Techno-Economic Modelling Of A Utility-Scale Redox Flow Battery System

A one-dimensional numerical model has been developed for redox flow battery (RFB) systems with bipolar flow-by electrodes, soluble redox couples, and recirculating batch operation. Overpotential losses were estimated from the Butler-Volmer equation, accounting for mass-transfer. The model predicted the variation in concentration and current along the electrode and determined the charge-discharge efficiency, energy density, and power density. The model was validated using data obtained from a pilot-scale polysulphide-bromine (PSB) system commercialized by Regenesys Technologies (UK) Ltd. The model was able to predict cell performance, species concentration, current distribution, and electrolyte deterioration for the Regenesys system. Based on 2006 prices, the system was predicted to make a net loss of 0.45 p kWh−1 at an optimum current density of 500 A m−2 and an energy efficiency of 64%. The economic viability was found to be strongly sensitive to the kinetics, capital costs, and the electrical energy price differential

Deep subcutaneous application of poly-L-lactic acid as a filler for facial lipoatrophy in HIV-infected patients

Introduction: Facial lipoatrophy is a crucial problem of HIV-infected patients undergoing highly active antiretroviral therapy (HAART). Poly-L-lactic acid (PLA), provided as New-Fill(R)/Sculptra(TM), is known as one possible treatment option. In 2004 PLA was approved by the FDA as Sculptra(TM) for the treatment of lipoatrophy of the face in HIV-infected patients. While the first trials demonstrated relevant efficacy, this was to some extent linked to unwanted effects. As the depth of injection was considered relevant in this context, the application modalities of the preparation were changed. The preparation was to be injected more deeply into subcutaneous tissue, after increased dilution. Material and Methods: To test this approach we performed a pilot study following the new recommendations in 14 patients. Results: While the efficacy turned out to be about the same, tolerability was markedly improved. The increase in facial dermal thickness was particularly obvious in those patients who had suffered from lipoatrophy for a comparatively small period of time. Conclusion: With the new recommendations to dilute PLA powder and to inject it into the deeper subcutaneous tissue nodule formation is a minor problem. However, good treatment results can only be achieved if lipoatrophy is not too intense; treatment intervals should be about 2 - 3 weeks. Copyright (C) 2005 S. Karger AG, Basel

Shirt sponsorship by gambling companies in the English and Scottish Premier Leagues: global reach and public health concerns

While the nature of gambling practices is contested, a strong evidence base demonstrates that gambling can become a serious disorder and have a range of detrimental effects for individuals, communities and societies. Over the last decade, football in the UK has become visibly entwined with gambling marketing. To explore this apparent trend, we tracked shirt sponsors in both the English and Scottish Premier Leagues since 1992 and found a pronounced increase in the presence of sponsorship by gambling companies. This increase occurred at the same time the Gambling Act 2005, which liberalized rules, was introduced. We argue that current levels of gambling sponsorship in UK football, and the global visibility it provides to gambling brands, is a public health concern that needs to be debated and addressed. We recommend that legislators revisit the relationship between football in the UK and the sponsorship it receives from the gambling industry

Quantum Convolutional Neural Networks

We introduce and analyze a novel quantum machine learning model motivated by convolutional neural networks. Our quantum convolutional neural network (QCNN) makes use of only $O(\log(N))$ variational parameters for input sizes of $N$ qubits, allowing for its efficient training and implementation on realistic, near-term quantum devices. The QCNN architecture combines the multi-scale entanglement renormalization ansatz and quantum error correction. We explicitly illustrate its potential with two examples. First, QCNN is used to accurately recognize quantum states associated with 1D symmetry-protected topological phases. We numerically demonstrate that a QCNN trained on a small set of exactly solvable points can reproduce the phase diagram over the entire parameter regime and also provide an exact, analytical QCNN solution. As a second application, we utilize QCNNs to devise a quantum error correction scheme optimized for a given error model. We provide a generic framework to simultaneously optimize both encoding and decoding procedures and find that the resultant scheme significantly outperforms known quantum codes of comparable complexity. Finally, potential experimental realization and generalizations of QCNNs are discussed.Comment: 12 pages, 11 figures. v2: New application to optimizing quantum error correction codes, added sample complexity analysis, more details for experimental realizations, and other minor revision

Influence of Flow Field Design on Zinc Deposition and Performance in a Zinc-Iodide Flow Battery

Among the aqueous redox flow battery systems, redox chemistries using a zinc negative electrode have a relatively high energy density, but the potential of achieving high power density and long cycle life is hindered by dendrite growth at the anode. In this study, a new cell design with a narrow gap between electrode and membrane was applied in a zinc-iodide flow battery. In this design, some of the electrolyte flows over the electrode surface and a fraction of the flow passes through the porous felt electrode in the direction of current flow. The flow battery was tested under constant current density over 40 cycles, and the efficiency, discharge energy density, and power density of the battery were significantly improved compared to conventional flow field designs. The power density obtained in this study is one of the highest power densities reported for the zinc-iodide battery. The morphology of the zinc deposition was studied using scanning electron microscopy and optical profilometry. It was found that the flow through the electrode led to a thinner zinc deposit with lower roughness on the surface of the electrode, in comparison to the case where there was no flow through the electrode. In addition, inhibition of dendrite formation enabled operation at a higher range of current density. Ex situ tomographic measurements were used to image the zinc deposited on the surface and inside the porous felt. Volume rendering of graphite felt from X-ray computed tomography images showed that in the presence of flow through the electrode, more zinc deposition occurred inside the porous felt, resulting in a compact and thinner surface deposit, which may enable higher battery capacity and improved performance

The effect of non-uniform compression on the performance of polymer electrolyte fuel cells

The mechanical compression used in the construction of PEFCs improves effective current collection and gas sealing, however it results in structural deformation of the MEA, affecting reactant transport with adverse consequences for the electrochemical performance of the cell. The present study uses X-ray CT to characterise MEA under compression and determine effective properties of the porous domain. The comprehensive modelling approach couples a structural model of the MEA under compression to a multi-phase, non-isothermal electrochemical performance model. Liquid water saturation in the cathode domain that promotes mass transport losses is validated with neutron radiography. Here, the structural model considers the fuel cell stacking process at three compressions and highlights the non-uniform distribution of porosity and effective properties under non-uniform cell compression, affecting localised current distribution and water transport. An increase in compression showed a negligible effect on the performance in the activation region, the performance was marginally improved in the ohmic region and significantly affected in mass transport region, promoting cell flooding. The non-uniform compression effects are found to be important considerations for robust modelling studies as it increases the nonuniformity in localised current, temperature and flooding that would further alter the durability of the fuel cell

Guideline adherence in febrile children below 3 months visiting European Emergency Departments: an observational multicenter study

Febrile children below 3 months have a higher risk of serious bacterial infections, which often leads to extensive diagnostics and treatment. There is practice variation in management due to differences in guidelines and their usage and adherence. We aimed to assess whether management in febrile children below 3 months attending European Emergency Departments (EDs) was according to the guidelines for fever. This study is part of the MOFICHE study, which is an observational multicenter study including routine data of febrile children (0–18 years) attending twelve EDs in eight European countries. In febrile children below 3 months (excluding bronchiolitis), we analyzed actual management compared to the guidelines for fever. Ten EDs applied the (adapted) NICE guideline, and two EDs applied local guidelines. Management included diagnostic tests, antibiotic treatment, and admission. We included 913 children with a median age of 1.7 months (IQR 1.0–2.3). Management per ED varied as follows: use of diagnostic tests 14–83%, antibiotic treatment 23–54%, admission 34–86%. Adherence to the guideline was 43% (374/868) for blood cultures, 29% (144/491) for lumbar punctures, 55% (270/492) for antibiotic prescriptions, and 67% (573/859) for admission. Full adherence to these four management components occurred in 15% (132/868, range 0–38%), partial adherence occurred in 56% (484/868, range 35–77%). Conclusion: There is large practice variation in management. The guideline adherence was limited, but highest for admission which implies a cautious approach. Future studies should focus on guideline revision including new biomarkers in order to optimize management in young febrile children

Assisted reproduction in Hong Kong: Status in the 1990s

Information on assisted reproduction in Hong Kong for the period from January 1992 to December 1993 was collected from the three centres that offer assisted reproduction. Altogether, 912 treatment cycles of in vitro fertilisation and embryo transfer, 158 treatment cycles of gamete intrafallopian transfer, and 87 cycles of zygote intrafallopian transfer were initiated during this period. The delivery rates per cycle started were 8.4% for in vitro fertilisation, 29.1% for gamete intrafallopian transfer, and 13.8% for zygote intrafallopian transfer. During the same period, 233 cycles of replacement of frozen thawed embryos were completed with a delivery rate of 11.2% per cycle. Pregnancies were also achieved using oocyte donation and micromanipulation techniques.published_or_final_versio