The Use of Weather Data and Evapotranspiration Requirements to Estimate the Marginal Value Product of Irrigation and the Profit Maximizing Irrigation Level for Corn in the Texas Panhandle

The declining availability of irrigation water from the Ogallala aquifer combined with increasing energy costs make irrigation strategies much more critical. Maximizing yield reduces profit by between $22 and$158 per acre depending on the combination of corn and natural gas prices.corn, irrigation efficiency, water response function, evapotranspiration, Crop Production/Industries, Land Economics/Use, Research and Development/Tech Change/Emerging Technologies,

Diode laser 87Rb optical pumping in an evacuated wall-coated cell

The evacuated wall coated sealed cell coupled with diode laser optical pumping offers a number of attractive potential advantages for use in Rb or Cs atomic frequency standards. An investigation of systematic effects is required to explore possible limitations of the technique. The use of diode laser optical pumping of 87 Rb in an evacuated wall coated sealed cell is presented. Experimental results/discussion to be presented include the signal strength and line broadening of the 0 - 0 hyperfine resonance as a function of light intensity for the D1 optical transitions (F - F prime) - (2 1 prime) and (2 - 2 prime), shift of the 0 - 0 hyperfine frequency as a function of laser intensity and de-tuning from optical resonance, and diode laser frequency stabilization techniques

A 128K-bit CCD buffer memory system

A prototype system was implemented to demonstrate that CCD's can be applied advantageously to the problem of low power digital storage and particularly to the problem of interfacing widely varying data rates. 8K-bit CCD shift register memories were used to construct a feasibility model 128K-bit buffer memory system. Peak power dissipation during a data transfer is less than 7 W., while idle power is approximately 5.4 W. The system features automatic data input synchronization with the recirculating CCD memory block start address. Descriptions are provided of both the buffer memory system and a custom tester that was used to exercise the memory. The testing procedures and testing results are discussed. Suggestions are provided for further development with regards to the utilization of advanced versions of CCD memory devices to both simplified and expanded memory system applications

Creep and creep rupture of strongly reinforced metallic composites

A creep and creep damage theory is presented for metallic composites with strong fibers. Application is to reinforced structures in which the fiber orientation may vary throughout but a distinct fiber direction can be identified locally (local transverse isotropy). The creep deformation model follows earlier work and is based on a flow potential function that depends on invariants reflecting stress and the material symmetry. As the focus is on the interaction of creep and damage, primary creep is ignored. The creep rupture model is an extension of continuum damage mechanics and includes an isochronous damage function that depends on invariants specifying the local maximum transverse tension and the maximum longitudinal shear stress. It is posited that at high temperature and low stress, appropriate to engineering practice, these stress components damage the fiber/matrix interface through diffusion controlled void growth, eventually causing creep rupture. Experiments are outlined for characterizing a composite through creep rupture tests under transverse tension and longitudinal shear. Application is made to a thin-walled pressure vessel with reinforcing fibers at an arbitrary helical angle. The results illustrate the usefulness of the model as a means of achieving optimal designs of composite structures where creep and creep rupture are life limiting

A creep model for metallic composites based on matrix testing: Application to Kanthal composites

An anisotropic creep model is formulated for metallic composites with strong fibers and low to moderate fiber volume percent (less than 40 percent). The idealization admits no creep in the local fiber direction and assumes equal creep strength in longitudinal and transverse shear. Identification of the matrix behavior with that of the isotropic limit of the theory permits characterization of the composite through uniaxial creep tests on the matrix material. Constant and step-wise creep tests are required as a data base. The model provides an upper bound on the transverse creep strength of a composite having strong fibers embedded in a particular matrix material. Comparison of the measured transverse strength with the upper bound gives an assessment of the integrity of the composite. Application is made to a Kanthal composite, a model high-temperature composite system. Predictions are made of the creep response of fiber reinforced Kanthal tubes under interior pressure

A Review of the Proposed Michigan Rules of Evidence

On January 6, 1977, the Supreme Court of Michigan entered an order stating that it is considering adoption of the proposed Michigan Rules of Evidence which were submitted to the Court by the committee which it appointed in March 1975. The Court has solicited comments from interested persons regarding the proposed rules. A copy of the Supreme Court\u27s order is published in this issue of the Bar Journal. The proposed rules are published in the January 26, 1977, issue of North Western Reporter, Second Series (Michigan Edition). The purpose of this article is to review in general the background and substance of the proposed rules. More detailed information concerning the rules may be obtained by consulting the text of the rules and the committee notes thereto. It is beyond the scope of this article to discuss in detail the policy considerations supporting adoption of each proposed rule which conflicts with prior Michigan law. For the most part the proposed rules are identical with the Federal Rules of Evidence and the policy considerations favoring adoption of the rules are discussed in the Federal Advisory Committee Notes and the legislative history of the Federal Rules

A Review of the Proposed Michigan Rules of Evidence

On January 6, 1977, the Supreme Court of Michigan entered an order stating that it is considering adoption of the proposed Michigan Rules of Evidence which were submitted to the Court by the committee which it appointed in March 1975. The Court has solicited comments from interested persons regarding the proposed rules. A copy of the Supreme Court\u27s order is published in this issue of the Bar Journal. The proposed rules are published in the January 26, 1977, issue of North Western Reporter, Second Series (Michigan Edition). The purpose of this article is to review in general the background and substance of the proposed rules. More detailed information concerning the rules may be obtained by consulting the text of the rules and the committee notes thereto. It is beyond the scope of this article to discuss in detail the policy considerations supporting adoption of each proposed rule which conflicts with prior Michigan law. For the most part the proposed rules are identical with the Federal Rules of Evidence and the policy considerations favoring adoption of the rules are discussed in the Federal Advisory Committee Notes and the legislative history of the Federal Rules