Search results for " construction"

Can technical, functional and structural characteristics of dental units predict Legionella pneumophila and Pseudomonas aeruginosa contamination?

2011

Legionella pneumophila and Pseudomonas aeruginosa are common colonizers of water environments, particularly dental unit waterlines. The aim of this study was to assess whether the technical, functional and structural characteristics of dental units can influence the presence and the levels of opportunistic pathogens. Overall, 42 water samples were collected from dental units in a teaching hospital in Palermo, Italy, including 21 samples from the 21 taps supplied by the municipal water distribution system and 21 samples from oral rinsing cups at 21 dental units. L. pneumophila was present in 16 out of 21 water samples (76.2%) from dental units, and the median concentration was higher in samp…

Effects of Air Tightness Tests on Steel Thin-Wall Box Structures with Circular and Rectangular Cross Sections

2019

In this paper, the effects of air tightness tests on steel box structures with rectangular or circular cross sections typical of port cranes (legs, arms, and crosspieces) are analyzed. Legs and arms are generally made with elements with profiles having a square or rectangular cross section, while the diagonal struts are made with profiles having circular cross sections. To verify the air tightness of these elements, a necessary requirement to protect them from corrosion if they are not protected with other protection techniques, air tightness tests are performed. These tests, in the framework of durability tests, must be carried out while maintaining the structure elasticity well below the …

Byllis (Albanie) - Basilique B et annexes. Etude des liants de maçonnerie

2004

Techniques de construction traditionnelles et techniques romaines dans le théâtre d’Althiburos et les monuments de spectacle de l’Afrique Proconsulai…

2023

The contribution aims to study the relationship between the traditional construction techniques of the territories of Proconsular Africa and those imported by the Romans and used in the construction of entertainment buildings, in particular theaters and amphitheatres, also taking into account the importation of typological models, starting from the “case study” of the theater of Althiburos. During the 1st and 2nd centuries AD there is a gradual introduction of Roman construction techniques, such as the opus caemaenticium, especially in the construction of substructures and vaults, sometimes with the importation of urban models, of techniques but also of Italic workers (just think of the opu…

From C–S–H to C–A–S–H: Experimental study and thermodynamic modelling

2015

Abstract It has long been known that the stoichiometry of C–S–H varies with the calcium hydroxide concentration in solution. However, this issue is still far from understood. We revisit it in both experimental and modelling aspects. A careful analysis of the solubility confirms the existence of three different C–S–H phases, defined as Ca 4 H 4 Si 5 O 16 , Ca 2 H 2 Si 2 O 7 and Ca 6 (HSi 2 O 7 ) 2 (OH) 2 , respectively. The variation of the Ca/Si ratio of the three phases has been described by surface reactions: the increase of the Si content is accounted for by silicate bridging, the increase of calcium content and the surface charge are accounted for by reactions involving silanol groups v…

Shear coefficient determination in linear friction welding of aluminum alloys

2015

In the present study, a combined experimental and numerical investigation on Linear Friction Welding (LFW) of AA2011-T3 aluminum alloy was carried out in order to find the temperature dependent shear coefficient to be used in a 3D numerical model of the process. Torque, oscillation frequency and pressure were acquired in order to calculate the shear stress at the interface. A numerical thermal model was used to calculate the temperature at the interface between the specimens starting from experimental temperatures acquired through a thermocouple embedded in the LFW specimens. Finally, the calculated shear coefficient was used to model the contact between the two specimens in a dedicated 3D,…

Jóvenes migrantes al habla: trayectorias educativas y vidas con género

2018

El artículo muestra la tensión biográfica y el proceso educativo de dos jóvenes menores que viajaron de África a Europa a través de construcciones biográficas marcadas por el paso de sociedad de origen a sociedad de destino. El relato y la representación gráfica de la trayectoria vivida aportan elementos de reflexión sobre el encauzamiento del alumnado de incorporación tardía en nuestra sociedad. Ambas biografías se extraen de una investigación que tiene por objeto conocer qué hace posible la progresión educativa exitosa del alumnado de incorporación tardía que vive en contextos vulnerables. A través de trayectorias encauzadas por el género y una clase social de origen media, Badra y Dakar …

A procedure to calculate the I–V characteristics of thin-film photovoltaic modules using an explicit rational form

2015

Abstract Accurate models of the electrical behaviour of photovoltaic modules are effective tools for system design. One or two diode equivalent circuits have been widely used even though some mathematical difficulties were found dealing with implicit equations. In this paper, a new model based on a simple rational function, which does not contain any implicit exponential form, is presented. The model was conceived in order to be used with thin-film photovoltaic modules, whose current–voltage curves are characterised by very smooth shapes. The parameters of the model are evaluated by means of the derivatives of the issued characteristics in the short circuit and open circuit points at standa…

Restoration of the Zisa Palace, Palermo

1993

The building of the Zisa, commissioned by William I, began in 1164-1165; it was completed by William II in the years immediately following. It was built as a splendid place for rest and amusement, ...

A Paradigm Interpreting the City and the Analytic Network Process for the Management of Urban Transformations

2018

When urban and environmental transformations occur in areas where the equilibrium between nature and culture is complex and fragile, public ad-ministrations could decide to induce private investments using several tools, such as financial contributions to those projects of refurbishment that better re-spect the purpose of improving the environmental quality and of preserving the local architecture. Multicriteria models may support public decision process re-garding this issue, but it is essential to adopt a scientific paradigm that provides a major theoretical reference. This study proposes the development of a net-work model based on the scientific paradigm by Rizzo and the Analytic Net-wo…