scholarly journals Minimum cost of transport in Asian elephants: do we really need a bigger elephant?

2012 ◽  
Vol 215 (9) ◽  
pp. 1509-1514 ◽  
Author(s):  
V. A. Langman ◽  
M. F. Rowe ◽  
T. J. Roberts ◽  
N. V. Langman ◽  
C. R. Taylor
Keyword(s):  
Minimum Cost ◽  
Cost Of Transport ◽  
Asian Elephants

Hydrodynamic drag in steller sea lions (Eumetopias jubatus)

2000 ◽  
Vol 203 (12) ◽  
pp. 1915-1923 ◽  
Author(s):  
L.L. Stelle ◽  
R.W. Blake ◽  
A.W. Trites
Keyword(s):  
Minimum Cost ◽  
The Body ◽  
Hydrodynamic Drag ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
California Sea Lions ◽  
Cost Of Transport ◽  
Sea Lions ◽  
Drag Forces ◽  
The Individual

Drag forces acting on Steller sea lions (Eumetopias jubatus) were investigated from ‘deceleration during glide’ measurements. A total of 66 glides from six juvenile sea lions yielded a mean drag coefficient (referenced to total wetted surface area) of 0.0056 at a mean Reynolds number of 5.5×10(6). The drag values indicate that the boundary layer is largely turbulent for Steller sea lions swimming at these Reynolds numbers, which are past the point of expected transition from laminar to turbulent flow. The position of maximum thickness (at 34 % of the body length measured from the tip of the nose) was more anterior than for a ‘laminar’ profile, supporting the idea that there is little laminar flow. The Steller sea lions in our study were characterized by a mean fineness ratio of 5.55. Their streamlined shape helps to delay flow separation, reducing total drag. In addition, turbulent boundary layers are more stable than laminar ones. Thus, separation should occur further back on the animal. Steller sea lions are the largest of the otariids and swam faster than the smaller California sea lions (Zalophus californianus). The mean glide velocity of the individual Steller sea lions ranged from 2.9 to 3.4 m s(−)(1) or 1.2-1.5 body lengths s(−)(1). These length-specific speeds are close to the optimum swim velocity of 1.4 body lengths s(−)(1) based on the minimum cost of transport for California sea lions.

Efficiency of uphill locomotion in nocturnal and diurnal lizards

1996 ◽  
Vol 199 (3) ◽  
pp. 587-592 ◽  
Author(s):  
C Farley ◽  
M Emshwiller
Keyword(s):  
Body Mass ◽  
Low Cost ◽  
Minimum Cost ◽  
Mechanical Work ◽  
Energetic Cost ◽  
Cost Of Transport ◽  
Unit Distance ◽  
Cost Of Locomotion ◽  
Average Body Mass ◽  
Average Body

Nocturnal geckos can walk on level ground more economically than diurnal lizards. One hypothesis for why nocturnal geckos have a low cost of locomotion is that they can perform mechanical work during locomotion more efficiently than other lizards. To test this hypothesis, we compared the efficiency of the nocturnal gecko Coleonyx variegatus (average body mass 4.2 g) and the diurnal skink Eumeces skiltonianus (average body mass 4.8 g) when they performed vertical work during uphill locomotion. We measured the rate of oxygen consumption when each species walked on the level and up a 50 slope over a range of speeds. For Coleonyx variegatus, the energetic cost of traveling a unit distance (the minimum cost of transport, Cmin) increased from 1.5 to 2.7 ml O2 kg-1 m-1 between level and uphill locomotion. For Eumeces skiltonianus, Cmin increased from 2.5 to 4.7 ml O2 kg-1 m-1 between level and uphill locomotion. By taking the difference between Cmin for level and uphill locomotion, we found that the efficiency of performing vertical work during locomotion was 37 % for Coleonyx variegatus and 19 % for Eumeces skiltonianus. The similarity between the 1.9-fold difference in vertical efficiency and the 1.7-fold difference in the cost of transport on level ground is consistent with the hypothesis that nocturnal geckos have a lower cost of locomotion than other lizards because they can perform mechanical work during locomotion more efficiently.

Locomotion in the abalone Haliotis kamtschatkana: pedal morphology and cost of transport

1997 ◽  
Vol 200 (7) ◽  
pp. 1145-1153 ◽  
Author(s):  
D Donovan ◽  
T Carefoot
Keyword(s):  
Shell Length ◽  
Minimum Cost ◽  
Regression Equations ◽  
Cost Of Transport ◽  
Linear Relationships ◽  
Rate Of Oxygen Consumption ◽  
Body Sizes ◽  
Locomotion Cost ◽  
Mass In G ◽  
Escape Speed

Morphological analyses of pedal sole area and pedal waves were conducted for a range of speeds and body sizes in the abalone Haliotis kamtschatkana. The pedal sole of resting abalone increased in size disproportionately with animal volume (slope of log10-transformed data, b=0.83; expected slope for isometry, b0=0.67) and length (b=2.51; b0=2.0). Pedal wave frequency increased linearly with speed, confirming that abalone increase speed by increasing the velocity of pedal waves. Total area of the pedal sole decreased by 2.1 % for each shell length per minute increase in speed. Likewise, the area of the foot incorporated into pedal waves increased by 1.8 % for each shell length per minute increase in speed. Together, these changes translated into a 50 % decrease in the pedal sole area in contact with the substratum at a maximum escape speed of 15 shell lengths min-1, relative to the pedal sole at rest. The amount of mucus secreted by resting animals during adhesion to the substratum increased isometrically with foot area (slope of log10-transformed data, b=1.08). The amount of mucus secreted during locomotion did not vary with speed, but was less than the amount needed for adhesion. We suggest that these morphological and physiological changes reduce the energy expenditure during locomotion. Cost of transport was investigated for a range of speeds and abalone sizes. The rate of oxygen consumption O2 (in µl O2 g-1 h-1) increased linearly with increasing absolute speed v (in cm min-1): O2=40.1+0.58v-0.15m (r2=0.35, P=0.04), where m is body mass (in g). Minimum cost of transport, calculated from the slope of absolute speed on O2, was 20.3 J kg-1 m-1. Total cost of transport (COTT) and net cost of transport (COTN) were high at low speeds and decreased as speed increased, to minima of 86.0 J kg-1 m-1 and 29.7 J kg-1 m-1, respectively, at speeds measured in the respirometer. Log10-transformation of both cost of transport and speed data yielded linear relationships with the following regression equations: log10COTT=3.35-0.90log10v-0.21log10m (r2=0.89; P<0.006) and log10COTN=2.29-0.69log10v-0.09log10m (r2=0.48; P<0.006), respectively.

Optimal fineness ratio for minimum drag in large whales

2009 ◽  
Vol 87 (2) ◽  
pp. 124-131 ◽  
Author(s):  
Boye K. Ahlborn ◽  
Robert W. Blake ◽  
Keith H.S. Chan
Keyword(s):  
Minimum Cost ◽  
Cylindrical Body ◽  
Positive Dependence ◽  
Cost Of Transport ◽  
Pressure Drag ◽  
Minimum Drag ◽  
Profile Height ◽  
Energy Cost Of Swimming ◽  
Ratio Versus ◽  
Hydromechanical Model

The optimum fineness ratio (X = L/d, where L and d are body length and profile height, respectively) for minimum drag is about 4.5 and many fast swimming fish are characterized by values of this order. However, values for large whales that undergo extensive migrations (e.g., Balaenopteridae, Balaenidae, and Physeteridae) are as high as 8. A plot of fineness ratio versus mass (M) for different species of large whales shows that the optimal fineness ratio for minimum drag and therefore the minimum cost of transport increases slowly with increasing mass (X = 4M0.06). Optimal fineness ratio was determined from a simple hydromechanical model based on the sum of friction and pressure drag on an equivalent cylindrical body, which indicate a small positive dependence (0.11) of optimal fineness ratio for minimum drag with increasing body mass, suggesting an adaptation for reducing the energy cost of swimming.

scholarly journals EXTENSION OF THE MINIMUM COST FLOW PROBLEM (MCFP OR CNF) BY CONSIDERATION OF TIME AND QUANTITY OF LOADS WITH MAXIMUM TIME

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Omer Kurtanović ◽  
Haris Dacić ◽  
Admir Kurtanović
Keyword(s):  
Minimum Cost ◽  
Linear Constraints ◽  
Transport Time ◽  
Cost Of Transport ◽  
Closed Model ◽  
The Road ◽  
Maximum Time ◽  
Software Algorithms ◽  
Time Problem ◽  
On The Road

This paper extends the general problem of minimizing the total cost of transport on the road network (CNF) by considering the total time, maximum time and total amount of cargo with the longest time. In the literature available to us, models with timing and amount of cargo in the case of a standard transport task were exposed. Optimization is possible by combining 5 criteria, 2 linear and 3 nonlinear ones over the same set of linear constraints. Multicriteria optimization determines Pareto-optimal solutions. Interactive analyst-software algorithms for solving the selected models were defined. The solution of hypothetical problems was illustrated. Closed model with 5 two-way asymmetric communications using software for CNF and it is possible to use software for LP. Four one-criteria problems were solved: total costs, overall transport performance from a time standpoint, transport time (problem of the second type by time) total transport time (problem of the third type by time) and one bi-criteria problem related to the simultaneous minimization of the maximum duration of transport and total costs.

scholarly journals Bioenergetic and kinematic consequences of limblessness in larval Diptera

1993 ◽  
Vol 179 (1) ◽  
pp. 245-259 ◽  
Author(s):  
D. Berrigan ◽  
J. R. Lighton
Keyword(s):  
Minimum Cost ◽  
Cost Of Transport ◽  
Terrestrial Locomotion ◽  
Contraction Frequency ◽  
Fly Larvae ◽  
The Cost ◽  
Peristaltic Contractions ◽  
The Relationship ◽  
Very High ◽  
Kinematic Properties

We report the cost of transport and kinematics of terrestrial locomotion by larval blowflies (Protophormia terraenovae, Diptera: Calliphoridae). We contrast inter- and intra-individual methods for estimating minimum cost of transport (MCOT) and the relationship between speed, contraction frequency and distance traveled per contraction. The minimum cost of transport calculated from intra-individual data is 2297 +/− 317 J kg-1 m-1 (S.E.M.) and the MCOT calculated from inter-individual comparisons is statistically indistinguishable at 1910 +/− 327 J kg-1 m-1. These values are almost ten times higher than the predicted value for a similar-sized limbed arthropod. Fly larvae travel by repeated peristaltic contractions and individual contractions cost about the same amount as individual strides in limbed insects. Both contraction frequency and distance traveled per contraction increase linearly with speed. Doubling the contraction frequency or the distance traveled per contraction approximately doubles speed. The cost of transport in fly larvae is among the highest recorded for terrestrial locomotion, confirming the suggestion that biomechanical and kinematic properties of limbless organisms with hydraulic skeletons lead to very high costs of transport.

scholarly journals Energetics of Hermit Crabs during Locomotion: The Cost of Carrying a Shell

1986 ◽  
Vol 120 (1) ◽  
pp. 297-308 ◽  
Author(s):  
CLYDE F. HERREID ◽  
ROBERT J. FULL
Keyword(s):  
Fuel Economy ◽  
Low Cost ◽  
Minimum Cost ◽  
Hermit Crabs ◽  
Absolute Difference ◽  
Cost Of Transport ◽  
The Difference ◽  
The Cost ◽  
Response To Exercise ◽  
Leg Position

Oxygen consumption (VOO2) was measured as hermit crabs (Coenobita compressus) walked at controlled velocities on a motor-driven treadmill inside a small respirometer. The crabs displayed an aerobic response to exercise with a rapid increase in VOO2 reaching a steady state in about 5–6 min followed by a rapid recovery. The highest VOO2 was four times the resting rate. VOO2 was directly dependent on the velocity of travel (V): VOO2 = 0.29+1.98V. Metabolic rate was increased significantly in crabs with bilateral leg ablation. The cost of shell carrying was evaluated by comparing VOO2 of crabs with and without their protective snail shells at different velocities; the absolute difference was constant (0.17 ml O2g−1 h−1), suggesting that the cost of shell support was constant per unit of time regardless of speed. The cost of transport dropped dramatically with speed for crabs both with and without snail shells. Crabs carrying shells used twice as much O2 per gram per kilometre as did ‘nude’ crabs walking slowly at 0.02 kmh−1 but the difference decreased to 1.3 times when velocity was increased 10-fold. Hermit crabs did not increase their VOO2 proportionately with load: the VOO2 loaded/unloaded ratio was consistently less than the mass loaded/unloaded ratio. This apparent increase in efficiency may be due to the fact that crabs carrying heavy shells alter their leg position and tend to drag their shell. Crabs with and without shells have the same minimum cost of transport CM, so travel at the highest velocity is theoretically the most economical way to cover a given distance. Appropriately, crabs on the beach average a fast 0.23 km h−1 which produces a low cost of transport only 1.3 times higher than CM. The CM of six-legged hermit crabs is comparable to that of mammals, birds, crabs and insects of similar size and indicates that leg number does not affect fuel economy.

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