This document provides an overview of radical reactions and substitution and elimination reactions. It discusses topics like radical structure and stability, patterns in radical mechanisms, chlorination of methane as an example radical reaction, and thermodynamics of halogenation reactions. It also covers substitution reaction mechanisms like SN2 and E2 elimination, how kinetics and stereochemistry provide evidence for these mechanisms, and factors that influence reaction rates and product stability.
The document summarizes a guest lecture on free radicals that covered several topics:
1. The structure and formation of free radicals through homolytic bond cleavage and their stability based on factors like conjugation and sterics.
2. Mechanisms of radical substitution reactions including neighboring group assistance and reactivity based on position.
3. Methods to characterize radicals using electron spin resonance spectroscopy.
4. Examples of radical reactions including halogenation, allylic substitution, and autooxidation.
This document provides an overview of nuclear chemistry concepts including:
1) Stable and unstable nuclides, with unstable nuclides undergoing radioactive decay through emissions like alpha particles, beta particles, and gamma rays.
2) Radioactive decay processes can be represented by nuclear equations that differ from chemical equations.
3) The rate of radioactive decay is characterized by half-life, the time for half of a radioactive sample to decay.
4) Nuclear reactions like fission and fusion involve changes to atomic nuclei and release large amounts of energy.
The document discusses organic chemistry concepts related to radical reactions. It covers topics like radical formation, halogenation of alkanes, the reaction of radicals with sigma and pi bonds, stereochemistry of halogenation, radical chain reactions, antioxidants, and radical halogenation at allylic carbons. It also discusses chlorofluorocarbons and their role in ozone layer depletion through a radical chain mechanism.
The document summarizes key concepts about elimination reactions, including the E1 and E2 mechanisms. It discusses how the identity of the base, leaving group, and substrate affect the reactivity and selectivity of elimination reactions. Stereochemistry is also addressed, including the E2 reaction's preference for the anti-periplanar orientation and consequences for cyclic substrates. The Zaitsev rule is explained for regioselectivity. Strong bases generally favor the concerted E2 mechanism while weaker bases favor the stepwise E1 mechanism.
The document summarizes a guest lecture on free radicals that covered several topics:
1. The structure and formation of free radicals through homolytic bond cleavage and their stability based on factors like conjugation and sterics.
2. Mechanisms of radical substitution reactions including neighboring group assistance and reactivity based on position.
3. Methods to characterize radicals using electron spin resonance spectroscopy.
4. Examples of radical reactions including halogenation, allylic substitution, and autooxidation.
This document provides an overview of nuclear chemistry concepts including:
1) Stable and unstable nuclides, with unstable nuclides undergoing radioactive decay through emissions like alpha particles, beta particles, and gamma rays.
2) Radioactive decay processes can be represented by nuclear equations that differ from chemical equations.
3) The rate of radioactive decay is characterized by half-life, the time for half of a radioactive sample to decay.
4) Nuclear reactions like fission and fusion involve changes to atomic nuclei and release large amounts of energy.
The document discusses organic chemistry concepts related to radical reactions. It covers topics like radical formation, halogenation of alkanes, the reaction of radicals with sigma and pi bonds, stereochemistry of halogenation, radical chain reactions, antioxidants, and radical halogenation at allylic carbons. It also discusses chlorofluorocarbons and their role in ozone layer depletion through a radical chain mechanism.
The document summarizes key concepts about elimination reactions, including the E1 and E2 mechanisms. It discusses how the identity of the base, leaving group, and substrate affect the reactivity and selectivity of elimination reactions. Stereochemistry is also addressed, including the E2 reaction's preference for the anti-periplanar orientation and consequences for cyclic substrates. The Zaitsev rule is explained for regioselectivity. Strong bases generally favor the concerted E2 mechanism while weaker bases favor the stepwise E1 mechanism.
The document discusses elimination reactions, which involve the loss of elements from a starting material to form a new π bond in the product. There are two main mechanisms for elimination reactions - E1 and E2. The E1 mechanism is unimolecular and involves the leaving group departing before π bond formation. The E2 mechanism is bimolecular and concerted, with both bond cleavages and formations occurring simultaneously. Strong bases promote the E2 mechanism, while weaker bases favor E1. The type of reaction also depends on the nucleophilicity and size of the reactants.
Nucleophilic substitution reactions can occur through either an SN1 or SN2 mechanism. The SN1 reaction is a two-step process where the first step is rate-determining and involves formation of a carbocation intermediate. It is a unimolecular reaction that results in loss of configuration. The SN2 reaction is a single concerted step where nucleophilic attack and leaving of the existing group occur simultaneously through a trigonal planar transition state. It results in inversion of configuration. Both mechanisms are affected by factors like the substrate structure, the nucleophile, the leaving group and the solvent used.
This document summarizes an experiment studying the effects of operational conditions on microbial fuel cells (MFCs) used to generate electricity from wastewater. Twelve MFC reactors were created and inoculated with microbes and swine waste. Most reactors did not survive linear sweep voltammetry testing, which stressed the microbes. The surviving reactor was subjected to a day/night cycle, but the cathode was found to be unsuitable for biofilm growth. Future plans include testing reactors before inoculation to ensure consistency and making the environment more suitable for microbes.
This is the contents of this presentation-
• The arenium ion mechanism,
• Orientation and reactivity,
• Energy profile diagrams.
• o/p ratio,
• Orientation in benzene ring with more than one substituent, orientation in other ring systems.
• ipso attack
• Diazonium coupling,
• Gatterman-Koch reaction,
• Reimer-Tiemann reaction,
• Pechman reaction,
• Houben –Hoesch reaction,
• Kolbe Schmitt reaction,
• Recapitulation of halogenation, nitration, sulphonation, and F.C. reaction.
Homogeneous catalysis refers to reactions where the catalyst is in the same phase as the reactants. Common homogeneous catalysts include acids and bases in aqueous solutions. Homogeneous catalysts can provide selectivity in terms of chemoselectivity, regioselectivity, diastereoselectivity, and enantioselectivity. Important reaction types for homogeneous catalysis include oxidative addition, reductive elimination, migratory insertion, and β-hydride elimination. Key reactions discussed are hydrogenation, hydroformylation, hydrocyanation, and applications of Ziegler-Natta catalysts and Wilkinson's catalyst. Chiral induction with chiral ligands is also discussed for producing chiral molecules in drug synthesis such as L-DOPA
Colorimetry is "the science and technology used to quantify and describe physically the human color perception".[1] It is similar to spectrophotometry, but is distinguished by its interest in reducing spectra to the physical correlates of color perception, most often the CIE 1931 XYZ color space tristimulus values and related quantities.[2]
Catalysts accelerate chemical reactions without being consumed. There are two types of catalysts: homogeneous, where the catalyst is in the same phase as the reactants, and heterogeneous, where the catalyst is in a different phase. In heterogeneous catalysis, the catalyst is typically a solid and the reactants are gases or liquids. The catalyst provides alternative reaction pathways with lower activation energies. Enzymes are biological catalysts that work by binding reactants in cavities on their surfaces, forming activated complexes that decompose into products.
The document discusses the chemical properties of alkanes and alkenes. It explains that alkanes contain carbon and hydrogen and are saturated hydrocarbons that are very stable due to strong C-H bonds. Alkanes undergo combustion and cracking reactions. Alkenes contain carbon-carbon double bonds, which make them more reactive than alkanes and allow them to undergo addition reactions with electrophiles such as halogens. The most important reaction of alkenes is polymerization, where alkene monomers combine to form large macromolecules or polymers. Common polymers include polyethylene, polypropylene, PVC, and PTFE.
The document provides information about conformations in hydrocarbons. It discusses that carbon-carbon single bonds allow rotation, leading to different conformations. Ethane is used as an example to explain staggered and eclipsed conformations. The relative stabilities of these conformations are also mentioned. Further, the document covers alkenes, alkynes and aromatic hydrocarbons. It provides their structures, properties and reactions like addition, oxidation, halogenation etc.
This document provides an overview of chemical bonding concepts including ionic bonds, covalent bonds, and metallic bonds. It discusses how ionic bonds form via the transfer of electrons between metals and nonmetals to form oppositely charged ions. Covalent bonds are described as the sharing of electrons between nonmetals. Metallic bonding is explained as a "sea of electrons" that holds positively charged metal ions in a lattice structure. The properties of ionic compounds, covalent compounds, and metals are contrasted. Examples of giant covalent structures like diamond and graphite are analyzed in terms of their bonding and properties. Learning outcomes are stated throughout to guide the reader.
This document provides an overview of chemical bonding and different types of bonds. It begins by explaining ionic bonds which are formed by the transfer of electrons between metals and non-metals. Sodium chloride is given as an example. Covalent bonds are then introduced and involve the sharing of electrons between non-metals like hydrogen and oxygen. The properties of ionic and covalent compounds are contrasted. Ionic compounds have high melting points and conduct electricity when molten or dissolved, while covalent compounds have lower melting points and do not conduct electricity. Metallic bonding is described involving positive metal ions in a "sea of electrons". Finally, macromolecular structures like diamond and graphite are discussed and how their different bonding structures
This document introduces reactions that take place at the alpha carbon of carbonyl compounds. It discusses enols and enolates, which are reactive intermediates that allow substitutions and additions to occur at the alpha carbon. Specifically, it covers alpha halogenation, aldol reactions, and aldol condensations. These reactions are important methods to form carbon-carbon bonds and install functional groups at the alpha position of carbonyls.
This document provides an overview of covalent bonding and Lewis dot structures. It begins with an introduction to covalent compounds and how covalent bonding occurs through the sharing of valence electrons between nonmetal atoms. Lewis dot structures are introduced as a way to represent covalent bonds using dots to represent valence electrons. The document then covers steps for drawing Lewis dot structures, including finding the total valence electrons, identifying the central atom, adding single bonds, and adding electrons to attain full octets. Examples of drawing Lewis structures for PCl3 and NH3 are shown. The document concludes with sections on exceptions to the octet rule and practice drawing Lewis diagrams.
Chain reactions involve reactive intermediates called chain carriers that propagate the reaction by producing more reactive intermediates. Chain reactions consist of initiation, propagation, and termination steps. The initiation step produces the first reactive intermediates. The propagation step produces more reactive intermediates from reaction of the previous intermediates. Termination stops the chain by deactivating the chain carriers. Chain reactions for forming HCl can occur thermally or photochemically. In the photochemical reaction, light initiates the production of chlorine atoms from Cl2, which then react with H2 through a series of propagation and termination steps to ultimately form HCl. The presence of oxygen complicates the reaction mechanism.
The document discusses different types of chemical bonds and macromolecular structures. It explains that ionic bonds form between metals and non-metals via the transfer of electrons, giving ionic compounds high melting points and the ability to conduct electricity when molten or dissolved. Covalent bonds form between non-metals by the sharing of electrons, resulting in covalent compounds having low melting points and the inability to conduct electricity. Some covalent substances exist as macromolecules or giant molecular structures like diamond and graphite. These have very high melting points and different properties compared to simple molecules. Metallic bonding is also described, involving positive metal ions in a "sea of electrons" giving metals properties like malleability and high conductivity
The document provides information about chemical bonding and different types of bonds. It begins by defining a chemical bond as the forces that hold groups of atoms together, and explains that bonds form when the energy of bonded atoms is lower than separated atoms. It then describes the main types of bonds:
- Ionic bonds result from the transfer of electrons between metals and nonmetals.
- Covalent bonds result from the sharing of electrons between atoms.
- Polar covalent bonds occur when electrons are unequally shared, resulting in partial charges.
The document discusses electronegativity and how it relates to bond polarity. It also introduces dipole moments and how bond polarity affects molecular properties like solubility. Finally, it explains
The document discusses several organic chemistry concepts including inductive effect, hyperconjugation, isomerism, hydrocarbons, mechanisms of aromatic substitution reactions, and the structure of benzene. It provides details on types of inductive and electromeric effects, sources of isomerism like geometrical and optical isomerism, Baeyer's strain theory explanation for cycloalkane stability, electrophilic aromatic substitution reactions like halogenation and nitration, and the historical elucidation of benzene's structure including objections to early proposals.
Catalysis Science & Technology covers both the science of catalysis and catalysis technology, including applications addressing global issues. The journal publishes research in the applied, fundamental, experimental and computational areas of catalysis. Contributions are made by the homogeneous, heterogeneous and biocatalysis communities.
1) Radical reactions involve the cleavage of covalent bonds through homolysis, producing highly reactive radical intermediates.
2) Radicals react by pairing their unpaired electrons, such as through hydrogen abstraction. Their relative stabilities follow trends similar to carbocations.
3) Alkanes undergo substitution reactions with halogens like chlorine and bromine via free radical chain mechanisms under thermal or photolytic conditions, producing mixtures of mono- and polyhalogenated products.
Elimination reactions involve the removal of two substituents from adjacent carbon atoms to form a double or triple bond. The document discusses E1 elimination reactions, which proceed through a two-step unimolecular mechanism. In the first step, a carbocation intermediate is formed. In the second step, a proton is removed from the carbocation rapidly to form the alkene product. E1 reactions favor substrates that form stable carbocations and are accelerated by polar protic solvents, weak bases, and high temperatures. The rate depends on the concentration of the substrate and the reaction follows first-order kinetics.
The technology uses reclaimed CO₂ as the dyeing medium in a closed loop process. When pressurized, CO₂ becomes supercritical (SC-CO₂). In this state CO₂ has a very high solvent power, allowing the dye to dissolve easily.
The document discusses elimination reactions, which involve the loss of elements from a starting material to form a new π bond in the product. There are two main mechanisms for elimination reactions - E1 and E2. The E1 mechanism is unimolecular and involves the leaving group departing before π bond formation. The E2 mechanism is bimolecular and concerted, with both bond cleavages and formations occurring simultaneously. Strong bases promote the E2 mechanism, while weaker bases favor E1. The type of reaction also depends on the nucleophilicity and size of the reactants.
Nucleophilic substitution reactions can occur through either an SN1 or SN2 mechanism. The SN1 reaction is a two-step process where the first step is rate-determining and involves formation of a carbocation intermediate. It is a unimolecular reaction that results in loss of configuration. The SN2 reaction is a single concerted step where nucleophilic attack and leaving of the existing group occur simultaneously through a trigonal planar transition state. It results in inversion of configuration. Both mechanisms are affected by factors like the substrate structure, the nucleophile, the leaving group and the solvent used.
This document summarizes an experiment studying the effects of operational conditions on microbial fuel cells (MFCs) used to generate electricity from wastewater. Twelve MFC reactors were created and inoculated with microbes and swine waste. Most reactors did not survive linear sweep voltammetry testing, which stressed the microbes. The surviving reactor was subjected to a day/night cycle, but the cathode was found to be unsuitable for biofilm growth. Future plans include testing reactors before inoculation to ensure consistency and making the environment more suitable for microbes.
This is the contents of this presentation-
• The arenium ion mechanism,
• Orientation and reactivity,
• Energy profile diagrams.
• o/p ratio,
• Orientation in benzene ring with more than one substituent, orientation in other ring systems.
• ipso attack
• Diazonium coupling,
• Gatterman-Koch reaction,
• Reimer-Tiemann reaction,
• Pechman reaction,
• Houben –Hoesch reaction,
• Kolbe Schmitt reaction,
• Recapitulation of halogenation, nitration, sulphonation, and F.C. reaction.
Homogeneous catalysis refers to reactions where the catalyst is in the same phase as the reactants. Common homogeneous catalysts include acids and bases in aqueous solutions. Homogeneous catalysts can provide selectivity in terms of chemoselectivity, regioselectivity, diastereoselectivity, and enantioselectivity. Important reaction types for homogeneous catalysis include oxidative addition, reductive elimination, migratory insertion, and β-hydride elimination. Key reactions discussed are hydrogenation, hydroformylation, hydrocyanation, and applications of Ziegler-Natta catalysts and Wilkinson's catalyst. Chiral induction with chiral ligands is also discussed for producing chiral molecules in drug synthesis such as L-DOPA
Colorimetry is "the science and technology used to quantify and describe physically the human color perception".[1] It is similar to spectrophotometry, but is distinguished by its interest in reducing spectra to the physical correlates of color perception, most often the CIE 1931 XYZ color space tristimulus values and related quantities.[2]
Catalysts accelerate chemical reactions without being consumed. There are two types of catalysts: homogeneous, where the catalyst is in the same phase as the reactants, and heterogeneous, where the catalyst is in a different phase. In heterogeneous catalysis, the catalyst is typically a solid and the reactants are gases or liquids. The catalyst provides alternative reaction pathways with lower activation energies. Enzymes are biological catalysts that work by binding reactants in cavities on their surfaces, forming activated complexes that decompose into products.
The document discusses the chemical properties of alkanes and alkenes. It explains that alkanes contain carbon and hydrogen and are saturated hydrocarbons that are very stable due to strong C-H bonds. Alkanes undergo combustion and cracking reactions. Alkenes contain carbon-carbon double bonds, which make them more reactive than alkanes and allow them to undergo addition reactions with electrophiles such as halogens. The most important reaction of alkenes is polymerization, where alkene monomers combine to form large macromolecules or polymers. Common polymers include polyethylene, polypropylene, PVC, and PTFE.
The document provides information about conformations in hydrocarbons. It discusses that carbon-carbon single bonds allow rotation, leading to different conformations. Ethane is used as an example to explain staggered and eclipsed conformations. The relative stabilities of these conformations are also mentioned. Further, the document covers alkenes, alkynes and aromatic hydrocarbons. It provides their structures, properties and reactions like addition, oxidation, halogenation etc.
This document provides an overview of chemical bonding concepts including ionic bonds, covalent bonds, and metallic bonds. It discusses how ionic bonds form via the transfer of electrons between metals and nonmetals to form oppositely charged ions. Covalent bonds are described as the sharing of electrons between nonmetals. Metallic bonding is explained as a "sea of electrons" that holds positively charged metal ions in a lattice structure. The properties of ionic compounds, covalent compounds, and metals are contrasted. Examples of giant covalent structures like diamond and graphite are analyzed in terms of their bonding and properties. Learning outcomes are stated throughout to guide the reader.
This document provides an overview of chemical bonding and different types of bonds. It begins by explaining ionic bonds which are formed by the transfer of electrons between metals and non-metals. Sodium chloride is given as an example. Covalent bonds are then introduced and involve the sharing of electrons between non-metals like hydrogen and oxygen. The properties of ionic and covalent compounds are contrasted. Ionic compounds have high melting points and conduct electricity when molten or dissolved, while covalent compounds have lower melting points and do not conduct electricity. Metallic bonding is described involving positive metal ions in a "sea of electrons". Finally, macromolecular structures like diamond and graphite are discussed and how their different bonding structures
This document introduces reactions that take place at the alpha carbon of carbonyl compounds. It discusses enols and enolates, which are reactive intermediates that allow substitutions and additions to occur at the alpha carbon. Specifically, it covers alpha halogenation, aldol reactions, and aldol condensations. These reactions are important methods to form carbon-carbon bonds and install functional groups at the alpha position of carbonyls.
This document provides an overview of covalent bonding and Lewis dot structures. It begins with an introduction to covalent compounds and how covalent bonding occurs through the sharing of valence electrons between nonmetal atoms. Lewis dot structures are introduced as a way to represent covalent bonds using dots to represent valence electrons. The document then covers steps for drawing Lewis dot structures, including finding the total valence electrons, identifying the central atom, adding single bonds, and adding electrons to attain full octets. Examples of drawing Lewis structures for PCl3 and NH3 are shown. The document concludes with sections on exceptions to the octet rule and practice drawing Lewis diagrams.
Chain reactions involve reactive intermediates called chain carriers that propagate the reaction by producing more reactive intermediates. Chain reactions consist of initiation, propagation, and termination steps. The initiation step produces the first reactive intermediates. The propagation step produces more reactive intermediates from reaction of the previous intermediates. Termination stops the chain by deactivating the chain carriers. Chain reactions for forming HCl can occur thermally or photochemically. In the photochemical reaction, light initiates the production of chlorine atoms from Cl2, which then react with H2 through a series of propagation and termination steps to ultimately form HCl. The presence of oxygen complicates the reaction mechanism.
The document discusses different types of chemical bonds and macromolecular structures. It explains that ionic bonds form between metals and non-metals via the transfer of electrons, giving ionic compounds high melting points and the ability to conduct electricity when molten or dissolved. Covalent bonds form between non-metals by the sharing of electrons, resulting in covalent compounds having low melting points and the inability to conduct electricity. Some covalent substances exist as macromolecules or giant molecular structures like diamond and graphite. These have very high melting points and different properties compared to simple molecules. Metallic bonding is also described, involving positive metal ions in a "sea of electrons" giving metals properties like malleability and high conductivity
The document provides information about chemical bonding and different types of bonds. It begins by defining a chemical bond as the forces that hold groups of atoms together, and explains that bonds form when the energy of bonded atoms is lower than separated atoms. It then describes the main types of bonds:
- Ionic bonds result from the transfer of electrons between metals and nonmetals.
- Covalent bonds result from the sharing of electrons between atoms.
- Polar covalent bonds occur when electrons are unequally shared, resulting in partial charges.
The document discusses electronegativity and how it relates to bond polarity. It also introduces dipole moments and how bond polarity affects molecular properties like solubility. Finally, it explains
The document discusses several organic chemistry concepts including inductive effect, hyperconjugation, isomerism, hydrocarbons, mechanisms of aromatic substitution reactions, and the structure of benzene. It provides details on types of inductive and electromeric effects, sources of isomerism like geometrical and optical isomerism, Baeyer's strain theory explanation for cycloalkane stability, electrophilic aromatic substitution reactions like halogenation and nitration, and the historical elucidation of benzene's structure including objections to early proposals.
Catalysis Science & Technology covers both the science of catalysis and catalysis technology, including applications addressing global issues. The journal publishes research in the applied, fundamental, experimental and computational areas of catalysis. Contributions are made by the homogeneous, heterogeneous and biocatalysis communities.
1) Radical reactions involve the cleavage of covalent bonds through homolysis, producing highly reactive radical intermediates.
2) Radicals react by pairing their unpaired electrons, such as through hydrogen abstraction. Their relative stabilities follow trends similar to carbocations.
3) Alkanes undergo substitution reactions with halogens like chlorine and bromine via free radical chain mechanisms under thermal or photolytic conditions, producing mixtures of mono- and polyhalogenated products.
Elimination reactions involve the removal of two substituents from adjacent carbon atoms to form a double or triple bond. The document discusses E1 elimination reactions, which proceed through a two-step unimolecular mechanism. In the first step, a carbocation intermediate is formed. In the second step, a proton is removed from the carbocation rapidly to form the alkene product. E1 reactions favor substrates that form stable carbocations and are accelerated by polar protic solvents, weak bases, and high temperatures. The rate depends on the concentration of the substrate and the reaction follows first-order kinetics.
The technology uses reclaimed CO₂ as the dyeing medium in a closed loop process. When pressurized, CO₂ becomes supercritical (SC-CO₂). In this state CO₂ has a very high solvent power, allowing the dye to dissolve easily.
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
ESA/ACT Science Coffee: Diego Blas - Gravitational wave detection with orbita...Advanced-Concepts-Team
Presentation in the Science Coffee of the Advanced Concepts Team of the European Space Agency on the 07.06.2024.
Speaker: Diego Blas (IFAE/ICREA)
Title: Gravitational wave detection with orbital motion of Moon and artificial
Abstract:
In this talk I will describe some recent ideas to find gravitational waves from supermassive black holes or of primordial origin by studying their secular effect on the orbital motion of the Moon or satellites that are laser ranged.
Authoring a personal GPT for your research and practice: How we created the Q...Leonel Morgado
Thematic analysis in qualitative research is a time-consuming and systematic task, typically done using teams. Team members must ground their activities on common understandings of the major concepts underlying the thematic analysis, and define criteria for its development. However, conceptual misunderstandings, equivocations, and lack of adherence to criteria are challenges to the quality and speed of this process. Given the distributed and uncertain nature of this process, we wondered if the tasks in thematic analysis could be supported by readily available artificial intelligence chatbots. Our early efforts point to potential benefits: not just saving time in the coding process but better adherence to criteria and grounding, by increasing triangulation between humans and artificial intelligence. This tutorial will provide a description and demonstration of the process we followed, as two academic researchers, to develop a custom ChatGPT to assist with qualitative coding in the thematic data analysis process of immersive learning accounts in a survey of the academic literature: QUAL-E Immersive Learning Thematic Analysis Helper. In the hands-on time, participants will try out QUAL-E and develop their ideas for their own qualitative coding ChatGPT. Participants that have the paid ChatGPT Plus subscription can create a draft of their assistants. The organizers will provide course materials and slide deck that participants will be able to utilize to continue development of their custom GPT. The paid subscription to ChatGPT Plus is not required to participate in this workshop, just for trying out personal GPTs during it.
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...Scintica Instrumentation
Targeting Hsp90 and its pathogen Orthologs with Tethered Inhibitors as a Diagnostic and Therapeutic Strategy for cancer and infectious diseases with Dr. Timothy Haystead.
When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
ESR spectroscopy in liquid food and beverages.pptxPRIYANKA PATEL
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.