scholarly journals Environmental correlates and functional consequences of bill divergence in island song sparrows

2021 ◽  
Author(s):  
Maybellene P Gamboa ◽  
Cameron K Ghalambor ◽  
T Scott Sillett ◽  
W Chris Funk ◽  
Ross A Furbush ◽  
...  
Keyword(s):  
Surface Area ◽  
Heat Dissipation ◽  
Song Sparrow ◽  
Maximum Temperature ◽  
Foraging Efficiency ◽  
Channel Islands ◽  
Environmental Selection ◽  
Song Sparrows ◽  
Functional Consequences ◽  
Bill Morphology

Inferring the environmental selection pressures responsible for phenotypic variation is a challenge in adaptation studies as traits often have multiple functions and are shaped by complex selection regimes. We provide experimental evidence that morphology of the multifunctional avian bill is related to climate, not foraging efficiency, in song sparrows (Melospiza melodia) on the California Channel Islands. Our research builds on a study in song sparrow museum specimens that demonstrated a positive correlation between bill surface area and maximum temperature, suggesting a greater demand for dry heat dissipation in hotter, xeric environments. We sampled contemporary sparrow populations across three climatically distinct islands to test the alternate hypotheses that song sparrow bill morphology is either a product of vegetative differences with functional consequences for foraging efficiency or related to maximum temperature and, consequently, important for thermoregulation. Measurements of >500 live individuals indicated a significant, positive relationship between maximum temperature and bill surface area when correcting for body size. In contrast, maximum bite force, seed extraction time, and vegetation on breeding territories (a proxy for food resources) were not significantly associated with bill dimensions. While we cannot exclude the influence of foraging ability and diet on bill morphology, our results are consistent with the hypothesis that variation in song sparrows' need for thermoregulatory capacity across the northern Channel Islands selects for divergence in bill surface area.

Development and stability of single-parent family units in the song sparrow

1980 ◽  
Vol 58 (10) ◽  
pp. 1869-1875 ◽  
Author(s):  
James N. M. Smith ◽  
Juan R. Merkt
Keyword(s):  
Single Parent ◽  
Song Sparrow ◽  
Single Parent Family ◽  
Song Sparrows ◽  
The One

Allocation of parental feedings to newly fledged young was observed in 34 song sparrow broods on the day of leaving the nest (day 0) and in five more broods the subsequent day (day 1). In the one case in which leaving the nest was observed, feedings were immediately divided between parents so that each young was fed by only one parent. Four-fifths of all young were fed by only a single parent on day 0 or day 1: the remaining fifth were fed by both parents during observation periods of about 90 min. Twenty-nine of the same broods were observed again during days 4–8, when only 1 of 82 young was fed by both parents. Slightly more young were fed by males than on days 0–1. The tendency for males to care for a higher proportion of older young occurred whether or not the pair began a further brood. Song sparrow fledglings gave individually distinct food begging calls. These may have assisted the formation or maintenance of specific parent–young feeding units. Brown-headed cowbird young in the brood were treated like song sparrows, except that they were fed more frequently.

scholarly journals Context-dependent effects of relative temperature extremes on bill morphology in a songbird

2020 ◽  
Vol 7 (4) ◽  
pp. 192203
Author(s):  
Katie LaBarbera ◽  
Kyle J. Marsh ◽  
Kia R. R. Hayes ◽  
Talisin T. Hammond
Keyword(s):  
Extreme Environments ◽  
Negative Relationship ◽  
Environmental Context ◽  
Maximum Temperature ◽  
Relative Temperature ◽  
Generalist Species ◽  
Environmental Extremes ◽  
Bill Morphology ◽  
Thermoregulatory Function ◽  
Cool Climate

Species increasingly face environmental extremes. Morphological responses to changes in average environmental conditions are well documented, but responses to environmental extremes remain poorly understood. We used museum specimens to investigate relationships between a thermoregulatory morphological trait, bird bill surface area (SA) and a measure of short-term relative temperature extremity (RTE), which quantifies the degree that temperature maxima or minima diverge from the 5-year norm. Using a widespread, generalist species, Junco hyemalis , we found that SA exhibited different patterns of association with RTE depending on the overall temperature regime and on precipitation. While thermoregulatory function predicts larger SA at higher RTE, we found this only when the RTE existed in an environmental context that opposed it: atypically cold minimum temperature in a warm climate, or atypically warm maximum temperature in a cool climate. When environmental context amplified the RTE, we found a negative relationship between SA and RTE. We also found that the strength of associations between SA and RTE increased with precipitation. Our results suggest that trait responses to environmental variation may qualitatively differ depending on the overall environmental context, and that environmental change that extremifies already-extreme environments may produce responses that cannot be predicted from observations in less-extreme contexts.

Effect of Stator Surface Area on Braking Torque and Wall Heat Dissipation of Magnetorheological Fluid Retarder

2020 ◽  
Author(s):  
ZhiQiang Liu ◽  
Gangfeng Tan ◽  
Zhongpeng Tian ◽  
Mi Zhou ◽  
Philip Agyeman ◽  
...  
Keyword(s):  
Surface Area ◽  
Heat Dissipation ◽  
Magnetorheological Fluid ◽  
Braking Torque

Temperature Spectrums of an Automotive Environment for Fatigue Reliability Analysis

1994 ◽  
Vol 37 (6) ◽  
pp. 19-25
Author(s):  
Jimmy Hu ◽  
Ken Salisbury
Keyword(s):  
Heat Dissipation ◽  
Sun Exposure ◽  
Maximum Temperature ◽  
Fatigue Reliability ◽  
Temperature Spectrum ◽  
Electronic Products ◽  
Automotive Components ◽  
Thermal Fatigue Life ◽  
Temperature Ranges ◽  
Nominal Temperature

The temperature spectrum of an automotive environment is a necessary input to predict thermal fatigue life, to estimate product reliability, and to specify accelerated thermal cycle testing for automotive components. This paper investigates the temperature profiles of electronic products located in the engine compartment (EC), the engine-mounted (EM) area, and the passenger/luggage (P/L) compartment, and develops the nominal temperature spectrums for these vehicle locations. The daily climatic temperatures of various geographical areas in the U.S. are analyzed. The effects of sun exposure and operational heat dissipation on the maximum temperature in three vehicle compartments are investigated. Due to the proportionality of mechanical stress/strain ranges and temperature ranges, the temperature spectrums are constructed by using the rainflow method for fatigue cycle counting.

Next Generation Insert for Forced Coolant Application in Machining of Inconel 718

2016 ◽  
Vol 836-837 ◽  
pp. 340-347 ◽  
Author(s):  
Nageswaran Tamil Alagan ◽  
Tomas Beno ◽  
Anders Wretland
Keyword(s):  
Tool Wear ◽  
Surface Area ◽  
Inconel 718 ◽  
Material Removal ◽  
Metal Cutting ◽  
Heat Dissipation ◽  
Catastrophic Failure ◽  
Mass Ratio ◽  
Next Generation ◽  
Primary Focus

Machining technology has undergone an extensive evolution throughout the last decades in its capability to machine hard-to-cut material. This paper will discuss about the next generation insert with cooling feature coupled with forced coolant in machining Inconel 718. The geometry of the insert was changed in a way which has enlarged the surface area approximately 12% compared to regular insert named as nusselt insert. The idea applied in “nusselt insert” was the relation of increase in surface area to heat dissipation. Forced coolant application has become a way to improve existing metal cutting concepts and improve their current material removal rates without any need for a reengineered machining process.Experiments conducted on the inserts is that the first experiment of its kind in machining technology together with forced coolant and tested in four different inserts. The primary focus of the work was the investigation of the relation between the heat dissipation with an increase in surface area/mass ratio in the cutting interface based on its influence on tool wear. The experimental results showed the nusselt insert have better ability for heat dissipation which has led to significant reduce in tool wear and successfully facing Inconel 718 at vc 105 m/min, f 0.3 mm/rev and ap 1 mm where the regular insert had a catastrophic failure at vc 90 m/min, f 0.1 mm/rev and ap 1 mm. Nusselt insert has shown to increase MRR significantly compared to regular insert.

scholarly journals The effects of habituation on boldness of urban and rural song sparrows (Melospiza melodia)

Behaviour ◽  
2021 ◽  
pp. 1-15
Author(s):  
Taylor Elaine Fossett ◽  
Jeremy Hyman
Keyword(s):  
Repeated Exposure ◽  
Melospiza Melodia ◽  
Song Sparrow ◽  
Rural Populations ◽  
Flight Initiation Distance ◽  
Urban Birds ◽  
Wildlife Species ◽  
Song Sparrows ◽  
Rural And Urban ◽  
Flight Initiation

Abstract As urbanization increases globally, wildlife species are changing their behaviour in many ways. Urban animals are often bolder, or less fearful of new stimuli, than rural animals. While adaptation can drive behavioural changes in urban animals, other factors, such as learning or habituation, can also lead to behavioural modifications. To determine how repeated exposure to a non-threatening human affects song sparrow (Melospiza melodia) behaviour in urban and rural habitat, we measured boldness as flight initiation distance (FID), for 5 consecutive days. We found that urban birds had consistently lower FID’s than their rural counterparts from days 1–4, yet there was no difference in rural and urban FID by trial 5. FID decreased over 5 days of repeated trials in the rural populations, but not the urban. These results suggest that habituation can occur quickly in rural birds and may account for the greater boldness we typically see in urban populations.

scholarly journals Simulation of heat dissipation model of lithium-ion battery pack

2021 ◽  
Vol 300 ◽  
pp. 01014
Author(s):  
Maode Li ◽  
Chuan He ◽  
Jinkui Zheng
Keyword(s):  
Phase Change ◽  
Temperature Rise ◽  
Heat Dissipation ◽  
Lithium Ion ◽  
Maximum Temperature ◽  
Air Cooling ◽  
Power Battery ◽  
Staggered Arrangement ◽  
Dissipation Model ◽  
Cooling Methods

Lithium-ion power battery has become an important part of power battery. According to the performance and characteristics of lithiumion power battery, the influence of current common charge and discharge and different cooling methods on battery performance was analysed in this paper. According to the software simulation, in the 5C charge-discharge cycle, the maximum temperature of the cells with regular arrangement is 57.97°C, the maximum temperature of the cells with staggered arrangement is 55.83°C, and the maximum temperature of phase change cooling is 47.42°C. The most important thing is that the temperature difference between the cells with phase change cooling is only 5.5°C. Some simulation results of air cooling and phase change show that phase change cooling can control the heat dissipation and temperature rise of power battery well. The research in this paper can provide better theoretical guidance for the temperature rise, heat transfer and thermal management of automotive power battery.

Improved Heat Dissipation Capability on Electronic Motor Control Devices

2005 ◽  
Author(s):  
Wei Tong
Keyword(s):  
Heat Transfer ◽  
Motor Control ◽  
Heat Dissipation ◽  
Electronic Devices ◽  
Heat Sinks ◽  
Vortex Generators ◽  
Maximum Temperature ◽  
Complex Heat Transfer ◽  
Pin Fins ◽  
Control Devices

Heat sinks have been widely used in electronic industry to maintain the operation temperatures of electronic devices lower than their allowable values and thus are often critical to the device performance and life. However, it is difficult to design heat sinks to satisfy all design specifications optimally under complex heat transfer phenomena. The present work discloses a new design of heat sinks to improve heat dissipation capability for electric motor control devices. The heat sink contains a plurality of raindrop-shaped pin fins, acting as vortex generators to increase the rate of heat transfer and in turn, to increase the cooling efficiency of the heat sinks. Numerical results have shown that with the new designed heat sinks, the maximum temperature can reduce about 30% over the conventional heat sinks.

A Novel Concept to Improve the Performance of LED Panel Using Drilled Holes

2005 ◽  
Author(s):  
S. B. Chiang ◽  
C. C. Wang
Keyword(s):  
Heat Transfer ◽  
Surface Area ◽  
Heat Sink ◽  
Maximum Temperature ◽  
Transfer Coefficients ◽  
Pin Fin ◽  
Heat Transfer Coefficients ◽  
Pin Fins ◽  
Overall Performance ◽  
Novel Concept

In this study, the concept of the thermal module of LEDs cooling by use of drilled hole to entrain air flow was examined. It is found that the drilled hole does not necessarily improve the overall performance. It depends on the size of the drilled hole, the number of drilled holes, and the locations. The heat transfer coefficients are generally increased with the number of drilled holes and the diameter of the drilled hole. In this paper, the plate fin heat sink has a higher heat transfer coefficients than pin fins, but the overall performance of the LED panel having pin fin outperforms that of plate fin. This is because the pin fin provides much larger surface area. For decrease the maximum temperature of the LED panel, placement of the drilled holes along the hot region will be more effective.

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