Search results for " mac"

Experimental determination of mode I fracture parameters in orthotropic materials by means of Digital Image Correlation

2020

Abstract The mode I fracture parameters for an orthotropic body are directly calculated from full-field deformation measurements provided by Digital Image Correlation (DIC). Three complementary and direct approaches are evaluated and compared: (i) the determination of the Stress Intensity Factor (SIF) by fitting the displacement field using the analytical expression proposed by Lekhnitskii; (ii) the determination of the J-Integral by using the Energy Domain Integral (EDI) formulation on the raw DIC data; and (iii) the calculation of the J-Integral using the EDI approach on the displacement data fitted using Lekhnitskii’s formulation. A comparative experimental study is performed by testing …

A COMPARISON BETWEEN COMBUSTION PHASE INDICATORS FOR OPTIMAL SPARK TIMING

2008

The closed-loop control of internal combustion engine spark timing may be accomplished by means of a combustion phase indicator, i.e., a parameter, derived from in-cylinder pressure analysis, whose variation is mainly referable to combustion phase shift and assumes a fixed reference value under optimal spark timing operation. The aim of the present work is a comparison between different combustion phase indicators, focusing on the performance attainable by a feedback spark timing control, which uses the indicator as pilot variable. An extensive experimental investigation has been carried out, verifying the relationship between indicators’ optimal values and the main engine running parameter…

Bandgap lowering in mixed alloys of Cs2Ag(SbxBi1−x)Br6 double perovskite thin films

2020

Halide double perovskites have gained significant attention, owing to their composition of low-toxicity elements, stability in air and long charge-carrier lifetimes. However, most double perovskites, including Cs2AgBiBr6, have wide bandgaps, which limit photo conversion efficiencies. The bandgap can be reduced through hallowing with Sb3+, but Sb-rich alloys are difficult to synthesise due to the high formation energy of Cs2AgSbBr6, which itself has a wide bandgap. We develop a solution-based route to synthesis phase-pure Cs2Ag(SbxBi1-x)Br6 thin films, with the mixing parameter x continuous varying over the entire composition range. We reveal that the mixed alloys (x between 0.5 and 0.9) dem…

Effects of mechanical deformation on electronic transport through multiwall carbon nanotubes

2017

Abstract The effects of mechanical deformation on the electron transport behavior of carbon nanotubes (CNTs) are of primary interest due to the enormous potential of nanotubes in making electronic devices and nanoelectromechanical systems (NEMS). Moreover it could help to evaluate the presence of defects or to assess the type of CNTs that were produced. Conventional atomistic simulations have a high computational expense that limits the size of the CNTs that can be studied with this technique and a direct analysis of CNTs of the dimension used in nano-electronic devices seems prohibitive at the present. Here a novel approach was designed to realize orders-of-magnitude savings in computation…

Flying Laser Spot Thermography technique for the NDE of Fibre Metal Laminates disbonds

2017

Abstract The present work investigates the features of an active Infrared-NDT Thermography technique derived from a Flying Laser Spot set-up for the analysis of interlaminar disbonds in layered structures in general and Fibre Metal Laminates in particular. The presented technique uses a laser-spot heat source, which moves at a constant speed, raster scanning the object surface. Interlaminar defects parallel to the surfaces act as barriers towards through-the-thickness heat diffusion. This produces some modifications over the surface thermal field which are well identified in the Standard Deviation calculated over a Reference Area following the heat source. The mechanisms leading to such def…

HERO vs. Zombie: Identifying Zombie Guests in a Virtual Machine Environment

2021

A mobile agent tool for resource discovery

2004

Publisher Summary This chapter discusses a mobile agent based tool for arranging communities whose members want to share computing resources. Such a tool enables community members to arrange their own parallel virtual machine, using resources available within the community. Mobile agents are used to search among available addresses inside the community, and are instructed to select the ones which correspond to the users' requirements. The agent is the key component of the system, because it takes care of the server availability test and of the decision on whether to include them into the virtual machine, according to the user's requirements. The database acts as an intermediary between the …

The Web Computer and Its Operating System: A New Approach for Creating Web Applications

2019

Web applications require not only more sophisticated infrastructure than traditional single-PC applications, but also a different way of thinking, where network-specific aspects have to be considered. In this paper, we introduce the web computer concept, which factors out network-related issues and provides an illusion of a single computer with directly attached CPUs, memory, and I/O devices. By assuming the web computer and its open operating system (webAppOS) as a target platform for web applications, developers can preserve the same level of thinking as when developing classical desktop applications. With this approach, which corresponds to the physiology of the human brain, web applicat…

Writer identification for historical handwritten documents using a single feature extraction method

2020

International audience; With the growth of artificial intelligence techniques the problem of writer identification from historical documents has gained increased interest. It consists on knowing the identity of writers of these documents. This paper introduces our baseline system for writer identification, tested on a large dataset of latin historical manuscripts used in the ICDAR 2019 competition. The proposed system yielded the best results using Scale Invariant Feature Transform (SIFT) as a single feature extraction method, without any preprocessing stage. The system was compared against four teams who participated in the competition with different feature extraction methods: SRS-LBP, SI…

Evaluation of shear bond strength of zirconia to composite resin using different adhesive systems

2019

Background To evaluate shear bond strength of zirconia to composite resin using different universal and conventional adhesives and a zirconia primer. Material and methods Forty zirconia blocks were fabricated of zirconium ingots (10×10×5 mm) and sintered at 1530°C for 2 hours. They were then air-abraded with Al2O3 particles. The specimens were divided into 4 groups and subjected to one of the following bonding agents: Futurabond U (group 1), Clearfil Universal Bond, universal adhesives (group 2), Z-Prime Plus, zirconia primer (group 3) and Adper Single Bond 2, conventional adhesive (group 4). Composite resin was then applied in a diameter of 5 mm and in a thickness of 2 mm. All the specimen…