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Large Field-of-View KD*P Modulator for Solar Polarization Measurements
This paper will describe the evolution of the Marshall Space Flight Center electro-optical polarimeter with emphasis on the field of view characteristics of the its KD*P modulator. Understanding the field of view characteristics was essential to the success of the MSFC vector magnetograph. The paper will show how the field of view errors of KD*P look similar to the polarization patterns seen in simple sunspots and why the placement of the KD*P in a collimated beam was essential in separating the instrumental polarization from the solar signal. Finally, this paper will describe a modulator design which minimizes those field-of-view errors.
Large Field-of-view KD*P Modulator for Solar Polarization Measurements
This paper will describe the evolution of the Marshall Space Flight Center electro-optical polarimeter with emphasis on the field of view characteristics of the its KD*P modulator. Understanding the field of view characteristics was essential to the success of the MSFC vector magnetograph. The paper will show how the field of view errors of KD*P look similar to the polarization patterns seen in simple sunspots and why the placement of the KD*P in a collimated beam was essential in separating the instrumental polarization from the solar signal. Finally, this paper will describe a modulator design which minimizes those field-of-view errors and will used in the new magnetograph development program at the University of Alabama, Huntsville.
Using KD(asterisk)P modulators for polarization measurements of the sun
Longitudinal KD(asterisk)Ps are used in ground-based solar magnetographs to eliminate seeing effects by rapidly changing their retardation characteristics. Although one of the main applications for longitudinal KD(asteriak)Ps has been their use as a variable retarder for 'imaging' applications, an understanding of their limitations is important when developing scientific instruments that make very accurate polarization measurements. This paper discusses some of the problems associated with the use of these devices in the Marshall Space Flight Center (MSFC) vector magnetograph, including temperature, field of view errors, and electrical characteristics.
Optical properties of KD*P modulators
Longitudinal KD*P modulators are used in ground-based solar magnetographs to eliminate seeing effects. Although the modulators can be used as variable retarders, the optical properties when zero voltage is applied influences the performance on instruments requiring very accurate polarization measurements. Measurements at the Marshall Space Flight Center are discussed in terms of the optical properties of KD*P modulators when zero voltage is applied. The measurements can be used to predict the modulation characteristics of the devices and to determine the polarization accuracy that can be expected from the vector magnetograph.
Development of a large field-of-view KD potassium di-deuterium phosphate modulator: Center Director's Discretionary Fund
Magnetographs, which measure polarized light, allow solar astronomers to infer the magnetic field intensity on the Sun. The Marshall Space Flight Center (MSFC) Vector Magnetograph is such an imaging instrument. The instrument requires rapid modulation between polarization states to minimize seeing effects. The accuracy of those polarization measurements is dependent on stable modulators with small field-of-view errors. Although these devices are very important in ground-based telescopes, extending the field of view of electro-optical crystals such as KD*Ps (potassium di-deuterium phosphate) could encourage the development of these devices for other imaging applications. The work that was done at MSFC as part of the Center Director's Discretionary Fund (CDDF) to reduce the field-of-view errors of instruments that use KD*P modulators in their polarimeters is described.
DC bias modulation characteristics of longitudinal KD*P modulators
A test program designed to study the DC modulation characteristics of longitudinal KD*P modulators and to determine what electrode structure might improve the performance of these devices is presented which was developed in the Marshall Space Flight Center. The physical constraints of these devices and the necessary electrical characteristics that the KD*P modulators must have to be used in the MSFC polarimeter are discussed.
200-IA-1 Operable Unit Human Health Risk and Kd Screen
The purpose of this environmental calculation file (ECF) is to provide the following: Document the data processing and data reduction steps taken to prepare the 200-IA-1 Operable Unit (OU) data set that will be used to calculate the sample-specific screening level human health risk evaluation; Document the data processing and data reduction steps taken to prepare the 200-IA-1 OU data set that will be used to identify analytes that could potentially impact groundwater in the future beneath the 200-IA-1 OU representative waste sites; Document the assumptions, equations, and methodologies used to calculate the screening levels for human health cancer risks and noncancer hazards for each representative waste site assigned to the 200-IA-1 OU. Individual measured soil concentrations from 0 to 4.6 m (15 ft) below ground surface (bgs) (shallow vadose zone) are used to calculate the total excess lifetime cancer risk (ELCR) and hazard index (HI) for the outdoor worker scenario to determine if there is a basis for remedial action. Individual measured soil concentrations from the ground surface to the groundwater table are used for the distribution coefficient (Kd) screen to identify analytes that could potentially impact groundwater in the future beneath the 200-IA-1 OU representative waste sites. This ECF supports DOE/RL-2020-51, 200-IA-1 OU Focused Feasibility Study, under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). A risk characterization based upon the evaluation of the health risk estimates developed in this ECF will be presented in the focused feasibility study report.
Glycosyl residue composition of cell wall extracts from tillers of switchgrass WT and PvGAUT4-KD plants
Glycosyl residue composition of cell wall extracts from tillers of switchgrass WT and PvGAUT4-KD plants
Glycosyl residue composition and total carbohydrate in cell wall extracts from WT and PvGAUT4-KD lines
Glycosyl residue composition and total carbohydrate in cell wall extracts from WT and PvGAUT4-KD lines
Glycosyl residue composition of cell wall extracts from stems of P. deltoides WT, vector control and PdGAUT4-KD plants
Glycosyl residue composition of cell wall extracts from stems of P. deltoides WT, vector control and PdGAUT4-KD plants
Glycosyl residue composition and total carbohydrate of cell wall extracts from WT and PdGAUT4-KD lines
Glycosyl residue composition and total carbohydrate of cell wall extracts from WT and PdGAUT4-KD lines
Glycosyl linkage analysis of fractionated cell walls from switchgrass WT and PvGAUT4-KD lines
Glycosyl linkage analysis of fractionated cell walls from switchgrass WT and PvGAUT4-KD lines
Glycosyl linkage analysis of fractionated cell walls from P.deltoides WT and PdGAUT4-KD lines.
Glycosyl linkage analysis of fractionated cell walls from P.deltoides WT and PdGAUT4-KD lines.
Large field-of-view KD*P modulator
This paper describes how FOV errors have affected the polarization measurements of the NASA Marshall vector magnetograph and how a polarimeter has been modified to minimize these errors. The design of a large-FOV (LFOV) KD*P modulator is discussed. The Poincare sphere is used to visualize the function of the different optical elements that make up the LFOV modulator.
Blade Motion and Bouncing Tests of KD-1 Autogiro
There are forwarded herewith the results of blade motion and bouncing tests on the Kellett KD-1 three-bladed autogiro. Motion picture records and two-component accelerometer records were taken in flight during glides at air speeds from 30 miles per hour to 100 miles per hour indicator readings. Calibration curves of correct indicated air speed and rotor speed as functions of air speed meter reading were established with a trailing pitot-static head and a rotoscope, at 2,000 ft. altitude and an air density of 0.00231 slug/ cu. ft., all tests being made at approximately that density.