Steady-State Thermomechanical Finite Element Analysis of Elastoviscoplastic Metal Forming Processes (open access)

Steady-State Thermomechanical Finite Element Analysis of Elastoviscoplastic Metal Forming Processes

Extrusion and rolling processes exhibiting large amounts of plastic flow are analyzed using a finite element technique that is based on a modified creeping viscous flow approximation. The technique, called the initial stress-rate method, iteratively corrects creeping viscous flow solutions to generate results that include elastic response. The momentum equations have been coupled with the energy equation to provide the capability to predict thermomechanical response during forming operations.
Date: January 1, 1977
Creator: Dawson, P.R. & Thompson, E.G.
System: The UNT Digital Library
Geochemical reconnaissance for uranium in the arid regions of the western United States (open access)

Geochemical reconnaissance for uranium in the arid regions of the western United States

In developing the sampling strategy for the seven western states, the Lawrence Livermore Laboratory (LLL) divided the region into geologic and physiographic provinces. A large part of the LLL region of responsibility lies within the arid to semi-arid Basin and Range province. This region is characterized as an area of rather complex geology with internal drainage. The desert-like conditions in many parts of this region result in a unique set of problems which requires a unique reconnaissance program. In this paper, I will describe some of the features of the LLL program which are keyed to the desert environment in the northern Basin and Range province.
Date: March 1, 1977
Creator: Leach, D. L., Jr.
System: The UNT Digital Library
Salt Method for Determining Pond Volume (open access)

Salt Method for Determining Pond Volume

Abstract: "Present methods of determining pond volume are time-consuming and laborious. This paper describes a simple, rapid method for determining water volume in ponds by measuring the change in chloride concentration caused by the addition of a known weight of salt. Mean volume estimates derived by this method were not significantly different (F-test; 0.01 level) from those obtained by multiplying surface area by mean depth or measuring the flow rate through fill pipes."
Date: January 1977
Creator: Provine, William C.
System: The Portal to Texas History
Experimental evaluation of a fixed collector employing vee-trough concentrator and vacuum tube receivers (open access)

Experimental evaluation of a fixed collector employing vee-trough concentrator and vacuum tube receivers

A test bed for experimental evaluation of a fixed solar collector which combines an evacuated glass tube solar receiver with a flat plate/black chrome plated copper absorber and an asymmetric veetrough concentrator was designed and constructed. Earlier predictions of thermal performance were compared with test data acquired for a bare vacuum tube receiver; and receiver tubes with Alzak aluminum, aluminized FEP Teflon film laminated sheet metal and second surface ordinary mirror reflectors. Test results and system economics as well as objectives of an ongoing program to obtain long-term performance data are discussed.
Date: January 1, 1977
Creator: Selcuk, M. K.
System: The UNT Digital Library