Public Articles
On the sources of systemic risk in cryptocurrency markets
Exploring historical conceptualization of AI Stable Diffusion Model with prompt engineering techniques.
Chemistry, WM Revision Notes
Polar due to O-H bond
Able to hydrogen bond
Explains why alcohols have higher MBP’s than corresponding alkanes
Also explains why alcohol and water mix
O-H bond becomes less influential in longer chains
Solubility in water decreases
Other properties more similar to those of corresponding alkanes
Primary alcohols:
-O-H carbon bonded to one other
Secondary alcohols:
-O-H carbon bonded to two others
Tertiary alcohols:
-O-H carbon bonded to three others
The O-H group is oxidised by strong oxidising agents
Acidified Potassium Dichromate(VI), K2Cr2O7
Orange dichromate ion reduced to green chromate(III) ion
Cr2O72− ⇒ Cr3+
O-H group converted to carbonyl C=O group
Will not take place if there is no hydrogen attached to the carbon
Carbonyl formed depends on reacting alcohol and conditions
Aldehyde or ketone
Safer when using volatile compounds
Prevents loss of solvent, reagent, or product
Initially oxidised to an Aldehyde
Can be further oxidised to a Carboxylic Acid
Excess oxidising agent
Under reflux
If the Aldehyde is required:
Distilled in situ
Prevents further oxidation
Excess Alcohol
No reflux
Chemistry, All Storylines
All matter was contained in a singularity
Expansion from Big Bang
Hydrogen and Helium nuclei form after 3 minutes
Electron slow enough to form atoms after 10,000 years
Universe primarily Hydrogen and Helium
Matter formed gas clouds as Universe cooled
Clouds compressed, forming plasma of ionised atoms and unbound electrons
Nuclear fusion begins, giving a star
Stellar wind drives away dust cloud, forming planets
Nuclear fusion common in centres of stars
Lighter nuclei fused together to form heavier nuclei, releasing large amounts of energy
Requires extreme temperature and pressure
Completely renewable
Layers of elements form in star, heaviest at centre
Fusion of heavy elements due to increased pressure from star
When iron nuclei in core fuse, energy is absorbed
An iron core will cause a supernova
Longer life cycle than heavier stars
Will produce energy until all hydrogen is used
Expands into red giant after all energy is used
Red giant becomes unstable and outer gases drift away
Collapses down to White Dwarf, 1% of original stars size
Physics, Electricity, 13-14
\begin{equation*} \text{Power}=\frac{\text{Energy Transferred}}{\text{Time}} \end{equation*} Power is measured in watts, and energy in joules. Alternatively, one kilowatt-hour is the energy transferred in one hour from a source of power 1000W; 3.6MJ.
Current is a flow of charge. Charge itself is a fundamental property of matter. Charge can be positive or negative, and opposite charges attract. Charge itself is measured in coulombs, with the charge on one electron being −1.6 × 10−19C.
Conduction is the flow of electric charges through a material. An insulator is a material that will not readily conduct electricity, as it has no free charges - the tightly bound electrons would require a relatively large amount of energy to be freed.
By rubbing together two insulators, electrons are transferred from one material to another, leaving neither material with a neutral charge.
Metals are good conductors due to the fact that some of their atomic electrons are free to move between atoms and carry charge.
Electrostatic phenomena are when there is no flow of continuous charge. A continuous charge is known as a current. \begin{equation*}
Q=It
\end{equation*} The direction of conventional current is from positive to negative. However electrons, being negatively charged, flow from negative to positive.
Current is the rate of flow of charge: With a current of one ampere, one coulomb will pass a given point every second.
An electric current will be set up in a conductor if there is:
An energy source, such as a battery made up of cells
A continuous circuit
Charge is conserved wiothin a circuit. At any given point, the input and output charge must be equal - Kirchoff’s First Law
In a series circuit, current is the same everywhere. In a parallel circuit, the sum of the current in branches is equal to the total current.
Chemistry, O Revision Notes
Ionic solids are held together by opposite charges
Anions and Cations form giant ionic lattice
Eg. NaCl
Each Na+ ion surrounded by six Cl− ions and vice versa
Overall attraction within lattice greater than repulsion
Strong melting and boiling points
Many ionic substances dissolve readily in water
Ions becomes surrounded by water and spread out
Ions lose regular arrangement - becomes random
Ions behave independently of each other
Not all ionic substances dissolve readily in solution, as energy changes are an important factor.
Before an ionic solid can dissolve, the ions must be separated from their lattice. Energy must be supplied to overcome the electrostatic attractions, making it an endothermic process.
ΔLEH is the enthalpy change when one mole of a solid is formed from its separated ions in their gaseous states.
Energy required to form a lattice is negative
Energy required to break a lattice is therefore −ΔLEH
Lattice enthalpy is affected by both the charge and radii of the ions.
A greater charge will increase the magnitude of the lattice enthalpy
A greater atomic radii will decrease the magnitude of the lattice enthalpy
Larger separation between charges leads to smaller attraction
The magnitude of the lattice enthalpy will increase with greater charge density
Thus, substances with large enthalpies are normally insoluble
A2 Physics, Turning Points in Physics
Stream of electrons; current
Produced in discharge tubes
Low pressure tube with a high potential difference
Hot cathode emits electrons by thermionic emission and accelerates them through gas
Gas atoms are ionised, so have a positive charge
Low pressure allows them to accelerate towards cathode with few collisions
Collision with cathode releases more electrons
Gas is therefore conducting
De-excitation of electrons in gas atoms gives off visible and UV photons
Gas at very low pressure will have fewer collisions with electrons
Cathode ray hits glass in tube, exciting glass electrons
Glass then glows due to de-excitation
The emission of electrons from a hot cathode is known as thermionic emission.
Few electrons in the lattice are delocalised throughout crystal lattice
Allow conduction
The work function gives the minimum energy to remove one of these electrons
Heating of cathode transfers energy to free electrons
Overcome attractive electrical force of lattice
Emitted from metal surface
Thermionic emission does not require a gas to be present. An electron beam will be formed in an evacuated tube as the electrons do not collide; this is the bases of a thermionic valve.
Contain an electron gun
Annular anode helps acceleration
The cathode can be heated directly or indirectly.
Direct Heating
Tungsten filament with zirconium dioxide
Zirconium Dioxide reduces work function, resulting in greater rate of electron emission
Indirect Heating
Electric filament heats a separate cathode
Made of nickel, coated in oxides of barium calcium and aluminium
Operates efficiently at lower temperatures
Work done on a charged particle accelerating between a potential difference is given by W = QV. So, for an electron, \begin{gather*} W=eV\\ \therefore E_k=eV\\ \therefore \frac{1}{2}mv^2=eV \end{gather*} This gives the definition of the electronvolt; the energy gained by an electron after it has been accelerated through a potential difference of 1V.
Biomolecular Histology as a Novel Proxy for Ancient DNA and Protein Sequence Preservation
Topical Review: Extracting Molecular Frame Photoionization Dynamics from Experimental Data
and 1 collaborator
Community support intensity in urban settings: an empirical, place based model
The promise and challenges of characterising genome-wide structural variants: A case study in a critically endangered parrot
and 4 collaborators
olddraft
and 1 collaborator
Angular momentum transport within evolved low-mass stars
and 4 collaborators
Asteroseismology of 1.0 − 2.0M⊙ red giants by the Kepler satellite has enabled the first definitive measurements of interior rotation in both first ascent red giant branch (RGB) stars and those on the Helium burning clump. The inferred rotation rates are 10 − 30 days for the ≈0.2M⊙ He degenerate cores on the RGB and 30 − 100 days for the He burning core in a clump star. Using the MESA code we calculate state-of-the-art stellar evolution models of low mass rotating stars from the zero-age main sequence to the cooling white dwarf (WD) stage. We include transport of angular momentum due to rotationally induced instabilities and circulations, as well as magnetic fields in radiative zones (generated by the Tayler-Spruit dynamo). We find that all models fail to predict core rotation as slow as observed on the RGB and during core He burning, implying that an unmodeled angular momentum transport process must be operating on the early RGB of low mass stars. Later evolution of the star from the He burning clump to the cooling WD phase appears to be at nearly constant core angular momentum. We also incorporate the adiabatic pulsation code, ADIPLS, to explicitly highlight this shortfall when applied to a specific Kepler asteroseismic target, KIC8366239.
The question of proximity. Demographic ageing places the 15-minute-city theory under stress
Chromosome-level genome assembly of a triploid poplar Populus alba ’Berolinensis’
and 17 collaborators
A 3D View of Orion: I. Barnard’s Loop
and 12 collaborators
Barnard’s Loop is a famous arc of H\(\alpha\) emission located in the Orion star-forming region. Here, we provide evidence of a possible formation mechanism for Barnard’s Loop and compare our results with recent work suggesting a major feedback event occurred in the region around 6 Myr ago. We present a 3D model of the large-scale Orion region, indicating coherent, radial, 3D expansion of the OBP-Near/Briceño-1 (OBP-B1) cluster in the middle of a large dust cavity. The large-scale gas in the region also appears to be expanding from a central point, originally proposed to be Orion X. OBP-B1 appears to serve as another possible center, and we evaluate whether Orion X or OBP-B1 is more likely to be the cause of the expansion. Recent 3D dust maps are used to characterize the 3D topology of the entire region, which shows Barnard’s Loop’s correspondence with a large dust cavity around the OPB-B1 cluster. The molecular clouds Orion A, Orion B, and Orion \(\lambda\) reside on the shell of this cavity. Simple estimates of gravitational effects from both stars and gas indicate that the expansion of this asymmetric cavity likely induced anisotropy in the kinematics of OBP-B1. We conclude that feedback from OBP-B1 has affected the structure of the Orion A, Orion B, and Orion \(\lambda\) molecular clouds and may have played a major role in the formation of Barnard’s Loop.
Preserving tracer correlations in atmospheric transport models
and 2 collaborators
American Sociological Review
Kazuo Ishiguro and “Godi Media”: A Reading of his Select Novels and the Post-2014 Indian Media
Integral transforms of the Hilfer-type fractional derivatives
and 2 collaborators
In this paper, some important properties concerning the Hilfer-type fractional derivatives are discussed. Integral transforms for these operators are derived as particular cases of the Jafari transform. These integral transforms are used to derive a fractional version of the fundamental theorem of calculus.
Keywords: Integral transforms, Jafari transform, κ-gamma function, κ-beta function, κ-Hilfer fractional derivative, κ-Riesz fractional derivative, κ-fractional operators, (κ, ρ)-Hilfer fractional derivative.
Predictive Learning of Error Recovery with a Sensorised Passivity-based Soft Anthropomorphic Hand
and 2 collaborators
Manipulation strategies based on the passive dynamics of soft-bodied interactions provide robust performances with limited sensory information. They utilise the kinematic structure and passive dynamics of the body to adapt to objects of varying shapes and properties. However, these soft passive interactions make the state of the robotic device influenced by the environment, making control generation and state estimation difficult. This work presents a closed-loop framework for dynamic interaction-based grasping that relies on two novelties: (i) a wrist-driven passive soft anthropomorphic hand that can generate robust grasp strategies using one-step kinaesthetic teaching and (ii) a learning-based perception system that uses temporal data from sparse tactile sensors to predict and adapt to failures before it happens. With the anthropomorphic soft design and wrist-driven control, we show that controllers can be generated robust to novel objects and location uncertainty. With the learning-based high-level perception system and 32 sensing receptors, we show that failures can be predicted in advance, further improving the robustness of the entire system by more than doubling the grasping success rate. From over 1000 real-world grasping trials, both the control and perception framework are also seen to be transferable to novel objects and conditions.
Corresponding author(s) Email: [email protected]
LEADS+ Developmental Model: Proposing a new model based on an integrative conceptual review
and 4 collaborators