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Search results for: MECHANICAL STRESSES IN ENCLOSURES
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An Innovative Floating System with a Savonius Rotor as a Horizontal-Axis Wind Turbine
PublicationIn this project, an innovative wind turbine was designed for a floating plant. A large Savonius rotor was replaced with a double-rotor wind turbine implemented as a horizontal-axis turbine. This double rotor was positioned on the tip of a thrust plate and fixed to the deck of a catamaran. Simple 2D numerical simulations were performed to confirm the effectiveness of the concept. An analysis of the floating system configuration...
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Effect of bitumen characteristics obtained according to EN and Superpave specifications on asphalt mixture performance in low-temperature laboratory tests
PublicationThe paper aims to identify those characteristics of bitumen which have the greatest impact on asphalt mixture low-temperature performance. It was observed that stiffness and m-value of bitumen from BBR test were moderately related to stiffness and m-value of asphalt mixture obtained from 3 PB test. Simultaneously those rheological properties significantly impact on cryogenic stresses induced during TSRST test. The multiple regression...
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On weak solutions of boundary value problems within the surface elasticity of Nth order
PublicationA study of existence and uniqueness of weak solutions to boundary value problems describing an elastic body with weakly nonlocal surface elasticity is presented. The chosen model incorporates the surface strain energy as a quadratic function of the surface strain tensor and the surface deformation gradients up to Nth order. The virtual work principle, extended for higher‐order strain gradient media, serves as a basis for defining...
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Acoustic aspects of synthetic jet – review
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Synthetic jet actuator with two opposite diaphragms
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Simulation of fluid structure interaction in a novel design of high pressure axial piston hydraulic pump
PublicationA novel type of an axial, piston-driven high pressure hydraulic pump with variable capacity marks a significant improvement in the area of the hydraulic machinery design. Total discharge from hydrostatic forces eliminates a need for a servomechanism, thus simplifying operation, reducing weight and introducing the possibility of the pump displacement control by computer. PWK-type pumps, invented in the Gdansk University of Technology,...
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Doświadczalne badania wytrzymałości zmęczeniowej stopów łożyskowych
PublicationW pracy przedstawiono wyniki badań nad wytrzymałością zmęczeniową warstw ślizgowych wykonanych z wybranych materiałów stosowanych w cienkościennych panwiach łożyskowych współczesnych maszyn. Badania przeprowadzono za pomocą urządzeń badawczych skonstruowanych i zbudowanych w Politechnice Gdańskiej. Przedstawiono zaobserwowane pęknięcia zmęczeniowe badanych próbek oraz oszacowano odpowiadające im krytyczne wartości naprężeń w warstwach...
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Procedura kontrolowanego wywrócenia żurawia stoczniowego
PublicationPrzedstawiono procedurę złomowania żurawia stoczniowego, wyposażeniowego. Procedurę tę przeprowadzono w przypadku żurawia uszkodzonego w wyniku katastrofy suwnicy bramowej. Może być również stosowana w przypadkach planowego złomowania wielkich dźwignic.
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Design of a microrobotic wrist for needle laparoscopic surgery
PublicationThe paper addresses the design of a micro wrist for needle laparoscopic surgery (needlescopy) using MEMS technology and an original 3 degree of freedom, 3D architecture. Advancement in needlescopy drives the development of multi-dof micro-tools 1-2mmin diameter with 3D mobility but standard available fabricationtechniques are for 2.5D structures. The paper discusses thedevelopment steps and design solutions for the realization...
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Experimental investigations of the hydroelasticity of a liquid-filled tank
PublicationW artykule przedstwiono wyniki badań eksperymentalnych dotyczących współoddziaływania konstrukcji odkształcalnej z cieczą. Badania przeprowadzono na dwóch zbiornikach prostopadłościennych ze sprężyście odkształcalnymi ścianami szczytowymi. Badanie tego zjawiska ma odniesienie do często spotykanych zdarzeń praktycznych jak zderzenie zbiornikowca z innym statkiem lub nabrzeżem portowym.
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Multistage Coupling of Eight Mistuned Bladed Discs on Solid Shaft with 1% Mistuning
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THE PROBLEM OF AIRFLOW AROUND BUILDINGS CLUSTERS IN DIFFERENT CONFIGURATIONS
PublicationIn the paper, the authors discuss the construction of a model of an exemplary urban layout. Numerical simulation has been performed by means of a commercial software Fluent using two different turbulence models: the popular k-ε realizable one, and the Reynolds Stress Model (RSM), which is still being developed. The former is a 2-equations model, while the latter – is a RSM model – that consists of 7 equations. The studies have...
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The Control System Based on FPGA Technology For Fatigue Test Stand MZGS-100 PL
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Dynamic analysis of a satellite with feexible link
PublicationW artykule przedstawiono model przestrzenny satelity złożonego z dowolnej liczby podatnych ramion. Układ taki jest przykładem otwartego łańcucha kinematycznego o strukturze drzewa. Do dyskretyzacji członków podatnych zastosowano modyfikację metody sztywnych elementów skończonych. Równania ruchu wyprowadzono z równań Lagrange'a II rodzaju, stosując do opisu ruchu ciał współrzędne złączowe oraz przekształcenia jednorodne. W symulacjach...
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3D Buckling Analysis of a Truss with Horizontal Braces
PublicationThe present research is devoted to the study of out–of–plane buckling of a truss with horizontal braces. The truss is a model of real roof truss scaled by factor 1=4. A linear buckling and a non–linear analysis with geometric and material non–linearity were carried out. The truss buckling and limit load for different stiffnesses and number of braces are found. Numerical analysis are verified by experiment. Threshold bracing stiffness condition...
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Method of Skeletal System Modelling
PublicationAn original method of skeletal system modelling is presented in detail. Using DICOM images obtained from CT and PET tests, shell models of nine bones were created (humerus, radius, ulna, scapula, clavicle, femur, tibia, fibula, pelvis). Two methods of bone behaviour are also proposed, the first method treating the bone as a solid structure and the second method treating the bone as a complex porous structure. The behaviour of model...
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A Surveillance Of Dynamic Processes in Selected Mechatronic Systems
PublicationThe paper concerns development of original method of optimal control at energy performance index and its application to dynamic processes surveillance of some mechatronic systems. The latter concerns chatter vibration surveillance during highspeed slender milling of rigid details, as well as motion control of two-wheeled mobile platform. Results of on-line computer simulations and real performance on the target objects reflect...
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Experimental Validation of Numerical Model within a Flow Configuration of the Model Kaplan Turbine
PublicationThis paper investigates validation of flow within a model Kaplan turbine. This includes comparison of various turbulence models and their influence on torque and power generated by the turbine. Numerical results were compared with experimental data.
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Buckling Analysis of Cold Formed Silo Column
PublicationThe paper is devoted to stability analysis of different models of steel cold formed silo column. The steel cylindrical silos are often composed of corrugated walls and vertical open-sectional columns uniformly placed along the silo circumference. Both the whole 3D silo, a simplified model consisting of one column with a part of the silo walls, and a single column resting on elastic foundation provided by the silo walls were analyzed....
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Buckling of frame braced by linear elastic springs
PublicationIn the design codes and specifications, simplifed formulae or diagrams are given for determining the buckling lengths of frame columns based on the ruling criterion of considering frames as sway or non sway. Due to the fact that, the code formulae utilize onlylocal stifness distributions, these formulae may yield in certain cases rather erroneous results. In most code formulas a case of weakly braced frames is usually not considered.In...
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HYBRID REDUCED MODEL OF ROTOR
PublicationIn the paper, the authors describe the method of model reduction of a rotor system. The proposed approach enables to obtain a low order model including e.g. nonproportional damping or the gyroscopic effect. This method is illustrated using the example of a rotor system. First, a model of the system was built without gyroscopic and damping effects by using the rigid finite element method. Next, this model was reduced. Finally, two...
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Elastic distortional buckling of thin-walled bars of closed quadratic cross-section
PublicationIn this study a tin-walled bar with closed quadratic cross-section is considered. The elastic stability of axially compressed bar related to the cross-section distortion is investigated. The governing differential equatio is derived with aid of the principle of stationary potential energy. The critical load for simply supported bar is found in an analytical form and it is copared with the FEM solution. Sufficient accuracy of the...
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Simulation of fluid structure interaction in a novel design of high pressure axial piston pump
PublicationA novel type of an axial, piston-driven high pressure hydraulic pump with variable capacity marks a significant improvement in the area of the hydraulic machinery design. Total discharge from hydrostatic forces eliminates a need for a servomechanism, thus simplifying operation, reducing weight and introducing the possibility of the pump displacement control by computer. PWK-type pumps, invented in the Gdansk University of Technology,...
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Professor Jan Kruszewski-Majewski (1929-2012)
PublicationIn this obituary, we present the life and achievements of an outstanding Polish scientist, Professor Jan Kruszewski-Majewski, who passed away in 2012. Professor Jan Kruszewski-Majewski was one of the pioneers in introducing modern numerical methods in mechanics. He created and developed an original, Polish method of modellings called the rigid finite element method. He was ont only an outstanding scientist, but also a person of...
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Forty-five years of the Rigid Finite Element Method
PublicationIn the paper there are described developments of the method in the past 45 year years in dynamical analysis of system with constant and changing in time configuration, including also control of the systems.
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Development of Technical Creativity Featuring Modified TRIZ-AM Inventive Principle to Support Design for Additive Manufacturing
Publicationhe design for additive manufacturing (DFAM) processing was introduced to fully utilise the design freedom provided by additive manufacturing (AM). Consequently, appropriate design methodologies have become essential for this technology. Recently, many studies have identified the importance of DFAM method utilisation to produce AM parts, and TRIZ is a strategy used to formalise design methodologies....
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Method of determining the degree of liquid aeration in a variable capacity displacement pump
PublicationThe Author concludes, that there is a possibility of determining a concrete value of the liquid aeration coefficient during the pump operation by finding such value of coefficient with which the increase of torque of mechanical losses is proportional to the indicated torque determined with a fixed value of increase of pressure in the pump working chambers. The fixed value of increase of pressure assumed in searching the liquid...
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Fish gelatin films containing aqueous extracts from phenolic-rich fruit pomace
PublicationThe aim of the work was to study the feasibility of using aqueous extracts from rowanberry, blue-berried honeysuckle, and chokeberry pomace for the formulation of fish gelatin films with antioxidant and antimicrobial activity as well as improved mechanical and water barrier properties. The predominant phenolic components in rowanberry and chokeberry extracts were hydroxycinnamates, and in blue-berried honeysuckle extract antho cyanins. Although...
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Energy, water detailed usage. Living lab testing for sustainable urban food-water-energy cycle.
Open Research DataData set contains detailed, continuous measurements of the usage of water and electrical energy (AC power) in an experimental facility set up in a scientific laboratory (Laboratorium im. B.Niemkiewicza) at the Faculty of Mechanical Engineering and Ocean Technology of the Gdansk University of Technology. The test bed was established in co-operation...
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A comparative study on selective properties of Kraft lignin–natural rubber composites containing different plasticizers
PublicationEffect of plasticizer type on the kraft lignin–nat- ural rubber composite microstructure and selected proper- ties was determined. The composites were prepared with addition of a commonly used naphthenic oil plasticizer to study the decomposition product of polyurethane (glyc- erolysate) and its characteristics. Kraft lignin powder was incorporated into the natural rubber matrix in amounts of 10 and 40 parts per 100 parts of natural...
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Theoretical examination of the fracture behavior of BC3 polycrystalline nanosheets: Effect of crack size and temperature
Publication2D carbon graphene nanostructures are elements of advanced materials and systems. This theoretical survey provides explanation to the mechanical and fracture behavior of mono- and polycrystalline BC3 nanosheets (denoted as MC- and PCBC3NS, respectively) as a function of temperature and the type of crack defects. The mechanical performance of PCBC3NS at elevated temperatures was monitored varying the number of grain boundaries (the...
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Carboxy derivative of dioxydiphenylpropane diglycydyl ether monomethacrylate as an addtive for composites
PublicationThe modifier of composites was used in the presence of polyetylene polyamine. Physico-mechanical properties and chemical stability of coatings thus obtained were analyzed.
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Nonlocal Models of Plates and Shells with Applications in Micro- and Nanomechanics
PublicationNowadays, the use of small-scale structures in micro/nanomachines has become more and more widespread. The most important applications of such small-sized parts are in micro-electro-mechanical systems (MEMS) as well as nano-electro-mechanical systems (NEMS) as actuators, sensors, energy harvesters. For example, nanosensors are nanoscale devices that measure physical quantities and convert these to signals that can be detected and...
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Controling w zarządzaniu bezpieczeństwem pracy
PublicationW artykule przedstawiono możliwość wykorzystania controllingu do badania zagrożeń w procesie pracy. Dla oceny rozwiązań usprawniających wprowadzono pojęcie oszczędności zasobu typu praca i typu materiał, zużywanych w procesie realizacji zadań wytwórczych. Artykuł podkreśla możliwość osiągania efektów ekonomicznych (ograniczenia kosztów) w wyniku poprawy warunków pracy.CONTROLLING IN WORK SAFETY MANAGEMENTThe article presents the...
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Tests of bond between concrete and steel bars – literature background and program of own research
PublicationThis article deals with the issue of the bond between concrete and reinforcement. The bond is crucial for reinforced concrete elements because it is possible to transfer forces (stresses) from concrete to the reinforcement. Basic information related to the cooperation of concrete and rebars was recalled in the article. Selected issues concerning theoretical and numerical analysis as well as experiments of the bond phenomenon were...
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On the influence of a surface roughness on propagation of anti-plane short-length localized waves in a medium with surface coating
PublicationWe discuss the propagation of localized surface waves in the framework of the linear Gurtin–Murdoch surface elasticity and taking into account a roughness of a free boundary. We derive a boundary-value problem for anti-plane motions with curvilinear boundary and surface stresses. Using the asymptotic technique developed earlier, we obtain the form of a localized wave and analyze its amplitude evolution. As the main result we present...
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Anti-plane surface waves in media with surface structure: Discrete vs. continuum model
PublicationWe present a comparison of the dispersion relations derived for anti-plane surface waves using the two distinct approaches of the surface elasticity vis-a-vis the lattice dynamics. We consider an elastic half-space with surface stresses described within the Gurtin–Murdoch model, and present a formulation of its discrete counterpart that is a square lattice half-plane with surface row of particles having mass and elastic bonds different...
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Prosthetic Elements Made of the Ti-13Zr-13Nb Alloy by Selective Laser Melting
PublicationThe fabrication of the prosthetic foundations and bridges from the Ti-13Zr-13Nb alloy is described. The process was started from CAD/CAM design of 3D models of the foundations based on scanning of patient`s mouth. Next, 3D models were transformed into *.stl files for the manufacturing stage and then the manufacturing process by means of the selective laser melting with the SLM Realizer 100 equipment was made. The intrinsic structure...
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Properties of surface layers of duplex stainless steel after burnishing processes
PublicationStress corrosion cracking resistance of cold worked layers of 25 Cr duplex stainless steel grade UR52N+ has been investigated. The surface layers were performed through burnishing treatment. The residual stresses at surface layers were determined using grazing angle incidence X-ray diffraction method (g-sin2 Ψ). Corrosion tests were performed with the use of Slow Strain Rate Test technique in boiling 35% MgCl2 solution. It has...
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ATTEMPT AT EVALUATING THE INFLUENCE OF BENDING STRESS ON SHAFT WEAR PROCESSES IN WATER LUBRICATED SLIDING BEARING WITH A RUBBER BUSHING
PublicationWater lubricated bearings find increasingly wide application in shipbuilding or hydro–power industry, the popularity stemming from their numerous advantages. Unfortunately, as it turns out, water lubricated bearings do not always meet expectations, as on occasion they become subject to intense, premature wear which requires costly repair. One of the still unexplained phenomena is the process of excessive bearing wear, in particular...
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Numerical analysis and in situ tests of the Grot Rowecki Bridge in Warsaw
PublicationThe paper presents the FEM analysis of the reconstructed the Grot-Rowecki Bridge over Vistula river in Warsaw. The bridge has seven spans and consists of two independent structures with the longest spans of 120 m. After reconstruction the bridge is over 10 m wider. The numerical, nonlinear analysis has been con-ducted on a global and local FEM models. These models are defined so as they strictly comply with global structural bridge...
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REINFORCED CONCRETE SUPPORTING CONSTRUCTION OF THE STADIUM COVER FOR EURO 2012 IN GDAŃSK
PublicationIn the article structural issues that connected with the reinforced concrete supporting construction of the stadium roofing for EURO 2012 in Gdańsk were described. In the first part of the article the concept of stadium foundation were described. In the second the static - strength analysis for two variants fastening together individual foundation elements were made. The two assumed geometrically different concept of foundation...
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Fracture mechanics model of cutting power versus widespread regression equations while wood sawing with circular saw blades
PublicationA comparison of the theoretical cutting power consumption results forecasted with the model (FM_CM model) which include work of separation (fracture toughness) in addition to plasticity and friction, and two widespread regression equations while wood sawing with circular saw blades has been described. in and cutting power consumption forecasted. In computations of the cutting power consumption during rip sawing of Scots pine wood...
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Empirical verification in industrial conditions of fracture mechanics models of cutting power prediction
PublicationA comparison of experimental results obtained in the industrial conditions at a sawmill located in the Baltic Natural Forest Region (PL) and theoretical cutting power consumption forecasted with the models which include work of separation (fracture toughness) in addition to plasticity and friction has been described. In computations of cutting power consumption during rip sawing of Scots pine wood (Pinus sylvestris L.) values of...
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Effect of Pin Shape on Thermal History of Aluminum-Steel Friction Stir Welded Joint: Computational Fluid Dynamic Modeling and Validation
PublicationThis article studied the effects of pin angle on heat generation and temperature distribution during friction stir welding (FSW) of AA1100 aluminum alloy and St-14 low carbon steel. A validated computational fluid dynamics (CFD) model was implemented to simulate the FSW process. Scanning electron microscopy (SEM) was employed in order to investigate internal materials’ flow. Simulation results revealed that the mechanical work...
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Copper Slag as a Potential Waste Filler for Polyethylene-Based Composites Manufacturing
PublicationThe present study aimed to analyze the application of waste material from copper production– copper slag (ŻŻL) as filler for composites based on the high-density polyethylene (HDPE). Copper slag filler was introduced in the amounts of 1–20 wt%, and its influence on the appearance (color analysis), chemical structure (Fourier-transform infrared (FTIR) spectroscopy), microstructure (optical microscopy), as well as static (tensile...
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IMPLANT USED IN HERNIA REPAIR UNDER PHYSIOLOGICAL MOVEMENTS OF HUMAN ABDOMEN
PublicationThe study deals with the mechanical behaviour of implant used in repair of abdominal hernia. The influence of orientation of the orthotropic implants in different areas of abdominal wall is studied.
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Reclaiming ground tire rubber at low temperatures: benefits and limitations
PublicationLower extrusion temperatures during rubber reclamation lead to a reduction in toxic degradation products and improve the mechanical properties of vulcanizates, at the expense of reduced processability.
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Ocena stanu technicznego konstrukcji zgarniaczy będących na wyposażeniu osadników wstępnych Grupowej Oczyszczalni Ścieków „DĘBOGÓRZE
PublicationOsadniki wstępne typu DORRA – 4 szt., o pojemności 1830 m3, wyposażone są w elementy mechaniczne do kierunkowego przemieszczania się osadu w kierunku leja centralnego. Celem pracy jest ocena stany technicznego części mechanicznej, a w szczególności: - konstrukcji zespołu zgarniania części pływających oraz osadu. - zespołu napędu i sterowania, - zespołu napędu i jazdy. Pierwsze dwa zespoły będą oceniane również z punktu widzenia...
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New 3D printable filaments with nanodiamonds, physicochemical additives characteristics and electrochemical activity
Open Research DataThis dataset contains the physicochemical analyses (XRD, Raman spectroscopy, BET analyses) and electrochemical analyses (CV, EIS) for a new 3D-printable composite has been developed dedicated to electroanalytical applications. Two types of diamondised nanocarbons - detonation nanodiamonds (DNDs) and boron-doped carbon nanowalls (BCNWs) - were added...