5,108 research outputs found
Evaluation and characterization of the methane-carbon dioxide decomposition reaction
A program was conducted to evaluate and characterize the carbon dioxide-methane (CO2-CH4) decomposition reaction, i.e., CO2 + CH4 = 2C + 2H2O. The primary objective was to determine the feasibility of applying this reaction at low temperatures as a technique for recovering the oxygen (O2) remaining in the CO2 which exits mixed with CH4 from a Sabatier CO2 reduction subsystem (as part of an air revitalization system of a manned spacecraft). A test unit was designed, fabricated, and assembled for characterizing the performance of various catalysts for the reaction and ultraviolet activation of the CH4 and CO2. The reactor included in the test unit was designed to have sufficient capacity to evaluate catalyst charges of up to 76 g (0.17 lb). The test stand contained the necessary instrumentation and controls to obtain the data required to characterize the performance of the catalysts and sensitizers tested: flow control and measurement, temperature control and measurement, product and inlet gas analysis, and pressure measurement. A product assurance program was performed implementing the concepts of quality control and safety into the program effort
The Early Days of Research on Carbonic Anhydrase
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73862/1/j.1749-6632.1984.tb12310.x.pd
An exact study of charge-spin separation, pairing fluctuations and pseudogaps in four-site Hubbard clusters
An exact study of charge-spin separation, pairing fluctuations and pseudogaps
is carried out by combining the analytical eigenvalues of the four-site Hubbard
clusters with the grand canonical and canonical ensemble approaches in a
multidimensional parameter space of temperature (T), magnetic field (h),
on-site interaction (U) and chemical potential. Our results, near the average
number of electrons =3, strongly suggest the existence of a critical
parameter U_{c}(T) for the localization of electrons and a particle-hole
binding (positive) gap at U>U_{c}(T), with a zero temperature quantum critical
point, U_{c}(0)=4.584. For U<U_{c}(T), particle-particle pair binding is found
with a (positive) pairing gap. The ground state degeneracy is lifted at
U>U_c(T) and the cluster becomes a Mott-Hubbard like insulator due to the
presence of energy gaps at all (allowed) integer numbers of electrons. In
contrast, for U< U_c(T), we find an electron pair binding instability at finite
temperature near =3, which manifests a possible pairing mechanism, a
precursor to superconductivity in small clusters.
In addition, the resulting phase diagram consisting of charge and spin
pseudogaps, antiferromagnetic correlations, hole pairing with competing
hole-rich (=2), hole-poor (=4) and magnetic (=3) regions in the
ensemble of clusters near 1/8 filling closely resembles the phase diagrams and
inhomogeneous phase separation recently found in the family of doped high T_c
cuprates.Comment: 10 pages, 7 figure
A Factorization Algorithm for G-Algebras and Applications
It has been recently discovered by Bell, Heinle and Levandovskyy that a large
class of algebras, including the ubiquitous -algebras, are finite
factorization domains (FFD for short).
Utilizing this result, we contribute an algorithm to find all distinct
factorizations of a given element , where is
any -algebra, with minor assumptions on the underlying field.
Moreover, the property of being an FFD, in combination with the factorization
algorithm, enables us to propose an analogous description of the factorized
Gr\"obner basis algorithm for -algebras. This algorithm is useful for
various applications, e.g. in analysis of solution spaces of systems of linear
partial functional equations with polynomial coefficients, coming from
. Additionally, it is possible to include inequality constraints
for ideals in the input
Big data-savvy teams’ skills, big data-driven actions and business performance
Prior studies on big data analytics have emphasized the importance of specific big data skills and capabilities for organizational success; however, they have largely neglected to investigate the use of cross-functional teams’ skills and its links to the role played by relevant data-driven actions and business performance. Drawing on the resource-based view (RBV) of the firm and on the data collected from big data experts working in global agrifood networks, we examine the links between the use of big data-savvy (BDS) teams’ skills, big data-driven (BDD) actions and business performance. BDS teams depend on multidisciplinary skills (e.g., computing, mathematics, statistics, machine learning, and business domain knowledge) that help them to turn their traditional business operations into modern data-driven insights (e.g., knowing real time price changes and customer preferences), leading to BDD actions that enhance business performance. Our results, raised from structural equation modelling, indicate that BDS teams' skills that produce valuable insights are the key determinants for BDD actions, which ultimately contribute to business performance. We further demonstrate that those organisations that emphasise BDD actions perform better compared to those that do not focus on such applications and relevant insights
Noise resistance of adiabatic quantum computation using random matrix theory
Besides the traditional circuit-based model of quantum computation, several
quantum algorithms based on a continuous-time Hamiltonian evolution have
recently been introduced, including for instance continuous-time quantum walk
algorithms as well as adiabatic quantum algorithms. Unfortunately, very little
is known today on the behavior of these Hamiltonian algorithms in the presence
of noise. Here, we perform a fully analytical study of the resistance to noise
of these algorithms using perturbation theory combined with a theoretical noise
model based on random matrices drawn from the Gaussian Orthogonal Ensemble,
whose elements vary in time and form a stationary random process.Comment: 9 pages, 3 figure
Sums of two squares and a power
We extend results of Jagy and Kaplansky and the present authors and show that
for all there are infinitely many positive integers , which cannot
be written as for positive integers , where for
a congruence condition is imposed on . These
examples are of interest as there is no congruence obstruction itself for the
representation of these . This way we provide a new family of
counterexamples to the Hasse principle or strong approximation.Comment: 6 pages, to appear in the memorial volume "From Arithmetic to
Zeta-Functions - Number Theory in Memory of Wolfgang Schwarz
NMR experiment factors numbers with Gauss sums
We factor the number 157573 using an NMR implementation of Gauss sums.Comment: 4 pages 5 figure
Thermal noise limitations to force measurements with torsion pendulums: Applications to the measurement of the Casimir force and its thermal correction
A general analysis of thermal noise in torsion pendulums is presented. The
specific case where the torsion angle is kept fixed by electronic feedback is
analyzed. This analysis is applied to a recent experiment that employed a
torsion pendulum to measure the Casimir force. The ultimate limit to the
distance at which the Casimir force can be measured to high accuracy is
discussed, and in particular the prospects for measuring the thermal correction
are elaborated upon.Comment: one figure, five pages, to be submitted to Phys Rev
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