Theoretical and Empirical Investigation of Fourier Trajectory Analysis for System Discrimination

With few exceptions, simulation output analysis has focused on static characterizations, to determine a property of the steady-state distribution of a performance metric such as a mean, a quantile, or the distribution itself. Analyses often seek to overcome difficulties induced by autocorrelation of the output stream. But sample paths generated by stochastic simulation exhibit dynamic behavior that is characteristic of system structure and associated distributions. In this technical report, we investigate these dynamic characteristics, as captured by the Fourier transform of a dynamic simulation trajectory. We find that Fourier coefficient magnitudes can have greater discriminatory power than the usual test statistics, and with simpler analysis resulting from the statistical independence of coefficient estimates at different frequencies. Theoretical and Empirical results are provided

Numerical and Experimental Investigation of the Morphology Development of Expansion Clouds by a Powder Jet Flow

Explosion suppression is often the preferred method of explosion attenuation in industry. The morphology development of suppression clouds is important for the design of necessary coverage of the product. This paper presents a numerical and experimental investigation of the growth of powder dispersion as it expands from a discharge nozzle. A Lagrangian stochastic particle-tracking approach and the RNG k-e turbulence model are adopted in the flow field solver for the dispersed and continuous phases. The flow fields coupled with the particle interactions are predicted. The dispersion characteristics of the expansion of the powder cloud through a pipe for short intervals of time are investigated. This was compared with (1) captured images from experiments, (2) experimental data, and (3) results of previous simulations. Particle positions along the jet are presented. The effects of flow rate on the development of the cloud and a comparison with experimental results are also presented. It is noted that the coverage of the powder cloud can be controlled by the flow rate of the jet, and the developing length of the cloud is more influenced by the flow rate of jet flow than the developing width. The good qualitative agreements achieved are useful for further optimisation of product design

A possible intermediate step in the reorganization of rural elementary education in Iowa

Iowa has a very large number of small rural school districts. Of the 4,870 school corporations in the state, 2,807 are rural independent districts and 1,010 are school townships. There are in the state 12,279 public schools of all types, including kindergartens, rural schools, elementary schools (not rural) and high schools. Of this number, 9,223, or about 75 percent, are one-room rural schools. With one exception the number of such schools in Iowa exceeds that found in any other state. The average enrollment in the one-room rural schools of the state in 1932-33 was only 15.8 students; the average daily attendance was 12.6. These ungraded rural schools of the state enrolled 29 percent of the entire number of pupils but employed 38 percent of the teachers. The first class cities, on the other hand, enrolled 23 percent of the pupils of the state but employed only 16 percent of the teachers. The town and consolidated schools, as a rule, also have small total enrollments and small enrollments per teacher. Before the depression the average salary of teachers of one-room rural schools in Iowa was $722 per year, while that of city elementary teachers was$1,573 per year. When the depression brought a demand for reducing expenses, the rural teacher\u27s wage was cut approximately 35 percent, to $465 per year, and the city elementary teacher\u27s wage was reduced 19 percent, to$1,271 per year. From the foregoing it follows that rural people, in general, may have only teachers of inferior training for their children. Yet, in many instances, the per-pupil cost of such instruction is actually higher than that in the elementary grades of city schools; and it appears, on the whole, that there is no great difference in the per-pupil cost of elementary instruction in the two types of schools. This condition clearly reveals the handicap which children face who are born and reared in the country. Moreover a disadvantage also seems to have fallen upon their parents, whose per capita income, even in normal times, is apparently not more than half of that of the non-farm population. Not only must they accept inferior educational opportunities for their children, but they must pay for such facilities a sum more than twice as much, in relation to their incomes, as that paid by people not living in the country. So far no satisfactory solution has been suggested for the problem of how to provide education for rural children that is equal in quality to that which is generally available to the non-farm children of Iowa. Yet with the establishment of the many graded school systems during the past 3 or 4 decades, and with the more recent improvement of the roads of the state, it has seemed that an acceptable solution was gradually becoming possible. In fact, for some time there has been reason to believe that not nearly all of the one-room schools being maintained in Iowa are really needed; many children attending a considerable number of them apparently could be transported to nearby graded school systems and educated at a total cost actually no greater than that being paid at present, provided the patrons of such one-room schools desired to do so. lf arrangements could be made, therefore, whereby the rural and non-rural children of Iowa would attend the same schools they would enjoy more nearly equal educational advantages and opportunities. To remove the present educational handicap of all rural children of Iowa in this manner, however, would entail a considerable increase in educational costs.1 For how many of them it might be removed without additional cost has been determined for a considerable part of the state in connection with an investigation, the results of which are reported in the following pages. Nothing presented in this bulletin, however, suggests any changes in the existing school systems, other than those which would and could at present be taken purely upon local initiative

Full Scale Alternative Catalyst Testing for Bosch Reactor Optimization

Current air revitalization technology onboard the International Space Station (ISS) cannot provide complete closure of the oxygen and hydrogen loops. This makes re-supply necessary, which is possible for missions in low Earth orbit (LEO) like the ISS, but unviable for long term space missions outside LEO. In comparison, Bosch technology reduces carbon dioxide with hydrogen, traditionally over a steel wool catalyst, to create water and solid carbon. The Bosch product water can then be fed to the oxygen generation assembly to produce oxygen for crew members and hydrogen necessary to reduce more carbon dioxide. Bosch technology can achieve complete oxygen loop closure, but has many undesirable factors that result in a high energy, mass, and volume system. Finding a different catalyst with an equal reaction rate at lower temperatures with less catalyst mass and longer lifespan would make a Bosch flight system more feasible. Developmental testing of alternative catalysts for the Bosch has been performed using the Horizontal Bosch Test Stand. Nickel foam, nickel shavings, and cobalt shavings were tested at 500 C and compared to the original catalyst, steel wool. This paper presents data and analysis on the performance of each catalyst tested at comparable temperatures and recycle flow rates

The WET: Is it a Good Drop?

The wine equalisation tax (WET), introduced by the A New Tax System (Wine Equalisation Tax) Act 1999 (Cth), is, in essence, a wholesale sales tax on certain wine containing a specified content of potable alcohol that is sold for consumption in Australia. The apparent fiscal purpose of the Act is to reduce and recoup the public costs of alcohol abuse. The hallmarks of sound tax legislation are traditionally encapsulated in the tax policy principles of simplicity, equity, economic efficiency and fiscal adequacy. This article explores the extent to which these hallmarks are reflected in the rules of the Act. The authors conclude that the WET is not a "good tax" in light of any of the principles, and its deficiencies raise the threshold issue of whether alcohol taxation is an appropriate way to address the public costs of alcohol abuse. In the authors' opinion, there is no valid argument for its retention

Montmorency cherry supplementation improves 15-km cycling time-trial performance

This is the final version. Available on open access from Springer Verlag via the DOI in this recordAim: Montmorency cherries are rich in polyphenols that possess antioxidant, anti-inflammatory and vasoactive properties. We investigated whether 7 d Montmorency cherry powder supplementation improved cycling time-trial (TT) performance. Methods: 8 trained male cyclists (V̇O2peak: 62.3 ± 10.1 ml.kg-1.min-1) completed 10-min steady state (SS) cycling at ~65% V̇O2peak followed by a 15-km TT on two occasions. Participants consumed 6 pills per day (Montmorency cherry powder, MC; anthocyanin 257 mg·d−1 or dextrose powder, PL) for a 7 d period, 3 pills in the morning and evening. Capillary blood [lactate] was measured at baseline, post SS and post TT. Pulmonary gas exchange and tissue oxygenation index (TOI) of m.vastus lateralis via near-infrared spectroscopy, were measured throughout. Results: TT completion time was 4.6 ± 2.9% faster following MC (1506 ± 86 s) supplementation compared to PL (1580 ± 102 s; P=0.004). Blood [lactate] was significantly higher in MC after SS (PL: 4.4 ± 2.1 vs. MC: 6.7 ± 3.3 mM, P=0.017) alongside an elevated baseline TOI (PL: 68.7 ± 2.1 vs. MC: 70.4 ± 2.3%, P=0.018). Discussion: Montmorency cherry supplementation improved 15-km cycling TT performance. This improvement in exercise performance was accompanied by enhanced muscle oxygenation suggesting that the vasoactive properties of the Montmorency cherry polyphenols may underpin the ergogenic effects

Evaluation of Sorbents for Acetylene Separation in Atmosphere Revitalization Loop Closure

State-of-the-art carbon dioxide reduction technology uses a Sabatier reactor to recover water from metabolic carbon dioxide. In order to maximize oxygen loop closure, a byproduct of the system, methane, must be reduced to recover hydrogen. NASA is currently exploring a microwave plasma methane pyrolysis system for this purpose. The resulting product stream of this technology includes unreacted methane, product hydrogen, and acetylene. The hydrogen and the small amount of unreacted methane resulting from the pyrolysis process can be returned to the Sabatier reactor thereby substantially improving the overall efficiency of the system. However, the acetylene is a waste product that must be removed from the pyrolysis product. Two materials have been identified as potential sorbents for acetylene removal: zeolite 4A, a commonly available commercial sorbent, and HKUST-1, a newly developed microporous metal. This paper provides an explanation of the rationale behind acetylene removal and the results of separation testing with both material