Experimental and Numerical Analysis on the Core Lateral Thrust in Bolted BRBs

The paper aims at presenting numerical and experimental results on the lateral thrust exerted by the inner core of a buckling restraining brace (BRB) when, after buckling in compression, it arrives into contact with the external restraining case. The BRB consisted of a plate core restrained by bolted U- shaped member, thus allowing an easy assembly of the BRB, as well as the inspection and the substitution of its core after a seismic event [1, 2]. The results of six tests on BRBs having a plate core with a cross section of 5x50 mm2 and a dissipative length of 560 mm are shown. The gap dimension was varied between 0.25 and 0.70 mm. Cyclic displacements of increasing amplitude were applied to the core up to a steel strain of 2%, adopting the loading history prescribed by AISC standards [3]. The instrumented bolts connecting the restraining elements and a thin tactile pressure sensor placed within the gap allowed to steadily monitor both the lateral thrust and the buckling shape of the plate core during the experiment. The results showed that the lateral thrust increased linearly with the gap dimension, thus confirming the trend provided by the analytical formulation proposed by Genna and Gelfi [4]. As reported in Table 1, for a maximum axial force of about 110 kN, the value of the transverse thrust ranged from 36.5 kN in the specimen 1 with a gap of 0.25 mm to 86.6 kN in the specimen 3 with a gap of 0.70 mm. Furthermore, the specimens 6, without stiffening plates in the web of the restraining U- profiles, showed the significant role of the local transverse deformation on the value of the lateral thrust, which was twice the thrust of the specimen 1, characterized by the same gap of 0.25 mm but with a stiffened case. The experimental results allowed to validate a non-linear 3D Finite Element model performed with the code ABAQUS [5]. The numerical analyses accurately predicted the cyclic behaviour of the tested BRBs in term of axial load, buckling shape of the core and lateral thrust action. The difference between the measured thrust and the calculated thrust at the end of the loading history (steel strain c=2%) ranges between -8% to +17%, while the 2D plane stress model proposed in [6] overestimated the lateral thrust of +85%, owing to the inability of the 2D model to describe the local transverse deformations of the case

Statistical Approach to Fiber Laser Microcutting of NIMONIC® C263 Superalloy Sheet Used in Effusion Cooling System of Aero Engines

AbstractIn order to reduce thermal stress and avoid premature failure of turbine blades in the hot section of aero-engines, a diffusion cooling system is often adopted. This system is a thin sheet, with a closely spaced holes array allowing a uniform cooling of the turbine blade thanks to the evenly distributing of the cooling fluid within its wall. The holes diameters vary in the range of 0.3-1.0 mm. Furthermore, tight tolerances, perpendicular surfaces, no burr, no recast layer, are required. In order to satisfy the hole requirements, typically EDM technique is adopted. However, EDM micro-drilling needs long process time (about 20 s for hole). A promising alternative is laser trepanning. In this technique, a laser beam, with a very small focused spot, is used to make a hole by circular cutting. The hole is obtained in few seconds (<3 s). In this work a preliminary study on laser microcutting of NIMONIC® C263 sheet is presented in order to verify the possibility to adopt a low-power Yb:YAG fiber laser for the microdrilling. Linear cutting tests were carried out on NIMONIC® C263 superalloy sheet, 0.38 mm thick, using a 100 W Yb:YAG fiber laser working in modulated regime. A systematic approach based on Design of Experiment (DoE) has been successfully adopted with the aim to detect which and how the process parameters affect the kerf geometry in term of kerf width, taper angle and tolerances. The examined process parameters were scan speed, on-time, pulse duration and gas pressure. A full factorial design and ANalysis Of VAriance (ANOVA) were applied. Experimental results show the possibility to obtain kerf characterized by narrow width (<100 μm), low taper angle values (<1.8°) and small tolerance (<0.22 μm). Then, the possibility to produce in-tolerance holes was proved

Understanding historical events through dress and costume displays in Titanic museum attractions

The sinking of the RMS Titanic has achieved a difficult feat – it has remained culturally relevant. The dedication of the general public to understanding Titanic is evident in many avenues of popular and consumer culture. For those individuals who did not get enough of the 1997 Titanic movie, there are numerous Titanic museums and attractions to visit. What interests me as a scholar of historic dress is that the 1997 film is often used as a lens through which the historical events are interpreted and understood. More specifically the character of Rose (from the 1997 Titanic movie) has been translated from a film character to a living history character. Rose has become an integral part of the marketing and exhibiting techniques at some Titanic museum attractions. The purpose of this research was to conduct an introductory exploration of the role of film costume iconography in learning about a historical event and the development of a personal connection with an iconic character in the context of that event. Four permanent Titanic museum attractions were selected as sites of study: museum attractions in Branson, Missouri; Pigeon Forge, Tennessee; Orlando, Florida; and Las Vegas, Nevada. A total of 32 participants were included. Both museum attraction visitors and staff participated in this study; twenty-nine participants were classified as visitors and three participants were classified as staff. Phenomenological and inductive approaches were undertaken. Qualitative (personal phenomenology, phenomenological interviews, and brief participant observation) data collection techniques were employed. Both descriptive and experiential phenomenological and narrative approaches were combined to analyze the resulting data. I utilized a descriptive phenomenological method outlined by Giorgi and Giorgi (2003), and I made modifications to the procedure to fit the unique needs of my data. Data collection occurred in two phases at each location. In phase one, I participated in personal phenomenology during a visit to each museum attraction. In phase two, I collected data with participants. Data collection with visitor participants occurred in three stages: (1) pre-museum attraction visit interview, (2) the participant visited a Titanic museum attraction, and (3) post-museum attraction visit interview. I collected data with each staff participant during one interview. The findings of this study revealed that there are many perspectives from which to tell the story of Titanic and help museum attraction visitors learn the history of the ill-fated ship. I found that Rose did not factor into the decision of the participants to visit a Titanic museum attraction. If a participant learned from or about Rose, she did not factor into the learning or personal meaning-making process until he or she was inside the museum attraction. It was more common for participants to relate to the historical events of Titanic through the movie as a whole, as opposed to the specific character of Rose. The scenario of including a Rose living history interpreter as part of the lived experience of a museum visit elicited a wide range of reactions from participants. It was more common for participants to oppose the presence of a Rose living history interpreter than favor her presence. Several participants reported instances when they drew a spontaneous connection to the movie or were reminded of the movie in their own mind. Several participants used the movie as a foundation to build further historical understanding about Titanic. Some participants used the movie as a source of comparison to explore or confirm the accuracy of the movie. The primary difference in the museum attraction experience for visitors who had not seen the movie was that they encountered difficulty in relating and paying attention to any content or reference to the movie. A general phenomenological structure was formed from the data. As part of this study, I sought to further expand the body of literature that applies visual rhetorical theory and semiotic theory to dress and costume. A discussion of the resulting theoretical implications is included. An outcome of the phenomenological data collection and analysis was a list of recommendations for future practice specifically related to the display of dress and costume in both Titanic museum attractions and museums in general. I conclude with recommendations for future research and a reflective summary

Vino e Ambiente: sostenibilità e qualità primaria nel sottobacino Iudeo-Bucari (TP).

In questa raccolta di scritti, vengono riportati i risultati dell’attività di ricerca realizzata con la collaborazione della cantina UVAM e dell’Istituto Regionale Vino e Olio di Sicili

Laser Marking of Titanium Coating for Aerospace Applications

Abstract In the aerospace industry, in order to ensure the identification and the traceability of the products, high repeatability, non-invasive and durable marking processes are required. Laser marking is one of the most advanced marking technologies. Compared to traditional marking processes, like punches, microdot, scribing or electric discharge pencil etcher, laser marking offers several advantages, such us: non-contact working, high repeatability, high scanning speed, mark width comparable to the laser spot dimension, high flexibility and high automation of the process itself. In order to assure the mark visibility for the component lifetime, an appropriate depth of the mark is required. In this way, a stable behaviour is ensured also when the component operates in aggressive environments (i.e. in presence of oxidation, corrosion and wear phenomena). The mark depth is strongly affected by the laser source kind and by the process parameters, such us average power, pulse frequency and scanning speed. Moreover, an excessive mark penetration could cause stress concentrations and reduce the fatigue life of the component. Consequently, an appropriate selection of the process parameters is required in order to assure visibility and to avoid excessive damage. Cold Spray Deposition (CSD) is a relative new technology that allows to produce surface coatings without significant substrate temperature increasing. In aeronautics fields this technology is useful to coat materials sensible to temperature, such as solution tempered aluminum alloy, with a titanium layer. Aim of the work is to characterize the laser marking process on CSD Ti coating, in order to study the influence of the laser marking process parameters (pulse power and scanning speed), on the groove geometry of the marking. The experimental marking tests were carried out through a 30 W MOPA Q-Switched Yb:YAG fibre laser; under different process conditions. The groove geometry was measured through a HIROX HK9700 optical microscope. The results showed the effectiveness of the laser process to produce high quality marks on the titanium layer. Moreover, a correlation between the process parameters and the mark's geometry was clearly observed

A Smartphone Application Designed to Engage the Elderly in Home-Based Rehabilitation

As life expectancy increases, it is imperative that the elderly take advantage of the benefits of technology to remain active and independent. Mobile health applications are widely used nowadays as they promote a healthy lifestyle and self-management of diseases, opening new horizons in the interactive health service delivery. However, adapting these applications to the needs and requirements of the elderly is still a challenge. This article presents a smartphone application that is part of a multifactorial intervention to support older people with balance disorders. The application aims to enable users to self-evaluate their activity and progress, to communicate with each other and, through strategically selected motivational features, to engage with the system with undiminished interest for a long period of time. Mock-up interfaces were evaluated in semi-structured focus groups and interviews that were performed across three European countries. Further evaluation in the form of four pilot studies with 160 participants will be performed and qualitative and quantitative measures will be used to process the feedback about the use of the application

Coherence and Consciousness: Study of Fronto-Parietal Gamma Synchrony in Patients with Disorders of Consciousness

Evaluation of consciousness needs to be supported by the evidence of brain activation during external stimulation in patients with unresponsive wakefulness syndrome (UWS). Assessment of patients should include techniques that do not depend on overt motor responses and allow an objective investigation of the spontaneous patterns of brain activity. In particular, electroencephalography (EEG) coherence allows to easily measure functional relationships between pairs of neocortical regions and seems to be closely correlated with cognitive or behavioral measures. Here, we show the contribution of higher order associative cortices of patients with disorder of consciousness (N\ua0=\ua026) in response to simple sensory stimuli, such as visual, auditory and noxious stimulation. In all stimulus modalities an increase of short-range parietal and long-range fronto-parietal coherences in gamma frequencies were seen in the controls and minimally conscious patients. By contrast, UWS patients showed no significant modifications in the EEG patterns after stimulation. Our results suggest that UWS patients can not activate associative cortical networks, suggesting a lack of information integration. In fact, fronto-parietal circuits result to be connectively disrupted, conversely to patients that exhibit some form of consciousness. In the light of this, EEG coherence can be considered a powerful tool to quantify the involvement of cognitive processing giving information about the integrity of fronto-parietal network. This measure can represent a new neurophysiological marker of unconsciousness and help in determining an accurate diagnosis and rehabilitative intervention in each patient

Le prove di vinificazione della cultivar grillo su tre vigneti sperimentali site nel sottobacino Iudeo - Bucari (TP).

Gli Autori, dopo aver descrittole caratteristiche ambientali del sottobacino Iudeo Bucari e l’attività agricola prevalentemente legataalla vitivinicoltura, descrivono alcune prove di vinificazione di uve Grillo provenienti da tre vignesite nel sottobacino Iudeo – Bucari gestite in modo ordinario, delle quali si è monitorata la maturazione delle uve. L'obiettivo è quello di caratterizzare il prodotto vino ottenuto attraverso una tecnica di vinificazione uniforme ed ordinaria nella zona, ma che mira a mettere in evidenza la diversa qualità tecnologica delle uve utilizzate espressione dicontesti eco-pedologici diversi

A porous fibrous hyperelastic damage model for human periodontal ligament: Application of a microcomputerized tomography finite element model

The periodontal ligament (PDL) is a soft biological tissue that connects the tooth with the trabecular bone of the mandible. It plays a key role in load transmission and is primarily responsible for bone resorption and most common periodontal diseases. Although several numerical studies have analysed the biomechanical response of the PDL, most did not consider its porous fibrous structure, and only a few analysed damage to the PDL. This study presents an innovative numerical formulation of a porous fibrous hyperelastic damage material model for the PDL. The model considers two separate softening phenomena: fibre alignment during loading and fibre rupture. The parameters for the material model characterization were fitted using experimental data from the literature. Furthermore, the experimental tests used for characterization were computationally modelled to verify the material parameters. A finite element model of a portion of a human mandible, obtained by microcomputerized tomography, was developed, and the proposed constitutive model was implemented for the PDL. Our results confirm that damage to the PDL may occur mainly because of overpressure of the interstitial fluid, while large forces must be applied to damage the PDL fibrous network. Moreover, this study clarifies some aspects of the relationship between PDL damage and the bone remodelling process