Nonlinear relaxation modulus via dual-frequency medium amplitude oscillatory shear (MAOS): General framework and case study for a dilute suspension of Brownian spheroids

2017 ◽  
Vol 61 (1) ◽  
pp. 67-82 ◽  
Author(s):  
Toni M. Bechtel ◽  
Aditya S. Khair
Author(s):  
Maria Nadia Postorino ◽  
Luca Mantecchini ◽  
Filippo Paganelli

Transport systems are important pollution sources, mainly in terms of greenhouse gases, noise and land consumption. To mitigate the problem and safeguard airport development at the same time, the involved stakeholders are fixing goals, priorities and duties in order to promote the sustainable development of the air transport industry at global level and the wellness of local communities as well. It is desirable to estimate airport noise and carbon impacts in order to suitably manage them and identify strategies in line with the concept of green economy. In this chapter, a general framework to identify optimal procedures and methods to evaluate the effectiveness of policies addressed to reduce airport impacts on the airport surroundings is proposed. The case study of the airport of Bologna is presented as an example of Transport Company that effectively operates to minimize its noise and carbon impacts. According to the proposed general framework, impacts and estimated costs to achieve the status of green company have been computed.


2018 ◽  
pp. 1133-1152
Author(s):  
Chrysi Chrysochou ◽  
Ioannis Iglezakis

This chapter describes the conflict between employers' legitimate rights and employees' right to privacy and data protection as a result of the shift in workplace surveillance from a non-digital to a technologically advanced one. Section 1 describes the transition from non-digital workplace surveillance to an Internet-centred one, where “smart” devices are in a dominant position. Section 2 focuses on the legal framework (supranational and national legislation and case law) of workplace surveillance. In section 3, one case study regarding wearable technology and the law is carried out to prove that national and European legislation are not adequate to deal with all issues and ambiguities arising from the use of novel surveillance technology at work. The chapter concludes by noting that the adoption of sector specific legislation for employees' protection is necessary, but it would be incomplete without a general framework adopting modern instruments of data protection.


2019 ◽  
Vol 31 (2) ◽  
pp. 021213 ◽  
Author(s):  
Luca Martinetti ◽  
Randy H. Ewoldt

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1257 ◽  
Author(s):  
Milad Kamkar ◽  
Soheil Sadeghi ◽  
Mohammad Arjmand ◽  
Ehsan Aliabadian ◽  
Uttandaraman Sundararaj

This study seeks to unravel the effect of carbon nanotube’s physical and chemical features on the final electrical and rheological properties of polymer nanocomposites thereof. Nitrogen-doped carbon nanotubes (N-CNTs) were synthesized over two different types of catalysts, i.e., Fe and Ni, employing chemical vapor deposition. Utilizing this technique, we were able to synthesize N-CNTs with significantly different structures. As a result, remarkable differences in the network structure of the nanotubes were observed upon mixing the N-CNTs in a polyvinylidene fluoride (PVDF) matrix, which, in turn, led to drastically different electrical and rheological properties. For instance, no enhancement in the electrical conductivity of poorly-dispersed (N-CNT)Ni/PVDF samples was observed even at high nanotube concentrations, whereas (N-CNT)Fe/PVDF nanocomposites exhibited an insulative behavior at 1.0 wt%, a semi-conductive behavior at 2.0 wt%, and a conductive behavior at 2.7 wt%. In terms of rheology, the most substantial differences in the viscoelastic behavior of the systems were distinguishable in the medium amplitude oscillatory shear (MAOS) region. The stress decomposition method combined with the evaluation of the elastic and viscous third-order Chebyshev coefficients revealed a strong intra-cycle elastic nonlinearity in the MAOS region for the poorly-dispersed systems in small frequencies; however, the well-dispersed systems showed no intra-cycle nonlinearity in the MAOS region. It was shown that the MAOS elastic nonlinearity of poorly-dispersed systems stems from the confinement of N-CNT domains between the rheometer’s plates for small gap sizes comparable with the size of the agglomerates. Moreover, the intra-cycle elastic nonlinearity of poorly-dispersed systems is frequency-dependent and vanished at higher frequencies. The correlation between the microstructure and viscoelastic properties under large shear deformations provides further guidance for the fabrication of high-performance 3D-printed electrically conductive nanocomposites with precisely controllable final properties for engineering applications.


Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 365
Author(s):  
Hyeong Yong Song ◽  
Lorenz Faust ◽  
Jinha Son ◽  
Mingeun Kim ◽  
Seung Joon Park ◽  
...  

Linear and nonlinear rheological properties of model comb polystyrenes (PS) with loosely to densely grafted architectures were measured under small and medium amplitude oscillatory shear (SAOS and MAOS) flow. This comb PS set had the same length of backbone and branches but varied in the number of branches from 3 to 120 branches. Linear viscoelastic properties of the comb PS were compared with the hierarchical model predictions. The model underpredicted zero-shear viscosity and backbone plateau modulus of densely branched comb with 60 or 120 branches because the model does not include the effect of side chain crowding. First- and third-harmonic nonlinearities reflected the hierarchy in the relaxation motion of comb structures. Notably, the low-frequency plateau values of first-harmonic MAOS moduli scaled with M w − 2 (total molecular weight), reflecting dynamic tube dilution (DTD) by relaxed branches. Relative intrinsic nonlinearity Q0 exhibited the difference between comb and bottlebrush via no low-frequency Q0 peak of bottlebrush corresponding to backbone relaxation, which is probably related to the stretched backbone conformation in bottlebrush.


2019 ◽  
Vol 30 (4) ◽  
pp. 1187-1220
Author(s):  
Francisco de Abreu Duarte

Abstract This article develops the concept of the monopoly of jurisdiction of the Court of Justice of the European Union (CJEU) through the analysis of the case study of the Investment Court System (ICS). By providing a general framework over the criteria that have been developed by the Court, the work sheds light on the controversial principle of autonomy of the European Union (EU) and its implications to the EU’s external action. The work intends to be both pragmatic and analytical. On the one hand, the criteria are extracted as operative tools from the jurisprudence of the CJEU and then used in the context of the validity of the ICS. This provides the reader with some definitive standards that can then be applied to future cases whenever a question concerning autonomy arises. On the other hand, the article questions the reasons behind the idea of the monopoly of jurisdiction of the CJEU, advancing a concept of autonomy of the EU as a claim for power and critiquing the legitimacy and coherence of its foundations. Both dimensions will hopefully help to provide some clarity over the meaning of autonomy and the monopoly of jurisdiction, while, at the same time, promoting a larger discussion on its impact on the external action of the EU.


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