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Search results for: WEATHER ROUTING MULTI-OBJECTIVE CONSTRAINED OPTIMIZATION SHIP SYNCHRONOUS ROLLING RESONANCE FREQUENCY OF ROLLING EQUIVALENT METACENTRIC HEIGHT NATURAL PERIOD OF SHIP ROLL
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A Fuzzy Event Tree Model for Accident Scenario Analysis of Ship Stuck in Ice in Arctic Waters
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A Method of Risk and Safety Assessment During the Ship Salvage Using the Hazard, Release and Consequence Analysis
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Numerical Analysis of the Unsteady Propeller Performance in the Ship Wake Modified by Different Wake Improvement Devices
PublicationThe paper presents summary of numerical analysis of the unsteady propeller forces and induced pressure pulses generated by the selected real propeller of 7000 tons product tanker, operating in five different wakefields including four inflenced by the different wake improvement devices. The results of the analysis are partly compared with experimental data and univocal conclusions about the optimum wake improvement device are presented.
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The application of an expert system for simulation investigations in yhe aided design of ship power systems automation.
PublicationPrzedstawiono strukturę i funkcje systemu wspomagającego projektowanie automatyki systemów enegretycznych statków. Dane opisujące projektowany podsystem energetyczny są wprowadzane w trybie interaktywnym do systemu ekspertowego. Reguły określaja poprawność formalną i merytoryczną wprowadzonych danych. W przypadku braku błędów system automatycznie tworzy model symulacyjny projektowanego podsystemu enegretycznego i wywołuje program...
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Problem of optimal load distribution between generators minimizing risk of enegretic ship system overload.
PublicationOmówiono system rozdziału mocy czynnych pomiędzy generatorami w systemie energetycznym statku. Minimalizuje się ryzyko przeciążeń systemu przy jednoczesnej minimalizacji kosztów wytwarzania energii w systemie.
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On possible lowering fuel oil consumption by differentiating loads on ship diesel engines running in parrallel.
PublicationPodano możliwości zmniejszenia zużycia paliwa przez silniki okrętowe pracujące równolegle dzieki różnicowaniu ich obciążeń eksploatacyjnych. Zaprezentowano podstawy teoretyczne oraz sposób postępowania przy pomiarach zużycia paliwa w czasie rzeczywistym.
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Conception of selecting reliability models for taking operating decisionsrelated to sea-going ship´s systems
PublicationPrzedstawiono możliwości podejmowania decyzji dotyczących sytuacji, gdy decydent dysponuje informacją aprioryczną o stanie technicznym urządzeń, na przykład uzyskaną z badań niezawodności urządzeń niezbędnych do wykonania zadania, wyrażoną w formie prawdopodobieństwa. Do opracowania modelu umożliwiającego podejmowanie takich decyzji eksploatacyjnych wykorzystano elementy bayesowskiej statystycznej teorii decyzji.
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A concept of pusher - barge coupling device of two-segment ship for inland waterways and coastal service
PublicationW artykule przedstawiono założenia projektowe i koncepcję rozwiązania konstrukcyjnego oraz napędu i sterowania urządzenia sprzęgającego pchacz i barkę dwusegmentowego statku śródlądowego i przybrzeżnego. Zaprezentowane urządzenie umożliwia zarówno sztywne połączenie, jak i wzajemne kontrolowane wychylanie obu segmentów względem siebie, co w znacznym stopni zwiększa manewrowość, a tym samym bezpieczeństwo żeglugi, zwłaszcza na wąskich...
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Design concepts of propulsion and steering system for hotel unit of two-segment inland waterways ship
PublicationW artykule przedstawiono założenia projektowe i dwa rozwiązania koncepcyjne napędu i sterowania barki hotelowej, stanowiącej część dwusegmentowego statku śródlądowego i przybrzeżnego. Obydwa rozwiązania oparto na zastosowaniu dziobowego śrubosteru małej mocy, ze śrubą stałą umieszczoną w dyszy obrotowej. W jednym z rozwiązań śruba napędzana jest silnikiem hydraulicznym, zaś w drugim - silnikiem elektrycznym. Mechanizm obrotu kolumny...
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Computational model for simulation of lifeboat motions during its launching from ship in rough seas
PublicationW artykule przedstawiono model obliczeniowy 3 D, opisujący ruch obiektu w 6 stopniach swobody (6DoF), do symulacji ruchu jedno- lub dwuzawiesiowej łodzi ratunkowej lub ratowniczej podczas opuszczania ze statku na wzburzonej wodzie. Jest to złożony model uwzględniający warunki morskie oraz elastyczność i własności tłumiące elementów i mechanizmów żurawika, liny oraz kadłuba łodzi. Ponadto przedstawiono przykładowe wyniki obliczeń...
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An integrated hydraulic drive system of a novel device for launching lifeboats from large passenger ship
PublicationArtykuł przedstawia zintegrowany układ napędu i sterowania hydraulicznego systemu ewakuacyjnego składającego się z wyciągu łańcuchowego z zamocowanymi na nim łodziami ratunkowymi oraz furto-rampy rufowej. Zastosowana tu furto-rampa z elementem wypornościowym umożliwia zwiększenie jej funkcji do samoczynnego dostosowania kąta jej wychylenia roboczego w przypadku znacznego przegłębienia statku na dziób. Przedstawiony układ hydrauliczny...
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CAUSALITY IN MODELS OF THERMAL PROCESSES IN SHIP ENGINE ROOMS WITH THE USE OF BOND GRAPH (BG) METHOD
PublicationWith a single approach to modeling elements of different physical nature, the method of Bond Graph (BG) is particularly well suited for modeling energy systems consisting of mechanical, thermal, electrical and hydraulic elements that operate in the power system engine room. The paper refers to the earlier presented new concept of thermal process modeling using the BG method. The authors own suggestions for determining causality...
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The system combined of low-speed marine diesel engine and steam turbine in ship propulsion applications
PublicationPrzedstawiono koncepcje okrętowego układu kombinowanego silnik wolnoobrotowy tłokowy- turbina parowa, wykorzystującego ciepło zawarte w spalinach wylotowych.Porównano układ kombinowany dużej mocy dla dwóch silników tłokowych porównywalnych mocy z punktu widzenia termodynamicznego.
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Variations of Ship’s Deck Elevation Due to Stochastic Process of Containers Loading
PublicationThe stochastic process of container loading is described in the paper with special emphasis to ship motion when she is lying at a quay. The 3 DOF system was applied to describe rolling, pitching and heaving of a vessel which may cause a significant variations of momentary deck elevation. The realistic range of such variations are assessed for a variety of cargo locations on-board and a phase shift between two independent gantries...
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SPECTRAL-BASED MODAL PARAMETERS IDENTIFICATION WITH MULTIPLE PARTICLE SWARMS OPTIMIZATION
PublicationThe paper presents usage of a Particle Swarm Optimization [1] based algorithm for spectral-based modal parameters identification. The main algorithm consists of two groups of swarms, namely, scouts and helpers. For the first group additional penalizing process is provided to force separation of scouting swarms in frequency space. The swarms have an ability to communicate with each other. At first stage, each swarm focuses on a...
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Modelling and analysis of medium frequency transformers for power converters
PublicationThe evolutions in power systems and electric vehicles, related to the economic opportunities and the environmental issues, bring the need of high power galvanically isolated DC-DC converter. The medium frequency transformer (MFT) is one of its key components, enabled by the increasing switching frequency of modern power semiconductors like silicon carbide transistors or diodes. The increased operating frequency offers small...
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RANS-based design optimization of dual-rotor wind turbines
PublicationPurpose An improvement in the energy efficiency of wind turbines can be achieved using dual rotors. Because of complex flow physics, the design of dual-rotor wind turbines (DRWTs) requires repetitive evaluations of computationally expensive partial differential equation (PDE) simulation models. Approaches for solving design optimization of DRWTs constrained by PDE simulations are investigated. The purpose of this study is to determine...
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Inverse Modeling and Optimization of CSRR-based Microwave Sensors for Industrial Applications
PublicationDesign optimization of multivariable resonators is a challenging topic in the area of microwave sensors for industrial applications. This paper proposes a novel methodology for rapid re-design and parameter tuning of complementary split-ring resonators (CSRRs). Our approach involves inverse surrogate models established using pre-optimized resonator data as well as analytical correction techniques to enable rapid adjustment of geometry...
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Lexicographic and weighting approach to multi-criteria portfolio optimization by mixed integer programming
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Resilience through multicast – An optimization model for multi-hop wireless sensor networks
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Data on bicycle traffic in Lodz (Poland) paired with weather and air quality data
Open Research DataThe file contains data on bicycle traffic registered by counting stations loacted in Lodz in the years 2016-2019. The data are paired with weather and air quality data from Lodz collected for the same period. The data is described below:
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Ultra-Compact Self-Quadruplexing Microfluidically Frequency Reconfigurable Slot Antenna Using Half-Mode SIW
PublicationIn this brief, the design of an ultra-compact self-quadruplexing frequency reconfigurable antenna (SQFRA) utilizing a half-mode substrate-integrated waveguide (HMSIW) and microfluidic channels is discussed. Four HMSIW cavities fed by four microstrip lines and slots are used to construct a highly compact antenna. The microstrip feedings to the HMSIW cavities are applied in such a way that the proposed antenna exhibits self-quadruplexing...
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Improving evolutionary multi-objective optimisation using genders [Usprawnienie ewolucyjnej wielokryterialnej optymalizacji poprzez zastosowanie rodzajników]
PublicationW rozwiązywaniu wielkowymiarowych problemów wielokryterialnej optymalizacji za pomocą obliczeń ewolucyjnych (EMO) koncepcja dominacji w sensie Pareto nie jest efektywna. Dlatego w pracy rozważa się nowe podejście do rozwiązywania zadań wielokryterialnej optymalizacji metodą EMO, w którym wprowadza się pojęcie rodzajników genetycznych w celu rozróżnienia rozmaitych grup kryteriów oraz związanych z nimi subkryterialnych rozwiązań...
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Computer-aided analysis of resonance risk in power system with Static Var Compensators
PublicationStatic Var Compensators operation in a power system may significantly improve voltage profiles in nodes and the reactive power balance, as well as ensure greater system stability in emergency conditions. However these devices may be a cause of a resonance in the system. The aim of this paper is to call attention to the need to include resonance phenomena in a compensator’s location evaluation process. The analysis performed in...
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Productivity effects of trade in natural resources—comparison with mechanisms of technological specialisation
PublicationThis paper compares two alternative growth paths, assessing the effects on productivity of specialisation in natural resources (NR) and in technologically advanced products. The empirical analysis exploits product-level export data for 109 developing and 51 developed economies over the period 1996–2018. We document two distinct types of specialisation, based on exports either of natural resources or of technological products, and...
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Parametric optimization of sandwich composite footbridge with U-shaped cross-section
PublicationParametric optimization of sandwich composite footbridge was presented in the paper. Composite footbridge has 14,5 m long and has U-shaped cross-section with inner dimensions 2,6 × 1,3 m. The sandwich structure in made from GFRP laminate as a faces and PET foam as a core. The aim of analysis was to minimize the mass of the new footbridge that can lead to minimize the cost of structure. After optimization was conducted, the new...
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Polyarmonic model of synchronous generator for analysis of autonomous power generation systems
PublicationAbstract: This paper presents the polyharmonic modelling of synchronous generator (SG) in machine variables. The simple geometry and windings physical layout has been used for inductance calculations of a salient-pole SG. The main advantage of this model is the ease of describing an autonomous power generation system (APGS) in terms of its topology and thus providing effective analysis at the static and dynamic states, both for...
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Complex multidisciplinary optimization of turbine blading systems
PublicationThe paper describes the methods and results of direct optimization of turbine blading systems using a software package Opti_turb. The final shape of the blading is obtained from minimizing the objective function, which is the total energy loss of the stage, including the leaving energy. The current values of the objective function are found from 3D RANS computations (from a code FlowER) of geometries changed during the process...
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Routing Method for Interplanetary Satellite Communication in IoT Networks Based on IPv6
PublicationThe matter of interplanetary network (IPN) connection is a complex and sophisticated topic. Space missions are aimed inter alia at studying the outer planets of our solar system. Data transmission itself, as well as receiving data from satellites located on the borders of the solar system, was only possible thanks to the use of powerful deep space network (DSN) receivers, located in various places on the surface of the Earth. In...
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Are Pair Trading Strategies Profitable During COVID-19 Period?
PublicationPair trading strategy is a well-known profitable strategy in stock, forex, and commodity markets. As most of the world stock markets declined during COVID-19 period, therefore this study is going to observe whether this strategy is still profitable after COVID-19 pandemic. One of the powerful algorithms of DBSCAN under the umbrella of unsupervised machine learning is applied and three clusters were formed by using market and accounting...
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Influence of Shunt Compensation with SVC Devices on Resonance Risk in Power Systems
PublicationMany analyses are required to locate a new reactive power source in a power system. The choice of a location is a very complex matter which requires various aspects to be considered. Selecting a location also entails the necessity to assess it from the point of view of the selected compensator’s structure as well as the system’s performance in various states with the new device on. The paper presents the issues of assessing compensator...
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Optimization of Train Energy Cooperation Using Scheduled Service Time Reserve
PublicationThe main aim of the paper was to develop an innovative approach to the preliminary estimation possibility of train energy cooperation based on data from timetables, without traction calculations. The article points out the need to strive for sustainable and environmentally friendly transport. It was pointed out that rail transport using electric traction is one of the more ecological branches of transport. It also offers a number...
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Ryszard Woźniak dr inż.
PeopleRyszard Woźniak received his M.Sc. (1984) from the Lublin University of Technology specializing in Cars and Tractors. In 2002, at the Gdansk University of Technology he defended his doctoral thesis on: "Tyre/road noise when large longitudinal forces are applied in tyre/road contact patch" and obtained a doctorate degree in technical sciences in the field of construction and operation of machines. Currently he is an adjunct at the...
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Investigations on strength and fracture in RC beams scaled along height or length
PublicationThe objective of the present paper is to identify experimentally and theoretically differing failure mechanisms in reinforced concrete beams subjected to four-point bending for a separate variation of the depth and length at the constant thickness. Experiments were performed on reinforced concrete beams under four-point bending. Different failure mechanisms included steel yielding, diagonal tension or shear- compression depending...
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Analysis of Lombard speech using parameterization and the objective quality indicators in noise conditions
PublicationThe aim of the work is to analyze Lombard speech effect in recordings and then modify the speech signal in order to obtain an increase in the improvement of objective speech quality indicators after mixing the useful signal with noise or with an interfering signal. The modifications made to the signal are based on the characteristics of the Lombard speech, and in particular on the effect of increasing the fundamental frequency...
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Extreme weather layer method for implementation of nature-based solutions for climate adaptation: Case study Słupsk
PublicationOne of the most severe climate risks that is expected to affect all regions is related to stormwater. Climate models, constructed based on long-term trends, show that extreme weather events such as storms, cloudbursts and a large rise in sea level will be significant in the coming decades. Moreover, even the frequency and intensity of “normal” rainfall events, such as microbursts, are expected to be remarkably higher than today...
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Low-Cost and Highly-Accurate Behavioral Modeling of Antenna Structures by Means of Knowledge-Based Domain-Constrained Deep Learning Surrogates
PublicationThe awareness and practical benefits of behavioral modeling methods have been steadily growing in the antenna engineering community over the last decade or so. Undoubtedly, the most important advantage thereof is a possibility of a dramatic reduction of computational expenses associated with computer-aided design procedures, especially those relying on full-wave electromagnetic (EM) simulations. In particular, the employment of...
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Towards solving heterogeneous fleet vehicle routing problem with time windows and additional constraints: real use case study
PublicationIn advanced logistic systems, there is a need for a comprehensive optimization of the transport of goods, which would reduce costs. During past decades, several theoretical and practical approaches to solve vehicle routing problems (VRP) were proposed. The problem of optimal fleet management is often transformed to discrete optimization problem that relies on determining the most economical transport routes for a number of vehicles...
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Generic appearance of objective results in quantum measurements
PublicationMeasurement is of central interest in quantum mechanics as it provides the link between the quantum world and the world of everyday experience. One of the features of everyday experience is its robust, objective character, contrasting the delicate nature of quantum systems. Here we analyze in a completely model-independent way the celebrated von Neumann measurement process, using recent techniques of information flow, studied in...
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ASSESSMENT OF NATURAL VENTILATION SYSTEM FOR A TYPICAL RESIDENTIAL HOUSE IN POLAND
PublicationThe paper presents the research results of field measurements campaign of natural ventilation performance and effectiveness in a residential building. The building is located in the microclimate whose parameters differ significantly in relation to a representative weather station. The measurement system recorded climate parameters and the physical variables characterizing the air flow in the rooms within 14 days of the winter season....
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Ultra-thin film of aluminum oxide influence on the plasmon resonance in gold nanostructures
Open Research DataUltra-thin film of aluminum oxide influence on the plasmon resonance in gold nanostructures was measured by UV-VIS spectroscopy. Ultra thin film of Al2O3 was deposited on a gold nanostructures. Thickness of film was 2nm - 8nm. Shift of plasmon resonance was observed, as a result of various dielectric constant of layer.
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The time-varying low-frequency magnetic-field emitted from the ship’s inverter-fed induction motor
Open Research DataThe dataset contains the magnetic field measurement results that are part of a comprehensive study on the assessment of the magnetic field emissions onboard of the research-training vessel. The measurements were carried out, nearby the bow thruster motor fed from the inverter, during maneuvering and the sea voyage. The bow thruster is assembled in the...
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Optimization-based antenna miniaturization using adaptively-adjusted penalty factors
PublicationThe continuing trend for miniaturization of electronic devices necessitates size reduction of the comprising components and circuitry. Specifically, integrated circuit-antenna modules therein require compact radiators in applications such as 5G communications, implantable and on-body devices, or internet of things (IoT). The conflict between the demands for compact size and elec-trical and field performance can be mitigated by...
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Monotone iterative method for first-order differential equations at resonance
PublicationThis paper concerns the application of the monotone iterative technique for first-order differential equations involving Stieltjes integrals conditions. We discuss such problems at resonance when the measure in the Stieltjes integral is positive and also when this measure changes the sign. Sufficient conditions which guarantee the existence of extremal, unique and quasi-solutions are given. Three examples illustrate the results.
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Toward Fast Calculation of Communication Paths for Resilient Routing
PublicationUtilization of alternate communication paths is a common technique to provide protection of transmission against failures of network nodes/links. However, a noticeable delay is encountered when calculating the relevant sets of disjoint paths using the available algorithms (e.g., using Bhandari’s approach). This, in turn, may have a serious impact on the ability of a network to serve dynamic demands...
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Natural convection in symmetrically heated vertical channels
PublicationThe study describes natural convection through a vertical channel, open on four sides and bound by two isothermal walls. Both balancing and infrared experimental investigations were performed in air (Pr = 0.71) to estimate the impact of channel width s and wall-to-ambient temperature difference (tw - t∞) on natural convective heat transfer, the formation of air flow patterns and the rate of flow pattern formation. The study was...
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A Study of the Roll Motion by Means of a Free Decay Test
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Study of Slip Effects in Reverse Roll Coating Process Using Non-Isothermal Couple Stress Fluid
PublicationThe non-isothermal couple stress fluid inside a reverse roll coating geometry is considered. The slip condition is considered at the surfaces of the rolls. To develop the flow equations, the mathematical modelling is performed using conservation of momentum, mass, and energy. The LAT (lubrication approximation theory) is employed to simplify the equations. The closed form solution for velocity, temperature, and pressure gradient...
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Gossiping by energy-constrained mobile agents in tree networks
PublicationEvery node of an edge-weighted tree network contains a data packet. At some nodes are placed mobile agents, each one possessing an amount of energy (not necessarily the same for all agents). While walking along the network, the agents spend the energy proportionally to the distance traveled and collect copies of the data packets present at the visited network nodes. An agent visiting a node deposits there copies of all currently...
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Raman spectra for pyrolized natural compounds
Open Research DataThe presented data showcases the results of Raman spectroscopy analysis conducted on pyrolyzed natural compounds both with and without the inclusion of graphene. The study delved into four specific compounds: methylcellulose with lysine (ML), methylcellulose with lysine-graphene composite (MLG), algae (A), and algae-graphene composite (AG). Raman spectra...