Search results for "chain"
showing 10 items of 4255 documents
Competition between chain scission and branching formation in the processing of high-density polyethylene: effect of processing parameters and of sta…
2009
Two samples of high-density polyethylene with different molecular weight were processed in a batch mixer and the rheological and structural properties were investigated. In particular, the effect of different processing parameters and the eventual presence of different stabilizers were evaluated. Actually, two reactions may occur during processing: branching/crosslinking or chain scission. The results indicate that when the processing conditions promote a scarce mobility of the macromolecular chains (lower temperatures, lower mixing speed, and higher molecular weight), branching is more favored than chain scission. On increasing the mobility of the chain (higher temperature, higher mixing s…
On the Preparation and the Characterization of Polyethylene/Polyamide Blends by Melt Processing in the Presence of an Ethylene(co)acrylic Acid Copoly…
2006
Samples of HDPE and PA6 have been meltprocessed in the presence of two new phosphazene compounds, CP-2EPOX and CP-2OXA together with an ethylene/ acrylic acid copolymer. The blends have been prepared in an industrial twin-screw extruder by using PA6 and PE in weight ratios of 25/75 and 75/25. When used, 5 phr of EAA and 0.2 phr of CP have been added. The materials have been completely characterized from a rheological, morphological, and mechanical point of view. The results indicate that the additives used caused an increase in the rupture tensile properties, of the impact strength and viscosity especially in the PE-rich blend in the presence of CP-2EPOX. This result can be attributed both …
Enhanced chain dynamics in loop-sorting-systems by means of layout optimization and a kinematic model of the polygon action
2012
Published version of an article in the journal: Structural and Multidisciplinary Optimization. Also available from the publisher at: http://dx.doi.org/10.1007/s00158-011-0743-7 Poor dynamics owing to polygon action is a known concern in mechanical applications of closed articulated chains. In this paper a kinematic model of the polygon action in large chains of loop-sorting-systems is proposed. Through optimization techniques the chain dynamics is improved by minimizing the polygon action using a parametric model of the track layout as design variables. Three formulations of the kinematic polygon action are tested on an average sized planer tracks layout to find a superior model. Verificati…
Determinación de Streptococcus Mutans y Streptococcus Sobrinus, mediante pcr cuantitativa a tiempo real, y su relación con la caries dental en escola…
2013
La caries dental presenta una etiología multifactorial, los factores ambientales, los hábitos de alimentación, higiene bucal y la susceptibilidad genética individual, juegan un papel importante en el desarrollo de esta enfermedad (1). Los Streptococcus mutans y Streptococcus sobrinus están fuertemente implicados en la aparición de la caries dental en humanos. Numerosos estudios han demostrado que la asociación de S. mutans y S. sobrinus conlleva niveles más altos de caries (2-4) y varios estudios han encontrado que la prevalencia deS. sobrinus está fuertemente asociada con mayor actividad de caries que la delS. mutans (5-6). Se considera que la determinación de estas dos especies en la infa…
Soybean Diseases Caused by Genus Pseudomonas Phytopathenes Bacteria
2019
The rationale and experimental confirmation of the role of the bacteria of the Pseudomonas genus in the pathogenesis of soybean, and the investigation of the biological properties of the main causative agent Pseudomonas savastanoi pv. glycines. Methods. Theoretical generalization, laboratory-model research, phytopathological, microbiological, physiological, biochemical and genetic methods. Results. The largest group of pathogens in different soil-climatic zones of Ukraine consists of bacteria of the genus Pseudomonas was established. Their biological properties have been investigated and the methods for identification of the dominant type of phytopathogenic bacteria causing bacterial blight…
Block copolymers from ionic liquids for the preparation of thin carbonaceous shells
2017
This paper describes the controlled radical polymerization of an ionic-liquid monomer by RAFT polymerization. This allows the control over the molecular weight of ionic liquid blocks in the range of 8000 and 22000 and of the block-copolymer synthesis. In this work we focus on block copolymers with an anchor block. They can be used to control the formation of TiO2 nanoparticles, which are functionalized thereafter with a block of ionic-liquid polymer. Pyrolysis of these polymer functionalized inorganic nanoparticles leads to TiO2 nanoparticles coated with a thin carbonaceous shell. Such materials may, e.g., be interesting as battery materials.
The pentafluorophenyl group as π-acceptor for anions: a case study
2015
Chemical science 6(1), 354-359 (2015). doi:10.1039/C4SC02762K
Podstawowe zagadnienia problematyki rekurencji treści cyfrowych
2018
Celem pracy jest wykazanie aktualnych problemów prawnych w związku z ewolucją dystrybucji treści cyfrowych oraz próbą wskazania możliwych innych kierunków zmian w podejściu do sposobu zakupu treści cyfrowej wraz z upowszechnieniem się novum w postaci rozproszonego konsensusu. Ten ostatni spowodował rozpowszechnienie się technologii łańcucha bloków, która wedle koncepcji wizjonerów ma w przyszłości pozwolić na rozproszone usługi hostingowe połączone z nowym podejściem do dystrybucji treści cyfrowych bez nośnika – zarówno dla konsumentów, jak i autorów zdigitalizowanych dzieł.
Economic Sustainability of Italian Greenhouse Cherry Tomato
2014
Greenhouse tomato cultivation plays an important role in Sicily, being the primary production area in Italy, due to its favorable pedo-climatic conditions that permit extra-seasonal productions. In Sicily, more than half of greenhouse tomato production is derived from the Province of Ragusa on the southeastern coast, where especially cherry tomato typologies are cultivated. Over the last decade, the Ragusa Province has registered a decrease both in terms of greenhouse tomato area and harvested production due to several structural problems that would require restructuring of the tomato supply chain. Thus, since recognition of real costs and profitability of tomato growing is a vital issue, b…
Planning Production Preparation Processesusing The Critical Chain Method
2017
This paper explains the usefulness of critical chain project management for planning production preparation processes. A synthesis of issues of project management and production preparation processes is presented, and a conceptual model of concurrent design processes using the critical chain method is developed. The proposed model of planning production preparation processes enables improving the effectiveness and economic efficiency of new product development. The main assessment indicators of efficient project management in production preparation are: shortening the preparation time of new product development, rational use of resources, and reducing the risk of failure. The proposed appro…