This document discusses different types of solids and their properties. There are two main types of solids - crystalline solids and amorphous solids. Crystalline solids have a regular repeating pattern of atoms and melt at a fixed temperature, while amorphous solids have irregular atomic arrangements and melt over a range of temperatures. Properties like cleavage, heat of fusion, and anisotropy also differ between the two types of solids. Methods for analyzing crystal structures using X-ray diffraction like Bragg's equation and the rotating crystal method are also summarized.
Contains information about various crystal types in solid state chemistry like Rock Salt, Wurtzite, Nickel Arsenide, Zinc Blende etc. It also gives a brief description of lattice energy and Born Haber cycle.
Contains information about various crystal types in solid state chemistry like Rock Salt, Wurtzite, Nickel Arsenide, Zinc Blende etc. It also gives a brief description of lattice energy and Born Haber cycle.
X ray, invisible, highly penetrating electromagnetic radiation of much shorter wavelength (higher frequency) than visible light. The wavelength range for X rays is from about 10-8 m to about 10-11 m, the corresponding frequency range is from about 3 × 1016 Hz to about 3 × 1019 Hz.
Crystal Structures and X-Ray Diffraction - Sultan LeMarcslemarc
Report on the investigation of the characteristics of X-rays by measuring the count rate of X-rays reflected off alkali halide crystals at varying angles of incidence and using the principles of Bragg’s law. The experiment probes into crystal structures using X-ray diffractometry and deduces the lattice constants and ionic radii using the Miller index notation. The experiment successfully computes the characteristic wavelengths of Copper and clearly demonstrates the effect of filters on spectrum intensities. The interpretation of Miller indices and diffraction patterns are effectively used to analyse crystalline structures and compare lattice arrangements. By Sultan LeMarc
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
Personal development courses are widely available today, with each one promising life-changing outcomes. Tim Han’s Life Mastery Achievers (LMA) Course has drawn a lot of interest. In addition to offering my frank assessment of Success Insider’s LMA Course, this piece examines the course’s effects via a variety of Tim Han LMA course reviews and Success Insider comments.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
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An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
3. 3 Characteristic Crystalline Solids Amorphous Solids
Melting point Melt at fixed temperature
Melt steadily over range of
temperatures
Arrangements of
constituent particles
regular Irregular
Shape Regular and definite shape Irregular shape in nature
Cleavage
When cut, two smooth and
plain pieces are obtained
When cut, two surfaces of
irregular shape is obtained
Heat of fusion definite Indefinite
Anisotropy Anisotropic Isotropic
Nature True solids Pseudo solids
4. Solid state
1. In a solid, the particles (atoms, molecules or ions) are closely packed
together.
2. The forces between the particles are strong so that the particles cannot eely
but can only vibrate.
3. Thus a solid has a stable, definite shape and a definite volume. Their shape
can be changed only by application of force.
TYPES OF SOLIDS:
1. Following are the different types of solids:
Crystalline solids : It exists as small crystals, each crystal having a
characteristic geometrical shape, in a crystal, the atoms, molecules or ions. are
arranged in a regular repeating three dimensional pattern called the crystal
lattice.
4
6. Solid state
Amorphous solids :
It has atoms, molecules or ions arranged at random and lacks the ordered
crystalline lattice.
In their disordered structure, amorphous solids resemble liquids.
Crystalline substances are said to be anisotropic (i.e. the magnitude of
physical property varies with directions) whereas amorphous solids are said
to be isotropic (i.e. the magnitude of physical property remains the same in
all directions).
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7. Solid state
Depending upon the nature of forces acting the solids can be divided into four
types:
(i) Covalent Solids: In these solids the constituent units are attached by
covalent linkages. Depending on arrangement, these can be divided into
isotropic and anisotropic substances.
Isotropic Substances:
These systems show uniform velocity of light in all directions.
Amorphous substance exhibit this property.
Other parameters like refractive index, thermal and electrical conductivities are
also uniform in all directions.
Eg : Water, glass
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8. Solid state
Anisotropic Substances:
The velocity of light is not uniform in all directions.
When a ray enters anisotropic substance it splits up into two separate
components which travel with different velocities.
The other physical properties which are mentioned in isotropic substance also
vary in anisotropic substances.
Eg: Silver iodide.
8
9. PROPERTIES OF Crystals:
Crystal habit: The external shape of the crystal is called as the crystal habit.
The plane surfaces of the crystal are called faces and angles between the faces
are called interfacial angles. The interfacial angles for a given crystalline
substance are always the same.
Crystal symmetry: This is an important property of crystals. There are three
types of symmetry elements associated with a crystal. These are called
elements of symmetry.
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10. PROPERTIES OF Crystals:
Plane of symmetry: A crystal is said to have plane of symmetry if it can be
divided by an imaginary line into equal parts, each of which is exact mirror
image of the other.
Axis of symmetry: It is an imaginary line drawn through the crystal such
that during rotation of crystal through 360°,the crystal looks the same more
than once.
Centre of symmetry : It is a point at the centre of the crystal so that any
line drawn through it will meet the surface or the crystal at equal distance
on either side.
10
11. PROPERTIES OF Crystals:
Crystal structure: The particles (atoms, molecules or ions) in crystals are
highly ordered and they are arranged in a regular pattern that extend in all
directions. The overall arrangement of particles in a crystal is called the crystal
lattice, space lattice or lattice.
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15. Methods of crystal analysis
When a beam of X-rays is allowed to pass through crystal lattice, a large
number of images of different intensities are formed.
A crystal lattice is considered to be made up of regular planes which are
separated by equal distance.
Since the wavelength of X-ray is comparable to the interatomic distances,
Laue suggested that crystal can act as grating to X-rays.
So, if the diffracted waves are in the same phase, they reinforce each other
and a series of bright spots are produced on a photographic plate placed in
their path as shown in Fig.
15
16. Methods of crystal analysis
On the other hand, if the diffracted waves are out of phase, interference will
result, and dark spots are caused on the photographic plate.
From the overall diffraction patterns produced by a crystal, we can get the
detailed information regarding the position of particles in the crystal.
16
17. Bragg's equation
In 1913 W.L. Bragg made a successful attempt in determining the
interatomic distance in a crystal lattice using X-rays. The study of crystal
structure with the help of X-rays is called X-ray crystallography.
He showed that:
X-rays obey laws of reflection
The extra distance travelled by the second ray [P] is an integral number of
wavelength
𝒏𝝀 = 𝟐𝒅 𝒔𝒊𝒏𝜽
17
18. Bragg's equation
𝑛λ=2𝑑 𝑠𝑖𝑛𝜃
For a given set of lattice planes d and A are fixed.
d - distance between
λ - wavelength of x-rays
θ - Angle at which the X-rays strike the crystal
n - order of reflection.
18
19. Deviation of Bragg's equation
As shown in figure a beam of X-ray is following on the crystal surface.
The 2 successive planes of crystal separated by distance, d.
Let X-ray of wavelength λ strike the force first plane at an angle θ same rays
are reflected at the same plane. And some will penetrate and get reflected
from the second plane.
These rays will be in force with those reflected from first plane. If extra
distance (CB+BD) travelled by them is equal to integral no. n of the
wavelengths.
i.e. n λ = CB+BD -----------(1)
19
20. Deviation of Bragg's equation
From the geometry we know that
CB = BD = AB sin θ ---------(2)
From (1) and (2)
𝑛λ=2AB 𝑠𝑖𝑛𝜃
𝑛λ=2𝑑 𝑠𝑖𝑛𝜃
This is known as Bragg’s Equation
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23. Rotating crystal method
A beam of x-rays of known λ falls on a face of the crystal
mounted on a graduated turn table.
The diffracted rays pass into the ionisation chamber of the
recorder.
Here they ionise the air and a current flows between the chamber
wall and the electrode inserted in it which is connected to an
electrometer.
The electrometer reading is proportional to the intensity of x-
rays
23
24. Rotating crystal method
As the recorder along with the crystal is rotated, the angles of
maximum intensity are noted on the scale.
Thus values of θ for n= 1,2,3 etc are used to calculate the
distance d between the lattice planes parallel to the face of the
crystal
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25. The powder method
In this method, the crystalline material contained in a capillary tube is
placed in the camera containing a film strip
The sample is rotated by means of a motor
The x-rays passes through the gap between the ends of the film.
The powdered sample contains small crystals arranged in all
orientations.
Some will reflect x-rays from each lattice plane at sometimes.
The reflected X-rays make an angle of 2 θ with the incident X-ray.
From the geometry of camera, θ can be calculated for different crystal
planes.
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