Describes habits, predators, morphology, sexual variation, pelages, and distribution of pocket gophers. Describes genera and group relations. Describes, lists locations and distribution, and provides a key for species and subspecies.

From Summary: "An accurate determination of the end-gas condition was attempted by applying a refined method of analysis to experimental results. The results are compared with those obtained in Technical Report no. 655. The experimental technique employed afforded excellent control over the engine variables and unusual cyclic reproducibility. This, in conjunction with the new analysis, made possible the determination of the state of the end-gas at any instant to a fair degree of precision. Results showed that for any given maximum pressure the maximum permissible end-gas temperature increased as the fuel-air ratio was increased. The tendency to detonate was slightly reduced by an increase in residual gas content resulting from an increase in exhaust backpressure with inlet pressure constant."

Technical report regarding he purpose of the investigation was to evaluate the Chicago mass spectrograph as an analytical instrument for solids.

"A method is developed of easily determining the performance of a compressor system relative to that of the power section for a given altitude. Because compressors, reciprocating engines, and turbines are essentially flow devices, the performance of each of these power-plant components is presented in terms of similar dimensionless ratios. The pressure and temperature changes resulting from restrictions of the charge-air flow and from heat transfer in the ducts connecting the components of the power plant are also expressed by the same dimensionless ratios and the losses are included in the performance of the compressor" (p. 119).

The preignition characteristics of the R-2800 cylinder, as effected by fuel consumption, engine operating variables, and spark plug type and condition, were evaluated. The effects on preignition-limited performance of various percentages of aromatics (benzene, toluene, cumene, xylene) in a base fuel of triptane were investigated. Two paraffins (triptane and S + 6.0 ml TEL/gal) and two refinery blends (28-R and 33-R) were preignition rated. The effect of changes in the following engine operating variables on preignition limit was determined: inlet-air temperature, rear spark plug gasket temperature, engine speed, spark advance, tappet clearance, and oil consumption. Preignition limits of the R-2800 cylinder using Champion C34S and C35S and AC-LS86, LS87, and LS88 spark plugs were established and the effect of spark plug deterioration was investigated.

The following report summarizes research done on dissolving uranium from phosphate rock and superphosphate and recovering it from solution in a more concentrated form.

Report presenting a method for the design of supersonic-wind-tunnel nozzles that produce uniform flow over a continuously variable Mach number range without the use of flexible walls. Experimental results from a preliminary investigation of the tunnel are included, including calibration survey of flow, Mach number distributions, and pressure gradients are provided.

Report presenting an experimental and analytical investigation of the flutter of uniform sweptback cantilever wings. The experiments used groups of wings sweptback by rotating and by shearing with angles of sweep ranging from 0 to 60 degrees. Results regarding the experimental investigation and a discussion and comparison of the analytical and experimental results are provided.

An effort to develop a control on the air velocity at the door opening of a fume hood.

The results of power-off force tests and flight tests of a model with a thin unswept low-aspect-ratio wing are presented. The tests were made with the flaps retracted and deflected. The effects on the lateral flight characteristics of decreasing directional stability were noted.

This report follows and experiment that was performed to determine the visual efficiency of a phosphor when bombarded by alpha particles.

From Introduction: "Data are presented in graphical form to show the engine performance over a range of altitudes from 5000 to 50,000 feet and flight Mach numbers from 0.21 to 0.97. Curves are presented to show the windmilling characteristics of the engine. All engine performance data obtained in the investigation are also presented in tabular form."

"The hydrodynamic characteristics of a 1/10-size powered dynamic model of the XP5Y-1 flying boat were determined in Langley tank no. 1. Stable take-offs were possible at all practicable positions of the center of gravity and flap deflections. An increase in gross load from 123.5 to 150.0 pounds (21.5 percent) had only a slight effect on the stable range for take-off" (p. 1).

Report discussing the progress of the Ames Laboratory in metallurgy for the period from April, 1949 through September, 1949.

Uranium can be rolled from cast metal or forged ingot to sheet satisfactory for cupping, deep drawing, and similar fabrication procedures by a combination of hot breakdown in the neighborhood of 600 deg C and warm finishing at 225 to 325 deg C. Sheet may also be obtained by hot rolling alone and by warm rolling alone. However, it is difficult to secure a uniform, controlled grain size by hot rolling only and warm rolling is time consuming because of the limited reduction per pass obtainable. The combination of hot and warm rolling afforded best and most practical method to secure good quality sheet in the quantity required. The percent reduction by hot working does not appear to be critical, but at least 60% warm reduction is desirable to obtain complete and controlled grain size by recrystallization with high ductility and strength properties. Except for research investigation, rolling of uranium below 225 deg C is not recommended. In the temperature range considered (below 225 deg C), reduction is difficult and must be limited to one to two percent if edge cracking is to be avoided. Hot rolling of unplated uranium from the as-cast or as-forged surface is recommended, using a …

Summary: "This investigation showed that a sound , weather-resistant coating can be applied to uranium that the surface to be plated is cleaned and etched properly. Using the proposed two-bath plating method at 80 C., a four-mil nickel coat can be deposited in thirteen hours."

Report presenting the results of static tests conducted for the purpose of determining the lift forces and hinge moments associated with a flat-plate paddle vane, externally hinged near a rocket-nozzle exit and operating on the jet for vane deflection angles ranging from -4 degrees to 25 degrees. Results regarding vane aerodynamic characteristics, performance of rocket motor, and vane erosion

Abstract: "The effects of acidity on extraction of vanadium and molybdenum by diethyl ether are described. Solubility data for several vanadium compounds in nitrate process solutions are presented. Preliminary results on the extraction of uranium from process slurries by tributyl phosphate are reported, including data on the contaminants extracted with the uranium."

Report presenting an investigation to determine the aerodynamic characteristics of a wing-fuselage configuration with a wing with quarter-chord line swept back 35 degrees, an aspect ratio of 4, a taper ratio of 0.6, and an NACA 65A006 airfoil section. Lift, drag, and pitching-moment characteristics, downwash angles, and wake characteristics for various angles of attack and Mach numbers are provided.

A report about metallurgy, chemistry, and physics of metals and alloys. Particular metals include zirconium, thorium, and vanadium metal as well as other earth metals.

The following document analyzes plutonium in urine which uses nuclear track film for evaluation of the quantity of separated plutonium.

The relative physiological and toxicological properties of americium and plutonium have been studied following their intravenous administration to rats. The urinary and fecal excretion of americium was similar to that of plutonium administered as Pu(N03)4. The deposition of americium the tissues and organs of the rat was also similar to that observed for plutonium. The liver and the skeleton were the major sites of deposition. Zirconium citrate administered 15 minutes after injection of americium increased the urinary excretion of americium and decreased the amount found in the liver and the skeleton at 4 and 16 days. LD305° studies showed americium was slightly less toxic when given in the acute toxic range than was plutonium. The difference was, however, too slight to be important in establishing a larger tolerance dose for americium. Survival studies, hematological observations, bone marrow observations, comparison of tumor incidence and incidences of skeletal abnormalities indicated that americium and plutonium have essentially the same chronic toxicity when given on an equal basis. These studies support the conclusion that the tolerance values for americium should be essentially the same as those for plutonium.

Abstract: "The purpose of the investigation was to study the effects of gamma radiation from a cobalt-60 source on the physical properties and halogen evolution from the plastics polyvinyl chloride and polymonochlorotrifluoroethylene. Samples exposed for 2 to 28 days to a source of approximately 25,000 Roentgens per minute showed an appreciable evolution of both fluorine and chlorine. Tests on polymonochlorotrifluoroethylene for tensile, impact, and shear strength showed rapidly decreasing values as the radiation exposure was increased. Similar physical tests on exposed polyvinyl chloride showed increased impact and shear strengths and a lower tensile strength."

From introduction: This report contains the results of field tests for the U.S. AEC on the use of the seismic geophysical method for tracing "buried channels" in the Monument Valley area, Arizona.