Economy and Ecology: Encounters and Interweaving

In this editorial text, we point to the importance and development of disciplines that closely link economic sciences with ecology. Drawing on the most important literature in these fields, we have highlighted the trends that are popular today in both fields (double eco features)

Residents’ perceptions of wine tourism on the rural destinations development

Purpose – The purpose of this paper is to study the impact of wine tourism on rural destination development. Consequently, this study attempts to develop contemporary insights on this under-researched area such as residents’ perceptions of wine tourism and its impact on the rural destination development. Design/methodology/approach – In this study, the authors used a structured survey questionnaire from a random sample of 318 respondents based on the Fruška Gora Mountain in Serbia. Research also used structural equational modeling for empirical econometric testing in this data sample. This technique is appropriate for multivariate analysis. Findings – Personal resident benefit associated with wineries is positively related to resident perceived economic impact (H1) R2 ¼ 0.624; socio-cultural impact (H2) R2 ¼ 0.685 and environmental impact (H3) R2 ¼ 0.716 of wineries on local communities. Looking at the path diagram, the authors concluded that personal resident benefit associated with wineries is strongly related to resident perceived impact of wineries on local communities as regression weights are higher. Other findings relate those residents’ positive perceptions of wine tourism to increases in sales revenue, environmental protection, intrapersonal and interpersonal communication. Research limitations/implications – The positive attitude of the local population is an essential link of development. Such understanding of residents’ perceptions optimizes destination management in the future and, more importantly, local sustainable development. This has high policy implications. Originality/value – The present study contributes to the scientific circles by connecting perception research with wine tourism

New materials for stereolithography 3D printing

It is the dream of every engineer to be able to design unrestrained by the limitations of conventional manufacturing and assembly. The technology of 3D printing brings those dreams at our fingertips, but is curtailed by the lack of materials that are appropriate for functional use. In the case of stereolithography 3D printing, the photocurable epoxy resin currently used is unstable under sunlight and is mechanically weak. Sunlight can excite currently-used photo initiators compelling 3D printed parts to continue to polymerize, making it unstable. Further, epoxy resins are categorically weak due to its poor network structure. Here, I introduce metal oxide semiconducting nanoparticles as a new class of initiators for epoxy photopolymerization. I demonstrate that the crystal structure of the semiconducting nanoparticles significantly affects the reaction kinetics of epoxy photopolymerization. I illustrate that the TiO2(B) crystal structure, that was never observed before in flame-made titania, doubles the rate of epoxy photopolymerization relative to P25 titania, the gold standard for photocatalysis. The bandgap energy of metal oxide semiconducting nanoparticles can easily be controlled by selecting from a myriad of various standard materials and controlling their crystal size taking advantage of their quantized effect. Thus, I also demonstrate the ability to synthesize silica-embedded quantum dots using the industrially established technology of flame spray pyrolysis. Finally, I also demonstrate that graphene oxide liquid crystals can be photocured into a paper-like macroscopic structure with comparable mechanical properties to benchmark samples prepared according to the literature. This thesis contributes distinct steps towards photostable and strong stereolithography 3D printing resin

Photocuring epoxy with quantum dots for 3D printing

3D printing is the future of manufacturing, limited by material development. Stereolithography is an ideal 3D printing process as it is energy efficient, accurate, fast and capable of forming composite materials. The photocuring of polymers used in this process is integral to society via more applications such as dentistry, coating, and printed circuit boards. However, those photosensitive materials are unstable in daylight during end use limiting their viability for making functional parts in many applications, motivating our work. The ultimate goal is to photocure only with light outside of the solar spectrum on Earth in stereolithography 3D printing, which motivates this work, to produce photostable parts. While semiconducting nanoparticles have previously been shown to photocure acrylic resins via a free radical mechanism, here we demonstrate, for the first time, that semiconducting nanoparticles are capable of photocuring epoxy cationically. This result is critical because with that achieved, the quantized effect can be used to increase the band gap energy of the nanoparticles to only be sensitive to light outside of the solar spectrum on Earth. We study both bulk and quantized nanoparticles, propose a reaction mechanism supported by experimental observations, and explore the effects of process variables on the kinetics of the reaction. The intertwining of the engineering of the application, the chemistry of the reactions and the physics of quantum dots makes this thesis a truly rich, interdisciplinary study

Multi-scenario modelling of learning

International audienceDesigning an educational scenario is a sensitive and challenging activity because it is the vector of learning. However, the designed scenario may not correspond to some learners’ characteristics (pace of work, cognitive styles, emotional factors, prerequisite knowledge, …). To personalize the learning task and adapt it gradually to each learner, several scenarios are needed. Adaptation and personalization are difficult because it is necessary on the one hand to know in advance the profiles and on the other hand to produce the multiple scenarios corresponding to these profiles. Our model allows to design many scenarios without knowing the learner profiles beforehand. Furthermore, it offers each learner opportunities to choose a scenario and to change it during their learning process. The model ensures that all announced objectives have enough resources for acquiring knowledge and activities for evaluation

Noncommutative Geometry Framework and The Feynman's Proof of Maxwell Equations

The main focus of the present work is to study the Feynman's proof of the Maxwell equations using the NC geometry framework. To accomplish this task, we consider two kinds of noncommutativity formulations going along the same lines as Feynman's approach. This allows us to go beyond the standard case and discover non-trivial results. In fact, while the first formulation gives rise to the static Maxwell equations, the second formulation is based on the following assumption $m[x_{j},\dot{x_{k}}]=i\hbar \delta_{jk}+im\theta_{jk}f.$ The results extracted from the second formulation are more significant since they are associated to a non trivial $\theta$-extension of the Bianchi-set of Maxwell equations. We find $div_{\theta}B=\eta_{\theta}$ and $\frac{\partial B_{s}}{\partial t}+\epsilon_{kjs}\frac{\partial E_{j}}{\partial x_{k}}=A_{1}\frac{d^{2}f}{dt^{2}}+A_{2}\frac{df}{dt}+A_{3},$ where $\eta_{\theta}$, $A_{1}$, $A_{2}$ and $A_{3}$ are local functions depending on the NC $\theta$-parameter. The novelty of this proof in the NC space is revealed notably at the level of the corrections brought to the previous Maxwell equations. These corrections correspond essentially to the possibility of existence of magnetic charges sources that we can associate to the magnetic monopole since $div_{\theta}B=\eta_{\theta}$ is not vanishing in general.Comment: LaTeX file, 16 page

Isolated right atrial appendage (RAA) rupture in blunt trauma – a case report and an anatomic study comparing RAA and right atrium (RA) wall thickness

BACKGROUND: Heart chambers rupture in blunt trauma is uncommon and is associated with a high mortality. The determinant factors, and the incidence of isolated heart chambers rupture remains undetermined. Isolated rupture of the right atrium appendage (RAA) is very rare, with 8 cases reported in the reviewed literature. The thin wall of the RAA has been presumed to render this chamber more prone to rupture in blunt trauma. OBJECTIVE: To report a case of isolated RAA rupture in blunt trauma, and to compare right atrium (RA) and RAA wall thickness in a necropsy study. METHODS: The thickness of RA and RAA wall of hearts from cadavers of fatal penetrating head trauma victims was measured. Our case of isolated RAA rupture is presented. The main findings of the 8 cases reported in the literature, and the findings of our case, were organized in a table. RESULT: The comparison of the data showed that wall thickness of the RAA (0.53 ± 0.33 mm) was significantly thinner than that of RA (1.11 ± 0.42 mm) (p < 0.05). COMMENTS: In all these 9 cases of isolated RAA rupture, cardiac tamponade occurred, RAA rupture was diagnosed intraoperatively and sutured, and the patients survived. Main mechanisms hypothesized for heart chamber rupture include mechanical compression coincident with phases of cardiac cycle, leading to high hydrostatic pressure inside the chamber. Published series include numerous cases of RA rupture, and only a few cases of RAA rupture. CONCLUSION: Thus, our data suggests that wall thickness is not a determinant factor for RA or RAA rupture in blunt trauma

UWB through-the-Wall Propagation

The propagation of ultrawideband (UWB) signals in indoor environments is an important issue with significant impacts on the future direction and scope of UWB technology. The propagation of UWB signals is governed, among other things, by the properties of materials in the propagation medium. The information on electromagnetic properties of construction materials in the UWB frequency range would provide valuable insights into the appreciation of the capabilities and limitations of UWB technology. Although electromagnetic properties of certain construction materials over relatively narrow bandwidths in GHz frequency ranges are available, ultrawideband characterisation of most typical construction materials for UWB communication purposes has not been reported. In narrowband wireless communications, only the magnitude of insertion loss has been the quantity of interest. But for UWB signals, in addition to the magnitude, the phase information is an equally important factor that needs to be accounted for. In fact, UWB signals not only suffer attenuation when propagating through walls, but also suffer distortion due to the dispersive properties of the walls. This research examines propagation through typical construction materials and their ultrawideband characterisation. Ten commonly used construction materials are chosen for this investigation. Results for the dielectric constant and loss tangent of the materials over the UWB frequency range are presented. Accuracy of the measured results is discussed and distortions of UWB signals due to the dispersive properties of wall materials are addressed

UWB through-the-Wall Propagation

The propagation of ultrawideband (UWB) signals in indoor environments is an important issue with significant impacts on the future direction and scope of UWB technology. The propagation of UWB signals is governed, among other things, by the properties of materials in the propagation medium. The information on electromagnetic properties of construction materials in the UWB frequency range would provide valuable insights into the appreciation of the capabilities and limitations of UWB technology. Although electromagnetic properties of certain construction materials over relatively narrow bandwidths in GHz frequency ranges are available, ultrawideband characterisation of most typical construction materials for UWB communication purposes has not been reported. In narrowband wireless communications, only the magnitude of insertion loss has been the quantity of interest. But for UWB signals, in addition to the magnitude, the phase information is an equally important factor that needs to be accounted for. In fact, UWB signals not only suffer attenuation when propagating through walls, but also suffer distortion due to the dispersive properties of the walls. This research examines propagation through typical construction materials and their ultrawideband characterisation. Ten commonly used construction materials are chosen for this investigation. Results for the dielectric constant and loss tangent of the materials over the UWB frequency range are presented. Accuracy of the measured results is discussed and distortions of UWB signals due to the dispersive properties of wall materials are addressed