irving cruz - Academia.edu (original) (raw)

Papers by irving cruz

physica status solidi c

The shape of size-controlled silicon nanocrystals (Si NCs) embedded in SiO 2 6 is investigated by... more The shape of size-controlled silicon nanocrystals (Si NCs) embedded in SiO 2 6 is investigated by tomographic energy-filtered transmission electron micros-7 copy (EFTEM). The sphericity of the quantum dots is determined by 8 computational analyses. In contrast to other fabrication methods, we 9 demonstrate that the NCs in superlattices are non-agglomerated, individual 10 clusters with slightly oblate spheroidal shape. This allows for low surface-to-11 volume ratios and thereby low non-radiative defect densities as required by 12 optoelectronic or sensing applications. A near-spherical shape is also a 13 prerequisite for the direct comparison of Si quantum dots (QDs) with 14 theoretical simulations. 15 1. Introduction 16 Silicon nanocrystals feature a tunable bandgap depending on 17 their size and efficient luminescence in the visible and near-18 infrared spectrum. Applications of Si NCs are envisaged in 19 various fields, for instance as optoelectronic material in Si-based 20 light emitters, [1,2] as sensor material with optical readout, [3] or as

Acta Universitaria, 2019

Bio-CAD and in-silico experimentation currently have a growing interest in biomedical application... more Bio-CAD and in-silico experimentation currently have a growing interest in biomedical applications where scientific data coming from real samples are used to evaluate physical properties. In this sense, analyzing the pore-size distribution is a demanding task to help interpret the characteristics of porous materials by partitioning it into its constituent pores. Pores are defined intuitively as local openings that can be interconnected by narrow apertures called throats that control a non-wetting phase invasion in a physical method. There are several approaches to characterize the pore space in terms of its constituent pores, several of them requiring prior computation of a skeleton. This paper presents a new approach to characterize the pore space, in terms of a pore-size distribution, which does not require the skeleton computation. Throats are identified using a new decomposition model that performs a spatial partition of the object in a non-hierarchical sweep-based way consistin...

Journal of Computational Science, 2018

A method to define the orientation based on Oriented Bounding Boxes (OBB).  Compute an OBB using... more A method to define the orientation based on Oriented Bounding Boxes (OBB).  Compute an OBB using the Extreme Vertices Model (EVM).  An EVM-based method to compute a true 3D roundness index.  Study of correlation between the developed methods and those reported in the literature.  A complete analysis of a real silica nano dataset applying the proposed methods.

Computación y Sistemas, 2017

This paper presents in detail the Compact Union of Disjoint Boxes (CUDB), a decomposition model f... more This paper presents in detail the Compact Union of Disjoint Boxes (CUDB), a decomposition model for binary volumes that has been recently but briefly introduced. This model is an improved version of a previous model called Ordered Union of Disjoint Boxes (OUDB). We show here, several desirable features that this model has versus OUDB, such as less unitary basic elements (boxes) and thus, a better efficiency in some neighborhood operations. We present algorithms for conversion to and from other models, and for basic computations as area (2D) or volume (3D). We also present an efficient algorithm for connected-component labeling (CCL) that does not follow the classical two-pass strategy. Finally we present an algorithm for collision (or adjacency) detection in static environments. We test the efficiency of CUDB versus existing models with several datasets.

Graphical Models, 2014

ABSTRACT This paper presents a new approach to simplify 3D binary images and general orthogonal p... more ABSTRACT This paper presents a new approach to simplify 3D binary images and general orthogonal pseudo-polyhedra (OPP). The method is incremental and produces a level-of-detail sequence of OPP, where any object of this sequence bounds the previous objects and, therefore, is a bounding orthogonal approximation of them. The sequence finishes with the axis-aligned bounding box. OPP are encoded using the Extreme Vertices Model, a complete model that stores a subset of their vertices and performs fast Boolean operations. Simplification is achieved by using a new strategy, which relies on the application of 2D Boolean operations. We also present a technique, based on model continuity, for better shape preservation. Finally, we present a data structure to encode in a progressive and loss-less way the generated sequence. Tests with several datasets show that the proposed method produces smaller storage sizes and good quality approximations compared with other methods that also produce bounding objects.

Lecture Notes in Computer Science, 2013

A new approach to simplify orthogonal pseudo-polyhedra (OPP) and binary volumes is presented. The... more A new approach to simplify orthogonal pseudo-polyhedra (OPP) and binary volumes is presented. The method is incremental and produces a level-of-detail (LOD) sequence of OPP. Any object of this sequence contains the previous objects and, therefore, it is a bounding orthogonal approximation of them. The sequence finishes with the minimum axis-aligned bounding box (AABB). OPP are represented by the Extreme Vertices Model, a complete model that stores a subset of their vertices and performs fast Boolean operations. Simplification is achieved using a new approach called merging faces, which relies on the application of 2D Boolean operations. We also present a technique, based on the model continuity, for a better shape preservation. The method has been tested with several datasets and compared with two similar methods.

Graphical Models, 2011

Analyzing the pore-size distribution of porous materials, made up of an aggregation of interconne... more Analyzing the pore-size distribution of porous materials, made up of an aggregation of interconnected pores, is a demanding task. Mercury intrusion porosimetry (MIP) is a physical method that intrudes mercury into a sample at increasing pressures to obtain a poresize histogram. This method has been simulated in-silice with several approaches requiring prior computation of a skeleton. We present a new approach to simulate MIP that does not require skeleton computation. Our method is an iterative process that considers the diameters corresponding to pressures. At each iteration, geometric tests detect throats for the corresponding diameter and a CCL process collects the region invaded by the mercury. Additionally, a new decomposition model called CUDB, is used. This is suitable for computing the throats and performs better with the CCL algorithm than a voxel model. Our approach obtains the pore-size distribution of the porous medium, and the corresponding pore graph.

Journal of Thermal Analysis and Calorimetry, 2012

This article establishes the relationship between the chemical composition, temperature and visco... more This article establishes the relationship between the chemical composition, temperature and viscosity of glasses obtained from the four sludge treatment plants of urban and industrial wastewater from the Nile Delta in Egypt. In order to determine the working conditions of these glasses and their growth temperature, different techniques have been used: differential thermal analysis, hot stage microscopy and dilatometry. We used a prototype of hot stage microscopy, with the help of an image analysis programme developed in the present study. The chemical composition of major oxides sludge ranging from: SiO 2 (36-48 wt%), Al 2 O 3 (9-16 wt%), CaO (5-25 wt%), P 2 O 5 (1.5-11 wt%), and Fe 2 O 3 (*9 wt%), this composition is close to a basalt rock, being necessary to incorporate some raw materials to adjust it to the basalt rock that has a good viscosity-temperature curve. The glass transition temperatures of the four glasses obtained vary between 650 and 725°C and the growth occurs between 938 and 1,033°C. We also obtained the viscosity-temperature curves with the aid of the hot stage microscopy that has allowed us to determine the working temperatures of the four glasses, ranging from 926 to 1,419°C, depending on the type of forming process used.

Proceedings of the International Conference on Computer Graphics Theory and Applications, 2012

This work presents a new approach to simplify objects. It is restricted to orthogonal pseudo-poly... more This work presents a new approach to simplify objects. It is restricted to orthogonal pseudo-polyhedra (OPP) and binary volumes. The method produces a level-of-detail (LOD) sequence of OPP and it is incremental. Any object in this sequence is a bounding OPP of the previous objects. The sequence finishes with the minimum axis-aligned bounding box. OPP are represented by the Extreme Vertices Model. Simplification is achieved using a new approach called merging faces that relies on the application of 2D Boolean operations.