| Viral Diffusion |
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The enf of 2019 and begining of 2020 were marked by the appearance of the novel
corona virus COVID-19. The spread of this disease to the point of a pandemic
disrupted the lives of the world population. The modelling of the exponential
growth of the rate of infection is a great teachable moment in STEM
disciplines, and have been used to teach the logarithmic scale and how to
fit data and show the seriousness of this infection.
In the present work we present a simple dynamical model of the spread of viral
infections. This model can show a visualization of the spread of the infection
in addition to predicting the number of infections. It uses the diffusion
equation in 2D  , where All of these variables are set at the beginning of the simulation. The algorithm is described below:
Recent Publications in this Project Paulo H. Acioli "Diffusion as a First Model of Spread of Viral Infection", Am. J. Phys. 88, 600 (2020). Python Code for Viral Diffusion |
 Simulation of Viral Infection with ρ=0.012/m2,D=100m2/day,Npop=100,prob=0.2  Logarithmic Scale Graph of the Total Number of Infections  Simulation of Viral Infection with ρ=0.0047/m2,D=100m2/day,Npop=100,prob=0.2  Logarithmic Scale Graph of the Total Number of Infections  Snapshots of a typical simulation cell Susceptible (white), Sick (red), Recovered (white) 
 
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| STEM Education Research |
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Student engagement has been demonstraded an effective strategy for long
term concept retention in physics and STEM education. At NEIU we are
engaging students through the infusion f mini-research projects in the
introductory STEM courses Programing I and II, General Chemistry I and II,
Physical Geology, Calculus II and Computational Statistics, and University
Physics I and II. This implementation is facilitated by Peer Leaders that
help students through the projects by working mostly as a sounding board, but
also as someone that has gone through the process and is able to aid the
students find their own answers to the question raised in their projects.
This work is a result of an NSF-IUSE funded project name Peer Enhanced
Experiential research in STEM (PEERS). An integral portion of the implementation
in the physics courses is the use of computer simulations. We have studied
how computer simulations can help understand classical mechanics as well as
the elusive concept of energy. Our latest contribution was proposing
a diffusion model to simulate the spread of viral infection. Current collaborators Elisabet Head - Earth Science (NEIU) Joseph Hibdon Jr. - Mathematics (NEIU) Ken Nicholson - Chemistry (NEIU) Rachel Trana - Computer Science (NEIU) Sudha Srinivas - Physics (NEIU) Recent Publications in this Project Paulo H. Acioli "Diffusion as a First Model of Spread of Viral Infection", submited to the Am. J. Phys. (2020). Paulo H. Acioli "An example of computer modeling to teach energy conservation concepts", Am. J. Phys. 87, 543 (2019). Paulo H. Acioli, and Sudha Srinivas, "Experiential Learning of Classical Mechanics Through Molecular Dynamics", in Proceedings of the World Conference in Physics Education 2012, Istanbul, Turkey, 2014, pp. 379-390. Acknowledgments This work is supported by a Improving Undergraduate Education in STEM (IUSE) grant #1431839 from the Division of Undergraduate Education (DUE) of the National Science Foundation (NSF). |
 Final result  Energy exchanges  |
| Computational Photoelectron Spectroscopy |
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Experimental photoelectron spectroscopy (PES) is a very powerfull technique to
probe the electronic structure of a molecular system. It has been widely used
in negatively charged clusters of metal elements to probe a transition to
metallicity and half-metallicity in finite systems. PES are obtaining by
shining light (laser) into the molecular system and removing electrons from it.
The difference in the kinetic energy of the electron and the incident laser
energy is the electron binding energy. Although a powerful techinique, PES
cannot provide information about the structure and other properties of the
system. It is then of fundamental importance to perfomr high accuracy
computations to bridge this gap. We have developed a technique to extract electron binding energies from the Kohn-Sham single particle eigenenergies that can be used in any combination of exchange-correlation functionals. This technique has been successfuly applied to: explain the PES and transition to metallicity of magnesium clustersi and the PES and transition to half-metallicity in manganese clusters. More recently we developed a new strategy to explain the role of size, composition, structure and symmetry in mixed-metal clusters. We applied this methodology to disintangle the effects in Al12-, Al13-, and NiAl12-. Current collaborators Julius Jellinek Kit H. Bowen Jr.ek Recent Publications in this Project Paulo H Acioli, "Predicting the Photoelectron Spectrum of Al6Mo-, submitted to Int. J. Quant. Chem. Paulo H. Acioli, Xinxing Zhang, Kit H. Bowen Jr., and Julius Jellinek, "Electron Binding Energy Spectra of AlnMo- Clusters: Measu rements, Calculations, and Theoretical Analysis", J. Phys. Chem. C (2018). P. H. Acioli and J. Jellinek, "Theoretical Analysis of Photoelectron Spectra of Pure and Mixed Metal Clusters: Disentangling Size, Structure and Composition Effects", J. Chem. Phys. C 121, 16665-16672 (2017). Acknowledgments This work was supported by the Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences, U.S. Department of Energy, under Contract DE-AC02-06CH11357. |
 Possible pathways of Al12- into Al13- and NiAl12-  |
| Computation Simulations of Organic Conductors |
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Organic conductors have palyed a remarkable role in the recent years. The
use of polymers have reduced the cost of electronic devices, while being
very versatile. For example the modern solar panels are not only inexpensive
as they are flexible and can be manipulated in many different shapes. It is
then importatn to understand the dynamics of charge transport in organic
materials. In our recent work we have made major contributions in the field. We have established the limit of exciton mobility in highly ordered π-conjugated systems. We studied the thermoelectric effects in organic polymers and we determined the different conduction modes in armchair graphene nanoribbons. Graphene is one of the hottest materials in terms of electronic and magnetic properties and is the driving force in the development of 2D materials. These contributions are of high interest in the green energy technology as they are used either in organic photovotalic devices, transforming light into electricity or vice and versa, or using a temperature gradient to create a an electric current and vice and versa. We are currently interested in study of vacancies in graphene nanoribbons as as the structural and magnetic proerties of Mobius graphene nanorribons. Current collaborators Prof. Demetrio da Silva Filho Universidade de Brasilia - Brazil Prof. Geraldo Magela e Silva Universidade de Brasilia - Brazil Prof. Luiz Fernando Roncaratti Universidade de Brasilia - Brazil Prof. Pedro Henrique de Oliveira Neto Universidade de Brasilia - Brazil Prof. Ricardo Gargano Universidade de Brasilia - Brazil Prof. William Ferreira da Cunha Universidade de Brasilia - Brazil Recent Publications in this Project P. H. Oliveira Neto, D. A. Silva Filho, L. F. Roncaratti, P. H. Acioli, and G. M. e Silva Low-Temperature Seebeck Coefficients for Polaron-Driven Thermoelectric Effect in Organic Polymers, J. Phys. Chem. A 120(27), 4923-4927 (2016)
W. F. Cunha, P. H. Acioli,
P. H. Oliveira Neto, R. Gargano, and G. M. e Silva
Polaron Properties in Armchair Graphene Nanoribbons,
J. Phys. Chem. A
120(27), 4893-4900 (2016)
P. H. Oliveira Neto, Demétrio A. da Silva Filho, W. F. Cunha,
P. H. Acioli,
and G. M. E Silva,
The Limit of Exciton Diffusion in Highly Ordered
π-Conjugated Systems , J. Phys. Chem. C 119,19654 (2015)
Acknowledgments |
 Thermoelectric current (left) and Seebeck coefficient (right) as a function of the temperature. 
Polaron dynamics for 6x200 Armchair Graphene Nanorribon (AGNR) subjected to 1.5 mV/Å electric field. 
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| Interaction of DNA Nucleobases with Noble Metals |
Two possible structures of the Ag-adenine-thymine complex | |
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The underlying mechanisms behind the double helix structure of the DNA are the
formation of hydrogen bonds between complementary base pairs and the relative
orientations of successive base pairs along two polynucleotide strands. These
nucleotides carry the cellular information for replication and synthesis, thus
playing a critical role in metabolism, cellular signaling and enzymatic activity.
Drug therapies, particularly those that seek to enhance or inhibit the cellular
activities facilitated by these nucleotides, work by the binding of site-targeted
drugs to specific nucleotides to achieve this end. For example, atoms of heavy
metals such as platinum and ruthenium play a key role in anti-cancer drugs that
act as intercalating agents and preferentially bind the drug molecule to a
nucleotide in DNA, thereby interfering with the process of normal synthesis and
transcription of DNA. It is now well established that the platinum-based anti-cancer
drug cisplatin (Cl2H6N2Pt), works by the binding of platinum to two 7N guanine
sites, thereby causing intrastrand and interstrand cross-links, the basis of the
drugs efficacy in fighting cancer by inhibiting further uncontrolled growth of the
tumorous cells.
In this project we are interested in investigating, using ab ibitio computations,
alternatives to cisplatin. Systems of interest are small neutral and charged clusters
of silver and gold.
Current collaborators Sudha Srinivas - Faculty Recent Publications in this Project Paulo H. Acioli and Sudha Srinivas, "Silver- and gold-mediated nucleobase bonding", J. Mol. Model. 20(8), 2391 (2014). Acknowledgments We acknowledge the financial support provided by an Extramural Associate Research Development Award (EARDA) Type G11 grant (5G11HD049644-03) from the National Institutes of Health and administered by Northeastern Illinois University, Chicago, IL. |
 Two possible structures of the Ag-guanine-cytosine complex  Stable structures of gas phase a) guanine-Ag-guanine; b) guanine-Au-guanine; and c) guanine-Pt-guanine complexes  |
| Small Clusters and Ligand Interactions |
Lowest Energy Structures of AgN, N=1,4 | |
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Metals and noble metals have an important role in catalytic processes such
as those in the pharmaceutical, automobile and petroleum indistries. Catalysts
have been used in the chemical industry for a long time, however an atomic
level understanding of catalysis is still lacking and therefore catalysts have
traditionally been developed on a trial and error basis. This picture has been
changing recently, thanks to development of faster and more powerfull computers
and quantum chemistry computational methods. These developments are allowing
the computational modeling of metal and metal-ligand interactions and their
role in heterogenous catalysis at reasonable costs. We are currently interested in understanding the nature of bonding of ligands such as oxygen (O2), carbon monoxide (CO) and carbon dioxide (CO2) to small clusters of noble metals and its implications on catalys. We use density functional theory calculations to model the interactions between the clusters and the molecules, the structural and electronic properties of the cluster-molecule system. The long-term goal of this project is to understand how clusters of noble metals like silver interact with small ligand molecules to gain an insight into the catalytic properties of similar metals at a microscopic level. Current collaborators Sudha Srinivas - Faculty Students Involved in the Project Current Cesar Bustos David Capotaq John Gonzales Biguun S. Woods Former Greg Freimark Steve Burkland Indira Bambur Michael Cline Narin Ratanavade Recent Publications in this Project Paulo H. Acioli, Steve Burkland, and Sudha Srinivas, "An exploration of the potential energy surface of the seven atom silver cluster and a carbon monoxide ligand", Eur. Phys. J. D, 66 215 (2012). This articles was featured on the cover of the August 2012 Issue of the European Physics Journal D.  Paulo H. Acioli, N. Ratanavade, M. R. Cline, and Sudha Srinivas, "Density functional Theory study of Ag-Cluster/CO Interactions", in ICCS 2009, Part II, Lecture Notes in Computer Science 5545, G. Allen et al., Eds., Springer-Verlag, Berlin-Heildelberg, 2009, pp. 203-210. Acknowledgments This work was partially supported by a NEIU - COR grant (2007-2008) and a NEIU-SCSE grant (Summer 2009). |
 Lowest Energy Structures of Ag(CO)X, X=1,3  Lowest Energy Structures of Ag2(CO)X, X=1,6  Lowest Energy Structures of Ag3(CO)X, X=1,6  Lowest Energy Structures of Ag4(CO)X, X=1,8 
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| Computational Vibrational Spectroscopy | C2v global minimum of the PES of H5+. | |
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Vibrational spectroscopy can provide insight about the structure and reactivity of
gas phase molecules. In particular, I am interested in studying the
effects of impurities in the excited state spectra of helium clusters and in the
general properties of the ground and excited states of H5+.
In the case of He clusters, these systems have being studied in the past, but most
of the studies were restricted to the ground state. I am interested in studying
their excited states. The main goal is to understand the difference between the
spectra of the pure He clusters and the spectra as an impurity is added. This
study will focus in the energies of the excited states and in their pair density
functions. The understanding of these differences at the molecular level is of
great importance to shed light in such a fascinating systems, which display exotic
properties such as superfluidity in bulk quantities. The main challenge to carry
out such study is to solve the multidimensional integrals that appear in the
eigenvalue problems defined by the time-independent Shrödinger equation. One
can overcome such challenge with the use of correlation function quantum Monte
Carlo (CFQMC), a technique that we have shown to be effective in treating the
vibrational spectrum, beyond the harmonic approximation, of systems with more
than four atoms. Quantum Monte Carlo techniques can be also utilized to study
H5+. This molecule is of particular interest in the
physics and chemistry of interstellar medium. It is a weakly bound complex
important in reactions involving H3+ and H2. One
of the questions is to decide if the complex, in its ground state is symmetric
or if it resembles H2 bound to H3+. Another
important aspect is to study the isotope effects when H atoms are replaced by deuterium.
Current collaborators Prof. Joel M. Bowman Emory University Prof. Geraldo Magela e Silva Universidade de Brasilia - Brazil Prof. Ricardo Gargano Universidade de Brasilia - Brazil Dr. Angelo Marconi Maniero Universidade Federal da Bahia - Brazil Recent Publications in this Project Angelo M. Maniero, Paulo H. Acioli, Geraldo Magela e Silva, Ricardo Gargano, "Theoretical calculations of a new potential energy surface for the H + Li2 reaction", Chem. Phys. Lett. 490(4-6), 123 (2010). G. M. e Silva, R. Gargano, W. B. da Silva, L. F. Roncaratti, and Paulo H. Acioli, "Quantum Monte Carlo and Genetic Algorithm Study of the Potential Energy Surface of the H5+ Molecule", Int. J. Quant. Chem. 108 (13), 2318 (2008). Paulo H. Acioli, Z. Xie, B. J. Braams, and J. M. Bowman, "Vibrational Ground State properties of H5+ and its Isotopomers from Diffusion Monte Carlo Calculations", J. Chem. Phys. 128, 104318 (2008). A. M. Maniero and P. H. Acioli , "Potential energy curves of Li2 and LiH from a full configuration interaction pseudopotential procedure". Int. J. Quant. Chem. 103 , 711 (2005). Acknowledgments This work was partially supported by the National Science Foundation through Research Opportunity Award as Supplemental Funding to CHE-0446527 (JM Bowman - PI). |
 D2d saddle point of the PES of H5+.  HH pair distribution function of the H5+. The vertical sticks represent the bond lengths at the C2v global minimum (solid) and at the lowest D2d (dashed) saddle point of the PES.  Energy landscape of the reactants, intermediate complexes, and products for scattering reactions of H3+ and H2 and isotopomers.  |
| Wind Power Generation | A Wind Turbine Made of Recycled Materials | |
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The ever growing development of new technologies demands a continuous growth in
energy production. Traditional energy production relies heavily on fossil fuels.
At the current production rate the known deposits of coal, oil, and natural
gas are expected to last for 148, 43, and 61 years, respectively. In addition,
fossil fuels have a harmful impact in our environment. For instance, it is
estimated that 90% of the greenhouse effect emissions in the US come from the
burning of fossil fuels. Hidroelectric power plants are cleaner but they have
a huge impact in the environment. The impact can be physical or biological.
These effects start during the construction of the dam and they can change river
itself as well as the surrounding ecosystem. The blocking of the flow of water
have also a huge impact as the land that gets flooded could be home of many
endangered species, could have been used for residence or even agriculture.
Nuclear power plants are somewhat clean during the production stage. However,
there is a big risk of nuclear accidents such as the Chernobyl disaster in 1987
and the Fukushima I nuclear accident in 2011. To address the ever growing energy
demand and to reduce the negative environmental impacts there is a push for cleaner
and renewable sources of energy. Ethanol is a cleaner alternative to oil. However,
large scale alcohol production for energy production does create other issues such
as the use of land for non food producing agriculture. Solar and wind producing
generators are a greener alternative. Although wind and solar farming also have
negative environmental impact and the cost and efficiency are still far from ideal
many governments are still promoting the construction of vast wind "farms,"
and encouraging private companies with subsidies and regulatory support. The goals
of this project are: 1) to study the viability of the use of wind and solar generators
around NEIU neighborhood; 2) To research the basic physics of electric power generation
in general, and wind power generation in particular; 3) Design and build a wind power
generator that would be adequate for low power applications in a urban environment;
4) Write a wind generation booklet to be distribute in local mid and high schools to
aid students that are interested in developing renewable energy science projects.
Students Involved in the Project Sergio Guerrero Max Hansen Thomas McLaughlin Esosa Ogbomo Steve Roothaan Caroline Williams Recent Presentations in this Project Esosa Ogbomo, Thomas McLaughlin, Max Hansen, and Paulo Acioli, "Building a Wind Turbine from Recycled Components", Poster presented at the Annual SACNAS meeting, Seattle, Oct. 2012. Steven Roothaan, Caroline Williams, Sergio Guerrero, and Paulo Acioli, "Optimization of H-Darrieus Vertical Axis Wind Turbine Design for Application in Urban Areas", Poster presented at the Annual SACNAS meeting, Seattle, Oct. 2012. Acknowledgments This work supported by a USDA-CREEAR grant. |
 Response of a Vertical Axis Wind Turbine in Turbulent Air  |
| Last Updated: 4/01/2009 . |
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