2,145 research outputs found

    Soil mechanics on the Moon, Mars, and Mulberry

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    From a soil mechanics point of view, the Moon is a relatively simple place. Without any water, organics, or clay minerals, the geotechnical properties of the lunar soil are confined to a fairly limited range. Furthermore, the major soil-forming agent is meteorite impact, which breaks the big particles into little particles; and simultaneously, cements the little particles back together again with molten glass. After about a hundred million years of exposure to meteorite impact, the distribution of particle sizes in the soil achieves a sort of steady state. The majority of the returned lunar soil samples have been found to be well-graded silty-sand to sandy-silt (SM in the Unified Soil Classification System). Each of the particle size distributions plots within a relatively narrow band, which appears to be uniform over the entire lunar surface. This further restricts the range of physical properties of the lunar surface. In contrast, Martian soils should exhibit an extremely wide range of properties. We already know that there is a small amount of water in the soil, greater than in the Martian atmosphere. Furthermore, the soil is suspected to be smectitic clay. That makes two out of the three factors that greatly affect the properties of terrestrial soils

    Reformulation of the Stochastic Potential Switching Algorithm and a Generalized Fourtuin-Kasteleyn Representation

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    A new formulation of the stochastic potential switching algorithm is presented. This reformulation naturally leads us to a generalized Fourtuin-Kasteleyn representation of the partition function Z. A formula for internal energy E and that of heat capacity C are derived from derivatives of the partition function. We also derive a formula for the exchange probability in the replica exchange Monte Carlo method. By combining the formulae with the Stochastic Cutoff method, we can greatly reduce the computational time to perform internal energy and heat capacity measurements and the replica exchange Monte Carlo method in long-range interacting systems. Numerical simulations in three dimensional magnetic dipolar systems show the validity and efficiency of the method.Comment: 11 pages, 6 figures, to appear in PR

    Data Analysis Processes and Techniques for Validation of Wearable Technology: An Example

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    Topics in Exercise Science and Kinesiology Volume 3: Issue 1, Article 10, 2022. With wearable technology growing in popularity and sophistication, there remains a need to determine the validity of these devices by independent observers. Validation studies of wearable technology can involve large amounts of data, with data preparation techniques that are not always clearly established. This can make attempts to reproduce the results difficult and does not allow researchers to gain guidance in how to perform their own analyses if they wanted to perform a similar study. Therefore, this paper details the process that was utilized to prepare and analyze the accuracy of several heart rate monitors during mountain biking and can be used as a possible guide to researchers looking to perform similar analyses. We also detail the software used and discuss possible alternatives

    Note on the dynamics of the Gulf Stream

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    The nonlinear inertial terms have been neglected in Stommel\u27s and in Munk\u27s theory for the wind-driven ocean circulation. Using a method of successive approximations, the effect of these terms on the mass transport in the Gulf Stream region has been computed under greatly simplifying assumptions. These assumptions involve Reid\u27s model of the vertical density structure, which consists of an exponential decrease in the density upward to the thermocline and a homogeneous upper layer...

    Analysis of complex singularities in high-Reynolds-number Navier-Stokes solutions

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    Numerical solutions of the laminar Prandtl boundary-layer and Navier-Stokes equations are considered for the case of the two-dimensional uniform flow past an impulsively-started circular cylinder. We show how Prandtl's solution develops a finite time separation singularity. On the other hand Navier-Stokes solution is characterized by the presence of two kinds of viscous-inviscid interactions that can be detected by the analysis of the enstrophy and of the pressure gradient on the wall. Moreover we apply the complex singularity tracking method to Prandtl and Navier-Stokes solutions and analyze the previous interactions from a different perspective

    The Dryad Repository Application Profile: Process, Development, and Refinement

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    This paper presents research and development work for the Dryad metadata application profile. Dryad is a digital repository for datasets underlying published works in evolutionary biology and related fields. The paper details the phased implementation of the repository and the corresponding modular application profile. The paper reviews the application profile methodology, reviews each element description, and describes how the schema supports the unique functionalities of each phase of Dryad. The approach presents a method for bringing the Level One application profile, which is currently being tested for Phase One of Dryad, into conformance with the Dublin Core Singapore Framework. The benefits of compliance with the Singapore Framework include maximum interoperability and long-term quality control of the schema. In addition, conformance will allow for the Dryad application profile to be utilized by other initiatives. Finally, this paper proposes a Level Two Dryad application profile and a means of implementation

    Oscillating red giants in the CoRoT exo-field: Asteroseismic mass and radius determination

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    Context. Observations and analysis of solar-type oscillations in red-giant stars is an emerging aspect of asteroseismic analysis with a number of open questions yet to be explored. Although stochastic oscillations have previously been detected in red giants from both radial velocity and photometric measurements, those data were either too short or had sampling that was not complete enough to perform a detailed data analysis of the variability. The quality and quantity of photometric data as provided by the CoRoT satellite is necessary to provide a breakthrough in observing p-mode oscillations in red giants. We have analyzed continuous photometric time-series of about 11 400 relatively faint stars obtained in the exofield of CoRoT during the first 150 days long-run campaign from May to October 2007. We find several hundred stars showing a clear power excess in a frequency and amplitude range expected for red-giant pulsators. In this paper we present first results on a sub-sample of these stars. Aims. Knowing reliable fundamental parameters like mass and radius is essential for detailed asteroseismic studies of red-giant stars. As the CoRoT exofield targets are relatively faint (11-16 mag) there are no (or only weak) constraints on the star's location in the H-R diagram. We therefore aim to extract information about such fundamental parameters solely from the available time series. Methods. We model the convective background noise and the power excess hump due to pulsation with a global model fit and deduce reliable estimates for the stellar mass and radius from scaling relations for the frequency of maximum oscillation power and the characteristic frequency separation.Comment: 10 pages, 7 figures, accepted for publication in A&

    Establishing a Methodology for Conducting a Rapid Review on Wearable Technology Reliability and Validity in Applied Settings

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    Wearable technology is becoming increasingly popular with new devices entering the market frequently, but with disproportionality less research being conducted on the reliability and validity in field settings, outside of the laboratory. This paper details the methodology of gathering research based on the principals of a rapid review, using these points of application: inclusion criteria of studies (databases), search terms (data to be extracted), and how research will be conducted (narrowing articles and assessing bias). Point of application #1: Inclusion criteria are described well as potential databases used, allowing a means of not only systematically gathering information, but also the ability to check the status of the literature regarding wearable technology. Point of application #2: Specific search terms are outlined, and the data fields to be extracted are described. Point of application #3: Mechanism of the rapid review search explained, how articles are to be included and excluded, and how bias will be assessed
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