Search results for "stabilizer."

Reprocessing and restabilization of greenhouse films

2002

From the ecological and economical points of view, reprocessing of polyethylene greenhouse films is a promising solution to reduce discarded materials and to produce useful, or potentially useful, objects for service. Films exposed outdoors, however, show inferior mechanical properties and the melt processing worsens these properties. The addition of stabilizers and antioxidants to recycled plastic products prevents inherent thermal instabilities from occurring within the time frame of proper processing. In this study, we attempt to explore ways for improving product performance by the addition of four different additives when the recycled films undergo intensive shear processing. The proce…

Is melatonin an adjunctive stabilizer?

2012

UV-stabilisation of polystyrene-based nanocomposites provided by polyhedral oligomeric silsesquioxanes (POSS)

2012

Abstract The photo-ageing behaviour of Polyhedral Oligomeric SilSequioxane (POSS)-polystyrene (PS) nanocomposites has been investigated for the first time. POSS having different inorganic framework and pendant organic groups have been used in the PS nanocomposite preparation and the formulated films were subjected to accelerated weathering. Compared to pristine PS, the POSS-containing PS developed a lower level of carbonyl and hydroxyl groups as a function of the exposure time, indicating a significantly improved resistance of the nanocomposites to photo-degradation. The results suggest that all of the investigated POSS molecules play a protective role and may extend the in-use lifetime of …

Psychopharmacological treatment of bipolar disorder in Latin American

2011

Abstract Objective This study assessed the treatment preferences among Latin American psychiatrists for their bipolar disorder patients and if these preferences reflect the current guidelines. Methods We designed a survey comprised of 14 questions. All the questions were aimed at the treatment of bipolar I patients only. We distributed the survey by hand or e-mail to psychiatrists in eight different countries: Argentina, Brazil, Colombia, Costa Rica, Ecuador, Mexico, Peru and Venezuela. Between May 2008 and June 2009, we were able to gather 1143 surveys. Results As the initial choice of treatment for a bipolar patient who debuts with mania, 61.3% choose a combination of an atypical antipsyc…

Does Ligand Symmetry Play a Role in the Stabilization of DNA G-Quadruplex Host-Guest Complexes?

2014

In efforts to find agents with improved biological activity against cancer cells, recent years have seen an increased interest in the study of small molecules able to bind the deoxyribonucleic acid (DNA) when it assumes secondary structures known as G-quadruplexes (G4s) preferring them over the B form. Currently, several compounds reported in literature have already shown to be good candidates as G4s DNA stabilizers. Even though some specific features for the G4s affinity are known, such as a π-delocalized system able to stack at the top/end of a G-tetrad and positively charged substituents able to interact with the grooves, it is not clear yet what kind of structural features affect more t…

Digitaler Spektrumstabilisator für schnelle Analog-Digital-Konverter

1969

Abstract A versatile spectrum stabilizer is described, suitable for all ADC's with a digital parallel output and a pilot pulse at the end of the conversion. The stabilizer is especially developed for a 100 MHz ADC, but it is independent of the digitizing rate and the mode of conversion. The unit has a maximum cyclus time of 2 μsec and permits a parallel transfer rate of 500 kHz. The stabilizer corrects the effects of gain drift and is insensitive to statistical errors.

Multi-functional hindered amine light stabilizers-functionalized carbon nanotubes for advanced ultra-high molecular weight Polyethylene-based nanocom…

2015

Hindered Amine Light Stabilizer (HAS) molecules have been covalently linked on the outer surface of multi-walled carbon nanotubes (CNTs), and the so-obtained multi-functional fillers (HAS-f-CNTs) have been compounded with Ultra High Molecular Weight Polyethylene (UHMWPE) to get composite films. The success of the grafting reaction of the HAS molecules has been confirmed through spectroscopic and thermo-gravimetric analyses. Morphological analyses reveal a segregated microstructure, in which CNT-rich channels surround the polymer domains. This morphology results in improved mechanical properties and appreciable electrical conductive features. More importantly, the addition of only 1 wt.% of …

Interactive roll stabilization comparative analysis for large yacht: gyroscope versus active fins

2020

The problem of the active stabilization of ship motions is particularly important in the case of pleasure boats or in any case of passenger ships, since the commercial value of the ship is directly related to the comfort of the load transported in this case “people”, considered as stresses induced on them by the vessel movements, with particular attention to roll, given the ship geometric characteristics. Naval architects developed trough the years different solutions to reduce the roll of the ship, and consequentially to increase the passengers comfort, and the development of this solutions followed the progress of technology. Active fins have been the most used, but now the gyroscope solu…

The Effects of Structure on the One Dimensional Compression Behaviour of a Porous Calcarenite

2019

Human settlements built on weak rock deposits are often characterized by instabilities or collapse that may involve the underground cavities and consequently the above buildings. Underground calcarenite quarries in Marsala have been involved in a number of collapses that have seriously damaged numerous buildings. Unfortunately proper engineering solutions have not yet been identified according to the different and special cases and to the properties of this structured material. In order to investigate structure effects on the behaviour of the porous calcarenite of Marsala, this paper presents a comparison between the one dimensional compression behaviour of the intact rock and of the same w…

Influence of a sterically hindered amine on the photo-oxidation of low density/linear low density polyethylene blends

1990

Abstract Low density/linear low density polyethylene blends show a rate of degradation of the mechanical properties during photo-oxidation which increases with the content of the linear polymer. The use of a sterically hindered amine as UV stabilizer greatly improves the resistance of these blends to UV irradiation. The effectiveness of the stabilizer increases with the content of linear low density polyethylene.