7,800 research outputs found
Computer assisted interactive resource scheduling system
A computer system is reported that effectively schedules complex mission support by processing spacecraft requirements, station capabilities, and ephemeris data in teletype format ready for transmission
Station-keeping guidance
The station-keeping guidance system is described, which is designed to automatically keep one orbiting vehicle within a prescribed zone fixed with respect to another orbiting vehicle. The active vehicle, i.e. the one performing the station-keeping maneuvers, is referred to as the shuttle. The other passive orbiting vehicle is denoted as the workshop. The passive vehicle is assumed to be in a low-eccentricity near-earth orbit. The primary navigation sensor considered is a gimballed tracking radar located on board the shuttle. It provides data on relative range and range rate between the two vehicles. Also measured are the shaft and trunnion axes gimbal angles. An inertial measurement unit (IMU) is provided on board the orbiter. The IMU is used at all times to provide an attitude reference for the vehicle. The IMU accelerometers are used periodically to monitor the velocity-correction burns applied to the shuttle during the station-keeping mode. The guidance system is capable of station-keeping the shuttle in any arbitrary position with respect to the workshop by periodically applying velocity-correction pulses to the shuttle
Economic Analysis of Using Soybean Meal as a Mushroom Growing Substrate
Mushrooms have been grown commercially on many different substrates for years, usually agricultural by-products such as straw or stover. Increased popularity for specialty mushrooms with consumers has led to increased production and great demand for economic substrates. Oyster mushrooms are easier to grow relative to other types of mushrooms and their production has increased dramatically in recent years. This study examines the economic feasibility of using soybean hulls as a primary substrate for oyster mushrooms, replacing traditional wheat straw. The study uses a cost-benefit analysis to determine an optimal substrate based on yield and the number of crops harvested per year. The study shows that soybean hulls, combined with corn gluten or soybean meal increases yield 4.5 times, which more than offsets for higher costs for soybean hulls. The use of soybean substrate also allows a producer to raise about four more crops per year, which in turn uses fixed resources more efficiently and increases profitability.Oyster, Mushrooms, Substrate, Soybean, Hulls, Meal, Economic, Feasibility, Crop Production/Industries,
Apparatus for measuring thermal conductivity Patent
Development of apparatus for measuring thermal conductivit
Design, fabrication, and test of a composite material wind turbine rotor blade
The aerodynamic design, structural design, fabrication, and structural testing is described for a 60 foot long filament wound, fiberglass/epoxy resin matrix wind turbine rotor blade for a 125 foot diameter, 100 kW wind energy conversion system. One blade was fabricated which met all aerodynamic shape requirements and was structurally capable of operating under all specified design conditions. The feasibility of filament winding large rotor blades was demonstrated
Recommended from our members
Net solar generation potential from urban rooftops in Los Angeles
Rooftops provide accessible locations for solar energy installations. While rooftop solar arrays can offset in-building electricity needs, they may also stress electric grid operations. Here we present an analysis of net electricity generation potential from distributed rooftop solar in Los Angeles. We integrate spatial and temporal data for property-level electricity demands, rooftop solar generation potential, and grid capacity constraints to estimate the potential for solar to meet on-site demands and supply net exports to the electric grid. In the study area with 1.2 million parcels, rooftop solar could meet 7200 Gigawatt Hours (GWh) of on-site building demands (~29% of demand). Overall potential net generation is negative, meaning buildings use more electricity than they can produce. Yet, cumulative net export potential from solar to grid circuits is 16,400 GWh. Current policies that regulate solar array interconnection to the grid result in unutilized solar power output of 1700 MW. Lower-income and at-risk communities in LA have greater potential for exporting net solar generation to the grid. This potential should be recognized through investments and policy innovations. The method demonstrates the need for considering time-dependent calculations of net solar potential and offers a template for distributed renewable energy planning in cities
Model of Thermal Wavefront Distortion in Interferometric Gravitational-Wave Detectors I: Thermal Focusing
We develop a steady-state analytical and numerical model of the optical
response of power-recycled Fabry-Perot Michelson laser gravitational-wave
detectors to thermal focusing in optical substrates. We assume that the thermal
distortions are small enough that we can represent the unperturbed intracavity
field anywhere in the detector as a linear combination of basis functions
related to the eigenmodes of one of the Fabry-Perot arm cavities, and we take
great care to preserve numerically the nearly ideal longitudinal phase
resonance conditions that would otherwise be provided by an external
servo-locking control system. We have included the effects of nonlinear thermal
focusing due to power absorption in both the substrates and coatings of the
mirrors and beamsplitter, the effects of a finite mismatch between the
curvatures of the laser wavefront and the mirror surface, and the diffraction
by the mirror aperture at each instance of reflection and transmission. We
demonstrate a detailed numerical example of this model using the MATLAB program
Melody for the initial LIGO detector in the Hermite-Gauss basis, and compare
the resulting computations of intracavity fields in two special cases with
those of a fast Fourier transform field propagation model. Additional
systematic perturbations (e.g., mirror tilt, thermoelastic surface
deformations, and other optical imperfections) can be included easily by
incorporating the appropriate operators into the transfer matrices describing
reflection and transmission for the mirrors and beamsplitter.Comment: 24 pages, 22 figures. Submitted to JOSA
Geometric Scaling and QCD Dynamics in DIS
DIS data from HERA show a striking regularity as \sigma^{\gamma^* p} is a
function of the ratio \tau=Q^2/Q_s^2(x) only. The scaling function shows a
break at \tau ~ 1, which has been taken as an indication for saturation.
However, besides saturation also the transition between dominance of
k_t-ordered (DGLAP) and k_t-non-ordered (BFKL) evolution contributes to a break
around this value of \tau, as well as the suppression for small Q^2 due to
finite quark masses and confinement. In this paper we use a dipole cascade
model based on Mueller's dipole model, which also includes energy conservation
and pomeron mergins, to investigate the contributions of these different
effects to the scaling behaviour. As a result we predict that the scaling
function for \tau 1 GeV^2 become
available. We also investigate the scaling properties of the charm contribution
and the impact parameter dependence of the saturation scale.Comment: references added, figures 2, 7 and 8 updated v3: reference added,
some misprints correcte
USING CHOICE EXPERIMENTS TO ELICIT FARMERS PREFERENCES? FOR CROP AND HEALTH INSURANCE
A random utility discrete choice experiments is used to determine farmers' preferences for health insurance, crop insurance, and a product that switches some portion of crop insurance subsidy to health insurance premium subsidy with access to large-pool risk groups.Risk and Uncertainty,
Spatial and temporal filtering of a 10-W Nd:YAG laser with a Fabry-Perot ring-cavity premode cleaner
We report on the use of a fixed-spacer Fabry–Perot ring cavity to filter spatially and temporally a 10-W laser-diode-pumped Nd:YAG master-oscillator power amplifier. The spatial filtering leads to a 7.6-W TEMinfinity beam with 0.1% higher-order transverse mode content. The temporal filtering reduces the relative power fluctuations at 10 MHz to 2.8 x 10^-/sqrtHz, which is 1 dB above the shot-noise limit for 50 mA of detected photocurrent
- …
