Search results for "Mould"

Thermal Analysis, Mechanical and Rheological Behaviour of Melt Manufactured Polyethylene/Liquid Crystal Polymer Blends

2011

Modification of properties of conventional thermoplastics with thermotropic liquid crystal polymers, from one hand, allows decrease their viscosities, substantially facilitating processing conditions, and, from another hand, allows increase their exploitation properties. Orientation of the labile structure of liquid crystal polymer in extrusion or injection moulding causes specific reinforcement (so-called self-reinforcement) to occur in the blends containing liquid crystal polymer. Up to now the effect of self-reinforcement is mostly investigated in the blends, containing considerable amount of liquid crystal polymer. In this research the effect of minor amounts of liquid crystalline co-po…

Correlation between processability and properties of a high density polyethylene by a rheological approach

2002

The thermal-oxidative and thermal-mechanical stability of high density polyethylene (chromium based catalyst technology) was examined at many different temperatures using a rheological approach. The changes in molecular structure, which take place during processing, have been studied using a Clextral co-rotating twin-screw extruder in comparison with dynamic measurements performed with a rotational rheometer under definite conditions of temperature, strain and frequency and in presence of air. In order to evaluate the degradation response, an investigation of elastic modulus G' as a function of frequency ω on the residual sample after ageing has been carried out. The molecular weight increa…

Green composites for fertilizer controlled release produced by compression molding and FDM

2023

Excessive fertilization causes ecological problems due to leaching issues. To solve this problem and promote agriculture sustainability an innovative green composite for controlled release fertilizers was produced by adding NPK fertilizer flour to a biodegradable polymer with or without Opuntia Ficus Indica (OFI) particles. Six formulations were produced and employed for the fabrication of devices both for compression molding (CM) and fused deposition modeling (FDM). Both fillers displayed a good dispersion in the composites, excellent adhesion with the polymeric matrix and effectively acted as reinforcement. The decrease of NPK release rate (up to 30 days) was achieved using whole composit…

Cuerpos moldeables y vidas modulables: La invención del estado holísticamente saludable como bienestar (integral)

2020

The article argues ?from the Deleuzian concepts of society of control, moulding and modulation and the Rosean theory on the economization and medicalization of life? that the expansion of the concept of health in terms of integral and subjective well-being is the effect of a socio-historical shift in the way we relate to this signifier, and therefore to our bodies and ourselves. We use this interpretative network to analyze the effects that the biopsychosocial health paradigm has had in the context of aesthetic surgery and fitness practice. As a result, we see that the expansion of the concept of health has extended the domain of medicine into the spheres of personal care and physical appea…

Nitric oxide radicals are emitted by wasp eggs to kill mold fungi

2019

Detrimental microbes caused the evolution of a great diversity of antimicrobial defenses in plants and animals. Insects developing underground seem particularly threatened. Here we show that the eggs of a solitary digger wasp, the European beewolf Philanthus triangulum, emit large amounts of gaseous nitric oxide (NO⋅) to protect themselves and their provisions, paralyzed honeybees, against mold fungi. We provide evidence that a NO-synthase (NOS) is involved in the generation of the extraordinary concentrations of nitrogen radicals in brood cells (~1500 ppm NO⋅ and its oxidation product NO2⋅). Sequencing of the beewolf NOS gene revealed no conspicuous differences to related species. However,…

Water retention behaviour of compacted and reconstituted scaly clays

2020

The paper presents the results of an experimental research devoted to investigate the response to suction variations of a scaly clay in compacted and reconstituted conditions. Different experimental techniques (axis translation, vapour equilibrium, dew point psychrometer suction measurements) were combined in order to explore the water retention properties in a wide suction range (0 ÷ 110 MPa). Experimental results allowed to define the water retention domains for a constant reference void ratio, highlighting the significant role of the microstructure on the response of the investigated clays. In particular, the collected results showed that in the low-medium suction range, the peculiar mic…

The concept and the application of no-flow temperature (NFT) in simulation of injection moulding

2009

Processing and Properties of Biopolymer/Polyhydroxyalkanoates Blends

2011

In this paper, the processability and the performance of a biodegradable polymer, Mater-Bi, and of its blends with either a sample of poly (hydroxy alkanoates) (PHA) or with bacterial biomass containing PHAs were compared. Adding PHA or directly the biomass containing it allows improving the processability of the matrix. Moreover, the mechanical behaviour of the systems was compared considering two different preparation methods, namely compression and injection moulding. The injection moulded samples show poorer mechanical performances than those of the compression moulded systems. The impact strength significantly improves when PHA is added while it reduces when bacterial biomass is used i…

Le goût moisi-terreux du vin : contribution à la caractérisation cinétique et métabolique des moisissures associées à ce défaut organoleptique

2011

Some microorganisms that co-exist on the grapevine may have beneficial effects on the quality of wine whereas others may be at the origin of organoleptic deviations. In the last decade, several mouldy or earthy odors have been highlighted in various wine regions from France. (-)-geosmin was found to be the major compound responsible for this deviation, along with Botrytis cinerea and fungi belonging to the genus Penicillium, since they were frequently isolated from “earthy-musty” odor grapes. The extent of damage on the quality of wines, motivated our study on the caracterisation of grape rot fungi. First of all, the microflora of grapes from Burgundy vineyards was identified (morphological…

Production de styrene par Penicillium camemberti Thom

1989

National audience; The Celluloïd taste observed in some mould-ripened cheeses is bound to the presence of styrene in these cheeses. The accumulation of this molecule was only detected on cultures of some strains of Penicillium camemberti. It seems to be bound to a deregulation of oxidative metabolism of tneee strains.; L'apparition du goût de Celluloïd dans les fromages à pâte molle à croûte fleurie est liée à la présence de styrène dans ces fromages. L'accumulation de cette molécule n'est observée que sur des cultures de souches particulières de Penicillium camemberti. Elle semble liée à un dérèglement du métabolisme oxydatif de ces souches.