This PPT gives introduction
to Dielectrics, Piezoelectrics & Ferroelectrics Materials, Methods and Applications. A quick glance at the dielectric phenomena, symmetry, classification, modelling, figures of merit and applications.
Comprehensive overview of the physics and applications of
ferroelectric
Magnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materials
weiss molecular theory of ferromagnetismsantoshkhute
Weiss' Theory (Domain theory of ferromag : According to weiss, a feromagnetic substance. contains atoms with permanent magnetic. moments, as in a paramagnetic substance, but due to special form of interaction.
Magnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materialsMagnetic properties of materials
weiss molecular theory of ferromagnetismsantoshkhute
Weiss' Theory (Domain theory of ferromag : According to weiss, a feromagnetic substance. contains atoms with permanent magnetic. moments, as in a paramagnetic substance, but due to special form of interaction.
This Presentation "Energy band theory of solids" will help you to Clarify your doubts and Enrich your Knowledge. Kindly use this presentation as a Reference and utilize this presentation
Dielectric and Magnetic Properties of materials,Polarizability,Dielectic loss...A K Mishra
In this PPT contains ,Dia,Para,Ferromagnetism,Clausius-Mossoti equation,Dielectric Loss ,Hysteresis,Hysteresis loss and its Applications,Determination of susceptibility,types of polarisation in mateials,relative permability
This Presentation "Energy band theory of solids" will help you to Clarify your doubts and Enrich your Knowledge. Kindly use this presentation as a Reference and utilize this presentation
Dielectric and Magnetic Properties of materials,Polarizability,Dielectic loss...A K Mishra
In this PPT contains ,Dia,Para,Ferromagnetism,Clausius-Mossoti equation,Dielectric Loss ,Hysteresis,Hysteresis loss and its Applications,Determination of susceptibility,types of polarisation in mateials,relative permability
HBA Microwave by Dr Sir Rabnawaz of DMME department of PIEAS universityMaqsoodAhmadKhan5
HBA Microwave by Dr Sir Rabnawaz of DMME department of PIEAS university. This presentation include the detailed operational and functional working of microwave oven.
Presentation on thermionic converter for direct energy conversionRAJBALA PURNIMA PRIYA
Thermionic conversion is also recently revisited for concentrated solar power applications.
Formulation of new concepts such as thermionic–photovoltaic and thermionic–thermoelectric combined hybrid devices are recent applications.
Nuclear thermionic power system are used for space applications.
Thermionic converters are also used for cooling of electronics devices.
Simulation of Induction heater using IRFZ44N MOSFETanjeana
This PPT contains the Schematic circuit model and simulated output of Induction heater using IRFZ44N MOSFET along with the working principle and block diagram.
Electrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materialsElectrical properties of materials
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
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 .
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
2. Outline
• Dielectrics and dielectric polarization
• Dielectrics -> Piezoelectrics -> Pyroelectrics -> Ferroelectrics
• Ferroelectric phenomena and properties
• Measurement of spontaneous polarization
• Classification of ferroelectrics
• Application of ferroelectrics
3. Dielectrics
Dielectric is an electrical insulator which can be
polarized on application of external electric filed.
They do not conduct electricity due to the very low density
of free charge carriers. Here, the electrons are bound to
microscopic regions within the material, that is the atoms,
molecules, or clusters.
D 0 E P 0 E 0 E 0 (1 )E 0 E
Polarization is defined as dipole moment per unit volume. It
modifies dielectric function of a vacuum, for example to
increase the capacity (i.e. the ability to store charge) of
capacitors.
1. Electronic Polarizability
2. Ionic Polarizability
3. Dipolar Polarizability
4. Space Charge Polarizability
5. Polarization is the separation of a positive and a negative
charge barycenter of bound charges. If this separation is
induced by an applied electric field, it is called dielectric
polarization.
If the separation is induced by an applied strain field, it is
called piezoelectric polarization.
Several dielectric crystals exhibit a spontaneous
polarization below a critical temperature which is related
to a change in crystal symmetry.
A spontaneous polarization in the material leads to
pyroelectric effects under temperature changes.
Ferroelectricity is obtained when the orientation of
polarization can be reoriented between
crystallographically equivalent configurations by an
external field.
Piezoelectrics, Pyroelectrics & Ferroelectrics
6. Ferroelectric Materials: A ferroelectric material is a material
that exhibits, over some range of temperature, a
spontaneous electric polarization that can be reversed or
reoriented by application of an electric field
Ferroelectricity
Domain is a region in which all the individual dipoles
point in a particular direction
Barium titanate is a prototype perovskite
ferroelectric
Perovskite general formula: ABO3
In barium titanate Ba2+ occupies A site (corner
of cube)O2-occupies face centre and Ti4+
occupies body centre
Dipole moment of a unit cell arises from Ti4+ off-
centering
9. Temperature dependence of the spontaneous polarization and permittivity in a ferroelectric
material. (a)–(f) indicate the temperature ranges for each application.
Temperature dependence of electrical properties of a ferroelectric
Night vision
10. Ferroelectricity: Two main classes of ferroelectrics
Ex: NaNO2 ,KDP
Ex: ionic crystals with perovskite,
or ilmenite structure.
Based on the origin of
spontaneous Polarization
11. Ferroelectric Materials can be structurally categorized into 4 groups:
1. Corner Sharing Octahedra:
1. Perovskite-Type Compounds
(such as BaTiO3, PT, PZT, PMN, and PLZT)
2. Tungsten-Bronze-Type Compounds (such
as PbNb2O6)
3. Bismuth Oxide Layer Structured Compounds (such
as Bi4Ti3O12 andPbBi2Nb2O9)
4. Lithium Niobate and Tantalate (such as LiNbO3 andLiTaO3)
2. Compounds Containing Hydrogen Bonded Radicals (such as
KDP, TGS, and Rochelle Salt)
3. Organic Polymers (such as PVDF and co-polymers)
4. Ceramic Polymer Composites (such as PZT-PE)
Types of Ferroelectric Materials
Perovskite (BaTiO3) LiNbO3
Polyvinylidene fluoride (PVDF)
12. Ferroelectric properties
Most ferroelectric materials undergo a structural phase transition from a high-temperature nonferroelectric
(or paraelectric) phase into a low-temperature ferroelectric phase.
The symmetry of the ferroelectric phase is always lower than the symmetry of the paraelectric phase.
The temperature of the phase transition is called the Curie point, TC.
Above the Curie point the dielectric permittivity falls off with temperature
according to the Curie–Weiss law
where C is the Curie constant, T0 (T0 ≤TC) is the Curie–Weiss temperature
Some ferroelectrics, such as BaTiO3, undergo several phase transitions
into successive ferroelectric phases.
13. Ferroelectrics have very high dielectric constants at
relatively low applied field frequencies. Capacitors
made from these materials can be significantly
smaller than capacitors made out of other
dielectric materials.
The combined properties of memory,
piezoelectricity, and pyroelectricity make
ferroelectric capacitors some of the most useful
technological devices in modern society.
Ferroelectric capacitors are at the heart of medical
ultrasound machines, high quality infrared cameras,
fire sensors, sonar, vibration sensors, and even fuel
injectors on diesel engines.
Hysteresis means memory and ferroelectric
capacitors are used to make ferroelectric RAM for
computers and RFID cards.
The electro-optic modulators that form the
backbone of the Internet are made with
ferroelectric materials.
Applications of Ferroelectrics
14. Ferroelectricity: Landau-Ginzburg phenomenological theory
Free energy Order parameter (polarization) Electric field
F
1
aP2
1
bP4
1
cP6
... EP
2 4 6
To find the equilibrium solution we need to find the
minima of FP by solving the equation:
Ignoring higher terms we can get the linear solution:
F
0
P
F
aP E 0
P
P
1
E a
All the coefficients of polarization have temperature
dependence. The dependence of a on temperature can
be approximated as: a =
𝑻−𝑻𝒄
𝑪
Х =
𝑪
𝑻−𝑻𝒄
Curie Weiss Law