IOSR Journal of Applied Physics (IOSR-JAP) is an open access international journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Modern electronic structure codes give relatively consistent equations of state. There remain challenges to fully automating electronic structure calculations, such as developing robust materials analysis software to integrate calculations, detecting and correcting errors, and managing scientific workflows. Frameworks like pymatgen, ASE, the Materials Project, AiiDA and Custodian provide modular, reusable tools for high-throughput electronic structure computations and extensive materials analysis capabilities. FireWorks serves as a workflow manager to automate calculations over diverse supercomputing resources. With automation comes large quantities of materials data that can be leveraged for materials design and discovery.
NANO281 is the University of California San Diego NanoEngineering Department's first course on the application of data science in materials science. It is taught by Professor Shyue Ping Ong of the Materials Virtual Lab (http://www.materialsvirtuallab.org).
I gave 1 hour seminar at ANSTO (Australian Nuclear Science and Technology Organization) to introduce my approach to magnetism. I see myself as an experimental physicist who is studying magnetism by using neutron scattering techniques. Throughout my career, I had learned local structure analysis (PDF), magnetic structural analysis, and inelastic neutron scattering technique to investigate superconductor, multiferroics, antiferromagnets, helimagnets, and frustrated magnets. I was trying to explain my approach to magnetism as an experiment physicist to both professional scientists and novices.
1) The document discusses studies of photon detection efficiency and position resolution of the electromagnetic calorimeter (EMC) at the BESIII experiment using control samples of initial state radiation processes.
2) Datasets of J/psi and psi(3770) decays are used to calibrate the EMC energy and position measurements, which are affected by factors like crystal quality and electronic noise.
3) The photon detection efficiency is found to agree between data and Monte Carlo simulation to within 1%, and the EMC position resolution is improved by applying new correction factors derived from calibration samples.
This document summarizes work using molecular dynamics simulations to calculate the viscosity of liquid nickel. The researchers used a modified embedded atom method potential to simulate liquid nickel across a range of temperatures. Preliminary results for the viscosity fell within the range of available experimental data. Future work involves further testing and developing optimized potentials for nickel alloys and calculating other physically relevant parameters for larger scale simulations.
This document discusses various methods for detecting neutrinos. It is very difficult to detect neutrinos due to their weak interactions. The earliest detection was through inverse beta decay using a nuclear reactor. Later, the Sudbury Neutrino Observatory was able to detect neutrinos via different interactions in deuterium, providing evidence of neutrino flavor oscillations. Now, large detectors like IceCube are detecting high-energy neutrinos from astrophysical sources. Measuring the neutrino mass precisely remains challenging but various techniques using beta decay spectra provide upper limits.
Apartes de la Conferencia de la SJG del 14 y 21 de Enero de 2012: Hubble diag...SOCIEDAD JULIO GARAVITO
This document discusses using gamma-ray bursts (GRBs) to test cosmological predictions of the Gurzadyan-Xue (GX) model of dark energy. It calibrates GRBs as standard candles using empirical relations between their observed characteristics. It then uses 3 samples of GRB data spanning redshifts up to 7 to generate Hubble diagrams and compare them to the predictions of GX models and the standard ΛCDM model. The analysis shows GX models are compatible with one GRB sample but more data is needed to clarify the issues of GRBs as standard candles and the physics underlying the empirical relations.
Modern electronic structure codes give relatively consistent equations of state. There remain challenges to fully automating electronic structure calculations, such as developing robust materials analysis software to integrate calculations, detecting and correcting errors, and managing scientific workflows. Frameworks like pymatgen, ASE, the Materials Project, AiiDA and Custodian provide modular, reusable tools for high-throughput electronic structure computations and extensive materials analysis capabilities. FireWorks serves as a workflow manager to automate calculations over diverse supercomputing resources. With automation comes large quantities of materials data that can be leveraged for materials design and discovery.
NANO281 is the University of California San Diego NanoEngineering Department's first course on the application of data science in materials science. It is taught by Professor Shyue Ping Ong of the Materials Virtual Lab (http://www.materialsvirtuallab.org).
I gave 1 hour seminar at ANSTO (Australian Nuclear Science and Technology Organization) to introduce my approach to magnetism. I see myself as an experimental physicist who is studying magnetism by using neutron scattering techniques. Throughout my career, I had learned local structure analysis (PDF), magnetic structural analysis, and inelastic neutron scattering technique to investigate superconductor, multiferroics, antiferromagnets, helimagnets, and frustrated magnets. I was trying to explain my approach to magnetism as an experiment physicist to both professional scientists and novices.
1) The document discusses studies of photon detection efficiency and position resolution of the electromagnetic calorimeter (EMC) at the BESIII experiment using control samples of initial state radiation processes.
2) Datasets of J/psi and psi(3770) decays are used to calibrate the EMC energy and position measurements, which are affected by factors like crystal quality and electronic noise.
3) The photon detection efficiency is found to agree between data and Monte Carlo simulation to within 1%, and the EMC position resolution is improved by applying new correction factors derived from calibration samples.
This document summarizes work using molecular dynamics simulations to calculate the viscosity of liquid nickel. The researchers used a modified embedded atom method potential to simulate liquid nickel across a range of temperatures. Preliminary results for the viscosity fell within the range of available experimental data. Future work involves further testing and developing optimized potentials for nickel alloys and calculating other physically relevant parameters for larger scale simulations.
This document discusses various methods for detecting neutrinos. It is very difficult to detect neutrinos due to their weak interactions. The earliest detection was through inverse beta decay using a nuclear reactor. Later, the Sudbury Neutrino Observatory was able to detect neutrinos via different interactions in deuterium, providing evidence of neutrino flavor oscillations. Now, large detectors like IceCube are detecting high-energy neutrinos from astrophysical sources. Measuring the neutrino mass precisely remains challenging but various techniques using beta decay spectra provide upper limits.
Apartes de la Conferencia de la SJG del 14 y 21 de Enero de 2012: Hubble diag...SOCIEDAD JULIO GARAVITO
This document discusses using gamma-ray bursts (GRBs) to test cosmological predictions of the Gurzadyan-Xue (GX) model of dark energy. It calibrates GRBs as standard candles using empirical relations between their observed characteristics. It then uses 3 samples of GRB data spanning redshifts up to 7 to generate Hubble diagrams and compare them to the predictions of GX models and the standard ΛCDM model. The analysis shows GX models are compatible with one GRB sample but more data is needed to clarify the issues of GRBs as standard candles and the physics underlying the empirical relations.
Prof Ong gave a webinar talk on the AI Revolution in Materials Science for the Singapore Agency of Science Technology and Research (A*STAR). In this talk, he discussed the big challenges in materials science where AI can potentially make a huge impact towards addressing as well as outstanding challenges and opportunities to bringing forth the AI revolution to the materials domain.
Nucleation III: Phase-field crystal modeling of nucleation processDaniel Wheeler
This document summarizes research on modeling nucleation processes using phase-field crystal modeling. It begins with an introduction to complex polycrystalline structures that form through nucleation and growth processes. It then provides an overview of the phase-field crystal approach and how it can be used to model nucleation and growth dynamics. Specific applications discussed include modeling homogeneous and heterogeneous nucleation barriers using the Euler-Lagrange method and simulating non-equilibrium nucleation processes using the diffusive phase-field crystal model. The document highlights how phase-field crystal modeling can provide insights into precursor structures, growth morphologies, and freezing mechanisms observed in experiments.
Phase-field modeling of crystal nucleation II: Comparison with simulations an...Daniel Wheeler
This document summarizes phase-field modeling of crystal nucleation. It discusses:
1) Homogeneous nucleation models using the phase-field method and their comparison to molecular dynamics simulations and experiments for systems like nickel and Lennard-Jones argon.
2) Applications of the phase-field model to heterogeneous systems like ice-water nucleation.
3) The effects of different double-well and interpolation functions on nucleation behavior in phase-field models.
Nucleation III: Phase-field crystal modeling of nucleation processPFHub PFHub
The document summarizes research on modeling nucleation processes using phase-field crystal modeling. It discusses how phase-field crystal models can capture nucleation and growth phenomena observed in experiments and atomistic simulations. Specifically, it describes how different phase-field crystal models are able to simulate:
1) Homogeneous and heterogeneous nucleation processes in 2D and 3D, including the effects of lattice mismatch and particle-induced nucleation.
2) Continuous cooling simulations that show amorphous phase formation prior to crystallization, similar to experimental observations in colloids.
3) Instantaneous quenching simulations that produce amorphous clusters and domains that facilitate heterogeneous nucleation of body-centered cubic crystals.
4
Investigation of Steady-State Carrier Distribution in CNT Porins in Neuronal ...Kyle Poe
In this work, the carrier distribution of a carbon nanotube inserted into the spinal ganglion neuronal membrane is examined. After primary characterization based on previous work, the nanotube is approximated as a one-dimensional system, and the Poisson and Schrödinger equations are solved using an iterative finite-difference scheme. It was found that carriers aggregate near the center of the tube, with a negative carrier density of ⟨ρn⟩ = 7.89 × 10^13 cm−3 and positive carrier density of ⟨ρp⟩ = 3.85 × 10^13 cm−3. In future work, the erratic behavior of convergence will be investigated.
Phase-field modeling of crystal nucleation: Comparison with simulations and e...PFHub PFHub
The document summarizes a talk on phase-field modeling of crystal nucleation. It compares simulations using single-field phase-field models to molecular dynamics simulations and experiments for various materials. For nickel, water, and a Lennard-Jones system, the "standard" phase-field model agrees well with the simulations and experiments. However, for a hard-sphere system, a different phase-field model based on Ginzburg-Landau theory is needed. Further theoretical work is required to develop phase-field models that can accurately describe crystal nucleation across different materials.
Theoretical and Applied Phase-Field: Glimpses of the activities in IndiaDaniel Wheeler
1. The document summarizes recent work on phase-field modeling from several research groups in India.
2. It describes applications of phase-field modeling to spinodal decomposition, grain growth, precipitate evolution, and multi-phase solidification.
3. It highlights a recent study by the author using phase-field modeling to predict the equilibrium shapes of coherent precipitates under the influence of elastic stresses. The model accounts for elastic anisotropy and different eigenstrain configurations.
Phase-field modeling of crystal nucleation I: Fundamentals and methodsDaniel Wheeler
This document summarizes phase-field modeling of homogeneous crystal nucleation using two main methods. The first method adds fluctuations (noise) to the phase-field equations of motion to mimic natural nucleation. The noise amplitude is determined by the fluctuation-dissipation theorem. This models nucleation without assuming a sharp interface or bulk properties. The second method places supercritical crystal seeds randomly in space and time to model nucleation. Quantitative results from both methods are difficult to obtain due to limitations of classical nucleation theory. The document outlines the phase-field model and equations used to simulate homogeneous nucleation and crystal growth in 2D with and without noise to demonstrate convergence with spatial and temporal discretization.
This document discusses density functional theory (DFT) and exact exchange methods. It provides background on DFT, the Kohn-Sham equations, and common exchange-correlation functionals like the local density approximation (LDA) and generalized gradient approximations (GGA). It then introduces exact exchange (EXX) methods, which neglect correlation and use the Hartree-Fock exchange energy. Calculating the functional derivative of the exchange energy is discussed to obtain the exchange potential within the Kohn-Sham scheme for EXX.
Apartes de la Conferencia de la SJG del 14 y 21 de Enero de 2012Nonlinear ele...SOCIEDAD JULIO GARAVITO
This document summarizes a research article about nonlinear electrodynamics and its effects on the polarization of the cosmic microwave background radiation. It introduces nonlinear electrodynamics models as alternatives to Maxwell's electrodynamics. The document then discusses how nonlinear electrodynamics is minimally coupled to gravity and derives the relevant equations of motion. It focuses on analyzing the Pagels-Tomboulis nonlinear electrodynamics Lagrangian and computing the polarization angle of photons propagating in an expanding universe with planar symmetry. Constraints on the nonlinear electrodynamics parameter are obtained using data on cosmic magnetic field strengths and the rotation of CMB polarization spectra measured by experiments.
This study measured the X-ray fluorescence spectra of chromium compounds with different oxidation states (Cr0, Cr3+, Cr6+) using a high-resolution crystal spectrometer. Second-order contributions like plasmon satellites were resolved below the main Kβ1,3 emission line. The intensities and energies of these satellites varied between the compounds. Specifically, the Kβ' satellite had higher intensity and was at a lower energy for Cr3+ compared to Cr6+ or Cr0. Similar trends were observed for other satellites like Kβ5. The results provide information about how chemical bonding affects X-ray emission spectra.
This document proposes that dark energy may be an artifact of the free energy required to encode classical information about quantum systems into the environment. It applies the framework of quantum Darwinism to model how the positions of stars are encoded in the ambient photon field. Assuming Landauer's principle, encoding the positions of 10^25 stars with 10 km resolution requires a free energy equivalent to the observed dark energy density. Finer encodings would require much higher energies inconsistent with observations. Thus dark energy may represent the cost of encoding classical information rather than a property of empty space.
Phonon frequency spectrum through lattice dynamics and normal coordinate anal...Alexander Decker
The document discusses the lattice dynamics and normal coordinate analysis of the high-temperature superconductor Tl2Ca3Ba2Cu4O12. It presents the following key points:
1. Lattice dynamics calculations using the three-body force shell model reproduce observed Raman and infrared phonon frequencies reasonably well.
2. Normal coordinate analysis using Wilson's F-G matrix method yields vibrational frequencies in good agreement with experimental values and lattice dynamics calculations.
3. Potential energy distribution calculations confirm that the chosen vibrational frequencies make the maximum contribution to the potential energy of the material's normal coordinate frequencies.
Density functional theory (DFT) and the concepts of the augmented-plane-wave ...ABDERRAHMANE REGGAD
Density functional theory (DFT) is a quantum mechanical method used to investigate the electronic structure of materials. The document discusses DFT and the linearized augmented plane wave plus local orbital (LAPW+lo) method implemented in the Wien2k software. Wien2k is widely used to study the properties of solids and surfaces using an all-electron, relativistic, and full-potential DFT approach. The document provides an overview of the theoretical foundations of DFT and LAPW methods as well as examples of applications studied with Wien2k.
Ab-initio real-time spectroscopy: application to non-linear opticsClaudio Attaccalite
This document discusses ab-initio real-time spectroscopy and its application to non-linear optics. It begins with an overview of non-linear optics and the polarization response. It then discusses using time-dependent density functional theory to calculate nonlinear optical properties in real-time by solving the time-dependent Schrodinger equation under an external electric field. Examples are given of calculating second and third harmonic generation in materials. The document also discusses approaches to address challenges like treating bulk polarization and including many-body effects.
Nonlinear response of solids with Green's functions and TD-D(P)FTClaudio Attaccalite
This document summarizes nonlinear response theory using real-time propagation of the wavefunction. The wavefunction approach allows calculating nonlinear response to all orders using the same equations of motion. Local fields and excitonic effects are important beyond linear response. Time-dependent density functional theory may provide an alternative, but functionals must depend on both density and polarization to describe nonlinear optics in solids. Developing such functional is an important open problem. Applications include second and third harmonic generation in semiconductors and two-dimensional materials.
Are you interested in increasing your Google PageRank?believe52
Google PageRank is an algorithm that determines where a website ranks in Google search results. It is based on the number and quality of inbound links to a site, with more popular sites that link to a page resulting in a higher PageRank. Improving a site's PageRank is important because it leads to more traffic and visibility in Google searches. Website owners can boost their PageRank through link campaigns that aim to get links from relevant, popular sites.
A Review of FPGA-based design methodologies for efficient hardware Area estim...IOSR Journals
This document reviews different FPGA-based design methodologies and optimization techniques that can be used for efficient hardware area estimation. It discusses the standard FPGA design flow including capturing the design, logic synthesis, technology mapping, placement, routing and bitstream generation. It then reviews several area estimation techniques such as resource sharing, proper reset strategies, optimizing for speed, and targeting specific FPGA technologies. Several papers are cited that propose techniques for fast area estimation, hardware/software partitioning for FPGAs, estimating multipliers and DSP blocks, and estimating designs captured using different languages. The document concludes that factors like FPGA architecture selection, design methodology, and optimization techniques play an important role in efficient FPGA-based design.
Prof Ong gave a webinar talk on the AI Revolution in Materials Science for the Singapore Agency of Science Technology and Research (A*STAR). In this talk, he discussed the big challenges in materials science where AI can potentially make a huge impact towards addressing as well as outstanding challenges and opportunities to bringing forth the AI revolution to the materials domain.
Nucleation III: Phase-field crystal modeling of nucleation processDaniel Wheeler
This document summarizes research on modeling nucleation processes using phase-field crystal modeling. It begins with an introduction to complex polycrystalline structures that form through nucleation and growth processes. It then provides an overview of the phase-field crystal approach and how it can be used to model nucleation and growth dynamics. Specific applications discussed include modeling homogeneous and heterogeneous nucleation barriers using the Euler-Lagrange method and simulating non-equilibrium nucleation processes using the diffusive phase-field crystal model. The document highlights how phase-field crystal modeling can provide insights into precursor structures, growth morphologies, and freezing mechanisms observed in experiments.
Phase-field modeling of crystal nucleation II: Comparison with simulations an...Daniel Wheeler
This document summarizes phase-field modeling of crystal nucleation. It discusses:
1) Homogeneous nucleation models using the phase-field method and their comparison to molecular dynamics simulations and experiments for systems like nickel and Lennard-Jones argon.
2) Applications of the phase-field model to heterogeneous systems like ice-water nucleation.
3) The effects of different double-well and interpolation functions on nucleation behavior in phase-field models.
Nucleation III: Phase-field crystal modeling of nucleation processPFHub PFHub
The document summarizes research on modeling nucleation processes using phase-field crystal modeling. It discusses how phase-field crystal models can capture nucleation and growth phenomena observed in experiments and atomistic simulations. Specifically, it describes how different phase-field crystal models are able to simulate:
1) Homogeneous and heterogeneous nucleation processes in 2D and 3D, including the effects of lattice mismatch and particle-induced nucleation.
2) Continuous cooling simulations that show amorphous phase formation prior to crystallization, similar to experimental observations in colloids.
3) Instantaneous quenching simulations that produce amorphous clusters and domains that facilitate heterogeneous nucleation of body-centered cubic crystals.
4
Investigation of Steady-State Carrier Distribution in CNT Porins in Neuronal ...Kyle Poe
In this work, the carrier distribution of a carbon nanotube inserted into the spinal ganglion neuronal membrane is examined. After primary characterization based on previous work, the nanotube is approximated as a one-dimensional system, and the Poisson and Schrödinger equations are solved using an iterative finite-difference scheme. It was found that carriers aggregate near the center of the tube, with a negative carrier density of ⟨ρn⟩ = 7.89 × 10^13 cm−3 and positive carrier density of ⟨ρp⟩ = 3.85 × 10^13 cm−3. In future work, the erratic behavior of convergence will be investigated.
Phase-field modeling of crystal nucleation: Comparison with simulations and e...PFHub PFHub
The document summarizes a talk on phase-field modeling of crystal nucleation. It compares simulations using single-field phase-field models to molecular dynamics simulations and experiments for various materials. For nickel, water, and a Lennard-Jones system, the "standard" phase-field model agrees well with the simulations and experiments. However, for a hard-sphere system, a different phase-field model based on Ginzburg-Landau theory is needed. Further theoretical work is required to develop phase-field models that can accurately describe crystal nucleation across different materials.
Theoretical and Applied Phase-Field: Glimpses of the activities in IndiaDaniel Wheeler
1. The document summarizes recent work on phase-field modeling from several research groups in India.
2. It describes applications of phase-field modeling to spinodal decomposition, grain growth, precipitate evolution, and multi-phase solidification.
3. It highlights a recent study by the author using phase-field modeling to predict the equilibrium shapes of coherent precipitates under the influence of elastic stresses. The model accounts for elastic anisotropy and different eigenstrain configurations.
Phase-field modeling of crystal nucleation I: Fundamentals and methodsDaniel Wheeler
This document summarizes phase-field modeling of homogeneous crystal nucleation using two main methods. The first method adds fluctuations (noise) to the phase-field equations of motion to mimic natural nucleation. The noise amplitude is determined by the fluctuation-dissipation theorem. This models nucleation without assuming a sharp interface or bulk properties. The second method places supercritical crystal seeds randomly in space and time to model nucleation. Quantitative results from both methods are difficult to obtain due to limitations of classical nucleation theory. The document outlines the phase-field model and equations used to simulate homogeneous nucleation and crystal growth in 2D with and without noise to demonstrate convergence with spatial and temporal discretization.
This document discusses density functional theory (DFT) and exact exchange methods. It provides background on DFT, the Kohn-Sham equations, and common exchange-correlation functionals like the local density approximation (LDA) and generalized gradient approximations (GGA). It then introduces exact exchange (EXX) methods, which neglect correlation and use the Hartree-Fock exchange energy. Calculating the functional derivative of the exchange energy is discussed to obtain the exchange potential within the Kohn-Sham scheme for EXX.
Apartes de la Conferencia de la SJG del 14 y 21 de Enero de 2012Nonlinear ele...SOCIEDAD JULIO GARAVITO
This document summarizes a research article about nonlinear electrodynamics and its effects on the polarization of the cosmic microwave background radiation. It introduces nonlinear electrodynamics models as alternatives to Maxwell's electrodynamics. The document then discusses how nonlinear electrodynamics is minimally coupled to gravity and derives the relevant equations of motion. It focuses on analyzing the Pagels-Tomboulis nonlinear electrodynamics Lagrangian and computing the polarization angle of photons propagating in an expanding universe with planar symmetry. Constraints on the nonlinear electrodynamics parameter are obtained using data on cosmic magnetic field strengths and the rotation of CMB polarization spectra measured by experiments.
This study measured the X-ray fluorescence spectra of chromium compounds with different oxidation states (Cr0, Cr3+, Cr6+) using a high-resolution crystal spectrometer. Second-order contributions like plasmon satellites were resolved below the main Kβ1,3 emission line. The intensities and energies of these satellites varied between the compounds. Specifically, the Kβ' satellite had higher intensity and was at a lower energy for Cr3+ compared to Cr6+ or Cr0. Similar trends were observed for other satellites like Kβ5. The results provide information about how chemical bonding affects X-ray emission spectra.
This document proposes that dark energy may be an artifact of the free energy required to encode classical information about quantum systems into the environment. It applies the framework of quantum Darwinism to model how the positions of stars are encoded in the ambient photon field. Assuming Landauer's principle, encoding the positions of 10^25 stars with 10 km resolution requires a free energy equivalent to the observed dark energy density. Finer encodings would require much higher energies inconsistent with observations. Thus dark energy may represent the cost of encoding classical information rather than a property of empty space.
Phonon frequency spectrum through lattice dynamics and normal coordinate anal...Alexander Decker
The document discusses the lattice dynamics and normal coordinate analysis of the high-temperature superconductor Tl2Ca3Ba2Cu4O12. It presents the following key points:
1. Lattice dynamics calculations using the three-body force shell model reproduce observed Raman and infrared phonon frequencies reasonably well.
2. Normal coordinate analysis using Wilson's F-G matrix method yields vibrational frequencies in good agreement with experimental values and lattice dynamics calculations.
3. Potential energy distribution calculations confirm that the chosen vibrational frequencies make the maximum contribution to the potential energy of the material's normal coordinate frequencies.
Density functional theory (DFT) and the concepts of the augmented-plane-wave ...ABDERRAHMANE REGGAD
Density functional theory (DFT) is a quantum mechanical method used to investigate the electronic structure of materials. The document discusses DFT and the linearized augmented plane wave plus local orbital (LAPW+lo) method implemented in the Wien2k software. Wien2k is widely used to study the properties of solids and surfaces using an all-electron, relativistic, and full-potential DFT approach. The document provides an overview of the theoretical foundations of DFT and LAPW methods as well as examples of applications studied with Wien2k.
Ab-initio real-time spectroscopy: application to non-linear opticsClaudio Attaccalite
This document discusses ab-initio real-time spectroscopy and its application to non-linear optics. It begins with an overview of non-linear optics and the polarization response. It then discusses using time-dependent density functional theory to calculate nonlinear optical properties in real-time by solving the time-dependent Schrodinger equation under an external electric field. Examples are given of calculating second and third harmonic generation in materials. The document also discusses approaches to address challenges like treating bulk polarization and including many-body effects.
Nonlinear response of solids with Green's functions and TD-D(P)FTClaudio Attaccalite
This document summarizes nonlinear response theory using real-time propagation of the wavefunction. The wavefunction approach allows calculating nonlinear response to all orders using the same equations of motion. Local fields and excitonic effects are important beyond linear response. Time-dependent density functional theory may provide an alternative, but functionals must depend on both density and polarization to describe nonlinear optics in solids. Developing such functional is an important open problem. Applications include second and third harmonic generation in semiconductors and two-dimensional materials.
Are you interested in increasing your Google PageRank?believe52
Google PageRank is an algorithm that determines where a website ranks in Google search results. It is based on the number and quality of inbound links to a site, with more popular sites that link to a page resulting in a higher PageRank. Improving a site's PageRank is important because it leads to more traffic and visibility in Google searches. Website owners can boost their PageRank through link campaigns that aim to get links from relevant, popular sites.
A Review of FPGA-based design methodologies for efficient hardware Area estim...IOSR Journals
This document reviews different FPGA-based design methodologies and optimization techniques that can be used for efficient hardware area estimation. It discusses the standard FPGA design flow including capturing the design, logic synthesis, technology mapping, placement, routing and bitstream generation. It then reviews several area estimation techniques such as resource sharing, proper reset strategies, optimizing for speed, and targeting specific FPGA technologies. Several papers are cited that propose techniques for fast area estimation, hardware/software partitioning for FPGAs, estimating multipliers and DSP blocks, and estimating designs captured using different languages. The document concludes that factors like FPGA architecture selection, design methodology, and optimization techniques play an important role in efficient FPGA-based design.
Hybrid Algorithm for Clustering Mixed Data SetsIOSR Journals
This document summarizes a hybrid algorithm for clustering mixed data sets that was proposed in reference [1]. The algorithm uses a genetic k-means approach to cluster both numeric and categorical data, overcoming limitations of other algorithms that can only handle one data type. It aims to minimize the total within-cluster variation to group similar objects. The selection operator uses proportional selection to determine the population for the next generation based on each solution's probability and fitness. The algorithm was reviewed, implemented in a prototype application, and found to improve performance compared to other related clustering algorithms like GKMODE and IGKA that also handle mixed data types.
Why U.S. Bank Lost Its Case against Ibanez on a Foreclosed Property David Zak Lawyer
A Massachusetts lawyer noted among Hispanic homeowners, David Zak possesses a strong background in mortgage lending laws. Having previously worked with the underwriting and loan origination departments for many financial institutions, David Zak is knowledgeable about real estate title transfers.
This document summarizes the design and study of a compact and wideband microstrip U-slot patch antenna for Wi-Max applications. The antenna was designed to operate in the 5.25GHz Wi-Max band with very low return loss. Design formulas are provided to calculate the dimensions of the rectangular microstrip patch antenna. Simulation results show the return loss is below -30dB from 5.15GHz to 5.85GHz, meeting the bandwidth requirements. The proposed antenna design achieves wideband operation using a 3-layer substrate with total thickness of 1.6mm.
This document summarizes a new fault injection approach for testing network-on-chip (NoC) architectures. The approach uses a dual-processor system on an FPGA to inject faults into a NoC design under test and evaluate the effects. Faults are injected by modifying the FPGA configuration memory to physically implement different fault models. The approach allows testing of routing and logic resources without intrusive test modules. Experimental results demonstrate the effectiveness of classifying faults in a mesh NoC case study implemented on the FPGA.
The document discusses different types of energy:
- Energy exists in different forms and can change between forms but the total amount of energy remains constant.
- The types of energy discussed include kinetic, light, heat, chemical, electrical, nuclear, and gravitational energy.
- Each type of energy is explained briefly, for example light energy is electromagnetic radiation and kinetic energy can convert to potential energy.
Google discourages reciprocal linking through link directories as it considers them artificial and a form of manipulation. The document provides evidence that Google can detect reciprocal linking and will penalize sites that engage in it by reducing their page rank. The author advises focusing linking efforts on natural linking where sites write about and link to each other organically within articles rather than through direct reciprocity or link directories which provide no value to users.
Jamming Attacks Prevention in Wireless Networks Using Packet Hiding MethodsIOSR Journals
This document discusses selective jamming attacks in wireless networks and methods to prevent them. It begins by introducing the open nature of wireless networks leaves them vulnerable to jamming attacks. It then discusses different types of jamming attacks and notes that selective jamming, which targets specific important packets, is more effective than continuous jamming. The document proposes using cryptographic techniques like commitment schemes and puzzles combined with physical layer parameters to prevent real-time packet classification and selective jamming. It reviews related work on jamming attacks and defenses. Finally, it outlines the problem statement, system model, and the contribution of using symmetric encryption and resisting brute force block encryption attacks to reduce jamming through packet hiding.
Here's the powerpoint of the presentation Nuts&Bold gave to the Museum Computer Network 2013 (#MCN2013).
The first part is all about our inspirations, the second one is the presentation of the process used for Variations, an entirely crowdsourced online exhibit, and the final part is about our current research.
Have fun and if you'd like more info connect yourself to our Facebook page www.facebook.com/nutsandbold.ca or linkedIn or twitter (@nutsbold) or contact us at info@nutsandbold.ca. We will be happy to talk to you some more about our process, the possibilities, etc.
Have fun and let us know what you thinker of the exhibit !
http://commissairesglaneurs.wix.com/variations
nutsandbold.ca
Performance analysis of Fuzzy logic based speed control of DC motorIOSR Journals
The document proposes a fuzzy logic controller to improve the speed control of a separately excited DC motor compared to a conventional PID controller. It designs fuzzy logic membership functions and rules to self-tune the parameters of a PID controller based on motor speed error and change in error. Simulation results show the fuzzy tuned PID controller achieves better dynamic and static response than a conventional PID, with less overshoot, shorter settling time, and smaller steady state error.
Use Email Marketing wisely; Stand out from Junk Mailbelieve52
Email marketing is an effective but cheap way to promote products, however junk mail is common so marketers must stand out. The document provides tips for effective email marketing: 1) use text rather than images to avoid being marked as spam, 2) avoid attachments which can spread viruses, 3) avoid fancy HTML which may not display properly on all email clients, 4) address the recipient by name to increase interest, and 5) provide a valid sender address to avoid being blocked or marked as spam.
Micro-Propagation of Aloe indica L. Through Shoot Tip CultureIOSR Journals
1. Shoot tips of Aloe indica were cultured on MS medium supplemented with various concentrations of cytokinins and auxins to induce shoot proliferation. The highest proliferation of 7.8 shoots per explant was achieved on medium containing 2 mg/L BA and 0.5 mg/L NAA.
2. Rooting was highest (5.2 roots per explant) on medium with 0.5 mg/L NAA. Activated charcoal was added to the medium to prevent browning.
3. The most effective shooting and rooting media were identified as MS medium supplemented with 2mg/L BA + 0.5 mg/L NAA and 0.5 mg/L NAA,
The document discusses building a personal brand through 4 steps: 1) Determine your appeal by listing descriptive words for your personality and qualities. 2) Determine your description by developing a descriptive modifier. 3) Determine your function by writing what you do or will do in your career. 4) Put it all together into a short phrase or sentence no more than 5 words that combines the previous lists. Developing a personal brand enhances self-awareness, narrows goals, helps one stand out, and breathes new life into career documents like resumes and LinkedIn profiles.
A Video Watermarking Scheme to Hinder Camcorder PiracyIOSR Journals
This document describes a video watermarking scheme to prevent camcorder piracy in movie theaters. The scheme embeds watermarks in video frames so that any compliant video player cannot play the video if recorded in a theater. The watermarking technique is robust to geometric distortions like rotation and scaling. It also prevents loss of quality from lossy compression formats. The scheme uses an integer wavelet transform for the watermark embedding and extraction processes, making it computationally efficient and lossless. Experimental results show the scheme can withstand various attacks like filtering, noise addition, resizing and rotation while accurately extracting the embedded watermarks.
Angular and position stability of a nanorod trapped in an optical tweezersAmélia Moreira
The document summarizes the analysis of angular and position stability of a nanorod trapped in an optical tweezers. It computes the optical trapping forces and torques on a nano-cylinder using T-matrix and radiation stress integration approaches. The results show that lateral forces are several times stronger than axial forces, and lateral torques are 1-2 orders stronger than end-face torques. Torques due to surface stress are much stronger than spin torques. The analysis explains why low aspect ratio nanorods are stably trapped normal to the beam axis.
Using resonant ultrasound spectroscopy (RUS), the author will determine the complete elastic constant matrices of two thermoelectric single crystal samples, Ce.75Fe3CoSb12 and CeFe4Sb12. RUS involves measuring the resonant frequencies of a sample's vibrations, which depend on the sample's elastic constants, shape, orientation, and density. The author aims to obtain the elastic moduli from a single RUS spectrum for each sample. Understanding the elastic properties may help identify better thermoelectric materials by correlating low elastic stiffness with low thermal conductivity and higher thermoelectric efficiency. The author will compute the resonant frequencies using the samples' properties and compare to measurements.
This document summarizes an experiment that measured the temperature-dependent responsivity of plasmonic terahertz detectors. The experiment measured the response of gallium nitride chips under terahertz pulses in both free space and liquid nitrogen conditions. The results showed lower response amplitudes in liquid nitrogen, consistent with decreased electron excitation and conductivity at lower temperatures according to plasmonics and semiconductor physics models. Understanding these material properties allows for optimizing devices that use plasmonic materials.
This document discusses plans for the UCNτ Collaboration to measure the neutron lifetime to a precision of 0.1 seconds using a magneto-gravitational trap. In the short term, the collaboration aims to build a prototype trap at Los Alamos National Laboratory to achieve 1 second precision in 6 hours of data collection. Long term goals include collecting data for 1-2 months to reach 0.1 second precision. The collaboration will also investigate systematic effects and detector performance. A neutron lifetime workshop in November 2012 will develop a strategy and potential proposal for this experiment.
Numerical Simulation of 퐒퐢ퟏ−퐱퐆퐞퐱 Thin Film Solar Cell Using AMPS - 1DIOSR Journals
This document describes a numerical simulation of thin film silicon-germanium solar cells using the AMPS-1D simulation program. The simulation varied the germanium concentration in the intrinsic layer between 0-100% to determine the optimal band gap for maximum efficiency. The results showed that a germanium concentration of 90% produced the highest efficiency of 19.68% for device thicknesses under 6 micrometers. Above 6 micrometers, pure silicon performed equally well or better than silicon-germanium alloys.
Unknown 2019 - expand “explorations at and beyond the neutron dripline ”LinhBui343479
The EXPAND project aims to investigate the structure of light neutron-rich nuclei near and beyond the neutron dripline using the RIBF facility at RIKEN. It focuses on augmenting the neutron detection capabilities of the existing SAMURAI setup by transforming the two-wall NEBULA array into the NEBULA-Plus four-wall array. This will enable the routine detection of 3 and 4 neutrons and significantly increase single and two-neutron detection efficiencies. The project has faced delays and budget issues but now plans to equip 60-70 of the 90 acquired scintillator modules for NEBULA-Plus within the existing budget to provide significant gains in neutron detection capabilities.
The characteristics of SecondaryCharged Particlesproduced in 4.5 A GeV/c 28Si...IOSR Journals
To study the characteristics of secondary charged particles produced in 4.5GeV/c 28Si-nucleus interactions a lot of rigorous attempts have been made. The results reveal that the multiplicity correlations are not linear. The findings do not agree with those reported by several earlier workers. However, these correlations may be reproduced quite well by second order polynomial. It is also observed that the dependence of mean normalized, RA and reduced multiplicity, RS on the multiplicity of different charged secondaries is linear up to a certain value and then acquire almost a constant value. Results also reveal that the Kth root of central moment increases with the increase of <ns> and the values of normalized moments do not depend on the nature and the energy of the projectiles. Finally, it is observed that the integral multiplicity distribution of heavily ionizing tracks provide a method for selecting the disintegrations caused by the projectile due to different target nuclei of nuclear emulsion.
Thermoelectric Power Studies of Ni-Co Nano Ferrites Synthesized By Citrate-Ge...IOSR Journals
This document reports on a study of the thermoelectric power of nickel-cobalt nanoferrites with the chemical formula Ni1-xCoxFe2O4 (where x = 0, 0.2, 0.4, 0.6, 0.8, 1.0) synthesized using the citrate-gel auto combustion method. X-ray diffraction analysis confirmed the formation of a single cubic spinel phase without impurities. Lattice parameters increased with increasing cobalt content due to the larger ionic radius of Co2+ ions compared to Ni2+ ions. Seebeck coefficient measurements from 320K to above the Curie temperature showed that the materials behaved as n-type semiconductors and the
Hanle Effect Measurements of Spin Lifetime in Zn0.4Cd0.6Se Epilayers Grown on...Oleg Maksimov
This document summarizes a study that used the Hanle effect to measure spin lifetimes in ZnCdSe epilayers grown on InP substrates with varying n-doping levels. Four samples were studied: three Zn0.4Cd0.6Se samples with carrier densities of 8.0×1016 cm-3, 4.3×1017 cm-3, and 1.1×1018 cm-3, as well as an undoped Zn0.5Cd0.5Se sample. Measurements showed that spin lifetime varied non-monotonically with carrier density, reaching a maximum of ~10.5 ns for the sample near the metal-insulator transition.
This document discusses NMIJ's realization of the kilogram based on the new definition that will link it to the Planck constant. It describes NMIJ's measurements of a 28Si-enriched crystal sphere using an optical interferometer to measure volume, X-ray photoelectron spectroscopy and ellipsometry to characterize the surface, and determination of the sphere's mass based on these measurements and the Planck constant value from CODATA. The mass was realized with a relative standard uncertainty of 2.4 × 10-8. This paper provides details of NMIJ's measurements, data analysis, and uncertainty budget for its participation in an international pilot study comparing realizations of the new kilogram definition by different national metrology instit
Nuclear physics covers many topics including the discovery of the nucleus, nuclear properties, nuclear binding energies, radioactivity, and nuclear models. Rutherford's gold foil experiment in 1911 provided evidence for the small, dense nucleus by detecting alpha particles scattered at large angles. The nucleus was found to be about 100,000 times smaller than the atom but containing almost all of its mass. Nuclear binding energy refers to the energy required to separate a nucleus into its constituent protons and neutrons and provides a measure of nuclear stability, with the most tightly bound nuclei having the greatest binding energy per nucleon.
IMPROVEMENT IN MORPHOLOGICAL AND ELECTRO-MAGNETIC BEHAVIOUR OF HARD FERRITE P...Editor IJMTER
The Ni-Ir substituted strontium ferrite of Sr(Ni-Ir)xFe12-2xO19 (x = 0.02 & 0.08) were
synthesized by sol-gel auto combustion technique and characterized using X-ray diffraction (XRD),
Transmission Electron Microscopy (TEM) for morphological behaviour with electrical
characteristics using Impedance Analyzer. XRD results confirmed the formation of a single phase
M-type hexagonal unit cell of space group P63/mmc. The increase in Ni-Ir concentration increases
the lattice parameter. TEM analysis of the sample demonstrates the formation of nano-size particles
which decreases with substitution. In this paper we reported the variation of dielectric constant,
dielectric loss, tangent loss, conductivity and magnetic behaviour with composition with temperature
and frequency analysis of the sample. The migration of Fe3+ ion from octahedral to tetrahedral site
decreases the dielectric constant with increase in Ni-Ir concentration. Activation energies were
found similar with calculated at ferromagnetic and paramagnetic region. The material study we
confined that the activation energy in the paramagnetic region is higher than that in the
ferromagnetic region. The enhanced resistivity of Ni-Ir substituted strontium hexaferrites is a
prospective application in high frequency and in microwave devices development.
The document provides an overview of the nuclear shell model. It discusses the historical development of the model from 1927 to 1935. It then presents three pieces of evidence from experiments that supported developing the shell model to describe nuclear properties, including excitation energies, neutron absorption cross-sections, and neutron separation energies. The rest of the document outlines how the shell model was developed theoretically by introducing a Woods-Saxon potential well and spin-orbit coupling to explain nuclear magic numbers and properties like ground and excited state configurations and nuclear magnetic moments. The model provides good predictions but has some limitations for deformed nuclei.
Elastic scattering reaction of on partial wave scattering matrix, differentia...Alexander Decker
This document analyzes the elastic scattering reaction of helium-4 and boron-10 at laboratory energies of 5-15 MeV using an optical model. The optical model approximates the interaction between projectile and target nuclei as a complex optical potential. Six optical parameters describe this potential, including the depth, Coulomb radius, and diffuseness of the real and imaginary parts. Five of the parameters were varied to calculate the partial wave scattering matrix, differential cross section, and reaction cross section ratio to the Rutherford cross section. The results provide angular distributions of the reaction cross sections and differential cross sections from center-of-mass angles of 0-180 degrees for energies of 5, 7, 12, and 15 MeV.
Computational electromagnetics in plasmonic nanostructuresAliakbarMonfared1
This document summarizes computational methods for simulating the optical response of plasmonic nanostructures, specifically focusing on finite-difference time-domain (FDTD), finite element method (FEM), discrete dipole approximation (DDA), and boundary element method (BEM). It discusses these numerical approaches from both theoretical and practical perspectives. FDTD is described as explicitly calculating electric and magnetic fields on a grid over time to solve Maxwell's equations. Its applications include simulating optical properties and enhancing solar cell efficiency by tuning nanoparticle geometry. The document provides several examples of research using FDTD for these purposes.
This document discusses problems and solutions related to the physics of semiconductor devices. It covers topics such as properties of semiconductors, Schottky diodes, p-n junctions, solar cells, bipolar transistors, MOS capacitors and MOSFETs, low-dimensional structures, and LEDs and lasers. For each topic, it lists specific problems and provides detailed solutions and calculations in the answers and solutions section. The overall document serves as a comprehensive reference for understanding the physics behind key semiconductor devices.
A New Hybrid Inversion Method For 2D Nuclear Magnetic Resonance Combining TSV...Pedro Craggett
This paper presents a new hybrid method for inverting 2D nuclear magnetic resonance (NMR) data that combines truncated singular value decomposition (TSVD) and Tikhonov regularization. The method computes the exact TSVD of the kernel matrix using its Kronecker product structure, avoiding approximations. It then solves a Tikhonov-like optimization problem using the truncated kernel. The paper also proposes using the Discrete Picard Condition to automatically select both the TSVD truncation index and Tikhonov regularization parameter. The performance of the new hybrid method is evaluated on simulated and real NMR data.
The document provides an introduction to basic concepts in nuclear physics, including:
- Binding energy and the liquid drop model, which describes the saturation of nuclear forces.
- Nuclear dimensions and the different energy scales involved.
- The Fermi gas model, which treats nuclei as two fermion gases and can provide constants for binding energy formulas.
- The shell model, which incorporates a mean field potential and spin-orbit potential to reproduce shell structure in nuclei.
- Isospin, which treats protons and neutrons as states of a single particle to explain similarities in their behavior.
This document provides a technical review of secure banking using RSA and AES encryption methodologies. It discusses how RSA and AES are commonly used encryption standards for secure data transmission between ATMs and bank servers. The document first provides background on ATM security measures and risks of attacks. It then reviews related work analyzing encryption techniques. The document proposes using a one-time password in addition to a PIN for ATM authentication. It concludes that implementing encryption standards like RSA and AES can make transactions more secure and build trust in online banking.
This document analyzes the performance of various modulation schemes for achieving energy efficient communication over fading channels in wireless sensor networks. It finds that for long transmission distances, low-order modulations like BPSK are optimal due to their lower SNR requirements. However, as transmission distance decreases, higher-order modulations like 16-QAM and 64-QAM become more optimal since they can transmit more bits per symbol, outweighing their higher SNR needs. Simulations show lifetime extensions up to 550% are possible in short-range networks by using higher-order modulations instead of just BPSK. The optimal modulation depends on transmission distance and balancing the energy used by electronic components versus power amplifiers.
This document provides a review of mobility management techniques in vehicular ad hoc networks (VANETs). It discusses three modes of communication in VANETs: vehicle-to-infrastructure (V2I), vehicle-to-vehicle (V2V), and hybrid vehicle (HV) communication. For each communication mode, different mobility management schemes are required due to their unique characteristics. The document also discusses mobility management challenges in VANETs and outlines some open research issues in improving mobility management for seamless communication in these dynamic networks.
This document provides a review of different techniques for segmenting brain MRI images to detect tumors. It compares the K-means and Fuzzy C-means clustering algorithms. K-means is an exclusive clustering algorithm that groups data points into distinct clusters, while Fuzzy C-means is an overlapping clustering algorithm that allows data points to belong to multiple clusters. The document finds that Fuzzy C-means requires more time for brain tumor detection compared to other methods like hierarchical clustering or K-means. It also reviews related work applying these clustering algorithms to segment brain MRI images.
1) The document simulates and compares the performance of AODV and DSDV routing protocols in a mobile ad hoc network under three conditions: when users are fixed, when users move towards the base station, and when users move away from the base station.
2) The results show that both protocols have higher packet delivery and lower packet loss when users are either fixed or moving towards the base station, since signal strength is better in those scenarios. Performance degrades when users move away from the base station due to weaker signals.
3) AODV generally has better performance than DSDV, with higher throughput and packet delivery rates observed across the different user mobility conditions.
This document describes the design and implementation of 4-bit QPSK and 256-bit QAM modulation techniques using MATLAB. It compares the two techniques based on SNR, BER, and efficiency. The key steps of implementing each technique in MATLAB are outlined, including generating random bits, modulation, adding noise, and measuring BER. Simulation results show scatter plots and eye diagrams of the modulated signals. A table compares the results, showing that 256-bit QAM provides better performance than 4-bit QPSK. The document concludes that QAM modulation is more effective for digital transmission systems.
The document proposes a hybrid technique using Anisotropic Scale Invariant Feature Transform (A-SIFT) and Robust Ensemble Support Vector Machine (RESVM) to accurately identify faces in images. A-SIFT improves upon traditional SIFT by applying anisotropic scaling to extract richer directional keypoints. Keypoints are processed with RESVM and hypothesis testing to increase accuracy above 95% by repeatedly reprocessing images until the threshold is met. The technique was tested on similar and different facial images and achieved better results than SIFT in retrieval time and reduced keypoints.
This document studies the effects of dielectric superstrate thickness on microstrip patch antenna parameters. Three types of probes-fed patch antennas (rectangular, circular, and square) were designed to operate at 2.4 GHz using Arlondiclad 880 substrate. The antennas were tested with and without an Arlondiclad 880 superstrate of varying thicknesses. It was found that adding a superstrate slightly degraded performance by lowering the resonant frequency and increasing return loss and VSWR, while decreasing bandwidth and gain. Specifically, increasing the superstrate thickness or dielectric constant resulted in greater changes to the antenna parameters.
This document describes a wireless environment monitoring system that utilizes soil energy as a sustainable power source for wireless sensors. The system uses a microbial fuel cell to generate electricity from the microbial activity in soil. Two microbial fuel cells were created using different soil types and various additives to produce different current and voltage outputs. An electronic circuit was designed on a printed circuit board with components like a microcontroller and ZigBee transceiver. Sensors for temperature and humidity were connected to the circuit to monitor the environment wirelessly. The system provides a low-cost way to power remote sensors without needing battery replacement and avoids the high costs of wiring a power source.
1) The document proposes a model for a frequency tunable inverted-F antenna that uses ferrite material.
2) The resonant frequency of the antenna can be significantly shifted from 2.41GHz to 3.15GHz, a 31% shift, by increasing the static magnetic field placed on the ferrite material.
3) Altering the permeability of the ferrite allows tuning of the antenna's resonant frequency without changing the physical dimensions, providing flexibility to operate over a wide frequency range.
This document summarizes a research paper that presents a speech enhancement method using stationary wavelet transform. The method first classifies speech into voiced, unvoiced, and silence regions based on short-time energy. It then applies different thresholding techniques to the wavelet coefficients of each region - modified hard thresholding for voiced speech, semi-soft thresholding for unvoiced speech, and setting coefficients to zero for silence. Experimental results using speech from the TIMIT database corrupted with white Gaussian noise at various SNR levels show improved performance over other popular denoising methods.
This document reviews the design of an energy-optimized wireless sensor node that encrypts data for transmission. It discusses how sensing schemes that group nodes into clusters and transmit aggregated data can reduce energy consumption compared to individual node transmissions. The proposed node design calculates the minimum transmission power needed based on received signal strength and uses a periodic sleep/wake cycle to optimize energy when not sensing or transmitting. It aims to encrypt data at both the node and network level to further optimize energy usage for wireless communication.
This document discusses group consumption modes. It analyzes factors that impact group consumption, including external environmental factors like technological developments enabling new forms of online and offline interactions, as well as internal motivational factors at both the group and individual level. The document then proposes that group consumption modes can be divided into four types based on two dimensions: vertical (group relationship intensity) and horizontal (consumption action period). These four types are instrument-oriented, information-oriented, enjoyment-oriented, and relationship-oriented consumption modes. Finally, the document notes that consumption modes are dynamic and can evolve over time.
The document summarizes a study of different microstrip patch antenna configurations with slotted ground planes. Three antenna designs were proposed and their performance evaluated through simulation: a conventional square patch, an elliptical patch, and a star-shaped patch. All antennas were mounted on an FR4 substrate. The effects of adding different slot patterns to the ground plane on resonance frequency, bandwidth, gain and efficiency were analyzed parametrically. Key findings were that reshaping the patch and adding slots increased bandwidth and shifted resonance frequency. The elliptical and star patches in particular performed better than the conventional design. Three antenna configurations were selected for fabrication and measurement based on the simulations: a conventional patch with a slot under the patch, an elliptical patch with slots
1) The document describes a study conducted to improve call drop rates in a GSM network through RF optimization.
2) Drive testing was performed before and after optimization using TEMS software to record network parameters like RxLevel, RxQuality, and events.
3) Analysis found call drops were occurring due to issues like handover failures between sectors, interference from adjacent channels, and overshooting due to antenna tilt.
4) Corrective actions taken included defining neighbors between sectors, adjusting frequencies to reduce interference, and lowering the mechanical tilt of an antenna.
5) Post-optimization drive testing showed improvements in RxLevel, RxQuality, and a reduction in dropped calls.
This document describes the design of an intelligent autonomous wheeled robot that uses RF transmission for communication. The robot has two modes - automatic mode where it can make its own decisions, and user control mode where a user can control it remotely. It is designed using a microcontroller and can perform tasks like object recognition using computer vision and color detection in MATLAB, as well as wall painting using pneumatic systems. The robot's movement is controlled by DC motors and it uses sensors like ultrasonic sensors and gas sensors to navigate autonomously. RF transmission allows communication between the robot and a remote control unit. The overall aim is to develop a low-cost robotic system for industrial applications like material handling.
This document reviews cryptography techniques to secure the Ad-hoc On-Demand Distance Vector (AODV) routing protocol in mobile ad-hoc networks. It discusses various types of attacks on AODV like impersonation, denial of service, eavesdropping, black hole attacks, wormhole attacks, and Sybil attacks. It then proposes using the RC6 cryptography algorithm to secure AODV by encrypting data packets and detecting and removing malicious nodes launching black hole attacks. Simulation results show that after applying RC6, the packet delivery ratio and throughput of AODV increase while delay decreases, improving the security and performance of the network under attack.
The document describes a proposed modification to the conventional Booth multiplier that aims to increase its speed by applying concepts from Vedic mathematics. Specifically, it utilizes the Urdhva Tiryakbhyam formula to generate all partial products concurrently rather than sequentially. The proposed 8x8 bit multiplier was coded in VHDL, simulated, and found to have a path delay 44.35% lower than a conventional Booth multiplier, demonstrating its potential for higher speed.
This document discusses image deblurring techniques. It begins by introducing image restoration and focusing on image deblurring. It then discusses challenges with image deblurring being an ill-posed problem. It reviews existing approaches to screen image deconvolution including estimating point spread functions and iteratively estimating blur kernels and sharp images. The document also discusses handling spatially variant blur and summarizes the relationship between the proposed method and previous work for different blur types. It proposes using color filters in the aperture to exploit parallax cues for segmentation and blur estimation. Finally, it proposes moving the image sensor circularly during exposure to prevent high frequency attenuation from motion blur.
This document describes modeling an adaptive controller for an aircraft roll control system using PID, fuzzy-PID, and genetic algorithm. It begins by introducing the aircraft roll control system and motivation for developing an adaptive controller to minimize errors from noisy analog sensor signals. It then provides the mathematical model of aircraft roll dynamics and describes modeling the real-time flight control system in MATLAB/Simulink. The document evaluates PID, fuzzy-PID, and PID-GA (genetic algorithm) controllers for aircraft roll control and finds that the PID-GA controller delivers the best performance.
5th LF Energy Power Grid Model Meet-up SlidesDanBrown980551
5th Power Grid Model Meet-up
It is with great pleasure that we extend to you an invitation to the 5th Power Grid Model Meet-up, scheduled for 6th June 2024. This event will adopt a hybrid format, allowing participants to join us either through an online Mircosoft Teams session or in person at TU/e located at Den Dolech 2, Eindhoven, Netherlands. The meet-up will be hosted by Eindhoven University of Technology (TU/e), a research university specializing in engineering science & technology.
Power Grid Model
The global energy transition is placing new and unprecedented demands on Distribution System Operators (DSOs). Alongside upgrades to grid capacity, processes such as digitization, capacity optimization, and congestion management are becoming vital for delivering reliable services.
Power Grid Model is an open source project from Linux Foundation Energy and provides a calculation engine that is increasingly essential for DSOs. It offers a standards-based foundation enabling real-time power systems analysis, simulations of electrical power grids, and sophisticated what-if analysis. In addition, it enables in-depth studies and analysis of the electrical power grid’s behavior and performance. This comprehensive model incorporates essential factors such as power generation capacity, electrical losses, voltage levels, power flows, and system stability.
Power Grid Model is currently being applied in a wide variety of use cases, including grid planning, expansion, reliability, and congestion studies. It can also help in analyzing the impact of renewable energy integration, assessing the effects of disturbances or faults, and developing strategies for grid control and optimization.
What to expect
For the upcoming meetup we are organizing, we have an exciting lineup of activities planned:
-Insightful presentations covering two practical applications of the Power Grid Model.
-An update on the latest advancements in Power Grid -Model technology during the first and second quarters of 2024.
-An interactive brainstorming session to discuss and propose new feature requests.
-An opportunity to connect with fellow Power Grid Model enthusiasts and users.
For the full video of this presentation, please visit: https://www.edge-ai-vision.com/2024/06/how-axelera-ai-uses-digital-compute-in-memory-to-deliver-fast-and-energy-efficient-computer-vision-a-presentation-from-axelera-ai/
Bram Verhoef, Head of Machine Learning at Axelera AI, presents the “How Axelera AI Uses Digital Compute-in-memory to Deliver Fast and Energy-efficient Computer Vision” tutorial at the May 2024 Embedded Vision Summit.
As artificial intelligence inference transitions from cloud environments to edge locations, computer vision applications achieve heightened responsiveness, reliability and privacy. This migration, however, introduces the challenge of operating within the stringent confines of resource constraints typical at the edge, including small form factors, low energy budgets and diminished memory and computational capacities. Axelera AI addresses these challenges through an innovative approach of performing digital computations within memory itself. This technique facilitates the realization of high-performance, energy-efficient and cost-effective computer vision capabilities at the thin and thick edge, extending the frontier of what is achievable with current technologies.
In this presentation, Verhoef unveils his company’s pioneering chip technology and demonstrates its capacity to deliver exceptional frames-per-second performance across a range of standard computer vision networks typical of applications in security, surveillance and the industrial sector. This shows that advanced computer vision can be accessible and efficient, even at the very edge of our technological ecosystem.
Connector Corner: Seamlessly power UiPath Apps, GenAI with prebuilt connectorsDianaGray10
Join us to learn how UiPath Apps can directly and easily interact with prebuilt connectors via Integration Service--including Salesforce, ServiceNow, Open GenAI, and more.
The best part is you can achieve this without building a custom workflow! Say goodbye to the hassle of using separate automations to call APIs. By seamlessly integrating within App Studio, you can now easily streamline your workflow, while gaining direct access to our Connector Catalog of popular applications.
We’ll discuss and demo the benefits of UiPath Apps and connectors including:
Creating a compelling user experience for any software, without the limitations of APIs.
Accelerating the app creation process, saving time and effort
Enjoying high-performance CRUD (create, read, update, delete) operations, for
seamless data management.
Speakers:
Russell Alfeche, Technology Leader, RPA at qBotic and UiPath MVP
Charlie Greenberg, host
How information systems are built or acquired puts information, which is what they should be about, in a secondary place. Our language adapted accordingly, and we no longer talk about information systems but applications. Applications evolved in a way to break data into diverse fragments, tightly coupled with applications and expensive to integrate. The result is technical debt, which is re-paid by taking even bigger "loans", resulting in an ever-increasing technical debt. Software engineering and procurement practices work in sync with market forces to maintain this trend. This talk demonstrates how natural this situation is. The question is: can something be done to reverse the trend?
Main news related to the CCS TSI 2023 (2023/1695)Jakub Marek
An English 🇬🇧 translation of a presentation to the speech I gave about the main changes brought by CCS TSI 2023 at the biggest Czech conference on Communications and signalling systems on Railways, which was held in Clarion Hotel Olomouc from 7th to 9th November 2023 (konferenceszt.cz). Attended by around 500 participants and 200 on-line followers.
The original Czech 🇨🇿 version of the presentation can be found here: https://www.slideshare.net/slideshow/hlavni-novinky-souvisejici-s-ccs-tsi-2023-2023-1695/269688092 .
The videorecording (in Czech) from the presentation is available here: https://youtu.be/WzjJWm4IyPk?si=SImb06tuXGb30BEH .
Taking AI to the Next Level in Manufacturing.pdfssuserfac0301
Read Taking AI to the Next Level in Manufacturing to gain insights on AI adoption in the manufacturing industry, such as:
1. How quickly AI is being implemented in manufacturing.
2. Which barriers stand in the way of AI adoption.
3. How data quality and governance form the backbone of AI.
4. Organizational processes and structures that may inhibit effective AI adoption.
6. Ideas and approaches to help build your organization's AI strategy.
Discover top-tier mobile app development services, offering innovative solutions for iOS and Android. Enhance your business with custom, user-friendly mobile applications.
Dandelion Hashtable: beyond billion requests per second on a commodity serverAntonios Katsarakis
This slide deck presents DLHT, a concurrent in-memory hashtable. Despite efforts to optimize hashtables, that go as far as sacrificing core functionality, state-of-the-art designs still incur multiple memory accesses per request and block request processing in three cases. First, most hashtables block while waiting for data to be retrieved from memory. Second, open-addressing designs, which represent the current state-of-the-art, either cannot free index slots on deletes or must block all requests to do so. Third, index resizes block every request until all objects are copied to the new index. Defying folklore wisdom, DLHT forgoes open-addressing and adopts a fully-featured and memory-aware closed-addressing design based on bounded cache-line-chaining. This design offers lock-free index operations and deletes that free slots instantly, (2) completes most requests with a single memory access, (3) utilizes software prefetching to hide memory latencies, and (4) employs a novel non-blocking and parallel resizing. In a commodity server and a memory-resident workload, DLHT surpasses 1.6B requests per second and provides 3.5x (12x) the throughput of the state-of-the-art closed-addressing (open-addressing) resizable hashtable on Gets (Deletes).
Conversational agents, or chatbots, are increasingly used to access all sorts of services using natural language. While open-domain chatbots - like ChatGPT - can converse on any topic, task-oriented chatbots - the focus of this paper - are designed for specific tasks, like booking a flight, obtaining customer support, or setting an appointment. Like any other software, task-oriented chatbots need to be properly tested, usually by defining and executing test scenarios (i.e., sequences of user-chatbot interactions). However, there is currently a lack of methods to quantify the completeness and strength of such test scenarios, which can lead to low-quality tests, and hence to buggy chatbots.
To fill this gap, we propose adapting mutation testing (MuT) for task-oriented chatbots. To this end, we introduce a set of mutation operators that emulate faults in chatbot designs, an architecture that enables MuT on chatbots built using heterogeneous technologies, and a practical realisation as an Eclipse plugin. Moreover, we evaluate the applicability, effectiveness and efficiency of our approach on open-source chatbots, with promising results.
Fueling AI with Great Data with Airbyte WebinarZilliz
This talk will focus on how to collect data from a variety of sources, leveraging this data for RAG and other GenAI use cases, and finally charting your course to productionalization.
In the realm of cybersecurity, offensive security practices act as a critical shield. By simulating real-world attacks in a controlled environment, these techniques expose vulnerabilities before malicious actors can exploit them. This proactive approach allows manufacturers to identify and fix weaknesses, significantly enhancing system security.
This presentation delves into the development of a system designed to mimic Galileo's Open Service signal using software-defined radio (SDR) technology. We'll begin with a foundational overview of both Global Navigation Satellite Systems (GNSS) and the intricacies of digital signal processing.
The presentation culminates in a live demonstration. We'll showcase the manipulation of Galileo's Open Service pilot signal, simulating an attack on various software and hardware systems. This practical demonstration serves to highlight the potential consequences of unaddressed vulnerabilities, emphasizing the importance of offensive security practices in safeguarding critical infrastructure.
"Frontline Battles with DDoS: Best practices and Lessons Learned", Igor IvaniukFwdays
At this talk we will discuss DDoS protection tools and best practices, discuss network architectures and what AWS has to offer. Also, we will look into one of the largest DDoS attacks on Ukrainian infrastructure that happened in February 2022. We'll see, what techniques helped to keep the web resources available for Ukrainians and how AWS improved DDoS protection for all customers based on Ukraine experience
[OReilly Superstream] Occupy the Space: A grassroots guide to engineering (an...Jason Yip
The typical problem in product engineering is not bad strategy, so much as “no strategy”. This leads to confusion, lack of motivation, and incoherent action. The next time you look for a strategy and find an empty space, instead of waiting for it to be filled, I will show you how to fill it in yourself. If you’re wrong, it forces a correction. If you’re right, it helps create focus. I’ll share how I’ve approached this in the past, both what works and lessons for what didn’t work so well.
Skybuffer SAM4U tool for SAP license adoptionTatiana Kojar
Manage and optimize your license adoption and consumption with SAM4U, an SAP free customer software asset management tool.
SAM4U, an SAP complimentary software asset management tool for customers, delivers a detailed and well-structured overview of license inventory and usage with a user-friendly interface. We offer a hosted, cost-effective, and performance-optimized SAM4U setup in the Skybuffer Cloud environment. You retain ownership of the system and data, while we manage the ABAP 7.58 infrastructure, ensuring fixed Total Cost of Ownership (TCO) and exceptional services through the SAP Fiori interface.
Deep Dive: AI-Powered Marketing to Get More Leads and Customers with HyperGro...
G0345259
1. IOSR Journal of Applied Physics (IOSR-JAP)
e-ISSN: 2278-4861. Volume 3, Issue 4 (Mar. - Apr. 2013), PP 52-59
www.iosrjournals.org
www.iosrjournals.org 52 | Page
Shell Model Description of N = 51 Isotones
K. Maurya1
, P. C. Srivastava2
, I. Mehrotra1
1
Department of Physics, University of Allahabad, Allahabad-211002, India
2
Instituto de Ciencias Nucleares, Universidad Nacional Aut´onoma de M´exico, Apartado Postal 70-
543, 04510 M´exico, D.F., M´exico
Abstract: Shell model calculations for 83
Ge, 85
Se, 87
Kr, 89
Sr and 91
Zr nuclei which form the N = 51 isotonic
chain have been reported. The calculations have been performed taking 78
Ni as a core and the valence space
comprises of ν(0g7/2, 1d5/2, 1d3/2, 2s1/2, 0h11/2) orbitals for neutrons and π(0f5/2, 1p3/2, 1p1/2, 0g9/2) orbitals for
proton. The effective interaction for the present calculations is based on CD-Bonn N − N potential and adopted
to the model space based on the 78
Ni core. The results of present calculations show that the chosen interaction
does not give a good agreement of the observed spectra with the experimental data for N=51 isotones. However
some general trends of the experimental spectra like increase in the E(1/2+
) ̴ E(5/2+
) energy splitting and
raising of 3/2+
level in going from Z=32 to 40 are well reproduced.
Keywords- Isotones; effective interaction
I. Introduction
With the development of first generation radioactive ion beam facilities over the last decade it is now
possible to access very neutron rich nuclei in few specific regions of the nuclear chart which do not even survive
on the earth. Further, the study of these nuclei is considered as an ideal testing ground for a number of important
issues: e.g. the evolution of shell structure concentrating on the neutron rich regions around Z = 20 and 28,
relation between single particle and collective behavior etc. The study of nuclei with two magic numbers Z = 28
and N = 50 and in its vicinity has already been undertaken for a long time towards and beyond 78
Ni and is still
the objective of active experimental and theoretical research. Previously neutron rich nuclei in the vicinity of
78
Ni have been produced and studied using deuteron beam available at the Tandem Accelerator in Orsay[1].
Since 78Ni is the most neutron rich example of doubly magic nucleus in whole nuclide chart with an extreme
N/Z ratio of 1.79 and further away from the stability on the neutron rich side, this region of nuclide chart
remains extremely hard to reach experimentally. So far, only a dozen of 78
Ni could be successfully synthesized
and identified with most advanced techniques of production of rare isotopes using high energy beam
fragmentation. The most practical method of exploring the 78
Ni region is to study the decay of fission product to
the levels of the N = 50 isotones above 78
Ni [2] and the study of nuclei with few valence particle or holes
provides best testing ground for the basic ingredients of the shell model calculations. So N = 51 nuclide form an
interesting example of nuclei where the variation of the neutron single-particle energies can be investigated and
nuclei in this mass region are particularly important to understand astrophysical processes. Also neutron rich
nuclei between N = 50 and N = 82 shells cover waiting point in r-processes. Properties of low lying states in
these nuclei near closed shell are useful for the description of nuclear structure, quenching of shell gaps and a
more uniform spacing of single-particle energy levels [3,4,5] and influence how heavier nuclei are produced in
astrophysical rapid neutron capture (r−) process [6,7]. A large number of nuclei can be populated by means of
binary reactions such as multinucleon transfer and deep inelastic collisions with a stable beam. Such reactions
combined with modern -detection array have increased substantially the available data on nuclei far from
stability. Recently an experiment has been performed at LNL to study the nature of the low lying yrast or quasi
yrast 7/2+
states in 32 < Z < 40, N = 51 nuclei in order to assess their collective or ν1g7/2 single-particle origin
and better constrain the relative position of the latter with respect to other neutron single-particle states above a
78
Ni core [8].
In the present work we have chosen N = 51 isotone nuclide viz. 83
Ge, 85
Se, 87
Kr, 89
Sr and 91
Zr which
form an interesting region to study the validity of nuclear shell model in modeling of the available nuclear data
[9,10]. Recently single neutron transfer reaction have been measured on two N= 50 isotones at HRIBF. The
single particle like states of 83
Ge and 85
Se have been populated using radioactive ion beams of 82
Ge and 84
Se and
the (d, p) reaction in inverse kinematics. This experiment has provided data on level structure of 83
Ge and 85
Se
[9] including data on 87
Kr, 89
Sr and 91
Zr with references therein.
The nuclear shell model is the most powerful tool for giving a quantitative interpretation to the
experimental data. Our recent shell-model (SM) studies for neutron-rich F isotopes [11], odd and even isotopes
of Fe [12,13], odd-odd Mn isotopes [14] odd-mass 61,63,65
Co isotopes [15], even-even Ni and Zn and odd-A Cu
isotopes [16,17], odd-mass Ga isotopes [18] and neutron deficient 102−108
Sn isotopes [19] have shown that the
2. Shell Model Description of N = 51 Isotones
www.iosrjournals.org 53 | Page
shell model calculations, carried out in an extended configuration space with suitably renormalized effective
interaction, give a satisfactory account of the experimental data of unstable nuclei. Following this in the present
work we have performed large scale shell model calculation for neutron rich 83
Ge, 85
Se, 87
Kr, 89
Sr and 91
Zr
nuclei which form the N = 51 isotonic chain. The effective interaction used in the present work is renormalized
G matrix obtained from CD Bonn N-N interaction and adopted to the model space based on a 78
Ni core (referred
to as jj45pna interaction). Earlier jj45pna interaction has been used in the study of 128
Cd [20] and its monopole
corrected version in the study of Zr isotopes in this region [21]. G-matrix derived from CD-Bonn potential have
also been widely used in the theoretical calculations performed by the Oslo group and their coworkers in 132
Sn
region [22,23,24,25,26].
The aim of this work is to test the suitability of the model space and the effective interaction in
interpreting the experimental data of these highly unstable nuclei on the neutron rich side. The paper is
organized as follows: section 2 gives details of the calculation. Results and discussion are given in section 3.
Finally in section 4 conclusions are given.
II. Details of Calculation
2.1. Configuration Space
Large scale shell model calculations have been performed for even Z neutron-rich N = 51 isotones in
mass region A=83 - 91 treating 78
Ni as a core. The configuration space comprises of ν(0g7/2, 1d5/2, 1d3/2, 2s1/2,
0h11/2) orbitals for neutrons and π(0f5/2, 1p3/2, 1p1/2, 0g9/2) orbitals for protons with all Pauli allowed
combinations of valence particles. The calculated single particle energies for model space π(0f5/2, 1p3/2, 1p1/2,
0g9/2) and ν(0g7/2, 1d5/2, 1d3/2, 2s1/2, 0h11/2) are respectively -0.7166, 1.1184, 1.1262 and 0.1785 MeV for proton
orbitals and 5.7402, 2.4422, 2.5148, 2.1738 and 2.6795 MeV for neutron orbitals.
2.2. Effective Interaction
The calculations have been performed with a state of art effective interaction (jj45pna) derived from
high precision, charge dependent version of Bonn N-N potential, known as CD-Bonn potential, see ref.[27]. The
parameter of the potential fit the proton- proton and neutron-proton data available till 2000 with χ2
per datum
close to 1. This high precision is obtained by the introduction of the two effective σ mesons the parameters of
which are partial wave dependent. The charge dependence of the CD-Bonn potential is based upon the
predictions by the Bonn full model[28] for charge symmetry and charge independence breaking in all partial
wave with J ≤ 4. The strong short range repulsion is overcome by Brueckner (reaction) G-matrix
renormalization which accounts for the effects of two nucleon correlations [29]. The jj45pna effective
interaction has been obtained by adopting G-matrix to the chosen model space above the 78
Ni core by using
many body perturbation technique.
2.3. Computer Code
The calculations have been performed with the code NuShell [30]. It comes with a library of model
spaces and interactions. This shell model code has been developed by Alex Brown from MSU to tackle the
dimensions up to 106
in the J − T scheme and about 2x107
in m-scheme. NuShell generates the basis states in m-
scheme and then computes the matrix in j-scheme. Therefore, it bypasses the complication of angular
momentum algebra in j − j coupled basis and also avoids the huge matrix dimension generated during m-
scheme. NuShell consists of seven main programs and some supporting codes.
III. Results and Discussion
3.1. Excitation Energies
The results of our calculations for different isotones are shown in Figs 1-5 along with the experimental
data for comparison . The excited states up to 2.5 MeV have been calculated. Experimentally it is well
established that the ν1d5/2 subshell is the ground state for all the isotones considered here i.e. 1d5/2 is first
valence orbit above the N=50 shell gap which is well reproduced in our results for all isotones. Our calculations
predict 1/2+
as the first excited state in agreement with the experimental data for all the isotones considered,
except for 91
Zr in which 7/2+
state is predicted as the first excited state and 1/2+
state lies slightly higher. The
predicted E(1/2+
) state lies lower than the corresponding experimental values in all the cases. The special feature
of the experimental energy spectra of N = 51 isotones is increase in the E(1/2+
) ̴ E(5/2+
) splitting in going from
Z= 32 to Z=40. This trend is also reproduced in the theoretical spectra.
The variation of the excitation energy of first 1/2+
state with proton number is shown in Fig 6. If
energies relative to the 2s1/2 are considered, the monopole residual interaction between spin-flip ∆ℓ=1 pair of
0f5/2 proton orbital and 1d5/2 neutron orbital could be lowering 1d5/2 excitation with respect to 2s1/2 orbital as the
stable 89
Sr and 91
Zr are approached. Since 1/2+
level is attributed to the excitation of neutron to 2s1/2 level, this
variation of E(1/2+
) with filling of proton orbitals is a signature of monopole effect [9,10]. Alternatively the
3. Shell Model Description of N = 51 Isotones
www.iosrjournals.org 54 | Page
raising of the 2s1/2 orbital in neutron rich N=51 isotones could be evidence for a reduced diffuseness of the
nuclear suface, which preferentially raises 2s1/2 orbitals relative to the increased binding of lower j-states [31].
In all the isotones with the exception of 91
Zr, the 7/2+
level is predicted to lie higher than the 3/2+
level contrary
to the experimental results. 7/2+
state for 85
Se and 87
Kr have small deviations from corresponding experimental
values. For 83
Ge its value is too high and for 89
Sr and 91
Zr its value is too low in comparison to the experimental
data. So this interaction gives poor results for 7/2+
state. It finally becomes first excited state for 91
Zr. This
indicates that the considered model space is not enough for 91
Zr.. Rising trend of calculated E(3/2+
) values with
increasing Z is supported by the experimental data although their values are comparatively low. 7/2+
state is
single particle energy in nature with weaker amount of mixing of neutron single particle 0g7/2 with coupled
configuration. On the other hand 3/2+
state is single particle energy in nature with partial mixing of neutron
single particle 1d3/2 with coupled configuration [32]. Single particle energies used in our calculations are 5.7402
for 0g7/2 and 2.5148 for 1d3/2. The calculated levels are sensitive to the single particle energies of the neutron
orbitals which in turn get renormalized due to the monopole correction. Thus use of effective single particle
energies can change the results.
The agreement of the E(9/2+
) with experimental data for 89
Sr and 91
Zr is reasonably good. For 87
Kr and
85
Se Theoretical E(9/2+
) levels lie higher as compared to the corresponding experimental values but rising trend
of E(9/2+
) state with increasing Z shows the nearly correct systematic for all nuclei. The experimental data for
E(9/2+
) state for 83
Ge is not available and theoretically predicted value is 1.856 MeV. The 9/2+
state is likely to
have a rather pure coupled configuration ν1d5/2 ⊗ 2+
, as 0g9/2 orbit is too deeply bound (by about 3.5 MeV) to
give a fraction of single particle state at low energy . Such a configuration for the 9/2+
state is confirmed by the
fact that its energy follows closely that of the 2+
state [33].
The discrepancy between the calculated values and the experimental data can also be attributed to the
core excitation effect and neglect of contributions arising due to 3N forces [34] . The coupling of the ν1d5/2
orbit to the first 2+
excitation of the core provides a multiplet of states with spin between 1/2+
and 9/2+
.
Therefore the 1/2+
, 3/2+
and 7/2+
states originating from the 2s1/2,1d3/2 and 0g7/2 orbits can be mixed to those
obtained with the coupling to the core excitation. But experimentally 1/2+
and 7/2+
significantly depart from that
of 2+
core indicating that their composition is likely to be mostly of single particle origin with a weaker amount
of mixing with the coupled configuration. So they are originating mainly from 2s1/2 and 0g7/2 subshell [33] and
observed as first and second excited state experimentally. While 3/2+
state close to one of 2+
state of core [10] is
originating with a partial mixing of neutron single particle state 1d3/2 with coupled configuration [32]. Recent
studies [35-37] have shown that 3N forces play an important role in the evolution of shell structure in neutron
rich nuclei. Explicit calculations carried out for neutron rich light mass oxygen [35] and medium mass calcium
isotopes [36] have shown that 3N forces add a repulsive term to the monopole component of the two nucleon
interaction and are key to explain the doubly magic nature of 24
O and 48
Ca nuclei. Inclusion of 3N forces
substantially increases the energy gap between 0d5/2 and 1s1/2 levels in oxygen and between 0f7/2 and 1p3/2 levels
in calcium leading to shell closure at N=16 and N=28. Three body forces also play an important role in the
nuclear saturation properties in nuclear matter [37] ,which can be demonstrated typically in the Bruckener (G-
Matrix) theory. Thus 3N forces are likely to play an important role in the 78
Ni region as well. The poor
agreement of the1/2+
single particle states with the experimental levels is an indication of the importance of 3N
component in the interaction. Such forces, if included ,will shift the levels upwards due to increased repulsion
and are likely to improve the agreement with the experimental data.
3.2. Wave Function
Most dominant configuration of wave function for ground state and first three excited states for all the
isotones are shown in table II. It is observed that in all the isotones except in 91
Zr, the structure of the proton part
of the wave function for the ground state and first excited state 1/2+
remains the same confirming that the
excited state is due to the excitation of neutron from (d5/2) to (s1/2). In 91
Zr the structure of the proton wave
function changes indicating the more complex nature of 7/2+
and 1/2+
excitations. In 83
Ge and 87
Kr the proton
wave functions for 7/2+
state remains unchanged whereas in 85
Se, 89
Sr and 91
Zr their structure changes. The
proton wave function for 3/2+
state also remains same in all the isotones except for 91
Zr. The difference can be
attributed to the variation in proton single particle energies with changing Z.
3.3. Electromagnetic Properties
Theoretically calculated B(E2) values for the transition 1/2+
→ 5/2+
and 7/2+
→ 5/2+
are shown in table
III for each of the N=51 isotonic nuclei. The effective charges used for proton and neutron are 𝑒 𝜋
𝑒𝑓𝑓
= 1.50 and
𝑒 𝜈
𝑒𝑓𝑓
= 0.5 respectively. The calculations show that B(E2; 1/2+
→ 5/2+
) values first increase up to 87
Kr and then
decreases for 89
Sr. No experimental data is available for comparison. The decrease in B(E2;7/2+
→ 5/2+
) values
in going from midshell to 89
Sr supports the onset of shell closure at Z=40.
4. Shell Model Description of N = 51 Isotones
www.iosrjournals.org 55 | Page
IV. Conclusions
In the present work large scale shell model calculations have been performed for N = 51 isotones
nuclide 83
Ge, 85
Se, 87
Kr, 89
Sr and 91
Zr in valence space ν(0g7/2, 1d5/2, 1d3/2, 2s1/2, 0h11/2) orbitals for neutrons and
π(0f5/2, 1p3/2, 1p1/2, 0g9/2) orbitals for protons with 78
Ni core. The effective interaction is based on the
renormalization of CD-Bonn nucleon-nucleon potential developed by G - matrix theory for nuclei above 78
Ni
core. Thus simple and pure neutron configurations of (1d5/2)1ν
and (2s1/2)1ν
above the N=50 shell closure can be
assumed to describe the ground state and first excited state of all isotones. Ground state spin 5/2+
for all the
isotones is associated with the last odd neutron in d5/2 state. Similarly 1/2+
spin of first excited state can be
attributed to the excitation of the last neutron from 1d5/2 to 2s1/2 level. The increase in E(1/2+
) ̴ E(5/2+
) splitting
in going from Z=32 to 40 is direct reflection of the monopole effect wherein the energy of 1/2+
state is gradually
increasing with the filling of proton orbitals.
The calculated 1/2+
levels are consistently lower than the corresponding experimental values. The
fitting of higher 3/2+
,7/2+
and 9/2+
states with the corresponding experimental data is not good. Thus, the present
interaction in the chosen model space does not give good agreement with the experimental data. The reason for
this could be manifold.. Firstly, all these states have admixtures of coupling of single particle states with core
excitation. Secondly, it is well known that the neutron single particle orbital changes with filling of proton
number due to the attracting monopole pairing interaction between proton and neutron in spin-orbit partners
[38]. So minor adjustment in the monopole part of the neutron proton interaction and renormalization of the
single particle energies of the neutron orbitals can lead to better agreement with the experimental data. Thirdly,
recent studies have shown that 3N forces have important effect on the evolution of shell structure in neutron
rich nuclei. The three body component of these interactions gives rise to a repulsive contribution to the
monopole interaction. These forces when included can give a shift to 1/2+
states in the right direction . Lastly,
the wave functions of the 7/2+
states in Se, Kr, and Zr and 1/2+
and 3/2+
states of Zr have main components in
which proton configuration is different than the ground state configuration showing that these states are not pure
neutron excitation states.
Acknowledgements
All the calculations in the present work are carried out using computational facility of nuclear physics
group. One of authors (KM), acknowledge the financial support from UGC(India). P.C.S. acknowledges support
from Conacyt, M´exico, and by DGAPA, UNAM project IN103212
Figure 1. Calculated and experimental spectra for 83
Ge.
0
1
2
3
Energy(MeV)
5/2+
7/2+
1/2+
9/2+
7/2+
3/2+
5/2+
1/2+
3/2+
2478
8674
1046
1856
129
1486
354
Exp. jj45pna
83
Ge
5. Shell Model Description of N = 51 Isotones
www.iosrjournals.org 56 | Page
Figure 2. Calculated and experimental spectra for 85
Se.
Figure 3. Calculated and experimental spectra for 87
Kr.
Figure 4. Calculated and experimental spectra for 89
Sr.
0
1
2
3
Energy(MeV)
3/2+
9/2+
7/2+
85
Se
jj45pna
5/2+
1/2+
7/2+
3/2+ 1600
1115
462
1450
9/2+
1/2+
5/2+
539
1405
1970
268
Exp.
0
1
2
3
Energy(MeV)
5/2+
1/2+
7/2+
9/2+
3/2+
1/2+
9/2+
3/2+
7/2+
5/2+
Exp.
jj45pna
83
Kr
1550
1460
532
1420
2040
1190
649
435
0
1
2
3
Energy(MeV)
9/2+ 2108
962
748
618
2450
2061
1473
1031
1/2+
5/2+
7/2+
3/2+
3/2+
9/2+
7/2+
1/2+
5/2+
jj45pnaExp.
89
Sr
6. Shell Model Description of N = 51 Isotones
www.iosrjournals.org 57 | Page
Figure 5. Calculated and experimental spectra for 91
Zr.
Figure 6. Variation of E(1/2+) with proton no.
0
1
2
3
Energy(MeV)
5/2+
1/2+
7/2+
3/2+
9/2+
768
689
818
21299/2+
7/2+
1/2+
3/2+
5/2+
2040
2131
1882
1205
jj45pnaExp.
91
Zr
32 33 34 35 36 37 38 39 40
0.5
1
1.5
Protonno.
ex
(MeV)
Expt.
jj45pna
N=51
7. Shell Model Description of N = 51 Isotones
www.iosrjournals.org 58 | Page
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