http://hdl.handle.net/2123/980 2013-05-19T02:53:41Z 2013-05-19T02:53:41Z Marco, Nakarin http://hdl.handle.net/2123/6646 2010-10-18T17:29:40Z 2010-10-18T00:00:00Z

Title: Sydney Coastal Waters Chlorophyll 2009 Authors: Marco, Nakarin Abstract: Samples of surface ocean water off shore of Sydney, Australia were collected and nourished with nutrients. The samples were exposed to natural sunlight and kept in a water bath. The variation of chlorophyll as detected by a fluorometer was recorded once per day. The sea water collected was nourished in the manner reported by Harrison (2007). The measurement of fluorescence is reported in Appendix A. The temperature was near 20 degree C.

2010-10-18T00:00:00Z Blair, David G http://hdl.handle.net/2123/5414 2009-09-23T12:22:31Z 2009-09-23T02:46:54Z

Title: Underwater Acoustic Imaging: Exact Geometric-Acoustics Treatment of the Image due to a Specular Reflector Authors: Blair, David G Abstract: In underwater acoustic imaging, used to produce high-resolution images in turbid waters, a specular reflector in general produces a 'pseudoimage' of the receiving array, located on the reflecting surface; the pseudoimage is of considerable use since it reveals the shape of the surface. A system is considered in which a spherical transmitter together with a 2D receiving array give a 3D image in a single 'ping'. A treatment predicting the shape of the pseudoimage - in particular, its lateral extent - is given that is exact within geometrical acoustics. The surfaces to which the treatment is applied are the paraboloid (with two principal radii of curvature) - provided that the transmitter lies on the paraboloid's axis - the sphere, the cylinder and the plane. The treatment involves a ray-tracing algorithm based on the equation of the surface, and an algorithm to invert that procedure using the Levenberg-Marquardt method. Pseudoimages of lines in the array are graphed and discussed, along with, more interestingly, pseudoimages of squares. While the latter pseudoimages are parallelograms when the square is small, in general they are not parallelograms, since all four sides are curved. Further features found are that an 'object' in the array may produce multiple pseudoimages, no pseudoimage, 'local optima' and/or 'blockage points'. Such an exact determination of the resulting pseudoimage for selected surfaces gives useful insight into pseudoimages that occur in practice. Conditions of validity (arising because wave effects are neglected) are given. The report also contains a preliminary discussion of the extension that would be needed to include wave effects. In addition it is shown that, subject to more restrictive conditions, the results apply also to a general smooth surface. A 'paraxial' approximation (similar to the 'large-range approximation' of an earlier paper but somewhat more general) is described and found to be useful.

2009-09-23T02:46:54Z Judd, Bruce Harrison, Daniel P Jones, Ian S F http://hdl.handle.net/2123/2664 2008-08-04T14:20:33Z 2008-07-01T00:00:00Z

Title: Engineering Ocean Nourishment Authors: Judd, Bruce; Harrison, Daniel P; Jones, Ian S F Abstract: The annual productivity of the ocean is limited by the availability of nutrients. Ocean Nourishment is the concept of purposefully introducing nutrients to the surface ocean to sequester carbon dioxide and increase the sustainable supply of marine protein. The engineering challenges are to inject the nutrients so that they diffuse to an appropriate concentration while being consumed by phytoplankton. Ship based supply of nutrients from onshore manufacture is assumed. Broadcasting granular material onto the surface of the ocean is examined. The depth over which the prills or grains dissolve can be controlled by the diameter and density of the particles. Design considerations are discussed.

2008-07-01T00:00:00Z Danoun, Rashad http://hdl.handle.net/2123/1897 2008-06-17T13:10:58Z 2007-07-31T05:20:35Z

Title: Desalination plants: Potential impacts of brine discharge on marine life Authors: Danoun, Rashad Abstract: Water has always been the earth's most valuable natural resource for human beings and ecosystems. Fresh water is an essential natural resource that supports human beings, flora and fauna habitat. Reductions in water quality and quantity have serious negative impacts on ecosystems. Over the past several decades, a tremendous growth in human populations and industrial activities has resulted in a significant demand for fresh and clean water. To meet these challenges and meet the pressures of demand it is critical to find a new alternative of water resource as the natural water resources have almost vanished. In spite of the high cost of desalinated water, an important quanity is already produced to meet the necessity for fresh water worldwide. Desalination could hold the key for new fresh water resources. Building more dams with significant sizable catchments would be a great solution in regards to supplying Australia with fresh water; however, many regions in Australia are facing a reduction in the rainfall and level of runoff. All the dams around Australia face a vast reduction in the storage level due to the diminishment of the inflow rate and the growth in water usage. Some arguments will be raised against building desalination plants on the grounds of environmental impacts to the surrounding area, especially to marine life due to the high concentrated brine discharge that diffuses back into the ocean. The impacts of the brine discharge are due to the high level of salinity and total alkalinity and alteration to the temperature. These impacts could be considerable in terms of the influence on the marine organisms such as the development of species, survival of larva and breeding and reproductive traits. However this paper provides some evidence that the influence of discharge for sesalination plant can be neglected in term of any environmental impact to the aquatic flora and fauna species.

2007-07-31T05:20:35Z Roberts, James Oliver http://hdl.handle.net/2123/1863 2008-06-17T13:06:55Z 2007-07-11T04:35:24Z

Title: Sediment Concentration Measurement Authors: Roberts, James Oliver Abstract: Sydney Harbour is an important port and receational region for the City of Sydney. A study of water clarity is reported here. Water turbidity is influenced by the urban and industrial wastes that drain from the watershed and the flushing of the estuary by clear oceanic water. In order to contrast the imaging of objects underwater by light or sound, it is necessary to understand the role played by the scatterers in the water that cause turbidity. Using five reference sites, the grain size, the number of grains per litre and the turbidity have been compared before and after rain. Three Sydney area estuaries hve been observed to have similar turbidity increases with increasing distance from the sea.

2007-07-11T04:35:24Z Jones, Ian S F Altarawneh, Mohammednoor http://hdl.handle.net/2123/1422 2007-01-29T22:04:13Z 2005-05-02T00:00:00Z

Title: The Economics of CO2 Sequestration Scenarios Using Ocean Nourishment Authors: Jones, Ian S F; Altarawneh, Mohammednoor Abstract: With the aid of a dynamic, general equilibrium model of the global economy, the optimum economic path of carbon dioxide abatement in the atmosphere can be predicted. The “optimum” sequestration path is defined as that which minimizes the economic damage caused by climate change while costing no more than the economic benefits. The prediction depends strongly on the magnitude of the assumed economic damage as a result of climate change. Ocean Nourishment is the purposeful introduction of nutrients into the ocean to sequester atmospheric carbon dioxide and increase the sustainable fish stocks. The feed stock today is natural gas but in the future could be coal. It has been found that carbon credits could be offered to the carbon market at price less $25 (1995 US $) /tonne CO2 avoided, allowing for a typical return on capital and assuming coal prices are stable (in current dollars). The potential of Ocean Nourishment generated carbon credit has been compared with the optimal trajectory carbon tax calculated from different energy models that ignore Ocean Nourishment. This comparison has been done for two emission reduction scenarios, optimum sequestration and Kyoto forever. Following the optimum sequestration path as predicted by the DICE economic model requires about 100 Ocean Nourishment plants to be constructed each decade assuming each plant sequesters 10 Mt of carbon dioxide per year in the ocean. Sensitivity studies show that the number of Ocean Nourishment plants is proportional to the magnitude of the climate change damage function. The Ocean Nourishment option has benefit-cost ratio of 2.75 compared with 1.0 (by definition) of the optimum sequestration. Climate damage to the economy is most severe in the Low Income countries and the economic model has been used to estimate the future cost in this group of countries. Assuming that their population is predetermined, the accumulated economic advantage of mitigating the climate change is $6.2 trillion (1995 US $) accumulated by 2100. The total cost of Ocean Nourishment, is estimated to be $2.5 trillion (1995 US $). The potential of Ocean Nourishment to meet the Kyoto protocol net emissions has also been studied. It has been found that in order to implement a Kyoto forever scenario, about of 150 Ocean Nourishment plants are needed with a total cost much less than the current alternative abatement strategies. Description: 4th Annual conference on Carbon Capture & Sequestration - Developing Potential Paths Forward Based on the Knowledge, Science and Experience to Date.

2005-05-02T00:00:00Z http://hdl.handle.net/2123/1420 2007-01-29T22:06:05Z 2007-01-22T22:53:34Z

Title: Australian-Chinese Ocean Science & Technology - The Proceedings Description: This collection of papers represents The Proceedings of meeting held at the University of Sydney and Australian Academy of Science 15-18 November 2005.

2007-01-22T22:53:34Z Blair, David G http://hdl.handle.net/2123/1086 2008-06-17T12:17:04Z 2006-01-01T00:00:00Z

Title: Underwater acoustic imaging: image due to a specular reflector in the geometrical-acoustics limit. Authors: Blair, David G Abstract: In underwater acoustic imaging, used to produce high-quality images in turbid waters, a specular reflector can produce a 'pseudoimage' of the receiving array at the reflecting surface. Based on the 'geometrical approximation' (similar to geometrical acoustics), formulae are derived for the size and shape of the pseudoimage for both flat and curved reflectors. For curved reflectors, described by two principal radii of curvature, the formulae assume also the 'large-range approximation'. The formulae enable radii of curvature to be determined from an image. Also discussed briefly are possible extensions and the role of non-geometrical effects. Description: Copyright: The Japan Society of Naval Architects and Ocean Engineers. The original publication is available at springerlink.com and directly at http://dx.doi.org/10.1007/s00773-005-0208-z

2006-01-01T00:00:00Z Blair, David G Jones, Ian S F Madry, Andrew http://hdl.handle.net/2123/1070 2008-06-17T12:17:04Z 2006-08-17T05:28:57Z

Title: Underwater Acoustic Imaging: One-bit Digitisation Authors: Blair, David G; Jones, Ian S F; Madry, Andrew Abstract: In underwater acoustic imaging (UAI), the combination of a two-dimensional (2-D) array and replicate correlation can produce 3-D images, typically of objects at a range of 2 m. A system already developed achieves the high data acquisition rate needed through one-bit sampling (sensing only the sign of the received signal). Noise added before the one-bit sampling avoids the production of 'ghosts' in the image. By simulation and mathematical analysis, the effects of one-bit and added noise are studied for a chirp signal, with a restriction so far to 1-D images (image amplitude versus range). Conditions are given for the avoidance of ghosts and the minimisation of 'image noise' - noise in the image due to one-bit and added noise. A model of image noise is proposed, which is corroborated by the tests carried out to date. A general formula for the root-mean-square image noise is obtained. It has previously been suggested that filtering the singal after sampling would improve the image. However, it is shown that filtering is unnecessary and indeed makes the image worse. It is shown that a strong target can suppress evidence of a weak target because, when the strength of the return signal is raised, essentially the amplitude of the added noise must be raised to avoid 'ghosts'. A general formula, giving the ratio of target strengths such that the weak target has a 50% probability of detection, is obtained.

2006-08-17T05:28:57Z Jones, Ian S F Lu, Chien Hsing http://hdl.handle.net/2123/986 2008-06-17T12:04:31Z 2003-05-01T00:00:00Z

Title: Engineering Carbon Sequestration in the Ocean Authors: Jones, Ian S F; Lu, Chien Hsing

2003-05-01T00:00:00Z