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Tytuł:
Assessment of the resistance to external factors of low-density polyethylene modified with natural fillers
Autorzy:
Głogowska, K.
Majewski, Ł.
Gajdoš, I.
Mitaľ, G.
Powiązania:
https://bibliotekanauki.pl/articles/102811.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
natural filler
low-density polyethylene
injection molding
Opis:
The study reports the results of investigation of basic processing and thermal properties of low-density polyethylene modified with two types of natural filler: wheat bran and pumpkin seed hulls, their content ranging from 5% to 15% relative to the matrix. In addition, physical properties of the produced granulates are determined, i.e. the relationship between their density and the applied contents of the tested fillers. Furthermore, the study reports the results concerning longitudinal shrinkage, abrasion resistance and cold water absorption of injection molded tensile specimens.
Źródło:
Advances in Science and Technology. Research Journal; 2017, 11, 4; 35-40
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recycling of Coal Ash in Production of Low Density Masonry Unit
Autorzy:
Özgül, N.
Savaşçin, M.
Özkan, İ.
Powiązania:
https://bibliotekanauki.pl/articles/1030101.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
coal ash
recycling
low density
masonry unit
Opis:
Coal ash is a residue that is created when coal is burned by power plants to produce electricity. Coal ash is one of the largest types of industrial waste and causes environmental pollution. On the other hand, coal ash is potentially a valuable source of minerals, including SiO₂, Al₂O₃, CaO, MgO, Fe₂O₃, Na₂O and K₂O. This study aims to recycle the coal ash in production of low density masonry unit. Coal ash was characterized by chemical and X-ray diffraction analyses. The batches containing different ratios of coal ash and a brick making clay were prepared and shaped by cold pressing. The pressed samples were fired at 1050 and 1100°C. The physical properties such as water absorption, apparent porosity, linear shrinkage, and bulk density were determined. Microstructural observations were performed by using scanning electron microscopy. Based on the technological characteristics; it was observed that low density masonry units can be produced by using coal ash. This study supports the responsible recycling of coal ash by distinguishing beneficial use from disposal.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 430-432
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kinetic analysis of LDL apoB transport and metabolism in non-steady states
Autorzy:
Weryński, A.
Nahorski, Z.
Angelin, B.
Berglund, L.
Eriksson, M.
Powiązania:
https://bibliotekanauki.pl/articles/206021.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
biocybernetyka
apheresis
kinetic modelling
low density lipoprotein (LDL)
Opis:
In this paper a novel kinetic analysis is used for evaluation of the low density lipoprotein (LDL) apoB fractional catabolic rate (FCR) after LDL apheresis which creates a nonsteady state. The formulae for calculation of FCR, and LDL rate of appearance (Ra) as functions of time have been derived. Calculations for one normal and one familial hypercholesterolemic (FH) subjects showed that FCR as well as Ra exhibited variations which can be attributed to the circadian rhythm in LDL metabolism. LDL apheresis had a little impact on both Ra and FCR in normal as well as in FH subjects. However, Ra in FH subject was found to be much higher than - that in the normal subject.
Źródło:
Control and Cybernetics; 2000, 29, 1; 405-425
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low market density lines for ERTMS regional system
Autorzy:
Białoń, A.
Gradowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/393573.pdf
Data publikacji:
2009
Wydawca:
Polskie Stowarzyszenie Telematyki Transportu
Tematy:
ERTMS
linie o małej gęstości
low density lines
Opis:
The paper presents technical and formal aspects of the development and implementation of the ERTMS Regional. The main purpose of building the ERTMS Regional system is to create an ERTMS-based system which is maximally fitted to low-density lines. This paper presents differences between the specifications of ERTMS and ERTMS Regional systems. The article includes a technical description as well as the principles of ERTMS Regional, a description of the first stage of implementation, as well as an analysis of possible implementation of this system in Poland.
Źródło:
Archives of Transport System Telematics; 2009, 2, 2; 37-40
1899-8208
Pojawia się w:
Archives of Transport System Telematics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Were the oasis-cities of the southern branch of the Silk Road in Tarim Basin, China, dispersed urban complexes?
Czy miasta południowej odnogi Szlaku Jedwabnego w kotlinie Tarim w Chinach były rozproszonymi zespołami miejskimi?
Autorzy:
Hanus, Kasper
Powiązania:
https://bibliotekanauki.pl/articles/27312793.pdf
Data publikacji:
2021-12-30
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
Silk Roads
low-density urbanism
agro-urban landscape
Xinjiang
Opis:
This article reinterprets the urban pattern of the oases of southern Tarim Basin, which flourished in the first half of the first millennium C.E. using the dispersed urban complexes framework. Disperse urban centre, also known as a low-density urban complex, is a site that had an urban function, but its morphology was much different from compact cities of, for example, China or mediaeval Europe. Low-density urban complexes, like Tikal in Mesoamerica or Angkor in South-East Asia, despite their distinct urban functions, had the cityscape consisting of intermingled monumental agriculture, water management features and agricultural field. Thus, the oasis-cities of southern Tarim Basin were different from compact urban centres of neighbouring China and western Central Asia and showed some similarities to complexes like Tikal and Angkor. This article evaluates if those sites can be associated with low-density urbanism. Three selected sites, 尼雅 [Niya], 米兰 [Miran] and 樓蘭 [Loulan], have been evaluated for the presence of characteristic associated with low-density urbanism: dispersed monumental architecture, large scale anthropogenic landscapes modifications, and pattern of alternating housing clusters and agricultural fields. This can affect our understating of both the understanding of urbanism in the region and low-density urbanism on the global scale.
Źródło:
Folia Praehistorica Posnaniensia; 2021, 26; 89-121
0239-8524
2450-5846
Pojawia się w:
Folia Praehistorica Posnaniensia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wybrane aspekty oznaczania gęstości polietylenu małej gęstości
Selected aspects of low-density polyethylene density measurements
Autorzy:
Liszyńska, B.
Zieliński, J.
Marszałek, G.
Kowalska, L.
Kościańczuk, D.
Powiązania:
https://bibliotekanauki.pl/articles/278167.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Inżynierii Materiałów Polimerowych i Barwników
Tematy:
polietylen małej gęstości
polimery termoplastyczne
gęstość
low-density polyethylene
thermoplastic polymers
density
Opis:
Określono wpływ sposobu przygotowania próbek do oznaczeń na wartość gęstości polietylenu malej gęstości oraz podjęto próbę korelacji tych wielkości z wielkościami wyliczonymi na podstawie badań DSC. Przedmiot badań stanowiło osiem gatunków PE-LD. Gęstość oznaczano metodą zanurzeniową stosując próbki przygotowane w dwojaki sposób. Ustalono, że sposób kondycjonowania próbki ma widoczny, ale nieznaczny wpływ na wartość gęstości. Nie uzyskano zadowalającej korelacji pomiędzy wartościami gęstości oznaczonymi metodą zanurzeniową a wyliczonymi na podstawie DSC.
The influence was determined of the preparation of samples for the measurements on the density of low-density polyethylene and an attempt was made to correlate these values with density values calculated basing on DSC studies. The subject of this research were eight types of LDPE. The density was measured using immersion method for samples prepared in two ways. It was determined that the method of sample preparation has an observable but small influence on the measured value of density. No acceptable correlation was found between the values of density measured using the immersion method and the values calculated basing on DSC.
Źródło:
Przetwórstwo Tworzyw; 2015, T. 21, Nr 4 (166), 4 (166); 333-336
1429-0472
Pojawia się w:
Przetwórstwo Tworzyw
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Possibilities of Using Low-Density C-C Composites for Thermal Protection of Small Unmanned Aerial Vehicles
Autorzy:
Yanko, Taras
Datsenko, Roman
Karpenko, Hanna
Powiązania:
https://bibliotekanauki.pl/articles/36818980.pdf
Data publikacji:
2023
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
carbon-carbon composite material
low-density
fibre
laser weapon
carbonisation
Opis:
The study demonstrates the possibilities of using, as well as the features associated with the use of, unmanned aerial vehicles (UAVs) for military and peaceful purposes. Information is provided on the need to use components that would contribute towards ensuring thermal protection against modern laser weapons. The requirements for such materials are given, according to the field of application of the UAV. An analysis of the available materials that can be used to create thermal protection of UAVs against laser weapons is provided. The thermophysical characteristics of various materials are presented. The work presents technological features of production and properties of low-density carbon-carbon composite materials (CCCM). It is proposed to consider the prospects of using CCCM materials for not only the UAV structural components but also other purposes.
Źródło:
Transactions on Aerospace Research; 2023, 2 (271); 45-57
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties of moldings prepared from LDPE-pumpkin seed hulls blend
Autorzy:
Głogowska, K.
Sikora, J.
Dulebova, L.
Powiązania:
https://bibliotekanauki.pl/articles/102641.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
natural filler
low-density polyethylene
pumpkin seed hulls
injection molding
Opis:
In recent decades, standard polymer blends for different applications have been more and more often replaced by blends containing raw materials. The use of natural materials as filler in thermoplastics brings both economic and environmental benefits. The use of a given vegetable filler depends on the geographic location and natural occurrence of the vegetables in a given geographic region. In Poland, for instance, the pumpkin is one of such vegetables. They are used for producing oil which is pressed from pumpkin seeds. Pumpkin seeds are then collected, dried and purified to produce waste material in hull form. Particles of ground pumpkin seed hulls with varying sizes and weight-in-weight concentration ranging from 0% to 20% relative to the matrix are used as filler in low-density polyethylene. Pumpkin seed hulls are ground and sieved. Four fractions of hulls with different particle sizes are produced: <0.2 mm, 0.2-0.4 mm, 0.4-0.6 mm, 0.6-0.8 mm. The paper reports the results of investigation of the mechanical properties, i.e., strength properties determined by static tensile testing and hardness measurement, of injection molds produced at constant processing parameters. In addition, the cross sections of the obtained products are subjected to microscopic examination. Relationships are determined between tensile modulus, maximum tensile stress, tensile stress at yield, maximum tensile strain, tensile strain at yield as well as Shore hardness and weigh-in-weight concentration of the powdered natural filler and its grain sizes. Finally, relevant conclusions are drawn.
Źródło:
Advances in Science and Technology. Research Journal; 2017, 11, 4; 318-325
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Environmental aspects of the production and use of autoclaved aerated concrete with low density
Autorzy:
Rudchenko, Dmitry
Serdyuk, Vasyl
Powiązania:
https://bibliotekanauki.pl/articles/2091568.pdf
Data publikacji:
2022
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
greenhouse gases
energy saving
construction
autoclaved aerated concrete
low density
Opis:
The purpose of the article is to investigate the state of carbon dioxide emissions generated as a result of wall materials production and the construction industry as a whole. The paper provides a comparative analysis of housing construction in Ukraine and in some CIS countries. Against the background of the indicators of low housing availability and low relative volumes of housing construction, the issue of high energy consumption remains valid. The absolute and relative volumes of greenhouse gas emissions from economic activity of the population of Ukraine are given. The projected consequences for Ukraine from continued CO2 emissions on the same level and temperature rise are estimated. It is deemed that the most suitable wall material for countries with emerging economies is autoclaved aerated concrete (AAC); since it is a structural and thermal insulating material, it can solve the problem of housing construction. The paper shows the key priority of low energy consumption and makes emphasis on lowering the density of the produced aerated concrete, reducing mineral additives and cement production expenses.
Źródło:
Budownictwo i Architektura; 2022, 21, 1; 19--30
1899-0665
Pojawia się w:
Budownictwo i Architektura
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lightweight particleboards - manufacturing modification using a blowing agent from the group of bicarbonates
Autorzy:
Bednarczyk, Dominika
Boruszewski, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/2171742.pdf
Data publikacji:
2022
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
low density
lightweight particleboard
blowing agent
sodium bicarbonate
phenolic resin
Opis:
Lightweight particleboards - manufacturing modification using a blowing agent from the group of bicarbonates. Although the low-density particleboards have grown in popularity, due to their facilitated transportation and a lower mass in the assembled finished products, there is still certain constraints in their use caused by limited mechanical properties. These obstacles may be overcome by the mechanism of foaming the polymers that bind wood particles in the boards’ structure. The aim of this study was to determine the possibility of using sodium bicarbonate as a blowing agent of phenolic resin used for bonding wood particles in the technology of lightweight particleboards. It was found that the addition of sodium bicarbonate in the amount of 5% in relation to the dry weight of the phenolic resin significantly increase the internal bond strength of the manufactured particleboards.
łyty wiórowe o obniżonej gęstości - modyfikacja wytwarzania przy użyciu poroforu z grupy wodorowęglanów. Pomimo tego, że płyty wiórowe o obniżonej gęstości zyskują na popularności, ze względu na ułatwiony transport i niższą masę gotowych produktów, nadal istnieją pewne utrudnienia w ich zastosowaniu, spowodowane niedostatecznymi właściwościami mechanicznymi. Ograniczenia te mogą zostać zminimalizowane dzięki zastosowaniu mechanizmu spieniania żywicy wiążącej cząstki drewna w płytach wiórowych. Celem pracy było określenie możliwości zastosowania wodorowęglanu sodu jako poroforu żywicy fenolowej stosowanej do zaklejenia cząstek drewna w technologii lekkich płyt wiórowych. Stwierdzono, że dodatek wodorowęglanu sodu w ilości 5% w stosunku do suchej masy żywicy fenolowej istotnie zwiększa wytrzymałość na rozciąganie prostopadle do płaszczyzny płyty w wytworzonym materiale.
Źródło:
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology; 2022, 117; 55--62
1898-5912
Pojawia się w:
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The possibility of using bacterial cellulose in particleboard technology
Autorzy:
Wacikowski, Błażej
Michałowski, Michał
Powiązania:
https://bibliotekanauki.pl/articles/2200213.pdf
Data publikacji:
2020
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
particleboard
low density
bacterial cellulose
Kombucha
physical and mechanical properties
Opis:
The possibility of using bacterial cellulose in particleboard technology. The paper presents the results of the influence of bacterial cellulose multiplication on industrial pine particles (used in wood materials technology), and then the use of the obtained biomass in the production of particleboards with reduced density LP1 type. Based on previous preliminary studies it was determined that the most effective growth of bacterial cellulose occurs using 5% wood particles in the breeding mixture. Two series of particleboards were produced: control and containing bacterial cellulose. Selected mechanical properties of produced particleboards (modulus of rupture, modulus of elasticity and internal bond) and selected physical properties (swelling and water absorption after 2 and 24 hours of soaking in water) were determined in turn. The boards made with bacterial cellulose had lower MOR and MOE values. Swelling after 2 and 24 hours was lower for boards with bacterial cellulose. The presented tests allow to state that bacterial cellulose can be a potential raw material ingredient in the production of particleboard while meeting the minimum requirements of the technical specification for boards with reduced density LP1.
Możliwość wykorzystania celulozy bakteryjnej w technologii płyt wiórowych. W pracy przedstawiono wyniki wpływu namnażania celulozy bakteryjnej na przemysłowych wiórach sosnowych (wykorzystywanych w technologii tworzyw drzewnych), a następnie wykorzystanie otrzymanej biomasy przy produkcji płyt wiórowych o obniżonej gęstości typu LP1. Na podstawie wcześniejszych badań wstępnych określono, że najefektywniejszy przyrost celulozy bakteryjnej następuje przy zastosowaniu 5% zawartości wiórów drzewnych w mieszaninie hodowlanej. Wyprodukowano dwie serie płyt wiórowych: kontrolną oraz zawierających celulozę bakteryjną. Kolejno określono wybrane właściwości mechaniczne wytworzonych płyt wiórowych (wytrzymałość na zginanie statyczne, moduł sprężystości przy zginaniu statycznym oraz wytrzymałość na rozciąganie w kierunku prostopadłym do płaszczyzn płyty) oraz wybrane właściwości fizyczne (spęcznienie i nasiąkliwość po 2 i 24 h moczenia w wodzie). Płyty wykonane z udziałem celulozy bakteryjnej charakteryzowały się niższymi wartościami MOR oraz MOE. Spęcznienie po 2 i 24 godzinach było niższe w przypadku płyt z udziałem celulozy bakteryjnej. Przedstawione badania pozwalają stwierdzić, iż celuloza bakteryjna może stanowić potencjalny ingredient surowcowy w produkcji płyt wiórowych spełniając przy tym minimalne wymagania specyfikacji technicznej dla płyt o obniżonej gęstości typu LP1.
Źródło:
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology; 2020, 109; 16--23
1898-5912
Pojawia się w:
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of temperature on breakdown voltage of 10 MeV electron beam irradiated LDPE and HDPE
Autorzy:
Borhani, M.
Ziaie, F.
Bolorizadeh, M.
Mirjalili, G.
Powiązania:
https://bibliotekanauki.pl/articles/146157.pdf
Data publikacji:
2006
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
breakdown voltage
dielectric constant
temperature effect
electron beam
low-density polyethylene
Opis:
The paper presents measurements of the breakdown (dielectric strength) and dielectric constant of the low density polyethylene (LDPE) and high density polyethylene (HDPE) thin sheets, which were irradiated with a 10 MeV electron beam in the range of 0-470 kGy using a Rhodotron accelerator system. The tests were performed at temperatures ranging from 20°C to 110°C. Variation of the measured parameters vs. radiation absorbed dose and temperature were discussed.
Źródło:
Nukleonika; 2006, 51, 3; 179-182
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dose rate effect on LDPE cross-linking induced by electron beam irradiation
Autorzy:
Ziaie, F.
Anvari, F.
Ghaffari, M.
Borhani, M.
Powiązania:
https://bibliotekanauki.pl/articles/148862.pdf
Data publikacji:
2005
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
dose rate
electron beam
low-density polyethylene
cross-linking
chain scission
Opis:
In this project, the radiation induced cross-linking in low-density polyethylene (LDPE) samples irradiated with the different dose rates of 5 MeV electron beam in the dose range of 20 up to 200 kGy were investigated and compared. The dose rate values were ranged from 13 to 300 kGy/min. The cross-linking of the samples were studied on the basis of gel content measurement and a hot set test. The yield of gel content showed slight increases with decreasing dose rate values. The same results were more clearly observed using the hot set test. It was concluded that, to irradiate the product based on LDPE, any variation in electron beam current causes different dose rates which, in turn, affect the absorbed dose value in materials.
Źródło:
Nukleonika; 2005, 50, 3; 125-127
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The reactions of hypochlorous acid, the reactive oxygen species produced by myeloperoxidase, with lipids.
Autorzy:
Spickett, Corinne
Jerlich, Andreas
Panasenko, Oleg
Arnhold, Juergen
Pitt, Andrew
Stelmaszyńska, Teresa
Schaur, R.
Powiązania:
https://bibliotekanauki.pl/articles/1044206.pdf
Data publikacji:
2000
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
lipid chlorohydrins
lipids
unsaturated fatty acids
hypochlorous acid
lipid peroxidation
low density lipoprotein
Opis:
Myeloperoxidase (MPO), an abundant enzyme in phagocytes, has been implicated in the pathogenesis of various inflammatory diseases including atherosclerosis. The major oxidant produced by MPO, hypochlorous acid (HOCl), is able to modify a great variety of biomolecules by chlorination and/or oxidation. In this paper the reactions of lipids (preferentially unsaturated fatty acids and cholesterol) with either reagent HOCl or HOCl generated by the MPO-hydrogen peroxide-chloride system are reviewed. One of the major issues has been whether the reaction of HOCl with lipids of low density lipoprotein (LDL) yields predominantly chlorohydrins or lipid hydroperoxides. Electrospray mass spectrometry provided direct evidence that chlorohydrins rather than peroxides are the major products of HOCl- or MPO-treated LDL phosphatidylcholines. Nevertheless lipid peroxidation is a possible alternative reaction of HOCl with polyunsaturated fatty acids if an additional radical source such as pre-formed lipid hydroperoxides is available. In phospholipids carrying a primary amino group such as phosphatidylethanolamine chloramines are the preferred products compared to chlorohydrins. Cholesterol can be converted by HOCl to great variety of oxysterols besides three isomers of chlorohydrins. For the situation in vivo it appears that the type of reaction occurring between HOCl and lipids would very much depend on the circumstances, e.g. the pH and the presence of radical initiators. The biological effects of lipid chlorohydrins are not yet well understood. It has been shown that chlorohydrins of both unsaturated fatty acids as well as of cholesterol may cause lysis of target cells, possibly by disruption of membrane structures.
Źródło:
Acta Biochimica Polonica; 2000, 47, 4; 889-899
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of post-production materials on lightweight wood fiberboard parameters
Autorzy:
Szuta, Jarosław
Fuczek, Dorota
Szutkowski, Krystian
Powiązania:
https://bibliotekanauki.pl/articles/2201357.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Technologii Drewna
Tematy:
insulations fibreboard
post-production materials
low density fibreboard
wood fibres
LDF
wood fibreboards
Opis:
The aim of this study was to produce a very low-density insulation wood fibreboard, in dry technology, with the use of post-production fibres. During the tests, different amounts of post-production fibres, coming from various stages of processing such as grinding, edges cutting, cutting to the required board size, milling and disqualification of faulty boards, were added to lightweight fibreboard. The amount of possible added post-production wood fibres strongly depends on the characteristic of the fibres and particles size distribution. The parameters of the lightweight board, the most influenced by the dimensions of the fibres used, are mainly thermal conductivity and compressive strength.
Źródło:
Drewno. Prace Naukowe. Doniesienia. Komunikaty; 2022, 65, 210
1644-3985
Pojawia się w:
Drewno. Prace Naukowe. Doniesienia. Komunikaty
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Low Density Parity Check Codes Constructed from Hankel Matrices
Autorzy:
Tehami, M. A.
Djebbari, A.
Powiązania:
https://bibliotekanauki.pl/articles/958065.pdf
Data publikacji:
2018
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
dual diagonal matrix
error correcting codes
girth
Hankel matrix
low density parity check code
Opis:
In this paper, a new technique for constructing low density parity check codes based on the Hankel matrix and circulant permutation matrices is proposed. The new codes are exempt of any cycle of length 4. To ensure that parity check bits can be recursively calculated with linear computational complexity, a dual-diagonal structure is applied to the parity check matrices of those codes. The proposed codes provide a very low encoding complexity and reduce the stored memory of the matrix H in which this matrix can be easily implemented comparing to others codes used in channel coding. The new LDPC codes are compared, by simulation, with uncoded bi-phase shift keying (BPSK). The result shows that the proposed codes perform very well over additive white Gaussian noise (AWGN) channels.
Źródło:
Journal of Telecommunications and Information Technology; 2018, 3; 37-41
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of diabetes-associated lipoproteins on oxygen consumption and mitochondrial enzymes in porcine aortic endothelial cells
Autorzy:
Xie, Xueping
Chowdhury, Subir
Sangle, Ganesh
Shen, Garry
Powiązania:
https://bibliotekanauki.pl/articles/1040288.pdf
Data publikacji:
2010
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
mitochondrial membrane potential
mitochondrial oxygen
respiration chain
vascular endothelial cells
consumption
low density lipoprotein
Opis:
Impairments in mitochondrial function have been proposed to play an important role in the pathogenesis of diabetes. Atherosclerotic coronary artery disease (CAD) is the leading cause of mortality in diabetic patients. Mitochondrial dysfunction and increased production of reactive oxygen species (ROS) are associated with diabetes and CAD. Elevated levels of glycated low density lipoproteins (glyLDL) and oxidized LDL (oxLDL) were detected in patients with diabetes. Our previous studies demonstrated that oxLDL and glyLDL increased the generation of ROS and altered the activities of antioxidant enzymes in vascular endothelial cells (EC). The present study examined the effects of glyLDL and oxLDL on mitochondrial respiration, membrane potential and the activities and proteins of key enzymes in mitochondrial electron transport chain (mETC) in cultured porcine aortic EC (PAEC). The results demonstrated that glyLDL or oxLDL significantly reduced oxygen consumption in Complex I, II/III and IV of mETC in PAEC compared to LDL or vehicle control using oxygraphy. Incubation with glyLDL or oxLDL significantly reduced mitochondrial membrane potential, the activities of mitochondrial ETC enzymes - NADH dehydrogenase (Complex I), succinate cytochrome c reductase (Complex II + III), ubiquinol cytochrome c reductase (Complex III), and cytochrome c oxidase (Complex IV) in PAEC compared to LDL or control. Treatment with oxLDL or glyLDL reduced the abundance of subunits of Complex I, ND1 and ND6 in PAEC. However, the effects of oxLDL on mitochondrial activity and proteins were not significantly different from glyLDL. The findings suggest that the glyLDL or oxLDL impairs mitochondrial respiration, as a result from the reduction of the abundance of several key enzymes in mitochondria of vascular EC, which potentially may lead to oxidative stress in vascular EC, and the development of diabetic vascular complications.
Źródło:
Acta Biochimica Polonica; 2010, 57, 4; 393-398
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characteristic of low-density polyethylene reinforcement with nano/micro particles of carbon black: a comparative study
Autorzy:
Sabr, O.H.
Al-Mutairi, N.H.
Layla, A.Y.
Powiązania:
https://bibliotekanauki.pl/articles/2175763.pdf
Data publikacji:
2021
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
low-density polyethylene
carbon black
thermal conductivity
nanocomposite
SEM
polietylen wysokociśnieniowy
sadza
przewodność cieplna
nanokompozyt
Opis:
Purpose: Low density polyethylene is commonly used polymer in the industry because of its unique structure and excellent overall performance. LDPE, is relatively low mechanical properties and thermal stability can sometimes limit its application in industry. Therefore, the development of particulate reinforced polymer composites is one of the highly promising methodologies in the area of next generation engineering products. Design/methodology/approach: Nano and Micro composite from low density polyethylene LDPE reinforced with different weight fraction of carbon black particles (CB) (2, 4 and 8)% prepared by first dispersion Nano and Micro carbon black particles CB in solvent and then mixing manually with low density polyethylene LDPE pellet and blended by twin-screw extruder, the current research study the mechanical properties (tensile strength, elastic modulus,and hardness), FTIR, DSC,and thermal conductivity of prepared nano and micro composites using two methodes and the morphological properties of nano-micro composites. Findings: The tensile strength of the LDPE/CB nano and micro composites improved at 2% and 4%, respectively, and decreasing at 8%, addition of carbon black nanoparticles led to increase the tensile strength of pure low-density polyethylene from 13.536 MPa to 19.71 MPa, and then dropping to 11.03 MPa at 8% percent,while the elastic modulus of LDPE/ CB nano and miro composites shows an improvement with all percentages of CB. The results show that the mechanical properties were improved by the addition carbon black nanoparticles more than addition micro- carbon black . FTIR show that physical interaction between LDPE and carbon black. The thermal conductivity improvement from 0.33 w/m.k for pur LDPE to 0.62234 w/m.k at 2% CB microparticle content and the reduced to 0.18645 w/m.k and 0.34063 w/m.k at (4 and 8)% micro-CB respectively , The thermal conductivity of LDPE-CB nano-composites is low in general than that the LDPE-CB microcomposite. DSC result show improvement in crystallization temperature Tc, melting temperature and degree of crystallization with addition nano and micro carbon black. Morever, SEM images revealed to uniform distribution and good bonding between LDPE and CB at low percentages and the precence of some agglomeration at high CB content. Research limitations/implications: This research studied the characteristics of both nano and micro composite materials prepared by two steps: mixing CB particles with solvent and then prepared by twin extruder which can be used packaging material, but the main limitation was the uniform distribution of nano and micro CB particles within the LDPE matrix. In a further study, prepare a blend from LDPE with other materials and improve the degradation of the blend that used in packaging application. Originality/value: LDPE with nanocomposites are of great interest because of their thermal stability, increased mechanical strength, stiffness, and low gas permeability, among other properties that have made them ideal for applications in the packaging and automotive industries. LDPE reinforcements nano-sized carbon black can have better mechanical and thermal properties than micron, resulting in less material being needed for a given application at a lower cost.
Źródło:
Archives of Materials Science and Engineering; 2021, 110, 2; 49--58
1897-2764
Pojawia się w:
Archives of Materials Science and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Właściwości lepkosprężyste polietylenu małej gęstości oznaczane podczas ściskania
The viscoelastic properties of low density polyethylene determined during compression
Autorzy:
Głogowska, K.
Sikora, J.W.
Powiązania:
https://bibliotekanauki.pl/articles/277994.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Inżynierii Materiałów Polimerowych i Barwników
Tematy:
ściskanie
wytłaczanie
polietylen małej gęstości
natychmiastowy powrót poodkształceniowy
compression
extrusion
low-density polyethylene
immediate elastic recovery
Opis:
Statyczna próba ściskania, obok statycznej próby rozciągania jest jedną z podstawowych prób stosowanych do określenia właściwości mechanicznych materiałów. Właściwości wytrzymałościowe tworzyw termoplastycznych zależą od wielu czynników: sił wiązań chemicznych, sił oddziaływań międzycząsteczkowych, prędkości obciążania, czasu działania obciążenia, właściwości lepkosprężystych itp. Wyniki badań wytrzymałości na ściskanie są szczególnie ważne podczas doboru tworzywa na elementy konstrukcyjne maszyn i do zastosowań w budownictwie, gdzie współpracują one z materiałami o odmiennych często właściwościach. W pracy przedstawiono wyniki badań powrotu poodkształceniowego po ściskaniu próbek z polietylenu małej gęstości (PE-LD) otrzymanych w procesie wytłaczania konwencjonalnego i autotermicznego przy różnych prędkościach obrotowych ślimaka. W pracy przedstawiono wyniki pomiarów podstawowych wielkości występujących podczas próby ściskania tworzyw termoplastycznych tj. bezwzględne skrócenie próbki (ΔL); natychmiastowy powrót poodkształceniowy (σ); opóźniony powrót poodkształceniowy (λ) oraz odkształcenie ściskające (ε). Zaprezentowano zależność zmiany długości odcinka pomiarowego (h2) kształtki od czasu po usunięciu z maszyny wytrzymałościowej. Artykuł zakończono stosownymi wnioskami.
The static compression test, in addition to the static tensile test, is one of the basic tests used to determine the mechanical properties of materials. The strength properties of thermoplastics depend on many factors: chemical bonding forces, intermolecular forces, the speed of loading, the time of loading effect, viscoelastic properties, etc. The results of the compressive strength are especially important for the selection of materials for construction elements of machines and for the use in construction industry, where they cooperate with materials which often have different properties. The work presents the results oftesting elastic recovery during the compression of samples from low-density polyethylene (PE-LD), obtained in the conventional and autothermal extrusion process and with different rotational speeds of the screw. The work presents the results of basic measurements of parameters occurring during the compression test of thermoplastics, i.e. free absolute strain (ΔL); immediate elastic recovery (σ); delayed elastic recovery (λ) and complete elastic recovery (ε). The dependence of change in the length of the measuring section (h2) of the moulder from the time after removal from the testing machine was presented. The paper was concluded with appropriate conclusions.
Źródło:
Przetwórstwo Tworzyw; 2015, T. 21, Nr 4 (166), 4 (166); 324-328
1429-0472
Pojawia się w:
Przetwórstwo Tworzyw
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Epidemic Determinats in Housing
Epidemiczne determinanty w mieszkalnictwie
Autorzy:
Wojtkun, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/2034219.pdf
Data publikacji:
2021
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
architectural archetype
low density housing
epidemic threat
informal distances
archetyp architektoniczny
dystanse nieformalne
mieszkalnictwo
zagrożenie epidemiczne
Opis:
Multi-family housing of high intensity may pose a significant threat to the health and life of residents during epidemics. Excessive concentration of a larger population in a confined area and the long time people spent together during a day create favorable conditions for the spread of pathogens. Complete elimination of the threat in such areas does not seem possible, and the same applies to the full identification of routes pathogens use to spread. The aim of the study is to indicate architectural solutions, with particular emphasis on archetypes, that can reduce the risk to health and life of people in residential areas. In this case, the study uses observation, analysis, and logical construction methods. The epidemic and its consequences highlighted the need to abandon trends that increase the compactness of cities and define residents’ movement patterns.
Wszystko wskazuje na to, że sytuacja epidemiczna stała się determinantą również w mieszkalnictwie. Mianowicie, w miejsce bliżej niedookreślonego dyskomfortu psychicznego i somatycznego skutkującego w dłuższym okresie czasu pojawiło się bezpośrednie zagrożenie zdrowia i życia. To ostatnie wyniknęło przede wszystkim z nadmiernej bliskości w miejscu zamieszkania. Wiele wskazuje na to, że w dobie pandemii istotne zagrożenie dla zdrowia i życia mieszkańców miast stanowi mieszkalnictwo wielorodzinne wysokiej intensywności. Nadmierna koncentracja ludności na małym obszarze oraz długi w ciągu doby czas wspólnego tam przebywania stwarzają sprzyjające warunki do rozprzestrzeniania się patogenów. Całkowite wyeliminowanie zagrożenia w tym zakresie nie wydaje się możliwe podobnie jak rozpoznanie sposobu rozprzestrzeniania się czynników chorobotwórczych. Celem pracy jest wskazanie rozwiązań architektonicznych mogących ograniczyć zagrożenie zdrowia i życia na obszarze mieszkaniowym ze szczególnym uwzględnieniem archetypów.
Źródło:
Przestrzeń i Forma; 2021, 47; 9-28
1895-3247
2391-7725
Pojawia się w:
Przestrzeń i Forma
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vascular smooth muscle cells in cultures on low density polyethylene modified with plasma discharge and biofunctionalization
Autorzy:
Parizek, M.
Kasalkova, N.
Bacakova, L.
Kolarova, K.
Lisa, V.
Svorcik, V.
Powiązania:
https://bibliotekanauki.pl/articles/285087.pdf
Data publikacji:
2009
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
Ar plasma discharge
biomaterials
low-density polyethylene
cell adhesion
cell proliferation
grafting
tissue engineering
vascular smooth muscle cells
Opis:
Low density polyethylene (LDPE) was modified by an Ar plasma discharge and then grafted with glycine (Gly), bovine serum albumin (BSA) or polyethylene glykol (PEG). Some plasma-treated samples and samples grafted with BSA were exposed to a suspension of colloidal carbon particles (C, BSA+C). Pristine LDPE and tissue culture polystyrene dishes (PSC) were used as control samples. The materials were seeded with rat aortic smooth muscle cells and incubated in a medium DMEM with 10% of fetal bovine serum. On day 1 after seeding, the cells on LDPE modified with plasma only, Gly, BSA and BSA+C adhered in similar numbers as on PSC, while the values on non-modified and PEG-modified samples were significantly lower. On day 5, the highest cell numbers were found again on LDPE with Gly, BSA and BSA+C. On day 7, the highest number of cells was found on LDPE modified only with plasma. The latter cells also dis-played the largest cell spreading area. The increased cell colonization was probably due to the formation of oxygen-containing chemical functional groups after plasma irradiation, and also due to positive effects of grafted Gly, BSA and BSA in combination with colloidal C particles.
Źródło:
Engineering of Biomaterials; 2009, 12, no. 89-91; 25-28
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prostaglandins and arterial wall lipid metabolism - in vitro, ex-vivo and in vivo radioisotopic studies
Autorzy:
Sinzinger, H
Rogatti, W.
Powiązania:
https://bibliotekanauki.pl/articles/69328.pdf
Data publikacji:
1994
Wydawca:
Polskie Towarzystwo Fizjologiczne
Tematy:
metabolism
prostaglandin
lipid
calcium antagonist
in vivo
lipid metabolism
radioisotopic study
in vitro
hypercholesterolemia
low density lipoprotein
atherosclerosis
Źródło:
Journal of Physiology and Pharmacology; 1994, 45, 1
0867-5910
Pojawia się w:
Journal of Physiology and Pharmacology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimizing the Bit-flipping Method for Decoding Low-density Parity-check Codes in Wireless Networks by Using the Artificial Spider Algorithm
Autorzy:
Ghaffoori, Ali Jasim
Abdul-Adheem, Wameedh Riyadh
Powiązania:
https://bibliotekanauki.pl/articles/2055251.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
low-density parity-check
LDPC
hard-decision Bit-Flipping
BF
particle swarm optimization
PSO
artificial spider algorithm
ASA
Opis:
In this paper, the performance of Low-Density Parity-Check (LDPC) codes is improved, which leads to reduce the complexity of hard-decision Bit-Flipping (BF) decoding by utilizing the Artificial Spider Algorithm (ASA). The ASA is used to solve the optimization problem of decoding thresholds. Two decoding thresholds are used to flip multiple bits in each round of iteration to reduce the probability of errors and accelerate decoding convergence speed while improving decoding performance. These errors occur every time the bits are flipped. Then, the BF algorithm with a low-complexity optimizer only requires real number operations before iteration and logical operations in each iteration. The ASA is better than the optimized decoding scheme that uses the Particle Swarm Optimization (PSO) algorithm. The proposed scheme can improve the performance of wireless network applications with good proficiency and results. Simulation results show that the ASA-based algorithm for solving highly nonlinear unconstrained problems exhibits fast decoding convergence speed and excellent decoding performance. Thus, it is suitable for applications in broadband wireless networks.
Źródło:
International Journal of Electronics and Telecommunications; 2022, 68, 1; 109--114
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improved adhesion and growth of vascular smooth muscle cells in cultures on polyethylene modified by plasma discharge
Autorzy:
Parizek, M.
Kasalkova, N.
Bacakova, L.
Kolarova, K.
Lisa, V.
Svorcik, V.
Powiązania:
https://bibliotekanauki.pl/articles/284295.pdf
Data publikacji:
2007
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
biomateriały
inżynieria tkankowa
Ar plasma discharge
high density and low density polyethylene
cell adhesion
cell proliferation
vascular smooth muscle cells
biomaterials
tissue engineering
Opis:
The attractiveness of synthetic polymers for cell colonization can be affected by physical and chemical modification of the polymer surface. In this study, high density polyethylene (HDPE, m.w. 0.952g/cm3) and low density polyethylene (LDPE, m.w. 0.922g/cm3) were modified by an Ar plasma discharge using Balzers SCD 050 device (exposure time 10, 50, 150 and 400 seconds, discharge power 1.7W). The material was then seeded with rat aortic smooth muscle cells (RASMC; passages 8 to 9, 17 000 cells/cm3) and incubated in a DMEM medium with 10% of fetal calf serum. On day 1 after seeding, the number of initially adhered cells was significantly higher on all modified HDPE and LDPE samples. On day 2, this difference persisted in HDPE, whereas in LDPE only the values on the samples modified by 150 and 400 seconds were significantly higher. On the 5th and 7th day, there were no significant differences in cell number among all LDPE samples. However, on the HDPE foils, significant differences were still apparent on the samples modified for 400 seconds. The cell spreading areas measured on day 1 after seeding were significantly larger on all modified LDPE samples, and, on day 2, on the HDPE samples exposed for 150s. The increased cell colonization was probably due to the formation of oxygen-containing chemical functional groups in the polymer. These results suggest that the responsiveness of the cell to the changes in physiochemical surface properties was more pronounced in HDPE than in LDPE. On both types of polyethylene, the most appropriate exposure time for the enhancement of cell adhesion and growth seemed to be 150 and 400 seconds.
Źródło:
Engineering of Biomaterials; 2007, 10, no. 67-68; 1-4
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The kinetic degradation of LDPE films subjected to aggressive environments
Kinetyczna degradacja folii LDPE poddanych działaniu agresywnych środowisk
Autorzy:
Kashi, Imad
Zeghouan, Ouahida
Moussaceb, Karim
Powiązania:
https://bibliotekanauki.pl/articles/2200482.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
Tematy:
low-density polyethylene
modeling
kinetic degradation
half-life time
thermo-oxidative
polietylen małej gęstości
modelowanie
kinetyczna degradacja
okres półtrwania
termoutlenianie
Opis:
The effect of natural and thermo-oxidative aging on the structure and physicochemical properties of LDPE films stabilized with hindered amine light stabilizers (HALS) was investigated. Based on multiple linear regression analysis (MLRA) mathematical models to predict the lifetime of the LDPE were developed. Four statistical criteria were used to evaluate the developed models: residual variance, coefficient of determination, Student’s test and the Fisher-Snedecor test. The half-life times predicted by the mathematical models were found to be statistically significant (p < 0.05).
Zbadano wpływ starzenia w warunkach naturalnych i starzenia termooksydacyjnego na strukturę i właściwości fizykochemiczne folii LDPE stabilizowanych aminowymi fotostabilizatorami z zawadą przestrzenną (HALS). W oparciu o wielokrotną analizę regresji liniowej (MLRA) opracowano modele matematyczne do przewidywania czasu życia folii LDPE. Do oceny opracowanych modeli stosowano cztery kryteria statystyczne: wariancję szczątkową, współczynnik determinacji, test Studenta i test Fishera-Snedecora. Stwierdzono, że okresy półtrwania przewidywane przez modele matematyczne są istotne statystycznie (p < 0,05).
Źródło:
Polimery; 2022, 67, 6; 250--255
0032-2725
Pojawia się w:
Polimery
Dostawca treści:
Biblioteka Nauki
Artykuł
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