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Västerås, Sweden

Lee Y.-S.,Hanyang University | Jeong Y.B.,Corporate Research | Kim D.-W.,Hanyang University
Journal of Power Sources | Year: 2010

A hybrid composite membrane is prepared by electrospinning poly(vinylidene fluoride-co-chlorotrifluoroethylene) copolymer and Al2O3 powder with a microfibrous form on both sides of a polyethylene membrane. The composite membrane shows better thermal stability and wettability for liquid electrolyte solution than polyethylene membrane. The lithium-ion cell assembled with the composite membrane exhibits good capacity retention and high rate performance due to the effective encapsulation of the electrolyte solution in the cell and the adhesive properties of the swollen polymer towards electrodes. The hybrid composite membrane prepared by the electrospinning method is expected to be a separator with enhanced thermal stability and good cycling performance for application in lithium-ion batteries. © 2009 Elsevier B.V. All rights reserved. Source

Choi J.-A.,Hanyang University | Kim S.H.,Corporate Research | Kim D.-W.,Hanyang University
Journal of Power Sources | Year: 2010

Ceramic-coated separators are prepared by coating the sides of a porous polyethylene membrane with nano-sized Al2O3 powder and hydrophilic poly(lithium 4-styrenesulfonate) binder. These separators exhibit an improved thermal stability at high temperatures without significant thermal shrinkage. Due to the high hydrophilicity of the polymer binder and large surface area of the small ceramic particles, the separators show good wettability in non-aqueous liquid electrolytes. By using the ceramic-coated separators, lithium-ion cells composed of a carbon anode and a LiCoO2 cathode are assembled and their cycling performance is evaluated. The cells are proven to have better capacity retention than for cells prepared with polyethylene membrane. It is expected that the ceramic-coated separator in this study can be potential candidate as a separator for rechargeable lithium-ion batteries that require thermal safety and good capacity retention. © 2009 Elsevier B.V. All rights reserved. Source

Akerberg J.,ABB | Gidlund M.,ABB | Reichenbach F.,Corporate Research | Bjorkman M.,Malardalen University
IEEE International Conference on Emerging Technologies and Factory Automation, ETFA | Year: 2011

Contrary to the various theoretic publications on safety-critical communication over wireless, this paper will show the actual performance of safety-critical communication in a real plant with all its environmental influences. We used PROFIsafe as a functional safety profile on top of the WirelessHART protocol. Separately these technologies are widely used in industry for safety and wireless communication respectively, but it has never been shown that the combination of them is feasible for safety-critical communication. The main focus of this work is to measure and analyze the round-trip time and the bit error rate of the safety-critical communication in order to identify whether the certification requirements of PROFIsafe holds. We will show that it is technically feasible to run safety-critical data over wireless links. However, long round trip times and high noise in the channel at certain locations in the plant are unacceptable with respect to certification and need further investigations. © 2011 IEEE. Source

Sun L.,RWTH Aachen | Harjunkoski I.,Corporate Research | Castro P.,National Laboratory of Energy and Geology
Computer Aided Chemical Engineering | Year: 2013

In today's energy markets there is a growing effort in the alignment of the industrial sector to the power grid for the sake of efficient energy distribution and consumption. The steel making industry, as one of the most energy-intensive stakeholders, may play an important role in this context. In this paper, we use the Resource Task Network (RTN) in order to provide a generic modeling framework for scheduling problems under energy constraints. We study the impact of fluctuating electricity prices on the scheduling of operations in the steel plant and the economic profits that can be obtained from the steel plant's participation in the incentive-based iDSM program. © 2013 Elsevier B.V. Source

Chen X.,Chalmers University of Technology | Mantsch A.,Chalmers University of Technology | Hu L.,Chalmers University of Technology | Hu L.,Xian Jiaotong University | And 3 more authors.
IEEE Transactions on Dielectrics and Electrical Insulation | Year: 2014

This paper presents electrical treeing behavior in low density polyethylene (LDPE) and cross-linked polyethylene (XLPE) after exposure to thermal and DC electro-thermal ageing. Both the ageing and the treeing tests were performed by means of two different types of test objects with wire-plane electrode geometry. One type of the tested objects contained only wire electrode of 10 μm diameter, whereas in the other type the wire electrode was attached through a semiconducting tab. The ageing was performed at 80°C with and without 10 kV DC voltage of both polarities connected to the wire and lasted up to 800 hours. The AC electrical treeing tests were applied afterwards for detecting changes of material properties after the ageing. The results showed that the electrical tree inception voltage consistently decreased with increasing time of thermal exposure, whereas the applied DC electric stress had a negligible effect on the observed behavior. Similar effects were found in both the tested materials (LDPE and XLPE) though the object type also influenced the results. For the objects with semiconducting tab, a higher level of the scale parameter was registered because of shielding effect of the tab on the electric field strength at the wire electrode. It also yielded less number of trees growing in parallel at the electrode. The dominant effect of thermal stress on the ageing of LDPE was elucidated by using various analytical techniques, like differential scanning calorimetry, infrared spectroscopy, inductively coupled plasma optical emission spectrometry and oxidation induction time, and it is believed to mainly affect antioxidant content in the test objects. © 2014 IEEE. Source

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