Combinatorial Performance Mapping of Near-NMC111 Li-ion Cathodes

A combinatorial library of twenty-three, phase pure, near-NMC111 (LiNi0·33Mn0·33Co0·33O2) compositions were synthesised and their electrochemical performance, was mapped (in lithium ion half-cells). Each of the 23 compositions was made in series, using a two-step process of 1) a rapid initial continuous hydrothermal precipitation, followed by 2) solid state lithiation. The 23 lithiated NMC samples were then subjected to analytical methods including electron microscopy (selected samples), Powder X-ray Diffraction and electrochemical tests in half cell Li-ion configurations versus Li metal. A sample with a Ni:Mn:Co (NMC) ratio of 39:28:33, revealed a specific capacity of 150 mA h g−1 at a C/20 rate, which was 63 and 43% greater capacity than NMC111 and NMC433 samples produced in this work, respectively. The sample with NMC ratio 47:25:28, showed the best capacity retention characteristics, retaining 70% of its C/20 capacity at 1C, after 40 cycles. Further analysis of all the samples by cyclic voltammetry and electrochemical impedance spectroscopy, allowed compositional mapping of diffusion coefficients. Overall, the mapping data revealed a gradual change of properties across compositional space, which has validated our combinatorial approach and allowed identification of the optimum performing near-NMC111 cathode materials

Incorporating collisions and resistance into the transition from field emission to the space charge regime

Advancements in microelectromechanical systems (MEMS) and microplasmas, particularly with respect to applications in combustion and biotechnology, motivate studies into microscale gas breakdown to enable safe system design and implementation. Breakdown at microscale deviates from that predicted by Paschen’s law due to field emission—the stripping of electrons from the cathode in the presence of strong surface field—and follows the Fowler-Nordheim (FN) law. As injected current increases at this length scale, electrons accumulate in the gap and FN electron emission becomes space charge limited, leading to the Child-Langmuir (CL) law at vacuum and the Mott-Gurney (MG) law at high pressure. While theoretical studies link CL to FN and CL to MG, none links all three to simultaneously assess the importance of pressure and external resistance (perturbation) on electron emission. This study extends existing theory to elucidate the transition between these regimes as a function of applied voltage, gap distance, electron mobility, and external resistance, and in particular, derives asymptotic equations illustrating the transitions between the three. It also demonstrates the presence of a triple point, where one theoretically encounters FN, CL, and MG at once, and characterizes the importance of gap pressure and distance on these regimes, especially when MG dominates at non-vacuum pressures. The sensitivity of the triple point to external resistance, representative of the effects of perturbations in system parameters on electron emission, receives special attention

The Deep Sea and Me: A Design-Based Research Study to Advance Public Literacy of the Deep Sea Using an Exhibit at a Public Marine Science Center

With growing populations and consumer demand, there has been a turn to the deep sea to meet our natural resource needs. The deep sea provides a range of benefits to humans—called ecosystem services—including carbon sequestration, fisheries, waste absorption and detoxification, and nutrient cycling, all of which are vital to life as we know it (Armstrong et al., 2012, Thurber et al., 2014). Barriers to effective management of deep-sea resources include (1) a lack of understanding by society of the benefits received from the deep sea and (2) how the public values it. To address this knowledge gap, this study utilized an iterative design-based research methodology to evaluate: (1) how to effectively use an exhibit at a science center to contribute to public literacy of the deep sea over the short and long-term and (2) how the public values deep-sea habitats. Three iterations of an exhibit entitled “The Deep Sea and Me” were evaluated and refined based on naturalistic observation, questionnaires, and interviews of visitors to ensure the exhibit’s short and long-term success as a tool to communicate policy-relevant deep-sea science. Exhibits containing video and interactive components succeeded in communicating deep-sea information that was retained by visitors during their visit and one month later. Visitors tended to agree with protection-oriented statements towards the deep sea. This study provides insight into how to effectively communicate policy-relevant information about the deep sea to an audience that has little to no prior knowledge of the ecosystem, yet who will be increasingly responsible for making use decisions of this habitat

Family support and cardiac rehabilitation: A comparative study of the experiences of South Asian and White-European patients and their carer's living in the United Kingdom

Background: Effective lifestyle modification facilitated by cardiac rehabilitation is known to reduce the occurrence of adverse coronary events and mortality. South Asians have poorer outcomes after a myocardial infarction than the general UK population, but little is known about their experiences of family support, cardiac rehabilitation and lifestyle change. Aims: To explore the nature of family support available to a sample of South Asian and White-European cardiac patients and to highlight similarities and differences between these groups with regard to cardiac rehabilitation and lifestyle modification. Methods: Using a qualitative approach, semi-structured interviews (in 1 of 6 languages) were conducted by researchers with; 45 South Asian patients and 37 carers and 20 White-European patients and 17 carers. Interviews were conducted in a home setting, up to eighteen months after discharge from hospital following myocardial infarction, coronary artery bypass surgery or unstable angina. Results: The main themes that emerged related to the provision of advice and information, family support and burden, dietary change and exercise regimes. Conclusions: Several cultural and ethnic differences were identified between patients and their families alongside similarities, irrespective of ethnicity. These may represent generic characteristics of recovery after a cardiac event. Health professionals should develop a cultural repertoire to engage with diversity and difference. Not every difficulty a person encounters as they try to access appropriate service delivery can be attributed to ethnic background. By improving services generally, support for South Asian populations can be improved. The challenge is to know when ethnicity makes a difference and mediates a person's relationship with service support and when it does not. (C) 2007 European Society of Cardiology. Published by Elsevier B.V. All rights reserved

High power TiO2 and high capacity Sn-doped TiO2 nanomaterial anodes for lithium-ion batteries

A range of phase-pure anatase TiO2 (∼5 nm) and Sn-doped TiO2 nanoparticles with the formula Ti1-xSnxO2 (where x = 0, 0.06, 0.11 and 0.15) were synthesized using a continuous hydrothermal flow synthesis (CHFS) reactor. Charge/discharge cycling tests were carried out in two different potential ranges of 3 to 1 V and also a wider range of 3 to 0.05 V vs Li/Li+. In the narrower potential range, the undoped TiO2 nanoparticles display superior electrochemical performance to all the Sn-doped titania crystallites. In the wider potential range, the Sn-doped samples perform better than undoped TiO2. The sample with composition Ti0.85Sn0.15O2, shows a capacity of ca. 350 mAh g−1 at an applied constant current of 100 mA g−1 and a capacity of 192.3 mAh g−1 at a current rate of 1500 mA g−1. After 500 charge/discharge cycles (at a high constant current rate of 382 mA g−1), the same nanomaterial anode retains a relatively high specific capacity of 240 mAh g−1. The performance of these nanomaterials is notable, particularly as they are processed into electrodes, directly from the CHFS process (after drying) without any post-synthesis heat-treatment, and they are made without any conductive surface coating

Continuous Hydrothermal Synthesis of Metal Germanates (M₂GeO₄; M=Co, Mn, Zn) for High-Capacity Negative Electrodes in Li-Ion Batteries

Nanosized metal germanates (M2GeO4; M = Co, Mn, Zn) are synthesized using a continuous hydrothermal flow synthesis process for the first time. The electrochemical properties of all samples as active materials for negative electrodes in Li‐ion half cells are explored. The galvanostatic and potentiodynamic testing is conducted in the potential range of 3.00–0.05 V versus Li/Li+. The results suggest that both alloying and conversion reactions associated with Ge contribute to the stored charge capacity; Zn2GeO4 shows a high specific capacity of 600 mAh g−1 (ten cycles at 0.1 A g−1) due to alloying and conversion reactions for both Ge and Zn. Mn2GeO4 is studied for the first time as a potential negative electrode material in a Li‐ion half cell; an excellent specific charge capacity of 510 mAh g−1 (10 cycles per 0.1 A g−1) is obtained with a significant contribution to charge arising from the conversion reaction of Mn to MnO upon delithiation. In contrast, Co2GeO4 only shows a specific capacity of 240 mAh g−1, after ten cycles at the same current rate, which suggests that cobalt has little or no benefit for enhancing stored charge in germanate

Epstein-Barr Virus Immediate-Early Protein BRLF1 Induces the Lytic Form of Viral Replication through a Mechanism Involving Phosphatidylinositol-3 Kinase Activation

Expression of the Epstein-Barr virus (EBV) immediate-early (IE) protein BRLF1 induces the lytic form of viral replication in most EBV-positive cell lines. BRLF1 is a transcriptional activator that binds directly to a GC-rich motif present in some EBV lytic gene promoters. However, BRLF1 activates transcription of the other IE protein, BZLF1, through an indirect mechanism which we previously showed to require activation of the stress mitogen-activated protein kinases. Here we demonstrate that BRLF1 activates phosphatidylinositol-3 (PI3) kinase signaling in host cells. We show that the specific PI3 kinase inhibitor, LY294002, completely abrogates the ability of a BRLF1 adenovirus vector to induce the lytic form of EBV infection, while not affecting lytic infection induced by a BZLF1 adenovirus vector. Furthermore, we demonstrate that the requirement for PI3 kinase activation in BRLF1-induced transcriptional activation is promoter dependent. BRLF1 activation of the SM early promoter (which occurs through a direct binding mechanism) does not require PI3 kinase activation, whereas activation of the IE BZLF1 and early BMRF1 promoters requires PI3 kinase activation. Thus, there are clearly two separate mechanisms by which BRLF1 induces transcriptional activation

High power Nb-doped LiFePO₄ Li-ion battery cathodes; pilot-scale synthesis and electrochemical properties

AbstractHigh power, phase-pure Nb-doped LiFePO4 (LFP) nanoparticles are synthesised using a pilot-scale continuous hydrothermal flow synthesis process (production rate of 6 kg per day) in the range 0.01–2.00 at% Nb with respect to total transition metal content. EDS analysis suggests that Nb is homogeneously distributed throughout the structure. The addition of fructose as a reagent in the hydrothermal flow process, followed by a post synthesis heat-treatment, affords a continuous graphitic carbon coating on the particle surfaces. Electrochemical testing reveals that cycling performance improves with increasing dopant concentration, up to a maximum of 1.0 at% Nb, for which point a specific capacity of 110 mAh g−1 is obtained at 10 C (6 min for the charge or discharge). This is an excellent result for a high power cathode LFP based material, particularly when considering the synthesis was performed on a large pilot-scale apparatus