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In this study, a new electrochemical impedance model to predict oxygen diffusion resistance in the cathode catalyst layer (CCL) and in the gas diffusion layer (GDL) of polymer electrolyte fuel cells (PEFCs) is proposed. The impedance model of the PEFC is validated with electrochemical impedance spectroscopy (EIS) measurements carried out in a single PEFC operated with oxygen diluted in nitrogen (nitrox) and diluted in helium (heliox) at different relative humidity (RH). The PEFC impedance model combines the impedance model for the CCL reported in the authors’ previous study with a diffusion impedance model for the GDL reported in the literature. The EIS measurements in the PEFC represent lumped parameters (total oxygen diffusion resistance R O 2 _ P E F C ) from the different layers comprising the PEFC. The impedance model ignores the effect of oxygen transport in the flow field plates on EIS measurements, as this effect is apparent on EIS measurements carried out in PEFCs with low oxygen stoichiometry. The results from this study demonstrate that the estimated oxygen diffusion resistances in the CCL and GDL are distributed in the total oxygen diffusion resistance R O 2 _ P E F C = R O 2 _ C C L + R O 2 _ G D L . This is demonstrated by analysing the EIS measurements carried out in the PEFC with nitrox and heliox as cathode gas reactants and neglecting oxygen transport resistance in either the CCL R O 2 _ P E F C ≈ R O 2 _ G D L or GDL R O 2 _ P E F C ≈ R O 2 _ C C L from the PEFC impedance model. It is possible to obtain a deeper understanding of the influence of the electrochemical mechanisms from the different layers comprising the PEFC on EIS measurements by combining fundamental theory and experimental measurements in a complimentary manner.

In this study, the change of electrochemical parameters during the gradual water accumulation of a polymer electrolyte fuel cell (PEFC) are estimated using electrochemical impedance spectroscopy (EIS) measurements and an impedance model based on electrode theory during a two-step oxygen reduction reaction (ORR). EIS measurements were carried out in a 5 cm2 H2/O2 PEFC operated under a dead-ended configuration of the gas reactants and during gradual accumulation of water. Kramers-Kronig evaluation demonstrated that the EIS measurements comply with stability and linearity properties and the inductive loops featured at low frequencies are attributed to electrochemical mechanisms within the PEFC and not to instability during gradual water accumulation. The impedance model has been reported in a previous study and simulates inductive loops at low frequencies which are attributed to platinum oxide formation during the ORR. The estimated parameters obtained from this EIS-modelling analysis can provide an insight into the decrease in PEFC performance during flooding conditions. A further qualitative analysis considering the effect of long-term water accumulation on the oxygen-reduction charge transfer resistance is discussed. It is possible to have an insight into the physical mechanisms of the PEFC by combining different experimental techniques and fundamental theory in a complimentary manner.

Based on fundamental electrochemical theory, an impedance model of a Nickel-Metal Hydride (NiMH) battery considering blocked-diffusion with frequency dispersion has been developed in this study. The impedance model accounts for electrochemical mechanisms during the decrease in the state of charge of a NiMH battery. The a.c. diffusion mechanisms in the NiMH battery during electrochemical impedance spectroscopy (EIS) tests can be modelled through a Warburg element considering blocked-diffusion with frequency dispersion. The Warburg element is analogous to a transmission line circuit comprised of distributed constant phase elements connected in parallel with resistors attributed to the resistance of diffusion processes. The NiMH impedance model is applied to EIS measurements carried out after discharging a NiMH battery pack. The impedance model can reproduce the straight-line EIS measurements of the NiMH battery represented in the low frequency range of the Nyquist plot. The change in slope of the straight-line EIS measurements at low frequencies can be related to nonhomogeneous electrode ion concentration and can be attributed to roughness of the NiMH electrode. This study has demonstrated that it is possible to gain an insight into the electrochemical processes of NiMH by combining fundamental theory of battery electrode and EIS measurements in a complementary manner.

Coercive practices, such as physical restraint, are used globally to respond to violent, aggressive and other behaviours displayed by mental health service users.1 A number of approaches have been designed to aid staff working within services to minimise the use of restraint and other restrictive practices. One such approach, the ‘REsTRAIN Yourself’ (RYS) initiative, has been evaluated in the UK. Rapid ethnography was used to explore the aspects of organisational culture and staff behaviour exhibited by teams of staff working within 14 acute admission mental health wards in the North West region of the English NHS. Findings comprise four core themes of space and place; legitimation; meaningful activity; and, therapeutic engagement that represent characteristics of daily life on the wards before and after implementation of the RYS intervention. Tensions between staff commitments to therapeutic relations and constraining factors were revealed in demarcations of ward space and limitations on availability of meaningful activities. The physical, relational and discursive means by which ward spaces are segregated prompts attention to the observed materialities of routine care. Legitimation was identified as a crucial discursive practice in the context of staff reliance upon coercion. Trauma‐informed care represents a potentially alternative legitimacy.

In this study, an impedance model of a polymer electrolyte fuel cell (PEFC) is considered to simulate inductive loops at low frequencies from electrochemical impedance spectroscopy (EIS) measurements carried out in an open-cathode PEFC stack. The new impedance model proposed in this study is derived from the hypothesis that water vapour transport in the cathode catalyst layer (CCL) yields the formation of inductive loops at low frequencies. The impedance model of the PEFC considers the impedance model of the CCL reported in a previous study and considers an analytical expression for the impedance of water vapour diffusion in the CCL. The developed PEFC impedance model is validated with EIS measurements featuring inductive loops at low frequencies and carried out in the individual cells comprising an open-cathode PEFC stack at two current densities. The parameters related to the impedance of water vapour diffusion simulate the inductive loops at low frequencies and simulate a change of the size of the impedance spectrum of the PEFC. Therefore, the formation of inductive loops at low frequencies can be attributed to not only water vapour transport, but also ionomer swelling/shrinking (hydration/dehydration) in the CCL. The impedance model can provide an insight into the relation between the trend of the inductive loops at low frequency and the change in the phase angle in the EIS measurements which can indicate the hydrated state in the membrane-electrode assembly of the individual cells of the open-cathode PEFC stack.

Background: The Advancing Quality Alliance (AQuA) is an NHS membership organisation based in the North West of England. AQuA has extensive experience of supporting member organisations with integration and latterly the development of an offer to understand how to apply quality improvement methodology to understand flows across care systems rather than at an organisational level. We will highlight the practical application of a model for understanding care systems from different perspectives “The 4 Arrows Model” and AQuA’s Whole System Flow programme structure. We have been working with our Lived Experience Affiliates, AQuA members and their populations using a person centred approach, to understand how the interplay between complexity, improvement science, leadership, coproduction and culture can support the successful application of QI methodology in the current context of care systems under intense pressure. Principle outcomes of this work are to create shared system purpose that understands and is enabled to address cultures, norms and values. The programme has 4 phases: 1. Diagnosing the system and making it visible to itself. 2. Sense checking the diagnostic findings whilst considering current local context. 3. Co-designing optimal pathways with the system, including patients/ service users and carers. 4. Implementing sustainable improvements with coproduced system measures. Consistent lines of enquiry: Person centeredness - staff, patients and community. Strengthening leadership and approacch to risk and behaviours Managing beliefs, expectations and priorities. Defining quality within the system using the Institute of Medicine (IoM) 6 domains of quality (Safe, Timely, Effective, Efficient, Equitable and Person centred) System impact assessment of poor and improved flows. Aims and Objectives: Understand the programme model and framework. Explore the methodology used to ensure a coproduced programme with people of lived experience. Consider local application. Discuss the key learning points from the diverse systems we’ve worked with so far. Format: 5 mins Introductions and objectives, Wendy Lewis, Programme Lead 20 minutes Enabling coproduction within an improvement programme beyond tokenism, Wendy Bell, Lived Experience Representative 20 minutes What are the benefits and solutions to embedding a commitment to coproduction within care systems? Table work/ group discussion 15 minutes An overview of the Whole System Flow Programme and key learning, Wendy L 20 minutes How could delegates apply the model and any identified learning to their own practice? Wendy L and Wendy B 10 minutes General feedback Target audience: This workshop will be of interest to people engaged in pathway redesign and the development of care systems aross organisational boundaries. It will be delivered to meet the needs of patients, community representatives as well as professionals within care systems and its leaders. Learnings/Take away: How AQuA developed an organisational approach to coproduction. How an appreciative approach to understanding systems with its staff and service users can create conditions for integration and improvement. How the 4 arrows model could be of benefit in strengthening leadership and managing beliefs, expectations and priorities.

Background\ud \ud Physical restraint is a coercive intervention used to prevent individuals from harming themselves or others. However, serious adverse effects have been reported. Minimising the use of restraint requires a multimodal approach to target both organisational and individual factors. The ‘Six Core Strategies’ developed in America, underpinned by prevention and trauma informed principles, is one such approach.\ud \ud \ud Objective\ud \ud An adapted version of the Six Core Strategies was developed and its impact upon physical restraint usage in mental health Trusts in the United Kingdom evaluated. This became known as ‘REsTRAIN YOURSELF. The hypothesis was that restraint would be reduced by 40% on the implementation wards over a six-month period.\ud \ud \ud Design\ud \ud A non-randomised controlled trial design was employed.\ud \ud \ud Setting\ud \ud Fourteen, adult, mental health wards from seven mental health hospitals in the North West of England took part in the study. Two acute care wards were targeted from all eligible acute wards within each site in negotiation with each Trust. The intervention wards (total n = 144 beds, mean = 20.1 beds per ward) and control wards (total n = 147 beds, mean = 21.0 beds per ward) were primarily mixed gender but included single sex wards also (2 female-only and 1 male-only in each group). All wards offered pharmacological and psychosocial interventions over short admission durations (circa 15 days) for patients with a mixture of enduring mental health problems.\ud \ud \ud Method\ud \ud As part of a pre and post-test method, physical restraint figures were collected using prospective, routine hospital records before and 6 months after the intervention. Restraint rates on seven wards receiving the REsTRAIN YOURSELF intervention were compared with those on seven control wards over three study phases (baseline, implementation and adoption).\ud \ud \ud Results\ud \ud In total, 1680 restraint incidents were logged over the study period. The restraint rate was significantly lower on the intervention wards in the adoption phase (6.62 events/1000 bed-days, 95% CI 5.53-7.72) compared to the baseline phase (9.38, 95% CI 8.19-10.55). Across all implementation wards there was an average reduction of restraint by 22%, with some wards showing a reduction of 60% and others less so (8%). The association between ward type and study phase was statistically significant.\ud \ud \ud Conclusion\ud \ud In conclusion, it is possible that reductions in the use of physical restraint are achievable using a model such as the Six Core Strategies. This approach can be adapted for global settings and changes can be sustained over time with continued support.

© 2019 John Wiley & Sons Ltd. What is known on the subject?: Mental health nursing in the UK and other countries faces an acute workforce crisis. Safe staffing levels are called for, and in some jurisdictions have been legislated for. The evidence base linking staffing levels and patient outcomes is limited. Staffing levels are implicated in adverse experiences of service users and staff within mental health ward settings, and they might contribute to levels of violence and aggression and the application of restrictive practices, such as physical restraint but there is limited research evidence to support this. Programmes such as Safewards, No Force First, the Engagement Model and the Six Core Strategies can reduce the use of restrictive practices. What does this paper add to existing knowledge?: Staffing levels on acute mental health wards appeared crucial in the implementation of a restraint minimization project. Both staff and service users implicate insufficient staffing for deficiencies in the relational elements of care, such as lack of face-to-face contact between nurses and service users. Similarly, staffing levels are associated with perceived problems in the cause of violence and aggression and responses to it. Despite successes in minimizing restrictive practices in this project, difficulties implementing alternative forms of practice that would reduce use of physical restraint, such as de-escalation, were also attributed to staffing levels. There is an irony that a project concerned with safety itself provoked concern over safe staffing levels. What are the implications for practice?: Efforts to reduce restrictive practices will be hampered without adequate staffing levels. Restrictive practices may justifyably be framed as an employment relations matter. Organisations and policy makers ought to address environmental, contextual and resourcing factors, rather than identify problems exclusively in terms of perceived aberrant behaviour of staff or service users. Abstract: Introduction Safe staffing and coercive practices are of pressing concern for mental health services. These are inter-dependent, and the relationship is under-researched. Aim To explore views on staffing levels in a context of attempting to minimize physical restraint practices on mental health wards. Findings emerged from a wider data set with the broader aim of exploring experiences of a restraint reduction initiative. Methods Thematic analysis of semi-structured interviews with staff (n = 130) and service users (n = 32). Results Five themes were identified regarding how staffing levels impact experiences and complicate efforts to minimize physical restraint. We titled the themes—“insufficient staff to do the job”; “detriment to staff and service users”; “a paperwork exercise: the burden of non-clinical tasks”; “false economies”; and, “you can't do these interventions.”. Discussion Tendencies detracting from relational aspects of care are not independent of insufficiencies in staffing. The relational, communicative and organizational developments that would enable reductions in use of restraint are labour intensive and vulnerable to derailment by insufficient and poorly skilled staff. Implications for practice Restrictive practices are unlikely to be minimized unless wards are adequately staffed. Inadequate staffing is not independent of restrictive practices and reduces access to alternative interventions for reducing individuals’ distress.

In this study, an analytical mathematical expression to simulate the low frequency impedance spectrum that represents the gas diffusion layer (GDL) and air channel of a proton-exchange membrane fuel cell (PEMFC) has been developed. The analytical expression considers the impedance response of the GDL with oxygen depletion in the air channel/GDL interface. Parameters of the finite-length Warburg impedance (ZW) reported in the literature and estimated from EIS measurements carried out in a PEMFC at different oxygen stoichiometry are considered as a base-line to simulate the GDL-channel impedance spectrum. The results demonstrate that non-stationary depletion of oxygen at the air channel/GDL interface during AC conditions yields the formation of a second loop on the GDL-channel impedance spectrum at low frequencies. In addition, it is demonstrated that the contribution of the AC current amplitude increases the second loop of the GDL-channel impedance spectrum and drifts the GDL-channel impedance spectrum away from its steady-state value which is related to the real component of the impedance response as the frequency is approaching zero. The resulting analytical expression of the GDL-channel impedance is analogous to the general mathematical expression of the finite-length Warburg component. The developed GDL-channel impedance model can simulate and separate the contribution of the impedance response of the GDL from the impedance response associated to oxygen depletion in the channel/GDL interface. This developed model could support other studies focusing on the estimation of diffusion parameters of the GDL from EIS measurements carried out in PEMFCs at different operating conditions.

In this study, an impedance model based on electrochemical theory of platinum oxide formation has been developed and combined with the impedance model based on hydrogen peroxide formation during the oxygen reduction reaction (ORR) and reported in a previous study to characterise inductive loops in impedance spectra of polymer electrolyte fuel cells (PEFCs). To validate the theoretical treatment, the simulated frequency response predicted by the theoretical model is compared against electrochemical impedance spectroscopy (EIS) measurements carried out in an open-cathode 16 cm2 H2/air PEFC stack at three different current densities. The results show that neither model in isolation (hydrogen peroxide nor platinum oxide models) can accurately reproduce the inductive loops in the EIS measurements at low frequencies. By deriving a model considering kinetics of hydrogen peroxide and platinum oxide formation, it is possible to reproduce the inductive loops at low frequencies and to estimate the DC polarisation resistance related to the slope of the polarisation curve as frequency reaches zero during EIS. This study demonstrates that different mechanisms that cause PEFC degradation and low performance could be manifested in EIS measurements simultaneously. The resulting model could support other electrochemical techniques to quantify the rates of hydrogen peroxide and platinum oxide formation during the ORR that limit the performance of PEFCs.

Purpose – The purpose of this paper is to improve the quality of monitoring of risk factors that predict the likelihood of people with severe mental illness (SMI) developing cardiovascular disease (CVD), diabetes and obesity, major contributors to poor physical health and risk of premature mortality. Design/methodology/approach – The first phase of the AQuA “Don’t just screen-intervene” initiative supported five specialised community-based Early Intervention for Psychosis services in North West England to assess the effectiveness of monitoring of cardiometabolic risk in their patients using standards derived from the Lester Positive Cardiometabolic Health Resource, a nationally acknowledged framework for people with psychosis receiving antipsychotic medication. The initial findings formed the basis for a quality improvement programme which ran from November 2012 until May 2013. Findings – By the end of a six month quality improvement programme the likelihood of a patient receiving a comprehensive cardiometabolic risk screening (evidenced by recorded measurement of body mass index or waist circumference, blood pressure, blood glucose and lipid profile, assessment of smoking status and enquiry of relevant family history) had increased from 10 to between 63 and 80 per cent. Research limitations/implications – Cardiometabolic risk monitoring from the onset of psychosis and its treatment can be improved utilising quality improvement methodology in real-world specialist mental health services. Earlier identification and treatment of risk factors that predict higher rates of obesity, diabetes and SMI may help people with SMI avoid life-restricting and life-shortening physical disorders. Practical implications – Given the National Audit of Schizophrenia findings of inadequate screening in those with established SMI alongside evidence that CVD risk can emerge early in the course of psychosis, a group of early intervention in psychosis services in North West England decided to examine this aspect of their routine clinical practice. This service evaluation describes the effectiveness of a quality improvement programme based on the Lester Positive Cardiometabolic Health Resource (referred to as Lester resource henceforth) to improve the effectiveness of monitoring of risk factors that predict the likelihood of people experiencing psychosis and schizophrenia developing CVD diabetes and obesity. Social implications – A combination of social disadvantage and unhealthy lifestyles, adverse cardiometabolic impacts of antipsychotic medication and inequitable access to physical healthcare combine to put people with SMI at particular risk from CVD, the single biggest cause of premature death, and much more common than suicide (Brown et al., 2010). Despite higher rates of potentially modifiable CVD risk factors (De Hert et al., 2009) people with SMI appear to be missing out on opportunities to actively prevent conditions like CVD and diabetes compared to the general population. Originality/value – People with SMI such as schizophrenia die 15-20 years earlier on average than the general population. Around 20 per cent of premature deaths can be explained by suicide and injury, but the remainder arise from a variety of natural causes such as CVD, chronic obstructive pulmonary disorder and certain cancers and infections (Nordentoft et al., 2013). The authors worked with five mental health trusts in the North West of England covering a sample of over 500 cases within early intervention services.

The use of the Blocked-diffusion Warburg (BDW) impedance within electrochemical impedance spectroscopy (EIS) measurements can unveil diffusion properties of the electroactive material of modern batteries at different states-of-charge. The impedance response of the BDW comprises a diffusion response of charge carriers through a short-diffusion distance (e.g. the solid-phase in electroactive material of battery electrodes) and a capacitive response due to accumulation of charge carriers in a blocked-interface (e.g. impermeable current collector of a thin film electrode). This study has developed a mathematical expression based on the Newton-Raphson iteration method to calculate the frequency and time constant during the transition from diffusion to capacitive response in the BDW impedance. The mathematical procedure to calculate the frequency during the diffusion-capacitive transition response in the BDW has been written in a script in Matlab® software and is applied to BDW impedance responses reported in previous studies and extracted from EIS measurements in Li-ion and NiMH batteries. This study demonstrates that the time constant during the transition from diffusion to capacitive response in the BDW differs from the characteristic time constant commonly represented in the BDW mathematical expression. The characteristic time constant represented in the BDW mathematical expression is related to the rate of accumulation of charge carriers in the blocked-interface of the electrode. On the other hand, the time constant during the transition from diffusion to capacitance responses in the BDW impedance can be related to diffusion properties in solid-phase particles with heterogeneous size distribution in the electroactive material of modern battery electrodes.

In this study, an impedance model represented as an equivalent electrical circuit (EEC) and comprised of a transmission line circuit and a frequency dispersion Warburg component is developed for the study of the electrochemical impedance spectroscopy (EIS) of Li-ion batteries. The model considers the impedance response of a porous cathode electrode comprised of solid particles surrounded by solution. Theory of diffusion of charge carriers in the solid and solution phases of the cathode composite electrode has been considered in the impedance model. The simulated impedance response predicted by the impedance model is compared with EIS measurements carried out in a Li Po battery pack. In addition, a theoretical comparison between the simulated EIS response from the developed model with the simulated impedance response of an EEC representing a Li-ion battery and reported in the literature is carried out as well. The effect of increasing and decreasing the cathodic diffusion distance of lithium ions across the solution and solid phases on the Nyquist impedance complex-plot is simulated. The impedance model is able to decouple diffusion mechanisms in the solid and solution phases of the cathode electrode represented at different frequencies of the Nyquist complex-plot. The results show that the impedance model can provide an insight into the different electrochemical mechanisms of the Li-ion battery represented in the Nyquist complex impedance plot at different frequencies. The model could assist the understanding of the different phenomenological processes in the electrode during the decrease of state of charge of Li-ion batteries using EIS.

International efforts to minimize coercive practices include the US Six Core Strategies© (6CS). This innovative approach has limited evidence of its effectiveness, with few robustly designed studies, and has not been formally implemented or evaluated in the UK. An adapted version of the 6CS, which we called ‘REsTRAIN Yourself’ (RY), was devised to suit the UK context and evaluated using mixed methods. RY aimed to reduce the use of physical restraint in mental health inpatient ward settings through training and practice development with whole teams, directly in the ward settings where change is to be implemented and barriers to change overcome. In this paper we present qualitative findings that report on staff perspectives on the impact and value of RY following its implementation. Thirty-six staff participated in semi-structured interviews with data subject to thematic analysis. \ud \ud Eight themes are reported that highlight perceived improvements in every domain of the 6CS after RY had been introduced. Staff reported more positively on their relationships with service users and felt their attitudes towards the use of coercive practices such as restraint were changed; the service as a whole shifted in terms of restraint awareness and reduction; and new policies, procedures and language were introduced despite certain barriers. These findings need to be appreciated in a context wherein substantial reductions in the use of physical restraint was proven possible, largely due to building upon empathic and relational alternatives. However, yet more could be achieved with greater resourcing of inpatient care.

In this study, an impedance model based on electrochemical theory considering hydrogen peroxide formation during a two-step oxygen reduction reaction (ORR) in polymer electrolyte fuel cells (PEFCs) has been developed. To validate the theoretical treatment, electrochemical impedance spectroscopy (EIS) measurements were carried out in an open-cathode 16 cm 2 H 2 /air PEFC stack. The results show that inductive loops at low frequencies of the impedance spectra are attributed to mechanisms related to hydrogen peroxide formation during ORR. The results also demonstrate that the mechanisms during consumption of hydrogen peroxide to form water (second-step in ORR) can be the dominating process for losses in the PEFC compared to the mechanisms during oxygen consumption to form hydrogen peroxide (first-step in ORR). Oxygen transport limitations can be a result of hydrogen peroxide adsorbed onto the surface of the electrode which reduces the number of active sites in the cathode catalyst layer for oxygen to react. This study could support results from other experimental techniques to identify hydrogen peroxide formation during the ORR that limit the performance of PEFCs.

Based on fundamental electrochemical theory, an impedance model for analysis of electrochemical impedance spectroscopy (EIS) of Nickel-Metal Hydride (NiMH) batteries is presented in this study. The resulting analytical expression is analogous to the impedance response of the Randles electrical circuit used for EIS analysis on NiMH batteries. The impedance model is validated against EIS measurements carried out whilst decreasing the state of charge (SOC) of a NiMH battery pack. The diffusion mechanisms during the discharge of the NiMH battery is modelled through a Warburg element derived from diffusion theory considering reflective boundary conditions. ZView® Scribner Associates Inc. software allowed the estimation of electrochemical and diffusion parameters from EIS measurements of the NiMH battery. The effect of diffusion mechanisms on EIS measurements is discussed. The results demonstrate that ion transport is the rate-limiting process during the discharge of the NiMH battery. This EIS-modelling study has provided an insight into the interpretation of battery electrochemical mechanisms represented in the Nyquist plot from EIS. It can assist to further EIS-modelling to study and correlate State of Health (SOH) in NiMH batteries for different applications.

Electrical and thermal conductivity models from Mamunya et al. and Kerner’s equation for elastic and flexural modulus have been applied to experimental data to assess model accuracies. Experimental data were gained from a previous study where polyethylene and carbon black, graphite and magnetite composites produced by injection and compression moulding were tested. The electrical conductivity modelling gave accurate fits to the data, though available data were limited and the thermal conductivity modelling produced good fits with R2 values greater than 0.93. The electrical and thermal model exponents were tuned for best fit and used to compare the modelling results with the literature and gain information about conduction mechanisms such as tunnelling and links, nodes and blobs and variations in local filler concentrations. A modified Kerner’s equation to effectively allow for filler type and variations in composite processing was used to improve upon the original equation which modelled modulus behaviour based on the pure matrix. The new equation proved to be a better predictor of elastic modulus than flexural modulus.

In this study, an analysis of the performance in a commercial open-cathode polymer electrolyte fuel cell (PEFC) stack is conducted using simultaneous electrochemical impedance spectroscopy (EIS) measurements. The factors that limit the performance of the PEFC stack were evaluated with EIS measurements and the impedance model developed in the authors’ previous study. The results showed that adsorbed intermediate species during the oxygen reduction reaction (ORR) limit the PEFC stack performance. The activation overpotential in the stack was dominated by low electrocatalytic activity from one of the cells. The inhomogeneity of air flow rate for this particular PEFC stack played an important role in oxygen transport limitations and ohmic resistance. This study has demonstrated that simultaneous EIS is a powerful tool for in-situ diagnosis of a PEFC stack. This EIS understanding has enabled an assessment of the state of health and performance of the fuel cell stack.

The elimination of corrosion, reduction of mass and the improvement of mechanical, electrical and thermal conductivity properties are the main aims to progress bipolar plate technology for polymer electrolyte membrane fuel cells. In addition, the large numbers of bipolar plates required in automotive fuel cell stacks (on the order of 400 plates per vehicle) will demand mass production to meet future demands as well as reduce costs through cheap production processes. Highly conductive, low density, low cost and corrosion-resistant materials that can be utilised in production processes such as injection and compression moulding are ideal candidates for bipolar plates. Carbon black, graphite, magnetite with polyethylene composites were made and tested for their electrical and thermal conductivities and mechanical properties and compared to the US Department of Energy targets for 2015. The carbon black composites exhibited better electrical conductivity than the other fillers where at 65 wt% the conductivity was ∼24 S/cm for through-plane conductivity and had a flexural strength of ∼32 MPa. Injection moulding produced composites with more material stability and greater mechanical strength than compression mouldings although compression mouldings produced composites with higher thermal conductivities where graphite displayed the highest thermal conductivity of ∼2 W/mK. Although well short of the US Department of Energy targets these materials show promise.

Bipolar plates are the interconnects between cells within a fuel cell stack. They must be highly electrically conductive in order to maximize the voltage across the stack and must be highly thermally conductive to aid cooling of the stack. Traditionally, bipolar plates are made from graphite or stainless steel; both have drawbacks such as low mechanical strength and corrosion problems, respectively. In order to overcome the problems associated with these common materials and to improve on the electrical and thermal conductivity aspects as well as decrease costs and improve manufacturability, a mixture of polyethylene and carbon was investigated. Composites of polyethylene and carbon were mixed using a two-roll mill and injection moulded. Micrographs of the polyethylene-carbon (PE-C) blends show how the microstructure of the polyethylene network and carbon particles provide increased mechanical properties but further addition of carbon leads to the degradation of these properties. Increasing carbon content led to an ever-increasing electrical conductivity. The material was tested for tensile and flexural properties, resulting in a maximum tensile and flexural strength of ∼24 MPa (at 26 wt% carbon in polyethylene) and ∼35 MPa (at 40 wt% carbon in polyethylene), respectively. The samples displayed electrical conductivity, with a maximum of 1.19 S/cm in-plane and 1.05 S/cm through-plane being achieved at a carbon loading of 65 wt%. The PE-C composite displayed low densities of 1.56 g/cm3 and desirable mechanical strength close to the US Department of Energy target level of 44.26 MPa for flexural strength. It was concluded that PE-C composites with different types of carbon and carbon fibres should be tested in order to reach the electrical conductivity target levels of 100 S/cm.

This article describes the processes undertaken to implement change in East Lancashire adult mental health services through New Ways of Working. The views of users, carers and staff of the services at the start of the project are described, and an overview offered of the development work that took place to support the change. Barriers to change are also described.

Models were developed to classify six different behaviours for a group of seven steers fitted with an accelerometer and pressure sensor. As part of the process, a greedy feature selection method was used to identify the most discriminatory inputs from a diverse set of statistical, spectral and information theory based features. The study showed the second order statistic features (standard deviation and sum of absolute values), which represent the level of motion intensity, were the most discriminatory individual features. The classification performance of models were further enhanced by using spectral features (with statistical features) to capture the periodicity of head movements and to differentiate between the dominant frequencies of various motions. Incorporating feature selection into model development not only improves model performance, but assists in understanding the different motion characteristics that enable behaviours to be discriminated.

We demonstrate an electrochemical method - which we term oxidative decoupling transfer (ODT) - for transferring chemical vapor deposited graphene from physically deposited copper catalyst layers. This copper oxidation-based transfer technique is generally applicable to copper surfaces, and is particularly suitable where the copper is adhered to a substrate such as oxidized silicon. Graphene devices produced via this technique demonstrate 30% higher mobility than similar devices produced by standard catalyst etching techniques. The transferred graphene films cover more than 94% of target substrates - up to 100 mm diameter films are demonstrated here - and exhibit a low Raman D:G peak ratio and a homogenous and continuous distribution of sheet conductance mapped by THz time-domain spectroscopy. By applying a fixed potential of -0.4 V vs. an Ag/AgCl reference electrode - significantly below the threshold for hydrogen production by electrolysis of water - we avoid the formation of hydrogen bubbles at the graphene-copper interface, preventing delamination of thin sputtered catalyst layers from their supporting substrates. We demonstrate the reuse of the same growth substrate for five growth and transfer cycles and prove that this number is limited by the evaporation of Cu during growth of graphene. This technique therefore enables the repeated use of the highest crystallinity and purity substrates without undue increase in cost. (C) 2015 Elsevier Ltd. All rights reserved.

Arginine vasopressin (AVP) is synthesised in magnocellular neurons (MCNs) of supraoptic nucleus (SON) and paraventricular nucleus (PVN) of the hypothalamus. In response to the hyperosmotic stressors of dehydration (complete fluid deprivation, DH) or salt loading (drinking 2% salt solution, SL), AVP synthesis increases in MCNs, which over-burdens the protein folding machinery in the endoplasmic reticulum (ER). ER stress and the unfolded protein response (UPR) are signaling pathways that improve ER function in response to the accumulation of misfold/unfold protein. We asked whether an ER stress response was activated in the SON and PVN of DH and SL rats. We observed increased mRNA expression for the immunoglobulin heavy chain binding protein (BiP), activating transcription factor 4 (Atf4), C/EBP-homologous protein (Chop), and cAMP responsive element binding protein 3 like 1 (Creb3l1) in both SON and PVN of DH and SL rats. Although we found no changes in the splicing pattern of X box-binding protein 1 (Xbp1), an increase in the level of the unspliced form of Xbp1 (Xbp1U) was observed in DH and SL rats. CREB3L1, a novel ER stress inducer, has been shown to be activated by ER stress to regulate the expression of target genes. We have previously shown that CREB3L1 is a transcriptional regulator of the AVP gene; however, a role for CREB3L1 in the response to ER stress has yet to be investigated in MCNs. Here, we used lentiviral vectors to introduce a dominant negative form of CREB3L1 (CREB3L1DN) in the rat SON. Expression of CREB3L1DN in the SON decreased Chop and Xbp1U mRNA levels, but not BiP and Atf4 transcript expression. CREB3L1 is thus implicated as a transcriptional mediator of the ER stress response in the osmotically stimulated SON.

The validity of electrochemical impedance measurements of polymer electrolyte fuel cells (PEFCs) have to be evaluated before an attempt is made to interpret the electrochemical mechanisms represented in the Nyquist plot. This evaluation can be carried out by data transformation of impedance measurements using Kramers-Kronig (K-K) relations. However, this evaluation has been commonly neglected in the fuel cell area due to the complexity of applying the mathematical K-K relations to real-world impedance measurements. In this study a computational algorithm, based on the Fast Fourier Transform (FFT) theory, the Hilbert transformation of impedance data, and a validated impedance model for PEFCs, for evaluating data transformation (real to imaginary Z’→Z’’ and imaginary to real Z’’→Z’) and hence validity of impedance measurements of PEFCs has been developed in Matlab®. With this computational algorithm it is possible to identify the factors that lead to incorrect EIS measurements of PEFCs such as inductance effect from the electrical cables of the measurement system, incorrect AC amplitude signal, and instability during EIS measurements. The computational algorithm developed in this study enables more accurate impedance results to be obtained to study the performance and state of health of PEFCs.

The authors explore the impact of growth in assets under management on the performance of small–cap investment managers. They find that small–cap manager excess returns have a statistically significant inverse relationship to both the level of assets under management and the annual growth in the amount. The relationship between assets and performance appears to be very consistent and to transcend different substyles within the universe of small–cap managers. The authors discuss the challenges these findings pose for current and prospective clients of small–cap managers.

Modern microbial mats are highly complex and dynamic ecosystems. Diffusive equilibration in thin films (DET) and diffusive gradients in thin films (DGT) samplers were deployed in a modern smooth microbial mat from Shark Bay in order to observe, for the first time, two-dimensional distributions of porewater solutes during day and night time. Two-dimensional sulfide and alkalinity distributions revealed a strong spatial heterogeneity and a minor contribution of sulfide to alkalinity. Phosphate distributions were also very heterogeneous, while iron(II) distributions were quite similar during day and night with a few hotspots of mobilization. Lipid biomarkers from the three successive layers of the mat were also analysed in order to characterize the microbial communities regulating analyte distributions. The major hydrocarbon products detected in all layers included n-alkanes and isoprenoids, whilst other important biomarkers included hopanoids. Phospholipid fatty acid profiles revealed a decrease in cyanobacterial markers with depth, whereas sulfate-reducing bacteria markers increased in abundance in accordance with rising sulfide concentrations with depth. Despite the general depth trends in community structure and physiochemical conditions within the mat, two-dimensional solute distributions showed considerable small-scale lateral variability, indicating that the distributions and activities of the microbial communities regulating these solute distributions were equally heterogeneous and complex.

We have successfully fabricated a pH-sensor array based on chemical-vapor-deposition (CVD)-synthesized graphene. As large-scale monolayer graphene is synthesized by this method, the size and the position of graphene can be controlled. Therefore, after transferring graphene onto SiO2/Si substrates, a graphene field-effect transistor (FET) array was produced. The sensing characteristics of the CVD-synthesized graphene-based device were investigated using three buffer solutions with different pH values (pHs 4.0, 6.8, and 9.3). The electrical measurements reveal that for most of the graphene FETs in the array, a similar stepwise increment in drain current was observed upon the introduction of each buffer solution with increasing pH value sequence. This will lead to the realization of the fabrication of multiplex hand-held chemical and biological sensors based on CVD-synthesized graphene.

Chemical vapor deposition on copper is the most widely used method to synthesize graphene at large scale. However, the clear understanding of the fundamental mechanisms that govern this synthesis is lacking. Using a vertical-flow, cold-wall reactor with short gas residence time we observe the early growths to study the kinetics of chemical vapor deposition of graphene on copper foils and demonstrate uniform synthesis at wafer scale. Our results indicate that the growth is limited by the catalytic dissociative dehydrogenation on the surface and copper sublimation hinders the graphene growth. We report an activation energy of 3.1 eV for ethylene-based graphene synthesis.