Is tagging with visual implant elastomer a reliable technique for marking earthworms?

Visual implant elastomer (VIE) has recently been employed to investigate different aspects of earthworm ecology. However, a number of fundamental questions relating to the detection and positioning of the tag, its persistence and potential effects on earthworms remain unknown. Seven earthworm species belonging to three ecological groupings, with different pigmentation and burrowing behaviour, were tagged using different coloured VIE. External inspection after two days, one week and 1, 10 and 27 months were followed by preservation, dissection and internal inspection. Tags could be seen in living specimens to 27 months, and dissection revealed that in most cases they were lodged in the coelomic cavity, held in place by septa. However, over longer time periods (more than two years), the chlorogogenous tissue tended to bind to the tags and made external observation increasingly difficult. Migration of the VIE material towards the posterior of the earthworm and potential loss of the tag were only observed on rare occasions, and a recovery rate in excess of 98% was recorded. By introducing a reasonable amount of VIE into segments, just after the clitellum, this technique can become a valuable tool in earthworm ecology and life history studies, particularly in short-medium term laboratory and field experiments

Determination of fungal activity in modified wood by means of micro-calorimetry and determination of total esterase activity

Beech and pine wood blocks were treated with 1,3-dimethylol-4,5-dihydroxyethylen urea (DMDHEU) to increasing weight percent gains (WPG). The resistance of the treated specimens against Trametes versicolor and Coniophora puteana, determined as mass loss, increased with increasing WPG of DMDHEU. Metabolic activity of the fungi in the wood blocks was assessed as total esterase activity (TEA) based on the hydrolysis of fluorescein diacetate and as heat or energy production determined by isothermal micro-calorimetry. Both methods revealed that the fungal activity was related with the WPG and the mass loss caused by the fungi. Still, fungal activity was detected even in wood blocks of the highest WPG and showed that the treatment was not toxic to the fungi. Energy production showed a higher consistency with the mass loss after decay than TEA; higher mass loss was more stringently reflected by higher heat production rate. Heat production did not proceed linearly, possibly due to the inhibition of fungal activity by an excess of carbon dioxide

Numerical investigation of the bodywork effect (K-effect)

Add-on armour kits composed of high-hardness steel plates are often used to improve the protection of light personnel carriers and logistic vehicles against the ballistic impact of small caliber ammunition, such as the 5,56×45 mm and the 7,62×51 mm NATO Ball projectiles. The protective kits are integrated inside the existing vehicle bodywork. There are indications, however, that the overall ballistic protection can also become less efficient by using the add-on armour, especially for the 5,56×45 mm threat. This phenomenon is referred to as the bodywork effect: the ballistic protection offered by the bodywork plate in combination with the additional armour plate is lower than the protection offered by the armour plate alone. This paper investigates the origin of the bodywork effect through a series of numerical simulations. For validation purposes, a limited number of firings have been performed. Split Hopkinson pressure bars tests were used for the characterization of the dynamic behaviour of the integrated armour plate material

Numerical and experimental study of the impact of small caliber projectiles on ballistic soap

Terminal ballistic deals with interactions between targets and projectiles. One of the areas of interest is wound ballistics, where one studies the interaction between a projectile (a bullet or a fragment) and the human body. Soap and gelatin are commonly used materials for simulating soft human body tissue in wound ballistics experiments. They are to be considered as tools for comparing the effectiveness of different projectiles. The department of weapon systems & ballistics of the Belgian Royal Military Academy is examining to what extent the Autodyn hydrocode can be used as a numerical tool for simulating the penetration of military bullets into ballistic soap. This article presents the philosophy and the results of the project's first phase i.e. the use of Autodyn for simulating the penetration of a steel sphere into a block of ballistic soap as a result of a normal impact at different velocities. A series of experiments (real firings) have been performed in the laboratory of the department. They serve as a reference and validation tool for the numerical approach. The latter is characterized by the specific problem of accurate material modeling of the soap. The application of a stepwise parametric study of material models and parameters has resulted in numerical simulations which fit quite well with experiments

Numerical and experimental study of the impact of small caliber projectiles on ballistic soap

In previous studies [1, 2], an elastoplastic model for soap material has been considered to characterize the soap behavior under impacts of spherical bullets. The characterization and validation of this model were made via the deceleration of a bullet into the soap material. In order to take into account the strain hardening and strain rate effects, an investigation of an elastoviscoplastic model is made. For model characterization purposes, experimental data were obtained from the viscoelastic Hopkinson pressure bar. The model parameters were determined through an optimization process and validation of the model was done by using a series of firing tests from previous experiments where spherical bullets were fired into soap blocks [1, 2]