The effect of mixing, radiation, and finite rate combustion upon the flow field and surroundings of the exhaust plumes of rocket engines burning RP1 /kerosene/ and liquid oxygen

Shear layer mixing, hydrocarbon oxidation, and carbon cloud radiation models for liquid rocket engine exhaust plume analysi

Analytical Study of Gravity Effects on Laminar Diffusion Flames

A mathematical model is presented for the description of axisymmetric laminar-jet diffusion flames. The analysis includes the effects of inertia, viscosity, diffusion, gravity and combustion. These mechanisms are coupled in a boundary layer type formulation and solutions are obtained by an explicit finite difference technique. A dimensional analysis shows that the maximum flame width radius, velocity and thermodynamic state characterize the flame structure. Comparisons with experimental data showed excellent agreement for normal gravity flames and fair agreement for steady state low Reynolds number zero gravity flames. Kinetics effects and radiation are shown to be the primary mechanisms responsible for this discrepancy. Additional factors are discussed including elipticity and transient effects

Predictions for the first two positive-parity states of \u3csup\u3e13\u3c/sup\u3eF

We have used a potential model, together with information from 13Be, to compute expected energies and widths for the first two positive-parity states of 13F. Results are (all in MeV) Ep = 2.30 and 4.94 (or 5.26), width ∼0.6 and 0.3 (or 0.4), for 1/2+ and 5/2+, respectively

Matter Radii of \u3csup\u3e29-35\u3c/sup\u3eMg

We have computed matter radii for the ground states of 29–35Mg for a variety of reasonable assumptions about the structure of the relevant states. For cases in which the dominant configuration is generally agreed, our computed radii are in good agreement with experimental ones. For cases in which the dominant configuration is unknown or ambiguous, comparisons between the calculated and experimental Rm do not allow a decision as to the preferred configuration

Mass of \u3csup\u3e18\u3c/sup\u3eMg(g.s.)

We use a potential model, together with spectroscopic factors from a combination of weak coupling and a shell-model calculation, to compute the mass of the ground state of 18Mg, considered as a mirror of 18C. The result is E2p=3.87(10)MeV

Continuum three-body decays of \u3csup\u3e9\u3c/sup\u3eBe(5/2\u3csup\u3e−\u3c/sup\u3e)

We describe and discuss various three-body decay mechanisms for 9Be(5/2−). We find that its decay to n+ 8Be(2+) is a small fraction of the total decay

Excited states of \u3csup\u3e19\u3c/sup\u3eMg

We have calculated energies of the first two excited states of 19Mg by using a model that was previously successful for the ground state. Computed excitation energies are 1.12 and 1.54 MeV for (3/2−) and (5/2−), respectively—somewhat in disagreement with values of 1.38 and 2.14 MeV from a recent experiment

Characterization of the space shuttle reaction control system engine

A computer program was developed and written in FORTRAN 5 which predicts the transient and steady state performance and heat transfer characteristics of a pulsing GO2/GH2 rocket engine. This program predicts the dynamic flow and ignition characteristics which, when combined in a quasi-steady state manner with the combustion and mixing analysis program, will provide the thrust and specific impulse of the engine as a function of time. The program also predicts the transient and steady state heat transfer characteristics of the engine using various cooling concepts. The computer program, test case, and documentation are presented. The program is applicable to any system capable of utilizing the FORTRAN 4 or FORTRAN 5 language

N, P and K budgets for crop rotations on nine organic farms in the UK

On organic farms, where the importation of materials to build/maintain soil fertility is restricted, it is important that a balance between inputs and outputs of nutrients is achieved to ensure both short-term productivity and long-term sustainability. This paper considers different approaches to nutrient budgeting on organic farms and evaluates the sources of bias in the measurements and/or estimates of the nutrient inputs and outputs. The paper collates 88 nutrient budgets compiled at the farm scale in 9 temperate countries. All the nitrogen (N) budgets showed an N surplus (average 83.2 kg N ha-1 year-1). The efficiency of N use, defined as outputs/inputs, was highest (0.9) and lowest (0.2) in arable and beef systems respectively. The phosphorus (P) and potassium (K) budgets showed both surpluses and deficits (average 3.6 kg P ha-1 year-1, 14.2 kg K ha-1 year-1) with horticultural systems showing large surpluses resulting from purchased manure. The estimation of N fixation and quantities of nutrients in purchased manures may introduce significant errors in nutrient budgets. Overall, the data illustrate the diversity of management systems in place on organic farms, and suggest that used together with soil analysis, nutrient budgets are a useful tool for improving the long-term sustainability of organic systems

Attentional Bias And Training In Individuals With High Dental Anxiety

Dental anxiety is common and associated with negative outcomes. According to information-processing models, anxiety is maintained by maladaptive patterns of processing threatening information. Furthermore, attention training interventions can reduce anxiety in one session. Fifty-three individuals with high levels of dental anxiety completed a Posner reaction-time task. Participants were randomized to attention training or control using a dot-probe task, and then attentional bias was remeasured using another Posner task. Participants then completed a script-driven imaginal exposure task. Results indicated that individuals high in dental anxiety exhibit threat-relevant attentional bias. There was mixed evidence about the efficacy of attention training. On the one hand, training did not eliminate attentional bias and training condition did not predict distress during the imagery task. On the other hand, cue dependency scores in the control group were higher for dental than neutral cues, but did not differ in the training group. In addition, cue dependency scores for both dental and neutral cues predicted subjective anxiety in anticipation of the imagery task. The mixed results of training are considered in terms of the possibility that it enhanced attentional control, rather than reducing bias