Dynamic body acceleration as a proxy to predict the cost of locomotion in bottlenose dolphins

Estimates of the energetic costs of locomotion (COL) at different activity levels are necessary to answer fundamental eco-physiological questions and to understand the impacts of anthropogenic disturbance to marine mammals. We combined estimates of energetic costs derived from breath-by-breath respirometry with measurements of overall dynamic body acceleration (ODBA) from biologging tags to validate ODBA as a proxy for COL in trained common bottlenose dolphins (Tursiops truncatus). We measured resting metabolic rate (RMR); mean individual RMR was 0.71-1.42 times that of a similarly sized terrestrial mammal and agreed with past measurements which used breath-by-breath and flow-through respirometry. We also measured energy expenditure during submerged swim trials, at primarily moderate exercise levels. We subtracted RMR to obtain COL, and normalized COL by body size to incorporate individual swimming efficiencies. We found both mass-specific energy expenditure and mass-specific COL were linearly related with ODBA. Measurements of activity level and cost of transport (the energy required to move a given distance) improve understanding of the costs of locomotion in marine mammals. The strength of the correlation between ODBA and COL varied among individuals, but the overall relationship can be used at a broad scale to estimate the energetic costs of disturbance, daily locomotion costs to build energy budgets, and investigate the costs of diving in free-ranging animals where bio-logging data are available. We propose that a similar approach could be applied to other cetacean species.

Behaviour, temperature and terrain slope impact estimates of energy expenditure using oxygen and dynamic body acceleration

The energy used by animals is influenced by intrinsic (e.g. physiological) and extrinsic (e.g. environmental) factors. Accelerometers within biologging devices have proven useful for assessing energy expenditures and their behavioural context in free-ranging animals. However, certain assumptions are frequently made when acceleration is used as a proxy for energy expenditure, with factors, such as environmental variation (e.g. ambient temperature or slope of terrain), seldom accounted for. To determine the possible interactions between behaviour, energy expenditure and the environment (ambient temperature and terrain slope), the rate of oxygen consumption ($${\dot{\text{V}}\text{O}}_{2}$$ V ˙ O 2 ) was measured in pygmy goats (Capra hircus aegarus) using open-flow indirect calorimetry. The effect of temperature (9.7–31.5 °C) on resting energy expenditure was measured. The relationship between $${\dot{\text{V}}\text{O}}_{2}$$ V ˙ O 2 and dynamic body acceleration (DBA) was measured at different walking speeds (0.8–3.0 km h−1) and on different inclines (0, + 15°, − 15°). The daily behaviour of individuals was measured in two enclosures: enclosure A (level terrain during summer) and enclosure B (sloped terrain during winter) and per diem energy expenditures of behaviours estimated using behaviour, DBA, temperature, terrain slope and $${\dot{\text{V}}\text{O}}_{2}$$ V ˙ O 2 . During rest, energy expenditure increased below 22 °C and above 30.5 °C. $${\dot{\text{V}}\text{O}}_{2}$$ V ˙ O 2 (ml min−1) increased with DBA when walking on the level. Walking uphill (+ 15°) increased energetic costs three-fold, whereas walking downhill (− 15°) increased energetic costs by one third. Based on these results, although activity levels were higher in animals in enclosure A during summer, energy expenditure was found to be significantly higher in the sloped enclosure B in winter (means of enclosures A and B: 485.3 ± 103.6 kJ day−1 and 744.5 ± 132.4 kJ day−1). We show that it is essential to account for extrinsic factors when calculating animal energy budgets. Our estimates of the impacts of extrinsic factors should be applicable to other free ranging ungulates.

A Hydromechanical Perspective to Study the Effect of Body Acceleration through Stenosed Artery

The spread of numerous deadly diseases such as Thrombosis, Diabetes, Atherosclerosis and other cardiac diseases, carry on to be major root of demise and growing public curiosity about the prevention and treatment of such fatal disorders. Body acceleration has very important role on the flow through stenosed artery. In this research work a problem for irregular development in the inner wall of the artery is known atherosclerosis that settled as a result of buildup due to cholesterol on the arterial wall has been discussed. In this work the effects of body acceleration, slip velocity in presence of catheter on the wall shear, velocity profile and flow rate reveal the graphical finding for pulsatile blood flow in narrow blood vessels. Here it is shown that flow rate, velocity and shear stress escalate as body acceleration increases.

Analytical Investigation of Magnetohydrodynamic Non-Newtonian Type Casson Nanofluid Flow past a Porous Channel with Periodic Body Acceleration

The consequence of periodic body acceleration and thermal radiation in the pulsating flow of MHD Casson nanofluid through a porous channel is addressed. A flow of the nanofluid injected through the lower plate is considered while sucked out through the upper plate with a similar velocity. The thermal radiation term is incorporated in the heat transfer equation. The governing equations corresponding to velocity and temperature are converted from partial differential equations to a system of ordinary differential equations by employing similarity variables. The perturbation technique is applied to solve the governing flow equations. The impact of diverse parameters on flow features is graphically analyzed. The result reveals that adding the nanoparticle has enhanced the velocity profile of the base fluid. Moreover, an increase in the periodic body acceleration results in enlarging velocity and temperature.

Intelligent Cuckoo Search Algorithm of PID and Skyhook Controller for Semi-Active Suspension System using Magneto-Rheological Damper

This article introduces the application of the Cuckoo Search (CS) Algorithm to tune Proportional-Integral-Derivative (PID) and Skyhook controller for the semi-active (SA) suspension system further to improve the vehicle’s ride comfort and stability. Meanwhile, the PID-CSA and Skyhook-CSA intelligent approaches have been compared to the passive suspension system. The performances of the PID controller and Skyhook controller are optimised by Cuckoo Search (CS) Algorithm, respectively. The system’s mean square error (MSE) is defined as an objective function for optimising the proposed controllers. The performance of the proposed PID-CSA and Skyhook-CSA controllers are evaluated with the passive suspension system in the form of body acceleration, body displacement, and tire acceleration. The sinusoidal road profile is set as the disturbance of this system. The percentage improvement for body acceleration and body displacement achieved about 25% for the PID-CSA controller and 1-4% for Skyhook-CSA. These simulated results reflect that the proposed controllers outperformed in comparison with other considered methods to obtain the most effective vehicle stability and ride comfort.

Development and Control of Power-Assisted Lumbar Suit Based on Upper-Body Acceleration

In this study, we propose a method to estimate the assistive timing requirements for a power-assisted lumbar suit based on upper-body acceleration. Our developed power-assisted suit combines of springs, wires, and an electrical motor to provide efficient assistance. The assistive torque provided by the suit was determined based on a digital human model. The assistive timing using the electrical motor was calculated from the upper-body acceleration measured using two internal accelerometers. Herein, we present the experimental results based on the myoelectricity of a muscle during lifting motions involving three participants acting as caregivers to elderly patients.

Study on adverse effect suppression of hub motor driven vehicles with inertial suspensions

With increasingly severe energy supply and environmental pollution, Hub Motor Driven Vehicle (HMDV) have become the ideal configuration for future electric vehicles. The adverse effect caused by the significant increase in HMDV unsprung mass directly affects the vehicle ride comfort and handling stability, becomes a technical bottleneck for theoretical research and industrial development to be solved urgently. The HMDV adverse effect should be suppressed by the vehicle suspension system, which can be classified as vertical motion inertia instability caused by the increase of unsprung mass, but the lack of inertial elements in the conventional suspension “damping-spring” structure restricts the overall performance of the suspension. Therefore, the inertial suspension containing the inertial element “inerter” is utilized to effectively distribute the HMDV vertical motion inertia to suppress its adverse effects. First, the adverse effects of increased unsprung mass on vehicle ride comfort and road friendliness are studied. Then, the inertial suspension models of different structures are established and their impedance expressions are derived. Thirdly, the impact of the inertance in the inertial suspension on the suppression of the HMDV adverse effect is studied. Finally, the particle swarm optimization algorithm is utilized to optimize the parameters of the inertial suspension to improve the performance of the suspension. The results show that the inertial suspension can reduce the RMS value of body acceleration and dynamic tire load. The RMS value of body acceleration and dynamic tire load of the L4 structure is reduced by 8.1% and 16.38% respectively. It shows that the inertial suspension can effectively suppress the HMDV vertical adverse effect, improve the HMDV ride comfort and road friendliness, and lay the foundation for the subsequent suppression research.