Guidance and maneuver analyzer Patent

Guidance analyzer having suspended spacecraft simulating sphere for astronavigatio

Uniform electron gases: III. Low-density gases on three-dimensional spheres

By combining variational Monte Carlo (VMC) and complete-basis-set limit Hartree-Fock (HF) calculations, we have obtained near-exact correlation energies for low-density same-spin electrons on a three-dimensional sphere (3-sphere), i.e.~the surface of a four-dimensional ball. In the VMC calculations, we compare the efficacies of two types of one-electron basis functions for these strongly correlated systems, and analyze the energy convergence with respect to the quality of the Jastrow factor. The HF calculations employ spherical Gaussian functions (SGFs) which are the curved-space analogs of cartesian Gaussian functions. At low densities, the electrons become relatively localized into Wigner crystals, and the natural SGF centers are found by solving the Thomson problem (i.e. the minimum-energy arrangement of $n$ point charges) on the 3-sphere for various values of $n$. We have found 11 special values of $n$ whose Thomson sites are equivalent. Three of these are the vertices of four-dimensional Platonic solids --- the hyper-tetrahedron ($n=5$), the hyper-octahedron ($n=8$) and the 24-cell ($n=24$) --- and a fourth is a highly symmetric structure ($n=13$) which has not previously been reported. By calculating the harmonic frequencies of the electrons around their equilibrium positions, we also find the first-order vibrational corrections to the Thomson energy.Comment: 6 pages, 2 figures, accepted for publication in the Journal of Chemical Physic

Introduction to Engineering: Embry-Riddle Aeronautical University EGR101 9th Edition

“Introduction to Engineering” is about making our students at Embry-Riddle Aeronautical University successful in academia and responsible engineering professionals. The collective knowledge of several authors representing all departments within the College of Engineering went into its making. Topics were chosen especially for students in the engineering programs at ERAU to specifically address their needs and tailored to assure their success.https://commons.erau.edu/oer-textbook/1003/thumbnail.jp

Determination of S17(0) from published data

The experimental landscape for the 7Be+p radiative capture reaction is rapidly changing as new high precision data become available. We present an evaluation of existing data, detailing the treatment of systematic errors and discrepancies, and show how they constrain the astrophysical S factor (S17), independent of any nuclear structure model. With theoretical models robustly determining the behavior of the sub-threshold pole, the extrapolation error can be reduced and a constraint placed on the slope of S17. Using only radiative capture data, we find S17(0) = 20.7 +/- 0.6 (stat) +/- 1.0 (syst) eV b if data sets are completely independent, while if data sets are completely correlated we find S17(0) = 21.4 +/- 0.5 (stat) +/- 1.4 (syst) eV b. The truth likely lies somewhere in between these two limits. Although we employ a formalism capable of treating discrepant data, we note that the central value of the S factor is dominated by the recent high precision data of Junghans et al., which imply a substantially higher value than other radiative capture and indirect measurements. Therefore we conclude that further progress will require new high precision data with a detailed error budget.Comment: 10 pages, 1 figure published versio

The Go Clean Cup

Single-serve coffee machines and pods have gained popularity in recent years for ease of use. While these machines can save energy and water in the long run, especially in business settings, the consequences include billions of disposable coffee pods being thrown into landfills around the world each year. Although companies, such as Keurig®, have made reusable pods to fix this problem, the current designs are incompatible with many machines and they use hard plastic, making them difficult to clean. According to a survey conducted by the Go Clean Cup project, 63% of consumers would buy a new reusable single-serve coffee pod of equal price as the others if it was easier to clean. The Go Clean Cup is a reusable single-serve coffee pod that is flexible and eversible for easy cleaning. The pod can be partially or completely everted for coffee grounds to be wiped out without hassle and will be universally compatible with single-serve beverage machines. With a pending utility patent on the design, the Go Clean Cup project is currently focused on developing the best manufacturing method, including molding and laser drilling, to get the product on retail shelves for the lowest cost

Quarantine alone or in combination with other public health measures to control COVID-19: A rapid Cochrane review

In March 2020, the South African government implemented various non-pharmacological prevention and control measures (e.g. isolation, social distancing and quarantine) in response to the COVID-19 pandemic. We summarise evidence from a rapid Cochrane review on the effect of quarantine alone v. quarantine plus combination measures to prevent transmission of and mortality caused by COVID-19. The findings show that when started earlier, quarantine combined with other prevention and control measures can be more effective than quarantine alone, and cost less

Hindrance of Heavy-ion Fusion at Extreme Sub-Barrier Energies in Open-shell Colliding Systems

The excitation function for the fusion-evaporation reaction 64Ni+100Mo has been measured down to a cross-section of ~5 nb. Extensive coupled-channels calculations have been performed, which cannot reproduce the steep fall-off of the excitation function at extreme sub-barrier energies. Thus, this system exhibits a hindrance for fusion, a phenomenon that has been discovered only recently. In the S-factor representation introduced to quantify the hindrance, a maximum is observed at E_s=120.6 MeV, which corresponds to 90% of the reference energy E_s^ref, a value expected from systematics of closed-shell systems. A systematic analysis of Ni-induced fusion reactions leading to compound nuclei with mass A=100-200 is presented in order to explore a possible dependence of the fusion hindrance on nuclear structure.Comment: 10 pages, 9 figures, Submitted to Phys. Rev.

Rooibos (Aspalathus linearis) and its Major Flavonoids — Potential Against Oxidative Stress-Induced Conditions

Reactive species are products of normal cellular metabolism and may be deleterious or beneficial. At low/moderate concentrations, reactive species are involved in physiological roles including cell signalling, defense against infectious agents and mitogenic responses. However, unbalanced defense mechanism of antioxidants, overproduction of reactive species or incorporation of free radicals into the living system from the environment may result in oxidative stress, a deleterious process that can lead to damage of important cell structures, including lipids and membranes, proteins and nucleic acids. The role of oxidative stress as a contributing factor in the pathophysiology of various diseases is increasingly being recognized, and augmenting the oxidative defense capacity of the cell through the intake of antioxidants as a way of preventing free radical-mediated cellular injuries is becoming a popular strategy. Much attention is being focused on the health beneficial role of phenolic phytochemicals derived from plants. They are considered to play an important role as physiologically functional foods and for the prevention of clinical conditions related to oxidative stress, even though their modes of action may still not be fully understood. Rooibos (Aspalathus linearis) is a popular South African tisane enjoyed for its taste and aroma. Rooibos has been made in the Cederberg mountain region of South Africa for generations and has been used medicinally for alleviation of allergies, asthma, infantile colic and skin problems. The potential antioxidative, immune-modulating, chemopreventive and chemotherapeutic actions of rooibos have been reported in several studies. This review provides a comprehensive data on the current knowledge of the biological and chemotherapeutic activity of rooibos and its major flavonoids. Most recent in vitro and in vivo (animal and human) studies were conducted with special attention paid to clinical conditions in which oxidative stress has been implicated. The conclusion described directions for future rooibos research to establish its activity and utility as a human chemopreventive and therapeutic agent

Manipulating task constraints shapes emergence of herding tendencies in team games performance

The herding phenomenon is observed in nature and has been perceived to be less desirable use of space in impacting overall team play performance. The effective manipulating of rules and task constraints might be able to alter herding tendencies in sport performance. The aim of this study was to determine the impact of altering task constraints on herding tendencies, measured with the use of cluster phase analysis, which has also been used to analyse the synchrony exhibited by performers in invasion games such as professional association football matches. In this study, tracking positional data of individual players in a simulated pass and catch game was undertaken, with no specific verbal instructions provided to participants on how and where to move so that emergent behavioural tendencies could be observed. Data revealed how task constraint manipulations impacted on herding tendencies. Manipulation of task constraints revealed higher levels of clustering tendencies in the herding condition compared to, the non-herding condition. Within the herding condition, between-team synchrony was also strong, especially in the longitudinal direction. Ball possession also seemed to have some impact on within-team synchrony. Findings provided preliminary evidence on how manipulating task constraints can be effective in altering herding tendencies in team games