Optimization and characterization of tungsten thick coatings on copper based ally substrates

Tungsten is a promising armour material for plasma facing components of nuclear fusion reactors because of its low sputter rate and favourable thermo-mechanical properties. Among all the techniques able to realise W armours, plasma spray looks particularly attractive owing to its simplicity and low cost. The present work concerns the optimisation of spraying parameters aimed at 4–5 mm thickWcoating on copper–chromium–zirconium (Cu,Cr,Zr) alloy substrates. Characterisation of coatings was performed in order to assess microstructure, impurity content, density, tensile strength, adhesion strength, thermal conductivity and thermal expansion coefficient. The work performed has demonstrated the feasibility of thick W coatings on flat and curved geometries. These coatings appear as a reliable armour for medium heat flux plasma facing component

Polygonal surfaces in pseudo-hyperbolic spaces

A polygonal surface in the pseudo-hyperbolic space H^(2,n) is a complete maximal surface bounded by a lightlike polygon in the Einstein universe Ein^(1,n) with finitely many vertices. In this article, we give several characterizations of them. Polygonal surfaces are characterized by finiteness of their total curvature and by asymptotic flatness. They have parabolic type and polynomial quartic differential. Our result relies on a comparison between three ideal boundaries associated with a maximal surface, corresponding to three distinct distances naturally defined on the maximal surface.Comment: Main Theorem modified, 45 pages, 7 figure

Development of a multi-scale methodology for composite structural modelling and validation of modelling procedure by mechanical testing - Final Report

Objectives of the work are to develop a multiscale methodology for composite structural modelling and to validate the modelling procedure by mechanical testing. In the field of the computational material science the multiscale methodology plays an important role. It is based on the hierarchical concept which recognises that there is a strong interconnection between phenomena which happen to different scales of length and time. In the field of the composite material the approach consists in the description of the ply by knowing the behaviour of the constituents, i.e. fibre and matrix. In this work was developed a constitutive model for a balanced plain weave fabric. This model, starting from geometrical parameters and mechanical parameters of the single constituents (fibre and matrix), determines the effective moduli of the representative unit cell (RUC). This model was implemented into a general purpose finite element program ABAQUS, building a specific user subroutine. The last part of this job was to determine a material failure mechanism theory for the balanced plain weave architecture that was implemented in the same specific user subroutine. The prediction of the failure at each increment of the load was obtained by using a quadratic failure criterion, applied to the strains with stiffness and strength reduction scheme to account for damage within the yarns. This standard user subroutine is an augmentation for any commercial finite element code giving the possibility to deal with any composite material made with balanced plain weave fabric, knowing the mechanical properties of the single constituents and the specific failure mechanism

La comunicazione del bene in Platone

The interpretation of the idea of the good in Plato takes advantage of the analysis of the literary representation of communication of good in the Platonic dialogues, in particular in the Symposium and Republic

Effectiveness Comparison Between Young Leaf Extracts Acacia nilotica with Desmanthus virgatus Against Vermicidal Potency of Haemonchus contortus In-vitro

Acacia nillotica and Desmanthus virgatus are two entopharmacologycal plants that thrives throughout the season in East Nusa Tenggara Province, other Provinces in Indonesia or tropical countries. Extraction of young leaves of Acacia nillotica (EDMAN) and Desmanthus virgatus (EDMDV) contains tannin compound. By pharmacodynamic viewpoint, this extraction has potency as an anthelmintic. Objective: to compare the in-vitro effectivity of young leaves extraction of the two plants as a vermicidal power to combat Haemonchus contortus. Materials: young leaves of Acacia nillotica and Desmanthus virgatus and Haemonchus contortus. Method: The study was grouped into four treatments: EDMAN, EDMDV, Positive control (Albendazole 0,055%) and negative control (aquades).  The concentration of the young leaves extracts are 2.5%, 3.5%, 4.5% out of 0.01 g/mL of extraction. Each treatment was applied to 6 female Haemonchus contortus with four replicates allowing immersion time for 1, 3, 5 or 7 hours. Variable measured and tested was mortality of the H. contortus. The vermicidal effectively was descriptively analysed. The results showed that mortality percentage (vermicidal) treatment of 2.5%, 3.5%, 4.5% EDMAN for 7-hour immersion was 16.7%, 45.8%, 12.5%, respectively. That values for EDMDV for similar concentrations and immersion time was 50%, 33.3%, 12.5%, respectively. Conclusion: EDMDV has a more effective vermicidal power between the two etnopharmacological treatments at 2.5% concentration

Indentatore piano cilindrico per la caratterizzazione meccanica dei materiali metallici: sviluppi sperimentali e simulazioni

Recenti sviluppi tecnologici hanno portato alla disponibilità di macchine sperimentali per eseguire prove strumentate di indentazione profonda. Tali macchine consentono di misurare in modo continuo la variazione del carico di indentazione come funzione della profondità di indentazione. La prova di indentazione è usata per investigare il comportamento elasto-plastico dei materiali metallici. Questa prova è tecnicamente più semplici della prova di trazione, ma la corretta interpretazione fisica del processo di deformazione che avviene durante la penetrazione è molto complesso, perché il campo delle tensioni sotto l’indentatore è multiassiale e inomogeneo. Il presente lavoro costituisce una continuazione di un’attività che vede il dipartimento di Ingegneria dei Materiali dell’Universita degli studi di Roma “Tor Vergata” importante artefice e tratta dello sviluppo di un indentatore portatile che consente di applicare carichi fino a circa 2000_N con sensibilità di 4_N e di raggiungere penetrazioni di 1_mm con sensibilità di 1_μm. Tale macchina nasce come sviluppo del dispositivo FIMEC (Flat-top cylinder Indenter for MEchanical Characterization) che utilizza un indentatore cilindrico a testa piatta del diametro di 1_mm al fine di generare curve carico-penetrazione da cui ricavare le caratteristiche meccaniche quali il carico di snervamento, il modulo di Young e informazioni circa il comportamento plastico del materiale. La possibilità attraverso studi teorici e computazionali di chiarire la meccanica del contatto e i meccanismi della deformazione al fine di estrarre sistematicamente le proprietà meccaniche dei materiali dalle curve di carico-penetrazione aprono interessanti sviluppi sulla caratterizzazione delle proprietà dei materiali metallici tra cui quelli utilizzati nella fusione nucleare. La semplicità della macchina sperimentale consente il suo impiego anche su particolari meccanici già realizzati, montati ed in servizio. La costruzione di un modello matematico per la soluzione del problema diretto dell’indentazione con penetratore cilindrico cioè il metodo di determinare la curva di indentazione per un penetratore cilindrico partendo dalle caratteristiche elasto-plastiche del materiale, costituisce la parte più originale del lavoro di simulazione. Tale lavoro ha permesso di sviluppare un modello per la soluzione del problema inverso dell’indentazione con penetratore cilindrico cioè il metodo di ricavare le proprietà elasto–plastiche di un materiale partendo dalla curva di indentazione ottenuta con un penetratore cilindrico. Le prove sperimentali di indentazione a freddo sono state integrate con prove di indentazione a caldo grazie alla realizzazione di un apposito forno per il riscaldamento dei campioni, si sono inoltre eseguite prove di creep di indentazione confermando la possibilità che i parametri della prova di creep per trazione a carico costante possono essere determinati da una prova di creep di indentazione.Recent technological advances have led to the general availability of depth sensing instrumented indentation, where the indenter penetration force can be continuously monitored as a function of the depth of penetration into a substrate during both loading and unloading. Indentation tests are often used for the investigation of elasto-plastic mechanical behaviour of materials. These tests are technically simpler than the tensile test, but the correct physical interpretation of the deformation process taking place during impression tests is very intricate, because the stress field under the intender is multiaxial and inhomogeneous. The present work constitutes a continuation of an activity that sees the department of Engineering of the materials of the University of studies in Rome “Tor Vergata” important maker and it deals the development of a portable indenter that allows to apply load up to 2000_N with sensitiveness of 4_N and to reach penetrations of 1_mm with sensitiveness of 1_ μm. Such a machine is born how development of the device FIMEC (Flat-top cylinder Indenter for MEchanical Characterization) that uses a flat cylindrical indenter of the diameter of 1_mm with the purpose of generating load-penetration curves from which to extract the mechanical characteristics as the yield strength, the Young’s modulus and the information about the plastic behaviour of the material. Comprehensive theoretical and computational studies have emerged to elucidate the contact mechanics and the deformation mechanisms in order to systematically extract material properties from load-penetration curves obtained from instrumented indentation. The simplicity of the experimental machine allows its use also on fulfilled mechanical details, already mounted and in service. The construction of a mathematical model for the solution of the forward analysis leads to prediction of the force-penetration response from known elasto-plastic properties. The development of this forward analysis algorithm constitutes the most original part of the work of simulation. Such work has let to develop a model for the solution of the reverse analysis of the indentation with cylindrical indenter. The reverse analysis implies estimation of the elasto-plastic properties from a complete (i.e., loading and full unloading) load-penetration curve. The experimental tests of indentation made at room temperature have been integrated with tests at high temperature using a special oven for heating the samples. Indentation creep testing were carried out in order to present an experimental validated method to determine the material creep parameters (usually get from the uniaxial tensile tests) from the indentation creep tests

Analisis Strategi Guru dalam Meningkatkan Motivasi Belajar Peserta Didik SMP Negeri 2 Gunungsitoli

This research is motivated by the attitude of students who are very actively involved and motivated in learning activities. Therefore, the objectives of carrying out this research are: (1) To find out teacher strategies in increasing students' learning motivation in class VIII science subjects at SMP Negeri 2 Gunungsitoli. (2) To determine the supporting and inhibiting factors in increasing the learning motivation of students in class VIII science subjects at SMP Negeri 2 Gunungsitoli. The type of research used is qualitative research with a descriptive approach. The research location is at SMP Negeri 2 Gunungsitoli. The research population is class VIII students in the 2023/2024 academic year. Research instruments, namely: observation sheets, questionnaires and interviews. Research results: (1) Teacher strategies in increasing students' learning motivation are: making students actively involved in learning, choosing appropriate learning methods, creating a pleasant learning atmosphere, giving challenging assignments to students, giving awards, and appreciating success learners. (2) Supporting factors in increasing students' learning motivation are the enthusiasm for learning and curiosity of students in learning, the completeness of learning facilities and infrastructure, the attitude of teachers who have a work ethic as professional teachers. Meanwhile, the inhibiting factors in increasing students' learning motivation are when students lack focus in participating in learning activities, lack of facilities and infrastructure to support learning, and monotonous teaching strategies that are unpleasant. According to the research results, it can be concluded that if a teacher has developed a good and interesting teaching strategy, it will definitely be able to increase students' learning motivation.&nbsp

L’Ospedale neuropsichiatrico di Arezzo: aspetti istituzionali e archivistici

L’approccio archivistico allo studio della storia della psichiatria in Italia è stato di grande importanza, avendo consentito un precoce interesse verso il recupero di materiali documentari a rischio di dispersione con l’applicazione della ‘legge Basaglia’. Nell’articolo, dopo un bilancio storiografico in tema di conservazione di archivi di istituti psichiatrici, viene affrontato il caso dell’ospedale neuropsichiatrico aretino, delineandone la dimensione istituzionale dai primi studi di fattibilità di fine Ottocento sino alla sua piena efficienza nel corso del XX secolo. Definite quindi le prassi burocratiche adottate nell’istituto e le modalità di produzione, conservazione e trasmissione del materiale documentario, sono evidenziate le fonti che consentono di approfondire lo studio dell’atelier di pittura in esso approntato, sia analizzando le tipologie documentarie oggi presenti nell’archivio storico dell’ospedale, sia estendendo lo sguardo a quanto recuperabile presso soggetti privati.The archival approach to the study of the history of psychiatry in Italy was of great importance, having allowed an early interest in the recovery of documentary materials at risk of dispersion by the application of the ‘Basaglia law’. In the article, after a historiographical assessment on the subject of conservation of archives of psychiatric institutions, the case of the Arezzo neuropsychiatric hospital is addressed, outlining its institutional dimension from the first studies at the end of the XIX century up to its full efficiency during the XX century. Having defined the bureaucratic practices adopted in the institute and the methods of production, conservation and transmission of documentary material, the sources are highlighted which allow us to deepen the study of the painting atelier set up there, both by analyzing the documentary typologies present today in the historical archive of the hospital, and by extending the research to what can be recovered from private entities

Comparative analyses of Mikania (Asteraceae: Eupatorieae) plastomes and impact of data partitioning and inference methods on phylogenetic relationships

We assembled new plastomes of 19 species of Mikania and of Ageratina fastigiata, Litothamnus nitidus, and Stevia collina, all belonging to tribe Eupatorieae (Asteraceae). We analyzed the structure and content of the assembled plastomes and used the newly generated sequences to infer phylogenetic relationships and study the effects of different data partitions and inference methods on the topologies. Most phylogenetic studies with plastomes ignore that processes like recombination and biparental inheritance can occur in this organelle, using the whole genome as a single locus. Our study sought to compare this approach with multispecies coalescent methods that assume that different parts of the genome evolve at different rates. We found that the overall gene content, structure, and orientation are very conserved in all plastomes of the studied species. As observed in other Asteraceae, the 22 plastomes assembled here contain two nested inversions in the LSC region. The plastomes show similar length and the same gene content. The two most variable regions within Mikania are rpl32-ndhF and rpl16-rps3, while the three genes with the highest percentage of variable sites are ycf1, rpoA, and psbT. We generated six phylogenetic trees using concatenated maximum likelihood and multispecies coalescent methods and three data partitions: coding and non-coding sequences and both combined. All trees strongly support that the sampled Mikania species form a monophyletic group, which is further subdivided into three clades. The internal relationships within each clade are sensitive to the data partitioning and inference methods employed. The trees resulting from concatenated analysis are more similar among each other than to the correspondent tree generated with the same data partition but a different method. The multispecies coalescent analysis indicate a high level of incongruence between species and gene trees. The lack of resolution and congruence among trees can be explained by the sparse sampling (~ 0.45% of the currently accepted species) and by the low number of informative characters present in the sequences. Our study sheds light into the impact of data partitioning and methods over phylogenetic resolution and brings relevant information for the study of Mikania diversity and evolution, as well as for the Asteraceae family as a whole