Production and analysis of electrospun pa 6,6 and pva nanofibrous surfaces for filtration

Electrospun nanofibrous surfaces were produced by using two different polymers (PA 6,6 and PVA) at three different levels of polymer feeding rate (0.2, 0.6 and 1.0 ml/h, respectively) and three different levels of production time in electrospinning (5, 10 and 15 minutes, respectively) and the effect of polymer type, polymer feeding rate and production time was determined by analyzing unit weight and thickness of the nanofibrous membranes as well as fibre fineness and pore size distributions. The results showed that much finer fibres were produced by PA 6,6 polymer compare to PVA. The minimum average fibre fineness was 150.96 nm (by PA 6,6 polymer; 0.2 ml/h; 5 min.) while maximum fibre fineness was 243.43 nm (by PVA polymer; 0.6 ml/h; 15 min.). Similarly, the pore sizes of nanofibrous surfaces produced by PA 6,6 were smaller compare to the ones produced by PVA polymer. The results also indicated that coarser fibres were produced as the polymer feed rate and electrospinning time increased. In the second part of the work, composite structures were obtained by combining nanofibrous surfaces with PP non-woven material and their air permeability and filtration efficiency by using an aerosol having 0.2-0.33 mm diameter range were analyzed. The air permeability of PA 6,6 nanofibrous surfaces were much higher compare to the ones produced by PVA and quite high filtration efficiency (99.901 %) was obtained with PA 6,6 nanofibrous surfaces. Also, potential of these nanofibrous surfaces was evaluated by analysing chemical groups eliminated following their exposure to cigarette smoke which was chosen as a specific case study. © 2021 Inst. Nat. Cercetare-Dezvoltare Text. Pielarie. All rights reserved.NKUBAP.00.17, YL.13.05The authors would like to thank Tekirdağ Namık Kemal University, Scientific Research Project Unit as this work was supported by project number NKUBAP.00.17.YL.13.05. The authors also would like to thank 3M San. Tic. A. Ş. and Denge Kimya ve Tekstil San. Tic. A.Ş. (Tekirdağ, Turkey) for providing their facilities during some part of the tests

De-reifying technology transfer metrics: to address the stages and phases of TTO development

Book synopsis: Universities have become essential players in the generation of knowledge and innovation. Through the commercialization of technology, they have developed the ability to influence regional economic growth. By examining different commercialization models this book analyses technology transfer at universities as part of a national and regional system. It provides insight as to why certain models work better than others, and reaffirms that technology transfer programs must be linked to their regional and commercial environments. Using a global perspective on technology commercialization, this book divides the discussion between developed and developing counties according to the level of university commercialization capability. Critical cases as well as country reports examine the policies and culture of university involvement in economic development, relationships between university and industry, and the commercialization of technology first developed at universities. In addition, each chapter provides examples from specific universities in each country from a regional, national, and international comparative perspective. This book includes articles by leading practitioners as well as researchers and will be highly relevant to all those with an interest in innovation studies, organizational studies, regional economics, higher education, public policy and business entrepreneurship

From the experimental determination of stress-strain full fields during a bulge test thanks to 3D-DIC technique to the characterization of anisotropic Mullins effect

International audienceThe bulge test is usually mostly used to analyze equibiaxial tensile stress state at the pole of inflated isotropic membranes. Three-dimensional digital image correlation (3D-DIC) technique allows the determination of three-dimensional surface displacements and strain fields. A method is proposed to calculate from these experimental data the membrane curvature tensor at each surface point of the bulge specimen. Curvature tensor fields are then used to investigate axisymmetry of the test; in the axisymmetric case, membrane stress tensor fields are determined from meridional and circumferential curvatures combined with the measurement of the inflating pressure. Stress strain state is then known at any surface point which enriches greatly experimental data deduced from bulge tests. This method is then used to treat an experimental bulge test on a filled silicone rubber membrane. The results highlight that a global membrane with a very heterogeneous strain history is obtained , from equibiaxial behavior at the center of the membrane until a planar (pure) shear state at the periphery of the bulge. Next, different small tensile specimens are cut from the pre-stretched silicone membrane. Identical cyclic tensile tests are realized on all these specimens. The curves are compared and highlight the difference of the stress-softening according to the place of the cut specimen and according to its orientation with respect to the circumferential or meridional direction

Carbon-based torsional and tensile artificial muscles driven by thermal expansion

Conference on Electroactive Polymer Actuators and Devices (EAPAD) -- MAR 10-13, 2014 -- San Diego, CA[No Abstract Available]SPIE, Amer Soc Mech Engineer