Processing-Microstructure-Properties Relationships in Extrusion of Thermoplastics

2006 ◽  
Vol 514-516 ◽  
pp. 833-837 ◽  
Author(s):  
Olga S. Carneiro ◽  
Júlio C. Viana ◽  
João M. Nóbrega

In this work, a rectangular polypropylene profile was produced with several different extrusion conditions, in order to identify the most relevant processing variables determining its morphology and mechanical properties and to establish relationships between them. A Taguchi Design of Experiments (DOE) technique considering two levels for each variable (extrusion temperature, extrusion throughput, drawdown ratio and distance between the die and the cooling bath) defined the set of extrusions runs carried out. The resulting plastic profiles were characterized in terms of their microstructure and mechanical properties. It was concluded that the most significant processing variable determining the mechanical properties of the profiles is the extrusion temperature and that the drawdown ratio controls the degree of molecular orientation of the profile and, therefore, the extension of its shrinkage after heatiing.

2019 ◽  
Vol 70 (4) ◽  
pp. 359-367
Author(s):  
Masoud Shafie ◽  
Hamid Zarea-Hosseinabadi

This study was performed to use date palm rachis, as a low value bio-waste, in the manufacture of a high value added eco-friendly structural composite lumber. Taguchi design of experiments was applied to analyse the effect of raw material and product parameters on the mechanical properties of laminated strand lumber from date palm rachis. The results indicate that the composite exhibits similar or superior strength properties compared to solid lumber and engineered products from wood or other lignocellulosic material for building sector. Taguchi design of experiments was assessed as a powerful and cost effective technique to obtain optimal levels for maximizing the mechanical properties of the environmentally-friendly composite. Maximum values for the mechanical properties of date palm rachis-based LSL were obtained from a combination of 20 mm product thickness, 10 % resin content, 4mm strand thickness, and 850 kg/m3 product density. Product thickness with an 81.3 % contribution and strand thickness with an 80 % contribution have the highest effects on the flatwise stiffness and compression strength perpendicular to grain, respectively.


2021 ◽  
pp. 096739112110413
Author(s):  
Raminder Kaur ◽  
Mukesh Kumar

In the present study, Taguchi design of experiments (DOEs) L18 orthogonal array has been used for the investigation of the mechanical behavior of rigid polyurethane foam (RPUF) composites. The outcome of the process parameters such as polyol, filler, surfactant, catalyst, blowing agent, and anti-flaming agent on the mechanical properties, such as tensile, flexural, and compressive strengths and hardness (Shore D) of RPUF composites, has been examined, and the resulted data were analyzed by means of Taguchi design of experiments. The raw data for the average values of the mechanical properties and the signal-to-noise (S/N) ratio for each parameter were evaluated at three levels, and the analysis of variance (ANOVA) and optimum process parameters are determined. The confirmation experiments were performed for the validation of the improved performance and to measure the contribution of individual parameter on the responses. The confirmation experiments revealed the average tensile strength, average compressive strength, average flexural strength, and average hardness (Shore D) as 5.24 MPa, 6.37 MPa, 12.28 MPa, and 72.43, respectively, which fall within the 95% confidence interval of the anticipated optimum process parameters.


Toxins ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 588
Author(s):  
Laura von Berg ◽  
Daniel Stern ◽  
Jasmin Weisemann ◽  
Andreas Rummel ◽  
Martin Bernhard Dorner ◽  
...  

The detection of catalytically active botulinum neurotoxins (BoNTs) can be achieved by monitoring the enzymatic cleavage of soluble NSF (N-ethylmaleimide-sensitive-factor) attachment protein receptor (SNARE) proteins by the toxins’ light chains (LC) in cleavage-based assays. Thus, for sensitive BoNT detection, optimal cleavage conditions for the clinically relevant A–F serotypes are required. Until now, a systematic evaluation of cleavage conditions for the different BoNT serotypes is still lacking. To address this issue, we optimized cleavage conditions for BoNT/A–F using the Taguchi design-of-experiments (DoE) method. To this aim, we analyzed the influence of buffer composition (pH, Zn2+, DTT (dithiothreitol), NaCl) as well as frequently used additives (BSA (bovine serum albumin), Tween 20, trimethylamine N-oxide (TMAO)) on BoNT substrate cleavage. We identified major critical factors (DTT, Zn2+, TMAO) and were able to increase the catalytic efficiency of BoNT/B, C, E, and F when compared to previously described buffers. Moreover, we designed a single consensus buffer for the optimal cleavage of all tested serotypes. Our optimized buffers are instrumental to increase the sensitivity of cleavage-based assays for BoNT detection. Furthermore, the application of the Taguchi DoE approach shows how the method helps to rationally improve enzymatic assays.


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