2401. Characterization of mechanical and barrier properties of bacterial cellulose, glycerol and polyvinyl alcohol (PVOH) composite films with eco-friendly UV-protective propertiesPatricia Cazón, Gonzalo Velazquez, Manuel Vazquez, 2020, original scientific article Abstract: Highly flexible composite films based on bacterial cellulose, glycerol and polyvinyl alcohol (PVOH) with UV barrier properties were developed. The open nanoscale network of bacterial cellulose allowed to combine it with glycerol and polyvinyl alcohol by immersion. This procedure kept intact the bacterial cellulose structure. The interactions among bacterial cellulose, glycerol and PVOH were analyzed using scanning electron microscopy, infrared spectroscopy, thermogravimetry and differential scanning calorimetry. In general, the addition of PVOH reinforced the bacterial cellulose matrix, meanwhile glycerol showed a significant plasticizing effect. Formulations with PVOH and glycerol reached a maximum value of 49.89% of elongation and a good resistance to rupture of 13.78 MPa. The water vapour permeability ranged from 1.87·10−11 to 2.04·10−10 g/m s Pa. The UV-VIS spectral analysis showed that glycerol decreased the transmittance in the UV area and polyvinyl alcohol enhanced the transparency values of the samples in the VIS region. The transmittance in the UV-A, UV-B and UV- C areas for films based on bacterial cellulose with glycerol reached up to 5.59, 2.4 and 0.57%, respectively.
Keywords: Acetobacter xylinum, Tensile strength, Percentage of elongation at break, Young's modulus, Eco-friendly film
Published in RUNG: 14.12.2020; Views: 2217; Downloads: 0
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2402. Applications of Chitosan as Food Packaging MaterialsPatricia Cazón, Manuel Vazquez, 2019, review, book review, critique Abstract: The interest in biopolymers has increased due to the depletion of the fossil fuel reserve and the environmental impact caused by the accumulation of non-biodegradable plastic-based packaging materials. Many biopolymers have been developed from food waste products to reduce this waste and, at the same time, to
obtain new food packaging materials. Chitosan is thus an alternative to synthetic polymers, and a raw material for new materials. To assess the suitability of a material as a food packaging material, it is necessary to study their mechanical and permeability properties. Mechanical properties allow to predict the behaviour of films during transportation, handling and storage of packaged foods. Barrier properties play a key
role in maintaining the food product quality. Properties values depend on the type of chitosan used. Mechanical and barrier properties of pure chitosan films are suitable for food packaging and active packaging. These properties can be modified by combining chitosan with other components such as plasticizers, other polysaccharides, proteins and lipids. These combinations adapt the properties of the final polymer to the needs of
the food to extend its useful life, while maintaining quality properties of the food and the biodegradability of the polymer.
Chitosan displays antimicrobial activity against a wide range of foodborne filamentous fungi, yeast, and gram-negative and gram-positive bacteria. This antimicrobial property and film-forming capacity has made chitosan the reference polymer to develop active packaging with the ability to inhibit the growth of microorganisms and improve food safety. Regarding the optical properties, pure chitosan films in the visible range show high transmittance values, being optically transparent films. This
is an important parameter related to the acceptability of the films by the consumer. In addition, chitosan-based films exhibit remarkable UV absorbance, which allows to protect food from lipid oxidations induced by UV radiation.
Keywords: Film, Mechanical properties, Barrier properties, Antimicrobial, UV
protect, Active food packaging
Published in RUNG: 14.12.2020; Views: 2622; Downloads: 0
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2407. The Promise of Collective Authorship: Bela Balazs’s Move to the Soviet Union (1931-1946)Eszter Polonyi, unpublished conference contribution Abstract: Balazs belongs to a generation of Central and Eastern European critical thinker, cultural philosopher and writer that is often credited with exporting Marxist cultural analysis to North America, but about whom very little is known to English-language scholars. The fifteen years he spent in the Soviet Union are among the most undocumented of his career, even though this was when he wrote the text that would become his most widely-cited book, Theory of the Film. This paper examines Balazs’s decision to flee to the Soviet Union from Germany in 1931. While it has long been assumed that Balazs’s decision to move East rather than West—the route otherwise taken by colleagues of his such as Siegfried Kracauer, Michael Curtiz or Rudolf Arnheim—was due to commitments of a political nature, this paper evaluates Balazs’s options from the viewpoint of the scenarist’s rising importance within competing modes of film production. Pre-constituting a film by way of a plan, sketch or model, the scenario promised different types of leverage over production to capitalist and communist systems. Conceived of as a commodity blueprint in Hollywood, the scenario appeared as it was a means of enhancing the effectiveness of production and as a tool of capital, whereas, for Balazs at least, the scenario was a source of sensory and spiritual attunement between an assemblage of humans and machines. Understood as offering vision rather than oversight, collective authorship rather than collective control, the script appeared to complement the utopian arguments driving the Soviet film industry.
Keywords: film studies, industrial design, Soviet studies, authorship
Published in RUNG: 14.12.2020; Views: 2138; Downloads: 0
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2410. Do children derive exact meanings pragmatically? Evidence from a dual morphology languageFranc Marušič, Rok Žaucer, Amanda Saksida, Jessica Sullivan, Dimitrios Skordos, Longlong Wang, David Barner, 2021, original scientific article Abstract: Number words allow us to describe exact quantities like sixty-three and (exactly) one. How do we derive exact interpretations? By some views, these words are lexically exact, and are therefore unlike other grammatical forms in language. Other theories, however, argue that numbers are not special and that their exact interpretation arises from pragmatic enrichment, rather than lexically. For example, the word one may gain its exact interpretation because the presence of the immediate successor two licenses the pragmatic inference that one implies “one, and not two”. To investigate the possible role of pragmatic enrichment in the development of exact representations, we looked outside the test case of number to grammatical morphological markers of quantity. In particular, we asked whether children can derive an exact interpretation of singular noun phrases (e.g., “a button”) when their language features an immediate “successor” that encodes sets of two. To do this, we used a series of tasks to compare English-speaking children who have only singular and plural morphology to Slovenian-speaking children who have singular and plural forms, but also dual morphology, that is used when describing sets of two. Replicating previous work, we found that English-speaking preschoolers failed to enrich their interpretation of the singular and did not treat it as exact. New to the present study, we found that 4- and 5-year-old Slovenian-speakers who comprehended the dual treated the singular form as exact, while younger Slovenian children who were still learning the dual did not, providing evidence that young children may derive exact meanings pragmatically.
Keywords: Acquisition of quantity expressions, Acquisition of exactness, Pragmatics of grammatical number, Inferences on quantity, Dual, Slovenian
Published in RUNG: 13.12.2020; Views: 2486; Downloads: 0
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