Large Field-of-View Interferometers for Environmental Sensing

The interferometer -spectrometer is an exceptionally powerful instrument for remotely sensing optical emission spectra associated with the environment. However, when a conventional Michelson interferometer is operated at high spectral resolution, a very narrow viewing field results. For the sensing of emissions which have a significant spatial distribution, which is often the case for environmental species, optical compensation can be employed to open up the field of view. The resulting reduction in observation time for the compensated relative to the uncompensated interferometer is R284/4. For a practical instrument using prism -type compensator elements, the viewing field can be extended to more than ten degrees full angle. Consequently, the observation time required to obtain a spectrum is reduced by more than two orders of magnitude

A Light Source for Testing CMOS Imagers

Testing the optical properties of complementary metal oxide (CMOS) imagers requires a light source. The light source must produce stable uniform light with calibrated wavelength and intensity. Available commercial light source units are costly and often unalterable to a custom test setup. The proposed light source is designed to be affordable and adaptable while maintaining the necessary optical quality. The design consists of an array of light emitting diodes (LED), an infrared (IR) cut-off filter, and holographic diffusers-all of which are encased in an anodized aluminum housing. Initial experimental results have shown that the light source has lasting stability and a light uniformity above 90 percent. Applications for this light source include the experimentation and testing of imagers, photo cells, and other optoelectronic devices

Small Rocket Measurements / Validation in Support of SABER

Small rocket measurements in the Mesosphere and lower Thermosphere / Ionosphere will serve to validate and improve measurements being made by the TIMED satellite\u27s SABER instrument. This validation can be made more cost effective and versatile by developing a smaller, lighter, and less expensive radiometer module. Recent developments in technology have allowed us to proceed in developing this smaller, more lightweight radiometric instrument We are currently working on a miniature 2-channel radiometer that will interface with a Viper DART sounding rocket payload, Along with its support circuitry and housing, we estimate the 2-channel radiometer to weigh less than 1 1/2 lbs and be less than 8 inches long with a 2 1/8 diameter, In this report we will discuss the development of this instrument, termed MINRAD, and our current standing

Conceptual design study for Infrared Limb Experiment (IRLE)

The phase A engineering design study for the Infrared Limb Experiment (IRLE) instrument, the infrared portion of the Mesosphere-Lower Thermosphere Explorer (MELTER) satellite payload is given. The IRLE instrument is a satellite instrument, based on the heritage of the Limb Infrared Monitor of the Stratosphere (LIMS) program, that will make global measurements of O3, CO2, NO, NO2, H2O, and OH from earth limb emissions. These measurements will be used to provide improved understanding of the photochemistry, radiation, dynamics, energetics, and transport phenomena in the lower thermosphere, mesosphere, and stratosphere. The IRLE instrument is the infrared portion of the MELTER satellite payload. MELTER is being proposed to NASA Goddard by a consortium consisting of the University of Michigan, University of Colorado and NASA Langley. It is proposed that the Space Dynamics Laboratory at Utah State University (SDL/USU) build the IRLE instrument for NASA Langley. MELTER is scheduled for launch in November 1994 into a sun-synchronous, 650-km circular orbit with an inclination angle of 97.8 deg and an ascending node at 3:00 p.m. local time

Comparison of SABER OH Measurements to Rocket Photometry Data

In 2002, the Sounding of the Atmosphere us- ing Broadband Emission Radiometry (SABER) instru- ment aboard the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite went online and has since been providing radiometric data concern- ing the mesosphere and lower thermosphere/ionosphere (MLTI) region of the atmosphere. Researchers at the Utah State University NASA Space Grant Consortium have been tasked with validating measurements of the hydroxyl airglow volume emission rates (VER) taken by SABER. To this end, we compare SABER measurements of the altitude distribution of hydroxyl airglow to mea- surements taken by photometers aboard rockets launched between 1961 and 1986 that were catalogued in 1988 by Baker and Stair [1]. We select for comparison SABER scans taken near these launch sites at the same time of year, and at similar solar zenith angles. We then plot the selected SABER altitude profiles alongside renormalized rocket photometer profiles. Important considerations for comparison are the mean thickness of emission layers, the mean altitude of their centers, and relative numbers of bifurcated airglow emission layers, which manifest as altitude profiles with two or more peaks

Optimization of Detector-Preamplifier for Cryogenic Spectrometry

The design optimization of the detector-preamplifier subsystem is critical to the achievement of sensitive infrared spectrometers. The application illustrated is for cryogenically- cooled detectors, but the optimal approach based upon an operational preamplifier is general for detector operation under background limited conditions

Recombinations to the Rydberg States of Hydrogen and Their Effect During the Cosmological Recombination Epoch

In this paper we discuss the effect of recombinations to highly excited states (n > 100) in hydrogen during the cosmological recombination epoch. For this purpose, we developed a new ODE solver for the recombination problem, based on an implicit Gear's method. This solver allows us to include up to 350 l-resolved shells or ~61 000 separate levels in the hydrogen model and to solve the recombination problem for one cosmology in ~27 hours. This is a huge improvement in performance over our previous recombination code, for which a 100-shell computation (5050 separate states) already required ~150 hours on a single processor. We show that for 350 shells down to redshift z ~200 the results for the free electron fraction have practically converged. The final modification in the free electron fraction at z ~200 decreases from about \DeltaNe/Ne ~2.8% for 100 shells to \DeltaNe/Ne ~1.6% for 350 shells. However, the associated changes in the CMB power spectra at large multipoles l are rather small, so that for accurate computations in connection with the analysis of Planck data already ~100 shells are expected to be sufficient. Nevertheless, the total value of \tau could still be affected at a significant level. We also briefly investigate the effect of collisions on the recombination dynamics. With our current estimates for the collisional rates we find a correction of \DeltaNe/Ne ~ -0.088% at z ~ 700, which is mainly caused by l-changing collisions with protons. Furthermore, we present results on the cosmological recombination spectrum, showing that at low frequencies collisional processes are important. However, the current accuracy of collisional rates is insufficient for precise computations of templates for the recombination spectrum at \nu<~1 GHz, and also the effect of collisions on the recombination dynamics suffers from the uncertainty in these rates.Comment: 14 pages, 11 figures, 1 table; Sect. 4.1.2 added; accepted versio

Response of Continuous Maize with Stover Removal to Living Mulches

Constraints to maize (Zea mays L.) stover biomass harvest may be mitigated by using a living mulch (LM) to offset C exports and control soil erosion. Living mulches can compete with the main crop for resources. The objective of this research was to quantify competitive effects of LM management systems grown in continuous maize with stover removal. Maize was planted into creeping red fescue (CF) (Festuca rubra L.), Kentucky bluegrass (KB) (Poa pratensis L.), and a mixture of CF and white clover (Trifolium repens L.) (MX) LMs in 2008, 2009, and 2010 near Ames, IA. Management treatments were fall strip-tillage (ST) and no-tillage (NT), with either a pre-planting paraquat burn-down followed by two glyphosate bands (PQ) or glyphosate bands only (GLY). Kentucky bluegrass PQ ST produced similar grain yields (11,230 kg ha−1) all 3 yr as the no LM control (11,810 kg ha−1) with a harvest index (HI) of 0.55 compared to 0.52 in the control, averaged across years. The control produced greater stover dry matter (SDM) (10,110 kg ha−1) 2 of the 3 yr compared to KB PQ ST (8600 kg ha−1). Total groundcover averaged 80% in KB PQ ST compared to only 45% in the no LM control. These results indicate that a combination of herbicide suppression and ST suppresses LMs adequately to maintain competitive maize grain yields. Additional research under varying climatic conditions will further quantify the risk of LM management systems to increase the sustainable stover harvest of maize biomass feedstocks

Investigation of Testosterone, Androstenone, and Estradiol Metabolism in HepG2 Cells and Primary Culture Pig Hepatocytes and Their Effects on 17βHSD7 Gene Expression

Steroid metabolism is important in various species. The accumulation of androgen metabolite, androstenone, in pig adipose tissue is negatively associated with pork flavor, odour and makes the meat unfit for human consumption. The 17β-hydroxysteroid dehydrogenase type 7 (17βHSD7) expressed abundantly in porcine liver, and it was previously suggested to be associated with androstenone levels. Understanding the enzymes and metabolic pathways responsible for androstenone as well as other steroids metabolism is important for improving the meat quality. At the same time, metabolism of steroids is known to be species- and tissue-specific. Therefore it is important to investigate between-species variations in the hepatic steroid metabolism and to elucidate the role of 17βHSD7 in this process. Here we used an effective methodological approach, liquid chromatography coupled with mass spectrometry, to investigate species-specific metabolism of androstenone, testosterone and beta-estradiol in HepG2 cell line, and pig cultured hepatocytes. Species- and concentration-depended effect of steroids on 17βHSD7 gene expression was also investigated. It was demonstrated that the investigated steroids can regulate the 17βHSD7 gene expression in HepG2 and primary cultured porcine hepatocytes in a concentration-dependent and species-dependent pattern. Investigation of steroid metabolites demonstrated that androstenone formed a 3′-hydroxy compound 3β-hydroxy-5α-androst-16-ene. Testosterone was metabolized to 4-androstene-3,17-dione. Estrone was found as the metabolite for β-estradiol. Inhibition study with 17βHSD inhibitor apigenin showed that apigenin didn't affect androstenone metabolism. Apigenin at high concentration (50 μM) tends to inhibit testosterone metabolism but this inhibition effect was negligible. Beta-estradiol metabolism was notably inhibited with apigenin at high concentration. The study also established that the level of testosterone and β-estradiol metabolites was markedly increased after co-incubation with high concentration of apigenin. This study established that 17βHSD7 is not the key enzyme responsible for androstenone and testosterone metabolism in porcine liver cells. © 2012 Chen et al