June 25, 2014
by Alexander Jantzen
Alexander Jantzen – ‘Enhanced sensitivity Golay cell’
In recent years there has been great advancements in production of Terahertz (THz) emitters, which in turn have lead to a need in developing new reliable, sensitive detection mechanism. Terahertz refers to the part of the electromagnetic spectrum with a frequency of 109 Hz. Specifically THz radiation is consider to be in the region from 0.3 THz to 30 THz, bridging the gap between infrared and microwaves. The most common way of measuring THz radiation is using a time domain spectrometer (TDS) as it has a very high signal-to-noise ratio, however it has to be used as an emitter/receiver package preventing detection of asynchronous THz emission.
Now that the THz region is more easily accessible, part in thanks to the development of the quantum cascade laser (QCL), it is finding its way into an increasingly wide variety of applications. A few examples of this are, non-invasive detection of cancerous cells, material analysis, homeland security, information and communications technology, and more.
The current alternative to a TDS is using a bolometer, however it suffers from difficult operation and is impractical due to it requiring liquid Helium temperatures. Golay cells were forgotten for many years, but recently started to compete with bolometers as they are far more practical, cheaper and are slowly becoming as sensitive in the infrared/THz region.
Picture 1 & 2, THz Time Domain Spectrometer with receiver-transmitter package (left) and a Quantum Cascade Laser with a Golay cell detector (right).
I have just finished my 3rd year of my Masters of Physics with experimental research (MPhys) and I will be spending my summer working on the project of enhancing the sensitivity of a Golay cell through applying physical principles and engineering solutions. A Golay cell is an apparatus based on the simple concept of thermal expansion of a gas caused by THz radiation, whereby a membrane will push outwards. This expansion can be measured by deflecting an optical beam off the membrane, allowing the intensity of THz radiation to be determined. My aim is to finalise a design for a Golay cell allowing us to create them on site. Then, further to this, apply an interferometer to our cells thereby allowing for increased sensitivity of the measurements. Through refining the design and quantising the error sources, the overarching goal for the future will be to make a “Golay Camera”.
Picture 3, Interference pattern from interferometer.
I will continue to work on this project beyond the summer as I intend to use it as my final year, masters research project. During this I expect that an array or a matrix of cells can be used to generate a camera for THz, which currently no company manufacture. This suggests to me that, with a good design, an industrial collaboration could be a very plausible outcome for the final product.
June 25, 2014
by Christopher Dawson
Chris Dawson – ‘Cavity Cooling of the motion of Nanoparticles’
My name is Chris Dawson, and I am an undergraduate and have recently finished the third year of my four year ‘Physics with Photonics’ MPhys course at the University of Southampton. My internship is with the ‘Nano’ USRG in the School of Physics and Astronomy. I will be working with Dr Hendrik Ulbricht, a researcher in the department, as well as a Phd student and a post-doc. We will be investigating the Cavity Cooling of the motion of Nanoparticles.
Cooling the motion of atoms was the starting point of a very active research field for quantum optics experiments. The extension of the ability to cool much more massive particles to the current tool set would enable a number of interesting experiments and applications. Interestingly, the same cooling principle – sideband resolved resonant cooling – as used for trapping ions and neutral atoms, can be applied to very massive opto-mechanical systems. This is the method that we will be using in the summer.
In this project we will trap a single dielectric polyethylene nanoparticle in the optical field inside a laser cavity and use the detuning of the optical resonance to the mechanical resonance to achieve sideband resolved cooling. The first step will be to lock a cavity to a stabilized laser (1kHz linewidth) at 1550 nm. This should be achieved during the period of the summer project. This will be the first part of a much more long term project in which we will be attempting to cool these nanoparticles in incredibly low temperatures, entering a regime in which the movement of the particles begins to obey a very bizarre set of quantum behaviours. This research could be a step towards systems that will be used in ultra-high precision sensing devices.
The internship project will lead on to my Masters final project next year in which myself and another undergraduate will continue this research.
June 24, 2014
by Peter Prince
Peter Prince: ‘An agent-based model to explore time allocation towards foraging in response to rainfall and temperature conditions in large African herbivores’
I am a computer science student moving from my third year to my final Masters year in September. I have an existing interest in ecological modelling, previous creating an agent-based model of brown bears, attempting to minimise fatal interactions between humans and bears in American national parks. My interest in this field comes from wanting to take computer science knowledge I’ve gained and use it to help solve problems in other fields, such as ecological problems.
The plan for the research project is based on GPS tracking data on a number of large herbivores in Africa. Over a number of years a large dataset has been amassed, documenting the movement of various species such as antelope, wildebeest and buffalo across areas of Africa. By exploring the work done in previous papers on similar data, the idea of exploring the behaviour of certain herbivores in response to drought and extreme temperatures was decided upon.
For some species, effects such as high rainfall have been shown to cause population declines due to increased predation when foraging at night. However, certain species experience declines after periods of high rainfall, with long grass growing and providing more cover for predators during the day. It is effects such as these which our project aims to explore, optimising time allocation throughout the day and night.
The datasets do not record individual activities the tracked animals are performing, however research exists looking into translating movement rates into likely activity states. Taking movement rates, locations and previous behaviours, estimates can be made about the actions of each animal at a specific time step. Using these techniques our project team plans to build a model based on the activity states in response to recorded conditions.
The model itself is planned to be an agent-based model, taking into account the previous behaviours of each individual agent as well as its herd to govern future behaviour. Such models are extremely difficult to mathematically simulate, and make a lot of assumptions to minimise the complexity of the model. Agent-based models allow for more complex individual behaviour, which is a perfect fit for the problem being investigated.
In my fourth and final year of my degree I will be taking part in a year-long group design project, based on modelling and artificial intelligence. I feel that my work done as a part of this research project will help to equip me for the challenges of this style of research using artificial intelligence techniques.
June 19, 2014
by Charles Saunders
Charlie Saunders: ‘Analysis of blood flow control in the brain’
I’ve just completed my second year in the Acoustical Engineering MEng program. I have a particular interest in Signal Processing, specifically biomedical, so I’m thrilled to be working with David Simpson on the analysis of blood flow project, as part of the SPCG (Signal Processing & Control Group) in the ISVR (Institute of Sound and Vibration Research).
The main project is on the analysis of blood flow in the brain. The aim is to better understand the effect of the constriction and dilation of blood vessels within the brain as a response to blood pressure changes (known as the auto regulatory system), particularly in healthy individuals. It’s a great project to work on as I get to apply my knowledge of signal processing to data which is collected in collaboration with the Southampton General Hospital, as well as learn about the workings of various machines such as ECG’s. Another side project I am working on involves the creation of a program used by medical staff to calibrate a physiotherapy machine designed to measure the strength and mobility of a person’s wrist.
Image: Arm Calibration Program)
My next project will by my third year individual project entitled “A computational tool for the assessment of local 3D strain fields in bone tissue” which is also relevant to biomedical signal processing. I then hope to undertake another research internship in the summer between my 3rd and 4th year, and I will also have a group research project in my 4th year. After I complete my degree, I am hoping to start a Phd. My research placement will provide me with fantastic experience and knowledge which I will be able to apply to all of these, and more in the future.
June 18, 2014
by Ian Dawson via Digital Humanities | Digital Humanities
Taplow House, a housing block within the notorious Aylesbury estate, southeast London, named after Taeppa’s Low, a 7th Century Anglo-Saxon burial mound 29 miles west along the River Thames, this 1960’s housing development, famous for the Channel 4 ident, the one where the camera pans across desolate concrete walkways. The regeneration is underway, a project that will see Taplow House …
June 1, 2014
by Graeme Earl via WSI | WSI
I’ve spoken at a number of events recently about what I see as the potential for joining up MOOCs in order to create shared curricula. I have for example cross-referenced material in the Archaeology of Portus course to Coursera and Brown’s Archaeology’s Dirty Little Secrets course, and to the Coursera and Yale Roman Architecture course. In the coming weeks we …