Rocking of freestanding objects: theoretical and experimental comparisons

The methodical study of safeguard of artistic heritage and other devices subjected to earthquake and, in general, to time-dependent forces has considerably spreaded in the last years, thus increasing researchers' interest in problems concerning motions of rigid objects simply supported on a base plane. The behaviour of piece of equipments, statues, storage tanks, or even tall buildings has been in fact studied as that of rigid bodies with relation to different base excitations. In some cases, the possibility of influencing the quality of motion can be a strong tool to reduce vulnerability, like in the cases in which rocking motion is to be avoided and sliding motion is welcome. This paper focuses the attention on this last problem. This is the same large class of both non-structural and structural elements that can lose their functionality because of earthquake motions. The results of numerical modelling of sliding and rocking motion in presence of both different excitations and mechanical parameters are presented and compared with experimental data performed by the authors. The results developed are in good agreement with the laboratory tests, and this assures the reliability of both the analytical procedure and the determination of the parameters involved

An exponential matrix method for the buckling analysis of underground pipelines subjected to landslide loads

Abstract Due to their dimensions, long pipelines often cross areas that are highly susceptible to landslides. In Italy, this problem requires special attention, as many slow-moving landslides interact with buried pipelines. The paper analyzes such interaction problem with particular reference to buckling analysis, tackling the solution of the governing equations by an exponential matrix method. In the paper the basic equation, its computational aspects and numerical analysis options are outlined. Representative results of the proposed methodology and potential applications on buckling analysis of buried pipes are presented

Semianalytical Lower-Bound Limit Analysis of Domes and Vaults

The calculation of the collapse load of spherical domes is addressed using a semianalytical approach under the hypothesis of small displacements and perfect plasticity. The procedure is based on the numerical approximation of the self-stress that represents the projection of the balance equilibrium null space on a finite dimensional manifold. The so-obtained self-equilibrated stress span is superimposed onto a finite-element linear elastic solution to the prescribed loads yielding to the statically admissible set accordingly to Melan’s theorem. The compatibility of the stress with the constitutive law of the material was enforced using a linearized limit domain in terms of generalized stress, namely, axial force and bending moment along the local spherical curvilinear coordinates. The procedure was tested with reference to numerical and experimental data from the literature, confirming the accuracy of the proposed method. A comparison with the literature confirms that the buckling load was much greater than the two plastic collapse loads calculated through the proposed procedure and reported in the quoted literature

Experimental and Numerical Evaluation of Residual Displacement and Ductility in Ratcheting and Shakedown of an Aluminium Beam

Safety assessment of structures can be obtained employing limit design to overcome uncertainties concerning actual response due to inelastic constitutive behavior and more generally to non-linear structural response and loads' random variability. The limit analysis is used for evaluating the safety of the structures, starting directly from load level without any knowledge of the load history. In the paper, the lower bound calculation is proposed where a new strain-based approach is used that allowed describing the residual stress and displacement in terms of permanent strain. The strategy uses the permanent strain as effective parameters of the procedure so that it is possible to assess the ductility requirements for the complete load program developed till collapse or shakedown. The procedure is compared to experimental results obtained on aluminum beams in shakedown

Experimental and Numerical Evaluation of Residual Displacement and Ductility in Ratcheting and Shakedown of an Aluminum Beam

Safety assessment of structures can be obtained employing limit design to overcome uncertainties concerning actual response due to inelastic constitutive behavior and more generally to non-linear structural response and loads’ random variability. The limit analysis is used for evaluating the safety of the structures, starting directly from load level without any knowledge of the load history. In the paper, the lower bound calculation is proposed where a new strain-based approach is used that allowed describing the residual stress and displacement in terms of permanent strain. The strategy uses the permanent strain as effective parameters of the procedure so that it is possible to assess the ductility requirements for the complete load program developed till collapse or shakedown. The procedure is compared to experimental results obtained on aluminum beams in shakedown

Managing of Migraine in the Workplaces: Knowledge, Attitudes and Practices of Italian Occupational Physicians

Background and Objectives: Migraine is a debilitating disorder, whose incidence peak in the age group of 30-39 years overlaps with the peak of employment years, potentially representing a significant issue for occupational physicians (OP). The present study was performed in order to characterize their knowledge, attitudes and practices on migraine in the workplaces. Materials and Methods: A convenience sample of 242 Italian OP (mean age 47.8 +/- 8.8 years, males 67.4%) participated in an internet-based survey by completing a structured questionnaire. Results: Adequate general knowledge of migraine was found in the majority of participants. Migraine was identified as a common and severe disorder by the majority of respondents (54.0% and 60.0%). Overall, 61.2% of participants acknowledged migraine as difficult to manage in the workplace, a status that made it more likely for OP understanding its potential frequency (Odds Ratio [OR] 3.672, 95% confidence interval [95%CI] 1.526-8.831), or reported previous managing of complicated cases requiring conditional fitness to work judgement (OR 4.761, 95%CI 1.781-2.726). Moreover, professionals with a qualification in occupational medicine (OR 20.326, 95%CI 2.642-156.358), acknowledging the difficult managing of migraine in the workplaces (OR 2.715, 95%CI 1.034-7.128) and having received any request of medical surveillance for migraine (OR 22.878, 95%CI 4.816-108.683), were more likely to recommend specific requirements for migraineur workers. Conclusions: Migraine was recognized as a common disorder, but also as a challenging clinical problem for OP. Participating OP exhibited a substantial understanding of migraine and its triggers, but residual false beliefs and common misunderstanding may impair the proper management of this disorder, requiring improved and specifically targeted interventions

Experimental investigation on beach morphodynamical process near river mouth

Physical model study on wave influences on river-mouth depositional process is presented. Experiments were performed in a wave basin in order to determine erosion and accretion area due to the combined wave - current flows. An inflow glass channel was designed to reproduce a river mouth model in a 3D wave basin made with a sand bottom. The tests were carried out under three different conditions: River current, waves, wave -current interaction. Measurements of wave heights, beach profiles and bathymetric profiles were made. The results show that in the presence of combined wave-current flows, erosion areas are more evident in vicinity of a mouth with depth and width values greater than depth and width values of inflow channel

Impact of Preventive Strategies on HPV-Related Diseases: Ten-Year Data from the Italian Hospital Admission Registry

Simple Summary HPV-related diseases are mainly represented by cancers. Furthermore, real world data with respect to the effects of primary and secondary preventive strategies are lacking. Therefore, the aim of this study is to assess the effectiveness of preventive strategies in accordance with Italian HPV-related hospital admissions. From 2008 to 2018, there was a decrease (APC = -3.8%) in all HPV-related diseases. The increase in cervical cancer screening adherence was related to a decrease in invasive cervical cancer and an increase in HPV vaccine coverage, which was found to arise from a decrease in "in situ" cervical cancer. In this study, the need to improve the acceptance of preventive strategies for HPV-related diseases, as well as the homogenous information furnished by all healthcare workers involved in their promotion (e.g., gynecologists, general practitioners, pediatricians) is highlighted. Human papillomavirus (HPV)-related diseases are still a challenge for public health. Some studies have shown the effects of preventive strategies on them, but studies at the national level are few in number. Therefore, a descriptive study through hospital discharge records (HDRs) was conducted in Italy between 2008 and 2018. Overall, 670,367 hospitalizations due to HPV-related diseases occurred among Italian subjects. In addition, a significant decrease in hospitalization rates for cervical cancer (average annual percentage change (AAPC) = -3.8%, 95% CI = -4.2, -3.5); vulval and vaginal cancer (AAPC = -1.4%, 95% CI = -2.2, -0.6); oropharyngeal cancer; and genital warts (AAPC = -4.0%, 95% CI = -4.5, -3.5) was observed during the study period. Furthermore, strong inverse correlations were found between screening adherence and invasive cervical cancer (r = -0.9, p < 0.001), as well as between HPV vaccination coverage and in situ cervical cancer (r = -0.8, p = 0.005). These results indicate the positive impact of HPV vaccination coverage and cervical cancer screening on hospitalizations due to cervical cancer. Indeed, HPV vaccination also resulted in a positive impact on the decrease in hospitalization rates due to other HPV-related diseases

Stacking sequences in composite laminates through design optimization

AbstractComposites are experiencing a new era. The spatial resolution at which is to date possible to build up complex architectured microstructures through additive manufacturing-based and sintering of powder metals 3D printing techniques, as well as the recent improvements in both filament winding and automated fiber deposition processes, are opening new unforeseeable scenarios for applying optimization strategies to the design of high-performance structures and metamaterials that could previously be only theoretically conceived. Motivated by these new possibilities, the present work, by combining computational methods, analytical approaches and experimental analysis, shows how finite element Design Optimization algorithms can be ad hoc rewritten by identifying as design variables the orientation of the reinforcing fibers in each ply of a layered structure for redesigning fiber-reinforced composites exhibiting at the same time high stiffness and toughening, two features generally in competition each other. To highlight the flexibility and the effectiveness of the proposed strategy, after a brief recalling of the essential theoretical remarks and the implemented procedure, selected example applications are finally illustrated on laminated plates under different boundary conditions, cylindrical layered shells with varying curvature subjected to point loads and composite tubes made of carbon fiber-reinforced polymers, recently employed as structural components in advanced aerospace engineering applications

Could a Behavioral Model Explain Adherence to Second-Level Colonoscopy for Colon Cancer Screening? Results of a Cross-Sectional Study of the Palermo Province Population

: According to Italian Essential Levels of Assistance (ELA), a colonoscopy is strongly recommended after a positive fecal occult blood test (FOBT) due to its effectiveness in early colorectal cancer detection. Despite the evidence, the Palermo province population (Italy), after a positive FOBT, have a lower colonoscopy adherence compared to Italian standards. This cross-sectional study analyzed patients' perceptions of colonoscopy procedures to understand the reasons for non-adherence. Patients with a positive FOBT who did not undergo a colonoscopy within the national organized screening program were administered a telephone interview based on the Health Belief Model (HBM) questionnaire. The number of non-compliant patients with a colonoscopy after a positive FOBT were 182, of which 45 (25.7%) patients had undergone a colonoscopy in another healthcare setting. Among the HBM items, in a multivariate analysis only perceived benefits were significantly associated with colonoscopy adherence (aOR = 6.7, p = 0.03). Health promotion interventions should focus on the importance of the benefits of colorectal screening adherence to prevent colorectal cancer, implementing health communication by healthcare workers that have closer contacts with people, as general practitioners