The document discusses radioactivity and the characteristics of different types of radiation. It describes how a Geiger-Muller tube can be used to detect radioactivity by counting voltage pulses produced when radiation interacts with the gas inside the tube. Alpha particles have a high ionizing power but low penetration, beta particles can pass through paper but are stopped by aluminum, and gamma rays are highly penetrating. Half-life is defined as the time for half of radioactive nuclei to decay and can be measured using a GM tube and counting rate over time. Nuclear reactions like fission and fusion are discussed where energy is released due to mass loss.
This would enable students to explain the emission spectrum of hydrogen using the Bohr model of the hydrogen atom; calculate the energy, wavelength, and frequencies involved in the electron transitions in the hydrogen atom; relate the emission spectra to common occurrences like fireworks and neon lights; and describe the Bohr model of the atom and the inadequacies of the Bohr model.
This is a pdf file on the topic Gamow theory of alpha decay which gives description about how the scientist Gamow had solved the theory of the alpha decay via tunneling .
This would enable students to explain the emission spectrum of hydrogen using the Bohr model of the hydrogen atom; calculate the energy, wavelength, and frequencies involved in the electron transitions in the hydrogen atom; relate the emission spectra to common occurrences like fireworks and neon lights; and describe the Bohr model of the atom and the inadequacies of the Bohr model.
This is a pdf file on the topic Gamow theory of alpha decay which gives description about how the scientist Gamow had solved the theory of the alpha decay via tunneling .
In these slides, I covered the following topics with PYQ's of CH-12 (Atom) of class 12th Physics:
-Alpha-particle scattering experiment
-Rutherford's model of the atom
-Bohr model,
-Energy levels,
-Hydrogen spectrum
The Stefan–Boltzmann constant (also Stefan's constant), a physical constant denoted by the Greek letter σ, is the constant of proportionality in the Stefan–Boltzmann law: the total energy radiated per unit surface area of a black body in unit time is proportional to the fourth power of the thermodynamic temperature.
At the end of this chapter you should be able to sketch the periodic table showing the groups and periods; identify the metals, metalloids and non-metals in the periodic table. Identify the representative elements, the transition elements, the transition metals, the lanthanides and actinides in the periodic table. Also, give the electron configuration of cations and anions; determine the trends in the physical properties of elements in a group; describe and explain the trends in atomic properties in the periodic table; compare the properties of families and elements; predict the properties of individual elements based on their position in the periodic table; and perform exercises and collaborative work with peers.
In these slides, I covered the following topics with PYQ's of CH-12 (Atom) of class 12th Physics:
-Alpha-particle scattering experiment
-Rutherford's model of the atom
-Bohr model,
-Energy levels,
-Hydrogen spectrum
The Stefan–Boltzmann constant (also Stefan's constant), a physical constant denoted by the Greek letter σ, is the constant of proportionality in the Stefan–Boltzmann law: the total energy radiated per unit surface area of a black body in unit time is proportional to the fourth power of the thermodynamic temperature.
At the end of this chapter you should be able to sketch the periodic table showing the groups and periods; identify the metals, metalloids and non-metals in the periodic table. Identify the representative elements, the transition elements, the transition metals, the lanthanides and actinides in the periodic table. Also, give the electron configuration of cations and anions; determine the trends in the physical properties of elements in a group; describe and explain the trends in atomic properties in the periodic table; compare the properties of families and elements; predict the properties of individual elements based on their position in the periodic table; and perform exercises and collaborative work with peers.
Detection of Radioactivity
Characteristics of the Three Types of Emission
Nuclear Reactions
Half-Life
Uses of Radioactive Isotopes Including Safety Precautions
Radioactivity, Alpha radiation, Beta radiation, Gamma radiation, Types of radiation, properties of alpha, beta and gamma radiations, Half-life of radioactive substances, Methods to measure radioactivity, Radioactive isotopes, Isotopes of Hydrogen, Isotopes of Carbon, Sodium Iodide -131, Medicinal uses of Sodium Iodide - 131, Storage of radioactive substances, Precautions in the handling of Radioactive substances, Applications of Radiopharmaceuticals
Here we will discover a new type of chemical change in which an atom changes from one element to another by nuclear transformations. Here we will also learn about nuclear radiation.
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.
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.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
Salas, V. (2024) "John of St. Thomas (Poinsot) on the Science of Sacred Theol...Studia Poinsotiana
I Introduction
II Subalternation and Theology
III Theology and Dogmatic Declarations
IV The Mixed Principles of Theology
V Virtual Revelation: The Unity of Theology
VI Theology as a Natural Science
VII Theology’s Certitude
VIII Conclusion
Notes
Bibliography
All the contents are fully attributable to the author, Doctor Victor Salas. Should you wish to get this text republished, get in touch with the author or the editorial committee of the Studia Poinsotiana. Insofar as possible, we will be happy to broker your contact.
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.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
1. RADIOACTIVITY!
Introduction:
Hey everyone! Today we’ll study about radioactive substances and the characteristics of the radiations they emit.
Radioactivity:
There are certain elements such as Radium which emit radiations. Such elements are called radioactive elements
and this phenomenon is called radioactivity. These radiations that these substances emit are of three types known as
alpha (α) particles, beta (β) particles and gamma (γ) rays.
Detection of Radioactivity:
There are several methods to detect the radioactivity, but the one that we’ll study is that using the Geiger-Muller tube
(G-M tube). It is the most sensitive detection device.
Now to coming to how it is used, here is how it actually looks like:
GM tube is basically a cylinder filled with a gas at low pressure. When alpha, beta or gamma radiations enter the
tube, they produce ions in the gas. The ions created in the gas enable the tube to conduct. A current is produced in
the tube for a short time. The current produces a voltage pulse. Each voltage pulse corresponds to one ionising
radiation entering the GM tube. The voltage pulse is amplified and counted. As shown, the tube is connected to the
counting circuit (rate meter) which counts this voltage pulse.
Now if you remove the radioactive source, the GM tube will still register a count of about 20 to 50 per minute. Why is
this? It’s due to the background radiations which are always present. This is called the background count. It is
subtracted from the final measurements if the emission rate form the radioactive source is low but if the rate is high, it
may be ignored without affecting the accuracy.
Characteristics of Alpha, Beta and Gamma:
1. Nature
What are these particles, actually? Okay. Alpha is the helium nucleus, not the helium atom itself, but the nucleus
only. We know that a nucleus carries positive charge, so alpha is a positively charged helium nucleus containing two
protons and two neutrons.
Beta particles are high-energy electrons and we know electrons carry negative charge.
Gamma rays, which we know are a part of electromagnetic spectrum, are those with the highest frequency in the
spectrum. Or we can say, rays with very short wavelength.
2. Ionizing effect
2. When fast moving alpha or beta particles collide with an atom, the atom becomes charged as an electron may be
ejected from it. Alpha particles have a very high ionizing power while beta particles have a small amount of it.
Gamma rays hardly ionize as they carry no charge.
3. Penetration
In the diagram above, you can see that an alpha particle cannot pass through paper. This is because it is a heavy
particle (a helium nucleus). Beta particles (electrons) can easily pass through paper while they are stopped by a 5mm
thick aluminium sheet. Gamma rays, on the other hand, are highly penetrating as they can pass easily through both
paper and aluminium. A 2cm thick lead can stop gamma rays.
4. Deflection
If these particles are placed in a magnetic field, they will be deflected. We have already studied in the tutorial on
Electromagnetism of how positive and negative charges are deflected in magnetic field. In this case, the same is
going to happen. The alpha particle will behave like a positive charge while a beta particle will behave like a negative
charge. The gamma rays are uncharged, hence they will be undeflected. The diagram makes it clearer:
Do you notice that the deflection of beta particles is much higher than alpha particles? Why is that? It’s due to their
masses. Electron has a mass nothing compared to the helium nucleus.
5. Speed
The speed of gamma rays will be that of the waves in electromagnetic spectrum i.e. 3 x 108
m/s.
3. The speed of beta particles is just less than that of gamma rays. While alpha particles have a lower speed compared
to both as it is a heavier particle. It’s speed is 107
m/s.
Half-Life:
Emission of these radiations occur randomly over time as a result of radioactive decay. Radioactive decay is a
process when a group of unstable nuclei decay to form stable nuclei. Half life of a sample of radioactive element is
the time taken for half of the unstable nuclei to decay.
The rate of decay at different times is called activity. Different elements have different half lives. It can be as much as
hundreds of years or as little as few hours. It depends. The activity (rate of decay) can be found using a GM tube
along with a counter.
The diagram shows how. The detector is the GM tube.
The count rate is measured at several intervals of time. Then a graph is plotted of count rate against time as shown:
Now initially, the count is 80. We have to calculate the half life of this certain element. Half life is the time taken for
half the particles to decay. That means time taken for 40, right? Now you should know how to read the graph, for 40 it
takes 6 days. Now 6 days is One half life. Two half lives means time taken for half of the first half particles, as in
further half, which is 20. It takes 12 days. For 10, 18 days. And so on..
4. The same graph with half-lives is shown.
Model of atom:
Rutherford, a scientist, performed an experiment where he aimed a source emitting a beam of alpha particles at a
thin piece of gold foil. Most of these passed straight through the gold-foil while a very small fraction of alpha particles
bounced back towards the source.
The diagram shows how this happens.
To see it closely for one atom, take a look at this diagram:
5. A strong repulsive force between alpha particles (which carry positive charge, we know) and gold nucleus (which
carries positive charge as well).
Nuclear Reactions:
Radioactive decay can be shown using nuclear equations. The parent nuclide X which is unstable is changed into Y,
which is more stable, with the emission of an alpha particle, a beta particle or gamma rays. Lets learn these three
different types of equations.
1. Alpha Decay
This is the general equation for alpha decay:
Q here is the energy released.
Consider the decay of Polonium as an example.
Energy (not shown) is also released.
2. Beta Decay
The general equation for beta decay:
Now take carbon as an example, this will be the equation for its decay.
3. Gamma decay
This is the general equation for gamma decay:
The * indicates unstable form or excited state of X. At this moment, gamma rays are emitted.
Nuclear Fission:
Uranium-236 is an isotope of uranium and is unstable, so it breaks down into two nearly equal nuclei. The equation
for this is:
6. As you can see that in nuclear fission a larger particle is broken down into smaller ones. Now coming to fusion, it’s
opposite.
Nuclear Fusion:
In fusion, however, smaller particles ‘fuse’ together, as the name indicates, and form a larger one. Energy is released
in this process.In both situations, energy is released due to loss in mass.
7. As you can see that in nuclear fission a larger particle is broken down into smaller ones. Now coming to fusion, it’s
opposite.
Nuclear Fusion:
In fusion, however, smaller particles ‘fuse’ together, as the name indicates, and form a larger one. Energy is released
in this process.In both situations, energy is released due to loss in mass.