Physical Sciences and Mathematics Commons^™

Digital Demodulator-Correlator, James C. Fletcher, James W. Layland, Warren L. Martin, Arthur I. Zygielbaum, Richard M. Goldstein, William P. Hubbard

School of Natural Resources: Faculty Publications

Apparatus for demodulation and correlation of a code modulated 10 MHz signal is comprised of a sample and hold analog-to-digital (A/D) converter synchronized by a frequency coherent 40 MHz pulse to obtain four evenly spaced samples A1,B1A2 and B2 of each cycle of the signal, and means for adding, or subtracting, each sample to, or from, one of four accumulators to form the sums:

SI, = (A1-A2) M1

Sia=; (A1-A2) M2

S2, = (B1 - B2) M1

S2= (B1-B2) M2

where

M1 = 10 MHz Reference . Receiver Code A0' M2 = 10 MHz. Reference . Receiver Code A90'

M2 …

The Rush Creek Structure, Garden County, Nebraska, Robert F. Diffendal Jr.

School of Natural Resources: Faculty Publications

Detailed field mapping of surface outcrops in southern Garden County, Nebraska, has revealed a drop of 200 feet in three miles in the elevation of the contact between the Ogallala and pre-Ogallala (probably Brule) Formations exposed on the east side of Rush Creek. Beds of silt, sand, siltstone, and volcanic ash in the are a locally dip to the northwest at angles of up to 8½°. The contact between the two formations cannot be seen on the west side of Rush Creek but beds in the Ogallala Formation there dip to the north and northeast. The unusually long valley of …

Microhabitat Selection In Two Species Of Heteromyid Rodents, Cliff A. Lemen, Michael L. Rosenzweig

School of Natural Resources: Faculty Publications

An experiment was conducted to determine the microhabitat preferences of two heteromyid rodents, Dipodomys ordi and Perognathus flavus. This experiment used marked seeds and the atomic absorption spectrophotometer in order to study the environment as a mosaic of microhabitats. The results of our analysis indicate that these two heteromyids are microhabitat selectors. The preferences of the rodents are, D. ordi: grass habitat 0.0%, near grass habitat 22.5%, open habitat 77.4%, and P. flavus: grass habitat 46.2%, near grass habitat 32.2%, open habitat 21.4%. The overlap between the two species is only 0.43.

Seed Size Selection In Heteromyids: A Second Look, Cliff A. Lemen

School of Natural Resources: Faculty Publications

The general conclusion of this paper is that heteromyids do not select seed sizes on the basis of their body size. My conclusion comes from the analysis of new data from central New Mexico, analysis of data in the literature on food habits of heteromyids, and a re-analysis of Brown and Lieberman (1973) and Brown (1975). All of these sources agree that no seed size selection exists.

Although no pattern of simple seed size selection was found, interesting differences were noticed among species. First, the tendency to husk appears to be related to the size of the rodent. Second, large …

Local And Regional Components Of Sensible Heat Advection, Thomas W. Brakke, Shashi B. Verma, Norman J. Rosenberg

School of Natural Resources: Faculty Publications

Detailed knowledge of the advection of sensible heat is necessary to understand the energy balance of the evaporating surface in many parts of the world. Sensible hear advection can result from regional and/or local sources. The local and regional components of sensible heat advection (Aloc and Areg, respectively) are identified and their magnitudes in a semi-arid to sub-humid zone are established in the work reported here. Measurements of dry- and wet-bulb air temperature, wind speed and net radiation were made above an irrigated alfalfa field with relatively dry surrounding upwind at Mead, NE. A modified Bowen ratio-energy balance method which …

Shelter Effects On Growth And Yield Of Corn - Nebraska, U.S.A., James R. Brandle

School of Natural Resources: Faculty Publications

No abstract provided.

Turbulent Exchange Coefficients For Sensible Heat And Water Vapor Under Advective Conditions, Shashi Verma, Norman J. Rosenberg, Blaine L. Blad

School of Natural Resources: Faculty Publications

Results are presented of micrometeorological measurements made over alfalfa and soybeans under conditions of sensible heat advection at Mead, Neb. The sensible heat advection phenomenon reported here is of a regional rather than a local nature. The exchange coefficient for sensible heat (Kh) is found to be generally greater than the exchange coefficient for water vapor (Kw). This result contradicts the usaul assumption of equality of Kh and Kw under nonadvection (lapse or unstable) conditions when the net transfer of both sensible heat and water vapor are away from the earth's surface. Under advective conditions, however, heat and water vapor …

Extreme Evapotranspiration By Irrigated Alfalfa: A Consequence Of The 1976 Midwestern Drought, Norman J. Rosenberg, Shashi Verma

School of Natural Resources: Faculty Publications

The rate of evapotranspiration by irrigated alfalfa at Mead, NE (41°09'N; 96°30'W, elevation 354 m) reached record levels in 1976. Evapotranspiration was measured with precision weighing lysimeters in a field 1.9 ha in size. Evapotranspiration ranged during the growing season from 4.75 to 14.22 mm day^–1 and exceeded 10 mm day­^–1 on one-third of the days studied. On each day of study the ratio of latent heat flux density (LE) to the sum of the net radiation and soil heat flux densities (Rn+S) was such that LE/ (Rn+S) > 1, indicating the occurrence of significant sensible heat advection. On …