Search results for " Structural"
showing 10 items of 1751 documents
Analysis of high-frequency rotational angioplasty-induced echo contrast.
1991
During high-frequency rotational angioplasty (HFRA), myocardial contrast enhancement (echo contrast) was observed by means of two-dimensional echocardiography. In order to evaluate the echo contrast produced by HFRA, an in vitro experimental model was built using a cylinder with the HFRA catheter scanned in a water bath. The cylinder was filled with blood, mineral water, and distilled water. With a 2.5-MHz transducer, echograms were recorded and analyzed by video intensitometer, and the maximum intensity IUmax and persistence time P were calculated. Rotation frequencies of 20,000-200,000 rpm with 2.0--mm burrs and times of 10 s were tested. In another model, hyperbaric conditions for the sa…
Canal transportation caused by a new instrumentation technique and three standard techniques
1996
The ability of three different enlarging techniques (balanced force concept, step-back, and recapitulation) and a prototype system to maintain the original canal path during root canal preparation were compared, in vitro, with a theoretical ideally prepared root canal. Measurements were made at the concave and convex sides of the canal at four different levels (1, 4, 5, and 7 mm from apical, respectively). Simulated root canals embedded in clear casting resin and an enlarging computer-supported device were used for this study. The results showed that none of the enlarging techniques used in this study was able to prepare a canal ideally. The prototype system, at level 1, showed an ideal amo…
Training program for transanal endoscopic microsurgery.
1988
Televised endoscopy and the concept of the “assisted” endoscopic operation is of great help in teaching surgical endoscopic techniques. The use of training dummies provides a new method of training manual dexterity and surgical skills in special courses or in surgical skill laboratories. We have developed a training system for transanal endoscopic microsurgery. Operations with our technique were performed on 116 patients. Like other microsurgical techniques, our method requires a special introduction and intensive training. This paper presents our multistage, video-supported training course for teaching transanal endoscopic microsurgery. The one-day training session is divided into four ste…
The vaccinaTion & Hpv Knowledge (THinK) questionnaire: a reliability and validity study on a sample of women living in Sicily (southern-Italy)
2019
Objective The aim of this study was to introduce the VaccinaTion & Hpv Knowledge (THinK) questionnaire to assess knowledge about human papillomavirus (HPV) and attitude to HPV-vaccination. Its reliability and validity was demonstrated in a sample of women living in Sicily (southern Italy). Methods A cross-sectional survey was conducted on a sample of 220 women at the “Paolo Giaccone” University Hospital in Palermo (Sicily), aged 18–61. Data were analyzed through Cronbach’s alpha and exploratory factor analysis, followed by a structural equation model with measurement component. The two-level data structure was explicitly considered. Results Three dimensions were found: “knowledge of HP…
Validation of the Cycling Behavior Questionnaire: A tool for measuring cyclists' road behaviors
2018
Abstract Introduction Even though cycling is an activity whose benefits in terms of urban mobility and health are globally recognized, its disproportional growth during the past few decades has led to some unexpected dynamics. In fact, the increasing number of traffic injuries and deaths involving cyclists has a high cost for public health systems. Considering the available empirical evidence, aberrant and positive behaviors on the road constitute relevant predictors for the injuries suffered by road users. Nevertheless, the scarcity of tools that measure and evaluate the behavior of road users, especially in the case of cyclists, constitutes a serious lack in terms of explaining, interveni…
A Comparative Study of Mechanical and Microstructural Behavior for Metal Active Gas and Friction Stir Welded Micro-Alloyed Structural Steel
2022
Manufacturing tiny components into gigantic structures seems unimaginable without welding connections, whether it is for materials, parts, structures, or equipment. In the recent competitive market scenario, manufacturing industries are desperately looking for a viable alternative to fusion-based conventional material joining technologies, to improve upon cost-effectiveness along with performance. The present investigation is to evaluate the performance of structural steel thick plate joints prepared by advanced solid-state friction stir welding (FSW) over conventional metal active gas welding (MAG). The FSW experiments were carried out with different tool designs and configurations. The ou…
Decomposition Process of Carboxylate MOF HKUST-1 Unveiled at the Atomic Scale Level
2016
HKUST-1 is a metal-organic framework (MOF) which plays a significant role both in applicative and basic fields of research, thanks to its outstanding properties of adsorption and catalysis but also because it is a reference material for the study of many general properties of MOFs. Its metallic group comprises a pair of Cu2+ ions chelated by four carboxylate bridges, forming a structure known as paddle-wheel unit, which is the heart of the material. However, previous studies have well established that the paddle-wheel is incline to hydrolysis. In fact, the prolonged exposure of the material to moisture promotes the hydrolysis of Cu-O bonds in the paddle-wheels, so breaking the crystalline n…
RC Columns Strengthened with Steel Angles and Battens: Experimental Results and Design Procedure
2013
In this paper, an analytical model for the design of axially loaded strengthened RC columns with steel angles and battens is presented. Cases of directly loaded and not directly loaded steel angles are considered. The model considers the contribution in confinement pressures caused by transverse battens and steel angles and the contribution in terms of the load-carrying capacity of steel angles subjected to axial force and the bending moment. An experimental investigation on the compressive behavior of eight short, confined, RC columns externally strengthened with steel angles and steel battens with various pitches was carried out, and has been utilized as support for the analytical model. …
What makes a champion? : motorcycle world champions' recipe for success
2011
This thesis explores what are the factors that impact the success in motorcycle racing. The subject is relevant to investigate since there have not been many scientific researches of motorcycle sport and the factors behind the success. Fifty-four motorcycle World Champions from 16 different countries and representatives of the six most successful motorcycle sport countries answer to the research question: “What makes a champion in motorcycle sport?” It is also investigated how the society influences the success in motorcycle sport and how the federations and clubs could improve their training programmes. The empirical data was collected by interviewing the experts in the field of elite-leve…
Analysis and optimization of hybrid double lap aluminum-GFRP joints
2014
In this paper a systematic investigation of the mechanical performance of hybrid double-lap Al-GFRP bonded-bolted joints, has been carried out by using experimental analyses and numerical simulations. In order to detect the optimal geometric configuration, as well as to highlight the contribution of adhesive and bolts, the results relative to hybrid joints have been compared with those of simply adhesively bonded and simply bolted joints. The experimental and numerical results have shown that by using the minimum overlap length provided from theory, the bolt leads to a significant decreasing of both the maximum shear and the maximum peel stresses in the adhesive layer and, consequently, the…