فصلنامه علوم و فناوری دریا
سال بیست و پنجم شماره 98 (تابستان 1400)

One of the world's leading research on solar cells is about tracking maximum power. That is, scientists and researchers believe that by any means possible, with the lowest number of arrays in the solar panels, they will get the most solar energy from the panels and find the optimal point of radiation using smart algorithms. Environmental conditions cause changes in current, voltage and maximum power point in the photovoltaic panel. Therefore, in order to increase efficiency and reduce costs in the photovoltaic system, we need to control the photovoltaic panel at the maximum power point. The methods in terms of complexity, sensors are required, the convergence rate, cost, hardware and implement different models. In fact, there are so many people who can not be identified with certainty the most effective set them up for a photovoltaic system. In this paper, a generator is designed to increase the energy production of solar cells. Maximum power point tracking system of photovoltaic modules, boost converter and fuzzy controller for controlling the on-off switch MOSFET boost converter to maintain the output power of the photovoltaic array at the maximum power point Ast.lt formed using fuzzy controller in this paper, The rapid response is to environmental change. Also, changing the circuit will not affect its performance and ultimately very high efficiency to follow the maximum power point from 94.8% to 99.4% which confirms the simulation results mentioned above

Acoustic sensor networks are placed in underwater environment and have many applications in various industries like oil and gas. The lifetime of underwater nodes is the most important factor in design of these networks for data communications because battery replacement is usually difficult due to complicated technical issues of underwater sensors. Therefore, improving energy consumption is very important to reach the maximum lifetime of energy sources. Routing protocols can effectively help to reduce energy consumption. Here, we have done a systematic review on a class of routing techniques entitled physically-constrained protocols with 3D space zoning. This physical segmentation of the 3D underwater space is virtually done towards more efficient and energy-aware data forwarding in internet of underwater things (IoUT) platform.

In this study, using finite element simulation, the effect of seawater corrosion on the fatigue life of 5083 aluminum alloy welded by shielding gas method after turbulent friction process has been investigated. Plates with different dimensions of 49.1 to 49.8 cm3 were modeled and then simulated with conical corrosion attacks, having different diameters and heights and random distribution. Afterward, considering experimentally mechanical properties reported by other researchers, fatigue life was analyzed through ABAQUS software solver. The results of corrosion as well as material properties effects on fatigue life and also the effect corrosion of the useful life of the aluminum alloy were investigated. The results showed that by increasing the corrosion rate of aluminum alloy, it had less resistance to fatigue, so that by creating approximately 1.8% corrosion on the sample surface, a 5.6% reduction in cycle was achieved. The validation of the simulation results in corrosion fatigue analysis, obtained in the present study through the stress-life method, with the use of the results published by other researchers, reveals a good agreement.

Floating structures play an important role in exploring the oil and gas from the sea. The motion response of the structure should be kept within a certain range to prevent damage to the risers and transmission pipes and, most importantly, the oil processing system. In this study, vertical acceleration of semisubmersible platform was simulated under regular wave in AQWA software. The results were compared to experimental results done in the marine technology center of university technology Malaysia. Semi motions in six degrees of freedom subjected to regular wave were investigated in time and frequency domains. Damping coefficients, added masses and wave forces under different incident wave angles and finally response amplitude of operations (RAOs) was obtained in the frequency domain. By transferring the data to the time domain and solving, the vertical acceleration was obtained. Acceleration causes crew seasickness, the worst of which occurs during a 20-second period. The Surge RAO have the highest value in the 20-second period equal to 5.5 and the Yaw RAO have the lowest value of 0.032 in the 20.91-second period. Comparing the obtained results with the laboratory results, it can be seen that the simulation performed on the motion of the semi-submersible platform has an average error of 10.41%.

Bunkering is a vital part of our lifes. Supplying fuel or bunkering, as one of the most important components of maritime transport, has found its place in most parts of the world today.In this regard, Iran's effective entry into this industry can strengthen the country's political and economic sovereignty in the Persian Gulf and the Sea of Oman and lead to growth and development of activities, employment and income generation, development of existing ports and infrastructure and increase Iran's global reputation and complete the country's oil value chain. The hypotheses of this research are marketing mixture, Axial Strategy, political, external marketing and internal marketing.The purpose of this study is to identify the opportunities and challenges of the factors affecting the Iranian bunkering market from the experts point of view, with a quantitative approach.This research is an applied research in terms of purpose. The method of data collection is a Likert scale survey. Structural equation technique and AMOS software are used to analyze the data.Prioritization of criteria and sub-criteria is based on AHP technique.Finally, the output of Expert Choice software is used to implement and hierarchical cluster analysis.

The development and use of unmanned aerial vehicles has been very challenging, and the applicability of maritime law and international maritime conventions to them has been obscured. Despite the ability to use these devices in various scientific, exploratory, economic, political, military, etc. dimensions, but the legitimacy of their use in the light of international maritime documents is still disputed and determine the legal status of their use in The radiation of international maritime conventions is essential. At the same time, the rules of international law in question seem to have gaps in this area, and do not respond to their increasing development. The purpose of this brief is to examine the legal status of unmanned aerial vehicles as ships from the perspective of international maritime conventions, and the question that the author seeks to answer is whether unmanned aerial vehicles are capable of this. Do they have to be considered ships from the point of view of international maritime conventions? The research hypothesis is based on the assumption that unmanned aerial vehicles can be considered as ships if they are capable of floating and carrying. Research Method The present paper is an analytical-descriptive method. The method of data collection is the library method.