This slide describes about Hydrogen Evolution Reaction and effect of Cu substitution in enhancing the activity. Deconvolution of strain and ligand effect is explained in the slide and in the respective paper.
Although the inelastic scattering of light was predicted by Adolf Smekal in 1923, it was not observed in practice until 1928. The Raman effect was named after one of its discoverers, the Indian scientist C. V. Raman, who observed the effect in organic liquids in 1928 together with K. S. Krishnan, and independently by Grigory Landsberg and Leonid Mandelstam in inorganic crystals. Raman won the Nobel Prize in Physics in 1930 for this discovery. The first observation of Raman spectra in gases was in 1929 by Franco Rasetti.
ITS AGAIN AN IMPORTANT TOPIC OF ANALYTICAL CHEMISTRY WHERE C13 IS AN TYPE OF NUCLEAR MAGNETIC RESONANCE ALONG WITH PROTON NMR. STUDY THIS TOPIC WELL FOR BTTER UNDERTSANDING OF NMR WHICH IS BELIEVED TO BE ONE OF THE TOUGH PART.
HOPE YOU ALL WILL USE IT WELL.
Although the inelastic scattering of light was predicted by Adolf Smekal in 1923, it was not observed in practice until 1928. The Raman effect was named after one of its discoverers, the Indian scientist C. V. Raman, who observed the effect in organic liquids in 1928 together with K. S. Krishnan, and independently by Grigory Landsberg and Leonid Mandelstam in inorganic crystals. Raman won the Nobel Prize in Physics in 1930 for this discovery. The first observation of Raman spectra in gases was in 1929 by Franco Rasetti.
ITS AGAIN AN IMPORTANT TOPIC OF ANALYTICAL CHEMISTRY WHERE C13 IS AN TYPE OF NUCLEAR MAGNETIC RESONANCE ALONG WITH PROTON NMR. STUDY THIS TOPIC WELL FOR BTTER UNDERTSANDING OF NMR WHICH IS BELIEVED TO BE ONE OF THE TOUGH PART.
HOPE YOU ALL WILL USE IT WELL.
X-Ray photoelectron spectroscopy, XPS was used to investigate the chemistry at the surface of the samples. The basic mechanism behind an XPS instrument is that the photons of a specific energy are used to excite the electronic states of atoms at and just below the surface of the sample.
There are several areas suited to measurement by XPS:
1. Elemental composition
2. Empirical formula determination
3. Chemical state
4. Electronic state
5. Binding energy
6. Layer thickness in the upper portion of surfaces
XPS has many advantages, such as it is is good for identifying all but two elements, identifying the chemical state on surfaces, and is good with quantitative analysis. XPS is capable of detecting the difference in chemical state between samples. XPS is also able to differentiate between oxidations states of molecules.
XPS has also some limitations, for instance, samples for XPS must be compatible with the ultra high vacuum environment. XPS is limited to measurements of elements having atomic numbers of 3 or greater, making it unable to detect hydrogen or helium. XPS spectra also take a long time to obtain. The use of a monochromator can also reduce the time per experiment.
Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy or magnetic resonance spectroscopy, is a spectroscopic technique to observe local magnetic fields around atomic nuclei.
Uv-Vis spectroscopy: electronic spectroscopy, absorption and emission, Terms describing UV absorptions, absorbing species containing s,n and pi, absorbing species,sigma and pi orbitals, electronic transitions, Absorption: physical Basis and lineshape,UV-Spectra.
Localising Charged Particles by Electric and Magnetic Fields
the trapping of charged particles
Prepared By : Mohamed Fayed Mohamed Ali
Email : M10513fayed@gmail.com
X-Ray photoelectron spectroscopy, XPS was used to investigate the chemistry at the surface of the samples. The basic mechanism behind an XPS instrument is that the photons of a specific energy are used to excite the electronic states of atoms at and just below the surface of the sample.
There are several areas suited to measurement by XPS:
1. Elemental composition
2. Empirical formula determination
3. Chemical state
4. Electronic state
5. Binding energy
6. Layer thickness in the upper portion of surfaces
XPS has many advantages, such as it is is good for identifying all but two elements, identifying the chemical state on surfaces, and is good with quantitative analysis. XPS is capable of detecting the difference in chemical state between samples. XPS is also able to differentiate between oxidations states of molecules.
XPS has also some limitations, for instance, samples for XPS must be compatible with the ultra high vacuum environment. XPS is limited to measurements of elements having atomic numbers of 3 or greater, making it unable to detect hydrogen or helium. XPS spectra also take a long time to obtain. The use of a monochromator can also reduce the time per experiment.
Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy or magnetic resonance spectroscopy, is a spectroscopic technique to observe local magnetic fields around atomic nuclei.
Uv-Vis spectroscopy: electronic spectroscopy, absorption and emission, Terms describing UV absorptions, absorbing species containing s,n and pi, absorbing species,sigma and pi orbitals, electronic transitions, Absorption: physical Basis and lineshape,UV-Spectra.
Localising Charged Particles by Electric and Magnetic Fields
the trapping of charged particles
Prepared By : Mohamed Fayed Mohamed Ali
Email : M10513fayed@gmail.com
Nucleophilic Addition of carbonyl compounds.pptxSSR02
Nucleophilic addition is the most important reaction of carbonyls. Not just aldehydes and ketones, but also carboxylic acid derivatives in general.
Carbonyls undergo addition reactions with a large range of nucleophiles.
Comparing the relative basicity of the nucleophile and the product is extremely helpful in determining how reversible the addition reaction is. Reactions with Grignards and hydrides are irreversible. Reactions with weak bases like halides and carboxylates generally don’t happen.
Electronic effects (inductive effects, electron donation) have a large impact on reactivity.
Large groups adjacent to the carbonyl will slow the rate of reaction.
Neutral nucleophiles can also add to carbonyls, although their additions are generally slower and more reversible. Acid catalysis is sometimes employed to increase the rate of addition.
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.
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
hematic appreciation test is a psychological assessment tool used to measure an individual's appreciation and understanding of specific themes or topics. This test helps to evaluate an individual's ability to connect different ideas and concepts within a given theme, as well as their overall comprehension and interpretation skills. The results of the test can provide valuable insights into an individual's cognitive abilities, creativity, and critical thinking skills
Toxic effects of heavy metals : Lead and Arsenicsanjana502982
Heavy metals are naturally occuring metallic chemical elements that have relatively high density, and are toxic at even low concentrations. All toxic metals are termed as heavy metals irrespective of their atomic mass and density, eg. arsenic, lead, mercury, cadmium, thallium, chromium, etc.
Travis Hills' Endeavors in Minnesota: Fostering Environmental and Economic Pr...Travis Hills MN
Travis Hills of Minnesota developed a method to convert waste into high-value dry fertilizer, significantly enriching soil quality. By providing farmers with a valuable resource derived from waste, Travis Hills helps enhance farm profitability while promoting environmental stewardship. Travis Hills' sustainable practices lead to cost savings and increased revenue for farmers by improving resource efficiency and reducing waste.
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.
DERIVATION OF MODIFIED BERNOULLI EQUATION WITH VISCOUS EFFECTS AND TERMINAL V...Wasswaderrick3
In this book, we use conservation of energy techniques on a fluid element to derive the Modified Bernoulli equation of flow with viscous or friction effects. We derive the general equation of flow/ velocity and then from this we derive the Pouiselle flow equation, the transition flow equation and the turbulent flow equation. In the situations where there are no viscous effects , the equation reduces to the Bernoulli equation. From experimental results, we are able to include other terms in the Bernoulli equation. We also look at cases where pressure gradients exist. We use the Modified Bernoulli equation to derive equations of flow rate for pipes of different cross sectional areas connected together. We also extend our techniques of energy conservation to a sphere falling in a viscous medium under the effect of gravity. We demonstrate Stokes equation of terminal velocity and turbulent flow equation. We look at a way of calculating the time taken for a body to fall in a viscous medium. We also look at the general equation of terminal velocity.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
Deep Software Variability and Frictionless Reproducibility
Deconvolution of strain and ligand
1. “Inverse Strain Effect in Atomic Scale” -
Enhanced Hydrogen Evolution Activity and
Durability in Cu substituted Palladseite
Saurav Chandra Sarma
14/11/2018
S.C. Sarma, V. Mishra, K.A. Ann Mary, S. Roy, S.C. Peter, ACS Energy Letters, (2018)
1
2. Introduction
Pd17Se15 (CuPd)17Se15
+Cu
Standard colloidal synthesis
Hydrogen has the highest energy
content per unit mass.
Feedstock for fuel cell
Ease of production from highly
abundant water
Why Hydrogen..?? Where does Cu
substitute in
Pd17Se15 lattice?
How does Cu
substitution affect
structure and
oxidation state?
What is the driving force for the
enhancement of the electrocatalytic activity?
2
3. Where does Cu substitute in Pd17Se15 lattice?
+Cu
3
Decrease in the
(330) plane
intensity with Cu
substitution
Left shift in the
PXRD peak
position instead
of right shift
Inverse Strain
Effect
Cu
128 pm
Pd
163 pm
Se
190 pm
4. How does Cu Substitution affect Pd17Se15 lattice?
(0)
(-2)
XAFS experiment performed at P64 Beamline, PETRA III, DESY, Germany
4
5. Electrochemical Hydrogen Evolution Reaction (HER)
Onset improved
after Cu
substitution
High current
density at lower
overpotential
Pd17Se15
13.08 s-1 @200
mV
(CuPd)17Se15
126.3 s-1 @200
mV
5
7. Driving Force for Enhancement of Activity
Change in Surface Area
No significant
contribution from
surface area
7
Cdl α Surface Area
8. Substitution Effect
Ligand Effect:
Strain Effect:
Ensemble Effect:
Depends on the nature of the substituent
Depends on the size of the substituent
Depends on the coordination environment
How to
DECONVOLUTE
these effects..??
8
9. Deconvoluting Strain and Ligand Effect
a=b=c=8 Å a=b=c= 9 Å
a=b=c= 8 Å a=b=c= 9 Å
Ligand Effect Strain Effect
+Cu
Constrained lattice parameter to A
Cu- substituted
Constrained lattice parameter to B
No substitution
(CuPd)17Se15
(B)
Pd17Se15
(A)
Change in d-band center
= (d – Pd17Se15)
ɛavg=
𝐸𝜌 𝐸 𝑑𝐸
𝐸𝑓
−∞
𝜌 𝐸 𝑑𝐸
𝐸𝑓
−∞
9
10. Deconvoluting Strain, Ligand and Ensemble Effect
Selective-site blocking
10
• Pd2+ is not a good H2
adsorbing material.
• Se gets activated because of
tensile strain as well as Cu
leaching.
11. Conclusion
11
Effect of Cu
substitution
Stability for
30000 Cycles
Reason for
enhancement of
activity
Site of Cu
substitution
High TOF of
126.3 s-1.
Enhancement of
activity after Cu
substitution
Faradaic efficiency close to 100 %
was achieved.
Reason for expansion
of unit cell
H2O