A novel kinetic energy harvesting system for lifetime deployments of wildlife trackers.

Wildlife tracking devices are key in obtaining detailed insights on movement, animal migration, natal dispersal, home-ranges, resource use and group dynamics of free-roaming animals. Despite a wide use of such devices, tracking for entire lifetimes is still a considerable challenge for most animals, mainly due to technological limitations. Deploying battery powered wildlife tags on smaller animals is limited by the mass of the devices. Micro-sized devices with solar panels sometimes solve this challenge, however, nocturnal species or animals living under low light conditions render solar cells all but useless. For larger animals, where battery weight can be higher, battery longevity becomes the main challenge. Several studies have proposed solutions to these limitations, including harvesting thermal and kinetic energy on animals. However, these concepts are limited by size and weight. In this study, we used a small, lightweight kinetic energy harvesting unit as the power source for a custom wildlife tracking device to investigate its suitability for lifetime animal tracking. We integrated a Kinetron MSG32 microgenerator and a state-of-the-art lithium-ion capacitor (LIC) into a custom GPS-enabled tracking device that is capable of remotely transmitting data via the Sigfox 'Internet of Things' network. Prototypes were tested on domestic dog (n = 4), wild-roaming Exmoor pony (n = 1) and wisent (n = 1). One of the domestic dogs generated up to 10.04 joules of energy in a day, while the Exmoor pony and wisent generated on average 0.69 joules and 2.38 joules per day, respectively. Our results show a significant difference in energy generation between animal species and mounting method, but also highlight the potential for this technology to be a meaningful advancement in ecological research requiring lifetime tracking of animals. The design of the Kinefox is provided open source.

In Vitro Simulation of Tissue Back-Pressure for Pen Injectors and Auto-Injectors.

The aim of this project was to show that tissue back-pressure can be measured in vitro using a simple pneumatic model. A thorough literature study revealed 4 relevant papers all describing in vivo studies. One of these studies where the subcutaneous tissue back-pressure was determined in 11 patients was used as a reference for the present work. A pneumatic model capable of simulating the back-pressure and the diffusion of drug during subcutaneous injection was developed. The in vitro model was tested using the same type of pen injector as used in the reference study. Comparison of the results revealed that the measured pressure in the in vitro experiments was similar to the subcutaneous tissue back-pressure measured in vivo. G30 0.3 × 8.0 mm and G32 0.23/0.25 × 4.0 mm needles were used for the in vitro experiments, whereas a G31 0.25 × 6.0 mm needle was used for the in vivo experiments. This is one possible explanation of approximately 30 µL/s higher flow rates for the in vitro experiments compared to the in vivo experiments. The low-complexity model allows repeated measurements and provides a stable data output paving the way for measuring subcutaneous back-pressure in vitro.