53 research outputs found

    Shaking table tests and numerical analyses on a scaled dry-joint arch undergoing windowed sine pulses

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    The damages occurred during recent seismic events have emphasised the vulnerability of vaulted masonry structures, one of the most representative elements of worldwide cultural heritage. Although a certain consensus has been reached regarding the static behaviour of masonry arches, still more efforts are requested to investigate their dynamic behaviour. In this regard, the present paper aims to investigate the performance of a scaled dry-joint arch undergoing windowed sine pulses. A feature tracking based measuring technique was employed to evaluate the displacement of selected points, shading light on the failure mechanisms and gathering data for the calibration of the numerical model. This was built according to a micro-modelling approach of the finite element method, with voussoirs assumed very stiff and friction interface elements. Comparisons with existing literature are also stressed, together with comments about scale effects.This work was partly financed by FEDER funds through the Competitivity Factors Operational Programme-COMPETE and by national funds through FCT-Foundation for Science and Technology within the scope of the Project POCI-01-0145-FEDER-007633.info:eu-repo/semantics/publishedVersio

    Repair of composite-to-masonry bond using flexible matrix

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    The paper presents an experimental investigation on an innovative repair method, in which composite reinforcements, after debonding, are re-bonded to the substrate using a highly deformable polymer. In order to assess the effectiveness of this solution, shear bond tests were carried out on brick and masonry substrates within two Round Robin Test series organized within the RILEM TC 250-CSM: Composites for Sustainable strengthening of Masonry. Five laboratories from Italy, Poland and Portugal were involved. The shear bond performance of the reinforcement systems before and after repair were compared in terms of ultimate loads, load-displacement curves and strain distributions. The results showed that the proposed repair method may provide higher strength and ductility than stiff epoxy resins, making it an effective and cost efficient technique for several perspective structural applications

    No evidence of association between prothrombotic gene polymorphisms and the development of acute myocardial infarction at a young age

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    Background : we investigated the association between 9 polymorphisms of genes encoding hemostasis factors and myocardial infarction in a large sample of young patients chosen because they have less coronary atherosclerosis than older patients, and thus their disease is more likely to be related to a genetic predisposition to a prothrombotic state Methods and Results : this nationwide case-control study involved 1210 patients who had survived a first myocardial infarction at an age of 45 years who underwent coronary arteriography in 125 coronary care units and 1210 healthy subjects matched for age, sex, and geographical origin. None of the 9 polymorphisms of genes encoding proteins involved in coagulation (G-455A -fibrinogen: OR, 1.0; CI, 0.8 to 1.2; G1691A factor V: OR, 1.1; CI, 0.6 to 2.1; G20210A factor II: OR, 1.0; CI, 0.5 to 1.9; and G10976A factor VII: OR, 1.0; CI, 0.8 to 1.3), platelet function (C807T glycoprotein Ia: OR, 1.1; CI, 0.9 to 1.3; and C1565T glycoprotein IIIa: OR, 0.9; CI, 0.8 to 1.2), fibrinolysis (G185T factor XIII: OR, 1.2; CI, 0.9 to 1.6; and 4G/5G plasminogen activator inhibitor type 1: OR, 0.9; CI, 0.7 to 1.2), or homocysteine metabolism (C677T methylenetetrahydrofolate reductase: OR, 0.9; CI, 0.8 to 1.1) were associated with an increased or decreased risk of myocardial infarction Conclusions : this study provides no evidence supporting an association between 9 polymorphisms of genes encoding proteins involved in hemostasis and the occurrence of premature myocardial infarction or protection against it

    Spontaneous cure of a ruptured intracranial aneurysm.

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    A rare case of spontaneous cure of an internal carotid artery aneurysm is reported; the progressive resolution of the spasm and the disappearance of the aneurysm have been confirmed by serial angiograms respectively performed two weeks, two months and four months after the hemorrhage. The other 14 reported cases of angiographically documented spontaneous cure of intracranial aneurysms are reviewed and the possible causes of spontaneous aneurysmal thrombosis, such as retarded cerebral circulation, arterial spasm, size of the neck, thrombosis of the feeding artery and antifibrinolytic therapy, are discussed

    Fronto-ethmoidal and orbital osteomas with intracranial extension. Report of two cases.

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    Osteomas involving the anterior cranial base are quite rare lesions. Intracranial and orbital extension of these tumors, causing neurological and ophthalmological symptoms and signs is a rare event. Two such cases are reported. In the first one, the tumor arose from the frontal sinus and extended upward to the medial and superior wall of the right orbital cavity and the lower part of the right frontal convexity. In the second case the osteoma arose from the left orbital roof and extended to the lower part of the homolateral frontal convexity and the splenoid wing. After the operation the symptoms disappeared and the cosmetic deficits were corrected. Skull-films, CT and MR well define the bony extension and the displacement of the orbital and intracranial structures. Indications to the surgery include progressive ophthalmologic and neurologic signs and significant cosmetic deformations. The surgical techniques and the postoperative complications are briefly discussed
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