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Öğe An interval type-2 fuzzy ELECTRE approach for assessing ballast water treatment systems for ships(Springer Science and Business Media Deutschland GmbH, 2024) Bashan, Veysi; Demirel, Hakan; Kaya, AhmetThe transportation of dangerous aquatic organisms and pathogens in ballast tanks causes problems on a global scale and therefore, The International Maritime Organization (IMO) has put into force the “International Convention for the Control and Management of Ships’ Ballast Waters and Sediments”. There are many ballast water treatment systems (BWTS) available in the market. The most important issue in the integration of the systems to the ships is to have technical information about the available options and to determine the most suitable solution for the ship among these alternatives. For this, the interested parties need to make an appropriate choice by knowing the features, advantages, and disadvantages of the BWTSs. The main aim of this article is to assess the five types of BWTS technologies that are frequently used and to make an optimum choice by consulting the opinions of experts in the sector. In this context, this study used the fuzzy ELECTRE (ELimination Et Choix Traduisant la REalite’) method and proposed a novel approach for handling BWTS selection based upon interval type-2 fuzzy sets. It has been evaluated that a hybrid system in which filtration + ultrasound + ultraviolet (UV) systems can be used together would be more appropriate. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Öğe Application fuzzy DEMATEL methodology to investigate some technical parameters of biochemical methane potential (BMP) test produced vegetable waste anaerobic biogas(Springer, 2022) Bashan, Veysi; Cetinkaya, Afsin Y.As the transition to renewable energy systems is accelerating, anaerobic digestion, which is one of the methods of energy recovery from organic substrates, continues to be studied with great interest by scientists. Anaerobic digestion research and applications are mostly carried out with biochemical methane potential (BMP) tests to decide the methane potency of sewage sludge, energy crops, and organic wastes. Unlike long and costly continually reactor experiments, actually, BMP tests are cumulative and can be performed with a relatively low investment of materials, technical labor, and also time. For the BMP to give accurate results, the effect of all the tools and technical parameters used in the implementation of the BMP should be well understood. In such situations, it is very useful to apply fuzzy logic methods in multi-criteria decision-making stages when more than one parameter changes at the same time. Therefore, in this study, fifteen parameters were determined and analyzed with the fuzzy DEMATEL (decision-making trial and evaluation laboratory) method to understand the cause-effect mechanism of the technical parameters of BMP. As a result of these analyses, it was seen that the material of the reactor (r(i)-c(j) value of 0.55), the particle size (r(i)-c(j) value of 0.43), the effect of mixing (r(i)-c(j) value of 0.32), and the amount of the total solids (TSA) value of 0.25) had a high effect in the causal sense. It was observed that the first-order parameter (material of reactor) was 27% stronger than the second-order (the particle size) parameter in terms of causality. Likewise, the second-order parameter is 34% stronger than the third-order parameter (the effect of mixing) in terms of cause effect. In addition, it was understood that the most effective parameters in the mechanism of effect were pH (r(i) +c(j) value of 3.41), C/N ratio (r(i)-c(j) value of 3.26), and temperature (r(i)-c(j) value of 3.07), respectively. Besides, high methane yield is seen in mesophilic conditions. The average cumulative biogas yield of the reactor is 282.1 NmL/g VS. The highest percentage of methane formed in the biogas occurred on the 21st day. Briefly, this study is important to provide a facilitating way for researchers working on BMP to understand the causeeffect mechanism of system technical requirements.Öğe Comparative evaluation and selection of submarines with air-independent propulsion system(Pergamon-Elsevier Science Ltd, 2022) Bashan, VeysiConventional submarines produced to date can be more easily detected and exposed to attacks due to their visible, infrared, and radar signatures. Diesel-electric submarines need to come to a close surface at certain time intervals to charge their batteries and power their diesel generators with snorting systems. This situation causes submarines to face threats from land, sea, and air war elements. In order to reduce these threats, it is clear that there is a need for an innovative system in which the need for submarines to the surface is minimized and the timing of emergence is more flexible. To ensure this situation, airindependent propulsion systems have come to the fore from past to present and have gained more and more strategic importance. These air-independent systems significantly improve silent underwater time, and maneuverability and greatly contribute to maintaining the submarine's military stealth strategy. In this context, in this study, six different power system alternatives used as air-independent propulsion (AIP) submarine systems were evaluated, their advantages and disadvantages were compared, and alternatives were sorted by five experts in terms of nine important technical and economic criteria with the fuzzy VIKOR method. It has been seen that the propulsion power with the fuel cell system comes to the fore. The choice of a high power density fuel cell system for a submarine AIP system can allow for superior underwater range and durability and a minimal rate of instability and thermal signature than would be achievable from any heat engine. This will greatly expand the strategic advantage of AIP submarines. In this respect, this article can be a guide in understanding the critical technical features of submarines and in deciding between alternatives in submarine system selection. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Öğe Evaluation of critical problems of heavy fuel oil separators on ships by best-worst method(Sage Publications Ltd, 2022) Bashan, Veysi; Demirel, Hakan; Celik, ErkanIt is known that trade by ship is a cheaper way than airway, land, and rail trade. One of the most important reasons for this is that ships use heavy fuel oil (HFO), which is cheap but also poor quality fuel. This HFO used in ships needs to be cleaned with machines called separators (purifiers). Therefore, the separator is one of the vital auxiliary machines on the ship. A satisfactory separation should be done in order to get rid of the effects such as water in the fuel, sludge formation, pump ability, mixing of different grades in the tanks, abrasion, and corrosion, which are the most important risks in the burning of fuel oil. Many problems are encountered while trying to make good separation. Therefore, in this article, 20 important problems that are frequently encountered in ship HFO separators are evaluated with the best-worst method (BWM) by consulting marine experts. Results show that dirty separator discs (also fractured or broken), wrong gravity disc choice (or bad interface position), and unsatisfactory bowl work are the most important problems among 20 critical and frequent separator problems. Problems and results are very important in terms of smooth ship machinery operations and we think that this study will close this gap in the literature by ordering and identifying problems and also solution recommendations.Öğe Experimental energy and exergy analyses of ship refrigeration system operated by frequency inverter at varying sea water temperatures(Springer Heidelberg, 2022) Yilmaz, Oktay; Bayar, Haydar; Bashan, Veysi; Yigit, KenanShip refrigeration compressors are sized to provide required capacity under extreme atmospheric and sea water temperatures, as well as full load and pulldown rates. Refrigeration compressors usually operate at 50-60 Hz in on/off mode at partial load in cold and temperate sea waters. The most efficient way to meet variable cooling demands is to change refrigerant mass flow by adjusting compressor speed. This paper is based on experimental investigation of ship cold storage refrigeration system on laboratory scale. Compressor is driven by inverter, and condenser is water-cooled type just like on ships. The refrigeration compressor has a power range of 600-1000 W and a maximum power of 1500 W. The system's refrigeration capacity ranges from 500 to 1350 W, with a maximum capacity of 2000 W. Experimental results were subjected to energy and exergy analyses. At 60 Hz, exergy efficiencies of compressor, condenser, expansion valve, and cold storage are 37.9%, 91.1%, 86.2%, and 69.8%, at - 5 degrees C cold storage and 18 degrees C water temperatures. In the same order, they contributed 73.2%, 7.6%, 10.4%, and 7% to wasted power. When water temperature increased from 18 to 35 degrees C at - 5 degrees C storage temperature and 50 Hz, coefficient of performance (COP) decreased by 55.2%. Despite compressor's thermodynamic irreversibility decreasing, combined electrical-mechanical efficiency deteriorated as frequency decreased. When compressor frequency was reduced from 60 to 40 Hz at - 5 degrees C cold storage and 18 degrees C water temperatures, COP increased by 13.9%.Öğe Health, safety, and environmental failure evaluation by hybridizing fuzzy multi-attribute decision-making methods for maritime scrubber systems(Springer, 2022) Bashan, Veysi; Yucesan, Melih; Demirel, Hakan; Gul, MuhammetMany shipping companies have started using scrubbers in their fleet to eliminate sulfur emissions from ships, per IMO (International Maritime Organization) rules. Before and during the scrubbers' selection, the scrubbers' operational failures have also started to appear and cause serious concerns. In this study, classified scrubber types are explained and open type, closed type, and hybrid scrubber systems are evaluated. To contribute to this gap in the literature, scrubber failures were identified, five experts with different perspectives were consulted, and the most common and critical malfunctions were evaluated with the fuzzy best-worst method (F-BWM) and fuzzy technique for order preference by similarity to an ideal solution (F-TOPSIS). F-BWM was used to determine the importance weights of the risk parameters used in evaluating failures since it provides fewer comparisons among pairwise comparison-based decision-making methods and a more consistent judgment in the evaluation. F-TOPSIS, on the other hand, was used to determine the final priority scores of the scrubber failures, taking into account the risk parameter weights obtained in the first stage. It has been preferred due to its easy to useness and based on its closeness to the ideal solution and applicability to risk and failure analysis problems. Considering all different systems in general, important issues such as collection efficiency, sulfur emission problem, abrasion, leakages, pump failures, heat exchanger failures, air fan sealing failures, sensors and failures in monitoring the whole system have been investigated. Results show that too high axial velocity for separator and flooded separator, too high solids concentration in recirculation liquid (SF2), piping leakages (SF5), poor quality or inappropriate consumables and chemicals (SF11), and feed circulation pump problems (SF6) are found to be the most important problems among thirteen failures.Öğe Influential Publications and Bibliometric Approach to Heavy Metal Removals for Water(Springer Int Publ Ag, 2022) Bashan, Veysi; Cetinkaya, Afsin Y.Heavy metals are elements that can have toxic effects even at low concentrations. Heavy metal pollution is one of the most concerning issues at the global level because of the health risks it causes and its negative effects on the ecosystem. Many studies have been carried out in the past years to reduce heavy metal emissions, pollution, and their effects on health. In this context, a scientometric study was conducted to show how this topic has developed academically and to identify effective studies in the field of heavy metal removals for water. When the Web of Science (WoS) database is searched, a total of 22,911 articles were collected based on the heavy metal removals for water subjects, and then, articles were sorted and the top 100 most cited articles were determined. By determining the top 100 most cited articles on this subject, bibliometric analysis has been carried out by covering co-occurrence, co-citation analysis, cluster analysis, and much more. When these top 100 most cited articles were examined, it was seen that review articles were in the majority (59%), and there were more studies in environmental sciences, engineering environmental, engineering chemical, biotechnology applied microbiology categories. It has been observed that most of these most cited articles were published between 2007 and 2012, and the citations given to these 100 articles increased almost linearly since 2007. In addition, it has been determined that China ranks first in this regard with 23 articles and 21,137 citations. The working network between countries, institutes/universities has been revealed. It was determined that the words adsorption, heavy metals, and waste were used the most among the keywords. This study is expected to lay the groundwork for future discussions on the subject. Our analysis provides information on technology and informs decision-makers and researchers about the value of new and existing technologies and future opportunities.Öğe Predicting tanker main engine power using regression analysis and artificial neural networks(Yildiz Technical Univ, 2023) Gunes, Umit; Bashan, Veysi; Ozsari, Ibrahim; Karakurt, Asim SinanThe purpose-oriented design and planning of ships is maintained throughout production. Outer form of ship equipment starts with the steel construction process. The outer body production process moves ahead with painting, quality control tests, and bureaucratic procedures. In accordance with all these form and block operations, choosing a main engine suitable for all other technical parameters is vital, especially regarding ship speed and the amount of cargo it will carry. As a result, estimating main engine power is attempted with the help of artificial neural network (ANN) and regression analyses by considering a ship's technical parameters (e.g., draught, depth, deadweight tonnage [DWT], gross tonnage [GT], and engine power). This study conducts regression and ANN analyses over 836 tanker ships from the Marine Traffic database to predict main engine power using input parameters (deadweight (DWT), Length (L), Breadth (B), and gross ton (GT) values). The regression analyses show Model7 to perform the best approximation with a determination value = 0.827 usable for estimating main engine power. After all the examinations, a very accomplished result of 0.98047 was additionally obtained from the ANN analysis. The study makes beneficial and innovative contributions to predicting tankers' required main engine power.
