3,026 research outputs found
Mass transfer in the electrodialytic desalination of brackish water and a correlation of experimental data with theory
The object of this work is an experimental investigation into the possibility of obtaining an increase in mass transfer in the electrodialysis of brackish water by altering the physical character of the selective membrane, and a correlation of experimental mass transfer data with theory --Introduction, page 1
Deployment Architectures for Cyber-Physical Control Systems
We consider the problem of how to deploy a controller to a (networked) cyber-physical system (CPS). Controlling a CPS is an involved task, and synthesizing a controller to respect sensing, actuation, and communication constraints is only part of the challenge. In addition to controller synthesis, one should also consider how the controller will work in the CPS. Put another way, the cyber layer and its interaction with the physical layer need to be taken into account.In this work, we aim to bridge the gap between theoretical controller synthesis and practical CPS deployment. We adopt the system level synthesis (SLS) framework to synthesize a state-feedback controller and provide a deployment architecture for the standard SLS controller. Furthermore, we derive a new controller realization for open-loop stable systems and introduce four different architectures for deployment, ranging from fully centralized to fully distributed. Finally, we compare the trade-offs among them in terms of robustness, memory, computation, and communication overhead
Exact Conditional Inference for Two-way Randomized Bernoulli Experiments
Exact conditional inference for two-way randomized experiments with Bernoulli-distributed outcomes is a useful special case of exact logistic regression, but unlike the general case, it is trivial to compute. We present an R function which can easily be translated into any other language, making this type of analysis more readily accessible
Quantum dynamics of molecular multiphoton excitation in intense laser and static electric fields: Floquet theory, quasienergy spectra, and application to the HF molecule
This is the published version, also available here: http://dx.doi.org/10.1063/1.444219.The multiphoton excitationdynamics of vibration‐rotation states in diatomic molecules in intense laser and static electric fields is investigated. The Floquet matrix method is used to calculate the quasienergy and multiphoton absorptionspectra of the HF molecule as functions of field strengths and frequency. Nonlinear effects such as power broadening, dynamic Stark shift, Autler–Townes multiplet splitting, hole burning, and S‐hump behaviors, etc., are observed and discussed in terms of quasienergy diagrams. Many of the salient features in the spectral line shapes may be qualitatively understood in terms of an analytical three‐level model. The addition of a dc electric field removes the restriction of the rotational dipole selection rule and causes significant intermixing of the bare molecular vibrator states. Due to the greater number of strongly coupled nearby states in the dc field, nonlinear effects such as those mentioned above appear at a much lower ac field strength than they would in the absence of the dc field. The introduction of an external dc field, therefore, strongly enhances the multiphoton excitation probabilities and results in a much richer spectrum
Evolution of Phototrophy in the Chloroflexi Phylum Driven by Horizontal Gene Transfer
The evolutionary mechanisms behind the extant distribution of photosynthesis is a point of substantial contention. Hypotheses range from the presence of phototrophy in the last universal common ancestor and massive gene loss in most lineages, to a later origin in Cyanobacteria followed by extensive horizontal gene transfer into the extant phototrophic clades, with intermediate scenarios that incorporate aspects of both end-members. Here, we report draft genomes of 11 Chloroflexi: the phototrophic Chloroflexia isolate Kouleothrix aurantiaca as well as 10 genome bins recovered from metagenomic sequencing of microbial mats found in Japanese hot springs. Two of these metagenome bins encode photrophic reaction centers and several of these bins form a metabolically diverse, monophyletic clade sister to the Anaerolineae class that we term Candidatus Thermofonsia. Comparisons of organismal (based on conserved ribosomal) and phototrophy (reaction center and bacteriochlorophyll synthesis) protein phylogenies throughout the Chloroflexi demonstrate that two new lineages acquired phototrophy independently via horizontal gene transfer (HGT) from different ancestral donors within the classically phototrophic Chloroflexia class. These results illustrate a complex history of phototrophy within this group, with metabolic innovation tied to HGT. These observations do not support simple hypotheses for the evolution of photosynthesis that require massive character loss from many clades; rather, HGT appears to be the defining mechanic for the distribution of phototrophy in many of the extant clades in which it appears
Diffusion due to the Beam-Beam Interaction and Fluctuating Fields in Hadron Colliders
Random fluctuations in the tune, beam offsets and beam size in the presence
of the beam-beam interaction are shown to lead to significant particle
diffusion and emittance growth in hadron colliders. We find that far from
resonances high frequency noise causes the most diffusion while near resonances
low frequency noise is responsible for the large emittance growth observed.
Comparison of different fluctuations shows that offset fluctuations between the
beams causes the largest diffusion for particles in the beam core.Comment: 5 pages, 3 postscript figure
Scalable scheme for entangling multiple ququarts using linear optical elements
We report a scalable linear optical scheme for generating entangled states of
multiple ququarts in which the individual single-ququart state is prepared with
the biphoton polarization state of frequency-nondegenerate spontaneous
parametric down-conversion. The output state is calculated with the full
consideration of the higher order effect (double-pair events) of spontaneous
parametric down-conversion. Scalability to multiple-ququart entanglement is
demonstrated with examples: linear optical entanglement of three and four
individual biphoton ququarts
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