Radiation Intensity Profile Research Articles

New algorithm of measuring gravitational wave radiation from rotating binary system

In order to investigate the gravitational wave (GW) radiation, without resorting to the traceless transverse gauge approach to the GW formalism of the linearized general relativity, we formulate the so-called modified linearized general relativity (MLGR). As an application of the MLGR, we construct a novel paradigm of measuring the GW radiation from a binary system of compact objects, to theoretically interpret its phenomenology. To accomplish this, we formulate the mass scalar and mass vector potentials for the merging binary compact objects, from which we construct the mass magnetic field in addition to the mass electric one which also includes the mass vector potential effect. Next, defining the mass Poyinting vector in terms of the mass electric and mass magnetic fields in the MLGR, we find the GW radiation intensity profile possessing a prolate ellipsoid geometry due to the merging binary compact objects source. At a given radial distance from the binary compact objects, the GW radiation intensity on the revolution axis of the binary compact objects is shown to be twice that on the equatorial plane. Moreover, we explicitly obtain the total radiation power of the GW, which has the same characteristic as that of the electromagnetic wave in the rotating charge electric dipole moment. We also find that, in no distorting limit of the merging binary compact objects, the compact objects in the MLGR do not yield the total GW radiation power, consistent with the result of the traceless transverse gauge algorithm in the linearized general relativity.

Spatial distribution of radiation emitted by pulsed surface dielectric barrier discharge in air

The dynamics of radiation intensity at 337 nm emitted by the surface dielectric barrier discharge driven by 50 ns duration and 8 kV amplitude voltage pulse of both polarities has been analyzed experimentally and numerically. The calculations were performed in a 2D approach for experimental conditions to check the existing numerical models and understand what processes manage the discharge length and the spatial distribution of the discharge radiation intensity. Experimentally measured and numerically simulated profiles of radiation intensity along the discharge length notably differ from each other and the performed modification of the discharge physical model does not essentially change this difference. Radiation intensity from the discharge channel has been shown to be extremely sensitive primarily to the value of reduced electric field. We suppose that the discrepancy between experiment and numerical simulation could be due to 2D instead of 3D simulation and corresponding incorrect estimation of electric field distribution along the discharge channel. The numerical simulation of discharge length is in good agreement with experiment for the discharge stroke at the leading front of the voltage pulse and gives few times less values for the backward discharge at the trailing edge of the voltage pulse.

EMSIW-Based Compact High Gain Wide Full Space Scanning LWA With Improved Broadside Radiation Profile

A novel compact high gain eighth-mode substrate-integrated-waveguide (EMSIW)-based double asymmetry (DA) composite right-/left-handed (CRLH) leaky-wave antenna with larger degrees of freedom to control the efficiency is proposed and investigated. The proposed tilted DA radiating EMSIW incorporated with radiating interdigital capacitive (IDC) slots enables the unit cell to hold CRLH property with improved compactness and gain. The DA not only provides increased efficiency at broadside frequency than off-broadside but also offers more degrees of freedom to independently control the series and shunt resonators of the proposed geometry. Dispersion analysis is done by full-wave simulation and validated by theoretical analysis through predicted equivalent circuit model for achieving the balance condition of the unit cell which facilitates the complete elimination of open-stopband. Due to the systematic placement of interdigital slots on radiating EMSIW unit cell, the radiation intensity profile is significantly enhanced, which leads to higher directivity and notably enhanced gain (17.96 dBi). The proposed prototype is 5λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> long having ten unit cells. The beam scanning range of the proposed antenna is 107° within 9-13.5 GHz, with the maximum broadside radiation efficiency of ~96%.

A method for measurement of spatially resolved radiation intensity and radiative fraction of laminar flames of gaseous and solid fuels

This work introduces a new method for determination of spatially resolved radiation intensity and radiative fraction for axisymmetric laminar diffusion flames by using a modified DSL-R camera employed to collect monochromatic, 900 nm, images and a Schmidt-Boelter heat flux gauge. A novel instrument, Milligram-scale Flame Calorimeter, is employed to supply the flame with either gaseous fuel or solid fuel pyrolyzate and measure the total heat release rate associated with the combustion process. The high spatial resolution provided by the images of the camera allows for a multi-emitter treatment of the 20–60 mm tall flames. The flames’ shapes and monochromatic radiation intensity profiles are extracted from the images. Using the radiation transport equations formulated for the system’s specific geometry, the monochromatic radiation intensities are related to the total heat flux gauge readings collected at several distances from the base of the flame. Subsequently, spatially resolved total radiation intensity data are obtained. Integration of this intensity over the flame surface yields the radiation heat release rate, of which the ratio to the total heat release rate yields the radiative fraction. In this work, methane, propane and acetylene flames have been studied to validate this methodology (covering a wide range of sooting conditions), while polyethylene-fueled flames above and below the smoke point have been analyzed to demonstrate the method’s applicability to solid fuels. The results show that the method produces values that are consistent with previous studies, particularly when the assumptions of the previous studies are replicated. Additionally, the data indicate that for flame heights that are all below (or all above) the smoke point, the value of the maximum total radiation intensity does not depend on the total heat release rate. This behavior of the maximum radiation intensity suggests that said parameter is a good candidate to correlate with the radiative properties of turbulent flames.

Radiation intensity profiles at various stages of apocampic discharge formation

Radiation intensity profiles at various stages of apocampic discharge formation

Modeling of Tungsten Behavior in Plasma of T-10 Tokamak

The results of numerical modeling of impurity concentration profiles of tungsten ions for discharges with ohmic heating (OH) on the T-10 tokamak with W limiter (for Zeff ≈ 1) are described. It is shown that in OH discharges the maximum values of relative concentrations for each tungsten ion state are located on their radii of coronal equilibrium. Fulfillment of coronal equilibrium on the T-10 tokamak makes it possible to determine the full radiation intensity from the total concentration of tungsten ions. The results show that modeling of the Prad(r) profile for tungsten using currently accepted scaling of anomalous transport coefficients of light and moderate impurities for T-10 plasma does not make it possible to obtain complete alignment with the experimental data. The dependences of tungsten radiation intensity profiles on different published data on excitation, ionization, recombination rates, and anomalous transport coefficients are shown in the paper. A conclusion about the value of the anomalous diffusion coefficient and its radial distribution for heavy impurity (tungsten) in OH discharges at the T-10 tokamak is made.

Radiation Intensity Profiles at Different Stages of the Formation of Apokamp Discharge

Experimental studies of the heat release processes in the apokamp discharge were carried out via the plotting of intensity charts. The procedure was verified with measurement techniques similar to those used in the operation of a disappearing filament pyrometer. A criterion was formulated for its applicability for the study of apokamp discharge in air. The intensity charts obtained at different stages of the formation of discharge confirm the need for gas heating near the discharge channel to form streamers.

Invited Article: Refined analysis of synchrotron radiation for NIST’s SURF III facility

We have developed a new method for the exact calculation of synchrotron radiation for the National Institute of Standards and Technology Synchrotron Ultraviolet Radiation Facility, SURF III. Instead of using the Schwinger formula, which is only an approximation, we develop formulae based on Graf's addition theorem for Bessel functions and accurate asymptotic expansions for Hankel functions and Bessel functions. By measuring the radiation intensity profile at two distances from the storage ring, we also confirm an apparent vertical emittance that is consistent with the vertical betatron oscillations that are intentionally introduced to extend beam lifetime by spreading the electron beam spatially. Finally, we determine how much diffraction by beamline apertures enhances the spectral irradiance at an integrating sphere entrance port at the end station. This should eliminate small but treatable components of the uncertainty budget that one should consider when using SURF III or similar synchrotrons as standard, calculable sources of ultraviolet and other radiation.

Optimizing the 391-nm lasing intensity from ionized nitrogen molecules in 800-nm femtosecond laser fields

We investigate the 391-nm lasing dynamics from ionized nitrogen molecules in 800-nm femtosecond laser fields. By comparing the radiation intensity, spectrum shape, and temporal profile of the 391-nm lasing at various experimental conditions, we conclude that the lasing dynamics contains not only the generation and the decay of ionized nitrogen molecules, but also the seed-built coherence among emitters as well as the propagation effect in the plasma filamentation. These results provide reliable guidance for optimizing the 391-nm lasing from ionized nitrogen molecules in 800-nm femtosecond laser fields, which have potential applications for remote sensing in the atmosphere.

Pulverized Coal-Fired Flame Temperature and Emissivity Measurement Based on Spectral Analysis and the Two-Color Method

A method for judging the gray property of flames based on spectral analysis and the two-color method for determining the temperature and emissivity of flame has been demonstrated. A calibrated spectrometer system was used for the data acquisition of the radiation intensity profile of a flame over a range of wavelengths (200 – 1100 nm). The wavelength range that meets the gray body assumption, in which the emissivity can be assumed as a constant, can be determined from the emissivity profile obtained by spectral analysis and the two-color method. Then the temperature and emissivity of the flame and their relative mean square deviations were calculated within that range. Experiments were conducted on pulverized coal-fired flames in a commercial 300MW boiler furnace. The results show that the coal-fired flame can be assumed as gray body between 500 nm and 1000 nm, and the temperature and emissivity calculation results of coal-fired flames are found to be in reasonable agreement with results using other methods from the literature.

Influence of atomic physics on EDGE2D-EIRENE simulations of JET divertor detachment with carbon and beryllium/tungsten plasma-facing components

The EDGE2D-EIRENE code is applied for simulation of divertor detachment during matched density ramp experiments in high triangularity, L-mode plasmas in both JET-Carbon (JET-C) and JET-ITER-Like Wall (JET-ILW). The code runs without drifts and includes either C or Be as impurity, but not W, assuming that the W targets have been coated with Be via main chamber migration. The simulations reproduce reasonably well the observed particle flux detachment as density is raised in both JET-C and JET-ILW experiments and can better match the experimental in-out divertor target power asymmetry if the heat flux entering the outer divertor is artificially set at around 2–3 times that entering the inner divertor. A careful comparison between different sets of atomic physics processes used in EIRENE shows that the detachment modelled by EDGE2D-EIRENE relies only on an increase of the particle sinks and not on a decrease of the ionization source. For the rollover and the beginning of the partially detached phase, the particle losses by perpendicular transport and the molecular activated recombination processes are mainly involved. For a deeper detachment with significant target ion flux reduction, volume recombination appears to be the main contributor. The elastic molecule-ion collisions are also important to provide good neutral confinement in the divertor and thus stabilize the simulations at low electron temperature (Te), when the sink terms are strong. Comparison between EDGE2D-EIRENE and SOLPS4.3 simulations of the density ramp in C shows similar detachment trends, but the importance of the elastic ion-molecule collisions is reduced in SOLPS4.3. Both codes suggest that any process capable of increasing the neutral confinement in the divertor should help to improve the modelling of the detachment. A further outcome of this work has been to demonstrate that key JET divertor diagnostic signals—Langmuir probe Te and bolometric tomographic reconstructions—are running beyond the limit of validity in high recycling and detached conditions and cannot be reliably used for code validation. The simulations do, however, reproduce the trend of the evolution of the line integrated bolometer chord measurements. The comparison between the code results and high-n Balmer line radiation intensity profiles confirms that a strong volume recombination is present during the experimental detachment and may play a role in this process, as suggested by the code.

Microwave radiation in the upper atmosphere of the earth during strong geomagnetic disturbances

The influence of N2 and O2 molecules on spontaneous microwave radiation spectrum was studied over the decimeter range. This radiation appears in the D and E upper earth atmosphere layers during strong magnetic storms. It was shown to be caused by radiation transitions between medium-perturbed orbitally degenerate Rydberg atom and molecule states A** that occur without changes in the principal quantum number, δn = 0. The available experimental data were used to calculate the dependences of orbitally degenerate state populations on the density of medium and electron flux and temperature. Effective radiation bands were constructed for transitions between highly excited quasi-molecule levels A**N2 and A**O2. The emission spectrum was shown to be inhomogeneous and contain three frequency regions in which a noticeable decrease in the intensity of radiation occurred. The physical reason for the formation of these regions was a shift of the emission spectra of quasi-molecules containing unexcited N2 and O2 molecules. The frequency profiles of radiation intensity within these frequency regions were calculated as depending on the storm level. Radiation profiles were shown to noticeably change as the storm level increased, they strongly increased close to the right region edge corresponding to high transition frequencies. Nonmonotonic behavior of this profile in the middle of the lower region was observed; this was related to emission spectrum inhomogeneity. A sharp increase in radiation intensity as the magnetic storm level increased occurred in the region of frequencies situated close to the right edge of the upper region (50–100 GHz), which was most interesting for biophysical studies of the action of microwave radiation on living organisms during strong geomagnetic disturbances.

A simple judgment method of gray property of flames based on spectral analysis and the two-color method for measurements of temperatures and emissivity

A method for judging the gray property of flames based on spectral analysis and the two-color method for determining the temperature and emissivity of a flame has been demonstrated. A calibrated spectrometer system was used for the data acquisition of the radiation intensity profile of a flame over a range of wavelengths (200–1100nm). The wavelength range that meets the gray body assumption, in which the emissivity can be assumed to be constant, can be determined from the emissivity profile obtained by spectral analysis and the two-color method. Then the temperature and emissivity of the flame and their relative mean square deviations were calculated within that range. Experiments were conducted on solidified gasoline and red phosphorus flames, and pulverized coal-fired flames in a commercial 420ton/h boiler furnace. The results show that the gasoline flame can be assumed to be a gray body in the range between 550 and 900nm, for the coal-fired flame the range is between 500 and 1000nm; while the red phosphorus flame cannot be assumed to be a gray body within the measurement wavelength range. The temperature and emissivity calculation results of coal-fired flames are found to be in reasonable agreement with results using other methods described in the literature. The wavelength interval in the two-color method to calculate temperature is also discussed.

Optimal Multileaf Collimator Leaf Sequencing in IMRT Treatment Planning

We consider a problem dealing with the efficient delivery of intensity modulated radiation therapy (IMRT) to individual patients. IMRT treatment planning is usually performed in three phases. The first phase determines a set of beam angles through which radiation is delivered, followed by a second phase that determines an optimal radiation intensity profile (or fluence map). This intensity profile is selected to ensure that certain targets receive a required amount of dose while functional organs are spared. To deliver these intensity profiles to the patient, a third phase must decompose them into a collection of apertures and corresponding intensities. In this paper, we investigate this last problem. Formally, an intensity profile is represented as a nonnegative integer matrix; an aperture is represented as a binary matrix whose ones appear consecutively in each row. A feasible decomposition is one in which the original desired intensity profile is equal to the sum of a number of feasible binary matrices multiplied by corresponding intensity values. To most efficiently treat a patient, we wish to minimize a measure of total treatment time, which is given as a weighted sum of the number of apertures and the sum of the aperture intensities used in the decomposition. We develop the first exact algorithm capable of solving real-world problem instances to optimality within practicable computational limits, using a combination of integer programming decomposition and combinatorial search techniques. We demonstrate the efficacy of our approach on a set of 25 test instances derived from actual clinical data and on 100 randomly generated instances.

Optical Investigation of the Plasma Jet of Vacuum-Arc Cathode Spot

The results of the optical study of the plasma jet of the cathode spot of a freely burning vacuum arc with copper electrodes at a current of 60 A are given, as well as of the arc stabilized with a uniform axial magnetic field of induction up to 0.18 T. The axial and radial profiles of radiation intensity for different ionization states of copper - the atom and the single and double ions - were studied. The profiles of the distribution temperatures of the atom and the single ion were determined. The temperature of electrons is estimated on the periphery of the jet. The obtained results are discussed and compared with those of a mathematical simulation.

Radiation intensity of lignite-fired oxy-fuel flames

The radiative heat transfer in oxy-fuel flames is compared to corresponding conditions in air-fuel flames during combustion of lignite in the Chalmers 100 kW oxy-fuel test facility. In the oxy-fuel cases the flue-gas recycle rate was varied, so that, in principle, the same stoichiometry was kept in all cases, whereas the oxygen fraction in the recycled flue-gas mixture ranged from 25 to 29 vol.%. Radial profiles of gas concentration, temperature and total radiation intensity were measured in the furnace. The temperature, and thereby the total radiation intensity of the oxy-fuel flames, increases with decreasing flue-gas recycle rate. The ratio of gas and total radiation intensities increases under oxy-fuel conditions compared to air-firing. However, when radiation overlap between gas and particles is considered the ratios for air-firing and oxy-fuel conditions become more similar, since the gas-particle overlap is increased in the CO 2-rich atmosphere. A large fraction of the radiation in these lignite flames is emitted by particles whose radiation was not significantly influenced by oxy-fuel operation. Therefore, an increment of gas radiation due to higher CO 2 concentration is not evident because of the background of particle radiation, and, the total radiation intensities are similar during oxy-fuel and air-fuel operation as long as the temperature distributions are similar.

Estimation of Radiative Properties for Human Skin by Reflection Profile Measurement

An inverse method for estimating radiative properties of scattering and absorbing media has been developed. This method allows us to estimate radiative properties of human skin in vivo in wide range of wavelength. In this method, a target planar medium is non-uniformly irradiated by stripe-like radiation that has passed multi-slits, and the intensity profile of radiation reflected by the medium is measured. The radiative properties, extinction coefficient and albedo, are estimated by an inverse analysis based on the intensity profile of radiation. We applied the present method for human skin, and estimated the extinction coefficient and the albedo of skin in visible range of wavelength.

Selective Photocatalytic Oxidation of 4-Methoxybenzyl Alcohol to p-Anisaldehyde in Organic-Free Water in a Continuous Annular Fixed Bed Reactor

Photocatalytic oxidation of 4-methoxybenzyl alcohol to p-anisaldehyde was performed in water organic-free solutions by using a fixed bed continuous photoreactor containing Pyrex beads on which a TiO2 home prepared photocatalyst was supported. The influence of liquid flow rate, inlet alcohol concentration and catalyst amount on the photoprocess was studied. The highest selectivity to p-anisaldehyde was about 47% being CO2, the other main oxidation product; traces of 4-methoxybenzoic acid were also detected. The radiation field inside the photoreactor has been modelled by applying the Monte Carlo method thus allowing the determination of the local volumetric rate of photon absorption (LVRPA). It was found that the radiation intensity profile sharply decreases inside the bed so that an important aliquot of the bed is not active for the photoreaction occurrence. This finding indicates that the reactivity results, obtained by measuring the concentration values of reagents and products at the exit of photoreactor, can not be used jointly with the radiation modelling ones for determining the dependence of reaction kinetics on light intensity. The Langmuir-Hinshelwood approach has been satisfactorily applied for modelling the photoreactivity results and the values of all the model parameters have been determined.

Investigation of metastable autonomous plasma formations from atmospheric discharges

A 10 kV, 2 kW laboratory transformer was used to generate atmospheric discharges at spherical brass electrodes 15 mm in diameter and 8 mm long. After ignition, a moving electric arc generated an autonomous plasma formation. The lifetime of the autonomous plasma formations, measured from video frames of 40 ms in succession, depends approximately linearly on their geometrical size. By applying a cylindrical-symmetrical back projection transformation to the images of the autonomous plasma formations and computing the radiation intensity profiles, a vortexlike structure of the plasma formations was detected. Autonomous plasma vortices 2.5 cm in diameter showed lifetimes of about 120 ms. No significant influence of the ambient air temperature, ranging from 10°C to 30°C, was found, nor on the relative air humidity, ranging from 10% to 100%. The radiation temperature of the plasma vortices were estimated by fitting blackbody radiation curves to the measured intensities at four spectral wavelengths provided by optical-spectrum filters. The average radiation temperature of the autonomous plasma vortices was estimated at about 2000 K, having a temperature decay of about 300 K/ms. The reproducible formation of metastable autonomous plasma vortices as described in the literature can be verified at the laboratory scale. Its geometrical intensity profile and radiation temperature can be approximated and its lifetime measured. The described phenomenon could possibly be accounted as a physical explanation model for the occurrence of natural ball lightning. Further investigations should focus on experimental determination of the flow profile and to provide a self-consistent theoretical model for the description of the energy-storage and transfer mechanisms.

F221 空間分解反射光計測に基づく皮膚のふく射物性の推定(バイオ・食品における輸送特性の測定2)

An inverse method for estimating radiative properties of scattering and absorbing media has been developed. This method allows us to estimate radiative properties of human skin in vivo in wide range of wavelength. In this method, a target planar medium is non-uniformly irradiated by radiation that has passed multi-slits, and the intensity profile of radiation reflected by the medium is measured. The radiative properties, such as extinction coefficient and albedo are estimated by an inverse analysis based on the intensity profile of radiation. We applied the present method for human skin, and estimated the extinction coefficient and albedo of the skin in the visible range of wavelength.