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Tytuł:
From palaeosols to carbonate mounds: facies and environments of the middle Frasnian platform in Belgium
Autorzy:
Silva da, A. C.
Boulvain, F.
Powiązania:
https://bibliotekanauki.pl/articles/2058840.pdf
Data publikacji:
2004
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Belgium
middle Frasnian
carbonate platform
palaeogeography
facies
carbonate mounds
Opis:
This paper provides a synthetic sedimentological overview of themiddle Frasnian carbonate platform of Belgium and associated carbonate mounds. Carbonate mounds started usually in a relatively deep, quiet subphotic environment with a crinoid-coral-sponge assemblage, then reached the fair-weather wave base and the euphotic zone with an algal-microbial facies. The upper parts of themounds are characterised by lateral facies differentiation with the algal-microbial facies protecting a central sedimentation area with a dendroid stromatoporoids facies and fenestral limestone. The lateral facies reflect different kinds of input of reworked mound material in the proximal area, from transported fine-grained sediment to coarse-grained fossil debris. On the platform, environments range from the outer zone (crinoidal facies) to stromatoporoid-dominated biostromes and to the lagoonal area of the inner zones (subtidal facies with Amphipora floatstone, algal packstone, intertidal mudstone and laminated peloidal packstone and palaeosols). These facies are stacked in metre-scale shallowing-upward cycles. The larger scale sequential organisation corresponds to transgressions and regressions, whose cycles are responsible for differentiating a lower open-marine biostrome dominated unit from an upper lagoonal unit. The last regression- transgression cycle, responsible for the platform-scale development of lagoonal facies, can be correlated with an atoll-stage evolution of the carbonate mounds belonging to the Lion Member.
Źródło:
Geological Quarterly; 2004, 48, 3; 253--266
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The earliest Cretaceous carbonate platform destroyed by volcanism from the Ukrainian/Romanian Carpathians – reconstruction based on microfacies
Autorzy:
Iwańczuk, Joanna
Krobicki, Michał
Feldman-Olszewska, Anna
Hnyłko, Oleh
Powiązania:
https://bibliotekanauki.pl/articles/24202094.pdf
Data publikacji:
2023
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Carpathians
Cretaceous
carbonate
Opis:
There is a unique tectonostratigraphic unit called Kaminnyi Potik occur in the Ukrainian-Romanian Carpathian transborder zone. In the Ukrainian part numerous outcrops of this unit can be observed in many streams near Rachiv city, but its most spectacular occurrence is in the Chyvchyn Mountains. The whole complex consists of volcanogenic-sedimentary rocks and is divided into two Berriasian formations: Chyvchyn and Kaminnyi Potik. In the section of the Chyvchyn Formation, at the base, there are pillow lavas (basalts and andesites/trachyandesites) and volcano-sedimentary breccia with clasts of lava, coral limestones and radiolarites (submarine debris flows), and peperites as well. The Kaminnyi Potik Formation is made up of fine-grained hyaloclastic and carbonate debris flows of a flysch character (including organodetrital limestones with fragments of: corals, bryozoans, echinoderms bivalves and foraminifera), which overlying breccias and coral limestones of the Chyvchyn Formation. The profile ends by thin-bedded cherty limestones. The thin sections analysis revealed the following microfacies: oolithic-echinoderm packstone/grainstone; coral lithoclastic quartz packstone/grainstone; oolithic-lithoclastic wackestone/packstone; lithoclastic-echinoderm packestone; lithoclastic packestone; radiolarian echinoderm packestone; radiolarian wackestone; radiolarian-calpionellid wackestone and mudstone. Pyroclastic material is often present in the matrix. The ooids observed in the thin sections and the remains of fauna such as corals, echinoderms and bivalves suggest that the original material came from a carbonate platform that was sheltered by a coral reef. As a result of volcanic eruptions and possibly accompanying earthquakes, the platform has been destroyed and its traces are visible in clasts. Sedimentological character of submarine debris flows, (e.g. fractional graiding, mixture of shallow-water fauna and lithoclasts with deep-marine microfauna (radiolarians and calpionellids) and hyaloclastic material present in the matrix document short-term episodes of a catastrophic nature, leading to the redeposition of shallow-water sediments to the deeper parts of the basin.
Źródło:
Geotourism / Geoturystyka; 2023, 1-2 (72-73); 31--31
1731-0830
Pojawia się w:
Geotourism / Geoturystyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Oligowęglanodiole otrzymywane z "zielonych monomerów" węglanowych jako segmenty miękkie poliuretanów
Oligocarbonate diols obtained from carbonate "green monomers" as soft segments of polyurethanes
Autorzy:
Tomczyk, K.
Pawłowski, P.
Parzuchowski, P.
Rokicki, G.
Powiązania:
https://bibliotekanauki.pl/articles/143061.pdf
Data publikacji:
2010
Wydawca:
Stowarzyszenie Inżynierów i Techników Przemysłu Chemicznego. Zakład Wydawniczy CHEMPRESS-SITPChem
Tematy:
oligowęglanodiole
poliuretany
węglan etylenu
węglan dimetylu
węglan trimetylenu
oligocarbonate diols
polyurethanes
ethylene carbonate
dimethyl carbonate
trimethylene carbonate
Opis:
Przedstawiono różne metody otrzymywania oligowęglanodioli (OWD) z surowców przyjaznych dla środowiska. Szczególnie atrakcyjne metody oparte są na dwutlenku węgla i prostych estrach kwasu węglowego, takich jak: węglan etylenu, węglan trimetylenu i węglan dimetylu. Otrzymane tymi metodami oligomerole nie zawierają wtrąceń eterowych w swojej strukturze, a ich cząsteczki zakończone są jedynie grupami hydroksylowymi. Mogą one zawierać od 3 do 13 atomów węgla w jednostce powtarzalnej, a ich masy molowe wahają się w granicach 1000 do 3000 g/mol. Wykazano, że używając węglanu dimetylu (DMC) można otrzymać ciekłe (ko)oligomery o strukturze nieregularnej, a w procesie polimeryzacji węglanu trimetylenu inicjowanej oligomerolami otrzymuje się (ko)oligomery o budowie blokowej, zawierające fragmenty oligo(dimetylosiloksanowe), szczególnie przydatne w zastosowaniach medycznych. W wyniku polimeryzacji węglanu trimetylenu inicjowanej produktem reakcji heksametylenodiaminy z węglanem etylenu można otrzymać oligowęglanodiole zawierające ugrupowania uretanowe, bez konieczności stosowania toksycznych izocyjanianów. Poliuretany zawierające oligowęglany jako segmenty miękkie są szczególnie atrakcyjne ze względu na ich odporność na czynniki utleniające. Otrzymane oligowęglanodiole mogą być użyte w procesie otrzymywania elastomerów poliuretanowych do zastosowań medycznych. Na ich podstawie otrzymano folie poliuretanowe, które charakteryzowały się bardzo dobrymi właściwościami mechanicznymi: wytrzymałość na rozciąganie, w zależności od masy molowej oligowęglanodiolu i jego budowy chemicznej wahała się w granicach od 35 MPa (oligo(węglan trimetylenu) o Mn = 1500 g/mol) do 50 MPa (oligowęglan na bazie 1,6-HD/1,4-BD (1/2) o Mn = 1400 g/mol), a wydłużenie przy zerwaniu od 420% (OWD + OSD o Mn = 1720 g/mol) do 750% (oligo(węglan trimetylenu) o Mn = 1500 g/mol).
This paper presents various methods of oligocarbonate diols (OWDs) synthesis based on environmentally friendly materials. Taking into account the price and availability of raw materials, lack of hazardous by-products and the process efficiency, especially attractive methods of oligocarbonate diols obtaining seem to be those in which carbon dioxide and simple esters of carbonic acid such as ethylene carbonate, trimethylene carbonate and dimethyl carbonate are used. We have developed the preparation methods of oligomerols, which do not contain ether units and their macromolecules are exclusively terminated with hydroxyl groups. Depending on the method of synthesis oligocarbonate diols can contain 3 to 13 carbon atoms in the repeating unit and are characterized by molecular weight in the range of 1000-3000. It has been shown that applying the method based on dimethyl carbonate (DMC) when two different diols are used liquid co-oligomers of irregular structure can be obtained. Moreover, applying the polymerization method co-oligomers with oligo(dimethylsiloxane) and oligocarbonate blocks can be easily formed when oligo(dimethylsiloxane)diol was used as an initiator for thermal polymerization of trimethylene carbonate. In the paper a new non-isocyanate reaction pathway leading to oligocarbonate diols containing urethane groups was also presented. According to this method the reaction product of alkylene diamine (e.g. hexamethylenediamine) with ethylene carbonate is used as the initiator for polymerization of trimethylene carbonate. The oligocarbonate diols can be used to manufacture biomedical polyurethanes of various purposes. Polyurethanes with oligocarbonate soft segments based on longer diols are particularly attractive as materials for implants due to their resistance to hydrolysis and oxidizing agents. Those based on short diols can be used as biodegradable materials. Polyurethane films obtained on the basis of oligocarbonate diols exhibited very good mechanical properties: tensile strength, depending on the molecular masses of oligocarbonate diol and its chemical structure, varied from 35 MPa (oligo(trimethylene carbonate), Mn = 1500 g/mol) to 50 MPa (oligocarbonate diol based on 1,6-HD/1,4-BD (1/2), Mn = 1400 g/mol), and elongation at a break from 420% (OWD + OSD, Mn = 1720 g/mol) to 750% (oligo(trimethylene carbonate), Mn = 1500 g/mol).
Źródło:
Chemik; 2010, 64, 4; 284-293
0009-2886
Pojawia się w:
Chemik
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation of different zinc compounds from a smithsonite ore through ammonia leaching and subsequent heat treatment
Autorzy:
Ehsani, Arman
Ehsani, Ilhan
Obut, Abdullah
Powiązania:
https://bibliotekanauki.pl/articles/1445772.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
ammonia leaching
smithsonite
zinc ammine carbonate
zinc carbonate hydroxide
zinc oxide
Opis:
In this study, firstly, the effects of ammonia concentration, leaching time and solid/liquid ratio on the leaching behaviour of zinc from a smithsonite (ZnCO3) ore sample in aqueous ammonia solutions were investigated at room temperature by chemical, X-ray diffraction (XRD) and Fourier-transform infrared (FT-IR) spectroscopy analyses. It was found that leaching ratio of zinc steeply increased from 30.1 to 76.2% with increasing ammonia concentration from 1.0 to 4.0 M and maximum zinc leaching ratio of 79.7% was reached after leaching in 13.3 M NH3 solution. The XRD pattern of the residue obtained after leaching in 4.0 M NH3 solution for 90 min at solid/liquid ratio of 0.15 g/mL, the optimum condition, showed that smithsonite phase in the ore sample almost completely dissolved whereas the gangue minerals goethite and calcite remained unaffected, confirming the selectivity of ammonia solution for zinc dissolution. Together with zinc, leaching ratios of cadmium were also determined. In second part of the study, precipitation tests (by complete drying at different temperatures) were conducted on dissolved zinc, carbonate and ammonia containing pregnant solutions obtained after selected leaching experiments. By complete drying of the pregnant solutions at low temperatures, i.e. 50°C, relatively pure solid zinc ammine carbonate (Zn(NH3)CO3) precipitates and at higher temperatures, i.e. 150°C, quite pure solid zinc carbonate hydroxide (Zn5(CO3)2(OH)6) precipitates could be prepared. High-temperature heating of Zn(NH3)CO3 and Zn5(CO3)2(OH)6 precipitates at 450°C yielded single-phase zinc oxide (ZnO). The chemical compositions, FT-IR spectra and scanning electron microscope (SEM) photographs of some of the precipitates were also presented.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 4; 96-106
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bioceramic micro and nanoparticles as functional biological materials
Autorzy:
Parakhonskiy, B.
Saveleva, M.
Svenskaya, Y.
Ivanova, A.
Lengert, E.
Alebastrova, A.
Yashchenok, A.
Gorin, D.
Bukreeva, T.
Marchenko, I.
Douglas, T.
Skirtach, A.
Powiązania:
https://bibliotekanauki.pl/articles/284720.pdf
Data publikacji:
2017
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
calcium carbonate
biomaterials
properties
Źródło:
Engineering of Biomaterials; 2017, 20, no. 143 spec. iss.; 77
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Extracellular polymeric substance of Rhodococcus opacus bacteria effects on calcium carbonate formation
Autorzy:
Szcześ, A.
Czemierska, M.
Jarosz-Wilkołazka, A.
Magierek, E.
Chibowski, E.
Hołysz, L.
Powiązania:
https://bibliotekanauki.pl/articles/109802.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
calcium carbonate
exopolymer
mineralization
Opis:
An extracellular substance extracted from the bacterial strain Rhodococcus opacus was used as a template for calcium carbonate precipitation from CaCl2 and Na2CO3 solutions at 25 and 37 °C. Obtained crystals were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Raman spectroscopy. Kinetics of precipitation was investigated by conductivity measurements. The obtained results show that the used biopolymer does not affect the crystal structure but acts as a nucleation centers leading to the formation of calcite crystals with the regular size. This effect is concentration dependent i.e. the EPS concentration increase causes the crystal size decreases, and is greater if calcium chloride solution if mixed with EPS 15 min before the addition of sodium carbonate solution. The temperature increase strengthens this effect.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 1; 142-150
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The margins of the Early Jurassic Trento Platform (Southern Alps)
Autorzy:
Riva, Alberto
Gianolla, Piero
Caggiati, Marcello
Powiązania:
https://bibliotekanauki.pl/articles/24202119.pdf
Data publikacji:
2023
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Alps
Early Jurassic
carbonate
Opis:
Examples of Lower Jurassic carbonate platform margins are rare, probably due to the scarcity of good outcrops. One of the major palaeogeographic units of the Mesozoic Tethys, the Trento Platform, however, shows two different margin types facing the Belluno and the Lombardian basins. While the western margin, facing the Lombardian Basin, is showing an ooidal unit with frequent mud mounds (Massone Oolite), the eastern margin was poorly characterized, mainly due to difficult stratigraphic definition and problematic accessibility of outcrops. The eastern platform margin characteristics are strictly controlled by tectonic activity and the type of carbonate factory; the differences between the eastern and the western margin could be linked to windward-leeward position of the platform margin, more protected to the west than to the east. Subsidence increased since Late Triassic, due to the opening of the Alpine Tethys, defining shallow water areas, dominated by subtidal and peritidal muddy carbonates, and deeper basins, such as the Belluno and Lombardian Basin. More than 500 m of mud-dominated carbonates developed until Early Sinemurian, when major switch in the carbonate factory occurred. The Hettangian-Early Sinemurian margin is usually not well exposed and is strongly dolomitized and appears to be a tectonically controlled escarpments. Since Late Early Sinemurian, the carbonate factory changed and led to a huge production of peloids and ooids, promptly shed in the surrounding basin: in the Eastern Trento Platform we recognize a 400/500 m thick wedge of Sinemurian to Pliensbachian ooidal calcarenites pinching-out towards the basin, with scattered bioconstructions made of calcareous sponges across the margin. This wedge pinches out also towards the platform interior, showing that the ooids were poorly preserved on the platform top. The preserved slope shows an angle of about 20-25°. In the western margin, the resedimented ooids are more limited, probably due to the limited size of the marginal carbonate factory. In the Late Pliensbachian, probably in the Margaritatus zone, a drowning phase affected part of the eastern carbonate platform, switching to encrinitic calcarenites, while in the western one carbonate production continued until Bajocian. These encrinites are extremely thin on the platform top, but a resedimented wedge in the proximal basin highlights the position of the topographic margin. The margins of the Trento Platform is a rare example of Early Jurassic carbonate platform margin that can be used as a reference for coeval carbonate platform depositional systems.
Źródło:
Geotourism / Geoturystyka; 2023, 1-2 (72-73); 59--59
1731-0830
Pojawia się w:
Geotourism / Geoturystyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Methods of investigation of alkali-carbonate reaction in concrete based on the tests of aggregate reactivity
Metody badań reakcji alkalia-węglany w betonie na tle badań reaktywności kruszywa
Autorzy:
Owsiak, Z.
Czapik, P.
Powiązania:
https://bibliotekanauki.pl/articles/402436.pdf
Data publikacji:
2011
Wydawca:
Politechnika Świętokrzyska w Kielcach. Wydawnictwo PŚw
Tematy:
kruszywo węglanowe
reakcje alkalia-węglany
metody testowania
carbonate aggregate
alkali-carbonate reaction
testing methods
Opis:
There are numerous methods of testing aggregate reactivity, most of which can be classified into a few basic groups, with regard to the object of research. With the knowledge on what particular methods are capable of it is possible to plan the appropriate course of action. It is especially important when the reaction mechanisms are not exactly known, as in the case of the reaction of alkalis with carbonate aggregate (ACR). The properties of these aggregates make the application of testing methods different than those for silica aggregates not only advisable, but sometimes also necessary. The tests on the reactivity of silica aggregates provide the basis for the formulation of the majority of standards fOr AAR testing that are in force today. The objective of this paper is to present the methodology of ACR testing, taking into consideration the properties of this aggregate.
Źródło:
Structure and Environment; 2011, 3, 2; 18-24
2081-1500
Pojawia się w:
Structure and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Depositional environments, facies and diagenesis of the Upper Jurassic–Lower Cretaceous carbonate deposits of the Buila-Vânturariþa Massif, Southern Carpathians (Romania)
Autorzy:
Pleş, G.
Bucur, I. I.
Săsăran, E.
Powiązania:
https://bibliotekanauki.pl/articles/191844.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
Carbonate platforms
reefs
microfacies
micro-encrusters
carbonate diagenesis
Upper Jurassic
lowermost Cretaceous
Southern Carpathians
Romania
Opis:
The Buila-Vânturariţa Massif consists of massive Upper Jurassic reef limestones (Kimmeridgian–Tithonian) and Lower Cretaceous (Berriasian–Valanginian, and Barremian–?Lower Aptian) deposits. Besides corals and stromatoporoids, a wide range of micro-encrusters and microbialites has contributed to their development. In this study, the authors describe briefly and interpret the main facies associations and present the microfossil assemblages that are important for age determination. The distribution of facies associations, corroborated with the micropalaeontological content and early diagenetic features, indicate different depositional environments. The carbonate successions show the evolution of the Late Jurassic–Early Cretaceous depositional environments from slope and reef-front to internal-platform sedimentary settings, including peritidal environments in the lowermost Cretaceous. Early diagenesis, represented by synsedimentary cementation in the form of micritization (including cement crusts in the reef microframework), followed by dissolution, cementation and dolomitization in a meteoric regime, and void-filling late cementation during the burial stage.
Źródło:
Annales Societatis Geologorum Poloniae; 2016, 86, 2; 165-183
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and properties of bioresorbable and highly flexible 1,3-trimethylene carbonate/ε-caprolactone copolymers
Autorzy:
Pastusiak, M.
Dobrzyński, P.
Smola, A.
Sobota, M.
Powiązania:
https://bibliotekanauki.pl/articles/285683.pdf
Data publikacji:
2012
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
copolymerization
caprolactone
trimethylene carbonate
bioresorbable polymers
Opis:
Ethyl etoxy zinc (II) has been prepared and emerged as very effective initiators for ring-opening polymerization of 1,3-trimethylene carbonate (TMC) and its copolymerization with ε-caprolactone (CL) to produce high molar mass polymers. The copolymerization of TMC and CL was performed in bulk at 120°C. The obtained copolymers were characterized by multiblock microstructure. The highest reactivity rate was demonstrated by trimethylene carbonate in comparison with ε-caprolactone monomer. The thermal and mechanical properties of the copolymers were strongly dependent on the monomer composition. Preliminary tests of monomers copolymerization using reactive extrusion yielded positive result.
Źródło:
Engineering of Biomaterials; 2012, 15, 113; 9-12
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reducing Creep Rate of polypropylenes by Soaking Solid solutions of CaCO3
Autorzy:
Hussain, Randa K.
Dagher, Hala F.
Khudadad, Rasol Rahman
Powiązania:
https://bibliotekanauki.pl/articles/1182918.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
creep
polypropylene
calcium carbonate
creep rate
Opis:
The creep behavior of Polypropylene and Polypropylene/Calcium Carbonate were investigated by tested them at different concentration of Calcium carbonate filler (filler addition is done by soaked pp samples in CaCO3 solution) at different temperatures. A dramatically changed in the FTIR was observed when pp soaked in CaCO3 solution comparing with pristine one. It was found that the creep rate was lowered comparing to the pure Polypropylene. The Creep behavior of the polymer formed was observed to increase with increase in temperature and stress, Calcium carbonate enhanced creep rate and rapture time.
Źródło:
World Scientific News; 2016, 49, 2; 90-103
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calcium carbonate mineralization. Part 1, The effect of poly(ethylene glycol) concentration on the formation of precipitate
Autorzy:
Polowczyk, I.
Bastrzyk, A.
Kozlecki, T.
Sadowski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/110925.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
calcium carbonate
calcite
vaterite
mineralization
PEG
Opis:
In this study, the role of polymer in precipitation has been examined by studying the effect of poly(ethylene glycol) (PEG) on the formation of calcium carbonate particles. The CaCO3 particles were characterized by several techniques, such as FTIR, XRD, SEM, and particle size distribution analysis. In the absence of polymer, the mixing of reagents in an aqueous solution led to the formation of calcite crystals. Introduction of poly(ethylene glycol) molecules reduced the rate of crystallization process, and the effect was concentration dependent. In the presence of 0.05, 0.1, and 0.5 % of PEG, after 5 minutes of precipitation initiation, vaterite microspheres appeared in the system and which were transformed into calcite crystals after 24 hours. The calcium carbonate obtained with PEG was characterized by smaller sized particles in comparison with the ones without polymer.
Źródło:
Physicochemical Problems of Mineral Processing; 2013, 49, 2; 631-639
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigations on the synthesis and properties of biodegradable poly(ester-carbonate-urea-urethane)s
Autorzy:
Mazurek, M. M.
Rokicki, G.
Powiązania:
https://bibliotekanauki.pl/articles/779133.pdf
Data publikacji:
2013
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
polyurethane
oligo(ester-carbonate) diol
biodegradation
Opis:
A new method of the synthesis of oligo(tetramethylene succinate-co-carbonate) diols using dimethyl succinate, 1,4-butanediol and tetramethylene bis(methyl carbonate) was elaborated. The resultant oligomerols (Mn = 2600- 3700) were characterized by FTIR, 1H NMR, GPC and DSC analysis. Depending on the content of carbonate units in the polymer molecules, the melting point of the crystalline phase changes significantly. The synthesis of poly(ester-carbonate-urea-urethane)s was carried out with two aliphatic diisocyanates - cyclic IPDI or linear HDI. The resultant products exhibited very good mechanical properties - tensile strength up to 60 MPa and elongation at break about 500%. Preliminary studies confirmed that the presence of ester units in the soft segments as well as lack of crystalline phase significantly enhances the biodegradability of the PUR in comparison to that of polyurethanes based on carbonate oligomers.
Źródło:
Polish Journal of Chemical Technology; 2013, 15, 4; 80-88
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Neuro-fuzzy modelling of blending process in cement plant
Autorzy:
Araromi, D O
Odewale, S A
Hamed, J O
Powiązania:
https://bibliotekanauki.pl/articles/102547.pdf
Data publikacji:
2015
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
neuro-fuzzy
blending
carbonate content
raw mix
Opis:
The profitability of a cement plant depends largely on the efficient operation of the blending stage, therefore, there is a need to control the process at the blending stage in order to maintain the chemical composition of the raw mix near or at the desired value with minimum variance despite variation in the raw material composition. In this work, neuro-fuzzy model is developed for a dynamic behaviour of the system to predict the total carbonate content in the raw mix at different clay feed rates. The data used for parameter estimation and model validation was obtained from one of the cement plants in Nigeria. The data was pre-processed to remove outliers and filtered using smoothening technique in order to reveal its dynamic nature. Autoregressive exogenous (ARX) model was developed for comparison purpose. ARX model gave high root mean square error (RMSE) of 5.408 and 4.0199 for training and validation respectively. Poor fit resulting from ARX model is an indication of nonlinear nature of the process. However, both visual and statistical analyses on neuro-fuzzy (ANFIS) model gave a far better result. RMSE of training and validation are 0.28167 and 0.7436 respectively, and the sum of square error (SSE) and R-square are 39.6692 and 0.9969 respectively. All these are an indication of good performance of ANFIS model. This model can be used for control design of the process.
Źródło:
Advances in Science and Technology. Research Journal; 2015, 9, 28; 27-33
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Konzentrat-Lagerstätte-type carbonate concretions from the uppermost Bajocian (Middle Jurassic) of the Częstochowa area, South-Cental Poland
Autorzy:
Zatoń, M.
Marynowski, L.
Powiązania:
https://bibliotekanauki.pl/articles/2058808.pdf
Data publikacji:
2004
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Jurassic
Bajocjan
carbonate concretions
taphonomy
Lagerstätte
biomarkers
Opis:
Early-diagenetic calcitic concretions of latest Bajocian (parkinsoni Zone, bomfordi Subzone) age in the Polish Jura contain an extremely rich and well-preserved macrofauna. In addition to bivalves and brachiopods, there are numerous ammonites of the (sub)genera Parkinsonia, Nannolytoceras, Lissoceras (Lissoceras), L. (Microlissoceras), as well as rare representatives of Vermisphinctes, Strigoceras (Strigoceras) and Phylloceras. Carapaces of primitive prosopid crabs are found associated. Such a diverse and well-preserved fauna (previously unknown from Bajocian epicratonic deposits of the Polish Jura), is typical of Konzentrat-Lagerstätte-type deposits. The random distribution of the concretions in exposure and the small size of the fauna may suggest that all remains were concentrated by bottom-current action in small depressions on an uneven sea-floor. The presence of numerous small-sized ammonites may be regarded as reflecting post-spawning assemblages which sufferedmass-mortality. Although cause of their death remains unclear, storm events are a possibility. Such depressions acted as natural “traps” as well as constituted a size-limiting factor for the accumulating fauna. The fact that all elements are well preserved indicates brief post-mortem transport and rapid burial, followed by early diagenesis that protected them from compaction. The absence of such fossil-rich concretions higher in the Middle Jurassic sequence clearly shows that our current assessment of biotic diversity may be an underestimate. The carbonate concretions contain a predominantly terrestrial type of organic matter (OM). Samples analysed are extremely immature, but early diagenetic transformations of OM occurred prior to concretion formation.
Źródło:
Geological Quarterly; 2004, 48, 4; 339--350
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 231

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