Axisymmetric two-phase perfect gas performance program

Computer program calculates the inviscid axisymmetric nozzle expansion of propellant systems having both gaseous and condensed exhaust products. The program uses velocity and thermal lags and will perform calculations for contoured and conical nozzles

Improved Two-Dimensional Kinetics (TDK) computer program

Fluid properties, the boundary layer module, and regenerative cooling are discussed. Chemistry, low density flow effects, test cases, input and output for TDK, and documentation are also discussed

Additional support for the TDK/MABL computer program

An advanced version of the Two-Dimensional Kinetics (TDK) computer program was developed under contract and released to the propulsion community in early 1989. Exposure of the code to this community indicated a need for improvements in certain areas. In particular, the TDK code needed to be adapted to the special requirements imposed by the Space Transportation Main Engine (STME) development program. This engine utilizes injection of the gas generator exhaust into the primary nozzle by means of a set of slots. The subsequent mixing of this secondary stream with the primary stream with finite rate chemical reaction can have a major impact on the engine performance and the thermal protection of the nozzle wall. In attempting to calculate this reacting boundary layer problem, the Mass Addition Boundary Layer (MABL) module of TDK was found to be deficient in several respects. For example, when finite rate chemistry was used to determine gas properties, (MABL-K option) the program run times became excessive because extremely small step sizes were required to maintain numerical stability. A robust solution algorithm was required so that the MABL-K option could be viable as a rocket propulsion industry design tool. Solving this problem was a primary goal of the phase 1 work effort

The prime number theorem

Thesis (M.A.)--Boston University.In Chapter 1 of this thesis we give some elementary definitions and prove the following three theorems: 1.1 Every positive integer n greater than one can be expressed in the form n=p1p2...pk where each of the pi is a prime number. 1.2 Every integer n greater than one can be expressed in standard form in one and only one way. If we write n=(p1^a1)(p2^a2).....(pj^aj), where p1< p2 <...< pj and each ai is greater than 0, then n is expressed in standard form. 1.3 The number of prime numbers is infinite [TRUNCATED

Engineering and programming manual: Two-dimensional kinetic reference computer program (TDK)

The Two Dimensional Kinetics (TDK) computer program is a primary tool in applying the JANNAF liquid rocket thrust chamber performance prediction methodology. The development of a methodology that includes all aspects of rocket engine performance from analytical calculation to test measurements, that is physically accurate and consistent, and that serves as an industry and government reference is presented. Recent interest in rocket engines that operate at high expansion ratio, such as most Orbit Transfer Vehicle (OTV) engine designs, has required an extension of the analytical methods used by the TDK computer program. Thus, the version of TDK that is described in this manual is in many respects different from the 1973 version of the program. This new material reflects the new capabilities of the TDK computer program, the most important of which are described

Selecting children for head CT following head injury

OBJECTIVE: Indicators for head CT scan defined by the 2007 National Institute for Health and Care Excellence (NICE) guidelines were analysed to identify CT uptake, influential variables and yield. DESIGN: Cross-sectional study. SETTING: Hospital inpatient units: England, Wales, Northern Ireland and the Channel Islands. PATIENTS: Children (3 years were much more likely to have CT than those <3 years (OR 2.35 (95% CI 2.08 to 2.65)). CONCLUSION: Compliance with guidelines and diagnostic yield was variable across age groups, the type of hospital and region where children were admitted. With this pattern of clinical practice the risks of both missing intracranial injury and overuse of CT are considerable

Windbreaks for Snow Management

In areas of high winds and blowing snow, windbreaks can reduce the amount of effort spent on snow management. They can be designed to spread snow across a large area or to confine it to a relatively small storage area. The design of your windbreak will depend on your objective. Field windbreaks designed to distribute snow evenly across a field should be tall and porous. In contrast, windbreaks designed to capture snow and control drifting should have multiple rows with high density. There is no one set design, number of rows, or width of planting that is ideal for every circumstance. The design of your tree planting should be done with your needs and winter conditions in mind. In some cases, landowners may choose to relocate fences, driveways, or feedlots in order to take full advantage of their windbreak. Remember, a tree planting is a long-term investment and it pays to consider all alternative designs before installation