556 research outputs found
Compressive and shear behaviour of masonry panels: experimentation and numerical analysis
The compressive and shear behavior of masonry is here studied both experimental- ly and numerically. An experimental campaign has been carried out on 9 square-shaped one leaf masonry panels, reproducing historical masonry. Tests have been done for evaluating the elastic and shear moduli in both plane directions, with 6 panels rotated by 90 degrees, lead- ing to vertically aligned bed joints, and 3 panels maintained with horizontal bed joints. Com- pressive tests were executed on 6 masonry panels, 3 of them rotated by 90 degrees. Initial shear strength and shear modulus parallel to bed joints are evaluated through shear tests on 9 masonry triplets. Shear tests are performed on 3 rotated panels, applying an horizontal dis- tributed load, without vertical compression. Attention is paid to the service load state: only the initial phase of the tests is studied. Numerical models are proposed for representing actu- al masonry behavior, both discrete [1] and continuous [2,3], standard and micropolar, ob- tained by homogenization procedures [4]. Several numerical analyses are performed for simulating the experimental tests on masonry triplets and panels. The mechanical elastic pa- rameters of both discrete and continuous models are calibrated starting from laboratory data of masonry constituents and then by fitting the results of the initial phases of the experimental tests on masonry specimens
Damage-imperfection indicators for the assessment of multi-leaf masonry walls under different conditions
The complexity of multi-leaf masonry walls suggests further researches on the dy- namic behaviour mainly characterized by incoherent response between the different layers. The intrinsic discontinuity and the manufacturing imperfections are amplified by the incre- mental damage that triggers different failure mechanisms that affect the dynamic parameters, such as modal shapes, frequencies and damping ratios. The dynamic identification with out- put only methodology has been proposed in this work on different multi-leaf masonry walls subjected to uniaxial compressive load. The responses of full infill, damaged infill and strengthened infill masonry panels with different widespread damage have been recorded. The evolution of the damage scenario changes the modal shapes, the related frequencies and the damping ratios that through the comparison with the data of the initial conditions can de- tect the anomalies and then the intrinsic vulnerabilities. Through the curvature modal shape methods and the structural irregularity indices applied to different phases, it was possible evaluate the imperfection and the induced damage entity
A finite element-discrete element approach for the analysis of the venice trans-lagoon railway bridge
In this paper, the feasibility of the utilization of a combined finite element/discrete element (FE-DE) approach to investigate the behavior of masonry arch bridges is proposed. Attention is paid to the assessment of the load carrying capacity by means of a suitable coupled FE-DE two-dimensional approach. This paper outlines the fields and limits of applicability of the FE-DE method to the study of masonry arch bridges. The main contribution is to evaluate the applicability of FE-DE, in particular its reliability to describe the nonlinear behavior of masonry arch bridges under increasing static loads, to catch kinematic failure mechanisms and collapse load multipliers, as well as to evaluate the role played by the backfill. A discussion on a possible approach to FE-DE modelling of the Venice trans-Lagoon masonry arch bridge is proposed. With such a purpose, a series of parametric analyses has been conducted in order to evaluate the influence of the different parameters involved on the behavior of the bridges. Pushover analyses have been performed to investigate the nonlinear behavior up to the collapse and up to a clear formation of a failure mechanism in the model
Role of crossmatch testing when Luminex-SAB is negative in renal transplantation
The human leukocyte antigen (HLA) system plays an important role in the acceptance of renal graft. Long and better graft survival has been reported in patients with HLA-identical siblings and a nonreactive cytotoxicity assay (CDC). New methods of HLA-typing and anti-HLA antibody detection techniques such as flow cytometry, solid-phase immunoassays, or antigen bead assays have further improved the outcomes of renal transplant recipients. In the present review, the explicit details of these methodologies are discussed in detail
Follicular thyroid carcinoma: Differences in clinical relevance between minimally invasive and widely invasive tumors
Evidence on the biological behavior and clinical courses of minimally invasive and widely invasive follicular thyroid carcinoma (MI-FTC, WI-FTC) is still debatable. The current study was conducted to identify differences between MI and WI tumors and those prognostic parameters influencing late outcome such as local recurrence and survival
Multidisciplinary approach for a new vision of urban requalification. Multi-scale strategies of social innovation, economic improvement and environmental sustainability practices
Ponència presentada a: Session 7: Participación en planeamiento / Participation in planning. Environmental and hermeneutic plannin
Multidisciplinary approach for a new vision of urban requalification. Multi-scale strategies of social innovation, economic improvement and environmental sustainability practices
Ponència presentada a: Session 7: Participación en planeamiento / Participation in planning. Environmental and hermeneutic plannin
Are Connected Fitness Machines the New Blue Ocean Marketing Strategy for Tourism Marketing (Red Ocean) or the Wellness Industry (Red Ocean)? An Exploration of Connected Signaling
The question is centered around connected (Internet of Things) Fitness Machines which virtually transport the user of the machine to a destination (Spain, Italy, St. Lucia, Fiji, New Zealand to name a few) while the user is engaged in some form of fitness activity (running, walking, rowing, cycling, etc.). The intended idea or primary marketing message is that the user gets a ‘personal’ trainer to aid in their fitness journey while at the same time enjoying the ‘outdoors’ in the comfort of their home. The seemingly unintended consequence is that each ‘outdoor’ location is marketed uninterrupted for 15 to 30 minutes at least. This begs the question – will these connected machines encroach on traditional advertising expenditure for destination marketing? Can connected (internet of things) Fitness machines move two product categories from Red Ocean competitiveness to Blue Ocean Competitiveness? Does the signaling engagement positively affect customer choice/willingness to choose a destination
Case report on the role of radiofrequency-assisted spleen-preserving surgery for splenic metastasis in the era of check-point inhibitors.
RATIONALE: An isolated splenic metastasis is a rare phenomenon noted in advanced stage melanoma. We report the role of radiofrequency (RF) -based splenic-preserving splenectomy in a patient with a solitary splenic metastasis from advanced stage melanoma that was managed with checkpoint inhibitors. PATIENT CONCERNS: We report a case of a 60-year-old man who presented with multiple lung metastases and a solitary splenic metastasis with advanced stage melanoma following excision of primary from his trunk 2.3 years back. DIAGNOSIS: Considering the diagnosis of advanced stage melanoma with multiple lung metastases and a solitary splenic metastasis, and its ongoing progressive nature. This case was discussed in the tumour board meeting. INTERVENTIONS: A decision was made to commence treatment with immunotherapy in the form of PD-1 inhibitor (programmed cell death 1 receptor) pembrolizumab. Follow-up restaging computer tomography (CT) scan of the abdomen and chest showed a significant reduction in the lung and chest wall lesions, but the splenic lesion remained unchanged. Given the lack of response to treatment in the splenic metastasis and the significant decrease in lung metastases, the multidisciplinary team decided that a partial splenectomy combined with continued immunotherapy treatment would be appropriate as the success of immunotherapy was imminent within the splenic preservation. OUTCOMES: The postoperative recovery was smooth and the patient was discharged from hospital on the sixth postoperative day with normal platelets and white blood cells. The histopathological analysis of the resected specimen showed a metastatic melanoma with negative margins.At 10-month follow-up after the splenic resection the patient had not experienced further tumour recurrences. LESSONS: Spleen-preserving resection for an isolated, solitary splenic metastasis of melanoma is a feasible approach as it not only preserves the ongoing efficacy of checkpoint inhibitors by preserving the physiological T cell milieu, but the immunomodulation properties of RF can produce potentially additional therapeutic benefit
A Procedure to Investigate the Collapse Behavior of Masonry Domes: Some Meaningful Cases
Masonry domes represent an important part of the architectural heritage. However, the literature about domes analysis seems less consistent than that referred to other masonry structures. The collapses that have happened in recent years as a consequence of seismic actions or lack of maintenance show the need for detailed studies. Here a limit analysis to evaluate the masonry domes behavior is presented. An algorithm based on the kinematic approach has been developed to evaluate the geometric position of the hinges that determine the minimum collapse load multiplier. The proposed procedure is validated by a comparison with some meaningful cases— the collapse of Anime Sante Church in L’Aquila, the collapse of San Nicolò Cathedral in Noto, the crack pattern of San Carlo Alle Quattro Fontane Church in Rome, and the analysis developed on Hagia Sofia in Istanbul. The comparison with real cases shows a good agreement between the model results and the phenomenological crack patterns
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