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A Model of agglomerate formation during bed wetting in the process of disc granulation

100%
Obraniak A., Gluba T.
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vol. 33
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issue 1
153-165
EN
This paper presents a method for quantitative assessment of the mechanisms of nucleation and granules growth by layering in the process of bed wetting during periodic disc granulation. This study included two initial, consecutive stages of a process with defined time courses. The first phase was a time period, in which only formation of new nuclei took place, while in the second stage simultaneous nucleation and growth of granules as a result of sticking raw material grains to pre-existing nuclei occurred. Different kinds of binding liquid were used for bed wetting in each phase. In the first phase, an aqueous solution of dye was used, and pure distilled water in the second stage. The contribution of particular mechanisms to the formation of agglomerates at different time points within the second phase of the process was determined in this study. To do that the results of bed granulometric analysis, mass balance of size fractions and the analysis of contents of a marker (dye) delivered to the bed with the binding liquid during the first phase in agglomerates were used. To assess the concentration of the dye in different size fractions of the batch, spectrophotometric analysis was utilised. The study was performed using UV-VIS JASCO V-630 spectrophotometer equipped with an integrating sphere. The sieve analysis, spectrophotometric studies and mass balance were used to determine changes in the weight of the dye containing nuclei and of the nuclei containing no dye. The aforementioned analyses were also used to assess changes in the weight of formed granules and of raw material particles attached to nuclei during simultaneous nucleation and growth of granules.
2
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Study of diamond film nucleation by ultrasonic seeding in different solutions

88%
Varga M., Ižák T., Kromka A., Veselý M., Hruška K., Michalka M.
Open Physics
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2012
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vol. 10
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issue 1
218-224
EN
In this study we have investigated diamond nucleation on Si substrates by ultrasonic seeding with different liquid solutions of Ultradispersed Detonation Diamond (UDD) powder in a mixture of metal nano- or microparticles (Ni, Co, Y). The influence of different solutions on nucleation efficiency was investigated. For highlighting nucleation centers and better evaluation of the nucleation process the nucleated samples were moved into a Microwave Plasma Enhanced Chemical Vapor Deposition (MW CVD) reactor and a ”short-time” (10 min), then followed by a ”long-time” (+1 hour), diamond deposition was performed. The morphology of samples was characterized by Scanning Electron Microscopy (SEM) and the chemical composition of grown diamond layer was investigated by Raman Spectroscopy. From the measurements we found out that microsized metal particles positively influenced nucleation and the uniformity of the deposited diamond thin film. The lowest surface roughness was achieved in the case of nanodiamond powder mixed with Co and Y metal powder. The influence of Ni, Co and Y to the nucleation and early growth stage are discussed.
3
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A Model of agglomerate formation during bed wetting in the process of disc granulation

88%
Obraniak A., Gluba T.
Chemical and Process Engineering
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2012
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issue 1
4
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Influence of heterogeneous nucleation on thermodynamic properties of isotactic polypropylene

63%
Barczewski M., Dobrzyńska-Mizera M., Trzeciak M.
Polish Journal of Chemical Technology
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2013
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vol. 15
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issue 4
71-74
EN
In this paper we have investigated the effect of 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonitol sorbitol used in varying amounts (0.01 - 1 wt %) on isotactic polypropylene (iPP) matrix. We have used dynamic mechanical thermal analysis (DMTA) and differential scanning calorimetry (DSC) to study glass transition temperatures and crystallinity as a function of the nucleating agent concentration. Isotactic polypropylene samples showed a strong dependency on amount of α nucleating agent used. An increasing content of sorbitol based nucleating agent led to an increase of crystallization temperature upon cooling from the melt at constant rate and a decrease of the glass transition temperatures.
5
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Amyloidy i prionoidy – czy jest już czas, żeby się obawiać?

63%
Liberski P. P.
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2013
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vol. 13
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issue 3
230-239
EN
The new era has come to microbiology as we have realized that the unconventional viruses of kuru, Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker syndrome (GSS), scrapie, and bovine spongiform encephalopathy (BSE) are infectious amyloid proteins and that these transmissible spongiform dementias are brain amyloidoses. This quotation from a Nobel laureate, D. Carleton Gajdusek, illustrates the best the content of this paper. Amyloid is a generic term, which embraces the fibrillary cross-β-sheet quaternary structure of any protein. All amyloids, irrespective of their amino acid sequences, are formed through nucleation/polymerization reactions in which oligomeric structures (small aggregates) composed of a limited number of a given protein moiety (a seed) nucleates other moieties. As a result, the β-pleated secondary structure predominates. Such proteins are called “prionoids” as opposed to “real” prions, which are infectious, or transmissible, in a microbiological sense; they spread between individuals and cause macro-epidemics, such as kuru, BSE and iatrogenic CJD. In this review, prions and prionoids, and their inter-relatedness, will be discussed.
PL
Nadeszła nowa era mikrobiologii, kiedy zrozumieliśmy, że niekonwencjonalne wirusy kuru, choroby Creutzfeldta--Jakoba (CJD) i zespołu [obecnie „choroby”] Gerstmanna-Sträusslera-Scheinkera (GSS), scrapie, encefalopatii gąbczastej bydła (BSE) są infekcyjnymi białkami amyloidowymi i że pasażowalne encefalopatie gąbczaste są amyloidozami mózgu. Ten cytat z wypowiedzi laureata Nagrody Nobla D. Carletona Gajduska znakomicie ilustruje całość zagadnienia. Amyloid to nazwa ogólna określająca włókienkową czwartorzędową strukturę białka. Wszystkie amyloidy, niezależnie od sekwencji aminokwasów tworzących je białek, tworzą się w wyniku reakcji nukleacji/polimeryzacji, w której agregaty (oligomery), składające się z niewielkiej liczby cząsteczek białka (jądro, seed), nukleują cząsteczki białka prekursorowego, co prowadzi do zmiany konformacji przestrzennej w kierunku harmonijki-β. Choroby wywołane przez takie białka nazywa się prionoidami. „Prawdziwe” priony różnią się zasadniczo od wszystkich innych prionoidów − priony są zakaźnie w sensie mikrobiologicznym, szerzą się między osobnikami, wywołując makroepidemie, takie jak kuru, vCJD, BSE i jatrogenne przypadki CJD. W niniejszym artykule zostaną omówione podstawowe prionoidy − choroby Alzheimera i Parkinsona – oraz relacja łącząca je z chorobami prionowymi.
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