and measurements of 'Social Distance' and attitudes children without disabilities carry towards children with disabilities. Measures include explicit and implicit approaches but clearly, the 'Bogardus Social Distance Scale' ("A Social Distance Scale," 1933, 14 May 2014) is the most used…

Walking Behavior of Zoo Elephants: Associations between GPS-Measured Daily Walking Distances and Environmental Factors, Social Factors, and Welfare Indicators.

Directory of Open Access Journals (Sweden)

Matthew R Holdgate

Full Text Available Research with humans and other animals suggests that walking benefits physical health. Perhaps because these links have been demonstrated in other species, it has been suggested that walking is important to elephant welfare, and that zoo elephant exhibits should be designed to allow for more walking. Our study is the first to address this suggestion empirically by measuring the mean daily walking distance of elephants in North American zoos, determining the factors that are associated with variations in walking distance, and testing for associations between walking and welfare indicators. We used anklets equipped with GPS data loggers to measure outdoor daily walking distance in 56 adult female African (n = 33 and Asian (n = 23 elephants housed in 30 North American zoos. We collected 259 days of data and determined associations between distance walked and social, housing, management, and demographic factors. Elephants walked an average of 5.3 km/day with no significant difference between species. In our multivariable model, more diverse feeding regimens were correlated with increased walking, and elephants who were fed on a temporally unpredictable feeding schedule walked 1.29 km/day more than elephants fed on a predictable schedule. Distance walked was also positively correlated with an increase in the number of social groupings and negatively correlated with age. We found a small but significant negative correlation between distance walked and nighttime Space Experience, but no other associations between walking distances and exhibit size were found. Finally, distance walked was not related to health or behavioral outcomes including foot health, joint health, body condition, and the performance of stereotypic behavior, suggesting that more research is necessary to determine explicitly how differences in walking may impact elephant welfare.

Walking Behavior of Zoo Elephants: Associations between GPS-Measured Daily Walking Distances and Environmental Factors, Social Factors, and Welfare Indicators.

Science.gov (United States)

Holdgate, Matthew R; Meehan, Cheryl L; Hogan, Jennifer N; Miller, Lance J; Soltis, Joseph; Andrews, Jeff; Shepherdson, David J

2016-01-01

Research with humans and other animals suggests that walking benefits physical health. Perhaps because these links have been demonstrated in other species, it has been suggested that walking is important to elephant welfare, and that zoo elephant exhibits should be designed to allow for more walking. Our study is the first to address this suggestion empirically by measuring the mean daily walking distance of elephants in North American zoos, determining the factors that are associated with variations in walking distance, and testing for associations between walking and welfare indicators. We used anklets equipped with GPS data loggers to measure outdoor daily walking distance in 56 adult female African (n = 33) and Asian (n = 23) elephants housed in 30 North American zoos. We collected 259 days of data and determined associations between distance walked and social, housing, management, and demographic factors. Elephants walked an average of 5.3 km/day with no significant difference between species. In our multivariable model, more diverse feeding regimens were correlated with increased walking, and elephants who were fed on a temporally unpredictable feeding schedule walked 1.29 km/day more than elephants fed on a predictable schedule. Distance walked was also positively correlated with an increase in the number of social groupings and negatively correlated with age. We found a small but significant negative correlation between distance walked and nighttime Space Experience, but no other associations between walking distances and exhibit size were found. Finally, distance walked was not related to health or behavioral outcomes including foot health, joint health, body condition, and the performance of stereotypic behavior, suggesting that more research is necessary to determine explicitly how differences in walking may impact elephant welfare.

A study of the normal interpedicular distance of the spine in Korean teenagers (Estimation of normal range by roentgenographic measurement)

International Nuclear Information System (INIS)

Lee, Myung Uk

1979-01-01

The radiological measurement of the interpedicular disease using a routine antero-posterior view of the spine gives important clinical criteria in evaluation of the intraspinal tumor and stenosis of the spinal canal, and aids for diagnosis of the lesions. In 1934 Elsberg and Dyke reported values of interpedicular distance as determined on roentgenograms for spine of white adult, and in 1968 Song prepared normal values of interpedicular distance for Korean adult. The present investigation was undertaken to provide normal interpedicular distance of Korean teenagers. The author observed the antero-posterior films of the spine of 200 normal teenagers which were composed of 100 male and 100 female. The normal values of the interpedicular distance of Korean teenagers were obtained, as well as 90% tolerance range for clinical use. In this statistical analysis, there were noted significant differences between male and female, and each age groups. It was observed that average male measurement were consistently larger than female by about 1 mm and the growth of the spinal canal appeared to be continued.

Measuring Oral Proficiency in Distance, Face-to-Face, and Blended Classrooms

Directory of Open Access Journals (Sweden)

Robert Blake

2008-10-01

Full Text Available Although the foreign-language profession routinely stresses the importance of technology for the curriculum, many teachers still harbor deep-seated doubts as to whether or not a hybrid course, much less a completely distance-learning class, could provide L2 learners with a way to reach linguistic proficiency, especially with respect to oral language skills. In this study, we examine the case of Spanish Without Walls (SWW, a first-year language course offered at the University of California - Davis in both hybrid and distance-learning formats. The SWW curriculum includes materials delivered via CD-ROM/DVD programs, online content-based web pages, and synchronous bimodal chat that includes sound and text. The contribution of each of these components is evaluated in the context of a successful technologically assisted course. To address the issue of oral proficiency, we compare the results from both classroom and distance-learning students who took the 20-minute Versant for Spanish test, delivered by phone and automatically graded. The data generated by this instrument shows that classroom, hybrid, and distance L2 learners reach comparable levels of oral proficiency during their first year of study. Reference is also made to two other ongoing efforts to provide distance-learning courses in Arabic and Punjabi, two languages where special difficulties in their writing systems have an impact on the design of the distant-learning format. The rationale for offering language courses in either a hybrid or distance-learning format is examined in light of increasing societal pressures to help L2 learners reach advanced proficiency, especially in less commonly taught languages (LCTLs.

Philtrum length and intercommissural distance measurements at mixed dentition period.

Science.gov (United States)

Mostafa, Mostafa; Hassib, Nehal; Sayed, Inas; Neamat, Amany; Ramzy, Magda; El-Badry, Tarek; ElGabry, Hisham; Salem, Haidy; Omar, Nada; Ismail, Amira; Ibrahim, Yousra; Shebaita, Amr; Allam, Ahmed; Mostafa, Magdy

2018-05-01

Anthropometric measurements of the lip and mouth are of great importance in clinical dysmorphology as well as reconstructive plastic surgery. In this study, the philtrum length (PhL) and intercommissural distance (ICmD) nomograms for Egyptian children in the mixed dentition period were established. A group of 1,338 Egyptian students in primary schools (735 boys and 603 girls) were included in the study. The students were at mixed dentition period and their ages ranged from 7 to 12 years. Anthropometric norms of PhL and ICmD were developed with significant sex difference in certain groups. A ratio between PhL and ICmD was developed. These data will help facilitate both objective and subjective evaluation of the lip and mouth for proper diagnosis of orofacial anomalies and variations as well as for ideal treatment plans. © 2018 Wiley Periodicals, Inc.

Measurement of mobility profile in ion-implanted silicon layers using electroreflection spectroscopy

International Nuclear Information System (INIS)

Galiev, G.B.; Kapaev, V.V.; Mokerov, V.G.

1986-01-01

The possibility is shown of the application of the low field linearized electroreflection spectroscopy for the measurement of profiles of carriers mobilities μ(x) simultaneously with the concentration profiles N(x) in thin ion-implanted silicon layers. The μ(χ) value is determined from the calibration curve of the dependence of the phenomenological broadening parameter γ on the mobility for uniformly doped samples. The results are presented for the measurements of the profiles μ(x) for boron- and arsenic-implanted silicon

Redox Behavior of Fe2+/Fe3+ Redox Couple by Absorption Spectroscopy and Measurement

International Nuclear Information System (INIS)

Oh, J. Y.; Park, S.; Yun, J. I.

2010-01-01

Redox behavior has influences on speciation and other geochemical reactions of radionuclides such as sorption, solubility, and colloid formation, etc. It is one of the factors for evaluation of long-term safety assessment under high-level radioactive waste (HLW) disposal conditions. Accordingly, redox potential (Eh) measurement in aquatic system is important to investigate the redox conditions. Eh is usually measured with redox active electrodes (Pt, Au, glassy carbon, etc.). Nevertheless, Eh measurements by general methods using electrodes provide low accuracy and high uncertainty problem. Therefore, Eh calculated from the concentration of redox active elements with a proper complexing reagent by using UV-Vis absorption spectroscopy is progressed. Iron exists mostly as spent nuclear waste container material and in hydro-geologic minerals. In this system, iron controls the redox condition in near-field area and influences chemical behavior and speciation of radionuclides including redox sensitive actinides such as U, Np, and Pu. In the present work, we present the investigation on redox phenomena of iron in aquatic system by a combination of absorption spectroscopy and redox potential measurements

Measurement of nuclear moments and radii by collinear laser spectroscopy

CERN Multimedia

Geithner, W R; Lievens, P; Kotrotsios, G; Silverans, R; Kappertz, S

2002-01-01

%IS304 %title\\\\ \\\\Collinear laser spectroscopy on a fast beam has proven to be a widely applicable and very efficient tool for measurements of changes in mean square nuclear charge radii, nuclear spins, magnetic dipole and electric quadrupole moments. Recent developments of extremely sensitive non-optical detection schemes enabled for some elements the extension of the measurements towards the very short-lived isotopes in the far wings of the ISOLDE production curves. The gain in sensitivity opens up new perspectives, particularly for measurements on lighter nuclei whose ground-state properties can be interpreted by large scale microscopic calculations instead of the more phenomenologic models used for heavier nuclei.\\\\ \\\\ For the sequence of argon isotopes $^{32-40}$Ar and $^{46}$Ar isotope shifts and nuclear moments were measured by optical pumping followed by state selective collisional ionization and detection of the $\\beta$-decay. Similarly, the low-background $\\alpha$-detection was used to extend earlie...

Fast and accurate measurement of on-axis gain and on-axis polarization at a finite distance

DEFF Research Database (Denmark)

Pivnenko, S.; Breinbjerg, O.

2013-01-01

-field substitution technique in which the measurement distance is defined between the phase centres of the antennas. The location of the phase centre of the antenna under test (AUT) is found from a quick pattern measurement consisting of only four cuts including the main and diagonal planes. Additionally, in order...... to reduce the amount of measurement data and thus measurement time, the phase centre location is found on a sparse frequency grid and the values in the intermediate points are found by interpolation. The antenna polarization is determined from the amplitude/phase frequency sweeps with two orthogonal AUT...

Multi-Segment Radius Measurement Using an Absolute Distance Meter Through a Null Assembly

Science.gov (United States)

Merle, Cormic; Wick, Eric; Hayden, Joseph

2011-01-01

This system was one of the test methods considered for measuring the radius of curvature of one or more of the 18 segmented mirrors that form the 6.5 m diameter primary mirror (PM) of the James Webb Space Telescope (JWST). The assembled telescope will be tested at cryogenic temperatures in a 17-m diameter by 27-m high vacuum chamber at the Johnson Space Center. This system uses a Leica Absolute Distance Meter (ADM), at a wavelength of 780 nm, combined with beam-steering and beam-shaping optics to make a differential distance measurement between a ring mirror on the reflective null assembly and individual PM segments. The ADM is located inside the same Pressure-Tight Enclosure (PTE) that houses the test interferometer. The PTE maintains the ADM and interferometer at ambient temperature and pressure so that they are not directly exposed to the telescope s harsh cryogenic and vacuum environment. This system takes advantage of the existing achromatic objective and reflective null assembly used by the test interferometer to direct four ADM beamlets to four PM segments through an optical path that is coincident with the interferometer beam. A mask, positioned on a linear slide, contains an array of 1.25 mm diameter circular subapertures that map to each of the 18 PM segments as well as six positions around the ring mirror. A down-collimated 4 mm ADM beam simultaneously covers 4 adjacent PM segment beamlets and one ring mirror beamlet. The radius, or spacing, of all 18 segments can be measured with the addition of two orthogonally-oriented scanning pentaprisms used to steer the ADM beam to any one of six different sub-aperture configurations at the plane of the ring mirror. The interferometer beam, at a wavelength of 687 nm, and the ADM beamlets, at a wavelength of 780 nm, pass through the objective and null so that the rays are normally incident on the parabolic PM surface. After reflecting off the PM, both the ADM and interferometer beams return to their respective

The Spectrum and Term Analysis of Co III Measured Using Fourier Transform and Grating Spectroscopy

Science.gov (United States)

Smillie, D. G.; Pickering, J. C.; Nave, G.; Smith, P. L.

2016-03-01

The spectrum of Co III has been recorded in the region 1562-2564 Å (64,000 cm-1-39,000 cm-1) by Fourier transform (FT) spectroscopy, and in the region 1317-2500 Å (164,000 cm-1-40,000 cm-1) using a 10.7 m grating spectrograph with phosphor image plate detectors. The spectrum was excited in a cobalt-neon Penning discharge lamp. We classified 514 Co III lines measured using FT spectroscopy, the strongest having wavenumber uncertainties approaching 0.004 cm-1 (approximately 0.2 mÅ at 2000 Å, or 1 part in 107), and 240 lines measured with grating spectroscopy with uncertainties between 5 and 10 mÅ. The wavelength calibration of 790 lines of Raassen & Ortí Ortin and 87 lines from Shenstone has been revised and combined with our measurements to optimize the values of all but one of the 288 previously reported energy levels. Order of magnitude reductions in uncertainty for almost two-thirds of the 3d64s and almost half of the 3d64p revised energy levels are obtained. Ritz wavelengths have been calculated for an additional 100 forbidden lines. Eigenvector percentage compositions for the energy levels and predicted oscillator strengths have been calculated using the Cowan code.

Comparison between measurements of hyperfine structures of Pr II - lines investigated by collinear laser ion beam spectroscopy (CLIBS) ans saturation spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Akhtar, Nadeem; Anjum, Naveed [Inst. f. Experimentalphysik, Techn. Univ. Graz, Petersgasse 16, A-8010 Graz (Austria); Optics Labs, Nilore, Islamabad (Pakistan); Huehnermann, Harry [Inst. f. Experimentalphysik, Techn. Univ. Graz, Petersgasse 16, A-8010 Graz (Austria); Fachbereich Physik, Univ. Marburg/Lahn (Germany); Windholz, Laurentius [Inst. f. Experimentalphysik, Techn. Univ. Graz, Petersgasse 16, A-8010 Graz (Austria)

2011-07-01

Investigation of narrow hyperfine structures needs a reduction of the Doppler broadening of the investigated lines. Here we have used two methods: collinear laser spectroscopy (CLIBS) and laser saturation spectroscopy. In the first method, the Doppler width is reduced by accelerating Pr ions to a high velocity and excitation with a collinear laser beam, while in the second method ions with velocity group zero are selected by nonlinear saturation. In this work the hyperfine spectra of several Pr II lines were investigated using CLIBS. A line width of ca. 60 MHz was measured. The same lines were then investigated in a hollow cathode discharge lamp using intermodulated laser-induced fluorescence spectroscopy. Using this technique a spectral line width of about 200 MHz was achieved. In both methods, the excitation source is a ring dye laser operated with R6G. Using a fit program, magnetic dipole interaction constants A and the electric-quadrupole interaction constants B of the involved levels have been determined in both cases. We discuss advantages and disadvantages of both methods.

Differentiation and detection of microorganisms using Fourier transform infrared photoacoustic spectroscopy

Science.gov (United States)

Irudayaraj, Joseph; Yang, Hong; Sakhamuri, Sivakesava

2002-03-01

Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) was used to differentiate and identify microorganisms on a food (apple) surface. Microorganisms considered include bacteria (Lactobacillus casei, Bacillus cereus, and Escherichia coli), yeast (Saccharomyces cerevisiae), and fungi (Aspergillus niger and Fusarium verticilliodes). Discriminant analysis was used to differentiate apples contaminated with the different microorganisms from uncontaminated apple. Mahalanobis distances were calculated to quantify the differences. The higher the value of the Mahalanobis distance metric between different microorganisms, the greater is their difference. Additionally, pathogenic (O157:H7) E. coli was successfully differentiated from non-pathogenic strains. Results demonstrate that FTIR-PAS spectroscopy has the potential to become a non-destructive analysis tool in food safety related research.

Reproducibility of 3.0 Tesla Magnetic Resonance Spectroscopy for Measuring Hepatic Fat Content

NARCIS (Netherlands)

van Werven, Jochem R.; Hoogduin, Johannes M.; Nederveen, Aart J.; van Vliet, Andre A.; Wajs, Ewa; Vandenberk, Petra; Stroes, Erik S. G.; Stoker, Jaap

Purpose: To investigate reproducibility of proton magnetic resonance spectroscopy (H-1-MRS) to measure hepatic triglyceride content (HTGC). Materials and Methods: In 24 subjects, HTGC was evaluated using H-1-MRS at 3.0 Tesla. We studied "between-weeks" reproducibility and reproducibility of H-1-MRS

A definition of distance and method of making space-time measurements

International Nuclear Information System (INIS)

Brisson, D.W.

1980-01-01

The paper explores an extended definition of the absolute value of a complex number and thus a new definition of distance. This new definition, called the nabsolute value of a complex number, is (Z) where Z = (a or ia) + (b or ib), so that (Z) is equivalent to [α 2 + β 2 ]sup(1/2), and α = a or ia, β = b or ib. This is shown on a superimposed X,Y plot and iX,iY plot so that four dimensions are represented in a plane. The application of this scheme to space-time measurement is then identified with the Minkowski Plane which has identical properties with the complex plane, with this new interpretation of the absolute value of a complex number. (Auth.)

Quantitative fluorescence spectroscopy in turbid media using fluorescence differential path length spectroscopy

NARCIS (Netherlands)

Amelink, Arjen; Kruijt, Bastiaan; Robinson, Dominic J.; Sterenborg, Henricus J. C. M.

2008-01-01

We have developed a new technique, fluorescence differential path length spectroscopy (FDPS), that enables the quantitative investigation of fluorophores in turbid media. FDPS measurements are made with the same probe geometry as differential path length spectroscopy (DPS) measurements. Phantom

In vivo time-gated diffuse correlation spectroscopy at quasi-null source-detector separation.

Science.gov (United States)

Pagliazzi, M; Sekar, S Konugolu Venkata; Di Sieno, L; Colombo, L; Durduran, T; Contini, D; Torricelli, A; Pifferi, A; Mora, A Dalla

2018-06-01

We demonstrate time domain diffuse correlation spectroscopy at quasi-null source-detector separation by using a fast time-gated single-photon avalanche diode without the need of time-tagging electronics. This approach allows for increased photon collection, simplified real-time instrumentation, and reduced probe dimensions. Depth discriminating, quasi-null distance measurement of blood flow in a human subject is presented. We envision the miniaturization and integration of matrices of optical sensors of increased spatial resolution and the enhancement of the contrast of local blood flow changes.

Phase-coded microwave signal generation based on a single electro-optical modulator and its application in accurate distance measurement.

Science.gov (United States)

Zhang, Fangzheng; Ge, Xiaozhong; Gao, Bindong; Pan, Shilong

2015-08-24

A novel scheme for photonic generation of a phase-coded microwave signal is proposed and its application in one-dimension distance measurement is demonstrated. The proposed signal generator has a simple and compact structure based on a single dual-polarization modulator. Besides, the generated phase-coded signal is stable and free from the DC and low-frequency backgrounds. An experiment is carried out. A 2 Gb/s phase-coded signal at 20 GHz is successfully generated, and the recovered phase information agrees well with the input 13-bit Barker code. To further investigate the performance of the proposed signal generator, its application in one-dimension distance measurement is demonstrated. The measurement accuracy is less than 1.7 centimeters within a measurement range of ~2 meters. The experimental results can verify the feasibility of the proposed phase-coded microwave signal generator and also provide strong evidence to support its practical applications.

Measurement of Moments and Radii of Light Nuclei by Collinear Fast-Beam Laser Spectroscopy and $\\beta$-NMR Spectroscopy

CERN Multimedia

Marinova, K P

2002-01-01

Nuclear Moments and radii of light unstable isotopes are investigated by applying different high-sensitivity and high-resolution techniques based on collinear fast-beam laser spectroscopy. A study of nuclear structure in the sd shell is performed on neon isotopes in the extended chain of $^{17-28}$Ne, in particular on the proton-halo candidate $^{17}$Ne. Measurements of hyperfine structure and isotope shift have become possible by introducing an ultra-sensitive non-optical detection method which is based on optical pumping, state-selective collisional ionization and $\\beta$-activity counting. The small effect of nuclear radii on the optical isotope shifts of light elements requires very accurate measurements. The errors are dominated by uncertainties of the Doppler shifts which are conventionally determined from precisely measured acceleration voltages. These uncertainties are removed by measuring the beam energy with simultaneous excitation of two optical lines in parallel / antiparallel beam configuration. ...

Moving gantry method for electron beam dose profile measurement at extended source-to-surface distances.

Science.gov (United States)

Fekete, Gábor; Fodor, Emese; Pesznyák, Csilla

2015-03-08

A novel method has been put forward for very large electron beam profile measurement. With this method, absorbed dose profiles can be measured at any depth in a solid phantom for total skin electron therapy. Electron beam dose profiles were collected with two different methods. Profile measurements were performed at 0.2 and 1.2 cm depths with a parallel plate and a thimble chamber, respectively. 108cm × 108 cm and 45 cm × 45 cm projected size electron beams were scanned by vertically moving phantom and detector at 300 cm source-to-surface distance with 90° and 270° gantry angles. The profiles collected this way were used as reference. Afterwards, the phantom was fixed on the central axis and the gantry was rotated with certain angular steps. After applying correction for the different source-to-detector distances and incidence of angle, the profiles measured in the two different setups were compared. Correction formalism has been developed. The agreement between the cross profiles taken at the depth of maximum dose with the 'classical' scanning and with the new moving gantry method was better than 0.5 % in the measuring range from zero to 71.9 cm. Inverse square and attenuation corrections had to be applied. The profiles measured with the parallel plate chamber agree better than 1%, except for the penumbra region, where the maximum difference is 1.5%. With the moving gantry method, very large electron field profiles can be measured at any depth in a solid phantom with high accuracy and reproducibility and with much less time per step. No special instrumentation is needed. The method can be used for commissioning of very large electron beams for computer-assisted treatment planning, for designing beam modifiers to improve dose uniformity, and for verification of computed dose profiles.

Measuring depth profiles of residual stress with Raman spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Enloe, W.S.; Sparks, R.G.; Paesler, M.A.

1988-12-01

Knowledge of the variation of residual stress is a very important factor in understanding the properties of machined surfaces. The nature of the residual stress can determine a part`s susceptibility to wear deformation, and cracking. Raman spectroscopy is known to be a very useful technique for measuring residual stress in many materials. These measurements are routinely made with a lateral resolution of 1{mu}m and an accuracy of 0.1 kbar. The variation of stress with depth; however, has not received much attention in the past. A novel technique has been developed that allows quantitative measurement of the variation of the residual stress with depth with an accuracy of 10nm in the z direction. Qualitative techniques for determining whether the stress is varying with depth are presented. It is also demonstrated that when the stress is changing over the volume sampled, errors can be introduced if the variation of the stress with depth is ignored. Computer aided data analysis is used to determine the depth dependence of the residual stress.

DL-sQUAL: A Multiple-Item Scale for Measuring Service Quality of Online Distance Learning Programs

Science.gov (United States)

Shaik, Naj; Lowe, Sue; Pinegar, Kem

2006-01-01

Education is a service with multiplicity of student interactions over time and across multiple touch points. Quality teaching needs to be supplemented by consistent quality supporting services for programs to succeed under the competitive distance learning landscape. ServQual and e-SQ scales have been proposed for measuring quality of traditional…

On the importance of the distance measures used to train and test knowledge-based potentials for proteins.

Directory of Open Access Journals (Sweden)

Martin Carlsen

Full Text Available Knowledge-based potentials are energy functions derived from the analysis of databases of protein structures and sequences. They can be divided into two classes. Potentials from the first class are based on a direct conversion of the distributions of some geometric properties observed in native protein structures into energy values, while potentials from the second class are trained to mimic quantitatively the geometric differences between incorrectly folded models and native structures. In this paper, we focus on the relationship between energy and geometry when training the second class of knowledge-based potentials. We assume that the difference in energy between a decoy structure and the corresponding native structure is linearly related to the distance between the two structures. We trained two distance-based knowledge-based potentials accordingly, one based on all inter-residue distances (PPD, while the other had the set of all distances filtered to reflect consistency in an ensemble of decoys (PPE. We tested four types of metric to characterize the distance between the decoy and the native structure, two based on extrinsic geometry (RMSD and GTD-TS*, and two based on intrinsic geometry (Q* and MT. The corresponding eight potentials were tested on a large collection of decoy sets. We found that it is usually better to train a potential using an intrinsic distance measure. We also found that PPE outperforms PPD, emphasizing the benefits of capturing consistent information in an ensemble. The relevance of these results for the design of knowledge-based potentials is discussed.

Gamma-ray spectroscopy measurements and simulations for uranium mining

Science.gov (United States)

Marchais, T.; Pérot, B.; Carasco, C.; Allinei, P.-G.; Chaussonnet, P.; Ma, J.-L.; Toubon, H.

2018-01-01

AREVA Mines and the Nuclear Measurement Laboratory of CEA Cadarache are collaborating to improve the sensitivity and precision of uranium concentration evaluation by means of gamma measurements. This paper reports gamma-ray spectra, recorded with a high-purity coaxial germanium detector, on standard cement blocks with increasing uranium content, and the corresponding MCNP simulations. The detailed MCNP model of the detector and experimental setup has been validated by calculation vs. experiment comparisons. An optimization of the detector MCNP model is presented in this paper, as well as a comparison of different nuclear data libraries to explain missing or exceeding peaks in the simulation. Energy shifts observed between the fluorescence X-rays produced by MCNP and atomic data are also investigated. The qualified numerical model will be used in further studies to develop new gamma spectroscopy approaches aiming at reducing acquisition times, especially for ore samples with low uranium content.

Optical Spectroscopy Measurements of Shock Waves Driven by Intense Z-Pinch Radiation

International Nuclear Information System (INIS)

Asay, J.; Bernard, M.; Bailey, J.E.; Carlson, A.L.; Chandler, G.A.; Hall, C.A.; Hanson, D.; Johnston, R.; Lake, P.; Lawrence, J.

1999-01-01

Z-pinches created using the Z accelerator generate approximately220 TW, 1.7 MJ radiation pulses that heat large (approximately10 cm 3 ) hohlraums to 100-150 eV temperatures for times of order 10 nsec. We are performing experiments exploiting this intense radiation to drive shock waves for equation of state studies. The shock pressures are typically 1-10 Mbar with 10 nsec duration in 6-mm-diameter samples. In this paper we demonstrate the ability to perform optical spectroscopy measurements on shocked samples located in close proximity to the z-pinch. These experiments are particularly well suited to optical spectroscopy measurements because of the relatively large sample size and long duration. The optical emission is collected using fiber optics and recorded with a streaked spectrograph. Other diagnostics include VISAR and active shock breakout measurements of the shocked sample and a suite of diagnostics that characterize the radiation drive. Our near term goal is to use the spectral emission to obtain the temperature of the shocked material. Longer term objectives include the examination of deviations of the spectrum from blackbody, line emission from lower density regions, determination of kinetic processes in molecular systems, evaluation of phase transitions such as the onset of metalization in transparent materials, and characterization of the plasma formed when the shock exits the rear surface. An initial set of data illustrating both the potential and the challenge of these measurements is described

Demonstration of a Fast, Precise Propane Measurement Using Infrared Spectroscopy

Science.gov (United States)

Zahniser, M. S.; Roscioli, J. R.; Nelson, D. D.; Herndon, S. C.

2016-12-01

Propane is one of the primary components of emissions from natural gas extraction and processing activities. In addition to being an air pollutant, its ratio to other hydrocarbons such as methane and ethane can serve as a "fingerprint" of a particular facility or process, aiding in identifying emission sources. Quantifying propane has typically required laboratory analysis of flask samples, resulting in low temporal resolution and making plume-based measurements infeasible. Here we demonstrate fast (1-second), high precision (infrared spectroscopy at 2967 wavenumbers. In addition, we explore the impact of nearby water and ethane absorption lines on the accuracy and precision of the propane measurement. Finally, we discuss development of a dual-laser instrument capable of simultaneous measurements of methane, ethane, and propane (the C1-C3 compounds), all within a small spatial package that can be easily deployed aboard a mobile platform.

Absolute distance measurement with micrometer accuracy using a Michelson interferometer and the iterative synthetic wavelength principle.

Science.gov (United States)

Alzahrani, Khaled; Burton, David; Lilley, Francis; Gdeisat, Munther; Bezombes, Frederic; Qudeisat, Mohammad

2012-02-27

We present a novel system that can measure absolute distances of up to 300 mm with an uncertainty of the order of one micrometer, within a timeframe of 40 seconds. The proposed system uses a Michelson interferometer, a tunable laser, a wavelength meter and a computer for analysis. The principle of synthetic wave creation is used in a novel way in that the system employs an initial low precision estimate of the distance, obtained using a triangulation, or time-of-flight, laser system, or similar, and then iterates through a sequence of progressively smaller synthetic wavelengths until it reaches micrometer uncertainties in the determination of the distance. A further novel feature of the system is its use of Fourier transform phase analysis techniques to achieve sub-wavelength accuracy. This method has the major advantages of being relatively simple to realize, offering demonstrated high relative precisions better than 5 × 10(-5). Finally, the fact that this device does not require a continuous line-of-sight to the target as is the case with other configurations offers significant advantages.

The interuncal distance in elderly patients with dementia

International Nuclear Information System (INIS)

Hanyu, Haruo; Takasaki, Masaru; Sugiyama, Takeshi; Abe, Shinei; Kobayashi, Yasutaka; Maehata, Yukihiko; Katsunuma, Hidetaka.

1993-01-01

The interuncal distance between the unci of the temporal lobes was measured from axial MR images of the brain in elderly patients with dementia including dementia of the Alzheimer type (DAT), vascular dementia (VD), and others. The measured value of the interuncal distance completely separated patients with DAT from normal controls, and there was significant diference in the interuncal distance between patients with DAT and VD. This measurement is a practical method of assessing hippocampal atrophy and appears to be a useful adjunct in the clinical diagnosis of DAT. (author)

Raman Spectroscopy for Homeland Security Applications

Directory of Open Access Journals (Sweden)

Gregory Mogilevsky

2012-01-01

Full Text Available Raman spectroscopy is an analytical technique with vast applications in the homeland security and defense arenas. The Raman effect is defined by the inelastic interaction of the incident laser with the analyte molecule’s vibrational modes, which can be exploited to detect and identify chemicals in various environments and for the detection of hazards in the field, at checkpoints, or in a forensic laboratory with no contact with the substance. A major source of error that overwhelms the Raman signal is fluorescence caused by the background and the sample matrix. Novel methods are being developed to enhance the Raman signal’s sensitivity and to reduce the effects of fluorescence by altering how the hazard material interacts with its environment and the incident laser. Basic Raman techniques applicable to homeland security applications include conventional (off-resonance Raman spectroscopy, surface-enhanced Raman spectroscopy (SERS, resonance Raman spectroscopy, and spatially or temporally offset Raman spectroscopy (SORS and TORS. Additional emerging Raman techniques, including remote Raman detection, Raman imaging, and Heterodyne imaging, are being developed to further enhance the Raman signal, mitigate fluorescence effects, and monitor hazards at a distance for use in homeland security and defense applications.

Auditory/visual distance estimation: accuracy and variability

Directory of Open Access Journals (Sweden)

Paul Wallace Anderson

2014-10-01

Full Text Available Past research has shown that auditory distance estimation improves when listeners are given the opportunity to see all possible sound sources when compared to no visual input. It has also been established that distance estimation is more accurate in vision than in audition. The present study investigates the degree to which auditory distance estimation is improved when matched with a congruent visual stimulus. Virtual sound sources based on binaural room impulse response (BRIR measurements made from distances ranging from approximately 0.3 to 9.8 m in a concert hall were used as auditory stimuli. Visual stimuli were photographs taken from the listener’s perspective at each distance in the impulse response measurement setup presented on a large HDTV monitor. Listeners were asked to estimate egocentric distance to the sound source in each of three conditions: auditory only (A, visual only (V, and congruent auditory/visual stimuli (A+V. Each condition was presented within its own block. Sixty-two listeners were tested in order to quantify the response variability inherent in auditory distance perception. Distance estimates from both the V and A+V conditions were found to be considerably more accurate and less variable than estimates from the A condition.

Time-Distance Helioseismology: Noise Estimation

Science.gov (United States)

Gizon, L.; Birch, A. C.

2004-10-01

As in global helioseismology, the dominant source of noise in time-distance helioseismology measurements is realization noise due to the stochastic nature of the excitation mechanism of solar oscillations. Characterizing noise is important for the interpretation and inversion of time-distance measurements. In this paper we introduce a robust definition of travel time that can be applied to very noisy data. We then derive a simple model for the full covariance matrix of the travel-time measurements. This model depends only on the expectation value of the filtered power spectrum and assumes that solar oscillations are stationary and homogeneous on the solar surface. The validity of the model is confirmed through comparison with SOHO MDI measurements in a quiet-Sun region. We show that the correlation length of the noise in the travel times is about half the dominant wavelength of the filtered power spectrum. We also show that the signal-to-noise ratio in quiet-Sun travel-time maps increases roughly as the square root of the observation time and is at maximum for a distance near half the length scale of supergranulation.

Assessing distances and consistency of kinematics in Gaia/TGAS

Science.gov (United States)

Schönrich, Ralph; Aumer, Michael

2017-12-01

We apply the statistical methods by Schönrich, Binney & Asplund to assess the quality of distances and kinematics in the Radial Velocity Experiment (RAVE)-Tycho-Gaia Astrometric Solution (TGAS) and Large Sky Area Multiobject Fiber Spectroscopic Telescope (LAMOST)-TGAS samples of Solar neighbourhood stars. These methods yield a nominal distance accuracy of 1-2 per cent. Other than common tests on parallax accuracy, they directly test distance estimations including the effects of distance priors. We show how to construct these priors including the survey selection functions (SSFs) directly from the data. We demonstrate that neglecting the SSFs causes severe distance biases. Due to the decline of the SSFs in distance, the simple 1/parallax estimate only mildly underestimates distances. We test the accuracy of measured line-of-sight velocities (vlos) by binning the samples in the nominal vlos uncertainties. We find: (i) the LAMOST vlos have a ∼-5 km s-1 offset; (ii) the average LAMOST measurement error for vlos is ∼7 km s-1, significantly smaller than, and nearly uncorrelated with the nominal LAMOST estimates. The RAVE sample shows either a moderate distance underestimate, or an unaccounted source of vlos dispersion (e∥) from measurement errors and binary stars. For a subsample of suspected binary stars in RAVE, our methods indicate significant distance underestimates. Separating a sample in metallicity or kinematics to select thick-disc/halo stars, discriminates between distance bias and e∥. For LAMOST, this separation yields consistency with pure vlos measurement errors. We find an anomaly near longitude l ∼ (300 ± 60)° and distance s ∼ (0.32 ± 0.03) kpc on both sides of the galactic plane, which could be explained by either a localized distance error or a breathing mode.

Measurement of adenosine triphosphate and 2,3-diphosphoglycerate in stored blood with 31P nuclear magnetic resonance spectroscopy.

Science.gov (United States)

Ambruso, D R; Hawkins, B; Johnson, D L; Fritzberg, A R; Klingensmith, W C; McCabe, E R

1986-06-01

Conditions for blood storage are chosen to assure adequate levels of adenosine triphosphate (ATP) and 2,3-diphosphoglycerate (2,3-DPG). Because of the invasive nature of the techniques, biochemical assays are not routinely used to measure levels of these compounds in stored blood. However, 31P NMR spectroscopy measures phosphorylated intermediates in intact cells and could be used without disruption of the storage pack. We compared levels of ATP and 2,3-DPG measured by 31P spectroscopy and standard enzyme-linked biochemical assays in whole blood (WB) and packed red blood cells (PRBCs) at weekly intervals during a 35-day storage period. NMR demonstrated a marked decrease in 2,3-DPG and an increase in inorganic phosphate after the first week of storage. No significant differences in ATP concentrations were seen in WB during the storage period, but a significant decrease in ATP in PRBCs was documented. There was good agreement in levels of ATP and 2,3-DPG measured by NMR and biochemical techniques. 31P NMR spectroscopy is a noninvasive technique for measuring ATP and 2,3-DPG which has a potential use in quality assurance of stored blood.

THE SPECTRUM AND TERM ANALYSIS OF CO iii MEASURED USING FOURIER TRANSFORM AND GRATING SPECTROSCOPY

Energy Technology Data Exchange (ETDEWEB)

Smillie, D. G.; Pickering, J. C. [Blackett Laboratory, Imperial College London, London SW7 2AZ (United Kingdom); Nave, G. [National Institute of Standards and Technology, Gaithersburg, MD 20899-8422 (United States); Smith, P. L., E-mail: j.pickering@imperial.ac.uk [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2016-03-15

The spectrum of Co iii has been recorded in the region 1562–2564 Å (64,000 cm{sup −1}–39,000 cm{sup −1}) by Fourier transform (FT) spectroscopy, and in the region 1317–2500 Å (164,000 cm{sup −1}–40,000 cm{sup −1}) using a 10.7 m grating spectrograph with phosphor image plate detectors. The spectrum was excited in a cobalt–neon Penning discharge lamp. We classified 514 Co iii lines measured using FT spectroscopy, the strongest having wavenumber uncertainties approaching 0.004 cm{sup −1} (approximately 0.2 mÅ at 2000 Å, or 1 part in 10{sup 7}), and 240 lines measured with grating spectroscopy with uncertainties between 5 and 10 mÅ. The wavelength calibration of 790 lines of Raassen and Ortí Ortin and 87 lines from Shenstone has been revised and combined with our measurements to optimize the values of all but one of the 288 previously reported energy levels. Order of magnitude reductions in uncertainty for almost two-thirds of the 3d{sup 6}4s and almost half of the 3d{sup 6}4p revised energy levels are obtained. Ritz wavelengths have been calculated for an additional 100 forbidden lines. Eigenvector percentage compositions for the energy levels and predicted oscillator strengths have been calculated using the Cowan code.

Interuncal distance measurements in normal controls and patients with dementia. MR imaging study

International Nuclear Information System (INIS)

Ishii, Kazunari; Kitagaki, Hajime; Sakamoto, Setsu; Yamaji, Shigeru; Kono, Michio.

1995-01-01

To evaluate the utility of measuring interuncal distance (IUD) as a reflection of the limbic system, we compared the IUD of 60 dementia patients with that of 10 normal controls. We also measured the width of the intracranial compartment (W1 and W2) to correct for differences in individual brain size, and calculated the ratio of IUD/W1 and IUD/W2. IUD could not separate patients with dementia from normal controls, but there were significant differences in IUD/W1 and IUD/W2 between patients with dementia and normal controls. IUD, IUD/W1 and IUD/W2 did not correlate with Mini-Mental Examination score or ADAS score in patients with dementia. We conclude that IUD measurement is not helpful in distinguishing patients with mild stage dementia from normal aged people or as a scale for dementia. However, we suggest that IUD/W1 and IUD/W2 can discriminate between cases of mild dementia and normal aged people. (author)

Force spectroscopy of membrane hardness of SH-SY5Y neuroblastoma cells before and after differentiation

Science.gov (United States)

Kwon, Sangwoo; Yang, Woochul; Choi, Yun Kyong; Park, Jung Keuck

2014-05-01

Atomic force microscopy (AFM) is utilized in many studies for measuring the structure and the physical characteristics of soft and bio materials. In particular, the force spectroscopy function in the AFM system allows us to explore the mechanical properties of bio cells. In this study, we probe the variation in the membrane hardness of human neuroblastoma SH-SY5Y cells (SH-cells) before and after differentiation by using force spectroscopy. The SH-cell, which is usually differentiated by using a chemical treatment with retinoic acid (RA), is a neuronal cell line employed widely as an in-vitro model for neuroscience research. In force spectroscopy, the force-distance curves are obtained from both the original and the RA-treated cells while the AFM tip approaches and pushes on the cell membranes. The slope deduced from linear region in the force-distance curve is the spring constant and corresponds to the hardness of the cell membrane. The spring constant of the RA-treated cells (0.597 ± 0.010 nN/nm) was smaller than that of the original cells (0.794 ± 0.010 nN/nm), reflecting a hardness decrease in the cells differentiated with the RA treatments. The results clearly demonstrated that the differentiated cells are softer than the original cells. The change in the elasticity of the differentiated cells might be caused by morphological modification during differentiation process. We suggest that force spectroscopy can be employed as a novel method to determine the degree of differentiation of stem cells into various functional cells.

Nanomechanical characterization by double-pass force-distance mapping

Energy Technology Data Exchange (ETDEWEB)

Dagdas, Yavuz S; Tekinay, Ayse B; Guler, Mustafa O; Dana, Aykutlu [UNAM Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara (Turkey); Necip Aslan, M, E-mail: aykutlu@unam.bilkent.edu.tr [Department of Physics, Istanbul Technical University, Istanbul (Turkey)

2011-07-22

We demonstrate high speed force-distance mapping using a double-pass scheme. The topography is measured in tapping mode in the first pass and this information is used in the second pass to move the tip over the sample. In the second pass, the cantilever dither signal is turned off and the sample is vibrated. Rapid (few kHz frequency) force-distance curves can be recorded with small peak interaction force, and can be processed into an image. Such a double-pass measurement eliminates the need for feedback during force-distance measurements. The method is demonstrated on self-assembled peptidic nanofibers.

Nanomechanical characterization by double-pass force-distance mapping

International Nuclear Information System (INIS)

Dagdas, Yavuz S; Tekinay, Ayse B; Guler, Mustafa O; Dana, Aykutlu; Necip Aslan, M

2011-01-01

We demonstrate high speed force-distance mapping using a double-pass scheme. The topography is measured in tapping mode in the first pass and this information is used in the second pass to move the tip over the sample. In the second pass, the cantilever dither signal is turned off and the sample is vibrated. Rapid (few kHz frequency) force-distance curves can be recorded with small peak interaction force, and can be processed into an image. Such a double-pass measurement eliminates the need for feedback during force-distance measurements. The method is demonstrated on self-assembled peptidic nanofibers.

Multidimensional high harmonic spectroscopy

International Nuclear Information System (INIS)

Bruner, Barry D; Soifer, Hadas; Shafir, Dror; Dudovich, Nirit; Serbinenko, Valeria; Smirnova, Olga

2015-01-01

High harmonic generation (HHG) has opened up a new frontier in ultrafast science where attosecond time resolution and Angstrom spatial resolution are accessible in a single measurement. However, reconstructing the dynamics under study is limited by the multiple degrees of freedom involved in strong field interactions. In this paper we describe a new class of measurement schemes for resolving attosecond dynamics, integrating perturbative nonlinear optics with strong-field physics. These approaches serve as a basis for multidimensional high harmonic spectroscopy. Specifically, we show that multidimensional high harmonic spectroscopy can measure tunnel ionization dynamics with high precision, and resolves the interference between multiple ionization channels. In addition, we show how multidimensional HHG can function as a type of lock-in amplifier measurement. Similar to multi-dimensional approaches in nonlinear optical spectroscopy that have resolved correlated femtosecond dynamics, multi-dimensional high harmonic spectroscopy reveals the underlying complex dynamics behind attosecond scale phenomena. (paper)

A comparison of 3-D computed tomography versus 2-D radiography measurements of ulnar variance and ulnolunate distance during forearm rotation.

Science.gov (United States)

Kawanishi, Y; Moritomo, H; Omori, S; Kataoka, T; Murase, T; Sugamoto, K

2014-06-01

Positive ulnar variance is associated with ulnar impaction syndrome and ulnar variance is reported to increase with pronation. However, radiographic measurement can be affected markedly by the incident angle of the X-ray beam. We performed three-dimensional (3-D) computed tomography measurements of ulnar variance and ulnolunate distance during forearm rotation and compared these with plain radiographic measurements in 15 healthy wrists. From supination to pronation, ulnar variance increased in all cases on the radiographs; mean ulnar variance increased significantly and mean ulnolunate distance decreased significantly. However on 3-D imaging, ulna variance decreased in 12 cases on moving into pronation and increased in three cases; neither the mean ulnar variance nor mean ulnolunate distance changed significantly. Our results suggest that the forearm position in which ulnar variance increased varies among individuals. This may explain why some patients with ulnar impaction syndrome complain of wrist pain exacerbated by forearm supination. It also suggests that standard radiographic assessments of ulnar variance are unreliable. © The Author(s) 2013.

Tuneable diode laser spectroscopy correction factor investigation on ammonia measurement

Science.gov (United States)

Li, Nilton; El-Hamalawi, Ashraf; Baxter, Jim; Barrett, Richard; Wheatley, Andrew

2018-01-01

Current diesel engine aftertreatment systems, such as Selective Catalyst Reduction (SCR) use ammonia (NH3) to reduce Nitrogen Oxides (NOx) into Nitrogen (N2) and water (H2O). However, if the reaction between NH3 and NOx is unbalanced, it can lead either NH3 or NOx being released into the environment. As NH3 is classified as a dangerous compound in the environment, its accurate measurement is essential. Tuneable Diode Laser (TDL) spectroscopy is one of the methods used to measure raw emissions inside engine exhaust pipes, especially NH3. This instrument requires a real-time exhaust temperature, pressure and other interference compounds in order to adjust itself to reduce the error in NH3 readings. Most researchers believed that exhaust temperature and pressure were the most influential factors in TDL when measuring NH3 inside exhaust pipes. The aim of this paper was to quantify these interference effects on TDL when undertaking NH3 measurement. Surprisingly, the results show that pressure was the least influential factor when compared to temperature, H2O, CO2 and O2 when undertaking NH3 measurement using TDL.

A VLBI resolution of the Pleiades distance controversy.

Science.gov (United States)

Melis, Carl; Reid, Mark J; Mioduszewski, Amy J; Stauffer, John R; Bower, Geoffrey C

2014-08-29

Because of its proximity and its youth, the Pleiades open cluster of stars has been extensively studied and serves as a cornerstone for our understanding of the physical properties of young stars. This role is called into question by the "Pleiades distance controversy," wherein the cluster distance of 120.2 ± 1.5 parsecs (pc) as measured by the optical space astrometry mission Hipparcos is significantly different from the distance of 133.5 ± 1.2 pc derived with other techniques. We present an absolute trigonometric parallax distance measurement to the Pleiades cluster that uses very long baseline radio interferometry (VLBI). This distance of 136.2 ± 1.2 pc is the most accurate and precise yet presented for the cluster and is incompatible with the Hipparcos distance determination. Our results cement existing astrophysical models for Pleiades-age stars. Copyright © 2014, American Association for the Advancement of Science.

Distribution of Fe atom density in a dc magnetron sputtering plasma source measured by laser-induced fluorescence imaging spectroscopy

Science.gov (United States)

Shibagaki, K.; Nafarizal, N.; Sasaki, K.; Toyoda, H.; Iwata, S.; Kato, T.; Tsunashima, S.; Sugai, H.

2003-10-01

Magnetron sputtering discharge is widely used as an efficient method for thin film fabrication. In order to achieve the optimized fabrication, understanding of the kinetics in plasmas is essential. In the present work, we measured the density distribution of sputtered Fe atoms using laser-induced fluorescence imaging spectroscopy. A dc magnetron plasma source with a Fe target was used. An area of 20 × 2 mm in front of the target was irradiated by a tunable laser beam having a planar shape. The picture of laser-induced fluorescence on the laser beam was taken using an ICCD camera. In this way, we obtained the two-dimensional image of the Fe atom density. As a result, it has been found that the Fe atom density observed at a distance of several centimeters from the target is higher than that adjacent to the target, when the Ar gas pressure was relatively high. It is suggested from this result that some gas-phase production processes of Fe atoms are available in the plasma. This work has been performed under the 21st Century COE Program by the Ministry of Education, Culture, Sports, Science and Technology in Japan.

Measurement of the spectrum of electric-field fluctuations in a plasma by laser-fluorescence spectroscopy

International Nuclear Information System (INIS)

Hildebrandt, J.; Kunze, H.

1980-01-01

Laser-fluorescence spectroscopy has been applied to measure the spectrum of electric wave fields with high temporal resolution in a pulsed hollow-cathode discharge. A low-frequency and a high-frequency component can be identified

Particle influx measurements with the ASDEX-upgrade multichord visible spectroscopy system

International Nuclear Information System (INIS)

Kallenbach, A.; Mayer, H.M.; Schneider, W.

1992-01-01

This report describes the hardware and software components of the ASDEX-Upgrade multichord visible spectroscopy system. Main emphasis is laid on a detailed description of the detector, a free programmable charge-coupled device intensified by a microchannel plate. As an experimental application, flux measurements of different impurity species from the inner heat shield are presented. Poloidal profiles of the released impurity amount obtained for various experimental situations are used to check the plasma position which is derived by the function parametrization analysis. (orig.)

LEAD SLOWING DOWN SPECTROSCOPY FOR DIRECT Pu MASS MEASUREMENTS

International Nuclear Information System (INIS)

Ressler, Jennifer J.; Smith, Leon E.; Anderson, Kevin K.

2008-01-01

The direct measurement of Pu in previously irradiated fuel assemblies is a recognized need in the international safeguards community. A suitable technology could support more timely and independent material control and accounting (MC and A) measurements at nuclear fuel storage areas, the head-end of reprocessing facilities, and at the product-end of recycled fuel fabrication. Lead slowing down spectroscopy (LSDS) may be a viable solution for directly measuring not only the mass of 239Pu in fuel assemblies, but also the masses of other fissile isotopes such as 235U and 241Pu. To assess the potential viability of LSDS, an LSDS spectrometer was modeled in MCNP5 and 'virtual assays' of nominal PWR assemblies ranging from 0 to 60 GWd/MTU burnup were completed. Signal extraction methods, including the incorporation of nonlinear fitting to account for self-shielding effects in strong resonance regions, are described. Quantitative estimates of Pu uncertainty are given for simplistic and more realistic fuel isotopic inventories calculated using ORIGEN. A discussion of additional signal-perturbing effects that will be addressed in future work, and potential signal extraction approaches that could improve Pu mass uncertainties, are also discussed

Simultaneous measurement of temperature, stress, and electric field in GaN HEMTs with micro-Raman spectroscopy.

Science.gov (United States)

Bagnall, Kevin R; Moore, Elizabeth A; Badescu, Stefan C; Zhang, Lenan; Wang, Evelyn N

2017-11-01

As semiconductor devices based on silicon reach their intrinsic material limits, compound semiconductors, such as gallium nitride (GaN), are gaining increasing interest for high performance, solid-state transistor applications. Unfortunately, higher voltage, current, and/or power levels in GaN high electron mobility transistors (HEMTs) often result in elevated device temperatures, degraded performance, and shorter lifetimes. Although micro-Raman spectroscopy has become one of the most popular techniques for measuring localized temperature rise in GaN HEMTs for reliability assessment, decoupling the effects of temperature, mechanical stress, and electric field on the optical phonon frequencies measured by micro-Raman spectroscopy is challenging. In this work, we demonstrate the simultaneous measurement of temperature rise, inverse piezoelectric stress, thermoelastic stress, and vertical electric field via micro-Raman spectroscopy from the shifts of the E 2 (high), A 1 longitudinal optical (LO), and E 2 (low) optical phonon frequencies in wurtzite GaN. We also validate experimentally that the pinched OFF state as the unpowered reference accurately measures the temperature rise by removing the effect of the vertical electric field on the Raman spectrum and that the vertical electric field is approximately the same whether the channel is open or closed. Our experimental results are in good quantitative agreement with a 3D electro-thermo-mechanical model of the HEMT we tested and indicate that the GaN buffer acts as a semi-insulating, p-type material due to the presence of deep acceptors in the lower half of the bandgap. This implementation of micro-Raman spectroscopy offers an exciting opportunity to simultaneously probe thermal, mechanical, and electrical phenomena in semiconductor devices under bias, providing unique insight into the complex physics that describes device behavior and reliability. Although GaN HEMTs have been specifically used in this study to

Simultaneous measurement of temperature, stress, and electric field in GaN HEMTs with micro-Raman spectroscopy

Science.gov (United States)

Bagnall, Kevin R.; Moore, Elizabeth A.; Badescu, Stefan C.; Zhang, Lenan; Wang, Evelyn N.

2017-11-01

As semiconductor devices based on silicon reach their intrinsic material limits, compound semiconductors, such as gallium nitride (GaN), are gaining increasing interest for high performance, solid-state transistor applications. Unfortunately, higher voltage, current, and/or power levels in GaN high electron mobility transistors (HEMTs) often result in elevated device temperatures, degraded performance, and shorter lifetimes. Although micro-Raman spectroscopy has become one of the most popular techniques for measuring localized temperature rise in GaN HEMTs for reliability assessment, decoupling the effects of temperature, mechanical stress, and electric field on the optical phonon frequencies measured by micro-Raman spectroscopy is challenging. In this work, we demonstrate the simultaneous measurement of temperature rise, inverse piezoelectric stress, thermoelastic stress, and vertical electric field via micro-Raman spectroscopy from the shifts of the E2 (high), A1 longitudinal optical (LO), and E2 (low) optical phonon frequencies in wurtzite GaN. We also validate experimentally that the pinched OFF state as the unpowered reference accurately measures the temperature rise by removing the effect of the vertical electric field on the Raman spectrum and that the vertical electric field is approximately the same whether the channel is open or closed. Our experimental results are in good quantitative agreement with a 3D electro-thermo-mechanical model of the HEMT we tested and indicate that the GaN buffer acts as a semi-insulating, p-type material due to the presence of deep acceptors in the lower half of the bandgap. This implementation of micro-Raman spectroscopy offers an exciting opportunity to simultaneously probe thermal, mechanical, and electrical phenomena in semiconductor devices under bias, providing unique insight into the complex physics that describes device behavior and reliability. Although GaN HEMTs have been specifically used in this study to

Study of the structural modifications in activated clays by Moessbauer spectroscopy and X-ray diffractometry

Energy Technology Data Exchange (ETDEWEB)

Huaypar, Yezena, E-mail: yhuaypar@yahoo.es; Bravo, Jorge, E-mail: jbravoc@unmsm.edu.pe [Universidad Nacional Mayor de San Marcos, Facultad de Ciencias Fisicas (Peru); Gutarra, Abel; Gabriel, Erika [Universidad Nacional de Ingenieria, Facultad de Ciencias (Peru)

2007-02-15

In this work we study the changes induced on the structure of a smectite clay by chemical acid activation with HCl using X-ray diffractometry (XRD) and transmission Moessbauer spectroscopy (TMS) techniques. By XRD we were able to determine the mineralogical composition of the clay samples and measure the changes in the interplanar distance associated to the structural modifications in the clays. We measured a reduction in the interplanar distance and reflection intensity as the acid concentration in the activation process increased. TMS allowed us identify and characterize the structural sites occupied by ferric and ferrous iron cations. In addition, we were able to monitor the effects caused by the chemical acid activation on the valence state of the iron cations that occupy these structural sites in the clay. For the treatment at low acid concentration, keeping time and temperature of activation constant, our results showed a strong effect on the ferrous and ferric iron sites, reducing and increasing their adsorption relative areas respectively.

Study of the structural modifications in activated clays by Moessbauer spectroscopy and X-ray diffractometry

International Nuclear Information System (INIS)

Huaypar, Yezena; Bravo, Jorge; Gutarra, Abel; Gabriel, Erika

2007-01-01

In this work we study the changes induced on the structure of a smectite clay by chemical acid activation with HCl using X-ray diffractometry (XRD) and transmission Moessbauer spectroscopy (TMS) techniques. By XRD we were able to determine the mineralogical composition of the clay samples and measure the changes in the interplanar distance associated to the structural modifications in the clays. We measured a reduction in the interplanar distance and reflection intensity as the acid concentration in the activation process increased. TMS allowed us identify and characterize the structural sites occupied by ferric and ferrous iron cations. In addition, we were able to monitor the effects caused by the chemical acid activation on the valence state of the iron cations that occupy these structural sites in the clay. For the treatment at low acid concentration, keeping time and temperature of activation constant, our results showed a strong effect on the ferrous and ferric iron sites, reducing and increasing their adsorption relative areas respectively.

Quantitative mixture fraction measurements in combustion system via laser induced breakdown spectroscopy

KAUST Repository

Mansour, Mohy S.

2015-01-01

Laser induced breakdown spectroscopy (LIBS) technique has been applied to quantitative mixture fraction measurements in flames. The measured spectra of different mixtures of natural gas and air are used to obtain the calibration parameters for local elemental mass fraction measurements and hence calculate the mixture fraction. The results are compared with the mixture fraction calculations based on the ratios of the spectral lines of H/N elements, H/O elements and C/(N+O) and they show good agreement within the reaction zone of the flames. Some deviations are observed outside the reaction zone. The ability of LIBS technique as a tool for quantitative mixture fraction as well as elemental fraction measurements in reacting and non-reacting of turbulent flames is feasible. © 2014 Elsevier Ltd. All rights reserved.

Measurement of erosion rate by absorption spectroscopy in a Hall thruster

International Nuclear Information System (INIS)

Yamamoto, Naoji; Yokota, Shigeru; Matsui, Makoto; Komurasaki, Kimiya; Arakawa, Yoshihiro

2005-01-01

The erosion rate of a Hall thruster was estimated with the objective of building a real-time erosion rate monitoring system using a 1 kW class anode layer type Hall thruster. This system aids the understanding of the tradeoff between lifetime and performance. To estimate the flux of the sputtered wall material, the number density of the sputtered iron was measured by laser absorption spectroscopy using an absorption line from ground atomic iron at 371.9935 nm. An ultravioletAl x In y Ga (1-x-y) N diode laser was used as the probe. The estimated number density of iron was 1.1x10 16 m -3 , which is reasonable when compared with that measured by duration erosion tests. The relation between estimated erosion rate and magnetic flux density also agreed with that measured by duration erosion tests

Improved Iris Recognition through Fusion of Hamming Distance and Fragile Bit Distance.

Science.gov (United States)

Hollingsworth, Karen P; Bowyer, Kevin W; Flynn, Patrick J

2011-12-01

The most common iris biometric algorithm represents the texture of an iris using a binary iris code. Not all bits in an iris code are equally consistent. A bit is deemed fragile if its value changes across iris codes created from different images of the same iris. Previous research has shown that iris recognition performance can be improved by masking these fragile bits. Rather than ignoring fragile bits completely, we consider what beneficial information can be obtained from the fragile bits. We find that the locations of fragile bits tend to be consistent across different iris codes of the same eye. We present a metric, called the fragile bit distance, which quantitatively measures the coincidence of the fragile bit patterns in two iris codes. We find that score fusion of fragile bit distance and Hamming distance works better for recognition than Hamming distance alone. To our knowledge, this is the first and only work to use the coincidence of fragile bit locations to improve the accuracy of matches.

Connecting long distance: semantic distance in analogical reasoning modulates frontopolar cortex activity.

Science.gov (United States)

Green, Adam E; Kraemer, David J M; Fugelsang, Jonathan A; Gray, Jeremy R; Dunbar, Kevin N

2010-01-01

Solving problems often requires seeing new connections between concepts or events that seemed unrelated at first. Innovative solutions of this kind depend on analogical reasoning, a relational reasoning process that involves mapping similarities between concepts. Brain-based evidence has implicated the frontal pole of the brain as important for analogical mapping. Separately, cognitive research has identified semantic distance as a key characteristic of the kind of analogical mapping that can support innovation (i.e., identifying similarities across greater semantic distance reveals connections that support more innovative solutions and models). However, the neural substrates of semantically distant analogical mapping are not well understood. Here, we used functional magnetic resonance imaging (fMRI) to measure brain activity during an analogical reasoning task, in which we parametrically varied the semantic distance between the items in the analogies. Semantic distance was derived quantitatively from latent semantic analysis. Across 23 participants, activity in an a priori region of interest (ROI) in left frontopolar cortex covaried parametrically with increasing semantic distance, even after removing effects of task difficulty. This ROI was centered on a functional peak that we previously associated with analogical mapping. To our knowledge, these data represent a first empirical characterization of how the brain mediates semantically distant analogical mapping.

EDUCATEE'S THESAURUS AS AN OBJECT OF MEASURING LEARNED MATERIAL OF THE DISTANCE LEARNING COURSE

Directory of Open Access Journals (Sweden)

Alexander Aleksandrovich RYBANOV

2013-10-01

Full Text Available Monitoring and control over the process of studying the distance learning course are based on solving the problem of making out an adequate integral mark to the educatee for mastering entire study course, by testing results. It is suggested to use the degree of correspondence between educatee's thesaurus and the study course thesaurus as an integral mark for the degree of mastering the distance learning course. Study course thesaurus is a set of the course objects with relations between them specified. The article considers metrics of the study course thesaurus complexity, made on the basis of the graph theory and the information theory. It is suggested to use the amount of information contained in the study course thesaurus graph as the metrics of the study course thesaurus complexity. Educatee's thesaurus is considered as an object of measuring educational material learned at the semantic level and is assessed on the basis of amount of information contained in its graph, taking into account the factors of learning the thesaurus objects.

Direct measurements of neutral density depletion by two-photon absorption laser-induced fluorescence spectroscopy

International Nuclear Information System (INIS)

Aanesland, A.; Liard, L.; Leray, G.; Jolly, J.; Chabert, P.

2007-01-01

The ground state density of xenon atoms has been measured by spatially resolved laser-induced fluorescence spectroscopy with two-photon excitation in the diffusion chamber of a magnetized Helicon plasma. This technique allows the authors to directly measure the relative variations of the xenon atom density without any assumptions. A significant neutral gas density depletion was measured in the core of the magnetized plasma, in agreement with previous theoretical and experimental works. It was also found that the neutral gas density was depleted near the radial walls

MEASUREMENT OF AMMONIA EMISSIONS FROM MECHANICALLY VENTILATED POULTRY HOUSES USING MULTIPATH TUNABLE DIODE LASER SPECTROSCOPY

Science.gov (United States)

Ammonia emissions from mechanically ventilated poultry operations are an important environmental concern. Open Path Tunable Diode Laser Absorption Spectroscopy has emerged as a robust real-time method for gas phase measurement of ammonia concentrations in agricultural settings. ...

Laser induced breakdown spectroscopy of the uranium including calcium. Time resolved measurement spectroscopic analysis (Contract research)

International Nuclear Information System (INIS)

Akaoka, Katsuaki; Maruyama, Youichiro; Oba, Masaki; Miyabe, Masabumi; Otobe, Haruyoshi; Wakaida, Ikuo

2010-05-01

For the remote analysis of low DF TRU (Decontamination Factor Transuranic) fuel, Laser Breakdown Spectroscopy (LIBS) was applied to uranium oxide including a small amount of calcium oxide. The characteristics, such as spectrum intensity and plasma excitation temperature, were measured using time-resolved spectroscopy. As a result, in order to obtain the stable intensity of calcium spectrum for the uranium spectrum, it was found out that the optimum observation delay time of spectrum is 4 microseconds or more after laser irradiation. (author)

Memory properties and charge effect study in Si nanocrystals by scanning capacitance microscopy and spectroscopy

Directory of Open Access Journals (Sweden)

Bassani Franck

2011-01-01

Full Text Available Abstract In this letter, isolated Si nanocrystal has been formed by dewetting process with a thin silicon dioxide layer on top. Scanning capacitance microscopy and spectroscopy were used to study the memory properties and charge effect in the Si nanocrystal in ambient temperature. The retention time of trapped charges injected by different direct current (DC bias were evaluated and compared. By ramp process, strong hysteresis window was observed. The DC spectra curve shift direction and distance was observed differently for quantitative measurements. Holes or electrons can be separately injected into these Si-ncs and the capacitance changes caused by these trapped charges can be easily detected by scanning capacitance microscopy/spectroscopy at the nanometer scale. This study is very useful for nanocrystal charge trap memory application.

VCSEL-based sensors for distance and velocity

Science.gov (United States)

Moench, Holger; Carpaij, Mark; Gerlach, Philipp; Gronenborn, Stephan; Gudde, Ralph; Hellmig, Jochen; Kolb, Johanna; van der Lee, Alexander

2016-03-01

VCSEL based sensors can measure distance and velocity in three dimensional space and are already produced in high quantities for professional and consumer applications. Several physical principles are used: VCSELs are applied as infrared illumination for surveillance cameras. High power arrays combined with imaging optics provide a uniform illumination of scenes up to a distance of several hundred meters. Time-of-flight methods use a pulsed VCSEL as light source, either with strong single pulses at low duty cycle or with pulse trains. Because of the sensitivity to background light and the strong decrease of the signal with distance several Watts of laser power are needed at a distance of up to 100m. VCSEL arrays enable power scaling and can provide very short pulses at higher power density. Applications range from extended functions in a smartphone over industrial sensors up to automotive LIDAR for driver assistance and autonomous driving. Self-mixing interference works with coherent laser photons scattered back into the cavity. It is therefore insensitive to environmental light. The method is used to measure target velocity and distance with very high accuracy at distances up to one meter. Single-mode VCSELs with integrated photodiode and grating stabilized polarization enable very compact and cost effective products. Besides the well know application as computer input device new applications with even higher accuracy or for speed over ground measurement in automobiles and up to 250km/h are investigated. All measurement methods exploit the known VCSEL properties like robustness, stability over temperature and the potential for packages with integrated optics and electronics. This makes VCSEL sensors ideally suited for new mass applications in consumer and automotive markets.

Distance of Sample Measurement Points to Prototype Catalog Curve

DEFF Research Database (Denmark)

Hjorth, Poul G.; Karamehmedovic, Mirza; Perram, John

2006-01-01

We discuss strategies for comparing discrete data points to a catalog (reference) curve by means of the Euclidean distance from each point to the curve in a pump's head H vs. flow Qdiagram. In particular we find that a method currently in use is inaccurate. We propose several alternatives...

Spectroscopy with cold and ultra-cold neutrons

Directory of Open Access Journals (Sweden)

Abele Hartmut

2015-01-01

Full Text Available We present two new types of spectroscopy methods for cold and ultra-cold neutrons. The first method, which uses the R×B drift effect to disperse charged particles in a uniformly curved magnetic field, allows to study neutron β-decay. We aim for a precision on the 10−4 level. The second method that we refer to as gravity resonance spectroscopy (GRS allows to test Newton’s gravity law at short distances. At the level of precision we are able to provide constraints on any possible gravity-like interaction. In particular, limits on dark energy chameleon fields are improved by several orders of magnitude.

INTERPRETING THE DISTANCE CORRELATION RESULTS FOR THE COMBO-17 SURVEY

International Nuclear Information System (INIS)

Richards, Mercedes T.; Richards, Donald St. P.; Martínez-Gómez, Elizabeth

2014-01-01

The accurate classification of galaxies in large-sample astrophysical databases of galaxy clusters depends sensitively on the ability to distinguish between morphological types, especially at higher redshifts. This capability can be enhanced through a new statistical measure of association and correlation, called the distance correlation coefficient, which has more statistical power to detect associations than does the classical Pearson measure of linear relationships between two variables. The distance correlation measure offers a more precise alternative to the classical measure since it is capable of detecting nonlinear relationships that may appear in astrophysical applications. We showed recently that the comparison between the distance and Pearson correlation coefficients can be used effectively to isolate potential outliers in various galaxy data sets, and this comparison has the ability to confirm the level of accuracy associated with the data. In this work, we elucidate the advantages of distance correlation when applied to large databases. We illustrate how the distance correlation measure can be used effectively as a tool to confirm nonlinear relationships between various variables in the COMBO-17 database, including the lengths of the major and minor axes, and the alternative redshift distribution. For these outlier pairs, the distance correlation coefficient is routinely higher than the Pearson coefficient since it is easier to detect nonlinear relationships with distance correlation. The V-shaped scatter plots of Pearson versus distance correlation coefficients also reveal the patterns with increasing redshift and the contributions of different galaxy types within each redshift range

Broadband cavity-enhanced absorption spectroscopy in the ultraviolet spectral region for measurements of nitrogen dioxide and formaldehyde

Science.gov (United States)

Washenfelder, R. A.; Attwood, A. R.; Flores, J. M.; Zarzana, K. J.; Rudich, Y.; Brown, S. S.

2016-01-01

Formaldehyde (CH2O) is the most abundant aldehyde in the atmosphere, and it strongly affects photochemistry through its photolysis. We describe simultaneous measurements of CH2O and nitrogen dioxide (NO2) using broadband cavity-enhanced absorption spectroscopy in the ultraviolet spectral region. The light source consists of a continuous-wave diode laser focused into a Xenon bulb to produce a plasma that emits high-intensity, broadband light. The plasma discharge is optically filtered and coupled into a 1 m optical cavity. The reflectivity of the cavity mirrors is 0.99930 ± 0.00003 (1- reflectivity = 700 ppm loss) at 338 nm, as determined from the known Rayleigh scattering of He and zero air. This mirror reflectivity corresponds to an effective path length of 1.43 km within the 1 m cell. We measure the cavity output over the 315-350 nm spectral region using a grating monochromator and charge-coupled device array detector. We use published reference spectra with spectral fitting software to simultaneously retrieve CH2O and NO2 concentrations. Independent measurements of NO2 standard additions by broadband cavity-enhanced absorption spectroscopy and cavity ring-down spectroscopy agree within 2 % (slope for linear fit = 1.02 ± 0.03 with r2 = 0.998). Standard additions of CH2O measured by broadband cavity-enhanced absorption spectroscopy and calculated based on flow dilution are also well correlated, with r2 = 0.9998. During constant mixed additions of NO2 and CH2O, the 30 s measurement precisions (1σ) of the current configuration were 140 and 210 pptv, respectively. The current 1 min detection limit for extinction measurements at 315-350 nm provides sufficient sensitivity for measurement of trace gases in laboratory experiments and ground-based field experiments. Additionally, the instrument provides highly accurate, spectroscopically based trace gas detection that may complement higher precision techniques based on non-absolute detection methods. In addition to

Mechanisms of ultrafast fluorescence depletion spectroscopy and applications to measure slovation dynamics of coummarin 153 in methanol

International Nuclear Information System (INIS)

Yang Songqiu; Liu Jianyong; Zhou Panwang; Chen Junsheng; Han Keli; He Guozhong

2012-01-01

Subpicosecond fluorescence depletion spectroscopy (FDS) was used to measure the solvation dynamics of coumarin 153 (C153) in methanol. The FDS mechanisms were discussed. A quasi-continuous model was used to describe the solvational relaxation of excited states. The perturbations of the probe pulse on the excited sample system, including up-conversion and stimulated emission, were sufficiently discussed. For a probe molecule used in the FDS experiment, ensuring that the up-conversion perturbation can be negligible is important. FDS was found to be a good technique for measuring the solvation dynamics of C153 in methanol. - Highlights: ► Mechanisms of subpicosecond fluorescence depletion spectroscopy. ► Quasi-continuous model was used to describe the solvational relaxation. ► The solvation dynamics of coumarin 153 in methanol has been measured.

COMPLIS: COllinear spectroscopy Measurements using a Pulsed Laser Ion Source

CERN Multimedia

2002-01-01

A Pulsed Laser spectroscopy experiment has been installed for the study of hyperfine structure and isotope shift of refractory and daughter elements from ISOLDE beams. It includes decelerated ion-implantation, element-selective laser ionization, magnetic and time-of-flight mass separation. The laser spectroscopy has been performed on the desorbed atoms in a set-up at ISOLDE-3 but later on high resolution laser collinear spectroscopy with the secondary pulsed ion beam is planned for the Booster ISOLDE set-up. During the first operation time of ISOLDE-3 we restricted our experiments to Doppler-limited resonant ionization laser and $\\gamma$-$\\gamma$ nuclear spectroscopy on neutron deficient platinum isotopes of even mass number down to A~=~186 and A~=~179 respectively. These isotopes have been produced by implantation of radioactive Hg and their subsequent $\\beta$-decay.

A distance measurement between specific sites on the cytoplasmic surface of bovine rhodopsin in rod outer segment disk membranes.

Science.gov (United States)

Albert, A D; Watts, A; Spooner, P; Groebner, G; Young, J; Yeagle, P L

1997-08-14

Structural information on mammalian integral membrane proteins is scarce. As part of work on an alternative approach to the structure of bovine rhodopsin, a method was devised to obtain an intramolecular distance between two specific sites on rhodopsin while in the rod outer segment disk membrane. In this report, the distance between the rhodopsin kinase phosphorylation site(s) on the carboxyl terminal and the top of the third transmembrane helix was measured on native rhodopsin. Rhodopsin was labeled with a nuclear spin label (31P) by limited phosphorylation with rhodopsin kinase. Major phosphorylation occurs at serines 343 and 338 on the carboxyl terminal. The phosphorylated rhodopsin was then specifically labeled on cysteine 140 with an electron spin label. Magic angle spinning 31P-nuclear magnetic resonance revealed the resonance arising from the phosphorylated protein. The enhancement of the transverse relaxation of this resonance by the paramagnetic spin label was observed. The strength of this perturbation was used to determine the through-space distance between the phosphorylation site(s) and the spin label position. A distance of 18 +/- 3 A was obtained.

Measurements of vitamin B12 in human blood serum using resonance Raman spectroscopy

Science.gov (United States)

Tsiminis, G.; Schartner, E. P.; Brooks, J. L.; Hutchinson, M. R.

2016-12-01

Vitamin B12 (cobalamin and its derivatives) deficiency has been identified as a potential modifiable risk factor for dementia and Alzheimer's disease. Chronic deficiency of vitamin B12 has been significantly associated with an increased risk of cognitive decline. An effective and efficient method for measuring vitamin B12 concentration in human blood would enable ongoing tracking and assessment of this potential modifiable risk factor. In this work we present an optical sensor based on resonance Raman spectroscopy for rapid measurements of vitamin B12 in human blood serum. The measurement takes less than a minute and requires minimum preparation (centrifuging) of the collected blood samples.

Infrared diode laser spectroscopy of lithium hydride

International Nuclear Information System (INIS)

Yamada, C.; Hirota, E.

1988-01-01

The fundamental and hot bands of the vibration--rotation transitions of 6 LiH, 7 LiH, 6 LiD, and 7 LiD were observed by infrared diode laser spectroscopy at Doppler-limited resolution. Lithium hydride molecules were produced by the reaction of the Li vapor with hydrogen at elevated temperatures. Some 40 transitions were observed and, after combined with submillimeter-wave spectra reported by G. M. Plummer et al. [J. Chem. Phys. 81, 4893 (1984)], were analyzed to yield Dunham-type constants with accuracies more than an order of magnitude higher than those published in the literature. It was clearly demonstrated that the Born--Oppenheimer approximation did not hold, and some parameters representing the breakdown were evaluated. The Born--Oppenheimer internuclear distance r/sup BO//sub e/ was derived to be 1.594 914 26 (59) A, where a new value of Planck's constant recommended by CODATA was employed. The relative intensity of absorption lines was measured to determine the ratio of the permanent dipole moment to its first derivative with respect to the internuclear distance: μ/sub e/ [(partialμpartialr)/sub e/ r/sub e/ ] = 1.743(86). The pressure broadening parameter Δν/sub p/ P was determined to be 6.40 (22) MHzTorr by measuring the linewidth dependence on the pressure of hydrogen, which was about four times larger than the value for the dipole--quadrupole interaction estimated by Kiefer and Bushkovitch's theory

Development of nondestructive sorting method for brown bloody eggs using VIS/NIR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Lee, Hong Seock; Kim, Dae Yong; Kandpal, Lalit Mohan; Lee, Sang Dae; Cho, Byoung Kwan [Dept. of Biosystems Machinery Engineering, College of Agriculture and Life Science, Chungnam National University, Daejeon (Korea, Republic of); Mo, Chang Yeun; Hong, Soon Jung [Rural Development Administration, Jeonju (Korea, Republic of)

2014-02-15

The aim of this study was the non-destructive evaluation of bloody eggs using VIS/NIR spectroscopy. The bloody egg samples used to develop the sorting mode were produced by injecting chicken blood into the edges of egg yolks. Blood amounts of 0.1, 0.7, 0.04, and 0.01 mL were used for the bloody egg samples. The wavelength range for the VIS/NIR spectroscopy was 471 to 1154 nm, and the spectral resolution was 1.5nm. For the measurement system, the position of the light source was set to, and the distance between the light source and samples was set to 100 mm. The minimum exposure time of the light source was set to 30 ms to ensure the fast sorting of bloody eggs and prevent heating damage of the egg samples. Partial least squares-discriminant analysis (PLS-DA) was used for the spectral data obtained from VIS/NIR spectroscopy. The classification accuracies of the sorting models developed with blood samples of 0.1, 0.07, 0.04, and 0.01 mL were 97.9%, 98.9%, 94.8%, and 86.45%, respectively. In this study, a novel nondestructive sorting technique was developed to detect bloody brown eggs using spectral data obtained from VIS/NIR spectroscopy.

Comparing alternative approaches to measuring the geographical accessibility of urban health services: Distance types and aggregation-error issues

OpenAIRE

Riva Mylène; Abdelmajid Mohamed; Apparicio Philippe; Shearmur Richard

2008-01-01

Abstract Background Over the past two decades, geographical accessibility of urban resources for population living in residential areas has received an increased focus in urban health studies. Operationalising and computing geographical accessibility measures depend on a set of four parameters, namely definition of residential areas, a method of aggregation, a measure of accessibility, and a type of distance. Yet, the choice of these parameters may potentially generate different results leadi...

'Beam-emission spectroscopy' diagnostics also measure edge fast-ion light

International Nuclear Information System (INIS)

Heidbrink, W W; Bortolon, A; McKee, G R; Smith, D R

2011-01-01

Beam-emission spectroscopy (BES) diagnostics normally detect fluctuations in the light emitted by an injected neutral beam. Under some circumstances, however, light from fast ions that charge exchange in the high neutral-density region at the edge of the plasma make appreciable contributions to the BES signals. This 'passive' fast-ion D α (FIDA) light appears in BES signals from both the DIII-D tokamak and the National Spherical Torus Experiment (NSTX). One type of passive FIDA light is associated with classical orbits that traverse the edge. Another type is caused by instabilities that expel fast ions from the core; this light can complicate measurement of the instability eigenfunction.

Long distance elementary measurement of the radiation dose ratio produced by neutron activation

International Nuclear Information System (INIS)

Zhou Changgeng; Lou Benchao; Wu Chunlei; Hu Yonghong; Li Yan

2009-04-01

The working principle and the structure and performances of a long distance controllable individual radiation dose ratio instrument are described. The radiation dose ratio produced by neutron activation is elementarily measured by using this instrument in the neutron generator hall with high neutron yield. When neutron yield arrives to 2 x 10 11 s -1 , the radiation dose ratio produced by neutron activation is 99.9 μSv/h in 1 h after the generator being stopped. The radiation dose ratio is reduced to 24.4 μSv/h in 39 h after the generator being stopped. When neutron yield is 3.2 x 10 10 s -1 , the radiation dose ratio produced by neutron activation is 21.9 μSv/h in 36 min, after the generator being stopped. The measurement results may provide reference for physical experimenters and neutron generator operators. (authors)

The Next Generation Virgo Cluster Survey (NGVS). XVIII. Measurement and Calibration of Surface Brightness Fluctuation Distances for Bright Galaxies in Virgo (and Beyond)

Science.gov (United States)

Cantiello, Michele; Blakeslee, John P.; Ferrarese, Laura; Côté, Patrick; Roediger, Joel C.; Raimondo, Gabriella; Peng, Eric W.; Gwyn, Stephen; Durrell, Patrick R.; Cuillandre, Jean-Charles

2018-04-01

We describe a program to measure surface brightness fluctuation (SBF) distances to galaxies observed in the Next Generation Virgo Cluster Survey (NGVS), a photometric imaging survey covering 104 deg2 of the Virgo cluster in the u*, g, i, and z bandpasses with the Canada–France–Hawaii Telescope. We describe the selection of the sample galaxies, the procedures for measuring the apparent i-band SBF magnitude {\\overline{m}}i, and the calibration of the absolute Mibar as a function of observed stellar population properties. The multiband NGVS data set provides multiple options for calibrating the SBF distances, and we explore various calibrations involving individual color indices as well as combinations of two different colors. Within the color range of the present sample, the two-color calibrations do not significantly improve the scatter with respect to wide-baseline, single-color calibrations involving u*. We adopt the ({u}* -z) calibration as a reference for the present galaxy sample, with an observed scatter of 0.11 mag. For a few cases that lack good u* photometry, we use an alternative relation based on a combination of (g-i) and (g-z) colors, with only a slightly larger observed scatter of 0.12 mag. The agreement of our measurements with the best existing distance estimates provides confidence that our measurements are accurate. We present a preliminary catalog of distances for 89 galaxies brighter than B T ≈ 13.0 mag within the survey footprint, including members of the background M and W Clouds at roughly twice the distance of the main body of the Virgo cluster. The extension of the present work to fainter and bluer galaxies is in progress.

The reliability of Raman micro-spectroscopy in measuring the density of CO2 mantle fluids

Science.gov (United States)

Remigi, S.; Frezzotti, M. L.; Ferrando, S.; Villa, I. M.; Maffeis, A.

2017-12-01

Recent evaluations of carbon fluxes into and out the Earth's interior recognize that a significant part of the total outgassing of deep Earth carbon occurs in tectonically active areas (Kelemen and Manning, 2015). Potential tracers of carbon fluxes at mantle depths include CO2 fluid inclusions in peridotites. Raman micro-spectroscopy allows calculating the density of CO2 fluids based on the distance of the CO2 Fermi doublet, Δ, in cm-1 (Rosso and Bodnar, 1995). The aim of this work is to check the reliability of Raman densimeter equations (cf. Lamadrid et al., 2016) for high-density CO2 fluids originating at mantle depths. Forty pure CO2 inclusions in peridotites (El Hierro, Canary Islands) of known density (microthermometry) have been analyzed by Raman micro-spectroscopy. In order to evaluate the influence of contaminants on the reliability of equations, 22 CO2-rich inclusions containing subordinate amounts of N2, CO, SO2 have also been studied. Raman spectrometer analytical conditions are: 532 nm laser, 80 mW emission power, T 18°C, 1800 and 600 grating, 1 accumulation x 80 sec. Daily calibration included diamond and atmosphere N2. Results suggest that the "Raman densimeter" represents an accurate method to calculate the density of CO2 mantle fluids. Equations, however, must be applied only to pure CO2 fluids, since contaminants, even in trace amounts (0.39 mol%), affect the Δ resulting in density overestimation. Present study further highlights how analytical conditions and data processing, such as spectral resolution (i.e., grating), calibration linearity, and statistical treatment of spectra, influence the accuracy and the precision of Δ measurements. As a consequence, specific analytical protocols for single Raman spectrometers should be set up in order to get reliable CO2 density data. Kelemen, Peter B., & Craig E. Manning. PNAS, 112.30 (2015): E3997-E4006.Lamadrid, H. M., Moore, L. R., Moncada, D., Rimstidt, J. D., Burruss, R. C., & Bodnar, R. J. Chem

Fabrication of 94Zr thin target for recoil distance doppler shift method of lifetime measurement

International Nuclear Information System (INIS)

Gupta, C.K.; Rohilla, Aman; Abhilash, S.R.; Kabiraj, D.; Singh, R.P.; Mehta, D.; Chamoli, S.K.

2014-01-01

A thin isotopic 94 Zr target of thickness 520μg/cm 2 has been prepared for recoil distance Doppler shift method (RDM) lifetime measurement by using an electron beam deposition method on tantalum backing of 3.5 mg/cm 2 thickness at Inter University Accelerator Center (IUAC), New Delhi. To meet the special requirement of smoothness of surface for RDM lifetime measurement and also to protect the outer layer of 94 Zr from peeling off, a very thin layer of gold has been evaporated on a 94 Zr target on a specially designed substrate holder. In all, 143 mg of 99.6% enriched 94 Zr target material was utilized for the fabrication of 94 Zr targets. The target has been successfully used in a recent RDM lifetime measurement experiment at IUAC

Fabrication of 94Zr thin target for recoil distance doppler shift method of lifetime measurement

Science.gov (United States)

Gupta, C. K.; Rohilla, Aman; Abhilash, S. R.; Kabiraj, D.; Singh, R. P.; Mehta, D.; Chamoli, S. K.

2014-11-01

A thin isotopic 94Zr target of thickness 520 μg /cm2 has been prepared for recoil distance Doppler shift method (RDM) lifetime measurement by using an electron beam deposition method on tantalum backing of 3.5 mg/cm2 thickness at Inter University Accelerator Center (IUAC), New Delhi. To meet the special requirement of smoothness of surface for RDM lifetime measurement and also to protect the outer layer of 94Zr from peeling off, a very thin layer of gold has been evaporated on a 94Zr target on a specially designed substrate holder. In all, 143 mg of 99.6% enriched 94Zr target material was utilized for the fabrication of 94Zr targets. The target has been successfully used in a recent RDM lifetime measurement experiment at IUAC.

The impact of inverse photoemission spectroscopy measurements on regioregular poly(3-hexylthiophene) films

International Nuclear Information System (INIS)

Li, Zhi; Schlaf, Rudy; Sun, Siqi; Li, Xiao

2014-01-01

Inverse photoemission spectroscopy (IPES) enables the characterization of the density of states of unoccupied energy states above the Fermi level. However, due to the relatively high electron currents required to achieve useful signal to noise ratios, sample damage is a concern. Regioregular poly(3-hexylthiophene) (rr-P3HT) was used to systematically study the influence of electron radiation during IPES measurements on a prototypical conductive polymer. A series of IPES measurements exposing the samples to a range of electron fluxes was performed. An analysis of the electronic structure and the morphology showed that significant changes occurred in the investigated samples depending on the electron flux. X-ray diffraction results revealed that the root cause of the spectral changes is most likely related to crystallization of the film in an edge-on orientation. This was confirmed by Raman spectroscopy where both the C-C and C=C stretch modes shifted to lower frequencies after 5 IPES scans indicating a more ordered molecular structure. The observation of these stretch modes even after exposure to higher electron flux indicates that the main chemical structure of the P3HT molecules remains mostly intact during the IPES measurements. The absence of significant changes in C 1s and S 2p photoemission core level lines also confirmed this conclusion

Validation, verification and evaluation of a Train to Train Distance Measurement System by means of Colored Petri Nets

International Nuclear Information System (INIS)

Song, Haifeng; Liu, Jieyu; Schnieder, Eckehard

2017-01-01

Validation, verification and evaluation are necessary processes to assure the safety and functionality of a system before its application in practice. This paper presents a Train to Train Distance Measurement System (TTDMS), which can provide distance information independently from existing onboard equipment. Afterwards, we proposed a new process using Colored Petri Nets to verify the TTDMS system functional safety, as well as to evaluate the system performance. Three main contributions are carried out in the paper: Firstly, this paper proposes a formalized TTDMS model, and the model correctness is validated using state space analysis and simulation-based verification. Secondly, corresponding checking queries are proposed for the purpose of functional safety verification. Further, the TTDMS performance is evaluated by applying parameters in the formal model. Thirdly, the reliability of a functional prototype TTDMS is estimated. It is found that the procedure can cooperate with the system development, and both formal and simulation-based verifications are performed. Using our process to evaluate and verify a system is easier to read and more reliable compared to executable code and mathematical methods. - Highlights: • A new Train to Train Distance Measurement System. • New approach verifying system functional safety and evaluating system performance by means of CPN. • System formalization using the system property concept. • Verification of system functional safety using state space analysis. • Evaluation of system performance applying simulation-based analysis.

Protein structural studies by paramagnetic solid-state NMR spectroscopy aided by a compact cyclen-type Cu(II) binding tag

Energy Technology Data Exchange (ETDEWEB)

Sengupta, Ishita; Gao, Min; Arachchige, Rajith J.; Nadaud, Philippe S. [The Ohio State University, Department of Chemistry and Biochemistry (United States); Cunningham, Timothy F.; Saxena, Sunil [University of Pittsburgh, Department of Chemistry (United States); Schwieters, Charles D. [National Institutes of Health, Center for Information Technology (United States); Jaroniec, Christopher P., E-mail: jaroniec@chemistry.ohio-state.edu [The Ohio State University, Department of Chemistry and Biochemistry (United States)

2015-01-15

Paramagnetic relaxation enhancements (PREs) are a rich source of structural information in protein solid-state NMR spectroscopy. Here we demonstrate that PRE measurements in natively diamagnetic proteins are facilitated by a thiol-reactive compact, cyclen-based, high-affinity Cu{sup 2+} binding tag, 1-[2-(pyridin-2-yldisulfanyl)ethyl]-1,4,7,10-tetraazacyclododecane (TETAC), that overcomes the key shortcomings associated with the use of larger, more flexible metal-binding tags. Using the TETAC–Cu{sup 2+} K28C mutant of B1 immunoglobulin-binding domain of protein G as a model, we find that amino acid residues located within ∼10 Å of the Cu{sup 2+} center experience considerable transverse PREs leading to severely attenuated resonances in 2D {sup 15}N–{sup 13}C correlation spectra. For more distant residues, electron–nucleus distances are accessible via quantitative measurements of longitudinal PREs, and we demonstrate such measurements for {sup 15}N–Cu{sup 2+} distances up to ∼20 Å.

Effect of Image Linearization on Normalized Compression Distance

Science.gov (United States)

Mortensen, Jonathan; Wu, Jia Jie; Furst, Jacob; Rogers, John; Raicu, Daniela

Normalized Information Distance, based on Kolmogorov complexity, is an emerging metric for image similarity. It is approximated by the Normalized Compression Distance (NCD) which generates the relative distance between two strings by using standard compression algorithms to compare linear strings of information. This relative distance quantifies the degree of similarity between the two objects. NCD has been shown to measure similarity effectively on information which is already a string: genomic string comparisons have created accurate phylogeny trees and NCD has also been used to classify music. Currently, to find a similarity measure using NCD for images, the images must first be linearized into a string, and then compared. To understand how linearization of a 2D image affects the similarity measure, we perform four types of linearization on a subset of the Corel image database and compare each for a variety of image transformations. Our experiment shows that different linearization techniques produce statistically significant differences in NCD for identical spatial transformations.

Calibrating the Type Ia Supernova Distance Scale Using Surface Brightness Fluctuations

Science.gov (United States)

Potter, Cicely; Jensen, Joseph B.; Blakeslee, John; Milne, Peter; Garnavich, Peter M.; Brown, Peter

2018-06-01

We have observed 20 supernova host galaxies with HST WFC3/IR in the F110W filter, and prepared the data for Surface Brightness Fluctuation (SBF) distance measurements. The purpose of this study is to determine if there are any discrepancies between the SBF distance scale and the type-Ia SN distance scale, for which local calibrators are scarce. We have now measured SBF magnitudes to all early-type galaxies that have hosted SN Ia within 80 Mpc for which SBF measurements are possible. SBF is the only distance measurement technique with statistical uncertainties comparable to SN Ia that can be applied to galaxies out to 80 Mpc.

Characterisation of a micro-plasma device sensor using electrical measurements and emission spectroscopy

International Nuclear Information System (INIS)

Mariotti, D.

2002-04-01

This thesis reports on research undertaken on the characterisation of a micro-plasma device to be used for gas analysis by mean of plasma emission spectroscopy. The work covers aspects related to the micro-plasma electrical and optical emission parameters, and their importance for the utilisation of the micro-plasma device in gas analysis. Experimental results have been used to analyse the fundamental micro-plasma processes and to develop a model, which could provide additional information. This dissertation contains a general literature review of topics related to plasma physics, plasma emission spectroscopy, gas analysis (chemical analysis and artificial olfaction) and other micro-plasma applications. Experimental work focuses on two main areas: electrical measurements and emission measurements. Firstly, electrical measurements are taken and interpretations are given. Where necessary, new theoretical treatments are suggested in order to describe better the physical phenomena. Plasma emission has been considered under different working conditions. This allowed the characterisation of the micro-plasma emission and also a better understanding of the micro-plasma processes. On the basis of the experimental data obtained and other assumptions a model has been developed. A computer simulation based on this model provided additional useful information on the micro- plasma behaviour. The first fundamental implication of this new research is the peculiar behaviour of the micro-plasma. This micro-plasma exhibited deviations from Paschen law and strong dependency on cathode material, which contributed to the formation of a low current stable regime. These results have been followed by physical interpretations and theoretical descriptions. The second implication is the establishment of the boundaries and of the influencing parameters for plasma emission spectroscopy as an analytical tool in this particular micro-plasma. From the applied perspective this study has shown that

Conception and development of an optical methodology applied to long-distance measurement of suspension bridges dynamic displacement

International Nuclear Information System (INIS)

Martins, L Lages; Ribeiro, A Silva; Rebordão, J M

2013-01-01

This paper describes the conception and development of an optical system applied to suspension bridge structural monitoring, aiming real-time and long-distance measurement of dynamical three-dimensional displacement, namely, in the central section of the main span. The main innovative issues related to this optical approach are described and a comparison with other optical and non-optical measurement systems is performed. Moreover, a computational simulator tool developed for the optical system design and validation of the implemented image processing and calculation algorithms is also presented

Optical method for distance and displacement measurements of the probe-sample separation in a scanning near-field optical microscope

International Nuclear Information System (INIS)

Santamaria, L.; Siller, H. R.; Garcia-Ortiz, C. E.; Cortes, R.; Coello, V.

2016-01-01

In this work, we present an alternative optical method to determine the probe-sample separation distance in a scanning near-field optical microscope. The experimental method is based in a Lloyd’s mirror interferometer and offers a measurement precision deviation of ∼100 nm using digital image processing and numerical analysis. The technique can also be strategically combined with the characterization of piezoelectric actuators and stability evaluation of the optical system. It also opens the possibility for the development of an automatic approximation control system valid for probe-sample distances from 5 to 500 μm.

Optical method for distance and displacement measurements of the probe-sample separation in a scanning near-field optical microscope

Energy Technology Data Exchange (ETDEWEB)

Santamaria, L.; Siller, H. R. [Tecnológico de Monterrey, Eugenio Garza Sada 2501 Sur, Monterrey, N.L., 64849 (Mexico); Garcia-Ortiz, C. E., E-mail: cegarcia@cicese.mx [CONACYT Research Fellow – CICESE, Unidad Monterrey, Alianza Centro 504, Apodaca, NL, 66629 (Mexico); Cortes, R.; Coello, V. [CICESE, Unidad Monterrey, PIIT, Alianza Centro 504, Apodaca, NL, 66629 (Mexico)

2016-04-15

In this work, we present an alternative optical method to determine the probe-sample separation distance in a scanning near-field optical microscope. The experimental method is based in a Lloyd’s mirror interferometer and offers a measurement precision deviation of ∼100 nm using digital image processing and numerical analysis. The technique can also be strategically combined with the characterization of piezoelectric actuators and stability evaluation of the optical system. It also opens the possibility for the development of an automatic approximation control system valid for probe-sample distances from 5 to 500 μm.

An independent distance estimate to the AGB star R Sculptoris

Science.gov (United States)

Maercker, M.; Brunner, M.; Mecina, M.; De Beck, E.

2018-04-01

Context. Distance measurements to astronomical objects are essential for understanding their intrinsic properties. For asymptotic giant branch (AGB) stars it is particularly difficult to derive accurate distance estimates. Period-luminosity relationships rely on the correlation of different physical properties of the stars, while the angular sizes and variability of AGB stars make parallax measurements inherently inaccurate. For the carbon AGB star R Sculptoris, the uncertain distance significantly affects the interpretation of observations regarding the evolution of the stellar mass loss during and after the most recent thermal pulse. Aim. We aim to provide a new, independent measurement of the distance to R Sculptoris, reducing the absolute uncertainty of the distance estimate to this source. Methods: R Scl is a semi-regular pulsating star, surrounded by a thin shell of dust and gas created during a thermal pulse ≈2000 years ago. The stellar light is scattered by the dust particles in the shell at a radius of ≈19″. The variation in the stellar light affects the amount of dust-scattered light with the same period and amplitude ratio, but with a phase lag that depends on the absolute size of the shell. We measured this phase lag by observing the star R Scl and the dust-scattered stellar light from the shell at five epochs between June-December 2016. By observing in polarised light, we imaged the shell in the plane of the sky, removing any uncertainty due to geometrical effects. The phase lag gives the absolute size of the shell, and together with the angular size of the shell directly gives the absolute distance to R Sculptoris. Results: We measured a phase lag between the stellar variations and the variation in the shell of 40.0 ± 4.0 days. The angular size of the shell is measured to be 19.″1 ± 0.″7. Combined, this gives an absolute distance to R Sculptoris of 361 ± 44 pc. Conclusions: We independently determined the absolute distance to R Scl with

Lecture notes on: Electrical theory behind the measurement of body fluids with bioimpedance spectroscopy (BIS)

DEFF Research Database (Denmark)

Jødal, Lars

The lecture notes describe how body fluid volumes can be measured/estimated using the technique bio-impedance spectroscopy (BIS). The opening chapters assume little or none technical/mathematical knowledge and can hopefully be read by anyone interested in the techneque. Later chapters become more...

Off-axis integrated cavity output spectroscopy with a mid-infrared interband cascade laser for real-time breath ethane measurements.

Science.gov (United States)

Parameswaran, Krishnan R; Rosen, David I; Allen, Mark G; Ganz, Alan M; Risby, Terence H

2009-02-01

Cavity-enhanced tunable diode laser absorption spectroscopy is an attractive method for measuring small concentrations of gaseous species. Ethane is a breath biomarker of lipid peroxidation initiated by reactive oxygen species. A noninvasive means of quickly quantifying oxidative stress status has the potential for broad clinical application. We present a simple, compact system using off-axis integrated cavity output spectroscopy with an interband cascade laser and demonstrate its use in real-time measurements of breath ethane. We demonstrate a detection sensitivity of 0.48 ppb/Hz(1/2).

Photothermal modulation of the gap distance in scanning tunneling microscopy

International Nuclear Information System (INIS)

Amer, N.M.; Skumanich, A.; Ripple, D.

1986-01-01

We have employed the photothermal effect to modulate the gap distance in a tunneling microscope. In this approach, optical heating induces the expansion and buckling of laser-illuminated sample surface. The surface displacement can be modulated over a wide frequency range, and its height (typically <1 A-circle) can be varied by changing the illumination intensity and modulation frequency. This novel method provides an alternative means for performing tunneling spectroscopy and microscopy, and for determining work functions of materials

The Concept of Distance in International Management Research

DEFF Research Database (Denmark)

Ambos, Björn; Håkanson, Lars

2014-01-01

The effect of distance on firms' performance when entering, operating in and across foreign markets is a central issue in international management. However, our understanding of the impact of distance has long been constrained by flawed conceptualizations and unreliable measures. The papers...... in this issue break new ground both by advancing our theoretical understanding and by introducing new and potentially more useful measures. In this introduction, we provide a brief overview of the evolution of the distance concept before introducing the individual papers. We end by offering observations...... for future research based on the issues they raise....

Laser spectroscopy used in nuclear physics; La spectroscopie laser appliquee a la physique nucleaire

Energy Technology Data Exchange (ETDEWEB)

Le Blanc, F

2001-04-05

The study of nuclear shapes is a basic topic since it constitutes an excellent ground for testing and validating nuclear models. Measurements of the electron quadrupolar moment, of the nuclear charge radius and of the magnetic dipolar moment shed light on the nuclear deformation. Laser spectroscopy is a specific tool for such measurements, it is based on the interaction of the nucleus with the surrounding electron cloud (hyperfine structure), it is then an external approach of the shape of the nucleus whereas the classical nuclear spectroscopy ({alpha}, {beta} or {gamma}) gives information on the deformation from the inside of the nucleus. The author describes 2 techniques of laser spectroscopy: the colinear spectroscopy directly applied to a beam issued from an isotope separator and the resonant ionization spectroscopy linked with atom desorption that allows the study of particular nuclei. In order to illustrate both methods some effective measurements are presented: - the colinear spectroscopy has allowed the achievement of the complete description of the isomeric state (T = 31 years) of hafnium-178; - The experiment Complis has revealed an unexpected even-odd zigzag effect on very neutron-deficient platinum isotopes; and - the comparison of 2 isotopes of gold and platinum with their isomers has shown that the inversion of 2 levels of neutron, that was found out by nuclear spectroscopy, is in fact a consequence of a change in the nuclear shape. (A.C.)

Multi-image acquisition-based distance sensor using agile laser spot beam.

Science.gov (United States)

Riza, Nabeel A; Amin, M Junaid

2014-09-01

We present a novel laser-based distance measurement technique that uses multiple-image-based spatial processing to enable distance measurements. Compared with the first-generation distance sensor using spatial processing, the modified sensor is no longer hindered by the classic Rayleigh axial resolution limit for the propagating laser beam at its minimum beam waist location. The proposed high-resolution distance sensor design uses an electronically controlled variable focus lens (ECVFL) in combination with an optical imaging device, such as a charged-coupled device (CCD), to produce and capture different laser spot size images on a target with these beam spot sizes different from the minimal spot size possible at this target distance. By exploiting the unique relationship of the target located spot sizes with the varying ECVFL focal length for each target distance, the proposed distance sensor can compute the target distance with a distance measurement resolution better than the axial resolution via the Rayleigh resolution criterion. Using a 30 mW 633 nm He-Ne laser coupled with an electromagnetically actuated liquid ECVFL, along with a 20 cm focal length bias lens, and using five spot images captured per target position by a CCD-based Nikon camera, a proof-of-concept proposed distance sensor is successfully implemented in the laboratory over target ranges from 10 to 100 cm with a demonstrated sub-cm axial resolution, which is better than the axial Rayleigh resolution limit at these target distances. Applications for the proposed potentially cost-effective distance sensor are diverse and include industrial inspection and measurement and 3D object shape mapping and imaging.

Language distance and tree reconstruction

International Nuclear Information System (INIS)

Petroni, Filippo; Serva, Maurizio

2008-01-01

Languages evolve over time according to a process in which reproduction, mutation and extinction are all possible. This is very similar to haploid evolution for asexual organisms and for the mitochondrial DNA of complex ones. Exploiting this similarity, it is possible, in principle, to verify hypotheses concerning the relationship among languages and to reconstruct their family tree. The key point is the definition of the distances among pairs of languages in analogy with the genetic distances among pairs of organisms. Distances can be evaluated by comparing grammar and/or vocabulary, but while it is difficult, if not impossible, to quantify grammar distance, it is possible to measure a distance from vocabulary differences. The method used by glottochronology computes distances from the percentage of shared 'cognates', which are words with a common historical origin. The weak point of this method is that subjective judgment plays a significant role. Here we define the distance of two languages by considering a renormalized edit distance among words with the same meaning and averaging over the two hundred words contained in a Swadesh list. In our approach the vocabulary of a language is the analogue of DNA for organisms. The advantage is that we avoid subjectivity and, furthermore, reproducibility of results is guaranteed. We apply our method to the Indo-European and the Austronesian groups, considering, in both cases, fifty different languages. The two trees obtained are, in many respects, similar to those found by glottochronologists, with some important differences as regards the positions of a few languages. In order to support these different results we separately analyze the structure of the distances of these languages with respect to all the others

Language distance and tree reconstruction

Science.gov (United States)

Petroni, Filippo; Serva, Maurizio

2008-08-01

Languages evolve over time according to a process in which reproduction, mutation and extinction are all possible. This is very similar to haploid evolution for asexual organisms and for the mitochondrial DNA of complex ones. Exploiting this similarity, it is possible, in principle, to verify hypotheses concerning the relationship among languages and to reconstruct their family tree. The key point is the definition of the distances among pairs of languages in analogy with the genetic distances among pairs of organisms. Distances can be evaluated by comparing grammar and/or vocabulary, but while it is difficult, if not impossible, to quantify grammar distance, it is possible to measure a distance from vocabulary differences. The method used by glottochronology computes distances from the percentage of shared 'cognates', which are words with a common historical origin. The weak point of this method is that subjective judgment plays a significant role. Here we define the distance of two languages by considering a renormalized edit distance among words with the same meaning and averaging over the two hundred words contained in a Swadesh list. In our approach the vocabulary of a language is the analogue of DNA for organisms. The advantage is that we avoid subjectivity and, furthermore, reproducibility of results is guaranteed. We apply our method to the Indo-European and the Austronesian groups, considering, in both cases, fifty different languages. The two trees obtained are, in many respects, similar to those found by glottochronologists, with some important differences as regards the positions of a few languages. In order to support these different results we separately analyze the structure of the distances of these languages with respect to all the others.

Photoacoustic infrared spectroscopy for conducting gas tracer tests and measuring water saturations in landfills

International Nuclear Information System (INIS)

Jung, Yoojin; Han, Byunghyun; Mostafid, M. Erfan; Chiu, Pei; Yazdani, Ramin; Imhoff, Paul T.

2012-01-01

Highlights: ► Photoacoustic infrared spectroscopy tested for measuring tracer gas in landfills. ► Measurement errors for tracer gases were 1–3% in landfill gas. ► Background signals from landfill gas result in elevated limits of detection. ► Technique is much less expensive and easier to use than GC. - Abstract: Gas tracer tests can be used to determine gas flow patterns within landfills, quantify volatile contaminant residence time, and measure water within refuse. While gas chromatography (GC) has been traditionally used to analyze gas tracers in refuse, photoacoustic spectroscopy (PAS) might allow real-time measurements with reduced personnel costs and greater mobility and ease of use. Laboratory and field experiments were conducted to evaluate the efficacy of PAS for conducting gas tracer tests in landfills. Two tracer gases, difluoromethane (DFM) and sulfur hexafluoride (SF 6 ), were measured with a commercial PAS instrument. Relative measurement errors were invariant with tracer concentration but influenced by background gas: errors were 1–3% in landfill gas but 4–5% in air. Two partitioning gas tracer tests were conducted in an aerobic landfill, and limits of detection (LODs) were 3–4 times larger for DFM with PAS versus GC due to temporal changes in background signals. While higher LODs can be compensated by injecting larger tracer mass, changes in background signals increased the uncertainty in measured water saturations by up to 25% over comparable GC methods. PAS has distinct advantages over GC with respect to personnel costs and ease of use, although for field applications GC analyses of select samples are recommended to quantify instrument interferences.

Laser spectroscopy of radioactive beams

International Nuclear Information System (INIS)

Otten, E.W.

1983-01-01

The problem of using the laser spectroscopy in investigations radioactive beams is considered. The main attention is payed to the isotope shift of nuclear charge radii delta 2 >. The general trend of delta 2 > is discussed. Predictions for delta>r 2 < in the framework of the droplet model are given. It is noted that two parameter interpretation of the isotope shift based on the droplet model works the better, the further the distance spans and the clearer the nuclear structure is

Hyperfine Structure Measurements of Antiprotonic $^3$He using Microwave Spectroscopy

CERN Document Server

Friedreich, Susanne

The goal of this project was to measure the hyperfine structure of $\\overline{\\text{p}}^3$He$^+$ using the technique of laser-microwave-laser spectroscopy. Antiprotonic helium ($\\overline{\\text{p}}$He$^+$) is a neutral exotic atom, consisting of a helium nucleus, an electron and an antiproton. The interactions of the angular momenta of its constituents cause a hyperfine splitting ({HFS}) within the energy states of this new atom. The 3\\% of formed antiprotonic helium atoms which remain in a metastable, radiative decay-dominated state have a lifetime of about 1-3~$\\mu$s. This time window is used to do spectroscopic studies. The hyperfine structure of $\\overline{\\text{p}}^4$He$^+$ was already extensively investigated before. From these measurements the spin magnetic moment of the antiproton can be determined. A comparison of the result to the proton magnetic moment provides a test of {CPT} invariance. Due to its higher complexity the new exotic three-body system of $\\overline{\\text{p}}^3$He$^+$ is a cross-check...

Measurement Errors Arising When Using Distances in Microeconometric Modelling and the Individuals’ Position Is Geo-Masked for Confidentiality

Directory of Open Access Journals (Sweden)

Giuseppe Arbia

2015-10-01

Full Text Available In many microeconometric models we use distances. For instance, in modelling the individual behavior in labor economics or in health studies, the distance from a relevant point of interest (such as a hospital or a workplace is often used as a predictor in a regression framework. However, in order to preserve confidentiality, spatial micro-data are often geo-masked, thus reducing their quality and dramatically distorting the inferential conclusions. In particular in this case, a measurement error is introduced in the independent variable which negatively affects the properties of the estimators. This paper studies these negative effects, discusses their consequences, and suggests possible interpretations and directions to data producers, end users, and practitioners.

Measurement of rumen dry matter and neutral detergent fiber degradability of feeds by Fourier-transform infrared spectroscopy

DEFF Research Database (Denmark)

Belanche, A.; Weisbjerg, Martin Riis; Allison, G.G.

2014-01-01

This study explored the potential of partial least squares (PLS) and Fourier-transform infrared spectroscopy (FTIR) to predict rumen dry matter (DM) and neutral detergent fiber (NDF) degradation parameters of a wide range of feeds for ruminants, as an alternative to the in situ method. In total...... components, such as cellulose, pectin, lignin, cutin, and suberin, but also with nonstructural carbohydrates and certain active compounds. In conclusion, FTIR spectroscopy could be considered a low-cost alternative to in situ measurements in feed evaluation....

Application of the dose rate spectroscopy to the dose-to-curie conversion method using a NaI(Tl) detector

International Nuclear Information System (INIS)

JI, Young-Yong; Chung, Kun Ho; Kim, Chang-Jong; Kang, Mun Ja; Park, Sang Tae

2015-01-01

Dose rate spectroscopy is a very useful method to directly calculate the individual dose rate from the converted energy spectrum for the dose rate using the G-factor which is related to the used detector response function. A DTC conversion method for the estimation of the radioactivity based on the measured dose rate from the radioactive materials can then be modified into a simple equation using the dose rate spectroscopy. In order to make the method validation of the modified DTC conversion method, experimental verifications using a 3″φx3″ NaI(Tl) detector were conducted at the simple geometry of the point source located onto a detector and more complex geometries which mean the assay of the simulated radioactive material. In addition, the linearity about the results from the modified DTC conversion method was also estimated by increasing the distance between source positions and a detector to confirm the method validation in the energy, dose rate, and distance range of the gamma nuclides. - Highlights: • A modified DTC conversion method using the dose rate spectroscopy was established. • In-situ calibration factors were calculated from the MCNP simulation. • Radioactivities of the disk sources were accurately calculated using a modified DTC conversion method. • A modified DTC conversion method was applied to the assay of the radioactive material

A simple method of measuring tibial tubercle to trochlear groove distance on MRI: description of a novel and reliable technique.

Science.gov (United States)

Camp, Christopher L; Heidenreich, Mark J; Dahm, Diane L; Bond, Jeffrey R; Collins, Mark S; Krych, Aaron J

2016-03-01

Tibial tubercle-trochlear groove (TT-TG) distance is a variable that helps guide surgical decision-making in patients with patellar instability. The purpose of this study was to compare the accuracy and reliability of an MRI TT-TG measuring technique using a simple external alignment method to a previously validated gold standard technique that requires advanced software read by radiologists. TT-TG was calculated by MRI on 59 knees with a clinical diagnosis of patellar instability in a blinded and randomized fashion by two musculoskeletal radiologists using advanced software and by two orthopaedists using the study technique which utilizes measurements taken on a simple electronic imaging platform. Interrater reliability between the two radiologists and the two orthopaedists and intermethods reliability between the two techniques were calculated using interclass correlation coefficients (ICC) and concordance correlation coefficients (CCC). ICC and CCC values greater than 0.75 were considered to represent excellent agreement. The mean TT-TG distance was 14.7 mm (Standard Deviation (SD) 4.87 mm) and 15.4 mm (SD 5.41) as measured by the radiologists and orthopaedists, respectively. Excellent interobserver agreement was noted between the radiologists (ICC 0.941; CCC 0.941), the orthopaedists (ICC 0.978; CCC 0.976), and the two techniques (ICC 0.941; CCC 0.933). The simple TT-TG distance measurement technique analysed in this study resulted in excellent agreement and reliability as compared to the gold standard technique. This method can predictably be performed by orthopaedic surgeons without advanced radiologic software. II.

Admittance spectroscopy or deep level transient spectroscopy: A contrasting juxtaposition

Science.gov (United States)

Bollmann, Joachim; Venter, Andre

2018-04-01

A comprehensive understanding of defects in semiconductors remains of primary importance. In this paper the effectiveness of two of the most commonly used semiconductor defect spectroscopy techniques, viz. deep level transient spectroscopy (DLTS) and admittance spectroscopy (AS) are reviewed. The analysis of defects present in commercially available SiC diodes shows that admittance spectroscopy allows the identification of deep traps with reduced measurement effort compared to deep Level Transient Spectroscopy (DLTS). Besides the N-donor, well-studied intrinsic defects were detected in these diodes. Determination of their activation energy and defect density, using the two techniques, confirm that the sensitivity of AS is comparable to that of DLTS while, due to its well defined peak shape, the spectroscopic resolution is superior. Additionally, admittance spectroscopy can analyze faster emission processes which make the study of shallow defects more practical and even that of shallow dopant levels, possible. A comparative summary for the relevant spectroscopic features of the two capacitance methods are presented.

Influence of the intergonial distance on image distortion in panoramic radiographs.

Science.gov (United States)

Ladeira, D B S; Cruz, A D; Almeida, S M; Bóscolo, F N

2012-07-01

The aim of this study was to evaluate the influence of the intergonial distance during the formation of panoramic radiographic images by means of horizontal and vertical measurements. 30 macerated mandibles were categorized into 3 different groups (n = 10) according to their intergonial distances as follows: G1, mean distance 8.2 cm, G2, mean distance 9.0 cm and G3, mean distance 9.6 cm. Three metal spheres 0.198 cm in diameter and placed at an incline using an isosceles triangle were separately placed over the internal and external surfaces of the mandibles before radiographic exposure for the purpose of taking the horizontal and vertical measurements. The occlusal planes of the mandibles were horizontally placed on the chin rest of the panoramic machine Orthopantomograph® OP 100 (Instrumentarium Imaging, Tuusula, Finland) and were then radiographed. In the panoramic radiographs, an expert radiologist measured the distances between the metal spheres in the horizontal and vertical directions using a digital caliper. The data were tabled and statistically analysed by Student's t-test and analysis of variance with Tukey post-test (α = 0.05). In all three groups magnification of the distances between spheres was observed when compared with the real distance in both horizontal and vertical measurements (p 0.05). Differences between horizontal and vertical measurements were observed in different regions in all evaluated groups (p image formation in the panoramic radiograph.

Grasland Stable Isotope Flux Measurements: Three Isotopomers of Carbon Dioxide Measured by QCL Spectroscopy