Daniel Vrinceanu

Daniel Vrinceanu
Texas Southern University · Department of Physics

PhD

About

139
Publications
13,565
Reads
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2,286
Citations
Additional affiliations
September 2019 - present
Texas Southern University
Position
  • Professor
September 2015 - August 2019
Texas Southern University
Position
  • Professor (Associate)
October 2010 - September 2015
Texas Southern University
Position
  • Professor (Assistant)

Publications

Publications (139)
Preprint
Full-text available
A semi-classical model describing the charge transfer collisions of $C_{60}$ fullerene with different slow ions has been developed to explain available experimental data. This data reveals multiple Breit-Wigner like peaks in the cross sections, with subsequent peaks of reactive cross sections decreasing in magnitude. Calculations of the charge tran...
Chapter
Scientific Machine Learning (SciML) is a new multidisciplinary methodology that combines the data-driven machine learning models and the principle-based computational models to improve the simulations of scientific phenomenon and uncover new scientific rules from existing measurements. This article reveals the experience of using the SciML method t...
Article
Full-text available
Indoor dust can be a major source of heavy metals, nutrients, and bacterial contamination in residential environments and may cause serious health problems. The goal of this research is to characterize chemical and bacterial contaminants of indoor, settled house dust in the Houston Metropolitan region. To achieve this, a total of 31 indoor dust sam...
Preprint
Full-text available
The time-dependent kinetics of formation and evolution of nano-size atomic clusters is investigated and illustrated with the nucleation dynamics of ion-seed Ar$_n$H$^+$ particles. The rates of growth and degradation of Ar-atomic shells around the seed ion are inferred from Molecular Dynamics (MD) simulations. Simulations of cluster formation have b...
Article
Full-text available
Land cover changes impact the soil and water quality which are critical for environmental and human health. The goal of this study is to evaluate whether the land cover change along the Tigris River, one of the largest rivers in the Middle East, is causing any heavy metal contamination. The objectives of this study were: (1) To analyze the metal co...
Article
Full-text available
The nonlinearity of activation functions used in deep learning models is crucial for the success of predictive models. Several simple nonlinear functions, including Rectified Linear Unit (ReLU) and Leaky-ReLU (L-ReLU) are commonly used in neural networks to impose the nonlinearity. In practice, these functions remarkably enhance the model accuracy....
Preprint
Full-text available
Scattering phenomena between charged particles and highly excited Rydberg atoms are of critical importance in many processes in plasma physics and astrophysics. While a Maxwell-Boltzmann (MB) energy distribution for the charged particles is often assumed for calculations of collisional rate coefficients, in this contribution we relax this assumptio...
Preprint
The nonlinearity of activation functions used in deep learning models are crucial for the success of predictive models. There are several commonly used simple nonlinear functions, including Rectified Linear Unit (ReLU) and Leaky-ReLU (L-ReLU). In practice, these functions remarkably enhance the model accuracy. However, there is limited insight into...
Preprint
We employ force-field molecular dynamics simulations to investigate the kinetics of nucleation to new liquid or solid phases in a dense gas of particles, seeded with ions. We use precise atomic pair interactions, with physically correct long-range behavior, between argon atoms and protons. Time-dependence of molecular cluster formation is analyzed...
Article
We employ force-field molecular dynamics simulations to investigate the kinetics of nucleation to new liquid or solid phases in a dense gas of particles, seeded with ions. We use precise atomic pair interactions, with physically correct long-range behaviour, between argon atoms and protons. Time dependence of molecular cluster formation is analysed...
Article
Scattering phenomena between charged particles and highly excited Rydberg atoms are of critical importance in many processes in plasma physics and astrophysics. While a Maxwell–Boltzmann (MB) energy distribution for the charged particles is often assumed for calculations of collisional rate coefficients, in this contribution we relax this assumptio...
Article
We introduce a combined molecular-dynamics and quantum-trajectories code to simulate the effects of near-resonant optical fields on state-vector evolution and particle motion in a collisional system. In contrast to collisionless systems, in which the quantum dynamics of multilevel, laser-driven particles with spontaneous emission can be described w...
Poster
Traditionally, earthquakes and explosions originating in local distances (~ < 200 km) are separated by comparing the amplitude ratio of P to S waves. Explosions, which are considered as point sources, radiate more P wave energy than earthquakes, which are usually double couple sources (Figure 1). Although, this method usually appropriate to discrim...
Preprint
We introduce a combined molecular dynamics (MD) and quantum trajectories (QT) code to simulate the effects of near-resonant optical fields on state-vector evolution and particle motion in a collisional system. In contrast to collisionless systems, in which the quantum dynamics of multi-level, laser-driven particles with spontaneous emission can be...
Preprint
We present analytical expressions for direct evaluation of $\ell$-mixing rate coefficients in proton-excited hydrogen atom collisions and describe a software package for efficient numerical evaluation of the collisional rate coefficients. Comparisons between rate coefficients calculated with various levels of approximation are discussed, highlighti...
Article
Atmospheric haze is a leading candidate for opacity and lack of prominent features in expolanetary spectra, as well as in the atmospheres of Solar system planets, satellites, and comets. Exoplanetary transmission spectra, which carry information about how the planetary atmospheres become opaque to stellar light in transit, often show broad absorpti...
Preprint
Full-text available
Atmospheric haze is the leading candidate for the flattening of expolanetary spectra, as it's also an important source of opacity in the atmospheres of solar system planets, satellites, and comets. Exoplanetary transmission spectra, which carry information about how the planetary atmospheres become opaque to stellar light in transit, show broad fea...
Article
Full-text available
Energy-conserving, angular momentum-changing collisions between protons and highly excited Rydberg hydrogen atoms are important for precise understanding of atomic recombination at the photon decoupling era, and the elemental abundance after primordial nucleosynthesis. Early approaches to $\ell$-changing collisions used perturbation theory for only...
Article
Full-text available
We present a new method to locate the starting points in time of an arbitrary number of (damped) delayed signals. For a finite data sequence, the method permits to first locate the starting point of the component with the longest delay, and then --by iteration-- all the preceding ones. Numerical examples are given and noise sensitivity is tested fo...
Article
Full-text available
In efforts to develop a unique pedagogy for underrepresented high school and undergraduate students, we developed a pilot study to determine the effectiveness of vertically integrating STEM research education from high school students through Ph.D. candidates. The interdisciplinary research project's overarching goal is to assess the impact of envi...
Article
The orthogonal polynomial projection quantization (OPPQ) is an algebraic method for solving Schrödinger's equation by representing the wave function as an expansion in terms of polynomials orthogonal with respect to a suitable reference function R(x), which decays asymptotically not faster than the bound state wave function. The expansion coefficie...
Article
Exactly solvable (ES) systems are those for which the full, discrete spectrum can be solved in closed form. In this work, we argue that a moment's representation analysis can generate these closed-form expressions for the energy in a more direct and transparent manner than the popular Nikiforov-Uvarov (NU) procedure. NU analysis strips the asymptot...
Article
The Yukawa one-component plasma (OCP) model is a paradigm for describing plasmas that contain one component of interest and one or more other components that can be treated as a neutralizing, screening background. In appropriately scaled units, interactions are characterized entirely by a screening parameter, κ. As a result, systems of similar κ sh...
Article
Full-text available
Using first principles calculations, we show the high hydrogen storage capacity of a new class of compounds, metalloboranes. Metalloboranes are transition metal (TM) and borane compounds that obey a novel-bonding scheme. We have found that the transition metal atoms can bind up to 10 H2 molecules.
Article
Full-text available
The Yukawa one-component plasma (OCP) is a paradigm model for describing plasmas that contain one component of interest and one or more other components that can be treated as a neutralizing, screening background. In appropriately scaled units, interactions are characterized entirely by a screening parameter, $\kappa$. As a result, systems of simil...
Article
Full-text available
In 2009-2010, the Laser Interferometer Gravitational-wave Observa- tory (LIGO) operated together with international partners Virgo and GEO600 as a network to search for gravitational waves of astrophysical origin. The sensitiv- ity of these detectors was limited by a combination of noise sources inherent to the instrumental design and its environme...
Article
Full-text available
This paper presents a novel implementation of parallel sparse matrix-matrix multiplication using distributed memory systems on heterogeneous hardware architecture. The proposed algorithm is expected to be linearly scalable up to several thousands of processors for matrices with dimensions over 106 (million). Our approach of parallelism is based on...
Article
A power moments based algebraic method that takes into account the local Taylor’s expansion structure of the wave function is applied to find the spectrum for the two dimensional parity-time symmetric potential V(x, y) = x2 + y2 + igx2y. Converging results are presented for a wide range of the strength parameter g.
Article
We consider the case of highly noisy data coming from two different antennas, with each data set containing a damped signal with the same frequency and decay factor but different amplitude, phase, starting point, and noise. Formally, we treat the first data set as real numbers and the second one as purely imaginary and we add them together. This co...
Article
Full-text available
Many quantum systems admit an explicit analytic Fourier space expansion, besides the usual analytic Schrodinger configuration space representation. We argue that the use of weighted orthonormal polynomial expansions for the physical states (generated through the power moments) can define both an $L^2$ convergent, non-orthogonal, basis expansion wit...
Article
Full-text available
Searches for a stochastic gravitational-wave background (SGWB) using terrestrial detectors typically involve cross-correlating data from pairs of detectors. The sensitivity of such cross-correlation analyses depends, among other things, on the separation between the two detectors: the smaller the separation, the better the sensitivity. Hence, a co-...
Article
Full-text available
We consider the case of highly noisy data coming from two different antennas, each data set containing a damped signal with the same frequency and decay factor but different amplitude, phase, starting point and noise. Formally, we treat the first data set as real numbers and the second one as purely imaginary and we add them together. This complex...
Article
Full-text available
We report on an all-sky search for periodic gravitational waves in the frequency range 50–1000 Hz with the first derivative of frequency in the range −8.9 × 10−10 Hz s−1 to zero in two years of data collected during LIGO's fifth science run. Our results employ a Hough transform technique, introducing a χ2 test and analysis of coincidences between t...
Article
Full-text available
There continues to be great interest in understanding quasi-exactly solvable (QES) systems. In one dimension, QES states assume the form $\Psi(x) =x^\gamma P_d(x) {\cal A}(x)$, where ${\cal A}(x) > 0$ is known in closed form, and $P_d(x)$ is a polynomial to be determined. That is ${{\Psi(x)}\over {x^\gamma{\cal A}(x)}} = \sum_{n=0}^\infty a_nx^n$ t...
Article
Full-text available
During the LIGO and Virgo joint science runs in 2009-2010, gravitational wave (GW) data from three interferometer detectors were analyzed within minutes to select GW candidate events and infer their apparent sky positions. Target coordinates were transmitted to several telescopes for follow-up observations aimed at the detection of an associated op...
Article
Full-text available
Energy-changing electron-hydrogen atom collisions are crucial to regulating the energy balance in astrophysical and laboratory plasmas and relevant to the formation of stellar atmospheres, recombination in H-II clouds, primordial recombination, three-body recombination and heating in ultracold and fusion plasmas. Computational modeling of electron-...
Article
Full-text available
Cosmic string cusps produce powerful bursts of gravitational waves (GWs). These bursts provide the most promising observational signature of cosmic strings. In this letter we report stringent limits on cosmic string models obtained from the analysis of 625 days of observation with the LIGO and Virgo GW detectors. A significant fraction of the cosmi...
Article
Full-text available
Long gamma-ray bursts (GRBs) have been linked to extreme core-collapse supernovae from massive stars. Gravitational waves (GW) offer a probe of the physics behind long GRBs. We investigate models of long-lived (~10-1000s) GW emission associated with the accretion disk of a collapsed star or with its protoneutron star remnant. Using data from LIGO's...
Article
Full-text available
We present the results of a directed search for continuous gravitational waves from unknown, isolated neutron stars in the Galactic Center region, performed on two years of data from LIGO's fifth science run from two LIGO detectors. The search uses a semi-coherent approach, analyzing coherently 630 segments, each spanning 11.5 hours, and then incoh...
Article
Full-text available
We present the results of searches for gravitational waves from a large selection of pulsars using data from the most recent science runs (S6, VSR2 and VSR4) of the initial generation of interferometric gravitational wave detectors LIGO (Laser Interferometric Gravitational-wave Observatory) and Virgo. We do not see evidence for gravitational wave e...
Article
Full-text available
We examine the effectiveness of a new spectral method in solving the two dimensional dipole problem (DP), as originally formulated by Dasbiswas et al (2010 Phys. Rev. B: At. Mol. Opt. Phys. 81 064516), and recently analysed by Amore and Fernandez (AF, 2012 Phys. Rev. B: At. Mol. Opt. Phys. 45 235004), through a large, non-orthogonal basis, Rayleigh...
Article
In this paper, we present a certain number of computer results that require theoretical support in order to acquire a full status.
Article
Accurate energy eigenvalues are obtained by simply projecting the unknown bound state wave function on, essentially, arbitrary sets of orthogonal polynomials, and setting a subset of these to zero. The projection integrals are represented in terms of the power moments of the wave function, obtained recursively by transforming Schrödinger's equation...
Article
In this letter, we invert the ordinary point of view in the analysis of noisy data by treating the signal as a perturbation of the noise. The generating function of pure noise is represented, in the Complex Plane, by poles and zeros (Froissart doublets) having a universal, isotropic statistical distribution. The presence of a signal breaks this rot...
Article
We describe a new method of computing matrix Padé approximants of series with integer data in an efficient and fraction-free way, by controlling the growth of the size of intermediate coefficients. This algorithm is applied to compute high precision Padé approximants of matrix-valued generating functions of time series. As an illustration we show t...
Article
There is an extreme shortage of minority students entering STEM fields in general, and computational science in particular. Therefore, a large segment of the national population has potential for contributions to science and research, but this potential is not being fully realized. Several faculty at Texas Southern University have recruited a numbe...
Article
Full-text available
Collisions between electrically charged particles and neutral atoms are central for understanding the dynamics of neutral gases and plasmas in a variety of physical situaziones of terrestrial and astronomical interest. Specifically, redistribution of angular momentum states within the degenerate shell of highly excited Rydberg atoms occurs efficien...
Article
We consider the Z-transform of a random time series, extension to the complex plane of the dicrete time Fourier transform. Regardless of the specific characteristics of the random signal itself, the singularities of the Z-transform are universally distributed. Addition of a regular signal to the random one locally perturbs this distribution. Deviat...
Article
Control of Rydberg atom wavefunctions has evolved from static or periodic protocols to transport ones, exploiting either modulation or chirping of the controlling periodic field. Applications vary from quantum computing schemes using excitation blockades to the production of anti-hydrogen atoms in Penning traps. Theoretical studies have essentially...
Article
Acoustic waves can be induced by modulating the initial density of ions created from photoionization of cold atoms. A complete modeling of this system requires long Molecular Dynamics Simulations (milliseconds) for a large number of particles (billions). Such extraordinary computational power is still not available. This paper proposes a kinetic mo...
Article
Full-text available
Linear clusters made by tightly connecting two or more metallic nanoparticles have new types of surface plasmon resonances as compared to isolated nanoparticles. These new resonances are related to the size of the junction and to the number of interconnected particles and have direct interpretation as eigenmodes of a Boundary Integral Equation (BIE...
Article
Full-text available
From a time series whose data are embedded in heavy noise, we construct an Hilbert space operator (J-operator) whose discrete spectrum represents the signal while the essential spectrum located on the unit circle, is associated with the noise. Furthermore the essential spectrum, in the absence of signal, is built from roots of unity ("clock" distri...
Article
Full-text available
Cross sections and rate constants for total elastic, diffusion and transfer of metastability for collisions between He(11S)–He(23S) and He(11S)–He(23P) atoms over a wide range of energies and temperatures are presented. The rate constant for spin metastability excitation in He(11S)–He(23P) collision is several orders of magnitude larger than that f...
Article
After creation of the ultracold plasma, the system is far from equilibrium. The electrons equilibrate among themselves and achieve local-thermal equilibrium on a time scale of few nano-seconds. The ions on the other hand expand radially due to the thermal pressure exerted by the electrons, on a much slower time scale (microseconds). Molecular dynam...
Article
Full-text available
The dielectric behavior of a linear cluster of two or more living cells connected by tight junctions is analyzed using a spectral method. The polarizability of this system is obtained as an expansion over the eigenmodes of the linear response operator, showing a clear separation of geometry from electric parameters. The eigenmode with the second la...
Article
Full-text available
Rydberg atom formation is a source of heating in plasmas. The rate of three-body recombination in an ultracold neutral plasma was measured and temperature for the plasma was extracted. With large-scale Monte Carlo and particle-in-cell simulations, we have ab initio calculated the rate of excitation, de-excitation, ionization (and recombination) in...
Article
Full-text available
Rydberg atom formation is a source of heating in plasmas. The rate of three-body recombination in an ultracold neutral plasma was measured and electron temperature was derived from it using standard equilibrium recombination rates. With large-scale Monte Carlo and particle-in-cell simulations, we have calculated ab initio the rate of excitation, de...
Article
We developed a new method in the spectral analysis of noisy time-series. From the Jacobi recursive relation for the denominators of the Pad'e Approximants of the Z-transform of an infinite time-series, we build a J-Operator where each bound state (inside the unit circle) is associated to one damped oscillator while the essential spectrum, which lie...