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EN
The paper presents data on the effect of storage duration and UV-C stimulation mode of potato tubers and soaking of potato strips in water on strip density. The study was conducted on potato tubers of the Innovator variety cut into strips with a cross-section of 10 x 10 mm and 60 mm long. Strips were cut along the longitudinal tuber axis set between proximal and distal tuber end. The studies were conducted on tubers at two time points: 1. after 3-month storage and 2. after 9-month storage. Potato tubers were stimulated by UV-C using the following modes: 1 and 3 – irradiation on one tuber side for 30 min, 2 and 4 – irradiation on opposite tuber sides for 15 min each, 0 – control group (not irradiated). Tubers irradiated according to mode 1 and 2 were stimulated 2 days before processing whereas according to modes 3 and 4 before storage. Strips were soaked in water (1) at a temperature of 20oC for 15 min and (2) at a temperature of 40oC for 20 min. In addition, the studies included the strips blanched at a temperature of 90oC for 2 min and the control group comprising unsoaked strips. The storage and laboratory experiments were conducted in 2016-2017. Strip density was statistically significantly dependent on storage duration, stimulation and soaking conditions. Prolongation of storage and UV-C stimulation of tubers prior to storage (in both variants) and prior to processing (longer irradiation on one side of the tuber) increased the density of the strips. On the other hand, raising the soaking time from 15 min to 20 min and water temperature from 20oC to 40oC reduced strip density.
PL
W pracy przedstawiono wpływu terminu przechowywania i napromieniania UV-C bulw oraz zanurzenia słupków ziemniaczanych w wodzie na gęstość półproduktów na frytki. Jako materiał do badań wykorzystano bulwy ziemniaka odmiany Innovator. Badano obiekty w kształcie słupków o przekroju 10x10 mm i długości 60 mm. Słupki wycinano wzdłuż najdłuższej osi bulw, wyznaczonej pomiędzy częścią wierzchołkową i pępkową. Badania wykonano na bulwach w dwóch terminach: 1 - po 3 miesiącach i 2 - po 9 miesiącach przechowywania. W celu naświetlenia bulw ziemniaka stosowano następujące parametry stymulacji UV-C: 1, 3 - naświetlanie 30 min z jednej strony bulwy, 2, 4 - naświetlanie po 15 min z dwóch przeciwnych stron bulwy, 0 - próba kontrolna (bez naświetlania). Stymulację bulw w sposób 1, 2 prowadzono na dwa dni przed przetwarzaniem, a naświetlanie 3, 4 przed przechowywaniem. Proces sorpcji realizowano poprzez zanurzanie badanych obiektów w wodzie o temperaturze: 1 - 20oC w czasie 15min i 2 - 40oC w czasie 20min. Do badań przyjęto ponadto słupki poddane blanszowaniu 3 - 90oC i 2 min oraz próbę kontrolną 0 - bez zanurzania. Doświadczenia przechowalnicze i laboratoryjne realizowano w latach 2016-2017. Na gęstość s łupków statystycznie istotny wpływ miały termin przechowywania, stymulacja i warunki zanurzenia półproduktów. Wzrost czasu przechowywania oraz zastosowanie stymulacji UV-C bulw przed przechowywaniem (w obu przyjętych wariantach) i przed przetwarzaniem, w wersji naświetlani dłuższym czasem z jednej strony bulw, skutkowało zwiększeniem gęstości półproduktów. Wzrost czasu zanurzenia półproduktów z15 do 20min i temperatury wody z 20 do 40 oC powodował obniżenie gęstość półproduktów.
2
Content available remote Ciecz robocza do rekonstrukcji odwiertów o obniżonym ciśnieniu złożowym
PL
Wytworzenie przeciwciśnienia na złoże oraz zapobieganie uszkodzeniu strefy przyodwiertowej to podstawowe zadanie cieczy roboczej o odpowiedniej gęstości zatłoczonej do odwiertu celem przeprowadzenia wymaganego zakresu prac rekonstrukcyjnych. Skład i właściwości technologiczne cieczy roboczej powinny być ustalone na podstawie aktualnie występujących w danym odwiercie lub horyzoncie produktywnym warunków geologiczno-złożowych. Wykorzystywane w warunkach złożowych ciecze do rekonstrukcji odwiertów to solanki bez fazy stałej oraz sporządzane na osnowie solanek z dodatkiem m.in. polimeru i blokatora. Są one stosowane w odwiertach, w których dla zrównoważenia gradientu ciśnienia złożowego 0,00981–0,023 MPa/m wymagane jest użycie cieczy o gęstości 1,03– 2,3 kg/dm3 . Natomiast w złożach, w których gradient ciśnienia złożowego wynosi poniżej 0,00981 MPa/m, powinny być wykorzystywane specjalne ciecze o gęstości ≤1,0 kg/dm3 . Wstępne badania laboratoryjne przeprowadzone w INiG – PIB wskazały kierunek doboru środków stanowiących osnowę takich cieczy i wpływ wybranych środków na właściwości technologiczne otrzymywanych cieczy roboczych o gęstości ≤1,0 kg/dm3 . Jak wykazały badania, mogą to być związki syntetyczne spełniające rolę oleju, które nie zawierają węglowodorów aromatycznych szkodliwych dla środowiska. Do generacji tych związków zaliczane są estry, polialfaolefiny, etery i acetale, a najszersze zastosowanie w technologii cieczy wiertnicznych zyskały estry oraz związki chemiczne z grupy olefin. Przedmiotem badań laboratoryjnych nad opracowaniem cieczy roboczej do złóż o obniżonym ciśnieniu złożowym był syntetyczny związek chemiczny pełniący rolę oleju, tj. estry metylowe kwasów tłuszczowych oleju rzepakowego. Przy użyciu tego związku podjęte zostały próby laboratoryjne sporządzenia cieczy stanowiącej dwie fazy, tj. olejową i wodną. Badania, które wykonano dla warunków geologiczno-złożowych występujących na zapadlisku przedkarpackim, obejmowały ustalenie składu fazy olejowej i wodnej, sposób sporządzania cieczy, określenie jej właściwości technologicznych i inhibitujących oraz wpływu na środowisko.
EN
Creation of back pressure on the deposit and prevention of damage to the wellbore zone is the basic task of the workover fluid of appropriate density, pumped into the well to carry out the required scope of reconstruction work. The composition and technological properties of the workover fluid should be determined based on the current geological and reservoir conditions in the given well or pay zone. Well reconstruction liquids used in reservoir conditions are brines without a solid phase and prepared based on brine with the addition of among others a polymer and a blocker. They are used in wells where a fluid density of 1.03–2.3 kg/dm3 is required to balance the reservoir pressure gradient 0.00981–0.023 MPa/m. However, in deposits where the gradient of reservoir pressure is below 0.00981 MPa/m, special liquids with a density of ≤1.0 kg/dm3 should be used. Preliminary laboratory tests carried out at INiG – PIB showed the direction of selection of agents constituting the base of such fluids and the impact of these agents on the technological properties of the obtained workover fluids with a density of ≤1.0 kg/dm3 . Research has shown that these can be synthetic compounds that act as oil and do not contain aromatic hydrocarbons that are harmful to the environment. This group of compounds includes esters, polyalphaolefins, ethers and acetals, and esters and chemical compounds from the olefin group have gained the widest use in drilling fluid technology. The subject of laboratory research on the development of workover fluids for deposits with reduced reservoir pressure was a synthetic chemical compound acting as an oil, i.e. fatty acid methyl esters rapeseed oil. Using this compound, laboratory tests were made to prepare fluids that constitute two phases, i.e. oil and water. The tests that were carried out for geological and reservoir conditions occurring in the Carpathian Foredeep wells included determining the composition of the oil and water phase, the method of preparation of these fluids, determining their technological and inhibitory properties as well as the impact on the environment.
EN
For designing a new energetic material with good performance, a knowledge of its density is required. In this study, the relationship between the densities of energetic co-crystals and their molecular structures was examined through a quantitative structure-property relationship (QSPR) method. The methodology of this research provides a new model which can relate the density of an energetic co-crystal to several molecular structural descriptors, which are calculated by Dragon software. It is indicated that the density of a co-crystal is a function of sp, OB, DU, nAT, as well as several non-additive structural parameters. The new recommended correlation was derived on the basis of the experimental densities of 50 co-crystals with various structures as a training set. The R2 or determination coefficient of the derived correlation was 0.937. This correlation provided a suitable estimate for a further 12 energetic co-crystals as a test set. Meanwhile, the predictive ability of the correlation was investigated through a cross validation method. Moreover, the new model has more reliability and performance for predicting the densities of energetic co-crystals compared to a previous one which was based on an artificial neural network approach. As a matter of fact, designing novel energetic co-crystals is possible by utilising the proposed method.
PL
W artykule przedstawiono wyniki badań podciągania kapilarnego, które przeprowadzono na próbkach betonu komórkowego czterech klas gęstości: 400, 500, 600 oraz 700 pochodzących z tej samej wytwórni. Największą dynamiką procesu podciągania kapilarnego charakteryzowały się próbki betonu komórkowego klasy gęstości 400. Relacje między średnimi wartościami współczynników sorpcji A wyglądały następująco: A400/A500 = 3,92/2,48 = 1,58; A400/A600 = 3,92/2,26 = 1,73; A400/A700 = 3,92/2,36 = 1,66.
EN
The article presents the results of research on the capillarity suction process, which were carried out on four density class of autoclaved aerated concrete specimens from the same manufacturer: 400, 500, 600 and 700. The highest dynamics of the process of capillarity suction was observed in autoclaved aerated concrete specimens of density class 400. Relationships concerning the resultant values of water sorption coefficients A were respectively: A400/A500 = 3,92/2,48 = 1,58; A400/A600 = 3,92/2,26 = 1,73; A400/A700 = 3,92/2,36 = 1,66.
EN
The aim of study was to determine the influence of sonication and freezing on the kinetic of the microwave-vacuum drying, energy consumption and physical properties of whole cranberries as well as evaluate the applicability of sonication instead of freezing in order to change their physical properties and the drying kinetic of whole cranberries. Microwave-vacuum drying of whole cranberries with/without initial treatments took from 12 ± 1 to 14.5 ± 0.5 minutes. All of treatments did not significantly shorten the drying time of cranberries. However, they increased SMER values even by 31%. Despite of cryogenic freezing, all of treatments significantly increased the values of Dew. Sonication combined with drying allowed to obtain dried berries characterized by the lowest cohesiveness (0.19±0.02), springiness (0.62±0.02) and chewiness (3.4±0.8 N), while cryogenic freezing combined with drying allowed to obtain dried fruits characterized by highest springiness (0.75±0.03) and low chewiness (3.3±0.5 N). The highest lightness (32.2±0.7), redness (32.6±0.8), and yellowness (11.1±0.7) were found for fruits subjected to initial convective freezing before drying. The efficiency of sonication in color change was comparable to cryogenic freezing and much lower than convective freezing. All of initial treatments increased such thermal properties of dried cranberries as thermal conductivity and thermal diffusivity.
PL
W pracy podjęto próbę zastąpienia mąki pszennej mąkami bezglutenowymi (z ciecierzycy, jaglaną i z ryżu brązowego) w biszkoptach wypiekanych w temperaturach 160 i 180°C. Badano cechy sensoryczne oraz instrumentalnie barwę i teksturę biszkoptów. Na podstawie przeprowadzonej oceny sensorycznej, przy uwzględnieniu cech takich jak: wygląd zewnętrzny, smak, zapach, struktura i tekstura oraz ogólna pożądalność, najbardziej atrakcyjny okazał się biszkopt z mąki z ciecierzycy, niezależnie od temperatury wypieku. Najwyższą ocenę za smak uzyskał biszkopt z mąki z ryżu brązowego. Biszkopt z mąki jaglanej otrzymał najniższe oceny pod względem każdej analizowanej cechy. Rodzaj mąki istotnie wpływał na jasność i nasycenie barwy biszkoptów. Zawartość wody oraz gęstość pozorna biszkoptów nie zależały od rodzaju mąki i zastosowanej temperatury wypieku, różna była tylko aktywność wody. Biszkopty z substytutami mąki pszennej charakteryzowały się większą porowatością i mniejszą twardością w porównaniu z wzorcem.
EN
In the study, the attempt was undertasken to replace wheat flour with with gluten-free flours (from chickpeas, millet and brown rice) in sponge cakes, baked at 160 and 180°C. Sensory and instrumental qualities of color and texture of sponge cakes were evaluated. On the basis of sensory evaluation carried out, taking into account the examined characteristics (appearance, structure and texture, taste, smell and general desirability), the chickpeas flour sponge cake trned out to be the most attractive, regardless of the baking temperature. In terms of taste, the sponge cake produced from brown rice flour acquired the highest notes. The millet sponge cake obtained the lowest marks in terms of each analyzed attributes. A significant influence of the type of flour was observed in the analysis of the brightness and color saturation of sponge cake. Flour type and baking temperature did not a significant influence on the water content and apparent density of sponge cake, only the water activity of final products varied. Gluten-free sponge cakes were characterized by higher porosity and lower hardness in comparison to the template.
7
Content available Drewno księżycowe jako materiał konstrukcyjny
PL
W pracy przedstawiono koncepcję drewna księżycowego i najważniejsze jego zasady. Przedstawiono również badania potwierdzające fenomen wpływu faz Księżyca na właściwości drewna księżycowego, od fazy kiełkowania do jego cech fizykomechanicznych, tj. na gęstość czy wytrzymałość.
EN
Mg0.95Ni0.05Ti0.98Zr0.02O3 and CaTiO3 were prepared separately using solid state reaction method. The effect of CaTiO3 addition on the microwave dielectric properties of Mg0.95Ni0.05Ti0.98Zr0.02O3was investigated to get low loss and temperature stable ceramics in (1 – x)Mg0.95Ni0.05Ti0.98Zr0.02O3 and CaTiO3 series. Mg0.95Ni0.05Ti0.98Zr0.02O3formed as the major phase along with Mg0.95Ni0.05Ti2O5 phase that formed as minor secondary phase for the composition with x = 0. Microwave dielectric properties ∈r ~ 17.1, Qufo of 195,855 GHz and τf of –46.3 ppm/°C were obtained for the composition with x = 0. The positive τf value of CaTiO3, tuned the τf value of Mg0.95Ni0.05Ti0.98Zr0.02O3through zero and ∈r ~ 28.4, Qufo ~ 108,775 GHz and τf ~ 3.1 ppm/°C were attained for x = 0.15 in this study. This composition is the best choice for high frequency applications.
EN
The development of mangrove ecosystem has a significant impact on fishery resources, such as gastropod. This research aimed at studying the community structure of mangrove forest in Mojo village, to identifying and analyzing the composition and diversity of gastropod, and investigating the effect of mangrove community on the abundance and gastropod. The research was conducted in Mojo Village, Ulujami District, Pemalang Region from November to December 2017. Identification of species and density was conducted on mangrove species by means of line and plot transects, while the gastropod was sampled from the field then identified in the laboratory. Three sampling stations were occupied in the data collection. The data analysis was conducted for diversity indices, including heterogeneity and evenness both for mangrove and gastropod. Statistical data analysis was conducted by regression to analyze the effect of mangrove density on the abundance of gastropod. The result showed that only three mangrove species were found in Mojo village, including Rhizophora mucronata, Avicennia marina and A. officinalis. Eight gastropod species were identified from mangrove forest of Mojo village. The most dominant gastropod species was Telescopium telescopium, followed by Cerithidea cingulata. The analysis of heterogeneity index showed a low value for mangrove community and medium value for the gastropod community, ranging from 0.353 to 0.720 and 1.462 to 1.812, respectively. Statistical data analysis showed that the density of R. mucronata and A. marina had a significant effect on the abundance of gastropod specieses, including Cerithidea quadrata and Casidula nucleus, both of which had logarithmic relationship trends.
EN
Let ∑ be an alphabet which has at least two symbols. The density of L ⊆ ∑* is defined as D(L) := limn |L ∩ ∑n|/|∑n| ∈ [0, 1], provided that the limit exists. In 2015, R. Sin’ya has discovered an interesting relation between regular languages and their densities: If L ⊆ ∑* is a regular language, then D(L) = 0 if and only if there exists s ∈ ∑* such that ∑*s∑* ∩ L = Ø. In this paper, we give a simple proof of this theorem, obtaining it as a simple consequence of the pumping lemma for regular languages.
EN
Crystal density is a basic and important parameter for predicting the detonation performance of explosives, and nitrate esters are a type of compound widely used in the military context. In this study, thirty-one aliphatic nitrates were investigated using the density functional theory method (B3LYP) in combination with six basis sets (3-21G, 6-31G, 6-31G*, 6-31G**, 6-311G* and 6-31+G**) and the semiempirical molecular orbital method (PM3). Based on the geometric optimizations at various theoretical levels, the molecular volumes and densities were calculated. Compared with the available experimental data, the densities calculated by various methods are all overestimated, and the errors of the PM3 and B3LYP/3-21G methods are larger than those of other methods. Considering the results and the computer resources required by the calculations, the B3LYP/6-31G* method is recommended for predicting the crystalline densities of organic nitrates using a fitting equation. The results obtained with this method are slightly better than those reported by Keshavarz and Rice. In addition, the effects of various groups (such as –ONO2, –OH, –Cl, –O–, and –CH2–) on the densities are also discussed, which is helpful for the design of new molecules in terms of practical requirements.
EN
Polyethylene glycol polynitrates may be used as plasticizers in propellants. In this study, ten derivatives of ethylene glycol dinitrate were investigated using the density functional theory method. The fitted densities (ρ’exp.) were obtained and were very close to the experimental values. The detonation properties were predicted using the modified Kamlet-Jacobs equations and the specific impulse (Is) was evaluated according to the largest exothermic principle. A new indicator, K = Is · ρ’exp., is proposed to evaluate the energetic characteristics of the plasticizers. Thermal stability is discussed by calculating the bond dissociation energies or energy barriers. The O−NO2 bond is the trigger bond for all of the compounds studied. Considering the energetic properties and stability, diethylene glycol tetranitrate, triethylene glycol hexanitrate, tetraethylene glycol octanitrate, pentaethylene glycol decanitrate and hexaethylene glycol dodecanitrate are potential energetic plasticizers for solid propellants. The influences of the −O−CH2−CH2− and −O−CH(ONO2)−CH(ONO2)− groups are also discussed, which will be helpful for the design of new highly energetic plasticizers by modifying the structures as required.
EN
The Mn-Zn ferrite powders prepared by high energy ball milling were heat-treated, subsequently compacted and sintered by spark plasma sintering (SPS). Based on the observation of microstructure, the characteristics of samples after SPS were investigated and compared with ones after conventional sintering. The size of initial powders was approximately 650 nm and decreased to 230 nm after milling at 300 rpm for 3 h. After heat treatment at 973 K for 1 h, the milled powders became larger to approximately 550 nm in size again and the peaks of Mn2 O3 disappeared in XRD patterns. In the samples after SPS, the Fe2 O3 and MnZnFe2 O4 phases decomposed at the higher temperatures than 1173 K and 1373 K, respectively, while only MnZnFe2 O4 phase was detected in the samples conventionally sintered at 1273~1673 K. As the sintering temperature increased, the relative density after SPS increased more quickly than that after conventional sintering. In particular, it reached approximately 99% after SPS at 1473 K.
EN
Even though soil mass density is among the basic characteristics of a soil mass, it has not been analysed in terms of wear impact on steel. This paper presents the results of testing for the wear of abrasion-resistant steel within a soil mass with varied density. The experiment was carried out under laboratory conditions using the “rotating bowl” method in a medium soil with varied moisture content. The following were determined: mass wear, an assessment of the friction coefficient development, and the image of the surface after the friction test. It was found that, within a soil mass with a significant plastic fraction content, the greatest wear of soil occurred for a density of approx. 1.4 g/cm3.
PL
Gęstości masy glebowej, pomimo że należy ona do podstawowych charakterystyk masy glebowej, dotychczas nie opisano w aspekcie oddziaływania zużyciowego stali. Przedstawiono wyniki badania zużycia stali odpornej na zużycie ścierne w masie glebowej o zróżnicowanej gęstości. Eksperyment przeprowadzono w warunkach laboratoryjnych metodą „wirującej misy” w glebie średniej o zróżnicowanej wilgotności. Wyznaczono zużycie masowe, ocenę kształtowania się współczynnika tarcia oraz obraz powierzchni po badaniu tarcia. Stwierdzono, że w masie glebowej o znacznej zawartości frakcji plastycznych największe zużycie stali wynosi dla gęstości przyjmującej wartość ok. 1,4 g/cm3.
15
Content available remote Towards the Cracow Metropolis – a dream or a reality? A selected issues
EN
Cracow, the former capital of Poland and currently the second-largest Polish city, dreams of becoming the most important metropolis – not only of the Lesser Poland region, but also of the entire southern and south-eastern part of Poland. This paper, based on long-term research and field studies, also refers, in part, to the “Model of the Spatial Structure of Cracow” research programme, which was conducted at the Institute of Urban Design of the CUT under the guidance of M. Gyurkovich with collaboration with A. Sotoca, between October 2016 and July 2017. This is the background against which the selected issues of spatial transformations that took place within the city limits and that influence the urban morphology of Cracow, will be presented against. The type of spatial structure that can currently be observed in Cracow, does not bring to mind an association with the urban form of a European Metropolis. Can the contemporary attempts to create a polycentric urban organism- that can compete with other, well-organised ones, internationally, ever be successful? Will the dream of the Cracow Metropolis ever come true?
PL
Kraków, była stolica Polski i obecnie drugie polskie miasto, marzy o staniu się najważniejszą metropolią nie tylko regionu Małopolski, ale także całej południowej i południowo-wschodniej Polski. Niniejszy artykuł, oparty o długotrwałe badania i studia terenowe, również odnosi się częściowo do programu badawczego „Model Struktury Przestrzennej Krakowa”, opracowanego w Instytucie Projektowania Urbanistycznego PK pod kierunkiem M. Gyurkovicha przy współpracy z A. Sotocą między październikiem 2016 a lipcem 2017 roku. Stanowi on tło, na którym będą prezentowane wybrane zagadnienia przekształceń przestrzennych, które miały miejsce w obrębie miasta, i które wywierają wpływ na morfologię urbanistyczną Krakowa. Rodzaj struktury przestrzennej, który można obecnie zaobserwować w Krakowie, nie wywołuje konotacji z formą urbanistyczną Europejskiej Metropolii. Czy współczesne próby stworzenia policentrycznego miejskiego organizmu, który mógłby konkurować z innymi, dobrze zorganizowanymi miastami na płaszczyźnie międzynarodowej mogą zakończyć się powodzeniem? Czy marzenie o Krakowskiej Metropolii kiedykolwiek się spełni?
EN
TiC particle-reinforced AISI 316L stainless-steel matrix composites were prepared using conventional powder metallurgy technology. The effect of TiC content on the microstructure and properties of these composites has been investigated with a particular emphasis upon hardness, wear resistance and corrosion resistance in sea water environments. The results showed that TiC particle reinforcement improved the hardness, wear resistance and corrosion resistance of AISI 316L stainless steel. The higher TiC content in the studied composites resulted in a higher hardness of the wear surface and a lower wear rate. The best corrosion resistance in sea water was achieved for sintered AISI 316L – 5% TiC composite.
PL
Konwencjonalną technologią metalurgii proszków wytworzono umacniane cząstkami TiC kompozyty o osnowie austenitycznej stali AISI 316L. Dokonano oceny wpływu udziału cząstek TiC na mikrostrukturę i właściwości tych kompozytów, w szczególności twardość, odporność na zużycie ścierne i odporność na korozję w środowisku wody morskiej. Stwierdzono, że umocnienie cząstkami TiC doprowadziło do poprawy twardości, odporności na zużycie ścierne i odporności na korozję stali AISI 316L. Wraz ze wzrostem udziału TiC w badanych kompozytach wzrastała twardość powierzchni zużycia, a malała jej szybkość. Natomiast najlepszą odporność na korozję w wodzie morskiej wykazał spiekany kompozyt AISI 316L – 5% TiC.
17
Content available remote Model reologiczny dla gęstych emulsji
PL
Przedstawiono metodę modelowania reologii gęstych, polidyspersyjnych emulsji oraz zastosowano tę metodę w kombinacji z CFD i równaniem bilansu populacji do modelowania przepływu emulsji i dyspersji kropel w mieszalnikach typu rotor-stator. Przedstawiono wpływ warunków formulacji emulsji na jej właściwości reologiczne. Zbadano wpływ obecności zaadsorbowanej na powierzchni kropel warstewki polimeru; efekt grubości warstewki jest znaczący tylko dla niskich szybkości ścinania. Określono również wpływ ułamka objętości fazy rozproszonej dla maksymalnego upakowania na lepkość emulsji.
EN
A method for modeling rheology of dense polydispersed emulsions is presented and applied in combination with CFD and population balance equation to model flow of viscous emulsion and drop dispersion in the high-shear rotor-stator mixer. Effect of process conditions during emulsion formulation on resulting emulsion rheology is presented. Effects on rheology of adsorbed polymer layer present on drop surface are investigated. It has been shown that these effects are significant at small shear rate. Effects of maximum packing volume on emulsion rheology are studied as well.
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EN
Nowadays, with the understanding of the importance of the green building concept, there is a constantly increasing demand for ecological construction materials. The application of raw materials from renewable sources such as wood, plants and waste to building materials preparing has gained a significant interest in this research area. With the consideration of environmental consciousness, natural fibers are biodegradable so as they can alleviate the problem of massive solid waste produced and relief the pressure of landfills, they are used for replacing other non-degradable materials for product development. In this experimental work, wood pulp and recycled waste paper fibers in addition 0.2%, 0.3% and 0.5% were used. The fiber cement composites were subjected to a characterization of their composition including the assessment of a complex set of basic physical and mechanical properties after 7 and 28 days of hardening. Experimental results show that application of small amount of cellulosic fibers lead to a reduction of density up to 6% when compared with the reference composite. However, cement composites based on wood pulp showed better mechanical properties such as compressive and flexural strength in comparison with cement composites with recycled waste paper fibers.
EN
In this study, a new and reliable model is derived for predicting the density of tetrazole N-oxide salts using molecular structure descriptors through multiple linear regression methods (MLR). The proposed model is based on the elemental, functional group and type of molecule descriptors. The coefficient of determination (R2) of the model was 0.9321 for 36 energetic tetrazole N-oxides with different molecular structures as an exploratoryset. The predictive ability of this model has been checked using a cross validation method (Q2 LOO = 0.9325 and Q2 LMO = 0.9324). The new correlation had a root mean square deviation (RMSD) of 0.033 g·cm−3 and an average absolute deviation (AAD) of 0.025 g·cm−3. This correlation also gave good predicted results for a further 10 energetic tetrazole N-oxides as a test set. The new reliable model can also be appliedfor designing novel energetic tetrazole N-oxides.
EN
A novel wool absorption board was prepared by using a traditional non-woven technique with coarse wools as the main raw material mixed with heat binding fibers. By using the transfer-function method and standing wave tube method, the sound absorption properties of wool boards in a frequency range of 250-6300 Hz were studied by changing the thickness, density, and cavity depth. Results indicated that wool boards exhibited excellent sound absorption properties, which at high frequencies were better than that at low frequencies. With increasing thickness, the sound absorption coefficients of wool boards increased at low frequencies and fluctuated at high frequencies. However, the sound absorption coefficients changed insignificantly and then improved at high frequencies with increasing density. With increasing cavity depth, the sound absorption coefficients of wool boards increased significantly at low frequencies and decreased slightly at high frequencies.
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