Science.gov

Sample records for cross-spectrum experimental method

  1. Experimental Physics - Modern Methods

    NASA Astrophysics Data System (ADS)

    Dunlap, R. A.

    1988-10-01

    Designed for physics students treating the underlying basis for modern techniques and the devices used, this timely survey describes current experimental methods in a clear and accessible text. This up-to-date volume provides an essential part of undergraduate physics training; until now, students were often expected to learn many of these methods in the laboratory without proper introduction. The broad coverage of available techniques includes discussion of state-of-the-art electronic equipment, as well as such topics as discrete semiconductor devices, signal processing, thermometry, optical components, nuclear instrumentation, and x-ray diffraction methods. Professor Dunlap's text will serve not only as a complete introduction for majors but also as a reference work for technicians throughout a professional career. In addition to tutorial discussions presented, tables of numerical data and constants are included, further enhancing the book as a permanent reference.

  2. Measurement of the cross spectrum of HF electrostatic waves in an auroral plasma

    NASA Astrophysics Data System (ADS)

    Pottelette, R.; Illiano, J. M.

    1983-06-01

    A method for the metrology of space plasmas, based on the reception of electrostatic waves by a pair of small dipole antennas was tested in PORCUPINE project rocket experiments. Both dipoles received signals from the natural electrostatic microfield in the plasma; the cross spectrum of these random signals was measured. Data obtained during a weak auroral activity are presented. Natural electrostatic emissions were observed around the upper hybrid frequency and also around the three-halves harmonic of the electron gyrofrequency. A linear calculation shows that the amplitudes of these emissions are above the thermal noise level of the plasma. To explain the observations, it is necessary to take into account the presence of low-energy precipitating electrons (1 to 20 eV), which are highly anisotropic.

  3. The cluster-galaxy cross spectrum. An additional probe of cosmological and halo parameters

    NASA Astrophysics Data System (ADS)

    Hütsi, G.; Lahav, O.

    2008-12-01

    Context: There are several wide field galaxy and cluster surveys planned for the near future, e.g. BOSS, WFMOS, ADEPT, Hetdex, SPT, eROSITA. In the simplest approach, one would analyze these independently, thus neglecting the extra information provided by the cluster-galaxy cross pairs. Aims: In this paper we have focused on the possible synergy between these surveys by investigating the amount of information encoded in the cross pairs. Methods: We present a model for the cluster-galaxy cross spectrum within the halo model framework. To assess the gain in performance due to inclusion of the cluster-galaxy cross pairs, we carry out a Fisher matrix analysis for a BOSS-like galaxy redshift survey targeting luminous red galaxies and a hypothetical mass-limited cluster redshift survey with a lower mass threshold of 1.7 × 1014 h-1 M⊙ over the same volume. Results: On small scales, a cluster-galaxy cross spectrum directly probes the density profile of the halos, instead of the density profile convolved with itself, as is the case for the galaxy power spectrum. Due to this different behavior, adding information from the cross pairs helps to tighten constraints on the halo occupation distribution (e.g. a factor of ~2 compression of the error ellipses on the m_glow-α plane) and offers an alternative mechanism compared with techniques that directly fit halo density profiles. By inclusion of the cross pairs, a factor of ~2 stronger constraints are obtained for σ_8, while the improvement for the dark energy figure-of-merit is somewhat weaker: an increase by a factor of 1.4. We have also written down the formalism for the case when only photometric redshifts are available for both the clusters and the galaxies. For the analysis of the photometric surveys the inclusion of the cluster-galaxy cross pairs might be very beneficial since the photo-z errors for the clusters are usually significantly smaller than for the typical galaxies.

  4. Experimental methods for identifying failure mechanisms

    NASA Technical Reports Server (NTRS)

    Daniel, I. M.

    1983-01-01

    Experimental methods for identifying failure mechanisms in fibrous composites are studied. Methods to identify failure in composite materials includes interferometry, holography, fractography and ultrasonics.

  5. Interferometric spectropolarimetry: alternate experimental methods.

    PubMed

    Fymat, A L

    1972-10-01

    Three alternate methods of obtaining spectra of the intensity and state of polarization of light are proposed. The methods make use of a two-beam amplitude division interferometer using the technique of Fourier spectroscopy. They can be applied to either emerging beam, source beam, or detector beam r to both. They do not require the presence of polarizers in the arms of the instrument. In one method (Method 2) a single analyzer is used in front of the detector with three successive orientations of its transmission axis azimuth (0 degrees , 45 degrees , 90 degrees ). In another method (Method 3) a (linear) polarizer assuming the same set of orientations is placed in the incident beam. A third method (Method 4), a hybrid of the former two methods, makes use of both a polarizer and an analyzer in the locations indicated. The latter method presents itself three alternate possibilities. Method 2 permits the determination of all four Stokes parameters of polarization, whereas Methods 3 and 4 cannot yield the ellipticity parameter. All methods require the recording of three interferograms. However, two interferograms can provide the intensity and degree of polarization in any of the methods described. The theory of our earlier method (Method 1, Fymat and Abhyankar, 1970) is also established more rigorously concerning the proposed interferometric arrangements, the applicability of the method to the source beam, and the possibility of deriving the orientation of the plane of polarization and the ellipticity from a single interferogram.

  6. Interferometric spectropolarimetry - Alternate experimental methods.

    NASA Technical Reports Server (NTRS)

    Fymat, A. L.

    1972-01-01

    Three alternate methods of obtaining spectra of the intensity and state of polarization of light are proposed. The methods make use of a two-beam amplitude division interferometer using the technique of Fourier spectroscopy. They do not require the presence of polarizers in the arms of the instrument. In one method a single analyzer is used in front of the detector with three successive orientations of its transmission axis azimuth. In another method, a (linear) polarizer assuming the same set of orientations is placed in the incident beam. A third method, a hybrid of the former two methods, makes use of both a polarizer and analyzer in the locations indicated. The first method permits the determination of all four Stokes parameters of polarization, whereas the other two methods cannot yield the ellipticity parameter. All methods require the recording of three interferograms. However, two interferograms can provide the intensity and degree of polarization in any of the methods described.

  7. Significance tests for the wavelet cross spectrum and wavelet linear coherence

    NASA Astrophysics Data System (ADS)

    Ge, Z.

    2008-12-01

    This work attempts to develop significance tests for the wavelet cross spectrum and the wavelet linear coherence as a follow-up study on Ge (2007). Conventional approaches that are used by Torrence and Compo (1998) based on stationary background noise time series were used here in estimating the sampling distributions of the wavelet cross spectrum and the wavelet linear coherence. The sampling distributions are then used for establishing significance levels for these two wavelet-based quantities. In addition to these two wavelet quantities, properties of the phase angle of the wavelet cross spectrum of, or the phase difference between, two Gaussian white noise series are discussed. It is found that the tangent of the principal part of the phase angle approximately has a standard Cauchy distribution and the phase angle is uniformly distributed, which makes it impossible to establish significance levels for the phase angle. The simulated signals clearly show that, when there is no linear relation between the two analysed signals, the phase angle disperses into the entire range of [-π,π] with fairly high probabilities for values close to ±π to occur. Conversely, when linear relations are present, the phase angle of the wavelet cross spectrum settles around an associated value with considerably reduced fluctuations. When two signals are linearly coupled, their wavelet linear coherence will attain values close to one. The significance test of the wavelet linear coherence can therefore be used to complement the inspection of the phase angle of the wavelet cross spectrum. The developed significance tests are also applied to actual data sets, simultaneously recorded wind speed and wave elevation series measured from a NOAA buoy on Lake Michigan. Significance levels of the wavelet cross spectrum and the wavelet linear coherence between the winds and the waves reasonably separated meaningful peaks from those generated by randomness in the data set. As with simulated

  8. Gaseous Sulfate Solubility in Glass: Experimental Method

    SciTech Connect

    Bliss, Mary

    2013-11-30

    Sulfate solubility in glass is a key parameter in many commercial glasses and nuclear waste glasses. This report summarizes key publications specific to sulfate solubility experimental methods and the underlying physical chemistry calculations. The published methods and experimental data are used to verify the calculations in this report and are expanded to a range of current technical interest. The calculations and experimental methods described in this report will guide several experiments on sulfate solubility and saturation for the Hanford Waste Treatment Plant Enhanced Waste Glass Models effort. There are several tables of sulfate gas equilibrium values at high temperature to guide experimental gas mixing and to achieve desired SO3 levels. This report also describes the necessary equipment and best practices to perform sulfate saturation experiments for molten glasses. Results and findings will be published when experimental work is finished and this report is validated from the data obtained.

  9. Experimental design methods for bioengineering applications.

    PubMed

    Keskin Gündoğdu, Tuğba; Deniz, İrem; Çalışkan, Gülizar; Şahin, Erdem Sefa; Azbar, Nuri

    2016-01-01

    Experimental design is a form of process analysis in which certain factors are selected to obtain the desired responses of interest. It may also be used for the determination of the effects of various independent factors on a dependent factor. The bioengineering discipline includes many different areas of scientific interest, and each study area is affected and governed by many different factors. Briefly analyzing the important factors and selecting an experimental design for optimization are very effective tools for the design of any bioprocess under question. This review summarizes experimental design methods that can be used to investigate various factors relating to bioengineering processes. The experimental methods generally used in bioengineering are as follows: full factorial design, fractional factorial design, Plackett-Burman design, Taguchi design, Box-Behnken design and central composite design. These design methods are briefly introduced, and then the application of these design methods to study different bioengineering processes is analyzed.

  10. Using Experimental Methods in Higher Education Research

    ERIC Educational Resources Information Center

    Ross, Steven M.; Morrison, Gary R.; Lowther, Deborah L.

    2005-01-01

    Experimental methods have been used extensively for many years to conduct research in education and psychology. However, applications of experiments to investigate technology and other instructional innovations in higher education settings have been relatively limited. The present paper examines ways in which experiments can be used productively…

  11. A method for experimental modal separation

    NASA Technical Reports Server (NTRS)

    Hallauer, W. L., Jr.

    1977-01-01

    A method is described for the numerical simulation of multiple-shaker modal survey testing using simulated experimental data to optimize the shaker force-amplitude distribution for the purpose of isolating individual modes of vibration. Inertia, damping, stiffness, and model data are stored on magnetic disks, available by direct access to the interactive FORTRAN programs which perform all computations required by this relative force amplitude distribution method.

  12. Experimental validation of structural optimization methods

    NASA Technical Reports Server (NTRS)

    Adelman, Howard M.

    1992-01-01

    The topic of validating structural optimization methods by use of experimental results is addressed. The need for validating the methods as a way of effecting a greater and an accelerated acceptance of formal optimization methods by practicing engineering designers is described. The range of validation strategies is defined which includes comparison of optimization results with more traditional design approaches, establishing the accuracy of analyses used, and finally experimental validation of the optimization results. Examples of the use of experimental results to validate optimization techniques are described. The examples include experimental validation of the following: optimum design of a trussed beam; combined control-structure design of a cable-supported beam simulating an actively controlled space structure; minimum weight design of a beam with frequency constraints; minimization of the vibration response of helicopter rotor blade; minimum weight design of a turbine blade disk; aeroelastic optimization of an aircraft vertical fin; airfoil shape optimization for drag minimization; optimization of the shape of a hole in a plate for stress minimization; optimization to minimize beam dynamic response; and structural optimization of a low vibration helicopter rotor.

  13. Time evolution of surface chlorophyll patterns from cross-spectrum analysis of satellite color images

    NASA Technical Reports Server (NTRS)

    Denman, Kenneth L.; Abbott, Mark R.

    1988-01-01

    The rate of decorrelation of surface chlorophyll patterns as a function of the time separation between pairs of images was determined from two sequences of CZCS images of the Pacific Ocean area adjacent to Vancouver Island, Canada; cloud-free subareas were selected that were common to several images separated in time by 1-17 days. Image pairs were subjected to two-dimensional autospectrum and cross-spectrum analysis in an array processor, and squared coherence estimates found for several wave bands were plotted against time separation, in analogy with a time-lagged cross correlation function. It was found that, for wavelengths of 50-150 km, significant coherence was lost after 7-10 days, while for wavelengths of 25-50 km, significant coherence was lost after only 5-7 days. In both cases, offshore regions maintained coherence longer than coastal regions.

  14. Experimental methods in studying child language acquisition.

    PubMed

    Ambridge, Ben; Rowland, Caroline F

    2013-03-01

    This article reviews the some of the most widely used methods used for studying children's language acquisition including (1) spontaneous/naturalistic, diary, parental report data, (2) production methods (elicited production, repetition/elicited imitation, syntactic priming/weird word order), (3) comprehension methods (act-out, pointing, intermodal preferential looking, looking while listening, conditioned head turn preference procedure, functional neuroimaging) and (4) judgment methods (grammaticality/acceptability judgments, yes-no/truth-value judgments). The review outlines the types of studies and age-groups to which each method is most suited, as well as the advantage and disadvantages of each. We conclude by summarising the particular methodological considerations that apply to each paradigm and to experimental design more generally. These include (1) choosing an age-appropriate task that makes communicative sense (2) motivating children to co-operate, (3) choosing a between-/within-subjects design, (4) the use of novel items (e.g., novel verbs), (5) fillers, (6) blocked, counterbalanced and random presentation, (7) the appropriate number of trials and participants, (8) drop-out rates (9) the importance of control conditions, (10) choosing a sensitive dependent measure (11) classification of responses, and (12) using an appropriate statistical test. WIREs Cogn Sci 2013, 4:149-168. doi: 10.1002/wcs.1215 For further resources related to this article, please visit the WIREs website. The authors declare no conflict of interest. Copyright © 2013 John Wiley & Sons, Ltd.

  15. Experimental methods in compressor noise studies

    NASA Astrophysics Data System (ADS)

    Lewy, S.; Jubelin, B.

    Rotating blade machines are a very important source of aeronautical noise. The present investigation is concerned with studies of noise generated by axial compressors, taking into account aircraft jet engines. The introduction of high bypass ratio engines for subsonic transportation led to a very pronounced improvement in performance and, in addition, also to a significant decrease in jet noise. The fan has now become the primary noise source. The theoretical background of compressor noise studies is examined, taking into account the resolution of the wave equation in a guided medium, the cut-off properties of a duct, azimuthal modes generated by a rotating source, and consequences of the theoretical model. The sound emission upstream of a compressor at subsonic and transonic speeds is considered along with details regarding the experimental methods suited to the study of compressor noise.

  16. Experimental test of airplane boarding methods

    DOE PAGES

    Steffen, Jason H.; Hotchkiss, Jon

    2011-10-26

    We report the results of an experimental comparison of different airplane boarding methods. This test was conducted in a mock 757 fuselage, located on a Southern California soundstage, with 12 rows of six seats and a single aisle. Five methods were tested using 72 passengers of various ages. We found a significant reduction in the boarding times of optimized methods over traditional methods. These improved methods, if properly implemented, could result in a significant savings to airline companies. The process of boarding an airplane is of interest to a variety of groups. The public is interested both as a curiosity,more » as it is something that they may regularly experience, and as a consumer, as their experiences good or bad can affect their loyalties. Airline companies and their employees also have a stake in an efficient boarding procedure as time saved in the boarding process may result is monetary savings, in the quality of interactions with passengers, and in the application of human resources to the general process of preparing an airplane for departure. A recent study (Nyquist and McFadden, 2008) indicates that the average cost to an airline company for each minute of time spent at the terminal is roughly $30. Thus, each minute saved in the turn-around time of a flight has the potential to generate over $16,000,000 in annual savings (assuming an average of 1500 flights per day). While the boarding process may not be the primary source of delay in returning an airplane to the skies, reducing the boarding time may effectively eliminate passenger boarding as a contributor in any meaningful measure. Consequently, subsequent efforts to streamline the other necessary tasks, such as refueling and maintenance, would be rewarded with a material reduction in time at the gate for each flight.« less

  17. Experimental test of airplane boarding methods

    SciTech Connect

    Steffen, Jason H.; Hotchkiss, Jon

    2011-10-26

    We report the results of an experimental comparison of different airplane boarding methods. This test was conducted in a mock 757 fuselage, located on a Southern California soundstage, with 12 rows of six seats and a single aisle. Five methods were tested using 72 passengers of various ages. We found a significant reduction in the boarding times of optimized methods over traditional methods. These improved methods, if properly implemented, could result in a significant savings to airline companies. The process of boarding an airplane is of interest to a variety of groups. The public is interested both as a curiosity, as it is something that they may regularly experience, and as a consumer, as their experiences good or bad can affect their loyalties. Airline companies and their employees also have a stake in an efficient boarding procedure as time saved in the boarding process may result is monetary savings, in the quality of interactions with passengers, and in the application of human resources to the general process of preparing an airplane for departure. A recent study (Nyquist and McFadden, 2008) indicates that the average cost to an airline company for each minute of time spent at the terminal is roughly $30. Thus, each minute saved in the turn-around time of a flight has the potential to generate over $16,000,000 in annual savings (assuming an average of 1500 flights per day). While the boarding process may not be the primary source of delay in returning an airplane to the skies, reducing the boarding time may effectively eliminate passenger boarding as a contributor in any meaningful measure. Consequently, subsequent efforts to streamline the other necessary tasks, such as refueling and maintenance, would be rewarded with a material reduction in time at the gate for each flight.

  18. FUNDAMENTAL AREAS OF PHENOMENOLOGY (INCLUDING APPLICATIONS): Wavelet Cross-Spectrum Analysis of Multi-Scale Disturbance Instability and Transition on Sharp Cone Hypersonic Boundary Layer

    NASA Astrophysics Data System (ADS)

    Han, Jian; Jiang, Nan

    2008-05-01

    Experimental measurement of hypersonic boundary layer stability and transition on a sharp cone with a half angle of 5° is carried out at free-coming stream Mach number 6 in a hypersonic wind tunnel. Mean and fluctuation surface-thermal-flux characteristics of the hypersonic boundary layer flow are measured by Pt-thin-film thermocouple temperature sensors installed at 28 stations on the cone surface along longitudinal direction. At hypersonic speeds, the dominant flow instabilities demonstrate that the growth rate of the second mode tends to exceed that of the low-frequency mode. Wavelet-based cross-spectrum technique is introduced to obtain the multi-scale cross-spectral characteristics of the fluctuating signals in the frequency range of the second mode. Nonlinear interactions both of the second mode disturbance and the first mode disturbance are demonstrated to be dominant instabilities in the initial stage of laminar-turbulence transition for hypersonic shear flow.

  19. Experimental characterization of composites. [load test methods

    NASA Technical Reports Server (NTRS)

    Bert, C. W.

    1975-01-01

    The experimental characterization for composite materials is generally more complicated than for ordinary homogeneous, isotropic materials because composites behave in a much more complex fashion, due to macroscopic anisotropic effects and lamination effects. Problems concerning the static uniaxial tension test for composite materials are considered along with approaches for conducting static uniaxial compression tests and static uniaxial bending tests. Studies of static shear properties are discussed, taking into account in-plane shear, twisting shear, and thickness shear. Attention is given to static multiaxial loading, systematized experimental programs for the complete characterization of static properties, and dynamic properties.

  20. Experimental methods for geological remote sensing

    NASA Technical Reports Server (NTRS)

    Vincent, R. K.

    1972-01-01

    During the past year a two channel IR technique for discrimination among silicate rocks was tested for a second time, a three channel IR method was tested for the first time, and a new visible-reflective IR ratio method was hypothesized and qualitatively tested for iron oxide recognition. Both the two channel and three channel IR ratios methods were capable of discriminating felsic from mafic rock types. The three-channel ratio values measured by the scanner were found to agree, within reasonable limits, with the values of R calculated from laboratory data. The capability of the three channel method to obtain absolute ratios is accompanied by a costly processing routine. The two channel technique is superior for low thermal contrast scenes about which some ground truth is available because of its speed and economy.

  1. Experimental and analysis methods in radiochemical experiments

    NASA Astrophysics Data System (ADS)

    Cattadori, C. M.; Pandola, L.

    2016-04-01

    Radiochemical experiments made the history of neutrino physics by achieving the first observation of solar neutrinos (Cl experiment) and the first detection of the fundamental pp solar neutrinos component (Ga experiments). They measured along decades the integral νe charged current interaction rate in the exposed target. The basic operation principle is the chemical separation of the few atoms of the new chemical species produced by the neutrino interactions from the rest of the target, and their individual counting in a low-background counter. The smallness of the expected interaction rate (1 event per day in a ˜ 100 ton target) poses severe experimental challenges on the chemical and on the counting procedures. The main aspects related to the analysis techniques employed in solar neutrino experiments are reviewed and described, with a special focus given to the event selection and the statistical data treatment.

  2. Learning by Experimentation: The Operator Refinement Method

    DTIC Science & Technology

    1987-10-30

    1, in; ", ll ~ t In ’it . - 1 1rn ttuuuuc 1Sr 11l , 1. Introduction: The Need for Reactive Experimentation Learning in the context, of prohlerm solving...8217)1. 11 0 itt tii i wlthed r’r it’ h e \\ Nzn in!?’ ’iýws dit a l i t ol (1, ll il lij.t d’ I n A ow 1o , U11 w "’-blvw h w0 "Plŕ ýýfli,~li in H Ill-d M...dowill ciaj th iy , wuo s’ pctcsi~~ st’,; ll ~IC ie er& to kn’t W l )fl 1nn11i 0es Oan i an ins 14ltlý as welt ats h~lis~n"ci onl ). lrh nis perforiln The l

  3. Experimental Mathemataics: Examples, Methods andImplications

    SciTech Connect

    Bailey, David H.; Borwein, Jonathan M.

    2005-01-31

    Recent years have seen the flowering of ''experimental'' mathematics, namely the utilization of modern computer technology as an active tool in mathematical research. This development is not limited to a handful of researchers, nor to a handful of universities, nor is it limited to one particular field of mathematics. Instead, it involves hundreds of individuals, at many different institutions, who have turned to the remarkable new computational tools now available to assist in their research, whether it be in number theory, algebra, analysis, geometry or even topology. These tools are being used to work out specific examples, generate plots, perform various algebraic and calculus manipulations, test conjectures, and explore routes to formal proof. Using computer tools to test conjectures is by itself a major time saver for mathematicians, as it permits them to quickly rule out false notions.

  4. Autonomous Experimentation of Carbon Nanotube Using Response Surface Methods

    DTIC Science & Technology

    2015-03-26

    copyright protection in the United States. AFIT-ENS-MS-15-M-113 AUTOMONOUS EXPERIMENTATION OF CARBON NANOTUBE GROWTH USING RESPONSE SURFACE...UNLIMITED. AFIT-ENS-MS-15-M-113 AUTOMONOUS EXPERIMENTATION OF CARBON NANOTUBE GROWTH USING RESPONSE SURFACE METHODS William Adorno III, BS...Laboratory (AFRL) utilizes the Adaptive Rapid Experimentation and Spectroscopy (ARES) system to synthesize carbon nanotubes . The AFRL researchers

  5. Two MIS Analysis Methods: An Experimental Comparison.

    ERIC Educational Resources Information Center

    Wang, Shouhong

    1996-01-01

    In China, 24 undergraduate business students applied data flow diagrams (DFD) to a mini-case, and 20 used object-oriented analysis (OOA). DFD seemed easier to learn, but after training, those using the OOA method for systems analysis made fewer errors. (SK)

  6. An Experimental Method for Semantic Field Study.

    ERIC Educational Resources Information Center

    Cutler, Anne

    This paper emphasizes the need for empirical research and objective discovery procedures in semantics, and illustrates a method by which these goals may be obtained. The aim of the methodology described is to provide a description of the internal structure of a semantic field by eliciting the description--in an objective, standardized manner--from…

  7. Two MIS Analysis Methods: An Experimental Comparison.

    ERIC Educational Resources Information Center

    Wang, Shouhong

    1996-01-01

    In China, 24 undergraduate business students applied data flow diagrams (DFD) to a mini-case, and 20 used object-oriented analysis (OOA). DFD seemed easier to learn, but after training, those using the OOA method for systems analysis made fewer errors. (SK)

  8. An experimental unification of reservoir computing methods.

    PubMed

    Verstraeten, D; Schrauwen, B; D'Haene, M; Stroobandt, D

    2007-04-01

    Three different uses of a recurrent neural network (RNN) as a reservoir that is not trained but instead read out by a simple external classification layer have been described in the literature: Liquid State Machines (LSMs), Echo State Networks (ESNs) and the Backpropagation Decorrelation (BPDC) learning rule. Individual descriptions of these techniques exist, but a overview is still lacking. Here, we present a series of experimental results that compares all three implementations, and draw conclusions about the relation between a broad range of reservoir parameters and network dynamics, memory, node complexity and performance on a variety of benchmark tests with different characteristics. Next, we introduce a new measure for the reservoir dynamics based on Lyapunov exponents. Unlike previous measures in the literature, this measure is dependent on the dynamics of the reservoir in response to the inputs, and in the cases we tried, it indicates an optimal value for the global scaling of the weight matrix, irrespective of the standard measures. We also describe the Reservoir Computing Toolbox that was used for these experiments, which implements all the types of Reservoir Computing and allows the easy simulation of a wide range of reservoir topologies for a number of benchmarks.

  9. Statistical Manual. Methods of Making Experimental Inferences

    DTIC Science & Technology

    1951-06-01

    statistical procedures. The body of the manual presents each procedure in "cook-book" style, first in general outline, then in illustration . The... illustrations are drawn in the main from the engineering sciences, though it is recognized that many of the methods originated in other fields. This work...significant error. To illustrate in terms of the simple experiment of the inclined plane: a) if an error greater than 0.040 seconds is significant, but

  10. La Methode Experimentale en Pedagogie (The Experimental Method in Pedagogy)

    ERIC Educational Resources Information Center

    Rouquette, Michel-Louis

    1975-01-01

    The pedagogue is caught between the qualitative and quantitative or regularized aspects of his work, a situation not automatically conducive to scientific study. The article refreshes the instructor on the elementary principles of experimentation: observation, systematization, elaboration of hypothesis, and startegies of comparison. (Text is in…

  11. Acquisition of Psychomotor Skills in Dentistry: An Experimental Teaching Method.

    ERIC Educational Resources Information Center

    Vann, William F., Jr.; And Others

    1981-01-01

    A traditional method of teaching psychomotor skills in a preclinical restorative dentistry laboratory course was compared with an experimental method. The experimental group was taught using a guided systematic approach that relied on detailed checklists and exhaustive faculty feedback. (Author/MLW)

  12. A Laboratory That Reveals Indirect Experimental Methods of Science

    ERIC Educational Resources Information Center

    Schmidt, Chris; And Others

    1975-01-01

    Describes a physics laboratory experiment for nonscience majors intended to illustrate indirect experimental methods of sciences treating objects too small for sensory observation. The student explores and attempts to identify an object in a closed container, using provided experimental tools and small openings in the opaque lid. (MLH)

  13. Methods of experimentation with models and utilization of results

    NASA Technical Reports Server (NTRS)

    Robert,

    1924-01-01

    The present report treats the subject of testing small models in a wind tunnel and of the methods employed for rendering the results constant, accurate and comparable with one another. Detailed experimental results are given.

  14. Experimental Methodology in English Teaching and Learning: Method Features, Validity Issues, and Embedded Experimental Design

    ERIC Educational Resources Information Center

    Lee, Jang Ho

    2012-01-01

    Experimental methods have played a significant role in the growth of English teaching and learning studies. The paper presented here outlines basic features of experimental design, including the manipulation of independent variables, the role and practicality of randomised controlled trials (RCTs) in educational research, and alternative methods…

  15. Experimental implementation of the modified independent modal space control method

    NASA Technical Reports Server (NTRS)

    Baz, A.; Poh, S.

    1990-01-01

    An experimental realization of a modified independent modal space control (MIMSC) method to control the vibration of a flexible cantilevered beam is presented. In its operation the method relies on the use of one piezoelectric actuator to control several vibration modes through a time-sharing strategy. The effectiveness of the MIMSC method in damping out the beam vibration is demonstrated by comparing the results with those obtained by other modal control methods. Two methods are considered, the independent modal space control method and the pseudo-inverse method. The feasibility of the MIMSC method as a viable alternative for controlling large flexible structures with a very small number of actuators is emphasized.

  16. Experimental implementation of the modified independent modal space control method

    NASA Technical Reports Server (NTRS)

    Baz, A.; Poh, S.

    1990-01-01

    An experimental realization of a modified independent modal space control (MIMSC) method to control the vibration of a flexible cantilevered beam is presented. In its operation the method relies on the use of one piezoelectric actuator to control several vibration modes through a time-sharing strategy. The effectiveness of the MIMSC method in damping out the beam vibration is demonstrated by comparing the results with those obtained by other modal control methods. Two methods are considered, the independent modal space control method and the pseudo-inverse method. The feasibility of the MIMSC method as a viable alternative for controlling large flexible structures with a very small number of actuators is emphasized.

  17. Comparison as an Approach to the Experimental Method

    ERIC Educational Resources Information Center

    Turner, David A.

    2017-01-01

    In his proposal for comparative education, Marc Antoinne Jullien de Paris argues that the comparative method offers a viable alternative to the experimental method. In an experiment, the scientist can manipulate the variables in such a way that he or she can see any possible combination of variables at will. In comparative education, or in…

  18. Theoretical and experimental methods to select aircraft handling qualities

    NASA Astrophysics Data System (ADS)

    Zaichik, L. E.; Yashin, Y. P.; Perebatov, V. S.; Desyatnik, P. A.

    2013-12-01

    A theoretical-experimental method is developed to analyze and adequately select aircraft handling qualities (HQ). A review is presented of the criteria developed by the authors to estimate the role of motion cues in controlling of an aircraft, and criteria to estimate the on-ground simulation fidelity. The method is presented to translate on-ground simulation results into real flight conditions.

  19. Taguchi method of experimental design in materials education

    NASA Technical Reports Server (NTRS)

    Weiser, Martin W.

    1993-01-01

    Some of the advantages and disadvantages of the Taguchi Method of experimental design as applied to Materials Science will be discussed. This is a fractional factorial method that employs the minimum number of experimental trials for the information obtained. The analysis is also very simple to use and teach, which is quite advantageous in the classroom. In addition, the Taguchi loss function can be easily incorporated to emphasize that improvements in reproducibility are often at least as important as optimization of the response. The disadvantages of the Taguchi Method include the fact that factor interactions are normally not accounted for, there are zero degrees of freedom if all of the possible factors are used, and randomization is normally not used to prevent environmental biasing. In spite of these disadvantages it is felt that the Taguchi Method is extremely useful for both teaching experimental design and as a research tool, as will be shown with a number of brief examples.

  20. Taguchi method of experimental design in materials education

    NASA Technical Reports Server (NTRS)

    Weiser, Martin W.

    1993-01-01

    Some of the advantages and disadvantages of the Taguchi Method of experimental design as applied to Materials Science will be discussed. This is a fractional factorial method that employs the minimum number of experimental trials for the information obtained. The analysis is also very simple to use and teach, which is quite advantageous in the classroom. In addition, the Taguchi loss function can be easily incorporated to emphasize that improvements in reproducibility are often at least as important as optimization of the response. The disadvantages of the Taguchi Method include the fact that factor interactions are normally not accounted for, there are zero degrees of freedom if all of the possible factors are used, and randomization is normally not used to prevent environmental biasing. In spite of these disadvantages it is felt that the Taguchi Method is extremely useful for both teaching experimental design and as a research tool, as will be shown with a number of brief examples.

  1. Electron scattering by molecules. II - Experimental methods and data

    NASA Technical Reports Server (NTRS)

    Trajmar, S.; Chutjian, A.; Register, D. F.

    1983-01-01

    Experimental techniques for measuring electron-molecule collision cross sections are briefly summarized. A survey of the available experimental cross section data is presented. The emphasis here is on elastic scattering, rotational, vibrational and electronic excitations, total electron scattering, and momentum transfer in the few eV to few hundred eV impact energy range. Reference is made to works concerned with high energy electron scattering, innershell and multi-electron excitations, conicidence methods and electron scattering in laser fields.

  2. Electron scattering by molecules. II - Experimental methods and data

    NASA Technical Reports Server (NTRS)

    Trajmar, S.; Chutjian, A.; Register, D. F.

    1983-01-01

    Experimental techniques for measuring electron-molecule collision cross sections are briefly summarized. A survey of the available experimental cross section data is presented. The emphasis here is on elastic scattering, rotational, vibrational and electronic excitations, total electron scattering, and momentum transfer in the few eV to few hundred eV impact energy range. Reference is made to works concerned with high energy electron scattering, innershell and multi-electron excitations, conicidence methods and electron scattering in laser fields.

  3. Experimental methods for phase equilibria at high pressures.

    PubMed

    Dohrn, Ralf; Fonseca, José M S; Peper, Stephanie

    2012-01-01

    Knowledge of high-pressure phase equilibria is crucial in many fields, e.g., for the design and optimization of high-pressure chemical and separation processes, carbon capture and storage, hydrate formation, applications of ionic liquids, and geological processes. This review presents the variety of methods to measure phase equilibria at high pressures and, following a classification, discusses the measurement principles, advantages, challenges, and error sources. Examples of application areas are given. A detailed knowledge and understanding of the different methods is fundamental not only for choosing the most suitable method for a certain task but also for the evaluation of experimental data. The discrepancy between the (sometimes low) true accuracy of published experimental data and the (high) accuracy claimed by authors is addressed. Some essential requirements for the generation of valuable experimental results are summarized.

  4. A soil irrigation method for experimental plant growth

    NASA Astrophysics Data System (ADS)

    Pop, M. N.; Soran, M. L.

    2015-12-01

    An irrigation method developed in order to ensure periodic wetting of several batches of soil, for experimental plant growth, is proposed. An experimental irrigation installation, intended to perform real-time soil moisturizing, by adding known quantities (preset for a certain batch of soil) of aqueous solutions has been built and tested. The prototype installation comprises six miniature pumps for water dosage, each meant to moisturize a batch of soil. Each pump is actuated from the mains power supply, with zero-crossing synchronization. The administrated quantity of aqueous solution is a multiple of the minimum volume, 0.2±0.01 ml of fluid. Due to its structure, the system allows the administration of different aqueous solutions for each batch of soil. Due to its modular construction the experimental installation can be expanded in order to ensure water disposal over an increased number of soil batches and the method may be suited also for micro irrigation systems.

  5. Using Propensity Score Methods to Approximate Factorial Experimental Designs

    ERIC Educational Resources Information Center

    Dong, Nianbo

    2011-01-01

    The purpose of this study is through Monte Carlo simulation to compare several propensity score methods in approximating factorial experimental design and identify best approaches in reducing bias and mean square error of parameter estimates of the main and interaction effects of two factors. Previous studies focused more on unbiased estimates of…

  6. The contour method: a new approach in experimental mechanics

    SciTech Connect

    Prime, Michael B

    2009-01-01

    The recently developed contour method can measure complex residual-stress maps in situations where other measurement methods cannot. This talk first describes the principle of the contour method. A part is cut in two using a precise and low-stress cutting technique such as electric discharge machining. The contour of the resulting new surface, which will not be flat if residual stresses are relaxed by the cutting, is then measured. Finally, a conceptually simple finite element analysis determines the original residual stresses from the measured contour. Next, this talk gives several examples of applications. The method is validated by comparing with neutron diffraction measurements in an indented steel disk and in a friction stir weld between dissimilar aluminum alloys. Several applications are shown that demonstrate the power of the contour method: large aluminum forgings, railroad rails, and welds. Finally, this talk discusses why the contour method is significant departure from conventional experimental mechanics. Other relaxation method, for example hole-drilling, can only measure a 1-D profile of residual stresses, and yet they require a complicated inverse calculation to determine the stresses from the strain data. The contour method gives a 2-D stress map over a full cross-section, yet a direct calculation is all that is needed to reduce the data. The reason for these advantages lies in a subtle but fundamental departure from conventional experimental mechanics. Applying new technology to old methods like will not give similar advances, but the new approach also introduces new errors.

  7. An Experimental Method for Stereolithic Mandible Fabrication and Image Preparation

    PubMed Central

    Russett, Shawn; Major, Paul; Carey, Jason; Toogood, Roger; Boulanger, Pierre

    2007-01-01

    Reproduction of anatomical structures by rapid prototyping has proven to be a valid adjunct for craniofacial surgery, providing alternative methods to produce prostheses and development of surgical guides. The aim of this study was to introduce a methodology to fabricate asymmetric human mandibles by rapid prototyping to be used in future studies for evaluating mandibular symmetries. Stereolithic models of human mandibles were produced with varying amounts of asymmetry in the condylar neck, ramus and body of the mandible by means of rapid prototyping. A method for production of the synthetic mandibles was defined. Model preparation, landmark description and development of the experimental model were described. A series of synthetic mandibles ranging in asymmetry were accurately produced from a scanned human mandible. A method for creating the asymmetries, fabricating, coating and landmarking the synthetic mandibles was formulated. A description for designing a reproducible experimental model for image acquisition was also outlined. Production of synthetic mandibles by stereolithic modeling is a viable method for creating skeletal experimental models with known amounts of asymmetry. PMID:19662121

  8. Nonlinear feedback method of robot control - A preliminary experimental study

    NASA Technical Reports Server (NTRS)

    Tarn, T. J.; Ganguly, S.; Li, Z.; Bejczy, A. K.

    1990-01-01

    The nonlinear feedback method of robot control has been experimentally implemented on two PUMA 560 robot arms. The feasibility of the proposed controller, which was shown viable through simulation results earlier, is stressed. The servomechanism operates in task space, and the nonlinear feedback takes care of the necessary transformations to compute the necessary joint currents. A discussion is presented of the implementation with details of the experiments performed. The performance of the controller is encouraging but was limited to 100-Hz sampling frequency and to derived velocity information at the time of the experimentation. The setup of the lab, the software aspects, results, and the control hardware architecture that has recently been implemented are discussed.

  9. Method of fission heat flux determination from experimental data

    DOEpatents

    Paxton, Frank A.

    1999-01-01

    A method is provided for determining the fission heat flux of a prime specimen inserted into a specimen of a test reactor. A pair of thermocouple test specimens are positioned at the same level in the holder and a determination is made of various experimental data including the temperature of the thermocouple test specimens, the temperature of bulk water channels located in the test holder, the gamma scan count ratios for the thermocouple test specimens and the prime specimen, and the thicknesses of the outer clads, the fuel fillers, and the backclad of the thermocouple test specimen. Using this experimental data, the absolute value of the fission heat flux for the thermocouple test specimens and prime specimen can be calculated.

  10. Nonlinear feedback method of robot control - A preliminary experimental study

    NASA Technical Reports Server (NTRS)

    Tarn, T. J.; Ganguly, S.; Li, Z.; Bejczy, A. K.

    1990-01-01

    The nonlinear feedback method of robot control has been experimentally implemented on two PUMA 560 robot arms. The feasibility of the proposed controller, which was shown viable through simulation results earlier, is stressed. The servomechanism operates in task space, and the nonlinear feedback takes care of the necessary transformations to compute the necessary joint currents. A discussion is presented of the implementation with details of the experiments performed. The performance of the controller is encouraging but was limited to 100-Hz sampling frequency and to derived velocity information at the time of the experimentation. The setup of the lab, the software aspects, results, and the control hardware architecture that has recently been implemented are discussed.

  11. An experimental design method leading to chemical Turing patterns.

    PubMed

    Horváth, Judit; Szalai, István; De Kepper, Patrick

    2009-05-08

    Chemical reaction-diffusion patterns often serve as prototypes for pattern formation in living systems, but only two isothermal single-phase reaction systems have produced sustained stationary reaction-diffusion patterns so far. We designed an experimental method to search for additional systems on the basis of three steps: (i) generate spatial bistability by operating autoactivated reactions in open spatial reactors; (ii) use an independent negative-feedback species to produce spatiotemporal oscillations; and (iii) induce a space-scale separation of the activatory and inhibitory processes with a low-mobility complexing agent. We successfully applied this method to a hydrogen-ion autoactivated reaction, the thiourea-iodate-sulfite (TuIS) reaction, and noticeably produced stationary hexagonal arrays of spots and parallel stripes of pH patterns attributed to a Turing bifurcation. This method could be extended to biochemical reactions.

  12. An experimental comparison of various methods of nearfield acoustic holography

    NASA Astrophysics Data System (ADS)

    Chelliah, Kanthasamy; Raman, Ganesh; Muehleisen, Ralph T.

    2017-09-01

    An experimental comparison of four different methods of nearfield acoustic holography (NAH) for planar acoustic sources is presented in this study. The four NAH methods considered in this study are based on: (1) spatial Fourier transform, (2) equivalent sources model, (3) boundary element methods and (4) statistically optimized NAH. Two dimensional measurements were obtained at distances ranging from one-half to sixteen microphone spacings away from a sound source and the NAH methods were used to reconstruct the sound field at the source surface. Reconstructed particle velocity and acoustic pressure fields presented in this study showed that the equivalent sources model based algorithm along with Tikhonov regularization provided the best localization of the sources. Reconstruction errors were found to be smaller for the equivalent sources model based algorithm and the statistically optimized NAH algorithm. The effects of hologram distance on the performance of various algorithms are discussed in detail. The study also compares the computational time required by each algorithm to calculate the reconstruction. Four different regularization parameter choice methods were compared. The L-curve method provided more accurate reconstructions than the generalized cross validation and the Morozov discrepancy principle at larger measurement distances. The performance of fixed parameter regularization was comparable to that of the L-curve method.

  13. An experimental comparison of various methods of nearfield acoustic holography

    DOE PAGES

    Chelliah, Kanthasamy; Raman, Ganesh; Muehleisen, Ralph T.

    2017-05-19

    An experimental comparison of four different methods of nearfield acoustic holography (NAH) is presented in this study for planar acoustic sources. The four NAH methods considered in this study are based on: (1) spatial Fourier transform, (2) equivalent sources model, (3) boundary element methods and (4) statistically optimized NAH. Two dimensional measurements were obtained at different distances in front of a tonal sound source and the NAH methods were used to reconstruct the sound field at the source surface. Reconstructed particle velocity and acoustic pressure fields presented in this study showed that the equivalent sources model based algorithm along withmore » Tikhonov regularization provided the best localization of the sources. Reconstruction errors were found to be smaller for the equivalent sources model based algorithm and the statistically optimized NAH algorithm. Effect of hologram distance on the performance of various algorithms is discussed in detail. The study also compares the computational time required by each algorithm to complete the comparison. Four different regularization parameter choice methods were compared. The L-curve method provided more accurate reconstructions than the generalized cross validation and the Morozov discrepancy principle. Finally, the performance of fixed parameter regularization was comparable to that of the L-curve method.« less

  14. Alternate Methods to Experimentally Investigate Shock Initiation Properties of Explosives

    NASA Astrophysics Data System (ADS)

    Svingala, Forrest; Lee, Richard; Sutherland, Gerrit; Samuels, Philip

    2015-06-01

    Reactive flow models are desired for many new explosives early in the formulation development stage. Traditionally, these models are parameterized by carefully-controlled 1-D shock experiments, including gas-gun testing with embedded gauges and wedge testing with explosive plane wave lenses (PWL). These experiments are easy to interpret, due to their 1-D nature, but are generally expensive to perform, and cannot be performed at all explosive test facilities. We investigate alternative methods to probe shock-initiation behavior of new explosives using widely-available pentolite gap test donors and simple time-of-arrival type diagnostics. These methods can be performed at a low cost at virtually any explosives testing facility, which allows experimental data to parameterize reactive flow models to be collected much earlier in the development of an explosive formulation. However, the fundamentally 2-D nature of these tests may increase the modeling burden in parameterizing these models, and reduce general applicability. Several variations of the so-called modified gap test were investigated and evaluated for suitability as an alternative to established 1-D gas gun and PWL techniques. At least partial agreement with 1-D test methods was observed for the explosives tested, and future work is planned to scope the applicability and limitations of these experimental techniques.

  15. Experimental physical methods and theories--then and now.

    PubMed

    Schulte, Jurgen

    2015-10-01

    A first evaluation of fundamental research into the physics and physiology of Ultra high dilutions (UHDs) was conducted by the author in 1994(1). In this paper we revisit methods and theories from back then and follow their paths through their evolution and contribution to new knowledge in UHD research since then. Physical methods and theories discusses in our anthology on UHD in 1994(1) form the basis for tracing ideas and findings along their path of further development and impact on new knowledge in UHD. Experimental approaches to probe physical changes in homeopathic preparations have become more sophisticated over past two decades, so did the desire to report results to a scientific standard that is on par with those in specialist literature. The same cannot be said about underlying supporting theoretical models and simulations. Grant challenges in science often take a more targeted and more concerted approach to formulate a research question and then look for answers. A concerted effort to focus on one hypothesized physical aspect of a well-defined homeopathic preparation may help aligning experimental methods with theoretical models and, in doing so, help to gain a deeper understanding of the whole body of insights and data produced. Copyright © 2015 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

  16. An experimental method for studying two-dimensional percolation

    NASA Astrophysics Data System (ADS)

    Schwartz, Gustavo Ariel; Ludueña, Silvio J.

    2004-03-01

    A simple experimental technique for analyzing a broad range of two-dimensional percolation problems is presented. The method is based on a combination of the use of a CAD program capable of dealing with a variety of site-bond combinations and an electrical measurement of conductance. The latter is achieved by printing the computer generated pattern using conducting ink. The metal-insulator transition is measured on the print out of the lattice, and the conductivity critical exponent and the percolation threshold are calculated from these measurements.

  17. The Assessment of Experimental Methods of Serial Number Restoration

    NASA Astrophysics Data System (ADS)

    Argo, Mackenzie

    Serial number restoration is a common and successful process of revealing obliterated serial numbers on firearms. In a crime laboratory setting, obliterated serial numbers are commonly processed in order to tie a person to a crime scene or provide an investigative lead for officers. Currently serial numbers are restored using a chemical etchant method that can eat away at the metal on the firearm even after the examination is complete. It can also take several hours to complete and only provide an examiner with a partial number. There are other nondestructive options however little to no literature is available. The purpose of this study is to discover new methods for nondestructive serial number restoration and to compare them to the traditional chemical method used. Metal bars of premeasured obliteration depths and different compositions were examined using three proposed experimental methods: near infrared imaging, cold frost, and scanning acoustic microscopy. Results did not indicate significant difference in the median number of visible digits recovered for each of the three proposed methods compared to the traditional chemical method. There were significant results in the median number of composition utilized and depth of obliteration. This indicates that different firearm compositions and depth of obliteration has an effect on serial number restoration.

  18. Optimal experimental design with the sigma point method.

    PubMed

    Schenkendorf, R; Kremling, A; Mangold, M

    2009-01-01

    Using mathematical models for a quantitative description of dynamical systems requires the identification of uncertain parameters by minimising the difference between simulation and measurement. Owing to the measurement noise also, the estimated parameters possess an uncertainty expressed by their variances. To obtain highly predictive models, very precise parameters are needed. The optimal experimental design (OED) as a numerical optimisation method is used to reduce the parameter uncertainty by minimising the parameter variances iteratively. A frequently applied method to define a cost function for OED is based on the inverse of the Fisher information matrix. The application of this traditional method has at least two shortcomings for models that are nonlinear in their parameters: (i) it gives only a lower bound of the parameter variances and (ii) the bias of the estimator is neglected. Here, the authors show that by applying the sigma point (SP) method a better approximation of characteristic values of the parameter statistics can be obtained, which has a direct benefit on OED. An additional advantage of the SP method is that it can also be used to investigate the influence of the parameter uncertainties on the simulation results. The SP method is demonstrated for the example of a widely used biological model.

  19. Experimental evaluation of the certification-trail method

    NASA Technical Reports Server (NTRS)

    Sullivan, Gregory F.; Wilson, Dwight S.; Masson, Gerald M.; Itoh, Mamoru; Smith, Warren W.; Kay, Jonathan S.

    1993-01-01

    Certification trails are a recently introduced and promising approach to fault-detection and fault-tolerance. A comprehensive attempt to assess experimentally the performance and overall value of the method is reported. The method is applied to algorithms for the following problems: huffman tree, shortest path, minimum spanning tree, sorting, and convex hull. Our results reveal many cases in which an approach using certification-trails allows for significantly faster overall program execution time than a basic time redundancy-approach. Algorithms for the answer-validation problem for abstract data types were also examined. This kind of problem provides a basis for applying the certification-trail method to wide classes of algorithms. Answer-validation solutions for two types of priority queues were implemented and analyzed. In both cases, the algorithm which performs answer-validation is substantially faster than the original algorithm for computing the answer. Next, a probabilistic model and analysis which enables comparison between the certification-trail method and the time-redundancy approach were presented. The analysis reveals some substantial and sometimes surprising advantages for ther certification-trail method. Finally, the work our group performed on the design and implementation of fault injection testbeds for experimental analysis of the certification trail technique is discussed. This work employs two distinct methodologies, software fault injection (modification of instruction, data, and stack segments of programs on a Sun Sparcstation ELC and on an IBM 386 PC) and hardware fault injection (control, address, and data lines of a Motorola MC68000-based target system pulsed at logical zero/one values). Our results indicate the viability of the certification trail technique. It is also believed that the tools developed provide a solid base for additional exploration.

  20. Experimental validation of boundary element methods for noise prediction

    NASA Technical Reports Server (NTRS)

    Seybert, A. F.; Oswald, Fred B.

    1992-01-01

    Experimental validation of methods to predict radiated noise is presented. A combined finite element and boundary element model was used to predict the vibration and noise of a rectangular box excited by a mechanical shaker. The predicted noise was compared to sound power measured by the acoustic intensity method. Inaccuracies in the finite element model shifted the resonance frequencies by about 5 percent. The predicted and measured sound power levels agree within about 2.5 dB. In a second experiment, measured vibration data was used with a boundary element model to predict noise radiation from the top of an operating gearbox. The predicted and measured sound power for the gearbox agree within about 3 dB.

  1. Integrating Informative Priors from Experimental Research with Bayesian Methods

    PubMed Central

    Hamra, Ghassan; Richardson, David; MacLehose, Richard; Wing, Steve

    2013-01-01

    Informative priors can be a useful tool for epidemiologists to handle problems of sparse data in regression modeling. It is sometimes the case that an investigator is studying a population exposed to two agents, X and Y, where Y is the agent of primary interest. Previous research may suggest that the exposures have different effects on the health outcome of interest, one being more harmful than the other. Such information may be derived from epidemiologic analyses; however, in the case where such evidence is unavailable, knowledge can be drawn from toxicologic studies or other experimental research. Unfortunately, using toxicologic findings to develop informative priors in epidemiologic analyses requires strong assumptions, with no established method for its utilization. We present a method to help bridge the gap between animal and cellular studies and epidemiologic research by specification of an order-constrained prior. We illustrate this approach using an example from radiation epidemiology. PMID:23222512

  2. Theoretical and experimental physical methods of neutron-capture therapy

    NASA Astrophysics Data System (ADS)

    Borisov, G. I.

    2011-09-01

    This review is based to a substantial degree on our priority developments and research at the IR-8 reactor of the Russian Research Centre Kurchatov Institute. New theoretical and experimental methods of neutron-capture therapy are developed and applied in practice; these are: A general analytical and semi-empiric theory of neutron-capture therapy (NCT) based on classical neutron physics and its main sections (elementary theories of moderation, diffuse, reflection, and absorption of neutrons) rather than on methods of mathematical simulation. The theory is, first of all, intended for practical application by physicists, engineers, biologists, and physicians. This theory can be mastered by anyone with a higher education of almost any kind and minimal experience in operating a personal computer.

  3. Applying analytical and experimental methods to characterize engineered components

    NASA Astrophysics Data System (ADS)

    Munn, Brian S.

    A variety of analytical and experimental methods were employed to characterize two very different types of engineered components. The engineered components of interest were monolithic silicon carbide tiles and M12 x 1.75 Class 9.8 steel fasteners. A new application applying the hole drilling technique was developed on monolithic silicon-carbide tiles of varying thicknesses. This work was driven by a need to first develop a reliable method to measure residual stresses and, then, to validate the methodology through characterizing residual stresses on the tiles of interest. The residual stresses measured in all tiles were tensile in nature. The highest residual stresses were measured at the surface, and decreased exponentially. There was also a trend for the residual tensile stresses to decrease with increasing specimen thickness. Thermal-mechanical interactions were successfully analyzed via a one-way, coupled FEA modeled approach. The key input for a successful FEA analysis was an appropriate heat transfer rate. By varying the heat transfer rate in the FEA model and, then, comparing stress output to experimental residual stress values, provided a favorable numerical solution in determining a heat transfer rate. Fatigue behavior of a M12 x 1.75 Class 9.8 steel test fastener was extensively studied through the use of a variety of experimental and analytical techniques. Of particular interest, was the underlying interaction between notch plasticity and overall fatigue behavior. A very large data set of fastener fatigue behavior was generated with respect to mean stress. A series of endurance limit curves were established for different mean stress values ranging from minimal to the yield strength of the steel fastener (0 ≤ sigmam ≤ sigmay). This wide range in mean stress values created a change in notch tip plasticity which caused a local diminishing of the mean stress increasing expected fatigue life. The change in notch plasticity was identified by residual stress

  4. Experimental Methods for Trapping Ions Using Microfabricated Surface Ion Traps.

    PubMed

    Hong, Seokjun; Lee, Minjae; Kwon, Yeong-Dae; Cho, Dong-Il Dan; Kim, Taehyun

    2017-08-17

    Ions trapped in a quadrupole Paul trap have been considered one of the strong physical candidates to implement quantum information processing. This is due to their long coherence time and their capability to manipulate and detect individual quantum bits (qubits). In more recent years, microfabricated surface ion traps have received more attention for large-scale integrated qubit platforms. This paper presents a microfabrication methodology for ion traps using micro-electro-mechanical system (MEMS) technology, including the fabrication method for a 14 µm-thick dielectric layer and metal overhang structures atop the dielectric layer. In addition, an experimental procedure for trapping ytterbium (Yb) ions of isotope 174 ((174)Yb(+)) using 369.5 nm, 399 nm, and 935 nm diode lasers is described. These methodologies and procedures involve many scientific and engineering disciplines, and this paper first presents the detailed experimental procedures. The methods discussed in this paper can easily be extended to the trapping of Yb ions of isotope 171 ((171)Yb(+)) and to the manipulation of qubits.

  5. Detection of interaction articles and experimental methods in biomedical literature.

    PubMed

    Schneider, Gerold; Clematide, Simon; Rinaldi, Fabio

    2011-10-03

    This article describes the approaches taken by the OntoGene group at the University of Zurich in dealing with two tasks of the BioCreative III competition: classification of articles which contain curatable protein-protein interactions (PPI-ACT) and extraction of experimental methods (PPI-IMT). Two main achievements are described in this paper: (a) a system for document classification which crucially relies on the results of an advanced pipeline of natural language processing tools; (b) a system which is capable of detecting all experimental methods mentioned in scientific literature, and listing them with a competitive ranking (AUC iP/R > 0.5). The results of the BioCreative III shared evaluation clearly demonstrate that significant progress has been achieved in the domain of biomedical text mining in the past few years. Our own contribution, together with the results of other participants, provides evidence that natural language processing techniques have become by now an integral part of advanced text mining approaches.

  6. Method to deterministically study photonic nanostructures in different experimental instruments.

    PubMed

    Husken, B H; Woldering, L A; Blum, C; Vos, W L

    2009-01-01

    We describe an experimental method to recover a single, deterministically fabricated nanostructure in various experimental instruments without the use of artificially fabricated markers, with the aim to study photonic structures. Therefore, a detailed map of the spatial surroundings of the nanostructure is made during the fabrication of the structure. These maps are made using a series of micrographs with successively decreasing magnifications. The graphs reveal intrinsic and characteristic geometric features that can subsequently be used in different setups to act as markers. As an illustration, we probe surface cavities with radii of 65 nm on a silica opal photonic crystal with various setups: a focused ion beam workstation; a scanning electron microscope (SEM); a wide field optical microscope and a confocal microscope. We use cross-correlation techniques to recover a small area imaged with the SEM in a large area photographed with the optical microscope, which provides a possible avenue to automatic searching. We show how both structural and optical reflectivity data can be obtained from one and the same nanostructure. Since our approach does not use artificial grids or markers, it is of particular interest for samples whose structure is not known a priori, like samples created solely by self-assembly. In addition, our method is not restricted to conducting samples.

  7. Experimental Investigation of Low-Cost Cooling Methods

    NASA Astrophysics Data System (ADS)

    Mazumder, M.

    2016-12-01

    An estimated 1.2 billion people in the world do not have access to constant supply of electricity. The goal of this research project is experimental investigation of cooling mechanisms for low cost refrigeration without constant supply of electricity. Experimental investigations were performed in 3 separate phases: 1) We first tested common literature method of evaporative cooling mechanism of the pot-in-pot refrigeration system, developed by Mohammed Bah Abba. Experiments showed that the cooling power of the original system is theoretically limited to the wet bulb temperature, and in an environment with 70º F ambient temperature, cooling never exceeded 7-8 degrees. 2) Next, we conducted an experimental study of heat transfer processes through the use of a simple glass model. The results of the glass model showed that thorough insulation and ice were crucial to improving cooling. Hence, we incorporated the use of ice and insulating fabrics in the system. This improved the existing methods by 2x but required much maintenance, with constant watering of sand and replacement of ice packs. Our next set of experiments with a 60-liter clay pot filled with water and 3.5-8 kg ice blocks showed that more than 20 degree cooling can be achieved with moderate amount of ice and insulation for over a few days. 3) Next, we used HOBO temperature sensors, a 60-liter pot, water, ice, and several layers of insulation, and proved that with proper insulation and even just one 8-kg block of ice, the system yielded a greater cooling for over two weeks, with temperatures ranging from 61.8 and 68.9 ºF even when the ambient temperature was as high as 109º F. The temperature inside the system stayed relatively constant, with changes only corresponding to day and night. Additional experimentation showed that initial cooling was proportional to the amount of ice put in the system, and thus with double the ice, temperatures could reach as low as 34.9 ºF. This research proves that the

  8. Natural experimentation is a challenging method for identifying headache triggers

    PubMed Central

    Houle, Timothy T.; Turner, Dana P.

    2015-01-01

    Objective In this study we set out to determine whether individual headache sufferers can learn about the potency of their headache triggers (causes) using only natural experimentation. Background Headache patients naturally use the covariation of the presence-absence of triggers with headache attacks to assess the potency of triggers. The validity of this natural experimentation has never been investigated. A companion study has proposed three assumptions that are important for assigning causal status to triggers. This manuscript examines one of these assumptions, constancy in trigger presentation, using real-world conditions. Methods The similarity of day-to-day weather conditions over four years, as well as the similarity of ovarian hormones and perceived stress over a median of 89 days in nine regularly cycling headache sufferers were examined using several available time-series. An arbitrary threshold of 90% similarity using Gower's index identified similar days for comparison. Results The day-to-day variability in just these three headache triggers is substantial enough that finding two naturally similar days for which to contrast the effect of a fourth trigger (e.g., drinking wine versus not drinking wine) will only infrequently occur. Fluctuations in weather patterns resulted in a median of 2.3 days each year that were similar (range: 0 to 27.4). Considering fluctuations in stress patterns and ovarian hormones, only 1.5 days/month (95%CI: 1.2 to 2.9) and 2.0 days/month (95%CI: 1.9 to 2.2), respectively, met our threshold for similarity.. Conclusion Although assessing the personal causes of headache is an age-old endeavor, the great many candidate triggers exhibit variability that may prevent sound conclusions without assistance from formal experimentation or statistical balancing. PMID:23534852

  9. Experimental evaluation of chromatic dispersion estimation method using polynomial fitting

    NASA Astrophysics Data System (ADS)

    Jiang, Xin; Wang, Junyi; Pan, Zhongqi

    2014-11-01

    We experimentally validate a non-data-aided, modulation-format independent chromatic dispersion (CD) estimation method based on polynomial fitting algorithm in single-carrier coherent optical system with a 40 Gb/s polarization-division-multiplexed quadrature-phase-shift-keying (PDM-QPSK) system. The non-data-aided CD estimation for arbitrary modulation formats is achieved by measuring the differential phase between frequency f±fs/2 (fs is the symbol rate) in digital coherent receivers. The estimation range for a 40 Gb/s PDM-QPSK signal can be up to 20,000 ps/nm with a measurement accuracy of ±200 ps/nm. The maximum CD measurement is 25,000 ps/nm with a measurement error of 2%.

  10. Experimental methods of molecular matter-wave optics.

    PubMed

    Juffmann, Thomas; Ulbricht, Hendrik; Arndt, Markus

    2013-08-01

    We describe the state of the art in preparing, manipulating and detecting coherent molecular matter. We focus on experimental methods for handling the quantum motion of compound systems from diatomic molecules to clusters or biomolecules.Molecular quantum optics offers many challenges and innovative prospects: already the combination of two atoms into one molecule takes several well-established methods from atomic physics, such as for instance laser cooling, to their limits. The enormous internal complexity that arises when hundreds or thousands of atoms are bound in a single organic molecule, cluster or nanocrystal provides a richness that can only be tackled by combining methods from atomic physics, chemistry, cluster physics, nanotechnology and the life sciences.We review various molecular beam sources and their suitability for matter-wave experiments. We discuss numerous molecular detection schemes and give an overview over diffraction and interference experiments that have already been performed with molecules or clusters.Applications of de Broglie studies with composite systems range from fundamental tests of physics up to quantum-enhanced metrology in physical chemistry, biophysics and the surface sciences.Nanoparticle quantum optics is a growing field, which will intrigue researchers still for many years to come. This review can, therefore, only be a snapshot of a very dynamical process.

  11. Experimental methods of molecular matter-wave optics

    NASA Astrophysics Data System (ADS)

    Juffmann, Thomas; Ulbricht, Hendrik; Arndt, Markus

    2013-08-01

    We describe the state of the art in preparing, manipulating and detecting coherent molecular matter. We focus on experimental methods for handling the quantum motion of compound systems from diatomic molecules to clusters or biomolecules. Molecular quantum optics offers many challenges and innovative prospects: already the combination of two atoms into one molecule takes several well-established methods from atomic physics, such as for instance laser cooling, to their limits. The enormous internal complexity that arises when hundreds or thousands of atoms are bound in a single organic molecule, cluster or nanocrystal provides a richness that can only be tackled by combining methods from atomic physics, chemistry, cluster physics, nanotechnology and the life sciences. We review various molecular beam sources and their suitability for matter-wave experiments. We discuss numerous molecular detection schemes and give an overview over diffraction and interference experiments that have already been performed with molecules or clusters. Applications of de Broglie studies with composite systems range from fundamental tests of physics up to quantum-enhanced metrology in physical chemistry, biophysics and the surface sciences. Nanoparticle quantum optics is a growing field, which will intrigue researchers still for many years to come. This review can, therefore, only be a snapshot of a very dynamical process.

  12. Modeling methods for merging computational and experimental aerodynamic pressure data

    NASA Astrophysics Data System (ADS)

    Haderlie, Jacob C.

    This research describes a process to model surface pressure data sets as a function of wing geometry from computational and wind tunnel sources and then merge them into a single predicted value. The described merging process will enable engineers to integrate these data sets with the goal of utilizing the advantages of each data source while overcoming the limitations of both; this provides a single, combined data set to support analysis and design. The main challenge with this process is accurately representing each data source everywhere on the wing. Additionally, this effort demonstrates methods to model wind tunnel pressure data as a function of angle of attack as an initial step towards a merging process that uses both location on the wing and flow conditions (e.g., angle of attack, flow velocity or Reynold's number) as independent variables. This surrogate model of pressure as a function of angle of attack can be useful for engineers that need to predict the location of zero-order discontinuities, e.g., flow separation or normal shocks. Because, to the author's best knowledge, there is no published, well-established merging method for aerodynamic pressure data (here, the coefficient of pressure Cp), this work identifies promising modeling and merging methods, and then makes a critical comparison of these methods. Surrogate models represent the pressure data for both data sets. Cubic B-spline surrogate models represent the computational simulation results. Machine learning and multi-fidelity surrogate models represent the experimental data. This research compares three surrogates for the experimental data (sequential--a.k.a. online--Gaussian processes, batch Gaussian processes, and multi-fidelity additive corrector) on the merits of accuracy and computational cost. The Gaussian process (GP) methods employ cubic B-spline CFD surrogates as a model basis function to build a surrogate model of the WT data, and this usage of the CFD surrogate in building the WT

  13. Optical bandgap of semiconductor nanostructures: Methods for experimental data analysis

    NASA Astrophysics Data System (ADS)

    Raciti, R.; Bahariqushchi, R.; Summonte, C.; Aydinli, A.; Terrasi, A.; Mirabella, S.

    2017-06-01

    Determination of the optical bandgap (Eg) in semiconductor nanostructures is a key issue in understanding the extent of quantum confinement effects (QCE) on electronic properties and it usually involves some analytical approximation in experimental data reduction and modeling of the light absorption processes. Here, we compare some of the analytical procedures frequently used to evaluate the optical bandgap from reflectance (R) and transmittance (T) spectra. Ge quantum wells and quantum dots embedded in SiO2 were produced by plasma enhanced chemical vapor deposition, and light absorption was characterized by UV-Vis/NIR spectrophotometry. R&T elaboration to extract the absorption spectra was conducted by two approximated methods (single or double pass approximation, single pass analysis, and double pass analysis, respectively) followed by Eg evaluation through linear fit of Tauc or Cody plots. Direct fitting of R&T spectra through a Tauc-Lorentz oscillator model is used as comparison. Methods and data are discussed also in terms of the light absorption process in the presence of QCE. The reported data show that, despite the approximation, the DPA approach joined with Tauc plot gives reliable results, with clear advantages in terms of computational efforts and understanding of QCE.

  14. New experimental method for investigation of the nucleon polarizabilities

    NASA Astrophysics Data System (ADS)

    Yevetska, O.; Watzlawik, S.; Ahrens, J.; Alkhazov, G. D.; Chizhov, V. P.; Maev, E. M.; von Neumann-Cosel, P.; Orischin, E. M.; Petrov, G. E.; Porté, J.-M.; Richter, A.; Sarantsev, V. V.; Schrieder, G.; Smirenin, Yu. V.

    2010-06-01

    At the continuous wave (cw) Superconducting Darmstadt Electron Linear Accelerator S-DALINAC, a new method has been developed for the determination of the electric ( α¯) and magnetic ( β¯) polarizabilities of the proton and the deuteron. For that purpose the energy and angular dependence of the differential cross-section for elastic γp and γd scattering of bremsstrahlung photons in the energy range between 20 and 100 MeV is measured by detecting the recoiling proton (deuteron) in coincidence with the scattered bremsstrahlung photon. α¯ and β¯ are then found by means of a best fit to a theoretical description of the scattering cross-section with these quantities as open parameters. The experimental setup consists of a bremsstrahlung photon facility, two specially designed high pressure hydrogen (deuterium) ionization chambers which serve as targets and detectors of the recoil proton (deuteron), NaI gamma spectrometers and several additional detectors for beam diagnostics and normalization. The whole setup was tested using bremsstrahlung photon beams with endpoint energies of 60 and 79.3 MeV. The results of the test experiments show that future high-statistics measurements are feasible.

  15. Theoretical and experimental investigation of multispectral photoacoustic osteoporosis detection method

    NASA Astrophysics Data System (ADS)

    Steinberg, Idan; Hershkovich, Hadas Sara; Gannot, Israel; Eyal, Avishay

    2014-03-01

    Osteoporosis is a widespread disorder, which has a catastrophic impact on patients lives and overwhelming related to healthcare costs. Recently, we proposed a multispectral photoacoustic technique for early detection of osteoporosis. Such technique has great advantages over pure ultrasonic or optical methods as it allows the deduction of both bone functionality from the bone absorption spectrum and bone resistance to fracture from the characteristics of the ultrasound propagation. We demonstrated the propagation of multiple acoustic modes in animal bones in-vitro. To further investigate the effects of multiple wavelength excitations and of induced osteoporosis on the PA signal a multispectral photoacoustic system is presented. The experimental investigation is based on measuring the interference of multiple acoustic modes. The performance of the system is evaluated and a simple two mode theoretical model is fitted to the measured phase signals. The results show that such PA technique is accurate and repeatable. Then a multiple wavelength excitation is tested. It is shown that the PA response due to different excitation wavelengths revels that absorption by the different bone constitutes has a profound effect on the mode generation. The PA response is measured in single wavelength before and after induced osteoporosis. Results show that induced osteoporosis alters the measured amplitude and phase in a consistent manner which allows the detection of the onset of osteoporosis. These results suggest that a complete characterization of the bone over a region of both acoustic and optical frequencies might be used as a powerful tool for in-vivo bone evaluation.

  16. A cross-spectrum weighting algorithm for speech enhancement and array processing: combining phase-shift information and stationary signal properties.

    PubMed

    Schwetz, Ingo; Gruhler, Gerhard; Obermayer, Klaus

    2006-02-01

    In this paper, a gain function for noise cancellation with a two-channel microphone array is presented. This gain function combines ideas from one- and multichannel algorithms. It is developed using a minimum mean square error estimator for the amplitude of the speech signal from the cross spectrum between two microphone signals. To consider speech pauses and the absence of spectral components of the speech, an extension of this gain function is presented. The performance of the overall gain function is shown in terms of the cancellation of (diffuse) driving noise as well as the cancellation of an interfering speech signal, both recorded in a car.

  17. Can We Study Intelligence Using the Experimental Method?

    ERIC Educational Resources Information Center

    Eysenck, Hans J.

    1995-01-01

    It is argued that the study of one important aspect of intelligence, creativity, can be furthered by the introduction of causal theories and their experimental study. Purely correlational investigations are a useful beginning, but psychology can only acquire true scientific stature by combining correlational and experimental approaches. (SLD)

  18. Can We Study Intelligence Using the Experimental Method?

    ERIC Educational Resources Information Center

    Eysenck, Hans J.

    1995-01-01

    It is argued that the study of one important aspect of intelligence, creativity, can be furthered by the introduction of causal theories and their experimental study. Purely correlational investigations are a useful beginning, but psychology can only acquire true scientific stature by combining correlational and experimental approaches. (SLD)

  19. Investigation of orifice aeroacoustics by means of multi-port methods

    NASA Astrophysics Data System (ADS)

    Sack, Stefan; Åbom, Mats

    2017-10-01

    Comprehensive methods to cascade active multi-ports, e.g., for acoustic network prediction, have until now only been available for plane waves. This paper presents procedures to combine multi-ports with an arbitrary number of considered duct modes. A multi-port method is used to extract complex mode amplitudes from experimental data of single and tandem in-duct orifice plates for Helmholtz numbers up to around 4 and, hence, beyond the cut-on of several higher order modes. The theory of connecting single multi-ports to linear cascades is derived for the passive properties (the scattering of the system) and the active properties (the source cross-spectrum matrix of the system). One scope of this paper is to investigate the influence of the hydrodynamic near field on the accuracy of both the passive and the active predictions in multi-port cascades. The scattering and the source cross-spectrum matrix of tandem orifice configurations is measured for three cases, namely, with a distance between the plates of 10 duct diameter, for which the downstream orifice is outside the jet of the upstream orifice, 4 duct diameter, and 2 duct diameter (both inside the jet). The results are compared with predictions from single orifice measurements. It is shown that the scattering is only sensitive to disturbed inflow in certain frequency ranges where coupling between the flow and sound field exists, whereas the source cross-spectrum matrix is very sensitive to disturbed inflow for all frequencies. An important part of the analysis is based on an eigenvalue analysis of the scattering matrix and the source cross-spectrum matrix to evaluate the potential of sound amplification and dominant source mechanisms.

  20. The Cutting Methods Demonstration Study at Fraser Experimental Forest

    Treesearch

    Wayne D. Shepperd; Lance A. Asherin; Stephen A. Mata; Douglas L. McClain

    2004-01-01

    Efficiency of harvest, overstory regrowth, and regeneration establishment are compared among 12 even- and uneven-aged regeneration cuttings installed in 1984 in subalpine Engelmann spruce and lodgepole pine forests on the Fraser Experimental Forest in central Colorado. Individual tree selection and overstory removal prescriptions were much less efficient to log than...

  1. Assessing Methods for Generalizing Experimental Impact Estimates to Target Populations

    ERIC Educational Resources Information Center

    Kern, Holger L.; Stuart, Elizabeth A.; Hill, Jennifer; Green, Donald P.

    2016-01-01

    Randomized experiments are considered the gold standard for causal inference because they can provide unbiased estimates of treatment effects for the experimental participants. However, researchers and policymakers are often interested in using a specific experiment to inform decisions about other target populations. In education research,…

  2. Using Experimental Methods to Investigate Discriminatory Tendencies: A Lesson Report

    ERIC Educational Resources Information Center

    Chen, Yu-Wen; Masch, Lena; Finze, Kristin

    2014-01-01

    Using dictator games in experimental analysis, this lesson report demonstrates the process and results of a postgraduate class project in which university students were instructed to scientifically investigate and explore one of German society's most hotly-contested issues: the level of discriminatory tendencies of non-Muslims towards Muslims. The…

  3. Leveraging the Experimental Method to Inform Solar Cell Design

    ERIC Educational Resources Information Center

    Rose, Mary Annette; Ribblett, Jason W.; Hershberger, Heather Nicole

    2010-01-01

    In this article, the underlying logic of experimentation is exemplified within the context of a photoelectrical experiment for students taking a high school engineering, technology, or chemistry class. Students assume the role of photochemists as they plan, fabricate, and experiment with a solar cell made of copper and an aqueous solution of…

  4. Teaching Experimental Methods while Bringing Smiles to your Students' Faces.

    ERIC Educational Resources Information Center

    Grahe, Jon E.; Hinsz, Verlin B.; Williams, Kipling D.

    2000-01-01

    Illustrates a field experiment in which students studied whether people (1) respond to smiles with smiles and (2) fail to reciprocate frowns. Explains that the project facilitates understanding of methodological issues, such as random assignment, manipulation strength, and experimenter bias. Discusses the procedure and results from the project and…

  5. Leveraging the Experimental Method to Inform Solar Cell Design

    ERIC Educational Resources Information Center

    Rose, Mary Annette; Ribblett, Jason W.; Hershberger, Heather Nicole

    2010-01-01

    In this article, the underlying logic of experimentation is exemplified within the context of a photoelectrical experiment for students taking a high school engineering, technology, or chemistry class. Students assume the role of photochemists as they plan, fabricate, and experiment with a solar cell made of copper and an aqueous solution of…

  6. Assessing Methods for Generalizing Experimental Impact Estimates to Target Populations

    ERIC Educational Resources Information Center

    Kern, Holger L.; Stuart, Elizabeth A.; Hill, Jennifer; Green, Donald P.

    2016-01-01

    Randomized experiments are considered the gold standard for causal inference because they can provide unbiased estimates of treatment effects for the experimental participants. However, researchers and policymakers are often interested in using a specific experiment to inform decisions about other target populations. In education research,…

  7. Experimental methods of determining thermal properties of granite

    USDA-ARS?s Scientific Manuscript database

    Determination of thermal properties of granite using the block method is discussed and compared with other methods. Problems that limit the accuracy of contact method in determining thermal properties of porous media are evaluated. Thermal properties of granite is determined in the laboratory with a...

  8. Collection methods of trematode eggs using experimental animal models.

    PubMed

    Tsubokawa, Daigo; Sugiyama, Hiromu; Mikami, Fusako; Shibata, Katsumasa; Shibahara, Toshiyuki; Fukuda, Koichi; Takamiya, Shinzaburo; Yamasaki, Hiroshi; Nakamura, Takeshi; Tsuji, Naotoshi

    2016-10-01

    Although observing the eggs of human parasitic helminth is essential for medical education in parasitology, opportunities for collection of the eggs are limited. Collection of the eggs using experimental animal models is needed for a sustainable supply. The metacercariae of three trematode species, Paragonimus westermani, Clonorchis sinensis and Metagonimus yokogawai, were collected from the second intermediate hosts: freshwater crabs and fishes, which were obtained using online shopping in Japan, and inoculated to experimental animal rat and dog. Consequently, eggs of the three trematode species were obtained abundantly from the feces of the animals. The eggs are being used for student training in several Japanese universities. In this article, we introduce the collection procedures for trematode eggs.

  9. Finite element method - A companion in experimental mechanics

    NASA Technical Reports Server (NTRS)

    Kobayashi, A. S.

    1984-01-01

    The hybrid experimental-numerical procedure for structural analysis is described by its applications in fracture mechanics. The procedure was first verified by the excellent agreements between the dynamic stress intensity factors obtained directly by dynamic photoelasticity and those generated by the hybrid procedure where a dynamic finite element code was executed in its generation mode. The hybrid procedure was then used to determine the dynamic fracture toughness of reaction bonded silicon nitride.

  10. Finite element method - A companion in experimental mechanics

    NASA Technical Reports Server (NTRS)

    Kobayashi, A. S.

    1984-01-01

    The hybrid experimental-numerical procedure for structural analysis is described by its applications in fracture mechanics. The procedure was first verified by the excellent agreements between the dynamic stress intensity factors obtained directly by dynamic photoelasticity and those generated by the hybrid procedure where a dynamic finite element code was executed in its generation mode. The hybrid procedure was then used to determine the dynamic fracture toughness of reaction bonded silicon nitride.

  11. Method for experimental determination of flutter speed by parameter identification

    NASA Technical Reports Server (NTRS)

    Nissim, E.; Gilyard, Glenn B.

    1989-01-01

    A method for flight flutter testing is proposed which enables one to determine the flutter dynamic pressure from flights flown far below the flutter dynamic pressure. The method is based on the identification of the coefficients of the equations of motion at low dynamic pressures, followed by the solution of these equations to compute the flutter dynamic pressure. The initial results of simulated data reported in the present work indicate that the method can accurately predict the flutter dynamic pressure, as described. If no insurmountable difficulties arise in the implementation of this method, it may significantly improve the procedures for flight flutter testing.

  12. Experimental Implementation of a Nonlinear Control Method for Magnetostrictive Transducers

    DTIC Science & Technology

    2006-01-01

    we use classical PI control to compute δu; that is, we take δu(t) = −KP e(t)−KI ∫ t 0 e(s)ds. (25) The final control input is then u(t) = u∗(t) + δu...complete comparison between the two designs at multiple frequencies are reported, that with the 10 kHz sample frequency, PI control is viable at...Tracking authority provided by PI control at 1000 Hz. V. CONCLUDING REMARKS In this paper, we report initial experimental results demon- strating the

  13. Experimental verification of a recursive method to calculate evapotranspiration

    USDA-ARS?s Scientific Manuscript database

    Recently, a recursive combination method (RCM) to calculate potential and crop evapotranspiration (ET) was given by Lascano and Van Bavel (Agron. J. 2007, 99:585–590). The RCM differs from the Penman-Monteith (PM) method, the main difference being that the assumptions made regarding the temperature ...

  14. Experimental Methods in Reduced-gravity Soldering Research

    NASA Technical Reports Server (NTRS)

    Pettegrew, Richard D.; Struk, Peter M.; Watson, John K.; Haylett, Daniel R.

    2002-01-01

    The National Center for Microgravity Research, NASA Glenn Research Center, and NASA Johnson Space Center are conducting an experimental program to explore the influence of reduced gravity environments on the soldering process. An improved understanding of the effects of the acceleration environment is important to application of soldering during current and future human space missions. Solder joint characteristics that are being considered include solder fillet geometry, porosity, and microstructural features. Both through-hole and surface mounted devices are being investigated. This paper focuses on the experimental methodology employed in this project and the results of macroscopic sample examination. The specific soldering process, sample configurations, materials, and equipment were selected to be consistent with those currently on-orbit. Other apparatus was incorporated to meet requirements imposed by operation onboard NASA's KC-135 research aircraft and instrumentation was provided to monitor both the atmospheric and acceleration environments. The contingent of test operators was selected to include both highly skilled technicians and less skilled individuals to provide a population cross-section that would be representative of the skill mix that might be encountered in space mission crews.

  15. Practical application of stereological methods in experimental kidney animal models.

    PubMed

    Fernández García, María Teresa; Núñez Martínez, Paula; García de la Fuente, Vanessa; Sánchez Pitiot, Marta; Muñiz Salgueiro, María Del Carmen; Perillán Méndez, Carmen; Argüelles Luis, Juan; Astudillo González, Aurora

    The kidneys are vital organs responsible for excretion, fluid and electrolyte balance and hormone production. The nephrons are the kidney's functional and structural units. The number, size and distribution of the nephron components contain relevant information on renal function. Stereology is a branch of morphometry that applies mathematical principles to obtain three-dimensional information from serial, parallel and equidistant two-dimensional microscopic sections. Because of the complexity of stereological studies and the lack of scientific literature on the subject, the aim of this paper is to clearly explain, through animal models, the basic concepts of stereology and how to calculate the main kidney stereological parameters that can be applied in future experimental studies. Copyright © 2016 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.

  16. DETECTORS AND EXPERIMENTAL METHODS: BESIII track fitting algorithm

    NASA Astrophysics Data System (ADS)

    Wang, Ji-Ke; Mao, Ze-Pu; Bian, Jian-Ming; Cao, Guo-Fu; Cao, Xue-Xiang; Chen, Shen-Jian; Deng, Zi-Yan; Fu, Cheng-Dong; Gao, Yuan-Ning; He, Kang-Lin; He, Miao; Hua, Chun-Fei; Huang, Bin; Huang, Xing-Tao; Ji, Xiao-Bin; Li, Fei; Li, Bai-Bo; Li, Wei-Dong; Liang, Yu-Tie; Liu, Chun-Xiu; Liu, Huai-Min; Liu, Suo; Liu, Ying-Jie; Ma, Qiu-Mei; Ma, Xiang; Mao, Ya-Jun; Mo, Xiao-Hu; Pan, Ming-Hua; Pang, Cai-Ying; Ping, Rong-Gang; Qin, Ya-Hong; Qiu, Jin-Fa; Sun, Sheng-Sen; Sun, Yong-Zhao; Wang, Liang-Liang; Wen, Shuo-Pin; Wu, Ling-Hui; Xie, Yu-Guang; Xu, Min; Yan, Liang; You, Zheng-Yun; Yuan, Chang-Zheng; Yuan, Ye; Zhang, Bing-Yun; Zhang, Chang-Chun; Zhang, Jian-Yong; Zhang, Xue-Yao; Zhang, Yao; Zheng, Yang-Heng; Zhu, Ke-Jun; Zhu, Yong-Sheng; Zhu, Zhi-Li; Zou, Jia-Heng

    2009-10-01

    A track fitting algorithm based on the Kalman filter method has been developed for BESIII of BEPCII. The effects of multiple scattering and energy loss when the charged particles go through the detector, non-uniformity of magnetic field (NUMF) and wire sag, etc., have been carefully handled. This algorithm works well and the performance satisfies the physical requirements tested by the simulation data.

  17. Experimental Evaluation of Design Methods for Hardened Piping Systems.

    DTIC Science & Technology

    prediction capabilities of present day computer methods. The basic pipe elements tested included straight pipes, area changes, elbows , valves, a pump, and...surge tanks. The piping system tested was a closed loop system which contained the following elements: elbows , straight pipes, valves, a pump, and an

  18. An Experimental Method for the Active Learning of Greedy Algorithms

    ERIC Educational Resources Information Center

    Velazquez-Iturbide, J. Angel

    2013-01-01

    Greedy algorithms constitute an apparently simple algorithm design technique, but its learning goals are not simple to achieve.We present a didacticmethod aimed at promoting active learning of greedy algorithms. The method is focused on the concept of selection function, and is based on explicit learning goals. It mainly consists of an…

  19. AN EXPERIMENTAL INVESTIGATION OF MICROPRINGING BY THE OFFSET METHOD, SUPPLEMENT.

    DTIC Science & Technology

    samples produced clearly indicated that the limitation of the offset method had not been reached for lexical material. However, the halftones printed at...more line art and fewer halftones . This preference and trend will favor microprinting by making greater reduction practical, and is another reason

  20. An entrepreneurial physics method and its experimental test

    NASA Astrophysics Data System (ADS)

    Brown, Robert

    2012-02-01

    As faculty in a master's program for entrepreneurial physics and in an applied physics PhD program, I have advised upwards of 40 master and doctoral theses in industrial physics. I have been closely involved with four robust start-up manufacturing companies focused on physics high-technology and I have spent 30 years collaborating with industrial physicists on research and development. Thus I am in a position to reflect on many articles and advice columns centered on entrepreneurship. What about the goals, strategies, resources, skills, and the 10,000 hours needed to be an entrepreneur? What about business plans, partners, financing, patents, networking, salesmanship and regulatory affairs? What about learning new technology, how to solve problems and, in fact, learning innovation itself? At this point, I have my own method to propose to physicists in academia for incorporating entrepreneurship into their research lives. With this method, we do not start with a major invention or discovery, or even with a search for one. The method is based on the training we have, and the teaching we do (even quantum electrodynamics!), as physicists. It is based on the networking we build by 1) providing courses of continuing education for people working in industry and 2) through our undergraduate as well as graduate students who have gone on to work in industry. In fact, if we were to be limited to two words to describe the method, they are ``former students.'' Data from local and international medical imaging manufacturing industry are presented.

  1. Experimental analysis of methods for measuring small mammal populations

    USGS Publications Warehouse

    Stickel, L.F.

    1946-01-01

    SUMMARY: The Peromyscus leucopus on a 17-acre study area were live-trapped, marked, and released over a seven-day period. On the three following nights intensive snap-trapping was done on the central acre of the study plot. The animals caught by snap traps in the central acre represented the population of the central acre and several surrounding acres. By the currently accepted methods of interpreting snap-trap data, the population per acre would be considered to be 23 adults. The live-trap data show that the true population was between six and seven adults per acre. Modern methods of live-trapping are shown to be valid for population studies. Two methods are presented for the conversion of live-trap data into per acre figures. Errors involved in the current use of snap-trap data are discussed and snap-trap methods are shown to be invalid for determining actual population numbers. It should be practical to use a snap-trap quadrant technique to obtain a relative measure or index figure for small mammal populations.

  2. An Experimental Method for the Active Learning of Greedy Algorithms

    ERIC Educational Resources Information Center

    Velazquez-Iturbide, J. Angel

    2013-01-01

    Greedy algorithms constitute an apparently simple algorithm design technique, but its learning goals are not simple to achieve.We present a didacticmethod aimed at promoting active learning of greedy algorithms. The method is focused on the concept of selection function, and is based on explicit learning goals. It mainly consists of an…

  3. Interleaved Carbon Minibeams: An Experimental Radiosurgery Method With Clinical Potential

    SciTech Connect

    Dilmanian, F. Avraham; Rusek, Adam; Fois, Giovanna R.; Olschowka, John; Desnoyers, Nicolle R.; Park, Jane Y.; Dioszegi, Istvan; Dane, Bari; Wang Ruiliang; Tomasi, Dardo; Lee, Hedok; Hurley, Sean D.; Coyle, Patricia K.; Meek, Allen G.; O'Banion, M. Kerry

    2012-10-01

    Purpose: To evaluate the efficacy of 'interleaved carbon minibeams' for ablating a 6.5-mm target in a rabbit brain with little damage to the surrounding brain. The method is based on the well-established tissue-sparing effect of arrays of thin planes of radiation. Methods and Materials: Broad carbon beams from the National Aeronautics and Space Agency Space Radiation Facility at Brookhaven National Laboratory were segmented into arrays of parallel, horizontal, 0.3-mm-thick planar beams (minibeams). The minibeams' gradual broadening in tissues resulted in 0.525-mm beam thickness at the target's proximal side in the spread-out Bragg peak. Interleaving was therefore implemented by choosing a 1.05 mm beam spacing on-center. The anesthetized rabbit, positioned vertically on a stage capable of rotating about a vertical axis, was exposed to arrays from four 90 Degree-Sign angles, with the stage moving up by 0.525 mm in between. This produced a solid radiation field at the target while exposing the nontargeted tissues to single minibeam arrays. The target 'physical' absorbed dose was 40.2 Gy. Results: The rabbit behaved normally during the 6-month observation period. Contrast magnetic resonance imaging and hematoxylin and eosin histology at 6 months showed substantial focal target damage with little damage to the surrounding brain. Conclusion: We plan to evaluate the method's therapeutic efficacy by comparing it with broad-beam carbon therapy in animal models. The method's merits would combine those of carbon therapy (i.e., tight target dose because of the carbon's Bragg-peak, sharp dose falloff, and high relative biological effectiveness at the target), together with the method's low impact on the nontargeted tissues. The method's smaller impact on the nontargeted brain might allow carbon therapy at higher target doses and/or lower normal tissue impact, thus leading to a more effective treatment of radioresistant tumors. It should also make the method more amenable to

  4. New method for detecting singularities in experimental incompressible flows

    NASA Astrophysics Data System (ADS)

    Kuzzay, Denis; Saw, Ewe-Wei; Martins, Fabio J. W. A.; Faranda, Davide; Foucaut, Jean-Marc; Daviaud, François; Dubrulle, Bérengère

    2017-06-01

    We introduce two new criteria based on the work of Duchon and Robert (2000 Nonlinearity 13 249) and Eyink (2006 Phys. Rev. E 74 066302), which allow for the local detection of Navier-Stokes singularities in experimental flows. We discuss the difference between non-dissipative or dissipative Euler quasi-singularities and genuine Navier-Stokes dissipative singularites, and classify them with respect to their Hölder exponent h. We show that our criteria allow us to detect areas in a flow where the velocity field is no more regular than Hölder continuous with some Hölder exponent h ≤slant 1/2 . We illustrate our discussion using classical tomographic particle image velocimetry (TPIV) measurements obtained inside a high Reynolds number flow generated in the boundary layer of a wind tunnel. Our study shows that, in order to detect singularities or quasi-singularities, one does not need to have access to the whole velocity field inside a volume, but can instead look for them from stereoscopic PIV data on a plane. We also provide a discussion about the link between areas detected by our criteria and areas corresponding to large vorticity. We argue that this link might provide either a clue about the genesis of these quasi-singularities or a way to discriminate dissipative Euler quasi-singularities and genuine Navier-Stokes singularities.

  5. Prediction of skin sensitizers using alternative methods to animal experimentation.

    PubMed

    Johansson, Henrik; Lindstedt, Malin

    2014-07-01

    Regulatory frameworks within the European Union demand that chemical substances are investigated for their ability to induce sensitization, an adverse health effect caused by the human immune system in response to chemical exposure. A recent ban on the use of animal tests within the cosmetics industry has led to an urgent need for alternative animal-free test methods that can be used for assessment of chemical sensitizers. To date, no such alternative assay has yet completed formal validation. However, a number of assays are in development and the understanding of the biological mechanisms of chemical sensitization has greatly increased during the last decade. In this MiniReview, we aim to summarize and give our view on the recent progress of method development for alternative assessment of chemical sensitizers. We propose that integrated testing strategies should comprise complementary assays, providing measurements of a wide range of mechanistic events, to perform well-educated risk assessments based on weight of evidence.

  6. An experimental method for the assessment of color simulation tools.

    PubMed

    Lillo, Julio; Alvaro, Leticia; Moreira, Humberto

    2014-07-22

    The Simulcheck method for evaluating the accuracy of color simulation tools in relation to dichromats is described and used to test three color simulation tools: Variantor, Coblis, and Vischeck. A total of 10 dichromats (five protanopes, five deuteranopes) and 10 normal trichromats participated in the current study. Simulcheck includes two psychophysical tasks: the Pseudoachromatic Stimuli Identification task and the Minimum Achromatic Contrast task. The Pseudoachromatic Stimuli Identification task allows determination of the two chromatic angles (h(uv) values) that generate a minimum response in the yellow–blue opponent mechanism and, consequently, pseudoachromatic stimuli (greens or reds). The Minimum Achromatic Contrast task requires the selection of the gray background that produces minimum contrast (near zero change in the achromatic mechanism) for each pseudoachromatic stimulus selected in the previous task (L(R) values). Results showed important differences in the colorimetric transformations performed by the three evaluated simulation tools and their accuracy levels. Vischeck simulation accurately implemented the algorithm of Brettel, Viénot, and Mollon (1997). Only Vischeck appeared accurate (similarity in huv and L(R) values between real and simulated dichromats) and, consequently, could render reliable color selections. It is concluded that Simulcheck is a consistent method because it provided an equivalent pattern of results for huv and L(R) values irrespective of the stimulus set used to evaluate a simulation tool. Simulcheck was also considered valid because real dichromats provided expected huv and LR values when performing the two psychophysical tasks included in this method. © 2014 ARVO.

  7. High-energy particles in space - Experimental methods and techniques

    NASA Astrophysics Data System (ADS)

    Shafer, Iu. G.

    Topics discussed include the space-time variations of cosmic radiation at the geostationary orbit, the nuclear component of solar cosmic rays, excess radiation at high altitudes above the earth, and electron flux with energies exceeding 150 MeV. Consideration is also given to the scattering of charged particles, a detector for measuring soft background X-rays, and the calculation of a detector's electrostatic field by the separation of variables. Methods are discussed for determining gamma-quantum and cosmic ray electron spectra, and for estimating the upper energy bounds of particles accelerated in the vicinity of a rotating neutron star.

  8. Test of Scintillometer Saturation Correction Methods Using Field Experimental Data

    NASA Astrophysics Data System (ADS)

    Kleissl, J.; Hartogensis, O. K.; Gomez, J. D.

    2010-12-01

    Saturation of large aperture scintillometer (LAS) signals can result in sensible heat flux measurements that are biased low. A field study with LASs of different aperture sizes and path lengths was performed to investigate the onset of, and corrections for, signal saturation. Saturation already occurs at {C_n^2 ≈ 0.074 D^{5/3} λ^{1/3} L^{-8/3}}, where {C_n^2} is the structure parameter of the refractive index, D is the aperture size, λ is the wavelength, L is the transect length, which is smaller than theoretically derived saturation limits. At a transect length of 1 km, a height of 2.5 m, and aperture ≈0.15 m the correction factor exceeds 5% already at {C_n^2=2× 10^{-12}m^{-2/3}}, which will affect many practical applications of scintillometry. The Clifford correction method, which only depends on {C_n^2} and the transect geometry, provides good saturation corrections over the range of conditions observed in our study. The saturation correction proposed by Ochs and Hill results in correction factors that are too small in large saturation regimes. An inner length scale dependence of the saturation correction factor was not observed. Thus for practical applications the Clifford correction method should be applied.

  9. Experimental methods for studying microbial survival in extraterrestrial environments.

    PubMed

    Olsson-Francis, Karen; Cockell, Charles S

    2010-01-01

    Microorganisms can be used as model systems for studying biological responses to extraterrestrial conditions; however, the methods for studying their response are extremely challenging. Since the first high altitude microbiological experiment in 1935 a large number of facilities have been developed for short- and long-term microbial exposure experiments. Examples are the BIOPAN facility, used for short-term exposure, and the EXPOSE facility aboard the International Space Station, used for long-term exposure. Furthermore, simulation facilities have been developed to conduct microbiological experiments in the laboratory environment. A large number of microorganisms have been used for exposure experiments; these include pure cultures and microbial communities. Analyses of these experiments have involved both culture-dependent and independent methods. This review highlights and discusses the facilities available for microbiology experiments, both in space and in simulation environments. A description of the microorganisms and the techniques used to analyse survival is included. Finally we discuss the implications of microbiological studies for future missions and for space applications.

  10. Comparison of methods for evaluation of experimentally induced emphysema

    SciTech Connect

    Busch, R.H.; Buschbom, R.L.; Smith, L.G.

    1984-04-01

    Four methods to quantify induced emphysema, in a manner economically applicable to large numbers of animals, are compared by correlation analyses. Lung tissue used was from rats pretreated intratracheally with elastase or saline prior to exposure to air or (NH/sub 4/)/sub 2/SO/sub 4/ or NH/sub 4/NO/sub 3/ aerosols. The most sensitive quantitative evaluation was from mean chord length (MCL) measurements on scanning electron micrographs (SEM). Four-corner and parallel-line grids provided similar results, and reducing sample size to one selected field per lobe yielded a high degree of reliability for MCL measurements. Alveolar-pore perimeter and area (also measured on SEM photographs) were increased by induced emphysema, but were not reliable indicators for degree of pulmonary involvement. Both subjective score (grading the degree of emphysema) and percentage-area-affected determinations indicated the presence of emphysema, but with less sensitivity than MCL measurements. However, these two subgross methods (performed with a dissecting microscope) provided valuable information on the distribution of pulmonary lesions; emphysema was induced in a nonuniform but consistent and progressive pattern in the two lobes of the lung studied. 23 studied.

  11. Decreased mass specific respiration under experimental warming is robust to the microbial biomass method employed.

    Treesearch

    Mark A. Bradford; Matthew D. Wallenstein; Steven D. Allison; Kathleen K. Treseder; Serita D. Frey; Brian W. Watts; Christian A. Davies; Thomas R. Maddox; Jerry M. Melillo; Jacqueline E. Mohan; James F. Reynolds

    2009-01-01

    Hartley et al. question whether reduction in Rmass, under experimental warming, arises because of the biomass method. We show the method they treat as independent yields the same result. We describe why the substrate-depletion hypothesis may not...

  12. Method of generating multiple sets of experimental phantom data.

    PubMed

    Sitek, Arkadiusz; Reutter, Bryan W; Huesman, Ronald H; Gullberg, Grant T

    2006-07-01

    Currently, 2 types of phantoms (physical and computer generated) are used for testing and comparing tomographic reconstruction methods. Data from physical phantoms include all physical effects associated with the detection of radiation. However, with physical phantoms it is difficult to control the number of detected counts, simulate the dynamics of uptake and washout, or create multiple noise realizations of an acquisition. Computer-generated phantoms can overcome some of the disadvantages of physical phantoms, but simulation of all factors affecting the detection of radiation is extremely complex and in some cases impossible. To overcome the problems with both types of phantoms, we developed a physical and computer-generated hybrid phantom that allows the creation of multiple noise realizations of tomographic datasets of the dynamic uptake governed by kinetic models. The method is phantom and camera specific. We applied it to an anthropomorphic torso phantom with a cardiac insert, using a SPECT system with attenuation correction. First, real data were acquired. For each compartment (heart, blood pool, liver, and background) of the physical phantom, large numbers of short tomographic projections were acquired separately for each angle. Sinograms were built from a database of projections by summing the projections of each compartment of the phantom. The amount of activity in each phantom compartment was regulated by the number of added projections. Sinograms corresponding to various projection times, configurations and numbers of detector heads, numbers of noise realizations, numbers of phantom compartments, and compartment-specific time-activity curves in MBq/cm3 were assembled from the database. The acquisition produced a database of 120 projection angles ranging over 360 degrees . For each angle, 300 projections of 0.5 s each were stored in 128 x 128 matrices for easy access. The acquired database was successful in the generation of static and dynamic sinograms

  13. Superconducting Microstrip Antennas: An Experimental Comparison of Two Feeding Methods

    NASA Technical Reports Server (NTRS)

    Richard, Mark A.; Claspy, Paul C.; Bhasin, Kul B.

    1993-01-01

    The recent discovery of high-temperature superconductors (HTSs) has generated a substantial amount of interest in microstrip antenna applications. However, the high permittivity of substrates compatible with HTS causes difficulty in feeding such antennas because of the high patch edge impedance. Two methods for feeding HTS microstrip antennas at K- and Ka-band are examined. Superconducting microstrip antennas that are directly coupled and gas-coupled to a microstrip transmission line have been designed and fabricated on lanthanum aluminate substrates using Y-Ba-Cu-O superconducting thin films. Measurements from these antennas, including input impedance, bandwidth, efficiency, and patterns, are presented and compared with published models. The measured results demonstrate that usable antennas can be constructed using either of these architectures, although the antennas suffer from narrow bandwidths. In each case, the HTS antenna shows a substantial improvement over an identical antenna made with normal metals

  14. Superconducting microstrip antennas - An experimental comparison of two feeding methods

    NASA Technical Reports Server (NTRS)

    Richard, M. A.; Bhasin, Kul B.; Claspy, Paul C.

    1993-01-01

    The recent discovery of high-temperature superconductors (HTSs) has generated a substantial amount of interest in microstrip antenna applications. However, the high permittivity of substrates compatible with HTS causes difficulty in feeding such antennas because of the high patch edge impedance. Two methods for feeding HTS microstrip antennas at K- and Ka-band are examined. Superconducting microstrip antennas that are directly coupled and gap-coupled to a microstrip transmission line have been designed and fabricated on lanthanum aluminate substrates using Y-Ba-Cu-O superconducting thin films. Measurements from these antennas, including input impedance, bandwidth, efficiency, and patterns, are presented and compared with published models. The measured results demonstrate that usable antennas can be constructed using either of these architectures, although the antennas suffer from narrow bandwidths. In each case, the HTS antenna shows a substantial improvement over an identical antenna made with normal metals.

  15. Experimental Validation for Hot Stamping Process by Using Taguchi Method

    NASA Astrophysics Data System (ADS)

    Fawzi Zamri, Mohd; Lim, Syh Kai; Razlan Yusoff, Ahmad

    2016-02-01

    Due to the demand for reduction in gas emissions, energy saving and producing safer vehicles has driven the development of Ultra High Strength Steel (UHSS) material. To strengthen UHSS material such as boron steel, it needed to undergo a process of hot stamping for heating at certain temperature and time. In this paper, Taguchi method is applied to determine the appropriate parameter of thickness, heating temperature and heating time to achieve optimum strength of boron steel. The experiment is conducted by using flat square shape of hot stamping tool with tensile dog bone as a blank product. Then, the value of tensile strength and hardness is measured as response. The results showed that the lower thickness, higher heating temperature and heating time give the higher strength and hardness for the final product. In conclusion, boron steel blank are able to achieve up to 1200 MPa tensile strength and 650 HV of hardness.

  16. Superconducting microstrip antennas - An experimental comparison of two feeding methods

    NASA Technical Reports Server (NTRS)

    Richard, M. A.; Bhasin, Kul B.; Claspy, Paul C.

    1993-01-01

    The recent discovery of high-temperature superconductors (HTSs) has generated a substantial amount of interest in microstrip antenna applications. However, the high permittivity of substrates compatible with HTS causes difficulty in feeding such antennas because of the high patch edge impedance. Two methods for feeding HTS microstrip antennas at K- and Ka-band are examined. Superconducting microstrip antennas that are directly coupled and gap-coupled to a microstrip transmission line have been designed and fabricated on lanthanum aluminate substrates using Y-Ba-Cu-O superconducting thin films. Measurements from these antennas, including input impedance, bandwidth, efficiency, and patterns, are presented and compared with published models. The measured results demonstrate that usable antennas can be constructed using either of these architectures, although the antennas suffer from narrow bandwidths. In each case, the HTS antenna shows a substantial improvement over an identical antenna made with normal metals.

  17. Superconducting Microstrip Antennas: An Experimental Comparison of Two Feeding Methods

    NASA Technical Reports Server (NTRS)

    Richard, Mark A.; Claspy, Paul C.; Bhasin, Kul B.

    1993-01-01

    The recent discovery of high-temperature superconductors (HTSs) has generated a substantial amount of interest in microstrip antenna applications. However, the high permittivity of substrates compatible with HTS causes difficulty in feeding such antennas because of the high patch edge impedance. Two methods for feeding HTS microstrip antennas at K- and Ka-band are examined. Superconducting microstrip antennas that are directly coupled and gas-coupled to a microstrip transmission line have been designed and fabricated on lanthanum aluminate substrates using Y-Ba-Cu-O superconducting thin films. Measurements from these antennas, including input impedance, bandwidth, efficiency, and patterns, are presented and compared with published models. The measured results demonstrate that usable antennas can be constructed using either of these architectures, although the antennas suffer from narrow bandwidths. In each case, the HTS antenna shows a substantial improvement over an identical antenna made with normal metals

  18. Superconducting microstrip antennas: An experimental comparison of two feeding methods

    SciTech Connect

    Richard, M.A.; Claspy, P.C. ); Bhasin, K.B. . Lewis Research Center)

    1993-07-01

    The recent discovery of high-temperature superconductors (HTS's) has generated a substantial amount of interest in microstrip antenna applications. However, the high permittivity of substrates compatible with HTS causes difficulty in feeding such antennas because of the high patch edge impedance. In this paper, two methods for feeding HTS microstrip antennas at K and Ka-band are examined. Superconducting microstrip antennas that are directly coupled and gap-coupled to a microstrip transmission line have been designed and fabricated on lanthanum aluminate substrates using Y-Ba-Cu-O superconducting thin films. Measurements from these antennas, including input impedance, bandwidth, efficiency, and patterns, are presented and compared with published models. The measured results demonstrate that usable antennas can be constructed using either of these architectures, although the antennas suffer from narrow bandwidths. In each case, the HTS antenna shows a substantial improvement over an identical antenna made with normal metals.

  19. Experimental Methods to Preserve Male Fertility and Treat Male Infertility

    PubMed Central

    Gassei, Kathrin; Orwig, Kyle E.

    2016-01-01

    Infertility is a prevalent condition that has insidious impacts on the infertile individuals, their families and society that extend far beyond the inability to have a biological child. Lifestyle changes, fertility treatments and assisted reproductive technologies are available to help many infertile couples achieve their reproductive goals. All of these technologies require that the infertile individual is able to produce at least a small number of functional gametes (eggs or sperm). It is not possible for a person who does not produce gametes to have a biological child. This review focuses on the infertile man and describes several stem cell-based methods and gene therapy approaches that are in the research pipeline and may lead to new fertility treatment options for azoospermic men. PMID:26746133

  20. Translocations of amphibians: Proven management method or experimental technique

    USGS Publications Warehouse

    Seigel, Richard A.; Dodd, C. Kenneth

    2002-01-01

    In an otherwise excellent review of metapopulation dynamics in amphibians, Marsh and Trenham (2001) make the following provocative statements (emphasis added): If isolation effects occur primarily in highly disturbed habitats, species translocations may be necessary to promote local and regional population persistence. Because most amphibians lack parental care, they areprime candidates for egg and larval translocations. Indeed, translocations have already proven successful for several species of amphibians. Where populations are severely isolated, translocations into extinct subpopulations may be the best strategy to promote regional population persistence. We take issue with these statements for a number of reasons. First, the authors fail to cite much of the relevant literature on species translocations in general and for amphibians in particular. Second, to those unfamiliar with current research in amphibian conservation biology, these comments might suggest that translocations are a proven management method. This is not the case, at least in most instances where translocations have been evaluated for an appropriate period of time. Finally, the authors fail to point out some of the negative aspects of species translocation as a management method. We realize that Marsh and Trenham's paper was not concerned primarily with translocations. However, because Marsh and Trenham (2001) made specific recommendations for conservation planners and managers (many of whom are not herpetologists or may not be familiar with the pertinent literature on amphibians), we believe that it is essential to point out that not all amphibian biologists are as comfortable with translocations as these authors appear to be. We especially urge caution about advocating potentially unproven techniques without a thorough review of available options.

  1. Teaching Experimental Method Using the Feature-Present/Feature-Absent Effect

    ERIC Educational Resources Information Center

    Balch, William R.

    2010-01-01

    To determine whether a classroom experiment improved the learning of experimental method, at the start of the semester 2 introductory psychology classes took a 10-question multiple-choice pretest on experimental method. Two days later, before the instructor covered the relevant material in the course, 1 class took part in a classroom experiment on…

  2. Topics on Test Methods for Space Systems and Operations Safety: Applicability of Experimental Data

    NASA Technical Reports Server (NTRS)

    Hirsch, David B.

    2009-01-01

    This viewgraph presentation reviews topics on test methods for space systems and operations safety through experimentation and analysis. The contents include: 1) Perception of reality through experimentation and analysis; 2) Measurements, methods, and correlations with real life; and 3) Correlating laboratory aerospace materials flammability data with data in spacecraft environments.

  3. Comparison of Nonoverlap Methods for Identifying Treatment Effect in Single-Subject Experimental Research

    ERIC Educational Resources Information Center

    Rakap, Salih; Snyder, Patricia; Pasia, Cathleen

    2014-01-01

    Debate is occurring about which result interpretation aides focused on examining the experimental effect should be used in single-subject experimental research. In this study, we examined seven nonoverlap methods and compared results using each method to judgments of two visual analysts. The data sources for the present study were 36 studies…

  4. Teaching Experimental Method Using the Feature-Present/Feature-Absent Effect

    ERIC Educational Resources Information Center

    Balch, William R.

    2010-01-01

    To determine whether a classroom experiment improved the learning of experimental method, at the start of the semester 2 introductory psychology classes took a 10-question multiple-choice pretest on experimental method. Two days later, before the instructor covered the relevant material in the course, 1 class took part in a classroom experiment on…

  5. Comparison of Nonoverlap Methods for Identifying Treatment Effect in Single-Subject Experimental Research

    ERIC Educational Resources Information Center

    Rakap, Salih; Snyder, Patricia; Pasia, Cathleen

    2014-01-01

    Debate is occurring about which result interpretation aides focused on examining the experimental effect should be used in single-subject experimental research. In this study, we examined seven nonoverlap methods and compared results using each method to judgments of two visual analysts. The data sources for the present study were 36 studies…

  6. Experimental cosmology using fast parallel N-body methods

    NASA Astrophysics Data System (ADS)

    Warren, Michael S.

    This dissertation describes a parallel treecode N-body algorithm and a number of simulations which have been performed on massively parallel computers. We use the results of these simulations (which use between 1 and 17 million particles each) to investigate the structure, kinematics, shapes, masses, spatial correlations, and relative pairwise velocity dispersions of dark matter halos. Using cold dark matter (CDM) initial conditions normalized to the anisotropies detected by the COBE satellite, we show that the mass function and spatial distribution of halos is compatible with the observations. We also show the value of the relative pair-wise velocity dispersion sigma(nu), used as evidence against COBE-normalized CDM models, is significantly lower for halos than for individual particles. When the observational methods of extracting sigma(nu) are applied to catalogs obtained from the numerical experiments, estimates differ significantly between different observation-sized samples, and overlap observational estimates. We also study smaller systems which form by gravitational collapse from scale-free and more general Gaussian initial density perturbations. We analyze the structure and kinematics of the approximately 102 largest relaxed halos in a number of simulations. A typical halo is a triaxial spheroid which tends to be more often prolate than oblate. These shapes are maintained by anisotropic velocity dispersion rather than by angular momentum (spin parameter lambda approximately 0.05). Nevertheless, there is a significant tendency for the total angular momentum vector to be aligned with the minor axis of the density distribution. In addition, we report on an efficient adaptive parallel N-body method which we have designed and implemented. The algorithm computes the forces on an arbitrary distribution of bodies in a time which scales as N log N with the particle number. The accuracy of the force calculations is analytically bounded, and can be adjusted via a user

  7. The agencies method for coalition formation in experimental games

    PubMed Central

    Nash, John F.; Nagel, Rosemarie; Ockenfels, Axel; Selten, Reinhard

    2012-01-01

    In society, power is often transferred to another person or group. A previous work studied the evolution of cooperation among robot players through a coalition formation game with a non-cooperative procedure of acceptance of an agency of another player. Motivated by this previous work, we conduct a laboratory experiment on finitely repeated three-person coalition formation games. Human players with different strength according to the coalition payoffs can accept a transfer of power to another player, the agent, who then distributes the coalition payoffs. We find that the agencies method for coalition formation is quite successful in promoting efficiency. However, the agent faces a tension between short-term incentives of not equally distributing the coalition payoff and the long-term concern to keep cooperation going. In a given round, the strong player in our experiment often resolves this tension approximately in line with the Shapley value and the nucleolus. Yet aggregated over all rounds, the payoff differences between players are rather small, and the equal division of payoffs predicts about 80% of all groups best. One reason is that the voting procedure appears to induce a balance of power, independent of the individual player's strength: Selfish subjects tend to be voted out of their agency and are further disciplined by reciprocal behaviors. PMID:23175792

  8. Methods in systems biology of experimental methamphetamine drug abuse.

    PubMed

    Kobeissy, Firas H; Sadasivan, Shankar; Buchanan, Melinda; Zhang, Zhiqun; Gold, Mark S; Wang, Kevin K W

    2010-01-01

    The use of methamphetamine (METH) as recreational drugs is a growing problem worldwide with recent concerns that it might cause long-lasting harmful effects to the human brain. METH is an illicit drug that is known to exert neurotoxic effects on both dopaminergic and serotonergic neural systems. Our laboratory has been studying the biochemical mechanisms underlying METH-induced neurotoxic effects both in vivo and in vitro. Our psychoproteomics METH abuse research focuses on the global alteration of cortical protein expression in rats treated with acute METH. In our analysis, an altered protein expression was identified using a multistep protein separation/proteomic platform. Differential changes of the selected proteins were further confirmed by quantitative immunoblotting. Our study identified 82 differentially expressed proteins, 40 of which were downregulated and 42 of which were upregulated post acute METH treatment. In this chapter, we describe the current protocols for the neuronal cell culture in vitro and the in vivo rat model of acute METH treatment (4 x 10 mg/kg) coupled with the description current bioinformatics analysis utilized to analyze the different implicated interaction protein/gene maps that reflected on the altered functions observed. These methods and protocols are discussed in the paradigm of the acute model of METH drug abuse and neuronal cell culture and can be applied on other models of substance abuse such as on MDMA or cocaine.

  9. The agencies method for coalition formation in experimental games.

    PubMed

    Nash, John F; Nagel, Rosemarie; Ockenfels, Axel; Selten, Reinhard

    2012-12-11

    In society, power is often transferred to another person or group. A previous work studied the evolution of cooperation among robot players through a coalition formation game with a non-cooperative procedure of acceptance of an agency of another player. Motivated by this previous work, we conduct a laboratory experiment on finitely repeated three-person coalition formation games. Human players with different strength according to the coalition payoffs can accept a transfer of power to another player, the agent, who then distributes the coalition payoffs. We find that the agencies method for coalition formation is quite successful in promoting efficiency. However, the agent faces a tension between short-term incentives of not equally distributing the coalition payoff and the long-term concern to keep cooperation going. In a given round, the strong player in our experiment often resolves this tension approximately in line with the Shapley value and the nucleolus. Yet aggregated over all rounds, the payoff differences between players are rather small, and the equal division of payoffs predicts about 80% of all groups best. One reason is that the voting procedure appears to induce a balance of power, independent of the individual player's strength: Selfish subjects tend to be voted out of their agency and are further disciplined by reciprocal behaviors.

  10. Method for Making Measurements of the Post-Combustion Residence Time in a Gas Turbine Engine

    NASA Technical Reports Server (NTRS)

    Miles, Jeffrey H. (Inventor)

    2017-01-01

    A method of measuring a residence time in a gas-turbine engine is disclosed that includes measuring a combustor pressure signal at a combustor entrance and a turbine exit pressure signal at a turbine exit. The method further includes computing a cross-spectrum function between the combustor pressure signal and the turbine exit pressure signal, calculating a slope of the cross-spectrum function, shifting the turbine exit pressure signal an amount corresponding to a time delay between the measurement of the combustor pressure signal and the turbine exit pressure signal, and recalculating the slope of the cross-spectrum function until the slope reaches zero.

  11. Scaffolded Instruction Improves Student Understanding of the Scientific Method & Experimental Design

    ERIC Educational Resources Information Center

    D'Costa, Allison R.; Schlueter, Mark A.

    2013-01-01

    Implementation of a guided-inquiry lab in introductory biology classes, along with scaffolded instruction, improved students' understanding of the scientific method, their ability to design an experiment, and their identification of experimental variables. Pre- and postassessments from experimental versus control sections over three semesters…

  12. Scaffolded Instruction Improves Student Understanding of the Scientific Method & Experimental Design

    ERIC Educational Resources Information Center

    D'Costa, Allison R.; Schlueter, Mark A.

    2013-01-01

    Implementation of a guided-inquiry lab in introductory biology classes, along with scaffolded instruction, improved students' understanding of the scientific method, their ability to design an experiment, and their identification of experimental variables. Pre- and postassessments from experimental versus control sections over three semesters…

  13. A new experimental method for the accelerated characterization of composite materials

    NASA Technical Reports Server (NTRS)

    Yeow, Y. T.; Morris, D. H.; Brinson, H. F.

    1978-01-01

    The use of composite materials for a variety of practical structural applications is presented and the need for an accelerated characterization procedure is assessed. A new experimental and analytical method is presented which allows the prediction of long term properties from short term tests. Some preliminary experimental results are presented.

  14. LEARNING TO READ SCIENTIFIC RUSSIAN BY THE THREE QUESTION EXPERIMENTAL (3QX) METHOD.

    ERIC Educational Resources Information Center

    ALFORD, M.H.T.

    A NEW METHOD FOR LEARNING TO READ TECHNICAL LITERATURE IN A FOREIGN LANGUAGE IS BEING DEVELOPED AND TESTED AT THE LANGUAGE CENTRE OF THE UNIVERSITY OF ESSEX, COLCHESTER, ENGLAND. THE METHOD IS CALLED "THREE QUESTION EXPERIMENTAL METHOD (3QX)," AND IT HAS BEEN USED IN THREE COURSES FOR TEACHING SCIENTIFIC RUSSIAN TO PHYSICISTS. THE THREE…

  15. Development of Improved Microwave Dielectric Materials and Devices using Advanced Experimental and Theoretical Methods

    DTIC Science & Technology

    2008-04-17

    REPORT Development of improved microwave dielectric materials and devices using advanced experimental and theoretical methods 14. ABSTRACT 16. SECURITY... methods Report Title ABSTRACT Our work has made important progress towards developing a fundamental understanding of the microscopic mechanism that causes...electromagnetic Band Gap Filters using advanced ceramic injection molding methods ”, Semiconductor Research Corporation Packaging and Interconnect Summer

  16. Choices for Studying Choice: Assessing Charter School Effectiveness Using Two Quasi-Experimental Methods

    ERIC Educational Resources Information Center

    Davis, Devora H.; Raymond, Margaret E.

    2012-01-01

    Two quasi-experimental methods--fixed effects (FE) and virtual control records (VCR)--were used to measure charter schooling in 14 states and two districts. The new VCR method uses all available observable charter student characteristics and prior performance to create a composite comparison record. A head-to-head comparison of the FE and VCR…

  17. Choices for Studying Choice: Assessing Charter School Effectiveness Using Two Quasi-Experimental Methods

    ERIC Educational Resources Information Center

    Davis, Devora H.; Raymond, Margaret E.

    2012-01-01

    Two quasi-experimental methods--fixed effects (FE) and virtual control records (VCR)--were used to measure charter schooling in 14 states and two districts. The new VCR method uses all available observable charter student characteristics and prior performance to create a composite comparison record. A head-to-head comparison of the FE and VCR…

  18. Survey of engineering computational methods and experimental programs for estimating supersonic missile aerodynamic characteristics

    NASA Technical Reports Server (NTRS)

    Sawyer, W. C.; Allen, J. M.; Hernandez, G.; Dillenius, M. F. E.; Hemsch, M. J.

    1982-01-01

    This paper presents a survey of engineering computational methods and experimental programs used for estimating the aerodynamic characteristics of missile configurations. Emphasis is placed on those methods which are suitable for preliminary design of conventional and advanced concepts. An analysis of the technical approaches of the various methods is made in order to assess their suitability to estimate longitudinal and/or lateral-directional characteristics for different classes of missile configurations. Some comparisons between the predicted characteristics and experimental data are presented. These comparisons are made for a large variation in flow conditions and model attitude parameters. The paper also presents known experimental research programs developed for the specific purpose of validating analytical methods and extending the capability of data-base programs.

  19. Survey of engineering computational methods and experimental programs for estimating supersonic missile aerodynamic characteristics

    NASA Technical Reports Server (NTRS)

    Sawyer, W. C.; Allen, J. M.; Hernandez, G.; Dillenius, M. F. E.; Hemsch, M. J.

    1982-01-01

    This paper presents a survey of engineering computational methods and experimental programs used for estimating the aerodynamic characteristics of missile configurations. Emphasis is placed on those methods which are suitable for preliminary design of conventional and advanced concepts. An analysis of the technical approaches of the various methods is made in order to assess their suitability to estimate longitudinal and/or lateral-directional characteristics for different classes of missile configurations. Some comparisons between the predicted characteristics and experimental data are presented. These comparisons are made for a large variation in flow conditions and model attitude parameters. The paper also presents known experimental research programs developed for the specific purpose of validating analytical methods and extending the capability of data-base programs.

  20. Automatic query generation using word embeddings for retrieving passages describing experimental methods

    PubMed Central

    Aydın, Ferhat; Hüsünbeyi, Zehra Melce; Özgür, Arzucan

    2017-01-01

    Information regarding the physical interactions among proteins is crucial, since protein–protein interactions (PPIs) are central for many biological processes. The experimental techniques used to verify PPIs are vital for characterizing and assessing the reliability of the identified PPIs. A lot of information about PPIs and the experimental methods are only available in the text of the scientific publications that report them. In this study, we approach the problem of identifying passages with experimental methods for physical interactions between proteins as an information retrieval search task. The baseline system is based on query matching, where the queries are generated by utilizing the names (including synonyms) of the experimental methods in the Proteomics Standard Initiative–Molecular Interactions (PSI-MI) ontology. We propose two methods, where the baseline queries are expanded by including additional relevant terms. The first method is a supervised approach, where the most salient terms for each experimental method are obtained by using the term frequency–relevance frequency (tf.rf) metric over 13 articles from our manually annotated data set of 30 full text articles, which is made publicly available. On the other hand, the second method is an unsupervised approach, where the queries for each experimental method are expanded by using the word embeddings of the names of the experimental methods in the PSI-MI ontology. The word embeddings are obtained by utilizing a large unlabeled full text corpus. The proposed methods are evaluated on the test set consisting of 17 articles. Both methods obtain higher recall scores compared with the baseline, with a loss in precision. Besides higher recall, the word embeddings based approach achieves higher F-measure than the baseline and the tf.rf based methods. We also show that incorporating gene name and interaction keyword identification leads to improved precision and F-measure scores for all three evaluated

  1. Automatic query generation using word embeddings for retrieving passages describing experimental methods.

    PubMed

    Aydın, Ferhat; Hüsünbeyi, Zehra Melce; Özgür, Arzucan

    2017-01-01

    Information regarding the physical interactions among proteins is crucial, since protein-protein interactions (PPIs) are central for many biological processes. The experimental techniques used to verify PPIs are vital for characterizing and assessing the reliability of the identified PPIs. A lot of information about PPIs and the experimental methods are only available in the text of the scientific publications that report them. In this study, we approach the problem of identifying passages with experimental methods for physical interactions between proteins as an information retrieval search task. The baseline system is based on query matching, where the queries are generated by utilizing the names (including synonyms) of the experimental methods in the Proteomics Standard Initiative-Molecular Interactions (PSI-MI) ontology. We propose two methods, where the baseline queries are expanded by including additional relevant terms. The first method is a supervised approach, where the most salient terms for each experimental method are obtained by using the term frequency-relevance frequency (tf.rf) metric over 13 articles from our manually annotated data set of 30 full text articles, which is made publicly available. On the other hand, the second method is an unsupervised approach, where the queries for each experimental method are expanded by using the word embeddings of the names of the experimental methods in the PSI-MI ontology. The word embeddings are obtained by utilizing a large unlabeled full text corpus. The proposed methods are evaluated on the test set consisting of 17 articles. Both methods obtain higher recall scores compared with the baseline, with a loss in precision. Besides higher recall, the word embeddings based approach achieves higher F-measure than the baseline and the tf.rf based methods. We also show that incorporating gene name and interaction keyword identification leads to improved precision and F-measure scores for all three evaluated methods

  2. Calibration of Aeroelastic Prediction Methods: Comparison with Experimental Results on a Single Stage Compressor Blisk

    DTIC Science & Technology

    2005-10-01

    RTO UNCLASSIFIED/UNLIMITED Calibration of Aeroelastic Prediction Methods: Comparison with Experimental Results on a Single Stage Compressor Blisk ...presents a comparison between the measured and computed forced response of a high-pressure compressor Blisk for aeronautical applications. Measurements...Experimental Results on a Single Stage Compressor Blisk . In Evaluation, Control and Prevention of High Cycle Fatigue in Gas Turbine Engines for Land, Sea and

  3. Prediction of sonic boom from experimental near-field overpressure data. Volume 1: Method and results

    NASA Technical Reports Server (NTRS)

    Glatt, C. R.; Hague, D. S.; Reiners, S. J.

    1975-01-01

    A computerized procedure for predicting sonic boom from experimental near-field overpressure data has been developed. The procedure extrapolates near-field pressure signatures for a specified flight condition to the ground by the Thomas method. Near-field pressure signatures are interpolated from a data base of experimental pressure signatures. The program is an independently operated ODIN (Optimal Design Integration) program which obtains flight path information from other ODIN programs or from input.

  4. Experimental Verification of a Systematic Method for Identifying Contact-Dynamics Model Parameters

    DTIC Science & Technology

    2007-07-31

    demonstrated by simulation study (Weber, Patel, Ma and Sharf 2006). This project is aimed at experimental investigation of this method. Because of the...experimentally investigated on this project has been described in (Weber, Patel, Ma, and Sharf 2006). It uses the linear estimation technology to...and contact-surface deformation (i.e., deflection of the “spring”); exponent λ depends on contact geometry (Gilardi and Sharf 2002); and n is an out

  5. Comparison between experimental and computational methods for scattering anisotropy coefficient determination in dental-resin composites

    NASA Astrophysics Data System (ADS)

    Fernández-Oliveras, Alicia; Carrasco, Irene M.; Ghinea, Razvan; Pérez, María M.; Rubiño, Manuel

    2012-06-01

    Understanding the behaviour of light propagation in biological materials is essential for biomedical engineering and its applications. Among the key optical properties of biological media is the angular distribution of the scattered light, characterized by the average cosine of the scattering angle, called the scattering anisotropy coefficient (g). The value of g can be determined by experimentally irradiating the material with a laser beam and making angular-scattering measurements in a goniometer. In this work, an experimental technique was used to determine g by means of goniometric measurements of the laser light scattered off two different dental-resin composites (classified as nano and hybrid). To assess the accuracy of the experimental method, a Mie theory-based computational model was used. Independent measurements were used to determine some of the required input parameters for computation of the theoretical model. The g values estimated with the computational method (nano-filled: 0.9399; hybrid: 0.8975) and the values calculated with the experimental method presented (nano-filled: 0.98297 +/- 0.00021; hybrid: 0.95429 +/- 0.00014) agreed well for both dental resins, with slightly higher experimental values. The higher experimental values may indicate that the scattering particle causes more narrow-angle scattering than does a perfect sphere of equal volume, assuming that with more spherical scattering particles the scattering anisotropy coefficient increases. Since g represents the angular distribution of the scattered light, values provided by both the experimental and the computational methods show a strongly forward-directed scattering in the dental resins studied, more pronounced in the nano-filled composite than in the hybrid composite.

  6. Evaluating the osseointegration of nanostructured titanium implants in animal models: Current experimental methods and perspectives (Review).

    PubMed

    Babuska, Vaclav; Moztarzadeh, Omid; Kubikova, Tereza; Moztarzadeh, Amin; Hrusak, Daniel; Tonar, Zbynek

    2016-09-15

    The aim of this paper is to review the experimental methods currently being used to evaluate the osseointegration of nanostructured titanium implants using animal models. The material modifications are linked to the biocompatibility of various types of oral implants, such as laser-treated, acid-etched, plasma-coated, and sand-blasted surface modifications. The types of implants are reviewed according to their implantation site (endoosseous, subperiosteal, and transosseous implants). The animal species and target bones used in experimental implantology are carefully compared in terms of the ratio of compact to spongy bone. The surgical technique in animal experiments is briefly described, and all phases of the histological evaluation of osseointegration are described in detail, including harvesting tissue samples, processing undemineralized ground sections, and qualitative and quantitative histological assessment of the bone-implant interface. The results of histological staining methods used in implantology are illustrated and compared. A standardized and reproducible technique for stereological quantification of bone-implant contact is proposed and demonstrated. In conclusion, histological evaluation of the experimental osseointegration of dental implants requires careful selection of the experimental animals, bones, and implantation sites. It is also advisable to use larger animal models and older animals with a slower growth rate rather than small or growing experimental animals. Bones with a similar ratio of compact to spongy bone, such as the human maxilla and mandible, are preferred. A number of practical recommendations for the experimental procedures, harvesting of samples, tissue processing, and quantitative histological evaluations are provided.

  7. Highly Efficient Design-of-Experiments Methods for Combining CFD Analysis and Experimental Data

    NASA Technical Reports Server (NTRS)

    Anderson, Bernhard H.; Haller, Harold S.

    2009-01-01

    It is the purpose of this study to examine the impact of "highly efficient" Design-of-Experiments (DOE) methods for combining sets of CFD generated analysis data with smaller sets of Experimental test data in order to accurately predict performance results where experimental test data were not obtained. The study examines the impact of micro-ramp flow control on the shock wave boundary layer (SWBL) interaction where a complete paired set of data exist from both CFD analysis and Experimental measurements By combining the complete set of CFD analysis data composed of fifteen (15) cases with a smaller subset of experimental test data containing four/five (4/5) cases, compound data sets (CFD/EXP) were generated which allows the prediction of the complete set of Experimental results No statistical difference were found to exist between the combined (CFD/EXP) generated data sets and the complete Experimental data set composed of fifteen (15) cases. The same optimal micro-ramp configuration was obtained using the (CFD/EXP) generated data as obtained with the complete set of Experimental data, and the DOE response surfaces generated by the two data sets were also not statistically different.

  8. A new experimental design method to optimize formulations focusing on a lubricant for hydrophilic matrix tablets.

    PubMed

    Choi, Du Hyung; Shin, Sangmun; Khoa Viet Truong, Nguyen; Jeong, Seong Hoon

    2012-09-01

    A robust experimental design method was developed with the well-established response surface methodology and time series modeling to facilitate the formulation development process with magnesium stearate incorporated into hydrophilic matrix tablets. Two directional analyses and a time-oriented model were utilized to optimize the experimental responses. Evaluations of tablet gelation and drug release were conducted with two factors x₁ and x₂: one was a formulation factor (the amount of magnesium stearate) and the other was a processing factor (mixing time), respectively. Moreover, different batch sizes (100 and 500 tablet batches) were also evaluated to investigate an effect of batch size. The selected input control factors were arranged in a mixture simplex lattice design with 13 experimental runs. The obtained optimal settings of magnesium stearate for gelation were 0.46 g, 2.76 min (mixing time) for a 100 tablet batch and 1.54 g, 6.51 min for a 500 tablet batch. The optimal settings for drug release were 0.33 g, 7.99 min for a 100 tablet batch and 1.54 g, 6.51 min for a 500 tablet batch. The exact ratio and mixing time of magnesium stearate could be formulated according to the resulting hydrophilic matrix tablet properties. The newly designed experimental method provided very useful information for characterizing significant factors and hence to obtain optimum formulations allowing for a systematic and reliable experimental design method.

  9. Advanced Life Analysis Methods. Volume 3. Experimental Evaluation of Crack Growth Analysis Methods for Attachment Lugs

    DTIC Science & Technology

    1984-09-17

    Structural Lugs 10 6.00 TETM TESX, MARI LOCKHEED L𔃼.0 GRUP IIhA AND 2Rii * 2~~~~.0 .RUPINI .01 .05 1 .2 .5. 9 99PROABLTY F*ý,r 1-40 4oprsno R ato nTs rga...monitor loads and perform failsafe functions . A sinewave function generator provides load commands to the servo loop and a calibrated amplitude measurement...Simple Compounding Solution o 2-D Cracked Finite Element Procedure o Green’s Function Method 0 3-D Cracked Finite Element PrTocedure Parameters and

  10. An improved mixed numerical-experimental method for stress field calculation

    NASA Astrophysics Data System (ADS)

    Lopes, H. M. R.; Guedes, R. M.; Vaz, M. A.

    2007-07-01

    In this work a numerical-experimental method is used to study the dynamic behavior of an aluminum plate subjected to a small mass impact. The out-of-plane displacements, due to transient bending wave propagation, were assessed for successive time instants, using double pulse TV-holography, also known as pulsed ESPI. The experimental setup and the image processing methods were improved to allow the calculation of the plate transient stress field. Integral transforms are used to obtain the strain fields from spatial derivatives of displacements noisy data. A numerical simulation of the plate transient response was carried out with FEM Ansys ®. For this purpose a PZT transducer was used to record the impact force history, which was inputted in the numerical model. Finally, the comparisons between numerical and experimental results are presented in order to validate the present methodology.

  11. High fidelity studies of exploding foil initiator bridges, Part 1: Experimental method

    NASA Astrophysics Data System (ADS)

    Bowden, Mike; Neal, William

    2017-01-01

    Simulations of high voltage detonators, such as Exploding Bridgewire (EBW) and Exploding Foil Initiators (EFI), have historically been simple, often empirical, one-dimensional models capable of predicting parameters such as current, voltage and in the case of EFIs, flyer velocity. Correspondingly, experimental methods have in general been limited to the same parameters. With the advent of complex, first principles magnetohydrodynamic codes such as ALEGRA and ALE-MHD, it is now possible to simulate these components in three dimensions, predicting a much greater range of parameters than before. A significant improvement in experimental capability was therefore required to ensure these simulations could be adequately validated. In this first paper of a three part study, the experimental method for determining the current, voltage, flyer velocity and multi-dimensional profile of detonator components is presented. This improved capability, along with high fidelity simulations, offer an opportunity to gain a greater understanding of the processes behind the functioning of EBW and EFI detonators.

  12. Recent mouse and rat methods for the study of experimental oral candidiasis

    PubMed Central

    Costa, Anna CBP; Pereira, Cristiane A; Junqueira, Juliana C; Jorge, Antonio OC

    2013-01-01

    The Candida genus expresses virulence factors that, when combined with immunosuppression and other risk factors, can cause different manifestations of oral candidiasis. The treatment of mucosal infections caused by Candida and the elucidation of the disease process have proven challenging. Therefore, the study of experimentally induced oral candidiasis in rats and mice is useful to clarify the etiopathology of this condition, improve diagnosis, and search for new therapeutic options because the disease process in these animals is similar to that of human candidiasis lesions. Here, we describe and discuss new studies involving rat and mouse models of oral candidiasis with respect to methods for inducing experimental infection, methods for evaluating the development of experimental candidiasis, and new treatment strategies for oral candidiasis. PMID:23715031

  13. Recent mouse and rat methods for the study of experimental oral candidiasis.

    PubMed

    Costa, Anna C B P; Pereira, Cristiane A; Junqueira, Juliana C; Jorge, Antonio O C

    2013-07-01

    The Candida genus expresses virulence factors that, when combined with immunosuppression and other risk factors, can cause different manifestations of oral candidiasis. The treatment of mucosal infections caused by Candida and the elucidation of the disease process have proven challenging. Therefore, the study of experimentally induced oral candidiasis in rats and mice is useful to clarify the etiopathology of this condition, improve diagnosis, and search for new therapeutic options because the disease process in these animals is similar to that of human candidiasis lesions. Here, we describe and discuss new studies involving rat and mouse models of oral candidiasis with respect to methods for inducing experimental infection, methods for evaluating the development of experimental candidiasis, and new treatment strategies for oral candidiasis.

  14. Design and structural verification of locomotive bogies using combined analytical and experimental methods

    NASA Astrophysics Data System (ADS)

    Manea, I.; Popa, G.; Girnita, I.; Prenta, G.

    2015-11-01

    The paper presents a practical methodology for design and structural verification of the locomotive bogie frames using a modern software package for design, structural verification and validation through combined, analytical and experimental methods. In the initial stage, the bogie geometry is imported from a CAD program into a finite element analysis program, such as Ansys. The analytical model validation is done by experimental modal analysis carried out on a finished bogie frame. The bogie frame own frequencies and own modes by both experimental and analytic methods are determined and the correlation analysis of the two types of models is performed. If the results are unsatisfactory, the structural optimization should be performed. If the results are satisfactory, the qualification procedures follow by static and fatigue tests carried out in a laboratory with international accreditation in the field. This paper presents an application made on bogie frames for the LEMA electric locomotive of 6000 kW.

  15. A Toxocara cati eggs concentration method from cats' faeces, for experimental and diagnostic purposes.

    PubMed

    Cardillo, N; Sommerfelt, I; Fariña, F; Pasqualetti, M; Pérez, M; Ercole, M; Rosa, A; Ribicich, M

    2014-09-01

    Toxocariosis is a zoonotic parasite infection worldwide distributed, now considered a neglected disease associated to poverty. For experimental infection in animals and to develop the diagnosis in humans it is necessary to obtain large number of Toxocara spp. larval eggs. Toxocara cati eggs recovered percentage from faeces of infected cats was determined employing a novel egg concentration method. The McMaster egg counting technique and the concentration method were applied on 20 positive cats' sample faeces obtained from naturally infected cats. The mean percentage of eggs recovered by the concentration method was 24.37% higher than the count obtained by McMaster egg counting technique. The main advantage of this method is that it can be obtained a small final volume with a high number of recovered eggs and a good quality inoculum for experimental and diagnostic purposes. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Damage detection by a FE model updating method using power spectral density: Numerical and experimental investigation

    NASA Astrophysics Data System (ADS)

    Pedram, Masoud; Esfandiari, Akbar; Khedmati, Mohammad Reza

    2017-06-01

    This paper investigates the viability of damage detection using power spectral density (PSD) of structural response both numerically and experimentally. The paper establishes a sensitivity based damage detection method to use PSD. The advantages of PSD as a model updating metric are explained and its challenges are addressed. An approximate frequency response function of damaged model is used to redeem the method for the effect of incomplete measurement. The robust solution of the developed sensitivity equation is achieved through a least-squares error minimization scheme, and the challenging issues are discussed. The ability of the method in localizing and quantifying the damage and its robustness against measurement and modeling errors is investigated by a numerical example. Experimental vibration test data of a laboratory concrete beam with various level of distributed damage is used to probe the method in practical conditions. The results show that PSD of response can be used to detect damages in lower frequency ranges with acceptable accuracy.

  17. Efficient and Minimal Method to Bias Molecular Simulations with Experimental Data.

    PubMed

    White, Andrew D; Voth, Gregory A

    2014-08-12

    A primary goal in molecular simulations is to modify the potential energy of a system so that properties of the simulation match experimental data. This is traditionally done through iterative cycles of simulation and reparameterization. An alternative approach is to bias the potential energy so that the system matches experimental data. This can be done while minimally changing the underlying free energy of the molecular simulation. Current minimal biasing methods require replicas, which can lead to unphysical dynamics and introduces new complexity: the choice of replica number and their properties. Here, we describe a new method, called experiment directed simulation that does not require replicas, converges rapidly, can match many data simultaneously, and minimally modifies the potential. The experiment directed simulation method is demonstrated on model systems and a three-component electrolyte simulation. The theory used to derive the method also provides insight into how changing a molecular force-field impacts the expected value of observables in simulation.

  18. Experimental method for determination of bending and torsional rigidities of advanced composite laminates

    SciTech Connect

    Maeda, Takenori

    1995-11-01

    This paper presents an experimental method for the determination of the bending and torsional rigidities of advanced fiber composite laminates with the aid of laser holographic interferometry. The proposed method consists of a four-point bending test and a resonance test. The bending rigidity ratio (D{sub 12}/D{sub 22}) can be determined from the fringe patterns of the four-point bending test. The bending rigidities (D{sub 11} and D{sub 22}) and the torsional rigidity (D{sub 66}) are calculated from the natural frequencies of cantilever plates of the resonance test. The test specimens are carbon/epoxy cross-ply laminates. The adequacy of the experimental method is confirmed by comparing the measured rigidities with the theoretical values obtained from classical lamination theory (CLT) by using the measured tensile properties. The results show that the present method can be used to evaluate the rigidities of orthotropic laminates with reasonably good accuracy.

  19. Development of an experimental method to determine the axial rigidity of a strut-node joint

    NASA Technical Reports Server (NTRS)

    Brewer, W. V.; Shih, Hui-Ru

    1993-01-01

    The following are presented: the experimental procedure and the results that have been performed to determine the axial rigidity of the strut-node joint; and the method for modifying a simple testing machine to make it capable of performing more accurate tests over a specific load range and able to accept larger test assemblies.

  20. The Use of Techniques of Sensory Evaluation as a Framework for Teaching Experimental Methods.

    ERIC Educational Resources Information Center

    Bennett, R.; Hamilton, M.

    1981-01-01

    Describes sensory assessment techniques and conditions for their satisfactory performance, including how they can provide open-ended exercises and advantages as relatively inexpensive and simple methods of teaching experimentation. Experiments described focus on diffusion of salt into potatoes after being cooked in boiled salted water. (Author/JN)

  1. The Use of Techniques of Sensory Evaluation as a Framework for Teaching Experimental Methods.

    ERIC Educational Resources Information Center

    Bennett, R.; Hamilton, M.

    1981-01-01

    Describes sensory assessment techniques and conditions for their satisfactory performance, including how they can provide open-ended exercises and advantages as relatively inexpensive and simple methods of teaching experimentation. Experiments described focus on diffusion of salt into potatoes after being cooked in boiled salted water. (Author/JN)

  2. Methods of computer processing of experimental data on the intensity of bunches in synchrotrons

    NASA Astrophysics Data System (ADS)

    Zhabitsky, V. M.

    2016-12-01

    Methods of computer processing of experimental data on the intensity of bunches in synchrotrons for the purpose of receiving functional dependences from time during the accelerating cycle for a number of circulating particles and the mean-square length of a bunch are discussed. Examples of such dependences for the beam at the nuclotron (JINR) and PSB (CERN) are presented.

  3. Development of an experimental method to determine the axial rigidity of a strut-node joint

    NASA Technical Reports Server (NTRS)

    Brewer, W. V.; Shih, Hui-Ru

    1993-01-01

    The following are presented: the experimental procedure and the results that have been performed to determine the axial rigidity of the strut-node joint; and the method for modifying a simple testing machine to make it capable of performing more accurate tests over a specific load range and able to accept larger test assemblies.

  4. Sequential Experimentation: Comparing Stochastic Approximation Methods Which Find the "Right" Value of the Independent Variable.

    ERIC Educational Resources Information Center

    Hummel, Thomas J.; Johnston, Charles B.

    This research investigates stochastic approximation procedures of the Robbins-Monro type. Following a brief introduction to sequential experimentation, attention is focused on formal methods for selecting successive values of a single independent variable. Empirical results obtained through computer simulation are used to compare several formal…

  5. Determination of competitive adsorption isotherms applying the nonlinear frequency response method. Part II. Experimental demonstration.

    PubMed

    Ilić, Milica; Petkovska, Menka; Seidel-Morgenstern, Andreas

    2009-08-14

    This paper demonstrates an experimental application of the nonlinear frequency response (FR) method extension to determine adsorption isotherms of binary mixtures. This method, based on the analysis of the response of a chromatographic column subjected to the sinusoidal inlet concentration changes, is shown to be an alternative for isotherm determination. The critical issue related to the successful application of the method is to reach experimentally the low frequency asymptotic behaviour of the corresponding frequency response functions (FRFs). Although, there are different possibilities to perform periodical inlet concentration changes, in this paper only simultaneous changes for both components were considered. The adsorption of phenol and 2-phenylethanol on octadecyl silica was analyzed experimentally using a mixture of methanol and water as a solvent. Parameters of competitive isotherms were also estimated for comparison using the classical perturbation method. Despite certain differences between competitive isotherms estimated with the two methods that were found, the obtained results show the potential of the nonlinear FR method for measuring competitive isotherms.

  6. CFD and Experimental Studies on Wind Turbines in Complex Terrain by Improved Actuator Disk Method

    NASA Astrophysics Data System (ADS)

    Liu, Xin; Yan, Shu; Mu, Yanfei; Chen, Xinming; Shi, Shaoping

    2017-05-01

    In this paper, an onshore wind farm in mountainous area of southwest China was investigated through numerical and experimental methods. An improved actuator disk method, taking rotor data (i.e. blade geometry information, attack angle, blade pitch angle) into account, was carried out to investigate the flow characteristic of the wind farm, especially the wake developing behind the wind turbines. Comparing to the classic AD method and the situ measurements, the improved AD shows better agreements with the measurements. The turbine power was automatically predicted in CFD by blade element method, which agreed well with the measurement results. The study proved that the steady CFD simulation with improved actuator disk method was able to evaluate wind resource well and give good balance between computing efficiency and accuracy, in contrary to much more expensive computation methods such as actuator-line/actuator-surface transient model, or less accurate methods such as linear velocity reduction wake model.

  7. An Improved Experimental Method for Simulating Erosion Processes by Concentrated Channel Flow

    PubMed Central

    Chen, Xiao-Yan; Zhao, Yu; Mo, Bin; Mi, Hong-Xing

    2014-01-01

    Rill erosion is an important process that occurs on hill slopes, including sloped farmland. Laboratory simulations have been vital to understanding rill erosion. Previous experiments obtained sediment yields using rills of various lengths to get the sedimentation process, which disrupted the continuity of the rill erosion process and was time-consuming. In this study, an improved experimental method was used to measure the rill erosion processes by concentrated channel flow. By using this method, a laboratory platform, 12 m long and 3 m wide, was used to construct rills of 0.1 m wide and 12 m long for experiments under five slope gradients (5, 10, 15, 20, and 25 degrees) and three flow rates (2, 4, and 8 L min−1). Sediment laden water was simultaneously sampled along the rill at locations 0.5 m, 1 m, 2 m, 3 m, 4 m, 5 m, 6 m, 7 m, 8 m, 10 m, and 12 m from the water inlet to determine the sediment concentration distribution. The rill erosion process measured by the method used in this study and that by previous experimental methods are approximately the same. The experimental data indicated that sediment concentrations increase with slope gradient and flow rate, which highlights the hydraulic impact on rill erosion. Sediment concentration increased rapidly at the initial section of the rill, and the rate of increase in sediment concentration reduced with the rill length. Overall, both experimental methods are feasible and applicable. However, the method proposed in this study is more efficient and easier to operate. This improved method will be useful in related research. PMID:24949621

  8. An improved experimental method for simulating erosion processes by concentrated channel flow.

    PubMed

    Chen, Xiao-Yan; Zhao, Yu; Mo, Bin; Mi, Hong-Xing

    2014-01-01

    Rill erosion is an important process that occurs on hill slopes, including sloped farmland. Laboratory simulations have been vital to understanding rill erosion. Previous experiments obtained sediment yields using rills of various lengths to get the sedimentation process, which disrupted the continuity of the rill erosion process and was time-consuming. In this study, an improved experimental method was used to measure the rill erosion processes by concentrated channel flow. By using this method, a laboratory platform, 12 m long and 3 m wide, was used to construct rills of 0.1 m wide and 12 m long for experiments under five slope gradients (5, 10, 15, 20, and 25 degrees) and three flow rates (2, 4, and 8 L min(-1)). Sediment laden water was simultaneously sampled along the rill at locations 0.5 m, 1 m, 2 m, 3 m, 4 m, 5 m, 6 m, 7 m, 8 m, 10 m, and 12 m from the water inlet to determine the sediment concentration distribution. The rill erosion process measured by the method used in this study and that by previous experimental methods are approximately the same. The experimental data indicated that sediment concentrations increase with slope gradient and flow rate, which highlights the hydraulic impact on rill erosion. Sediment concentration increased rapidly at the initial section of the rill, and the rate of increase in sediment concentration reduced with the rill length. Overall, both experimental methods are feasible and applicable. However, the method proposed in this study is more efficient and easier to operate. This improved method will be useful in related research.

  9. Experimental and statistical approaches in method cross-validation to support pharmacokinetic decisions.

    PubMed

    Thway, Theingi M; Ma, Mark; Lee, Jean; Sloey, Bethlyn; Yu, Steven; Wang, Yow-Ming C; Desilva, Binodh; Graves, Tom

    2009-04-05

    A case study of experimental and statistical approaches for cross-validating and examining the equivalence of two ligand binding assay (LBA) methods that were employed in pharmacokinetic (PK) studies is presented. The impact of changes in methodology based on the intended use of the methods was assessed. The cross-validation processes included an experimental plan, sample size selection, and statistical analysis with a predefined criterion of method equivalence. The two methods were deemed equivalent if the ratio of mean concentration fell within the 90% confidence interval (0.80-1.25). Statistical consideration of method imprecision was used to choose the number of incurred samples (collected from study animals) and conformance samples (spiked controls) for equivalence tests. The difference of log-transformed mean concentration and the 90% confidence interval for two methods were computed using analysis of variance. The mean concentration ratios of the two methods for the incurred and spiked conformance samples were 1.63 and 1.57, respectively. The 90% confidence limit was 1.55-1.72 for the incurred samples and 1.54-1.60 for the spiked conformance samples; therefore, the 90% confidence interval was not contained within the (0.80-1.25) equivalence interval. When the PK parameters of two studies using each of these two methods were compared, we determined that the therapeutic exposure, AUC((0-168)) and C(max), from Study A/Method 1 was approximately twice that of Study B/Method 2. We concluded that the two methods were not statistically equivalent and that the magnitude of the difference was reflected in the PK parameters in the studies using each method. This paper demonstrates the need for method cross-validation whenever there is a switch in bioanalytical methods, statistical approaches in designing the cross-validation experiments and assessing results, or interpretation of the impact of PK data.

  10. Experimental Method for Characterizing Electrical Steel Sheets in the Normal Direction

    PubMed Central

    Hihat, Nabil; Lecointe, Jean Philippe; Duchesne, Stephane; Napieralska, Ewa; Belgrand, Thierry

    2010-01-01

    This paper proposes an experimental method to characterise magnetic laminations in the direction normal to the sheet plane. The principle, which is based on a static excitation to avoid planar eddy currents, is explained and specific test benches are proposed. Measurements of the flux density are made with a sensor moving in and out of an air-gap. A simple analytical model is derived in order to determine the permeability in the normal direction. The experimental results for grain oriented steel sheets are presented and a comparison is provided with values obtained from literature. PMID:22163394

  11. Experimental methods for quantifying the activity of platinum electrocatalysts for the oxygen reduction reaction.

    PubMed

    Garsany, Yannick; Baturina, Olga A; Swider-Lyons, Karen E; Kocha, Shyam S

    2010-08-01

    A tutorial is provided for methods to accurately and reproducibly determine the activity of Pt-based electrocatalysts for the oxygen reduction reaction in proton exchange membrane fuel cells and other applications. The impact of various experimental parameters on electrocatalyst activity is demonstrated, and explicit experimental procedures and measurement protocols are given for comparison of electrocatalyst activity to fuel cell standards. (To listen to a podcast about this article, please go to the Analytical Chemistry multimedia page at pubs.acs.org/page/ancham/audio/index.html.).

  12. Comparative study of sound absorption coefficient determination using FEM method and experimental tests on Kundt's tube

    NASA Astrophysics Data System (ADS)

    Deaconu, Marius; Toma, Adina Cristina; Dragasanu, Luminita Ioana; Mihai, Dragos

    2017-06-01

    Sound absorption coefficient is a commonly used parameter to characterize the acoustic properties of sound absorbing materials that plays an important role in noise attenuation. For this study a specific material has been chosen in order to be evaluated experimentally and compared with the simulated results. Both simulation and experimental assessments used to estimate the sound absorption coefficient are based on transfer function method in accordance with standard SR EN JSO 10354-2. Results are obtained for 15, 30, 45 mm material sample thickness in order to assess the relationship between absorption coefficient, thickness and frequency response. Comparative analysis is performed to determine differences given by the two approaches.

  13. Bidirectional Connected Control Method Applied to an Experimental Structural Model Split into Four Substructures

    NASA Astrophysics Data System (ADS)

    Watanabe, T.; Seto, K.; Toyoda, H.; Takano, T.

    2016-09-01

    Connected Control Method (CCM) is a well-known mechanism in the field of civil structural vibration control that utilizes mutual reaction forces between plural buildings connected by dampers as damping force. However, the fact that CCM requires at least two buildings to obtain reaction force prevents CCM from further development. In this paper, a novel idea to apply CCM onto a single building by splitting the building into four substructures is presented. An experimental model structure split into four is built and CCM is applied by using four magnetic dampers. Experimental analysis is carried out and basic performance and effectiveness of the presented idea is confirmed.

  14. Disorder Prediction Methods, Their Applicability to Different Protein Targets and Their Usefulness for Guiding Experimental Studies

    PubMed Central

    Atkins, Jennifer D.; Boateng, Samuel Y.; Sorensen, Thomas; McGuffin, Liam J.

    2015-01-01

    The role and function of a given protein is dependent on its structure. In recent years, however, numerous studies have highlighted the importance of unstructured, or disordered regions in governing a protein’s function. Disordered proteins have been found to play important roles in pivotal cellular functions, such as DNA binding and signalling cascades. Studying proteins with extended disordered regions is often problematic as they can be challenging to express, purify and crystallise. This means that interpretable experimental data on protein disorder is hard to generate. As a result, predictive computational tools have been developed with the aim of predicting the level and location of disorder within a protein. Currently, over 60 prediction servers exist, utilizing different methods for classifying disorder and different training sets. Here we review several good performing, publicly available prediction methods, comparing their application and discussing how disorder prediction servers can be used to aid the experimental solution of protein structure. The use of disorder prediction methods allows us to adopt a more targeted approach to experimental studies by accurately identifying the boundaries of ordered protein domains so that they may be investigated separately, thereby increasing the likelihood of their successful experimental solution. PMID:26287166

  15. Synchronizing chaos in an experimental chaotic pendulum using methods from linear control theory.

    PubMed

    Kaart, S; Schouten, J C; van den Bleek, C M

    1999-05-01

    Linear feedback control, specifically model predictive control (MPC), was used successfully to synchronize an experimental chaotic pendulum both on unstable periodic and aperiodic orbits. MPC enables tuning of the controller to give an optimal controller performance. That is, both the fluctuations around the target trajectory and the necessary control actions are minimized using a least-squares solution of the linearized problem. It is thus shown that linear control methods can be applied to experimental chaotic systems, as long as an adequate model is available that can be linearized along the desired trajectory. This model is used as an observer, i.e., it is synchronized with the experimental pendulum to estimate the state of the experimental pendulum. In contrast with other chaos control procedures like the map-based Ott, Grebogi, and York method [Phys. Rev. Lett. 64, 1196 (1990)], the continuous type feedback control proposed by Pyragas [Phys. Lett. A 170, 421 (1992)], or the feedback control method recently proposed by Brown and Rulkov [Chaos 7 (3), 395 (1997)], the procedure outlined in this paper automatically results in a choice for the feedback gains that gives optimum performance, i.e., minimum fluctuations around the desired trajectory using minimum control actions.

  16. Synchronizing chaos in an experimental chaotic pendulum using methods from linear control theory

    NASA Astrophysics Data System (ADS)

    Kaart, Sander; Schouten, Jaap C.; van den Bleek, Cor M.

    1999-05-01

    Linear feedback control, specifically model predictive control (MPC), was used successfully to synchronize an experimental chaotic pendulum both on unstable periodic and aperiodic orbits. MPC enables tuning of the controller to give an optimal controller performance. That is, both the fluctuations around the target trajectory and the necessary control actions are minimized using a least-squares solution of the linearized problem. It is thus shown that linear control methods can be applied to experimental chaotic systems, as long as an adequate model is available that can be linearized along the desired trajectory. This model is used as an observer, i.e., it is synchronized with the experimental pendulum to estimate the state of the experimental pendulum. In contrast with other chaos control procedures like the map-based Ott, Grebogi, and York method [Phys. Rev. Lett. 64, 1196 (1990)], the continuous type feedback control proposed by Pyragas [Phys. Lett. A 170, 421 (1992)], or the feedback control method recently proposed by Brown and Rulkov [Chaos 7 (3), 395 (1997)], the procedure outlined in this paper automatically results in a choice for the feedback gains that gives optimum performance, i.e., minimum fluctuations around the desired trajectory using minimum control actions.

  17. An experimental method of modeling ;Line-Type; and ;Area-Type; connections

    NASA Astrophysics Data System (ADS)

    Wang, Mian; Zheng, Gangtie

    2017-07-01

    A method for experimentally modeling complex connections, such as ;Line-Type; connection (LTC) and ;Area-Type; connection (ATC), is proposed in this paper. Unlike traditional methods, instead of treating the junction forces as presumed approximate functions, a new strategy proposed in the present paper is to estimate them from experimentally measured accelerations. Along with them, the junction motion information is also estimated from the measured data. Based on this estimated information, the connection's model is built. In this way, two potential disadvantages of traditional methods in modeling complex connections, i.e. the difficulty in finding appropriate functions for complex connections and the computation burden in identifying too many parameters through optimization process, can be avoided. In the proposed method, the LTC is modeled as a series of independent junction node pairs, and the ATC is modeled as a combination of a presumed Virtual Structure and a series of independent Virtual Node Pairs. Numerical and experimental results with the constructed example have verified the effectiveness of the proposed method in modeling both LTC and ATC.

  18. A Novel Method for Curvefitting the Stretched Exponential Function to Experimental Data.

    PubMed

    June, Ronald K; Cunningham, John P; Fyhrie, David P

    2013-12-01

    The stretched exponential function has many applications in modeling numerous types of experimental relaxation data. However, problems arise when using standard algorithms to fit this function: we have observed that different initializations result in distinct fitted parameters. To avoid this problem, we developed a novel algorithm for fitting the stretched exponential model to relaxation data. This method is advantageous both because it requires only a single adjustable parameter and because it does not require initialization in the solution space. We tested this method on simulated data and experimental stress-relaxation data from bone and cartilage and found favorable results compared to a commonly-used Quasi-Newton method. For the simulated data, strong correlations were found between the simulated and fitted parameters suggesting that this method can accurately determine stretched exponential parameters. When this method was tested on experimental data, high quality fits were observed for both bone and cartilage stress-relaxation data that were significantly better than those determined with the Quasi-Newton algorithm.

  19. Methods for determining the internal thrust of scramjet engine modules from experimental data

    NASA Technical Reports Server (NTRS)

    Voland, Randall T.

    1990-01-01

    Methods for calculating zero-fuel internal drag of scramjet engine modules from experimental measurements are presented. These methods include two control-volume approaches, and a pressure and skin-friction integration. The three calculation techniques are applied to experimental data taken during tests of a version of the NASA parametric scramjet. The methods agree to within seven percent of the mean value of zero-fuel internal drag even though several simplifying assumptions are made in the analysis. The mean zero-fuel internal drag coefficient for this particular engine is calculated to be 0.150. The zero-fuel internal drag coefficient when combined with the change in engine axial force with and without fuel defines the internal thrust of an engine.

  20. Methods for determining the internal thrust of scramjet engine modules from experimental data

    NASA Technical Reports Server (NTRS)

    Voland, Randall T.

    1990-01-01

    Methods for calculating zero-fuel internal drag of scramjet engine modules from experimental measurements are presented. These methods include two control-volume approaches, and a pressure and skin-friction integration. The three calculation techniques are applied to experimental data taken during tests of a version of the NASA parametric scramjet. The methods agree to within seven percent of the mean value of zero-fuel internal drag even though several simplifying assumptions are made in the analysis. The mean zero-fuel internal drag coefficient for this particular engine is calculated to be 0.150. The zero-fuel internal drag coefficient when combined with the change in engine axial force with and without fuel defines the internal thrust of an engine.

  1. Clinical experimentation with aerosol antibiotics: current and future methods of administration.

    PubMed

    Zarogoulidis, Paul; Kioumis, Ioannis; Porpodis, Konstantinos; Spyratos, Dionysios; Tsakiridis, Kosmas; Huang, Haidong; Li, Qiang; Turner, J Francis; Browning, Robert; Hohenforst-Schmidt, Wolfgang; Zarogoulidis, Konstantinos

    2013-01-01

    Currently almost all antibiotics are administered by the intravenous route. Since several systems and situations require more efficient methods of administration, investigation and experimentation in drug design has produced local treatment modalities. Administration of antibiotics in aerosol form is one of the treatment methods of increasing interest. As the field of drug nanotechnology grows, new molecules have been produced and combined with aerosol production systems. In the current review, we discuss the efficiency of aerosol antibiotic studies along with aerosol production systems. The different parts of the aerosol antibiotic methodology are presented. Additionally, information regarding the drug molecules used is presented and future applications of this method are discussed.

  2. Clinical experimentation with aerosol antibiotics: current and future methods of administration

    PubMed Central

    Zarogoulidis, Paul; Kioumis, Ioannis; Porpodis, Konstantinos; Spyratos, Dionysios; Tsakiridis, Kosmas; Huang, Haidong; Li, Qiang; Turner, J Francis; Browning, Robert; Hohenforst-Schmidt, Wolfgang; Zarogoulidis, Konstantinos

    2013-01-01

    Currently almost all antibiotics are administered by the intravenous route. Since several systems and situations require more efficient methods of administration, investigation and experimentation in drug design has produced local treatment modalities. Administration of antibiotics in aerosol form is one of the treatment methods of increasing interest. As the field of drug nanotechnology grows, new molecules have been produced and combined with aerosol production systems. In the current review, we discuss the efficiency of aerosol antibiotic studies along with aerosol production systems. The different parts of the aerosol antibiotic methodology are presented. Additionally, information regarding the drug molecules used is presented and future applications of this method are discussed. PMID:24115836

  3. Experimental comparison and validation of hot-ball method with guarded hot plate method on polyurethane foams

    NASA Astrophysics Data System (ADS)

    Hudec, Ján; Glorieux, Christ; Dieška, Peter; Kubičár, Ľudovít

    2016-07-01

    The Hot-ball method is an innovative transient method for measuring thermophysical properties. The principle is based on heating of a small ball, incorporated in measured medium, by constant heating power and simultaneous measuring of the ball's temperature response since the heating was initiated. The shape of the temperature response depends on thermophysical properties of the medium, where the sensor is placed. This method is patented by Institute of Physics, SAS, where the method and sensors based on this method are being developed. At the beginning of the development of sensors for this method we were oriented on monitoring applications, where relative precision is much more important than accuracy. Meanwhile, the quality of sensors was improved good enough to be used for a new application - absolute measuring of thermophysical parameters of low thermally conductive materials. This paper describes experimental verification and validation of measurement by hot-ball method. Thanks to cooperation with Laboratory of Soft Matter and Biophysics of Catholic University of Leuven in Belgium, established Guarded Hot Plate method was used as a reference. Details about measuring setups, description of the experiments and results of the comparison are presented.

  4. Experimental Validation of Normalized Uniform Load Surface Curvature Method for Damage Localization

    PubMed Central

    Jung, Ho-Yeon; Sung, Seung-Hoon; Jung, Hyung-Jo

    2015-01-01

    In this study, we experimentally validated the normalized uniform load surface (NULS) curvature method, which has been developed recently to assess damage localization in beam-type structures. The normalization technique allows for the accurate assessment of damage localization with greater sensitivity irrespective of the damage location. In this study, damage to a simply supported beam was numerically and experimentally investigated on the basis of the changes in the NULS curvatures, which were estimated from the modal flexibility matrices obtained from the acceleration responses under an ambient excitation. Two damage scenarios were considered for the single damage case as well as the multiple damages case by reducing the bending stiffness (EI) of the affected element(s). Numerical simulations were performed using MATLAB as a preliminary step. During the validation experiments, a series of tests were performed. It was found that the damage locations could be identified successfully without any false-positive or false-negative detections using the proposed method. For comparison, the damage detection performances were compared with those of two other well-known methods based on the modal flexibility matrix, namely, the uniform load surface (ULS) method and the ULS curvature method. It was confirmed that the proposed method is more effective for investigating the damage locations of simply supported beams than the two conventional methods in terms of sensitivity to damage under measurement noise. PMID:26501286

  5. Experimental validation of normalized uniform load surface curvature method for damage localization.

    PubMed

    Jung, Ho-Yeon; Sung, Seung-Hoon; Jung, Hyung-Jo

    2015-10-16

    In this study, we experimentally validated the normalized uniform load surface (NULS) curvature method, which has been developed recently to assess damage localization in beam-type structures. The normalization technique allows for the accurate assessment of damage localization with greater sensitivity irrespective of the damage location. In this study, damage to a simply supported beam was numerically and experimentally investigated on the basis of the changes in the NULS curvatures, which were estimated from the modal flexibility matrices obtained from the acceleration responses under an ambient excitation. Two damage scenarios were considered for the single damage case as well as the multiple damages case by reducing the bending stiffness (EI) of the affected element(s). Numerical simulations were performed using MATLAB as a preliminary step. During the validation experiments, a series of tests were performed. It was found that the damage locations could be identified successfully without any false-positive or false-negative detections using the proposed method. For comparison, the damage detection performances were compared with those of two other well-known methods based on the modal flexibility matrix, namely, the uniform load surface (ULS) method and the ULS curvature method. It was confirmed that the proposed method is more effective for investigating the damage locations of simply supported beams than the two conventional methods in terms of sensitivity to damage under measurement noise.

  6. Videotaped Feedback Method to Enhance Learning in Preclinical Operative Dentistry: An Experimental Study.

    PubMed

    Shah, Dipali Yogesh; Dadpe, Ashwini Manish; Kalra, Dheeraj Deepak; Garcha, Vikram P

    2015-12-01

    The aim of this study was to investigate if a videotaped feedback method enhanced teaching and learning outcomes in a preclinical operative laboratory setting for novice learners. In 2013, 60 dental students at a dental school in India were randomly assigned to two groups: control (n=30) and experimental (n=30). The control group prepared a Class II tooth preparation for amalgam after receiving a video demonstration of the exercise. The experimental group received the same video demonstration as the control group, but they also participated in a discussion and analysis of the control groups' videotaped performance and then performed the same exercise. The self-evaluation scores (SS) and examiner evaluation scores (ES) of the two groups were compared using the unpaired t-test. The experimental group also used a five-point Likert scale to rate each item on the feedback form. The means of SS (13.65±2.43) and ES (14.75±1.97) of the experimental group were statistically higher than the means of SS (11.55±2.09) and ES (11.60±1.82) of the control group. Most students in the experimental group perceived that this technique enhanced their learning experience. Within the limits of this study, the videotaped feedback using both ideal and non-ideal examples enhanced the students' performance.

  7. Methods for obtaining and reducing experimental droplet impingement data on arbitrary bodies

    NASA Technical Reports Server (NTRS)

    Papadakis, Michael; Elangovan, R.; Freund, George A., Jr.; Breer, Marlin D.

    1991-01-01

    Experimental water droplet impingement data are used to validate particle trajectory computer codes used in the analysis and certification of aircraft de-icing/anti-icing systems. Water droplet impingement characteristics of aerodynamic surfaces are usually obtained from wind-tunnel dye tracer experiments. This paper presents a dye tracer method for measuring water droplet impingement characteristics on arbitrary geometries and a new data reduction method, based on laser reflectance measurements, for extracting impingement data. Extraction of impingement data has been a very time-consuming process in the past. The new data reduction method developed is at least an order of magnitude more efficient than the method previously used. The accuracy of the method is discussed and results obtained are presented.

  8. Methods for obtaining and reducing experimental droplet impingement data on arbitrary bodies

    NASA Astrophysics Data System (ADS)

    Papadakis, Michael; Elangovan, R.; Freund, George A., Jr.; Breer, Marlin D.

    1991-05-01

    Experimental water droplet impingement data are used to validate particle trajectory computer codes used in the analysis and certification of aircraft de-icing/anti-icing systems. Water droplet impingement characteristics of aerodynamic surfaces are usually obtained from wind-tunnel dye tracer experiments. This paper presents a dye tracer method for measuring water droplet impingement characteristics on arbitrary geometries and a new data reduction method, based on laser reflectance measurements, for extracting impingement data. Extraction of impingement data has been a very time-consuming process in the past. The new data reduction method developed is at least an order of magnitude more efficient than the method previously used. The accuracy of the method is discussed and results obtained are presented.

  9. Methods for obtaining and reducing experimental droplet impingement data on arbitrary bodies

    NASA Technical Reports Server (NTRS)

    Papadakis, Michael; Elangovan, R.; Freund, George A., Jr.; Breer, Marlin D.

    1991-01-01

    Experimental water droplet impingement data are used to validate particle trajectory computer codes used in the analysis and certification of aircraft de-icing/anti-icing systems. Water droplet impingement characteristics of aerodynamic surfaces are usually obtained from wind-tunnel dye tracer experiments. This paper presents a dye tracer method for measuring water droplet impingement characteristics on arbitrary geometries and a new data reduction method, based on laser reflectance measurements, for extracting impingement data. Extraction of impingement data has been a very time-consuming process in the past. The new data reduction method developed is at least an order of magnitude more efficient than the method previously used. The accuracy of the method is discussed and results obtained are presented.

  10. Experimental demonstration of scanning phase retrieval by a noniterative method with a Gaussian-amplitude beam

    NASA Astrophysics Data System (ADS)

    Nakajima, Nobuharu; Yoshino, Masayuki

    2017-01-01

    We present a proof-of-principle experiment of an analytic (noniterative) phase-retrieval method for coherent imaging systems under scanning illumination of a probe beam. This method allows to reconstruct the amplitude and phase distribution of a semi-transparent object over a wide area from intensities measured at three points in the Fourier plane of the object under scanning illumination of a known Gaussian-amplitude beam in the object plane. The present measurement system is very simple in contrast to ones of interferometric techniques, and also the speed of the calculation of phase retrieval in this method is faster than that in iterative algorithms since this method is based on an analytic solution to the phase retrieval. The effectiveness of this method is shown in experimental examples of the object reconstructions of a converging lens and a plastic plate for scratch standards.

  11. An Experimental Comparison of Two Methods on Photosynthesis Driving Soil Respiration: Girdling and Defoliation.

    PubMed

    Jing, Yanli; Guan, Dexin; Wu, Jiabing; Wang, Anzhi; Jin, Changjie; Yuan, Fenghui

    2015-01-01

    Previous studies with different experimental methods have demonstrated that photosynthesis significantly influences soil respiration (RS). To compare the experimental results of different methods, RS after girdling and defoliation was measured in five-year-old seedlings of Fraxinus mandshurica from June to September. Girdling and defoliation significantly reduced RS by 33% and 25% within 4 days, and 40% and 32% within the entire treatment period, respectively. The differential response of RS to girdling and defoliation was a result of the over-compensation for RS after girdling and redistribution of stored carbon after defoliation. No significant effect on RS was observed between girdling and defoliation treatment, while the soluble sugar content in fine roots was higher in defoliation than in girdling treatment, indicating that defoliation had less compensation effect for RS after interrupting photosynthates supply. We confirm the close coupling of RS with photosynthesis and recommend defoliation for further studies to estimate the effect of photosynthesis on RS.

  12. Numerical and experimental validation of a particle Galerkin method for metal grinding simulation

    NASA Astrophysics Data System (ADS)

    Wu, C. T.; Bui, Tinh Quoc; Wu, Youcai; Luo, Tzui-Liang; Wang, Morris; Liao, Chien-Chih; Chen, Pei-Yin; Lai, Yu-Sheng

    2017-08-01

    In this paper, a numerical approach with an experimental validation is introduced for modelling high-speed metal grinding processes in 6061-T6 aluminum alloys. The derivation of the present numerical method starts with an establishment of a stabilized particle Galerkin approximation. A non-residual penalty term from strain smoothing is introduced as a means of stabilizing the particle Galerkin method. Additionally, second-order strain gradients are introduced to the penalized functional for the regularization of damage-induced strain localization problem. To handle the severe deformation in metal grinding simulation, an adaptive anisotropic Lagrangian kernel is employed. Finally, the formulation incorporates a bond-based failure criterion to bypass the prospective spurious damage growth issues in material failure and cutting debris simulation. A three-dimensional metal grinding problem is analyzed and compared with the experimental results to demonstrate the effectiveness and accuracy of the proposed numerical approach.

  13. An Experimental Comparison of Two Methods on Photosynthesis Driving Soil Respiration: Girdling and Defoliation

    PubMed Central

    Jing, Yanli; Guan, Dexin; Wu, Jiabing; Wang, Anzhi; Jin, Changjie; Yuan, Fenghui

    2015-01-01

    Previous studies with different experimental methods have demonstrated that photosynthesis significantly influences soil respiration (RS). To compare the experimental results of different methods, RS after girdling and defoliation was measured in five-year-old seedlings of Fraxinus mandshurica from June to September. Girdling and defoliation significantly reduced RS by 33% and 25% within 4 days, and 40% and 32% within the entire treatment period, respectively. The differential response of RS to girdling and defoliation was a result of the over-compensation for RS after girdling and redistribution of stored carbon after defoliation. No significant effect on RS was observed between girdling and defoliation treatment, while the soluble sugar content in fine roots was higher in defoliation than in girdling treatment, indicating that defoliation had less compensation effect for RS after interrupting photosynthates supply. We confirm the close coupling of RS with photosynthesis and recommend defoliation for further studies to estimate the effect of photosynthesis on RS. PMID:26177498

  14. DETECTORS AND EXPERIMENTAL METHODS: Decay vertex reconstruction and 3-dimensional lifetime determination at BESIII

    NASA Astrophysics Data System (ADS)

    Xu, Min; He, Kang-Lin; Zhang, Zi-Ping; Wang, Yi-Fang; Bian, Jian-Ming; Cao, Guo-Fu; Cao, Xue-Xiang; Chen, Shen-Jian; Deng, Zi-Yan; Fu, Cheng-Dong; Gao, Yuan-Ning; Han, Lei; Han, Shao-Qing; He, Miao; Hu, Ji-Feng; Hu, Xiao-Wei; Huang, Bin; Huang, Xing-Tao; Jia, Lu-Kui; Ji, Xiao-Bin; Li, Hai-Bo; Li, Wei-Dong; Liang, Yu-Tie; Liu, Chun-Xiu; Liu, Huai-Min; Liu, Ying; Liu, Yong; Luo, Tao; Lü, Qi-Wen; Ma, Qiu-Mei; Ma, Xiang; Mao, Ya-Jun; Mao, Ze-Pu; Mo, Xiao-Hu; Ning, Fei-Peng; Ping, Rong-Gang; Qiu, Jin-Fa; Song, Wen-Bo; Sun, Sheng-Sen; Sun, Xiao-Dong; Sun, Yong-Zhao; Tian, Hao-Lai; Wang, Ji-Ke; Wang, Liang-Liang; Wen, Shuo-Pin; Wu, Ling-Hui; Wu, Zhi; Xie, Yu-Guang; Yan, Jie; Yan, Liang; Yao, Jian; Yuan, Chang-Zheng; Yuan, Ye; Zhang, Chang-Chun; Zhang, Jian-Yong; Zhang, Lei; Zhang, Xue-Yao; Zhang, Yao; Zheng, Yang-Heng; Zhu, Yong-Sheng; Zou, Jia-Heng

    2009-06-01

    This paper focuses mainly on the vertex reconstruction of resonance particles with a relatively long lifetime such as K0S, Λ, as well as on lifetime measurements using a 3-dimensional fit. The kinematic constraints between the production and decay vertices and the decay vertex fitting algorithm based on the least squares method are both presented. Reconstruction efficiencies including experimental resolutions are discussed. The results and systematic errors are calculated based on a Monte Carlo simulation.

  15. Experimental validation of finite element and boundary element methods for predicting structural vibration and radiated noise

    NASA Technical Reports Server (NTRS)

    Seybert, A. F.; Wu, T. W.; Wu, X. F.

    1994-01-01

    This research report is presented in three parts. In the first part, acoustical analyses were performed on modes of vibration of the housing of a transmission of a gear test rig developed by NASA. The modes of vibration of the transmission housing were measured using experimental modal analysis. The boundary element method (BEM) was used to calculate the sound pressure and sound intensity on the surface of the housing and the radiation efficiency of each mode. The radiation efficiency of each of the transmission housing modes was then compared to theoretical results for a finite baffled plate. In the second part, analytical and experimental validation of methods to predict structural vibration and radiated noise are presented. A rectangular box excited by a mechanical shaker was used as a vibrating structure. Combined finite element method (FEM) and boundary element method (BEM) models of the apparatus were used to predict the noise level radiated from the box. The FEM was used to predict the vibration, while the BEM was used to predict the sound intensity and total radiated sound power using surface vibration as the input data. Vibration predicted by the FEM model was validated by experimental modal analysis; noise predicted by the BEM was validated by measurements of sound intensity. Three types of results are presented for the total radiated sound power: sound power predicted by the BEM model using vibration data measured on the surface of the box; sound power predicted by the FEM/BEM model; and sound power measured by an acoustic intensity scan. In the third part, the structure used in part two was modified. A rib was attached to the top plate of the structure. The FEM and BEM were then used to predict structural vibration and radiated noise respectively. The predicted vibration and radiated noise were then validated through experimentation.

  16. Experimental Validation of Finite Element and Boundary Element Methods for Predicting Structural Vibration and Radiated Noise

    NASA Astrophysics Data System (ADS)

    Wu, Xuefeng

    1992-01-01

    The research presented in this dissertation is reported in three parts. In the first part, acoustical analyses were performed on modes of vibration of the housing of a transmission of a gear test rig developed by NASA. The modes of vibration of the transmission housing were measured using experimental modal analysis. The boundary element method (BEM) was used to calculate the sound pressure and sound intensity on the surface of the housing, and the radiation efficiency of each mode. The radiation efficiency of the transmission housing modes was then compared to theoretical results for finite, baffled plate. In the second part, analytical and experimental validation of methods to predict structural vibration and radiated noise are presented. A rectangular box excited by a mechanical shaker was used as a vibrating structure. Combined finite element method (FEM) and boundary element method (BEM) models of the apparatus were used to predict the noise level expected to be radiated from the box. The FEM was used to predict the vibration, while the BEM was used to predict the sound intensity and total radiated sound power using surface vibration as the input data. Vibration predicted by the FEM model was validated by experimental modal analysis, noise predicted by the BEM was validated by measurements of sound intensity. Three types of results are presented for the total radiated sound power: (1) sound power predicted by the BEM model using vibration data measured on the surface of the box; (2) sound power predicted by the FEM/BEM model; and (3) sound power measured by an acoustic intensity scan. In the third part, the structure used in part two was modified. A rib was attached to the top plate of the structure. The FEM and BEM were then used to predict structural vibration and radiated noise respectively. The predicted vibration and radiated noise were then validated through experimentation.

  17. Experimental verification of color flow imaging based on wideband Doppler method.

    PubMed

    Tanaka, Naohiko

    2014-01-01

    The purpose of this study is to eliminate the aliasing in color flow imaging. The wideband Doppler method is applied to generate a color flow image, and the validity of the method is experimentally confirmed. The single beam experiment is carried out to confirm the velocity estimation based on the wideband Doppler method. The echo data for the conventional pulsed Doppler method and the wideband Doppler method are obtained using a flow model, and the estimated velocity for each method is compared. The color flow images for each method are also generated using several types of flow model. The generated images are compared, and the characteristics of the imaging based on the wideband Doppler method are discussed. The high velocity beyond the Nyquist limit is successfully estimated by the wideband Doppler method, and the availability in low velocity estimation is also confirmed. The aliasing in color flow images is eliminated, and the generated images show the significance of the elimination of the aliasing in the flow imaging. The aliasing in color flow imaging can be eliminated by the wideband Doppler method. This technique is useful for the exact understanding of blood flow dynamics.

  18. Refined method for predicting electrochemical windows of ionic liquids and experimental validation studies.

    PubMed

    Zhang, Yong; Shi, Chaojun; Brennecke, Joan F; Maginn, Edward J

    2014-06-12

    A combined classical molecular dynamics (MD) and ab initio MD (AIMD) method was developed for the calculation of electrochemical windows (ECWs) of ionic liquids. In the method, the liquid phase of ionic liquid is explicitly sampled using classical MD. The electrochemical window, estimated by the energy difference between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), is calculated at the density functional theory (DFT) level based on snapshots obtained from classical MD trajectories. The snapshots were relaxed using AIMD and quenched to their local energy minima, which assures that the HOMO/LUMO calculations are based on stable configurations on the same potential energy surface. The new procedure was applied to a group of ionic liquids for which the ECWs were also experimentally measured in a self-consistent manner. It was found that the predicted ECWs not only agree with the experimental trend very well but also the values are quantitatively accurate. The proposed method provides an efficient way to compare ECWs of ionic liquids in the same context, which has been difficult in experiments or simulation due to the fact that ECW values sensitively depend on experimental setup and conditions.

  19. Quantifying the Performance of P-Type Transparent Conducting Oxides by Experimental Methods.

    PubMed

    Fleischer, Karsten; Norton, Emma; Mullarkey, Daragh; Caffrey, David; Shvets, Igor V

    2017-09-01

    Screening for potential new materials with experimental and theoretical methods has led to the discovery of many promising candidate materials for p-type transparent conducting oxides. It is difficult to reliably assess a good p-type transparent conducting oxide (TCO) from limited information available at an early experimental stage. In this paper we discuss the influence of sample thickness on simple transmission measurements and how the sample thickness can skew the commonly used figure of merit of TCOs and their estimated band gap. We discuss this using copper-deficient CuCrO 2 as an example, as it was already shown to be a good p-type TCO grown at low temperatures. We outline a modified figure of merit reducing thickness-dependent errors, as well as how modern ab initio screening methods can be used to augment experimental methods to assess new materials for potential applications as p-type TCOs, p-channel transparent thin film transistors, and selective contacts in solar cells.

  20. Experimental study to explore the 8Be-induced nuclear reaction via the Trojan horse method

    NASA Astrophysics Data System (ADS)

    Wen, Qun-Gang; Li, Cheng-Bo; Zhou, Shu-Hua; Irgaziev, Bakhadir; Fu, Yuan-Yong; Spitaleri, Claudio; La Cognata, Marco; Zhou, Jing; Meng, Qiu-Ying; Lamia, Livio; Lattuada, Marcello

    2016-03-01

    To explore a possible indirect method for 8Be induced astrophysical reactions, the 8Be=(8Be+n ) cluster structure has been studied via the Trojan horse method. For the first time a 8Be nucleus having an ultrashort lifetime is studied by the Trojan horse method and a 9Be nucleus in the ground state is used for this purpose. The 9Be nucleus is assumed to have a (8Be+n ) cluster structure and used as a Trojan horse nucleus. The 8Be nucleus acts as a participant, while the neutron is a spectator to the virtual 8Be+d →α +6Li reaction via the 3-body reaction 8Be+d →α +6Li+n . The experimental neutron momentum distribution inside 9Be has been reconstructed. The agreement between the experimental momentum distribution and the theoretical one indicates that a (8Be+n ) cluster structure inside 9Be is very likely. Therefore, the experimental study of 8Be induced reactions, for example, the measurement of the 8Be+α →12C reaction proceeding through the Hoyle state, is possible.

  1. Comparative study of experimental and theoretical analysis of EXAFS data of copper complexes using FT method

    NASA Astrophysics Data System (ADS)

    Mishra, A.; Mishra, S.; Kekre, P.; Choudhary, Pankaj

    2014-09-01

    The X-ray absorption spectra at the K-edge for a series of copper mixed ligand, having hydroxypyridine as one of the ligands, have been investigated in the laboratory X-ray spectroscopic set-up. In the series only X-ray absorption near edge structure (XANES) parameters and bond length using modified Lytle, Levy's and LSS methods were calculated. In the present study the bond lengths are calculated by Fourier Transform method theoretically using IFEFFIT software and compared with experimental results.

  2. Control rod heterogeneity effects in liquid-metal fast breeder reactors: Method developments and experimental validation

    SciTech Connect

    Carta, M.; Granget, G.; Palmiotti, G.; Salvatores, M.; Soule, R.

    1988-11-01

    The control rod worth assessment in a large liquid-metal fast breeder reactor is strongly dependent on the actual arrangement of the absorber pins inside the control rod subassemblies. The so-called heterogeneity effects (i.e., the effects on the rod reactivity of the actual rod internal geometry versus homogenization of the absorber atoms over all the subassembly volume) have been evaluated, using explicit and variational methods to derive appropriate cross sections. An experimental program performed at the MASURCA facility has been used to validate these methods.

  3. Experimental stem cell therapies on burn wound: do source, dose, timing and method matter?

    PubMed

    Ozturk, Sinan; Karagoz, Huseyin

    2015-09-01

    Stem cell therapy has been introduced as a new and promising modality of wound covering in recent decade. It has been used for improvement of burn wound, post burn scar and saving stasis zone of burn with good results. However, there have been some differences between the various experimental burn wound trials in stem cell source, therapeutic dose, delivery method and timing of stem cell delivery. In our study, we aimed to review stem cell biology and investigate discrepancies in animal trials of use of stem cells in burn wound account for the variation in, stem cell source, therapeutic dose, delivery method and timing of stem cell delivery.

  4. A hybrid numerical-experimental method for determination of dynamic fracture properties of material

    NASA Astrophysics Data System (ADS)

    Mihradi, S.; Putra, I. S.; Dirgantara, T.; Widagdo, D.; Truong, L. X.

    2010-03-01

    A novel hybrid numerical-experimental method to obtain dynamic fracture properties of materials has been developed in the present work. Specimens were tested with one-point bending configuration in the Hopkinson's bar apparatus, from which the impact loading profiles were measured. In this dynamic fracture experiment, the crack tip position was measured by two strips of special strain gage having five gages arranged in one strip. Since the strain gage record only gave strain signal of each gage as a function of time, a novel method is proposed to determine the time at which the crack tip passed each strain gage and the time when the crack finally stopped. From the data of crack tip position as a function of time, the crack speed then can be calculated. These data, i.e. the loading profile and the crack speed, were then used as the input of the Node-Based FEM program developed for dynamic fractures problems. With the proposed method, three dynamic fracture properties of materials i.e dynamic fracture toughness for crack initiation (KIcd), fracture toughness for crack propagation (KID), and crack arrest toughness (KIa) can simultaneously be obtained. The results obtained from the investigation of dynamic fracture properties of Polymethyl Methacrylate (PMMA) material by the present method are well compared with the ones in the literature and from the direct experimental measurement. The good agreement suggests that the hybrid method developed in the present work can be used reliably to determine the dynamic fracture properties of materials.

  5. A hybrid numerical-experimental method for determination of dynamic fracture properties of material

    NASA Astrophysics Data System (ADS)

    Mihradi, S.; Putra, I. S.; Dirgantara, T.; Widagdo, D.; Truong, L. X.

    2009-12-01

    A novel hybrid numerical-experimental method to obtain dynamic fracture properties of materials has been developed in the present work. Specimens were tested with one-point bending configuration in the Hopkinson's bar apparatus, from which the impact loading profiles were measured. In this dynamic fracture experiment, the crack tip position was measured by two strips of special strain gage having five gages arranged in one strip. Since the strain gage record only gave strain signal of each gage as a function of time, a novel method is proposed to determine the time at which the crack tip passed each strain gage and the time when the crack finally stopped. From the data of crack tip position as a function of time, the crack speed then can be calculated. These data, i.e. the loading profile and the crack speed, were then used as the input of the Node-Based FEM program developed for dynamic fractures problems. With the proposed method, three dynamic fracture properties of materials i.e dynamic fracture toughness for crack initiation (KIcd), fracture toughness for crack propagation (KID), and crack arrest toughness (KIa) can simultaneously be obtained. The results obtained from the investigation of dynamic fracture properties of Polymethyl Methacrylate (PMMA) material by the present method are well compared with the ones in the literature and from the direct experimental measurement. The good agreement suggests that the hybrid method developed in the present work can be used reliably to determine the dynamic fracture properties of materials.

  6. DETECTORS AND EXPERIMENTAL METHODS: A method for interpolating asymmetric peak shapes in multiplet γ-ray spectra

    NASA Astrophysics Data System (ADS)

    Wang, Si-Guang; Mao, Ya-Jun; Tang, Pei-Jia; Zhu, Bo; Liang, Yu-Tie

    2009-05-01

    The peak shapes of γ-rays at various energies must be known before unfolding the multiplet spectra obtained by using semiconductor or scintillation detectors. Traditional methods describe isolated peaks with multi-parameter fitting functions, and assume that most of these parameters do not vary with energy because it is rare to find a spectrum with enough isolated peaks to constrain their dependence. We present an algorithm for interpolating the γ-ray profile at any intermediate energy given a pair of isolated γ-ray peaks from the spectrum under consideration. The algorithm is tested on experimental data and leads to a good agreement between the interpolated profile and the fitting function. This method is more accurate than the traditional approach, since all aspects of the peak shape are allowed to vary with energy. New definitions of Left-Half Width at Half Maximum, and Right-Half Width at Half Maximum for peak shape description are introduced in this paper.

  7. An experimental method for quantitatively evaluating the elemental processes of indoor radioactive aerosol behavior.

    PubMed

    Yamazawa, H; Yamada, S; Xu, Y; Hirao, S; Moriizumi, J

    2015-11-01

    An experimental method for quantitatively evaluating the elemental processes governing the indoor behaviour of naturally occurring radioactive aerosols was proposed. This method utilises transient response of aerosol concentrations to an artificial change in aerosol removal rate by turning on and off an air purifier. It was shown that the indoor-outdoor exchange rate and the indoor deposition rate could be estimated by a continuous measurement of outdoor and indoor aerosol number concentration measurements and by the method proposed in this study. Although the scatter of the estimated parameters is relatively large, both the methods gave consistent results. It was also found that the size distribution of radioactive aerosol particles and hence activity median aerodynamic diameter remained not largely affected by the operation of the air purifier, implying the predominance of the exchange and deposition processes over other processes causing change in the size distribution such as the size growth by coagulation and the size dependence of deposition.

  8. Causal attribution and Mill's methods of experimental inquiry: past, present and prospect.

    PubMed

    White, P A

    2000-09-01

    J. S. Mill proposed a set of Methods of Experimental Inquiry that were intended to guide causal inference under every conceivable set of circumstances in which experiments or observations could be carried out. The conceptual and historical relationship between these Methods and modern models of causal attribution is investigated. Mill's work retains contemporary relevance because his insights show how research can progress into presently uncharted waters. Following Mill, it is proposed that people use many different methods of causal attribution, the nature of which remains to be ascertained, and that the conditions that affect choice of method include the need to eliminate alternative causal candidates, whether single or multiple events are to be explained, the use of intervention or experiment as opposed to mere observation, and practical concerns.

  9. New experimental method for lidar overlap factor using a CCD side-scatter technique.

    PubMed

    Wang, Zhenzhu; Tao, Zongming; Liu, Dong; Wu, Decheng; Xie, Chenbo; Wang, Yingjian

    2015-04-15

    In theory, lidar overlap factor can be derived from the difference between the particle backscatter coefficient retrieved from lidar elastic signal without overlap correction and the actual particle backscatter coefficient, which can be obtained by other measured techniques. The side-scatter technique using a CCD camera is testified to be a powerful tool to detect the particle backscatter coefficient in near ground layer during night time. A new experiment approach to determine the overlap factor for vertically pointing lidar is presented in this study, which can be applied to Mie lidars. The effect of overlap factor on Mie lidar is corrected by an iteration algorithm combining the retrieved particle backscatter coefficient using CCD side-scatter method and Fernald method. This method has been successfully applied to Mie lidar measurements during a routine campaign, and the comparison of experimental results in different atmosphere conditions demonstrated that this method is available in practice.

  10. A validated spectrofluorimetric method for the determination of nifuroxazide through coumarin formation using experimental design

    PubMed Central

    2013-01-01

    Background Nifuroxazide (NF) is an oral nitrofuran antibiotic, having a wide range of bactericidal activity against gram positive and gram negative enteropathogenic organisms. It is formulated either in single form, as intestinal antiseptic or in combination with drotaverine (DV) for the treatment of gastroenteritis accompanied with gastrointestinal spasm. Spectrofluorimetry is a convenient and sensitive technique for pharmaceutical quality control. The new proposed spectrofluorimetric method allows its determination either in single form or in binary mixture with DV. Furthermore, experimental conditions were optimized using the new approach: Experimental design, which has many advantages over the old one, one variable at a time (OVAT approach). Results A novel and sensitive spectrofluorimetric method was designed and validated for the determination of NF in pharmaceutical formulation. The method was based upon the formation of a highly fluorescent coumarin compound by the reaction between NF and ethylacetoacetate (EAA) using sulfuric acid as catalyst. The fluorescence was measured at 390 nm upon excitation at 340 nm. Experimental design was used to optimize experimental conditions. Volumes of EAA and sulfuric acid, temperature and heating time were considered the critical factors to be studied in order to establish an optimum fluorescence. Each two factors were co-tried at three levels. Regression analysis revealed good correlation between fluorescence intensity and concentration over the range 20–400 ng ml-1. The suggested method was successfully applied for the determination of NF in pure and capsule forms. The procedure was validated in terms of linearity, accuracy, precision, limit of detection and limit of quantification. The selectivity of the method was investigated by analysis of NF in presence of the co-mixed drug DV where no interference was observed. The reaction pathway was suggested and the structure of the fluorescent product was proposed

  11. Study on the response of thermoluminescent dosemeters to synchrotron radiation: experimental method and Monte Carlo calculations.

    PubMed

    Bakshi, A K; Chatterjee, S; Palani Selvam, T; Dhabekar, B S

    2010-07-01

    In the present study, the energy dependence of response of some popular thermoluminescent dosemeters (TLDs) have been investigated such as LiF:Mg,Ti, LiF:Mg,Cu,P and CaSO(4):Dy to synchrotron radiation in the energy range of 10-34 keV. The study utilised experimental, Monte Carlo and analytical methods. The Monte Carlo calculations were based on the EGSnrc and FLUKA codes. The calculated energy response of all the TLDs using the EGSnrc and FLUKA codes shows excellent agreement with each other. The analytically calculated response shows good agreement with the Monte Carlo calculated response in the low-energy region. In the case of CaSO(4):Dy, the Monte Carlo-calculated energy response is smaller by a factor of 3 at all energies in comparison with the experimental response when polytetrafluoroethylene (PTFE) (75 % by wt) is included in the Monte Carlo calculations. When PTFE is ignored in the Monte Carlo calculations, the difference between the calculated and experimental response decreases (both responses are comparable >25 keV). For the LiF-based TLDs, the Monte Carlo-based response shows reasonable agreement with the experimental response.

  12. Experimental study of two material decomposition methods using multi-bin photon counting detectors

    NASA Astrophysics Data System (ADS)

    Zimmerman, Kevin C.; Sidky, Emil Y.; Gilat Schmidt, Taly

    2014-03-01

    Photon-counting detectors with multi-bin pulse height analysis (PHA) are capable of extracting energy dependent information which can be exploited for material decomposition. Iterative decomposition algorithms have been previously implemented which require prior knowledge of the source spectrum, detector spectral response, and energy threshold settings. We experimentally investigated two material decomposition methods that do not require explicit knowledge of the source spectrum and spectral response. In the first method, the effective spectrum for each energy bin is estimated from calibration transmission measurements, followed by an iterative maximum likelihood decomposition algorithm. The second investigated method, first proposed and tested through simulations by Alvarez, uses a linearized maximum likelihood estimator which requires calibration transmission measurements. The Alvarez method has the advantage of being non-iterative. This study experimentally quantified and compared the material decomposition bias, as a percentage of material thickness, and standard deviation resulting from these two material decomposition estimators. Multi-energy x-ray transmission measurements were acquired through varying thicknesses of Teon, Delrin, and neoprene at two different flux settings and decomposed into PMMA and aluminum thicknesses using the investigated methods. In addition, a series of 200 equally spaced projections of a rod phantom were acquired over 360°. The multi-energy sinograms were decomposed using both empirical methods and then reconstructed using filtered backprojection producing two images representing each basis material. The Alvarez method decomposed Delrin into PMMA with a bias of 0.5-19% and decomposed neoprene into aluminum with a bias of less than 3%. The spectral estimation method decomposed Delrin into PMMA with a bias of 0.6-16% and decomposed neoprene into aluminum with a bias of 0.1-58%. In general, the spectral estimation method resulted in

  13. Validation of experimental whole-body SAR assessment method in a complex indoor environment.

    PubMed

    Bamba, Aliou; Joseph, Wout; Vermeeren, Gunter; Tanghe, Emmeric; Gaillot, Davy Paul; Andersen, Jørgen B; Nielsen, Jesper Ødum; Lienard, Martine; Martens, Luc

    2013-02-01

    Experimentally assessing the whole-body specific absorption rate (SAR(wb) ) in a complex indoor environment is very challenging. An experimental method based on room electromagnetics theory (accounting only the line-of-sight as specular path) is validated using numerical simulations with the finite-difference time-domain method. Furthermore, the method accounts for diffuse multipath components (DMC) in the total absorption rate by considering the reverberation time of the investigated room, which describes all the losses in a complex indoor environment. The advantage of the proposed method is that it allows discarding the computational burden because it does not use any discretizations. Results show good agreement between measurement and computation at 2.8 GHz, as long as the plane wave assumption is valid, that is, at large distances from the transmitter. Relative deviations of 0.71% and 4% have been obtained for far-field scenarios, and 77.5% for the near field-scenario. The contribution of the DMC in the total absorption rate is also quantified here, which has never been investigated before. It is found that the DMC may represent an important part of the total absorption rate; its contribution may reach up to 90% for certain scenarios in an indoor environment.

  14. Thermophysical properties of medium density fiberboards measured by quasi-stationary method: experimental and numerical evaluation

    NASA Astrophysics Data System (ADS)

    Troppová, Eva; Tippner, Jan; Hrčka, Richard

    2017-01-01

    This paper presents an experimental measurement of thermal properties of medium density fiberboards with different thicknesses (12, 18 and 25 mm) and sample sizes (50 × 50 mm and 100 × 100 mm) by quasi-stationary method. The quasi-stationary method is a transient method which allows measurement of three thermal parameters (thermal conductivity, thermal diffusivity and heat capacity). The experimentally gained values were used to verify a numerical model and furthermore served as input parameters for the numerical probabilistic analysis. The sensitivity of measured outputs (time course of temperature) to influential factors (density, heat transfer coefficient and thermal conductivities) was established and described by the Spearman's rank correlation coefficients. The dependence of thermal properties on density was confirmed by the data measured. Density was also proved to be an important factor for sensitivity analyses as it highly correlated with all output parameters. The accuracy of the measurement method can be improved based on the results of the probabilistic analysis. The relevancy of the experiment is mainly influenced by the choice of a proper ratio between thickness and width of samples.

  15. A new experimental method for in situ corrosion monitoring under alternate wet-dry conditions.

    PubMed

    Fu, Xinxin; Dong, Junhua; Han, Enhou; Ke, Wei

    2009-01-01

    A new experimental method was applied in in situ corrosion monitoring of mild steel Q235 under alternate wet-dry conditions. The thickness of the electrolyte film during the wet cycle was monitored by a high-precision balance with a sensibility of 0.1 mg. At the same time, an electrochemical impedance technique was employed to study the effect of film thickness on corrosion rates. Experimental results showed that there was a critical electrolyte film condition for which the corrosion rate reached a maximum during wet-dry cycles. For the substrate, the critical condition could be described by a film thickness of about 17 μm. For the rusted specimen, the critical condition could be described by an electrolyte amount of about 0.038 g, which is equivalent to a film thickness of 38 μm. This monitoring system was very useful for studying atmospheric corrosion of metals covered by corrosion products.

  16. Experimental methods and transport models for drug delivery across the blood-brain barrier.

    PubMed

    Fu, Bingmei M

    2012-06-01

    The blood-brain barrier (BBB) is a dynamic barrier essential for maintaining the micro-environment of the brain. Although the special anatomical features of the BBB determine its protective role for the central nervous system (CNS) from blood-born neurotoxins, however, the BBB extremely limits the therapeutic efficacy of drugs into the CNS, which greatly hinders the treatment of major brain diseases. This review summarized the unique structures of the BBB, described a variety of in vivo and in vitro experimental methods for determining the transport properties of the BBB, e.g., the permeability of the BBB to water, ions, and solutes including nutrients, therapeutic agents and drug carriers, and presented newly developed mathematical models which quantitatively correlate the anatomical structures of the BBB with its barrier functions. Finally, on the basis of the experimental observations and the quantitative models, several strategies for drug delivery through the BBB were proposed.

  17. Direction and Integration of Experimental Ground Test Capabilities and Computational Methods

    NASA Technical Reports Server (NTRS)

    Dunn, Steven C.

    2016-01-01

    This paper groups and summarizes the salient points and findings from two AIAA conference panels targeted at defining the direction, with associated key issues and recommendations, for the integration of experimental ground testing and computational methods. Each panel session utilized rapporteurs to capture comments from both the panel members and the audience. Additionally, a virtual panel of several experts were consulted between the two sessions and their comments were also captured. The information is organized into three time-based groupings, as well as by subject area. These panel sessions were designed to provide guidance to both researchers/developers and experimental/computational service providers in defining the future of ground testing, which will be inextricably integrated with the advancement of computational tools.

  18. Adaptive support for aircraft panel testing: New method and its experimental verification on a beam structure

    NASA Astrophysics Data System (ADS)

    Sachau, Delf; Baschke, Manuel

    2017-04-01

    Acoustic transmissibility of aircraft panels is measured in full-scale test rigs. The panels are supported at their frames. These boundary conditions do not take into account the dynamic influence of the fuselage, which is significant in the frequency range below 300 Hz. This paper introduces a new adaptive boundary system (ABS). It combines accelerometers and electrodynamic shakers with real-time signal processing. The ABS considers the dynamic effect of the fuselage on the panel. The frames are dominating the dynamic behaviour of a fuselage in the low-frequency range. Therefore, the new method is applied to a beam representing a frame of the aircraft structure. The experimental results are evaluated and the precision of the ABS is discussed. The theoretical apparent mass representing the cut-off part of a frame is calculated and compared with the apparent mass, as provided by the ABS. It is explained how the experimental set-up limits the precision of the ABS.

  19. Experimental Methods and Transport Models for Drug Delivery across the Blood-Brain Barrier

    PubMed Central

    Fu, Bingmei M

    2017-01-01

    The blood-brain barrier (BBB) is a dynamic barrier essential for maintaining the micro-environment of the brain. Although the special anatomical features of the BBB determine its protective role for the central nervous system (CNS) from blood-born neurotoxins, however, the BBB extremely limits the therapeutic efficacy of drugs into the CNS, which greatly hinders the treatment of major brain diseases. This review summarized the unique structures of the BBB, described a variety of in vivo and in vitro experimental methods for determining the transport properties of the BBB, e.g., the permeability of the BBB to water, ions, and solutes including nutrients, therapeutic agents and drug carriers, and presented newly developed mathematical models which quantitatively correlate the anatomical structures of the BBB with its barrier functions. Finally, on the basis of the experimental observations and the quantitative models, several strategies for drug delivery through the BBB were proposed. PMID:22201587

  20. Experimental design applied to spin coating of 2D colloidal crystal masks: a relevant method?

    PubMed

    Colson, Pierre; Cloots, Rudi; Henrist, Catherine

    2011-11-01

    Monolayers of colloidal spheres are used as masks in nanosphere lithography (NSL) for the selective deposition of nanostructured layers. Several methods exist for the formation of self-organized particle monolayers, among which spin coating appears to be very promising. However, a spin coating process is defined by several parameters like several ramps, rotation speeds, and durations. All parameters influence the spreading and drying of the droplet containing the particles. Moreover, scientists are confronted with the formation of numerous defects in spin coated layers, limiting well-ordered areas to a few micrometers squared. So far, empiricism has mainly ruled the world of nanoparticle self-organization by spin coating, and much of the literature is experimentally based. Therefore, the development of experimental protocols to control the ordering of particles is a major goal for further progress in NSL. We applied experimental design to spin coating, to evaluate the efficiency of this method to extract and model the relationships between the experimental parameters and the degree of ordering in the particles monolayers. A set of experiments was generated by the MODDE software and applied to the spin coating of latex suspension (diameter 490 nm). We calculated the ordering by a homemade image analysis tool. The results of partial least squares (PLS) modeling show that the proposed mathematical model only fits data from strictly monolayers but is not predictive for new sets of parameters. We submitted the data to principal component analysis (PCA) that was able to explain 91% of the results when based on strictly monolayered samples. PCA shows that the ordering was positively correlated to the ramp time and negatively correlated to the first rotation speed. We obtain large defect-free domains with the best set of parameters tested in this study. This protocol leads to areas of 200 μm(2), which has never been reported so far.

  1. Modelling the fibrous tissue layer in cemented hip replacements: experimental and finite element methods.

    PubMed

    Waide, V; Cristofolini, L; Stolk, J; Verdonschot, N; Boogaard, G J; Toni, A

    2004-01-01

    The long-term fixation of cemented femoral components may be jeopardised by the presence of a fibrous tissue layer at the bone-cement interface. This study used both experimental and finite element (FE) methods to investigate the load transfer characteristics of two types of cemented hip replacements (Lubinus SPII and Müller-Curved) with a fibrous tissue layer. The experimental part investigated six stems of each type, where these were implanted in composite femurs with a specially selected silicone elastomer modelling the soft interfacial layer. Two fibrous tissue conditions were examined: a layer covering the full cement mantle, representing a revision condition; and a layer covering the proximal portion of the cement mantle, representing a non-revised implant with partial debonding and fibrous tissue formation. The FE method was used to model the full fibrous tissue layer condition, for both implants. The layer was modelled as a homogeneous, linearly isotropic material. A cross-comparison was performed of the experimental and FE findings. Agreement between experimental and FE models was verified to be within 15%. Varying the stiffness parameter of the FE soft tissue layer had little influence on the cortical bone strains, though had considerable effect on the cement strains. Stress shielding occurred for both stems under both fibrous tissue conditions, with the greatest reduction around the calcar. However, the cortical bone strains were generally larger than those for the equivalent well-fixed stems. The fibrous tissue layer was not found to increase the general strain pattern of the cement mantle, though localised regions of high stress were detected.

  2. A simple method of catalase purification for the undergraduate experimental course.

    PubMed

    Chen, Qian; Cheng, Meng; Wang, Yinnan; Yao, Ming; Chen, Yongchun; Gao, Yuan; Ding, Wenyuan

    2015-02-01

    Catalase is a characteristic enzyme of peroxisomes, of which it is the most abundant protein. This enzyme serves as a typical example of a peroxisomal enzyme and is important in the teaching of biochemistry and molecular biology. Although there is substantial information regarding catalase purification, purifying catalase for the junior‑grade undergraduate experimental course face challenges in obtaining materials and increasingly expensive purification equipment. This study presents a simple method for the purification of mouse liver catalase using ethanol‑chloroform treatment, sodium sulfate fractionation, dialysis and Sephadex G‑200 gel filtration chromatography. Catalase was purified 31.8‑fold with an 18.3% yield. The advantages of this method were its low operating environment requirements, simple procedure and reduced cost. Furthermore, the method was designed to improve students' comprehensive ability and manipulative ability and to introduce a sense of innovation in the fields of biochemistry and molecular biology during their junior year.

  3. Experimental Scatter Correction Methods in Industrial X-Ray Cone-Beam CT

    NASA Astrophysics Data System (ADS)

    Schörner, K.; Goldammer, M.; Stephan, J.

    2011-06-01

    Scattered radiation presents a major source of image degradation in industrial cone-beam computed tomography systems. Scatter artifacts introduce streaks, cupping and a loss of contrast in the reconstructed CT-volumes. In order to overcome scatter artifacts, we present two complementary experimental correction methods: the beam-stop array (BSA) and an inverse technique we call beam-hole array (BHA). Both correction methods are examined in comparative measurements where it is shown that the aperture-based BHA technique has practical and scatter-reducing advantages over the BSA. The proposed BHA correction method is successfully applied to a large-scale industrial specimen whereby scatter artifacts are reduced and contrast is enhanced significantly.

  4. Air cooling : an experimental method of evaluating the cooling effect of air streams on air-cooled cylinders

    NASA Technical Reports Server (NTRS)

    Alcock, J F

    1927-01-01

    In this report is described an experimental method which the writer has evolved for dealing with air-cooled engines, and some of the data obtained by its means. Methods of temperature measurement and cooling are provided.

  5. Uncovering noisy social signals: Using optimization methods from experimental physics to study social phenomena.

    PubMed

    Kaptein, Maurits; van Emden, Robin; Iannuzzi, Davide

    2017-01-01

    Due to the ubiquitous presence of treatment heterogeneity, measurement error, and contextual confounders, numerous social phenomena are hard to study. Precise control of treatment variables and possible confounders is often key to the success of studies in the social sciences, yet often proves out of the realm of control of the experimenter. To amend this situation we propose a novel approach coined "lock-in feedback" which is based on a method that is routinely used in high-precision physics experiments to extract small signals out of a noisy environment. Here, we adapt the method to noisy social signals in multiple dimensions and evaluate it by studying an inherently noisy topic: the perception of (subjective) beauty. We show that the lock-in feedback approach allows one to select optimal treatment levels despite the presence of considerable noise. Furthermore, through the introduction of an external contextual shock we demonstrate that we can find relationships between noisy variables that were hitherto unknown. We therefore argue that lock-in methods may provide a valuable addition to the social scientist's experimental toolbox and we explicitly discuss a number of future applications.

  6. Uncovering noisy social signals: Using optimization methods from experimental physics to study social phenomena

    PubMed Central

    2017-01-01

    Due to the ubiquitous presence of treatment heterogeneity, measurement error, and contextual confounders, numerous social phenomena are hard to study. Precise control of treatment variables and possible confounders is often key to the success of studies in the social sciences, yet often proves out of the realm of control of the experimenter. To amend this situation we propose a novel approach coined “lock-in feedback” which is based on a method that is routinely used in high-precision physics experiments to extract small signals out of a noisy environment. Here, we adapt the method to noisy social signals in multiple dimensions and evaluate it by studying an inherently noisy topic: the perception of (subjective) beauty. We show that the lock-in feedback approach allows one to select optimal treatment levels despite the presence of considerable noise. Furthermore, through the introduction of an external contextual shock we demonstrate that we can find relationships between noisy variables that were hitherto unknown. We therefore argue that lock-in methods may provide a valuable addition to the social scientist’s experimental toolbox and we explicitly discuss a number of future applications. PMID:28306728

  7. Experimental study of permanent displacement estimate method based on strong-motion earthquake accelerograms

    NASA Astrophysics Data System (ADS)

    Lu, Tao; Hu, Guorui

    2016-04-01

    In the engineering seismology studies, the seismic permanent displacement of the near-fault site is often obtained by the process of the ground motion accelerogram recorded by the instrument on the station. Because of the selection differences of the estimate methods and the algorithm parameters, the strongly different results of the permanent displacement is gotten often. And the reliability of the methods has not only been proved in fact, but also the selection of the algorithm parameters has to be carefully considered. In order to solve this problem, the experimental study on the permanent displacement according to the accelerogram was carried out with the experiment program of using the large shaking table and the sliding mechanism in the earthquake engineering laboratory. In the experiments,the large shaking table genarated the dynamincs excitation without the permanent displacement,the sliding mechanism fixed on the shaking table genarated the permanent displacement, and the accelerogram including the permant information had been recorded by the instrument on the sliding mechanism.Then the permanent displacement value had been obtained according to the accelerogram, and been compared with the displacement value gotten by the displacement meter and the digital close range photogrammetry. The experimental study showed that the reliable permanent displacement could be obtained by the existing processing method under the simple laboratory conditions with the preconditions of the algorithm parameters selection carefully.

  8. Method of extraction of the Mueller-Jones part out of an experimental Mueller matrix

    NASA Astrophysics Data System (ADS)

    Savenkov, Sergey N.; Marienko, Valeri V.

    1997-05-01

    Properly measured experimental Mueller matrix contains complete information on depolarization, anisotropy properties of studied object and on value of isotropic change of probated radiation intensity by studied object as well. They know that Jones matrix contains complete information on value of isotropic change of probated radiation intensity and on anisotropy properties of studied object. Thus, in the case of absent of depolarization and measurement errors reducing to existence of, so called, overpolarization there exist a one-to-one correspondence between Mueller and Jones matrix. Mueller matrix will then be called a Mueller-Jones matrix. The possibility of extraction of Mueller-Jones part out of any experimental Mueller matrix is extremely important because of following. First, it allows us to obtain everything about depolarization properties of studied object directly. Depolarization is very informative 'object' and now, in the majority, one knows little about its nature and methods of its complete description. Second, one gets the possibility to operate with correspondent Jones matrix to analyze of which there exist the powerful methods such as solving of the spectral problem and application of the decomposition theorem formerly proved by the present authors. The distinctive feature of the method proposed here is that it allows us in the best way to take into consideration the important fact that far from all elements of initial Mueller matrix contains information on depolarization.

  9. 75 FR 71155 - Market Test of Experimental Product: “Alternative Postage Payment Method for Greeting Cards”

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-22

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Market Test of Experimental Product: ``Alternative Postage Payment Method for Greeting Cards'' AGENCY: Postal... Postage Payment Method for Greeting Cards'' experimental product on January 2, 2011. The Postal Service...

  10. Effect Sizes as Result Interpretation Aids in Single-Subject Experimental Research: Description and Application of Four Nonoverlap Methods

    ERIC Educational Resources Information Center

    Rakap, Salih

    2015-01-01

    Single-subject experimental research (SSER), one of the most commonly used research methods in special education and applied behaviour analysis, is a scientific, rigorous and valid method to evaluate the effectiveness of behavioural, educational and psychological treatments. However, studies using single-subject experimental research designs are…

  11. Effect Sizes as Result Interpretation Aids in Single-Subject Experimental Research: Description and Application of Four Nonoverlap Methods

    ERIC Educational Resources Information Center

    Rakap, Salih

    2015-01-01

    Single-subject experimental research (SSER), one of the most commonly used research methods in special education and applied behaviour analysis, is a scientific, rigorous and valid method to evaluate the effectiveness of behavioural, educational and psychological treatments. However, studies using single-subject experimental research designs are…

  12. A novel experimental mechanics method for measuring the light pressure acting on a solar sail membrane

    NASA Astrophysics Data System (ADS)

    Shi, Aiming; Jiang, Li; Dowell, Earl H.; Qin, Zhixuan

    2017-02-01

    Solar sail is a high potential `sailing craft' for interstellar exploration. The area of the first flight solar sail demonstrator named "IKAROS" is 200 square meters. Future interplanetary missions will require solar sails at least on the order of 10000 square meters (or larger). Due to the limitation of ground facilities, the size of experimental sample should not be large. Furthermore the ground experiments have to be conducted in gravitational field, so the gravity effect must be considered in a ground test. To obtain insight into the solar sail membrane dynamics, a key membrane flutter (or limit cycle oscillations) experiment with light forces acting on it must be done. But one big challenge is calibrating such a tiny light force by as a function of the input power. In this paper, a gravity-based measuring method for light pressure acting on membrane is presented. To explain the experimental principle, an ideal example of a laser beam with expanders and a metal film is studied. Based on calculations, this experimental mechanics method for calibrating light pressure with an accuracy of 0.01 micro-Newton may be realized by making the light force balance the gravity force on the metal films. This gravity-based measuring method could not only be applied to study the dynamics characteristics of solar sail membrane structure with different light forces, but could also be used to determine more accurate light forces/loads acting on solar sail films and hence to enhance the determination of the mechanical properties of the solar sail membrane structure.

  13. Experimental method for characterizing CVOC removal from fractured clays during boiling

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoling; Tan, Tianwu; Falta, Ronald W.; Murdoch, Lawrence C.

    2013-09-01

    Conventional remediation methods that rely on contact with contaminants can be ineffective in fractured media, but thermal methods of remediation involving CVOC stripping at boiling temperature show promise. However, limited experimental data are available to characterize thermal remediation because of challenges associated with high temperature. This research reports an experimental method using uniformly contaminated clay packed into two types of experimental cells, a rigid-wall stainless steel tube and a flexible-wall Teflon tube in a pressurized chamber. Both tubes are 5 cm in diameter and approximately 25 cm long. This laboratory apparatus was developed as a 1D physical model for contaminant transport in a cylindrical matrix towards a fracture, which is represented by one end of the cylinder and serves as the outlet of vapor and contaminant. The clay was contaminated with dissolved 1,2-dichloroethane (DCA) and bromide, and the columns were heated to more than 100 °C and then the top end was depressurized to atmospheric pressure to induce boiling. The outflow was condensed and analyzed for contaminant mass. The flexible-wall cell was confined to 100 kPa (gage), allowing equilibrium boiling temperatures of approximately 120 °C to be maintained. The clay was sampled before and after heating and extracted to determine the DCA distribution along the length of the column. During a typical test in the rigid-wall cell, internal temperatures and pressures along the column during heating reached the saturated vapor pressure curve. DCA concentrations in the recovered condensate were up to 12 times of the initial pore concentration in the clay. Less than 5% of non-volatile bromide was recovered. Significant removal of DCA and water occurred along the entire length of the clay column. This suggests that boiling was occurring in the clay matrix.

  14. Experimental method for characterizing CVOC removal from fractured clays during boiling.

    PubMed

    Liu, Xiaoling; Tan, Tianwu; Falta, Ronald W; Murdoch, Lawrence C

    2013-09-01

    Conventional remediation methods that rely on contact with contaminants can be ineffective in fractured media, but thermal methods of remediation involving CVOC stripping at boiling temperature show promise. However, limited experimental data are available to characterize thermal remediation because of challenges associated with high temperature. This research reports an experimental method using uniformly contaminated clay packed into two types of experimental cells, a rigid-wall stainless steel tube and a flexible-wall Teflon tube in a pressurized chamber. Both tubes are 5 cm in diameter and approximately 25 cm long. This laboratory apparatus was developed as a 1D physical model for contaminant transport in a cylindrical matrix towards a fracture, which is represented by one end of the cylinder and serves as the outlet of vapor and contaminant. The clay was contaminated with dissolved 1,2-dichloroethane (DCA) and bromide, and the columns were heated to more than 100 °C and then the top end was depressurized to atmospheric pressure to induce boiling. The outflow was condensed and analyzed for contaminant mass. The flexible-wall cell was confined to 100 kPa (gage), allowing equilibrium boiling temperatures of approximately 120 °C to be maintained. The clay was sampled before and after heating and extracted to determine the DCA distribution along the length of the column. During a typical test in the rigid-wall cell, internal temperatures and pressures along the column during heating reached the saturated vapor pressure curve. DCA concentrations in the recovered condensate were up to 12 times of the initial pore concentration in the clay. Less than 5% of non-volatile bromide was recovered. Significant removal of DCA and water occurred along the entire length of the clay column. This suggests that boiling was occurring in the clay matrix. © 2013.

  15. An experimental method for directly determining the interconnectivity of melt in a partially molten system

    NASA Technical Reports Server (NTRS)

    Daines, Martha J.; Richter, Frank M.

    1988-01-01

    An experimental method for directly determining the degree of interconnectivity of melt in a partially molten system is discussed using an olivine-basalt system as an example. Samarium 151 is allowed time to diffuse through mixtures of olivine and basalt powder which have texturally equilibrated at 1350 C and 13 to 15 kbars. The final distribution of samarium is determined through examination of developed radiographs of the samples. Results suggest an interconnected melt network is established at melt fractions at least as low as 1 wt pct and all melt is completely interconnected at melt fractions at least as low as 2 wt pct for the system examined.

  16. Method of experimental determination of the kinetic constants in fast polymerization reactions in nonisothermal diffusion conditions

    SciTech Connect

    Prochukhan, Yu.A.; Berlin, A.A.; Enikolopyan, N.S.

    1986-09-01

    A new method for the experimental determination of the kinetic constants k/sub p/ and k/sub t/ in fast polymerization reactions on the example of cationic (under the effect of AlCl/sub 3/, BF/sub 3/, and other catalysts) liquid phase polymerization of isobutylene in a flow was suggested. The study of the macrokinetic features of low-temperature polymerization of isobutylene revealed the specific conditions of the occurrence of the process (quasi-ideal displacement) which are characterized by the relative constancy and uniformity of the distribution of the concentrations of the reacting substances along the flow section.

  17. Highly porous thermal protection materials: Modelling and prediction of the methodical experimental errors

    NASA Astrophysics Data System (ADS)

    Cherepanov, Valery V.; Alifanov, Oleg M.; Morzhukhina, Alena V.; Budnik, Sergey A.

    2016-11-01

    The formation mechanisms and the main factors affecting the systematic error of thermocouples were investigated. According to the results of experimental studies and mathematical modelling it was established that in highly porous heat resistant materials for aerospace application the thermocouple errors are determined by two competing mechanisms provided correlation between the errors and the difference between radiation and conduction heat fluxes. The comparative analysis was carried out and some features of the methodical error formation related to the distances from the heated surface were established.

  18. Experimental methods in the study of neutron scattering at small angles

    SciTech Connect

    Dragolici, Cristian A.

    2014-11-24

    Small angle scattering (SAS) is the collective name given to the techniques of small angle neutron (SANS) and X-ray (SAXS) scattering. They offer the possibility to analyze particles without disturbing their natural environment. In each of these techniques radiation is elastically scattered by a sample and the resulting scattering pattern is analyzed to provide information about the size, shape and orientation of some component of the sample. Accordingly, a large number of methods and experimental patterns have been developed to ease the investigation of condensed matter by use of these techniques. Some of them are the discussed in this paper.

  19. An experimental method for directly determining the interconnectivity of melt in a partially molten system

    NASA Technical Reports Server (NTRS)

    Daines, Martha J.; Richter, Frank M.

    1988-01-01

    An experimental method for directly determining the degree of interconnectivity of melt in a partially molten system is discussed using an olivine-basalt system as an example. Samarium 151 is allowed time to diffuse through mixtures of olivine and basalt powder which have texturally equilibrated at 1350 C and 13 to 15 kbars. The final distribution of samarium is determined through examination of developed radiographs of the samples. Results suggest an interconnected melt network is established at melt fractions at least as low as 1 wt pct and all melt is completely interconnected at melt fractions at least as low as 2 wt pct for the system examined.

  20. A new method for control of networked systems with an experimental verification.

    PubMed

    Rahmani, Behrooz; Markazi, Amir H D; Seyfi, Behzad

    2015-05-01

    This paper presents a variable selective control methodology for control of networked systems subject to transfer delay, packet-loss and packet-disordering. This approach is based upon the extension of the variable sampling period idea with a new packet based control methodology. In this way, corresponding to a range of expected time delays, a number of step-invariant discrete-time plant models are considered and based on them, a switching observer-based controller is designed by solving linear matrix inequalities (LMIs). A sufficient condition for closed-loop asymptotic stability is derived. Simulation and experimental investigations demonstrate the effectiveness of the proposed method in the real world.

  1. TiO2 synthesized by microwave assisted solvothermal method: Experimental and theoretical evaluation

    NASA Astrophysics Data System (ADS)

    Moura, K. F.; Maul, J.; Albuquerque, A. R.; Casali, G. P.; Longo, E.; Keyson, D.; Souza, A. G.; Sambrano, J. R.; Santos, I. M. G.

    2014-02-01

    In this study, a microwave assisted solvothermal method was used to synthesize TiO2 with anatase structure. The synthesis was done using Ti (IV) isopropoxide and ethanol without templates or alkalinizing agents. Changes in structural features were observed with increasing time of synthesis and evaluated using periodic quantum chemical calculations. The anatase phase was obtained after only 1 min of reaction besides a small amount of brookite phase. Experimental Raman spectra are in accordance with the theoretical one. Micrometric spheres constituted by nanometric particles were obtained for synthesis from 1 to 30 min, while spheres and sticks were observed after 60 min.

  2. An inverse finite element method for beam shape sensing: theoretical framework and experimental validation

    NASA Astrophysics Data System (ADS)

    Gherlone, Marco; Cerracchio, Priscilla; Mattone, Massimiliano; Di Sciuva, Marco; Tessler, Alexander

    2014-04-01

    Shape sensing, i.e., reconstruction of the displacement field of a structure from surface-measured strains, has relevant implications for the monitoring, control and actuation of smart structures. The inverse finite element method (iFEM) is a shape-sensing methodology shown to be fast, accurate and robust. This paper aims to demonstrate that the recently presented iFEM for beam and frame structures is reliable when experimentally measured strains are used as input data. The theoretical framework of the methodology is first reviewed. Timoshenko beam theory is adopted, including stretching, bending, transverse shear and torsion deformation modes. The variational statement and its discretization with C0-continuous inverse elements are briefly recalled. The three-dimensional displacement field of the beam structure is reconstructed under the condition that least-squares compatibility is guaranteed between the measured strains and those interpolated within the inverse elements. The experimental setup is then described. A thin-walled cantilevered beam is subjected to different static and dynamic loads. Measured surface strains are used as input data for shape sensing at first with a single inverse element. For the same test cases, convergence is also investigated using an increasing number of inverse elements. The iFEM-recovered deflections and twist rotations are then compared with those measured experimentally. The accuracy, convergence and robustness of the iFEM with respect to unavoidable measurement errors, due to strain sensor locations, measurement systems and geometry imperfections, are demonstrated for both static and dynamic loadings.

  3. A method for studying jaw muscle activity during standardized jaw movements under experimental jaw muscle pain.

    PubMed

    Sae-Lee, Daraporn; Wanigaratne, Kamal; Whittle, Terry; Peck, Christopher C; Murray, Greg M

    2006-10-30

    This paper describes a method for studying superficial and deep jaw muscle activity during standardized jaw movements under experimental jaw muscle pain. In 22 healthy adults, pain was elicited in the right masseter muscle via tonic infusion of 4.5% hypertonic saline and which resulted in scores of 30-60 mm on a 100-mm visual analogue scale. Subjects performed tasks in five sessions in a repeated measures design, i.e., control 1, test 1 (during hypertonic or isotonic saline infusion), control 2 (without infusion), test 2 (during isotonic or hypertonic saline infusion), control 3 (without infusion). During each session, subjects performed maximal clenching and standardized jaw tasks, i.e., protrusion, lateral excursion, open/close, chewing. Mandibular movement was recorded with a 6-degree-of-freedom tracking system simultaneously with electromyographic (EMG) activity from the inferior head of the lateral pterygoid muscle with fine-wire electrodes (verified by computer tomography), and from posterior temporalis, the submandibular muscle group and bilateral masseter muscles with surface electrodes. EMG root mean square values were calculated at each 0.5 mm increment of mandibular incisor movement for all tasks under each experimental session. This establishes an experimental model for testing the effects of pain on jaw muscle activity where the jaw motor system is required to perform goal-directed tasks, and therefore should extend our understanding of the effects of pain on the jaw motor system.

  4. An experimental evaluation method for the performance of a laser line scanning system with multiple sensors

    NASA Astrophysics Data System (ADS)

    Tian, Qingguo; Yang, Yujie; Zhang, Xiangyu; Ge, Baozhen

    2014-01-01

    Laser line scanning 3D digitising systems have a wide range of applications. Their working performance is mainly determined by the system calibration procedure and is also affected by the working conditions, CCD camera imperfections, and object surface optical characteristics. Therefore, a comprehensive evaluation of working performance is necessary before and during use. This study proposes an experimental method for the performance evaluation of a laser line scanner (LLS) with 8 scanning sensors developed in our laboratory. This method first obtains the dense point clouds of standard parts composed of disks, cylinders, and squares. Next, the single-layer point clouds located in horizontal planes of different heights are fitted using the least squares method to obtain the enclosed contours S. Three parameters, namely, the standard deviation of the distance distribution between points and S, the mean distance of the distance distribution, and the shape feature sizes, are used to evaluate the performance. The proposed method evaluates both the scanner as a whole and each scanning sensor. Using this method, more comprehensive information can be acquired to evaluate the scanner performance. The experimental results show that the absolute dimension size error and relative error are less than 5 mm and 3%, respectively, and the relative shape error is less than 2%; therefore, the evaluated LLS system can meet the requirements for human anthropometry applications. Although each scanning sensor has different random and systematic error, these errors are the function of measurement depth. These conclusions are helpful for the further use of this scanner system and can be utilised to optimise this LLS system further.

  5. Analysis Method and Experimental Conditions Affect Computed Circadian Phase from Melatonin Data

    PubMed Central

    Klerman, Hadassa; St. Hilaire, Melissa A.; Kronauer, Richard E.; Gooley, Joshua J.; Gronfier, Claude; Hull, Joseph T.; Lockley, Steven W.; Santhi, Nayantara; Wang, Wei; Klerman, Elizabeth B.

    2012-01-01

    Accurate determination of circadian phase is necessary for research and clinical purposes because of the influence of the master circadian pacemaker on multiple physiologic functions. Melatonin is presently the most accurate marker of the activity of the human circadian pacemaker. Current methods of analyzing the plasma melatonin rhythm can be grouped into three categories: curve-fitting, threshold-based and physiologically-based linear differential equations. To determine which method provides the most accurate assessment of circadian phase, we compared the ability to fit the data and the variability of phase estimates for seventeen different markers of melatonin phase derived from these methodological categories. We used data from three experimental conditions under which circadian rhythms - and therefore calculated melatonin phase - were expected to remain constant or progress uniformly. Melatonin profiles from older subjects and subjects with lower melatonin amplitude were less likely to be fit by all analysis methods. When circadian drift over multiple study days was algebraically removed, there were no significant differences between analysis methods of melatonin onsets (P = 0.57), but there were significant differences between those of melatonin offsets (P<0.0001). For a subset of phase assessment methods, we also examined the effects of data loss on variability of phase estimates by systematically removing data in 2-hour segments. Data loss near onset of melatonin secretion differentially affected phase estimates from the methods, with some methods incorrectly assigning phases too early while other methods assigning phases too late; missing data at other times did not affect analyses of the melatonin profile. We conclude that melatonin data set characteristics, including amplitude and completeness of data collection, differentially affect the results depending on the melatonin analysis method used. PMID:22511928

  6. Development of advanced methods for analysis of experimental data in diffusion

    NASA Astrophysics Data System (ADS)

    Jaques, Alonso V.

    There are numerous experimental configurations and data analysis techniques for the characterization of diffusion phenomena. However, the mathematical methods for estimating diffusivities traditionally do not take into account the effects of experimental errors in the data, and often require smooth, noiseless data sets to perform the necessary analysis steps. The current methods used for data smoothing require strong assumptions which can introduce numerical "artifacts" into the data, affecting confidence in the estimated parameters. The Boltzmann-Matano method is used extensively in the determination of concentration - dependent diffusivities, D(C), in alloys. In the course of analyzing experimental data, numerical integrations and differentiations of the concentration profile are performed. These methods require smoothing of the data prior to analysis. We present here an approach to the Boltzmann-Matano method that is based on a regularization method to estimate a differentiation operation on the data, i.e., estimate the concentration gradient term, which is important in the analysis process for determining the diffusivity. This approach, therefore, has the potential to be less subjective, and in numerical simulations shows an increased accuracy in the estimated diffusion coefficients. We present a regression approach to estimate linear multicomponent diffusion coefficients that eliminates the need pre-treat or pre-condition the concentration profile. This approach fits the data to a functional form of the mathematical expression for the concentration profile, and allows us to determine the diffusivity matrix directly from the fitted parameters. Reformulation of the equation for the analytical solution is done in order to reduce the size of the problem and accelerate the convergence. The objective function for the regression can incorporate point estimations for error in the concentration, improving the statistical confidence in the estimated diffusivity matrix

  7. New method of the polymeric material properties experimental investigation under powerful energy flux impact

    NASA Astrophysics Data System (ADS)

    Demidov, B. A.; Efremov, V. P.; Kalinin, Yu G.; Kazakov, E. D.; Metelkin, S. Yu; Petrov, V. A.; Potapenko, A. I.

    2015-11-01

    Investigation of the polymeric material properties under powerfull energy flux impact is relevant as for basic research (mathematical modeling of polymeric materials behavior in extreme conditions, testing the state equations), as for practical applications (for testing of protective coatings for space research and laboratory facilities). This paper presents the results of experimental studies of the interaction of polymeric materials with a relativistic electron beam produced by a high-current electron accelerator Calamary. Calamary facility provides a wide range of electron beam parameters: diameter 10-15 mm, the voltage on the diode up to 300 kV, the current through the diode up to 30 kA. New method of beam-target interaction area measurement was developed. The original method for the mechanical kick impulse measuring based on piezoelectric vibration sensor was presented. The dependence of the kick impulse from the power flux was obtained.

  8. Experimental and Statistical Evaluation of Cutting Methods in Relation to Specific Energy and Rock Properties

    NASA Astrophysics Data System (ADS)

    Engin, Irfan Celal; Bayram, Fatih; Yasitli, Nazmi Erhan

    2013-07-01

    In a processing plant, natural stone can be cut by methods such as circular sawing (CS), frame sawing (FS), water jet cutting (WJC) and abrasive water jet cutting (AWJC). The efficiency of cutting systems can be compared using various parameters. In this study, the specific energy values were determined and compared to evaluate the efficiency of rock-cutting methods. Rock-cutting experiments were performed on 12 different types of rock samples using a circular sawing machine and an AWJC machine. The experimental results showed that the specific energy values in AWJC were generally higher than in CS. In addition, the relationships between specific energy values and rock properties were explained in this study. The Shore hardness and abrasion resistance were found to be strongly related to the specific energy values, and according to these parameters prediction charts of specific energy values were created.

  9. An experimental method for measuring stress intensity factor distributions in three-dimensional problems

    SciTech Connect

    Smith, C.W.

    2000-04-01

    In this paper, an attempt has been made to briefly chart the progress over a period of some 30 years during which the writer and his associates have tried to effect a marriage between the well known, frozen stress method (augmented with the methods of Tardy and Post for refining the near tip fringe analysis), with the principles of fracture mechanics, using an extension of an idea proposed by Irwin. Although a conscious effort was made by the writer to keep the elements of the method as simple as possible so as to allow the application to as broad a range of practical problems as possible while maintaining reasonable engineering accuracy, there were occasional diversions into supporting developments such as the singularity change when a crack intersects a free boundary and the combined use of the stress freezing method with moire. In general, the guidelines employed by the writer included: Use of well established experimental methods; simple algorithms where singularity dominated data zones were revealed by the data itself; applicability to any crack shapes even when unknown apriori; and engineering accuracy of {+-}5% in K{sub 1} in Mode 1 dominated problems.

  10. Experimental results on a wall interference correction method with interface measurements

    NASA Technical Reports Server (NTRS)

    Lo, C. F.; Ulbrich, N.

    1992-01-01

    A wall interference assessment and correction method for subsonic two-dimensional wind tunnel testing is presented. This method calculates a pressure coefficient and angle of attack correction based on velocity measurements on interfaces inside of the wind tunnel. A mathematical representation of the test article is not required. An experimental verification of the suggested technique is given. A NACA 0012 airfoil is tested at a Mach number of 0.70 and at two different angles of attack. Calculated blockage corrections show reasonable agreement with results based on Hackett's method. Corrected surface pressures compare favorably to free-air flow field data if the tunnel flow field is subsonic. The present wall interference correction method can be applied to transonic tunnel flow fields with some restrictions. Errors are estimated and it is shown that the expected error in calculating the pressure coefficient correction on the model surface is in the order of the error of pressure coefficient measurement on interfaces. Necessary testing equipment in existing tunnels can easily be modified if the present method is applied.

  11. Experimental results on a wall interference correction method with interface measurements

    NASA Technical Reports Server (NTRS)

    Lo, C. F.; Ulbrich, N.

    1992-01-01

    A wall interference assessment and correction method for subsonic two-dimensional wind tunnel testing is presented. This method calculates a pressure coefficient and angle of attack correction based on velocity measurements on interfaces inside of the wind tunnel. A mathematical representation of the test article is not required. An experimental verification of the suggested technique is given. A NACA 0012 airfoil is tested at a Mach number of 0.70 and at two different angles of attack. Calculated blockage corrections show reasonable agreement with results based on Hackett's method. Corrected surface pressures compare favorably to free-air flow field data if the tunnel flow field is subsonic. The present wall interference correction method can be applied to transonic tunnel flow fields with some restrictions. Errors are estimated and it is shown that the expected error in calculating the pressure coefficient correction on the model surface is in the order of the error of pressure coefficient measurement on interfaces. Necessary testing equipment in existing tunnels can easily be modified if the present method is applied.

  12. Alternating iterative regression method for dead time estimation from experimental designs.

    PubMed

    Pous-Torres, S; Torres-Lapasió, J R; Baeza-Baeza, J J; García-Alvarez-Coque, M C

    2009-05-01

    An indirect method for dead time (t (0)) estimation in reversed-phase liquid chromatography, based on a relationship between retention time and organic solvent content, is proposed. The method processes the retention data obtained in experimental designs. In order to get more general validity and enhance the accuracy, the information from several compounds is used altogether in an alternating regression fashion. The method was applied to nitrosamines, alkylbenzenes, phenols, benzene derivatives, polycyclic aromatic hydrocarbons and beta-blockers, among other compounds, chromatographed in a cyano and several C18 columns. A comprehensive validation was carried out by comparing the results with those provided by the injection of markers, the observation of the solvent front and the homologous series method. It was also found that different groups of compounds yielded the same t (0) value with the same column, which was verified in different solvent composition windows. The method allows improved models useful for optimisation or for other purposes, since t (0) can be estimated with the retention data of the target solutes.

  13. Experimental Methods for Investigation of Shape Memory Based Elastocaloric Cooling Processes and Model Validation.

    PubMed

    Schmidt, Marvin; Ullrich, Johannes; Wieczorek, André; Frenzel, Jan; Eggeler, Gunther; Schütze, Andreas; Seelecke, Stefan

    2016-05-02

    Shape Memory Alloys (SMA) using elastocaloric cooling processes have the potential to be an environmentally friendly alternative to the conventional vapor compression based cooling process. Nickel-Titanium (Ni-Ti) based alloy systems, especially, show large elastocaloric effects. Furthermore, exhibit large latent heats which is a necessary material property for the development of an efficient solid-state based cooling process. A scientific test rig has been designed to investigate these processes and the elastocaloric effects in SMAs. The realized test rig enables independent control of an SMA's mechanical loading and unloading cycles, as well as conductive heat transfer between SMA cooling elements and a heat source/sink. The test rig is equipped with a comprehensive monitoring system capable of synchronized measurements of mechanical and thermal parameters. In addition to determining the process-dependent mechanical work, the system also enables measurement of thermal caloric aspects of the elastocaloric cooling effect through use of a high-performance infrared camera. This combination is of particular interest, because it allows illustrations of localization and rate effects - both important for efficient heat transfer from the medium to be cooled. The work presented describes an experimental method to identify elastocaloric material properties in different materials and sample geometries. Furthermore, the test rig is used to investigate different cooling process variations. The introduced analysis methods enable a differentiated consideration of material, process and related boundary condition influences on the process efficiency. The comparison of the experimental data with the simulation results (of a thermomechanically coupled finite element model) allows for better understanding of the underlying physics of the elastocaloric effect. In addition, the experimental results, as well as the findings based on the simulation results, are used to improve the

  14. Analytical and experimental methods for adhesively bonded joints subjected to high temperatures

    NASA Astrophysics Data System (ADS)

    Gustafson, Peter A.

    2008-10-01

    Recent advances in material systems have expanded the temperature range over which adhesively bonded composite joints can be used. In this work, several tools are developed for use in modeling joints over a broad range of temperatures. First, a set of dimensionless parameters is established which can be used for analysis of joint performance for an orthotropic symmetric double lap joint. A critical dimensionless ratio of mechanical and thermal loads is identified. The ratio predicts characteristics of the resulting stress distribution. A bonded joint finite element is also developed, wherein a joint-specific finite element is formulated based on an analytical solution. The resulting element allows for mesh-independent joint evaluation and multi-joint simulation at a system or vehicle level. As a mid-level analysis technique, the element has significant predictive and cost advantages over the previously available methods. An advanced analysis technique, the discrete cohesive zone method, is developed and demonstrated in a general element formulation. Initially, the element is examined from the perspective of computational efficiency and robustness. Two efficient traction laws are formulated and are compared to a traction law that is in common use. The element is subsequently used to investigate the interactions of adhesive parameters in standard adhesive characterization experiments. This quantification of experimental sensitivities allows for a deliberate mapping of cumulative experimental results to an appropriate set of model constitutive parameters. With knowledge of the parameter interactions, a set of experimental results are interpreted to determine a set of adhesive constitutive parameters for T650/AFR-PE-4/FM680-1, a high temperature material system of current interest.

  15. An Experimental Method for Measuring Water Droplet Impingement Efficiency on Two- and Three-dimensional Bodies

    NASA Technical Reports Server (NTRS)

    Papadakis, M.; Zumwalt, G. W.; Elangonan, R.; Freund, G. A., Jr.; Breer, M.; Whitmer, L.

    1989-01-01

    An experimental method was developed to determine the droplet impingement characteristics on 2-D and 3-D bodies. The experimental results provide the essential droplet impingement data required to validate water droplet trajectory codes, which are used in the analysis of aircraft icing. A body, whose water droplet impingement characteristics are required, is covered at strategic locations by thin strips of moisture absorbing (blotter) paper, and is exposed to an air stream containing a water dye solution spray cloud. Water droplet impingement data are extracted from the dyed blotter strips by measuring the optical reflectance of the dye deposit on the strips, using an automated reflectometer. Models tested include a 4-inch diameter cylinder, a NACA 652015 airfoil section, a MS(1)-0317 supercritical airfoil section, three simulated ice shapes, an axisymmetric inlet and a Boeing 737-300 inlet model. Detailed descriptions of the dye tracer technique, instrumentation, data reduction method and the results obtained are presented. Analytical predictions of collection efficiency characteristics for most test configurations are included for comparison.

  16. Performance of Higher Order Campbell methods, Part II: calibration and experimental application

    NASA Astrophysics Data System (ADS)

    Elter, Zs.; de Izarra, G.; Filliatre, P.; Jammes, C.; Pázsit, I.

    2016-11-01

    Applying Higher Order Campbelling methods in neutron flux monitoring with fission chambers is advantageous due to their capabilities to suppress the impact of unwanted noises and signal contributions (such as gamma radiation). This work aims to verify through experimental results that the basic assumptions behind the Higher Order Campelling methods are valid in critical reactors. The experiments, reported in this work, were performed at the MINERVE reactor in Cadarache. It is shown that the calibration of a fission chamber and the associated electronic system is possible in higher order mode. With the use of unbiased cumulant estimators and with digital processing, it is shown that over a wide count rate range, accurate count rate estimation can be achieved based on signal samples of a few ms, which is a significant progress compared to similar experimental results in the literature. The difference between the count rate estimated by pulse counting and by the Higher Order Campelling is less than 4%. The work also investigates the possibility of monitoring transient events. For this purpose, a control rod drop event was followed in Higher Order Campbelling mode.

  17. An experimental method to verify soil conservation by check dams on the Loess Plateau, China.

    PubMed

    Xu, X Z; Zhang, H W; Wang, G Q; Chen, S C; Dang, W Q

    2009-12-01

    A successful experiment with a physical model requires necessary conditions of similarity. This study presents an experimental method with a semi-scale physical model. The model is used to monitor and verify soil conservation by check dams in a small watershed on the Loess Plateau of China. During experiments, the model-prototype ratio of geomorphic variables was kept constant under each rainfall event. Consequently, experimental data are available for verification of soil erosion processes in the field and for predicting soil loss in a model watershed with check dams. Thus, it can predict the amount of soil loss in a catchment. This study also mentions four criteria: similarities of watershed geometry, grain size and bare land, Froude number (Fr) for rainfall event, and soil erosion in downscaled models. The efficacy of the proposed method was confirmed using these criteria in two different downscaled model experiments. The B-Model, a large scale model, simulates watershed prototype. The two small scale models, D(a) and D(b), have different erosion rates, but are the same size. These two models simulate hydraulic processes in the B-Model. Experiment results show that while soil loss in the small scale models was converted by multiplying the soil loss scale number, it was very close to that of the B-Model. Obviously, with a semi-scale physical model, experiments are available to verify and predict soil loss in a small watershed area with check dam system on the Loess Plateau, China.

  18. A Wavelet-Based ECG Delineation Method: Adaptation to an Experimental Electrograms with Manifested Global Ischemia.

    PubMed

    Hejč, Jakub; Vítek, Martin; Ronzhina, Marina; Nováková, Marie; Kolářová, Jana

    2015-09-01

    We present a novel wavelet-based ECG delineation method with robust classification of P wave and T wave. The work is aimed on an adaptation of the method to long-term experimental electrograms (EGs) measured on isolated rabbit heart and to evaluate the effect of global ischemia in experimental EGs on delineation performance. The algorithm was tested on a set of 263 rabbit EGs with established reference points and on human signals using standard Common Standards for Quantitative Electrocardiography Standard Database (CSEDB). On CSEDB, standard deviation (SD) of measured errors satisfies given criterions in each point and the results are comparable to other published works. In rabbit signals, our QRS detector reached sensitivity of 99.87% and positive predictivity of 99.89% despite an overlay of spectral components of QRS complex, P wave and power line noise. The algorithm shows great performance in suppressing J-point elevation and reached low overall error in both, QRS onset (SD = 2.8 ms) and QRS offset (SD = 4.3 ms) delineation. T wave offset is detected with acceptable error (SD = 12.9 ms) and sensitivity nearly 99%. Variance of the errors during global ischemia remains relatively stable, however more failures in detection of T wave and P wave occur. Due to differences in spectral and timing characteristics parameters of rabbit based algorithm have to be highly adaptable and set more precisely than in human ECG signals to reach acceptable performance.

  19. Optimal experimental designs for estimating Henry's law constants via the method of phase ratio variation.

    PubMed

    Kapelner, Adam; Krieger, Abba; Blanford, William J

    2016-10-14

    When measuring Henry's law constants (kH) using the phase ratio variation (PRV) method via headspace gas chromatography (GC), the value of kH of the compound under investigation is calculated from the ratio of the slope to the intercept of a linear regression of the inverse GC response versus the ratio of gas to liquid volumes of a series of vials drawn from the same parent solution. Thus, an experimenter collects measurements consisting of the independent variable (the gas/liquid volume ratio) and dependent variable (the GC(-1) peak area). A review of the literature found that the common design is a simple uniform spacing of liquid volumes. We present an optimal experimental design which estimates kH with minimum error and provides multiple means for building confidence intervals for such estimates. We illustrate performance improvements of our design with an example measuring the kH for Naphthalene in aqueous solution as well as simulations on previous studies. Our designs are most applicable after a trial run defines the linear GC response and the linear phase ratio to the GC(-1) region (where the PRV method is suitable) after which a practitioner can collect measurements in bulk. The designs can be easily computed using our open source software optDesignSlopeInt, an R package on CRAN.

  20. Experimental method to characterize the strain dependent permeability of tissue engineering scaffolds.

    PubMed

    Nasrollahzadeh, Naser; Pioletti, Dominique P

    2016-11-07

    Permeability is an overarching mechanical parameter encompassing the effects of porosity, pore size, and interconnectivity of porous structures. This parameter directly influences transport of soluble particles and indirectly regulates fluid pressure and velocity in tissue engineering scaffolds. The permeability also contributes to the viscoelastic behavior of visco-porous material under loading through frictional drag mechanism. We propose a straightforward experimental method for permeability characterization of tissue engineering scaffolds. In the developed set-up a step-wise spacer was designed to facilitate measurement of the permeability under different compressive strains while maintaining similar experimental conditions during the successive measurements. As illustration of the method, we measured the permeability of scaffolds presenting different average pore sizes and subjected to different compression values. Results showed an exponential relationship between the permeability and the average pore size of the scaffolds. Furthermore, the trend of the permeability decrease with compressive strains was depending on pore sizes of the scaffolds. The permeability also appeared to play a role in relaxation behavior of the scaffolds.

  1. Reliability of an experimental method to analyse the impact point on a golf ball during putting.

    PubMed

    Richardson, Ashley K; Mitchell, Andrew C S; Hughes, Gerwyn

    2015-06-01

    This study aimed to examine the reliability of an experimental method identifying the location of the impact point on a golf ball during putting. Forty trials were completed using a mechanical putting robot set to reproduce a putt of 3.2 m, with four different putter-ball combinations. After locating the centre of the dimple pattern (centroid) the following variables were tested; distance of the impact point from the centroid, angle of the impact point from the centroid and distance of the impact point from the centroid derived from the X, Y coordinates. Good to excellent reliability was demonstrated in all impact variables reflected in very strong relative (ICC = 0.98-1.00) and absolute reliability (SEM% = 0.9-4.3%). The highest SEM% observed was 7% for the angle of the impact point from the centroid. In conclusion, the experimental method was shown to be reliable at locating the centroid location of a golf ball, therefore allowing for the identification of the point of impact with the putter head and is suitable for use in subsequent studies.

  2. Designing specific protein-protein interactions using computation, experimental library screening, or integrated methods.

    PubMed

    Chen, T Scott; Keating, Amy E

    2012-07-01

    Given the importance of protein-protein interactions for nearly all biological processes, the design of protein affinity reagents for use in research, diagnosis or therapy is an important endeavor. Engineered proteins would ideally have high specificities for their intended targets, but achieving interaction specificity by design can be challenging. There are two major approaches to protein design or redesign. Most commonly, proteins and peptides are engineered using experimental library screening and/or in vitro evolution. An alternative approach involves using protein structure and computational modeling to rationally choose sequences predicted to have desirable properties. Computational design has successfully produced novel proteins with enhanced stability, desired interactions and enzymatic function. Here we review the strengths and limitations of experimental library screening and computational structure-based design, giving examples where these methods have been applied to designing protein interaction specificity. We highlight recent studies that demonstrate strategies for combining computational modeling with library screening. The computational methods provide focused libraries predicted to be enriched in sequences with the properties of interest. Such integrated approaches represent a promising way to increase the efficiency of protein design and to engineer complex functionality such as interaction specificity.

  3. Experimental methods of indoor millimeter-wave radiometric imaging for personnel concealed contraband detection

    NASA Astrophysics Data System (ADS)

    Hu, Taiyang; Xiao, Zelong; Li, Hao; Lv, Rongchuan; Lu, Xuan

    2014-11-01

    The increasingly emerging terrorism attacks and violence crimes around the world have posed severe threats to public security, so carrying out relevant research on advanced experimental methods of personnel concealed contraband detection is crucial and meaningful. All of the advantages of imaging covertly, avoidance of interference with other systems, intrinsic property of being safe to persons under screening , and the superior ability of imaging through natural or manmade obscurants, have significantly combined to enable millimeter-wave (MMW) radiometric imaging to offer great potential in personnel concealed contraband detection. Based upon the current research status of MMW radiometric imaging and urgent demands of personnel security screening, this paper mainly focuses on the experimental methods of indoor MMW radiometric imaging. The reverse radiation noise resulting from super-heterodyne receivers seriously affects the image experiments carried out at short range, so both the generation mechanism and reducing methods of this noise are investigated. Then, the benefit of sky illumination no longer exists for the indoor radiometric imaging, and this leads to the decrease in radiometric temperature contrast between target and background. In order to enhance the radiometric temperature contrast for improving indoor imaging performance, the noise illumination technique is adopted in the indoor imaging scenario. In addition, the speed and accuracy of concealed contraband detection from acquired MMW radiometric images are usually restricted to the deficiencies in traditional artificial interpretation by security inspectors, thus an automatic recognition and location algorithm by integrating improved Fuzzy C-means clustering with moment invariants is put forward. A series of original results are also presented to demonstrate the significance and validity of these methods.

  4. Landmarks in nature to support wayfinding: the effects of seasons and experimental methods.

    PubMed

    Kettunen, Pyry; Irvankoski, Katja; Krause, Christina M; Sarjakoski, L Tiina

    2013-08-01

    Landmarks constitute an essential basis for a structural understanding of the spatial environment. Therefore, they are crucial factors in external spatial representations such as maps and verbal route descriptions, which are used to support wayfinding. However, selecting landmarks for these representations is a difficult task, for which an understanding of how people perceive and remember landmarks in the environment is needed. We investigated the ways in which people perceive and remember landmarks in nature using the thinking aloud and sketch map methods during both the summer and the winter seasons. We examined the differences between methods to identify those landmarks that should be selected for external spatial representations, such as maps or route descriptions, in varying conditions. We found differences in the use of landmarks both in terms of the methods and also between the different seasons. In particular, the participants used passage and tree-related landmarks at significantly different frequencies with the thinking aloud and sketch map methods. The results are likely to reflect the different roles of the landmark groups when using the two methods, but also the differences in counting landmarks when using both methods. Seasonal differences in the use of landmarks occurred only with the thinking aloud method. Sketch maps were drawn similarly in summertime and wintertime; the participants remembered and selected landmarks similarly independent of the differences in their perceptions of the environment due to the season. The achieved results may guide the planning of external spatial representations within the context of wayfinding as well as when planning further experimental studies.

  5. REVIEW: A review of in vivo experimental methods to determine the composition of the human body

    NASA Astrophysics Data System (ADS)

    Sutcliffe, J. F.

    1996-05-01

    This review of experimental methods employed in the measurement of the composition of the human body covers the developments that have occurred over the past 30 years. Early methods such as hydrodensitometry and skinfold anthropometry have been superseded by dual-energy x-ray absorptiometry and bioelectrical impedance spectroscopy. The measurement of the whole-body abundance of certain elements by isotopic dilution, neutron activation analysis and x-ray fluorescence can give important information of clinical significance, but neutron activation facilities remain available in only a few centres worldwide. The relatively simple, rapid and risk-free electrical methods such as multifrequency bioelectrical impedance analysis, which can be employed at the bedside, have been found to be more complicated in their interpretation. Electromagnetic methods may only measure the composition of the human body at its surface. X-ray computed tomography and magnetic resonance imaging have not yet been employed much in body composition measurements. Some models for the composition of the human body are reviewed.

  6. Using machine learning methods to predict experimental high-throughput screening data.

    PubMed

    Mballo, Chérif; Makarenkov, Vladimir

    2010-06-01

    High-throughput screening (HTS) remains a very costly process notwithstanding many recent technological advances in the field of biotechnology. In this study we consider the application of machine learning methods for predicting experimental HTS measurements. Such a virtual HTS analysis can be based on the results of real HTS campaigns carried out with similar compounds libraries and similar drug targets. In this way, we analyzed Test assay from McMaster University Data Mining and Docking Competition using binary decision trees, neural networks, support vector machines (SVM), linear discriminant analysis, k-nearest neighbors and partial least squares. First, we studied separately the sets of molecular and atomic descriptors in order to establish which of them provides a better prediction. Then, the comparison of the six considered machine learning methods was made in terms of false positives and false negatives, method's sensitivity and enrichment factor. Finally, a variable selection procedure allowing one to improve the method's sensitivity was implemented and applied in the framework of polynomial SVM.

  7. Isolated Liver Perfusion Using Percutaneous Methods:[ql An Experimental Study in the Pig

    SciTech Connect

    Harnek, Jan; Cwikiel, Wojciech; Bergqvist, Lennart; Persson, Bo; Stridbeck, Hans

    1996-11-15

    Purpose: To develop a method for isolated perfusion of the liver using radiological methods. Methods: Twenty-one pigs, weighing about 20 kg, were divided into three groups. By transjugular and transfemoral approaches two occlusion balloons were placed in the inferior vena cava cranial and caudal, respectively, to the origin of the hepatic veins. One occlusion balloon was placed transfemorally in the common hepatic artery. Another occlusion balloon was inserted in the main branch of the portal vein via the transjugular-transhepatic approach in 11 pigs (groups 1 and 2), and in 10 pigs (group 3) by a percutaneous transhepatic route. After inflation of the balloons, patency of the isolated liver circulation was evaluated by recirculation of {sup 99}Tc{sup m}-labelled human albumin during 30 min. Blood tests were obtained after 1, 3, 5, 10, 15, and 30 min to evaluate leakage from the liver to the systemic circulation. Results: Increasing leakage to the systemic circulation from the isolated liver circulation was observed in groups 1 and 2. In the third group the leakage was less than 10%. Conclusion: In an experimental animal model, isolated perfusion of the liver with minor leakage to the systemic circulation may be achieved using radiological methods.

  8. Ensemble-Biased Metadynamics: A Molecular Simulation Method to Sample Experimental Distributions.

    PubMed

    Marinelli, Fabrizio; Faraldo-Gómez, José D

    2015-06-16

    We introduce an enhanced-sampling method for molecular dynamics (MD) simulations referred to as ensemble-biased metadynamics (EBMetaD). The method biases a conventional MD simulation to sample a molecular ensemble that is consistent with one or more probability distributions known a priori, e.g., experimental intramolecular distance distributions obtained by double electron-electron resonance or other spectroscopic techniques. To this end, EBMetaD adds an adaptive biasing potential throughout the simulation that discourages sampling of configurations inconsistent with the target probability distributions. The bias introduced is the minimum necessary to fulfill the target distributions, i.e., EBMetaD satisfies the maximum-entropy principle. Unlike other methods, EBMetaD does not require multiple simulation replicas or the introduction of Lagrange multipliers, and is therefore computationally efficient and straightforward in practice. We demonstrate the performance and accuracy of the method for a model system as well as for spin-labeled T4 lysozyme in explicit water, and show how EBMetaD reproduces three double electron-electron resonance distance distributions concurrently within a few tens of nanoseconds of simulation time. EBMetaD is integrated in the open-source PLUMED plug-in (www.plumed-code.org), and can be therefore readily used with multiple MD engines.

  9. A new method in the treatment of ear amputation: experimental and clinical study.

    PubMed

    Alagöz, M Sahin; Uysal, A Cağr; Işgören, Serkan; Erdoğan, Cüneyt; Işken, Tonguç; Sen, Cenk; Tüccar, Eray; Sabuncuoğlu, Bizden Tavl; Sensöz, Omer

    2007-09-01

    There have been plenty of reconstruction methods for ear amputation, and replantation preserves its importance. In situations where replantation is not feasible, various methods were proposed. We indicate an alternative technique for the ear amputation without replantation indication. The method of replacing of a vascular structure into the tunnel formed on the posterior side of the amputated ear was used instead of replacing the ear cartilage into a vascular area that was described in the literature of ear prefabrication. The dorsal fascial flaps which were prepared from the back of 10 New Zealand rabbits were placed into the amputated ear. The 2 groups, control and the experimental, were consequently the ear that was adapted as a composite graft and the ear with the flap inserted. The ears were examined macroscopically and photographed on postoperative days 3, 7, 14, and 21. On the 21st day, the nourishment pattern of the ear, the dorsal fascia, and the dorsal fascia adapted ear were investigated with digital subtraction angiography (DSA). The group that received applied dorsal fascia possessed increased vascularity. The viability was evaluated with the biopsies taken from the control group and the group that received applied dorsal fascial flap on the 21st day. The cartilage and the connective tissue were viable in the flap-applied group, whereas there was necrosis in the control group. The reflection of the experimental study was performed on 2 subtotal and 1 total ear amputation cases, with the utilization of the superficial temporal artery. The nourishment of the flaps was evaluated with postoperative photographs, angiography, and bone scintigraphy.

  10. A Direct Method for Incorporating Experimental Data into Multiscale Coarse-Grained Models.

    PubMed

    Dannenhoffer-Lafage, Thomas; White, Andrew D; Voth, Gregory A

    2016-05-10

    To extract meaningful data from molecular simulations, it is necessary to incorporate new experimental observations as they become available. Recently, a new method was developed for incorporating experimental observations into molecular simulations, called experiment directed simulation (EDS), which utilizes a maximum entropy argument to bias an existing model to agree with experimental observations while changing the original model by a minimal amount. However, there is no discussion in the literature of whether or not the minimal bias systematically and generally improves the model by creating agreement with the experiment. In this work, we show that the relative entropy of the biased system with respect to an ideal target is always reduced by the application of a minimal bias, such as the one utilized by EDS. Using all-atom simulations that have been biased with EDS, one can then easily and rapidly improve a bottom-up multiscale coarse-grained (MS-CG) model without the need for a time-consuming reparametrization of the underlying atomistic force field. Furthermore, the improvement given by the many-body interactions introduced by the EDS bias can be maintained after being projected down to effective two-body MS-CG interactions. The result of this analysis is a new paradigm in coarse-grained modeling and simulation in which the "bottom-up" and "top-down" approaches are combined within a single, rigorous formalism based on statistical mechanics. The utility of building the resulting EDS-MS-CG models is demonstrated on two molecular systems: liquid methanol and ethylene carbonate.

  11. Stacking Interactions between Carbohydrate and Protein Quantified by Combination of Theoretical and Experimental Methods

    PubMed Central

    Nečasová, Ivona; Mishra, Sushil Kumar; Komárek, Jan; Koča, Jaroslav

    2012-01-01

    Carbohydrate – receptor interactions are an integral part of biological events. They play an important role in many cellular processes, such as cell-cell adhesion, cell differentiation and in-cell signaling. Carbohydrates can interact with a receptor by using several types of intermolecular interactions. One of the most important is the interaction of a carbohydrate's apolar part with aromatic amino acid residues, known as dispersion interaction or CH/π interaction. In the study presented here, we attempted for the first time to quantify how the CH/π interaction contributes to a more general carbohydrate - protein interaction. We used a combined experimental approach, creating single and double point mutants with high level computational methods, and applied both to Ralstonia solanacearum (RSL) lectin complexes with α-l-Me-fucoside. Experimentally measured binding affinities were compared with computed carbohydrate-aromatic amino acid residue interaction energies. Experimental binding affinities for the RSL wild type, phenylalanine and alanine mutants were −8.5, −7.1 and −4.1 kcal.mol−1, respectively. These affinities agree with the computed dispersion interaction energy between carbohydrate and aromatic amino acid residues for RSL wild type and phenylalanine, with values −8.8, −7.9 kcal.mol−1, excluding the alanine mutant where the interaction energy was −0.9 kcal.mol−1. Molecular dynamics simulations show that discrepancy can be caused by creation of a new hydrogen bond between the α-l-Me-fucoside and RSL. Observed results suggest that in this and similar cases the carbohydrate-receptor interaction can be driven mainly by a dispersion interaction. PMID:23056230

  12. DETECTORS AND EXPERIMENTAL METHODS: An artificial neural network for proton identification in HERMES data

    NASA Astrophysics Data System (ADS)

    Wang, Si-Guang; Mao, Ya-Jun; Ye, Hong-Xue

    2009-03-01

    The HERMES time-of-flight (TOF) system is used for proton identification, but must be carefully calibrated for systematic biases in the equipment. This paper presents an artificial neural network (ANN) trained to recognize protons from Λ° decay using only raw event data such as time delay, momentum, and trajectory. To avoid the systematic errors associated with Monte Carlo models, we collect a sample of raw experimental data from the year 2000. We presume that when for a positive hadron (assigned one proton mass) and a negative hadron (assigned one π- mass) the reconstructed invariant mass lies within the Λ° resonance, the positive hadron is more likely to be a proton. Such events are assigned an output value of one during the training process; all others were assigned the output value zero. The trained ANN is capable of identifying protons in independent experimental data, with an efficiency equivalent to the traditional TOF calibration. By modifying the threshold for proton identification, a researcher can trade off between selection efficiency and background rejection power. This simple and convenient method is applicable to similar detection problems in other experiments.

  13. Microbiota of Soil-Like Substrate Depending on Wheat Straw Processing Method in Experimental LSS Model

    NASA Astrophysics Data System (ADS)

    Tirranen, Lyalya; Sysoeva, Olga

    In previous experiments conducted in the closed environmental system BIOS-3 plant waste and test persons' exometabolites were carried away from the life-support system (LSS). It is possible to create a new-generation LSS with a higher degree of matter cycle closure by adding to the soil-like substrate inedible plant waste used for cultivation of plants in the experimental LSS model. Using single-factor analysis of variance, we estimated the effect of the introduced inedible plant waste on the microbiota of the soil-like substrate (SLS). The plant waste was used: to increase the degree of matter cycle closure in the system; to replace the volume of soil-like substrate in the system; as a fertilizer for growing higher plants in the experimental LSS model. A statistically significant effect of wheat straw processing method on the number of all microorganism groups was observed in different variants of the experiment. The obtained results can be used in planning and carrying out of subsequent experiments with higher plants cultivated on SLS with waste in a closed environmental system including humans.

  14. Integration of experimental and computational methods for identifying geometric, thermal and diffusive properties of biomaterials

    NASA Astrophysics Data System (ADS)

    Weres, Jerzy; Kujawa, Sebastian; Olek, Wiesław; Czajkowski, Łukasz

    2016-04-01

    Knowledge of physical properties of biomaterials is important in understanding and designing agri-food and wood processing industries. In the study presented in this paper computational methods were developed and combined with experiments to enhance identification of agri-food and forest product properties, and to predict heat and water transport in such products. They were based on the finite element model of heat and water transport and supplemented with experimental data. Algorithms were proposed for image processing, geometry meshing, and inverse/direct finite element modelling. The resulting software system was composed of integrated subsystems for 3D geometry data acquisition and mesh generation, for 3D geometry modelling and visualization, and for inverse/direct problem computations for the heat and water transport processes. Auxiliary packages were developed to assess performance, accuracy and unification of data access. The software was validated by identifying selected properties and using the estimated values to predict the examined processes, and then comparing predictions to experimental data. The geometry, thermal conductivity, specific heat, coefficient of water diffusion, equilibrium water content and convective heat and water transfer coefficients in the boundary layer were analysed. The estimated values, used as an input for simulation of the examined processes, enabled reduction in the uncertainty associated with predictions.

  15. Experimental and theoretical analysis of a method to predict thermal runaway in Li-ion cells

    NASA Astrophysics Data System (ADS)

    Shah, Krishna; Chalise, Divya; Jain, Ankur

    2016-10-01

    Thermal runaway is a well-known safety concern in Li-ion cells. Methods to predict and prevent thermal runaway are critically needed for enhanced safety and performance. While much work has been done on understanding the kinetics of various heat generation processes during thermal runaway, relatively lesser work exists on understanding how heat removal from the cell influences thermal runaway. Through a unified analysis of heat generation and heat removal, this paper derives and experimentally validates a non-dimensional parameter whose value governs whether or not thermal runaway will occur in a Li-ion cell. This parameter is named the Thermal Runaway Number (TRN), and comprises contributions from thermal transport within and outside the cell, as well as the temperature dependence of heat generation rate. Experimental data using a 26650 thermal test cell are in good agreement with the model, and demonstrate the dependence of thermal runaway on various thermal transport and heat generation parameters. This parameter is used to predict the thermal design space in which the cell will or will not experience thermal runaway. By combining all thermal processes contributing to thermal runaway in a single parameter, this work contributes towards a unified understanding of thermal runaway, and provides the fundamental basis for design tools for safe, high-performance Li-ion batteries.

  16. Validation of RF CCP Discharge Model against Experimental Data using PIC Method

    NASA Astrophysics Data System (ADS)

    Icenhour, Casey; Kummerer, Theresa; Green, David L.; Smithe, David; Shannon, Steven

    2014-10-01

    The particle-in-cell (PIC) simulation method is a well-known standard for the simulation of laboratory plasma discharges. Using parallel computation on the Titan supercomputer at Oak Ridge National Laboratory (ORNL), this research is concerned with validation of a radio-frequency (RF) capacitively-coupled plasma (CCP) discharge PIC model against previously obtained experimental data. The plasma sources under simulation are 10--100 mTorr argon plasmas with a 13 MHz source and 27 MHz source operating at 50--200 W in both pulse and constant power conditions. Plasma parameters of interest in the validation include peak electron density, electron temperature, and RF plasma sheath voltages and thicknesses. The plasma is modeled utilizing the VSim plasma simulation tool, developed by the Tech-X Corporation. The implementation used here is a two-dimensional electromagnetic model, with corresponding external circuit model of the experimental setup. The goal of this study is to develop models for more complex RF plasma systems utilizing highly parallel computing technologies and methodology. This work is carried out with the support of Oak Ridge National Laboratory and the Tech-X Corporation.

  17. Spatial memory: Theoretical basis and comparative review on experimental methods in rodents.

    PubMed

    Paul, Carrillo-Mora; Magda, Giordano; Abel, Santamaría

    2009-11-05

    The assessment of learning and memory in animal models has been widely employed in scientific research for a long time. Among these models, those representing diseases with primary processes of affected memory - such as amnesia, dementia, brain aging, etc. - studies dealing with the toxic effects of specific drugs, and other exploring neurodevelopment, trauma, epilepsy and neuropsychiatric disorders, are often called on to employ these tools. There is a diversity of experimental methods assessing animal learning and memory skills. Overall, mazes are the devices mostly used today to test memory in rodents; there are several types of them, but their real usefulness, advantages and applications remain to be fully established and depend on the particular variant selected by the experimenter. The aims of the present article are first, to briefly review the accumulated knowledge in regard to spatial memory tasks; second, to bring the reader information on the different types of rodent mazes available to test spatial memory; and third, to elucidate the usefulness and limitations of each of these devices.

  18. Theoretical model and experimental verification on the PID tracking method using liquid crystal optical phased array

    NASA Astrophysics Data System (ADS)

    Wang, Xiangru; Xu, Jianhua; Huang, Ziqiang; Wu, Liang; Zhang, Tianyi; Wu, Shuanghong; Qiu, Qi

    2017-02-01

    Liquid crystal optical phased array (LC-OPA) has been considered with great potential on the non-mechanical laser deflector because it is fabricated using photolithographic patterning technology which has been well advanced by the electronics and display industry. As a vital application of LC-OPA, free space laser communication has demonstrated its merits on communication bandwidth. Before data communication, ATP (acquisition, tracking and pointing) process costs relatively long time to result in a bottle-neck of free space laser communication. Meanwhile, dynamic real time accurate tracking is sensitive to keep a stable communication link. The electro-optic medium liquid crystal with low driving voltage can be used as the laser beam deflector. This paper presents a fast-track method using liquid crystal optical phased array as the beam deflector, CCD as a beacon light detector. PID (Proportion Integration Differentiation) loop algorithm is introduced as the controlling algorithm to generate the corresponding steering angle. To achieve the goal of fast and accurate tracking, theoretical analysis and experimental verification are demonstrated that PID closed-loop system can suppress the attitude random vibration. Meanwhile, theoretical analysis shows that tracking accuracy can be less than 6.5μrad, with a relative agreement with experimental results which is obtained after 10 adjustments that the tracking accuracy is less than12.6μrad.

  19. Marine Mammal Train Oil Production Methods: Experimental Reconstructions of Norwegian Iron Age Slab-Lined Pits

    NASA Astrophysics Data System (ADS)

    Nilsen, Gørill

    2016-08-01

    Seal hunting and whaling have played an important part of people's livelihoods throughout prehistory as evidenced by rock carvings, remains of bones, artifacts from aquatic animals and hunting tools. This paper focuses on one of the more elusive resources relating to such activities: marine mammal blubber. Although marine blubber easily decomposes, the organic material has been documented from the Mesolithic Period onwards. Of particular interest in this article are the many structures in Northern Norway from the Iron Age and in Finland on Kökar, Åland, from both the Bronze and Early Iron Ages in which these periods exhibited traits interpreted as being related to oil rendering from marine mammal blubber. The article discusses methods used in this oil production activity based on historical sources, archaeological investigations and experimental reconstruction of Iron Age slab-lined pits from Northern Norway.

  20. Contaminated water delivery as a simple and effective method of experimental Salmonella infection

    PubMed Central

    O’Donnell, Hope; Pham, Oanh H.; Benoun, Joseph M.; Ravesloot-Chávez, Marietta M.; McSorley, Stephen J.

    2016-01-01

    Aims In most infectious disease models, it is assumed that gavage needle infection is the most reliable means of pathogen delivery to the gastrointestinal tract. However, this methodology can cause esophageal tearing and induces stress in experimental animals, both of which have the potential to impact early infection and the subsequent immune response. Materials and Methods C57BL/6 mice were orally infected with virulent Salmonella Typhimurium SL1344 either by intragastric gavage preceded by sodium bicarbonate, or by contamination of drinking water. Results We demonstrate that water contamination delivery of Salmonella is equivalent to gavage inoculation in providing a consistent model of infection. Furthermore, exposure of mice to contaminated drinking water for as little as 4 hours allowed maximal mucosal and systemic infection, suggesting an abbreviated window exists for natural intestinal entry. Conclusions Together, these data question the need for gavage delivery for infection with oral pathogens. PMID:26439708

  1. Use of experimental data in testing methods for design against uncertainty

    NASA Astrophysics Data System (ADS)

    Rosca, Raluca Ioana

    Modern methods of design take into consideration the fact that uncertainty is present in everyday life, whether in the form of variable loads (the strongest wind that would affect a building), material properties of an alloy, or future demand for the product or cost of labor. Moreover, the Japanese example showed that it may be more cost-effective to design taking into account the existence of the uncertainty rather than to plan to eliminate or greatly reduce it. The dissertation starts by comparing the theoretical basis of two methods for design against uncertainty, namely probability theory and possibility theory. A two-variable design problem is then used to show the differences. It is concluded that for design problems with two or more cases of failure of very different magnitude (as the stop of a car due to lack of gas or motor failure), probability theory divides existent resources in a more intuitive way than possibility theory. The dissertation continues with the description of simple experiments (building towers of dominoes) and then it presents the methodology to increase the amount of information that can be drawn from a given data set. The methodology is shown on the Bidder-Challenger problem, a simulation of a problem of a company that makes microchips to set a target speed for its next microchip. The simulations use the domino experimental data. It is demonstrated that important insights into methods of probability and possibility based design can be gained from experiments.

  2. Theoretical and experimental study of a new method for prediction of profile drag of airfoil sections

    NASA Technical Reports Server (NTRS)

    Goradia, S. H.; Lilley, D. E.

    1975-01-01

    Theoretical and experimental studies are described which were conducted for the purpose of developing a new generalized method for the prediction of profile drag of single component airfoil sections with sharp trailing edges. This method aims at solution for the flow in the wake from the airfoil trailing edge to the large distance in the downstream direction; the profile drag of the given airfoil section can then easily be obtained from the momentum balance once the shape of velocity profile at a large distance from the airfoil trailing edge has been computed. Computer program subroutines have been developed for the computation of the profile drag and flow in the airfoil wake on CDC6600 computer. The required inputs to the computer program consist of free stream conditions and the characteristics of the boundary layers at the airfoil trailing edge or at the point of incipient separation in the neighborhood of airfoil trailing edge. The method described is quite generalized and hence can be extended to the solution of the profile drag for multi-component airfoil sections.

  3. Experimental Method for Determination of Self-Heating at the Point of Measurement

    NASA Astrophysics Data System (ADS)

    Sestan, D.; Zvizdic, D.; Grgec-Bermanec, L.

    2017-09-01

    This paper presents a new experimental method and algorithm for the determination of self-heating of platinum resistance thermometer (PRT) when the temperature instability of medium of interest would prevent an accurate self-heating determination using standard methods. In temperature measurements performed by PRT, self-heating is one of the most common sources of error and arises from the increase in sensor temperature caused by the dissipation of electrical heat when measurement current is applied to the temperature sensing element. This increase depends mainly on the applied current and the thermal resistances between thermometer sensing element and the environment surrounding the thermometer. The method is used for determination of self-heating of a 100 Ω industrial PRT which is intended for measurement of air temperature inside the saturation chamber of the primary dew/frost point generator at the Laboratory for Process Measurement (HMI/FSB-LPM). Self-heating is first determined for conditions present during the comparison calibration of the thermometer, using the calibration bath. The measurements were then repeated with thermometer being placed in an air stream inside the saturation chamber. The experiment covers the temperature range between -65°C and 10°C. Self-heating is determined for two different air velocities and two different vertical positions of PRT in relation to the chamber bottom.

  4. Simple experimental method for alpha particle range determination in lead iodide films

    SciTech Connect

    Dmitriev, Yuri; Bennett, Paul R.; Cirignano, Leonard J.; Klugerman, Mikhail; Shah, Kanai S.

    2007-05-15

    An experimental method for determining the range of alpha particles in films based on I-V{sub s} analysis has been suggested. The range of 5.5 MeV alpha particles in PbI{sub 2} films determined by this technique is 30{+-}5 {mu}m, and this value is in agreement with the value calculated by SRIM (the stopping and range of ions in matter), r=24 {mu}m in PbI{sub 2}. More than 100 I-V{sub s} of PbI{sub 2} films with different thicknesses and quality have been analyzed, and the influence of alpha particle radiation on PbI{sub 2} I-V{sub s} curves has been studied. Developed analytical methods (dependence of current density on electric field and conception of surface defects) were used, and the method limitations are discussed. It was shown that I-V{sub s} demonstrate the tendency to obey Ohm's law under alpha radiation. On the other hand, dark conductivity of the lead iodide films shows a typical impure character that can lead to an overestimation of the alpha particles' range in PbI{sub 2} films. After films were exposed to alpha radiation, the dark resistivity and I-V shape of some films improved. Also, a weak decrease of the charge carrier concentration, due to a decrease of the ''surface defect'' concentration (''surface refining''), was registered after successive measurements of I-V{sub s}.

  5. A New Wavelet Denoising Method for Experimental Time-Domain Signals: Pulsed Dipolar Electron Spin Resonance.

    PubMed

    Srivastava, Madhur; Georgieva, Elka R; Freed, Jack H

    2017-03-30

    We adapt a new wavelet-transform-based method of denoising experimental signals to pulse-dipolar electron-spin resonance spectroscopy (PDS). We show that signal averaging times of the time-domain signals can be reduced by as much as 2 orders of magnitude, while retaining the fidelity of the underlying signals, in comparison with noiseless reference signals. We have achieved excellent signal recovery when the initial noisy signal has an SNR ≳ 3. This approach is robust and is expected to be applicable to other time-domain spectroscopies. In PDS, these time-domain signals representing the dipolar interaction between two electron spin labels are converted into their distance distribution functions P(r), usually by regularization methods such as Tikhonov regularization. The significant improvements achieved by using denoised signals for this regularization are described. We show that they yield P(r)'s with more accurate detail and yield clearer separations of respective distances, which is especially important when the P(r)'s are complex. Also, longer distance P(r)'s, requiring longer dipolar evolution times, become accessible after denoising. In comparison to standard wavelet denoising approaches, it is clearly shown that the new method (WavPDS) is superior.

  6. On the reliability of HELIOSAT method: A comparison with experimental data

    SciTech Connect

    Guemene Dountio, E.; Njomo, D.; Fouda, Efa; Simo, A.

    2010-06-15

    This study deals with comparison of Cameroonian ground based measurements with estimations done using satellite images, by applying the second version of the HELIOSAT method, as computed by the web tool HELIOCLIM of the SoDa project. Measurements and satellite resources were chosen for the same period of the year 1985, on ten Cameroonian locations, distributed with mean spatial resolution of 200 km between two neighbouring stations. Correlations curves are constructed between daily irradiation estimates from satellite data and from measurements. The consequent regression equations are established, using the least square method. Finally, a brief discussion is carried out on the spatial distribution of errors observed on results. Similarly to previous studies this study confirmed the capability of the method to produce good results for the Garoua location, and established its extension on other sahelian sites, comparatively to the poor agreement observed on southern sites. Furthermore, even if the study was not done on a long period, it brought out the necessity to correct the HELIOSAT results for many Cameroonian locations, to march the experimental results. (author)

  7. An experimental validation method for questioning techniques that assess sensitive issues.

    PubMed

    Moshagen, Morten; Hilbig, Benjamin E; Erdfelder, Edgar; Moritz, Annie

    2014-01-01

    Studies addressing sensitive issues often yield distorted prevalence estimates due to socially desirable responding. Several techniques have been proposed to reduce this bias, including indirect questioning, psychophysiological lie detection, and bogus pipeline procedures. However, the increase in resources required by these techniques is warranted only if there is a substantial increase in validity as compared to direct questions. Convincing demonstration of superior validity necessitates the availability of a criterion reflecting the "true" prevalence of a sensitive attribute. Unfortunately, such criteria are notoriously difficult to obtain, which is why validation studies often proceed indirectly by simply comparing estimates obtained with different methods. Comparative validation studies, however, provide weak evidence only since the exact increase in validity (if any) remains unknown. To remedy this problem, we propose a simple method that allows for measuring the "true" prevalence of a sensitive behavior experimentally. The basic idea is to elicit normatively problematic behavior in a way that ensures conclusive knowledge of the prevalence rate of this behavior. This prevalence measure can then serve as an external validation criterion in a second step. An empirical demonstration of this method is provided.

  8. Learning from our GWAS mistakes: from experimental design to scientific method.

    PubMed

    Lambert, Christophe G; Black, Laura J

    2012-04-01

    Many public and private genome-wide association studies that we have analyzed include flaws in design, with avoidable confounding appearing as a norm rather than the exception. Rather than recognizing flawed research design and addressing that, a category of quality-control statistical methods has arisen to treat only the symptoms. Reflecting more deeply, we examine elements of current genomic research in light of the traditional scientific method and find that hypotheses are often detached from data collection, experimental design, and causal theories. Association studies independent of causal theories, along with multiple testing errors, too often drive health care and public policy decisions. In an era of large-scale biological research, we ask questions about the role of statistical analyses in advancing coherent theories of diseases and their mechanisms. We advocate for reinterpretation of the scientific method in the context of large-scale data analysis opportunities and for renewed appreciation of falsifiable hypotheses, so that we can learn more from our best mistakes.

  9. An experimental study of rill sediment delivery in purple soil, using the volume-replacement method

    PubMed Central

    Huang, Yuhan; Luo, Banglin; Ding, Linqiao; Gong, Chunming

    2015-01-01

    Experimental studies provide a basis for understanding the mechanisms of rill erosion and can provide estimates for parameter values in physical models simulating the erosion process. In this study, we investigated sediment delivery during rill erosion in purple soil. We used the volume-replacement method to measure the volume of eroded soil and hence estimate the mass of eroded soil. A 12 m artificial rill was divided into the following sections: 0–0.5 m, 0.5–1 m, 1–2 m, 2–3 m, 3–4 m, 4–5 m, 5–6 m, 6–7 m, 7–8 m, 8–10 m, and 10–12 m. Erosion trials were conducted with three flow rates (2 L/min, 4 L/min, and 8 L/min) and five slope gradients (5°, 10°, 15°, 20°, and 25°). The eroded rill sections were refilled with water to measure the eroded volume in each section and subsequently calculate the eroded sediment mass. The cumulative sediment mass was used to compute the sediment concentration along the length of the rill. The results show that purple soil sediment concentration increases with rill length before eventually reaching a maximal value; that is, the rate of increase in sediment concentration is greatest at the rill inlet and then gradually slows. Steeper slopes and higher flow rates result in sediment concentration increasing more rapidly along the rill length and the maximum sediment concentration being reached at an earlier location in the rill. Slope gradient and flow rate both result in an increase in maximal sediment concentration and accumulated eroded amount. However, slope gradient has a greater influence on rill erosion than flow rate. The results and experimental method in this study may provide a reference for future rill-erosion experiments. PMID:26734498

  10. Inferring Regulatory Networks from Experimental Morphological Phenotypes: A Computational Method Reverse-Engineers Planarian Regeneration

    PubMed Central

    Lobo, Daniel; Levin, Michael

    2015-01-01

    Transformative applications in biomedicine require the discovery of complex regulatory networks that explain the development and regeneration of anatomical structures, and reveal what external signals will trigger desired changes of large-scale pattern. Despite recent advances in bioinformatics, extracting mechanistic pathway models from experimental morphological data is a key open challenge that has resisted automation. The fundamental difficulty of manually predicting emergent behavior of even simple networks has limited the models invented by human scientists to pathway diagrams that show necessary subunit interactions but do not reveal the dynamics that are sufficient for complex, self-regulating pattern to emerge. To finally bridge the gap between high-resolution genetic data and the ability to understand and control patterning, it is critical to develop computational tools to efficiently extract regulatory pathways from the resultant experimental shape phenotypes. For example, planarian regeneration has been studied for over a century, but despite increasing insight into the pathways that control its stem cells, no constructive, mechanistic model has yet been found by human scientists that explains more than one or two key features of its remarkable ability to regenerate its correct anatomical pattern after drastic perturbations. We present a method to infer the molecular products, topology, and spatial and temporal non-linear dynamics of regulatory networks recapitulating in silico the rich dataset of morphological phenotypes resulting from genetic, surgical, and pharmacological experiments. We demonstrated our approach by inferring complete regulatory networks explaining the outcomes of the main functional regeneration experiments in the planarian literature; By analyzing all the datasets together, our system inferred the first systems-biology comprehensive dynamical model explaining patterning in planarian regeneration. This method provides an automated

  11. An experimental study of rill sediment delivery in purple soil, using the volume-replacement method.

    PubMed

    Huang, Yuhan; Chen, Xiaoyan; Luo, Banglin; Ding, Linqiao; Gong, Chunming

    2015-01-01

    Experimental studies provide a basis for understanding the mechanisms of rill erosion and can provide estimates for parameter values in physical models simulating the erosion process. In this study, we investigated sediment delivery during rill erosion in purple soil. We used the volume-replacement method to measure the volume of eroded soil and hence estimate the mass of eroded soil. A 12 m artificial rill was divided into the following sections: 0-0.5 m, 0.5-1 m, 1-2 m, 2-3 m, 3-4 m, 4-5 m, 5-6 m, 6-7 m, 7-8 m, 8-10 m, and 10-12 m. Erosion trials were conducted with three flow rates (2 L/min, 4 L/min, and 8 L/min) and five slope gradients (5°, 10°, 15°, 20°, and 25°). The eroded rill sections were refilled with water to measure the eroded volume in each section and subsequently calculate the eroded sediment mass. The cumulative sediment mass was used to compute the sediment concentration along the length of the rill. The results show that purple soil sediment concentration increases with rill length before eventually reaching a maximal value; that is, the rate of increase in sediment concentration is greatest at the rill inlet and then gradually slows. Steeper slopes and higher flow rates result in sediment concentration increasing more rapidly along the rill length and the maximum sediment concentration being reached at an earlier location in the rill. Slope gradient and flow rate both result in an increase in maximal sediment concentration and accumulated eroded amount. However, slope gradient has a greater influence on rill erosion than flow rate. The results and experimental method in this study may provide a reference for future rill-erosion experiments.

  12. Inferring regulatory networks from experimental morphological phenotypes: a computational method reverse-engineers planarian regeneration.

    PubMed

    Lobo, Daniel; Levin, Michael

    2015-06-01

    Transformative applications in biomedicine require the discovery of complex regulatory networks that explain the development and regeneration of anatomical structures, and reveal what external signals will trigger desired changes of large-scale pattern. Despite recent advances in bioinformatics, extracting mechanistic pathway models from experimental morphological data is a key open challenge that has resisted automation. The fundamental difficulty of manually predicting emergent behavior of even simple networks has limited the models invented by human scientists to pathway diagrams that show necessary subunit interactions but do not reveal the dynamics that are sufficient for complex, self-regulating pattern to emerge. To finally bridge the gap between high-resolution genetic data and the ability to understand and control patterning, it is critical to develop computational tools to efficiently extract regulatory pathways from the resultant experimental shape phenotypes. For example, planarian regeneration has been studied for over a century, but despite increasing insight into the pathways that control its stem cells, no constructive, mechanistic model has yet been found by human scientists that explains more than one or two key features of its remarkable ability to regenerate its correct anatomical pattern after drastic perturbations. We present a method to infer the molecular products, topology, and spatial and temporal non-linear dynamics of regulatory networks recapitulating in silico the rich dataset of morphological phenotypes resulting from genetic, surgical, and pharmacological experiments. We demonstrated our approach by inferring complete regulatory networks explaining the outcomes of the main functional regeneration experiments in the planarian literature; By analyzing all the datasets together, our system inferred the first systems-biology comprehensive dynamical model explaining patterning in planarian regeneration. This method provides an automated

  13. Experimental study and finite element analysis based on equivalent load method for laser ultrasonic measurement of elastic constants.

    PubMed

    Zhan, Yu; Liu, Changsheng; Zhang, Fengpeng; Qiu, Zhaoguo

    2016-07-01

    The laser ultrasonic generation of Rayleigh surface wave and longitudinal wave in an elastic plate is studied by experiment and finite element method. In order to eliminate the measurement error and the time delay of the experimental system, the linear fitting method of experimental data is applied. The finite element analysis software ABAQUS is used to simulate the propagation of Rayleigh surface wave and longitudinal wave caused by laser excitation on a sheet metal sample surface. The equivalent load method is proposed and applied. The pulsed laser is equivalent to the surface load in time and space domain to meet the Gaussian profile. The relationship between the physical parameters of the laser and the load is established by the correction factor. The numerical solution is in good agreement with the experimental result. The simple and effective numerical and experimental methods for laser ultrasonic measurement of the elastic constants are demonstrated. Copyright © 2016. Published by Elsevier B.V.

  14. Isoparametric fitting: A method for approximating full-field experimental data distributed on any shaped 3D domain

    NASA Astrophysics Data System (ADS)

    Bruno, Luigi

    2016-12-01

    With the present paper, the author proposes a fitting method for approximating experimental data retrieved from any full-field technique. Unlike most of the fitting procedures, the method works on data distributed on a surface of any shape, and the mathematical model is able to take into account of both the 3D shape of the surface and of the experimental quantity to be fitted. The paper reports all the mathematical steps necessary for applying the method, which was tested on two sets of experimental data obtained by an out-of-plane speckle interferometer working in two different conditions of noise. Experimental results showed the capability of the method to work in presence of high level of noise.

  15. "Tie over ring" sutureless compression based gastrointestinal anastomotic method: experimental rat model.

    PubMed

    Hiradfar, Mehran; Shojaeian, Reza; Zabolinejad, Nona; Gharavifard, Mohammad; Sabzevari, Alireza; Joodi, Marjan; Yal, Nazila; Saeedi Sharifabad, Parisa; Hajian, Sara; Nazarzadeh, Reza; Lotfinejad, Nasim

    2014-03-01

    Giving the ever-rising trend of pediatric minimally invasive surgery besides early neonatal surgical interventions, intestinal anastomosis turns out to be a time consuming stage due to several anatomical as well as technical difficulties. A perfect bowel anastomosis method should be easy, rapid, safe and reliable in creation of bowel continuity with minimal tissue damage. In this light, sutureless anastomotic methods have been introduced, using compression based anastomosis with biofragmentable rings or powerful magnets. Accordingly, this experimental animal model study has evaluated the result of an easy, rapid intestinal sutureless anastomotic technique via simple tying over an intraluminal ring, in comparison with conventional handsewn bowel anastomosis. Thirty Wistar-Albino male rats were enrolled and small bowel was transected via a midline laparotomy. A grooved plastic ring was inserted into the ileal lumen and both intestinal cutting ends were fixed over the ring with a simple tie in the first group. On the other hand, enteroenterostomy was performed by the conventional method of handsewn anastomosis in the second group. After 14 days, rats were sacrificed to evaluate for intraperitoneal adhesion and abscess formation in addition to other evidences of anastomotic leakage. Furthermore, the anastomotic site integrity, tensile strength and healing stage were assessed microscopically. The mean operative time and intraoperative bleeding in the tie over ring group were significantly less than those in the handsewn anastomosis group. Anastomotic stricture was more common in the conventional anastomosis group while the anastomotic tensile strength was significantly higher in the tie over ring group. Histopathological healing parameters and final healing score were almost similar in both groups but mean inflammatory cell infiltration in handsewn anastomosis was significantly higher. "Tie over ring" is a simple method of anastomosis that is feasible, fast, safe and

  16. TiO{sub 2} synthesized by microwave assisted solvothermal method: Experimental and theoretical evaluation

    SciTech Connect

    Moura, K.F.; Maul, J.; Albuquerque, A.R.; Casali, G.P.

    2014-02-15

    In this study, a microwave assisted solvothermal method was used to synthesize TiO{sub 2} with anatase structure. The synthesis was done using Ti (IV) isopropoxide and ethanol without templates or alkalinizing agents. Changes in structural features were observed with increasing time of synthesis and evaluated using periodic quantum chemical calculations. The anatase phase was obtained after only 1 min of reaction besides a small amount of brookite phase. Experimental Raman spectra are in accordance with the theoretical one. Micrometric spheres constituted by nanometric particles were obtained for synthesis from 1 to 30 min, while spheres and sticks were observed after 60 min. - Graphical abstract: FE-SEM images of anatase obtained with different periods of synthesis associated with the order–disorder degree. Display Omitted - Highlights: • Anatase microspheres were obtained by the microwave assisted hydrothermal method. • Only ethanol and titanium isopropoxide were used as precursors during the synthesis. • Raman spectra and XRD patterns were compared with quantum chemical calculations. • Time of synthesis increased the short-range disorder in one direction and decreased in another.

  17. Advanced Experimental Methods for Low-temperature Magnetotransport Measurement of Novel Materials.

    PubMed

    Hagmann, Joseph A; Le, Son T; Richter, Curt A; Seiler, David G

    2016-01-21

    Novel electronic materials are often produced for the first time by synthesis processes that yield bulk crystals (in contrast to single crystal thin film synthesis) for the purpose of exploratory materials research. Certain materials pose a challenge wherein the traditional bulk Hall bar device fabrication method is insufficient to produce a measureable device for sample transport measurement, principally because the single crystal size is too small to attach wire leads to the sample in a Hall bar configuration. This can be, for example, because the first batch of a new material synthesized yields very small single crystals or because flakes of samples of one to very few monolayers are desired. In order to enable rapid characterization of materials that may be carried out in parallel with improvements to their growth methodology, a method of device fabrication for very small samples has been devised to permit the characterization of novel materials as soon as a preliminary batch has been produced. A slight variation of this methodology is applicable to producing devices using exfoliated samples of two-dimensional materials such as graphene, hexagonal boron nitride (hBN), and transition metal dichalcogenides (TMDs), as well as multilayer heterostructures of such materials. Here we present detailed protocols for the experimental device fabrication of fragments and flakes of novel materials with micron-sized dimensions onto substrate and subsequent measurement in a commercial superconducting magnet, dry helium close-cycle cryostat magnetotransport system at temperatures down to 0.300 K and magnetic fields up to 12 T.

  18. Analysis of accommodation coefficients of noble gases on aluminum surface with an experimental/computational method

    NASA Astrophysics Data System (ADS)

    Selden, Nathaniel; Gimelshein, Natalia; Gimelshein, Sergey; Ketsdever, Andrew

    2009-07-01

    A method that connects measurements of radiometric forces on a heated vane in the transitional flow regime with the kinetic modeling of the flow, and derives the accommodation coefficients through the successive analysis of measured and computed results, is proposed. The method utilizes the fact that radiometric forces exerted on heated objects immersed in rarefied gases are governed by the interaction of gas molecules with the surface. Experimental results on radiometric forces on a 0.11 m diameter circular vane are obtained on a nano-Newton thrust stand in a 3 m long vacuum chamber for pressures ranging from approximately 0.01 to 1 Pa. The vane was heated to 419 K on the hot side and 396 K on the cold side. The numerical modeling is conducted using a combined ellipsoidal statistical Bhatnagar-Gross-Krook/direct simulation Monte Carlo approach that allows accurate and time efficient analysis of radiometric forces on a vane in large vacuum chambers filled with rarefied gas. Accommodation coefficients for the Maxwell model are estimated for argon, xenon, and helium on a machined aluminum surface, and found to be 0.81, 0.86, and 0.53, respectively.

  19. Vibrational studies on (E)-1-((pyridine-2-yl)methylene)semicarbazide using experimental and theoretical method

    NASA Astrophysics Data System (ADS)

    Subashchandrabose, S.; Ramesh Babu, N.; Saleem, H.; Syed Ali Padusha, M.

    2015-08-01

    The (E)-1-((pyridine-2-yl)methylene)semicarbazide (PMSC) was synthesized. The experimental and theoretical study on molecular structure and vibrational spectra were carried out. The FT-IR (400-4000 cm-1), FT-Raman (50-3500 cm-1) and UV-Vis (200-500 nm) spectra of PMSC were recorded. The geometric structure, conformational analysis, vibrational wavenumbers of PMSC in the ground state have been calculated using B3LYP method of 6-311++G(d,p) basis set. The complete vibrational assignments were made on the basis of TED, calculated by SQM method. The Non-linear optical activity was measured by means of first order hyperpolarizability calculation and π-electrons of conjugative bond in the molecule. The intra-molecular charge transfer, mode hyperconjugative interaction and molecular stabilization energies were calculated. The band gap energies between occupied and unoccupied molecular orbitals were analyzed; it proposes lesser band gap with more reactivity. To understand the electronic properties of this molecule the Mulliken charges were also calculated.

  20. A framework program for the teaching of alternative methods (replacement, reduction, refinement) to animal experimentation.

    PubMed

    Daneshian, Mardas; Akbarsha, Mohammad A; Blaauboer, Bas; Caloni, Francesca; Cosson, Pierre; Curren, Rodger; Goldberg, Alan; Gruber, Franz; Ohl, Frauke; Pfaller, Walter; van der Valk, Jan; Vinardell, Pilar; Zurlo, Joanne; Hartung, Thomas; Leist, Marcel

    2011-01-01

    Development of improved communication and education strategies is important to make alternatives to the use of animals, and the broad range of applications of the 3Rs concept better known and understood by different audiences. For this purpose, the Center for Alternatives to Animal Testing in Europe (CAAT-Europe) together with the Transatlantic Think Tank for Toxicology (t(4)) hosted a three-day workshop on "Teaching Alternative Methods to Animal Experimentation". A compilation of the recommendations by a group of international specialists in the field is summarized in this report. Initially, the workshop participants identified the different audience groups to be addressed and also the communication media that may be used. The main outcome of the workshop was a framework for a comprehensive educational program. The modular structure of the teaching program presented here allows adaptation to different audiences with their specific needs; different time schedules can be easily accommodated on this basis. The topics cover the 3Rs principle, basic research, toxicological applications, method development and validation, regulatory aspects, case studies and ethical aspects of 3Rs approaches. This expert consortium agreed to generating teaching materials covering all modules and providing them in an open access online repository.

  1. Experimental verification of the Interpolation Method on a real damaged bridge

    NASA Astrophysics Data System (ADS)

    Limongelli, M. P.; Morassi, A.

    2015-07-01

    The identification of damage in a bridge from changes in its vibrational behavior is an inverse problem of important practical value. Significant advances have been obtained on this topic in the last two-three decades, both from the theoretical and applied point of view. One of the main problems when dealing with the assessment of vibration based damage identification methods is the lack of experimental data recorded on real damaged structures. Due to this, a large number of damage identification algorithms are tested using data simulated by numerical models. The availability of data recorded on a damaged bridge before its demolition gave the authors the uncommon chance to verify the sensitivity and reliability of the IDDM basing on data recorded on a real structure. Specifically data recorded on a reinforced concrete single-span supported bridge in the Municipality of Dogna (Friuli, Italy) were used to apply the damage localization algorithm. Harmonically forced tests were conducted after imposing artificial, increasing levels of localized damage. In this paper the sensitivity of the method is discussed with respect to the number of instrumented locations and to the severity of the damage scenarios considered

  2. Experimental Sentinel-2 LAI estimation using parametric, non-parametric and physical retrieval methods - A comparison

    NASA Astrophysics Data System (ADS)

    Verrelst, Jochem; Rivera, Juan Pablo; Veroustraete, Frank; Muñoz-Marí, Jordi; Clevers, Jan G. P. W.; Camps-Valls, Gustau; Moreno, José

    2015-10-01

    Given the forthcoming availability of Sentinel-2 (S2) images, this paper provides a systematic comparison of retrieval accuracy and processing speed of a multitude of parametric, non-parametric and physically-based retrieval methods using simulated S2 data. An experimental field dataset (SPARC), collected at the agricultural site of Barrax (Spain), was used to evaluate different retrieval methods on their ability to estimate leaf area index (LAI). With regard to parametric methods, all possible band combinations for several two-band and three-band index formulations and a linear regression fitting function have been evaluated. From a set of over ten thousand indices evaluated, the best performing one was an optimized three-band combination according to (ρ560 -ρ1610 -ρ2190) / (ρ560 +ρ1610 +ρ2190) with a 10-fold cross-validation RCV2 of 0.82 (RMSECV : 0.62). This family of methods excel for their fast processing speed, e.g., 0.05 s to calibrate and validate the regression function, and 3.8 s to map a simulated S2 image. With regard to non-parametric methods, 11 machine learning regression algorithms (MLRAs) have been evaluated. This methodological family has the advantage of making use of the full optical spectrum as well as flexible, nonlinear fitting. Particularly kernel-based MLRAs lead to excellent results, with variational heteroscedastic (VH) Gaussian Processes regression (GPR) as the best performing method, with a RCV2 of 0.90 (RMSECV : 0.44). Additionally, the model is trained and validated relatively fast (1.70 s) and the processed image (taking 73.88 s) includes associated uncertainty estimates. More challenging is the inversion of a PROSAIL based radiative transfer model (RTM). After the generation of a look-up table (LUT), a multitude of cost functions and regularization options were evaluated. The best performing cost function is Pearson's χ -square. It led to a R2 of 0.74 (RMSE: 0.80) against the validation dataset. While its validation went fast

  3. Methods for exploring the morpho-functional relations of the aortic depressor nerve in experimental diabetes.

    PubMed

    do Carmo, Jussara Márcia; Júnior, Rubens Fazan; Salgado, Helio Cesar; Fazan, Valéria Paula Sassoli

    2011-01-30

    The present study investigated morpho-functional relations of the aortic depressor nerve (ADN) 5, 15 and 120 days after the onset of streptozotocin-induced diabetes in rats. Time control animals received vehicle. Under pentobarbital anesthesia, ADN activity was recorded simultaneously with arterial pressure. After the recordings, nerves were prepared for light microscopy study and morphometry. ADN function was accessed by means of pressure-nerve activity curve (fitted by sigmoidal regression) and cross-spectral analysis between mean arterial pressure (MAP) and ADN activity. The relation between morphological (myelinated fibers number and density, total myelin area, total fiber area and percentage of occupancy) and functional (gain, signal/noise relation, frequency) parameters were accessed by linear regression analysis and correlation coefficient calculations. Functional parameters obtained by means of the sigmoidal regression curve as well as by cross-spectral analysis were similar in diabetic and control rats. Morphometric parameters of the ADN were similar between groups 5 days after the onset of diabetes. Average myelin area and myelinated fiber area were significantly smaller on diabetic rats 15 and 120 days after the onset of diabetes, being the myelinated fiber and respective axons area and diameter also smaller on 120 days group. Nevertheless, G ratio (ratio between axon and fiber diameter) was nearly 0.6 and not different between groups or experimental times. No significant relationship between morphological and functional parameters was detected in all experimental groups. The present study suggests that ADN diabetic neuropathy was time-dependent, with damage to myelinated fibers to be the primary event, not evidenced by physiological methods.

  4. Experimental evaluation of rodent exclusion methods to reduce hantavirus transmission to humans in rural housing.

    PubMed

    Glass, G E; Johnson, J S; Hodenbach, G A; Disalvo, C L; Peters, C J; Childs, J E; Mills, J N

    1997-04-01

    An experimental assessment of methods to reduce rodent infestations in rural housing was conducted in Yosemite National Park, California, Sequoia/Kings Canyon National Parks, California, and Shenandoah National Park, Virginia. During pretreatment surveys, nearly all (63 of 68) selected units had past or ongoing rodent activity inside. Active infestations were found in 58.8% of the units. Peromyscus spp. represented 91.2% of all animals caught inside housing units. Despite little harborage, rodent activity was common near housing (290 animals/2,254 trap nights). The most common species present was Peromyscus maniculatus (43-50% of all captures). This species was especially frequent (49-87% of Peromyscus captures) around the foundations of housing units. Habitat had little effect on captures. There were 1.8 Peromyscus caught per unit along the foundations of housing in modified rural settings with grass lawns compared with 1.2 Peromyscus caught per unit in sites located in mature woodlands. During autumn of 1994, randomly selected housing units were rodent proofed by sealing openings associated with chases, roof eaves, and attics with insulation and wire mesh. Housing was examined and the fauna was resampled in the spring-summer of 1995. Rodent-proofed houses were infested significantly less often (3 of 28) than control houses (13 of 36) (P = 0.02) and the intensity of infestation was lower in experimental houses (6 versus 23 mice/treatment). More than 25% of the mice trapped inside the houses had been marked outside the houses during the three-day surveys, demonstrating movement of mice adjacent to the buildings into not rodent-proofed housing. As in the previous autumn, most of the animals captured in (98.9%) and along the foundations of the houses (77.5%) were Peromyscus spp. These results demonstrate that Peromyscus frequently invade rural housing but rodent-proofing effectively eliminates or substantially reduces rodent activity.

  5. The dynamics of a cantilevered pipe aspirating fluid studied by experimental, numerical and analytical methods

    NASA Astrophysics Data System (ADS)

    Giacobbi, Dana B.; Rinaldi, Stephanie; Semler, Christian; Païdoussis, Michael P.

    2012-04-01

    This paper investigates the dynamics of a slender, flexible, aspirating cantilevered pipe, ingesting fluid at its free end and conveying it towards its clamped end. The problem is interesting not only from a fundamental perspective, but also because applications exist, notably in ocean mining. First, the need for the present work is demonstrated through a review of previous research into the topic - spanning many years and yielding often contradictory results - most recently suggesting that the system loses stability by flutter at relatively low flow velocities. In the present paper, that conclusion is refined and expanded upon by exploring the problem in three ways: experimentally, numerically and analytically. First, air-flow experiments were conducted using different elastomer pipes and intake shapes, in which the flow velocity of the fluid was varied and the frequency and amplitude of oscillation of the pipe were measured. Second, a fully coupled Computational Fluid Dynamics (CFD) and Computational Structural Mechanics (CSM) model was developed in ANSYS™ in order to simulate experiments and corroborate experimental results. Finally, using a Newtonian analytical approach, a new linear equation of motion describing the system was derived, and then solved via the Galerkin method in order to determine its stability characteristics. Heavily influenced by the CFD analysis, the proposed analytical model is different from previous ones, most notably because of the inclusion of a two-part fluid depressurisation at the intake. In general, both the actual and numerical experiments suggest a first-mode loss of stability by flutter at flow velocities comparable to those for the discharging case, which agrees with the results from the new analytical model.

  6. On the Use of Experimental Methods to Improve Confidence in Educed Impedance

    NASA Technical Reports Server (NTRS)

    Jones, Michael G.; Watson, Willie R.

    2011-01-01

    Results from impedance eduction methods developed by NASA Langley Research Center are used throughout the acoustic liner community. In spite of recent enhancements, occasional anomalies persist with these methods, generally at frequencies where the liner produces minimal attenuation. This investigation demonstrates an experimental approach to educe impedance with increased confidence over a desired frequency range, by combining results from successive tests with different cavity depths. A series of tests is conducted with three wire-mesh facesheets, for which the results should be weakly dependent on source sound pressure level and mean grazing flow speed. First, a raylometer is used to measure the DC flow resistance of each facesheet. These facesheets are then mounted onto a frame and a normal incidence tube is used to determine their respective acoustic impedance spectra. A comparison of the acoustic resistance component with the DC flow resistance for each facesheet is used to validate the measurement process. Next, each facesheet is successively mounted onto three frames with different cavity depths, and a grazing flow impedance tube is used to educe their respective acoustic impedance spectra with and without mean flow. The no-flow results are compared with those measured in the normal incidence tube to validate the impedance eduction method. Since the anti-resonance frequency varies with cavity depth, each sample provides robust results over a different frequency range. Hence, a combination of results can be used to determine the facesheet acoustic resistance. When combined with the acoustic reactance, observed to be weakly dependent on the source sound pressure level and grazing flow Mach number, the acoustic impedance can be educed with increased confidence. Representative results of these tests are discussed, and the complete database is available in electronic format upon request.

  7. Linking experimental results, biological networks and sequence analysis methods using Ontologies and Generalised Data Structures.

    PubMed

    Koehler, Jacob; Rawlings, Chris; Verrier, Paul; Mitchell, Rowan; Skusa, Andre; Ruegg, Alexander; Philippi, Stephan

    2005-01-01

    The structure of a closely integrated data warehouse is described that is designed to link different types and varying numbers of biological networks, sequence analysis methods and experimental results such as those coming from microarrays. The data schema is inspired by a combination of graph based methods and generalised data structures and makes use of ontologies and meta-data. The core idea is to consider and store biological networks as graphs, and to use generalised data structures (GDS) for the storage of further relevant information. This is possible because many biological networks can be stored as graphs: protein interactions, signal transduction networks, metabolic pathways, gene regulatory networks etc. Nodes in biological graphs represent entities such as promoters, proteins, genes and transcripts whereas the edges of such graphs specify how the nodes are related. The semantics of the nodes and edges are defined using ontologies of node and relation types. Besides generic attributes that most biological entities possess (name, attribute description), further information is stored using generalised data structures. By directly linking to underlying sequences (exons, introns, promoters, amino acid sequences) in a systematic way, close interoperability to sequence analysis methods can be achieved. This approach allows us to store, query and update a wide variety of biological information in a way that is semantically compact without requiring changes at the database schema level when new kinds of biological information is added. We describe how this datawarehouse is being implemented by extending the text-mining framework ONDEX to link, support and complement different bioinformatics applications and research activities such as microarray analysis, sequence analysis and modelling/simulation of biological systems. The system is developed under the GPL license and can be downloaded from http://sourceforge.net/projects/ondex/

  8. Experimental investigation of a new method for advanced fast reactor shutdown cooling

    NASA Astrophysics Data System (ADS)

    Pakholkov, V. V.; Kandaurov, A. A.; Potseluev, A. I.; Rogozhkin, S. A.; Sergeev, D. A.; Troitskaya, Yu. I.; Shepelev, S. F.

    2017-07-01

    We consider a new method for fast reactor shutdown cooling using a decay heat removal system (DHRS) with a check valve. In this method, a coolant from the decay heat exchanger (DHX) immersed into the reactor upper plenum is supplied to the high-pressure plenum and, then, inside the fuel subassemblies (SAs). A check valve installed at the DHX outlet opens by the force of gravity after primary pumps (PP-1) are shut down. Experimental studies of the new and alternative methods of shutdown cooling were performed at the TISEY test facility at OKBM. The velocity fields in the upper plenum of the reactor model were obtained using the optical particle image velocimetry developed at the Institute of Applied Physics (Russian Academy of Sciences). The study considers the process of development of natural circulation in the reactor and the DHRS models and the corresponding evolution of the temperature and velocity fields. A considerable influence of the valve position in the displacer of the primary pump on the natural circulation of water in the reactor through the DHX was discovered (in some modes, circulation reversal through the DHX was obtained). Alternative DHRS designs without a shell at the DHX outlet with open and closed check valve are also studied. For an open check valve, in spite of the absence of a shell, part of the flow is supplied through the DHX pipeline and then inside the SA simulators. When simulating power modes of the reactor operation, temperature stratification of the liquid was observed, which increased in the cooling mode via the DHRS. These data qualitatively agree with the results of tests at BN-600 and BN-800 reactors.

  9. Experimental validation of a multi-energy x-ray adapted scatter separation method

    NASA Astrophysics Data System (ADS)

    Sossin, A.; Rebuffel, V.; Tabary, J.; Létang, J. M.; Freud, N.; Verger, L.

    2016-12-01

    Both in radiography and computed tomography (CT), recently emerged energy-resolved x-ray photon counting detectors enable the identification and quantification of individual materials comprising the inspected object. However, the approaches used for these operations require highly accurate x-ray images. The accuracy of the images is severely compromised by the presence of scattered radiation, which leads to a loss of spatial contrast and, more importantly, a bias in radiographic material imaging and artefacts in CT. The aim of the present study was to experimentally evaluate a recently introduced partial attenuation spectral scatter separation approach (PASSSA) adapted for multi-energy imaging. For this purpose, a prototype x-ray system was used. Several radiographic acquisitions of an anthropomorphic thorax phantom were performed. Reference primary images were obtained via the beam-stop (BS) approach. The attenuation images acquired from PASSSA-corrected data showed a substantial increase in local contrast and internal structure contour visibility when compared to uncorrected images. A substantial reduction of scatter induced bias was also achieved. Quantitatively, the developed method proved to be in relatively good agreement with the BS data. The application of the proposed scatter correction technique lowered the initial normalized root-mean-square error (NRMSE) of 45% between the uncorrected total and the reference primary spectral images by a factor of 9, thus reducing it to around 5%.

  10. An electrophysiological method for monitoring blood flow in skeletal muscle. An experimental study in the rat.

    PubMed

    Larsson, L

    1989-01-01

    An experimental animal model was used to study the effects of occlusion of skeletal muscle blood flow on spontaneous denervation activity (fibrillation potentials). The aim was to investigate whether recording of fibrillation potentials could provide a valuable electrophysiological technique for monitoring muscle tissue circulation during free flap surgery. In both the fast-twitch anterior tibial muscle and the slow-twitch soleus, the number of fibrillation potentials decreased rapidly (within 30 sec) after occlusion of the blood flow and after 5 min only few fibrillation potentials were present. In the fast-twitch muscle, the fibrillation potentials disappeared within 10 min in most animals, but sporadic potentials were seen for up to 18 min in one animal after the blood vessels were clamped. In the slow-twitch muscle, sporadic single fibrillation potentials were seen for a longer time than in the anterior tibial muscle and fibrillation potentials were often observed for more than 20 min after clamping of the blood vessels. However, the initial decrease in the number of fibrillation potentials was rapid in both muscles. This means, if the same is true in human muscle, that the method is sufficiently rapid to permit restoration of the circulation so that the muscle flap can be saved if the blood flow is occluded after a muscle transfer operation. Thus, recording of fibrillation potentials may provide a powerful and simple technique for monitoring free flap circulation.

  11. Nanostructure Characterization of Bismuth Telluride-Based Powders and Extruded Alloys by Various Experimental Methods

    NASA Astrophysics Data System (ADS)

    Vasilevskiy, D.; Bourbia, O.; Gosselin, S.; Turenne, S.; Masut, R. A.

    2011-05-01

    High-resolution transmission electron microscopy (HRTEM) observations of mechanically alloyed powders and bulk extruded alloys give experimental evidence of nanosized grains in bismuth telluride-based materials. In this study we combine HRTEM observations and x-ray diffraction (XRD) measurements, of both mechanically alloyed powders and extruded samples, with mechanical spectroscopy (MS) of extruded rods. Both HRTEM and XRD show that nanostructures with an average grain size near 25 nm can be achieved within 2 h of mechanical alloying from pure elements in an attritor-type milling machine. Residual strain orthogonal to the c-axis of powder nanoparticles has been evaluated at about 1.2% by XRD peak broadening. In contrast, XRD has been found unreliable for evaluation of grain size in highly textured extruded materials for which diffraction conditions are similar to those of single crystals, while MS appears promising for study of bulk extruded samples. Nanostructured extruded alloys at room temperature exhibit an internal friction (IF) background that is one order of magnitude higher than that of conventional zone-melted material with a grain size of several millimeters. IF as a function of sample temperature gives activation energies that are also different between bulk materials having nano- and millimeter-size grains, a result that is attributed to different creep mechanisms. Nanograin size, as well as orientation and volumetric proportion, provide valuable information for optimization of technological parameters of thermoelectric alloys and should be carefully cross-examined by various independent methods.

  12. The 'triple contrast' method in experimental wound ballistics and backspatter analysis.

    PubMed

    Schyma, Christian; Lux, Constantin; Madea, Burkhard; Courts, Cornelius

    2015-09-01

    In practical forensic casework, backspatter recovered from shooters' hands can be an indicator of self-inflicted gunshot wounds to the head. In such cases, backspatter retrieved from inside the barrel indicates that the weapon found at the death scene was involved in causing the injury to the head. However, systematic research on the aspects conditioning presence, amount and specific patterns of backspatter is lacking so far. Herein, a new concept of backspatter investigation is presented, comprising staining technique, weapon and target medium: the 'triple contrast method' was developed, tested and is introduced for experimental backspatter analysis. First, mixtures of various proportions of acrylic paint for optical detection, barium sulphate for radiocontrast imaging in computed tomography and fresh human blood for PCR-based DNA profiling were generated (triple mixture) and tested for DNA quantification and short tandem repeat (STR) typing success. All tested mixtures yielded sufficient DNA that produced full STR profiles suitable for forensic identification. Then, for backspatter analysis, sealed foil bags containing the triple mixture were attached to plastic bottles filled with 10% ballistic gelatine and covered by a 2-3-mm layer of silicone. To simulate backspatter, close contact shots were fired at these models. Endoscopy of the barrel inside revealed coloured backspatter containing typable DNA and radiographic imaging showed a contrasted bullet path in the gelatine. Cross sections of the gelatine core exhibited cracks and fissures stained by the acrylic paint facilitating wound ballistic analysis.

  13. Experimental Evaluation of a Method for Turbocharging Four-Stroke, Single Cylinder, Internal Combustion Engines

    NASA Astrophysics Data System (ADS)

    Buchman, Michael; Winter, Amos

    2015-11-01

    Turbocharging an engine increases specific power, improves fuel economy, reduces emissions, and lowers cost compared to a naturally aspirated engine of the same power output. These advantages make turbocharging commonplace for multi-cylinder engines. Single cylinder engineers are not commonly turbocharged due to the phase lag between the exhaust stroke, which powers the turbocharger, and the intake stroke, when air is pumped into the engine. Our proposed method of turbocharging single cylinder engines is to add an ``air capacitor'' to the intake manifold, an additional volume that acts as a buffer to store compressed air between the exhaust and intake strokes, and smooth out the pressure pulses from the turbocharger. This talk presents experimental results from a single cylinder, turbocharged diesel engine fit with various sized air capacitors. Power output from the engine was measured using a dynamometer made from a generator, with the electrical power dissipated with resistive heating elements. We found that intake air density increases with capacitor size as theoretically predicted, ranging from 40 to 60 percent depending on heat transfer. Our experiment was able to produce 29 percent more power compared to using natural aspiration. These results validated that an air capacitor and turbocharger may be a simple, cost effective means of increasing the power density of single cylinder engines.

  14. Theoretical and experimental investigations on measuring underwater temperature by the coherent Brillouin scattering method.

    PubMed

    Ren, Xiuyun; Tian, Zhaoshuo; Zhang, Yanchao; Wang, Ling; Fu, Shiyou

    2015-10-20

    In this paper, a new method of measuring a water-stimulated Brillouin scattering (SBS) frequency shift by optical coherent detection is presented, in order to remote-sense the underwater temperature of the ocean. A single longitudinal mode, passively Q-switched pulsed Nd:YAG laser is used as the light source, the water SBS beam is used as the signal beam, and a portion of the incident laser beam is used as the local oscillator. The heterodyne is detected by a high-speed photodetector, and the heterodyne frequency is the Brillouin frequency shift. Therefore, the underwater temperature can be determined according to the relationship between the Brillouin frequency shift and the water temperature. To test and verify its practicability, the heterodyne waveforms at different water temperatures are recorded in the laboratory with a wide-band oscilloscope, and the Brillouin frequency shifts are deduced by a Fourier transform. The experimental results are consistent with the theoretical analysis. This work provides the foundation for the development of a water temperature measurement system based on coherent Brillouin scattering.

  15. Numerical and Experimental Methods for Wake Flow Analysis in Complex Terrain

    NASA Astrophysics Data System (ADS)

    Castellani, Francesco; Astolfi, Davide; Piccioni, Emanuele; Terzi, Ludovico

    2015-06-01

    Assessment and interpretation of the quality of wind farms power output is a non-trivial task, which poses at least three main challenges: reliable comprehension of free wind flow, which is stretched to the limit on very complex terrains, realistic model of how wake interactions resemble on the wind flow, awareness of the consequences on turbine control systems, including alignment patterns to the wind and, consequently, power output. The present work deals with an onshore wind farm in southern Italy, which has been a test case of IEA- Task 31 Wakebench project: 17 turbines, with 2.3 MW of rated power each, are sited on a very complex terrain. A cluster of machines is investigated through numerical and experimental methods: CFD is employed for simulating wind fields and power extraction, as well as wakes, are estimated through the Actuator Disc model. SCADA data mining techniques are employed for comparison between models and actual performances. The simulations are performed both on the real terrain and on flat terrain, in order to disentangle the effects of complex flow and wake effects. Attention is devoted to comparison between actual alignment patterns of the cluster of turbines and predicted flow deviation.

  16. Virtual reality immersion method of distraction to control experimental ischemic pain.

    PubMed

    Magora, Florella; Cohen, Sarale; Shochina, Mara; Dayan, Ehud

    2006-04-01

    Virtual reality immersion has been advocated as a new effective adjunct to drugs for pain control. The attenuation of pain perception and unpleasantness has been attributed to the patient's attention being diverted from the real, external environment through immersion in a virtual environment transmitted by an interactive 3-D software computer program via a VR helmet. To investigate whether VR immersion can extend the amount of time subjects can tolerate ischemic tourniquet pain. The study group comprised 20 healthy adult volunteers. The pain was induced by an inflated blood pressure cuff during two separate, counterbalanced, randomized experimental conditions for each subject: one with VR and the control without VR exposure. The VR equipment consisted of a standard computer, a lightweight helmet and an interactive software game. Tolerance time to ischemia was significantly longer for VR conditions than for those without (P < 0.001). Visual Analogue Scale (0-10) ratings were recorded for pain intensity, pain unpleasantness, and the time spent thinking about pain. Affective distress ratings of unpleasantness and of time spent thinking about pain were significantly lower during VR as compared with the control condition (P< 0.003 and 0.001 respectively). The VR method in pain control was shown to be beneficial. The relatively inexpensive equipment will facilitate the use of VR immersion in clinical situations. Future research is necessary to establish the optimal selection of clinical patients appropriate for VR pain therapy and the type of software required according to age, gender, personality, and cultural factors.

  17. The birth of experimental psychology in Germany between psychophysical methods and physiological theories.

    PubMed

    Sinatra, Maria

    2006-01-01

    In 1879 Wundt's laboratory of psychology was opened in Leipzig, and it has been the landmark ever since for the beginning of modern experimental psychology. Its founder, Wilhelm Maximilian Wundt, was the first to successfully demarcate the areas of scientific psychology as being distinct from either physiology or philosophy, thus guaranteeing the survival of psychology, which was regarded as an autonomous discipline set upon a secure institutional framework. This paper attempts to clarify the basic facts and concepts related to the roots of scientific psychology in Germany, i.e., the context in which the "Founding Father" worked, as well as of those predecessors who proposed the topics and apparatus of his laboratory. Attention will be paid in particular to the psychophysical methods of Weber and Fechner, especially in regard to colour perception. In this context, an outline is presented of the history of reaction time experiments in astronomy, physiology, and psychology, and of the role played by the scientific instruments. It is shown how the methodology of physics and physiology contributed to the emancipation of scientific psychology and to the formation of its orientation.

  18. Vibration Prediction Method of Electric Machines by using Experimental Transfer Function and Magnetostatic Finite Element Analysis

    NASA Astrophysics Data System (ADS)

    Saito, A.; Kuroishi, M.; Nakai, H.

    2016-09-01

    This paper concerns the noise and structural vibration caused by rotating electric machines. Special attention is given to the magnetic-force induced vibration response of interior-permanent magnet machines. In general, to accurately predict and control the vibration response caused by the electric machines, it is inevitable to model not only the magnetic force induced by the fluctuation of magnetic fields, but also the structural dynamic characteristics of the electric machines and surrounding structural components. However, due to complicated boundary conditions and material properties of the components, such as laminated magnetic cores and varnished windings, it has been a challenge to compute accurate vibration response caused by the electric machines even after their physical models are available. In this paper, we propose a highly-accurate vibration prediction method that couples experimentally-obtained discrete structural transfer functions and numerically-obtained distributed magnetic-forces. The proposed vibration synthesis methodology has been applied to predict vibration responses of an interior permanent magnet machine. The results show that the predicted vibration response of the electric machine agrees very well with the measured vibration response for several load conditions, for wide frequency ranges.

  19. Monitoring an Experimental Reactor Using the Group Method of Data Handling Approach

    SciTech Connect

    Martinez Goncalves, Iraci Martinez; Ting, Daniel K.S.; Ferreira, Paulo Brasko; Upadhyaya, Belle R

    2005-01-15

    This paper presents a reactor-monitoring algorithm using the group method of data handling (GMDH) that creates nonlinear algebraic models for system characterization. The monitoring system was applied to the IEA-R1 experimental reactor at the Instituto de Pesquisas Energeticas e Nucleares (IPEN). The IEA-R1 is a 5-MW pool-type research reactor that uses light water as coolant and moderator and graphite as reflector. The GMDH provides a general framework for characterizing the relationships among a set of state variables of a process system and is used for generating estimates of critical variables in an optimal data-driven model form. The monitoring system developed in this work was used to predict the IEA-R1 reactor environment, using nuclear power, rod position, and coolant temperatures, by combining two variables at a time. The results obtained using the GMDH models agreed very well with the dose rate measurements, with prediction errors of less than 5%. The error was minimal when the dose rate prediction was made using reactor power and coolant temperature.

  20. Detecting method of subjects' 3D positions and experimental advanced camera control system

    NASA Astrophysics Data System (ADS)

    Kato, Daiichiro; Abe, Kazuo; Ishikawa, Akio; Yamada, Mitsuho; Suzuki, Takahito; Kuwashima, Shigesumi

    1997-04-01

    Steady progress is being made in the development of an intelligent robot camera capable of automatically shooting pictures with a powerful sense of reality or tracking objects whose shooting requires advanced techniques. Currently, only experienced broadcasting cameramen can provide these pictures.TO develop an intelligent robot camera with these abilities, we need to clearly understand how a broadcasting cameraman assesses his shooting situation and how his camera is moved during shooting. We use a real- time analyzer to study a cameraman's work and his gaze movements at studios and during sports broadcasts. This time, we have developed a detecting method of subjects' 3D positions and an experimental camera control system to help us further understand the movements required for an intelligent robot camera. The features are as follows: (1) Two sensor cameras shoot a moving subject and detect colors, producing its 3D coordinates. (2) Capable of driving a camera based on camera movement data obtained by a real-time analyzer. 'Moving shoot' is the name we have given to the object position detection technology on which this system is based. We used it in a soccer game, producing computer graphics showing how players moved. These results will also be reported.

  1. [Claude Bernard, the experimental method, and the Société de Biologie].

    PubMed

    Bange, Christian

    2009-01-01

    Claude Bernard was one of the founder of the Société de Biologie created in 1849. He actively took part to it from its very beginning by presenting various communications and several important memoirs. Epistemological thoughts found in these memoirs lead to the methodological chapters introducing the volumes of his edited lessons given at the Collège de France. In 1865, these texts formed the basis to his Introduction à l'étude de la Médecine expérimentale, in which Bernard claims the experimental method should rely on the principle of determinism of the phenomena of Life. He was a dutiful President of the Société from 1867 until his death. He nevertheless was not often involved in debates, but agreed on the defense of the scientific principles he had claimed. He remained influential until his death, as noted in 1899 by the report Engène Gley wrote on the Société de Biologie during its fifty first years. Gley points regularly to Bernard's axioms which remained the true scientific credo of French biologists.

  2. Theoretical and experimental methods for in situ infrared spectroelectrochemistry of organic monomolecular films

    SciTech Connect

    Popenoe, D.D.

    1992-09-09

    This work describes the theoretical analysis, experimental development, and application of an in situ spectroelectrochemical cell for measuring infrared reflection-absorption spectra (IRRAS) of monolayer-coated Au surfaces beneath a thin aqueous overlayer. The cell allows the interchange of sample and reference substrates, thereby facilitating IRRAS of long-chain alkanethiolates in the C-H stretching region without electrochemical or polarization-modulation methods. The same in situ cell is combined with electrochemical modulation to study monolayers self-assembled from 11-mercaptoundecyl ferrocenecarboxylate (FcCOOC{sub 11}SH) at gold and to correlate the monolayer structure and composition with the ferrocenyl redox chemistry. An electrochemically active monolayer of an alkanethiolate derivatized with a flavin, formed by self-assembly from ethanolic solutions of 11,11'-dithiobisundecanoic acid, bis(2-(7,8-dimethyl-10-isoalloxazino)ethyl) ester, is described. IRRAS of the film, which is a candidate for future in situ spectroscopic studies, are presented and compared with transmission spectra of bulk analogs.

  3. Theoretical and experimental methods for in situ infrared spectroelectrochemistry of organic monomolecular films

    SciTech Connect

    Popenoe, D.D.

    1992-09-09

    This work describes the theoretical analysis, experimental development, and application of an in situ spectroelectrochemical cell for measuring infrared reflection-absorption spectra (IRRAS) of monolayer-coated Au surfaces beneath a thin aqueous overlayer. The cell allows the interchange of sample and reference substrates, thereby facilitating IRRAS of long-chain alkanethiolates in the C-H stretching region without electrochemical or polarization-modulation methods. The same in situ cell is combined with electrochemical modulation to study monolayers self-assembled from 11-mercaptoundecyl ferrocenecarboxylate (FcCOOC{sub 11}SH) at gold and to correlate the monolayer structure and composition with the ferrocenyl redox chemistry. An electrochemically active monolayer of an alkanethiolate derivatized with a flavin, formed by self-assembly from ethanolic solutions of 11,11`-dithiobisundecanoic acid, bis[2-(7,8-dimethyl-10-isoalloxazino)ethyl] ester, is described. IRRAS of the film, which is a candidate for future in situ spectroscopic studies, are presented and compared with transmission spectra of bulk analogs.

  4. Supermicrosurgery and hyaluronic acid: experimental feasability study of a new method.

    PubMed

    Qassemyar, Q; Gianfermi, M

    2015-02-01

    As a technique of anastomosis for vessels of less than 0.8mm in diameter, supermicrosurgery has aroused renewed interest on account of its potential clinical applications. The technical difficulty of surgery at such a small scale necessitates exploration of new methods likely to render the anastomoses accessible and reliable. The aim of this article is to present the results of an experimental study on the feasibility of anastomoses (arterial diameter ≤0.5mm), assisted by the injection of hyaluronic acid (HA). Ten end-to-end arterial anastomoses of the inferior epigastric artery (diameter ≤0.5mm) were performed in 5 rats. An injection of HA had previously been carried out in the vessel lumen and the sutures were made with 12-0 nylon. Immediate and 3-day permeability were controlled and anastomosis times were measured. Average diameter of the arteries was 0.42 mm (range 0.29-0.48 mm). Mean anastomosis duration was 19.5 min (range 15-23 min). The average number of stitches was 6. Immediate patency was 100% with a success rate of 80% at 3 days. The properties of HA seem to effectively facilitate anastomoses of arteries with a diameter ≤0.5mm. HA provides comfort and promotes safety in performance of exceedingly small-scale surgery. While the results appear promising, but further studies are needed in order to determine the potential toxicity of this method on tissues. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  5. Experimental Investigation of Pressure-volume-Temperature Mass Gauging Method Under Microgravity Condition by Parabolic Flight

    NASA Astrophysics Data System (ADS)

    Seo, Mansu; Park, Hana; Yoo, DonGyu; Jung, Youngsuk; Jeong, Sangkwon

    Gauging the volume or mass of liquid propellant of a rocket vehicle in space is an important issue for its economic feasibility and optimized design of loading mass. Pressure-volume-temperature (PVT) gauging method is one of the most suitable measuring techniques in space due to its simplicity and reliability. This paper presents unique experimental results and analyses of PVT gauging method using liquid nitrogen under microgravity condition by parabolic flight. A vacuum-insulated and cylindrical-shaped liquid nitrogen storage tank with 9.2 L volume is manufactured by observing regulation of parabolic flight. PVT gauging experiments are conducted under low liquid fraction condition from 26% to 32%. Pressure, temperature, and the injected helium mass into the storage tank are measured to obtain the ullage volume by gas state equation. Liquid volume is finally derived by the measured ullage volume and the known total tank volume. Two sets of parabolic flights are conducted and each set is composed of approximately 10 parabolic flights. In the first set of flights, the short initial waiting time (3 ∼ 5 seconds) cannot achieve sufficient thermal equilibrium condition at the beginning. It causes inaccurate gauging results due to insufficient information of the initial helium partial pressure in the tank. The helium injection after 12 second waiting time at microgravity condition with high mass flow rate in the second set of flights achieves successful initial thermal equilibrium states and accurate measurement results of initial helium partial pressure. Liquid volume measurement errors in the second set are within 11%.

  6. Technology Acceptance and Course Completion Rates in Online Education: A Non-experimental, Mixed Method Study

    NASA Astrophysics Data System (ADS)

    Allison, Colelia

    As the need for quality online courses increase in demand, the acceptance of technology and completion rates become the focus of higher education. The purpose of this non-experimental, mixed method study was to examine the relationship between the university students' perceptions and acceptance of technology and learner completion rates with respect to the development of online courses. This study involved 61 participants from two universities regarding their perceived usefulness (PU) of technology, intent to use technology, and intent to complete a course. Two research questions were examined regarding student perceptions regarding technology employed in an online course and the relationship, if any, between technology acceptance and completion of an online university course. The technology acceptance model (TAM) was used to collect data on the usefulness of course activities and student intent to complete the course. An open-ended questionnaire was administered to collect information concerning student perceptions of course activities. Quantitative data was analyzed using SPSS and Qualtrics, which indicated there was not a significant relationship between technology acceptance and course completion (p = .154). Qualitative data were examined by pattern matching to create a concept map of the theoretical patterns between constructs. Pattern matching revealed many students favored the use of the Internet over Canvas. Furthermore, data showed students enrolled in online courses because of the flexibility and found the multimedia used in the courses as helpful in course completion. Insight was investigated to offer reasons and decisions concerning choice that were made by the students. Future recommendations are to expand mixed methods studies of technology acceptance in various disciplines to gain a better understanding of student perceptions of technology uses, intent to use, and course completion.

  7. [Evaluation methods of nightguard teeth bleaching with opalescence (ultradent) based on clinical and experimental tests].

    PubMed

    Petrasz, Małgorzata

    2003-01-01

    In March 1989 Haywood and Heymann presented a new method for bleaching teeth called by them "nightguard vital bleaching". This procedure requires that the patient wears for 6 to 8 hours an individually designed guard filled with a viscous solution of carbamide peroxide. The aim of the present study was to determine the efficiency of the guard bleaching method and to address frequently asked questions concerning local complications and the influence of the preparation on the enamel surface. The scanning electron microscope was used in the experimental part to reveal changes in microhardness and on the surface of the bleached human enamel. The purpose of the clinical part was to determine the efficiency of bleaching, to estimate the frequency of pain and other symptoms and to check the influence of bleaching guard on accumulation of dental plaque and gingival status as reflected by the Plaque Index (Pl.I.) and the Gingival Index (G.I.). It was found that bleaching with 10, 20 or 35% carbamide peroxide reduced the microhardness and modified the morphology of enamel surface proportionally to the concentration of the bleaching agent. It was ascertained that 10% carbamide peroxide effectively bleached teeth and considerably improved the hygiene of the oral cavity and gingival status (Pl.I, G.I.). During bleaching, over half of the patients suffered from local complications--thermal hypersensitivity of teeth and irritation of gums. Some deterioration of the bleaching effect was observed after 12 months in females only. Almost 100% of the patients were satisfied with the results of bleaching and would recommend this procedure to family members.

  8. Convergent methods assessing bone growth in an experimental model at dental implants in the minipig.

    PubMed

    Friedmann, Anton; Friedmann, Asisa; Grize, Leticia; Obrecht, Marcel; Dard, Michel

    2014-05-01

    Implant dentistry demonstrated its reliability in treating successfully an increased amount of patients with dental implants exhibiting hydrophilic (modSLA) or non-hydrophilic (SLA) surfaces. Objectives of this minipig study consisted in assessing bone regeneration at both types of dental implants in a new experimental model (lateral bone defects) by implementing a convergent analysis approach combining histology and contact radiography. In six adult female minipigs standardized acute alveolar defects were created, then receiving two implants in the mandibles bilaterally (modSLA and SLA, one of each combined with Guided Bone Regeneration). Animals were sacrificed after 28 days of healing. Mid-crestal specimen were analyzed assessing missing BIC to implant shoulder (fBIC); vertical bone growth upon implant surface, bone:tissue ratio and grafting material area occupied by material remnants for GBR sites. Values obtained from both analyses were compared and statistical correlations scrutinized. Although dimensions of mean differences and adjusted means given by radiographic method were lower than histological ones, comparison of different implants yielded similar results. Statistical analyses of correlation and concordance coefficients used to evaluate radiological method of measurement showed high level of concordance (concordance coefficient=0.912 and correlation coefficient=0.939) for fBIC. Similar results were observed for vertical new bone and for remnants of graft. Discrepancies for new bone and for mineralized tissue resulted in concordance coefficient of 0.182 and 0.054. The results indicate that contact X-rays can be used for morphometric assessments regarding defect fill; however, histological staining remains beneficial if greater resolution for distinguishing qualitative differences in the tissues is required.

  9. Heat capacity of liquid organic compounds: Experimental determination and method of group approximation of its temperature dependence

    NASA Astrophysics Data System (ADS)

    Vasil'Ev, I. A.; Treibsho, E. I.; Korkhov, A. D.; Petrov, V. M.; Orlova, N. G.; Balakina, M. M.

    1981-06-01

    The article describes the experimental method and presents results of the investigation of the heat capacity of liquid n-alcohols and esters. It examines the method of group approximation of the temperature dependence on the example of n-alkanes and n-alkenes.

  10. Methodological Issues in Analog Acceptability Research: Are Teachers' Acceptability Ratings of Assessment Methods Influenced by Experimental Design?

    ERIC Educational Resources Information Center

    Eckert, Tanya L.; Shapiro, Edward S.

    1999-01-01

    Explores the relationship between experimental design method and teacher-rated acceptability of two analog approaches for assessing academic skills problems. Comparisons indicate that curriculum-based assessment was consistently rated as a more acceptable method of assessment than published, norm-referenced tests. Results are discussed in relation…

  11. Correction of steel casing effect for density log using numerical and experimental methods in the slim borehole

    SciTech Connect

    Hwang, Seho; Shin, Jehyun; Kim, Jongman; Won, Byeongho

    2015-03-10

    Density log is widely applied for a variety of fields such as the petroleum exploration, mineral exploration, and geotechnical survey. The logging condition of density log is normally open holes but there are frequently cased boreholes. The primary calibration curve by slim hole logging manufacturer is normally the calibration curves for the variation of borehole diameter. In this study, we have performed the correction of steel casing effects using numerical and experimental methods. We have performed numerical modeling using the Monte Carlo N-Particle (MCNP) code based on Monte Carlo method, and field experimental method from open and cased hole log. In this study, we used the FDGS (Formation Density Gamma Sonde) for slim borehole with a 100 mCi 137Cs source, three inch borehole and steel casing. The casing effect between numerical and experimental method is well matched.

  12. Improvement of mechanical properties of polymeric composites: Experimental methods and new systems

    NASA Astrophysics Data System (ADS)

    Nguyen, Felix Nhanchau

    Filler- (e.g., particulate or fiber) reinforced structural polymers or polymeric composites have changed the way things are made. Today, they are found, for example, in air/ground transportation vehicles, sporting goods, ballistic barrier applications and weapons, electronic packaging, musical instruments, fashion items, and more. As the demand increases, so does the desire to have not only well balanced mechanical properties, but also light weight and low cost. This leads to a constant search for novel constituents and additives, new fabrication methods and analytical techniques. To achieve new or improved composite materials requires more than the identification of the right reinforcements to be used with the right polymer matrix at the right loading. Also, an optimized adhesion between the two phases and a toughened matrix system are needed. This calls for new methods to predict, modify and assess the level of adhesion, and new developments in matrix tougheners to minimize compromises in other mechanical/thermal properties. Furthermore, structural optimization, associated with fabrication (e.g., avoidance of fiber-fiber touching or particle aggregation), and sometimes special properties, such as electrical conductivity or magnetic susceptibility are necessary. Finally, the composite system's durability, often under hostile conditions, is generally mandatory. The present study researches new predictive and experimental methods for optimizing and characterizing filler-matrix adhesion and develops a new type of epoxy tougheners. Specifically, (1) a simple thermodynamic parameter evaluated by UNIFAC is applied successfully to screen out candidate adhesion promoters, which is necessary for optimization of the physio-chemical interactions between the two phases; (2) an optical-acoustical mechanical test assisted with an acoustic emission technique is developed to de-convolute filler debonding/delamination among many other micro failure events, and (3) novel core

  13. New theoretical and experimental methods for pressure broadened linewidths and their interpretation

    NASA Technical Reports Server (NTRS)

    Gelfand, J. J.

    1982-01-01

    A review of recent progress in the theory of collisional line broadening, particularly the impact of recent advances in collision dynamics calculations is presented. Some new approaches to the interpretation of experimentally measured linewidths and their impact on planetary atmosphere research are discussed. Experimental techniques which may have some advantage in providing pressure broadening data at very low temperatures are also mentioned.

  14. New theoretical and experimental methods for pressure broadened linewidths and their interpretation

    NASA Technical Reports Server (NTRS)

    Gelfand, J. J.

    1982-01-01

    A review of recent progress in the theory of collisional line broadening, particularly the impact of recent advances in collision dynamics calculations is presented. Some new approaches to the interpretation of experimentally measured linewidths and their impact on planetary atmosphere research are discussed. Experimental techniques which may have some advantage in providing pressure broadening data at very low temperatures are also mentioned.

  15. Cone penetration and bevameter geotechnical tests in lunar regolith simulants: discrete element method analysis and experimentation

    NASA Astrophysics Data System (ADS)

    Kulchitsky, A. V.; Johnson, J.; Duvoy, P.; Wilkinson, A.; Creager, C. M.

    2012-12-01

    For in situ resource utilization on the Moon, asteroids, Mars, or other space body it is necessary to be able to simulate the interaction of mobile platforms and excavation machines with the regolith for engineering design, planning, and operations. For accurate simulations, tools designed to measure regolith properties will need to be deployed and interpreted. Two such tools are the penetrometer, used to measure a soil strength index as a function of depth, and the bevameter, used to characterize regolith surface properties of strength, friction and sinkage. The penetrometer interrogates regolith properties from the surface to a depth limited only by the capabilities of the instrument to penetrate the regolith while a bevameter interrogates only the upper few centimeters needed to describe a mobility platform's traction and sinkage. Interpretation of penetrometer and bevameter data can be difficult, especially on low gravity objects. We use the discrete element method (DEM) model to simulate the large regolith deformations and failures associated with the tests to determine regolith properties. The DEM simulates granular material behavior using large aggregates of distinct particles. Realistic physics of particle-particle interaction introduces many granular specific phenomena such as interlocking and force chain formation that cannot be represented using continuum methods. In this work, experiments using a cone penetrometer test (CPT) and bevameter on lunar simulants JSC-1A and GRC-1 were performed at NASA Glenn Research Center. These tests were used to validate the physics in the COUPi DEM model. COUPi is a general physical DEM code being developed to model machine/regolith interactions as part of a NASA Lunar Science Institute sponsored project on excavation and mobility modeling. The experimental results were used in this work to build an accurate model to simulate the lunar regolith. The CPT consists of driving an instrumented cone with opening angle of 60

  16. Increasing active travel: aims, methods and baseline measures of a quasi-experimental study.

    PubMed

    Chapman, Ralph; Howden-Chapman, Philippa; Keall, Michael; Witten, Karen; Abrahamse, Wokje; Woodward, Alistair; Muggeridge, Dylan; Beetham, Jean; Grams, Mark

    2014-09-08

    Policy advisers are seeking robust evidence on the effectiveness of measures, such as promoting walking and cycling, that potentially offer multiple benefits, including enhanced health through physical activity, alongside reductions in energy use, traffic congestion and carbon emissions. This paper outlines the 'ACTIVE' study, designed to test whether the Model Communities Programme in two New Zealand cities is increasing walking and cycling. The intervention consists of the introduction of cycle and walkway infrastructure, along with measures to encourage active travel. This paper focuses on the rationale for our chosen study design and methods. The study design is multi-level and quasi-experimental, with two intervention and two control cities. Baseline measures were taken in 2011 and follow-up measures in 2012 and 2013. Our face-to-face surveys measured walking and cycling, but also awareness, attitudes and habits. We measured explanatory and confounding factors for mode choice, including socio-demographic and well-being variables. Data collected from the same households on either two or three occasions will be analysed using multi-level models that take account of clustering at the household and individual levels. A cost-benefit analysis will also be undertaken, using our estimates of carbon savings from mode shifts. The matching of the intervention and control cities was quite close in terms of socio-demographic variables, including ethnicity, and baseline levels of walking and cycling. This multidisciplinary study provides a strong design for evaluating an intervention to increase walking and cycling in a developed country with relatively low baseline levels of active travel. Its strengths include the use of data from control cities as well as intervention cities, an extended evaluation period with a reasonable response rate from a random community survey and the availability of instrumental variables for sensitivity analyses.

  17. The factorial survey: an experimental method to replicate real world problems.

    PubMed

    Ludwick, R; Zeller, R A

    2001-01-01

    Vignettes are used by nurse researchers use to determine how clinical judgments about patient care situations are made. However, when vignettes are designed there is often a restriction on the number of characteristics studied, which oversimplifies the richness and complexity of real world healthcare situations. The purpose of this article is to describe a factorial survey. Its multilevel design of independent variables allows for real world complexity in a way not tested by a sample set of four to six identical vignettes. Nurses' judgments about patients' confusion and the application of restraints are used to illustrate the method. The factorial survey is an experimental design that can be developed in three steps: (a) identifying and using the variables, (b) writing a coherent vignette, and (c) randomly generating the vignettes. The unit of analysis is the vignette and Ordinary Least Squares (OLS) regression is used for analyses. In the example provided on confusion recognition and restraint use, patient characteristics accounted for the majority of explained variance in confusion recognition of (40%, R2 = 0.40) and restraint intervention for (43%, R2 = 0.43). The results for both models were strikingly similar as the same patient characteristics all were significant predictors for confusion recognition and restraint use. The versatility of the factorial survey lies in the researcher's ability to use it to test judgments in a variety of complex clinical simulations, to aid in concept development, and to identify consensus and disagreement among nurses. The multilevel design of the independent variables allows for real world complexity in a way not tested by a sample set of four to six identical vignettes.

  18. A method of fast, sequential experimental design for linearized geophysical inverse problems

    NASA Astrophysics Data System (ADS)

    Coles, Darrell A.; Morgan, Frank Dale

    2009-07-01

    An algorithm for linear(ized) experimental design is developed for a determinant-based design objective function. This objective function is common in design theory and is used to design experiments that minimize the model entropy, a measure of posterior model uncertainty. Of primary significance in design problems is computational expediency. Several earlier papers have focused attention on posing design objective functions and opted to use global search methods for finding the critical points of these functions, but these algorithms are too slow to be practical. The proposed technique is distinguished primarily for its computational efficiency, which derives partly from a greedy optimization approach, termed sequential design. Computational efficiency is further enhanced through formulae for updating determinants and matrix inverses without need for direct calculation. The design approach is orders of magnitude faster than a genetic algorithm applied to the same design problem. However, greedy optimization often trades global optimality for increased computational speed; the ramifications of this tradeoff are discussed. The design methodology is demonstrated on a simple, single-borehole DC electrical resistivity problem. Designed surveys are compared with random and standard surveys, both with and without prior information. All surveys were compared with respect to a `relative quality' measure, the post-inversion model per cent rms error. The issue of design for inherently ill-posed inverse problems is considered and an approach for circumventing such problems is proposed. The design algorithm is also applied in an adaptive manner, with excellent results suggesting that smart, compact experiments can be designed in real time.

  19. Experimental evaluation of neural probe’s insertion induced injury based on digital image correlation method

    SciTech Connect

    Zhang, Wenguang Ma, Yakun; Li, Zhengwei

    2016-01-15

    Purpose: The application of neural probes in clinic has been challenged by probes’ short lifetime when implanted into brain tissue. The primary goal is to develop an evaluation system for testing brain tissue injury induced by neural probe’s insertion using microscope based digital image correlation method. Methods: A brain tissue phantom made of silicone rubber with speckle pattern on its surface was fabricated. To obtain the optimal speckle pattern, mean intensity gradient parameter was used for quality assessment. The designed testing system consists of three modules: (a) load module for simulating neural electrode implantation process; (b) data acquisition module to capture micrographs of speckle pattern and to obtain reactive forces during the insertion of the probe; (c) postprocessing module for extracting tissue deformation information from the captured speckle patterns. On the basis of the evaluation system, the effects of probe wedge angle, insertion speed, and probe streamline on insertion induced tissue injury were investigated. Results: The optimal quality speckle pattern can be attained by the following fabrication parameters: spin coating rate—1000 r/min, silicone rubber component A: silicone rubber component B: softener: graphite = 5 ml: 5 ml: 2 ml: 0.6 g. The probe wedge angle has a significant effect on tissue injury. Compared to wedge angle 40° and 20°, maximum principal strain of 60° wedge angle was increased by 40.3% and 87.5%, respectively; compared with a relatively higher speed (500 μm/s), the maximum principle strain within the tissue induced by slow insertion speed (100 μm/s) was increased by 14.3%; insertion force required by probe with convex streamline was smaller than the force of traditional probe. Based on the experimental results, a novel neural probe that has a rounded tip covered by a biodegradable silk protein coating with convex streamline was proposed, which has both lower insertion and micromotion induced tissue

  20. An experimental investigation by optical methods of the physics and chemistry of transient plasma ignition

    NASA Astrophysics Data System (ADS)

    Pendleton, Scott James

    The use of nonequilibrium plasma generated by nanosecond discharges to ignite fuel/air mixtures, known as transient plasma ignition (TPI), has been shown to effectively reduce ignition delay and improve engine performance relative to spark ignition for combustion engines. While this method is potentially useful for many engine applications, at present the underlying physics are poorly understood. This work provides a review of previous engine implementation work as well as previous experimental work seeking to provide an understanding of the physical and chemical mechanisms of TPI. Work on producing the pulses needed for TPI, both engine testing and optical diagnostic is presented. The emission of TPI is analyzed in order to determine the spectral, spatial, and temporal behavior of the discharge. Temperature mesurements of TPI using optical emission spectroscopy (OES) show that the temperature in streamer discharge and afterglow increases, though it is difficult to quantify the increase with this method. The results of coherent anti-Stokes Raman spectroscopy temperature measurements are reported and discussed, with temperature increases up to 1500 K above ambient observed in the discharge afterglow in fuel/air mixtures. The impact of this temperature increase on TPI and the possibility of thermal ignition is considered. In addition, CARS measurements show that generation of vibrationally excited states of nitrogen is inefficient during the discharge in air but that generation occurs at a high rate roughly 5 micros following the discharge; with the addition of fuels vibrationally excited states are observed during the discharge but an increase in population is still seen at 5 micros. Possible mechanisms for this behavior are discussed. Additionally, this work uses two-photon absorption laser induced fluorescence to measure oxygen atom concentrations in streamer discharge afterglow in a variety of fuel/air mixtures in order to account for the oxygen pathways in

  1. Parameter estimation and uncertainty quantification in a biogeochemical model using optimal experimental design methods

    NASA Astrophysics Data System (ADS)

    Reimer, Joscha; Piwonski, Jaroslaw; Slawig, Thomas

    2016-04-01

    The statistical significance of any model-data comparison strongly depends on the quality of the used data and the criterion used to measure the model-to-data misfit. The statistical properties (such as mean values, variances and covariances) of the data should be taken into account by choosing a criterion as, e.g., ordinary, weighted or generalized least squares. Moreover, the criterion can be restricted onto regions or model quantities which are of special interest. This choice influences the quality of the model output (also for not measured quantities) and the results of a parameter estimation or optimization process. We have estimated the parameters of a three-dimensional and time-dependent marine biogeochemical model describing the phosphorus cycle in the ocean. For this purpose, we have developed a statistical model for measurements of phosphate and dissolved organic phosphorus. This statistical model includes variances and correlations varying with time and location of the measurements. We compared the obtained estimations of model output and parameters for different criteria. Another question is if (and which) further measurements would increase the model's quality at all. Using experimental design criteria, the information content of measurements can be quantified. This may refer to the uncertainty in unknown model parameters as well as the uncertainty regarding which model is closer to reality. By (another) optimization, optimal measurement properties such as locations, time instants and quantities to be measured can be identified. We have optimized such properties for additional measurement for the parameter estimation of the marine biogeochemical model. For this purpose, we have quantified the uncertainty in the optimal model parameters and the model output itself regarding the uncertainty in the measurement data using the (Fisher) information matrix. Furthermore, we have calculated the uncertainty reduction by additional measurements depending on time

  2. Exploring the interplay between experimental methods and the performance of predictors of binding affinity change upon mutations in protein complexes.

    PubMed

    Geng, Cunliang; Vangone, Anna; Bonvin, Alexandre M J J

    2016-08-01

    Reliable prediction of binding affinity changes (ΔΔG) upon mutations in protein complexes relies not only on the performance of computational methods but also on the availability and quality of experimental data. Binding affinity changes can be measured by various experimental methods with different accuracies and limitations. To understand the impact of these on the prediction of binding affinity change, we present the Database of binding Affinity Change Upon Mutation (DACUM), a database of 1872 binding affinity changes upon single-point mutations, a subset of the SKEMPI database (Moal,I.H. and Fernández-Recio,J. Bioinformatics, 2012;28:2600-2607) extended with information on the experimental methods used for ΔΔG measurements. The ΔΔG data were classified into different data sets based on the experimental method used and the position of the mutation (interface and non-interface). We tested the prediction performance of the original HADDOCK score, a newly trained version of it and mutation Cutoff Scanning Matrix (Pires,D.E.V., Ascher,D.B. and Blundell,T.L. Bioinformatics 2014;30:335-342), one of the best reported ΔΔG predictors so far, on these various data sets. Our results demonstrate a strong impact of the experimental methods on the performance of binding affinity change predictors for protein complexes. This underscores the importance of properly considering and carefully choosing experimental methods in the development of novel binding affinity change predictors. The DACUM database is available online at https://github.com/haddocking/DACUM.

  3. Maguelone (Languedoc coastline, France) : a shallow experimental site for CO2 storage hydrogeophysical monitoring methods.

    NASA Astrophysics Data System (ADS)

    Pezard, Philippe; Denchik, Nataliya; Lofi, Johanna; Perroud, Hervé; Neyens, Denis

    2010-05-01

    The Maguelone experimental site is located along the Mediterranean lido of the Gulf of Lions passive margin, 10 km south from Montpellier. Limited to the north by a coastal lagoon and to the south by the Mediterranean sea, this site offers a natural laboratory to study porous coastal reservoirs in a clastic and clay-rich context saturated with mostly saline fluids. Drilled and cored in 2003 for sedimentological purpose, the Maguelone site crosses from surface to 9 m depth a thin Holocene sequence constituted with lagoonal sediments made mostly of dark green clays. This sequence forms an impermeable seal overlying unconformably a Pliocene sequence consisting mainly of relatively homogeneous fine grained continental deposits (clays, silts, and clayey silts). The clayey fraction is relatively high all along, making those deposits poorly permeable. In this sequence, a single remarkable depositional unit located from 14 to 17 m, consists of porous and permeable conglomerates and sands interpreted as fluvial deposits. Sedimentary and geophysical measurements suggest a high permeability for this 3 m-thick reservoir. Hydrogen sulphite (H2S) (possibly resulting from lagoonal organic matter decomposition and compaction) encountered during coring operations near 15 m depth confirmed the presence of a small reservoir at this depth. As part of the ALIANCE EC project (FP5), a new downhole resistivity observatory prototype was constructed and set-up in 2004, tested in a dipole-dipole mode, and calibrated against induction resistivity logs. From this, time lapse measurements were emplaced and made automatic showing gradual changes over time in electrical resistivity. Taking advantage of this shallow and thin reservoir embedded in clays and silts, a new shallow experimental site is to be developed in the context of MUSTANG EC project (FP7). In particular, the downhole technology jointly developed by "Géosciences Montpellier" and "imaGeau" is to be adapted to resist the aggressive

  4. Comparison of predicted extinction coefficients of monoclonal antibodies with experimental values as measured by the Edelhoch method.

    PubMed

    Maity, Haripada; Wei, Alex; Chen, Ethan; Haidar, Jaafar N; Srivastava, Arvind; Goldstein, Joel

    2015-01-01

    Pace et al. (1995) [1] recommended an equation used to predict extinction coefficient of a protein. However, no antibody data was included in the development of this equation. The main objective of this study was to therefore investigate how the predicted value of the extinction coefficient is comparable to the experimentally determined extinction coefficient of antibodies measured by the Edelhoch method. We have measured the extinction coefficients (ɛ) of 13 IgG1 monoclonal antibodies (mAbs) in phosphate buffer at pH 7.2. The maximum variability in the experimentally measured extinction coefficient of a given mAb molecule was found to be about 2%. Experimentally determined extinction coefficients of all mAbs were found to be lower than the predicted value, with the maximum difference found to being 4.7%. The highest and lowest values of experimental extinction coefficient among the thirteen IgG1 monoclonal antibodies obtained were 230525.9M(-1)cm(-1) (i.e. 1.55(mg/ml)(-1)cm(-1)) and 191,411.6M(-1)cm(-1) (i.e. 1.29(mg/ml)(-1)cm(-1)). A difference of <3% (with respect to mean value) was observed between the experimental and predicted values of the extinction coefficient. A comprehensive analysis and interpretation of the comparison of the predicted and experimentally determined extinction coefficient by the Edelhoch method is discussed in terms of structural characterization and accessible surface area (ASA).

  5. Plant Disease Severity Assessment-How Rater Bias, Assessment Method, and Experimental Design Affect Hypothesis Testing and Resource Use Efficiency.

    PubMed

    Chiang, Kuo-Szu; Bock, Clive H; Lee, I-Hsuan; El Jarroudi, Moussa; Delfosse, Philippe

    2016-12-01

    The effect of rater bias and assessment method on hypothesis testing was studied for representative experimental designs for plant disease assessment using balanced and unbalanced data sets. Data sets with the same number of replicate estimates for each of two treatments are termed "balanced" and those with unequal numbers of replicate estimates are termed "unbalanced". The three assessment methods considered were nearest percent estimates (NPEs), an amended 10% incremental scale, and the Horsfall-Barratt (H-B) scale. Estimates of severity of Septoria leaf blotch on leaves of winter wheat were used to develop distributions for a simulation model. The experimental designs are presented here in the context of simulation experiments which consider the optimal design for the number of specimens (individual units sampled) and the number of replicate estimates per specimen for a fixed total number of observations (total sample size for the treatments being compared). The criterion used to gauge each method was the power of the hypothesis test. As expected, at a given fixed number of observations, the balanced experimental designs invariably resulted in a higher power compared with the unbalanced designs at different disease severity means, mean differences, and variances. Based on these results, with unbiased estimates using NPE, the recommended number of replicate estimates taken per specimen is 2 (from a sample of specimens of at least 30), because this conserves resources. Furthermore, for biased estimates, an apparent difference in the power of the hypothesis test was observed between assessment methods and between experimental designs. Results indicated that, regardless of experimental design or rater bias, an amended 10% incremental scale has slightly less power compared with NPEs, and that the H-B scale is more likely than the others to cause a type II error. These results suggest that choice of assessment method, optimizing sample number and number of replicate

  6. An Automated, Experimenter-Free Method for the Standardised, Operant Cognitive Testing of Rats

    PubMed Central

    Rivalan, Marion; Munawar, Humaira; Fuchs, Anna; Winter, York

    2017-01-01

    Animal models of human pathology are essential for biomedical research. However, a recurring issue in the use of animal models is the poor reproducibility of behavioural and physiological findings within and between laboratories. The most critical factor influencing this issue remains the experimenter themselves. One solution is the use of procedures devoid of human intervention. We present a novel approach to experimenter-free testing cognitive abilities in rats, by combining undisturbed group housing with automated, standardized and individual operant testing. This experimenter-free system consisted of an automated-operant system (Bussey-Saksida rat touch screen) connected to a home cage containing group living rats via an automated animal sorter (PhenoSys). The automated animal sorter, which is based on radio-frequency identification (RFID) technology, functioned as a mechanical replacement of the experimenter. Rats learnt to regularly and individually enter the operant chamber and remained there for the duration of the experimental session only. Self-motivated rats acquired the complex touch screen task of trial-unique non-matching to location (TUNL) in half the time reported for animals that were manually placed into the operant chamber. Rat performance was similar between the two groups within our laboratory, and comparable to previously published results obtained elsewhere. This reproducibility, both within and between laboratories, confirms the validity of this approach. In addition, automation reduced daily experimental time by 80%, eliminated animal handling, and reduced equipment cost. This automated, experimenter-free setup is a promising tool of great potential for testing a large variety of functions with full automation in future studies. PMID:28060883

  7. Foot-and-Mouth Disease in Red Deer - Experimental Infection and Test Methods Performance.

    PubMed

    Kittelberger, R; Nfon, C; Swekla, K; Zhang, Z; Hole, K; Bittner, H; Salo, T; Goolia, M; Embury-Hyatt, C; Bueno, R; Hannah, M; Swainsbury, R; O'Sullivan, C; Spence, R; Clough, R; McFadden, A; Rawdon, T; Alexandersen, S

    2017-02-01

    The aim of this study was to evaluate a number of foot-and-mouth disease (FMD) test methods for use in red deer. Ten animals were intranasally inoculated with the FMD virus (FMDV) O UKG 11/2001, monitored for clinical signs, and samples taken regularly (blood, serum, oral swabs, nasal swabs, probang samples and lesion swabs, if present) over a 4-week period. Only one animal, deer 1103, developed clinical signs (lesions under the tongue and at the coronary band of the right hind hoof). It tested positive by 3D and IRES real-time reverse transcription polymerase chain reaction (rRT-PCR) in various swabs, lesion materials and serum. In a non-structural protein (NSP) in-house ELISA (NSP-ELISA-IH), one commercial ELISA (NSP-ELISA-PR) and a commercial antibody NSP pen side test, only deer 1103 showed positive results from day post-inoculation (dpi) 14 onwards. Two other NSP-ELISAs detected anti-NSP serum antibodies with lower sensitivity. It also showed rising antibody levels in the virus neutralization test (VNT), the in-house SPO-ELISA-IH and the commercial SPO-ELISA-PR at dpi 9, and in another two commercial SPO-ELISAs at dpi 12 (SPO-ELISA-IV) and dpi 19 (SPO-ELISA-IZ), respectively. Six of the red deer that had been rRT-PCR and antibody negative were re-inoculated intramuscularly with the same O-serotype FMDV at dpi 14. None of these animals became rRT-PCR or NSP-ELISA positive, but all six animals became positive in the VNT, the in-house SPO-ELISA-IH and the commercial SPO-ELISA-PR. Two other commercial SPO-ELISAs were less sensitive or failed to detect animals as positive. The rRT-PCRs and the four most sensitive commercial ELISAs that had been used for the experimentally inoculated deer were further evaluated for diagnostic specificity (DSP) using 950 serum samples and 200 nasal swabs from non-infected animals. DSPs were 100% for the rRT-PCRs and between 99.8 and 100% for the ELISAs.

  8. An Experimental Simulation Method of Erosion Process on Gully Erosion in Loess Plateau in China

    NASA Astrophysics Data System (ADS)

    Gao, Jianen; Zhang, Yuanxing

    2017-04-01

    In view of simulation difficultment of the field gully erosion process because of complex of rainfall runoff erosion mechanism and gully geometry a design means and experimentation technology and its verification test were given based on similarity theory and hydrodynamic principles. The basic ideas was that the erosion process of the field erosion gully was forecast by constructing similar model. The model and antetype should be in obedience to the same physical equations of rainfall, runoff, erosion, sediment transport, bed deformation and Soil water transport. The geometric, kinematical and dynamic similarity must be obeyed for these models. The primary similarity scale relation expressions were the ones of the geometric, rainfall, flow, erosion sediment transport and soil water movement similarity etc. The similarity of the hydraulic boundary was the necessary and sufficient condition between the model and the prototype. The gully prototype is one of Majiagou of Ansai county of Yanan City of Shaanxi Province in China. Its location is 36°53'55.75"N and 109°13'39.08"E. The model experiment wan carried out in State Key Laboratory of Soil Erosion and Dry land Farming On the Loess Plateau in Institute of Soil and Water Conservation of Northwest A&F University. First soil was selected by starting velocity similar. Second, the normal and scale 10 experiment model was built under complying with the similarities of geometric, rainfall, flow, erosion production sediment transport and bed deformation etc. The model hydraulic boundary from the prototype was the factor of the test process of rainfall. The experiment results indicated that the extreme rainstorm gully erosion process of the prototype could be reappeared. The equivalent rainfall process of gully prototype were that the rainfall intensity was 1.25 mm/min and the lasting time was 508 min and precipitation was 636mmn. Both the erosion amount and the erosion gully topography of the scale model were successfully

  9. [Treatment of bedsores--combination of therapies depended the experimental design method].

    PubMed

    Miyaji, Hiroko; Sakurai, Hirofumi; Kikawada, Masayuki; Yamaguchi, Katsuhiko; Kimura, Akihiro; Fujiwara, Takayuki; Imada, Nobuo; Imai, Mihoko; Iwamoto, Toshihiko; Takasaki, Masaru

    2005-01-01

    The treatment of bedsores is a particular problem in geriatric medicine. We selected standard drugs that may be effective for the decubitus ulcer, and investigated combination therapy to develop efficient treatment The subjects were 16 patients in whom the grade of the bedsore was evaluated as II to IV according to the Shea's depth classification. Treatment was performed while all patients were on air mats. We selected drugs and treatment methods based on the previously established experimental design of Taguchi. Based on this, we created and adapted 16 different component combination treatment programs in accordance with the L16 rectangular cross table. The following component factors were adopted: A: types of covering substances on the wound surface (Elase ointment, isodine sugar, isodine gel solcoseryl ointment); B: Isalopan powder; C: Spray of 10 ml physiological saline containing 500 microg of prostaglandin (concentration 0.005%); D: daily number of treatments; and F: presence or absence of tapping. We serially measured the wound surface area as an index of the speed of wound healing, and measured the interval (day) until the area decreased to one half of the original size (T1/2, half life). We analyzed data on one combination treatment each in 16 patients. Analysis of variance of the above factors showed significant F values for factors A, B, D and F. The contribution rates for factors A, B, D and F were 37.84%, 8.47%, 14.98% and 13.81%, respectively. The error term (e) was 16.37%. Optimal results were seen in the groups in which solcoseryl ointment had been applied twice a day. In this study, prostaglandin, which had been anticipated to be effective, did not show any effects. The error term (e) suggests the presence of other healing factors including individual differences. Concerning this point, it well be necessary to examine a larger number of patients in the future. With ointment treatment alone, without using an air mat, it was confirmed that bedsore

  10. A stochastic method for asphaltene structure formulation from experimental data: avoidance of implausible structures.

    PubMed

    De León, Jennifer; Velásquez, Ana M; Hoyos, Bibian A

    2017-04-12

    This work presents a stochastic procedure designed to formulate a discrete set of molecular structures that, as a whole, adjust properly to experimental asphaltene data. This algorithm incorporates the pentane effect concept and Clar's sextet rule to the formulation process. The set of viable structures was constructed based on probability distribution functions obtained from experimental information and an isomer database containing all plausible configurations for a given number of rings, avoiding high-energy structures. This procedure was applied to a collection of experimental data from the literature. Ten sets, consisting of 5000 structures each, were obtained. Each set was then optimized. For the most accurate representation, four molecules were sufficient to properly reproduce the experimental input. The asphaltene system obtained is consistent with the reported molecular weight, number of aromatic rings and heteroatom content. Molecular dynamic simulations showed that the asphaltene representation adequately reproduced asphaltene aggregation behavior in toluene and n-heptane. In toluene, a single three-molecule aggregate was observed, and the majority of asphaltene molecules remained in a monomeric state. In n-heptane, aggregates containing up to four molecules were observed; both porous and compact aggregates were found. The asphaltene molecular representation obtained, which allows researchers to avoid inappropriate torsions in the molecule, is able to reproduce interplanar distances between aromatic cores of 4 Å or less for the aggregation state, as supported by experimental results.

  11. Integrating computational methods and experimental data for understanding the recognition mechanism and binding affinity of protein-protein complexes.

    PubMed

    Gromiha, M Michael; Yugandhar, K

    2017-09-01

    Protein-protein interactions perform several functions inside the cell. Understanding the recognition mechanism and binding affinity of protein-protein complexes is a challenging problem in experimental and computational biology. In this review, we focus on two aspects (i) understanding the recognition mechanism and (ii) predicting the binding affinity. The first part deals with computational techniques for identifying the binding site residues and the contribution of important interactions for understanding the recognition mechanism of protein-protein complexes in comparison with experimental observations. The second part is devoted to the methods developed for discriminating high and low affinity complexes, and predicting the binding affinity of protein-protein complexes using three-dimensional structural information and just from the amino acid sequence. The overall view enhances our understanding of the integration of experimental data and computational methods, recognition mechanism of protein-protein complexes and the binding affinity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Much Pain, Little Gain? Paradigm-Specific Models and Methods in Experimental Psychology.

    PubMed

    Meiser, Thorsten

    2011-03-01

    Paradigm-oriented research strategies in experimental psychology have strengths and limitations. On the one hand, experimental paradigms play a crucial epistemic and heuristic role in basic psychological research. On the other hand, empirical research is often limited to the observed effects in a certain paradigm, and theoretical models are frequently tied to the particular features of the given paradigm. A paradigm-driven research strategy therefore jeopardizes the pursuit of research questions and theoretical models that go beyond a specific paradigm. As one example of a more integrative approach, recent research on illusory and spurious correlations has attempted to overcome the limitations of paradigm-specific models in the context of biased contingency perception and social stereotyping. Last but not least, the use of statistical models for the analysis of elementary cognitive functions is a means toward a more integrative terminology and theoretical perspective across different experimental paradigms and research domains.

  13. Experimental Verification Of The Osculating Cones Method For Two Waverider Forebodies At Mach 4 and 6

    NASA Technical Reports Server (NTRS)

    Miller, Rolf W.; Argrow, Brian M.; Center, Kenneth B.; Brauckmann, Gregory J.; Rhode, Matthew N.

    1998-01-01

    The NASA Langley Research Center Unitary Plan Wind Tunnel and the 20-Inch Mach 6 Tunnel were used to test two osculating cones waverider models. The Mach-4 and Mach-6 shapes were generated using the interactive design tool WIPAR. WIPAR performance predictions are compared to the experimental results. Vapor screen results for the Mach-4 model at the on- design Mach number provide visual verification that the shock is attached along the entire leading edge, within the limits of observation. WIPAR predictions of pressure distributions and aerodynamic coefficients show general agreement with the corresponding experimental values.

  14. Application of a panel method to wake-vortex/wing interaction and comparison with experimental data

    NASA Technical Reports Server (NTRS)

    Smith, Brian E.; Ross, James C.

    1987-01-01

    The ability of the Vortex Separation AEROdynamics (VSAERO) program to calculate aerodynamic loads on wings due to interaction with free vortices was studied. The loads were calculated for various positions of a downstream following wing relative to an upstream vortex-generating wing. Calculated vortex-induced span loads, rolling-moment coefficients, and lift coefficients on the following wing were compared with experimental results of McMillan et al. and El-Ramly et al. Comparisons of calculated and experimental vortex tangential velocities were also made.

  15. Experimental micro mechanics methods for conventional and negative Poisson's ratio cellular solids as Cosserat continua

    NASA Technical Reports Server (NTRS)

    Lakes, R.

    1991-01-01

    Continuum representations of micromechanical phenomena in structured materials are described, with emphasis on cellular solids. These phenomena are interpreted in light of Cosserat elasticity, a generalized continuum theory which admits degrees of freedom not present in classical elasticity. These are the rotation of points in the material, and a couple per unit area or couple stress. Experimental work in this area is reviewed, and other interpretation schemes are discussed. The applicability of Cosserat elasticity to cellular solids and fibrous composite materials is considered as is the application of related generalized continuum theories. New experimental results are presented for foam materials with negative Poisson's ratios.

  16. Experimental micro mechanics methods for conventional and negative Poisson's ratio cellular solids as Cosserat continua

    NASA Technical Reports Server (NTRS)

    Lakes, R.

    1991-01-01

    Continuum representations of micromechanical phenomena in structured materials are described, with emphasis on cellular solids. These phenomena are interpreted in light of Cosserat elasticity, a generalized continuum theory which admits degrees of freedom not present in classical elasticity. These are the rotation of points in the material, and a couple per unit area or couple stress. Experimental work in this area is reviewed, and other interpretation schemes are discussed. The applicability of Cosserat elasticity to cellular solids and fibrous composite materials is considered as is the application of related generalized continuum theories. New experimental results are presented for foam materials with negative Poisson's ratios.

  17. Laser generation of Lamb waves for defect detection: experimental methods and finite element modeling.

    PubMed

    Burrows, Susan E; Dutton, Ben; Dixon, Steve

    2012-01-01

    The propagation of Lamb waves generated by a pulsed laser beam in an aluminum sheet is modeled using finite element analysis, and the interaction with defects is studied and compared to experimental results. The ultrasonic Lamb waves are detected by an electromagnetic acoustic transducer (EMAT). The frequency content of the received wave is shown to be enhanced when the generation point is situated directly over the defect in both the modeled and experimental cases. Time-frequency analysis using a Wigner transform has enabled individual modes to be identified.

  18. Does Comparing Solution Methods Facilitate Conceptual and Procedural Knowledge? An Experimental Study on Learning to Solve Equations

    ERIC Educational Resources Information Center

    Rittle-Johnson, Bethany; Star, Jon R.

    2007-01-01

    Encouraging students to share and compare solution methods is a key component of reform efforts in mathematics, and comparison is emerging as a fundamental learning mechanism. To experimentally evaluate the effects of comparison for mathematics learning, the authors randomly assigned 70 seventh-grade students to learn about algebra equation…

  19. Preliminary analysis of problem of determining experimental performance of air-cooled turbine III : methods for determining power and efficiency

    NASA Technical Reports Server (NTRS)

    Ellerbrock, Herman H , Jr; Ziemer, Robert R

    1950-01-01

    Suggested formula are given for determining air-cooled turbine-performance characteristics, such as power and efficiency, as functions of certain parameters. These functions, generally being unknown, are determined from experimental data obtained from specific investigations. Special plotting methods for isolating the effect of each parameter are outlined.

  20. Experimental Method Development for Estimating Solid-phase Diffusion Coefficients and Material/Air Partition Coefficients of SVOCs

    EPA Science Inventory

    The solid-phase diffusion coefficient (Dm) and material-air partition coefficient (Kma) are key parameters for characterizing the sources and transport of semivolatile organic compounds (SVOCs) in the indoor environment. In this work, a new experimental method was developed to es...

  1. A Comparative Analysis of Ultrasound Velocity in Binary Liquid Systems of PPG by Mathematical and Experimental Methods

    NASA Astrophysics Data System (ADS)

    Gayathri, A.; Venugopal, T.; Venkatramanan, K.

    The estimation of the speed of ultrasound is the fundamental requirement for investigating the transport properties of liquid and solid systems. Ultrasonic velocities of liquid mixtures containing polar and non-polar groups are of considerable importance in understanding inter-molecular interaction between component molecules and they find applications in several industrial and technological processes. There are many standard mathematical methods available to measure the ultrasonic velocity. In the present study, interferometric technique is planned for experimental measurement of ultrasound velocity. In this paper, the speed of ultrasound waves in Polypropylene Glycol (PPG 400, PPG 4000) in toluene has been estimated for different concentrations (2%, 4%, 6%, 8% & 10%) at 303K and these experimental values compared with theoretical values obtained by using various mathematical methods like Nomotto's Relation, Vandeal Vangeal Relation, Impedance Relation, and Rao's specific sound velocity. The most reliable method that matches with experimental method is identified using Average Percentage Error (APE) and analysed in the light of molecular interactions occurring in the binary liquid systems. Comparison of evaluated theoretical velocities with experimental values will reveal the nature of interaction between component molecules in the mixtures. Such theoretical study is useful in defining a comprehensive theoretical model for a specific liquid mixture. Also, various molecular interaction parameters like free volume, internal pressure, viscous relaxation time, inter atomic free length, etc are calculated and discussed in terms of polymer-solvent interactions.

  2. Does Comparing Solution Methods Facilitate Conceptual and Procedural Knowledge? An Experimental Study on Learning to Solve Equations

    ERIC Educational Resources Information Center

    Rittle-Johnson, Bethany; Star, Jon R.

    2007-01-01

    Encouraging students to share and compare solution methods is a key component of reform efforts in mathematics, and comparison is emerging as a fundamental learning mechanism. To experimentally evaluate the effects of comparison for mathematics learning, the authors randomly assigned 70 seventh-grade students to learn about algebra equation…

  3. Plant disease severity assessment - How rater bias, assessment method and experimental design affect hypothesis testing and resource use efficiency

    USDA-ARS?s Scientific Manuscript database

    The impact of rater bias and assessment method on hypothesis testing was studied for different experimental designs for plant disease assessment using balanced and unbalanced data sets. Data sets with the same number of replicate estimates for each of two treatments are termed ‘balanced’, and those ...

  4. Experimental Method Development for Estimating Solid-phase Diffusion Coefficients and Material/Air Partition Coefficients of SVOCs

    EPA Science Inventory

    The solid-phase diffusion coefficient (Dm) and material-air partition coefficient (Kma) are key parameters for characterizing the sources and transport of semivolatile organic compounds (SVOCs) in the indoor environment. In this work, a new experimental method was developed to es...

  5. Evaluating Propensity Score Methods in a Quasi-Experimental Study of the Impact of Menu-Labeling

    PubMed Central

    Mayne, Stephanie L.; Lee, Brian K.; Auchincloss, Amy H.

    2015-01-01

    Background Quasi-experimental studies of menu labeling have found mixed results for improving diet. Differences between experimental groups can hinder interpretation. Propensity scores are an increasingly common method to improve covariate balance, but multiple methods exist and the improvements associated with each method have rarely been compared. In this re-analysis of the impact of menu labeling, we compare multiple propensity score methods to determine which methods optimize balance between experimental groups. Methods Study participants included adult customers who visited full-service restaurants with menu labeling (treatment) and without (control). We compared the balance between treatment groups obtained by four propensity score methods: 1) 1:1 nearest neighbor matching (NN), 2) augmented 1:1 NN (using caliper of 0.2 and an exact match on an imbalanced covariate), 3) full matching, and 4) inverse probability weighting (IPW). We then evaluated the treatment effect on differences in nutrients purchased across the different methods. Results 1:1 NN resulted in worse balance than the original unmatched sample (average standardized absolute mean distance [ASAM]: 0.185 compared to 0.171). Augmented 1:1 NN improved balance (ASAM: 0.038) but resulted in a large reduction in sample size. Full matching and IPW improved balance over the unmatched sample without a reduction in sample size (ASAM: 0.049 and 0.031, respectively). Menu labeling was associated with decreased calories, fat, sodium and carbohydrates in the unmatched analysis. Results were qualitatively similar in the propensity score matched/weighted models. Conclusions While propensity scores offer an increasingly popular tool to improve causal inference, choosing the correct method can be challenging. Our results emphasize the benefit of examining multiple methods to ensure results are consistent, and considering approaches beyond the most popular method of 1:1 NN matching. PMID:26677849

  6. Guided-Inquiry Labs Using Bean Beetles for Teaching the Scientific Method & Experimental Design

    ERIC Educational Resources Information Center

    Schlueter, Mark A.; D'Costa, Allison R.

    2013-01-01

    Guided-inquiry lab activities with bean beetles ("Callosobruchus maculatus") teach students how to develop hypotheses, design experiments, identify experimental variables, collect and interpret data, and formulate conclusions. These activities provide students with real hands-on experiences and skills that reinforce their understanding of the…

  7. Return to Our Roots: Raising Radishes to Teach Experimental Design. Methods and Techniques.

    ERIC Educational Resources Information Center

    Stallings, William M.

    1993-01-01

    Reviews research in teaching applied statistics. Concludes that students should analyze data from studies they have designed and conducted. Describes an activity in which students study germination and growth of radish seeds. Includes a table providing student instructions for both the experimental procedure and data analysis. (CFR)

  8. Experimental Design and Methods for Development of Diagnostic Assays for Schistosomiasis Using Monoclonal Antibodies.

    DTIC Science & Technology

    1983-08-25

    Sera from patients or experimental animals infected with Schistosoma, Fasciola hepatica , Trichinella spiralis, Taenia solium, Echinococcus...infection with T. spiralis (18) or F. hepatica (19), or after immunization with isolated F. hepatica antigens (2023) or P. westermani antigens (17) have a...significantly reduced S. mansoni worm burden: Conversely, mice infected with S. mansoni for over 28 days significantly resisted an F. hepatica

  9. Return to Our Roots: Raising Radishes to Teach Experimental Design. Methods and Techniques.

    ERIC Educational Resources Information Center

    Stallings, William M.

    1993-01-01

    Reviews research in teaching applied statistics. Concludes that students should analyze data from studies they have designed and conducted. Describes an activity in which students study germination and growth of radish seeds. Includes a table providing student instructions for both the experimental procedure and data analysis. (CFR)

  10. Comparison of Breast Health Teaching Methods for Adolescent Females: Results of a Quasi-Experimental Study

    ERIC Educational Resources Information Center

    Evans, Retta R.; Horton, Jacqueline A.; Ahmad, Wajih A.; Davies, Susan L.; Snyder, Scott W.; Macrina, David M.

    2013-01-01

    Purpose: A breast health educational program was administered in two public high school settings in north Alabama to subjects enrolled in health related courses. The purpose of this quasi-experimental study was to determine if teaching breast health with or without interactive learning would affect the breast health knowledge and beliefs of…

  11. Instream-Flow Analysis for the Luquillo Experimental Forest, Puerto Rico: Methods and Analysis

    Treesearch

    F.N. Scatena; S.L. Johnson

    2001-01-01

    This study develops two habitat-based approaches for evaluating instream-flow requirements within the Luquillo Experimental Forest in northeastern Puerto Rico. The analysis is restricted to instream-flow requirements in upland streams dominated by the common communities of freshwater decapods. In headwater streams, pool volume was the most consistent factor...

  12. Guided-Inquiry Labs Using Bean Beetles for Teaching the Scientific Method & Experimental Design

    ERIC Educational Resources Information Center

    Schlueter, Mark A.; D'Costa, Allison R.

    2013-01-01

    Guided-inquiry lab activities with bean beetles ("Callosobruchus maculatus") teach students how to develop hypotheses, design experiments, identify experimental variables, collect and interpret data, and formulate conclusions. These activities provide students with real hands-on experiences and skills that reinforce their understanding of the…

  13. Adsorption of benzaldehyde at the surface of ice, studied by experimental method and computer simulation.

    PubMed

    Petitjean, Mélanie; Hantal, György; Chauvin, Coline; Mirabel, Philippe; Le Calvé, Stéphane; Hoang, Paul N M; Picaud, Sylvain; Jedlovszky, Pál

    2010-06-15

    Adsorption study of benzaldehyde on ice surfaces is performed by combining experimental and theoretical approaches. The experiments are conducted over the temperature range 233-253 K using a coated wall flow tube coupled to a mass spectrometric detector. Besides the experimental way, the adsorption isotherm is also determined by performing a set of grand canonical Monte Carlo simulations at 233 K. The experimental and calculated adsorption isotherms show a very good agreement within the corresponding errors. Besides, both experimental and theoretical studies permit us to derive the enthalpy of adsorption of benzaldehyde on ice surfaces DeltaH(ads), which are in excellent agreement: DeltaH(ads) = -61.4 +/- 9.7 kJ/mol (experimental) and DeltaH(ads) = -59.4 +/- 5.1 kJ/mol (simulation). The obtained results indicate a much stronger ability of benzaldehyde of being adsorbed at the surface of ice than that of small aliphatic aldehydes, such as formaldehyde or acetaldehyde. At low surface coverages the adsorbed molecules exclusively lie parallel with the ice surface. With increasing surface coverage, however, the increasing competition of the adsorbed molecules for the surface area to be occupied leads to the appearance of two different perpendicular orientations relative to the surface. In the first orientation, the benzaldehyde molecule turns its aldehyde group toward the ice phase, and, similarly to the molecules in the lying orientation, forms a hydrogen bond with a surface water molecule. In the other perpendicular orientation the aldehyde group turns to the vapor phase, and its O atom interacts with the delocalized pi system of the benzene ring of a nearby lying benzaldehyde molecule of the second molecular layer. In accordance with this observed scenario, the saturated adsorption layer, being stable in a roughly 1 kJ/mol broad range of chemical potentials, contains, besides the first molecular layer, also traces of the second molecular layer of adsorbed

  14. Experimental study of photon induced gamma emission of hafnium-178(m2) by nuclear spectroscopy methods

    NASA Astrophysics Data System (ADS)

    Zoita, Nicolae Catalin

    The induced release of the energy stored in nuclear isomers in the form of an incoherent gamma burst is of great scientific and technological importance. Powerful sources of induced gamma-ray radiation could be obtained, which would be an intermediary step to the development of a gamma-ray laser. High-energy nuclear isomers with very long lifetimes of the order of years and higher can serve as good active media. For instance, a macroscopic sample of 178Hfm2 isomer stores about 1 GJ/g as excitation energy of the isomeric state. Photonuclear reactions induced by real or virtual photons are the most promising mechanisms to release the energy stored by 178Hfm2 nuclei. The isomeric nucleus is excited to an intermediate level from which cascade to the ground state emitting gamma-photons. The nuclear level density approaches one per keV at those excitation energies. Experimental investigations by nuclear spectroscopy methods conducted in this work revealed that the decay of 178Hfm2 is accelerated when the energies of the incident photons were tuned at about 20,825 keV, 11.15 keV or near the L3 photoionization threshold of atomic hafnium at 9561 keV. In the first case, the presumed mechanism was the direct photoexcitation of the m2 isomeric nucleus to a trigger level at about 2466.9 keV. There was a strong decay branch from this trigger level to the 11- level of the 8 - band that caused the accelerated emission of gamma photons from many of the transitions detected in the unperturbed spontaneous decay. In the second case, a trigger level at about 2457.2 keV, that meant 11.15 keV above the 16+ isomeric level, was mediating the energy release. The direct transition from this level to ground state was observed. Other branches of its decay enhanced the gamma-emission of the ground state band (GSB) members. In the third case, complex electron bridging mechanisms were implied when incident X-ray photons were tuned at energies near the L3 photoionization threshold. Those

  15. Theoretical and experimental comparisons of the nonlinear energy method to the J-integral, R-curve and COD methods in fracture toughness testing

    NASA Technical Reports Server (NTRS)

    Liebowitz, H.; Jones, D. L.; Poulose, P. K.

    1974-01-01

    Because of the current high degree of interest in the development of a standard nonlinear test method, analytical and experimental comparisons have been made between the R-curve, COD, J-integral and nonlinear energy methods. A general definition of fracture toughness is proposed and the fundamental definitions of each method are compared to it. Experimental comparisons between the COD, J-integral, nonlinear energy and standard ASTM methods have been made for a series of compact tension tests on several aluminum alloys. Some of the tests were conducted according to the ASTM standard method E399-72, while the specimen thickness was reduced below the minimum requirement for plane strain fracture toughness testing for several other test series. The fracture toughness values obtained by the COD method were significantly higher than the toughness values obtained by the other three methods. All of the methods displayed a tendency to yield higher toughness values as the thickness was decreased below the ASTM plane strain requirement.

  16. Theoretical and experimental comparisons of the nonlinear energy method to the J-integral, R-curve and COD methods in fracture toughness testing

    NASA Technical Reports Server (NTRS)

    Liebowitz, H.; Jones, D. L.; Poulose, P. K.

    1974-01-01

    Because of the current high degree of interest in the development of a standard nonlinear test method, analytical and experimental comparisons have been made between the R-curve, COD, J-integral and nonlinear energy methods. A general definition of fracture toughness is proposed and the fundamental definitions of each method are compared to it. Experimental comparisons between the COD, J-integral, nonlinear energy and standard ASTM methods have been made for a series of compact tension tests on several aluminum alloys. Some of the tests were conducted according to the ASTM standard method E399-72, while the specimen thickness was reduced below the minimum requirement for plane strain fracture toughness testing for several other test series. The fracture toughness values obtained by the COD method were significantly higher than the toughness values obtained by the other three methods. All of the methods displayed a tendency to yield higher toughness values as the thickness was decreased below the ASTM plane strain requirement.

  17. A hybrid passive localization method under strong interference with a preliminary experimental demonstration

    NASA Astrophysics Data System (ADS)

    Lei, Bo; Yang, Yixin; Yang, Kunde; Wang, Yong; Shi, Yang

    2016-12-01

    Strong interference exists in many passive localization problems and may lead to the inefficacy of traditional localization methods. In this study, a hybrid passive localization method is proposed to address strong interference. This method combines generalized cross-correlation and interference cancellation for time-difference-of-arrival (TDOA) measurement, followed by a time-delay-based iterative localization method. The proposed method is applied to a preliminary experiment using three hydrophones. The TDOAs estimated by the proposed method are compared with those obtained by the particle filtering method. Results show that the positions are in agreement when the TDOAs are accurately obtained. Furthermore, the proposed method is more capable of localization in the presence of a strong moving jamming source.

  18. Graphite furnace atomic absorption spectrophotometry--a novel method to quantify blood volume in experimental models of intracerebral hemorrhage.

    PubMed

    Kashefiolasl, Sepide; Foerch, Christian; Pfeilschifter, Waltraud

    2013-02-15

    Intracerebral hemorrhage (ICH) accounts for 10% of all strokes and has a significantly higher mortality than cerebral ischemia. For decades, ICH has been neglected by experimental stroke researchers. Recently, however, clinical trials on acute blood pressure lowering or hyperacute supplementation of coagulation factors in ICH have spurred an interest to also design and improve translational animal models of spontaneous and anticoagulant-associated ICH. Hematoma volume is a substantial outcome parameter of most experimental ICH studies. We present graphite furnace atomic absorption spectrophotometric analysis (AAS) as a suitable method to precisely quantify hematoma volumes in rodent models of ICH.

  19. A simple method of calculating power-law velocity profile exponents from experimental data. [for boundary layer shape factor

    NASA Technical Reports Server (NTRS)

    Allen, J. M.

    1974-01-01

    Analytical expressions for the effects of compressibility and heat transfer on laminar and turbulent shape factors H have been developed. Solving the turbulent equation for the power law velocity profile exponent N has resulted in a simple technique by which the N values of experimental turbulent profiles can be calculated directly from the integral parameters. Thus the data plotting, curve fitting, and slope measuring, which is the normal technique of obtaining experimental N values, is eliminated. The N values obtained by this method should be within the accuracy with which they could be measured.

  20. A convenient method and numerical tables for sample size determination in longitudinal-experimental research using multilevel models.

    PubMed

    Usami, Satoshi

    2014-12-01

    Recent years have shown increased awareness of the importance of sample size determination in experimental research. Yet effective and convenient methods for sample size determination, especially in longitudinal experimental design, are still under development, and application of power analysis in applied research remains limited. This article presents a convenient method for sample size determination in longitudinal experimental research using a multilevel model. A fundamental idea of this method is transformation of model parameters (level 1 error variance [σ(2)], level 2 error variances [τ 00, τ 11] and its covariance [τ 01, τ 10], and a parameter representing experimental effect [δ]) into indices (reliability of measurement at the first time point [ρ 1], effect size at the last time point [Δ T ], proportion of variance of outcomes between the first and the last time points [k], and level 2 error correlation [r]) that are intuitively understandable and easily specified. To foster more convenient use of power analysis, numerical tables are constructed that refer to ANOVA results to investigate the influence on statistical power by respective indices.

  1. A numerical and experimental comparison of test methods for the shear strength in hybrid metal/thermoplastic-compounds

    NASA Astrophysics Data System (ADS)

    Saborowski, E.; Scholze, M.; Lindner, T.; Lampke, T.

    2017-03-01

    The lap shear test is a common method for determining the interlaminar shear strength of material compounds due to its simplicity with regard to specimen production and experimental realization. However, the obtained results strongly depend on the material pairing and the specimen geometry, which have a significant influence to the stress state within the interface during the experiment. A torsion test method using butt-bonded hollow cylinders seems more appropriate due to the expected more homogeneous shear stress distribution. The aim of this work is to compare both testing methods by experimental and numerical investigations. A comparative study with thermally joined aluminum-polyamide hybrid compounds was performed. The corresponding simulations were carried out with the commercial FE-software Abaqus™, using a user defined material model for the thermoplastic joining partner and the built-in cohesive behavior contact property for modelling interfacial damage.

  2. DETECTORS AND EXPERIMENTAL METHODS: Software alignment of the BESIII main drift chamber using the Kalman Filter method

    NASA Astrophysics Data System (ADS)

    Wang, Ji-Ke; Mao, Ze-Pu; Bian, Jian-Ming; Cao, Guo-Fu; Cao, Xue-Xiang; Chen, Shen-Jian; Deng, Zi-Yan; Fu, Cheng-Dong; Gao, Yuan-Ning; He, Kang-Lin; He, Miao; Hua, Chun-Fei; Huang, Bin; Huang, Xing-Tao; Ji, Xiao-Bin; Li, Fei; Li, Hai-Bo; Li, Wei-Dong; Liang, Yu-Tie; Liu, Chun-Xiu; Liu, Huai-Min; Liu, Suo; Liu, Ying-Jie; Ma, Qiu-Mei; Ma, Xiang; Mao, Ya-Jun; Mo, Xiao-Hu; Pan, Ming-Hua; Pang, Cai-Ying; Ping, Rong-Gang; Qin, Ya-Hong; Qiu, Jin-Fa; Sun, Sheng-Sen; Sun, Yong-Zhao; Wang, Liang-Liang; Wen, Shuo-Pin; Wu, Ling-Hui; Xie, Yu-Guang; Xu, Min; Yan, Liang; You, Zheng-Yun; Yuan, Chang-Zheng; Yuan, Ye; Zhang, Bing-Yun; Zhang, Chang-Chun; Zhang, Jian-Yong; Zhang, Xue-Yao; Zhang, Yao; Zheng, Yang-Heng; Zhu, Ke-Jun; Zhu, Yong-Sheng; Zhu, Zhi-Li; Zou, Jia-Heng

    2009-03-01

    Software alignment is quite important for a tracking detector to reach its ultimate position accuracy and momentum resolution. We developed a new alignment algorithm for the BESIII Main Drift Chamber using the Kalman Filter method. Two different types of data which are helix tracks and straight tracks are used to test this algorithm, and the results show that the design and implementation is successful.

  3. Swept shock/boundary-layer interactions: Scaling laws, flowfield structure, and experimental methods

    NASA Technical Reports Server (NTRS)

    Settles, Gary S.

    1993-01-01

    A general review is given of several decades of research on the scaling laws and flowfield structures of swept shock wave/turbulent boundary layer interactions. Attention is further restricted to the experimental study and physical understanding of the steady-state aspects of these flows. The interaction produced by a sharp, upright fin mounted on a flat plate is taken as an archetype. An overall framework of quasiconical symmetry describing such interactions is first developed. Boundary-layer separation, the interaction footprint, Mach number scaling, and Reynolds number scaling are then considered, followed by a discussion of the quasiconical similarity of interactions produced by geometrically-dissimilar shock generators. The detailed structure of these interaction flowfields is next reviewed, and is illustrated by both qualitative visualizations and quantitative flow images in the quasiconical framework. Finally, the experimental techniques used to investigate such flows are reviewed, with emphasis on modern non-intrusive optical flow diagnostics.

  4. A proposed experimental method for interpreting Doppler effect measurements and determining their precision

    NASA Technical Reports Server (NTRS)

    Klann, P. G.

    1973-01-01

    The principal problem in the measurement of the Doppler reactivity effect is separating it from the thermal reactivity effects of the expansion of the heated sample. It is shown in this proposal that the thermal effects of sample expansion can be experimentally determined by making additional measurements with porous samples having the same mass and/or volume as the primary sample. By combining these results with independent measurements of the linear temperature coefficient and the computed temperature dependence of the Doppler coefficient the magnitude of the Doppler coefficient may be extracted from the data. These addiational measurements are also useful to experimentally determine the precision of the reactivity oscillator technique used to measure the reactivity effects of the heated sample.

  5. Swept shock/boundary-layer interactions: Scaling laws, flowfield structure, and experimental methods

    NASA Technical Reports Server (NTRS)

    Settles, Gary S.

    1993-01-01

    A general review is given of several decades of research on the scaling laws and flowfield structures of swept shock wave/turbulent boundary layer interactions. Attention is further restricted to the experimental study and physical understanding of the steady-state aspects of these flows. The interaction produced by a sharp, upright fin mounted on a flat plate is taken as an archetype. An overall framework of quasiconical symmetry describing such interactions is first developed. Boundary-layer separation, the interaction footprint, Mach number scaling, and Reynolds number scaling are then considered, followed by a discussion of the quasiconical similarity of interactions produced by geometrically-dissimilar shock generators. The detailed structure of these interaction flowfields is next reviewed, and is illustrated by both qualitative visualizations and quantitative flow images in the quasiconical framework. Finally, the experimental techniques used to investigate such flows are reviewed, with emphasis on modern non-intrusive optical flow diagnostics.

  6. Applications of Advanced Experimental Methods to Visual Technology Research Simulator Studies: Supplemental Techniques.

    DTIC Science & Technology

    1981-01-01

    TECHNIQUES C. Wd. Simon Canyon Research Group, Inc. 741 Lakefilild Road, Suite B Westlakq*Village, California 91361 CI* FINAL REPORT MAY 1978 -MARCH 1980...AUGMENTATION b . USING YATES’ ALGORITHM WITH SCRFENING DESIGNS c. ANALYZING RESIDUALS 9 NAVTRAEQUIPCEN 78-C-0060-3 d. IDENTIFYING THE EXPERIMENTAL CONDITIONS...misinterpretations. Items a-iii, b , c, and f deal with topics related to the analysis of- such data. In some cases, proper data analysis may be substituted

  7. A new experimental method for determining liquid density and surface tension

    NASA Astrophysics Data System (ADS)

    Chou, Kjo-Chih; Hu, Jian-Hong

    1991-02-01

    A summary concerning the measurement of liquid density relying on the Archimedes principle has been presented, based on which a new effective method with a specially designed bob for determining liquid density has been suggested. The application of this method to ethyl alcohol solution and liquid glycerol, as well as a theoretical error analysis, shows that this new method is significant, because not only can it simplify the procedure of measurement but it can also offer more precise results. Besides, this method can further provide surface tension or contact angle simultaneously. It is expected that this new method will find its application in hightemperature melts.

  8. Human experimental pain models: A review of standardized methods in drug development

    PubMed Central

    Reddy, K. Sunil kumar; Naidu, M. U. R.; Rani, P. Usha; Rao, T. Ramesh Kumar

    2012-01-01

    Human experimental pain models are essential in understanding the pain mechanisms and appear to be ideally suited to test analgesic compounds. The challenge that confronts both the clinician and the scientist is to match specific treatments to different pain-generating mechanisms and hence reach a pain treatment tailored to each individual patient. Experimental pain models offer the possibility to explore the pain system under controlled settings. Standardized stimuli of different modalities (i.e., mechanical, thermal, electrical, or chemical) can be applied to the skin, muscles, and viscera for a differentiated and comprehensive assessment of various pain pathways and mechanisms. Using a multimodel-multistructure testing, the nociception arising from different body structures can be explored and modulation of specific biomarkers by new and existing analgesic drugs can be profiled. The value of human experimental pain models is to link animal and clinical pain studies, providing new possibilities for designing successful clinical trials. Spontaneous pain, the main compliant of the neuropathic patients, but currently there is no human model available that would mimic chronic pain. Therefore, current human pain models cannot replace patient studies for studying efficacy of analgesic compounds, although being helpful for proof-of-concept studies and dose finding. PMID:23626642

  9. An experimental test of CSR theory using a globally calibrated ordination method.

    PubMed

    Li, Yuanzhi; Shipley, Bill

    2017-01-01

    Can CSR theory, in conjunction with a recently proposed globally calibrated CSR ordination ("StrateFy"), using only three easily measured leaf traits (leaf area, specific leaf area and leaf dry matter content) predict the functional signature of herbaceous vegetation along experimentally manipulated gradients of soil fertility and disturbance? To determine this, we grew 37 herbaceous species in mixture for five years in 24 experimental mesocosms differing in factorial levels of soil resources (stress) and density-independent mortality (disturbance). We measured 16 different functional traits and then ordinated the resulting vegetation within the CSR triangle using StrateFy. We then calculated community-weighted mean (CWM) values of the competitor (CCWM), stress-tolerator (SCWM) and ruderal (RCWM) scores for each mesocosm. We found a significant increase in SCWM from low to high stress mesocosms, and an increase in RCWM from lowly to highly disturbed mesocosms. However, CCWM did not decline significantly as intensity of stress or disturbance increased, as predicted by CSR theory. This last result likely arose because our herbaceous species were relatively poor competitors in global comparisons and thus no strong competitors in our species pool were selectively favoured in low stress and low disturbed mesocosms. Variation in the 13 other traits, not used by StrateFy, largely argeed with the predictions of CSR theory. StrateFy worked surprisingly well in our experimental study except for the C-dimension. Despite loss of some precision, it has great potential applicability in future studies due to its simplicity and generality.

  10. A method of experimental determination of the profiles of temperature and composition of a high-temperature gas stream

    NASA Astrophysics Data System (ADS)

    Godlevskii, V. E.; Gradov, V. N.; Levin, V. Ia.; Nigodiuk, V. E.; Shustov, S. A.

    1980-11-01

    A simple method for determining the characteristics of a high-temperature gas flow is described; the method is based on measurements of mass removal from and size reduction of a polymethyl methacrylate plate placed in the flow. A system of equations describing the destruction of the plate in a high-temperature subsonic flow is obtained and applied to the examination of the temperature and composition of combustion products containing C, N, H, and O. An experimental confirmation of the proposed method is presented.

  11. Experimental study on seismic responses of piping systems with friction. Part 2: Simplified analysis method on the effect of friction

    SciTech Connect

    Kobayashi, H.; Yokoi, R.; Chiba, T.; Suzuki, K.; Shimizu, N.; Minowa, C.

    1995-08-01

    Friction between pipe and support structure is generally known to reduce seismic response of the piping systems. Vibration tests using large-scale piping model with friction support were carried out to evaluate the reduction effect. The piping response was mainly governed by the first modal deformation. The simplified analysis method based on linear response spectrum analysis was developed and confirmed to be applicable. In this method, the reduction effect by friction is treated as equivalent viscous damping ratio. This paper deals with the analysis method, and the comparison between the experimental results and analytical ones.

  12. Comparison of the Experimental Performance of Ferroelectric CPW Circuits with Method of Moment Simulations and Conformal Mapping

    NASA Technical Reports Server (NTRS)

    VanKeuls, Fred W.; Chevalier, Chris T.; Miranda, Felix A.; Carlson, C. M.; Rivkin, T. V.; Parilla, P. A.; Perkins, J. D.; Ginley, D. S.

    2001-01-01

    Experimental measurements of coplanar waveguide (CPW) circuits atop thin films of ferroelectric Ba(x)Sr(1-x)TiO3 (BST) were made as a function bias from 0 to 200 V and frequency from 0.045 to 20 GHz. The resulting phase shifts are compared with method of moments electromagnetic simulations and a conformal mapping analysis to determine the dielectric constant of the BST films. Based on the correlation between the experimental and the modeled data, an analysis of the extent to which the electromagnetic simulators provide reliable values for the dielectric constant of the ferroelectric in these structures has been performed. In addition, to determine how well the modeled data compare with experimental data, the dielectric constant values were also compared to low frequency measurements of interdigitated capacitor circuits on the same films. Results of these comparisons will be presented.

  13. Estimating heritabilities and genetic correlations with marker-based methods: an experimental test in Mimulus guttatus.

    PubMed

    van Kleunen, M; Ritland, K

    2005-01-01

    The calculation of heritabilities and genetic correlations, which are necessary for predicting evolutionary responses, requires knowledge about the relatedness between individuals. This information is often not directly available, especially not for natural populations, but can be inferred by using molecular markers such as allozymes. Several methods based on inferred relatedness from marker data have been developed to estimate heritabilities and genetic correlations in natural populations. Most methods use maximum-likelihood procedures to assign pairs or groups of individuals to predefined discrete relatedness classes (e.g., half sibs and unrelated individuals). The Ritland method, on the other hand, uses method of moments estimators to estimate pairwise relatedness among individuals as continuous values. We tested both the Ritland method and a maximum-likelihood method by applying them to a greenhouse population consisting of seed families of the herb Mimulus guttatus and comparing the results to the ones from a frequently used standard method based on half-sib families. Estimates of genetic correlations were far from accurate, especially when we used the Ritland method. However, this study shows that even with a few variable allozyme loci, it is possible to get qualitatively good indications about the presence of heritable genetic variation from marker-based methods, even though both methods underestimated it.

  14. Reducing the effects of acoustic heterogeneity with an iterative reconstruction method from experimental data in microwave induced thermoacoustic tomography.

    PubMed

    Wang, Jinguo; Zhao, Zhiqin; Song, Jian; Chen, Guoping; Nie, Zaiping; Liu, Qing-Huo

    2015-05-01

    An iterative reconstruction method has been previously reported by the authors of this paper. However, the iterative reconstruction method was demonstrated by solely using the numerical simulations. It is essential to apply the iterative reconstruction method to practice conditions. The objective of this work is to validate the capability of the iterative reconstruction method for reducing the effects of acoustic heterogeneity with the experimental data in microwave induced thermoacoustic tomography. Most existing reconstruction methods need to combine the ultrasonic measurement technology to quantitatively measure the velocity distribution of heterogeneity, which increases the system complexity. Different to existing reconstruction methods, the iterative reconstruction method combines time reversal mirror technique, fast marching method, and simultaneous algebraic reconstruction technique to iteratively estimate the velocity distribution of heterogeneous tissue by solely using the measured data. Then, the estimated velocity distribution is used subsequently to reconstruct the highly accurate image of microwave absorption distribution. Experiments that a target placed in an acoustic heterogeneous environment are performed to validate the iterative reconstruction method. By using the estimated velocity distribution, the target in an acoustic heterogeneous environment can be reconstructed with better shape and higher image contrast than targets that are reconstructed with a homogeneous velocity distribution. The distortions caused by the acoustic heterogeneity can be efficiently corrected by utilizing the velocity distribution estimated by the iterative reconstruction method. The advantage of the iterative reconstruction method over the existing correction methods is that it is successful in improving the quality of the image of microwave absorption distribution without increasing the system complexity.

  15. Ultrasound and electric pulses for transdermal drug delivery enhancement: Ex vivo assessment of methods with in vivo oriented experimental protocols.

    PubMed

    Zorec, Barbara; Jelenc, Jure; Miklavčič, Damijan; Pavšelj, Nataša

    2015-07-25

    In our present study we focus on two physical enhancement methods for transdermal drug delivery: ultrasound and electric pulses either alone or in combination. Great emphasis has been given on the design of the experimental system and protocols, so the results and the conclusions drawn from them would have greater relevance for in vivo use and later translation into clinical practice. Our results show a statistically significant enhancement of calcein delivery (after one hour of passive diffusion following treatment) already after 5 minutes of ultrasound application, or only 6 × 100 short high voltage electrical pulses. We also experimented with combinations of the two enhancement methods hoping for synergistic effects, however, the results showed no evident drastic improvement over single method. Looking closer at physics of both methods, this absence of synergy in our in vivo oriented experimental setting is not surprising. The mechanism of action of both methods is the creation of aqueous pathways in the stratum corneum leading to increased skin permeability. However, when used in combination (regardless of the order of methods), the second method was unsuccessful in adding many new aqueous pathways in the stratum corneum, as it acted preferentially near the sites of the existing ones.

  16. Experimental Null Method to Guide the Development of Technical Procedures and to Control False-Positive Discovery in Quantitative Proteomics.

    PubMed

    Shen, Xiaomeng; Hu, Qiang; Li, Jun; Wang, Jianmin; Qu, Jun

    2015-10-02

    Comprehensive and accurate evaluation of data quality and false-positive biomarker discovery is critical to direct the method development/optimization for quantitative proteomics, which nonetheless remains challenging largely due to the high complexity and unique features of proteomic data. Here we describe an experimental null (EN) method to address this need. Because the method experimentally measures the null distribution (either technical or biological replicates) using the same proteomic samples, the same procedures and the same batch as the case-vs-contol experiment, it correctly reflects the collective effects of technical variability (e.g., variation/bias in sample preparation, LC-MS analysis, and data processing) and project-specific features (e.g., characteristics of the proteome and biological variation) on the performances of quantitative analysis. To show a proof of concept, we employed the EN method to assess the quantitative accuracy and precision and the ability to quantify subtle ratio changes between groups using different experimental and data-processing approaches and in various cellular and tissue proteomes. It was found that choices of quantitative features, sample size, experimental design, data-processing strategies, and quality of chromatographic separation can profoundly affect quantitative precision and accuracy of label-free quantification. The EN method was also demonstrated as a practical tool to determine the optimal experimental parameters and rational ratio cutoff for reliable protein quantification in specific proteomic experiments, for example, to identify the necessary number of technical/biological replicates per group that affords sufficient power for discovery. Furthermore, we assessed the ability of EN method to estimate levels of false-positives in the discovery of altered proteins, using two concocted sample sets mimicking proteomic profiling using technical and biological replicates, respectively, where the true

  17. An experimental method for measuring droplet impingement efficiency on two- and three-dimensional bodies

    NASA Technical Reports Server (NTRS)

    Papadakis, M.; Zumwalt, G. W.; Kim, J. J.; Elangovan, R.; Freund, G. A., Jr.

    1986-01-01

    An efficient and accurate method is described for extracting water droplet impingement efficiency data from dye impregnated blotter paper samples obtained by employing a dye-tracer technique in wind tunnel spray tests. The method is based on laser reflectance spectroscopy. A brief description of the test method, instrumentation, and data reduction system is also presented. Preliminary test results and analyses are included for a cylinder and a 65(2)015 airfoil.

  18. NOVEL METHODS FOR EXPERIMENTAL CHARACTERIZATION OF 3D SUPERCONDUCTING LINAC BEAM DYNAMICS

    SciTech Connect

    Shishlo, Andrei P

    2013-01-01

    This paper describes an approach to measure initial Twiss parameters in transverse and longitudinal directions at the entrance of a linac with independent short accelerating cavities. For the transverse plane the usual technique of transverse profiles is used, and for the longitudinal direction a recently developed non-intercepting method is applied. The new method is based on a beam position monitor amplitudes analysis. The applicability of the methods are discussed and demonstrated on an example of the Spallation Neutron Source superconducting linac.

  19. An experimental method for measuring droplet impingement efficiency on two- and three-dimensional bodies

    NASA Technical Reports Server (NTRS)

    Papadakis, M.; Zumwalt, G. W.; Kim, J. J.; Elangovan, R.; Freund, G. A., Jr.

    1986-01-01

    An efficient and accurate method is described for extracting water droplet impingement efficiency data from dye impregnated blotter paper samples obtained by employing a dye-tracer technique in wind tunnel spray tests. The method is based on laser reflectance spectroscopy. A brief description of the test method, instrumentation, and data reduction system is also presented. Preliminary test results and analyses are included for a cylinder and a 65(2)015 airfoil.

  20. Application of the optical method in experimental cardiology: action potential and intracellular calcium concentration measurement.

    PubMed

    Ronzhina, M; Cmiel, V; Janoušek, O; Kolářová, J; Nováková, M; Babula, P; Provazník, I

    2013-01-01

    It has been shown that, in addition to conventional contact electrode techniques, optical methods using fluorescent dyes can be successfully used for cardiac signal measurement. In this review, the physical and technical fundamentals of the method are described, as well as the properties of the most common systems for measuring action potentials and intracellular calcium concentration. Special attention is paid to summarizing limitations and trends in developing this method.

  1. Temperature mapping in bread dough using SE and GE two-point MRI methods: experimental and theoretical estimation of uncertainty.

    PubMed

    Lucas, Tiphaine; Musse, Maja; Bornert, Mélanie; Davenel, Armel; Quellec, Stéphane

    2012-04-01

    Two-dimensional (2D)-SE, 2D-GE and tri-dimensional (3D)-GE two-point T(1)-weighted MRI methods were evaluated in this study in order to maximize the accuracy of temperature mapping of bread dough during thermal processing. Uncertainties were propagated throughout each protocol of measurement, and comparisons demonstrated that all the methods with comparable acquisition times minimized the temperature uncertainty to similar extent. The experimental uncertainties obtained with low-field MRI were also compared to the theoretical estimations. Some discrepancies were reported between experimental and theoretical values of uncertainties of temperature; however, experimental and theoretical trends with varying parameters agreed to a large extent for both SE and GE methods. The 2D-SE method was chosen for further applications on prefermented dough because of its lower sensitivity to susceptibility differences in porous media. It was applied for temperature mapping in prefermented dough during chilling prior to freezing and compared locally to optical fiber measurements. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. An innovative method for coordinate measuring machine one-dimensional self-calibration with simplified experimental process.

    PubMed

    Fang, Cheng; Butler, David Lee

    2013-05-01

    In this paper, an innovative method for CMM (Coordinate Measuring Machine) self-calibration is proposed. In contrast to conventional CMM calibration that relies heavily on a high precision reference standard such as a laser interferometer, the proposed calibration method is based on a low-cost artefact which is fabricated with commercially available precision ball bearings. By optimizing the mathematical model and rearranging the data sampling positions, the experimental process and data analysis can be simplified. In mathematical expression, the samples can be minimized by eliminating the redundant equations among those configured by the experimental data array. The section lengths of the artefact are measured at arranged positions, with which an equation set can be configured to determine the measurement errors at the corresponding positions. With the proposed method, the equation set is short of one equation, which can be supplemented by either measuring the total length of the artefact with a higher-precision CMM or calibrating the single point error at the extreme position with a laser interferometer. In this paper, the latter is selected. With spline interpolation, the error compensation curve can be determined. To verify the proposed method, a simple calibration system was set up on a commercial CMM. Experimental results showed that with the error compensation curve uncertainty of the measurement can be reduced to 50%.

  3. Experimental comparison of methods for estimation of the observed velocity of the vehicle in video stream

    NASA Astrophysics Data System (ADS)

    Konovalenko, Ivan; Kuznetsova, Elena

    2015-02-01

    In this paper, we consider the problem of object's velocity estimation via video stream by comparing three new methods of velocity estimation named as vertical edge algorithm, modified Lucas-Kanade method, and feature points algorithm. As an applied example the task of automatic evaluation of vehicles' velocity via video stream on toll roads is chosen. We took some videos from cameras mounted on the toll roads and marked them out to determine true velocity. Comparison is carried out of performance in the correct velocity detection of the proposed methods with each other. The relevance of this paper is practical implementation of these methods overcoming all the difficulties of realization.

  4. DETECTORS AND EXPERIMENTAL METHODS: Study of BESIII MUC offline software with cosmic-ray data

    NASA Astrophysics Data System (ADS)

    Liang, Yu-Tie; Mao, Ya-Jun; You, Zheng-Yun; Li, Wei-Dong; Bian, Jian-Ming; Cao, Guo-Fu; Cao, Xue-Xiang; Chen, Shen-Jian; Deng, Zi-Yan; Fu, Cheng-Dong; Gao, Yuan-Ning; Han, Lei; Han, Shao-Qing; He, Kang-Lin; He, Miao; Hu, Ji-Feng; Hu, Xiao-Wei; Huang, Bin; Huang, Xing-Tao; Jia, Lu-Kui; Ji, Xiao-Bin; Li, Hai-Bo; Liu, Bei-Jiang; Liu, Chun-Xiu; Liu, Huai-Min; Liu, Ying; Liu, Yong; Luo, Tao; Lu, Qi-Wen; Ma, Qiu-Mei; Ma, Xiang; Mao, Ze-Pu; Mo, Xiao-Hu; Ning, Fei-Peng; Ping, Rong-Gang; Qiu, Jin-Fa; Song, Wen-Bo; Sun, Sheng-Sen; Sun, Xiao-Dong; Sun, Yong-Zhao; Tian, Hao-Lai; Wang, Ji-Ke; Wang, Liang-Liang; Wen, Shuo-Pin; Wu, Ling-Hui; Wu, Zhi; Xie, Yu-Guang; Xu, Min; Yan, Jie; Yan, Liang; Yao, Jian; Yuan, Chang-Zheng; Yuan, Ye; Zhang, Chang-Chun; Zhang, Jian-Yong; Zhang, Lei; Zhang, Xue-Yao; Zhang, Yao; Zheng, Yang-Heng; Zhu, Yong-Sheng; Zou, Jia-Heng

    2009-07-01

    Cosmic-ray data of 90 M events have been collected and used for calibration, alignment as well as detector tuning. A special tracking algorithm for the BESIII muon counter is developed and verified with Monte-Carlo simulation and then further confirmed with the cosmic-ray data. The obtained strip resolutions are in good agreement with the design values. A new alignment approach for the BESIII muon counter is confirmed with the cosmic-ray data and proposed to be used in future analysis of experimental data.

  5. Estimation of transverse spin penetration length using second-harmonic measurement: Proposal of an experimental method

    NASA Astrophysics Data System (ADS)

    Baláž, Pavel; Zwierzycki, Maciej; Ansermet, Jean-Philippe; Barnaś, Józef

    2016-10-01

    A theoretical description of spin current injection from a nonmagnetic layer into a magnetic one is presented, with the main emphasis on the description and determination of the penetration depth of spin current component transverse to the magnetization. This penetration depth also determines the depth of spin transfer torque generation. Physically, the spin current may be driven by an external electric field or by a temperature gradient. To determine the penetration depth we used ab initio calculations of channel and mixing conductances as well as of mixing transmission. The results are then used to determine the second harmonic voltage response, which in turn can be used to determine the penetration depth experimentally.

  6. DETECTORS AND EXPERIMENTAL METHODS: ELDRS and dose-rate dependence of vertical NPN transistor

    NASA Astrophysics Data System (ADS)

    Zheng, Yu-Zhan; Lu, Wu; Ren, Di-Yuan; Wang, Gai-Li; Yu, Xue-Feng; Guo, Qi

    2009-01-01

    The enhanced low-dose-rate sensitivity (ELDRS) and dose-rate dependence of vertical NPN transistors are investigated in this article. The results show that the vertical NPN transistors exhibit more degradation at low dose rate, and that this degradation is attributed to the increase on base current. The oxide trapped positive charge near the SiO2-Si interface and interface traps at the interface can contribute to the increase on base current and the two-stage hydrogen mechanism associated with space charge effect can well explain the experimental results.

  7. Experimental examination of similarity measures and preprocessing methods used for image registration

    NASA Technical Reports Server (NTRS)

    Svedlow, M.; Mcgillem, C. D.; Anuta, P. E.

    1976-01-01

    The criterion used to measure the similarity between images and thus find the position where the images are registered is examined. The three similarity measures considered are the correlation coefficient, the sum of the absolute differences, and the correlation function. Three basic types of preprocessing are then discussed: taking the magnitude of the gradient of the images, thresholding the images at their medians, and thresholding the magnitude of the gradient of the images at an arbitrary level to be determined experimentally. These multitemporal registration techniques are applied to remote imagery of agricultural areas.

  8. Application of activation methods on the Dubna experimental transmutation set-ups.

    PubMed

    Stoulos, S; Fragopoulou, M; Adloff, J C; Debeauvais, M; Brandt, R; Westmeier, W; Krivopustov, M; Sosnin, A; Papastefanou, C; Zamani, M; Manolopoulou, M

    2003-02-01

    High spallation neutron fluxes were produced by irradiating massive heavy targets with proton beams in the GeV range. The experiments were performed at the Dubna High Energy Laboratory using the nuclotron accelerator. Two different experimental set-ups were used to produce neutron spectra convenient for transmutation of radioactive waste by (n,x) reactions. By a theoretical analysis neutron spectra can be reproduced from activation measurements. Thermal-epithermal and fast-super-fast neutron fluxes were estimated using the 197Au, 238U (n,gamma) and (n,2n) reactions, respectively. Depleted uranium transmutation rates were also studied in both experiments.

  9. Design of a laboratory method for rapid evaluation of experimental flocculants

    USDA-ARS?s Scientific Manuscript database

    Reports of novel organic polymeric flocculants have become commonplace. The method used to test the effectiveness of these flocculants is most often the flocculation of a kaolin suspension in a jar test. The widely varying versions of this method that appear in the literature suffer from a range o...

  10. Analyzing Empirical Evaluations of Non-Experimental Methods in Field Settings

    ERIC Educational Resources Information Center

    Steiner, Peter M.; Wong, Vivian

    2016-01-01

    Despite recent emphasis on the use of randomized control trials (RCTs) for evaluating education interventions, in most areas of education research, observational methods remain the dominant approach for assessing program effects. Over the last three decades, the within-study comparison (WSC) design has emerged as a method for evaluating the…

  11. Comparison of Three Methods for Teaching and Evaluating Writing: A Quasi-Experimental Study

    ERIC Educational Resources Information Center

    Plutsky, Susan; Wilson, Barbara A.

    2004-01-01

    This study was undertaken to determine whether significant differences exist in the performance of students based on three methods for teaching and evaluating writing: faculty review, group review, and Calibrated Peer Review (CPR), an Internet software program designed to teach writing. Classes were randomly assigned a method; 148 students were…

  12. Theoretical and experimental comparative analysis of beamforming methods for loudspeaker arrays under given performance constraints

    NASA Astrophysics Data System (ADS)

    Olivieri, Ferdinando; Fazi, Filippo Maria; Nelson, Philip A.; Shin, Mincheol; Fontana, Simone; Yue, Lang

    2016-07-01

    Methods for beamforming are available that provide the signals used to drive an array of sources for the implementation of systems for the so-called personal audio. In this work, performance of the delay-and-sum (DAS) method and of three widely used methods for optimal beamforming are compared by means of computer simulations and experiments in an anechoic environment using a linear array of sources with given constraints on quality of the reproduced field at the listener's position and limit to input energy to the array. Using the DAS method as a benchmark for performance, the frequency domain responses of the loudspeaker filters can be characterized in three regions. In the first region, at low frequencies, input signals designed with the optimal methods are identical and provide higher directivity performance than that of the DAS. In the second region, performance of the optimal methods are similar to the DAS method. The third region starts above the limit due to spatial aliasing. A method is presented to estimate the boundaries of these regions.

  13. A Novel Method to Compute Breathing Volumes via Motion Capture Systems: Design and Experimental Trials.

    PubMed

    Massaroni, Carlo; Cassetta, Eugenio; Silvestri, Sergio

    2017-03-24

    Respiratory assessment can be carried out by using motion capture systems. A geometrical model is mandatory in order to compute the breathing volume as a function of time from the markers trajectories. This study describes a novel model to compute volume changes and calculate respiratory parameters by using a motion capture system. The novel method, i.e. prism-based method, computes the volume enclosed within the chest by defining 82 prisms from the 89 markers attached to the subject chest. Volumes computed with this method are compared to spirometry volumes and to volumes computed by a conventional method based on the tetrahedrons decomposition of the chest wall and integrated in a commercial motion capture system. Eight healthy volunteers were enrolled and 30 seconds quiet breathing collected from each of them. Results show a better agreement between volumes computed by the prism-based method and the spirometry (discrepancy of 2.23%, R(2)=0.94) compared to the agreement between volumes computed by the conventional method and the spirometry (discrepancy of 3.56%, R(2)=0.92). The proposed method also showed better performances in the calculation of respiratory parameters. Our findings open up prospects for the further use of the new method in the breathing assessment via motion capture systems.

  14. Comparison of Three Methods for Teaching and Evaluating Writing: A Quasi-Experimental Study

    ERIC Educational Resources Information Center

    Plutsky, Susan; Wilson, Barbara A.

    2004-01-01

    This study was undertaken to determine whether significant differences exist in the performance of students based on three methods for teaching and evaluating writing: faculty review, group review, and Calibrated Peer Review (CPR), an Internet software program designed to teach writing. Classes were randomly assigned a method; 148 students were…

  15. Shear Lag in Box Beams Methods of Analysis and Experimental Investigations

    NASA Technical Reports Server (NTRS)

    Kuhn, Paul; Chiarito, Patrick T

    1942-01-01

    The bending stresses in the covers of box beams or wide-flange beams differ appreciably from the stresses predicted by the ordinary bending theory on account of shear deformation of the flanges. The problem of predicting these differences has become known as the shear-lag problem. The first part of this paper deals with methods of shear-lag analysis suitable for practical use. The second part of the paper describes strain-gage tests made by the NACA to verify the theory. Three tests published by other investigators are also analyzed by the proposed method. The third part of the paper gives numerical examples illustrating the methods of analysis. An appendix gives comparisons with other methods, particularly with the method of Ebner and Koller.

  16. Characterisation of blast loading in complex, confined geometries using quarter symmetry experimental methods

    NASA Astrophysics Data System (ADS)

    Anthistle, T.; Fletcher, D. I.; Tyas, A.

    2016-11-01

    Explosions in confined spaces lead to complicated patterns of shock wave reflection and interactions which are best investigated by use of experimental tests or numerical simulations. This paper describes the design and outcome of a series of experiments using a test cell to measure the pressures experienced when structures were placed inside to alter the propagation of shock waves, utilising quarter symmetry to reduce the size of the required test cell and charge. An 80 g charge of PE4 (a conventional RDX-based plastic explosive) was placed at half height in one corner of the test cell, which represents the centre of a rectangular enclosure when symmetry is taken into consideration. Steel cylinders and rectangular baffles were placed within the test cell at various locations. Good reproducibility was found between repeated tests in three different arrangements, in terms of both the recorded pressure data and the calculated cumulative impulse. The presence of baffles within the test cell made a small difference to the pressures and cumulative impulse experienced compared to tests with no baffles present; however, the number and spacing of baffles was seen to make minimal difference to the experienced pressures and no noticeable difference to the cumulative impulse history. The paper presents useful experimental data that may be used for three-dimensional code validation.

  17. Robotic Lunar Ecopoiesis Test Bed: Bringing the Experimental Method to Terraforming

    NASA Astrophysics Data System (ADS)

    Boston, Penelope J.; Todd, Paul; McMillen, Keli R.

    2004-02-01

    The notion of ecologically terraforming another planet (aka ecopoiesis) has been discussed by a number of scholars. Some theoretical treatments of various aspects of ecopoiesis have appeared in the literature. However, experimental terraforming studies have been rare to non-existent. This is not surprising because of the planetary scale and long durations typically discussed. We describe a concept to perform basic ecopoietic experiments in a test facility constructed on the lunar surface. Such a facility can provide long-term observation of organisms and their ecological, physiological, and evolutionary interactions in a low gravity environment. Salient features of other extraterrestrial environments (e.g. the 0.38g Mars gravity) can be simulated more easily in the lunar milieu than on Earth while providing much greater access for experimenters than ecopoiesis experiments on Mars itself. Besides application of these proposed studies to possible future terraforming efforts, basic evolutionary and ecological processes could be studied under extreme selection pressures including fractional gravity, high radiation, and with a variety of atmospheres, soils, and other parameters. Novel, genetically engineered and selectively bred organisms could be tested in such a facility without concern for accidental release into Earth's environment.

  18. New methods for monitoring dynamic airway tissue oxygenation and perfusion in experimental and clinical transplantation.

    PubMed

    Khan, Mohammad A; Dhillon, Gundeep; Jiang, Xinguo; Lin, Yu-Chun; Nicolls, Mark R

    2012-11-15

    A dual circulation, supplied by bronchial and pulmonary artery-derived vessels, normally perfuses the airways from the trachea to the terminal bronchioles. This vascular system has been highly conserved through mammalian evolution and is disrupted at the time of lung transplantation. In most transplant centers, this circulation is not restored. The Papworth Hospital Autopsy study has revealed that an additional attrition of periairway vessels is associated with the development of chronic rejection, otherwise known as the bronchiolitis obliterans syndrome (BOS). Experimental studies subsequently demonstrated that airway vessels are subject to alloimmune injury and that the loss of a functional microvascular system identifies allografts that cannot be rescued with immunosuppressive therapy. Therefore, surgical and medical strategies, which preserve the functionality of the existent vasculature in lung transplant patients, may conceivably limit the incidence of BOS. Given these unique anatomic and physiological considerations, there is an emerging rationale to better understand the perfusion and oxygenation status of airways in transplanted lungs. This article describes novel methodologies, some newly developed by our group, for assessing airway tissue oxygenation and perfusion in experimental and clinical transplantation.

  19. A comparative experimental evaluation of uncertainty estimation methods for two-component PIV

    NASA Astrophysics Data System (ADS)

    Boomsma, Aaron; Bhattacharya, Sayantan; Troolin, Dan; Pothos, Stamatios; Vlachos, Pavlos

    2016-09-01

    Uncertainty quantification in planar particle image velocimetry (PIV) measurement is critical for proper assessment of the quality and significance of reported results. New uncertainty estimation methods have been recently introduced generating interest about their applicability and utility. The present study compares and contrasts current methods, across two separate experiments and three software packages in order to provide a diversified assessment of the methods. We evaluated the performance of four uncertainty estimation methods, primary peak ratio (PPR), mutual information (MI), image matching (IM) and correlation statistics (CS). The PPR method was implemented and tested in two processing codes, using in-house open source PIV processing software (PRANA, Purdue University) and Insight4G (TSI, Inc.). The MI method was evaluated in PRANA, as was the IM method. The CS method was evaluated using DaVis (LaVision, GmbH). Utilizing two PIV systems for high and low-resolution measurements and a laser doppler velocimetry (LDV) system, data were acquired in a total of three cases: a jet flow and a cylinder in cross flow at two Reynolds numbers. LDV measurements were used to establish a point validation against which the high-resolution PIV measurements were validated. Subsequently, the high-resolution PIV measurements were used as a reference against which the low-resolution PIV data were assessed for error and uncertainty. We compared error and uncertainty distributions, spatially varying RMS error and RMS uncertainty, and standard uncertainty coverages. We observed that qualitatively, each method responded to spatially varying error (i.e. higher error regions resulted in higher uncertainty predictions in that region). However, the PPR and MI methods demonstrated reduced uncertainty dynamic range response. In contrast, the IM and CS methods showed better response, but under-predicted the uncertainty ranges. The standard coverages (68% confidence interval) ranged from

  20. DETECTORS AND EXPERIMENTAL METHODS Study of low momentum track reconstruction for the BESIII main drift chamber

    NASA Astrophysics Data System (ADS)

    Jia, Lu-Kui; Mao, Ze-Pu; Li, Wei-Dong; Cao, Guo-Fu; Cao, Xue-Xiang; Deng, Zi-Yan; He, Kang-Lin; Liu, Chun-Yan; Liu, Huai-Min; Liu, Qiu-Guang; Ma, Qiu-Mei; Ma, Xiang; Qiu, Jin-Fa; Tian, Hao-Lai; Wang, Ji-Ke; Wu, Ling-Hui; Yuan, Ye; Zang, Shi-Lei; Zhang, Chang-Chun; Zhang, Lei; Zhang, Yao; Zhu, Kai; Zou, Jia-Heng

    2010-12-01

    In order to overcome the difficulty brought by the circling charged tracks with transverse momentum less than 120 MeV in the BESIII Main Drift Chamber (MDC), a specialized method called TCurlFinder was developed. This tracking method focuses on the charged track reconstruction under 120 MeV and possesses a special mechanism to reject background noise hits. The performance of the package has been carefully checked and tuned by both Monte Carlo data and real data. The study shows that this tracking method could obviously enhance the reconstruction efficiency in the low transverse momentum region, providing physics analysis with more and reliable data.

  1. Experimental and analytical methods for the determination of connected-pipe ramjet and ducted rocket internal performance

    NASA Astrophysics Data System (ADS)

    1994-07-01

    Connected-pipe, subsonic combustion ramjet and ducted rocket performance determination procedures used by the NATO countries have been reviewed and evaluated. A working document has been produced which provides recommended methods for reporting test results and delineates the parameters that are required to be measured. Explanations and detailed numerical examples are presented covering the determination of both theoretical and experimental performances, the use of air heaters and uncertainty and error analysis.

  2. Experimental methods in cryogenic spectroscopy: Stark effect measurements in substituted myoglobin

    NASA Astrophysics Data System (ADS)

    Moran, Bradley M.

    Dawning from well-defined tertiary structure, the active regions of enzymatic proteins exist as specifically tailored electrostatic microenvironments capable of facilitating chemical interaction. The specific influence these charge distributions have on ligand binding dynamics, and their impact on specificity, reactivity, and biological functionality, have yet to be fully understood. A quantitative determination of these intrinsic fields would offer insight towards the mechanistic aspects of protein functionality. This work seeks to investigate the internal molecular electric fields that are present at the oxygen binding site of myoglobin. Experiments are performed at 1 K on samples located within a glassy matrix, using the high-resolution technique spectral hole-burning. The internal electric field distributions can be explored by implementing a unique mathematical treatment for analyzing the effect that externally applied electric fields have on the spectral hole profiles. Precise control of the light field, the temperature, and the externally applied electric field at the site of the sample is crucial. Experimentally, the functionality of custom cryogenic temperature confocal scanning microscope was extended to allow for collection of imaging and spectral data with the ability to modulate the polarization of the light at the sample. Operation of the instrumentation was integrated into a platform allowing for seamless execution of input commands with high temporal inter-instrument resolution for collection of data streams. For the regulated control and cycling of the sample temperature. the thermal characteristics of the research Dewar were theoretically modeled to systematically predict heat flows throughout the system. A high voltage feedthrough for delivering voltages of up to 5000 V to the sample as positioned within the Dewar was developed. The burning of spectral holes with this particular experimental setup is highly repeatable. The quantum mechanical

  3. Experimental Reading with Invented Spelling (ERIS): A Preschool and Kindergarten Method.

    ERIC Educational Resources Information Center

    Richgels, Donald J.

    1987-01-01

    Describes a program that associates phonics instruction with children's earliest reading and writing, using the ERIS method to teach sound/letter correspondences and to provide opportunities for writing and reading. (NKA)

  4. Experimental method for the determination of adsorption-induced changes of pressure and surface stress in nanopores

    NASA Astrophysics Data System (ADS)

    Schappert, Klaus; Pelster, Rolf

    2017-02-01

    The change of surface stress is an important quantity characterising the behaviour of nanoporous systems, however, it is difficult to assess experimentally. In this letter we develop and demonstrate an experimental method for the determination of adsorption-induced changes of the surface stress in nanoporous materials. With the aid of ultrasonic measurements we determine the dependence of the adsorbate’s longitudinal modulus {β\\text{Ar,\\text{ads}}} on the adsorption-induced normal pressure, Δ {{p}\\text{S}} , which is exerted by the adsorbate on the porous matrix. From this dependence we deduce the normal pressure at saturation, Δ p\\text{S}\\text{sat} , and thereby changes of the surface stress {{≤ft(Δ f\\right)}\\text{sat}} at the interface between the solid matrix and the liquid adsorbate. For the model system of argon in nanoporous glass (pore radius {{r}\\text{P}}=3.8 nm) the ultrasonic method reveals a value for Δ p\\text{S}\\text{sat} that is in very good agreement with the theoretical value known for the argon-silica interface. The disclosure of this experimental method and its application on other systems will enable a better understanding of the behaviour of adsorbates in nanoporous materials.

  5. Experimental method for the determination of adsorption-induced changes of pressure and surface stress in nanopores.

    PubMed

    Schappert, Klaus; Pelster, Rolf

    2017-02-15

    The change of surface stress is an important quantity characterising the behaviour of nanoporous systems, however, it is difficult to assess experimentally. In this letter we develop and demonstrate an experimental method for the determination of adsorption-induced changes of the surface stress in nanoporous materials. With the aid of ultrasonic measurements we determine the dependence of the adsorbate's longitudinal modulus [Formula: see text] on the adsorption-induced normal pressure, [Formula: see text], which is exerted by the adsorbate on the porous matrix. From this dependence we deduce the normal pressure at saturation, [Formula: see text], and thereby changes of the surface stress [Formula: see text] at the interface between the solid matrix and the liquid adsorbate. For the model system of argon in nanoporous glass (pore radius [Formula: see text] nm) the ultrasonic method reveals a value for [Formula: see text] that is in very good agreement with the theoretical value known for the argon-silica interface. The disclosure of this experimental method and its application on other systems will enable a better understanding of the behaviour of adsorbates in nanoporous materials.

  6. Using highly efficient nonlinear experimental design methods for optimization of Lactococcus lactis fermentation in chemically defined media.

    PubMed

    Zhang, Guiying; Block, David E

    2009-01-01

    Optimization of fermentation media and processes is a difficult task due to the potential for high dimensionality and nonlinearity. Here we develop and evaluate variations on two novel and highly efficient methods for experimental fermentation optimization. The first approach is based on using a truncated genetic algorithm with a developing neural network model to choose the best experiments to run. The second approach uses information theory, along with Bayesian regularized neural network models, for experiment selection. To evaluate these methods experimentally, we used them to develop a new chemically defined medium for Lactococcus lactis IL1403, along with an optimal temperature and initial pH, to achieve maximum cell growth. The media consisted of 19 defined components or groups of components. The optimization results show that the maximum cell growth from the optimal process of each novel method is generally comparable to or higher than that achieved using a traditional statistical experimental design method, but these optima are reached in about half of the experiments (73-94 vs. 161, depending on the variants of methods). The optimal chemically defined media developed in this work are rich media that can support high cell density growth 3.5-4 times higher than the best reported synthetic medium and 72% higher than a commonly used complex medium (M17) at optimization scale. The best chemically defined medium found using the method was evaluated and compared with other defined or complex media at flask- and fermentor-scales. (c) 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009.

  7. An Experimental Study of DLV Method in Damage Detection of Frame Structures

    NASA Astrophysics Data System (ADS)

    Wang, Yen-Po; Chen, Yi-Hsuan; Lee, Chien-Liang

    2010-05-01

    A structural damage detection method integrating the damage locating vector (DLV) method and ARX model for system identification of frame structures from seismic acceleration responses has been explored in this paper. The concept of the DLV method is to identify the members with zero stress under some specific loading patterns derived from the changes in flexibility matrix of the structure before and after the damage state. Success of the DLV method requires clear identification of the flexibility matrix for at least the first few dominant modes. In this study, a five-storey steel frame with diagonal bracings is considered as the objective building. The damage condition of the structure is simulated by partially removing some of the diagonals. With the flexibility matrices of both the intact and damaged structure identified from seismic structural responses via shaking table tests, results indicate that the damaged locations can be successfully identified by the DLV method if sufficient modes of vibration are taken into account in the realization of the flexibility matrices. The feasibility of using DLV method for damage detection of frame structures using seismic response data is confirmed.

  8. Experimental and theoretical studies of iterative methods for nonlinear, nonsymmetric systems arising in combustion

    SciTech Connect

    Hagstrom, T.; Radhakrishnan, K.

    1994-12-31

    The authors report on some iterative methods which they have tested for use in combustion simulations. In particular, they have developed a code to solve zero Mach number reacting flow equations with complex reaction and diffusion physics. These equations have the form of a nonlinear parabolic system coupled with constraints. In semi-discrete form, one obtains DAE`s of index two or three depending on the number of spatial dimensions. The authors have implemented a fourth order (fully implicit) BDF method in time, coupled with a suite of fourth order explicit and implicit spatial difference approximations. Most codes they know of for simulating reacting flows use a splitting strategy to march in time. This results in a sequence of nonlinear systems to solve, each of which has a simpler structure than the one they are faced with. The rapid and robust solution of the coupled system is the essential requirement for the success of their approach. They have implemented and analyzed nonlinear generalizations of conjugate gradient-like methods for nonsymmetric systems, including CGS and the quasi-Newton based method of Eirola and Nevanlinna. They develop a general framework for the nonlinearization of linear methods in terms of the acceleration of fixed-point iterations, where the latter is assumed to include the {open_quote}preconditioning{open_quote}. Their preconditioning is a single step of a split method, using lower order spatial difference approximations as well as simplified (Fickian) approximations of the diffusion physics.

  9. Experimental methods for the characterization of the frequency-dependent viscoelastic properties of soft materials

    PubMed Central

    Kazemirad, Siavash; K. Heris, Hossein; Mongeau, Luc

    2013-01-01

    A characterization method based on Rayleigh wave propagation was developed for the quantification of the frequency-dependent viscoelastic properties of soft materials at high frequencies; i.e., up to 4 kHz. Planar harmonic surface waves were produced on the surface of silicone rubber samples. The phase and amplitude of the propagating waves were measured at different locations along the propagation direction, which allowed the calculation of the complex Rayleigh wavenumbers at each excitation frequency using a transfer function method. An inverse wave propagation problem was then solved to obtain the complex shear/elastic moduli from the measured wavenumbers. In a separate, related investigation, dynamic indentation tests using atomic force microscopy (AFM) were performed at frequencies up to 300 Hz. No systematic verification study is available for the AFM-based method, which can be used when the dimensions of the test samples are too small for other existing testing methods. The results obtained from the Rayleigh wave propagation and AFM-based indentation methods were compared with those from a well-established method, which involves the generation of standing longitudinal compression waves in rod-shaped test specimens. The results were cross validated and qualitatively confirmed theoretical expectations presented in the literature for the frequency-dependence of polymers. PMID:23654420

  10. Comparison of experimental methods for determination of the volumetric mass transfer coefficient in fermentation processes

    NASA Astrophysics Data System (ADS)

    Tobajas, M.; García-Calvo, E.

    Mass transfer in bioreactors has been examined. In the present work, dynamic methods are used for the determination of KLa values for water, model media and a fermentation broth (Candida utilis) in an airlift reactor. The conventional dynamic method is applied at the end of the microbial process in order to avoid an alteration in the metabolism of the microorganisms. New dynamic methods are used to determine KLa in an airlift reactor during the microbial growth of Candida utilis on glucose. One of the methods is based on the continuous measurement of carbon dioxide production while the other method is based on the relationship between the oxygen transfer and biomass growth rates. These methods of determining KLa does not interfere with the microorganisms action. A theoretical mass transfer model has been used for KLa estimation for the systems described above. Some differences between calculated and measured values are found for fermentation processes due to the model is developed for two-phase air-water systems. Nevertheless, the average deviation between the predicted values and those obtained from the relationship between oxygen transfer and biomass production rates are lower than 25% in any case.

  11. A simple method to assess detonation temperature without using any experimental data and computer code.

    PubMed

    Keshavarz, Mohammad Hossein; Nazari, Hamid Reza

    2006-05-20

    Detonation temperature of C(a)H(b)N(c)O(d) explosives can be predicted from a, b, c, d and calculated gas phase heat of formation of explosives without using any assumed detonation products and experimental data. Two new correlations are introduced for calculation of detonation temperature of aromatic and non-aromatic explosive compounds so that it is shown here how simply calculated heat of formation by additivity rule and atomic composition are only necessary data for this simple prediction. Calculated detonation temperatures by the introduced correlations for both pure and explosive formulations show good agreement with respect to measured detonation temperatures and complicated computer codes. The average mean absolute error in detonation temperature is within about 7.0%.

  12. DETECTORS AND EXPERIMENTAL METHODS: Equivalent properties of single event burnout induced by different sources

    NASA Astrophysics Data System (ADS)

    Yang, Shi-Yu; Cao, Zhou; Da, Dao-An; Xue, Yu-Xiong

    2009-05-01

    The experimental results of single event burnout induced by heavy ions and 252Cf fission fragments in power MOSFET devices have been investigated. It is concluded that the characteristics of single event burnout induced by 252Cf fission fragments is consistent to that in heavy ions. The power MOSFET in the “turn-off" state is more susceptible to single event burnout than it is in the “turn-on" state. The thresholds of the drain-source voltage for single event burnout induced by 173 MeV bromine ions and 252Cf fission fragments are close to each other, and the burnout cross section is sensitive to variation of the drain-source voltage above the threshold of single event burnout. In addition, the current waveforms of single event burnouts induced by different sources are similar. Different power MOSFET devices may have different probabilities for the occurrence of single event burnout.

  13. Fault detection, isolation and reconfiguration in FTMP Methods and experimental results. [fault tolerant multiprocessor

    NASA Technical Reports Server (NTRS)

    Lala, J. H.

    1983-01-01

    The Fault-Tolerant Multiprocessor (FTMP) is a highly reliable computer designed to meet a goal of 10 to the -10th failures per hour and built with the objective of flying an active-control transport aircraft. Fault detection, identification, and recovery software is described, and experimental results obtained by injecting faults in the pin level in the FTMP are presented. Over 21,000 faults were injected in the CPU, memory, bus interface circuits, and error detection, masking, and error reporting circuits of one LRU of the multiprocessor. Detection, isolation, and reconfiguration times were recorded for each fault, and the results were found to agree well with earlier assumptions made in reliability modeling.

  14. New method in experimental damage study of AS4/PEEK composite laminates

    NASA Astrophysics Data System (ADS)

    Wang, Shibin; Tong, Jingwei; Yue, C.; Li, Linan; Shen, Min

    2002-06-01

    AS4/PEEK [0/+/- 45/90]7s composite laminates were subjected to a bending moment. We have obtained the displacement fields by moire interferometry with the aid of Long Distance Microscope. Based on wavelet analysis, the digital moire images were processed and analyzed. The special algorithms of unconstrained nonlinear minimization and the scale parameter were used to eliminate the influence of the noise in the digital image processing. Tension tests were carried out on AS4/PEEK [ 0/+/- 45/90 ]2s composites. When AS4/PEEK composite laminates were deformed, the images of natural surface of the AS4/PEEK specimen were recorded to study the damage initiation and growth. The experimental results show that the considerable interlaminal stresses between different plies, and these places were more prone to delaminate. The paper presents the microscopic damages and matrix crack growth observed by an optical microscope and the CCD camera.

  15. Experimental verification of a membrane humidifier model based on the effectiveness method

    NASA Astrophysics Data System (ADS)

    Kadylak, David; Mérida, Walter

    Experiments conducted on a commercial fuel cell humidifier determined that the water recovery ratio is the best performance metric because it considers the water supplied to the humidifier. Data from a porous polymer membrane with a hydrophilic additive were analyzed under a heat and mass transfer model. The membrane showed low water uptake profiles at relative humidities below 80 percent, and a steep increase in water uptake above threshold. The experiments were conducted with samples of the porous membrane in a single cell humidifier at isothermal conditions at temperatures of 25, 50, and 75 °C. The water recovery ratio for the porous membrane decreased with increasing flow rate. The model was verified experimentally and its predictions agreed with the measured data.

  16. Fault detection, isolation and reconfiguration in FTMP Methods and experimental results. [fault tolerant multiprocessor

    NASA Technical Reports Server (NTRS)

    Lala, J. H.

    1983-01-01

    The Fault-Tolerant Multiprocessor (FTMP) is a highly reliable computer designed to meet a goal of 10 to the -10th failures per hour and built with the objective of flying an active-control transport aircraft. Fault detection, identification, and recovery software is described, and experimental results obtained by injecting faults in the pin level in the FTMP are presented. Over 21,000 faults were injected in the CPU, memory, bus interface circuits, and error detection, masking, and error reporting circuits of one LRU of the multiprocessor. Detection, isolation, and reconfiguration times were recorded for each fault, and the results were found to agree well with earlier assumptions made in reliability modeling.

  17. A dynamic method to forecast the wheel slip for antilock braking system and its experimental evaluation.

    PubMed

    Oniz, Yesim; Kayacan, Erdal; Kaynak, Okyay

    2009-04-01

    The control of an antilock braking system (ABS) is a difficult problem due to its strongly nonlinear and uncertain characteristics. To overcome this difficulty, the integration of gray-system theory and sliding-mode control is proposed in this paper. This way, the prediction capabilities of the former and the robustness of the latter are combined to regulate optimal wheel slip depending on the vehicle forward velocity. The design approach described is novel, considering that a point, rather than a line, is used as the sliding control surface. The control algorithm is derived and subsequently tested on a quarter vehicle model. Encouraged by the simulation results indicating the ability to overcome the stated difficulties with fast convergence, experimental results are carried out on a laboratory setup. The results presented indicate the potential of the approach in handling difficult real-time control problems.

  18. Experimental study of novel passive control methods to improve combustor exit temperature uniformity

    NASA Astrophysics Data System (ADS)

    Gupta, Alka; Ibrahim, Mohamed Saeed; Amano, R. S.

    2015-01-01

    The effect of non-uniform temperature flow which comes in contact with the turbine blades is of paramount importance since the thermal damage that occur to the blade during its operation, is governed by the non-uniformities present in the oncoming flow. This thermal damage leads to increased maintenance cost and reduced life-span of the turbine blades. This paper investigates the effectiveness of some novel passive control techniques to improve the temperature uniformity of the combustor exit flow to address the need to reduce the thermal damage and hence decrease the overall maintenance cost of the gas turbine system. The novel passive control techniques tested in this study include the use of streamlined body or guide vanes in the dilution zone of the combustor. For the guide vanes four different orientations were tested—0°, 30°, 60°, 90°. Extensive experimentation was conducted under different flow conditions. The deviation of the exit temperature from the equilibrium mixing temperature was used to compare the effectiveness of different passive control techniques. It was found that the 30o guide vanes gave the most uniform temperature flow under majority of cases considered. On an average, the flow with 30o guide vanes was about 15 % more uniform in temperature as compared to the staggered holes geometry with only 1 % higher pressure loss. The possible reason for this improvement is the combination of swirl and depth to which the dilution flow can enter the dilution zone and mix with the primary hot flow. The streamlined body came second with an improvement in pressure losses. Based on these experimental findings, the use of these guide vanes and streamlined body has potential in the gas turbine industry to deal with the high maintenance cost involved in these systems.

  19. Quantitative PCR and unconventional serological methods to evaluate clomipramine treatment effectiveness in experimental Trypanosoma cruzi infection.

    PubMed

    Bazán, Paola Carolina; Lo Presti, María Silvina; Strauss, Mariana; Báez, Alejandra Lidia; Miler, Noemí; Paglini, Patricia Adriana; Rivarola, Héctor Walter

    2016-10-01

    Clomipramine (CLO), a tricyclic antidepressant drug, has been used for the treatment of mice infected with Trypanosoma cruzi. In this work we evaluated the effectiveness of CLO treatment upon T. cruzi-infected mice in the chronic phase of the experimental infection using Quantitative polymerase chain reaction (qPCR) and recombinant ELISA. Sixty Swiss albino mice were inoculated with 50 trypomastigote forms of T. cruzi (Tulahuen strain). CLO treatment consisted of 5mg/kg/day during 60days by intraperitoneal injection, beginning on day 90 post infection (p.i) when the mice presented electrocardiographic (ECG) alterations compatible with the chronic phase of the disease. The evolution of experimental infection and the treatment efficacy were studied through survival, electrocardiography, serology using a mixture and individual (1, 2, 13, 30, 36 and SAPA) recombinant proteins from epimastigotes and trypomastigotes of T. cruzi; and qPCR on days 180 and 270 p.i. CLO treatment in the chronic phase decreased the parasite load, reduced the levels of antibodies against antigen 13 throughout 270days p.i and reversed the ECG abnormalities in the treated animals, from 100% of the mice with alterations at the beginning of the treatment to only 20% of the mice with alterations by day 270 p.i. This study shows that qPCR and the use of recombinant antigens are more sensitive to evaluate the effectiveness of the treatment and proves that clomipramine may be considered as a new chemotherapy for the chronic phase of the disease. Copyright © 2016. Published by Elsevier Inc.

  20. Head injury assessment of non-lethal projectile impacts: A combined experimental/computational method.

    PubMed

    Sahoo, Debasis; Robbe, Cyril; Deck, Caroline; Meyer, Frank; Papy, Alexandre; Willinger, Remy

    2016-11-01

    The main objective of this study is to develop a methodology to assess this risk based on experimental tests versus numerical predictive head injury simulations. A total of 16 non-lethal projectiles (NLP) impacts were conducted with rigid force plate at three different ranges of impact velocity (120, 72 and 55m/s) and the force/deformation-time data were used for the validation of finite element (FE) NLP. A good accordance between experimental and simulation data were obtained during validation of FE NLP with high correlation value (>0.98) and peak force discrepancy of less than 3%. A state-of-the art finite element head model with enhanced brain and skull material laws and specific head injury criteria was used for numerical computation of NLP impacts. Frontal and lateral FE NLP impacts to the head model at different velocities were performed under LS-DYNA. It is the very first time that the lethality of NLP is assessed by axonal strain computation to predict diffuse axonal injury (DAI) in NLP impacts to head. In case of temporo-parietal impact the min-max risk of DAI is 0-86%. With a velocity above 99.2m/s there is greater than 50% risk of DAI for temporo-parietal impacts. All the medium- and high-velocity impacts are susceptible to skull fracture, with a percentage risk higher than 90%. This study provides tool for a realistic injury (DAI and skull fracture) assessment during NLP impacts to the human head. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. A new experimental method for measuring life time and crack growth of materials under multi-stage and random loadings.

    PubMed

    Stanzl, S

    1981-11-01

    The experimental equipment and method of operation of a special computer-controlled fatigue testing machine is described. This resonance testing machine, operating at ultrasonic frequencies (20 kHz), performs one-step, multistage, and random fatigue tests with the aid of a computerized control system in very short testing times. Differences between this method and testing procedure at conventional frequencies are pointed out. However, it is emphasized that the high frequency tests have practical merit aside from lower energy cost and testing times. Initial results of two-stage fatigue experiments are reported.

  2. Network topology and parameter estimation: from experimental design methods to gene regulatory network kinetics using a community based approach

    PubMed Central

    2014-01-01

    Background Accurate estimation of parameters of biochemical models is required to characterize the dynamics of molecular processes. This problem is intimately linked to identifying the most informative experiments for accomplishing such tasks. While significant progress has been made, effective experimental strategies for parameter identification and for distinguishing among alternative network topologies remain unclear. We approached these questions in an unbiased manner using a unique community-based approach in the context of the DREAM initiative (Dialogue for Reverse Engineering Assessment of Methods). We created an in silico test framework under which participants could probe a network with hidden parameters by requesting a range of experimental assays; results of these experiments were simulated according to a model of network dynamics only partially revealed to participants. Results We proposed two challenges; in the first, participants were given the topology and underlying biochemical structure of a 9-gene regulatory network and were asked to determine its parameter values. In the second challenge, participants were given an incomplete topology with 11 genes and asked to find three missing links in the model. In both challenges, a budget was provided to buy experimental data generated in silico with the model and mimicking the features of different common experimental techniques, such as microarrays and fluorescence microscopy. Data could be bought at any stage, allowing participants to implement an iterative loop of experiments and computation. Conclusions A total of 19 teams participated in this competition. The results suggest that the combination of state-of-the-art parameter estimation and a varied set of experimental methods using a few datasets, mostly fluorescence imaging data, can accurately determine parameters of biochemical models of gene regulation. However, the task is considerably more difficult if the gene network topology is not completely

  3. Improved dispersion method of multi-wall carbon nanotube for inhalation toxicity studies of experimental animals.

    PubMed

    Taquahashi, Yuhji; Ogawa, Yukio; Takagi, Atsuya; Tsuji, Masaki; Morita, Koichi; Kanno, Jun

    2013-01-01

    A multi-wall carbon nanotube (MWCNT) product Mitsui MWNT-7 is a mixture of dispersed single fibers and their agglomerates/aggregates. In rodents, installation of such mixture induces inflammatory lesions triggered predominantly by the aggregates/agglomerates at the level of terminal bronchiole of the lungs. In human, however, pulmonary toxicity induced by dispersed single fibers that reached the lung alveoli is most important to assess. Therefore, a method to generate aerosol predominantly consisting of dispersed single fibers without changing their length and width is needed for inhalation studies. Here, we report a method (designated as Taquann method) to effectively remove the aggregate/agglomerates and enrich the well-dispersed singler fibers in dry state without dispersant and without changing the length and width distribution of the single fibers. This method is base on two major concept; liquid-phase fine filtration and critical point drying to avoid re-aggregation by surface tension. MWNT-7 was suspended in Tert-butyl alcohol, freeze-and-thawed, filtered by a vibrating 25 µm mesh Metallic Sieve, snap-frozen by liquid nitrogen, and vacuum-sublimated (an alternative method to carbon dioxide critical point drying). A newly designed direct injection system generated well-dispersed aerosol in an inhalation chamber. The lung of mice exposed to the aerosol contained single fibers with a length distribution similar to the original and the Taquann-treated sample. Taquann method utilizes inexpensive materials and equipments mostly found in common biological laboratories, and prepares dry powder ready to make well-dispersed aerosol. This method and the chamber with direct injection system would facilitate the inhalation toxicity studies more relevant to human exposure.

  4. A Comparison of 1D and 2D (Unbiased) Experimental Methods for Measuring CSAsolarDD Cross-Correlated Relaxation

    NASA Astrophysics Data System (ADS)

    Batta, Gy.; Kövér, K. E.; Kowalewski, J.

    1999-01-01

    Conventional and enhanced 1D experiments and different NOESY experiments (the 2D unbiased method) were performed for measuring CSA/DD cross-correlated relaxation on trehalose, a compound which could be approximated as a spherical top, and on simple model compounds comprisingC3vsymmetry (CHCl3, triphenylsilane (TPSi)). The comparison gives experimental evidence for the equivalence of the methods within the limits of the two-spin approach. 1D data are evaluated with both the simple initial rate and the Redfield relaxation matrix approach. The 2D data are obtained from the so-called transfer matrix using the Perrin-Gipe eigenvalue/eigenvector method. For the improved performance of the 2D method, anX-filtered (HHH) NOESY is suggested at the natural abundance of13C (or other dilute, low γ species). Also, experimental parameters crucial for reliable CSA data are tested (e.g., the impact of insufficient relaxation delay). Error estimation is carried out for fair comparison of methods. Revised liquid state1H and13C (29Si) CSA data are presented for chloroform and TPSi.

  5. Modern methods of experimental construction of texture complete direct pole figures by using X-ray data

    NASA Astrophysics Data System (ADS)

    Isaenkova, M.; Perlovich, Yu; Fesenko, V.

    2016-04-01

    Currently used methods for constructing texture complete direct pole figure (CDPF) based on the results of X-ray diffractometric measurements were considered with respect to the products of Zr-based alloys and, in particular, used in a nuclear reactor cladding tubes, for which the accuracy of determination of integral texture parameters is of the especial importance. The main attention was devoted to technical issues which are solved by means of computer processing of large arrays of obtained experimental data. Among considered questions there are amendments of the defocusing, techniques for constructing of complete direct pole figures and determination of integral textural parameters. The methods of reconstruction of complete direct pole figures by partial direct pole figures recorded up to tilt angles of sample ψ=70-80°: the method of extrapolation of data to an uninvestigated region of the stereographic projection, and the method of "sewing" of partial pole figures measured for three mutually perpendicular plane sections of the product. The limits of applicability of these methods, depending on the shape of the test product and the degree of inhomogeneity of the layer-by-layer texture, were revealed. On the basis of a large number of experimental data, the accuracy of the integral parameters used for calculation of the physical and mechanical properties of metals with a hexagonal crystal structure was found to be equal to 0.02, when taking into account the texture heterogeneity of regular products from Zr-based alloys.

  6. Novel method and experimental validation of statistical calibration via Gaussianization in hot-wire anemometry

    NASA Astrophysics Data System (ADS)

    Gluzman, Igal; Cohen, Jacob; Oshman, Yaakov

    2016-11-01

    We introduce a statistical method based on Gaussianization to estimate the nonlinear calibration curve of a hot-wire probe, that relates the input flow velocity to the output (measured) voltage. The method uses as input a measured sequence of voltage samples, corresponding to different unknown flow velocities in the desired operational range, and only two measured voltages along with their known (calibrated) flow velocities. The novel method is validated against standard calibration methods using data acquired by hot-wire probes using wind-tunnel experiments. We demonstrate our new calibration technique by placing the hot-wire probe at certain region downstream of a cube-shaped body in a free stream of air flow. For testing our calibration method we rely on flow statistics that exist, among others, in a certain region of a turbulent wake formed downstream of the cube-shaped body. The specific properties are: first, the velocity signal in the wake should be as close to Gaussian as possible. Second, the signal should cover the desired velocity range that should be calibrated. The appropriate region to place our probe is determined via computation of the first four statistical moments of the measured signals in different regions of the wake.

  7. Experimental verification of prediction method for electromigration failure of polycrystalline lines

    NASA Astrophysics Data System (ADS)

    Sasagawa, Kazuhiko; Naito, Kazushi; Kimura, Hiroki; Saka, Masumi; Abé, Hiroyuki

    2000-03-01

    A prediction method for electromigration failure in polycrystalline lines has been proposed using the governing parameter of electromigration damage, the atomic flux divergence (AFDgen), and the usefulness has been verified by experiment where various line shapes were treated under various operating conditions. In the prediction method, lifetime and failure site in a metal line have been predicted by numerical simulation of the processes of void initiation, its growth, to line failure. The simulation has predicted accurately the lifetime as well as the failure site of the metal line. In the verification, however, the metal lines treated had the same grain size, that is, the same microstructure. In this article, the prediction method for the electromigration failure of polycrystalline lines was verified in more detail, by comparing the prediction results of lifetime and failure site with the results of experiments using not only various shaped lines but also lines whose microstructures were different.

  8. Optimization and Experimentation of Dual-Mass MEMS Gyroscope Quadrature Error Correction Methods.

    PubMed

    Cao, Huiliang; Li, Hongsheng; Kou, Zhiwei; Shi, Yunbo; Tang, Jun; Ma, Zongmin; Shen, Chong; Liu, Jun

    2016-01-07

    This paper focuses on an optimal quadrature error correction method for the dual-mass MEMS gyroscope, in order to reduce the long term bias drift. It is known that the coupling stiffness and demodulation error are important elements causing bias drift. The coupling stiffness in dual-mass structures is analyzed. The experiment proves that the left and right masses' quadrature errors are different, and the quadrature correction system should be arranged independently. The process leading to quadrature error is proposed, and the Charge Injecting Correction (CIC), Quadrature Force Correction (QFC) and Coupling Stiffness Correction (CSC) methods are introduced. The correction objects of these three methods are the quadrature error signal, force and the coupling stiffness, respectively. The three methods are investigated through control theory analysis, model simulation and circuit experiments, and the results support the theoretical analysis. The bias stability results based on CIC, QFC and CSC are 48 °/h, 9.9 °/h and 3.7 °/h, respectively, and this value is 38 °/h before quadrature error correction. The CSC method is proved to be the better method for quadrature correction, and it improves the Angle Random Walking (ARW) value, increasing it from 0.66 °/√h to 0.21 °/√h. The CSC system general test results show that it works well across the full temperature range, and the bias stabilities of the six groups' output data are 3.8 °/h, 3.6 °/h, 3.4 °/h, 3.1 °/h, 3.0 °/h and 4.2 °/h, respectively, which proves the system has excellent repeatability.

  9. Optimization and Experimentation of Dual-Mass MEMS Gyroscope Quadrature Error Correction Methods

    PubMed Central

    Cao, Huiliang; Li, Hongsheng; Kou, Zhiwei; Shi, Yunbo; Tang, Jun; Ma, Zongmin; Shen, Chong; Liu, Jun

    2016-01-01

    This paper focuses on an optimal quadrature error correction method for the dual-mass MEMS gyroscope, in order to reduce the long term bias drift. It is known that the coupling stiffness and demodulation error are important elements causing bias drift. The coupling stiffness in dual-mass structures is analyzed. The experiment proves that the left and right masses’ quadrature errors are different, and the quadrature correction system should be arranged independently. The process leading to quadrature error is proposed, and the Charge Injecting Correction (CIC), Quadrature Force Correction (QFC) and Coupling Stiffness Correction (CSC) methods are introduced. The correction objects of these three methods are the quadrature error signal, force and the coupling stiffness, respectively. The three methods are investigated through control theory analysis, model simulation and circuit experiments, and the results support the theoretical analysis. The bias stability results based on CIC, QFC and CSC are 48 °/h, 9.9 °/h and 3.7 °/h, respectively, and this value is 38 °/h before quadrature error correction. The CSC method is proved to be the better method for quadrature correction, and it improves the Angle Random Walking (ARW) value, increasing it from 0.66 °/√h to 0.21 °/√h. The CSC system general test results show that it works well across the full temperature range, and the bias stabilities of the six groups’ output data are 3.8 °/h, 3.6 °/h, 3.4 °/h, 3.1 °/h, 3.0 °/h and 4.2 °/h, respectively, which proves the system has excellent repeatability. PMID:26751455

  10. The Parallel Asynchronous Differential Evolution Method as a Tool to Analyze Synchrotron Scattering Experimental Data from Vesicular Systems

    NASA Astrophysics Data System (ADS)

    Zhabitskaya, Evgeniya; Zemlyanaya, Elena; Kiselev, Mikhail; Gruzinov, Andrey

    2016-02-01

    In this work we use an Asynchronous Differential Evolution (ADE) method to estimate parameters of the Separated Form Factor (SFF) model which is used to investigate a structure of drug delivery Phospholipid Transport Nano System (PTNS) unilamellar vesicles by experimental small angle synchrotron X-ray scattering spectra (SAXS). We compare the efficiency of different optimizing procedures (OP) for the search for the SFF-model parameters. It is shown that the probability to find the global solution of this problem by ADE-methods is significantly higher than that by either Nelder-Mead method or a Quasi-Newton method with Davidon-Fletcher-Powell formula. The parallel realization of ADE accelerates the calculations significantly. The speed-up obtained by the parallel realization of ADE and results of the model are presented. The work has been performed under the grant of Russian Scientific Foundation (project No 14-12-00516)

  11. A Comparative Study of Information-Based Source Number Estimation Methods and Experimental Validations on Mechanical Systems

    PubMed Central

    Cheng, Wei; Zhang, Zhousuo; Cao, Hongrui; He, Zhengjia; Zhu, Guanwen

    2014-01-01

    This paper investigates one eigenvalue decomposition-based source number estimation method, and three information-based source number estimation methods, namely the Akaike Information Criterion (AIC), Minimum Description Length (MDL) and Bayesian Information Criterion (BIC), and improves BIC as Improved BIC (IBIC) to make it more efficient and easier for calculation. The performances of the abovementioned source number estimation methods are studied comparatively with numerical case studies, which contain a linear superposition case and a both linear superposition and nonlinear modulation mixing case. A test bed with three sound sources is constructed to test the performances of these methods on mechanical systems, and source separation is carried out to validate the effectiveness of the experimental studies. This work can benefit model order selection, complexity analysis of a system, and applications of source separation to mechanical systems for condition monitoring and fault diagnosis purposes. PMID:24776935

  12. Theoretical and experimental dynamic analysis aimed at the improvement of an acoustic method for fresco detachment diagnosis

    NASA Astrophysics Data System (ADS)

    Del Vescovo, Dionisio; Fregolent, Annalisa

    2009-10-01

    An acoustic non-invasive method for the diagnosis of detachment in frescos was previously proposed by the authors. This method is based on the indirect evaluation of the vibrations due to detachments, by means of a surface inspection. In this paper the relations between the dynamics of the structure to be inspected and the operational principles of the acoustic method of diagnosis are presented. The dynamic analysis is carried out using experimental investigations and analytical and numerical models. It shows that the quality of the diagnosis depends on the capability of the acoustic device to excite the structural resonances related to the detachments. These results are useful for future improvements, in particular to enhance the sensitivity of the proposed method.

  13. A comparative study of information-based source number estimation methods and experimental validations on mechanical systems.

    PubMed

    Cheng, Wei; Zhang, Zhousuo; Cao, Hongrui; He, Zhengjia; Zhu, Guanwen

    2014-04-25

    This paper investigates one eigenvalue decomposition-based source number estimation method, and three information-based source number estimation methods, namely the Akaike Information Criterion (AIC), Minimum Description Length (MDL) and Bayesian Information Criterion (BIC), and improves BIC as Improved BIC (IBIC) to make it more efficient and easier for calculation. The performances of the abovementioned source number estimation methods are studied comparatively with numerical case studies, which contain a linear superposition case and a both linear superposition and nonlinear modulation mixing case. A test bed with three sound sources is constructed to test the performances of these methods on mechanical systems, and source separation is carried out to validate the effectiveness of the experimental studies. This work can benefit model order selection, complexity analysis of a system, and applications of source separation to mechanical systems for condition monitoring and fault diagnosis purposes.

  14. Experimental studies of the properties of 'simulated' upstream turbulence using a statistical multipoint method

    NASA Technical Reports Server (NTRS)

    Orlowski, D. S.; Le, G.; Russell, C. T.; Krauss-Varban, D.; Omidi, N.

    1995-01-01

    In this report we present a different approach to the multipoint measurement of magnetic fields and plasma. This is called the multi-spacecraft ensemble technique (MET), essentially free of process restrictions, such as linearity and stationarity. We comprehensively discuss the other conditions and limitations intrinsic to this statistical method. We also show the results of the application of the ensemble method to the synthetic data obtained from a hybrid simulation in the region upstream of a quasi-parallel shock. The important implications of the above approach for the CLUSTER mission are discussed.

  15. Experimental studies of the properties of 'simulated' upstream turbulence using a statistical multipoint method

    NASA Technical Reports Server (NTRS)

    Orlowski, D. S.; Le, G.; Russell, C. T.; Krauss-Varban, D.; Omidi, N.

    1995-01-01

    In this report we present a different approach to the multipoint measurement of magnetic fields and plasma. This is called the multi-spacecraft ensemble technique (MET), essentially free of process restrictions, such as linearity and stationarity. We comprehensively discuss the other conditions and limitations intrinsic to this statistical method. We also show the results of the application of the ensemble method to the synthetic data obtained from a hybrid simulation in the region upstream of a quasi-parallel shock. The important implications of the above approach for the CLUSTER mission are discussed.

  16. Experimental Pi.

    ERIC Educational Resources Information Center

    Corris, G.

    1990-01-01

    Discusses the calculation of pi by means of experimental methods. Polygon circle ratios, Archimedes' method, Buffon's needles, a Monte Carlo method, and prime number approaches are used. Presents three BASIC programs for the calculations. (YP)

  17. Experimental Pi.

    ERIC Educational Resources Information Center

    Corris, G.

    1990-01-01

    Discusses the calculation of pi by means of experimental methods. Polygon circle ratios, Archimedes' method, Buffon's needles, a Monte Carlo method, and prime number approaches are used. Presents three BASIC programs for the calculations. (YP)

  18. Development of method for experimental determination of wheel-rail contact forces and contact point position by using instrumented wheelset

    NASA Astrophysics Data System (ADS)

    Bižić, Milan B.; Petrović, Dragan Z.; Tomić, Miloš C.; Djinović, Zoran V.

    2017-07-01

    This paper presents the development of a unique method for experimental determination of wheel-rail contact forces and contact point position by using the instrumented wheelset (IWS). Solutions of key problems in the development of IWS are proposed, such as the determination of optimal locations, layout, number and way of connecting strain gauges as well as the development of an inverse identification algorithm (IIA). The base for the solution of these problems is the wheel model and results of FEM calculations, while IIA is based on the method of blind source separation using independent component analysis. In the first phase, the developed method was tested on a wheel model and a high accuracy was obtained (deviations of parameters obtained with IIA and really applied parameters in the model are less than 2%). In the second phase, experimental tests on the real object or IWS were carried out. The signal-to-noise ratio was identified as the main influential parameter on the measurement accuracy. Тhе obtained results have shown that the developed method enables measurement of vertical and lateral wheel-rail contact forces Q and Y and their ratio Y/Q with estimated errors of less than 10%, while the estimated measurement error of contact point position is less than 15%. At flange contact and higher values of ratio Y/Q or Y force, the measurement errors are reduced, which is extremely important for the reliability and quality of experimental tests of safety against derailment of railway vehicles according to the standards UIC 518 and EN 14363. The obtained results have shown that the proposed method can be successfully applied in solving the problem of high accuracy measurement of wheel-rail contact forces and contact point position using IWS.

  19. Experimental research of methods for clustering and selecting image fragments using spatial invariant equivalent models

    NASA Astrophysics Data System (ADS)

    Krasilenko, Vladimir G.; Lazarev, Alexander A.; Nikitovich, Diana V.

    2014-08-01

    In the paper, we show that the nonlinear spatial non-linear equivalency functions on the basis of continuous logic equivalence (nonequivalence) operations have better discriminatory properties for comparing images. Further, using the equivalent model of multiport neural networks and associative memory, (including matrix-matrix and matrix-tensor with adaptive-weighted correlation, multi-port neural-net auto-associative and hetero-associative memory (MP NN AAM and HAM ) and the proposed architecture based on them, we show how we can modify these models and architectures for space-invariant associative recognition and clustering (high performance parallel clustering processing) images. We consider possible implementations of 2D image classifiers, devices for partitioning image fragments into clusters and their architectures. The main base unit of such architectures is a matrix-matrix or matrix-tensor equivalentor, which can be implemented on the basis of two traditional correlators. We show that the classifiers based on the equivalency paradigm and optoelectronic architectures with space-time integration and parallel-serial 2D images processing have advantages such as increased memory capacity (more than ten times of the number of neurons!), High performance in different modes . We present the results of associative significant dimension (128x128, 610x340) image recognition - renewal modeling. It will be shown that these models are capable to recognize images with a significant percentage (20- 30%) damaged pixels. The experimental results show that such models can be successfully used for auto-and heteroassociative pattern recognition. We show simulation results of using these modifications for clustering and learning models and algorithms for cluster analysis of specific images and divide them into categories of the array. Show example of a cluster division of image fragments, letters and graphics for clusters with simultaneous formation of the outputweighted spatial

  20. Aligning Experimental and Theoretical Anisotropic B-Factors: Water Models, Normal-Mode Analysis Methods, and Metrics

    PubMed Central

    2014-01-01

    The strength of X-ray crystallography in providing the information for protein dynamics has been under appreciated. The anisotropic B-factors (ADPs) from high-resolution structures are invaluable in studying the relationship among structure, dynamics, and function. Here, starting from an in-depth evaluation of the metrics used for comparing the overlap between two ellipsoids, we applied normal-mode analysis (NMA) to predict the theoretical ADPs and then align them with experimental results. Adding an extra layer of explicitly treated water on protein surface significantly improved the energy minimization results and better reproduced the anisotropy of experimental ADPs. In comparing experimental and theoretical ADPs, we focused on the overlap in shape, the alignment of dominant directions, and the similarity in magnitude. The choices of water molecules, NMA methods, and the metrics for evaluating the overlap of ADPs determined final results. This study provides useful information for exploring the physical basis and the application potential of experimental ADPs. PMID:24673391

  1. Establishment of a new pull-out strength testing method to quantify early osseointegration-An experimental pilot study.

    PubMed

    Nonhoff, J; Moest, T; Schmitt, Christian Martin; Weisel, T; Bauer, S; Schlegel, K A

    2015-12-01

    The animal study aims to evaluate a new experimental model for measuring sole the influence of the surface characteristics independent from implant macro-design on the level of osseointegration by registering the pull-out strength needed for removal of experimental devices with different surfaces from artificial defects. Seventy-two test bodies (36 with the FRIADENT(®) plus surface, 36 with the P15/HAp biofunctionalized surface) were inserted in six adult domestic pigs with artificial calvarial defects. The experimental devices were designed to fit in the defects leaving a gap between the test body and the local bone. After 21 days of healing, the animals were sacrificed and the test bodies were pulled out with a standardised reproducible pull-out device measuring the pull-out strength. The pull-out strength for both groups was compared. Twenty-one days after insertion a mean force of 412 ± 142 N for the P15/HAp group and 183 ± 105 N for the FRIADENT(®) plus group was measured for the removal of the specimens from the calvarial bone. The difference between the groups was statistically significant (p < 0.0001). The experimental set-up seems to be a suitable method when measuring the impact of implant surfaces on the early stage of osseointegration. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  2. Identifying experimental methods to determine the effect of pain on attention: a review of pain, caffeine, alcohol and nicotine studies.

    PubMed

    Moore, David J; Keogh, Edmund; Eccleston, Christopher

    2009-12-01

    To review published studies of the effects that pain and common psychopharmacological substances have on the attentional performance of healthy adults. To identify which attentional tasks have the greatest potential to investigate the effect of pain on attention and provide recommendations for future research. A search was conducted for reports of experimental studies of attention in the context of pain. This was supplemented with studies on attention and caffeine, nicotine and alcohol. Studies were included if they used a healthy adult sample, used experimental or quasi-experimental methods, were relevant to the study of attention or interruption of pain and/or examined the acute effects of a substance on attention. Thirty-two papers, with 49 different experimental studies were identified (12 pain, 21 nicotine, 7 caffeine, 9 alcohol). Fourteen different tasks were reviewed across six domains of attention. The most promising measures of attention were the continuous performance task, flanker task, endogenous pre-cuing task, n-back task, inhibition task and dual task. There are reliable tasks that could be used to determine the effects of pain on attention. Future research is required that develops the utility of these tasks to improve our understanding of the effects pain and analgesia have on attentional performance. Copyright (c) 2009 John Wiley & Sons, Ltd.

  3. Experimental Evaluation of Design Methods for Hardened Piping Systems. Schedule D. Volume II.

    DTIC Science & Technology

    prediction capabilities of present day computer methods. The basic pipe elements tested included straight pipes, area changes, elbows , values, a pump, and...surge tanks. The piping system tested was a closed loop system which contained the following elements: elbows , straight pipes, values, a pump, and an

  4. Tools and Methods to Create Scenarios for Experimental Research in the Network Science Research Laboratory (NSRL)

    DTIC Science & Technology

    2015-12-01

    final phase (Visualization), tools and methods for visualizing and running the scenario are outlined. Although this report does not go into the full...command: emaneeventservice eventservice.xml -l 4 Approved for public release; distribution unlimited. 10 Going back to the CORE window, you

  5. Do Different Training Conditions Facilitate Team Implementation? A Quasi-Experimental Mixed Methods Study

    ERIC Educational Resources Information Center

    Nielsen, Karina; Randall, Raymond; Christensen, Karl B.

    2017-01-01

    A mixed methods approach was applied to examine the effects of a naturally occurring teamwork intervention supported with training. The first objective was to integrate qualitative process evaluation and quantitative effect evaluation to examine "how" and "why" the training influence intervention outcomes. The intervention (N =…

  6. The Editor's Manipulation of Photographs: An Experimental Study of the Effect of Varying Reproduction Methods.

    ERIC Educational Resources Information Center

    Fosdick, James A.; Shoemaker, Pamela J.

    A study was conducted to determine the effect on perceived meaning of the way a photograph is reproduced and to discover whether there would be an interaction between the complexity of photographic subject matter and the complexity of reproduction method. Each of 160 college students in a sophomore-level American history course was given a packet…

  7. Performance Analysis and Experimental Validation of the Direct Strain Imaging Method

    Treesearch

    Athanasios Iliopoulos; John G. Michopoulos; John C. Hermanson

    2013-01-01

    Direct Strain Imaging accomplishes full field measurement of the strain tensor on the surface of a deforming body, by utilizing arbitrarily oriented engineering strain measurements originating from digital imaging. In this paper an evaluation of the method’s performance with respect to its operating parameter space is presented along with a preliminary...

  8. A direct comparison of experimental methods to measure dimensions of synthetic nanoparticles.

    PubMed

    Eaton, P; Quaresma, P; Soares, C; Neves, C; de Almeida, M P; Pereira, E; West, P

    2017-11-01

    Nanoparticles have properties that depend critically on their dimensions. There are a large number of methods that are commonly used to characterize these dimensions, but there is no clear consensus on which method is most appropriate for different types of nanoparticles. In this work four different characterization methods that are commonly applied to characterize the dimensions of nanoparticles either in solution or dried from solution are critically compared. Namely, transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), and dynamic light scattering (DLS) are compared with one another. The accuracy and precision of the four methods applied nanoparticles of different sizes composed of three different core materials, namely gold, silica, and polystyrene are determined. The suitability of the techniques to discriminate different populations of these nanoparticles in mixtures are also studied. The results indicate that in general, scanning electron microscopy is suitable for large nanoparticles (above 50 nm in diameter), while AFM and TEM can also give accurate results with smaller nanoparticles. DLS reveals details about the particles' solution dynamics, but is inappropriate for polydisperse samples, or mixtures of differently sized samples. SEM was also found to be more suitable to metallic particles, compared to oxide-based and polymeric nanoparticles. The conclusions drawn from the data in this paper can help nanoparticle researchers choose the most appropriate technique to characterize the dimensions of nanoparticle samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Developing information literacy skills in pre-registration nurses: an experimental study of teaching methods.

    PubMed

    Brettle, Alison; Raynor, Michael

    2013-02-01

    To compare the effectiveness of an online information literacy tutorial with a face-to-face session for teaching information literacy skills to nurses. Randomised control trial. Seventy-seven first year undergraduate pre-registration diploma nursing students. Online in-house information literacy tutorial One hour face-to-face session, covering the same material as the intervention, delivered by the nursing subject librarian. Search histories were scored using a validated checklist covering keyword selection, boolean operators, truncation and synonyms. Skills retention was measured at 1 month using the same checklist. Inferential statistics were used to compare search skills within and between groups pre and post-session. The searching skills of first year pre-registration nursing students improve following information literacy sessions (p<0.001), and remain unchanged 1 month later, regardless of teaching method. The two methods produce a comparable improvement (p=0.263). There is no improvement or degradation of skills 1 month post-session for either method (p=0.216). Nurses Information literacy skills improve after both face-to-face and online instruction. There is no skills degradation at 1 month post-intervention for either method. Copyright © 2011. Published by Elsevier Ltd.

  10. Modeling and Experimental Methods to Probe the Link between Global Transcription and Spatial Organization of Chromosomes

    PubMed Central

    Gupta, Soumya; Libchaber, Albert; Tlusty, Tsvi; Shivashankar, G. V.

    2012-01-01

    Genomes are spatially assembled into chromosome territories (CT) within the nucleus of living cells. Recent evidences have suggested associations between three-dimensional organization of CTs and the active gene clusters within neighboring CTs. These gene clusters are part of signaling networks sharing similar transcription factor or other downstream transcription machineries. Hence, presence of such gene clusters of active signaling networks in a cell type may regulate the spatial organization of chromosomes in the nucleus. However, given the probabilistic nature of chromosome positions and complex transcription factor networks (TFNs), quantitative methods to establish their correlation is lacking. In this paper, we use chromosome positions and gene expression profiles in interphase fibroblasts and describe methods to capture the correspondence between their spatial position and expression. In addition, numerical simulations designed to incorporate the interacting TFNs, reveal that the chromosome positions are also optimized for the activity of these networks. These methods were validated for specific chromosome pairs mapped in two distinct transcriptional states of T-Cells (naïve and activated). Taken together, our methods highlight the functional coupling between topology of chromosomes and their respective gene expression patterns. PMID:23049710

  11. A new method for experimental determination of the series resistance of a solar cell

    SciTech Connect

    Araujo, G.L.; Sanchez, E.

    1982-10-01

    A new method for determining the series resistance of a solar cell from illuminated I-V measurements is presented. This technique takes advantage of the special feature of integration as a procedure to smooth data errors. The R/SUB s/ obtained represents the resistive effects globally.

  12. A Fatigue Crack Size Evaluation Method Based on Lamb Wave Simulation and Limited Experimental Data.

    PubMed

    He, Jingjing; Ran, Yunmeng; Liu, Bin; Yang, Jinsong; Guan, Xuefei

    2017-09-13

    This paper presents a systematic and general method for Lamb wave-based crack size quantification using finite element simulations and Bayesian updating. The method consists of construction of a baseline quantification model using finite element simulation data and Bayesian updating with limited Lamb wave data from target structure. The baseline model correlates two proposed damage sensitive features, namely the normalized amplitude and phase change, with the crack length through a response surface model. The two damage sensitive features are extracted from the first received S₀ mode wave package. The model parameters of the baseline model are estimated using finite element simulation data. To account for uncertainties from numerical modeling, geometry, material and manufacturing between the baseline model and the target model, Bayesian method is employed to update the baseline model with a few measurements acquired from the actual target structure. A rigorous validation is made using in-situ fatigue testing and Lamb wave data from coupon specimens and realistic lap-joint components. The effectiveness and accuracy of the proposed method is demonstrated under different loading and damage conditions.

  13. Simulation of Experimental Parameters of RC Beams by Employing the Polynomial Regression Method

    NASA Astrophysics Data System (ADS)

    Sayin, B.; Sevgen, S.; Samli, R.

    2016-07-01

    A numerical model based on the method polynomial regression is developed to simulate the mechanical behavior of reinforced concrete beams strengthened with a carbon-fiber-reinforced polymer and subjected to four-point bending. The results obtained are in good agreement with data of laboratory tests.

  14. Interactive Computing With a Programmable Calculator; Student Experimentations in Numerical Methods.

    ERIC Educational Resources Information Center

    Gerald, Curtis F.

    Programable desk calculators can provide students with personal experience in the use of numerical methods. Courses at California Polytechnic State University at San Luis Obispo use the Compucorp Model 025 Educator Experiences with it as a teaching device for solving non-linear equations and differential equations show that students can by-pass…

  15. Reducing the effects of acoustic heterogeneity with an iterative reconstruction method from experimental data in microwave induced thermoacoustic tomography

    SciTech Connect

    Wang, Jinguo; Zhao, Zhiqin Song, Jian; Chen, Guoping; Nie, Zaiping; Liu, Qing-Huo

    2015-05-15

    Purpose: An iterative reconstruction method has been previously reported by the authors of this paper. However, the iterative reconstruction method was demonstrated by solely using the numerical simulations. It is essential to apply the iterative reconstruction method to practice conditions. The objective of this work is to validate the capability of the iterative reconstruction method for reducing the effects of acoustic heterogeneity with the experimental data in microwave induced thermoacoustic tomography. Methods: Most existing reconstruction methods need to combine the ultrasonic measurement technology to quantitatively measure the velocity distribution of heterogeneity, which increases the system complexity. Different to existing reconstruction methods, the iterative reconstruction method combines time reversal mirror technique, fast marching method, and simultaneous algebraic reconstruction technique to iteratively estimate the velocity distribution of heterogeneous tissue by solely using the measured data. Then, the estimated velocity distribution is used subsequently to reconstruct the highly accurate image of microwave absorption distribution. Experiments that a target placed in an acoustic heterogeneous environment are performed to validate the iterative reconstruction method. Results: By using the estimated velocity distribution, the target in an acoustic heterogeneous environment can be reconstructed with better shape and higher image contrast than targets that are reconstructed with a homogeneous velocity distribution. Conclusions: The distortions caused by the acoustic heterogeneity can be efficiently corrected by utilizing the velocity distribution estimated by the iterative reconstruction method. The advantage of the iterative reconstruction method over the existing correction methods is that it is successful in improving the quality of the image of microwave absorption distribution without increasing the system complexity.

  16. Experimental evaluation and improvement methods for low cost transmitters in long reach PONs

    NASA Astrophysics Data System (ADS)

    Chatzi, Sotiria; Klonidis, Dimitrios; Tsekrekos, Christos P.; Lazaro, Jose A.; Prat, Josep; Tomkos, Ioannis

    2013-12-01

    An extensive experimental research of an optical access network behaviour has been realized, in the framework of studying distance enhancement of long reach passive optical networks (PONs), while maintaining low cost and high performance. The network system has been implemented with low cost transmitters - operated at low driving voltage, without the use of electrical amplification, at 10 Gb/s - and with colourless optical network units (ONUs) as receivers. Although studied for variable lengths, error-free transmission (target bit-error rate at 10-9) over 100 km reach has been achieved in several ways. The performance of extended PONs, when low cost transmitters operated at low driving voltage are utilized, is improved by the application of optical dispersion compensation and electronic equalization techniques. The chirp of the transmitter has been shown to have an important effect on the behaviour of the system because of the dispersion phenomenon. It is observed however, that the combined use of optical dispersion compensation and electronic equalization gives a reduction of 5-10 dB of the required optical signal to noise ratio (OSNR) for an error-free transmission. Moreover, it significantly reduces the heterogeneity of the system performance for several distances, yielding a predictable behaviour, while at the same time permits the use of handy, inexpensive and integrated transmitters.

  17. Confined-Pyrolysis as an Experimental Method for Hydrothermal Organic Synthesis

    NASA Technical Reports Server (NTRS)

    Leif, Roald N.; Simoneit, Bernd R. T.

    1995-01-01

    A closed pyrolysis system has been developed as a tool for studying the reactions of organic compounds under extreme hydrothermal conditions. Small high pressure stainless steel vessels in which the ratio of sediment or sample to water has been adjusted to eliminate the headspace at peak experimental conditions confines the organic components to the bulk solid matrix and eliminates the partitioning of the organic compounds away from the inorganic components during the experiment. Confined pyrolysis experiments were performed to simulate thermally driven catagenetic changes in sedimentary organic matter using a solids to water ratio of 3.4 to 1. The extent of alteration was measured by monitoring the steroid and triterpenoid biomarkers and polycyclic aromatic hydrocarbon distributions. These pyrolysis experiments duplicated the hydrothermal transformations observed in nature. Molecular probe experiments using alkadienes, alkenes and alkanes in H2O and D2O elucidated the isomerization and hydrogenation reactions of aliphatic and the competing oxidative reactions occurring under hydrothermal conditions. This confined pyrolysis technique is being applied to test experiments on organic synthesis of relevance to chemical evolution for the origin of life.

  18. Experimental methods in RIB target/ion source development and characterization

    SciTech Connect

    Welton, R.F.; Alton, G.D.; Murray, S.N.; Cui, B.

    1997-11-01

    We have developed off-line experimental techniques and apparatuses that permit direct measurement of effusive-flow delay-times and ionization efficiencies for nearly any chemically reactive element in high-temperature target/ion sources (TISs) commonly used for on-line radioactive ion beam (RIB) generation. The apparatuses include a hot Ta valve for effusive-flow delay-time measurements, a cooled molecular-injection system for determination of ionization efficiencies and a gas-flow measurement/control system for introducing very low, well-defined molecular flows into the TIS. Measurements are performed on a test-stand using molecular feed compounds containing stable complements of the radioactive nuclei of interest delivered to the TIS at flow-rates commensurate with on-line RIB generation. In this report, the general techniques are described and effusive-flow delay-times and ionization efficiency measurements are reported for fluorine in an electron-beam-plasma target/ion source (EBPTIS) developed for RIB generation and operated in both positive and negative ion extraction modes.

  19. Experimental validation of a structural damage detection method based on marginal Hilbert spectrum

    NASA Astrophysics Data System (ADS)

    Banerji, Srishti; Roy, Timir B.; Sabamehr, Ardalan; Bagchi, Ashutosh

    2017-04-01

    Structural Health Monitoring (SHM) using dynamic characteristics of structures is crucial for early damage detection. Damage detection can be performed by capturing and assessing structural responses. Instrumented structures are monitored by analyzing the responses recorded by deployed sensors in the form of signals. Signal processing is an important tool for the processing of the collected data to diagnose anomalies in structural behavior. The vibration signature of the structure varies with damage. In order to attain effective damage detection, preservation of non-linear and non-stationary features of real structural responses is important. Decomposition of the signals into Intrinsic Mode Functions (IMF) by Empirical Mode Decomposition (EMD) and application of Hilbert-Huang Transform (HHT) addresses the time-varying instantaneous properties of the structural response. The energy distribution among different vibration modes of the intact and damaged structure depicted by Marginal Hilbert Spectrum (MHS) detects location and severity of the damage. The present work investigates damage detection analytically and experimentally by employing MHS. The testing of this methodology for different damage scenarios of a frame structure resulted in its accurate damage identification. The sensitivity of Hilbert Spectral Analysis (HSA) is assessed with varying frequencies and damage locations by means of calculating Damage Indices (DI) from the Hilbert spectrum curves of the undamaged and damaged structures.

  20. Analytical methods to determine electrochemical factors in electrotaxis setups and their implications for experimental design.

    PubMed

    Schopf, Anika; Boehler, Christian; Asplund, Maria

    2016-06-01

    Direct current (DC) stimulation can be used to influence the orientation and migratory behavior of cells and results in cellular electrotaxis. Experimental work on such phenomena commonly relies on electrochemical dissolution of silver:silver-chloride (Ag:AgCl) electrodes to provide the stimulation via salt bridges. The strong ionic flow can be expected to influence the cell culture environment. In order to shed more light on which effects that must be considered, and possibly counter balanced, we here characterize a typical DC stimulation system. Silver migration speed was determined by stripping voltammetry. pH variability with stimulation was measured by ratiometric image analysis and conductivity alterations were quantified via two electrode impedance spectroscopy. It could be concluded that pH shifts towards more acidic values, in a linear manner with applied charge, after the buffering capability of the culture medium is exceeded. In contrast, the influence on conductivity was of negligible magnitude. Silver ions could enter the culture chamber at low concentrations long before a clear effect on the viability of the cultured cells could be observed. A design rule of 1cm salt bridge per C of stimulation charge transferred was however sufficient to ensure separation between cells and silver at all times.

  1. Confined-pyrolysis as an experimental method for hydrothermal organic synthesis

    NASA Astrophysics Data System (ADS)

    Leif, Roald N.; Simoneit, Bernd R. T.

    1995-10-01

    A closed pyrolysis system has been developed as a tool for studying the reactions of organic compounds under extreme hydrothermal conditions. Small high pressure stainless steel vessels in which the ratio of sediment or sample to water has been adjusted to eliminate the headspace at peak experimental conditions confines the organic components to the bulk solid matrix and eliminates the partitioning of the organic compounds away from the inorganic components during the experiment. Confined pyrolysis experiments were performed to simulate thermally driven catagenetic changes in sedimentary organic matter using a solids to water ratio of 3.4 to 1. The extent of alteration was measured by monitoring the steroid and triterpenoid biomarkers and polycyclic aromatic hydrocarbon distributions. These pyrolysis experiments duplicated the hydrothermal transformations observed in nature. Molecular probe experiments using alkadienes, alkenes and alkanes in H2O and D2O elucidated the isomerization and hydrogenation reactions of aliphatic compounds and the competing oxidative reactions occurring under hydrothermal conditions. This confined pyrolysis technique is being applied to test experiments on organic synthesis of relevance to chemical evolution for the origin of life.

  2. Evaluation of experimental methods for nitric oxide release from cardiovascular implants; bypass grafts as an exemplar.

    PubMed

    Naghavi, Noora; Seifalian, Alexander M; Hamilton, George; de Mel, Achala

    2015-12-01

    There is a great potential for nitric oxide (NO) eluting biomaterials in biomedical applications. These include the development of cardiovascular implants, wound healing products, or applications in cancer and respiratory therapy. While the potential of these materials as a therapy is becoming clearer, the real-time monitoring of NO is not easy and the success in the development of such materials depends on the accurate quantification of NO release. To emphasize on the importance of a measurement technique on the outcome of an experiment, we compared total NO released from S-nitroso-N-acetyl-d-penicillamine (SNAP) incorporated nanocomposite polymer in the form of bypass grafts under simulated physiological conditions using amperometric and chemiluminescence techniques. We found that the total amount of NO measured by the amperometric technique was 35.8% of the theoretical amount. Similarly, on measuring NO release from the bypass grafts, we demonstrated that the chemiluminesence technique detected NO at a relatively higher level. The results of this study clearly demonstrate the relative difference between analysis techniques for accurate NO detection that can be applied to distinct experimental models associated with NO-eluting cardiovascular implants. © The Author(s), 2015.

  3. Confined-Pyrolysis as an Experimental Method for Hydrothermal Organic Synthesis

    NASA Technical Reports Server (NTRS)

    Leif, Roald N.; Simoneit, Bernd R. T.

    1995-01-01

    A closed pyrolysis system has been developed as a tool for studying the reactions of organic compounds under extreme hydrothermal conditions. Small high pressure stainless steel vessels in which the ratio of sediment or sample to water has been adjusted to eliminate the headspace at peak experimental conditions confines the organic components to the bulk solid matrix and eliminates the partitioning of the organic compounds away from the inorganic components during the experiment. Confined pyrolysis experiments were performed to simulate thermally driven catagenetic changes in sedimentary organic matter using a solids to water ratio of 3.4 to 1. The extent of alteration was measured by monitoring the steroid and triterpenoid biomarkers and polycyclic aromatic hydrocarbon distributions. These pyrolysis experiments duplicated the hydrothermal transformations observed in nature. Molecular probe experiments using alkadienes, alkenes and alkanes in H2O and D2O elucidated the isomerization and hydrogenation reactions of aliphatic and the competing oxidative reactions occurring under hydrothermal conditions. This confined pyrolysis technique is being applied to test experiments on organic synthesis of relevance to chemical evolution for the origin of life.

  4. Publications on experimental physical methods to investigate ultra high dilutions--an assessment on quality.

    PubMed

    Schulte, Jurgen

    2015-10-01

    Our first evaluation of fundamental research into the physics and physiology of Ultra High Dilution (UHD) was conducted in 1994. Since then, in 2003, Becker-Witt et al. conducted a more systematic evaluation of the literature and established the Score for Assessment of Physical Experiments on Homeopathy (SAPEH). While this evaluation focused on experimental methodologies, Stock-Schröer et al., in 2009, formulated a detailed guideline for authors on Reporting Experiments in Homeopathic Basic research (REHBaR) to promote a high standard in research as well as in its communication in scientific literature. In this paper, we evaluate publications on basic research into the physics of UHD since the decade following the presentation of the SAPEH score (2004-2014), and present the state of progress in this field. Fundamental research into the physics of UHD has been reported at a steady rate over the past 60 years. Reported research of high quality as per SAPEH scoring appears to be still the exception rather than standard. Considering the importance of a fundamental understanding of what makes a UHD preparation, results of this study suggest that it may be beneficial to this field of fundamental research if grant challenges are approached in strategic way similar to other grant challenges in science. Copyright © 2015 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

  5. Experimental Methods to Observe Asymmetric Instability of Intermediate-Reduced-Volume Vesicles in Extensional Flow

    NASA Astrophysics Data System (ADS)

    Dahl, Joanna; Narsimhan, Vivek; Gouveia, Bernardo; Kumar, Sanjay; Shaqfeh, Eric; Muller, Susan

    2014-11-01

    Vesicles provide an attractive model system to understand the deformation of living cells in response to mechanical forces. These enclosed lipid bilayer membranes are suitable for complementary theoretical and experimental analysis. A recent study (Narsimhan et al., J. Fluid Mech. 750, 144 (2014)) predicted that intermediate-aspect-ratio vesicles break up asymmetrically in extensional flow. Upon infinitesimal perturbation to its shape, the vesicle stretches into an asymmetric dumbbell. In this work, we present preliminary results from cross-slot microfluidic experiments observing this instability. The onset of breakup depends on two non-dimensional parameters: reduced volume (vesicle asphericity) and capillary number (ratio of viscous to bending forces). We will present strategies for accurately measuring these quantities in order to plot a stability diagram. Specifically, we will describe our synthesis of floppy, intermediate-reduced-volume vesicles and our measurement of their bending moduli by analyzing membrane thermal fluctuations. We will discuss coupling particle-image velocimetry (PIV) with cross-slot trapping of vesicles to ensure that breakup occurs at the stagnation point. A preliminary phase diagram for asymmetric breakup will be reported.

  6. A Dynamic Calibration Method for Experimental and Analytical Hub Load Comparison

    NASA Technical Reports Server (NTRS)

    Kreshock, Andrew R.; Thornburgh, Robert P.; Wilbur, Matthew L.

    2017-01-01

    This paper presents the results from an ongoing effort to produce improved correlation between analytical hub force and moment prediction and those measured during wind-tunnel testing on the Aeroelastic Rotor Experimental System (ARES), a conventional rotor testbed commonly used at the Langley Transonic Dynamics Tunnel (TDT). A frequency-dependent transformation between loads at the rotor hub and outputs of the testbed balance is produced from frequency response functions measured during vibration testing of the system. The resulting transformation is used as a dynamic calibration of the balance to transform hub loads predicted by comprehensive analysis into predicted balance outputs. In addition to detailing the transformation process, this paper also presents a set of wind-tunnel test cases, with comparisons between the measured balance outputs and transformed predictions from the comprehensive analysis code CAMRAD II. The modal response of the testbed is discussed and compared to a detailed finite-element model. Results reveal that the modal response of the testbed exhibits a number of characteristics that make accurate dynamic balance predictions challenging, even with the use of the balance transformation.

  7. A novel experimental method for the local mechanical testing of human coronal dentin.

    PubMed

    Ziskind, Daniel; Fleischer, Sharly; Zhang, Kaiyin; Cohen, Sidney R; Daniel Wagner, H

    2010-02-01

    The small volume of human dentin available for sample preparation and the local variations in its microstructure present a real challenge in the determination of their mechanical properties. The main purpose of the present study was to develop a new procedure for the preparation and mechanical testing of small-scale specimens of biomaterials such as dentin, so as to probe local mechanical properties as a function of microstructure. Ultra short laser pulses were used to mill a block of dentin into an array of 16 microm size dentin pillars. These could then be individually tested in compression with an instrumented nanoindenter fitted with a 30 microm wide flat punch. The laser-based pillar preparation procedure proved effective and reliable. Data was produced for the mechanical properties of a first set of dry dentin micro-pillars. This novel experimental approach enables the preparation and compression of micron-scale samples with well-defined microstructure. For dentin, this means samples containing a relatively small number of well-defined parallel tubules, with a distinct orientation relative to the applied load. The ability to isolate the separate effects of microstructural parameters on the mechanical properties is of major significance for future substantiation of theoretical models. Copyright 2009 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  8. A new method for studying microaerobic fermentations; 2: An experimental investigation of xylose fermentation

    SciTech Connect

    Franzen, C.J.; Liden, G.; Niklasson, C. . Dept. of Chemical Reaction)

    1994-08-05

    A new experimental technique, called oxygen programmed fermentation (OPF), was used to study microbial cultures of the yeasts Pichia stipitis and Candida utilis growing on xylose as carbon and energy source. In the oxygen programmed fermentation, the inlet oxygen mole fraction was continuously changed to scan through a wide range of oxygen uptake rates in a continuous culture. The largest ethanol yields and productivities for P. stipitis were found at oxygen transfer rates below 1.5 mmol L[sup [minus]1] h[sup [minus]1]. It was found that the ratio between the culture fluorescence and near-IR absorbance increased at oxygen transfer rates lower than 1.5 mmol L[sup [minus]1] h[sup [minus]1]. Small amounts of ethanol were produced also by C. utilis when the oxygen transfer rate was between 0 and 3 mmol L[sup [minus]1] h[sup [minus]1]. It is suggested that OPF will form a nice complement to ordinary, microaerobic chemostat experiments, by making the identification of interesting regions of oxygen transfer rates possible in an efficient and time-saving initial experiment.

  9. Confined-pyrolysis as an experimental method for hydrothermal organic synthesis.

    PubMed

    Leif, R N; Simoneit, B R

    1995-10-01

    A closed pyrolysis system has been developed as a tool for studying the reactions of organic compounds under extreme hydrothermal conditions. Small high pressure stainless steel vessels in which the ratio of sediment or sample to water has been adjusted to eliminate the headspace at peak experimental conditions confines the organic components to the bulk solid matrix and eliminates the partitioning of the organic compounds away from the inorganic components during the experiment. Confined pyrolysis experiments were performed to simulate thermally driven catagenetic changes in sedimentary organic matter using a solids to water ratio of 3.4 to 1. The extent of alteration was measured by monitoring the steroid and triterpenoid biomarkers and polycyclic aromatic hydrocarbon distributions. These pyrolysis experiments duplicated the hydrothermal transformations observed in nature. Molecular probe experiments using alkadienes, alkenes and alkanes in H2O and D2O elucidated the isomerization and hydrogenation reactions of aliphatic compounds and competing oxidative reactions occurring under hydrothermal conditions. This confined pyrolysis technique is being applied to test experiments on organic synthesis of relevance to chemical evolution for the origin of life.

  10. Fundamental comparison of time-domain experimental modal analysis methods based on high- and first-order matrix models

    NASA Astrophysics Data System (ADS)

    Hu, Sau-Lon James; Yang, Wen-Long; Liu, Fu-Shun; Li, Hua-Jun

    2014-12-01

    All time-domain methods for experimental modal analysis (EMA) begin with a mathematical model. Based on either a high-order matrix polynomial model or a first-order state-space model, this paper emphasizes the comparison of numerical conditioning and stability, as well as the modal parameter estimation, among EMA methods. Numerical conditioning pertains to the perturbation behavior of a mathematical problem (model) itself and stability pertains to the perturbation behavior of an algorithm used to solve that problem on a computer. As various EMA methods are modeled differently with distinct solution algorithms, implementing these methods would have different conditioning and stability. In this paper, both deterministic and stochastic EMA methods are covered. Three different scenarios for the response signal are considered: (1) clean response from impulse loading, (2) noisy response from impulse loading, and (3) noisy response from ambient noise excitation. Comparing the numerical conditioning of various EMA methods, this paper theoretically illustrates that methods based on first-order state-space models are more likely to be well-conditioned (with a smaller conditioning number) than those based on high-order polynomial models. Furthermore, the numerical observation of a case study for a 6 degree-of-freedom system also suggests that first-order state-space model methods are more robust and accurate for the estimation of modal frequency and damping.

  11. Electromagnetic flowmetry--an experimental method for continuous blood flow measurement using a new island flap model.

    PubMed

    Banis, J C; Schwartz, K S; Acland, R D

    1980-10-01

    We describe a reliable experimental method for direct, continuous measurement of the rate of blood flow in an island skin flap, using an electromagnetic flowmeter applied to the artery of the flap. The canine saphenous island flap model, developed as part of this study, is a large (11 x 14 cm) island flap, based solely on the saphenous artery (2 mm in diameter). We describe the anatomy of the flap and the method of raising it. Electromagnetic flowmetry is the only method of blood flow determination that provides immediate, continuous, and quantitative measurement of flow. We describe the principles and pitfalls of the electromagnetic flowmeter and the numerous rules of practice that must be observed to obtain consistent results. A validation study was carried out, in which we simultaneously measured arterial inflow with the flowmeter and venous outflow from the flap using direct collection. This study was based on the assumption that at any point in time the arterial and venous rate of flow were equal. We present the results of the study, which show an extremely close linear relationship between the measured and actual rates of flow. We intend to use this experimental method to study the factors that affect the rate of blood flow in free skin flap transfer.

  12. The experimental verification of a streamline curvature numerical analysis method applied to the flow through an axial flow fan

    NASA Technical Reports Server (NTRS)

    Pierzga, M. J.

    1981-01-01

    The experimental verification of an inviscid, incompressible through-flow analysis method is presented. The primary component of this method is an axisymmetric streamline curvature technique which is used to compute the hub-to-tip flow field of a given turbomachine. To analyze the flow field in the blade-to-blade plane of the machine, the potential flow solution of an infinite cascade of airfoils is also computed using a source model technique. To verify the accuracy of such an analysis method an extensive experimental verification investigation was conducted using an axial flow research fan. Detailed surveys of the blade-free regions of the machine along with intra-blade surveys using rotating pressure sensing probes and blade surface static pressure taps provide a one-to-one relationship between measured and predicted data. The results of this investigation indicate the ability of this inviscid analysis method to predict the design flow field of the axial flow fan test rotor to within a few percent of the measured values.

  13. Can migraine aura be provoked experimentally? A systematic review of potential methods for the provocation of migraine aura.

    PubMed

    Lindblad, Marianne; Hougaard, Anders; Amin, Faisal Mohammad; Ashina, Messoud

    2017-01-01

    Background The nature of the migraine aura and its role in migraine pathophysiology is incompletely understood. In particular, the mechanisms underlying aura initiation and the causal relation between aura and headache are unknown. The scientific investigation of aura in patients is only possible if aura can be triggered. This paper reviews potential methods for the experimental provocation of migraine aura. Methods We systematically searched PubMed for studies of experimental migraine provocation, including case reports of patients with aura and reports of the occurrence of aura following exposure to any kind of suspected trigger. Results We identified 21 provocation studies, using 13 different prospective provocation methods, and 34 case reports. In the prospective studies, aura were reported following the administration of intravenous and sublingual glyceryl trinitrate, visual stimulation, physical activity, calcitonin gene-related peptide infusion, chocolate ingestion, and the intravenous injection of insulin. In addition, carotid artery puncture has consistently been reported as a trigger of aura. Conclusions No safe and efficient method for aura provocation exists at present, but several approaches could prove useful for this purpose.

  14. The experimental verification of a streamline curvature numerical analysis method applied to the flow through an axial flow fan

    NASA Technical Reports Server (NTRS)

    Pierzga, M. J.

    1981-01-01

    The experimental verification of an inviscid, incompressible through-flow analysis method is presented. The primary component of this method is an axisymmetric streamline curvature technique which is used to compute the hub-to-tip flow field of a given turbomachine. To analyze the flow field in the blade-to-blade plane of the machine, the potential flow solution of an infinite cascade of airfoils is also computed using a source model technique. To verify the accuracy of such an analysis method an extensive experimental verification investigation was conducted using an axial flow research fan. Detailed surveys of the blade-free regions of the machine along with intra-blade surveys using rotating pressure sensing probes and blade surface static pressure taps provide a one-to-one relationship between measured and predicted data. The results of this investigation indicate the ability of this inviscid analysis method to predict the design flow field of the axial flow fan test rotor to within a few percent of the measured values.

  15. Experimental Methods to Evaluate Science Utility Relative to the Decadal Survey

    NASA Technical Reports Server (NTRS)

    Widergren, Cynthia

    2012-01-01

    The driving factor for competed missions is the science that it plans on performing once it has reached its target body. These science goals are derived from the science recommended by the most current Decadal Survey. This work focuses on science goals in previous Venus mission proposals with respect to the 2013 Decadal Survey. By looking at how the goals compare to the survey and how much confidence NASA has in the mission's ability to accomplish these goals, a method was created to assess the science return utility of each mission. This method can be used as a tool for future Venus mission formulation and serves as a starting point for future development of create science utility assessment tools.

  16. Methods of Experimental Investigation of Cavitation in a Convergent - Divergent Nozzle of Rectangular Cross Section

    NASA Astrophysics Data System (ADS)

    Jablonská, Jana; Kozubková, Milada; Himr, Daniel; Weisz, Michal

    2016-08-01

    Cavitation is a phenomenon with both positive and negative effects and with dynamic manifestations in hydraulic, food, chemical and other machinery. This article deals with the detection and dynamic behavior of cavitation clouds in water flows through a rectangular cross-section convergent-divergent nozzle. Cavitation was measured by methods applicable in engineering practice. Pressure, flow rate, noise, vibration, and amount of air dissolved in the liquid were measured and cavitation region was recorded with a high-speed camera. Evaluation of acquired images in connection with measured pressure pulsations and mechanical vibrations was performed with the use of the FFT method. In certain cases, dimensionless parameters were used to generalize the measurements. The results will be used to specify multiphase mathematical cavitation model parameters.

  17. Thermochemistry of dihalogen-substituted benzenes: data evaluation using experimental and quantum chemical methods.

    PubMed

    Verevkin, Sergey P; Emel'yanenko, Vladimir N; Varfolomeev, Mikhail A; Solomonov, Boris N; Zherikova, Kseniya V; Melkhanova, Svetlana V

    2014-12-11

    Temperature dependence of vapor pressures for 12 dihalogen-substituted benzenes (halogen = F, Cl, Br, I) was studied by the transpiration method, and molar vaporization or sublimation enthalpies were derived. These data together with results available in the literature were collected and checked for internal consistency using structure-property correlations. Gas-phase enthalpies of formation of dihalogen-substituted benzenes were calculated by using quantum-chemical methods. Evaluated vaporization enthalpies in combination with gas-phase enthalpies of formation were used for estimation liquid-phase enthalpies of formation of dihalogen-substituted benzenes. Pairwise interactions of halogens on the benzene ring were derived and used for development of simple group additivity procedures for estimation of vaporization enthalpies, gas-phase, and liquid-phase enthalpies of formation of dihalogen-substituted benzenes.

  18. Experimental design and multiple response optimization. Using the desirability function in analytical methods development.

    PubMed

    Candioti, Luciana Vera; De Zan, María M; Cámara, María S; Goicoechea, Héctor C

    2014-06-01

    A review about the application of response surface methodology (RSM) when several responses have to be simultaneously optimized in the field of analytical methods development is presented. Several critical issues like response transformation, multiple response optimization and modeling with least squares and artificial neural networks are discussed. Most recent analytical applications are presented in the context of analytLaboratorio de Control de Calidad de Medicamentos (LCCM), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, C.C. 242, S3000ZAA Santa Fe, ArgentinaLaboratorio de Control de Calidad de Medicamentos (LCCM), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, C.C. 242, S3000ZAA Santa Fe, Argentinaical methods development, especially in multiple response optimization procedures using the desirability function.

  19. Advanced experimental applications for x-ray transmission gratings spectroscopy using a novel grating fabrication method

    NASA Astrophysics Data System (ADS)

    Hurvitz, G.; Ehrlich, Y.; Strum, G.; Shpilman, Z.; Levy, I.; Fraenkel, M.

    2012-08-01

    A novel fabrication method for soft x-ray transmission grating and other optical elements is presented. The method uses focused-ion-beam technology to fabricate high-quality free standing grating bars on transmission electron microscopy grids. High quality transmission gratings are obtained with superb accuracy and versatility. Using these gratings and back-illuminated CCD camera, absolutely calibrated x-ray spectra can be acquired for soft x-ray source diagnostics in the 100-3000 eV spectral range. Double grating combinations of identical or different parameters are easily fabricated, allowing advanced one-shot application of transmission grating spectroscopy. These applications include spectroscopy with different spectral resolutions, bandwidths, dynamic ranges, and may serve for identification of high-order contribution, and spectral calibrations of various x-ray optical elements.

  20. Study on energy saving of subway station based on orthogonal experimental method

    NASA Astrophysics Data System (ADS)

    Guo, Lei

    2017-05-01

    With the characteristics of quick, efficient and large amount transport, the subway has become an important way to solve urban traffic congestion. As the subway environment will follow the change of external environment factors such as temperature and load of personnel changes, three-dimensional numerical simulations study is conducted by using CFD software for air distribution of subway platform. The influence of different loads (the supply air temperature and velocity of air condition, personnel load, heat flux of the wall) on the subway platform flow field are also analysed. The orthogonal experiment method is applied to the numerical simulation analysis for human comfort under different parameters. Based on those results, the functional relationship between human comfort and the boundary conditions of the platform is produced by multiple linear regression fitting method, the order of major boundary conditions which affect human comfort is obtained. The above study provides a theoretical basis for the final energy-saving strategies.