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Wyniki wyszukiwania dla: SHORT-LIFE COMPOSITES
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Measurement of expenditure efficiency of Polish cities with county rights in the context of quality of life
PublikacjaThe article is devoted to the measurement of efficiency of overall expenditures. The purpose of the study is to evaluate the efficiency of use of budget resources by local government units in the context of fostering quality of life. The subject of the study is 65 Polish cities with county rights (county status). Calculations were carried out using Data Envelopment Analysis (DEA). The results of analysis confirm the two research...
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Mechanical Properties, Microstructure and Surface Quality of Polypropylene Green Composites as a Function of Sunflower Husk Waste Filler Particle Size and Content
PublikacjaAgricultural waste is a still untapped source of materials that can, in case of proper utilization, significantly improve the sustainability of polymers and their composites. In this work, polymer composites based on isotactic polypropylene were produced incorporating ground sunflower husk in the amount of 10 wt% and 20 wt%. The work’s main objective is to evaluate how preliminary fractioning of this agricultural waste filler affects...
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Rotational molding of polylactide (PLA) composites filled with copper slag as a waste filler from metallurgical industry
PublikacjaThe research work carried out so far indicates the ever wider possibilities and demand for shaping composite products in the rotational molding technology. This trend was the main reason to use waste-based filler from the metallurgical process as a filler for manufacturing polylactide (PLA)-based remolded composites. Copper slag (CS) was introduced in the single-step processing method to PLA matrix at 5, 10, 20, and 35 wt%. The...
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Manufacturing and Recycling Impact on Environmental Life Cycle Assessment of Innovative Wind Power Plant Part 1/2
PublikacjaWind power plants are considered as ecologically-clean source of energy. However, manufacturing processes cannot be treated that way. Manufacturing processes consume huge amount of electrical and thermal energy and significant amount of materials, e.g. steel, polymers, oils and lubricants. All of the above could be potentially harmful for environment. There are not many works and publications regarding life-cycle analysis of wind...
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Justifying the prolongation of the service life of the bearing structure of a tank car when using Y25 bogies
PublikacjaThis paper substantiates the use of Y25 bogies under tank cars in order to prolong their service life. The reported study has been carried out for a tank car with rated parameters, as well as the actual ones, registered during full-scale research. Mathematical modeling was performed to determine the basic indicators of the tank car dynamics. The differential equations of motion were solved by a Runge-Kutta method using the Mathcad...
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Perceived neighborhood disorder and quality of life: The role of the human-place bond, social interactions, and out-group blaming.
PublikacjaFour studies were carried out to examine how neighborhood disorder, human-place bonds, relationships among neighbors, and urban quality of life are related and what role blaming nonresidents plays in these relationships. In the first study, local identity was a significant mediator of the relationship between neighborhood disorder and quality of life. In the second study, we found that participants exposed to vignettes describing...
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Analysis of effect of overloaded vehicles on fatigue life of flexible pavements based on weigh in motion (WIM) data
PublikacjaOverloaded vehicles have a significant impact on pavement fatigue life and distress. As the studies show, the phenomena intensify when the control of traffic is poor. The paper presents the results of the research including analysis of weigh in motion data from eight stations and analysis of asphalt pavement fatigue caused by mixed traffic. Distributions of vehicles axles load including the multiple axles effects are presented....
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Short-term Price Reaction to Involuntary Bankruptcies Filed in Bad Faith: Empirical Evidence from Poland
PublikacjaPurpose: Assessing the reaction of the prices of shares of companies listed in the Warsaw Stock Exchange to the public disclosure of information about the filing a bankruptcy petition in bad faith by creditors. Design/Methodology/Approach: Event study analysis. Findings: It can therefore be assumed that the filing of an unfounded bankruptcy petition does not, in the short term, have a statistically significant negative impact on...
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Sustainable Strategy for Algae Biomass Waste Management via Development of Novel Bio-Based Thermoplastic Polyurethane Elastomers Composites
PublikacjaThis work concerns the waste management method of algae biomass wastes (ABW). For this purpose, we prepared bio-based thermoplastic polyurethane elastomer (bio-TPU) composites. Algae biomass wastes are derived from algal oil extraction of Chlorella vulgaris and from biomass of Enteromorpha and Zostera marina. ABWs were used in the bio-TPUs composites as a filler in the quantity of 1, 5, 10, and 15 wt.%. The bio-based composites...
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A comparative study on selective properties of Kraft lignin–natural rubber composites containing different plasticizers
PublikacjaEffect 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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Second Life - Problems with the Prolongation of Reality
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Digital document life cycle development
PublikacjaPrzedstawiono model DDLC wytwarzania interaktywnych dokumentów cyfrowych z ich pierwowzorów papierowych. Model DDLC opracowany w ramach 5 PR UE IST-2002-33441 MEMORIAL wyróżnia 6 faz i odpowiednie grupy funkcjonalności narzędzi do ich realizacji. Cykl wytwarzanie realizuje politykę całkowitej kontroli jakości, wykorzystującej specjalnie opracowaną metodę Visual GQM.
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The Impact of Hybrid Flame Retardant Compositions on the Performance of Foamed Flexible Polyurethane/Ground Tire Rubber Composites
PublikacjaCurrent sustainability-oriented trends affect polyurethane (PU) materials and stimulate the incorporation of recycled or waste-based materials as fillers. Ground tire rubber (GTR) poses as an auspicious candidate due to the excellent performance of car tires. Despite the benefits related to the mechanical performance, it contributes to the increasing flammability of the resulting composites. Herein, presented work assessed the...
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Fatigue life improvement using low transformation temperature weld material with measurement of residual stress
PublikacjaWelding processes often produce high levels of tensile residual stress. Low transformation temperature (LTT) welding wires utilise phase transformation strains to overcome the thermal contraction of a cooling weld. In this paper, the residual stress within each weld was quantified using the milling/strain gauge method, being the strain change measured as the weldment was milled away. The fatigue tests were conducted under uniaxial...
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Simulation of Life Raft Motions on Irregular Wave - An Analysis of Situations Leading to Raft Capsizing
PublikacjaSuccessful rescue action at sea is based on a. o. a correct choice of rescue means and their reliability. Operational characteristics of life-saving appliances determine their performance in a given water area. Therefore they affect duration time of rescue action and decide this way on survival time of shipwrecked persons. This paper presents impact of characteristics of circular inflatable life rafts on their dynamics in a...
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The Effect of Surface Treatment with Isocyanate and Aromatic Carbodiimide of Thermally Expanded Vermiculite Used as a Functional Filler for Polylactide-Based Composites
PublikacjaIn this work, thermally expanded vermiculite (TE-VMT) was surface modified and used as a filler for composites with a polylactide (PLA) matrix. Modification of vermiculite was realized by simultaneous ball milling with the presence of two PLA chain extenders, aromatic carbodiimide (KI), and 4,4’-methylenebis(phenyl isocyanate) (MDI). In addition to analyzing the particle size of the filler subjected to processing, the efficiency...
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Observing its long-term effects on a short-term, multi-day evaluation of the effectiveness of hearing aid use
PublikacjaThe main objective of the research study was to develop a method for evaluating the effectiveness of hearing protection with hearing aids tailored to the needs and prevailing conditions in the acoustic environments where the elderly most often reside. The method was also intended to estimate the benefits of hearing aids and allow prediction of such an effect based on a short-term trial. It is noteworthy that a short-term evaluation...
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Short-Period Information in GPS Time Series
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Wireless short-range device for wind generators
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Arc Ignition Process in Short Fuses Element
PublikacjaPrzedstawiono wyniki badań zapłonu łuku elektrycznego w topiku w warunkach dużej stromości narastania gęstości prądu, do 5.19 9 A s-1 mm-2. Wyznaczono podziałkę rozpadu topika (0,04-0,12 mm) oraz napięcie zapłonu na elementarnej przerwie topika (20-30 V). Wykazano w badaniach doświadczalnych modelu fizycznego topika rozpad i ponowne łączenie sąsiednich elementarnych przerw.
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Methods for biomaterials printing: A short review and perspective
PublikacjaPrinting technologies have opened larger windows of innovation and creativity to biomaterials engineers by providing them with the ability to fabricate complex shapes in a reasonable time, cost, and weight. However, there has always been a trouble with function adjusting in printing technologies in view of the multiplicity of materials and apparatus parameters. 3D printing, also known as additive manufacturing, revolutionized biomaterials...
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Strain sequence effect on fatigue life and fracture surface topography of 7075-T651 aluminium alloy
PublikacjaThe paper studies the effect of strain-loading sequence on fatigue lifetime and fracture surface topographies in 7075-T651 aluminum alloy specimens. Fatigue tests were performed in two ways: (i) constant-amplitude loading and (ii) two series of variable amplitude loading with non-zero mean strain values. The topography of the fatigue fractures was measured over their entire surfaces with the help of an optical confocal measurement...
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Entropic Measures of Complexity of Short-Term Dynamics of Nocturnal Heartbeats in an Aging Population
PublikacjaTwo entropy-based approaches are investigated to study patterns describing differences in time intervals between consecutive heartbeats. The first method explores matrices arising from networks of transitions constructed following events represented by a time series. The second method considers distributions of ordinal patterns of length three, whereby patterns with repeated values are counted as different patterns. Both methods provide...
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The environmental dimension of city dwellers’ quality of life and the city’s social and spatial variability
PublikacjaThe purpose of this paper is to attempt an analysis of the environmental dimension of the quality of life using quantitative surveys conducted among residents of Gdańsk. In the paper, we make reference to the theoretical assumptions ensuing from the concept of a comprehensive and integrated approach to the development of the urban environment, whilst noting the profound impact humans bring to their evaluation of the environmental...
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Enzymatic and Chemical Cross-Linking of Bacterial Cellulose/Fish Collagen Composites—A Comparative Study
PublikacjaThis article compares the properties of bacterial cellulose/fish collagen composites (BC/Col) after enzymatic and chemical cross-linking. In our methodology, two transglutaminases are used for enzymatic cross-linking—one recommended for the meat and the other proposed for the fish industry—and pre-oxidated BC (oxBC) is used for chemical cross-linking. The structure of the obtained composites is characterized by scanning electron...
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A variational approach of homogenization of piezoelectric composites towards piezoelectric and flexoelectric effective media
PublikacjaThe effective piezoelectric properties of heterogeneous materials are evaluated in the context of periodic homogenization, whereby a variational formulation is developed, articulated with the extended Hill macrohomogeneity condition. The entire set of homogenized piezoelectric moduli is obtained as the volumetric averages of the microscopic properties of the individual constituents weighted by the displacement and polarization...
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Sustainable utilization of copper post-flotation waste in cement composites
PublikacjaThe current way of managing the copper ore flotation waste is by placing it in waste neutralization facilities. However, flotation waste has great potential in application in cement composites. The article presents the detailed characteristics of post-flotation waste (PFW) and three types of cements: CEM I, CEM II/B-V, and CEM III/A, 42.5 MPa class. The post-flotation waste added for 20% of the cement mass increase the water demand...
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Waves in a short cable at low frequencies, or just hand-waving? What does physics say? (Invited paper)
PublikacjaWe address the question of low-frequency signals in a short cable, which are often considered as waves in engineering calculations. Such an assumption violates several laws of physics, but exact calculations can be carried out via linear network theory.
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On the use of the cumulative strain energy density for fatigue life assessment in advanced high-strength steels
PublikacjaIn this paper, the applicability of the cumulative strain energy density is explored as a fatigue indicator parameter for advanced high-strength steels subjected to strain-controlled conditions. Firstly, the cyclic stress-strain responses of nine steels, selected from three multiphase families, encompassing different elemental compositions and different heat treatment routes, were studied. Then, the predictive capabilities of the...
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Structure and Interactions in Chitosan Composites
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Manufacturing and Recycling Impact on Environmental Life Cycle Assessment of Innovative Wind Power Plant Part 2/2
PublikacjaThe process of conversion of wind kinetic energy into electricity in innovative wind power plant emits practically no harmful substances into the environment. However, the production stage of its components requires a lot of energy and materials. The biggest problem during production plan-ning process of an innovative wind power plant is selection of materials and technologies and, consequently, the waste generated at this stage....
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Investigating the Effects of Geometrical Parameters of Re-Entrant Cells of Aluminum 7075-T651 Auxetic Structures on Fatigue Life
PublikacjaIn this study, the effects of two geometrical parameters of the re-entrant auxetic cells, namely, internal cell angle (θ) and H/L ratio in which H is the cell height, and L is the cell length, have been studied on the variations of Poisson’s ratio and fatigue life of Aluminum 7075-T6 auxetic structures. Five different values of both the H/L ratio and angle θ were selected. Numerical simulations and fatigue life predictions have...
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The Impact of Isocyanate Index and Filler Functionalities on the Performance of Flexible Foamed Polyurethane/Ground Tire Rubber Composites
PublikacjaThe structure and performance of polyurethane (PU) foams are strongly driven by the stoichiometry of the polyaddition reaction, quantitatively described by the isocyanate index. It determines the balance between isocyanate and hydroxyl groups in the reacting system and is affected by the introduction of additional functionalities originated, e.g., from applied fillers. Nevertheless, this issue is hardly taken into account in research...
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Effect of multi-walled carbon nanotubes properties on the photocatalytic activity of bismuth-based composites synthesised via an imidazolium ionic liquid
PublikacjaThe use of various types of multi-walled carbon nanotubes in the synthesis of bismuth oxybromide semiconductors via imidazolium ionic liquid was studied in detail. The effect of the MWCNT shape, specific surface area, and various diameters on the morphology, surface properties and photoactivity of the Bi-based composites has been investigated for the first time. So far, the literature has only shown the enhancement of photocatalytic...
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THE IMPACT OF GROUND TIRE RUBBER TREATMENT ON THE THERMAL CONDUCTIVITY OF FLEXIBLE POLYURETHANE/GROUND TIRE RUBBER COMPOSITES
PublikacjaWaste car tires are burdensome waste, and their utilization is crucial for the natural environment. In many countries, the primary method of their recycling is energy recovery, performed by simple combustion. However, material recycling is much more effective and significantly more beneficial for the natural environment. It results in the generation of ground tire rubber, which can be used to produce polymerrubber composites. It...
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Fractographic-fractal dimension correlation with crack initiation and fatigue life for notched aluminium alloys under bending load
PublikacjaIn this study, fatigue fracture surfaces of aluminium alloy 2017-T4 notched specimens were investigated under cyclic bending to find an alternative failure loading index.. The surface topographies were measured on the entire fracture area with an optical profilometer for different loading conditions. Fatigue crack initiation life Ni and total fatigue life Nf were examined using standard surface topography parameters (such as, root...
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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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Ground lemon and stevia leaves as renewable functional fillers with antioxidant activity for high-density polyethylene composites
PublikacjaThe development of new sustainable material solutions in the processing of thermoplastic polymers concerns both the application of biopolymers and the use of valorized plant derivatives as fillers and modifiers of petrochemical polymers. Herein, the possibility of using unprocessed raw parts of two commonly used in the food industry leaves, i.e., lemon (LL) and stevia (ST), as active and functional fillers for high-density polyethylene...
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Synthesis and characterization of biopolyols through biomass liquefaction of wood shavings and their application in the preparation of polyurethane wood composites
PublikacjaThe sustainability of production systems in wood processing, wood industry, and wooden waste disposal is an important issue for European industry and society. Proper development of products based on renewable wood resources gives an opportunity to provide materials with long-term environmental, social, and economic sustainability. This study aims to establish a new way of forestry and agricultural waste materials utilization by...
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Influence of Giant Reed (Arundo Donax L.) Culms Processing Procedure on Physicochemical, Rheological, and Thermomechanical Properties of Polyethylene Composites
PublikacjaGiant reed (Arundo donax L.) is a plant species with a high growth rate and low requirements, which makes it particularly interesting for the production of different bioproducts, including natural fibers. This work assesses the use of fibers obtained from reed culms as reinforcement for a high-density polyethylene (HDPE) matrix. Two different lignocellulosic materials were used: i) shredded culms and ii) fibers obtained by culms...
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Structural and physico-mechanical properties of natural rubber/GTR composites devulcanized by microwaves: Influence of GTR source and irradiation time
PublikacjaGround tire rubber from car and truck was modified using microwave irradiation at variable time. The irradiated ground tire rubber was used as filler in composites based on natural rubber. The composites, with high content of ground tire rubber, were prepared using an internal batch mixer and subsequently cross-linked at 160℃. The influence of the ground tire rubber source (car/truck) and irradiation time on structure, physico-mechanical...
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Effect of pavement roughness and vehicle dynamic loads on decrease of fatigue life of flexible pavements
PublikacjaDue to the fact that pavement surfaces are not ideally even, dynamic loads of vehicle axles deviate from static loads. Higher dynamic loads contribute to faster pavement distress. The distribution of dynamic loads is similar to normal distribution and can be described by static load and factors DI (dynamic impact) and DLC (dynamic load coefficient). With the deterioration of pavement condition its evenness decreases as well and...
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The analysis of the influence of the corrosion protection method of selected steel elements on the steel structure life cycle costs
PublikacjaSteel products are widely used in the construction for the performance of essential and additional elements of engineering structures. They are characterized by high tensile strength, compression and bending, the structure homogeneity, the possibility of assembly regardless of the season and climatic conditions, ease of processing and the possibility of almost any shape. The main disadvantage of steel structures is their high susceptibility...
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Entropy Measures of heart rate variability for short ECG datasets in patients with congestive heart failure
PublikacjaWe investigated the usefulness of entropy measures calculated for short ECG series in distinguishing healthy subjects from patients with congestive heart failure (CHF). Four entropy measures were tested: Approximate Entropy (ApEn), Sample Entropy (SampEn), Fuzzy Entropy (Fuzzy En) and Permutation Entropy (PE), each computed for ECG series of 1000, 500, 250 and 100 RR intervals. We found that with a reduction of the data set length...
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Entropy measures of heart rate variability for short ECG datasets in patients with congestive heart failure
PublikacjaWe investigated the usefulness of entropy measures calculated for short ECG series in distinguishing healthy subjects from patients with congestive heart failure (CHF). Four entropy measures were tested: Approximate Entropy (ApEn), Sample Entropy (SampEn), Fuzzy Entropy (FuzzyEn) and Permutation Entropy (PE), each computed for ECG series of 1000, 500, 250 and 100 RR intervals. We found that with a reduction of the data set length...
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Synergistic Effects of Bitumen Plasticization and Microwave Treatment on Short-Term Devulcanization of Ground Tire Rubber
PublikacjaGround tire rubber (GTR) was mechano-chemically modified with road bitumen 160/220 and subsequently treated using a microwave radiation. The combined impact of bitumen 160/220 content and microwave treatment on short-term devulcanization of GTR was studied by thermal camera, wavelength dispersive X-ray fluorescence spectrometry (WD-XRF), static headspace, and gas chromatography-mass spectrometry (SHS-GC-MS), thermogravimetric analysis...
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More than just a beer – Brewers' spent grain, spent hops, and spent yeast as potential functional fillers for polymer composites
PublikacjaBeer is among the most popular beverages in the world, with the production distributed uniformly between the biggest continents, so the utilization of brewing by-products is essential on a global scale. Among their potential recipients, the plastics industry offers extensive range of potential products. Herein, the presented study investigated the application of currently underutilized solid brewing by-products (brewers' spent...
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Measurements of Thermal Conductivity of LWC Cement Composites Using Simplified Laboratory Scale Method
PublikacjaThe implementation of low-energy construction includes aspects related to technological and material research regarding thermal insulation. New solutions are sought, firstly, to reduce heat losses and, secondly, to improve the environment conditions in isolated rooms. The effective heat resistance of insulating materials is inversely proportional to temperature and humidity. Cement composites filled with lightweight artificial...
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Investigation of Wood Flour Size, Aspect Ratios, and Injection Molding Temperature on Mechanical Properties of Wood Flour/Polyethylene Composites
PublikacjaIn the present research, wood flour reinforced polyethylene polymer composites with a coupling agent were prepared by injection molding. The effects of wood flour size, aspect ratios, and mold injection temperature on the composites’ mechanical properties were investigated. For the preparation of the polymer composites, five different formulations were created. The mechanical properties including tensile strength and the modulus,...
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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...