Plenary lecture of the XIV SBPMat Meeting, given by Prof. Ichiro Takeuchi (University of Maryland, USA) on September 30, 2015, in Rio de Janeiro (Brazil).
Plenary lecture given by Prof. Hajo Freund (Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany) on September 11, 2017 in Gramado (Brazil) during the XVI B-MRS Meeting.
Plenary lecture of the XIV SBPMat Meeting, given by Prof. Nader Engheta (University of Pennsylvania) on September 28, 2015, in Rio de Janeiro (Brazil).
Plenary lecture of the XIV SBPMat Meeting, given by Prof. Ichiro Takeuchi (University of Maryland, USA) on September 30, 2015, in Rio de Janeiro (Brazil).
Plenary lecture given by Prof. Hajo Freund (Fritz-Haber-Institut der Max-Planck-Gesellschaft, Germany) on September 11, 2017 in Gramado (Brazil) during the XVI B-MRS Meeting.
Plenary lecture of the XIV SBPMat Meeting, given by Prof. Nader Engheta (University of Pennsylvania) on September 28, 2015, in Rio de Janeiro (Brazil).
Plenary lecture - XV B-MRS Meeting - Campinas, SP, Brazil - September, 25 to 29, 2016.
Author: Elvira Fortunato (CENIMAT, Universidade Nova de Lisboa, Portugal).
Research proposal on organic-inorganic halide perovskite light harvesting mat...Rajan K. Singh
Organic-Inorganic perovskite materials has many applications in the field of opto-electronics such as photo-voltaic cells, LEDs, sensors, memory devices etc. due to its excellent optical and electrical properties. Presence of Pb in such type of perovskite is the biggest challenge for researchers.
Progress in all inorganic perovskite solar cellMd Ataul Mamun
Since their first introduction in the research arena, the hybrid organic-inorganic perovskite photovoltaic cells have been showing frequent record breaking power conversion efficiencies (PCEs). Despite the rapid increase in PCE by engaging new perovskite materials as active layers as well as new fabrication techniques, their stability remains too poor to go for a mass production. Mainly the organic materials in the hybrid PSCs are responsible for this instability. Consequently, very recently, different approaches are taken to replace these organic components by inorganic ones to fabricate all-inorganic PSCs. Though these first-generation all-inorganic PSCs are yet to produce competitive PCEs like their counterparts, they have already demonstrated superb stability to be a propitious bidder for solar cell energy yielding. The state-of-the-art quantum dots based cells shown efficiency as high as 10.77% and intact stability for months.
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.
Study of columnar growth polycrystalline (sn, cr) co doped in2 o3 films depos...EROMOR
In this work, (Sn, Cr) co-doped In2O3 polycrystalline films were grown at room temperature by sputtering method using a base pressure of ∼5×10−2mbar (a low vacuum condition) in order to improve the oxidation process and reduce the time of films production.
A NOVEL PRECURSOR IN PREPARATION AND CHARACTERIZATION OF NICKEL OXIDE (NIO) A...antjjournal
Synthesis of Nickel Oxide (NiO) nanoparticles and cobalt oxide (CO3O4) materials synthesis by aqueous chemical growth (ACG) Techniques. Oxide based material having a wide band gap, and suitable for optical devices,Optoelectronic devices, UV photodetector, and Light emitting diode LEDs. The analysis
and characterizationof Nickel Oxide (NiO) and cobalt oxide (CO3O4) nanoparticles by(1) X-ray diffraction (XRD), (2) Scanning electron microscopy (SEM), and (3) Ultraviolet–visible (UV–Vis) spectroscopy.
Probing Molecular Electronic Structure Using High Harmonic Generation TomographyChelsey Crosse
The structure of valence electronic orbitals of a molecule determines the majority of chemical properties. Generation of high-order harmonic frequencies from atomic sources has been directly related to the electronic structure of the atom, (1) and extended as far as tomographic reconstruction of linearly symmetric polyatomic molecular systems with some success. (2,3,4)
However, because of the increased resolution of these reconstructions, discrimination of fine details of the orbital reconstructions reveals some inconsistencies in the orbital shapes when compared with past models & theoretical calculations. (2) There are several proposed corrections to the Strong Field Approximation (SFA) that currently underlies tomographic reconstruction as well as all other experiments that use high harmonic generation (HHG) to probe molecular systems. (5,6,7)
---------------------------------------------------------------------
1. Lewenstein et al. Phys Rev A 49 (3) 1994.
2. Salieres, Maquet, Haessler, Caillat, Taieb. Rep. Prog. Phys. 75 (2012) 062401.
3. Li, Liu, Yang, Song, Zhao, Lu, Li, Xu. Opt. Ex. 21 (6) 2013. 7599.
4. Torres et al. Phys Rev. Lett. 98 (2007) 203007.
5. Diveki et. al. J. Chem Phys. 414 (2013) 121.
6. Yip, Palacios, Rescigno, McCurdy, Martin. J. Chem Phys 414 (2013) 112.
7. Spanner, Patchkovskii. J. Chem. Phys. 414 (2013) 10.
Plenary lecture - XV B-MRS Meeting - Campinas, SP, Brazil - September, 25 to 29, 2016.
Author: Elvira Fortunato (CENIMAT, Universidade Nova de Lisboa, Portugal).
Research proposal on organic-inorganic halide perovskite light harvesting mat...Rajan K. Singh
Organic-Inorganic perovskite materials has many applications in the field of opto-electronics such as photo-voltaic cells, LEDs, sensors, memory devices etc. due to its excellent optical and electrical properties. Presence of Pb in such type of perovskite is the biggest challenge for researchers.
Progress in all inorganic perovskite solar cellMd Ataul Mamun
Since their first introduction in the research arena, the hybrid organic-inorganic perovskite photovoltaic cells have been showing frequent record breaking power conversion efficiencies (PCEs). Despite the rapid increase in PCE by engaging new perovskite materials as active layers as well as new fabrication techniques, their stability remains too poor to go for a mass production. Mainly the organic materials in the hybrid PSCs are responsible for this instability. Consequently, very recently, different approaches are taken to replace these organic components by inorganic ones to fabricate all-inorganic PSCs. Though these first-generation all-inorganic PSCs are yet to produce competitive PCEs like their counterparts, they have already demonstrated superb stability to be a propitious bidder for solar cell energy yielding. The state-of-the-art quantum dots based cells shown efficiency as high as 10.77% and intact stability for months.
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.
Study of columnar growth polycrystalline (sn, cr) co doped in2 o3 films depos...EROMOR
In this work, (Sn, Cr) co-doped In2O3 polycrystalline films were grown at room temperature by sputtering method using a base pressure of ∼5×10−2mbar (a low vacuum condition) in order to improve the oxidation process and reduce the time of films production.
A NOVEL PRECURSOR IN PREPARATION AND CHARACTERIZATION OF NICKEL OXIDE (NIO) A...antjjournal
Synthesis of Nickel Oxide (NiO) nanoparticles and cobalt oxide (CO3O4) materials synthesis by aqueous chemical growth (ACG) Techniques. Oxide based material having a wide band gap, and suitable for optical devices,Optoelectronic devices, UV photodetector, and Light emitting diode LEDs. The analysis
and characterizationof Nickel Oxide (NiO) and cobalt oxide (CO3O4) nanoparticles by(1) X-ray diffraction (XRD), (2) Scanning electron microscopy (SEM), and (3) Ultraviolet–visible (UV–Vis) spectroscopy.
Probing Molecular Electronic Structure Using High Harmonic Generation TomographyChelsey Crosse
The structure of valence electronic orbitals of a molecule determines the majority of chemical properties. Generation of high-order harmonic frequencies from atomic sources has been directly related to the electronic structure of the atom, (1) and extended as far as tomographic reconstruction of linearly symmetric polyatomic molecular systems with some success. (2,3,4)
However, because of the increased resolution of these reconstructions, discrimination of fine details of the orbital reconstructions reveals some inconsistencies in the orbital shapes when compared with past models & theoretical calculations. (2) There are several proposed corrections to the Strong Field Approximation (SFA) that currently underlies tomographic reconstruction as well as all other experiments that use high harmonic generation (HHG) to probe molecular systems. (5,6,7)
---------------------------------------------------------------------
1. Lewenstein et al. Phys Rev A 49 (3) 1994.
2. Salieres, Maquet, Haessler, Caillat, Taieb. Rep. Prog. Phys. 75 (2012) 062401.
3. Li, Liu, Yang, Song, Zhao, Lu, Li, Xu. Opt. Ex. 21 (6) 2013. 7599.
4. Torres et al. Phys Rev. Lett. 98 (2007) 203007.
5. Diveki et. al. J. Chem Phys. 414 (2013) 121.
6. Yip, Palacios, Rescigno, McCurdy, Martin. J. Chem Phys 414 (2013) 112.
7. Spanner, Patchkovskii. J. Chem. Phys. 414 (2013) 10.
AUR 2013 Опыт внедрения технологии пространственного проектирования Sergei Penkov
Autodesk Universiy Russia 2013
Опыт внедрения технологии пространственного проектирования в
ОАО «ВНИПИгаздобыча»
Дмитрий Клюев, Илья Овчинников, Сергей Пеньков
Microstructural and Dielectric Characterization of Sr doped Ba(Fe0.5Ta0.5)O3 ...theijes
Solid state reaction method was used to synthesize Ba1-xSrx(Fe0.5Ta0.5)O3 ceramic(x=0, 0.1, 0.2, 0.3, 0.4 and 0.5). The raw materials of making Sr doped Ba(Fe0.5Ta0.5)O3 were BaCO3, SrCO3, Fe2O3, Ta2O5 (purity better than 99%). Pellet and ring shaped samples prepared from each composition were sintered at 1400 and 1450ºC for 5 hour. The phase formation of Ba1-xSrx(Fe0.5Ta0.5)O3 was checked using X-ray diffraction (XRD) technique and observed a cubic perovskite crystal structure in space group Pm3m (221). Microstructure of the individual compound was examined by the field emission scanning electron micrograph (FESEM). Grain size was found to be varied with Sr content. The lattice parameter decreased with increasing Sr content. Dielectric spectroscopy was applied to investigate the electrical properties of BSFT at room temperature and in a frequency range of 100Hz–100 MHz. An analysis of the dielectric constant εʹ and loss tangent tan with frequency was performed assuming a distribution of relaxation times. The low frequency dielectric dispersion corresponds to the DC electrical conductivity.
The public trial lecture presented by Mohammadreza Nematollahi on 8th of October 2014 at Norwegian University of Science and Technology. The theoretical models and the experimental progress of highly mismatched alloys, as well as their optoelectronic applications are covered.
Trabalho apresentado pelo professor Carlos A. Figueroa, pesquisador do Instituto na UCS, no evento PBII&D 2009, em São José dos Campos, em 10 de setembro de 2009.
How Carbon Nanotubes Collapse on Different Ag Surface?ijrap
The collapse and stability of carbon nanotubes (CNTs) on noble metal silver different surfaces were studied
using molecular mechanics and molecular dynamics simulations. From the results, it can be seen that the
CNTs can collapse spontaneously onto different silver surface [(1 0 0), (1 1 0), (1 1 1)] due to the van der
Waals force between them. Furthermore, the CNT collapsing on (1 0 0) and (1 1 1) surface are much easier
than that on (1 1 0) surface. Moreover, the results show that the collapsed CNTs exhibit as linked graphene
ribbons and have the largest area to contact with the Ag surface, which greatly enhances adhesion between
the CNTs and the Ag surface and keeps the system much more stable.
How Carbon Nanotubes Collapse on Different Ag Surface? ijrap
The collapse and stability of carbon nanotubes (CNTs) on noble metal silver different surfaces were studied
using molecular mechanics and molecular dynamics simulations. From the results, it can be seen that the
CNTs can collapse spontaneously onto different silver surface [(1 0 0), (1 1 0), (1 1 1)] due to the van der
Waals force between them. Furthermore, the CNT collapsing on (1 0 0) and (1 1 1) surface are much easier
than that on (1 1 0) surface. Moreover, the results show that the collapsed CNTs exhibit as linked graphene
ribbons and have the largest area to contact with the Ag surface, which greatly enhances adhesion between
the CNTs and the Ag surface and keeps the system much more stable.
Plenary lecture of the XVIII B-MRS Meeting given by Prof. Alan Taub (University of Michigan, USA) on September 26, 2019 at Balneário Camboriú (Brazil).
Plenary lecture of the XVIII B-MRS Meeting given by Prof. Antonio José Roque da Silva (CNPEM, Brazil) on September 24, 2019 at Balneário Camboriú (Brazil).
Tribute in honor of Prof. Ivo Alexander Hümmelgen, a member of the Brazilian materials research community, who died unexpectedly in March 2019. The tribute was made by Prof. Marco Cremona (PUC-Rio), on September 23, 2019 in Balneário Camboriú (Brazil), at the opening of symposium F, that was dedicated to Organic Electronics, the research area of Prof. Hümmelgen.
Memorial Lecture Joaquim da Costa Ribeiro, given by Prof. Yvonne P. Mascarenhas (IFSC and IEA/ USP, Brazil) in the Opening Ceremony of the XVIII B-MRS Meeting on September 22, 2019 at Balneário Camboriú (Brazil).
Presentation of the XVIII B-MRS Meeting (September 22 - 26, 2019, Balneario Camboriú), given by Prof. Ivan H. Bechtold, chair of the event, at the closing ceremony of the XVII B-MRS Meeting, on September 20, 2018.
Memorial lecture "Joaquim da Costa Ribeiro" given by Prof. João A. H. da Jornada (IF-UFRGS) on September 10, 2017 in Gramado (Brazil) during the opening of the XVI B-MRS Meeting.
Plenary lecture given by Prof. Kenneth Gonsalves (ITT Mandi, India) on September 12, 2017 in Gramado (Brazil) during the XVI B-MRS Meeting. Acknowledgment: ITT Mandi.
More from Sociedade Brasileira de Pesquisa em Materiais (20)
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
In silico drugs analogue design: novobiocin analogues.pptx
Role of Atomic-Scale Modeling in Materials Design Discovery.
1. Role of Atomic-Scale Modeling in
Materials Design Discovery
Susan B. Sinnott
Department of Materials Science and Engineering
Penn State University
University Park, PA
XV Brazil MRS Meeting
September 27, 2016
2. Materials State Awareness with Atomic and
Nanometer Scale Computational Methods
• Electronic-structure level
• High fidelity methods available:
• Quantum chemical approaches
• Density functional theory (DFT)
• Off-the-shelf codes widely available
• Wide-spread understanding of strengths and limitations
Atomic-scale level
Many-body, realistic potentials have been available for over 30 years
Ideal for examining systems under extreme environments
Necessary to investigate chemistry + microstructure + mechanics +
mechanisms + …..
Physics-based model development
Inform microscale and mesoscale models
Explain experimental observations (strong “suggestion about
what the atoms are doing”)
3. MAX Phases
10/4/2016
9 M elements
× 12 A elements
× 2 X elements
× 3 values of n
648 MAX phases
50/50 solid solutions also
possible for M, A, and X
31,590 MAX phases
(10,530 M2AX phases)
Example 1: Material by Design
5. Stability trends among M2AX phases
5
Valence mismatch
Radius mismatch
Electronegativity mismatch
Total ionicity
Total # of valence electrons
% of M2AX phases that are stable vs…
6. Magnetic M2AX Phases
Cr2InN & Cr4(CdIn)N2 show ferromagnetic ordering at 0K
10/4/2016 6
Cr2InN Cr4(CdIn)N
Formation
energy
(meV/atom)
7 21
Magnetization
energy (meV/Cr
atom)
68 70
Final magnetic
moment
(μB/Cr atom)
1.08 1.18
8. 2D Material Formation Energies
10/4/2016 8
Ex.) Ef(Ti2CO2) = E(Ti2CO2) - E(TiC) – E(TiO2)
2D materials will never be “stable” compared to 3D
competing phases, but with a low enough
metastability they can be stabilized kinetically.
9. Comparing O, F, & OH Binding Energies
9
Eb = E Mn+1XnTm – E Mn+1Xn –
m
2
E T2 – mμT
Coated MXene
Bare MXene
Surface species reference
Surface species chemical potential
μO = ΔG
f
H2O
− 2μH
μOH = ΔG
f
H2O
−μH
μF = ΔGf
HF− μH
All depend on μH
Ashton, et al. Journal of Physical Chemistry C (2016)
10. Comparing O, F, & OH Binding Energies
10
Ti2C Sc2C
For all transition metals other than Sc, O binding is
preferred for all 𝜇 𝐻.
Ashton, et al. Journal of Physical Chemistry C (2016)
11. MXene Formation Energies
10/4/2016 11
V2CO2 has the highest
formation energy of all
MXenes that have been
synthesized to date.
All MXenes below
V2CO2 (within the
yellow threshold) should
be creatable from a
thermodynamic
perspective.
16. Example 2: Nickel-Based Superalloy Design
BRI: Searching for RE Alternative
through Crystal Engineering
• Used in high temperature-
applications such as gas-turbines1
• Two phases present:
γ- Ni matrix
γ’- Ni3Al (~ 70% volume)
Microstructure of γ-γ’ phases of Ni
single crystal superalloys2
L12 – Al at
corners, Ni at
face-centers
1. R Schafrik and R Sprague; Adv. Mat. and Proc. 162 (2004)
2. P Caron and O Lavigne; J. Aerospace Lab. 3 (2011)
Objective: Identify alternative, earth-
abundant alternatives to rare earth
metals in Ni-based superalloys
17. BRI: Searching for RE Alternative
through Crystal Engineering
Defect Formation Energy
Defect formation energy of incorporating dopant X is defined as:
Etot[Xq] = total energy of the system with the defect
Etot[bulk] = total energy of the system without the defect
n = number of atoms added (n > 0) or removed (n < 0)
μi = chemical potential of species i
X Ef (XAl) (eV) Ef (XNi) (eV)
B 2.60 0.87
Cr 1.40 (1.351) 0.93 (0.921)
Ce 0.81 1.81
Zr 0.10 (0.041) 0.31 (0.201)
1. D E Kim, S L Shang, Z K Liu; Intermetallics 18 (2010)
18. BRI: Searching for RE Alternative
through Crystal Engineering
DFT-Materials Informatics-Experiment
• Defect formation energy
CrAl > CrNi
• From the principle component
analysis (PCA) plot, materials
informatics (by Krishna Rajan)
concludes that Cr prefers Al site
without DFT calculation results.
Experimental validation
from Jim LeBeau:
Cr EDS map corresponds
with the Al EDS map
19. Chemical design vector: mapping a ‘periodic table’ for alloys
Grant # FA9550-12-1-0456
Reporting period: Jan.2013-May 2014
Sims, Stoloff and
Hagel (1986) /
Pollak and Tin
(2006)
• New guide for seeking
similarity of elements
with respect to
influence of alloy
properties
• Captures information
not possible from
periodic table
mapping of elements
Informatics work
of Krishna Rajan
20. Materials State Awareness with Atomic and
Nanometer Scale Computational Methods
• Electronic-structure level
• High fidelity methods available:
• Quantum chemical approaches
• Density functional theory (DFT)
• Off-the-shelf codes widely available
• Wide-spread understanding of strengths and limitations
• Atomic-scale level
• Many-body, realistic potentials have been available for over 30 years
• Ideal for examining systems under extreme environments
• Necessary to investigate chemistry + microstructure + mechanics +
mechanisms + …..
• Physics-based model development
• Inform microscale and mesoscale models
• Explain experimental observations (strong “suggestion about
what the atoms are doing”)
21. 30 Years of Many-Body Atomic-Scale
Potentials (Reactive Force Fields)
May 2012 issue
Historically developed for materials
with specific types of chemical bonds
Tersoff potentials for Si
Brenner or REBO potential for C,H
+ O,F,S,….
AIREBO
EAM potentials for metals
MEAM for metals and oxides
EAM+ES for metals and oxides
Rigid ion (Buckingham) potentials for
ionically bound materials
Used to examine phenomena at the
atomic and nanometer scale and
develop a qualitative, mechanistic
understanding
22. Metallic
IonicCovalent Bone/biocomposites
Aqueous biological systems
Interconnects
Corrosion/Oxidation
Thermal barrier coatings
Catalysts
Multicomponent Systems
• Inherent to many
applications
• Challenging for:
• First-principles electronic
structure methods (large
systems, lacking usual
symmetry)
• Atomic-scale methods
because of their
heterogeneous nature
• This need spurred the
development of next
generation potentials
(COMB, ReaxFF, and
others)
S.R. Phillpot and
S.B. Sinnott,
Science (2009)
23. Example 3: Cu (001)/a-SiO2 Interfaces
Structural properties of the interface
Oxidation of Cu is limited to the first two Cu layers; formation of Cu2O
Type of interface
W (J/m2) Cu-O
(%)Exp COMB
Cu/a-SiO2 + 0 VO
0.5 - 1.2 a
0.6 - 1.4 b
1.810 22
Cu/a-SiO2 + 10 VO 0.629 13
Cu/a-SiO2 + 20 VO 0.289 11
a Oh, et al., J. Am. Ceram. Soc. (1987)
b Pang and Baker, J. Mater. Res. (2005)
• Cu-O bonds play crucial roles in adhesion
of the interface
• Adhesion of Cu/dielectric layer decreases
with O defects
Introduced O vacancies at the interface
0, 10 and 20 VO
24. Charge Transfer Across the Interface
DFT: Nagao et al., COMB: Shan et al.
-10 0 10
-0.020
-0.015
-0.010
-0.005
0.000
0.005
0.010
0.015
0.020
<n(D)>(A
-3
)
Distance (angstrom)
COMB
25. BRI: Searching for RE Alternative
through Crystal Engineering
Example 4: Deformation of metals - Ni
dislocations within grains are generated and
evolve over time
grain are in the BCC arrangement
Common
neighbor analysis
Polycrystalline Ni after being
subjected to tensile test with
constant strain rate (=4x10-9 s-1)
1. A. Kumar, T. Liang, A. Chernatynskiy, Z. Lu, M. Noordhoek, K. Choudhary, S.R. Phillpot, S.B. Sinnott; J. Phys.:
Condensed Matter (in preparation)
2. Y. Mishin, D. Farkas, M.J. Mehl, D.A. Papaconstantopoulos; Phys. Rev. B 59 (1999)
Stacking fault energies:
<112> and <101>
COMB Ni potential1 EAM Ni potential2
Stacking fault energy of Ni1
compared with EAM2 potential
Centro-symmetry analysis
26. BRI: Searching for RE Alternative
through Crystal Engineering
Al deformation predicted by different potentials
COMB Al potential1
EAM Al potential2 Stacking fault energies:
<112> and <101>
Stacking fault energy of Al1
compared with EAM2 potential
1. A. Kumar, T. Liang, A. Chernatynskiy, Z. Lu, M. Noordhoek, K. Choudhary, S.R. Phillpot, S.B. Sinnott; J. Phys.:
Condensed Matter (in preparation)
2. Y. Mishin, D. Farkas, M.J. Mehl, D.A. Papaconstantopoulos; Phys. Rev. B 59 (1999)
Potential energy surface
illustrating the <112> barrier
to be less than the <101>
barrier1
27. BRI: Searching for RE Alternative
through Crystal Engineering
Mechanical deformation of Ni3Al at the g/g’ interface
1. A. Kumar, T. Liang, A. Chernatynskiy, Z. Lu, M. Noordhoek, K. Choudhary, S. R. Phillpot, S.B. Sinnott (in
preparation)
2. M.H. Yoo, M.S. Daw, M.I. Baskes, V. Vitek, D.J. Srolovitz, Eds.; New York: Plenum Press; 1989. p. 401.
Thermostat
Active
Rigid moving
Rigid moving
Thermostat
Active
Ni3Al
Ni
τzx
Z
[010]
X
[101]
Y
[10 -1]
τzx
• Edge dislocations at the Ni-Ni3Al interface
• Predict mechanisms associated with
applied shear stress and dislocation
motion
Ni3Al Ec
(eV/atom)
B
(GPa)
G
(GPa)
COMB1 -4.61 198 93
exp.2 -4.62 195 96
Simulation box size:
16.67x16.67x9.21 nm3
Total number of
atoms: 179,600
Dislocation
28. Technical Fundamental Barriers
• Parameterization of transferrable, next-generation potentials is non-
trivial. For some historical potentials, numerous parameterizations exist.
The general equation for COMB is:
.
• Validation of predicted trends and quantification of error bars.
• Comfort within the broader community of how and when potentials work
well and when the transferability of parameterized properties breaks
down. The materials community is familiar with strengths and limitations
of electronic structure calculations and continuum level (e.g., finite-
element level modeling). Non-experts are less comfortable with atomic-
scale methods.
• Dissemination is straightforward, maintenance is challenging!
i
ij
vdW
ji
polar
ij
jikijiiijiijiji
S
iT rEriqErCqBqqrVqEE )(),(),()(,,
2
1
)(
30. Challenges and needs that will shape future directions
• Big-picture challenges:
• What is the role of theory/computational modeling in the design,
processing, and application of materials?
• How do we integrate the latest computational approaches with
experimental data to improve predictability?
• To what extent are computational methodologies available that are
applicable to the physics of interest in actual systems (materials, length and
time scales)?
• How do we ensure the next generation of scientists and engineers can work
in this new paradigm?
• What is needed:
• Natural workflow from discovery codes to predictive software
• Tight integration between processing, characterization, and computational
approaches
• Accurate error bars for the results of theoretical/computational method
results
• Widespread dissemination of software with robust documentation