Modelling, control and testing of internal combustion engines to minimize consumption and pollutant emissions

The objective of the PhD thesis was to research technologies and strategies to reduce fuel consumption and pollutants emission produced by internal combustion engines. In order to meet this objective my activity was focused on the research of advanced controls based on cylinder pressure feedback. These types of control strategies were studied because they present promising results in terms of engine efficiency enhancement. In the PhD dissertation two study cases are presented. The first case is relative to a control strategy to be used at the test bench for the optimisation of the spark advance calibration of motorcycle Engine. The second case is relative to a control strategy to be used directly on board of mining engines with the objective or reducing the engine consumption and correct ageing effects. In both cases the strategies proved to be effective but their implementation required the use of specific toolchains for the measure of the cylinder pressure feedback that for a matter of cost makes feasible the strategy use only for applications: • At test bench • In small-markets like large off-road engines The major bottleneck that prevents the implementation of these strategies on mass production is the cost of cylinder pressure sensor. In order to tackle this issue, during the PhD research, the development of a low-cost sensor for the estimation of cylinder pressure was studied. The prototype was a piezo-electric washer designed to replace the standard spark-plug washer or high-pressure fuel injectors gasket. From the data analysis emerged the possibility to use the piezo-electric prototype signal to evaluate with accuracy several combustion metrics compatible for the implementation of advanced control strategies in on-board applications. Overall, the research shows that advanced combustion controls are feasible and beneficial, not only at the test bench or on stationary engines, but also in mass-produced engines.

Vaginal immunology and microbiome composition: bacterial vaginosis in a macaque model

Nonhuman primates (NHPs) are important animal models for the study of human health and disease. In particular, the use of NHPs to study the vaginal microbiome and susceptibility to infections (such as HIV and herpesvirus) is exceptionally valuable due to the similarity in anatomy and physiology. An important aspect to this is maintaining a healthy vaginal microbiome which then minimizes colonization by pathogens and resulting inflammation along the mucosa. In women, conditions such as bacterial vaginosis (BV) are frequently treated with antibiotics such as metronidazole or clindamycin. Due to the excessive use of antimicrobials in medicine and agriculture, alternative compounds and therapies are highly desired to treat infections. Approaches that have been developed and used for vaginal infections includes the use of natural antimicrobials such as essential oils, probiotics, and live cultures, which mimic and function like antibiotics but lack development of resistance like classic antibiotics. However, these approaches have been minimally studied in humans and animals. Effectiveness of essential oils are anecdotal at best. Microbiome manipulation on the other hand has been investigated more thoroughly. Novel products are being distributed for medical use and are monotherapies containing Lactobacillus which colonize the vaginal mucosa (Ali et al., 2020; Brichacek et al., 2013; Lagenaur, Sanders-Beer, et al., 2011). Unfortunately, these therapies have limitations due to durability and individual response in women. By evaluating the extent by which the NHP vaginal mucosa can be colonized with exogenously delivered bacteria, this animal model will highlight the NHP for use in translational studies which use essential oils and beneficial microbiome bacteria for vaginal delivery.

New associations between native parasitoids and exotic insects introduced in Italy and in Europe

The introduction of exotic species is one of the most important threats to biodiversity.This phenomenon may cause economic and environmental damage. To prevent these invasions there are institutions like EPPO. Nevertheless, the introduction of exotic pests is an increasing issue, difficult to control. Classic biological control, based on importation of natural enemies from the country of origin, has been successfully used for over 120 years, but it has also raised some criticism. My research work has focused on the study of the new associations occurring between indigenous parasitoids and three exotic pests introduced in Italy and Europe. The three target insects considered were: Cacyreus marshalli Butler (Lepidoptera: Lycaenidae), a pest of Geranium plants; Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), a plague of Castanea sp. and Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae). This ladybug has been introduced as a biological control agent, but since some years it considered as an invasive species. For C. marshalli I performed laboratory tests on acceptance and suitability of immature stages of this butterfly by Exorista larvarum (Diptera: Tachinidae) and Brachymeria tibialis (Hymenoptera: Chalcidicae). The experiments showed that these two parasitoids could be used to contain this pest. For D. kuriphilus I performed field samplings in an infested chestnut area, the samples were maintained in rearing chamber until gall wasp or parasitoids emergence. In the 3-year research many parasitoids of gall wasps were found; one of these, Torymus flavipes (Walker), was found in large number. For H. axyridis the research work included a first phase of field sampling, during which I searched indigenous parasitoids which had adapted to this new host; the only species found was Dinocampus coccinellae (Schrank) (Hymenoptera: Braconidae). Laboratory tests were performed on the wasp rearing, biology and capacity to contain H. axyridis.

Can gut microbiota analysis be beneficial for ex-situ and in-situ conservation of threatened animal species?

Ex-situ conservation and the in-situ conservation of natural habitats are the tools to conserve biodiversity. Habitats and ecosystems have been becoming altered by human activities and a growing number of species requires form of management to ensure their survival. Conservation queries become more complex and urgent. Developing scientifically based and innovative approaches to ex-situ conservation is necessary. Recent studies underline importance of gut microbiome in animal health with implications for animal conservation and management. Animal and human studies have demonstrated that environmental factors can impact gut microbiome composition. Within this scenario, the present work focused on species belonging to different taxa, reptiles and mammals: Aldabrachelys gigantea, the giant tortoise of the Seychelles islands and Indri indri, the greatest leaving lemur of Madagascar. The Seychelles giant tortoise is vulnerable species with declining population, whereas the indri is a critically endangered species that could reach the extinction within 25 years. Both need research to help them to survive. Tortoises live for very long time and to observe how they can afford the environmental changes is very difficult. Indris, instead, are able to survive only in a small area of the Madagascar forest, with a very strong link between the species’ survival and the environment. The obtained results underline importance of environmental factors, both in-situ and ex-situ, for species conservation. Microbiome could help the organisms to respond on a short timescale and cope with, environmental changes. However, species with long generation time might not be able to adapt to fast changes but bacteria with a short generation time can adapt on a shorter timescale allowing the host to cope with fluctuating environment. Gut microbiome plays an important role in an animal’s health and has the potential to improve the management of individuals under human care for conservation purposes.