Characterisation of Fibre Glass Panels for Naval Use

This work examines the characteristic of fiber glass composite panels constructed by Cantieri Arturo Stabile in Trapani (Italy): composite materials are very used in the naval applications, where high stiffness and resistance are required with reduced weight. Experimental tests are executed following ASTM or UNI EN rules, in particular the shear test is executed using a rig constructed to the purpose, designed following the rule ASTM D 4255-83. Besides the tests were simulated by analytical methods, by means of Cadec software and numerically by FEM software as Altair Hyperworks and Ansys, to evidence the error range of the experimental test and to obtain the configuration that can give suitable results also for more complex designs. The successive phase of optimization is useful to obtain a reduction of the thickness, without compromising the resistance, for a consequent reduction of the production cost and energy saving of the boat during its use

CFD Study of an Innovative Catamaran with Asymmetrical Hulls

The purpose of this paper is the study of the shape of catamaran with asymmetrical hulls by both experimental and numerical viewpoint. The experimental study is based on the towing tank tests on a catamaran hulls shape obtained from previous works, showing that the wave resistance is very low produces a lower energy loss and a greater effectiveness. The hulls shape is optimized by the CFD application by force of commercial software, which shows that the reduction of wasted energy is very sensitive to make some changes; in particular three different width of the catamaran are tested and their performances are compared

Design and use of a Fatigue Test Machine in Plane Bending for Composite Specimens and Bonded Joints

Polymeric and composites materials are increasingly used in industry as structural parts, so that specific information on their mechanical properties "at long term" (creep, relaxation, fatigue) are requested. The design and implementation of these components also requires that they are permanently connected together to perform certain functions. The use of adhesives in structural joints has increased over recent years thanks to the continuous development by companies which provide the market with adhesive having better and better mechanical properties. The main areas relate to the aerospace, aeronautical and automotive industries, where requirements are required for lightness and reliability. One of the main causes of out of order of the glue joints is due to the propagation of defects within the adhesive layer. Indeed, a microscopic defect could evolve because of fatigue loading and then propagate to the final break of the component. The defect may occur during the manufacturing process of the component, during the installation or for the incompatibility of the elements to connect. Delamination depends mainly on the extent of crack and on the mode of loading. Proper design and verification of structural elements cannot therefore leave apart from these aspects, so that in recent decades, in parallel with traditional methods, criteria based on fracture mechanics have been developed for the understanding of issues relating to the damage phenomena. Fatigue tests usually require several hours of application of cyclic stress to obtain an appreciable damage. These tests lead to results more or less uneven as to require the repetition of the test several times to obtain more accurate estimation of the endurance limit. All these considerations are economically incompatible with the use of particularly costly servo-hydraulic machines. Thus the development of a specific approach to fatigue tests based on the use of specific materials testing machines (FTM - Fatigue Testing Machine) becomes very important. Some ideal characteristics of such machines is described in the following: 1) adaptability to different geometries and rigidities of the specimens; 2) ease to perform various conditions of stress (alternate or pulsatory load); 3) possibility to develop studies of fatigue by the recording of the data obtained from different samples of different materials tested, to which any criterion for predicting the fatigue life can be applied; 4) ability to run tests by controlling the amount of deformation; 5) low cost of instrumentation to perform several tests simultaneously; 6) adaptability of the frequency of loading. The purpose of this chapter is to present a material testing machine for fatigue bending stress level that meets all the requirements listed above and to show the results of damage tests of composite material specimens and of the delaminations propagation in bonded joints

Risk of internet addiction in adolescents: A confrontation between traditional teaching and online teaching

Background: The technological evolution has given the opportunities to develop new models of education, like online teaching. However, Internet Problematic Use and Internet Addiction are becoming frequently represented among adolescents with a prevalence that varies worldwide from 2% to 20% of the high school population. Objective: The aim of this study was to analyse the risk of Internet Addiction in a High Schools student sample comparing two different types of schools (online and traditional teaching) and analyzing the associations between pathological use of Internet and socio-demographic factors connected to the different educational orientations and to the daily usage of Internet. Methods: Students were enrolled from four different orientation school programs (different high school, technical and economical Institute, vocational schools). Each student completed a self-reported test to collect socio-demographic data and th Internet Addiction Test (IAT) from K. Young to assess the risk of Internet Addiction. The Mann-Whitney test for quantitative variables was used for statistical analysis. Results: 522 students were enrolled, 243 students from online teaching and 279 from traditional teaching schools. Internet Addiction was observed in 1,16% of the total sample, while 53.83% of subjects was at risk of development Internet Addiction. No significant difference was found between the two different types of teaching, nor considering gender. Considering the amount of time spent on the web in portion of the sample at risk of developing Internet Addiction, the Traditional Teaching group spent between 4 and 7 hours a day on the Web, while the Online Teaching group between 1 to 3 hours/daily. However, no statistically significant difference was found. Conclusion: Although our data demonstrate that there is no clear association between online education and problematic use of Internet, the excessive use of Internet is linked to a massive waste of personal energy in terms of time and social life

Error by design: Methods for predicting device usability

This paper introduces the idea of predicting ‘designer error’ by evaluating devices using Human Error Identification (HEI) techniques. This is demonstrated using Systematic Human Error Reduction and Prediction Approach (SHERPA) and Task Analysis For Error Identification (TAFEI) to evaluate a vending machine. Appraisal criteria which rely upon user opinion, face validity and utilisation are questioned. Instead a quantitative approach, based upon signal detection theory, is recommended. The performance of people using SHERPA and TAFEI are compared with heuristic judgement and each other. The results of these studies show that both SHERPA and TAFEI are better at predicting errors than the heuristic technique. The performance of SHERPA and TAFEI are comparable, giving some confidence in the use of these approaches. It is suggested that using HEI techniques as part of the design and evaluation process could help to make devices easier to use

Smartphone and social network addiction in early adolescents: The role of self-regulatory self-efficacy in a pilot school-based intervention

Background: Youths' online problematic behaviors, such as smartphone or social network sites (SNS) addiction, gained increasing attention nowadays, due to their impact on concurrent and later adjustment, such as emotional and/or behavioral problems, academic impairments, or relational issues. Aims: This study aims to evaluate the effectiveness of a pilot school-based intervention to contrast online addictive behaviors while fostering adolescents' self-regulative abilities. Materials & Methods: The intervention started in January 2022 in an Italian junior high school located in Rome, and consisted of four meetings with students. A total sample of 462 15-year-old adolescents (Mage = 15.2; SD = 0.50; 41% females; Ncontrol = 214; Nintervention = 248) was considered. Within the latent difference score framework, we examined short-term changes from the pre-to-the-postintervention levels of SNS and smartphone addiction, and self-regulatory self-efficacy (SRSE) beliefs as a possible booster of the intervention's effectiveness. Results: Results showed a significant decrease in both online addictions (SNS and smartphone addiction), controlling for age, gender, sexual orientation, and socioeconomic status, because of the short-term efficacy of the project. The buffering effect of SRSE beliefs was further supported. Conclusion: These findings emphasized the usefulness of promoting youths' self-regulative beliefs to contrast problematic tendencies, according to a Positive Youth Development perspective which focused on resources rather than only on the prevention of negative outcomes for youths' adjustment

A Phase II Trial of Fixed-Dose Rate Gemcitabine plus Capecitabine in Metastatic/Advanced Biliary Tract Cancer Patients

Background: This phase II trial was conducted to determine the activity and safety of the combination of fixed-dose rate (FDR) gemcitabine and capecitabine in metastatic biliary tract cancer (BTC) patients. Methods: Patients with unresectable BTC who had pathologically confirmed adenocarcinoma, no prior chemotherapy, Eastern Cooperative Oncology Group (ECOG) performance status 641 and measurable disease were enrolled. Treatment consisted of FDR gemcitabine at 800 mg/m 2 on days 1 and 8 every 21 days with capecitabine administered orally b.i.d. in equal doses (650 mg/m 2 b.i.d.) for 14 days (28 doses). Results: Between May 2005 and February 2009, 30 patients were enrolled. The median age was 67 years (45-76) and there were 14 males. Thirty patients were evaluable for response and toxicity. A total of 221 cycles were administered (median 7, range 2-16). One patient achieved complete response and 7 patients achieved partial response, giving an overall response rate of 26.7% in the intention-to-treat population. Twelve patients (40.0%) had stable disease. The median progression-free survival was 6.33 months. The median overall survival was 10.8 months. Grade 3/4 neutropenia and thrombocytopenia were noted in 13 and 7% of the patients, respectively. Grade 2/3 nonhematologic toxicities were asthenia (54% of patients), diarrhea (17%), stomatitis (23%) and hand-foot syndrome (7%). There was no treatment-related death. The drugs taken were skipped at least once in 45% of the patients and the dose was reduced in 26% of them. Conclusions: The combination of FDR gemcitabine and capecitabine in this 3-week cycle is safe and seems to have a good activity in advanced biliary cancer

Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30