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Wyniki wyszukiwania dla: initial value problem
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Geo-engineering computer simulation seems attractive but is it the real world?
PublikacjaCorrect formulation of the differential equation system for equilibriom conditions of subsoil, especially in terms of controlled numerical calculation, is discussed. The problem of solution stability is also considered. The solution of problems, which are ill-posed, have no practical value in the majority of cases and is this way the engineering prognosis can lead to real disaster. The object of this paper is quite relevant if...
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Effect of soil moisture on current-carrying capacity of low-voltage power cables
PublikacjaOne of the factors affecting current-carrying capacity of underground power cables is the thermal resistivity of soil. Its value in the close proximity of the cable is the most important, and for this reason, in some cases, the local soil is replaced with an another soil type or with a cement-sand mixture. The thermal resistivity of the soil is strongly affected by moisture, and in the case of a cement-sand mixture – as tested...
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The Suzuki model of the multipath fading channel
Dane BadawczeThe dataset contains the results of simulations that are part of the research on modelling the multipath fading in the communication channel. The Suzuki fading envelope is generated using the Monte-Carlo simulation (MCS) in the LabVIEW programming environment.
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Experimental study on the behaviour of steel columns under seismic-induced axial impact load
PublikacjaIt has been observed during major earthquakes that the so called soft-storey failure of an upper floor of a structure results in large impact load acting on structural members of the lower storeys. It may further lead to progressive collapse of the whole structure substantially intensifying human and material losses. Therefore, the aim of this paper is to investigate experimentally the behaviour of columns under bending (observed...
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Synthesis, thermal, structural and electrical properties of vanadium-doped lithium-manganese-borate glass and nanocomposites
PublikacjaA glassy sample with a nominal formula LiMn1−3x/2VxBO3 (where x = 0.05) was synthesised using the melt-quenching method. Material was characterised by differential thermal analysis (DTA), X-ray diffactometry (XRD) at room temperature and as a function of temperature (HT-XRD), X-ray photoelectron spectroscopy (XPS), impedance spectroscopy (IS) and scanning electron microscopy (SEM). Dependences of glass transition and crystallisation...
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Ocena efektywności monitoringu obiektów inżynierskich za pomocą sieci Bayesa
PublikacjaW swojej pracy autorzy zaproponowali zastosowanie sieci Bayesa do projektowania monitoringu i podejmowania decyzji w działaniach eksploatacyjnych. Ponadto pokazano dwie metody oceny wartości informacji diagnostycznych. Pierwszą z nich jest wartość oczekiwana EVSI (ang. Expected Value of Sample Information), która stanowi podstawę do wyboru spośród alternatywnych obserwacji symptomów zmiennej diagnostycznej. Natomiast drugą metodą...
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Methods of determination of C coefficient for period of rolling vessel in calm water for example of pax cargo ship
PublikacjaThis article presents a different approach to calculate the C coefficient needed to determine the period of own rolling vessel in calm water. The C coefficient is usually adopted as the approximate value from the available literature, usually depending on the type of vessel, and less dependent on the loading condition. In experimental studies of marine properties (seakeeping) often have a problem with the selection of the correct...
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Problemy z powłokami antykorozyjnymi na elementach wyposażenia obiektów mostowych
PublikacjaPrzedstawiono problem wadliwości zabezpieczenia antykorozyjnego w zakresie malarskich powłok ochronno - dekoracyjnych wykonywanych na stalowych elementach barier zabezpieczonych uprzednio poprzez ocynkowanie metodą zanurzeniową. Wykorzystując przykłady pochodzące z różnych obiektów przedstawiono powtarzający się problem delaminacji powłok malarskich, niezależny od rodzaju zastosowanych wyrobów lakierniczych oraz znacznego rozwoju...
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Ultrashort Opposite Directed Pulses Dynamics with Kerr Effect and Polarization Account
PublikacjaWe present the application of projection operator methods to solving the problem of the propagation and interaction of short optical pulses of different polarizations and directions in a nonlinear dispersive medium. We restrict ourselves by the caseof one-dimensional theory, taking into account material dispersion and Kerr nonlinearity. The construction of operators is delivered in two variants: for the Cauchy problem and for the...
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Clearing directed subgraphs by mobile agents
PublikacjaWe study several problems of clearing subgraphs by mobile agents in digraphs. The agents can move only along directed walks of a digraph and, depending on the variant, their initial positions may be pre-specified. In general, for a given subset S of vertices of a digraph D and a positive integer k, the objective is to determine whether there is a subgraph H=(V,A) of D such that (a) S is a subset of V, (b) H is the union of k directed...
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Problemy z powłokami antykorozyjnymi na elementach wyposażenia obiektów mostowych
PublikacjaOpisano problem wadliwości zabezpieczenia antykorozyjnego w zakresie malarskich powłok ochronno-dekoracyjnych wykonywanych na stalowych elementach barier zabezpieczonych uprzednio poprzez ocynkowanie metodą zanurzeniową na gorąco. Wykorzystując przykłady pochodzące z różnych obiektów przedstawiono powtarzający się problem delaminacji powłok malarskich, niezależny od rodzaju zastosowanych wyrobów lakierniczych oraz znacznego rozwoju...
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Elementary analysis and energetic potential of the municipal sewage sludges from the Gdańsk and Kościerzyna WWTPs
PublikacjaThis paper aims to present municipal sewage sludge (MSS) elementary analysis and energetic potential based on measurement of heat of combustion (higher heating value HHV) and calculation of calorific values (lower heating value LHV). The analysis takes into the consideration water content in sewage sludge, at different utilization stages, in wastewater treatment plants in Gdańsk Wschód and Kościerzyna – Pomeranian Voivodeship....
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Extracellular proteolytic activity of Deinococcus geothermalis
PublikacjaProduction of extracellular protease by extremophilic bacteria Deinococcus geothermalis cultivated in liquid media containing 0.1% (w/v) of peptone K, 0.1% yeast extract and 0.2% marine salt reached a maximum in 14 h of the cell growth at 45°C and pH 8.0. The enzyme was purified by a two-step procedure using fractionation by a graded ammonium sulphate precipitation technique and gel filtration on Sephadex G-100 column. Protease...
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Positive solutions to Sturm–Liouville problems with non-local boundary conditions
PublikacjaIn this paper, the existence of at least three non-negative solutions to non-local boundary-value problems for second-order differential equations with deviating arguments α and ζ is investigated. Sufficient conditions, which guarantee the existence of positive solutions, are obtained using the Avery–Peterson theorem. We discuss our problem for both advanced and delayed arguments. An example is added to illustrate the results.
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Simultaneous Removal of Al, Cu and Zn Ions from Aqueous Solutions Using Ion and Precipitate Flotation Methods
PublikacjaThis paper presents the results of investigations concerning the simultaneous removal of Al(III), Cu(II), and Zn(II) from dilute aqueous solutions using ion and precipitate flotation methods. The effects of initial solution pH, surface active substance concentration, and the gas velocity on the flotations’ efficiency and course are studied. Experimental results are discussed in terms of physicochemical aspects related to aqueous...
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Krystyna Nagrodzka-Godycka prof. dr hab. inż.
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Disaster-Resilient Routing Schemes for Regional Failures
PublikacjaLarge-scale natural disasters can have a profound effect on the telecommunication services in the affected geographical area. Hence, it is important to develop routing approaches that may help in circumventing damaged regional areas of a network. This prompted the development of geographically diverse routing schemes and also of disaster-risk aware routing schemes. A minimum-cost geodiverse routing, where a minimum geographical...
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Scheduling jobs to contain a natural disaster: a model and complexity
Publikacjathis paper is devoted to the problem of scheduling suppression units so that a natural disaster is dealt with as efficient as possible. the concept of deteriorating jobs is adopted, that is, the formal model of scheduling represents linearly increasing value loss as the disaster remains unsuppressed and increasing time for its suppression. more precisely, two different goals are considered: finding a suppression schedule of minimal...
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Interval incidence graph coloring
PublikacjaIn this paper we introduce a concept of interval incidence coloring of graphs and survey its general properties including lower and upper bounds on the number of colors. Our main focus is to determine the exact value of the interval incidence coloring number χii for selected classes of graphs, i.e. paths, cycles, stars, wheels, fans, necklaces, complete graphs and complete k-partite graphs. We also study the complexity of the...
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Problems and Solutions of Software Design in Scrum Projects
PublikacjaThe aim of the paper is to identify the problems and solutions of the software design in Scrum project as well as to analyze the effectiveness of the solutions. Through a series of workshops with 4 experts from IT industry and academia we have identified 52 problems and 99 unique solutions. In this paper we present a list of 10 common problems and 5 solutions for each problem selected by the number of sources. The effectiveness...
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Fast and reliable knowledge-based design closure of antennas by means of iterative prediction-correction scheme
PublikacjaA novel framework for expedited antenna optimization with an iterative prediction-correction scheme is proposed. The methodology is comprehensively validated using three real-world antenna structures: narrow-band, dual-band and wideband, optimized under various design scenarios. The keystone of the proposed approach is to reuse designs pre-optimized for various sets of performance specifications and to encode them into metamodels...
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Basic sensitivity analysis of a telecommunication tower complementing standard reinforcement design process
PublikacjaThis paper presents straightforward sensitivity assessment of a telecommunication tower. The analysis is set toidentify the elements of the tower which may be reinforced with the greatest structural advantage. As current expertopin ions on structural redesign of similar structures due to a planned addition of extra loads are mainly based ondeterministic computations or engineering intuition,...
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Seaweed as a resource for Anaerobic Digestion
PublikacjaExtensive growth of algae contributes to disruptive changes to the water ecosystems. This is mainly caused by redundant nutrients that are washed off the land and end up in waters. Tackling eutrophication by recovery of nutrients can be a solution to the problem. Cast marine biomass can be a resource for renewable energy technologies like anaerobic digestion. Such approach can contribute to the transition to a circular bio-economy and...
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Modal modification of structural damping applied to increase the stability and convergence of numerical integration
PublikacjaThe presented paper refers to numerical tests done on systems fused of multibody and finite-element parts. The appearance of its multibody part gives rise to significant nonlinear components, i.e., second-order nonlinear differential equations express the dynamics. We usually solve these equations by “step-by-step” integration methods. When using the currently available integration algorithms, we approximate these initial systems...
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Wodór jako paliwo cz. 2
PublikacjaW artykule scharakteryzowano aktualne i przyszłościowe metody wytwarzania wodoru. Przedstawiono problem związany z przechowywaniem wodoru oraz ukazano aktualne i przyszłościowe rozwiązania dotyczące magazynowania wodoru.
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Collaborative Delivery by Energy-Sharing Low-Power Mobile Robots
PublikacjaWe study two variants of delivery problems for mobile robots sharing energy. Each mobile robot can store at any given moment at most two units of energy, and whenever two robots are at the same location, they can transfer energy between each other, respecting the maximum capacity. The robots operate in a simple graph and initially each robot has two units of energy. A single edge traversal by an robot reduces its energy by one...
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3D intact knee model used in analysis of the medial meniscus biomechanics in the osteoarthritic knee joint - input text file for computation
Dane BadawczeThe finite element method was used to simulate the stance phase of the gait cycle. An intact knee model with original geometry and material parametetrs was prepared based on magnetic resonance scans of the left knee joint of a healthy volunteer. The file was created in Abaqus 6.14-2, but can be read in a text editor.
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The Gini index in Poland in 2008-2017
Dane BadawczeWhen assessing the level of poverty, one should use indicators presenting indicators of social inequality in terms of income, indicators of prosperity and poverty In Poland, the situation in terms of inequality is improving, but as measured by the Gini coefficient. The coefficient, which ranges from zero to one hundred percent, the higher it is, the...
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Parametric method for evaluating optimal ship deadweight
PublikacjaThe paper presents a method of choosing the optimal value of the cargo ships deadweight. The method may be useful at the stage of establishing the main owners requirements concerning the ship design parameters as well as for choosing a proper ship for a given transportation task. The deadweight is determined on the basis of a selected economic measure of the transport effectiveness of ship – the Required Freight Rate (RFR). The...
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Experimental ultimate strength assessment of stiffened plates subjected to marine immersed corrosion
PublikacjaThis study experimentally analyses the impact of marine immersed corrosion degradation on the compressive strength of the stiffened plates where the lower degradation levels were considered. The corrosion degradation test was accelerated by controlling the natural corrosion environmental factors, avoiding applying an electric current. Different groups of corrosion degradation levels and initial plate thicknesses were investigated....
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Voltage Dependence of Supercapacitor Capacitance
PublikacjaElectronic Double-Layer Capacitors (EDLC), called Supercapacitors (SC), are electronic devices that are capable to store a relatively high amount of energy in a small volume comparing to other types of capacitors. They are composed of an activated carbon layer and electrolyte solution. The charge is stored on electrodes, forming the Helmholtz layer, and in electrolyte. The capacitance of supercapacitor is voltage- dependent. We...
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Positive solutions for second order impulsive differential equations involving Stieltjes integral conditions
PublikacjaIn this paper we investigate integral boundary value problems for fourth order differentialequations with deviating arguments.Wediscuss our problem both for advanced or delayedarguments. We establish sufficient conditions under which such problems have positivesolutions. To obtain the existence of multiple (at least three) positive solutions, we use afixed point theorem due to Avery and Peterson. An example is also included to...
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First-order differential equations with nonlocal boundary conditions
PublikacjaWe study a first-order boundary value problem subject to some boundary conditions given by Riemann-Stieltjes integrals. Using a monotone iterative method, we formulate sufficient conditions which guarantee the existence of extremal or quasi-solutions in the corresponding region bounded by upper and lower solutions of our problems. The case when a unique solution exists is also investigated. Some examples are given to illustrate...
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Cavity-expansion approximation for projectile impact and penetration into sand
PublikacjaA one-dimensional problem of a spherical cavity expanding at a constant velocity from zero initial radius in an infinite granular medium, which has the first-kind self-similar solution, is considered. We are solving this dynamic spherical cavity-expansion problem to model rigid spheres penetrating into a granular media. Elastic–plastic deformation of the granular media is described in a barotropic approximation, using the high-pressure...
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Schemat powstawania rys na przykładzie osiowo rozciąganego pręta żelbetowego
PublikacjaW artykule przedstawiono w sposób schematyczny ideę powstawania kolejnych rys w konstrukcjach żelbetowych na przykładzie osiowo rozciąganego pręta. Opisano początkowy oraz końcowy stan zarysowania. Wyprowadzono wzór na szerokość rysy. Przedstawiono interpretację geometryczną rys dla fazy początkowego zarysowania oraz efekt tension stiffening na przykładzie elementu osiowo rozciąganego. Przedstawiono przykładowe obliczenia miary...
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The voltage on bus bars of the main switchboard of the ferry electrical power system during maneuvering
Dane BadawczeThe dataset is part of the research results on the quality of supply voltage on bus bars of the main switchboard of the ship's electrical power system in different states of ship exploitation. The attached dataset contains the measurement results carried out onboard the ferry during maneuvering.
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Fragmentation of Hydrographic Big Data Into Subsets During Reduction Process
PublikacjaThe article presented problems of fragmentation of hydrographic big data into smaller subsets during reduction process. Data reduction is a processing of reduce the value of the data set, in order to make them easier and more effective for the goals of the analysis. The main aim of authors is to create new reduction method. The article presented the first stage of this method – fragmentation of bathymetric data into subsets. It...
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3D model of osteoarthritic (OA) knee joint for analysis of the medial meniscus biomechanics - input text file for computation
Dane BadawczeThe finite element method was used to simulate the stance phase of the gait cycle. An intact knee model was prepared based on magnetic resonance scans of the left knee joint of a healthy volunteer. In the OA model thickness of articular cartilage and material parameters of the cartilage and menisci were reduced to simulate degenerative changes in the...
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3D knee model G with reduced thickness of articular cartilage - input text file for computation
Dane BadawczeThe finite element method was used to simulate the stance phase of the gait cycle. An intact knee model was prepared based on magnetic resonance scans of the left knee joint of a healthy volunteer. In the model G articular cartilage thickness was reduced in specific areas to simulate degenerative changes in the medial knee osteoarthritis. The file was...
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3D knee model M with decreased material parameters of the cartilage and menisci - input text file for computation
Dane BadawczeThe finite element method was used to simulate the stance phase of the gait cycle. An intact knee model was prepared based on magnetic resonance scans of the left knee joint of a healthy volunteer. In the model M the material parameters of cartilage and menisci were reduced to simulate degenerative changes in the medial knee osteoarthritis. The file...
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The surface of the sensor used in the analysis of odorous substances
Dane BadawczeHuman industrial activity usually leads to smaller or larger interference with the ecosystem, contributing to changes affecting the quality of life. An example may be the emission of gaseous substances, not necessarily toxic, but due to their intense smell, they can cause discomfort to people exposed to their inhalation. The problem is so important...
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Minimal number of periodic points with the periods less or equal to r in the smooth homotopy class of simply-connected manifolds of dimension 4 and homology groups with the sum of ranks less or equal to10
Dane BadawczeAn important problem in periodic point theory is minimization of the number of periodic points with periods <= r in a given class of self-maps of a space. A closed smooth and simply-connected manifolds of dimension 4 and its self-maps f with periodic sequence of Lefschetz numbers are considered. The topological invariant Jr[f] is equal to the minimal...
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Minimal number of periodic points with the periods less or equal to r in the smooth homotopy class of simply-connected manifolds of dimension 6 and homology groups with the sum of ranks less or equal to10
Dane BadawczeAn important problem in periodic point theory is minimization of the number of periodic points with periods <= r in a given class of self-maps of a space. A closed smooth and simply-connected manifolds of dimension 6 and its self-maps f with periodic sequence of Lefschetz numbers are considered. The topological invariant Jr[f] is equal to the minimal...
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Minimal number of periodic points with the periods less or equal to r in the smooth homotopy class of simply-connected manifolds of dimension 5 and homology groups with the sum of ranks less or equal to10
Dane BadawczeAn important problem in periodic point theory is minimization of the number of periodic points with periods <= r in a given class of self-maps of a space. A closed smooth and simply-connected manifolds of dimension 5 and its self-maps f with periodic sequence of Lefschetz numbers are considered. The topological invariant Jr[f] is equal to the minimal...
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Minimal number of periodic points with the periods less or equal to r in the smooth homotopy class of simply-connected manifolds of dimension 8 and homology groups with the sum of ranks less or equal to 10
Dane BadawczeAn important problem in periodic point theory is minimization of the number of periodic points with periods <= r in a given class of self-maps of a space. A closed smooth and simply-connected manifolds of dimension 8 and its self-maps f with periodic sequence of Lefschetz numbers are considered. The topological invariant Jr[f] is equal to the minimal...
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Minimal number of periodic points with the periods less or equal to r in the smooth homotopy class of simply-connected manifolds of dimension 7 and homology groups with the sum of ranks less or equal to10
Dane BadawczeAn important problem in periodic point theory is minimization of the number of periodic points with periods <= r in a given class of self-maps of a space. A closed smooth and simply-connected manifolds of dimension 7 and its self-maps f with periodic sequence of Lefschetz numbers are considered. The topological invariant Jr[f] is equal to the minimal...
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System identification
Kursy OnlineThe course focusses on the problem of identification of dynamic systems.
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System identification - new
Kursy OnlineThe course focusses on the problem of identification of dynamic systems.
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Collision-Free Network Exploration
PublikacjaA set of mobile agents is placed at different nodes of a n-node network. The agents synchronously move along the network edges in a collision-free way, i.e., in no round may two agents occupy the same node. In each round, an agent may choose to stay at its currently occupied node or to move to one of its neighbors. An agent has no knowledge of the number and initial positions of other agents. We are looking for the shortest possible...
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Corncob-supported calcium oxide nanoparticles from hen eggshells for cadmium (Cd-II) removal from aqueous solutions; Synthesis and characterization
PublikacjaThis study investigated the efficient removal of cadmium ions from aqueous solutions using calcium oxide nanoparticles (CaO NPs) synthesized from waste hen eggshells using a Sol-gel method and supported on corncob bio-adsorbent. The synthesized CaO NPs were characterized using FT-IR, XRD, specific surface area, and TGA. Batch adsorption experiments were conducted to examine the influence of process parameters such as adsorbent...