Investigation of strength recovery of recycled heat treated glass fibres through chemical treatments

The strength loss of thermally treated glass fibre (GF) at elevated temperature is well reported in literature. This phenomenon even occurs at short period of time such as 25 minutes. In the recycling technologies for composites, GFs are usually recovered by degradation of polymeric matrix with thermal and/or chemical treatments. Therefore thermal effect on the strength of GF is a significant factor when restricting the possibilities of recycling this material for a second life. This study reports on the strength of thermally treated commercial GF after acid treatment and silanization of the fibre surface to achieve a proper combination of treatments which may provide us with the ability to recover the mechanical properties of the heat treated GFs. It is thought that silane coupling agents can directly increase and recover the strength of GFs. Two factors associated with this recovery are the possibility of the sizing repairing the damage on the surface of the heat treated GFs and the reduction of the fibre-fibre friction in the bundle through lubricating effect. GF samples were heat treated at 4500C for 25 minutes and coated with silanes, applying different combinations of hydrochloric acid (HCl) and the two silanes used in this study, γ-Aminopropyltrimethoxy Silane (APS) and γ- Methacryloxypropyltrimethoxy Silane (MPS); these fibres were characterized by single fibre testing for strength. The results obtained demonstrated that the fibre strength improves slightly after combination of HCl and MPS treatment, and has a negative effect when the combination of HCl and APS was used. The surface deposition of silane on the surface of the fibre is also discussed using a Scanning Electron Microscope (SEM)

Regeneration of thermally recycled glass fibre for cost-effective composite recycling : Performance of composites based on PP and Recovered glass fibre

Due to economic and technical reasons, no recycling process for glass fibre composites has been commercialized on a large scale. Thermal recycling processes are promising in terms of potential for commercialization but the reinforcement potential of thermally recycled fibres is too low for the application in composites. In the present study, glass fibres were exposed to elevated temperatures prior to composite processing to imitate a thermal recycling process. The exposure of the fibres to elevated temperatures prior to composite processing caused a significant reduction of the mechanical properties of the composites. The heat treated fibres were regenerated with a post treatment. The regeneration of the glass fibres recovered the mechanical properties of the composites almost completely. Thus, this study shows that composites based on thermally recycled glass fibres have the potential to compete with composites based on ‘new’ glass fibres

Phosphoproteomics data classify hematological cancer cell lines according to tumor type and sensitivity to kinase inhibitors

This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

Logic Integer Programming Models for Signaling Networks

We propose a static and a dynamic approach to model biological signaling networks, and show how each can be used to answer relevant biological questions. For this we use the two different mathematical tools of Propositional Logic and Integer Programming. The power of discrete mathematics for handling qualitative as well as quantitative data has so far not been exploited in Molecular Biology, which is mostly driven by experimental research, relying on first-order or statistical models. The arising logic statements and integer programs are analyzed and can be solved with standard software. For a restricted class of problems the logic models reduce to a polynomial-time solvable satisfiability algorithm. Additionally, a more dynamic model enables enumeration of possible time resolutions in poly-logarithmic time. Computational experiments are included

A constitutive model for analyzing martensite formation in austenitic steels deforming at high strain rates

This study presents a constitutive model for steels exhibiting SIMT, based on previous seminal works, and the corresponding methodology to estimate their parameters. The model includes temperature effects in the phase transformation kinetics, and in the softening of each solid phase through the use of a homogenization technique. The model was validated with experimental results of dynamic tensile tests on AISI 304 sheet steel specimens, and their predictions correlate well with the experimental evidence in terms of macroscopic stress–strain curves and martensite volume fraction formed at high strain rates. The work shows the value of considering temperature effects in the modeling of metastable austenitic steels submitted to impact conditions. Regarding most of the works reported in the literature on SIMT, modeling of the martensitic transformation at high strain rates is the distinctive feature of the present paper.The researchers of the University Carlos III of Madrid are indebted to the Comunidad Autónoma de Madrid (Project CCG10-UC3M/DPI-5596)) and to the Ministerio de Ciencia e Innovación de España (Project DPI/2008-06408) for the financial support received which allowed conducting part of this work. The authors express their thanks to Mr. Philippe and Mr. Tobisch from the company Zwick for the facilities provided to perform the tensile tests at high strain rates

A constitutive model for analyzing martensite formation in austenitic steels deforming at high strain rates

This study presents a constitutive model for steels exhibiting SIMT, based on previous seminal works, and the corresponding methodology to estimate their parameters. The model includes temperature effects in the phase transformation kinetics, and in the softening of each solid phase through the use of a homogenization technique. The model was validated with experimental results of dynamic tensile tests on AISI 304 sheet steel specimens, and their predictions correlate well with the experimental evidence in terms of macroscopic stress–strain curves and martensite volume fraction formed at high strain rates. The work shows the value of considering temperature effects in the modeling of metastable austenitic steels submitted to impact conditions. Regarding most of the works reported in the literature on SIMT, modeling of the martensitic transformation at high strain rates is the distinctive feature of the present paper.The researchers of the University Carlos III of Madrid are indebted to the Comunidad Autónoma de Madrid (Project CCG10-UC3M/DPI-5596)) and to the Ministerio de Ciencia e Innovación de España (Project DPI/2008-06408) for the financial support received which allowed conducting part of this work. The authors express their thanks to Mr. Philippe and Mr. Tobisch from the company Zwick for the facilities provided to perform the tensile tests at high strain rates

Formative Assessment Framework Proposal for Transversal Competencies: Application to Analysis and Problem-Solving Competence

Purpose: In the last years, there is an increasing interest in the manner that transversal competences (TC) are introduced in the curricula. Transversal competences are generic and relevant skills that students have to develop through the several stages of the educational degrees. This paper analyses TCs in the context of the learning process of undergraduate and postgraduate courses. The main aim of this paper is to propose a framework to improve results. The framework facilities the student's training and one of the important pieces is undoubtedly that he has constant feedback from his assessments that allowing to improve the learning. An applying in the analysis and problem solving competence in the context of Master Degree in Advanced Engineering Production, Logistics and Supply Chain at the UPV is carried out. Design/methodology/approach: The work is the result of several years of professional experience in the application of the concept of transversal competence in the UPV with undergraduate and graduate students. As a result of this work and various educational innovation projects, a team of experts has been created, which has been discussing some aspects relevant to the improvement of the teaching-learning process. One of these areas of work has been in relation to the integration of various proposals on the application and deployment of transversal competences. With respect to this work, a conceptual proposal is proposed that has subsequently been empirically validated through the analysis of the results of several groups of students in a degree. Findings: The main result that is offered in the work is a framework that allows identifying the elements that are part of the learning process in the area of transversal competences. Likewise, the different items that are part of the framework are linked to the student's life cycle, and a temporal scope is established for their deployment. Practical implications: One of the most noteworthy practical implications is that the proposed framework includes a tool that allows a clear measurement of the student's evolution throughout his / her formative life cycle. In this way the student has a more consistent and robust vision of his / her training and the academic directors of the titles can have a vision of the impact of the decisions on the learning processes. Originality/value: The analysis of transversal competences is usually presented in the context of a subject. In this paper we propose an approach to cross-curricular competences but in the scope of the student's complete life cycle. The consideration of the entire formative process as well as the identification of the relevant elements that are part of this process are the most original aspects of the work.Peer Reviewe