Sharif Digital Repository

The fish freshness was evaluated using machine vision technique through color changes of eyes and gills of farmed and wild gilthead sea bream (Sparus aurata), being employed lightness (L*), redness (a *), yellowness (b*), chroma (c *), and total color difference (ΔE) parameters during fish ice storage. A digital color imaging system, calibrated to provide accurate CIELAB color measurements, was employed to record the visual characteristics of eyes and gills. The region of interest was automatically selected using a computer program developed in MATLAB software. L*, b *, and ΔE of eyes increased with storage time, while c* decreased. The a* parameter of fish eyes did not show clear a trend... 

This paper addresses the issues of energy efficiency in robotic fish design by use of hydrodynamic models. The use of LighthilPs small-amplitude elongated body theory for designing of robotic fish, obtaining optimal kinematics and dynamic analysis with emphasis on compliant mechanism is presented. Simulation results for a sample case have demonstrated the importance of proposed approach in robotic fish design. Copyright © 2008 by ASME  

Experimental hydrodynamics imaging of four Pangasius sanitwongsei were considered. A quantitative characterization of caudal fin is presented in this article. Steady swimming of four P. sanitwongsei with different total length was studied experimentally and taped by high-speed digital video, and undulatory movement of each fish at different velocity was revealed. The pattern of body undulatory movement of the fish was drawn from the video images. Three main factors that determine the fish swimming behavior are Reynolds number, Strouhal number and shape. In this study, Lf/L was chosen as a characteristic of shape, where Lf was the distance from the start of the head to the end of the head.... 

Four 5-, 10-, 20- and 30-story moment frames, representing low-, mid-, and two high-rise structures, were subjected to a great number of idealized directivity pulses. The amplitudes and periods of pulses vary from 0.02 g to 1.0 g and 0.5 to 12 sec, respectively. Over 1400 nonlinear dynamic analyses of low- to high-rise moment frames were performed which were feasible through using modified fish-bone model. The distribution of interstory drift along the height was studied and two applied contours were proposed: (i) the maximum interstory drift contour, and (ii) the critical story contour. These contours were demonstrated versus the ratio of natural period of the structure to the pulse period... 

In this paper, hydrodynamic simulation of fish-like swimming for two types of aquatic animals including tuna fish and giant danio is presented. We employ an unsteady three-dimensional inviscid boundary element method including time stepping algorithm to capture the wake sheet and flow features around swimming fish in a straight course. At each time step, an unsteady Bernoulli equation was used to find the pressure distribution and thrust generated by the animal. To couple fluid solver with kinematic equations of flexible body, undulating motions of backbone were defined using a prescribed continuous function. Although the flexible motion mechanism controls the fish swimming but no structural... 

On July 24th, 2010, several explosions and fires devastated a hydrocarbon processing plant in Kharg Island, Iran. Four workers were killed and many others were severely injured. The plant became out of service for 80 days. The way the accident happened and its sequence was representing as a domino accident. In this paper, events leading up to the disaster have been analyzed in details. Graphic presentation techniques such as Fish Bone Analysis and Event Sequence Diagram (ESD) have been utilized to enhance the understanding of the accident mechanism. Finally major lessons learnt from this domino accident have been addressed  

Gelatin is a denatured protein derived from collagen by thermohydrolysis and has a rheological property of thermo reversible transformation between sol & gel. Gelatin is one of the most important biopolymers, with widespread applications in the food, pharmaceutical, cosmetic and photographic industries. Gelatin is commercially made from skins and skeletons of bovine and porcine and mammalian gelatin has been intensively studied. However, mammalian gelatin is at risk for contamination with bovine spongiform encephalopathy and increase in demand for kosher and halal foods have created a demand for fish gelatin for food applications. Therefore, the objective of this study was to extract gelatin... 

This study investigates the roll decay of a fishing vessel by experiments and computational fluid dynamics (CFD) simulations. A fishing vessel roll decay is tested experimentally for different initial roll angles. The roll decay is also simulated numerically by CFD simulations and is validated against the experimental results. It shows that the roll damping could be obtained by CFD with high level of accuracy. The linear and nonlinear damping terms are extracted from the CFD roll decay results and are used in a potential-based solver. In this way we are using a hybrid solver that benefits the accuracy of the CFD results in terms of roll damping estimation and the fast computations of the... 

In the present study, an adaptive sliding mode control method was employed to control a fish robotic system using hardware in the loop methodology. Up to now, few researches have focused on autonomous control of fish robot in dynamic environments which may be the result of difficulties in modeling of hydrodynamic effects on fish robot. Therefore, following the introduction of the nonlinear model for the robot, elongated body theory, suggested by Lighthill, was used to analyze fish movements. Then, kinematics control to track desired trajectories was designed for under-actuated model of robot. Adaptive sliding mode controller, capable of adapting according to changes and uncertainties, was... 

Design of robotic fish based on hydrodynamics is presented and Lighthill's Large Amplitude Elongated Body Theory (LAEBT) is used for modeling of the robotic fish in linear path. A PID controller for control of speed in linear path is designed and simulations are presented which shows its effectiveness for speed control of the robotic fish. It has been shown that in perspective of used approximate LAEBT model, the used control law maintains kinematic parameters and therefore, the associated efficiency will be maintained  

The seismic risk framework of building structures has been presented to reduce earthquake-induced adverse consequences. In this context, probabilistic analysis of engineering demand parameters (EDPs) is always associated with many uncertainties and high computational demand for use in practical applications. This study has been presented to efficiently estimate the distribution of EDPs in probabilistic seismic risk assessment of irregular steel moment-resisting frames (SMRFs). For this purpose, the incorporation of the consistent fish-bone (CFB) model and the endurance time (ET) analysis method has been used. The proposed method (i.e., CFB-ET) has a substantial impact on reducing the... 

The seismic risk framework of building structures has been presented to reduce earthquake-induced adverse consequences. In this context, probabilistic analysis of engineering demand parameters (EDPs) is always associated with many uncertainties and high computational demand for use in practical applications. This study has been presented to efficiently estimate the distribution of EDPs in probabilistic seismic risk assessment of irregular steel moment-resisting frames (SMRFs). For this purpose, the incorporation of the consistent fish-bone (CFB) model and the endurance time (ET) analysis method has been used. The proposed method (i.e., CFB-ET) has a substantial impact on reducing the... 

The seismic risk framework of building structures has been presented to reduce earthquake-induced adverse consequences. In this context, probabilistic analysis of engineering demand parameters (EDPs) is always associated with many uncertainties and high computational demand for use in practical applications. This study has been presented to efficiently estimate the distribution of EDPs in probabilistic seismic risk assessment of irregular steel moment-resisting frames (SMRFs). For this purpose, the incorporation of the consistent fish-bone (CFB) model and the endurance time (ET) analysis method has been used. The proposed method (i.e., CFB-ET) has a substantial impact on reducing the... 

This study aims to develop the Consistent Fish-Bone (CFB) simplified model for efficient estimation of Engineering Demand Parameters (EDPs) in irregular steel Moment Resisting Frames (steel-MRFs). To achieve this goal, some modifications based on the energy consistent approach have been applied to the Improved Fish-Bone (IFB) simplified model previously presented for reinforced concrete MRFs. These modifications include: 1) adding truss elements to the IFB model to consider the effect of flexural deformations and determining their areas by balancing the overturning moment and the strain energy due to the axial deformation of columns in the original steel-MRF with the overturning moment and...