Design, Implementation and Verification of the Attitude Determination and Control Algorithms for the DelFFi Satellites

Space Systems EngineeringSpaceflightAerospace Engineerin

Blending of Hydrocarbon and Rosin Ester-basedResins to Study its Effect on the Physical andMechanical Properties of Thermoplastic Road Markings

In this study, the effect of hydrocarbon and rosin ester resins combination on the physical and mechanical properties of thermoplastic road markings were evaluated. At first, two basic thermoplastic road marking formulations based on hydrocarbon and rosin ester resins were prepared. Several samples of the blends of two basic formulations for thermoplastic road marking were characterized and compared by their softening points, abrasion resistance, color data changes, DMTA and tensile strength values. The results showed that hydrocarbon-based thermoplastic road markings have better weathering resistance and rosin ester based materials illustrated enhanced heat resistance. The inclusion of rosin ester thermoplastic road marking into the hydrocarbon-based formulations, improves compatibility of the hydrocarbon resin and dibutyl phthalate ()DBP)(, as well as their physical and mechanical properties. The unique properties of rosin arise from its hydrophobic chain skeleton and its hydrophilic carboxy groups which contribute to its excellent solubility and compatibility with a variety of other synthetic resins. The best performance was obtained with 50 wt % inclusion of rosin ester to hydrocarbon based compound. DMTA analysis revelation with combination of hydrocarbon and rosin ester-based road markings showed that the decreasing trend in elastic modulus is shifted to higher temperature, and as a result it keeps the hardness and ductile properties of thermoplastic road markings unchanged. More favored raw materials for compatibilization of compounds in road marking formulations lead to higher elongation- at-break and an increased toughness

Application of mixture experimental design to optimize formulation and performance of thermoplastic road markings

The influence offormulation components on the physical, mechanical and optical properties of hot melt thermoplastic road markings was studied. To minimize the number of experiments, mixture method was used as an effective tool for experimentaldesign. Binder (rosin ester and hydrocarbon based resins), pigment (TiO2), filler (talc) and plasticizer (long oil alkyd resin and dibutyl phthalate) were taken into consideration as the key factors at different levels. A range offormulations were prepared by melt blending of variables and other required components. Softening point temperature (Tsp) and its changes (ΔTsp), Taber abrasion resistance, color difference (ΔE) before and after exposure to the accelerated weathering conditions and heat stability test, were chosen as the key responses. A window of optimum end-use properties of thermoplastic road marking formulations was narrowed down within the range of desired responses in quadratic model using DX v.7.1.3 program. The results showed that the optimized formulations were very close to those from the regression analysis, and the mixture experimental design was an effectual method to optimize the composition of a thermoplastic road marking formulation with respect to its properties. The precision of the model was evaluated by preparing two samples in the optimized window and comparing the predicted and actual properties. The results showed a good agreement between the proposed model and experimental measurements

Increasing computing performance of ADCS subsystems in small satellites for earth observation

Space Systems EgineeringSpace Engineerin

Microglia, rather than bacterial factors, mediate bovine neutrophil chemotaxis in neurolisteriosis

Introduction: The bacterium Listeria monocytogenes (LM) can cause life-threatening central nervous system (CNS) infection (neurolisteriosis) in humans and ruminants. Polymorphonuclear neutrophils (PMNs) recruited into the CNS migrate to infectious foci to exert bacterial killing, but overzealous PMN recruitment is regularly linked to serious neural damage. Factors responsible for PMN chemotaxis to CNS infectious foci in neurolisteriosis remain obscure. Here, we aimed at identifying chemotactic factors (bacteria vs host-derived) for bovine PMNs in neurolisteriosis. Materials and methods: We performed ex-vivo chemotaxis assays with primary bovine PMNs to assess the chemotactic effect of LM components and supernatants of endogenous CNS cells infected with LM. IL-8 (main chemotactic candidate) expression was also assessed through ELISA and in-situ immunohistochemistry/immunofluorescence in CNS of naturally infected cattle. Results: Whole bacteria and LM cell wall components failed to elicit PMN chemotaxis, as did supernatants from LM-infected astrocytes and neural cells. Conversely, supernatant of LM-infected microglia proved chemotactic for PMNs. Moreover, microglial secretion of IL-8 was detected on in-vitro microglial infection and in microglia of cattle with neurolisteriosis in situ. Conclusions: Our results indicate that PMN chemotaxis to infectious foci in neurolisteriosis is independent of bacterial stimuli and is rather mediated by host-derived chemotactic factors (including IL-8) produced by microglia. Prevention of excessive PMN recruitment by blocking such factors may constitute a candidate therapeutic option to limit PMN-mediated CNS damage in neurolisteriosis

Pro-resolving lipid mediator lipoxin A4 attenuates neuro-inflammation by modulating T cell responses and modifies the spinal cord lipidome.

The chronic neuro-inflammatory character of multiple sclerosis (MS) suggests that the natural process to resolve inflammation is impaired. This protective process is orchestrated by specialized pro-resolving lipid mediators (SPMs), but to date, the role of SPMs in MS remains largely unknown. Here, we provide in vivo evidence that treatment with the SPM lipoxin A4 (LXA4) ameliorates clinical symptoms of experimental autoimmune encephalomyelitis (EAE) and inhibits CD4+ and CD8+ T cell infiltration into the central nervous system (CNS). Moreover, we show that LXA4 potently reduces encephalitogenic Th1 and Th17 effector functions, both in vivo and in isolated human T cells from healthy donors and patients with relapsing-remitting MS. Finally, we demonstrate that LXA4 affects the spinal cord lipidome by significantly reducing the levels of pro-inflammatory lipid mediators during EAE. Collectively, our findings provide mechanistic insight into LXA4-mediated amelioration of neuro-inflammation and highlight the potential clinical application of LXA4 for MS