Project Stakeholders: Dr N Stocks and I shall be involved in the project, with guidance on apparatus set up from Huw Edwards.
Project Specification: This project is an experimental study into the effects of granular clustering, when a horizontal force (of constant magnitude) is induced onto a binary mixture of ‘spherical’ granules at a constant frequency. It is a development on two previous third year projects (by L. Muttitt and J Martin). The research shall supplement the work of Mullin and Reis.
From previous experimentation we can tell that two forms of granules, of different sizes (e.g. poppy seeds and ‘100s and 1000s’), that are mixed together uniformly can form regular stripe patterns, perpendicular to the direction of force they are exposed to, when subjected to a ‘side-to-side’ motion. This project will expand on these results by investigating the possibility of particles set up in clustered pattern at initial stages of the experiment dispersing and reconvening to the same stripe formation witnessed in earlier experiments. Or do they prefer to remain in their clustered group positions, despite being shaken?
If a ‘regular’ stripe of granules A (poppy seeds), surrounded by granules B (“100s and 1000s”), is positioned such that it is not perpendicular to the direction of motion of the shaking table, do the particles reposition themselves such that they are 90-degrees from the direction of subjected forces? Or do they disperse themselves randomly among one another, possibly later forming such patterns? From this one could consider the possibility of deducing a critical angle particles could be aligned to before they are encouraged to disperse uniformly across the surface available to them, by the sideways movement exerted on them.
Project Methodology: This is largely an experimental and analysis of results study. It will involve using apparatus owned by the University of Warwick, in the form of a test rig which was assembled by a previous student. The test rig shall consist of a rectangular tray (of length 400mm, width 200mm and height 40mm) connected to a vibrator. This vibrator is powered from an electric source, through an amplifier. This amplifier is used to control the amplitude and frequency of movements induced on the tray by the vibrator.
As stated in ‘Project Specification’, the granules being tested shall be arranged in a number of ‘patterns’ from which one can investigate their dispersion and clustering. A transparent cover supporting a reference grid and protractor shall be placed above the testing rig to note changes in granular positioning. Particle movements shall be recorded on film and also captured in still photographs, taken at set time intervals throughout the experiment (interval suggestion: 5 min, 10 min, 15 min, 30 min, 1 h, and 6 h after the vibrations begin).
Project Resources: The apparatus one shall require to for fill this investigation have been referenced to in the above sections of this plan, in summary:
Previously constructed test rig (including rectangular tray and vibrator)
Electrical connection cables (to connect rig vibrator to mains supply)
Transparent tray cover (with reference grid and protractor)
Digital camera (able to capture stills and record real time)
“100s and 1000s”
A safe working area of 2m2 is required to set up and use apparatus, being careful that electrical cables do not obstruct the working environment in a hazardous way (e.g. where they could become trapped in the test rig whilst in motion, come into contact with water or cause someone to trip over them).
Aid from Hugh Edwards shall be necessary in initially guiding me through the apparatus set up, showing me how to level the tray surface and connect the amplifier to the vibrator correctly etc.
In terms of literature, the following sources will be of use:
Duran J, Powders Sands and Grains, 2000, Springer, 2nd Edition
Martin J, Further Investigations into Granular Segregation, 2005, University of Warwick
Muttitt L, Further Investigations into Granular Clustering, 2001, University of Warwick
Mullin T, Coarsening of Self-Organized Clusters in Binary Mixtures of Particles, Physical Review Letters, Volume 84, Number 20, 2002
Mullin T and Reis P M, Granular Segregation as a Critical Phenomenon, Physical Review Letters, Volume 89, Number 24, 2002
Hsiau S S and Yu H Y, Segregation Phenomenon in a Shaker, Powder Technology, Volume 93, 1997
Hill K M, Caprihan A and Kakalios J, Bulk Segregation in Rotated Granular Material Measured by Magnetic Resonance Imaging, Physical Review Letters, Volume 78, Number 1, 1997
Werner B T, and Hallet B, Numerical Simulation of Self-Organised Stone Stripes, Nature, Volume 361, 1993
Koeppe J P, Enz M and Kakalios J, Phase Diagram or Avalanche Stratification of Granular Media, Physics Review E, 1997
Rosato A, Why the Brazil Nuts are on Top, Physics Review Letters, Volume 58, Number 10, 1987
Vanel L, Rosato A D and Dave R N, Rise-Time Regimes of a Large Sphere in Vibrated Bulk Solids, Physical Review Letters, Volume 78, Number 7, 1997.
Term 1: Project specification to be submitted by Friday of week 3. By Friday of week 5 a workshop plan should be submitted. Meet with Hugh to discuss how to set up the apparatus and have read through previous projects to see how I can expand on previous research. Pull out some reading from the list above and negotiated my way around texts that will be beneficial to future write ups and give me a broader knowledge of topic specifics. Begin the experimental applications of this project, and identify any limitations or problems that I am likely to occur through out the project, and hopefully avoid. I intend to set aside Thursdays to focus on my project, meeting with Dr Stocks at some point during the day to talk about my project.
Term 2: Friday of week 15 a second workshop plan should be submitted. By this point, supervision on apparatus set up from Hugh should be unnecessary. This term will be spent focusing mainly on collecting results through practical experimentation, keeping an up to date lab log of any concerns with the project and further options to investigate that I may have come across. I intend to set aside Wednesday afternoons and some hours on Fridays to focus on this project. I hope to continue meeting with Dr Stocks for half hour sessions to discuss my project, weekly.
Term 3: By week 21 a report must be produced, that includes a two-page summary of your progress together with a literature review. In week 22 an oral presentation shall be given outlining my progress and plans for future work. I expect lab work to be less frequent during the build up toward exams, but will have a couple of weeks at the end of term with no lectures in which to focus on the project and begin constructing my final report. I hope that work I will have achieved throughout the rest of the year will set me in a good position at this point in the year.
Over the summer: I intend to have a drafted report complete, which I can make adjustments to at the beginning of the year having spoken to Dr Stocks. This will involve taking books away with me to fully comprehend the analysis of results.
This project involves the use of electrical equipment. It is therefore important that the apparatus is not in contact with water and that any wiring is not obstructing the area in which working, such that it could be tripped over or caught on. All electrical equipment should have been tested by the university with regard to safety and have a sticker with the test reference and date taken stamped on it, it is important to check for this before starting work.
The test rig also involves mobile equipment. One should keep hands well away from moving equipment during the experiment, so as not to trap fingers or clothing in the mechanism possibly resulting in injury.
Poppy seeds and ‘100s and 1000s’ are used in this model. It is important to keep these carefully stored in a beaker when not in the tray of the test rig. Should they scatter on the floor they could be hazardous to those walking near by, causing them to slip and again could result in injury.
It is important, as with any experimental lab procedure to follow a set of general lab rules. The following insert was taken from
(12th October 2006)“HOW SHOULD I CONDUCT MYSELF? Ÿ When in the presence of powered test machinery or when working with hazardous, heavy or hot materials: Ø Do not work alone in the lab. Ø Do not wear bulky, loose or trailing clothes. Ø Use appropriate protective equipment—gloves, safety glasses, aprons, and face shields. Never wear contacts when working with volatile materials. Ø Always wear shoes that completely cover your feet and pants that completely cover your legs. Ø Tie back long hair. Remove metal bracelets or watch straps when working with electricity. Ø Never lift objects that are heavier than you can safely handle. Always use appropriate mechanical means for lifting, carrying, positioning or adjusting heavy equipment or supplies. · Place all belongings out of the work area. · Do not obstruct doorways. · Do not play in the lab. · Never eat, drink, or smoke in a lab. Never taste or smell chemicals. · Always wash your hands before leaving the lab. · Know the location of and how to use the safety equipment. · Know the hazards of the chemicals you are using. Use the Material Safety Data Sheets (MSDS) provided in the lab or at http://ehs.siue.edu. · Dry wet hands and clothing before working with electricity. Mop up all water spilled on the floor. · Keep the lab clean. · Treat all equipment with care. · Be as careful for the safety of others as for yourself. Think before you act.”
Finally, computers are likely to be used in the write up of this project. It is important to note that working at a computer for several hours at a time can cause possible eye strain. It is important to minimise the amount of hours one spends at the computer, at any one time.
It is possible to prevent the above hazards by:
- wearing full lab protection
- keeping hair tied back
- wearing no loose jewellery
- not leaving power supply on
- not leaving equipment unattended
- not leaving cables trailing on the ground
- not using computer equipment from prolonged periods of time