2,412 research outputs found

    On Damage Identification in Planar Frames of Arbitrary Size

    Get PDF
    Framed structures are deeply studied in civil engineering since they provide a numerical model for the analysis of the static and dynamic response of multi-storey buildings. In order to evaluate the vibrational properties of these structures, an eigen-problem, which involves the stiffness and mass matrices of the frame, must be solved. Both matrices can be assembled by means of standard methods, which take into account the numbers of degrees of freedom of the frame. The occurrence of concentrated damage in some vulnerable sections modifies the degrees of freedom and therefore both the stiffness and mass matrices. Very often, the critical sections are located in the joints between the structural elements of the frame where the bending moment reaches its maximum value. Assuming that the joints are rigid in the undamaged configuration of the frame, it is possible to take into account their loss of stiffness due to the presence of eventual damage by means of hinges with rotational springs of variable rigidity. In this paper, an original algorithm that allows us to evaluate the stiffness and mass matrices and therefore the natural frequencies of vibration of undamaged and damaged planar frames with an arbitrary number of beams and columns is presented. The proposed algorithm for the stiffness and mass matrices determination requires a few input data which can be provided in a text file and therefore allows us to speed up the procedure with respect to the application of an FEM approach which requires the construction of single models for each considered frame. The results obtained by means of the proposed algorithm have been validated through a comparison with those provided by an FEM model implemented in SAP2000. The natural frequencies obtained by means of the proposed approach are used for the solution of two different inverse problems, which concern the identification of, respectively, the mechanical characteristics of the constitutive material and the location and intensity of the damage. Both the proposed identification procedures deal with optimization algorithms that are based on opportune fitness functions. Applications to frames of different size confirm the validity of the presented identification algorithms. Furthermore, an iterative procedure, able to reduce the required computational burden related to the identification of the location and intensity of damage, is presented and applied in a parametric study concerning frames with increasing size

    Cittadinanza digitale e sostenibilità. Un’esperienza di apprendimento online realizzata in una scuola primaria

    Get PDF
    Nel presente contributo si riportano la progettazione e la descrizione di un’esperienza di apprendimento online, che ha coinvolto una classe prima di una scuola primaria nella provincia di Bari e in cui si intrecciano l’Educazione allo Sviluppo Sostenibile e l’Educazione alla Cittadinanza Digitale. La scuola si pone, infatti, come il luogo in cui educare a una digital citizenship e rendere i cittadini del domani in grado di mettere in atto delle soluzioni verdi – ambientaliste – e blu – digitali – (Floridi, 2020), poiché la tecnologia non è solo causa di problematiche di sostenibilità, ma può essa stessa divenire una soluzione a tali problematiche (Valera, 2012)

    Storytelling digitale e educazione al patrimonio immateriale: una revisione descrittiva

    Get PDF
    Il presente contributo intende esplorare la relazione che intercorre tra la metodologia del digital storytelling e la valorizzazione del patrimonio culturale immateriale nell’ambito della formazione ed educazione. Da un’attenta analisi della letteratura scientifica sull’argomento ci si aspetta di comprendere se il digital storytelling possa essere un’efficace metodologia nei contesti di apprendimento formale per sviluppare il senso di appartenenza alla comunità, portando ad un riconoscimento e alla valorizzazione del patrimonio culturale immateriale locale

    Cittadinanza digitale e sostenibilità. Un’esperienza di apprendimento online realizzata in una scuola primaria

    Get PDF
    In this paper, we report the design and description of an online learning experience. It involves the first class of a primary school in the province of Bari. The focus of this path is the connection between Education for Sustainable Development and Education for Digital Citizenship. The school should educate to a digital citizenship and make the citizens of tomorrow able to implement green solutions – environmentalists – and blue – digital – (Floridi, 2020). In fact, technology is not only the cause of sustainability issues, but at the same time it is a solution to these issues (Valera, 2012).Nel presente contributo si riportano la progettazione e la descrizione di un’esperienza di apprendimento online, che ha coinvolto una classe prima di una scuola primaria nella provincia di Bari e in cui si intrecciano l’Educazione allo Sviluppo Sostenibile e l’Educazione alla Cittadinanza Digitale. La scuola si pone, infatti, come il luogo in cui educare a una digital citizenship e rendere i cittadini del domani in grado di mettere in atto delle soluzioni verdi – ambientaliste – e blu – digitali – (Floridi, 2020), poiché la tecnologia non è solo causa di problematiche di sostenibilità, ma può essa stessa divenire una soluzione a tali problematiche (Valera, 2012)

    Analysis of Lanthanum and Cobalt Leaching Aimed at Effective Recycling Strategies of Solid Oxide Cells

    Get PDF
    Lanthanum and cobalt are Critical Raw Materials and components of Solid Oxide Cells— SOCs electrodes. This review analyses lanthanum and cobalt leaching from waste materials (e-waste, batteries, spent catalysts), aiming to provide a starting point for SOC recycling, not yet investigated. The literature was surveyed with a specific interest for leaching, the first phase of hydrometallurgy recycling. Most references (86%) were published after 2012, with an interest higher (85%) for cobalt. Inorganic acids were the prevailing (>80%) leaching agents, particularly for lanthanum, while leaching processes using organic acids mostly involved cobalt. The experimental conditions adopted more diluted organic acids (median 0.55Mfor lanthanum and 1.4Mfor cobalt) compared to inorganic acids (median value 2 M for both metals). Organic acids required a higher solid to liquid ratio (200 g/L), compared to inorganic ones (100 g/L) to solubilize lanthanum, while the opposite happened for cobalt (20 vs. 50 g/L). The process temperature didn’t change considerably with the solvent (45–75  C for lanthanum, and 75–88  C for cobalt). The contact time was higher for lanthanum than for cobalt (median 3–4 h vs. 75–85 min). Specific recycling processes are crucial to support SOCs value chain in Europe, and this review can help define the existing challenges and future perspectives

    Metacognition as a predictor of improvements in personality disorders

    Get PDF
    Personality Disorders (PDs) are particularly hard to treat and treatment drop-out rates are high. Several authors have agreed that psychotherapy is more successful when it focuses on the core of personality pathology. For this reason, therapists dealing with PDs need to understand the psychopathological variables that characterize this pathology and exactly what contributes to maintaining psychopathological processes. Moreover, several authors have noted that one key problem that characterizes all PDs is an impairment in understanding mental states - here termed metacognition - which could also be responsible for therapy failures. Unfortunately, a limited number of studies have investigated the role of mentalization in the process of change during psychotherapy. In this paper, we assume that poor metacognition corresponds to a core element of the general pathology of personality, impacts a series of clinical variables, generates symptoms and interpersonal problems, and causes treatment to be slower and less effective. We explored whether changes in metacognition predicted an improvement among different psychopathological variables characterizing PDs; 193 outpatients were treated at the Third Center of Cognitive Psychotherapy in Rome, Italy, and followed a structured path tailored for the different psychopathological variables that emerged from a comprehensive psychodiagnostic assessment that considered patients' symptoms, metacognitive abilities, interpersonal relationships, personality psychopathology, and global functioning. The measurements were repeated after a year of treatment. The results showed that changes in metacognitive abilities predicted improvements in the analyzed variable

    Bacterial stimuli activate nitric oxide colonic mucosal production in diverticular disease. Protective effects ofL. casei DGÂź (Lactobacillus paracaseiCNCM I-1572)

    Get PDF
    Background: Micro-inflammation and changes in gut microbiota may play a role in the pathogenesis of diverticular disease (DD). Objective: The objective of this article is to evaluate the expression of nitric oxide (NO)-related mediators and S100B in colonic mucosa of patients with DD in an ex vivo model of bacterial infection. Methods: Intestinal biopsies obtained from patients with diverticulosis, symptomatic uncomplicated diverticular disease (SUDD) and SUDD with previous acute diverticulitis (SUDD+AD) were stimulated with the probiotic L. casei DGÂź (LCDG) and/or the pathogen enteroinvasive Escherichia coli (EIEC). S100B, NO release and iNOS expression were then evaluated. Results: Basal iNOS expression was significantly increased in SUDD and SUDD+AD patients. Basal NO expression was significantly increased in SUDD+AD. No differences in S100B release were found. In all groups, iNOS expression was significantly increased by EIEC and reduced by LCDG. In all groups, except for SUDD+AD, EIEC significantly increased NO release, whereas no increase was observed when LCDG was added to biopsies. EIEC did not induce significant changes in S100B release. Conclusions: Colonic mucosa of patients with DD is characterized by a different reactivity toward pathogenic stimuli. LCDG plays a role in counteracting the pro-inflammatory effects exerted by EIEC, suggesting a beneficial role of this probiotic in DD

    Monitoring of hadrontherapy treatments by means of charged particle detection

    Get PDF
    The interaction of the incoming beam radiation with the patient body in hadrontherapy treatments produces secondary charged and neutral particles, whose detection can be used for monitoring purposes and to perform an on-line check of beam particle range. In the context of ion-therapy with active scanning, charged particles are potentially attractive since they can be easily tracked with a high efficiency, in presence of a relatively low background contamination. In order to verify the possibility of exploiting this approach for in-beam monitoring in ion-therapy, and to guide the design of specific detectors, both simulations and experimental tests are being performed with ion beams impinging on simple homogeneous tissue-like targets (PMMA). From these studies, a resolution of the order of few millimeters on the single track has been proven to be sufficient to exploit charged particle tracking for monitoring purposes, preserving the precision achievable on longitudinal shape. The results obtained so far show that the measurement of charged particles can be successfully implemented in a technology capable of monitoring both the dose profile and the position of the Bragg peak inside the target and finally lead to the design of a novel profile detector. Crucial aspects to be considered are the detector positioning, to be optimized in order to maximize the available statistics, and the capability of accounting for the multiple scattering interactions undergone by the charged fragments along their exit path from the patient body. The experimental results collected up to now are also valuable for the validation of Monte Carlo simulation software tools and their implementation in Treatment Planning Software packages

    Diagnosis of anal human papillomavirus infection: polymerase chain reaction or cytology?

    Get PDF
    Summary Objectives To investigate the relationship between human immunodeficiency virus (HIV)-positive and HIV-negative patients engaging in promiscuous behaviors and anal human papillomavirus (HPV) infection diagnosed by polymerase chain reaction (PCR) and cytology. Methods Fifty-six HIV-positive patients and 49 HIV-negative patients who engaged in sexually promiscuous behavior were enrolled in the study. We performed cytological exams using the Pap smear and PCR for HPV-DNA detection, with identification of oncogenic strains. The 2001 Bethesda System terminology was used for the cytological exams. We also evaluated the immunologic status of the HIV-infected patients. Results PCR positivity for HPV-DNA was higher in the group of HIV-positive patients than in the group of HIV-negative patients with a statistically significant difference. In contrast we did not find any statistically significant difference by cytological exam. Oncogenic strains were equally distributed in the two groups. Conclusions Our results indicate the importance of the cytological exam for anal HPV screening in the population at high risk of sexually transmitted disease and that HPV-DNA PCR can be used only as adjunct test
    • 

    corecore