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105 results on '"Sweatman, Winston L."'

2. Measurements of Transit Timing Variations for WASP-5b

Author

Fukui, Akihiko, Narita, Norio, Tristram, Paul J., Sumi, Takahiro, Abe, Fumio, Itow, Yoshitaka, Sullivan, Denis J., Bond, Ian A., Hirano, Teruyuki, Tamura, Motohide, Bennett, David P., Furusawa, Kei, Hayashi, Fumiya, Hearnshaw, John B., Hosaka, Shun, Kamiya, Koki, Kobara, Shuhei, Korpela, Aarno, Kilmartin, Pam M., Lin, Wei, Ling, Cho Hong, Makita, Shota, Masuda, Kimiaki, Matsubara, Yutaka, Miyake, Noriyuki, Muraki, Yasushi, Nagaya, Maiko, Nishimoto, Kenta, Ohnishi, Kouji, Omori, Kengo, Perrott, Yvette, Rattenbury, Nicholas, Saito, Toshiharu, Skuljan, Ljiljana, Suzuki, Daisuke, Sweatman, Winston L., and Wada, Kohei

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

We have observed 7 new transits of the `hot Jupiter' WASP-5b using a 61 cm telescope located in New Zealand, in order to search for transit timing variations (TTVs) which can be induced by additional bodies existing in the system. When combined with other available photometric and radial velocity (RV) data, we find that its transit timings do not match a linear ephemeris; the best fit \chi^2 values is 32.2 with 9 degrees of freedom which corresponds to a confidence level of 99.982 % or 3.7 \sigma. This result indicates that excess variations of transit timings has been observed, due either to unknown systematic effects or possibly to real TTVs. The TTV amplitude is as large as 50 s, and if this is real, it cannot be explained by other effects than that due to an additional body or bodies. From the RV data, we put an upper limit on the RV amplitude caused by the possible secondary body (planet) as 21 m s^{-1}, which corresponds to its mass of 22-70 M_{Earth} over the orbital period ratio of the two planets from 0.2 to 5.0. From the TTVs data, using the numerical simulations, we place more stringent limits down to 2 M_{Earth} near 1:2 and 2:1 mean motion resonances (MMRs) with WASP-5b at the 3 \sigma level, assuming that the two planets are co-planer. We also put an upper limit on excess of Trojan mass as 43 M_{Earth} (3 \sigma) using both RV and photometric data. We also find that if the possible secondary planet has non- or a small eccentricity, its orbit would likely be near low-order MMRs. Further follow-up photometric and spectroscopic observations will be required to confirm the reality of the TTV signal, and results such as these will provide important information for the migration mechanisms of planetary systems., Comment: accepted for publication in PASJ, 30 pages, 8 figures, 8 tables

Published
2010
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3. Significant shifts in latitudinal optima of North American birds.

Author

Mateus Martins, Paulo, Anderson, Marti J., Sweatman, Winston L., and Punnett, Andrew J.

Subjects
GLOBAL warming, CLIMATE change, HABITAT selection, SPECIES distribution
Abstract

Changes in climate can alter environmental conditions faster than most species can adapt. A prediction under a warming climate is that species will shift their distributions poleward through time. While many studies focus on range shifts, latitudinal shifts in species' optima can occur without detectable changes in their range. We quantified shifts in latitudinal optima for 209 North American bird species over the last 55 y. The latitudinal optimum (m) for each species in each year was estimated using a bespoke flexible non-linear zero-inflated model of abundance vs. latitude, and the annual shift in m through time was quantified. One-third (70) of the bird species showed a significant shift in their optimum. Overall, mean peak abundances of North American birds have shifted northward, on average, at a rate of 1.5 km per year (±0.58 SE), corresponding to a total distance moved of 82.5 km (±31.9 SE) over the last 55 y. Stronger poleward shifts at the continental scale were linked to key species' traits, including thermal optimum, habitat specialization, and territoriality. Shifts in the western region were larger and less variable than in the eastern region, and they were linked to species' thermal optimum, habitat density preference, and habitat specialization. Individual species' latitudinal shifts were most strongly linked to their estimated thermal optimum, clearly indicating a climate-driven response. Displacement of species from their historically optimal realized niches can have dramatic ecological consequences. Effective conservation must consider within-range abundance shifts. Areas currently deemed "optimal" are unlikely to remain so. [ABSTRACT FROM AUTHOR]

Published
2024
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6. A Mathematical Model of the Ripening of Cheddar Cheese

Author

Sweatman, Winston L., Psaltis, Steven, Dargaville, Steven, Fitt, Alistair, Bock, Hans Georg, Series editor, de Hoog, Frank, Series editor, Friedman, Avner, Series editor, Gupta, Arvind, Series editor, Nachbin, André, Series editor, Ozawa, Tohru, Series editor, Pulleyblank, William R., Series editor, Rusten, Torgeir, Series editor, Santosa, Fadil, Series editor, Seo, Jin Keun, Series editor, Tornberg, Anna-Karin, Series editor, Russo, Giovanni, editor, Capasso, Vincenzo, editor, Nicosia, Giuseppe, editor, and Romano, Vittorio, editor

Published
2016
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8. Symmetric Four-Body Problems

Author

Sweatman, Winston L., Cojocaru, Monica G., editor, Kotsireas, Ilias S., editor, Makarov, Roman N., editor, Melnik, Roderick V. N., editor, and Shodiev, Hasan, editor

Published
2015
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11. Pollutant Transport and Its Alleviation in Groundwater Aquifers

Author

Ali, Amjad, Sweatman, Winston L., McKibbin, Robert, Capasso, Vincenzo, Editor-in-chief, Bonilla, Luis L., Series editor, Günther, Michael, Series editor, Mattheij, Robert M.M., Series editor, Neunzert, H, Series editor, Scherzer, Otmar, Series editor, Schilders, Wil, Series editor, Fontes, Magnus, editor, and Marheineke, Nicole, editor

Published
2014
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12. Mathematics-in-Industry Study Group (MISG) Steel Projects from Australia and New Zealand

Author

Sweatman, Winston L., Wakayama, Masato, Editor-in-chief, Anderssen, Robert S., Series editor, Bauschke, Heinz H., Series editor, Broadbridge, Philip, Series editor, Cheng, Jin, Series editor, Chyba, Monique, Series editor, Cottet, Georges-Henri, Series editor, Cuminato, José Alberto, Series editor, Ei, Shin-ichiro, Series editor, Fukumoto, Yasuhide, Series editor, Hosking, Jonathan R. M., Series editor, Jofré, Alejandro, Series editor, Landman, Kerry, Series editor, McKibbin, Robert, Series editor, Mercer, Geoff, Series editor, Pipher, Jill, Series editor, Parmeggiani, Andrea, Series editor, Polthier, Konrad, Series editor, Schilders, Wil, Series editor, Shen, Zuowei, Series editor, Toh, Kim-Chuan, Series editor, Yoshida, Nakahiro, Series editor, Verbitskiy, Evgeny, Series editor, and Takagi, Tsuyoshi, editor

Published
2014
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34. Solutions to the inverse problem in a two-dimensional model for microwave breast tumour detection

Author

Senaratne, G.G., Keam, Richard B., Sweatman, Winston L., and Wake, Graeme C.

Subjects
Breast tumors -- Research, Computers and office automation industries
Abstract

Byline: G.G. Senaratne, Richard B. Keam, Winston L. Sweatman, Graeme C. Wake This paper presents an in vivo detection method to estimate the size and the position of a breast tumour using microwave frequencies. At these frequencies there is a significant difference in dielectric properties between a malignant tumour and healthy breast tissue. By considering these properties we solve the forward problem of the signal's scattering effect for a two-dimensional breast model. We use Newton's multidimensional iterative method to solve the inverse problem and compute the unknown location and size of the tumour. Our analytical study suggests that the approach will be capable of detecting a millimetre size tumour inside the breast. Due to the complex scattering from the non-homogeneous internal structure and other complications the microwave measurements can have errors. However, in tests, our algorithm can calculate tumour distance with 0.54% error when there is a 10% error in the value of the microwave field measurements.

Published
2007

38. A simplified financial transmission rights auction in the context of the New Zealand electricity grid

Author

Pritchard, Geoff, Sweatman, Winston L, Mohammadian, Ghazaleh, Kilby, Philip, Pritchard, Geoff, Sweatman, Winston L, Mohammadian, Ghazaleh, and Kilby, Philip

Abstract

This article considers the use of financial transmission rights for managing electricity provision on a power grid. The use of a subgrid of hubs for dealing in these products is explored. Some suitable approaches to this practice are outlined. These identify the feasible size of sub-grid and locate additional constraints.

Published
2013

43. Measurements of Transit Timing Variations for WASP-5b

Author

Fukui, Akihiko, primary, Narita, Norio, additional, Tristram, Paul J., additional, Sumi, Takahiro, additional, Abe, Fumio, additional, Itow, Yoshitaka, additional, Sullivan, Denis J., additional, Bond, Ian A., additional, Hirano, Teruyuki, additional, Tamura, Motohide, additional, Bennett, David P., additional, Furusawa, Kei, additional, Hayashi, Fumiya, additional, Hearnshaw, John B., additional, Hosaka, Shun, additional, Kamiya, Koki, additional, Kobara, Shuhei, additional, Korpela, Aarno, additional, Kilmartin, Pam M., additional, Lin, Wei, additional, Ling, Cho Hong, additional, Makita, Shota, additional, Masuda, Kimiaki, additional, Matsubara, Yutaka, additional, Miyake, Noriyuki, additional, Muraki, Yasushi, additional, Nagaya, Maiko, additional, Nishimoto, Kenta, additional, Ohnishi, Kouji, additional, Omori, Kengo, additional, Perrott, Yvette, additional, Rattenbury, Nicholas, additional, Saito, Toshiharu, additional, Skuljan, Ljiljana, additional, Suzuki, Daisuke, additional, Sweatman, Winston L., additional, and Wada, Kohei, additional

Published
2011
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47. Fluid flow and solute transport in unevenly-stratified groundwater aquifers.

Author

Ali, Amjad, McKibbin, Robert, and Sweatman, Winston L.

Subjects
FLUID dynamics, GROUNDWATER, POROUS materials, TRANSPORT theory, AQUIFERS, POLLUTANTS, LAYER structure (Solids), DISPERSION (Chemistry)
Abstract

Chemical species such as tracers or dissolved pollutants are dispersed by water flowing within a permeable matrix. The species move not only 'down-stream', but also spread in all directions. The rate of dispersion depends on the porous structure and the fluid speed. The natural layered structure of groundwater aquifers is used to discretize them into 'almost horizontal' layers, where each of them may have different matrix properties such as permeabilities, dispersivities, porosities, etc. The thickness of each layer may be horizontally varying. Steady-state fluid flow is considered here in both confined and phreatic aquifers for illustration. [ABSTRACT FROM AUTHOR]

Published
2012
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48. Full ionization in binary–binary encounters of equal masses with a small positive total energy.

Author

Sweatman, Winston L.

Subjects
*IONIZATION (Atomic physics), *NUCLEAR energy, *NUCLEAR physics, *STARS, *ASTRONOMY
Abstract

Interactions between pairs of binary stars play an important role in the dynamics of dense stellar systems. One possible outcome of a binary–binary encounter is full ionization: the destruction of both interacting binaries resulting in four separating single stars. This process is only possible for positive total energy, and the cross-section for full ionization falls to zero at zero total energy. In the context of a stellar system, full ionization is most likely to involve the interaction of two soft binaries with low binding energies. We consider the case where the four stars have a similar mass and derive an asymptotic power law relating the cross-section for full ionization with the total energy when this latter quantity is small. Our new theory makes use of the fact that the most dramatic changes in scale and energies of a few-body system occur when its components pass near to a central configuration. Numerical simulations are used to verify the result. [ABSTRACT FROM AUTHOR]

Published
2007
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49. Erratum: Measurements of Transit Timing Variations for WASP-5b

Author

Fukui, Akihiko, Narita, Norio, Tristram, Paul J., Sumi, Takahiro, Abe, Fumio, Itow, Yoshitaka, Sullivan, Denis J., Bond, Ian A., Hirano, Teruyuki, Tamura, Motohide, Bennett, David P., Furusawa, Kei, Hayashi, Fumiya, Hearnshaw, John B., Hosaka, Shun, Kamiya, Koki, Kobara, Shuhei, Korpela, Aarno, Kilmartin, Pam M., Lin, Wei, Ling, Cho Hong, Makita, Shota, Masuda, Kimiaki, Matsubara, Yutaka, Miyake, Noriyuki, Muraki, Yasushi, Nagaya, Maiko, Nishimoto, Kenta, Ohnishi, Kouji, Omori, Kengo, Perrott, Yvette, Rattenbury, Nicholas, Saito, Toshiharu, Skuljan, Ljiljana, Suzuki, Daisuke, Sweatman, Winston L., Wada, Kohei, and Collaboration), (The MOA

Published
2011
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50. Pneumatic Conveying

Author

Michael Meylan, Edward Bissaker, Ognjen Orozovic, Fillipe Georgiou, Tomas Marsh, James Hill, Mark McGuinness, Winston Sweatman, Ngamta Thamwattana, Bissaker, Edward J, Orozovic, Ognjen, Meylan, Michael H, Georgiou, Fillipe, Marsh, Tomas J, Hill, James M, McGuinness, Mark J, Sweatman, Winston L, and Thamwattana, Ngamta

Subjects
slug flow, pneumatic conveying, General Medicine
Abstract

Pneumatic conveying is the transportation of bulk solids in enclosed pipelines via a carrier gas, typically air. The local flow pattern in a pipeline is a function of the conditions, and slug flow can form under certain conditions. Slug flow is a naturally occurring, wave-like flow where the bulk material travels along the pipeline in distinct `slugs'. Establishing the environment for the formation of slugs within the conveying system is essential to maximise the overall system efficiency and minimise damage to the bulk material. MISG2021 considered a wide range of mathematical approaches to slug formation and travel. These two key problem areas have the most significant potential to impact the system design and efficiency. Critical interconnected facets of pneumatic conveying systems were investigated and an overview for future work was developed. Many of the avenues uncovered during the MISG2021 require more time for in-depth analysis. This analysis and framework will aid in optimising conveying system design and provide insight to construct more efficient pneumatic conveying systems. Refereed/Peer-reviewed

Published
2023

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