Mechanical Engineering Commons^™

Test 1166: Allis-Chalmers 7040 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF TEST REPORT GENERAL CONDITIONS East tractor is a production model equipped for common usage. Power consuming accessories can be disconnected only when it is convenient for the operator to do so in practice. Additional weight can be added as ballast if the manufacturer regularly supplies it for sale. The static tire loads and the inflation pressures muse conform to recommendations in the Tire Standards published by the Society of Automotive Engineers. PREPARATION FOR PERFORMANCE RUNS The engine crank case is drained and refilled with a measured amount of new oil conforming to specifications in the operator’s manual. The …

Test 1162: Steiger Bearcat Ii, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF TEST REPORT

GENERAL CONDITIONS

East tractor is a production model equipped for common usage. Power consuming accessories can be disconnected only when it is convenient for the operator to do so in practice. Additional weight can be added as ballast if the manufacturer regularly supplies it for sale. The static tire loads and the inflation pressures muse conform to recommendations in the Tire Standards published by the Society of Automotive Engineers.

PREPARATION FOR PERFORMANCE RUNS

The engine crank case is drained and refilled with a measured amount of new oil conforming to specifications in the operator’s manual. The …

Test 1157: John Deere 2630 And 2640 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF TEST REPORT GENERAL CONDITIONS East tractor is a production model equipped for common usage. Power consuming accessories can be disconnected only when it is convenient for the operator to do so in practice. Additional weight can be added as ballast if the manufacturer regularly supplies it for sale. The static tire loads and the inflation pressures muse conform to recommendations in the Tire Standards published by the Society of Automotive Engineers. PREPARATION FOR PERFORMANCE RUNS The engine crank case is drained and refilled with a measured amount of new oil conforming to specifications in the operator’s manual. The …

Diurnal Solar Heating And Cooling Of A Water Reservoir, Stephen Patrick Lepper

Masters Theses

"The transient diurnal heating of a water reservoir by solar radiation; and its cooling by surface convection, evaporation, and radiation emission was analytically modeled. The directional and spectral properties of the incident solar radiation, the air-water interface, and the selective attenuation of radiant energy by the water were properly included in the analysis. The diurnal vertical temperature distribution was predicted by numerically solving the energy equation using a finite difference technique. It was determined that the surface boundary conditions and the selective absorption of radiant energy by the water strongly influence the thermal stratification of stagnant water.

The diurnal compensating …

An Analytical And Experimental Study Of The Dynamic Response Of A Press, Woosoon Bai

Doctoral Dissertations

"This dissertation presents a simplified mathematical model and computer simulation of the vertical motion of a press. The model is verified by comparing simulation results with actual field measurements.

Using this model, the computer simulation is then extended to study the dynamic response of a bolted press, one with loosened anchor bolts, and one which is isolated. Press performance, in terms of acceleration of the press, velocity of its foundation, and forces transmitted to the foundation, is analyzed in relation to the foundation mass and the stiffness of the isolators, where applicable. Comparative performances of the presses secured by the …

Solid-Fluid Drag Reduction, Ian Radin

Doctoral Dissertations

"Pressure drop measurements were made on a variety of solid-liquid suspension systems in order to study the effects of particle shape and size, concentration, fluid viscosity and tube diameter on drag reduction. Measurements were made over a wide range of Reynolds numbers in two tubes: 1/4 inch and 1 inch in diameter.

Drag reduction could always be obtained with fibrous additives of length-to-diameter ratio greater than 25-35 if the concentration was sufficiently high. The drag reduction behavior of these suspensions is different from that of high polymer and soap solutions. Laminar flow behavior is stabilized giving lower than normal friction …

Transient Thermal Stresses In A Sphere By Local Heating, J. B. Cheung, T. S. Chen, K. Thirumalai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The problem of transient thermal stresses in a solid, elastic, homogeneous, and isotropic sphere is solved for uniform and nonuniform, local surface heating. The temperature solutions are obtained by using separation of variables and integral transformation. The corresponding thermal stresses are derived by superposing a particular displacement potential function on Boussinesq solutions. Numerical solutions for two particular cases of localized heating of a typical brittle spherical solid have been obtained and presented. The results indicate a tensile stress concentration in the interior of the solid below the heated zone. © 1974 by ASME.

Vibration Characteristics Of Free Thin Cylindrical Shells, Floyd M. Cunningham, D. E. Leanhardt

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper considers the flexural vibrations of free thin circular cylinders. A frequency equation is derived using free-free characteristic beam functions to represent the variation of mid-surface shell displacement components, u, v and w, with respect to the axial direction. Timoshenko strain-displacement relations for thin cylinders are used to determine elastic vibratory strain energy. Energy methods are applied to obtain the frequency equation and associated amplitude ratios for each of its roots. This energy solution is checked experimentally using a vibration exciter and numerically using the SABOR IV finite element program. With minor modification, the frequency equation conforms to the …

Dropwise Condensation As Affected By Vapor Diffusion And Molecular Sticking, Salil K. Banerjee

Doctoral Dissertations

"Experimental values of heat flux in dropwise condensation on a gold plated vertical copper surface were determined in presence and absence of (or minute traces of) noncondensable gas. The noncondensable gas concentration varied from 0.0045% to 7.5% over a range of subcooling from 2.155 to 17.13°F and system pressure of 4.124 to 16.67 psia. The calculated heat transfer coefficient ranged from 1,545 to 11,135 Btu/hr-ft²-°F. In the part of the experiment where precautions were taken to avoid the presence of noncondensable gas in the water vapor, much higher values of heat flux were observed. Values of heat transfer coefficient ranging …

Measurements Of Condensation Coefficient Exhibited By Water Drops Grown On Rural Cloud Nuclei, Abbas M. Sinnarwalla

Doctoral Dissertations

"Values of condensation coefficient, ß, were experimentally determined for water drops grown on cloud nuclei in atmospheric air samples. The measured quantities were supersaturation, final drop size (6 to 7.5 µm radius), and time to grow from near dry radius to final radius. The drops were grown in a vertical-flow thermal diffusion chamber, at supersaturations near 0.5 and 1.0%. The final drop sizes were large enough so that ß did not depend upon the size of the nucleus producing a given drop. The average value of ß was 0.025 with a standard deviation of about 0.01"--Abstract, page 2.

Numerical Modeling Of The Early Stage Of Cloud Formation In A Simulation Chamber, Adel Nassif Saad

Doctoral Dissertations

"A numerical model has been developed to simulate the growth of cloud droplets by condensation upon a spectrum of hygroscopic nuclei. The model is applicable to cloud simulation chamber conditions as well as to the study of the role of these nuclei on cloud base microstructure.

Equations are given for the growth by condensation of water vapor on a population of hygroscopic nuclei in a volume being cooled by expansion. The equations are integrated simultaneously, using Hamming's modified predictor-corrector method for given initial conditions, to obtain the droplet size distribution, temperature, pressure, supersaturation, and liquid water content. Temperature fluctuations, sedimentation …