Composite Laminates under Dynamic Extreme Conditions

AbstractGlass fibre laminates were subjected to experimental low velocity impact tests at three different temperatures, room, T = -25°C, T = -50°C, and the results were compared to investigate the impact behaviour in extreme conditions of composites applied in naval field. The experiments were carried out, first, at complete penetration of the specimens and then, at different energy values to investigate on the damage initiation and propagation. The indentation depths and the delaminated areas were measured and analyzed to validate existing semiempirical models for the prediction of the response of these materials in dynamic shock conditions, at the aim to help the navigation in the Artic Ocean in safety conditions

An agile approach for IS/IT benefits management

Doutoramento em GestãoInvestments in Information Systems and Information Technology (IS/IT) by organizations around the world have been increasing, as the competition grows fierce. Despite this increase, many organizations feel that their investments do not get the return they expected in terms of real benefits to the business. There have been several attempts to create methods to improve the success of the investments of organizations in the implementation of IS/IT and methodologies have been devised for this purpose, although with modest improvements. One of the main methodologies is the Benefits Management methodology created in the University of Cranfield, widely recognized as a great methodology with proven results, although its adoption is not as high as it would be expected and desirable. This research project looks at the published literature to find the reasons for this problem and then, resorting to Design Science Research methodology, creates artefacts aiming to help solving some of the known problems in the adoption of the Benefits Management methodology. The created artefacts, as defined by the Design Science Research methodology, were then evaluated with a case study that took place in a large Portuguese bank. The results of the evaluation indicate that the artefacts created during this research project were useful and helpful for the adoption of the Benefits Management methodology created in the University of Cranfield.Os investimentos em Sistemas de Informação e em Tecnologia da Informação (IS/IT) por parte das organizações em todo o mundo têm aumentado, à medida que a concorrência cresce ferozmente. Apesar desse aumento, muitas organizações sentem que seus investimentos não lhes trazem o retorno esperado em termos de reais benefícios para o negócio. Têm havido diversas tentativas para criar métodos para melhorar o sucesso dos investimentos das organizações na implementação de IS/IT e foram concebidas metodologias para esse fim, embora com modestas melhorias. Uma das principais metodologias é a metodologia de Gestão de Benefícios criada na Universidade de Cranfield, amplamente reconhecida como uma excelente metodologia, com resultados comprovados, muito embora a sua taxa de adoção não seja tão alta quanto seria expectável e desejável. Este projeto de investigação examina a literatura publicada, procurando encontrar os motivos desse problema e, em seguida, recorrendo à metodologia Design Science Research, cria artefactos com o objetivo de ajudar a resolver alguns dos problemas conhecidos na adoção da metodologia de Gestão de Benefícios. Os artefactos criados, conforme definido pela metodologia Design Science Research, foram depois avaliados num Estudo de Caso que decorreu num grande banco português. Os resultados da avaliação indicam que os artefactos criados durante este projeto de investigação são úteis e ajudam à adoção da metodologia de Gestão de Benefícios criada na Universidade de Cranfield.N/

optimization of solar integration in biomass fuelled steam plants

Abstract This paper is focused on solar-biomass integration and presents a thermodynamic analysis of solar power utilization replacing the steam bleeds of a regenerative Hirn cycle plant, biomass fuelled, in feedwater pre heating process. In solar-biomass integrated configuration an energy conversion efficiency of solar energy has been evaluated in order to compare the use of solar energy in solo and hybrid configurations. Such efficiency has been adopted as optimization parameter for the best hybrid plant configuration, varying steam pressure and regeneration parameters

Natural zeolites and white wines from Campania region (Southern Italy): a new contribution for solving some oenological problems

The purpose of this research is to provide a new mixture of Campanian zeolitized tuffs for solving two specific problems in the production of white wines: the protein and tartaric stability. In fact, a very frequent cause of turbidity and formation of organic deposits in white wines is the occurrence of thermolabile and thermostable proteins colloidal suspensions which precipitate in time, especially in summertime and during the storage and transport. Normally, to mitigate this risk wine producers use organic and inorganic stabilizers and clarifiers. The best known treatment, recognized also by the International Organisation of Vine and Wine (OIV) foresees the use of bentonite with a montmorillonite content not lower than 80%. The present paper aims at evaluating the use of two high zeolite grade Italian volcanoclastites such as the Neapolitan Yellow Tuff (NYT) and the Yellow Facies of the Campanian Ignimbrite (YFCI), in the treatment of three peculiar white wines of the Campanian region (Southern Italy): Falanghina, Fiano di Avellino and Greco di Tufo. Granulates were produced starting from tuff blocks as provided by quarries. Some grain size fractions have been prepared to investigate the zeolite content (phillipsite + chabazite + analcime) by X-ray diffraction (XRD). A 2-5 mm grain size fraction was chosen for NYT and a 5-10 mm for YFCI. Three Campanian monocultivar white wines were used for the test: the Falanghina 2006 vintage, the Fiano di Avellino DOCG 2007 vintage, and the Greco di Tufo DOCG 2008 vintage. 48 samples with mixture of the zeolitized tuffs, 1 sample with mixture of a synthetic zeolite A and 1 sample with mixture of a commercial sodium activated bentonite were prepared. ICP-OES analysis for the determination of ECEC, Ion Chromatography (IC) analyses for the determination of some major cations and Turbidimetric tests for the definition of the protein stabilization process before and after treatments were also carried out. It was evidenced that high zeolitized tuff/wine ratios enable the protein stabilization whereas a significant decrease of potassium ion after the treatment with a zeolite-rich powder improves the tartaric stability, a serious problem in all the wine productions. The results of these tests refer to a laboratory scale research. A transfer of the experiment to a pilot plant scale is in progress

Verbi locativi in italiano come varianti di verbi supporto

In questo articolo discuteremo la nozione di "carrier verbs" (secondo la definizione del linguista americano Zellig Harris) o di "light verbs" (come denominata all'inizio del XX secolo da Otto Jespersen). La nostra cornice teorica è rappresentata dal lessico-grammatica di Maurice Gross, una teoria iniziata negli anni settanta a partire dalla sintassi del francese sulle basi matematiche già individuate per la lingua inglese da Zellig Harris. In particolare, discuteremo di come alcuni verbi locativi dell'italiano possano essere usati come verbi supporto (secondo la definizione data da Gross dei "light verbs" harrisiani) e assumano il ruolo sintattico una volta attribuito dai grammatici greci e latini alla copula esse.En aquest article discutirem la noció de "carrier verbs" (segons la definició del lingüista americà Zellig Harris) o de "light verbs" (segons la denominació que Otto Jespersen n'havia donat a principi del segle XX). El nostre marc teòric de referència és el lèxic-gramàtica de Maurice Gross, una teoria començada els anys setanta a partir de la sintaxi del francès en les bases matemàtiques ja individuades per a la llengua anglesa per Zelling Harris. Concretament, tractarem de com alguns verbs locatius de l'italià es poden emprar com a verbs de suport (tal com Gross va definir els "light verbs" harrisians) i de com assumeixen el paper sintàctic que els gramàtics grecs i llatins atribuïen a la còpula esse.In this article we aim at discussing the notion of carrier verbs (according to the definition provided by the American linguist Zellig Harris) or of light verbs (as defined at the beginning of the twentieth century by Otto Jespersen). Our theoretical framework is represented by Maurice Gross' lexicon-grammar, a theory developed during the seventies on the French syntax and directly inspired by Zellig Harris' mathematical grammar of English. Particularly, we are going to discuss of how some Italian locative verbs can be used as support verbs (according to the definition which Maurice Gross has given of the harrisian light verbs) and can play the syntactic role traditionally given to the copula esse by the Greek and Latin grammarians

AURA_ A MEDIA DEVICE FOR NEW NARRATION SPACES IN MUSEUM CONTEXTS

The long months of social distance to which the pandemic has forced us have certainly accelerated the idea that the remediation of the concept of distance in a digital horizon can open up new spaces of negotiation for many social and cultural practices in the future. But it has also, dramatically, highlighted the limits and risks contained in the very idea that the experience of the meta-universe can really do without the mediation of physical reality and human direct intervention. The reflections and design experience proposed here therefore aim to reflect on the role that the new technologies and traditional professionals are playing in relation with the phygital cultural experience. The idea of the contemporary museum is indagated, questioning, however, the quality of the 'relationship' between the work of art and the user and the ways in which design can respond creatively to the demand for cultural consumption by activating new processes of attribution of meaning

Damage and energy absorption in GFRP laminates impacted at low-velocity: Indentation model

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Advanced Image Analysis of Two-Phase Flow inside a Centrifugal Pump

The analysis two-phase flow inside centrifugal pumps is a fundamental issue in several engineering applications. This often represents a bad working condition with respect to single phase one, causing head reduction, efficiency decrease, and higher operational costs in terms of energy and money. The paper reports a numerical analysis of bubbles behavior inside centrifugal pumps. Equations regulating the air bubble motion within the rotor of a centrifugal pump have been solved considering the effects of all forces acting. Coalescence phenomena have been investigated too, in order to identify how gas zone presence in the rotor can lead to anomalous working condition. Results are reported in graphs and diagrams varying bubble dimension and water flow rate. An experimental approach to visualize the two-phase flow field inside the impeller is presented too. Images have been acquired, elaborated, compared with numerical results, and discussed in order to understand the interaction between gas phase and liquid phase and to correlate this behavior with the energy dissipation phenomena for a centrifugal pump

Dynamic-Mechanical Behaviour of Bio-composites☆

Abstract PLA-hemp bio-composites with different reinforcement content were manufactured by compression moulding process. Both flexural and impact properties were investigated and compared to the unreinforced polymer. In addition, also the creep behaviour adopting the Arrhenius theory was determined, in order to better understand the industrial application limits of PLA reinforced by natural fibres. For this purpose, DMA tests were carried out, in order to evaluate the activation energy and to apply the Time-Temperature Superposition model to the compliance curves obtained by short-time creep tests

Numerical, Experimental and Analytical Correlation for Predicting the Structural Behavior of Composite Structures under Impact

Abstract In the present work, numerical, experimental and analytical results regarding impact events on composite structure are presented. The test case consists in a classic 24 plies CAI specimen (100×150 mm) subjected to 10 J impact. The work can be divided into two phases. The first phase is finalized to the definition of a procedure able to provide a robust numerical model, which can simulate accurately the structural response of composite plates subjected to impact events. At this phase, the numerical results are compared with analytical ones. In the second phase, both inter- and intra-lamina failure are considered. Regarding the inter-laminar failure, an experimental-numerical procedure is defined in order to set the right parameters related to cohesive behaviour. For both phases, trade-off analyses on the main numerical parameters are performed. All numerical results are compared with experimental ones in terms of both energy balance and damaged area