Method For Measurement Of Density Research Articles

Use of Pulsed Radiography for Investigation of Equations of State of Substances at Megabar Pressures

AbstractA method of density measurement for substances that are isentropically compressed up to megabar pressures is described in the paper. Measurement results for condensed hydrogen isotopes and aluminum are presented. These results, afterwards, are used for construction of hydrogen isotopes “cold” isentropes. Experimental x‐ray images of the facilities with the hydrogen isotopes, compressed up to several megabars are presented in the paper (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Thickness scan of metallic layer by photon induced X-ray emission

Simple and efficient method for precise surface density measurement in the range of about few mg/cm 2 for layers consisting of heavy elements, based on photon induced X-ray emission has been developed. The method has been applied to analyze Mott-scattering targets used in the measurement of the transverse electron polarization of electrons emitted in the neutron beta decay. The achieved relative accuracy is 1%. The absolute calibration accuracy of 2.3% was achieved with the atomic absorption spectroscopy.

Interface Trap Density Metrology of State-of-the-Art Undoped Si n-FinFETs

The presence of interface states at the MOS interface is a well-known cause of device degradation. This is particularly true for ultrascaled FinFET geometries where the presence of a few traps can strongly influence the device behavior. Typical methods for interface trap density (D_it) measurements are not performed on ultimate devices but on custom-designed structures. We present the first set of methods that allow direct estimation of D_it in state-of-the-art FinFETs, addressing a critical industry need.

Density measurement algorithm for freeway segment using two point detectors

AbstractDensity is the most important congestion indicator among fundamental traffic flow variables—flow, speed, and density. Measuring density by aerial monitoring, although accurate, cannot be widely used because of its cost and dependency on weather. The conventional method, estimating density based on the relationship between traffic flow and speed as measured by a point detector, does not yield an accurate density value, because the flow is not homogeneous. A new and advanced density measurement method, which is based on the in‐out counting method, is proposed. This method uses average density instead of instantaneous density. By using two point detectors, this method can capture considerable variation in density and is accurate for single and multilane freeway segments. Establishing the number of floating vehicles necessary to obtain a fair approximation of the true density is for future research. Copyright © 2011 John Wiley & Sons, Ltd.

Quantitative Microplasma Electron Number Density Measurement by Coherent Microwave Rayleigh Scattering

In this paper, a method for quantitative measurement of electron number density in a microplasma by coherent microwave Rayleigh scattering is described. Coherent microwave Rayleigh scattering reaches its maximum when the microwave frequency is at its resonance frequency. The resonance frequency depends on the electron number density in the microplasma and the electron-neutral and Coulomb collisional frequencies. When a subnanosecond microwave pulse illuminates the microplasma, the average electron number density can be measured from the frequency analysis of microwave scattering. The technique will be able to quantitatively measure subnanosecond-resolved electron number density evolution in the microplasma.

A Study for Implementation of Density Measurement Equipment for Asphalt Pavement based on the electromagnetic capacitance

In this paper we developed density measurement equipment for Asphalt Pavement based on the electromagnetic capacitance. This kind of Non-Nuclear Density Gauges technology and products is used or studied in USA, Finland, Sweden as standardization of authorized method for pavement density measurement. Effective permitivity of pavement asphalt is characterized in electromagnetic capacitance by the asphalt material, mixed ratio, and harden grade of pavement asphalt. We can get a density value of asphalt by replacing value of electromagnetic capacitance with standard density value and characteristic transformation curve. We are conformed that measurement data according to temperature, humidity, and real field asphalt of our density measurement equipment can be a precise value.

The Comparative Method for Apparent Density Measurement as a Means of Fine Carbonaceous and Inorganic Porous Material Characterization by the Determination of Shape Coefficient

These investigations are a part of work whose aim is an elaboration of a characterization method for porous fine powders with use of densimetric measurements. Especially, attention to methods of shape coefficient determination was given in this work because many other investigations pointed out that knowledge of this parameter is necessary for such studies. Shape coefficient values were determined with the use of Powers's method (K), the quantitative method (1/L), and the new comparative method (1/k). While densimetric measurements in the characterization of solids are a standard, the comparative method of apparent density determination is applied for the calculation of shape coefficients (1/k). The shape coefficient (1/k) characterizes not a single element of the fine solid but a collection of particles in the bed. The coefficient (1/k) represents the out-of-roundness degree of packed grains in relation to a bed of spheres with the same size distribution as the investigated material.

Development of CO2 laser dispersion interferometer with photoelastic modulator

A dispersion interferometer is one of the promising methods of the electron density measurement on large and high density fusion devices. This paper describes development of a CO(2) laser dispersion interferometer with a photoelastic modulator for phase modulation. In order to make the dispersion interferometer free from variations of the detected intensity, a new phase extraction method is introduced: The phase shift is evaluated from a ratio of amplitudes of the fundamental and the second harmonics of the phase modulation frequency in the detected interference signal. The proof-of-principle experiments demonstrate the feasibility of this method.

Apparent motion photometry: evaluation and reliability of a novel method for the measurement of macular pigment

Background/aimsMacular pigment is thought to protect the macula against exposure to light and oxidative stress, both of which may play a role in the development of age-related macular degeneration. The...

Weight Function Control of Moving Least-Squares Interpolants: Application to Axisymmetric Shielding Current Analysis in HTS

The modified basis functions of element-free Galerkin (EFG) method generated by weight function control of moving least-squares interpolants for an axisymmetric problem are investigated. In the axisymmetric problem, a physical quantity of rotating angle direction on the symmetry axis should be zero. By using standard EFG, however, the values on symmetric axis are non zero because the axisymmetric is not considered in basis function. In order to clear up the above problem, the modified basis function of EFG is proposed. The numerical simulation of shielding current density in axisymmetric high-temperature superconductor is adopted for practical applications of modified axisymmetric EFG. The results of computations show that the shielding current density on symmetric axis vanish in both cases. In addition, the experimental critical current density measurement method is reproduced numerically by using the numerical code.

REAL-TIME MEASUREMENT OF ICE CONCENTRATIONS IN ICE SLURRY FLOW

An experimental study was performed to measure the ice concentration of an ice slurry pipe flow in real time. In the present work, we suggest a refractive index measurement method and compare it to freezing point and density measurement methods. To measure the refractive index of the solution, ice particles in the ice slurry should be completely removed and a hydro-cyclone was used in this study instead of a mesh. The results from the measurement method by the refractive index coincided with those by the density within a ±5% error range when the real-time solution density was used. Even though the density measurement method showed good resolution, the results using the initial density of the solution were more than 10% in error compared to those using the real-time density. And the density measurement method has an error range 1.5 times greater than the refractive index measurement method.

The effects of raloxifene on mammographic breast density

Breast density is an independent risk factor for the development of invasive breast cancer (BC). It has been hypothesized that because raloxifene (RLX) has been shown to reduce BC risk, its use will result in reduced breast density. This article provides a review of seven clinical studies that examined the effects of RLX on breast density. Overall, RLX did not increase or decrease mammographic breast density. This article provides a review of the various methods used to determine breast density in these RLX studies and offers a potential explanation as to why the studies failed to show an effect on mammographic density. Presently, no clinical recommendations can be made with regard to RLX and its effects on breast density. To determine the effect of RLX on breast density, larger studies need to be conducted in postmenopausal women with high breast density at baseline who are at high risk for BC, with a standardized method of breast density measurement.

Plasma density measurements by phase resolved cutoff

A method for precise measurement of absolute electron density in the plasma using plasma frequency is proposed. The phase difference between two antennas (radiating and detecting antennas) and its slow time modulation was used, instead of the transmittance used in previous cutoff probe, and a remarkable result is observed. This method can determine the absolute electron density precisely: It is not only in a good agreement with the previous method very closely but also is able to find the cutoff point clearly even in difficult conditions where there are ambiguities to determine the cutoff point with previous method.

Characterisation of a toroidal plasma in a magnetic field by the floating double probe technique for hydrogen

In the present work, the floating double probe technique was used to determine the plasma parameters by using the equivalent resistance method [1,2,3,4,5] for hydrogen in toroidal discharge. Measurements were done for transverse and longitudinal positions of the probes to the axial toroidal magnetic field. The experiment was carried out in a 13.56 MHz inductively coupled radio frequency plasma discharge at different pressures of 0.07 torr to 0.20 torr and magnetic fields of 0G to 75G and observed the differences of plasma temperature and particle number density on the discharge axis of the torus. It is also observed that the plasma temperature decreases where as the plasma radial density increases for axial positions but for transverse positions of the probes, the plasma temperature increases and the radial density decreases with the magnetic field and changes with pressure also. The results were compared with nitrogen and argon as well as with direct current glow discharge plasmas with identical input magnetic field [6]. The validity of the probe method for measurement of plasma temperature and density in a toroidal discharge has been discussed.

Screen-Film Mammographic Density and Breast Cancer Risk: A Comparison of the Volumetric Standard Mammogram Form and the Interactive Threshold Measurement Methods

Mammographic density is a strong risk factor for breast cancer, usually measured by an area-based threshold method that dichotomizes the breast area on a mammogram into dense and nondense regions. Volumetric methods of breast density measurement, such as the fully automated standard mammogram form (SMF) method that estimates the volume of dense and total breast tissue, may provide a more accurate density measurement and improve risk prediction. In 2000-2003, a case-control study was conducted of 367 newly confirmed breast cancer cases and 661 age-matched breast cancer-free controls who underwent screen-film mammography at several centers in Toronto, Canada. Conditional logistic regression was used to estimate odds ratios of breast cancer associated with categories of mammographic density, measured with both the threshold and the SMF (version 2.2beta) methods, adjusting for breast cancer risk factors. Median percent density was higher in cases than in controls for the threshold method (31% versus 27%) but not for the SMF method. Higher correlations were observed between SMF and threshold measurements for breast volume/area (Spearman correlation coefficient = 0.95) than for percent density (0.68) or for absolute density (0.36). After adjustment for breast cancer risk factors, odds ratios of breast cancer in the highest compared with the lowest quintile of percent density were 2.19 (95% confidence interval, 1.28-3.72; P(t) <0.01) for the threshold method and 1.27 (95% confidence interval, 0.79-2.04; Pt = 0.32) for the SMF method. Threshold percent density is a stronger predictor of breast cancer risk than the SMF version 2.2beta method in digitized images.

A new and facile method for measurement of apparent density of monodisperse polymer beads

The apparent density, an intrinsic physical property of polymer beads, plays an important role in the application of beads in micro-total analysis systems and separation. Here we have developed a new, facile and milligram-scale method to describe the motion of beads in aqueous solution and further detect the apparent density of beads. The motion of beads in solutions is determined by the viscosity of solutions and the density difference between beads and solutions. In this study, using various glycerol aqueous solutions with certain viscosities and densities, the motion time (i.e. floating or sedimentation time) of hybrid polymer beads was experimentally measured and theoretically deduced, and consequently, the apparent density of monodisperse beads can be quickly and easily calculated. The results indicated that the present method provided a more precise way to predict the movement of hybrid beads in aqueous solution compared with the approach for commercial use. This new method can be potentially employed in flow cytometry, suspension stability, and particle analysis systems.

Analysis of Measurement Method for Critical Current Density by Using Permanent Magnet

The permanent-magnet method for measuring critical current density in high-temperature superconducting thin films is numerically and experimentally investigated. Numerical results show that the critical current density is approximately proportional to the maximum repulsive force. Furthermore, the maximum repulsive force increases as the value of diameter of permanent magnet increases. This tendency is also observed in the experimental investigation. Finally, spatial distributions of the shielding current density are experimentally reproduced by the system.

Density Change of an Oxidized Nuclear Graphite by Acoustic Microscopy and Image Processing

The strong correlation between the density and the physical and mechanical properties of graphite suggests that the method of nondestructive density evaluation could be developed into a characterization technique of great value for the overall improvement of the safety of graphite moderator reactors. In this study, the oxidation-induced density changes in nuclear graphite for very high temperature reactor were determined by a conventional destructive bulk density measurement method (BM) and by a new nondestructive method based on acoustic microscopy and image processing (AM). The results were compared in order to validate the applicability of the latter method. For a direct comparison of the results from both measurements, two specimens were prepared from a cylindrical graphite sample (1 in. diameter and 1 in. height, oxidized to 10% weight loss at 973 K in air for 5 h). The specimens were used for characterization by BM and AM methods, respectively. The results show that, even with a large standard deviation of the AM, the density changing trend from both methods appeared the same. The present observation may be attributed to the fact that AM images reflect characteristic density changes of the graphite sample through the acoustic impedance changes. This study demonstrates the possibility of using AM as a nondestructive technique for the evaluation of density changes in graphite when a database is prepared through a systematic series of experiments.

Axisymmetric Simulation of Inductive Measurement Method for Critical Current Density in Bulk HTS: Relation Between Third Harmonic Voltage and Coil Current

The inductive measurement method for the critical current density in a bulk high-temperature superconductor (HTS) has been investigated by using the axisymmetric simulation. In the method, an ac current <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> sin 2pi <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ft</i> is applied in a small coil placed just above a bulk HTS and, simultaneously, the third harmonic voltage <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> sin(6pi <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ft</i> + thetas <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) is measured. In order to simulate the inductive method, <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> - <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> curves are determined by use of the simulation and, subsequently, the critical current density is estimated. The results of computations show that the accuracy of the inductive method is influenced by neither the frequency nor the applied dc magnetic field.

Analysis of Measurement Method for Critical Current Density by Using Permanent Magnet

The Permanent Magnet method for measuring critical current density in high-temperature superconducting thin film is numerically and experimentally investigated. Numerical results show that the critical current density is approximately proportional to the maximum repulsive force. Furthermore, the maximum repulsive force increases as the value of diameter of permanent magnet increases. These tendency is also observed in the experimental investigation. Finally, the spatial distributions of the shielding current density are reproduced by the system experimentally.