Sub-Explorer
I came up with the idea to build a small submarine after researching the internet and discovering the problems in which divers had to face in dangerous and time consuming tasks. The Remotely Operated Vessel (ROV) was designed to perform hull inspections on boats to look for hull damage and leakage of contaminates such as oil or other chemicals into the water. Search, rescue and recovery, are also common tasks which need to be carried out by the police when searching for objects and items. The ROV has been constructed at a reasonably low cost for submersing in depths down to 10 metres. It is remotely operated therefore needing a tether cable to link up between the computer and the vessel. I built a computer case-top from parts that I already had to eliminate the need for an expensive laptop. A program that I wrote in QBASIC interprets input data from the operator and sends out signals to the various operations on the vessel such as to dive, surface, propel, etc. The entire project consisted of five individual technology processes. Key processes such as Propulsion, Maneuverability, Dive & Surface capability, Imaging system, and the Control system. Each process required a cost effective and practical solution but still needing to function efficiently and be low maintenance. Through continuous testing and trial & error I feel I came up with the best possible solutions with the limited amount of time and money I had to spend. I wouldn’t have got as far as I have without the help and support from friends, family and local businesses. They helped with ideas and advice from time to time, help with funding, and the sponsorship of materials and tools. Now that the ROV is complete, I have been able to trial and test it in a swimming pool. Apart from discovering a few minor leaks in the hull and ‘bugs’ in the computer program, I was able to witness the success of the vessel under operation and find any improvements that could be done to make it work better in future. With further more tests at greater depths the ROV will soon be at the stage where it can perform hull inspections of boats and find lost objects and items underwater. I feel it has the opportunity to be a marketable device to underwater industries all over the world.
The Levitating Ball
This project was inspired by a tournament call the International Young Physicist’ Tournament (IYPT). The problem could be broken into two aims: ‘Investigate the forces that cause a ball to levitate in a titled airstream’ and ‘optimize the system for the maximum angle of tilt that results in a supported ball’. The first stage of the investigation was research and learning. Two fluid mechanics courses online were used to build a basic of knowledge of the subject. Next a force diagram was created to model the forces acting on the ball. The diagram identified a force called the lift force that must be acting on the ball to be supported. There were three contending theories that could explain the lift force: The Bernoulli theory, the Coanda theory and the Magnus theory. A practical investigation was then instigated to differentiate between these three theories. Since the Magnus theory is only applicable if the ball is spinning in the airstream, this theory was isolated by changing the center of mass of the ball but keep everything else constant (this allowed control of how much the ball spun in the airstream). Changing the center of mass didn’t impact on the maximum angle of tilt at all, proving that the spinning of the ball isn’t producing a significant amount of lift, and therefore the Magnus theory couldn’t be a cause for lift. Because further testing couldn’t isolate the Coanda and Bernoulli theories, a solution was developed to explain why the two remaining theories might co-exist. Further testing methods have been designed to investigate this possibility in more depth. To meet the second aim of this project, an investigation was launched to see how parameters affected the maximum angle that the ball could be supported at. The parameters investigated were: Ball radius, ball mass, ball surface, air speed and airstream diameter. A lot of time was spent creating a reliable experimental method. The method could be used to support a ball in an air stream, slowly tilt the air stream, and then measure the angle of tilt the moment that the ball fell out. After experimentation, a table was created to describe how the listed parameters affect the maximum angle of tilt that a ball can be supported at. Explanations were proposed for why each parameter affected this angle. Future experiments have been devised to build a deeper understanding of the effects of a wider range of parameters.
Totarol
Research Question: To what extent does totarol show antibiotic potency against significant strains of Staphylococcus aureus causing skin and soft tissue infections in New Zealand, compared with commonly prescribed drugs used to treat the specific strain of Staphylococcus aureus being tested? Purpose of research: This essay will investigate the antibacterial potency of totarol against significant strains of Staphylococcus aureus (S.aureus) causing skin and soft tissue infections (SSTIs) in New Zealand. Only a small amount of research on totarol has been conducted. They all suggest totarol possesses antibiotic potency against various species of bacteria. The mode of action of totarol is currently unknown. Procedure 1: The totarol I ordered from Mende Biotech Ltd arrived in two forms; a powder called Totarol™ and a viscous brown liquid called Liquid K7 (LK7) in which the Totarol™ powder was dissolved in mostly sunflower oil. The investigation took place in two stages. In the first stage, the MIC value of the LK7 against reference strain S.aureus 29213 was determined by following the CLSI methodology for MIC testing (M07-A9 Clinical and Laboratory Standards institute). The MIC test was also conducted to identify whether any major ingredients in the LK7 possessed significant antibacterial potency. MIC values where compared with that of flucloxacillin. Data from stage 1 testing: LK7 had an MIC value of 1µg/mL, which was very similar to flucloxacillin’s MIC value of 0.5µg/mL. No other major ingredients in LK7 showed antibacterial potency. Totarol™’s antibacterial activity could not be accurately measured, due to the powder resisting even mixing. Procedure 2: In the second stage, disc diffusion tests were conducted against various S.aureus clinical isolates obtained from SSTIs in the Waikato community. The discs that were placed for each clinical isolate included LK7, cefoxitin, fusidic acid, mupirocin and erythromycin discs. Data from stage 2: 75% of LK7 discs produced double zones of inhibition. I hypothesized that this was due to two active ingredients found in the LK7. I predicted the one that produced larger zones of inhibition to be Totarol™. The other more stable ingredient producing the inner zones of inhibition is unknown. Conclusion: I proposed a breakpoint of outer zone sizes that were ≥ 15 mm in diameter to signify that that particular clinical isolate was ‘susceptible’ to LK7. From this breakpoint, LK7 and fusidic acid both had the same number of clinical isolates that were classified as ‘susceptible’. LK7 was the median of the number of susceptible clinical isolates. This data answered my research question; totarol in the LK7 form specifically, would be just as effective in treating SSTIs caused by S.aureus, as even the most commonly prescribed antistaphylococcal drugs currently being used.
Fig Preservation
Figs have become an expanding industry here in New Zealand and are a current export fruit which could potentially provide a large amount of profit to both growers and the New Zealand market as a whole. Nicola’s family has about 10 acres of fig trees. They sell the figs locally and as an export. They generally sell for about $13 per kilogram here in New Zealand and $26 in the USA. However, figs only have a shelf life of about 7 days. This is because at present there is no proven pre or post-harvest treatment or method of storage that helps to decrease the rate of decay of the fig fruit. After researching post-harvest treatments for figs, Nicola found a report which claimed to have developed treatments that increased the shelf life of figs by about 5 weeks. With this kind of increase, it would be possible to transport, store and export figs over longer periods of time without running the risk of losing large amounts of produce, or delivering unsatisfactory fruit to customers. Nicola developed 7 different post-harvest treatments based on the ones that had shown promise in earlier research. These were hot-water baths of different temperatures, both with and without different bleach concentrations. To test these on the fruit she set up four experiments – a dry matter test, a firmness test (using a penetrometer), a colour test and observation of detrimental features of the fig. She tested these treatments at 0, 7, 14, 21 and 28 days from harvest. Nicola found that after 7 days, the firmness of all of the figs that had been treated had decreased to a large degree. The only figs that did not have a massive decrease were the untreated fruit. However after about 14 days, the firmness of all of the fruit became about the same and after this 14 day mark, she would not have considered any of the figs to be edible. However, in the appearance tests, it seemed that the treated figs that had the least amount of mould and rot were the ones that had been treated with higher levels of bleach such as the 55 degree Celsius water bath with 0.003L of bleach to every litre of water, and the 35 degree Celsius water bath with the same concentration of bleach. Overall, Nicola’s results showed that the hot water bath, and hot water bath and bleach post-harvest treatments did not slow the decay of the fruit in the earlier weeks after picking. In effect, Nicola’s research showed that the information she had relied on to help plan her study had claimed too much and that the treatments were less effective than had been stated. More research will be needed to find a more reliable way to improve the shelf life of figs.
Gannet Investigation: Survivng an Unnatural Disaster
For a unique marine bird, so magnificent and accessible to the public, the Australasian Gannet (Morus serrator) colony found at Cape Kidnappers, 紐西蘭, significantly lacks research. Knowledge of gannet behaviour and how humans could best sustain a relationship with them remains unstudied. M. serrator are colonial monogamous breeders and produce a single chick each breeding season (Ismar, S.M.H. 2013). With the same mate over breeding seasons, pairs work cooperatively sharing the energy input into a single chick. Such parental care leads to highly territorial behaviour (McMeekan, C. P. & Wodzicki, K. A. 1946). This suggests more dominant gannets would claim larger territories to have a greater distance between nests of other birds, to increase the survival of their offspring. With a land-based colony this means the gannets are at risk from land and airborne predators, suggesting more dominant birds will claim territories in the central area as it offers greater safety from predator pressures (Minias, P. 2014). It was hypothesised that birds in the centre will have a greater distance between their nests and have a smaller height compared to those around the periphery of the Plateau Colony. The distances between nests and the heights of nests were recorded in the centre and around the periphery of the colony to determine if there was a correlation between the variables. It was found that centre nests had a greater distance between them and were of a smaller nest height when compared to those around the periphery. Anthropogenic influences from tourism and conservation has the potential to change the evolutionary trajectory of managed populations. This colony is protected by predator control programs. Altering this significant selection pressure has the potential to change the nesting behaviour of this species. Monitoring annual nesting distribution patterns and colony numbers over time, may enable informed development of more sustainable ecotourism and protection of the colony. This investigation provides baseline data to support further research on this colony.
How to spill your coffee
We all do it – walk along with a cup in hand, and carelessly spill it. While it’s usually more annoying than anything else, it happens to affect almost all of us, and little is done to minimise the likelihood of it occurring. So my aim was to explain the physics behind why we spill drinks when we walk, and to investigate how we can minimise the likelihood of this occurring. I broke this investigation into two distinct parts, explaining the system of the cup, and explaining the effect of walking. From initial observations, it was clear that the cup was a resonating system. Like any resonating system, the cup has a natural frequency. When the cup is oscillated – moved back and forth – at near this frequency, the size of the liquid oscillations is very large. This is because the acceleration is in phase with the motion of the liquid, so in each cycle maximum energy is input into the system. In my investigation I experimentally measured this natural frequency, and created a mathematical model to explain this frequency. It was also found that as the size of liquid oscillations in the cup increases, so does distortion of the fluid surface, possibly enabling spilling. To systematically analyse the effect of walking, I had subjects walk on a treadmill, so walking surface and speed were controlled. However, I also needed an accurate way of measuring the motion of a carried cup. Firstly, I tried to use video analysis; however I found this far too imprecise for measuring small changes in velocity of a cup. In the end I used a smartphone to record the acceleration of a carried cup, as acceleration is what causes the movement of liquid in a cup. This allowed surprisingly accurate measurements to be made, and allowed both the size and frequency of the acceleration to be recorded. In order to relate the system of the cup and the oscillation provided whilst walking I conducted a qualitative experiment into the effect of stride frequency on the likelihood of spilling. When stride frequency was very close to the natural frequency of the cup, spilling occurred almost instantly, while it did not occur if stride frequency was much higher or lower. In the end, my research showed that to minimise the likelihood of spilling your drink walk slowly, use a narrow cup, focus on walking smoothly, and fill the cup well below the rim. Despite this, some people happen to be much smoother cup carriers than others, likely due to their individual biomechanics. And, if you really don’t want to spill your drink, you can always use a lid.
VERMICOMPOSTING-EFFICIENT DAIRY SLUDGE MANAGEMENT
The continued growth of dairy farming in NZ and the move toward keeping cows on stand-off pads has seen a major increase in two significant waste streams, the wood fibre that is scrapped off the surface of the standing pads and the effluent that is now concentrated at the site of these pads. In combination these waste streams offer the farmer an opportunity to recycle valuable nutrients back into the soil as an up-valued soil conditioner. This investigation explores vermicomposting as a tool to efficiently manage these two significant waste streams. Sludge was removed from a settling pond and mixed with a range of carbon products that are recommended by Dairy NZ for use in stand-off pads: wood chips, post peeling, sawdust and also wood shavings (used in calf sheds). The wood fibre/sludge mixtures were assessed on their acceptability to tiger worms (Eisenia fetida) by measuring the pH of the mixture and seeing if they corresponded with the preferred pH for tiger worms. The vertical spatial distribution of tiger worms was measured over a period of 15 days and the rate at which the worms moved into the different mixtures was assessed. The worm mass before and after this 15 day period was also measured to ascertain the mixtures’ ability to support worm growth. Finally, different ratios of sludge and post peelings removed from a calf shed were used in a choice chamber experiment to establish the worms’ preference. Tiger worms were used throughout the investigation as they represent the worm species most widely used in vermicomposting in New Zealand. Tiger worms feed on decomposing organic matter, bacteria and fungi in the upper organic horizon of soil. All of the unused wood fibre and dairy sludge tested lay within the acceptable pH range for tiger worms. Wood fibre exposed to large amounts of urine ie calf shed post peelings, that lie outside the acceptable range can be favourably adjusted with the addition of dairy sludge. All the particle sizes of the wood fibre tested were found to be acceptable to tiger worms and capable of supporting increase in their body mass beyond that of the compost. Due to the observation that the worms did not integrate themselves as fully in sawdust as the other fibres tested it is recommended that further investigation should be carried out before sawdust is used for vermicomposting. While a comparison of the average worm density in each mixture may indicate a preference for post peelings this cannot be statistically proven and more trials are recommended. The preferred ratio within the limits that were tested is 1:3 calf shed post peelings to sludge (41% dry weight). Vermicomposting can therefore be recommended as a possible onsite technology to process the twin waste streams of wood fibre and effluent generated by dairy farms. The next step would be to implement medium scale field trials with a continuous windrow system, testing resulting compost for its nutrient content and then comparing this output to that of current practises
Neolema ogloblini- An agent in the biological control of Tradescantia
Tradescantia (Tradescantia fluminensis) is the worst weed in New Zealand. By smothering and shading out seedlings, Tradescantia prevents forest regeneration. Current control methods are ineffective and simultaneously cause harm to native forest. In 2011 Neolema ogloblini, a Brazilian beetle was introduced into New Zealand as a biological control for Tradescantia. To be successful in New Zealand, a country with different environmental factors, the beetles’ ranges of preference (temperature and light intensity) had to be investigated. A gender specific trait also identified, to enable desired sex ratios within founding populations to be selected. [18] This would ensure that the beetles are not released in areas of physiological stress, and can be optimised to have the greatest impact on Tradscantia. To establish how the intensity of light affects the distribution and amount of Tradescantia eaten by N.ogloblini a choice chamber investigation was conducted. Different layers of shade cloth provided a range of light intensities 150-3450Lux (likely to be found under forest canopy where Tradescantia is problematic). Thirty beetles of a range of sizes and approximately same maturity were randomly distributed through the chambers. Each chamber contained a shoot of Tradescantia with 5 leaves. After a 24hour period the number of beetles in each chamber were counted and the amount of surface area of the leaves eaten measured. The effect of temperature on the amount of leaf surface area eaten was investigated by selecting 90 beetles of a range of sizes and withholding food for 24hours. Five beetles were placed in each of three containers containing two leaves. Each trial container was precooled/warmed to the test temperature before the beetles were added. Leaves of a similar size, shape, mass and maturity were used. All leaves were genetically identical and collected from the same location. Sets of three containers were held in the dark at the following temperatures for 24hours: 9°C, 15°C, 20°C, 25°C, 30°C and 35°C. The surface area of leaf eaten at each temperature (mm2) was calculated. Lastly, microscopic dissections were conducted, using 32 beetles ranging in size, to establish if length (measured from the top of the head to the base of the abdomen) could be used as a phenotypic marker to identify beetle gender. While only a very weak positive relationship between increasing light intensity and the number of beetles was found a significantly higher area of leaf was eaten at a light intensity of 3450Lux compared to 150Lux. The amount of leaf area eaten is significantly reduced at temperatures of 15˚C and below, and significantly increased at 35˚C. There is no significant difference in the amount of leaf area eaten when comparing temperatures between 20-30˚C. Females have on average a larger body length (median=4.92mm) than the males (median=4.215mm). Therefore, sites with warmer temperatures in dappled light conditions (3450Lux) should be prioritised for the release of N.ogloblini, as this is the location in New Zealand at which their use as a biological control will be optimised. Beetle length can be confidently used to select desired gender ratios.
Bioplastic - The Future is Degradable Plastics. Investigating Biodegradation of Polyhydroxybutyrate Bioplastic by 紐西蘭 Soil Microorganisms
The rate and production of conventional petroleum based plastics is unsustainable and not eco-friendly. Plastics often end up in marine environments and can take hundreds of years to decompose in landfills. According to Statistica, in 2015 alone, global plastic production was approximately 322 million metric tonnes and is projected to increase in the future. PHB bioplastic or Polyhydroxybutyrate is both biologically produced and biodegradable and can serve as a viable alternative to conventional plastics. But can it be broken down by soil microbes within a reasonable time frame? I have set out to answer this question. My aim was to isolate and analyse microorganisms from the Rotorua area that are capable of degrading Polyhydroxybutyrate (PHB) bioplastic . I isolated PHB degrading microorganisms from Rotorua soils by culturing on an agar based mineral salt media supplemented with PHB powder (MSM PHB agar). Samples were taken from Mount Ngongotaha and Te Puia geothermal soils as well as Okareka, termite frass and termite guts. One isolate from the Te Puia sample (labelled G2) was found to successfully degrade PHB powder. After isolation and purification of the G2 isolate, it was cultured on a range of media types to examine properties exhibited under differing nutrient conditions. Multiple organisms were found to be involved in the degradation of PHB bioplastic and work together symbiotically, this included bacteria and fungi which was identified as penicillium. The sample isolated from Te Puia soils (site 2 – G2Clear) in the Rotorua environment was found capable of competently degrading PHB, clearing 8% of PHB after 26 days. The G2Clear isolate is a mixture of bacteria and fungi working in an endosymbiotic relationship to degrade PHB and are unable to successfully degrade PHB individually. It is through the secretion of an extracellular PHB depolymerase enzyme that PHB is degraded, conforming with my hypothesis. This proves that PHB bioplastic is a viable alternative to conventional petroleum based plastics as PHB can be relatively quickly broken down by soil microorganisms.