400 research outputs found

    The evaluation of buildings energy consumption and the optimization of district heating networks: a GIS-based model

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    The European buildings occupy a key place among the major energy consumer sectors, with high savings potential. The development of urban planning tools helpful to understand the right policy strategies turning the settled sustainable targets into real energy consumption savings is now a real challenge. Into this paper is described a methodology, for the mid-long term scenarios analysis, able to asses the buildings energy consumption of a municipality by means of a simulation approach and of a geo-referenced characterization of the stock. A thermal model, based on real consumption data, has been used to evaluate space heating energy demand; different savings opportunities have been simulated. Moreover, from the geo-referenced representation of the district heating network, through the integrated procedure, it is possible to perform the optimization of the network layout. A case study application in Turin is presented. Main results are the evaluation of energy consumptions, total costs of the interventions and the release of policy suggestions. Thanks to geo-referenced maps is allowed to put in evidence criticalities and policy effects through thematic maps. The methodology highlights the advantages of coupling a geographical information system application and energy demand forecasting model to build up a tool aimed at supporting decision-making

    Investigating in vivo Brain Metabolite Levels in Concussed Female Athletes and a Murine Model of Repetitive Closed Head Injury

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    After a concussion there is a complex cascade of events, termed the neurometabolic cascade, that includes changes in ion flux, neurotransmission, and cellular energetics. How this pathophysiological process translates into cognitive deficits remains poorly understood. Magnetic resonance spectroscopy (MRS) provides a non-invasive technique that allows for the quantification of brain metabolites that are involved in these processes, including glutamate and glutamine, which are involved in neurotransmission. Moreover, female athletes are underrepresented in studies on concussion, limiting our knowledge and understanding of sex differences. The overall goal of this thesis was to examine metabolite changes using MRS in female athletes before and after concussion, with the added goal of quantifying glutamate and glutamine separately. The second objective was to replicate metabolite changes in an animal model of concussion, to position future studies to probe the reasons for these changes, and to explore whether these changes represent potential therapeutic targets. MRS was acquired from the prefrontal WM of female athletes (contact and non-contact sports) and sedentary women at 3T to explore metabolite differences between groups and changes after concussion. In addition, an animal model of repeated closed head impacts was studied at 9.4T, in an effort to replicate the findings observed in humans. In the contact athlete cohort, reduced glutamine and glutamine/total creatine (Gln/Cr) were found following concussion, and after a season of play in non-concussed athletes. In the non-contact athlete cohort, metabolite levels did not change over the course of a season, and they did not differ from age matched sedentary women, except for a small difference in myo-inositol. Most interestingly, glutamine levels were significantly elevated in contact athletes compared to sedentary and non-contact groups, suggesting that sub-concussive impacts may have a long-term effect on brain metabolite levels. Furthermore, the large difference in glutamine levels between contact and non-contact athletes has implications in study design in regards to control groups versus test-retest paradigm. In the final study, we used a murine model (C57BL6) of repeated closed head injury to investigate metabolite level changes post-injury. Elevated Gln/Cr was observed 10-weeks post-injury, suggesting that the model may be appropriate to study sub-concussive injury. Together, these studies suggest that there exists a cumulative effect on the brain from sub-concussive impacts in contact sports, that manifests as elevated glutamine levels. Moreover, concussion in the same cohort of athletes results in reduced glutamine levels. Further work aimed at replicating these findings in animal models will be crucial to understanding the effects of cumulative impacts and concussion

    Induced ferroelectric phases in TbMn_2O_5

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    The magnetostructural transitions and magnetoelectric effects reported in TbMn2O5 are described theoretically and shown to correspond to two essentially different mechanisms for the induced ferroelectricity. The incommensurate and commensurate phases observed between 38 and 24 K exhibit a hybrid pseudoproper ferroelectric nature resulting from an effective bilinear coupling of the polarization with the antiferromagnetic order parameter. This explains the high sensitivity of the dielectric properties of the material under applied magnetic field. Below 24 K the incommensurate phase shows a standard improper ferroelectric character induced by the coupling of two distinct magnetic order parameters. The complex dielectric behavior observed in the material reflects the crossover from one to the other transition regime. The temperature dependences of the pertinent physical quantities are worked out, and previous theoretical models are discussed

    3D printed splint designed by 3D surface scanner for patients with hand allodynia.

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    Allodynia is a neuropathic pain triggered by a normally painless stimulus: for example, a slight touch on the skin or slight sensation of hot or cold is extremely painful. Rehabilitation is long and uncertain. Protecting the painful area from stimuli is a priority of care. This type of care is complex and challenging for the care team: the pain caused in manufacturing a classic molded orthosis is unbearable for the patient, and the orthosis has a limited lifetime, and experience shows that it is not possible to produce two identical splints. The present study consisted in creating protective splints by 3D printing, designed from data collected with the 3D surface scanner used in our forensic imaging and anthropology unit. The pros and cons of the 3D orthosis versus standard molded orthoses from the point of view of the patient and the practitioner are discussed, with evaluation of related indications of this technology

    Finite strain Landau theory of high pressure phase transformations

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    The properties of materials near structural phase transitions are often successfully described in the framework of Landau theory. While the focus is usually on phase transitions, which are induced by temperature changes approaching a critical temperature T-c, here we will discuss structural phase transformations driven by high hydrostatic pressure, as they are of major importance for understanding processes in the interior of the earth. Since at very high pressures the deformations of a material are generally very large, one needs to apply a fully nonlinear description taking physical as well as geometrical nonlinearities (finite strains) into account. In particular it is necessary to retune conventional Landau theory to describe such phase transitions. In Troster et al (2002 Phys. Rev. Lett. 88 55503) we constructed a Landau-type free energy based on an order parameter part, an order parameter-(finite) strain coupling and a nonlinear elastic term. This model provides an excellent and efficient framework for the systematic study of phase transformations for a wide range of materials up to ultrahigh pressures

    Antiferrodistortive phase transition in EuTiO3

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    X-ray diffraction, dynamical mechanical analysis and infrared reflectivity studies revealed an antiferrodistortive phase transition in EuTiO3 ceramics. Near 300K the perovskite structure changes from cubic Pm-3m to tetragonal I4/mcm due to antiphase tilting of oxygen octahedra along the c axis (a0a0c- in Glazer notation). The phase transition is analogous to SrTiO3. However, some ceramics as well as single crystals of EuTiO3 show different infrared reflectivity spectra bringing evidence of a different crystal structure. In such samples electron diffraction revealed an incommensurate tetragonal structure with modulation wavevector q ~ 0.38 a*. Extra phonons in samples with modulated structure are activated in the IR spectra due to folding of the Brillouin zone. We propose that defects like Eu3+ and oxygen vacancies strongly influence the temperature of the phase transition to antiferrodistortive phase as well as the tendency to incommensurate modulation in EuTiO3.Comment: PRB, in pres

    Confinement effects on glass forming liquids probed by DMA

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    Many molecular glass forming liquids show a shift of the glass transition T-g to lower temperatures when the liquid is confined into mesoporous host matrices. Two contrary explanations for this effect are given in literature: First, confinement induced acceleration of the dynamics of the molecules leads to an effective downshift of T-g increasing with decreasing pore size. Second, due to thermal mismatch between the liquid and the surrounding host matrix, negative pressure develops inside the pores with decreasing temperature, which also shifts T-g to lower temperatures. Here we present dynamic mechanical analysis measurements of the glass forming liquid salol in Vycor and Gelsil with pore sizes of d=2.6, 5.0 and 7.5 nm. The dynamic complex elastic susceptibility data can be consistently described with the assumption of two relaxation processes inside the pores: A surface induced slowed down relaxation due to interaction with rough pore interfaces and a second relaxation within the core of the pores. This core relaxation time is reduced with decreasing pore size d, leading to a downshift of T-g proportional to 1/d in perfect agreement with recent differential scanning calorimetry (DSC) measurements. Thermal expansion measurements of empty and salol filled mesoporous samples revealed that the contribution of negative pressure to the downshift of T-g is small (<30%) and the main effect is due to the suppression of dynamically correlated regions of size xi when the pore size xi approaches

    Measuring pelvises in 3D surface scans and in MDCT generated virtual environment: Considerations for applications in the forensic context.

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    Virtual Anthropology (VA) transposes the traditional methods of physical anthropology to virtual environments using imaging techniques and exploits imaging technologies to devise new methodological protocols. In this research, we investigate whether the measurements used in the Diagnose Sexuelle Probabiliste (DSP) and Ischio-Pubic Index (IPI) differ significantly when 3D models of a bone are generated using 3D surface scans (3DSS) and Multidetector Computed Tomography (MDCT) scans. Thirty pelvises were selected from the SIMON identified skeletal collection. An equal ratio of females to males was sought, as well as a good preservation of the bones. The pelvises were scanned using an MDCT scanner and a 3D surface scanner. The measurements of the DSP and IPI methods on the dry bones (referred to as macroscopic measurements here), and then to the 3D models. The intra- and interobserver, using the Technical Error of Measurement (TEM) and relative Technical Error of Measurement (rTEM) error was assessed, and we aimed to observe if the measurements made on the MDCT and 3DSS generated models were significantly different from those taken on the dry bones. Additionally, the normality of the data was tested (Shapiro-Wilk test) and the differences in measurements was evaluated using parametric (Student t-tests) and non-parametric (Wilcoxon) tests. The TEM and rTEM calculations show high intra and interobserver consistency in general. However, some measurements present insufficient inter- and intraobserver agreement. Student t and Wilcoxon tests indicate potentially significant differences of some measurements between the different environments. The results show that especially in the virtual environment, it is not easy to find the right angle for some of the DSP measurements, However, when comparing the measurement differences between dry and virtual bones, the results show that most of the differences are less than or equal to 2.5 mm. Considering the IPI, the landmarks are already difficult to determine on the dry bone, but they are even more difficult to locate in the virtual environment. Nevertheless, this study shows that quantitative methods may be better suited for application in the virtual environment, but further research using different methods is needed
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