Synthesis of calculational methods for design and analysis of radiation shields for nuclear rocket systems

Eight computer programs make up a nine volume synthesis containing two design methods for nuclear rocket radiation shields. The first design method is appropriate for parametric and preliminary studies, while the second accomplishes the verification of a final nuclear rocket reactor design

Orbital Characteristics of the Subdwarf-B and F V Star Binary EC~20117-4014(=V4640 Sgr)

Among the competing evolution theories for subdwarf-B (sdB) stars is the binary evolution scenario. EC~20117-4014 (=V4640~Sgr) is a spectroscopic binary system consisting of a pulsating sdB star and a late F main-sequence companion (O'Donoghue et al. 1997), however the period and the orbit semi-major axes have not been precisely determined. This paper presents orbital characteristics of the EC 20117-4014 binary system using 20 years of photometric data. Periodic Observed minus Calculated (O-C) variations were detected in the two highest amplitude pulsations identified in the EC 20117-4014 power spectrum, indicating the binary system's precise orbital period (P = 792.3 days) and the light-travel time amplitude (A = 468.9 s). This binary shows no significant orbital eccentricity and the upper limit of the eccentricity is 0.025 (using 3 $\sigma$ as an upper limit). This upper limit of the eccentricity is the lowest among all wide sdB binaries with known orbital parameters. This analysis indicated that the sdB is likely to have lost its hydrogen envelope through stable Roche lobe overflow, thus supporting hypotheses for the origin of sdB stars. In addition to those results, the underlying pulsation period change obtained from the photometric data was $\dot{P}$ = 5.4 ($\pm$0.7) $\times$ $10^{-14}$ d d$^{-1}$, which shows that the sdB is just before the end of the core helium-burning phase

Model for Cumulative Solar Heavy Ion Energy and Linear Energy Transfer Spectra

A probabilistic model of cumulative solar heavy ion energy and LET spectra is developed for spacecraft design applications. Spectra are given as a function of confidence level, mission time period during solar maximum and shielding thickness. It is shown that long-term solar heavy ion fluxes exceed galactic cosmic ray fluxes during solar maximum for shielding levels of interest. Cumulative solar heavy ion fluences should therefore be accounted for in single event effects rate calculations and in the planning of space missions

A positive-real design for robotic manipulators

In this paper, we show that feedback-linearization in conjunction with the passivity property of rigid robots can guarantee the robustness of the closed-loop robotic system despite large uncertainties in the inertia matrix. The approach may be extended to the case of uncertain velocity-dependent terms under additional assumptions

A periodically active pulsar giving insight into magnetospheric physics

PSR B1931+24 (J1933+2421) behaves as an ordinary isolated radio pulsar during active phases that are 5-10 days long. However, the radio emission switches off in less than 10 seconds and remains undetectable for the next 25-35 days, then it switches on again. This pattern repeats quasi-periodically. The origin of this behaviour is unclear. Even more remarkably, the pulsar rotation slows down 50% faster when it is on than when it is off. This indicates a massive increase in magnetospheric currents when the pulsar switches on, proving that pulsar wind plays a substantial role in pulsar spin-down. This allows us, for the first time, to estimate the currents in a pulsar magnetospheric during the occurrence of radio emission.Comment: 12 pages, 2 figure

Short Term Indian Club Swinging Improves Shoulder Flexibility

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Lorentz transformations that entangle spins and entangle momenta

Simple examples are presented of Lorentz transformations that entangle the spins and momenta of two particles with positive mass and spin 1/2. They apply to indistinguishable particles, produce maximal entanglement from finite Lorentz transformations of states for finite momenta, and describe entanglement of spins produced together with entanglement of momenta. From the entanglements considered, no sum of entanglements is found to be unchanged.Comment: 5 Pages, 2 Figures, One new paragraph and reference adde

Determining the Effectiveness of Rosemary Essential Oil on the Shelf Life of Ground Beef Under Different Lighting Conditions

This study determined the effectiveness of rosemary extract on the shelf life of ground beef patties under different retail display conditions. Ground beef patties were produced from an 85%:15% blend (lean:fat). Patties were formed from batches of control or amended with rosemary extract. Patties were individually packaged using overwrap. Groups were assigned into one of two lighting groups (3000K and 3500K). Patties were placed in a simulated retail display for 5 d under continuous lighting and rotated once a day. Lipid oxidation and color samples were taken each day. Relating to lipid oxidation, there was no three-way interaction between display day, antioxidant, and light intensity (P \u3e 0.05). There was an interaction observed between antioxidant and day (P \u3c 0.0001). Relating to color spectrometry, L* values presented an interaction between antioxidant and lighting intensity (P = 0.0029). A two-way interaction between day and antioxidant (P = 0.0003) was also shown in a* values and b* values (P = 0.0008). Chroma values displayed an interaction between antioxidant and day (P = 0.0008). The hue data concluded similar results (P = 0.0008); there was an interaction observed between antioxidant × day (P \u3c 0.0001). These results indicate that color instability and degradation can be prevented with the introduction of antioxidants and the reduction of retail display days. These data suggest that antioxidants reduce lipid oxidation regardless of light temperature. Antioxidants can still be used to extend shelf life and improve color stability in ground products

Determining the Effectiveness of Rosemary Essential Oil on the Shelf Life of Ground Beef Under Different Lighting Conditions

This study determined the effectiveness of rosemary extract on the shelf life of ground beef patties under different retail display conditions. Ground beef patties were produced from an 85%:15% blend (lean:fat). Patties were formed from batches of control or amended with rosemary extract. Patties were individually packaged using overwrap. Groups were assigned into one of two lighting groups (3000K and 3500K). Patties were placed in a simulated retail display for 5 d under continuous lighting and rotated once a day. Lipid oxidation and color samples were taken each day. Relating to lipid oxidation, there was no three-way interaction between display day, antioxidant, and light intensity (P \u3e 0.05). There was an interaction observed between antioxidant and day (P \u3c 0.0001). Relating to color spectrometry, L* values presented an interaction between antioxidant and lighting intensity (P = 0.0029). A two-way interaction between day and antioxidant (P = 0.0003) was also shown in a* values and b* values (P = 0.0008). Chroma values displayed an interaction between antioxidant and day (P = 0.0008). The hue data concluded similar results (P = 0.0008); there was an interaction observed between antioxidant × day (P \u3c 0.0001). These results indicate that color instability and degradation can be prevented with the introduction of antioxidants and the reduction of retail display days. These data suggest that antioxidants reduce lipid oxidation regardless of light temperature. Antioxidants can still be used to extend shelf life and improve color stability in ground products