scholarly journals Innovative Polyelectrolyte Treatment to Flame-Retard Wood

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2884
Author(s):  
Marie Soula ◽  
Fabienne Samyn ◽  
Sophie Duquesne ◽  
Véronic Landry
Keyword(s):  
Betula Alleghaniensis ◽  
Fire Retardancy ◽  
Reduced Pressure ◽  
Polyelectrolyte Complexes ◽  
New Approach ◽  
Sodium Phytate ◽  
Wood Construction ◽  
Low Weight ◽  
Wood Flooring ◽  
Wood Fire

Fire protection has been a major challenge in wood construction for many years, mainly due to the high flame spread risk associated with wood flooring. Wood fire-retardancy is framed by two main axes: coating and bulk impregnation. There is a growing need for economically and environmentally friendly alternatives. The study of polyelectrolyte complexes (PECs) for wood substrates is in its infancy, but PECs’ versatility and eco-friendly character are already recognized for fabric fire-retardancy fabrics. In this study, a new approach to PEC characterization is proposed. First, PECs, which consist of polyethyleneimine and sodium phytate, were chemically and thermally characterized to select the most promising systems. Then, yellow birch (Betula alleghaniensis Britt.) was surface-impregnated under reduced pressure with the two PECs identified as the best options. Overall, wood fire-retardancy was improved with a low weight gain of 2 wt.% without increasing water uptake.

scholarly journals New Approach for Hybrid Stenting of the Aortic Arch in Low Weight Children

2017 ◽  
Vol 3 (5) ◽  
pp. 147-151
Author(s):  
Subrata Kar ◽  
Ugonna Nwankwo ◽  
Manolis Georgievich Pursanov ◽  
Nabil Noureddin ◽  
Jamil Aboulhosn ◽  
...  
Keyword(s):  
Aortic Arch ◽  
New Approach ◽  
Low Weight

scholarly journals A Casting Mould for Rapid Tube Hydroforming Prototyping

2020 ◽  
Vol 4 (2) ◽  
pp. 29-33 ◽  
Author(s):  
Andrzej Kochański ◽  
Hanna Sadłowska
Keyword(s):  
New Technology ◽  
Tube Hydroforming ◽  
High Strength ◽  
Industrial Applications ◽  
Design Stage ◽  
Production Volume ◽  
New Approach ◽  
Low Weight ◽  
Mould Cavity ◽  
Single Part

In recent years, hydroforming has clearly expanded its range of industrial applications due to the growing interest in products which combine high strength with low weight. A current limitation of this technology was its economically justified production volume since the costs of producing tools eliminates the possibility of using hydroforming technology in prototype and single part production. The paper presents a freshly patented solution that allows for single part hydroforming. The new technology combines traditional hydroforming machines with a new approach to tool production. The new rapid die is made quickly and cheaply. The use of materials known from the production of foundry moulds causes the die to deform during hydroforming, but it is a controlled deformation. Thanks to the use of numerical modelling, the deformation of the mould cavity is predicted and taken into account at the design stage. The article presents important issues that need to be considered in the design of this innovative process.

scholarly journals Optimizing asteroid orbit computation forGaiawith normal points

2018 ◽  
Vol 620 ◽  
pp. A101
Author(s):  
Grigori Fedorets ◽  
Karri Muinonen ◽  
Thierry Pauwels ◽  
Mikael Granvik ◽  
Paolo Tanga ◽  
...  
Keyword(s):  
Independent Observation ◽  
Short Term ◽  
New Approach ◽  
Low Weight ◽  
Main Effect ◽  
The Common ◽  
Characteristic Features ◽  
The One ◽  
Orbit Computation

Context.In addition to the systematic observations of known solar-system objects (SSOs), a continuous processing of new discoveries requiring fast responses is implemented as the short-term processing ofGaiaSSO observations, providing alerts for ground-based follow-up observers. The common independent observation approach for the purposes of orbit computation has led to unrealistically large ephemeris prediction uncertainties when processing realGaiadata.Aims.We aim to provide ground-based observers with a cloud of sky positions that is shrunk to a fraction of the previously expected search area by making use of the characteristic features ofGaiaastrometry. This enhances the efficiency ofGaiaSSO follow-up network and leads to an increased rate of asteroid discoveries with reasonably constrained orbits with the help of ground-based follow-up observations ofGaiaasteroids.Methods.We took advantage of the separation of positional errors ofGaiaSSO observations into a random and systematic component. We treated theGaiaobservations in an alternative way by collapsing up to ten observations that correspond to a single transit into a single so-called normal point. We implemented this input procedure in theGaiaSSO short-term processing pipeline and the OpenOrb software.Results.We validate our approach by performing extensive comparisons between the independent observation and normal point input methods and compare them to the observed positions of previously known asteroids. The new approach reduces the ephemeris uncertainty by a factor of between three and ten compared to the situation where each point is treated as a separate observation.Conclusions.Our new data treatment improves the sky prediction for theGaiaSSO observations by removing low-weight orbital solutions. These solutions originate from excessive curvature of observations, introduced by short-term variations ofGaiaattitude on the one hand, and, as a main effect, shrinking of systematic error bars in the independent observation case on the other hand. We anticipate that a similar approach may also be utilized in a situation where observations from a single observatory dominate.

scholarly journals Minimizing the Total Weighted Waiting Times and Instability in a Rescheduling Problem with Dynamic Jobs Weight

2021 ◽  
Vol 11 (15) ◽  
pp. 7040
Author(s):  
Ayoub Tighazoui ◽  
Christophe Sauvey ◽  
Nathalie Sauer
Keyword(s):  
Waiting Times ◽  
Computing Time ◽  
Mixed Integer ◽  
Total Weighted Completion Time ◽  
New Approach ◽  
Hospital Environments ◽  
Efficiency Measures ◽  
Low Weight ◽  
Reactive Strategy ◽  
Weighted Completion Time

Thanks to smart technological tools, customers can at any moment create or modify their commands. This reality forced many production firms to become sensitive in rescheduling processes. In the literature, most of rescheduling problems consider classical efficiency measures. However, some existing works also consider stability as a measure for limiting the deviation from initial schedule. In this work, we aim to bridge the gap in existing works on rescheduling by investigating a new approach to measure simultaneously efficiency by the total weighted waiting times and stability by the total weighted completion time deviation. This combination of criteria is very significant in industrial and hospital environments. In this paper, a single machine rescheduling problem with jobs arriving over time is considered. A mixed integer linear programming (MILP) model is designed for this problem and an iterative predictive-reactive strategy for dealing with the online part. Numerical results show that, at each time the jobs are rescheduled, the low weight ones move forward. Consequently, a new concept consisting in increasing the jobs weight as function of time is established. The effect of this new conception is evaluated by the evolution of the maximum flowtime. Eventually, the computing time of the MILP resolution is studied to explore its limitations.

Cellular Structure of Halogen-Free Flame Retardant Foams Based on LDPE

2009 ◽  
Vol 28 (4) ◽  
pp. 249-268 ◽  
Author(s):  
S. Román-Lorza ◽  
M.A. Rodriguez-Perez ◽  
J.A. De Saja Sáez
Keyword(s):  
Flame Retardant ◽  
Cellular Structure ◽  
Inorganic Filler ◽  
Fire Retardancy ◽  
Compression Moulding ◽  
Closed Cell ◽  
Low Weight ◽  
Combustion Properties ◽  
Halogen Free ◽  
New Applications

Composites of LDPE/ATH (up to 70 wt.%) were foamed to create new materials with good fire retardancy properties and low weight, proving the feasibility of developing cellular structures when high levels of inorganic fillers are included. An experimental study was carried out to explore the effects of chemical composition on cellular structure as well as the effect of structure on their thermal, mechanical and combustion properties. Samples fabrication was carried out using an improved compression moulding route consisting of polymer compounding, precursor preparation and foaming under pressure. The polymer matrix consisted of low density polyethylene as well as certain amount of LLDPE-g-MAH as compatibilizer agent. The inorganic filler used was aluminium trihydroxide (ATH) ranging from 0 wt.% to 70 wt.%. Furthermore, azodicarbonamide (ADC) was used as chemical blowing agent. Foamed samples with cell sizes below 100 microns were produced. These samples showed similar fire retardancy than their solid precursors. The compatibilization was proved indispensable to achieve a good adhesion between mineral filler and polymer and to improve the cellular structure. The increase of the amount of filler has an interesting effect on the cellular structure, going from a closed-cell (at low contents) to an open-cell (at higher contents) cellular structure. As a result of this investigation, halogen-free flame retardant cellular materials were processed, leading to a notable reduction of material compared to the solid one and to new properties which can result in new applications.

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