Nucleus: A Pilot Project

Early in 2016, an environmental scan was conducted by the Research Library Data Working Group for three purposes: 1.) Perform a survey of the data management landscape at Los Alamos National Laboratory in order to identify local gaps in data management services. 2.) Conduct an environmental scan of external institutions to benchmark budgets, infrastructure, and personnel dedicated to data management. 3.) Draft a research data infrastructure model that aligns with the current workflow and classification restrictions at Los Alamos National Laboratory. This report is a summary of those activities and the draft for a pilot data management project.Comment: 13 pages, repor

Continuous alcoholic fermentation in high cell density airlift bioreactor using flocculating yeast

European Community (EC) - Improving Human Research Potential - contract number MCFI-2001-01504

The Czech adaptation of the Klein et al’s unidimensional targer-neutral scale of commitment

This study describes the process of translating, adapting and validating the Klein et al’s Unidimensional Target-neutral Scale of Commitment (KUT) into Czech. The KUT scale is a self-report scale that consists of four items. The scale was adapted using three independent translations into Czech, one back-translation into English by a native speaker, assessment by experts, and piloting in cognitive interviews with 13 respondents. The study also provides evidence on the scale’s reliability and validity for measuring organizational commitment defined as a psychological bond with an organization. The analyses were based on data obtained from 811 Czech-speaking adults working for Czech organizations. Using ordinal structural equation models (SEM) estimated on the polychoric correlation matrices with the robust WLSMV estimator, the Czech adaptation of the KUT scale showed similar psychometric characteristics to the original English version. The Czech KUT scale is unidimensional and internally consistent. All items have high factor loadings. The scale is invariant across groups defined by gender, workload and the sector in which the organization operates. The convergent validity is supported by the fact that the organizational commitment measured by the Czech KUT scale relates positively to job satisfaction, self-rating of job performance, extra-role behaviour and negatively to turnover intention. The Czech KUT scale also proved incremental validity to job performance over job satisfaction measured by Job Descriptive Survey. Therefore, the scale is a valid instrument for measuring organizational commitment within the Czech-speaking population. It can be used for organizational surveys as well as for research within the organizations

Hydrodynamic analysis of a continuous airlift bioreactor with flocculating high cell density system

One of the most common ways to improve the productivity of a fermentation process is the use of high cell density systems. In practice, such a system usually represents a threephase (gas-liquid-solid) dispersion operating in a continuous mode. The interest for these biosystems has been increasing because they seem to be a very promising alternative to the traditional batch fermentation with freely suspended cells. The cells are usually immobilised on a carrier or in a simpler and cheaper way, they are self-aggregated forming flocs. High cell density biosystems have many specific advantages: higher volumetric productivity, higher product concentration and substrate conversion, easy separation of biocatalyst (cells) from the liquid medium, utilization of the same biocatalyst (cells) for extended periods of process time and a minimised risk of contamination. A continuous airlift bioreactor (CALR) due to the advantageous combination of sufficient mixing, low shear stress and satisfactory flocs suspension at low power input is being often chosen for carrying out fermentations with high cell density. However, there is still a lack of reliable data on transport phenomena, which would allow bioreactor design and scale-up procedures to optimise a bioprocess performance at any bioreactor scale. In airlift bioreactors with a well-defined liquid circulation loop, the liquid velocity is the major hydrodynamic parameter, which considerably affects all physical phenomena. Most velocity measurement techniques are not suitable for use in fermentation processes (e.g. tagging of liquid elements with chemicals due to their interference with the exactly defined substrate pool and sterility problems, visual techniques as Laser Doppler Anemometry due to the opaqueness of the broth). The use of small flowfollowing particles with non-invasive detection of their movement is one of the promising methods. Detection techniques for opaque media include the use of radioactive counters, inductive coils and radio wave detectors. One of the attractive possibilities for a utilization of high cell density system is alcoholic fermentation of lactose from cheese whey using flocculating yeast. Cheese whey, as a by-product of dairy industry, represents a significant environmental problem due to very high values of BOD and COD. For this purpose, a flocculating recombinant strain of Sacharomyces cerevisae was developed enabling the hydrolysis of lactose to galactose and glucose, followed by sugar conversion into ethanol. The main goal of this study was to investigate the hydrodynamics of continuous airlift bioreactor during ethanolic fermentation using highly flocculating yeast. The magnetic particle-tracer method was used for hydrodynamic measurements. Different operation conditions (dilution and air flow rates and biomass concentration), bioreactor configuration and its scale (6 and 50 dm3) have been applied in order to assess their impact on bioreactor hydrodynamics and its operation and to study scale-up effects on the bioprocess. Measurements of liquid circulation velocity revealed one very important fact regarding to airlift bioreactor operation with high cell density system – the existence of a critical value of biomass concentration, at which a dramatic deceleration of net liquid flow appears when the biomass quantity increases (see Figure). Moreover, the magnitude of critical biomass concentration was found not to be dependent on gas flow rate.Marie Curie Fellowship of the European Community - Programme Improving Human Research Potential, Contract number HPMF-CT-2002-01643

Continuous flocculation airlift bioreactor with high cell loading : hydrodynamic and rheological aspects

European Community programme Improving Human Research Potential

Kinetics of lactose fermentation using recombinant saccharomyces cerevisiae

Slovak Scientific Grand Agency; FCT

Polyconvex anisotropic hyperelasticity with neural networks

In the present work, two machine learning based constitutive models for finite deformations are proposed. Using input convex neural networks, the models are hyperelastic, anisotropic and fulfill the polyconvexity condition, which implies ellipticity and thus ensures material stability. The first constitutive model is based on a set of polyconvex, anisotropic and objective invariants. The second approach is formulated in terms of the deformation gradient, its cofactor and determinant, uses group symmetrization to fulfill the material symmetry condition, and data augmentation to fulfill objectivity approximately. The extension of the dataset for the data augmentation approach is based on mechanical considerations and does not require additional experimental or simulation data. The models are calibrated with highly challenging simulation data of cubic lattice metamaterials, including finite deformations and lattice instabilities. A moderate amount of calibration data is used, based on deformations which are commonly applied in experimental investigations. While the invariant-based model shows drawbacks for several deformation modes, the model based on the deformation gradient alone is able to reproduce and predict the effective material behavior very well and exhibits excellent generalization capabilities. In addition, the models are calibrated with transversely isotropic data, generated with an analytical polyconvex potential. For this case, both models show excellent results, demonstrating the straightforward applicability of the polyconvex neural network constitutive models to other symmetry groups

Timelike self-similar spherically symmetric perfect-fluid models

Einstein's field equations for timelike self-similar spherically symmetric perfect-fluid models are investigated. The field equations are rewritten as a first-order system of autonomous differential equations. Dimensionless variables are chosen in such a way that the number of equations in the coupled system is reduced as far as possible and so that the reduced phase space becomes compact and regular. The system is subsequently analysed qualitatively using the theory of dynamical systems.Comment: 23 pages, 6 eps-figure

A Statistical Mechanical Problem in Schwarzschild Spacetime

We use Fermi coordinates to calculate the canonical partition function for an ideal gas in a circular geodesic orbit in Schwarzschild spacetime. To test the validity of the results we prove theorems for limiting cases. We recover the Newtonian gas law subject only to tidal forces in the Newtonian limit. Additionally we recover the special relativistic gas law as the radius of the orbit increases to infinity. We also discuss how the method can be extended to the non ideal gas case.Comment: Corrected an equation misprint, added four references, and brief comments on the system's center of mass and the thermodynamic limi