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Determination of Mechanical Energy Loss in Steady Flow by Means of Dissipation Power
PublikacjaWhen systems of simple geometry like pipes or regular channels are considered, the mechan- ical energy loss of the fluid flow can be expressed by local and longitudinal empirical energy loss coefficients. However, in the case of large spatially distributed objects, there are no simple approaches to this task. In practice, general recommendations addressing different types of objects are used, but they usually provide very coarse...
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Effect of the working liquid compressibility on the picture of volumetric and mechanical losses in a high pressure displacement pump used in a hydrostatic drive Part II Mechanical losses in a pump
PublikacjaŚciśliwość cieczy roboczej może znacząco zmienić wartości i proporcje współczynników strat objętościowych i mechanicznych w pompie wyporowej zastosowanej w układzie napędu hydrostatycznego. Wpływ ten jest szczególnie widoczny w trakcie pracy pod wysokim ciśnieniem a także wówczas, gdy występuje zapowietrzenie cieczy roboczej. W części II przedstawiono model matematyczny momentu strat mechanicznych w pompie oraz jego laboratoryjną...
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Theoretical models of the torque of mechanical losses in the pump used in a hydrostatic drive
PublikacjaPrzedstawiono modele teoretyczne i matematyczne momentu strat mechanicznych występujących w pompie o stałej teoretycznej wydajności qPt na obrót wału (o stałej teoretycznej objętości roboczej VPt) bądź o zmiennej geometrycznej wydajności qPgv na obrót wału (o zmiennej geometrycznej objętości roboczej VPgv). Modele mają służyć badaniom laboratoryjnym i symulacyjnym strat energetycznych w pompie umożliwiającym ocenę sprawności energetycznej...
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Theoretical and mathematical models of the torque of mechanical losses in a hydraulic rotational motor for hydrostatic drive
PublikacjaW pracy przedstawiono modele teoretyczne i matematyczne momentu strat mechanicznych występujących w silniku hydraulicznym obrotowym o stałej teoretycznej chłonności qMt silnika na obrót wału (o stałej teoretycznej objętości roboczej VMt silnika) i o zmiennej chłonności qMgv = bM qMt na obrót wału (o zmiennej geometrycznej objętości roboczej VMgv silnika). Modele mają służyć badaniom laboratoryjnym i symulacyjnym strat energetycznych...
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The Influence of Water and Mineral Oil on Mechanical Losses in a Hydraulic Motor for Offshore and Marine Applications
PublikacjaIn this paper, mechanical losses in a hydraulic motor supplied with water and mineral oil (two liquids having significantly different viscosity and lubricating properties) are described and compared. The experimental tests were onducted using a special design (prototype) of a hydraulic satellite motor. The design of the satellite motor is presented. This motor was developed to supply both with water and mineral oil and features...
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THE INFLUENCE OF WATER AND MINERAL OIL ON MECHANICAL LOSSES IN THE DISPLACEMENT PUMP FOR OFFSHORE AND MARINE APPLICATIONS
PublikacjaIn this paper mechanical losses in a positive displacement pump supplied with water and mineral oil (two liquids having significantly different viscosity and lubricating properties) are described and compared. The experimental tests were conducted using a special design (prototype) of a satellite pump. The design of the satellite pump is presented in the article. The pump features a non-circular tooth working mechanism. This pump...
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Effect of the working liquid compressibility on the picture of volumetric and mechanical losses in a high pressure displacement pump used in a hydrostatic drive. Part I Energy losses in a drive system, volumetric losses in a pump
PublikacjaŚciśliwość cieczy roboczej może znacząco zmienić wartości i proporcje współczynników strat objętościowych i mechanicznych w pompie wyporowej zastosowanej w układzie napędu hydrostatycznego. Wpływ ten jest szczególnie widoczny w trakcie pracy pod wysokim ciśnieniem a także wówczas, gdy występuje zapowietrzenie cieczy roboczej. W części I przedstawiono wykres zaproponowany przez autora, wzrostu mocy w układzie napędu hydrostatycznego...
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Effect of the working liquid compressibility on the picture of volumetric and mechanical losses in a high pressure displacement pump used in a hydrostatic drive. Part I Energy losses in a drive system, volumetric losses in a pump
PublikacjaŚciśliwość cieczy roboczej może znacząco zmienić wartości i proporcje współczynników strat objętościowych i mechanicznych w pompie wyporowej zastosowanej w układzie napędu hydrostatycznego. Wpływ ten jest szczególnie widoczny w trakcie pracy pod wysokim ciśnieniem a także wówczas, gdy występuje zapowietrzenie cieczy roboczej. W części I przedstawiono wykres zaproponowany przez autora, wzrostu mocy w układzie napędu hydrostatycznego...
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Mechanical, thermo-mechanical properties of epoxy/glass composites with submicron particles
PublikacjaIn this research the influence of submicron zinc oxide and silicon dioxide particles on mechanical, thermo-mechanical properties of epoxy matrix composites reinforced with glass fibres was investigated. Composites were fabricated using hand lay-up method. Materials contained 39-41 wt.% of glass fibres. The bending tests, dynamic mechanical analysis and tribological tests were performed on each group of composites and also for...
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Energy Loss Coefficients ki in a Displacement Pump and Hydraulic Motor used in Hydrostatic Drives
PublikacjaThe article aims at defining and analysing the energy loss coefficients in design solutions of rotating displacement machines, with a piston machine as an example. The energy losses observed in these machines include mechanical loss, volumetric loss, and pressure loss. The scale and relations between these losses in different machines depend on machine design and manufacturing quality, and on operating parameters. The operating...
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Influence of selected submicron inorganic particles on mechanical and thermo-mechanical properties of unsaturated polyester/glass composites
PublikacjaIn this paper, the influence of different submicron-scaled particles (zinc oxide, titanium dioxide, or silica) on mechanical and thermo-mechanical properties of unsaturated polyester matrix composites reinforced with glass fabric was investigated. Surface morphology of obtained composites was also examined. At first inorganic particles were mechanically dispersed into unsaturated polyester resin system as per the calculated weight...
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Rigid polyurethane foams modified with ground tire rubber - mechanical, morphological and thermal studies
PublikacjaRigid polyurethane foams, prepared by a single step method, were modified with the two types of ground tire rubber particles, i.e. untreated and thermo-mechanically reclaimed by using a co-rotating twin screw extruder. The foaming process as well as the structure and the physical, mechanical and thermal properties of the resulting foams were investigated. The presence of ground tire rubber decreased the velocity of polymerization....
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Inlet air fogging of marine gas turbine in power output loss compensation
PublikacjaThe use of inlet air fogging installation to boost the power for gas turbine engines is widely applied in the power generation sector. The application of fogging to mechanical drive is rarely considered in the literature [1]. This paper will cover some considerations relating to its application to gas turbines in ship drive. There is an important evaporative cooling potential throughout the world when the dynamic data is evaluated,...
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Injectable poloxamer/graphene oxide hydrogels with well‐controlled mechanical and rheological properties
PublikacjaAlthough significant progress has been made in the design and application of injectable hydrogels for biomedical applications, concurrent control of rheological and mechanical properties of injectable hydrogels has remained as an open challenge to the researchers. In this work, we introduce and put into practice a photo‐curable poloxamer (also known as Pluronic)/graphene oxide (Plu/GO) injectable hydrogel with well‐controlled rheological...
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Structure, morphology and mechanical behaviour of novel bio-based polyurethane composites with microcrystalline cellulose
PublikacjaThe aim of this work was to obtain bio-based polyurethane composites using biocomponents such as, bio-glycol, modified natural oil-based polyol, and microcrystalline cellulose (MCC). The prepolymer method was used to prepare the bio-based polyurethane matrix. Prepolymer synthesised from 4,4’-diphenylmethane diisocyanate (MDI) and a polyol mixture containing 75% wt. commercial polyether and 25% wt. hydroxylated soybean oils (H3)...
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Stability evaluation of the marine propulsion unit mechanical system bymeans of vibrations measurements and their analysis.
PublikacjaIn paper selected issues concerning vibration diagnosis of the mechanical system within marine propulsion units have been given. The analysis of vibration parameters was carried out on the basis of experimental examinations of a real object in which an exceedance of the allowable vibration's level had been observed. In the beginning, the vibration apparatus being on laboratory equipment of the Department of Ship Power Plants of...
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Stability evaluation of the marine propulsion unit's mechanical system by means of vibration measurements and their analysis
PublikacjaIn this paper selected issues concerning vibration diagnosis of the mechanical system within marine propulsion units have been given. The analysis of vibration parameters was carried out on the basis of experimental examinations of a real object in which an exceedance of the allowable vibration's level had been observed. In the beginning, the vibration apparatus being on laboratory equipment of the Department of Ship Power Plants...
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Core loss resistance impact on sensorless speed control of an induction motor using hybrid adaptive sliding mode observer
PublikacjaInduction motors (IMs) experience power losses when a portion of the input power is converted to heat instead of driving the load. The combined effect of copper losses, core losses, and mechanical losses results in IM power losses. Unfortunately, the core losses in the motor, which have a considerable impact on its energy efficiency, are not taken into account by the generally employed dynamic model in the majority of the studies. Due...
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On the Possibilities of Decreasing Power Loss in Large Tilting Pad Thrust Bearings
PublikacjaJournal Menu About this Journal Abstracting and Indexing Aims and Scope Article Processing Charges Articles in Press Author Guidelines Bibliographic Information Citations to this Journal Contact Information Editorial Board Editorial Workflow Free eTOC Alerts Publication Ethics Submit a Manuscript Table of Contents Abstract Full-Text PDF Full-Text HTML...
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Modyfikacja kompozytów elastomerowych NR za pomocą ligniny i glicerolizatu
PublikacjaPrzedmiotem opisanych w niniejszym artykule badań są wulkanizaty kauczuku naturalnego. Celem pracy było zbadanie wpływu ligniny oraz glicerolizatu na wybrane właściwości kompozytów zawierających kauczuk naturalny. Strukturę chemiczną przygotowanych materiałów potwierdzono, wykorzystując analizę spektroskopową w podczerwieni (FTIR). Zbadano również właściwości mechaniczne przy statycznym rozciąganiu, twardość, ścieralność oraz odbojność...
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Effect of ground tire rubber on structural, mechanical and thermal properties of flexible polyurethane foams
PublikacjaFlexible polyurethane foams were modified with two kinds of ground tire rubber, untreated and thermo-mechanically reclaimed. A reclamation process was performed in auto-thermal conditions, which reduced the cost of the process and decreased the environmental impact of devulcanization (e.g., emission of gases). The reclamation process was carried out in a continuous manner using a co-rotating twin screw extruder. The foams were...
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Three-Dimensional Printing of Bone Models
PublikacjaThe trabecular bone occurs, for example, in the femoral heads. Understanding the phenomenon of bone tissue degeneration can be the basis for the possibility of looking for alternative methods of surgical treatment of bone loss. The paper presents the results of the trabecular bone model, which was produced in additive manufacturing method with fused filament fabrication technology. The verification of the mechanical behavior of...
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ENERGY ANALYSIS OF THE PROPULSION SHAFT FATIGUE PROCESS IN A ROTATING MECHANICAL SYSTEM PART II IDENTIFICATION STUDIES – DEVELOPING THE FATIGUE DURABILITY MODEL OF A DRIVE SHAFT
PublikacjaThe article presents a continuation of research carried out concerning identification of energy consequences of mechanical fatigue within a propeller shaft in a rotating mechanical system, while working under conditions of the loss of the required alignment of shaft lines. Experimental research was carried out on a physical model reflecting a full-sized real object: i.e., the propulsion system of the ship. It is proven, by means...
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Physicochemical and Mechanical Performance of Freestanding Boron-Doped Diamond Nanosheets Coated with C:H:N:O Plasma Polymer
PublikacjaThe physicochemical and mechanical properties of thin and freestanding heavy boron-doped diamond (BDD) nanosheets coated with a thin C:H:N:O plasma polymer were studied. First, diamond nanosheets were grown and doped with boron on a Ta substrate using the microwave plasma-enhanced chemical vapor deposition technique (MPECVD). Next, the BDD/Ta samples were covered with nylon 6.6 to improve their stability in harsh environments and...
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Diagnostic testing of marine propulsion systems with internal combustion engines by means of vibration measurement and results analysis
PublikacjaIn this paper selected issues concerning vibration diagnosis of the mechanical system within marine propulsion units have been presented, carried out on the basis of experimental examinations of a real object in which an exceedance of the allowable vibration’s level had been observed. Used diagnosing system has been characterised. A procedure of longitudinal and transverse vibrations shaft lines of the mechanical system within...
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Structural, thermal and physico-mechanical properties of polyurethane/brewers’ spent grain composite foams modified with ground tire rubber
PublikacjaIn this work, brewers’ spent grain (BSG) and ground tire rubber (GTR) waste fillers were applied as low-cost reinforcement phase in rigid polyurethane foam (PUR). PUR/BSG/GTR composites were prepared by a single step method, using polyglycerol as partial substitute of commercially available petrochemical polyols. Foaming parameters, chemical structure, dynamic mechanical properties, thermal stability, physico-mechanical properties...
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Submicron inorganic particles as an additional filler in hybrid epoxy matrix composites reinforced with glass fibres
PublikacjaIn this study, the effect of selected submicron metal oxide (zinc oxide, titanium oxide) or non-metal oxide (silicon dioxide) particles on mechanical and thermo-mechanical properties of epoxy/glass composites was investigated. The applied epoxy resin was a diglycidyl ether of bisphenol-A cured with triethylenetetramine. As a reinforcement twill weave E-glass fabric was used. Hybrid composites (contained particulate and fibrous...
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Instantaneous impedance monitoring of synergistic effect between cavitation erosion and corrosion processes
PublikacjaThe most common method of determination of cavitation erosion resistance as well as the magnitude of erosion-corrosion synergistic interaction is based on the weight loss measurements. Nondestructive characterization of installations elements is in most cases impossible to perform. Also, such a measurement does not include local types of failure or alteration of operating conditions. There is an urge to elaborate a method for monitoring...
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Design of experiments approach for ultimate strength assessment of corroded stiffened plates
PublikacjaThe impact of corrosion degradation on the ultimate strength of stiffened plates subjected to compressive loading is investigated. The DoE technique is used considering different plate and column slenderness ratios and corrosion severity. The FE method, considering geometrical and material nonlinearities, is employed. A two-stage corrosion degradation model is adopted. Firstly, a uniform thickness loss is adopted to reflect the...
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Balancing energy processes in turbine engines
PublikacjaThe article discusses the issue of balancing energy processes in turbine engines in operation in aeronautic and PDULQHSURSXOVLRQV\VWHPVZLWKWKHDLPWRDQDO\VHDQGHYDOXDWH EDVLFRSHUDWLQJSDUDPHWHUV7KH¿UVWSDUWSUHVHQWV the problem of enormous amounts of energy needed for driving fans and compressors of the largest contemporary turbofan engines commonly used in long-distance aviation. The amounts of the transmitted power and the effect RIÀRZSDUDPHWHUVDQGFRQVWUXFWLRQDOSURSHUWLHVRIWKHHQJLQHV RQWKHLUSHUIRUPDQFHDQGUHDOHI¿FLHQF\DUH evaluated....
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Effect of sisal fiber filler on thermal properties of bio-based polyurethane composites
PublikacjaThis work is mainly focused on study of thermal and thermomechanical properties of obtained bio-based polyurethane (coded as bio-PU) composites via using different types of bio-components (bio-glycol, modified soybean oil and sisal fiber) in the procedure. The chemical structure, morphology and mechanical properties were also investigated and described in this manuscript in order to know more perfect characterization of produced...
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Advances in Modelling and Analysis of Strength of Corroded Ship Structures
PublikacjaThe present study reviews the recent advances in modelling and analyses the strength of corroded ship structures. Firstly, the time-variant methodologies that consider only the mean structural element thickness loss due to corrosion degradation are identified. Corrosion degradation is regarded as the phenomenon that causes uneven thinning of specimens. This has been captured by various researchers as the loss of mechanical properties...
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Reliability of Corroded Stiffened Plate Subjected to Uniaxial Compressive Loading
PublikacjaThe work is focused on the reliability of corroded stiffened plates subjected to compressive uniaxial load based on the progressive collapse approach as stipulated by the Common Structural Rules for Bulk Carriers and Oil Tankers, employing the limit state design. Two different cases have been investigated. In the first model, the corrosion degradation led to uniform thickness loss, whereas the mechanical properties were unchanged,...
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Giant Reed (Arundo donax L.) Fiber Extraction and Characterization for Its Use in Polymer Composites
PublikacjaThis work describes an extraction method for giant reed fibers from stems and leaves based on chemical soaking and crushing through a rolling mill. Obtained fibers, together with the shredded plant (stems + leaves), are characterized in terms of chemical composition, thermal stability, morphology, and crystallinity. Mechanical properties of fibers have also been assessed (single fiber tensile tests). The results show that the proposed...
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Effect of high loading of titanium dioxide particles on the morphology and selected properties of natural rubber-based composites
PublikacjaThe aim of this work was to prepare and characterize the natural rubber vulcanizates contained different amounts of titanium dioxide particles. At first rubber mixture was prepared using a laboratory two-roll mill and then samples were vulcanized in a hydraulic press. The formulation of rubber mixture and rubber-processing technique is based on our earlier investigations. Materials were obtained at the different titanium dioxide...
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Application of the neural networks for developing new parametrization of the Tersoff potential for carbon
PublikacjaPenta-graphene (PG) is a 2D carbon allotrope composed of a layer of pentagons having sp2- and sp3-bonded carbon atoms. A study carried out in 2018 has shown that the parameterization of the Tersoff potential proposed in 2005 by Ehrhart and Able (T05 potential) performs better than other potentials available for carbon, being able to reproduce structural and mechanical properties of the PG. In this work, we tried to improve the...
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Studies on the Combined Impact of Starch Source and Multiple Processing on Selected Properties of Thermoplastic Starch/Ethylene-Vinyl Acetate Blends
PublikacjaThermoplastic starch (TPS)/ethylene vinyl acetate (EVA) blends compatibilized with polyethylene-graft-maleic anhydride (PE-g-MA) were prepared from various native starches (potato, maize and waxy maize) and subjected to multiple extrusion cycles. Source of starch has significant impact on its composition, hence properties of obtained TPS and their blends with EVA. Higher content of amylopectin in waxy maize starch, comparing to...
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Drill holes decrease cancellous bone strength: A comparative study of 33 paired osteoporotic human and 9 paired artificial bone samples
PublikacjaThis study was designed to compare compressive strength of cancellous bone retrieved from the femoral head in a specimen with and without guide wire hole, with comparison to synthetic bone samples. Femoral heads retrieved from 33 patients who sustained femoral neck fractures and underwent hip arthroplasty were cut into cuboids leaving two matching samples from the same femoral head. Similar samples were prepared from synthetic femurs....
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PLA–Potato Thermoplastic Starch Filament as a Sustainable Alternative to the Conventional PLA Filament: Processing, Characterization, and FFF 3D Printing
PublikacjaThe growing popularity of the fused filament fabrication (FFF) 3D printing technology in science, industry, and in-home use is associated with an increased demand for high-quality polymer filaments. This study presents an in-depth characterization and analysis of a self-made bio-based polylactide (PLA)/thermoplastic potato starch (TPS) filament dedicated for the FFF 3D printing technology. The obtained results were compared with...
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Advanced numerical modelling for predicting residual compressive strength of corroded stiffened plates
PublikacjaAn advanced methodology for predicting the residual compressive strength of corroded stiffened plates is developed here using the non-linear finite element method. The non-uniform loss of a plate thickness is accounted for on a macro-scale. In contrast, mechanical properties are changed using the constitutive model to reflect the corrosion degradation impact on a micro-scale. Three different stiffened plate thicknesses are considered,...
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The ONETEP linear-scaling density functional theory program
PublikacjaWe present an overview of the ONETEP program for linear-scaling density functional theory (DFT) calculations with large basis set (planewave) accuracy on parallel computers. The DFT energy is computed from the density matrix, which is constructed from spatially localized orbitals we call Non-orthogonal Generalized Wannier Functions (NGWFs), expressed in terms of periodic sinc (psinc) functions. During the calculation, both the...
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Quantifying the effective mobilized RAP content during hot in-place recycling techniques
PublikacjaThe utilization of in-place recycling techniques is capable of consuming 100% reclaimed asphalt pavement (RAP). Hot in-place recycling (HIR) is one of the promising techniques to rehabilitate the pavements suffering from minor cracking issues through heat scarification, additive injecting, mechanical mixing, and compacting. However, the main concern of using 100% RAP in HIR remains as how much RAP can be activated and mobilized...
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Recuperator with microjet technology as a proposal for heat recovery from low-temperature sources
PublikacjaA tendency to increase the importance of so called dispersed generation, based on the local energy sources and the working systems utilizing both the fossil fuels and the renewable energy resources is observed nowadays. Generation of electricity on industrial or domestic scale together with production of heat can be obtained for example through employment of the ORC systems. It is mentioned in the EU directive 2012/27/EU for cogenerative...
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Experimental Study on Dynamics of Wooden House Wall Panels with Different Thermal Isolation
PublikacjaWood frame buildings are very popular in regions that are exposed to different dynamic excitations including earthquakes. Therefore, their seismic resistance is really important in order to prevent structural damages and human losses. The aim of the present paper is to show the results of experimental tests focused on the dynamic response of wall panels of a wooden frame building with thermal isolation made of mineral wool and...
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Biopolyols obtained via microwave-assisted liquefaction of lignin: structure, rheological, physical and thermal properties
PublikacjaThe present study examined the application of polyols obtained via microwave-assisted liquefaction of lignin in the production of rigid polyurethane foam. Lignin was liquefed in crude glycerol and 1,4-butanediol at diferent temperatures (130–170 °C), without a catalyst and using various biomass concentrations (15 and 30 wt%). The physicochemical properties, process yield, and FTIR-based identifcation of the obtained polyols were...
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Conductive Thermoplastic Polyurethane Nanocomposite Foams Derived from a Cellulose/MWCNTs Aerogel Framework: Simultaneous Enhancement of Piezoresistance, Strength, and Endurance
PublikacjaHigh conductivity and excellent mechanical properties of composite polymers favors their application as piezoresistive strain sensors. Nonetheless, it is difficult to develop composite polymers with desirable piezoresistance, mechanicaland durable properties. Herein, we developed conductive cellulose/MWCNTs aerogel using the freeze-drying technique. Besides, we explored the application of the highly-sensitive piezoresistive polymer...
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Experimental Evaluation of ND: YAG Laser Parameters and Sample Preparation Methods for Texturing Thin AISI 316L Steel Samples
PublikacjaIn mechanical and material engineering, the effect of laser texturing depends on many factors besides device specification, primarily the properties of the materials being processed, and, secondly, the preparation of the sample. Laser texturing of thin (<5 mm) samples is mostly performed utilizing short-pulse lasers, but depending on the power of the laser beam, the process can also be performed by using continuous operation lasers....
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Bio polyetherurethane composites with high content of natural ingredients: hydroxylated soybean oil based polyol, bio glycol and microcrystalline cellulose
PublikacjaIn our study, we focused on obtaining bio-polyurethane composites using bio-components such as bio glycol, modified natural oil-based polyol, and microcrystalline cellulose (MCC). The pre-polymer method was used to prepare the bio polyurethane matrix. Prepolymer was synthesized using 4,4’-diphenylmethane diisocyanate (MDI) and a polyol mixture containing 50 wt.% of commercial polyether and 50 wt.% of hydroxylated soybean oil (H3)....
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Effect of wet Hydrogen Sulfide on Carbon Steels Degradation in Refinery Based on Case Study
PublikacjaMaterial degradation caused by wet hydrogen sulfide (Wet H2S) is one of the major issues in refineries. Carbon steel is the main construction material used in refineries and is subjected not only to thickness loss but the hydrogen is the major concern. H2S leads to high atomic hydrogen penetration in steel which causes degradation in the form of blistering and/or cracking (HIC/SOHIC) and stress cracking in the area of welds and...
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Efficiency and proportions of waste tyre pyrolysis products depending on the reactor type—A review
PublikacjaThis article discusses the current use of different pyrolytic reactors, their constructions and operating principles regarding the yields of main products of waste tyre pyrolytic recycling. Whether one makes a larger or smaller profit, or even a loss due to a surcharge being levied on waste tyre recycling, depends on the sale of the pyrolysis products (gas, char, oil), the proportions and market prices of which differ. The cheapest...