Mean Angle Of Incidence Research Articles

Ion thruster accelerator grid erosion mechanism under extreme conditions of cylindrical erosion and chamfer erosion

In this paper, the abnormal experimental phenomenon on barrel erosion under extreme working conditions in the ultra-long life experiment (>10000 h) of ion thruster ion optics is studied by the Immersed-Finite-Element Particle-In-Cell Monte-Carlo-Collision (IFE-PIC-MCC) method and the grid erosion evaluation model. The transport process of beam ions and Charge Exchange (CEX) ions in the grid system, and the characteristics and mechanisms of the aperture barrel erosion under extreme erosion conditions (i.e. the cylindrical erosion and chamfer erosion) were systematically studied. Thanks to the advantage of the IFE method for dealing with complex boundaries in structured mesh, the aperture barrel erosion morphology of the accelerator grid is reconstructed accurately based on the experimental results. The results show that, with the evolution of working conditions, the mechanism of the aperture barrel erosion changes significantly, which relies heavily on the accelerator grid morphology. The change of the accelerator grid aperture barrel morphology has a significant effect on the behavior of CEX ions, and only affects the local electric field distribution, but has no effect on the upstream plasma sheath. As the erosion progresses, the erosion position moves downstream along the grid aperture axis direction, and the erosion range becomes narrower. Regardless of the erosion phase, the erosion rate of the CEX ions located downstream of the decelerator grid is the largest. The erosion rate is related to the mean incident energy and angle, and their variation is closely related to the position and trajectory of CEX ions.

Technical Comparison of Treatment Efficiency of Magnetic Resonance-Guided Focused Ultrasound Thalamotomy and Pallidotomy in Skull Density Ratio-Matched Patient Cohorts.

ObjectiveMR-guided focused ultrasound (MRgFUS) is increasingly being used to treat patients with essential tremor (ET) and Parkinson's disease (PD) with thalamotomy and pallidotomy, respectively. Pallidotomy is performed off-center within the cranium compared to thalamotomy and may present challenges to therapeutic lesioning due to this location. However, the impact of target location on treatment efficiency and ability to create therapeutic lesions has not been studied. This study aimed to compare the physical efficiency of MRgFUS thalamotomy and pallidotomy.MethodsTreatment characteristics were compared between patients treated with thalamotomy (n = 20) or pallidotomy (n = 20), matched by skull density ratios (SDR). Aspects of treatment efficiency were compared between these groups. Demographic and comparative statistics were conducted to assess these differences. Acoustic field simulations were performed to compare and validate the simulated temperature profile for VIM and GPi ablation.ResultsLower SDR values were associated with greater energy requirement for thalamotomy (R2 = 0.197, p = 0.049) and pallidotomy (R2 = 0.342, p = 0.007). The impact of low SDR on efficiency reduction was greater for pallidotomy, approaching significance (p = 0.061). A nearly two-fold increase in energy was needed to reach 50°C in pallidotomy (10.9kJ) than in thalamotomy (5.7kJ), (p = 0.002). Despite lower energy requirement, the maximum average temperature reached was higher in thalamotomy (56.7°C) than in pallidotomy (55.0°C), (p = 0.017). Mean incident angle of acoustic beams was lesser in thalamotomy (12.7°) than in pallidotomy (18.6°), (p < 0.001). For all patients, a lesser mean incident angle correlated with a higher maximum average temperature reached (R2 = 0.124, p = 0.026), and less energy needed to reach 50°C (R2=0.134, p = 0.020). Greater skull thickness was associated with a higher maximum energy for a single sonication for thalamotomy (R2 = 0.206, p = 0.045) and pallidotomy (R2 = 0.403, p = 0.003). An acoustic and temperature field simulation validated similar findings for thalamotomy and pallidotomy in a single patient.ConclusionThe centrally located VIM offers a more efficient location for therapeutic lesioning compared to GPi pallidotomy in SDR matched cohort of patients. The impact on therapeutic lesioning with lower SDR may be greater for pallidotomy patients. As newer off-center targets are investigated, these findings can inform patient selection and treatment requirements for lesion production.

External mean flow effect on sound transmission through composite sandwich structures filled with porous materials

A theoretical model is developed to investigate the influence of external mean flow on sound transmission loss (STL) through composite sandwich panels filled with porous materials. The equations of the motions for the composite laminate plates are established by adopting the first-order shear deformation theory. The porous materials in between the sandwich structures are characterized by an equivalent fluid model. Employing the fluid-structure coupling condition, the displacement continuity at fluid-structure interfaces is guaranteed. To validate the proposed theoretical model, a comparison among the present theoretical predictions, the existing theoretical and experimental results are executed, with overall agreements achieved. A systematical investigation is carried out to explore the influences of the external mean flow, incidence angle and laminate scheme on the coincidence frequency and sound transmission loss of the sandwich structures. This work provides a helpful guideline for the vibroacoustic design of composite sandwich structures.

Replacing silver by aluminum in solar mirrors by improving solar reflectance with dielectric top layers

Silver is a strategic material for renewable energy. Among other applications related to PV, it is used as reflective layer in solar mirrors for concentrated solar power (CSP), thanks to its high reflectance in the whole solar range. CSP plants require large mirror areas, typically in the 0.1 to 1 km2. However the estimated reserves of silver do not exceed 20 years. To sustain the deployment of CSP as a valuable input in the future energy mix, silver must be replaced with a less critical material, ideally low cost. In this theoretical study we propose to replace silver by aluminum, adding a dielectric multilayer coating on top, to reach similar optical performance. This design is inspired by Bragg mirrors but differs in that the stack parameters (layer thicknesses) are individually optimized, so as to maximize solar reflectance. A thin aluminum layer with MgF2/TiO2 aperiodic stack on top can theoretically reach solar reflectance of 96.1%, higher than silver (95.5%). Other materials are also found suitable: SiO2, ZnO, ZrO2. A reasonable number of layers (〈20) not only enhances the optical performance of metallic reflectors, but also allows tuning said performance, which is not possible with classical mirrors relying on a single metal reflective layer. For instance, one can optimize the stack to reach a better performance than silver at typical mean incidence angles of solar light in CSP plants, for different locations. A solar mirror without rare or precious materials and more effective than traditional silver mirrors is thus obtained.

Potential and challenges of wind measurements using met-masts in complex topography for bridge design: Part I – Integral flow characteristics

The paper investigates the local topographic effect on the mean and integral flow characteristics recorded by sonic anemometers mounted on tall masts near the shoreline of three different Norwegian fjords. Two years of measurements are analysed, using data from 25 three-dimensional sonic anemometers mounted at heights from 12 ​m to 95 ​m above the ground. The goal is to explore the potential and challenges of using wind measurements from the masts located on the shores of the fjords in the design of planned bridge crossings. Therefore, the study explores the deviations of the mean and turbulent flow characteristics from the traditional case of flat and homogeneous terrain. Only records with mean wind speeds of 12 ​m ​s−1 and above at all elevations above the ground are considered due to their relevance in buffeting response, which led to the identification of a limited number of sectors representative of strong wind conditions. Mean incidence angles with absolute values above 6° and low mean wind shear are measured in several of the selected sectors. This highlights the major influence of the local terrain and vegetation around the masts on the wind conditions at the mast locations. Nevertheless, non-dimensional variance and covariance estimates of the velocity components are found to be consistent with values previously measured from bridge decks crossing narrow fjords. The paper explores also an alternative approach to compute the friction velocity, the estimation of which is challenging in a fjord-like topography. This first part of the paper focuses on integral flow characteristics, a second follow-on part will investigate in details which eddy wave-numbers are most affected by the local terrain, based on the analysis of the spectra of the velocity fluctuations.

Use of Sentinel-1 Multi-Configuration and Multi-Temporal Series for Monitoring Parameters of Winter Wheat

The present study aims to investigate the potential of multi-configuration Sentinel-1 (S-1) synthetic aperture radar (SAR) images for characterizing four wheat parameters: total fresh mass (TFM), total dry mass (TDM), plant heights (He), and water content (WC). Because they are almost independent on the weather conditions, we have chosen to use only SAR. Samples of wheat parameters were collected over seven fields (three irrigated and four rainfed fields) in Southwestern France. We first analyzed the temporal behaviors of wheat parameters (He, TDM, TFM and WC) between February and June 2016. Then, the temporal profiles of the S-1 backscattering coefficients (VV, VH), the difference (VH − VV), the sum of the polarizations (VH + VV) and their cumulative values are analyzed for two orbits (30 and 132) during the wheat-growing season (from January to July 2016). After that, S-1 signals were statistically compared with all crop parameters considering the impact of pass orbit, irrigation and two vegetative periods in order to identify the best S-1 configuration for estimating crop parameters. Interesting S-1 backscattering behaviors were observed with the various wheat parameters after separating irrigation impacts and vegetative periods. For the orbit 30 (mean incidence angle of 33.6°); results show that the best S-1 configurations (with coefficient of determination (R2) &gt; 0.7) were obtained using the VV and VH + VV as a function of the He, TDM and WC, over irrigated fields and during the second vegetative period. For the orbit 132 (mean incidence angle of 43.4°), the highest dynamic sensitivities (R2 &gt; 0.8) were observed for the VV and VH + VV configurations with He, TDM and TFM over irrigated fields during the first vegetative period. Overall, the sensitivity of S-1 data to wheat variables depended on the radar configuration (orbits and polarizations), the vegetative periods and was often better over irrigated fields in comparison with rainfed ones. Significant improvements of the determination coefficients were obtained when the cumulative (VH + VV) index was considered for He (R² &gt; 0.9), TDM (R² &gt; 0.9) and TFM (R² &gt; 0.75) for irrigated fields, all along the crop cycle. The estimate of WC was more limited (R² &gt; 0.6) and remained limited to the second period of the vegetation cycle (from flowering onwards). Whatever parameters were considered, the relative errors never exceeded 23%. This study has shown the importance of considering the agricultural practices (irrigation) and vegetative periods to effectively monitor some wheat parameters with S-1 data.

A three-variables cokriging method to estimate bare-surface soil moisture using multi-temporal, VV-polarization synthetic-aperture radar data

A cokriging model using three variables is developed to estimate bare-surface soil moisture content based on multi-temporal synthetic-aperture radar (SAR) data. This model utilizes cross-semivariogram function to take into account spatially varied correlation among multiple variables. Here, five sentinel-1 SAR scenes were acquired on different dates using the interferometric wide-swath (IW) mode and a mean incidence angle of 39.02° to build the backscatter temporal-ratio in VV polarization. This algorithm is generally based on the assumption of contributions of soil moisture and surface roughness to the backscattering coefficient under the given radar configurations. In this study, soil moisture is the target variable, and the surface roughness and backscatter temporal-ratio in VV polarization are the auxiliary variables. A cross-semivariogram relationship is formulated among those three spatial variables; then ordinary cokriging is used, based on that cross-semivariogram formula, to estimate the spatial distribution of bare soil moisture content. The root mean square error (RMSE) of soil-moisture retrieval ranges from 2.62 to 2.66 vol%. The new empirical model described in this paper will provide new insights into the study of soil environments.

Variation in the Anatomy of the Normal Human Optic Chiasm: An MRI Study.

Compression of the optic chiasm typically leads to bitemporal hemianopia. This implies that decussating nasal fibers are selectively affected, but the precise mechanism is unclear. Stress on nasal fibers has been investigated using finite element modeling but requires accurate anatomical data to generate a meaningful output. The precise shape of the chiasm is unclear: A recent photomicrographic study suggested that nasal fibers decussate paracentrally and run parallel to each other in the central arm of an "H." This study aimed to determine the population variation in chiasmal shape to inform future models. Sequential MRI scans of 68 healthy individuals were selected. 2D images of each chiasm were created and analyzed to determine the angle of elevation of the chiasm, the width of the chiasm, and the offset between the points of intersection of lines drawn down the centers of the optic nerves and contralateral optic tracts. The mean width of the chiasm was 12.0 ± 1.5 mm (SD), and the mean offset was 4.7 ± 1.4 mm generating a mean offset:width ratio of 0.38 ± 0.09. No chiasm had an offset of zero. The mean incident angle of optic nerves was 56 ± 7°, and for optic tracts, it was 51 ± 7°. The human optic chiasm is "H" shaped, not "X" shaped. The findings are consistent with nasal fibers decussating an average of 2.4 mm lateral to the midline before travelling in parallel across the midline. This information will inform future models of chiasmal compression.

Reducing the optical end losses of a linear Fresnel reflector using novel techniques

The objective of this work is the investigation of some alternative ideas for enhancing the optical performance of a linear Fresnel reflector (LFR) with North-South orientation. More specifically, the examined methods aim to reduce the optical end losses which are crucial for the short LFR plants in particular during the winter period. The first studied idea is the extension of the receiver after the concentrator which is able to enhance the yearly mean incident angle modifier up to 50.3%. The second examined idea is the displacement of the receiver in order to eliminate the non-illuminated area at the beginning of the receiver. This idea proved that the mean yearly incident angle modifier can be enhanced up it 20.2% for a displacement equal to 20% of the concentrator length. The third examined idea is the hybrid design with the extended and displayed receiver in combined. This idea leads to intermediates enhancements compared to the previous cases but its advantage is the lower investment cost compared to the simple receiver extension case. The analysis is performed with a developed optical model in SolidWorks Flow Simulation and the yearly evaluation has been done for the location of Athens (Greece).

An experimental study of trailing edge noise from a pitching airfoil.

In this study, the far-field noise from a pitching NACA 0012 airfoil was measured at a Reynolds number of 6.6 × 104. The pitching motion was in sinusoidal functions with a mean incident angle of 0°. Cases with the pitching amplitude varying from 7.5° to 15° and frequency from 3 to 8 Hz were tested, corresponding to the reduced frequency from 0.094 to 0.25. A microphone was placed in the far-field and the particle image velocimetry technique was utilized to study the flow structures near the trailing edge. The short-time Fourier transformation results of the noise signals revealed that a high-level narrow-band noise hump occurred at a specific angle of attack in a pitching cycle. At the corresponding moment, a coherent vortex street convecting on the airfoil surface was observed, and the vortex shedding frequency was in good agreement with the central frequency of the noise hump. The occurrence of the noise humps was attributed to the laminar boundary layer separation. In one pitching period, the moment when the narrow-band noise hump occurs is independent from the pitching amplitude and it is delayed as the pitching frequency increases. Larger pitching frequency or amplitude results in lower peak level of the noise humps.

Experimental and Numerical Study of the Unsteady Wake of a Supercritical Airfoil in a Compressible Flow

Experimental investigations were carried out to study the wake profile of a supercritical airfoil at Mach numbers of 0.4 and 0.6 in a pitching motion. Both static and dynamic tests were conducted in a tri-sonic wind tunnel. Flow field inside the wake was measured by hot wire anemometry at downstream distances of 0.25 and 0.5 times the chord length from trailing edge. All data were taken at mean incidence angle of 3°; the amplitude of oscillation was 3° and the oscillation frequencies were 3 and 6 Hz. Moreover, numerical study was applied for the same airfoil under similar experimental test conditions; finally, wake profiles obtained from both numerical and experimental methods were compared.

The effect of incidence angle on the reflectance of solar mirrors

Solar reflectors for Concentrating Solar Technologies require a high reflectance in the terrestrial solar spectrum (280–4000nm). Besides the wavelength, the reflectance of solar mirror materials is also dependent on the incidence angle of the incoming sunlight. The commonly used measurement equipment measures the reflectance at fixed near-normal incidence angles, typically between 8° and 15°. In this work, the annual incidence angle frequency distribution has been calculated for a LS3/Eurotrough-type parabolic-trough collector located at different sites, and for the heliostat field of the solar tower system CESA-1 located at the Plataforma Solar de Almería in Tabernas, southern Spain. It was found that the most frequent incidence angles registered in the solar field are quite higher than the ones at which reflectance is measured with state of the art instruments, obtaining mean incidence angles in the range of 28–35° depending on the type and location of the solar field.A methodology to predict the off-normal reflectance of silvered-glass mirrors based on near-normal reflectance and transmittance measurements of the uncoated glass is presented. The complex refractive index of 2, 4 and 5mm thick solar glass and the deposited silver was determined and used to model the solar weighted reflectance of silvered-glass mirrors at different incidence angles. The model was compared to experimental measurements. For this purpose, the Spectral Specular Reflectometer (S2R) has been improved and updated with a polarizer crystal to measure reflectance at perpendicular (s-pol) and parallel (p-pol) polarizations up to incidence angles of θ = 70°.Eight solar mirror materials (three silvered-glass mirrors of different glass thicknesses, two anti-soiling coated glass mirrors, two enhanced aluminum reflectors and a silvered polymer film) have been measured over a broad range of incidence angles and the results have been weighted with the annual incidence angle frequency distribution. The obtained incidence angle-weighted reflectance is a suited parameter to compare the efficiency of solar mirror materials taking into account their use in a specific collector type and location.

Free vibration numerical simulation technique for extracting flutter derivatives of bridge decks

A numerical simulation technique based on computational fluid dynamics (CFD) for determining the time-varying histories of free vibration displacements, velocities, and aerodynamic forces of bridge decks is presented. The weak coupling method is used to address the problem of fluid-structure-interaction (FSI). The flutter derivatives can be conveniently extracted using the numerically simulated displacements, velocities, and aerodynamic forces, which is similar to the procedure adopted in the forced vibration method. First, the identification accuracy of flutter derivatives is validated by comparison with the theoretical results for an ideal thin plate. Then, the flutter derivatives of two typical bridge deck sections, one streamlined and one bluff, are extracted by the proposed method. The results of the streamlined section show good agreement with other methods. However, for the bluff section, noticeable discrepancies exist between different methods. The mean angle of incidence in the free vibration method is shown to be responsible for these disagreements. The strengths of the newly-proposed approach are compared with those of the numerical and experimental forced vibration and experimental free vibration methods. This convenient and effective approach may serve as a building block for extracting flutter derivatives and better understanding of the aeroelastic responses of long-span flexible bridges.

Experimental and numerical investigation into the wake of a supercritical airfoil in a compressible unsteady flow

Experimental investigations were carried out to study the wake characteristics of a pitching supercritical airfoil at Mach number of 0.6. Flow field inside the wake was measured by a hot-wire anemometry at downstream distances from trailing edge of 0.25 and 0.5 times the chord length. All data were taken at mean incidence angles of 0 and 3°. The amplitudes of oscillation were 1 and 3° while the oscillation frequencies were 3 and 6 Hz. Output signals acquired from sensors were analyzed besides the effects of such parameters as frequency and oscillation amplitude. Moreover, a comprehensive numerical study was carried out for the same airfoil under similar experimental test conditions; then, the results of numerical simulations were analyzed and compared with those of experimental tests. Results of the present research could be summarized as: observation of hysteresis and how it is affected by frequency and amplitude variations, observation of increasing turbulence intensity by root mean square investigation and also increasing signal energy by means of power spectral density diagram for those sensors lied inside the wake, and finally, study of correlation between wake’s interior sensors and exterior ones.

Explanation of penetration depth variation during laser welding under variable ambient pressure

It has been observed that the penetration depth during laser welding (LW) under vacuum or reduced ambient pressure could be significantly greater than that during welding under atmospheric pressure. Previous explanations of this phenomenon usually limit to specific wavelength laser welding and have difficulties in explaining why the variation will disappear, as the welding speed increases. Here, we propose that this variation is caused by the temperature difference of keyhole wall under variable ambient pressure based on a correct physical description of related processes. A new surface pressure model, dependent on ambient pressure, is proposed for describing the evaporation process during laser material interaction under variable ambient pressure. For laser welding of a 304 stainless steel with 2.0 kW laser power and 3 m/min welding speed, it is shown that the average keyhole wall temperature is around 2900 K under atmospheric pressure, and only around 2300 K under vacuum, which results in significant penetration depth variations. Interestingly, it is also shown that as the welding speed increases, the average temperature of the front keyhole wall gradually rises due to the reduction of the mean incident angle of laser, and the magnitude of this increase is larger in welding under vacuum than under atmospheric pressure. It allows us to explain why the penetration depth improvement decreases to zero with the increase of welding speed.

Multiobjective Particle Swarm Optimization of Boresight Error and Transmission Loss for Airborne Radomes

The streamlined shapes of airborne radomes tend to cause severe degradation of the electromagnetic (EM) performance, which could be compensated by properly designing the thickness profile of the radome. Boresight error (BSE) and transmission loss (TL) are the two most important EM characteristics that need to be improved. Previous researches focused on the single-objective optimization of either BSE, or the linear combination of BSE and TL through the conventional weighted aggregation (CWA) method. However, the single-objective optimization is limited in reaching mutual balance between BSE and TL, and could not explain why the optimal solution obtained by optimizing BSE usually has a better TL than the constant thickness radomes. In this communication, the multiobjective particle swarm optimization (MOPSO) combined with 3-D ray-tracing method is employed to optimize the BSE and TL simultaneously for airborne radomes. The simulation results explain why the optimal solution on BSE usually has a better TL; the TL wall phenomenon in the multiobjective space is also explained. Both problems are due to the variation of mean incident angle of the radomes during antenna scanning, which is general for streamlined radomes. Significant conclusions are drawn and could benefit the radome design in engineering applications.

Numerical Simulation of Unsteady Aerodynamic Loads over an Aerofoil in Transonic Flow

The unsteady aerodynamic loads are the basic of the aeroelasitc. This paper focuses on the computation of the unsteady aerodynamic loads for forced periodic motions under high subsonic Mach numbers. The flow is modeled using the Euler equations and an unsteady time-domain solver is used for the computation of aerodynamic loads for forced periodic motions. The Euler equations are discretized on curvilinear multi-block body conforming girds using a cell-centred finite volume method. The implicit dual-time method proposed by Jameson is used for time-accurate calculations. Rigid body motions were treated by moving the mesh rigidly in response to the applied sinusoidal motion. For NACA 0012 airfoil, a validation of the unsteady aerodynamics loads is first considered. Furthermore, a study for understanding the influence of motion parameters, the Mach number, mean angle of incidence, reduced frequency, amplitude, was also conducted. A reverse of the trend of hysteretic loops can be observed with the increasing of the Mach number. Nonlinear hysteretic loops are turned up when increasing the amplitude and the reduced frequency during the applied pitch sinusoidal motion.

Unsteady Surface Pressures and Airload of a Pitching Airfoil

This paper presents unsteady surface pressure variations of a symmetrical NACA0012 section commonly used on Vertical-axis wind turbine blades. The section was tested at a Reynolds number of 90,000, mean incidence angles of<remove-image><remove-image> 15 and -15, and a reduced frequency of 0.20. The experimental results show that the airfoil motion had significant effects on surface pressure distribution over the airfoil, leading to a formation and shedding of an energetic leading edge vortex which strongly affects the overall airload over the incidence range.

The Coseismic Insar Measurements of 2008 Yutian Earthquake and Its Inversion for the Fault Slip

AbstractWe have obtained the coseismic deformation along line of sight of the 2008 Yutian earthquake, using PALSAR images and SAR interferometry technique. Based on these InSAR measurements and the constrained least square method, we studied the source parameters of this big normal event. Four schemes of inversion were constructed, with the emphasis on the effect to slip distribution inversion of the incidence angle and azimuth angle. Our inversion results show that the incidence angle has certain effect on the slip distribution, which means that a substitution of location‐dependent incidence angle with constant mean incidence angle will lose some useful slip distribution on fault plane. Our inversion also shows that the azimuth angle, however, has almost no obvious effect and it is an optimal choice to use the mean azimuth angle. Our most robust slip distribution can be obtained with the two parameters being location‐dependent. In our favored inversion scheme using location‐dependent angles for both, the maximum slip reaches 3.2 m. Slip is mainly confined to 0~14 km depth and no evidence of shallow slip deficit. The inverted seismic moment M0 is 3.3×1019 N·m, equivalent to an event of magnitude Mw7.0.

Evaluation of terrain effect on microwave radiometer measurement and its correction

We develop a new technique for terrain correction of coarse resolution satellite microwave radiometer measurements using the high-resolution digital elevation model (DEM). With the high-resolution DEM and a facet model, we first simulated the terrain influences that resulted from both effects of local incidence and polarization rotation (PR) on the microwave radiometer measurements at the different scales of the radiometer footprints. The emissivity signals of bare surfaces are more sensitive on incidence and PR than vegetated surfaces. So the emissivities at different incidence angles of the bare surface generated by the advanced integral equation model (AIEM) were used to simulate the terrain effects on the satellite measurements. It was found that (1) the PR effect at the satellite footprint can be corrected using the absolute mean PR angle from all facets within the footprint, and (2) the satellite measurements can be described as from a mean incidence angle. Both angles can be obtained from all facets within the footprint with the high-resolution DEM and the satellite viewing geometry. Therefore, a corresponding terrain-correction technique was developed for satellite brightness temperature measurements. We also demonstrate the terrain effects on the satellite measurements from the advanced microwave scanning radiometer–earth observing system (EOS) (AMSR-E).