Search results for "Single point"
showing 7 items of 37 documents
Validation of a method for measuring the retinal thickness with Shack–Hartmann aberrometry in an artificial eye
2015
In Shack–Hartmann aberrometry, it is assumed that a wave front emerges from a single point focused on a retina. However, the retina is a multi-layered structure and reflections may occur from several layers. This may result in several overlapping spot patterns on the CCD due to different vergences of the outgoing wave fronts. The amount by which these spot patterns are displaced may contain information about the retinal thickness. In this study, we perform simulations of formation of double spots in a living eye and also apply this method to measure the thickness of an artificial retina with a simple structure. We also compare the results obtained with artificial eye and compare them to the…
FEM Simulation of Laminated Lightweight Materials Processed through Single Point Incremental Forming
2015
The aim of present paper is to realize the FEM simulation of laminated lightweight material processed through single point incremental forming. Thus a laminated material, aluminum - polypropylene - aluminum (Al-PP-Al), as sheet 1.2 mm thickness was used. For these material the hardening curve was determinate. These values were used to describe elastic-plastic behavior of the material during single point incremental forming process simulation. Single point incremental forming process simulation aimed to assess the distribution of values and maximum and minimum strains, the material thickness of the specimen and the technological force for the two strategies for obtaining the truncated cone s…
Incremental forming using KUKA KR210-2 industrial robot - research regarding design rules and process modelling
2021
Incremental sheet forming (ISF) process show a great potential in the manufacturing of small series production or prototype development parts. One of the sheet metal forming process, where the contact between punch and metal sheet is in a single point, is known as single point incremental forming (SPIF). The part is manufacture with a simple tool, known as punch, that performs a series of combined movements on the vertically and horizontally directions. The paper introduces a study regarding the design rules and process modelling of this unconventional process, by means of a KUKA KR210-2 industrial robot as technological equipment able to control the correlated movement of the punch. Supple…
A theoretical study on the decomposition mechanism of β-propiolactone and β-butyrolactone
1998
Abstract The reaction mechanism associated with the decomposition of β-propiolactone and β-butyrolactone in the gas phase to form carbon dioxide and ethylene or propene, respectively, has been theoretically characterized by using analytical gradients at the B3LYP/6-31G**, B3LYP/6-31++G**, MP2/6-31G** and MP2/6-31++G** calculation levels, as well as by single point calculations at QCISD(T)/6-31++G**//MP2/6-31++G**. A detailed analysis of the results points out that the reaction pathway can be described as an asynchronous concerted process. The geometrical parameters and the components of the transition vector are weakly dependent on the computational method. By applying transition state theo…
RESHAPING AS NOVEL CIRCULAR ECONOMY STRATEGY FOR SHEET METAL BASED END-OF-LIFE COMPONENTS
2022
Making materials consumes about 21% of the global energy demand a specifically metals production, it accounts for about 8% of total global energy consumption. In fact, in the past few decades, the use of lightweight alloys has become increasingly widespread in many major industrial sectors thanks to the weight reduction associated with their applications. Most lightweight materials like aluminum alloys are characterized by high-energy demands primary production cycles that are responsible for a relevant share of the global CO2 emissions. Circular economy strategies such us longer life, more intense use, repair, product upgrades, modularity, remanufacturing, component re-use and open/closed …
Comparison of two different approaches for harmonic distortion sources assessment
2021
The paper focuses the attention on the comparison of two approaches for power quality assessment in the electric grid. Both approaches are suitable for investigating the harmonic pollution source and discovering if the harmonic source comes from the customer or the utility grid. The two approaches have the same purpose but they are deeply different. The first approach is based on the knowledge of the customer and utility equivalent impedance while the second is based on single point measurement at point of common coupling PCC. In this paper, the advantages and drawbacks of the two approaches are investigated also supported by a case study.
A Kalman filter single point positioning for maritime applications using a smartphone
2020
Different positioning techniques have been largely adopted for maritime applications that require high accuracy kinematic positioning. The main objective of the paper is the performance assessment of a Single Point Positioning algorithm (SPP), with a Kalman filter (KF) estimator, adapted for maritime applications. The KF has been chosen as estimation technique due to the ability to consider both the state vector dynamic and the measurements. Particularly, in order to compute an accurate vertical component of the position, suitable for maritime applications, the KF settings have been modified by tuning the covariance matrix of the process noise. The algorithm is developed in Matlab environme…