Relative Power Distribution Research Articles

基于反应时间的中间视觉道路照明功率密度分析及显色性能研究

A research method of analysis of the road lighting source safety and energy-saving properties under the human mesopic conditions was given. By constructing the reaction time test system for road lighting under the mesopic vision,the luminous efficiency model was established and luminous efficiency curve was obtained. By using this model,the evaluation method of energy efficiency based on the lighting power density was given. Using the calculation and analysis method of the color-rendering properties based on the color-rendering index,the effect of the changes in relative spectral power distribution on the color of light source was discussed under Luv uniform color space,and the function expression between the dominant wavelength of the light source and color-rendering index was established,which can be used to obtain the relationship between human sensitivity and light source color of each wavelength point. The above method was verified by the reaction time simulation test and the definition of the road lighting picture calculation experiment. The results show that the green-white light source with dominant wavelength of 540- 550 nm has the best power-saving and color-rendering properties under the mesopic vision.

Spectral and photopic studies for high intensity discharge (HID) lamps

Outdoor lighting sources such as High Intensity Discharge lamps (HID) are common in these days. This research is focusing on the relation between the spectral power distribution and luminous efficiency function V (λ ), which describes the average spectral sensitivity of human visual perception of brightness. The most useable HID lamps inside Egyptian markets are high pressure mercury (HPM), high pressure sodium (HPS) and metal halide (MH). A set up based on single monochromator and integrating sphere for relative spectral power distribution and absolute luminous flux measurements are used, respectively. The accompanied standard uncertainties with the measurements are evaluated.

Power and Civil War Termination Bargaining

Traditional bargaining theory predicts that groups will demand and concede as much as their relative power allows. However, scholars who study bargaining in the civil war context suggest that governments often overcompensate a rebel group to reach an agreement because the rebel group typically feels insecure. This paper argues that depending on the relative power distribution between groups, either a rebel group or government involved in a civil war can feel insecure at the bargaining table. The weaker bargaining participant, whether government or rebel, is expected to feel insecure and thus demand more political power in a postwar state than its power share predicts, while the stronger group is expected to be willing to overcompensate the weaker group to assuage its security concerns. Using a new data set on political power-sharing bargaining during civil war, my analysis supports this expectation.

PWR experimental benchmark analysis using WIMSD and PRIDE codes

The PWR experimental benchmark problem defined by ANS was analyzed using WIMSD and PRIDE codes. Different modeling methodologies were used to calculate the infinite and effective multiplication factors. Relative pin power distributions were calculated for infinite lattice and critical core configurations, while reaction ratios were calculated for infinite lattice only. The discrete ordinate method (DSN) and collision probability method (PERSEUS) were used in each calculation. Different WIMSD cross-section libraries based on ENDF/B-VI.8, ENDF/B-VII.0, IAEA, JEF-2.2, JEFF-3.1 and JENDL-3.2 nuclear data files were also employed in the analyses. Comparison was made with experimental data and other reported results in order to find a suitable strategy for PWR analysis.

Neutronic calculation and power maps investigation of PWR critical lattice experiments using WIMSD-5B and CITVAP v3.1 codes

The calculation of integral parameters and power distribution is a very important task for fuel assembly design and whole core safety analysis. In this work, we used Monte Carlo (MCNP5) and deterministic lattice cell code WIMSD-5B with the diffusion code CITVAP v3.1 to assess the accuracy of neutronic calculations of three PWR lattice benchmark problems defined by the ANS Ad Hoc Committee on Reactor Physics Benchmarks. The code results for the integral parameters and relative pin power distribution are compared to measured values and the previous calculations obtained from some of organisations participated in this benchmark. The results demonstrate that the codes showed very good estimates of both the integral parameter and power distribution for the critical core and lattice configuration for the three different benchmarks selected.

Measurements of UV-A radiation and hazard limits from some types of outdoor lamps

Illumination using artificial light sources is common in these days. Many manufactures are paying for the design of lamps depending on high efficacy and low UV hazards. This research is focusing on the most useable lamps in the Egyptian markets; high pressure mercury (HPM), metal Halide (MH), and high pressure sodium (HPS). A set up for relative spectral power distribution based on single monochromator and UVA silicon detector for absolute irradiance measurements are used. The absolute irradiance in (W/m2 ) in UVA region of the lamps and their accompanied standard uncertainty are evaluated.

Coupled neutronic/thermo-hydraulic analysis of water/Al2O3 nanofluids in a VVER-1000 reactor

In this paper we investigate the thermal–hydraulic and neutronic attributions of using nanoparticles in the primary cooling system of a VVER-1000 reactor. The coupled analysis of the nanofluid core is performed by using DRAGON, DONJON and a thermal–hydraulic model that solves the governing momentum, energy, and mass equations. The applied approach is validated by comparing the results with the final safety analysis report (FSAR) of the plant. Finally, critical boric acid, relative power distribution, pressure drop, and temperature distributions of fuel, clad and coolant are considered for water/Al2O3 nanofluid. It is observed that low volume fraction of the nanoparticles has a minimum impact in critical boric acid up to about 3% and relative power distribution about 2% at maximum while the heat transfer is enhanced in comparison to pure water.

Methodology for Measurement of the Blue Light Hazard of Light-Emitting Diodes with Imaging Luminance Meter

Most of the measurement methods for blue light hazard (BLH) evaluation are based on radiance, which are too complex and hard to find out the highest radiance. We proposed a methodology for measurement of BLH with imaging luminance meter. We measured the relative spectral power distribution with a spectrometer and the maximum luminance with an imaging luminance meter for LEDs and compact fluorescent lamps, and calculated the BLH weighted radiance. The BLH efficacy and the upper limit of luminance with blue light safe of various light sources were also calculated on the basis of the BLH weighted function. The results show absolute blue light safe can be obtained if the luminance is limited to 100 kcd m2 for color temperature lower than 6500 K. LEDs with high color temperature, especially those without diffused window, have potential risk of BLH. Our method can be used in online measurement of the BLH of LEDs.

Irradiance‐independent camera color calibration

AbstractFor a digital color camera to represent the colors in the environment accurately, it is necessary to calibrate the camera RGB outputs in terms of a colorimetric space such as the CIEXYZ or sRGB. Assuming that the camera response is a linear function of scene luminance, the main step in the calibration is to determine a transformation matrix M mapping data from linear camera RGB to XYZ. Determining M is usually done by photographing a calibrated target, often a color checker, and then performing a least‐squares regression on the difference between the camera's RGB digital counts from each color checker patch and their corresponding true XYZ values. To measure accurately the XYZ coordinates for each patch, either a completely uniform lighting field is required, which can be hard to accomplish, or a measurement of the illuminant irradiance at each patch is needed. In this article, two computational methods are presented for camera color calibration that require only that the relative spectral power distribution of the illumination be constant across the color checker, while its irradiance may vary, and yet resolve for a color correction matrix that remains unaffected by any irradiance variation that may be present. © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 540–548, 2014

Power parity and peace? The role of relative power in civil war settlement

Theories of civil war highlight how relative power affects conflict onset, dynamics, strategy, outcome, and duration. Yet most studies of civil war have not been able to capture rebel power adequately and often rely on national-level characteristics to infer relative power distributions. This study addresses this shortcoming by using a troop strength measure to test arguments about how relative power affects the likelihood of civil conflict settlement. Drawing on the international crisis bargaining literature, while noting the inherent differences between interstate and intrastate conflicts, this study argues that the condition of power parity increases the likelihood of negotiated settlement and ceasefire. Weak rebels are unable to achieve concessions through negotiation since governments view them as minor threats. Yet governments have difficulty defeating weak rebels due to an emphasis on guerrilla warfare. On the other end of the spectrum, rebels that are superior to the government in strength are unlikely to settle given their power advantage. Strong rebels that can rival the strength of the government (i.e. they are near parity) can exact more concessions because fighting at parity exposes information about how long each side can hold out while escalating the costs of war, giving each side a greater incentive to negotiate and eventually seek a ceasefire or peace agreement. This argument is supported using data on 112 dyads in the post-Cold War period.

Influence of the temperature dependent spectral power distribution of light-emitting Diodes on the illuminance responsivity of a photometer

Accurate optical measurements of LEDs are crucial because of the increasing popularity of LEDs. However, a photometer with a V(λ) filter spectrum curve may yield large errors when it is used for photometric measurements of colored LEDs. The junction-dependent light output and spectral distribution of LEDs also introduce measurement errors of the measured photometric characteristics. For the accurate measurements of LEDs, the c(St,Ss) factors were used to estimate the possible deviation in the photometric measurement of colored LEDs with various junction temperatures using commercial and industrial grade photometer heads. The spectral measurements of LEDs with specified junction temperature were conducted using a miniature fiber-optic spectrometer, and the relative spectral power distributions of LEDs were used to calculate the spectral mismatch correction c(St,Ss) factors of the photometer heads. Therefore, the c(St,Ss) factors of colored LEDs were calculated according to the temperature dependent spectral power distributions with various junction temperatures, and these factors were used to estimate the possible deviation in the photometric measurement of colored LEDs. The estimation of the possible deviation in the photometric measurement shows that photometers with excellent relative spectral responsitivities must be used for accurate measurement; otherwise, careful calibration must be conducted when using a photometer with inferior relative spectral responsitivity of the photopic filter.

Behavioral and cortical EEG evaluations confirm the roles of both CCKA and CCKB receptors in mouse CCK-induced anxiety

This study investigated the roles of cholecystokinin (CCK)A and CCKB receptors on CCK-4-induced anxiety-like behaviors in mice through behavioral and neural evaluations. Anxiety-like behaviors in mice were induced by an intracerebroventricular (i.c.v.) administration of CCK-4, which can bind to both CCKA and CCKB receptors. The effects of CCKA and CCKB receptor antagonists (devazepide and CI-988, respectively) were examined using mouse anxiety tests (elevated-plus maze and light–dark box) and also by examining neuronal activities through EEG monitoring and c-Fos immunohistochemistry in the cortex and amygdala. CCK-4 (3μg/kg of body weight i.c.v.) significantly induced mouse anxiety-like behaviors in the anxiety tests and also affected their EEG patterns with respect to pre-drug tracing, resulting in increase in spectral power in relative power distribution in the delta and theta bands (0.5–5Hz frequency bands) and also in increase in c-Fos immunopositive neuron counts. These CCK-4 effects were completely suppressed by 1.0mg/kg CCKB receptor antagonist, CI-988, while the same amount of CCKA receptor antagonist, devazepide was partly able to suppress the same effects. These findings indicated that not only CCKB receptors but also CCKA receptors in the brain play important roles in regulating anxiety-like behaviors in mice. The present study also proposed a possibility that cortical EEG is useful for assessing anxiety.

Accuracy simulation of an LED based spectrophotometer

In this paper, the achievable accuracy of a reflectance spectrophotometer based on 18 LEDs of different peak wavelengths in the range of 390–710nm for object illumination is reported. For simulating the accuracy, reflectance spectra of the color target ColorChecker® have been used. By weighting the reflectance spectra of the target with measured relative power distribution spectra of the employed LEDs, simulated spectral reflectance values of the target are obtained. For calculating color values, unique wavelength values must be assigned to the simulated spectral sample values. LEDs can be characterized by several wavelength parameters. It has been shown that, without applying a correction procedure, assigning the centroid-wavelength of the LEDs as color calculation basis delivers the best results. But if a linear correction matrix is introduced, an optimized equidistant wavelength assignment delivers the best results. The mean achievable precision is sufficient to determine color values below ΔEab<0.3.

Helical structure of complementary colors' relative spectral distribution function

I report a curious double helix in psychophysical data. As recently reported, color complementarism structures at least 40 functional roles in vision including all Red-, Green-, Blue-peaked functions (e.g., color matching functions, Helmholtz–Kohlrausch effect, saturation discrimination, lightness discrimination, and wavelength discrimination). These can be modeled from the relative spectral power distribution (SPD) function of complementary colors (at requisite power ratios to neutralize complements). So, the SPDs three-dimensional (3D) structure is of interest. Extended to the hue cycle, the SPD is plotted in a rectilinear graph of wavelength versus wavelength with radiance vertical to the plane. In this rectilinear color mixture space, the white locus representing the illuminant chromaticity is not a single point (representing the junction of complementary pairs of wavelengths) but a sinusoidal curve whose 3D structure is a double helix, representing an SPD and its complementary SPD. The structure's purpose is possibly to store and access global complementary colors data across illuminants. © 2012 Wiley Periodicals, Inc. Col Res Appl, 38, 292–296, 2013

Instability Analysis in Peach Bottom NPP Using a Whole Core Thermalhydraulic-Neutronic Model with RELAP5/PARCS v2.7

In this paper we present the results from a BWR stability analysis performed on an operating point, called PT_UPV, of Peach Bottom NPP. This point is inside the exclusion region and it is achieved departing from test point 3 by a control rod movement as it is usually performed in Nuclear Power Plants. The simulation has been made with the coupled code RELAP5-MOD3.3/PARCS v2.7. The thermalhydraulic model includes all the reactor vessel components: jet pumps, recirculation pumps, downcomer, reactor core and also the separator and the dryer. The reactor core has been modeled with 72 thermalhydraulic channels, 71 represent the active core and 1 represents the core bypass. The reactor core thermalhydraulic-to-neutronic representation (mapping) has been divided in four quadrants according to the first and second power harmonics (Lambda modes) obtained previously with the VALKIN code. This mapping was chosen in order not to condition the oscillation pattern. The purpose of this study is to qualify this coupled code against this kind of 3D complex accidents that take place inside the core. The calculated results show that point PT_UPV is an unstable point and the obtained relative axial power distribution shows a bottom-peaked profile, which is characteristic of unstable cores.

Automatic discrimination of underwater acoustic signals generated by teleseismic P-waves: A probabilistic approach

[1] We propose a new probabilistic scheme for the automatic recognition of underwater acoustic signals generated by teleseismic P-waves recorded by hydrophones in the ocean. The recognition of a given signal is based on the relative distribution of its power among different frequency bands. The signal's power distribution is compared with a statistical model developed by analyzing relative power distributions of many signals of the same origin and a numerical criterion is calculated, which can serve as a measure of the probability for the signal to belong to the statistical model. Our recognition scheme was applied to 6-month-long continuous records of seven ocean bottom hydrophones (OBH) deployed in the Ligurian Sea. A maximum of 94% of all detectable teleseismic P-waves recorded during the deployment of the OBHs were recognized correctly with no false recognitions. The proposed recognition method will be implemented in autonomous underwater robots dedicated to detect and transmit acoustic signals generated by teleseismic P-waves.

Peach bottom instability analysis with a RELAP5/PARCSv2.7 detailed thermal-hydraulic–neutronic model

Abstract In this work, BWR stability analysis has been performed on an operating point (PT_UPV) of Peach Bottom NPP which is inside the exclusion region in the operating power-flow map. The simulation has been made with the coupled code RELAP5-MOD3.3/PARCSv2.7. This point is achieved departing from test point 3 by a control rod movement as it is usually performed in Nuclear Power Plants. The thermal-hydraulic model is a detailed model that includes all the reactor vessel components: jet pumps, recirculation pumps, downcomer, reactor core and also the separator and the dryer. The reactor core has been modeled with 72 thermal-hydraulic channels, 71 represent the active core and 1 represents the core bypass. The reactor core thermal-hydraulic to neutronic representation (mapping) has been divided in four quadrants according to the first and second power harmonics (Lambda modes) obtained previously with the VALKIN code. This mapping was chosen in order not to condition the oscillation pattern. The transient starts with the control rod movement. The calculated results show that point PT_UPV is an unstable point and the obtained relative axial power distribution shows a bottom-peaked profile, which is characteristic of unstable cores.

Longitudinal ambulatory measurements of gait abnormality in dystrophin-deficient dogs

BackgroundThis study aimed to measure the gait abnormalities in GRMD (Golden retriever muscular dystrophy) dogs during growth and disease progression using an ambulatory gait analyzer (3D-accelerometers) as a possible tool to assess the effects of a therapeutic intervention.MethodsSix healthy and twelve GRMD dogs were evaluated twice monthly, from the age of two to nine months. The evolution of each gait variable previously shown to be modified in control and dystrophin-deficient adults was assessed using two-ways variance analysis (age, clinical status) with repeated measurements. A principal component analysis (PCA) was applied to perfect multivariate data interpretation.ResultsSpeed, stride length, total power and force significantly already decreased (p < 0.01) at the age of 2 months. The other gait variables (stride frequency, relative power distributions along the three axes) became modified at later stages. Using the PCA analysis, a global gait index taking into account the main gait variables was calculated, and was also consistent to detect the early changes in the GRMD gait patterns, as well as the progressive degradation of gait quality.ConclusionThe gait variables measured by the accelerometers were sensitive to early detect and follow the gait disorders and mirrored the heterogeneity of clinical presentations, giving sense to monitor gait in GRMD dogs during progression of the disease and pre-clinical therapeutic trials.

External quantum efficiency of microcavity planar emitting devices

The calculation models of the external quantum efficiency for the planar surface emitting devices are presented with considering their spatial distribution of radiance/luminance and relative spectral power distribution. These models can be applied to all kinds of planar surface emitting devices including OLEDs, VCSEL, MOLED, MCLED and planar THz emitting devices. Two planar emitting devices with and without cavity are fabricated with the structure of Glass /DBR /ITO /NPB /Alq ∶C545T /Alq /LiF /Al and Glass /ITO /NPB /Alq ∶C545T /Alq /LiF /Al. The external quantum efficiencies are calculated at different current densities using the corresponding model. The external quantum efficiency of the cavity device is close to 1.5% at a current density of 14 A/m2 and brightness of 100 cd/m2, and reaches 2% around 0.14 A/m2 and 2.2 cd/m2.

The experimental determination and evaluation of the three-dimensional fission density distribution of the IPEN/MB-01 research reactor facility for the IRPhE project

Experiments for the determination of the three-dimensional fission density distribution were successfully carried out at the IPEN/MB-01 research reactor facility. The experiment is of very good quality for utilization in the benchmark of computer codes and related nuclear data library commonly used for the calculation of fission density distribution in reactor cores. The complete experimental data set comprises a very massive set of measured fission density distribution. The experiment was evaluated and included in the IRPhE handbook. Two calculation methodologies were employed for the theoretical analysis of the proposed benchmark; one stochastic (MCNP-5) and the other one deterministic (NJOY/AMPX-II/TORT); both utilizing ENDF/B-VII.0 as the source of nuclear data. The theory/experiment comparison reveals in general a good agreement for both methodologies. However, MCNP-5 results are in a better shape than those of TORT. TORT underestimates the relative power distribution mainly in the axial upper part of the fuel rod. This effect is mostly credited to the over-prediction of the control bank worth.