1,720,962 research outputs found
Assessment of Arundo donax fibers for oil spill recovery applications
Full text linkIn the last years, natural fibers are increasingly investigated as an oil recovery system in order to overcome the oil spillage phenomena, thus preserving environment and aquatic life. In particular, lignocellulose-based fibers have recently been employed with promising results. In such a context, the aim of this paper is to assess the oil sorption capability of natural fibers extracted from the stem of the giant reed Arundo donax L., a perennial rhizomatous grass belonging to the Poaceae family that grows naturally all around the world thanks to its ability to tolerate different climatic conditions. Sorption tests in several pollutants and water as a reference were carried out. The fibers have absorption capacities that are about five to six times their weight. Depending on the high absorption kinetics, possible applicative interests can be identified. Eventually, depending on the fiber size, adsorption properties were related to the microstructure and morphology of Arundo donax fibers
Arundo donax fibers as green materials for oil spill recovery
No full textOil spillage is considered one of the most devastating forms of pollution, for its effect on the environment, particularly on aquatic life. This kind of disaster can impact in two ways, directly caused by the polluting spilled oil or due to the cleanup process. In fact, oil floating on water does not allow sunlight to pass through and its toxicity puts the life of aquatic animals at risk. Furthermore, other factors can also contribute to this damage. In fact, a wrong oil recovery system can add a further pollution level. Polymer sorbents used for the oil spill recovery, if not properly treated, increase the level of marine and ground pollution. For this reason, in the last years, green materials are increasingly studied and used for this purpose. Green adsorbents (such as lignocellulosic, fruits fibers) are recently employed with excellent results. Aim of this book chapter is the evaluation of the oil sorption properties of natural fibers extracted from the stem of the giant reed Arundo Donax L., a perennial rhizomatous grass belonging to the Poaceae family that grows naturally all around the world thanks to its ability to tolerate different climatic conditions
Hybrid clay mineral-carbon nanotube-PLA nanocomposite films. Preparation and photodegradation effect on their mechanical, thermal and electrical properties
No full textEffect of morphology of the filler on the electrical behaviour of poly(l-lactide) nanocomposites
No full textSurface Modified Arundo Donax Natural Fibers for Oil Spill Recovery
No full textThe use of green materials for oil recovery applications is the goal to be achieved to reduce the environmental impact of these essential processes. In this context, Arundo Donax L. is a plant known for its wide uses whose absorbent properties have been previously investigated. In this paper, the influence of silane surface treatment on the absorbent behavior of natural fibers extracted from the culms of this eco-friendly and cost-effective material was assessed. A close correspondence has been identified between the physical characteristics of the investigated oil and the fiber size, by means of microstructural and morphological analysis. Excellent results have been achieved with an absorption uptake of six to almost eight times its own weight, coupled with an improved selectivity of pollutant/water absorption, making the surface modified Arundo Donax fibers a potential effective material for oil recovery applications
Study of Intumescent Coatings Growth for Fire Retardant Systems in Naval Applications: Experimental Test and Mathematical Model
Full text linkOnboard ships, fire is one of the most dangerous events that can occur. For both military and commercial ships, fire risks are the most worrying; for this reason they have an important impact on the design of the vessel. The intumescent coatings react when heated or in contact with a living flame, and a multi-layered insulating structure grows up, protecting the underlying structure. In this concern, the aim of the paper is to evaluate the intumescent capacity of different composite coatings coupling synergistically modeling and experimental tests. In particular, the experiments have been carried out on a new paint formulation, developed by Colorificio Atria S.r.l., in which the active components are ammonium polyphosphate or pentaerythritol. The specimens were exposed to a gas-torch flame for about 70 s. The degree of thermal insulation of the coating was monitored by means of a thermocouple placed on the back of the sample. In order to get insights into the intumescent mechanism, experimental data was compared with the results of a mathematical model and a good agreement is detected. Furthermore, a predictive model on the swelling rate is addressed. The results highlight that all coatings exhibit a clear intumescent and barrier capacity. The best results were observed for coating enhanced with NH4PO3 where a regular and thick, porous char was formed during exposure to direct flame
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
In situ monitoring of moisture uptake of flax fiber reinforced composites under humid/dry conditions
Full text linkThe use of green materials such as natural fiber-reinforced composites represents an increasingly stringent prerogative in the future planning of industrial and non-industrial production. The optimization of these materials is the main aim of the current research, focused on the evaluation of the behavior of flax fiber reinforced composites exposed to isothermal adsorption and desorption cycles, at varying the partial pressure of water vapor (P/P0). For this purpose, the moisture uptake and the morphology changes of the composite material and their constituents were in situ monitored through a measurement protocol, by using a dynamic vapor sorption (DVS) analysis, coupled with an environmental scanning electron microscopy (ESEM) visual investigation. A dependence of moisture uptake and diffusivity on the composite morphology was clearly detected. In particular, no significant variation in the morphology of the specimen is noticed at low water vapor partial pressure (i.e., P/P0 up to 5.4%) due to the limited absorption capacity (i.e., lower than 1%). On the other hand, fibers morphology changes at increasing the partial pressure up to 25.1%, showing a sensitive increase in volume. This phenomenon becomes much more relevant for high relative humidity values (i.e., ~90%), reaching more than 6% of absorption capacity
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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