objectives: this study aimed to evaluate the effect of storage period on dimensional stability of alginplus and hydrogum 5. materials and methods: in this in vitro experimental study, 60 impressions were taken of an upper jaw typodont, including 10 impressions for each storage period to be tested (12 minutes, 24 and 120 hours) for each type of alginate. then, the impressions were stored in an i...

This paper presents optimal phasor measurement units (PMUs) placement algorithms for power system observability. The optimal placement problem (OPP) is formulated such that minimizing the number of PMU installations for full network observability. Three approaches, in this paper, are introduced aiming at reducing the computational burden in Optimal Placement problems. Depth First Search, Simula...

In the AUV binocular vision navigation, in order to improve the AUV positioning accuracy, optimizing the stereo vision imaging system structure and weighted least-square method is proposed. The principle of AUV location is analyzed, and that the AUV location accuracy depends on the measurement precision of the three dimensional space point is proposed. Based on the analysis of stereo vision mea...

The demand for measuring equipments of automatic optical inspection has grown rapidly, because of its benefits of promoted efficiency and higher precision. Instead of manual projection measurements, measurement performance and efficiency can be obviously enhanced by the image measurement system. In this investigation, digital image processing and geometrical measurement principles have been int...

The measurement of large forces and the presence of errors due to dimensional coupling are significant challenges for multi-dimensional force sensors. To address these challenges, this paper proposes an over-constrained six-dimensional force sensor based on a parallel mechanism of steel ball structures as a measurement module. The steel ball structure can be subject to rolling friction instead ...

acrylic resin denture bases undergo dimensional changes during polymerization. injection molding techniques are reported to reduce these changes and thereby improve physical properties of denture bases. the aim of this study was to compare dimensional changes of specimens processed by conventional and injection-molding techniques.sr-ivocap triplex hot resin was used for conventional pressure-pa...

In this paper, a two-dimensional multi-wavelet is constructed in terms of Chebyshev polynomials. The constructed multi-wavelet is an orthonormal basis for space. By discretizing two-dimensional Fredholm integral equation reduce to a algebraic system. The obtained system is solved by the Galerkin method in the subspace of by using two-dimensional multi-wavelet bases. Because the bases of subs...