Selected microgravity combustion diagnostic techniques

During FY 1989-1992, several diagnostic techniques for studying microgravity combustion have moved from the laboratory to use in reduced-gravity facilities. This paper discusses current instrumentation for rainbow schlieren deflectometry and thermophoretic sampling of soot from gas jet diffusion flames

Doppler radar with multiphase modulation of transmitted and reflected signal

A microwave radar signal is generated and split by a circulator. A phase shifter introduces a series of phase shifts into a first part of the split signal which is then transmitted by antenna. A like number of phase shifts is introduced by the phase shifter into the return signal from the target. The circulator delivers the phase shifted return signal and the leakage signal from the circulator to a mixer which generates an IF signal output at the Doppler frequency. The IF signal is amplified, filtered, counted per unit of time, and the result displayed to provide indications of target sense and range rate. An oscillator controls rate of phase shift in the transmitted and received radar signals and provides a time base for the counter. The phase shift magnitude increases may be continuous and linear or discrete functions of time

Soot formation and radiation in turbulent jet diffusion flames under normal and reduced gravity conditions

Most practical combustion processes, as well as fires and explosions, exhibit some characteristics of turbulent diffusion flames. For hydrocarbon fuels, the presence of soot particles significantly increases the level of radiative heat transfer from flames. In some cases, flame radiation can reach up to 75 percent of the heat release by combustion. Laminar diffusion flame results show that radiation becomes stronger under reduced gravity conditions. Therefore, detailed soot formation and radiation must be included in the flame structure analysis. A study of sooting turbulent diffusion flames under reduced-gravity conditions will not only provide necessary information for such practical issues as spacecraft fire safety, but also develop better understanding of fundamentals for diffusion combustion. In this paper, a summary of the work to date and of future plans is reported

Development and Validation of an Instrument Measuring Determinants of Bystander Intervention to Prevent Sexual Assault: An application of the Reasoned Action Approach

Bystander Intervention (BI) is an evidence-based approach that is considered the gold standard by governmental organizations to reduce sexual assault in college. Few survey instruments are available to measure the predispositions students have towards engaging in BI. Valid and reliable instruments are greatly needed, especially those tailored to BI. The purpose of this study was to develop and validate an instrument based on the reasoned action approach with college students at two U.S. universities. An elicitation of beliefs was accomplished to inform survey items (i.e., behavioral, normative, and control beliefs). Then, an initial draft was developed and sent to an expert panel to establish validity. The final instrument was administered to undergraduate students (n = 291), and further psychometric properties (construct validity and internal consistency reliability) were evaluated. Data were fit into two separate models to evaluate fit. In the first model, a four-factor solution was evaluated (intentions, attitudes, perceived norms, and perceived behavioral control), and while results were modest, the second seven-factor solution model contained a better fit (intentions, instrumental and experiential attitudes, injunctive and descriptive norms, capacity, and autonomy). Researchers and practitioners examining BI in college can use this instrument to measure theory-based determinants of BI to reduce sexual assault

Two-divisibility of the coefficients of certain weakly holomorphic modular forms

We study a canonical basis for spaces of weakly holomorphic modular forms of weights 12, 16, 18, 20, 22, and 26 on the full modular group. We prove a relation between the Fourier coefficients of modular forms in this canonical basis and a generalized Ramanujan tau-function, and use this to prove that these Fourier coefficients are often highly divisible by 2.Comment: Corrected typos. To appear in the Ramanujan Journa

Staggered fermions and chiral symmetry breaking in transverse lattice regulated QED

Staggered fermions are constructed for the transverse lattice regularization scheme. The weak perturbation theory of transverse lattice non-compact QED is developed in light-cone gauge, and we argue that for fixed lattice spacing this theory is ultraviolet finite, order by order in perturbation theory. However, by calculating the anomalous scaling dimension of the link fields, we find that the interaction Hamiltonian becomes non-renormalizable for $g^2(a) > 4\pi$, where $g(a)$ is the bare (lattice) QED coupling constant. We conjecture that this is the critical point of the chiral symmetry breaking phase transition in QED. Non-perturbative chiral symmetry breaking is then studied in the strong coupling limit. The discrete remnant of chiral symmetry that remains on the lattice is spontaneously broken, and the ground state to lowest order in the strong coupling expansion corresponds to the classical ground state of the two-dimensional spin one-half Heisenberg antiferromagnet.Comment: 30 pages, UFIFT-HEP-92-1

Energetic outer radiation belt electron precipitation during recurrent solar activity

Transmissions from three U.S. VLF (very low frequency) transmitters were received at Churchill, Canada, during an event study in May to November, 2007. This period spans four cycles of recurrent geomagnetic activity spaced similar to 27 days apart, with daily Sigma Kp reaching similar to 30 at the peaks of the disturbances. The difference in the amplitude of the signals received during the day and during the night varied systematically with geomagnetic activity, and was used here as a proxy for ionization changes caused by energetic electron precipitation. For the most intense of the recurrent geomagnetic storms there was evidence of electron precipitation from 3 300 keV and similar to 1 MeV trapped electrons, and also consistent with the daily average ULF (ultralow frequency) Pc1-2 power (L = 3.9) from Lucky Lake, Canada, which was elevated during the similar to 1 MeV electron precipitation period. This suggests that Pc1-2 waves may play a role in outer radiation belt loss processes during this interval. We show that the > 300 keV trapped electron flux from POES is a reasonable proxy for electron precipitation during recurrent high-speed solar wind streams, although it did not describe all of the variability that occurred. While energetic electron precipitation can be described through a proxy such as Kp or Dst, careful incorporation of time delays for different electron energies must be included. Dst was found to be the most accurate proxy for electron precipitation during the weak recurrent-activity period studied

An internet-based intervention with brief nurse support to manage obesity in primary care (POWeR+): a pragmatic, parallel-group, randomised controlled trial

Background The obesity epidemic has major public health consequences. Expert dietetic and behavioural counselling with intensive follow-up is effective, but resource requirements severely restrict widespread implementation in primary care, where most patients are managed. We aimed to estimate the effectiveness and cost-effectiveness of an internet-based behavioural intervention (POWeR+) combined with brief practice nurse support in primary care. Methods We did this pragmatic, parallel-group, randomised controlled trial at 56 primary care practices in central and south England. Eligible adults aged 18 years or older with a BMI of 30 kg/m2 or more (or ≥28 kg/m2 with hypertension, hypercholesterolaemia, or diabetes) registered online with POWeR+—a 24 session, web-based, weight management intervention lasting 6 months. After registration, the website automatically randomly assigned patients (1:1:1), via computer-generated random numbers, to receive evidence-based dietetic advice to swap foods for similar, but healthier, choices and increase fruit and vegetable intake, in addition to 6 monthly nurse follow-up (control group); web-based intervention and face-to-face nurse support (POWeR+Face-to-face [POWeR+F]; up to seven nurse contacts over 6 months); or web-based intervention and remote nurse support (POWeR+Remote [POWeR+R]; up to five emails or brief phone calls over 6 months). Participants and investigators were masked to group allocation at the point of randomisation; masking of participants was not possible after randomisation. The primary outcome was weight loss averaged over 12 months. We did a secondary analysis of weight to measure maintenance of 5% weight loss at months 6 and 12. We modelled the cost-effectiveness of each intervention. We did analysis by intention to treat, with multiple imputation for missing data. This trial is registered as an International Standard Randomised Controlled Trial, number ISRCTN21244703. Findings Between Jan 30, 2013, and March 20, 2014, 818 participants were randomly assigned to the control group (n=279), the POWeR+F group (n=269), or the POWeR+R group (n=270). Weight loss averaged over 12 months was recorded in 666 (81%) participants. The control group lost almost 3 kg over 12 months (crude mean weight: baseline 104·38 kg [SD 21·11; n=279], 6 months 101·91 kg [19·35; n=136], 12 months 101·74 kg [19·57; n=227]). The primary imputed analysis showed that compared with the control group, patients in the POWeR+F group achieved an additional weight reduction of 1·5 kg (95% CI 0·6–2·4; p=0·001) averaged over 12 months, and patients in the POWeR+R group achieved an additional 1·3 kg (0·34–2·2; p=0·007). 21% of patients in the control group had maintained a clinically important 5% weight reduction at month 12, compared with 29% of patients in the POWeR+F group (risk ratio 1·56, 0·96–2·51; p=0·070) and 32% of patients in the POWeR+R group (1·82, 1·31–2·74; p=0·004). The incremental overall cost to the health service per kg weight lost with the POWeR+ interventions versus the control strategy was £18 (95% CI −129 to 195) for POWeR+F and –£25 (−268 to 157) for POWeR+R; the probability of being cost-effective at a threshold of £100 per kg lost was 88% and 98%, respectively. No adverse events were reported. Interpretation Weight loss can be maintained in some individuals by use of novel written material with occasional brief nurse follow-up. However, more people can maintain clinically important weight reductions with a web-based behavioural program and brief remote follow-up, with no increase in health service costs. Future research should assess the extent to which clinically important weight loss can be maintained beyond 1 year