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News Article | December 14, 2015
Site: phys.org

In an effort that would put metal fans to shame, the native blue-banded bee has been filmed head banging flowers up to 350 times a second. The technique causes vibrations that release pollen into the air similar to the motion of a salt and pepper shaker, helping pollinate the flower. More than just a biological curiosity, the discovery could open the door to advances in areas ranging from improving the efficiency of certain crop pollination to better understanding muscular stress and the development of miniature flying robots. The joint RMIT, University of Adelaide, Harvard University and University of California, Davis study compared the pollination techniques of Australian native blue banded bees with North American bumblebees, which are commonly used overseas to commercially pollinate tomato plants. While their American counterparts grabbed the anther of the tomato plant flower with their mandibles before tensing their wing muscles to shake the pollen out, super slow motion footage revealed the bee from down under prefers a "hands-free" approach. The research team found that by recording the audio frequency and duration of the bees' buzz, they were able to prove the Aussie bee vibrates the flower at a higher frequency than overseas bees and spend less time per flower. RMIT researcher Dr Sridhar Ravi, from the School of Aerospace, Mechanical and Manufacturing Engineering along with colleagues Callin Switzer (Harvard) and bee specialist Dr Katja Hogendoorn (School of Agriculture, Food and Wine, University of Adelaide), said it was the first time the phenomenon had been observed. "We were absolutely surprised. We were so buried in the science of it, we never thought about something like this. This is something totally new," he said. With bumblebees not found on the Australian mainland, local greenhouse tomatoes are pollinated mechanically. "Our earlier research has shown that blue-banded bees are effective pollinators of greenhouse tomatoes," Hogendoorn said. "This new finding suggests that blue-banded bees could also be very efficient pollinators—needing fewer bees per hectare." The research will be published in an upcoming print edition of scientific journal Arthropod-Plant Interactions. Explore further: Ensuring healthy bees for farms and trees More information: Callin M. Switzer et al. Shakers and head bangers: differences in sonication behavior between Australian Amegilla murrayensis (blue-banded bees) and North American Bombus impatiens (bumblebees), Arthropod-Plant Interactions (2015). DOI: 10.1007/s11829-015-9407-7


Ashwin Kumar E.N.,Mechanical and Manufacturing Engineering | Mat Isa N.,Mechanical and Manufacturing Engineering | Vignesh B.V.,Mechanical and Manufacturing Engineering | Kandasamy R.,Computational Fluid Dynamics
ARPN Journal of Engineering and Applied Sciences | Year: 2016

In this paper, we analyse the steady stagnation-point flow and heat transfer of an incompressible copper nanofluids towards a shrinking/stretching surface. Copper nanoparticles of volume fraction 0.2% are dispersed in fresh water and sea water. The governing Navier-Stokes' partial differential equations are transformed to a set of nonlinear ordinary differential equations by means of a similarity transformation. The nonlinear equations are then solved numerically by using Runge-Kutta-Fehlberg method with shooting technique. A comparison analyses on sea water/fresh water based copper nanofluids is presented to investigate the effect of injection under the influence of pertinent parameters such as the magnetic parameter, Grashof number, Eckert number, thermal radiation and heat generation are discussed over a vertical porous surface. The temperature and velocity distributions of nanofluids at the porous surface illustrates that both nanofluids have quite similar characteristics for all stream conditions. Comparisons with published results is presented. © 2006-2016 Asian Research Publishing Network (ARPN).


Panchal S.,Mechanical and Manufacturing Engineering | Dincer I.,Mechanical and Manufacturing Engineering | Agelin-Chaab M.,Mechanical and Manufacturing Engineering | Fraser R.,University of Waterloo | Fowler M.,University of Waterloo
Applied Thermal Engineering | Year: 2016

This paper deals with the thermal modeling and validation of temperature rise in a prismatic lithium-ion battery with LiFePO4 (also known as LFP) cathode material. The developed model represents the main thermal phenomena in the cell in terms of temperature distribution. A neural network approach is used for the model development. The proposed model is validated with the experimental data collected in terms of temperature and voltage profiles. In addition to this, the surface temperature distributions on the principal surface of the battery are studied under various discharge/charge profiles with varying boundary conditions (BCs) and average surface temperature distributions. For this, the different discharge rates of 2C and 4C and different boundary conditions (cooling/operating/bath temperature of 5 °C, 15°C, 25°C, and 35 °C) are selected. The results of this study show that the increased discharge rates result in increased surface temperature distributions on the principal surface of the battery. Furthermore, it is observed that changing the operating or boundary conditions considerably affect the surface temperature distributions. © 2015 Elsevier Ltd. All rights reserved.


Panchal S.,Mechanical and Manufacturing Engineering | Dincer I.,Mechanical and Manufacturing Engineering | Agelin-Chaab M.,Mechanical and Manufacturing Engineering | Fraser R.,University of Waterloo | Fowler M.,University of Waterloo
International Journal of Thermal Sciences | Year: 2016

This paper deals with the surface temperature distributions on the principal surface of the battery at 1C and 3C discharge rates and different boundary conditions (cooling/operating/bath temperature) of 5 °C, 15 °C, 25 °C, and 35 °C. The air cooling and water cooling system is designed and developed based on a prismatic Lithium-ion that has 20 Ah capacity. In addition, the battery thermal model is developed which represents the main thermal phenomena in the battery cell in terms of temperature distribution. The developed model is validated with the experimental data collected including temperature and discharge voltage profile. The results show that the average surface temperature distribution is higher at 3C discharge rate and 35 °C boundary conditions (BCs) and the average surface temperature distribution is lower 1C discharge rate and 5 °C BCs. Furthermore, it is observed that increased discharge rates and increased operating conditions or BCs result in increased surface temperature distributions of the battery. © 2015 Elsevier Masson SAS. All rights reserved.


Yildiz M.,Anadolu University | Karakoc H.,Anadolu University | Dincer I.,Mechanical and Manufacturing Engineering
International Communications in Heat and Mass Transfer | Year: 2016

This paper deals with the thermal modeling of temperature rise in a pouch lithium-ion battery with LiFePO4 (also known as LFP) cathode material. The developed model represents the main thermal phenomena in the cell in terms of temperature change. The proposed model is validated with the collected experimental data from a module composed of 11 cells. In the conducted experiments, the different charge and discharge rates of 1/2C, 1C, 2C and 2.5C are applied. It is seen that, the increased discharge rates result in increased temperature on the surface of the battery. When the discharge rate is doubled, from 1C to 2C, cell temperatures have risen by 3.5 times. A simplified model for determining the heat generation is developed and validated with the test results. © 2016.

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