In The Afterglow

https://digitalcommons.library.umaine.edu/mmb-vp/5031/thumbnail.jp

A foundation model for atomistic materials chemistry

Machine-learned force fields have transformed the atomistic modelling of materials by enabling simulations of ab initio quality on unprecedented time and length scales. However, they are currently limited by: (i) the significant computational and human effort that must go into development and validation of potentials for each particular system of interest; and (ii) a general lack of transferability from one chemical system to the next. Here, using the state-of-the-art MACE architecture we introduce a single general-purpose ML model, trained on a public database of 150k inorganic crystals, that is capable of running stable molecular dynamics on molecules and materials. We demonstrate the power of the MACE-MP-0 model - and its qualitative and at times quantitative accuracy - on a diverse set problems in the physical sciences, including the properties of solids, liquids, gases, chemical reactions, interfaces and even the dynamics of a small protein. The model can be applied out of the box and as a starting or "foundation model" for any atomistic system of interest and is thus a step towards democratising the revolution of ML force fields by lowering the barriers to entry.Comment: 119 pages, 63 figures, 37MB PD

Hybridization and its application in aquaculture

Inter‐specific hybrids are usually formed by mating two different species in the same genus. They have been produced to increase growth rate, improve production performance, transfer desirable traits, reduce unwanted reproduction, combine other valuable traits such as good flesh quality, disease resistance and increase environmental tolerances, better feed conversion, and increase harvesting rate in culture systems. Hybrids play a significant role in helping to increase aquaculture production of several species of freshwater and marine fishes – for example, hybrid catfish in Thailand, hybrid striped bass in the USA, hybrid tilapia in Israel, and hybrid characids in Venezuela. As the domestication of fish species increases, the possibilities to increase production through appropriate hybridization techniques are ongoing, with a view to produce new hybrid fishes, especially in culture systems where sterile fish may be preferred because of the concern that fish may escape into the open freshwater, marine and coastal environment. Intentional or accidental hybridization can lead to unexpected results in hybrid progeny, such as reduced viability and growth performances, loss of color pattern and flesh quality, and it also raises risks for maintenance of genetic integrity. Appropriate knowledge on the genetic constitution of the brood stock, proper brood stock management, and monitoring of the viability and fertility of the progeny of brood fishes, is thus very crucial before initiating hybridization experiments. In addition, some non‐generic factors, such as weather conditions, culture systems, seasons, and stresses associated with selecting, collecting, handling, breeding and rearing of brood stock and progeny, may influence hybridization success in a wide variety of freshwater and marine fin fishes to a greater extent

Two-axis haptic force feedback joystick

Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.Cataloged from PDF version of thesis.Includes bibliographical references (pages 46-47).The development of multi-axis force feedback joysticks enables mechanically coupled systems to be recreated by electronically coupled systems. A study of haptic force feedback systems was performed. A four-arm joint mechanism was designed and developed to enable multi-axis haptic force feedback. The joint mechanism was manufactured and preliminary validation experiments were performed. It was found that the joint mechanism accurately transmits forces proportional to the current applied to each drive motor and that the joystick mechanism developed in this thesis can be further validated and developed for specific applications of haptic force feedback.by Will Pritchett.S.B

Soil Outreach in the Local Community

Kristin Moretz, a founder of the soil outreach program, teaches children at the UT Farmer\u27s Market the importance of soil conservation in hopes to mold the minds of future soil scientists.https://trace.tennessee.edu/utiaphoto_2015/1050/thumbnail.jp

More Than Just Mud

Taken in Doylestown, Pennsylvania, where soil judger Kristin Moretz braves the cold and mud to get soil samples and identifies horizon breaks to further understand the pit characteristics.https://trace.tennessee.edu/utiaphoto_2015/1026/thumbnail.jp

Climate, vegetation phenology and forest fires in Siberia

A time series of 18 years of fAPAR (fraction of photosynthetically active radiation absorbed by the green parts of vegetation) data from the NOAA AVHRR instrument series was analyzed for interannual variations in the start, peak, end and length of the season of vegetation photosynthetic activity in Central and East Siberia. Variations in these indicators of seasonality can give important information on interactions between the biosphere and atmosphere. A second order local moving window regression model called the “camel back method” was developed to determine the dates of phenological events at subcontinental scale. The algorithm was validated by comparing the estimated dates to phenological field observations. Using spatial correlations with temperature and recipitation data and climatic oscillation indices, we postulate two geographically distinct mechanisms in the system of climatic controls of the biosphere in Siberia: Central Siberia is controlled by an “Arctic Oscillation/temperature mechanism” while East Siberia is controlled by an “El Niño/precipitation mechanism”. While the analysis of data from 1982 to 1991 indicates a slight increase in the length of the growing season for some land cover types due to an earlier beginning of the growing season, the overall trend from 1982 to 1999 is towards a slightly shorter season for some land cover types caused by an earlier end of season. The Arctic Oscillation tended towards a more positive phase in the Eighties leading to enhanced high pressure system prevalence but towards a less positive phase in the Nineties. We suggest that the two mechanisms also control the fire regimes in Central and East Siberia. Several extreme fire years in Central Siberia were associated with a highly positive Arctic Oscillation phase, while several years with high fire damage in East Siberia occurred in El Niño years. An analysis of remote sensing data of forest fire partially supports this hypothesis

Gio Lab: Development of CubeLab Platform for International Space Station Based Biomedical Research

GlioLab is a joint project between Morehead State University, GAUSS-Group of Astrodynamics of the University of Roma, Kentucky Space and the NASA Ames Research Center that involves the development of a 2U CubeLab (GlioLab). The primary objectives of the project are to develop a CubeLab platform for performing biomedical research on the International Space Station (ISS), and to perform preliminary ground-based and flight experimentation (STS-134 and STS-135) that will help drive the development of GlioLab. The platform will incorporate a liquid mixing apparatus that will allow 2-3 liquids to be mixed and require the development of various additional subsystems to support biological specimens for varying lengths of time while aboard IIS. An automated system will control the injection/mixing of liquids in user-specified ratios and at user-specified times. The platform will utilize small fluid amounts (≤10 ml), which will be exposed to microgravity for a specified length of time and then returned to Earth for analysis. A set of mission profiles have been designed based on available ascent and decent vehicles along with the current mechanisms and logistics related to access to the ISS NanoRacks System. These mission profiles will be used to direct the accompanying ground based research utilizing the Glioblastoma cancer line as its experimental model. The potential for biomedical research utilizing Gliolab onboard the ISS or space flights in general will pave the way for future affordable biomedical research in microgravity and hopefully yield new terrestrial biomedical applications and treatments

Improvements in Aerosol Optical Depth Estimation Using Multiangle CHRIS/PROBA Images

A method has been developed to estimate aerosol optical depth (AOD) over land surfaces using high spatial resolution, hyperspectral, and multiangle Compact High Resolution Imaging Spectrometer (CHRIS)/Project for On Board Autonomy (PROBA) images. The CHRIS instrument is mounted aboard the PROBA satellite and provides up to 62 bands. The PROBA satellite allows pointing to obtain imagery from five different view angles within a short time interval. The method uses inversion of a coupled surface/atmosphere radiative transfer model and includes a general physical model of angular surface reflectance. An iterative process is used to determine the optimum value providing the best fit of the corrected reflectance values for a number of view angles and wavelengths with those provided by the physical model. This method has previously been demonstrated on data from the Advanced Along-Track Scanning Radiometer and is extended here to the spectral and angular sampling of CHRIS/PROBA. The values obtained from these observations are validated using ground-based sun-photometer measurements. Results from 22 image sets show an rms error of 0.11 in AOD at 550 nm, which is reduced to 0.06 after an automatic screening procedure