4,161 research outputs found
An Economic Analysis of Fluid Milk Processing in Alaska
Alaskan fluid milk is processed for market by a two-firm industry.
In Delta Junction, the Northern Lights Dairy obtains milk from two
producers and services an Interior market from Delta to Fairbanks. In
Anchorage , Matanuska Maid (M-M) obtains milk from II producers
and markets its products largely in southcentral Alaska and , to a less
extent, in Fairbanks. Direct competition between the two is minimal.
The principal source of competition is preprocessed fluid milk shipped
in from Puget Sound
Solar array flight dynamic experiment
The purpose of the Solar Array Flight Dynamic Experiment (SAFDE) is to demonstrate the feasibility of on-orbit measurement and ground processing of large space structures' dynamic characteristics. Test definition or verification provides the dynamic characteristic accuracy required for control systems use. An illumination/measurement system was developed to fly on space shuttle flight STS-41D. The system was designed to dynamically evaluate a large solar array called the Solar Array Flight Experiment (SAFE) that had been scheduled for this flight. The SAFDE system consisted of a set of laser diode illuminators, retroreflective targets, an intelligent star tracker receiver and the associated equipment to power, condition, and record the results. In six tests on STS-41D, data was successfully acquired from 18 retroreflector targets and ground processed, post flight, to define the solar array's dynamic characteristic. The flight experiment proved the viability of on-orbit test definition of large space structures dynamic characteristics. Future large space structures controllability should be greatly enhanced by this capability
An investigation into the probabilistic combination of quasi-static and random accelerations
The development of design load factors are investigated for aerospace and aircraft components and experiment support structures, which are subject to a simultaneous vehicle dynamic vibration and acoustically generated random vibration. The characteristics of the combined acceleration probability density function is determined, and an appropriate percentile level for the combined acceleration is selected. This mechanism is developed and graphical data is provided to select combined accelerations for most popular percentile levels
Solar array flight dynamic experiment
The purpose of the Solar Array Flight Dynamic Experiment (SAFDE) is to demonstrate the feasibility of on-orbit measurement and ground processing of large space structures dynamic characteristics. Test definition or verification provides the dynamic characteristic accuracy required for control systems use. An illumination/measurement system was developed to fly on space shuttle flight STS-31D. The system was designed to dynamically evaluate a large solar array called the Solar Array Flight Experiment (SAFE) that had been scheduled for this flight. The SAFDE system consisted of a set of laser diode illuminators, retroreflective targets, an intelligent star tracker receiver and the associated equipment to power, condition, and record the results. In six tests on STS-41D, data was successfully acquired from 18 retroreflector targets and ground processed, post flight, to define the solar array's dynamic characteristic. The flight experiment proved the viability of on-orbit test definition of large space structures dynamic characteristics. Future large space structures controllability should be greatly enhanced by this capability
A review of internal combustion engine combustion chamber process studies at NASA Lewis Research Center
The performance of internal combustion stratified-charge engines is highly dependent on the in-cylinder fuel-air mixing processes occurring in these engines. Current research concerning the in-cylinder airflow characteristics of rotary and piston engines is presented. Results showing the output of multidimensional models, laser velocimetry measurements and the application of a holographic optical element are described. Models which simulate the four-stroke cycle and seal dynamics of rotary engines are also discussed
Fracture of disordered solids in compression as a critical phenomenon: III. Analysis of the localization transition
The properties of the Hamiltonian developed in Paper II are studied showing
that at a particular strain level a ``localization'' phase transition occurs
characterized by the emergence of conjugate bands of coherently oriented
cracks. The functional integration that yields the partition function is then
performed analytically using an approximation that employs only a subset of
states in the functional neighborhood surrounding the most probable states.
Such integration establishes the free energy of the system, and upon taking the
derivatives of the free energy, the localization transition is shown to be
continuous and to be distinct from peak stress. When the bulk modulus of the
grain material is large, localization always occurs in the softening regime
following peak stress, while for sufficiently small bulk moduli and at
sufficiently low confining pressure, the localization occurs in the hardening
regime prior to peak stress.
In the approach to localization, the stress-strain relation for the whole
rock remains analytic, as is observed both in experimental data and in simpler
models.
The correlation function of the crack fields is also obtained. It has a
correlation length characterizing the aspect ratio of the crack clusters that
diverges as (\xi \sim (\ep_{c}-\ep)^{-2}) at localization.Comment: 11 pages, 3 figure
A Survey of Shock and Vibration Environments in the Four Major Modes of Transportation
No abstract availabl
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