186 research outputs found

    The influence of the net rainfall mixed Curve Number – Green Ampt procedure in flood hazard mapping: a case study in Central Italy

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    A net rainfall estimation procedure, referred to as Curve-Number For Green-Ampt (CN4GA), combining the Soil Conservation Service - Curve Number (SCS-CN) method and the Green and Ampt (GA) infiltration equation was recently developed, aiming to distribute at subdaily time resolution the information provided by the SCS-CN method. The initial abstraction and the total volume of rainfall provided by the SCS-CN method are used to identify the ponding time and to quantify the hydraulic conductivity parameter of the GA equation, whereas the GA infiltration model distributes the total volume of the rainfall excess provided by the SCS-CN method. In this study we evaluate the proposed procedure with reference to a real case comparing the flood mapping obtained applying the event-based approach for two different net rainfall scenarios: the proposed CN4GA and the common SCS-CN. Results underline that the net rainfall estimation step can affect the final flood mapping result

    Design of Mechanical Properties of Poly(butylene-adipate-terephthalate) Reinforced with Zein-TiO2 Complex

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    Mechanical properties of polymer biocomposites are influenced by the interaction between thematrix and the filler surface. In this work, composites based on poly(butylene-adipate-terephthalate) (PBAT) filled with micrometric particles of zein-TiO2 complex (ZTC) were realized via solvent casting technique at different concentrations, equal to 0, 5, 10, and 20 wt%. After pelletization, the resulting materials were injection molded into standard specimens, employed for the uniaxial tensile test (UTT) characterization. From the stress-strain curves, Young’s modulus (E), yield stress (σy), stress at break (σB), elongation at break (εB), and toughness (T) were collected. The addition of the ZTC proved to show a reinforcing effect on the polymeric matrix, with an increase in both E and σy. Modelling of the mechanical properties was performed by applying Kerner’s and Pukánszky’s equations. Kerner’s model, applied on experimental E values, returned a very good correspondence between collected and theoretical values. From the application of Pukánszky’s model to σy, the obtained B value showed a good interfacial interaction between the matrix and the filler. Due to the enhanced stiffness of the composites, a reduction in the true stress at break (σT,B) was observed. The modified Pukánszky’s model gave a B value lower than the one obtained for the yield, but still in the range of acceptable values for microcomposites

    Preparation and Characterisation of PBAT-Based Biocomposite Materials Reinforced by Protein Complex Microparticles

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    In this work, new biodegradable composite materials based on poly (butylene adipate terephthalate) (PBAT) reinforced with zein–TiO2 complex microparticles were prepared and characterised by electron microscopy and tensile and dynamic-mechanical tests. The composite pellets were prepared by solvent casting with different filler contents, namely 0, 5.3, 11.1 and 25 part per hundred resin (phr), to modify and modulate the properties of the final materials. Scanning electron microscopy (SEM) images showed homogeneous dispersion of the filler, without microparticles aggregation or phase separation between filler and matrix, suggesting a good interphase adhesion. According to tensile tests, Young’s modulus showed an improvement in the rigidity and the yield stress presented an increasing trend, with opposite behaviour compared to other composites. Dynamic-mechanical analysis (DMA) results exhibited increasing storage modulus values, confirming a greater rigidity with a higher filler percentage. The glass transition temperature showed a slightly increasing trend, meaning the presence of an interaction between the two phases of the composite materials. Overall, the produced PBAT composites showed similar properties to low-density polyethylene (LDPE), proving to be promising and more sustainable alternatives to traditional polymers commonly adopted in agri-food fields

    Flexible PBAT-Based Composite Filaments for Tunable FDM 3D Printing

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    Biobased composites with peculiar properties offer an attractive route for producing environmentally friendly materials. The reinforcement for poly(butylene adipate-co-terephthalate) (PBAT), based on zein-titanium dioxide (TiO2) complex (ZTC) microparticles, is presented and used to produce composite filaments, successfully 3-dimensionally (3D) printed by fused deposition modeling (FDM). The outcome of ZTC addition, ranging from 5 to 40 wt %, on the thermo-mechanical properties of composite materials was analyzed. Results reveal that storage modulus increased with increasing the ZTC content, leading to a slight increase in the glass transition temperature. The creep compliance varies with the ZTC concentration, denoting a better resistance to deformation under constant stress conditions for composites with higher complex content. Scanning electron microscopy was used to assess the quality of interphase adhesion between PBAT and ZTC, showing good dispersion and distribution of complex microparticles in the polymer matrix. Infrared spectroscopy confirmed the formation of a valid interface due to the formation of hydrogen bonds between filler and polymer matrix. Preliminary tests on the biocompatibility of these materials were also performed, showing no cytotoxic effects on cell viability. Finally, the 3D printability of biobased composites was demonstrated by realizing complex structures with a commercial FDM printer

    Tunable FDM 3D printing of flexible poly(butylene adipate terephthalate)-based biocomposite filaments

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    Poly(butylene adipate-co-terephthalate), PBAT, is a synthetic and 100% biodegradable polymer based on fossil resources, with high elongation at break and high flexibility. These properties are comparable to lowdensity polyethylene, making PBAT a very promising biodegradable material that could replace it in some industrial applications. However, its lower mechanical properties have limited its application range. The reinforcement of PBAT with rigid filler, such as zein-TiO2 (ZTC) complex microparticles, has the purpose to expand its application fields, from the food and agricultural packaging to healthcare sector. The 3D printability of bio-based composites was demonstrated by realizing complex structures with a commercial FDM printer

    Um estudo sobre o ensino de Matemática a alunos com deficiência em escolas na província de Buenos Aires

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    This work presents the results of a research about the teaching of Mathematics to students with disability. It articulates contributions from the Didactics of Mathematics and Inclusive Education. This is a study that collects information on possible ways of recognizing heterogeneity and differences in mathematics classrooms.  Different lines of research were developed within our project. Here, we will refer to only two of them. The first line of research dealt with the analysis of forms of teaching and didactic conceptions that are present in special education classrooms; and the second one dealt with experiences, possibilities and obstacles that teachers identify in the planning and development of their Mathematics classes in schools attended jointly by students with and without disability.  This paper presents the analysis of episodes of Mathematics classes and interviews, as well as math curriculum and teacher training programs. Finally, we share considerations and new questions that are being studied in our current studies.  Different lines of research were developed within our project. Here, we will refer to only two of them. The first line of research dealt with the analysis of  forms of teaching and didactic conceptions that are present in special education classrooms; and the second one dealt with  experiences, possibilities and obstacles that teachers identify in the planning and development of their Mathematics classes in schools attended jointly by students with and without disability. This paper presents the analysis of episodes of Mathematics classes and interviews, as well as math curriculum and teacher training programs. Finally, we share considerations and new questions that are being studied in our current studies.Este trabajo presenta resultados de una investigación sobre la enseñanza de las matemáticas a alumnos con discapacidad, articulando aportes de la didáctica de la matemática y de la educación inclusiva. Se trata de un estudio que releva información sobre formas posibles de reconocer la heterogeneidad y las diferencias en aulas de matemática.  Al interior del proyecto se desplegaron diferentes líneas de investigación; aquí solo se hará referencia a dos de ellas. La primera buscó analizar formas de enseñanza y concepciones didácticas vigentes en aulas de educación especial, y la segunda, indagar experiencias, posibilidades y obstáculos que los docentes identifican en la planificación y desarrollo de clases de matemática en aulas de escuelas comunes a las que asisten alumnos con y sin discapacidad.  Este escrito presenta el análisis de episodios de clases de matemática y de entrevistas, así como también de diseños curriculares y programas de formación docente. Para finalizar, se comparten reflexiones y nuevos interrogantes que se abordan en estudios actuales. O presente trabalho apresenta os resultados de uma investigação sobre o ensino de Matemática para alunos com deficiência, articulando contribuições da Didática da Matemática e da Educação Inclusiva. Este é um estudo que coleta informação sobre as possíveis maneiras de reconhecer a heterogeneidade e às diferenças nas salas de aula de Matemática.  Diferentes linhas de pesquisa foram implantadas no projeto; apenas duas delas serão mencionados aqui. A primeira buscou analisar formas de ensino e concepções didáticas vigentes nas salas de aula de educação especial; a segunda, investigar experiências, possibilidades e obstáculos que os professores identificam no planejamento e desenvolvimento das aulas de Matemática nas salas de aula de escolas comuns frequentadas pelos alunos com e sem deficiência.  Este artigo apresenta a análise de episódios de aulas de Matemática e entrevistas, bem como desenhos curriculares e programas de treinamento de professores. Finalmente, são compartilhadas reflexões e novas questões abordadas nos estudos atuais.

    Skull Base Fungal Osteomyelitis: A Case Report and Review of the Literature

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    Skull base osteomyelitis (SBO) is an invasive infection refractory to therapy, closely linked with malignant otitis externa (MOE). It is characterized by a mild clinical presentation that can delay cross-sectional imaging considered as the key to revealing it. Skull base osteomyelitis typically affects elderly diabetics and immunocompromised patients (>70 years). It most commonly has an otogenic origin due to an extension of MOE. The prognosis can be very poor without the administration of adequate and timely therapy at an early disease stage. Nowadays, Pseudomonas aeruginosa remains the most common pathogen associated with SBO. Fungi are a rare cause of MOE. This report documents a rare case of otogenic SBO caused by Candida parapsilosis in a diabetic patient, with persistent otologic symptoms as clinical onset and resistance to medical treatment. Fungal MOE has more subtle symptoms and is more aggressive than its bacterial counterpart. When MOE is resistant to antibacterial drugs, this should raise the suspicion of a fungal etiology of MOE. The current guidelines do not exhaustively describe the diagnosis, antifungal drugs of choice, and optimum duration of treatment. The description of these rare clinical cases should help with the multidisciplinary management of this disease in order to optimize the diagnosis and therapeutic protocol

    Prognostic Value of Whole-Body PET Volumetric Parameters Extracted from 68Ga-DOTATOC PET/CT in Well-Differentiated Neuroendocrine Tumors

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    Our objective was to evaluate the prognostic value of somatostatin receptor tumor burden on Ga-68-DOTATOC PET/CT in patients with well-differentiated (WD) neuroendocrine tumors (NETs). Methods: We retrospectively analyzed the 68Ga-DOTATOC PET/CT scans of 84 patients with histologically confirmed WD NETs (51 grade 1, 30 grade 2, and 3 grade 3). For each PET/CT scan, all Ga-68-DOTATO-Cavid lesions were independently segmented by 2 operators using a customized threshold based on the healthy liver SUVmax (LIFEx, version 5.1). Somatostatin receptor-expressing tumor volume (SRETV) and total lesion somatostatin receptor expression (TLSRE = SRETV X SUVmean) were extracted for each lesion, and then whole-body SRETV and TLSRE (SRETVwb and TLSREwb, respectively) were defined as the sum of SRETV and TLSRE, respectively, for all segmented lesions in each patient. Time to progression (TTP) was defined as the combination of disease-free survival in patients undergoing curative surgery (n = 10) and progression-free survival for patients with unresectable or metastatic disease (n = 74). TTP and overall survival were calculated by Kaplan-Meier analysis, log-rank testing, and the Cox proportional-hazards regression model. Results: After a median follow-up of 15.5 mo, disease progression was confirmed in 35 patients (41.7%) and 14 patients died. A higher SRETVwb (>39.1 cm(3)) and TLSREwb (>306.8 g) correlated significantly with a shortermedian TTP (12 mo vs. not reached; P < 0.001). In multivariate analysis, SRETVwb (P = 0.005) was the only independent predictor of TTP regardless of histopathologic grade and TNM staging. Conclusion: According to our results, SRETVwb and TLSREwb extracted from Ga-68-DOTATOC PET/CT could predict TTP or overall survival and might have important clinical utility in the management of patients with WD NETs
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