oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Examining of slurries and production of moulds by spraying method in lost wax technology
M. Nadolski,Z. Konopka,M. ??giewka,A. Zyska
Archives of Foundry Engineering , 2008,
Abstract: The work presents the results of investigation centred around the selection of a ceramic slurry composition if ceramic fibre is applied as a component of moulding material used for the lost wax technology. Producing a ceramic material of assumed parameters demands for changing the surface properties of the mineral grains. The critical concentration of solid particles or the gel point depends on the size of mineral particles, their shape and ability to aggregate. This ability has been achieved by modifying their surface properties by adding some polymer and the wetting agent (surfactant), which are adsorbed. Using the fibre material has required developing a method of its applying to the pattern set. The technology of multi-layer spraying has been recognised as the most advantageous one. The performed laboratory experiments have allowed for determining both the material composition and the parameters of its applying, such as air pressure, nozzle diameter, and the spraying distance for gravity pneumatic spraying gun.
The dimensional and shape accuracy of vacuum castings prepared in plaster moulds  [PDF]
M. Pawlak
Archives of Foundry Engineering , 2011,
Abstract: The results of laboratory test on the dimensional and shape accuracy of bronze plaster castings CuSn10, CuSn5Zn5Pb5and AlSi11 silumin are presented in this paper. The test castings were made in form of rods of length 100mm and diameters 4 mm, 7 mm and 10mm. The temperatures of molten alloys were 1120, 1160 and 1200oC for bronzes and 700, 750 and 800oC for silumins. Mould temperatures 500 and 600oC and 250 and 300oC respectively. The relative dimension change in given technological conditions by relating to the wax model. Analogical researches were made for plate-like CuSn10 bronze castings by calculating the relative dimension change in two perpendicular axis.Obtained results allowed to state that temperature of cast alloy influences the relative dimensional change, next the mould temperature and type of material (CuSn5Zn5Pb5, CuSn10, AlSi11 relatively). The transverse dimension of the mould does not influence the dimensions of test castings. Temperature of the mould as well as casting temperature do not influence the shape accuracy of the castings.
The application of optical measurements for the determination of accuracy of gear wheels casts manufactured in the RT/RP process  [PDF]
G. Budzik,M. Oleksy,M. Grzelka,M. Wieczorowski
Archives of Foundry Engineering , 2010,
Abstract: The article discusses the possibilities of using optical measurements for defining the geometric accuracy of gear wheels casts manufactured in the rapid prototyping process. The tested gear wheel prototype was cast using an aluminum alloy. The casting mould was made by means of the three-dimensional print method (3DP) with the use of a Z510 Spectrum device. The aim of the tests was to determine the geometric accuracy of the cast made by the ZCast technology in the rapid prototyping process. The tests were conducted with the use of the coordinate optical measuring method and a GOM measuring device. The prototype measurements were made in the scanning mode. The results of the measurements, saved in the STL format with the use of the scanning device software, were compared with the gear wheel 3D-CAD nominal model. The measurements enabled the determination of the real accuracy of prototypes manufactured in casting moulds by means of the ZCast technology. The selection of the measuring method was also analyzed in terms of measurement accuracy and the RP technology precision.
Permeability of mould made by lost wax casting process  [PDF]
D. Sarek,A. Trytek,J. Nawrocki
Archives of Foundry Engineering , 2009,
Abstract: Paper present results of permeability of moulds which have been made by lost casting wax process. Measurement and tests have beenmade using typical sand cast permeability tester. Measurement technique required preparing of special shape samples. All scope of tests have been realized in WSK ”PZL-Rzeszów” S.A. Results showing permeability of ceramic moulds in function of quantity layers.
Gas flow through a multilayer ceramic mould in lost wax foundry process  [PDF]
H. Matysiak,R. Haratym,M. Klabczyk
Archives of Foundry Engineering , 2009,
Abstract: The paper deals with the issues of permeability testing of ceramic moulds used in lost wax foundry process. The main issue in thetesting is to provide proper specimens of ceramic moulds (CM). The moulds have to be repeatable and must be free of internal defects ofmicrocrack type that are formed mainly during the removal of patterns from CM in the course of heat treatment.Moreover, the process of forming ceramic moulds must be similar to the general industrial process of CM moulds making regardingtheir anisotropic structure. The permeability parameter reflecting gas flow through multilayer ceramic moulds was also examined withattention to the investment casting shape accuracy.
Moulds on paintings  [PDF]
Vukojevi? Jelena B.,Ljaljevi?-Grbi? Milica V.
Zbornik Matice Srpske za Prirodne Nauke , 2005, DOI: 10.2298/zmspn0519175v
Abstract: Spores of many fungal species are present in the air. It is known that main reasons of fungal expansion in museums are inadequate relative humidity, and temperature. Regulation of these two factors can control the germination and development of moulds spores. Isolation and determination of micromycetes from objects which are exhibited and deposited in Museum of Naive Art "Ilijanum" and in the gallery "Sava umanovi " in id were done. It was analyzed 40 samples from canvas, dyes and wooden frames with visual changes. Many species of genera Alternaria, Aspergillus, Aureobasidium, Cladosporium Drechslera, Epicoccum, Penicillium; Rhizopus, Trichoderma, Ulocladium, and Wardomyces were isolated and determined.
Possibilities of improving the durability of pressure moulds  [PDF]
A.W. Orlowicz,M. Mróz,M. Tupaj,J. Betlej
Archives of Foundry Engineering , 2009,
Abstract: This study analyses factors that influence the durability of pressure moulds. Materials for pressure moulds are also characterized here, aswell as methods of refining moulds by applying coats which create a thermal and anti-erosion barrier.
Grains colonised by moulds: fungal identification and headspace analysis of produced volatile metabolites  [cached]
Laura Rizzi,Roberta Galuppi,Marco Simioli,Giorgia Canestrari
Italian Journal of Animal Science , 2010, DOI: 10.4081/ijas.2009.s2.334
Abstract: The aim of this work was to verify if the headspace analysis of fungal volatile compounds produced by some species of Fusarium can be used as a marker of mould presence on maize. Eight samples of maize (four yellow maize from North Italy and four white maize from Hungary), naturally contaminated by Fusarium and positive for the presence of fumonisins, were analyzed to detect moisture content, Aw, volatile metabolites and an enumeration of viable moulds was performed by means of a colony count technique. Headspace samples were analysed using a gas-chromatograph equipped with a capillary column TR-WAX to detect volatile metabolites of moulds. Furthermore macro and microscopic examination of the colonies was performed in order to distinguish, according to their morphology, the genera of the prevalent present moulds. Prevalent mould of eight samples was Fusarium, but other fungi, like Aspergillus, Penicillum and Mucoraceae, were observed. The metabolites produced by F.graminearum and F. moniliforme were Isobutyl-acetate, 3-Methyl-1-butanol and, only at 8 days, 3-Octanone. The incubation time can affect off flavour production in consequence of the presence of other moulds. Further studies on maize samples under different conditions are needed in order to establish the presence of moulds using the count technique and through the identification of volatile compounds.
Presence of moulds and mycotoxins in spices  [PDF]
Karan Dragica D.,Vukojevi? Jelena B.,Mili?evi? Dragan R.,Ljajevi? Milica-Grbi? V.
Zbornik Matice Srpske za Prirodne Nauke , 2005, DOI: 10.2298/zmspn0508077k
Abstract: In this paper there are presented the results of mycologic and mycotoxicologic analysis of seven spices which are being used for production of meat products. Using standard mycologic methods, in all the tested samples, we noticed a presence of moulds. By quality and quantity, most represented are genera: Aspergillus and Penicillium. With smaller occurrence there are presented genera: Rhizopus, Mucor, Paecylomyces and Absydia. Mycotoxins - ochratoxin, aflatoxins and zearalenon, are detected in samples of ground white pepper, ginger, cloves and ground caraway.
The anticyclic operad of moulds  [PDF]
Frédéric Chapoton
Mathematics , 2006, DOI: 10.1093/imrn/rnm078
Abstract: A new anticyclic operad Mould is introduced, on spaces of functions in several variables. It is proved that the Dendriform operad is an anticyclic suboperad of this operad. Many operations on the free Mould algebra on one generator are introduced and studied. Under some restrictions, a forgetful map from moulds to formal vector fields is then defined. A connection to the theory of tilting modules for quivers of type A is also described.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.