The correlation between the capacity fade of LiFePO4 batteries and cycle life

A new model is developed by fitting the capacity of LiFePO$_4$ batteries, which can be used to investigate the relationship between capacity fade, state of health (SoH), electrochemical reactions and the number of cycles. The equation for the proposed model based on modified Thevenin circuit, Butler-Volmer kinetics and regression analysis consists of a constant term, a sine-exponential term and an exponential term. The constant term represents the rated capacity of a battery, while the sine-exponential term represents the variation in capacity in the active status and the exponential term represents the variation in capacity in the stable status. The model is divided into two parts. The first part is represented by the sine-exponential term, responsive to the activation of electrolyte and electrodes in the first 180 cycles; the second part can be described by the exponential term, estimating the capacity from cycle 180 to cycle 2000. In addition, the comparison between the model and mean absolute percentage error (mape) is able to predict the serious decay of capacity. The MAPE is only 0.47% for the tested battery. The proposed model also successfully estimates the capacity of a tested battery where the number of cycles is 2000 with the error of 0.90%. The results mean that the model is able to closely describe the correlation between capacity and the cycle numbers. References M. Zhao, G. Huang, W. Zhang, H. Zhang and X. Song, Electrochemical behaviors of limn1-xfexpo4$/$c cathode materials in an aqueous electrolyte with/without dissolved oxygen, Energy and Fuels 27 (2013), 2:1162-1167. doi:10.1021/ef301893b Y.-C. Wang, F.-M. Ni and T.-L. Lee, Hybrid modulation of bidirectional three-phase dual-active-bridge dc converters for electric vehicles, Energies 9 (2016), no. 7, 492. doi:10.3390/en9070492 A. H. N. Galapitage and P. Pudney, Scheduling electric vehicles with shared charging stations, ANZIAM Journal 57 (2016), 208. doi:10.21914/anziamj.v57i0.10443 T. Zhu, H. T. Min, Y. B. Yu, Z. M. Zhao, T. Xu, Y. Chen, X. Y. Li and C. Zhang, An optimized energy management strategy for preheating vehicle-mounted li-ion batteries at subzero temperatures, Energies 10 (2017), no. 2. doi:24310.3390/en10020243 K. M. Tsang and W. L. Chan, State of health detection for lithium ion batteries in photovoltaic system, Energ Convers Manage 65 (2013), 7-12. doi:10.1016/j.enconman.2012.07.006 Z. Rao, S. Wang, M. Wu, Z. Lin and F. Li, Experimental investigation on thermal management of electric vehicle battery with heat pipe, Energ Convers Manage 65 (2013), 92-97. doi:0.1016/j.enconman.2012.08.014 A. Nikolian, Y. Firouz, R. Gopalakrishnan, J.-M. Timmermans, N. Omar, P. van den Bossche and J. van Mierlo, Lithium ion batteries-development of advanced electrical equivalent circuit models for nickel manganese cobalt lithium-ion, Energies 9 (2016), no. 5, 360. doi:10.3390/en9050360 Z. Gao, C. Chin, W. Woo and J. Jia, Integrated equivalent circuit and thermal model for simulation of temperature-dependent lifepo_4 battery in actual embedded application, Energies 10 (2017), no. 1, 85. doi:10.3390/en10010085 S.-Y. Lee, W.-L. Chiu, Y.-S. Liao, K.-Y. Lee, J.-H. Chen, H.-J. Lin and K. Li, Modified empirical fitting of the discharge behavior of lifepo_4 batteries under various conditions, ANZIAM Journal textbf55 (2014), 368. doi:10.21914/anziamj.v55i0.8182 C.-Y. Chung, K.-Y. Lee, T.-J. Kuo, Z.-Y. Lin, S.-D. Wu, C. Fu, Mathematical fitting for the variation in capacity of lithium iron phosphate batteries corresponding to cycles, ANZIAM Journal 57 (2016), 291. doi:10.21914/anziamj.v57i0.10436 T. Zahid and W. Li, A comparative study based on the least square parameter identification method for state of charge estimation of a lifepo_4 battery pack using three model-based algorithms for electric vehicles, Energies 9 (2016), no. 9, 720. doi:10.3390/en9090720 T. Sasaki, Y. Ukyo and P. Novak, Memory effect in a lithium-ion battery, Nat Mater 12 (2013), no. 6, 569-575. doi:10.1038/nmat3623 B. R. Tiwari and M. M. Ghangrekar, Enhancing electrogenesis by pretreatment of mixed anaerobic sludge to be used as inoculum in microbial fuel cells, Energy $and$ Fuels 29 (2015), no. 5, 3518-3524. doi:10.1021/ef5028197 P. Bai and M. Z. Bazant, Charge transfer kinetics at the solid-solid interface in porous electrodes, Nat Commun 5 (2014), 3585. doi:10.1021/ef990039t A. Eddahech, O. Briat and J.-M. Vinassa, Determination of lithium-ion battery state-of-health based on constant-voltage charge phase, Journal of Power Sources 258 (2014), 218-227. doi:10.1016/j.jpowsour.2014.02.020 R. Castaing, Y. Reynier, N. 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Comparison of laparoscopic versus open surgery in a three-stage operation for obstructive left-sided colorectal cancer

AbstractBackgroundTreatment for obstructive left-sided colorectal cancer (OLCC) typically consists of a three-staged procedure. During the first stage, the obstruction is managed with diversion colostomy. Traditionally in the second stage, we perform open resection for the primary tumor. In this study, we evaluated the feasibility of laparoscopic resection of OLCC with diversion colostomy in terms of operative results and short-term outcomes.MethodsA total of 20 patients underwent laparoscopic resection for OLCC (study group), 48 patients underwent open resection for OLCC (control group 1), and 53 patients underwent laparoscopic resection for non-OLCC (control group 2). Afterwards, results from the procedures were obtained and clinical data were analyzed.ResultsThe operative time was significantly longer in the study group than in the control group 1 (153 minutes vs. 126 minutes, p = 0.041), and the length of hospitalization was shorter in the study group than in the control group 1 (5.3 days vs. 7.6 days, p = 0.032). Regarding the operative results and short-term outcomes, there were no significant differences between the study group and control group 2. Colostomy retraction was a specific morbidity which occurred in two patients of the study group.ConclusionLaparoscopic resection of OLCC with diversion colostomy is feasible. Abdominal cavity adhesion is only limited. We strongly recommend that laparoscopic resection should be performed at least 2 weeks after diversion colostomy, and the plastic rod should be left in place during the pneumoperitoneum to reduce the risk of colostomy retraction

Induced pluripotent stem cells and regenerative medicine

AbstractStem cells, a special subset of cells derived from embryo or adult tissues, are known to present the characteristics of self-renewal, multiple lineages of differentiation, high plastic capability, and long-term maintenance. Recent reports have further suggested that neural stem cells (NSCs) derived from the adult hippocampal and subventricular regions possess the utilizing potential to develop the transplantation strategies and to screen the candidate agents for neurogenesis, neuroprotection, and neuroplasticity in neurodegenerative diseases. In this article, we review the roles of NSCs and other stem cells in neuroprotective and neurorestorative therapies for neurological and psychiatric diseases. We show the evidences that NSCs play the key roles involved in the pathogenesis of several neurodegenerative disorders, including depression, stroke, and Parkinson’s disease. Moreover, the potential and possible utilities of induced pluripotent stem cells, reprogramming from adult fibroblasts with ectopic expression of four embryonic genes, are also reviewed and further discussed. An understanding of the biophysiology of stem cells could help us elucidate the pathogenicity and develop new treatments for neurodegenerative disorders. In contrast to cell transplantation therapies, the application of stem cells can further provide a platform for drug discovery and small molecular testing, including Chinese herbal medicines. In addition, the high-throughput stem cell-based systems can be used to elucidate the mechanisms of neuroprotective candidates in translation medical research for neurodegenerative diseases

Capturing Cognitive Fingerprints from Keystroke Dynamics

Conventional authentication systems identify a user only at the entry point. Keystroke dynamics can continuously authenticate users by their typing rhythms without extra devices. This article presents a new feature called cognitive typing rhythm (CTR) to continuously verify the identities of computer users. Two machine techniques, SVM and KRR, have been developed for the system. The best results from experiments conducted with 1,977 users show a false-rejection rate of 0.7 percent and a false-acceptance rate of 5.5 percent. CTR therefore constitutes a cognitive fingerprint for continuous. Its effectiveness has been verified through a large-scale dataset. This article is part of a special issue on security

Realization of Polarization Control in High-Order Harmonic Generation

The nature of high-order harmonic generation process limits the harmonics emission to linear polarization. In this paper, we review the recent progress to generate elliptically or circularly polarized high-harmonic EUV pulses. We further demonstrate how complete control of polarization state of isolated high-harmonic pulse can be realized today by noncollinear focusing of two driving pulses with identical ellipticity but counter-rotating helicity. This paper opens a path towards the study of the fastest dynamics--down to attosecond time scales--in circular dichroism of magnetic materials, chiral molecules, and electronic spin motion.Taiwan Ministry of Science and Technology; Academia Sinica; Junta de Castilla y León; Ministerio de Economía y Competitividad; Leonardo Grant for Researchers and Cultural Creators, BBVA Foundation; Ministerio de Ciencia, Innovación y Universidades for a Ramón y Cajal; European Social Fund; Ministerio de Educación, Cultura y Deporte

Evolution of carbapenem resistance in Acinetobacter baumannii: An 18-year longitudinal study from a medical center in northern Taiwan

BackgroundCarbapenem-resistant Acinetobacter baumannii has emerged as an important cause of nosocomial infections with high morbidity and mortality. The carbapenemases, especially class D carbapenem-hydrolyzing oxacillinases (CHDLs), play an important role, but the relationship between their prevalence trend and carbapenem resistance remains unclear.Materials and methodsBetween 1995 and 2012, we collected 667 isolates of A. baumannii from a single medical center in northern Taiwan. Pulsed-field gel electrophoresis (PFGE) was used to determine clonality. Antimicrobial susceptibility was determined. Carbapenemase genes and associated genetic structures were detected by polymerase chain reaction.ResultsIsolates were heterogeneous on PFGE. Susceptibility to carbapenem decreased steadily over the study period from 88.1% (2001–2003) to <25% (2010–2012), whereas the isolates remained susceptible to colistin (nearly 100%) and partially susceptible to tigecycline (80%). Starting in 2001, isolates carrying the ISAba1-blaOXA-51-like allele were consistently identified. Isolates containing the transposons Tn2006 or Tn2008 first appeared in 2007 with increasing carriage rates from 17.5% (2007–2009) to 50.0% (2010–2012). The IS1008-ΔISAba3-blaOXA-58-like, blaOXA-72 and metallo-β-lactamase genes were detected only sporadically. Isolates carrying CHDL genes were resistant to multiple drugs, including carbapenem, but remained susceptible to colistin (100.0%).ConclusionIncreased carbapenem resistance in A. baumannii may be caused by the increased prevalence of isolates containing the ISAba1-blaOXA-51-like allele and the transposons Tn2006 and Tn2008

Genomic Signatures of Human versus Avian Influenza A Viruses

Fifty-two species-associated amino acid residues were found between human and avian influenza viruses

Photothermal responsivity of van der Waals material-based nanomechanical resonators

Nanomechanical resonators made from van der Waals materials (vdW NMRs) provide a new tool for sensing absorbed laser power. The photothermal response of vdW NMRs, quantified from the resonant frequency shifts induced by optical absorption, is enhanced when incorporated in a Fabry-Perot (FP) interferometer. Along with the enhancement comes the dependence of the photothermal response on NMR displacement, which lacks investigation. Here, we address the knowledge gap by studying electromotively driven niobium diselenide drumheads fabricated on highly reflective substrates. We use a FP-mediated absorptive heating model to explain the measured variations of the photothermal response. The model predicts a higher magnitude and tuning range of photothermal responses on few-layer and monolayer NbSe$_{2}$ drumheads, which outperform other clamped vdW drum-type NMRs at a laser wavelength of $532\,$nm. Further analysis of the model shows that both the magnitude and tuning range of NbSe$_{2}$ drumheads scale with thickness, establishing a displacement-based framework for building bolometers using FP-mediated vdW NMRs.Comment: 7 pages, 4 figure