Neutron attenuation in the old pile shields is dependent more and more on the slowing down characteristics of the iron as the hydrogen is baked out of the masonite. For neutrons above 1 or 2 Mev, iron does a good job by inelastic scattering. However, below this energy attenuation can be done only by the gradual moderation by elastic scattering to thermal energies with subsequent capture in the iron. Since iron is heavy and thus a poor moderator, there is a good possibility that many neutrons of intermediate energy will leak out of a burned out shield. Also, iron has a large dip in its cross section at 25 Kev which might allow a large burst of neutrons at this energy to leak out. Measurements using a lucite moderator with gold foil detectors indicate a large leakage of neutrons of intermediate energy, but interpretation of these measurements is difficult. These considerations prompted an attempt to get a rough idea of the energy distribution of the leakage neutrons through pure iron using a simple qualitative theory.

Average coefficients of thermal expansion of the temperature range 25 C to approximately 425 C are reported for numerous types of graphite. The dependence of thermal expansion on crystal orientation and crystallite size and the effects of oxidation and cold test hole irradiation are discussed. An empirical relationship between thermal expansion and the initial rate of physical expansion under cold test hole irradiation is formulated.

We have recently completed measurement of resonance escape probability in the BNL reactor and in several slightly-enriched uranium light water moderated lattices. In addition, WAPD has made available to us data from other slightly enriched uranium-water lattices, so that about 18 lattices in all have been done.

From Abstract: "This report covers the preliminary literature survey and the screening of activated cesium iodide and several alkali halides to qualitatively determine their luminerscence. The report also includes a proposal of the future work and a proposed budget for the 1957 fiscal year."

Evaluation of the conditions under which the interaction effects of two or more sub-critical quantities of enriched uranium may be safely arranged.

From Introduction: "This report presents the cooling-air requirements of a "paper" air-cooled turbojet engine operating over a wide range of flight Mach numbers and altitudes. The results are presented for a two-stage-turbine turbo-jet engine having a turbine-inlet temperature of 2500^o R and operating at sea-level static conditions and flight Mach numbers from 0.90 to 2.5 and flight altitudes from 40,000 to 70,000 feet. In addition, the effect of decreasing the blade-inlet cooling-air temperature on the required coolant-flow ratio is presented."

Report presenting tests to determine the flight characteristics of an F-86 airplane equipped with a blowing-type boundary-layer-control installation on the trailing-edge flaps. The effectiveness of the flap was determined in conjunction with slatted leading edges and an inflatable rubber boot on the leading edge. Measurements were made of lift, drag, flow requirements, and computations for take-off, climb, and landing.

"Wind-tunnel tests were conducted to determine the effects of a ventral fin on the static characteristics of a triangular-wing airplane model. Data were obtained for angles of sideslip up to 18 degrees at angles of attack 0, 6, 12, and 18 degrees at Mach numbers from 0.25 to 0.94. The results of the tests indicated that the ventral fin did not produce as much yawing moment per unit of exposed area at any angle of sideslip as the vertical tail" (p. 1).

"The theoretical performance of pentaborane has been recalculated using recent data on the vapor pressure of boric oxide. Previous calculations were based upon vapor-pressure data obtained some years ago by a method not as accurate as that employed in current investigations. The recalculated performance data for pentaborane differ appreciably from previously published data and are considered more accurate for evaluation of the relative potentialities of boron-containing fuels" (p. 1).

Report presenting an experimental investigation to evaluate combinations of fuselage and inlet throat boundary-layer removal for a ramp-type side inlet in the 8- by 6-foot supersonic wind tunnel at Mach numbers 1.5, 1.8, and 2.0. Optimum combinations of fuselage and inlet throat boundary-layer removal showed gains in available thrust from 3 to 10 percent over the case of no inlet throat bleed. Results regarding variations of diffuser total-pressure distortion, recovery and external drag coefficients, and net gains in available thrust are provided.

Report presenting an investigation to determine the effects of external ribs, or load carrying fences, on the rolling effectiveness and drag on swept wings of two different stiffnesses. The primary effect of adding fences was a decrease in torsional flexibility and an increase in zero-lift rolling effectiveness. The aerodynamic effects on zero-lift rolling effectiveness due to adding fences are negligible.

From Introduction: "The purpose of this report is to further analyze the turbine performance results of reference 1 with the objective of isolating the contribution of the cooling air to the turbine performance and establishing some systematic relation between these cooling-air effects and the turbine operational parameters."

Report presenting the design details of two transpiration-cooled strut-supported turbine rotor blades. One design uses a sintered blade shell while the other uses a wire blade shell. Ideal coolant flows were found for an effective gas temperature of 1425 degrees Fahrenheit, a coolant temperature of 180 degrees Fahrenheit, and a shell temperature of 600 degrees Fahrenheit.

Report presenting testing of two airplanes, the F6F-3 and F-86A, fitted with servo equipment for varying in flight the lateral and directional stability and handling characteristics and flown by test pilots to simulate the predicted dynamic behavior of six prototype airplanes. Results regarding the aerodynamic characteristics and pilot opinions for each plane are provided.

Report presenting an investigation of a turbojet engine in an altitude test facility to supplement existing data relevant to gas-temperature control in a turbojet engine. The problems associated with gas-temperature control for minimizing turbine-blade damage are considered in the report.

Report presenting a study of the transonic drag associated with varying the vertical location of the horizontal tail of a representative tail-body combination. Factors which significantly influenced the results were flow separation in the horizontal tail-body juncture, afterbody-tail-interference pressure drag, and a downwash over the horizontal tail which resulted from the boundary conditions of the converging afterbody.

Static longitudinal and lateral stability and control data are presented of an investigation on a l/15-scale model of the Goodyear XZP5K airship over a pitch and yaw range of +/-20 deg and 0 deg to 30 deg, respectively, for various rudder and elevator deflections. Two tail configurations of different plan forms were tested and wake and boundary-layer surveys were conducted. Testing was conducted in the Langley full-scale tunnel at a Reynolds number of approximately 16.5 x 10(exp 6) based on hull length, and corresponds to a Mach number of about 0.12.

Memorandum presenting an experimental investigation of the aerodynamic loading on one blade and of a two-blade teetering rotor conducted in forward flight for a tip-speed-ratio range of 0.08 to 0.29 at a disk loading of about 2.4 pounds per square foot and a tip speed of about 480 feet per second. Chordwise loading distributions at five spanwise stations and the variation of section loading and total blade lift with azimuth position are presented. Results regarding the performance data, section aerodynamic loading, spanwise loading distribution, total blade lift, and rotor-disk load distribution are provided.

Report presenting an exploratory investigation of the effectiveness of outboard horizontal tails in reducing the static longitudinal stability changes with lift coefficient associated with many sweptback wings. The results indicated that outboard horizontal tails can be a very effective means of counteracting the trend toward longitudinal instability characteristics of many sweptback wings. Results regarding the effects of changes in horizontal-tail position, effects of wing fences, average downwash at the tail, effects of changing tail size, lift, drag, and pitching-moment characteristics, and effects of flaps are provided.

A preliminary report discussing a diamond-drill exploration in the southern part of the Uravan District.

Electrodialysis in an ion-exchange membrane cell was shown to be technically feasible for the concentration of an azeotropic mixture of HF and water. A flowsheet is presented for recovery of anhydrous HF by distillation and electrodialysis of the azeotropic residue. In the electrodialysis step, 2.6 kwhr of energy per pound of anhydrous product was consumed, with electricity at 1¢ per kilowatt-hour, the total operating cost of the electrodialysis equipment alone, including amortization, would be 6¢ per pound of HF.