Miracle-dz/UniFAR-FTUs huggingface dataset:
Chemical identification of new particle formation and growth precursors through positive matrix factorization of ambient ion measurements

Abstract. In the lower troposphere, rapid collisions between ions and trace gases result in the transfer of positive charge to the highest proton affinity species and negative charge to the lowest proton affinity species. Measurements of the chemical composition of ambient ions thus provide direct insight into the most acidic and basic trace gases and their ion–molecule clusters – compounds thought to be important for new particle formation and growth. We deployed an atmospheric pressure interface time-of-flight mass spectrometer (APi-ToF) to measure ambient ion chemical composition during the 2016 Holistic Interactions of Shallow Clouds, Aerosols, and Land Ecosystems (HI-SCALE) campaign at the United States Department of Energy Atmospheric Radiation Measurement facility in the Southern Great Plains (SGP), an agricultural region. Cations and anions were measured for alternating periods of ∼ 24 h over 1 month. We use binned positive matrix factorization (binPMF) and generalized Kendrick analysis (GKA) to obtain information about the chemical formulas and temporal variation in ionic composition without the need for averaging over a long timescale or a priori high-resolution peak fitting. Negative ions consist of strong acids including sulfuric and nitric acid, organosulfates, and clusters of NO3- with highly oxygenated organic molecules (HOMs) derived from monoterpene (MT) and sesquiterpene (SQT) oxidation. Organonitrates derived from SQTs account for most of the HOM signal. Combined with the diel profiles and back trajectory analysis, these results suggest that NO3 radical chemistry is active at this site. SQT oxidation products likely contribute to particle growth at the SGP site. The positive ions consist of bases including alkyl pyridines and amines and a series of high-mass species. Nearly all the positive ions contained only one nitrogen atom and in general support ammonia and amines as being the dominant bases that could participate in new particle formation. Overall, this work demonstrates how APi-ToF measurements combined with binPMF analysis can provide insight into the temporal evolution of compounds important for new particle formation and growth.
A Computer Vision System for Iris Recognition Based on Deep Learning

Biometric systems are playing an important role in identifying a person, thus contributing to global security. There are many possible biometrics, for example height, DNA, handwriting etc., but computer vision based biometrics have found an important place in the domain of human identification. Computer vision based biometrics include identification of face, fingerprints, iris etc. and using their abilities to create efficient authentication systems. In this paper, we work on a dataset [1] of iris images and make use of deep learning to identify and verify the iris of a person. Hyperparameter tuning for deep networks and optimization techniques have been taken into account in this system. The proposed system is trained using a combination of Convolutional Neural Networks and Softmax classifier to extract features from localized regions of the input iris images. This is followed by classification into one out of 224 classes of the dataset. From the results, we conclude that the choice of hyperparameters and optimizers affects the efficiency of our proposed system. Our proposed approach outperforms existing approaches by attaining a high accuracy of 98 percent.
Forming of selected unimodal complex amplitude distributions by means of novel DOEs of MODAN type

We present results of iterative calculation, manufacturing and experimental as well as theoretical investigations of a novel diffractive optical element (DOE) which transforms a Gaussian TEM00 input beam into a unimodal Gauss-Hermite complex distribution. The iterative calculation procedure is based on the application of the method of generalized projections. The projection operator onto a set of modal functions is implemented through partition of the focal plane into a 'useful' and an 'auxiliary' domain. As a result of this calculation there will be a 2D phase distribution which has to be transferred into the optical element. This element has been manufactured as 16 level surface profile by electron-beam direct-writing into a PMMA resist film and a subsequent development procedure of the resist. Each of the generated 15 steps of the resist profile corresponds to a certain electron dose, comparable to a usual 'isobathic process'. The final element consists of a fused silica substrate coated with the structured PMMA film, and has been designed for transmission mode and (lambda) equals 633 nm. Whereas computation results consist in the form of lateral distributions of the complex amplitude in the Fourier-plane, experimental results will be intensity distributions only. To measure additionally the phase distribution, we realized a special interferometric set-up. Both computational and experimental results are presented and demonstrate a good conformity with each other. Energy efficiency has been measured in the Fourier-plane as 37.7 percent, compared with the calculated value of 45 percent. The achieved results show good perspectives of such an approach for the formation and application of unimodal distributions.
Modeling of light generation in photonic crystal lasers

In this paper, we present an analysis of light generation in various lasers based on photonic crystal structures. In our theoretical model, we take into account the gain saturation effect, transverse and longitudinal field distribution. That model allows defining in easy way the influence of the real structures parameters (for example photonic crystal cell geometry) on the normalized small signal gain, spontaneous emission, relaxation oscillation parameters, and 3dB modulation bandwidth.
Regression Methods for Poisson Process Data

Abstract This article is directed toward situations where individuals can experience repeated events, and data on an individual consist of the number and occurrence times of events, along with concomitant variables. Methods of regression analysis are presented, based on Poisson process and proportional intensity assumptions. These include parametric and semi-parametric approaches to model fitting, model assessment, and the treatment of random effects. In addition, insight is gained as to the central role of Poisson and mixed Poisson regression analysis of counts in these methods, and as to the effects of unobserved heterogeneity on semi-parametric analyses. The methods in the article are based on the proportional intensity Poisson process model, for which an individual with given fixed covariate vector x has repeated events occur according to a nonhomogeneous Poisson process with intensity function λx(t) = λ0(t)exp(x′β). Estimation of β and the baseline intensity λ0(t) are considered when λ0(t) is specifi.
Blind navigation using ambient crowd analysis

Research in assistive technology has been on the rise over the last decade. Numerous solutions and consumer products have flooded the market to guide visually impaired making use of beacon technology, depth cameras and many more. Though certain products and solutions are available for highly structured and regular indoor environments, we are still a long way from an industrial level product for unstructured, dynamic and irregular outdoor environments. Our work harnesses the decision making power of sighted individuals and crowd as a group surrounding the visually impaired. This information extraction from the crowd along with coarse terrain mapping of major obstacles like footpath edges, walls and large pot holes will help the subject to navigate dynamic and irregular environments. This out of the box approach provides us the margin to use low grade equipment and develop algorithms with low computational complexity. The paper explains the theoretical aspects of this approach along with its proof of concept and some remarkable results achieved in real life implementation.
Micromagnetic study of spin wave propagation in bicomponent magnonic crystal waveguides

The propagation of spin waves in bicomponent magnonic crystal waveguides has been investigated by micromagnetic simulations. The nanostructured waveguides studied are regular square lattice arrays of circular Fe dots embedded in an yttrium iron garnet matrix. Our simulations show that the waveguides exhibit wide magnonic band gaps of the order of 10 GHz. Band gap tunability, arising from variations in the filling fraction, lattice constant, and applied magnetic field has been demonstrated. Our findings would be of value to the efficient transmission and processing of microwave signals on the nanoscale by means of spin waves.
Enabling unmanned capabilities in the tactical wheeled vehicle fleet of the future

From transporting troops and weapons systems to supplying beans, bullets, and Band-Aids to front-line warfighters, tactical wheeled vehicles serve as the materiel backbone anywhere there are boots on the ground. Drawing from the U.S. Army's Tactical Wheeled Vehicle Strategy and the Marine Corps Vision & Strategy 2025 reports, one may conclude that the services have modest expectations for the introduction of large unmanned ground systems into operational roles in the next 15 years. However, the Department of Defense has already invested considerably in the research and development of full-size UGVs-and commanders deployed in both Iraq and Afghanistan have advocated the urgent fielding of early incarnations of this technology, believing it could make a difference on their battlefields today. For military UGVs to evolve from mere tactical advantages into strategic assets with developed doctrine, they must become as trustworthy as a well-trained warfighter in performing their assigned task. Starting with the Marine Corps' ongoing Cargo Unmanned Ground Vehicle program as a baseline, and informed by feedback from previously deployed subject matter experts, this paper examines the gaps which presently exist in UGVs from a mission-capable perspective. It then considers viable near-term technical solutions to meet today's functional requirements, as well as long-term development strategies to enable truly robust performance. With future conflicts expected to be characterized by increasingly complex operational environments and a broad spectrum of rapidly adapting threats, one of the largest challenges for unmanned ground systems will be the ability to exhibit agility in unpredictable circumstances.
Collisionless reconnection: Effects of Hall current and electron pressure gradient

An analytical treatment is given of two-dimensional, quasi-steady collisionless reconnection on the basis of the generalized Ohm's law, including the effects of the Hall current and scalar electron pressure gradient. The equilibrium magnetic field configuration is of the form , containing a neutral line at z = 0 and a constant guide field BT. The dispersion relations of the waves in the ideal region as well as the reconnection layer are discussed, including the effects of plasma beta. When BT = 0, the reconnection layer supports obliquely propagating Alfven-whistler waves, and the reconnection dynamics is controlled by the Hall current. When BT/BP0 ≥ 1, the reconnection layer supports kinetic/inertial Alfven waves, and the reconnection dynamics is controlled by the electron pressure gradient. Analytical estimates are obtained for the nonlinear reconnection rate with and without the guide field from the generalized Ohm's law. A recent claim by Shay et al. (1999) that the reconnection rate is a “universal constant” is questioned. Although the leading-order reconnection rate is independent of the mechanism that breaks field lines (resistivity or electron inertia) and the system size as the system size becomes large, it does depend on global conditions such as the boundary conditions driving reconnection. The analytical predictions are tested by means of Hall magnetohydrodynamics simulations. While some of the geometric features of the reconnection layer and the weak dependence of the reconnection rate on resistivity are reminiscent of Petschek's classical model, the underlying wave and particle dynamics mediating reconnection in the presence of the Hall current and electron pressure gradient are qualitatively different.
ANALYSIS OF HEAT TRANSFER BETWEEN TWO UNSYMMETRICALLY HEATED PARALLEL PLATES WITH MICROSPACING IN THE SLIP FLOW REGIME

In this article, we present a theoretical analysis for laminar flow and heat transfer between two parallel plates with a microspace under unsymmetrical wall heat flux in the slip flow regime. The momentum and energy equations with the boundary conditions of slip velocity and temperature jump are solved for the hydraulic and thermal fully developed laminar flow of the incompressible fluid in this microchannel. The influences of the Kn number, the tangential momentum accommodation coefficient, and the thermal accommodation coefficient on the temperature profile and the heat transfer characteristics are discussed.
Extended stability region for large bipolarons through interaction with multiple phonon branches

Abstract The large (bi)polaron is investigated for the case where the electron interacts with multiple LO-phonon branches. Explicit expressions for the groundstate energy and the effective mass are obtained within the Feynman polaron model approximation and they are applied to the material SrTiO3. The results of an effective LO-phonon branch approximation are compared with the results in which all LO-phonon branches are explicitly included. We show how the stability region for large bipolaron formation is enlarged when the electrons interact with multiple LO-phonon branches. The possible relevance of this result for the high-Tc superconductors is pointed out.
Analysis of Coupling Using a Transverse Slot in the Common Broad Wall between Two Waveguides

The variational method is used in the present paper to derive the expressions for the complete equivalent circuit of a central transverse slot in the broad wall of a rectangular waveguide. The magnetic field is found from the vector potential involving waveguide (internal) dyadic Green's function. The expression for the self-reaction between the magnetic field and the magnetic current appears in the form of infinite double summation. The double summation appearing in the expression for the self-reaction is simplified to a series, which converges very rapidly. Numerical data evaluated using a complete equivalent circuit is presented.
Semiconductor sources of two-photon states at room temperature in the telecom range

The miniaturization of quantum information technology is a subject attracting a growing attention. The exploitation of spontaneous parametric down conversion in AlGaAs waveguides to generate photon pairs presents several advantages: high nonlinear susceptibility, room-temperature operation and high emission directionality in the telecom range. In this work we will present our recent results on three different kinds of AlGaAs devices: a selectively oxidized source based on form birefringence, a waveguide based on modal phase matching and a microcavity-based source based on counterpropagating phase matching. We will discuss and compare the figures of merit characterizing the three devices for quantum communication applications.
FLAME PROPAGATION WITH MULTIPLE FUELS.

The steady propagation of a flame through a premixed combustible mixture is studied for the case in which the mixture consists of two distinct fuels. The overall chemical reaction mechanism is represented by $A + \nu_A O \to \mu _A P,B + \nu_B O \to \mu _B Q$, where A and B denote the fuels, O is the oxidizer, P and Q are the corresponding products, and $\nu_A ,\mu _A ,\nu_B ,\mu _B $, are stoichiometric coefficients. We employ the method of matched asymptotic expansions to derive a solution for large activation energies, in which case both chemical reactions are confined to a thin layer. The (small) separation distance H between the points where the two reactions go to completion and the propagation velocity U are determined as functions of such quantities as Lewis numbers, activation energies, Damkohler numbers and heat release fractions. The formula for H represents a relative measure of the flame thickness in terms of standard parameters, while that for U determines the role of each reaction in the ov.
Multimode analysis of bubble growth in saturated film boiling

The bubble formation sites in film boiling are the nodes of the instability occurring at the liquid-vapor interface. We perform a linear stability analysis with a time dependent base state, accounting for the growth of the film due to evaporation, in order to identify the most dominant wavelength. Choosing a domain size of five times the wavelength predicted by Berenson [ASME J. Heat Transfer83, 351 (1961)] and an initial liquid-vapor interface profile having a spectrum of wave numbers, we perform numerical simulations to address the effects of decay and growth of the wave numbers on bubble spacing. Numerical simulations have been performed using a coupled level set and volume of fluid algorithm.
Variable stars in the field of open cluster NGC 6819

We report on the discovery of 25 variable stars plus 13 suspected variables found in the field of the open cluster NGC 6819. The stars were identified from time-series photometric data obtained on the Isaac Newton Telescope, La Palma, during two observing runs covering the 19 nights between 1999 June 22-30 and 1999 July 22-31. The variables found include 12 eclipsing binaries with an additional three suspected, nine BY Draconis systems, plus four variables of other types, including one star believed to be a Cepheid. Three of the 15 eclipsing binaries are believed to be cluster members. Details of a further 10 suspected variable stars are also included.
Role of elastic scattering mechanisms in GaInAs∕AlInAs quantum cascade lasers

Electron scattering spectroscopy has been performed on a GaInAs∕AlInAs midinfrared quantum cascade laser by applying a strong magnetic field along its growth axis. The interpretation of the experimental data, supported by our model of the electron lifetime in the presence of a strong magnetic field, very clearly demonstrates that the elastic contribution to the total scattering rate has a weight comparable to that of the optical phonons. The authors believe that this contribution has its origin in the alloy disorder, an efficient mechanism in this material system, which limits the lifetime of the excited subband of the laser transition.
Resonant contributions to the electron-impact ionization of sodiumlike chromium

Electron-impact-ionization cross sections for Na-like Cr 1 3 + have been calculated using semirelativistic distorted-wave Born-exchange approximation. We have included direct ionization, excitation autoionization, and resonant-excitation double-autoionization (REDA) processes in our calculation. The overall agreement between experimental data and our theoretical values is very good. Strong resonant peaks from REDA processes are found, and the REDA processes contribute about 50% and 25% to the average total ionization cross section between 570 and 650 eV and between 650 and 860 eV, respectively. A detailed investigation about the effects of radiative damping and loss channels on the REDA cross section has been carried out. The ionization-rate coefficients of Cr 1 3 + are also presented. Besides, we have compared our calculated results of Fe 1 5 + to experimental data and other theoretical values for examining the reliability of our calculations.
An Interactive Multistage ε-Inequality Constraint Method For Multiple Objectives Decision Making

Multiple objectives decision making (MODM) in engineering design refers to obtaining a preferred optimal solution in the context of conflicting design objectives. Problems with multiple objectives do not have a unique optimal solution but a set of Pareto optimal solutions. This paper presents a new interactive multistage MODM method which captures a decision maker’s preference structure in order to obtain a preferred Pareto solution even for non-convex problems. Representative subsets of an entire Pareto optimal set are generated and expanded based on the decision maker’s preference. The e-constraint method is used to constrain the multiple objectives problem based on the decision maker’s feedback. In addition, ideas from an interactive weighted Tchebycheff approach are applied to reduce the feasible region at each stage, ensuring that the process eventually converges to a preferred solution. The method is demonstrated with two examples: (i) a simple two-bar truss design, and (ii) a more complicated problem in power electronic module design.
Multiparticle Lattice Gas Automata For Reaction Diffusion Systems

Lattice gas automata are a powerful tool to model reaction-diffusion processes. However, the evolution rules limit the number of particles that can be present at each lattice site. This restriction is often a strong limitation to modelling several reaction-diffusion phenomena and, also, lead to very noisy numerical simulations. We propose and study new algorithms which allow for an arbitrary number of particle, while keeping the benefits of the cellular automata approach (close to a microscopic level of description, deal correctly with all degrees of freedom, and is numerically exact).
Thermal Performance of a Closed-Loop Pulsating Heat Pipe With Multiple Heat Sources

A closed-loop pulsating heat pipe with multiple heat sources (CLPHP w/MHS) was invented to be used as a heat transfer medium between a number of heat sources to a single heat sink. However, an issue on the suitable heat source arrangement that causes the heat pipe to have the highest thermal performance was suspicious. The CLPHP w/MHS was made of a copper capillary tube with 32 turns. There were three heat sources with nonidentical input heat flux installed along a longitudinal axis in the evaporator section. Experimental investigations were conducted by permuting the heat sources into six unduplicated arrangements. For the vertical CLPHPs, the highest thermal performance is achieved when heat sources are arranged in consecutive order ascending from the lowest heat flux at the inlet of the evaporator section, since working fluid is promoted to circulate in complete one direction and then the heat can transfer more continuously. Finally, for the horizontal CLPHPs, the highest thermal performance is achieved when the heat sources are arranged in opposite order to the case of vertical CLPHPs, that is, descending from the highest heat flux, since working fluid pulsates with no intermission stop and this causes the heat transfer to be not interrupted.
Dendritic Patterns in Tropical Cumulus: An Observational Analysis

Abstract An observational analysis of the structure and synoptic setting of tropical dendritic cumulus formations was undertaken using 30 months of global data from the Moderate Resolution Imaging Spectroradiometer aboard the National Aeronautics and Space Administration Terra satellite, the Quick Scatterometer aboard the SeaWinds satellite, and the National Centers for Environmental Prediction global reanalysis. This analysis yielded 1216 cases of tropical dendritic cumulus formations of which 61 were randomly selected for quantitative study. From these sample cases, it was found that dendritic patterns in shallow cumulus occurred over warm tropical oceans in response to cold air advection. They typically dissipate downstream in regions of cooler water, neutral to warm advection, or deep convection. Moreover, shallow cumulus formations take on a dendritic pattern only in areas where the background wind velocity is between 1.5 and 13 m s−1 in the surface to the 850-mb layer and a shallow layer of conditio.