Sharif Digital Repository

The unbounded linearly increasing responses in galloping instability make sharp-edge oscillators a beneficial solution for bladeless energy harvesting. While the performance of single square oscillators has been the subject of several studies in the past, there is still little knowledge about their hydrokinetic energy performance in tandem configurations. An optimal oscillator should display high performance in a group when all bodies are free to harness energy. In this study, the energy harvesting performance of square oscillators is examined in multiple tandem configurations under free and fixed square wakes. The harmonic oscillator model is coupled with the electromagnetic transducer to... 

This in-water experimental study deals with the effects of the after-body on the FIV response of round and sharp edge cylinders. Different circular, square, diamond, and right-angle isosceles triangular cross-sections are investigated. The triangular cylinder is examined in four different symmetrical and unsymmetrical configurations with respect to the incident flow. The current towing tank experiments form a basis for the feasibility study of the isosceles triangular cylinders for FIV energy converters. The results indicate that the cylinders with a flat side perpendicular to the flow have a galloping type of response. In contrast, the cylinders with a sharp vertex pointing the flow show a... 

The global demand for renewable energy sources has arisen significant research interests in marine hydrokinetic energy harvesting from flow induced vibrations. The current study deals with the hydrokinetic energy harvesting potentials of diamond and square oscillators at various inline configurations. Both the sharp edge sections and the wake induced vibrations in tandem arrangement can lead to galloping type of instability with high energy efficiency ratios. The present in-water towing tank experiments comprise 1DoF vibrating systems at Re ranging from 2 × 103 to 4.8 × 104. The results show that the upstream wake generally enhances the system efficiency and the mechanical work done by the... 

This in-water experimental study deals with the effects of the after-body on the FIV response of round and sharp edge cylinders. Different circular, square, diamond, and right-angle isosceles triangular cross-sections are investigated. The triangular cylinder is examined in four different symmetrical and unsymmetrical configurations with respect to the incident flow. The current towing tank experiments form a basis for the feasibility study of the isosceles triangular cylinders for FIV energy converters. The results indicate that the cylinders with a flat side perpendicular to the flow have a galloping type of response. In contrast, the cylinders with a sharp vertex pointing the flow show a... 

Nowadays, embedded processors are widely used in wide range of domains from low-power to safety-critical applications. By providing prominent features such as variant peripheral support and flexibility to partial or major design modifications, field-programmable gate arrays (FPGAs) are commonly used to implement either an entire embedded system or a hardware description language-based processor, known as soft-core processor. FPGA-based designs, however, suffer from high power consumption, large die area, and low performance that hinders common use of soft-core processors in low-power embedded systems. In this paper, we present an efficient reconfigurable architecture to implement soft-core... 

Learning a foreign language encompasses a process of trial and error that can lead to the progression of the learner's interlanguage, meaning that the learners make use of their language knowledge that receives feedback and brings about progress through diagnosis of the problems and being corrected by the teacher. Therefore, there exists a need to analyze the underlying reasons causing the students to remain taciturn with a low willingness to communicate (WTC) during a language class. There has been much work done investigating the role of the learner's stable personal characteristics (traits) along with their situational changes at a specific time (states) that influence the student's... 

Using 3-D scanned data to analyze and extract pore network plays a vital role in investigation of porous media's characteristics. In this paper, a new simple method is developed to detect pores and throats for analyzing the connectivity and permeability of the network. This automated method utilizes some of the common and well-known image processing functions which are widely accessible by researchers and this has led to an easy algorithm implementation. In this method, after polishing and quality control of images, using city-block distance function and watershed segmentation algorithm, pores and throats are detected and 3-D network is produced. This method can also be applied on 2-D images... 

In this paper, we try to recognize and distinguish different groups of arrhythmia using novel features which have been obtained from the heart rate's phase space in recent years. For this purpose, we used Triangular Phase Space Mapping (TPSM) and Parabolic Phase Space Mapping (PPSM). For recognition, we used three groups of 15 subjects using the Physionet database (Arrhythmia, Congestive Heart Failure (CHF), and Atrial Fibrillation (AF)) with Normal Sinus Rhythm (NSR). The obtained features discriminate arrhythmia from NSR by p