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Myocardial segmentation using constrained multi-seeded region growing
Multi-slice short-axis acquisitions of the left ventricle are fundamental for estimating the volume and mass of the left ventricle in cardiac MRI scans. Manual segmentation of the myocardium in all time frames per each cross-section is a cumbersome task. Therefore, automatic myocardium segmentation methods are essential for cardiac functional analysis. Region growing has been proposed to segment the myocardium. Although the technique is simple and fast, non uniform intensity and low-contrast interfaces of the myocardium are major challenges of the technique that limit its use in myocardial
Mechanical behavior optimization of chitosan extracted from shrimp shells as a sustainable material for shopping bags
The use of biodegradable materials for shopping bag production, and other products made from plastics, has recently been an object of intense research-with the aim of reducing the environmental burdens given by conventional materials. Chitosan is a potential material because of its biocompatibility, degradability, and non-toxicity. It is a semi-natural biopolymeric material produced by the deacetylation of chitin, which is the second most abundant natural biopolymer (after cellulose). Chitin is found in the exoskeleton of insects, marine crustaceans, and the cell walls of certain fungi and
Layer-by-layer preparation and characterization of recyclable nanocomposite (CoxNi1−xFe2O4; X = 0.9/SiO2/TiO2)
Titanium dioxide (TiO2) nanocomposites have been extensively employed in many fundamental optoelectronic and photocatalytic applications due to their outstanding optical, electronic and chemical properties. In the present work, we introduce a simple layer-by-layer approach to design a magnetic TiO2 nanocomposite that could be easily recycled using an external magnetic field without affecting its quantum efficiency. The crystallinity, size, surface area, stability, morphology, purity and other optical, thermal and magnetic properties of the composite have been investigated. Surface topology
Advanced materials and technologies for supercapacitors used in energy conversion and storage: a review
Supercapacitors are increasingly used for energy conversion and storage systems in sustainable nanotechnologies. Graphite is a conventional electrode utilized in Li-ion-based batteries, yet its specific capacitance of 372 mA h g−1 is not adequate for supercapacitor applications. Interest in supercapacitors is due to their high-energy capacity, storage for a shorter period and longer lifetime. This review compares the following materials used to fabricate supercapacitors: spinel ferrites, e.g., MFe2O4, MMoO4 and MCo2O4 where M denotes a transition metal ion; perovskite oxides; transition metals
Incremental Grounded Voltage Controlled Memristor Emulator
Memristor has become an interesting research subject in the recent years. Its special behavior has attracted the attention of the research community that motivated researchers to investigate it in details. As memristor is a relatively new electrical element, it is not yet available in the market as a solid state component Researchers found their way to build memristor emulators to achieve its pinched hysteresis. While many papers proposed floating emulators, only a few papers presented a grounded one. In this paper, an incremental grounded memristor emulator is proposed. The mathematical model
Implementation of a Pulsed-Wave Spectral Doppler Module on a Programmable Ultrasound System
Pulsed wave Doppler ultrasound is commonly used in the diagnosis of cardiovascular and blood flow abnormalities. Doppler techniques have gained clinical significance due to its safety, real-time performance and affordability. This work presents the development of a pulsed wave spectral Doppler module, which was integrated into a reconfigurable ultrasound system. The targeted system adopts a hardware-software partitioning scheme where an FPGA handles the front-end and a PC performs the back-end. Two factors were considered during the design. First, the data transfer rate between hardware and
Design of fopid controller for a dc motor using approximation techniques
This paper introduces a study of fractional-order PID (FOPID) controller applied to a DC motor. The idea is to control the motor speed using the FOPID and compare it with the conventional PID controller. Two approximation techniques are employed to realize the FOPID, which are Matsuda and Oustaloup, each with order four. Different responses are depicted for various fractional orders. A specific case study for controlling the speed of a DC motor is investigated with selected fractional-orders. A comparison between the two applied techniques is proposed on the case study to determine which
Optimization of fractional-order RLC filters
This paper introduces some generalized fundamentals for fractional-order RL β C α circuits as well as a gradient-based optimization technique in the frequency domain. One of the main advantages of the fractional-order design is that it increases the flexibility and degrees of freedom by means of the fractional parameters, which provide new fundamentals and can be used for better interpretation or best fit matching with experimental results. An analysis of the real and imaginary components, the magnitude and phase responses, and the sensitivity must be performed to obtain an optimal design
Chaotic properties of various types of hidden attractors in integer and fractional order domains
Nonlinear dynamical systems with chaotic attractors have many engineering applications such as dynamical models or pseudo-random number generators. Discovering systems with hidden attractors has recently received considerable attention because they can lead to unexpected responses to perturbations. In this chapter, several recent examples of hidden attractors, which are classified into several categories from two different viewpoints, are reviewed. From the viewpoint of the equilibrium type, they are classified into systems with no equilibria, with a line of equilibrium points, and with one
Two-dimensional front-tracking model for film evaporation
To understand the physical process involved in film evaporation, a new numerical model is created using coupled quadratic finite element formulation of the conservation equations. The heat transport equation is solved in the three different phases (solid, liquid and vapor) while the Navier-Stokes equation are solved in the two fluids. The gradient discontinuity at the liquid vapor interface provides local value of the evaporative flux density that is directly linked to the interface velocity jump through mass conservation principle and used as boundary condition for two fluid flow computations
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