15,594 research outputs found
Investigations leading to the development of a primary zinc-silver oxide battery of improved performance characteristics progress report no. 11, 1 may - 31 may 1964
Zinc-silver oxide battery design for improved and activated charge retention, voltage control, and temperature stabilit
An 11-meter deployable truss for the SEASAT radar antenna
A folding three dimensional truss and tripod assembly which deploys the SEASAT Synthetic Aperture Radar Antenna is described. The folding structure with the antenna panels and rf components stows in an 8.5-inch-thick package. Upon deployment, the structure produced is a flat and rigid support for the antenna
Hydrogeochemistry of the Caribou-Poker Creeks Research Watershed
Bedrock of the Caribou-Poker Creeks Research Watershed dissolves incongruently
with a first-order rate constant of about 5 x 10-6 day-1 at 5° C. The
resulting solution is potassium-calcium-magnesium rich. The soil-plant environment
acts on this solution through sorption of potassium and by evapotranspiration
to yield a solution that is relatively depleted in potassium and
enriched in calcium and magnesium, but with the same molar ratio of Ca:Mg as
the fluid from the rock dissolution. This fluid from the soil-plant reservoir
is the dominant contributor of ions to stream waters.
Using the discriminant functions obtained by multiple discriminant
analysis
DPKR = 0.572Si02 + 0.240Ca + 2.89Mg - 0.384Na + 0.452N03 - 9.18
DCRB = 0.913Si02 + 0.042Ca + 1.28Mg + 1.17Na + 4.63N03 - 7.27,
the waters of Caribou Creek and Poker Creek can be distinguished on the basis
of chemical composition. In general, Poker Creek waters are slightly more
concentrated than Caribou Creek waters.
On the average, 1.4 x 10^13g H20/year leaves the watershed as surface
water. At an average calcium concentration of 14 ppm for the water, 0.1% for
the bedrock, and a watershed area of 46 mi^2, this flow corresponds to a maximum
loss of about 17 metric tons of rock per hectare per year
Geology and Geochemistry of the Ship Creek and Monashka Creek reservoirs, Southcentral Alaska
Graywacke from the Ship Creek watershed, dissolves incongruently in distilled water. The dissolution appears to follow a first-order rate law which in integrated form is:
k = -2.303/t log No-Q/No
where No is the concentration in ppm of Ca, Mg, Na or K in the graywacke,
Q is the total quantity of these ions leached in time t(days), k is the rate constant in days-1. Experimentally derived rate constants for the dissolution of graywacke in distilled water at 5oC are log k+2CA, -4.128 day-1; log k+2Mg, -6.174 day-1; log k+Na, -5.800 day-1; and log k+K, -5.249 day-1. The above constants are for 40 to +100 mesh graywacke. A surface area correction term must be inserted in the above equation if it is applied to a different size fraction.
Using the above equation and rate constants, the chemical composition of a water in contact with graywacke was calculated. With the exception of magnesium, the agreement between the calculated composition and that of Ship Creek water was good. Assuming that the groundwater in the Ship Creek
watershed contacts about 1.5X104cm2 graywacke per liter, 120 to 360 days
are required at 5oC to produce the concentration of ions observed in Ship
Creek.
Release of exchangeable H+ from the soil mat to the reservoir water will not significant1y lower the pH of the water.
Leaching of heavy metals from sulfides contained in the bedrock of
the two watersheds does not pose a water quality hazard.
Lineaments in the bedrock at Monashka Creek may provide channels through which water may seep from the reservoir. These are not expected to pose a problem in retaining water in the reservoir, but they may result in small, new springs down grade from the reservoir.The work upon which this report is based was supported by funds provided
by the United States Department of the Interior, Office of Water
Resources Research and Technology, as authorized by the Water Resources
Research Act of 1964, Public Law 88-379, as amended. (Project A-045-ALAS
Cost analysis of new and retrofit hot-air type solar assisted heating systems
A detailed cost analysis/cost improvement study was performed on two Department of Energy/National Aeronautics and Space Administration operational test sites to determine actual costs and potential cost improvements of new and retrofit hot air type, solar assisted heating and hot water systems for single family sized structures. This analysis concentrated on the first cost of a system which included procurement, installation, and integration of a solar assisted heating and hot water system on a new or retrofit basis; it also provided several cost projections which can be used as inputs to payback analyses, depending upon the degree of optimism or future improvements assumed. Cost definitions were developed for five categories of cost, and preliminary estimates were developed for each. The costing methodology, approach, and results together with several candidate low cost designs are described
Automated Real-Time Testing (ARTT) for Embedded Control Systems (ECS)
Developing real-time automated test systems for embedded control systems has
been a real problem. Some engineers and scientists have used customized
software and hardware as a solution, which can be very expensive and time
consuming to develop. We have discovered how to integrate a suite of
commercially available off-the-shelf software tools and hardware to develop a
scalable test platform that is capable of performing complete black-box testing
for a dual-channel real-time Embedded-PLC-based control system
(www.aps.anl.gov). We will discuss how the Vali/Test Pro testing methodology
was implemented to structure testing for a personnel safety system with large
quantities of requirements and test cases.
This work was supported by the U.S. Department of Energy, Basic Energy
Sciences, under Contract No. W-31-109-Eng-38.Comment: 6 pages, 8 figures, ICALEPCS 2001, Poster Sessio
Arsenic in the Water, Soil Bedrock, and Plants of the Ester Dome Area of Alaska
Concentrations of arsenic as large as 10 ppm (200 times the safe
limit for drinking water) occur in the groundwater of a mineralized
residential area near Fairbanks. Bedrock of the area contains 750 ppm
As, primarily as arsenopyrite and scorodite. The oxygen-poor groundwater
is enriched in As(III) and ferrous iron while the surface waters
are iron free and contain less than 50 ppb As(V). Arsenic is removed
from the water by coprecipitation with ferric hydroxide. Some iron-rich
stream sediments contain as much as 1,400 ppm arsenic.
The distribution of arsenic in the groundwater is controlled by the
distribution of arsenic in the bedrock. The arsenic content of the B soil
horizon over mineralized veins is about 150 ppm, while that over barren
rock is 30 ppm. The vegetation over the veins is not significantly
enriched in arsenic.
Lettuce, radishes and tomatoes grown with arsenic-rich water (5 ppm) contain 16, 8 and 1 ppm As, respectively; these amounts are significantly
greater than plants not treated with arsenic.
Preliminary studies by state and federal health agencies show no
detrimental effects on the health of persons drinking these arsenic-rich
waters.The work upon which this publication is based was supported in part by
funds provided by the Office of Water Research and Technology (Project
B-037-ALAS, Agreement No. 14-34-0001-8056), U.S. Department of the
Interior, Washington, D.C., as authorized by the Water Research and
Development Act of 1978
How are Elementary Teachers Utilizing Technology to Enhance Their Instruction of Literacy in the Classroom?
This study examined how elementary teachers used technology to enhance literacy instruction in the classroom. Research was conducted by observing and interviewing both teachers and students in two classrooms, one a blended 3rd/4th grade classroom and the other a 4th grade classroom, on how technology is utilized in the classroom for literacy instruction. The findings showed the use of technology to be highly beneficial for elementary students. The students demonstrated an increase in motivation, attention and engagement. The benefits provided by technology allow students to participate more fully in the educational opportunities of the 21st century and helped students gain the skills necessary to be successful in today’s society
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