Search results for "Plastics"
showing 10 items of 2724 documents
Mechanical Characterization of Polymers on a Nanometer Scale through Nanoindentation. A Study on Pile-up and Viscoelasticity
2007
The analysis of nanoindentation force curves collected on polymers through the common Oliver and Pharr procedure does not lead to a correct evaluation of Young’s modulus. In particular, the estimated elastic modulus is several times larger than the correct one, thus compromising the possibility of a nanomechanical characterization of polymers. Pile-up or viscoelasticity is usually blamed for this failure, and a deep analysis of their influences is attempted in this work. Piling-up can be minimized by indenting on a true nanometer scale, i.e., at penetration depth smaller than 200 nm. On the other side, it is common knowledge that fast indentations minimize the effect of viscoelasticity. How…
Kinetics of Anionic Living Copolymerization of Isoprene and Styrene Using in Situ NIR Spectroscopy: Temperature Effects on Monomer Sequence and Morph…
2019
The living anionic copolymerization of isoprene (I) and styrene (S) can afford a variety of different polymer microstructures that strongly depend on experimental parameters such as solvent, counte...
Pricing and hedging GDP-linked bonds in incomplete markets
2018
Abstract We model the super-replication of payoffs linked to a country’s GDP as a stochastic linear program on a discrete time and state-space scenario tree to price GDP-linked bonds. As a byproduct of the model we obtain a hedging portfolio. Using linear programming duality we compute also the risk premium. The model applies to coupon-indexed and principal-indexed bonds, and allows the analysis of bonds with different design parameters (coupon, target GDP growth rate, and maturity). We calibrate for UK and US instruments, and carry out sensitivity analysis of prices and risk premia to the risk factors and bond design parameters. We also compare coupon-indexed and principal-indexed bonds. F…
Recycling of plastics from packaging
1997
Plastic waste coming from the separate collection of packaging film was recycled and characterized. The material is a blend of low density and linear low density polyethylene and after recycling shows mechanical and rheological properties depending on the processing conditions and apparatus. High processing temperature and high residence times strongly enhance the degradation processes and reduce the mechanical properties, in particular the elongation at break. A possible use of this recycled plastic is for the production of low pressure pipes but the properties are lower than those of virgin pipe grade polyethylene. By introducing additives, like antioxidants, inert fillers and impact modi…
Effect of fillers on the properties of recycled polymers
2003
The main problems in post-consumer plastics recycling are due to the degradation undergone during lifetime and during processing steps. Moreover, for heterogeneous recycling, the incompatibility among the different polymeric phases give rise to secondary materials with low mechanical and thermomechanical properties. The properties-reprocessing relationships are an important tool for determining not only the properties of the recycled polymers but also the strategies to apply (processing conditions, stabilisers, fillers, compatibilizers, etc) in order to obtain recycled polymers with good mechanical properties. In this work the effect of adding inert fillers and modifier agents to recycled p…
Dextrans produced by lactic acid bacteria exhibit antiviral and immunomodulatory activity against salmonid viruses
2015
36 p.-7 fig.-1 tab.-1 fig. supl.
Classical and alternative pathways of mast cell activation.
2002
It has long since been recognized that mast cells are critical effectors of anaphylactic reactions, and the existence of these potentially hazardous cells has solely been justified due to their beneficial role in some infections with extracellular parasites. A novel understanding of mast cells as sentinels of the immune system has been made possible by taking advantage of mast cell-deficient mice in order to study the roles of mast cells in vivo and by detailed analyses of mast cell activation in vitro. Collectively, these experiments have revealed a variety of IgE-independent stimuli, which lead to the activation of mast cells as crucial initiators of an inflammatory response. Besides thei…
Market Polarization and the Phillips Curve
2021
The Phillips curve has flattened out over the last decades. We develop a model that rationalizes this phenomenon as a result of the observed increase in polarization in many industries, a process along which a few top firms gain an increasing share of their industry market. In the model, firms compete a la Bertrand and there is exit and endogenous market entry, as well as optimal up and downgrading of technology. Firms with larger market shares find optimal to dampen the response of their price changes, thus cushioning the shocks to their marginal costs through endogenous countercyclical markups. Thus, regardless of its causes (technology, competition, barriers to entry, etc.), the recent i…
PENGARUH MODAL USAHA DAN LAMA MELAUT, TERHADAP HARGA JUAL IKAN PADA PASAR TRADISIONAL SANGGENG MANOKWARI
2019
The purpose of this study was to measure the effect of venture capital (X1) and the long time at sea /time work hours (X2) for the offer price of fish (Y) in the tradisional sanggeng market manokwari, with 73 respondents chosen randomly and consisted of sellers and buyers in the sanggeng market.
 Data collection methods are done through interviews, (primary data) with a questionnaire and then carried out a questionnaire test and test the quality of the data, and then analyzed uiple linear regression.
 The result of research simultan eously or statistically partial variables X1 (venture capital) and variable X2 (long sea) significantly influence the higt selling price of …
Directed Interactions of Block Copolypept(o)ides with Mannose-binding Receptors: PeptoMicelles Targeted to Cells of the Innate Immune System
2015
Core-shell structures based on polypept(o)ides combine stealth-like properties of the corona material polysarcosine with adjustable functionalities of the polypeptidic core. Mannose-bearing block copolypept(o)ides (PSar-block-PGlu(OBn)) have been synthesized using 11-amino-3,6,9-trioxa-undecyl-2,3,4,6-tetra-O-acetyl-O-α-D-mannopyranoside as initiator in the sequential ring-opening polymerization of α-amino acid N-carboxyanhydrides. These amphiphilic block copolypept(o)ides self-assemble into multivalent PeptoMicelles and bind to mannose-binding receptors as expressed by dendritic cells. Mannosylated micelles showed enhanced cell uptake in DC 2.4 cells and in bone marrow-derived dendritic ce…