bluuebunny/crossref_metadata_2025 huggingface dataset:
Flow Uniformity of Catalytic Burner for Off-Gas Combustion of Molten Carbonate Fuel Cell
Authors: Lee Sangmin , Ahn Kook Young , Lee Young Duk , Han Jaeyoung , Im Seokyeon , Yu Sangseok
Published: March 2012

A catalytic combustor is a device to burn off fuel by surface combustion that is used for the combustion of anode off-gas of molten carbonate fuel cells by employing the catalytic combustor. Purified exhaust gas can be recirculated into the cathode channel for CO2 supply to improve thermal efficiency. The design of a catalytic combustor depends on many parameters, but flow uniformity is particularly important during the emergency shut-down of a fuel cell stack. Before the temperature control of a catalytic combustor is activated, the catalytic combustor should burn off more than two times the rated amount of the fuel flow rate. Under overload conditions, assurance of flow uniformity at the inlet of the catalytic combustor can reduce damage to the catalytic burner that can be caused by a local hot zone. In this study, flow uniformity of the catalytic combustor was investigated in two steps: a preliminary step with a model combustor and a main analysis step with a practical 250 kW catalytic combustor. Models of the 0.5 and 5 kW class combustors were used in the preliminary step. In the preliminary step the model combustors were used to determine supporting matters for flow uniformity. The inlet direction of the mixing chamber below the catalytic combustor was also examined in the preliminary step. In the main analysis step the flow uniformity of the scale-up combustor was examined with selected supporting matter and inlet direction into the mixing chamber. Geometric and operating parameters were investigated. In particular, the flow rate under off-design operating conditions was examined.
Pore Structure Modeling of Flow in Gas Diffusion Layers of Proton Exchange Membrane Fuel Cells
Authors: Shi Z. , Wang X.
Published: March 2012

The gas diffusion layer (GDL) in a proton exchange membrane (PEM) fuel cell has a porous structure with anisotropic and non-homogenous properties. The objective of this research is to develop a PEM fuel cell model where transport phenomena in the GDL are simulated based on GDL’s pore structure. The GDL pore structure was obtained by using a scanning electron microscope (SEM). GDL’s cross-section view instead of surface view was scanned under the SEM. The SEM image was then processed using an image processing tool to obtain a two-dimensional computational domain. This pore structure model was then coupled with an electrochemical model to predict the overall fuel cell performance. The transport phenomena in the GDL were simulated by solving the Navier-Stokes equation directly in the GDL pore structure. By comparing with the testing data, the fuel cell model predicted a reasonable fuel cell polarization curve. The pore structure model was further used to calculate the GDL permeability. The numerically predicted permeability was close to the value published in the literature. A future application of the current pore structure model is to predict GDL thermal and electric related properties.
The Numerical Study of Geometric Influence of Flow Channel Patterns on Performance of Proton Exchange Membrane Fuel Cells
Authors: Chen Chiun-Hsun , Chen Chang-Hsin , Chen Tang-Yuan
Published: March 2012

This study numerically investigates how the geometry of flow pattern influences performance of proton exchange membrane fuel cell (PEMFC), and analyzes how these parameters lead to different distributions of model variables. The investigation focuses on the impact of different bend angle and width of serpentine flow channels and tests how they improve the performance. Three-dimensional simulations are carried out with a steady, two-phase, multicomponent and electrochemical model, using CFD-ACE+, the commercial CFD code. Through simulation with various bend angles and widths, the results show that the combination of 60 deg and 120 deg for flow pattern achieves the highest performance at low operating voltage regime, and flow pattern with wider bend width also produces more current at low operating voltages. Plots of current density indicate that high current density locates at the bending areas of the channels. Therefore, the output current densities of each pattern are improved from the change of bend angle and width.
State of the Art of Experimental Studies and Predictive Methods for Slug Liquid Holdup
Authors: Pereyra Eduardo , Arismendi Rosnayi , Gomez Luis E. , Mohan Ram S. , Shoham Ovadia , Kouba Gene E.
Published: March 2012

A summary of all available correlations and mechanistic models for the prediction of slug liquid holdup is presented. Additionally, an experimental data base for slug liquid holdup has been collected from available literature. A comparison between the predictions of available models and correlations against the data base is presented, identifying the range of applicability of the different methods. The correlations have been tuned against the new data by calculating new values of their constant parameters, showing an improved performance. Also, the uncertainties of the correlations parameters are evaluated and presented. A recommendation for the best method of predicting the slug liquid holdup is provided.
Secondary Instabilities in Incompressible Axisymmetric Boundary Layers: Effect of Transverse Curvature
Authors: Vinod N. , Govindarajan Rama
Published: March 2012

The secondary instability of the incompressible boundary layer in the axial flow past a cylinder is studied. The laminar flow is shown to be always stable at high transverse curvatures to secondary disturbances. Because the primary mode is stable as well, (Tutty et al., 2002, “Boundary Layer Flow on a Long Thin Cylinder,”. Phys. Fluids, 14(2), pp. 628–637), this implies that the boundary layer on a thin long cylinder may undergo transition to turbulence by means very different from that on a flat plate. The azimuthal wavenumber of the least stable secondary modes (m±) are related to that of the primary (n) by m+ = 2n and m− = −n. The base flow is shown to be inviscidly stable at any curvature.
Computational Fluid Dynamics Analysis of a Hydrokinetic Turbine Based on Oscillating Hydrofoils
Authors: Kinsey Thomas , Dumas Guy
Published: March 2012

The performance of a new concept of hydrokinetic turbine using oscillating hydrofoils to extract energy from water currents (tidal or gravitational) is investigated using URANS numerical simulations. The numerical predictions are compared with experimental data from a 2 kW prototype, composed of two rectangular oscillating hydrofoils of aspect ratio 7 in a tandem spatial configuration. 3D computational fluid dynamics (CFD) predictions are found to compare favorably with experimental data especially for the case of a single-hydrofoil turbine. The validity of approximating the actual arc-circle trajectory of each hydrofoil by an idealized vertical plunging motion is also addressed by numerical simulations. Furthermore, a sensitivity study of the turbine’s performance in relation to fluctuating operating conditions is performed by feeding the simulations with the actual time-varying experimentally recorded conditions. It is found that cycle-averaged values, as the power-extraction efficiency, are little sensitive to perturbations in the foil kinematics and upstream velocity.
Effects of Corner/Edge Bonding and Underfill Properties on the Thermal Cycling Performance of Lead Free Ball Grid Array Assemblies
Authors: Borgesen P. , Blass D. , Meilunas M.
Published: March 2012

Underfilling will almost certainly improve the performance of an area array assembly in drop, vibration, etc. However, depending on the selection of materials, the thermal fatigue life may easily end up worse than without an underfill. This is even more true for lead free than for eutectic SnPb soldered assemblies. If reworkability is required, the bonding of the corners or a larger part of the component edges to the printed circuit board (PCB), without making contact with the solder joints, may offer a more attractive materials selection. A 30 mm flip chip ball grid array (FCBGA) component with SAC305 solder balls was attached to a PCB and tested in thermal cycling with underfills and corner/edge bonding reinforcements. Two corner bond materials and six reworkable and nonreworkable underfills with a variety of mechanical properties were considered. All of the present underfills reduced the thermal cycling performance, while edge bonding improved it by up to 50%. One set of the FCBGAs was assembled with a SnPb paste and underfilled with a soft reworkable underfill. Surprisingly, this improved the thermal cycling performance slightly beyond that of the nonunderfilled assemblies, providing up to three times better life than for those assembled with a SAC305 paste.
An Experimental and Computational Study on Moisture Induced Epoxy Swelling in Non-hermetic Optoelectronic Packages
Authors: Madduri Sushma , Infantolino William , Sammakia Bahgat.G
Published: March 2012

Moisture induced epoxy swelling is a potential failure mechanism in nonhermetic packages. Epoxy materials used in the package absorb moisture and swell in a relatively humid environment. This will result in hygroscopic stresses in the material that can eventually lead to failure. The coefficient of hygroscopic swelling (CHS) is a material property that characterizes moisture induced swelling in the material. It is defined as the ratio of hygroscopic strain to the moisture concentration in the material. Prior research investigated the measurement of CHS experimentally using techniques such as thermo mechanical analysis (TMA) (Ardebili et al., 2003, “Hygroscopic Swelling and Sorption Characteristics of Epoxy Molding Compounds Used in Electronic Packaging,” IEEE Trans. Compon. Packag. Technol., 26(1), pp. 206–214; Mckague et al., 1978, “Swelling and Glass Transition Relations for epoxy Matrix Material in Humid Environments,” J. Appl. Polym. Sci., 22, pp. 1643–1654.), Moiré interferometry (Han et al., 2003, “Measurement of the Hygroscopic Swelling Coefficient in Mold Compounds Using Moire Interferometer Experimental Techniques,” IEEE Trans. Compon. Packag. Technol., 27(4), pp. 40–44), and digital image correlation (DIC) (Park and Zhang, 2007, “Investigation of Hygroscopic swelling of Polymers in Freezing Temperature,” ASME International Mechanical Engineering Congress and Exposition). Some of these studies recommended investigation of improved measurement techniques, while others made some procedural assumptions that may not be applicable for all materials. One of the goals of this study was to investigate an improved technique for CHS measurement and helps to better understand the various factors that affect the measurement. The DIC technique was used to measure the moisture swelling of the epoxy material considered for use in the package. Moisture loss during the measurement results in a change in moisture concentration in the sample. While it may be thought that the moisture loss during the DIC scan can be assumed negligible due to the short test time compared with other methods, this assumption did not hold well for the current epoxy material. The ramp rate chosen for the test affects the moisture loss. It introduces a level of nonuniformity in temperature and moisture distribution in the sample. A suitable value that takes into account both of these effects was determined. The moisture loss measured during the DIC scan was accounted for in the CHS computation. In addition to this, the temperature and concentration dependence of the CHS was determined. Results indicated that the temperature and concentration effects are small for the current test material within the test temperature range. The moisture loss found during the DIC measurement leads to a nonuniform moisture distribution in the sample. This was characterized by using experimental and computational methods and the effect on the measurement was determined.
Performance of Axial Fans in Close Proximity to the Electromagnetic Compatibility Screens
Authors: Antón R. , Bengoechea A. , Rivas A. , Ramos J. C. , Larraona G. S.
Published: March 2012

The performance of axial fans in close proximity to the electromagnetic compatibility (EMC) screens was analyzed by means of an experimental parametric study. The following geometrical parameters were studied: the hub-to-tip ratio, the ratio between fan thickness and fan diameter, the porosity and thickness of the perforated plate, and finally, the distance between the perforated plate and the inlet and the outlet of the fan. Screen porosity was found to be the most important parameter. Fan performance degradation is expressed by means of two correlations: one for the deterioration in the fan pressure at the no-flow point and the other for the flow rate reduction at the free delivery point. Both correlations were formulated as functions of screen porosity and the distance between the fan and the screen. We believe that the correlations can serve as a good guide for correct fan placement in a telecommunications cabinet.
Influence of Gap Height in Flip Chip Underfill Process With Non-Newtonian Flow Between Two Parallel Plates
Authors: Khor C. Y. , Abdullah M. Z. , Abdul Mujeebu M.
Published: March 2012

In this paper, the finite volume method (FVM) is used for the simulation of flip chip underfill process by considering non-Newtonian flow between two parallel plates that emulate the silicon die and the substrate. 3D model of two parallel plates of size 12.75 mm × 9.5 mm with gap heights of 5 μm, 15 μm, 25 μm, 35 μm, 45 μm, and 85 μm are developed and simulated by computational fluid dynamic (CFD) code, fluent 6.3.26. The flow is modeled by using power law model and volume of fluid (VOF) technique is applied for flow front tracking. The effect of change in height of the gap between the plates on the underfill process is mainly studied in the present work. It is observed that the gap height has significant influence on the melt filling time and pressure drop, as the gap height decreases filling time and pressure drop increase. The simulation results are compared with previous experimental results and found in good conformity.
A New Approach to Analytical Solution of Cantilever Beam Vibration With Nonlinear Boundary Condition
Authors: Sedighi Hamid M. , Shirazi Kourosh H.
Published: March 2012

This paper presents the application of novel and reliable exact equivalent function (EF) for deadzone nonlinearity in an analytical investigation of nonlinear differential equations. A highly nonlinear equation of cantilever beam vibration with a deadzone nonlinear boundary condition is used to indicate the effectiveness of this EF. To obtain the analytical solution of dynamic behavior of the mentioned system, a powerful method, called He’s parameter expanding method (HPEM) is used. Comparison of the obtained solutions using a numerical method reveals the accuracy of this analytical EF.
Dynamic Response of Multibody Systems with Multiple Clearance Joints
Authors: Flores Paulo , Lankarani Hamid M.
Published: March 2012

A general methodology for the dynamic modeling and analysis of planar multibody systems with multiple clearance joints is presented. The inter-connecting bodies that constitute a real physical mechanical joint are modeled as colliding components, whose dynamic behavior is influenced by the geometric, physical and mechanical properties of the contacting surfaces. A continuous contact force model, based on the elastic Hertz theory, together with a dissipative term associated with the internal damping, is utilized to evaluate the intra-joint normal contact forces. The incorporation of the friction phenomenon, based on the classical Coulomb’s friction law, is also included in this study. The suitable contact force models are embedded into the dynamic equations of motion for the multibody systems. In the sequel of this process, the fundamental methods to deal with contact-impact events in mechanical systems are presented. Finally, two planar mechanisms with multiple revolute clearance joints are used to demonstrate the accuracy and efficiency of the presented approach and to discuss the main assumptions and procedures adopted. The effects of single versus multiple clearance revolute joints are discussed.
Implementation of a Mixing Length Turbulence Formulation Into the Dynamic Wake Meandering Model
Authors: Keck Rolf-Erik , Veldkamp Dick , Madsen Helge Aagaard , Larsen Gunner
Published: March 2012

The work presented in this paper focuses on improving the description of wake evolution due to turbulent mixing in the dynamic wake meandering (DWM) model. From wake investigations performed with high-fidelity actuator line simulations carried out in ELLIPSYS3D, it is seen that the current DWM description, where the eddy viscosity is assumed to be constant in each cross-section of the wake, is insufficient. Instead, a two-dimensional eddy viscosity formulation is proposed to model the shear layer generated turbulence in the wake, based on the classical mixing length model. The performance of the modified DWM model is verified by comparing the mean wake velocity distribution with a set of ELLIPSYS3D actuator line calculations. The standard error (defined as the standard deviation of the difference between the mean velocity field of the DWM and the actuator line model), in the wake region extending from 3 to 12 diameters behind the rotor, is reduced by 27% by using the new eddy viscosity formulation.
Thermal Performance Prediction of a Biomass Based Integrated Gasification Combined Cycle Plant
Authors: Srinivas T. , Reddy B. V. , Gupta A. V. S. S. K. S.
Published: March 2012

The performance characteristics of a rice husk based integrated gasification combined cycle (IGCC) plant has been developed at the variable operating conditions of gasifier. A thermo-chemical model developed by the authors has been applied for wet fuel (fuel with moisture) for predicting the gas composition, gas generation per kg of fuel, plant efficiency and power generation capacity, and NOx and CO2 emissions. The effect of the relative air fuel ratio (RAFR), steam fuel ratio (SFR), and gasifier pressure has been examined on the plant electrical efficiency, power output, and NOx and CO2 emissions of the plant with and without supplementary firing (SF) between gas turbine (GT) outlet and heat recovery steam generator (HRSG). The optimum working conditions for efficient running of the IGCC plant are 0.25 RAFR, 0.5 SFR, and 11 bar gasifier pressure at the GT inlet temperature of 1200 °C. The optimum operational conditions of the gasifier for maximum efficiency condition are different compared to maximum power condition. The current IGCC plant results 264.5 MW of electric power with the compressor air flow rate of 375 kg/s at the existed conventional combined cycle plant conditions (Srinivas et al., 2011, “Parametric Simulation of Combined Cycle Power Plant: A Case Study,” Int. J. Thermodyn. 14(1), pp. 29–36). The optimum compressor pressure ratio increases with increase in GT inlet temperature and decreases with addition of SF.
Low Pressure Turbine Relaminarization Bubble Characterization using Massively-Parallel Large Eddy Simulations
Authors: Jagannathan Shriram , Schwänen Markus , Duggleby Andrew
Published: March 2012

The separation and reattachment of suction surface boundary layer in a low pressure turbine is characterized using large-eddy simulation at Ress = 69000 based on inlet velocity and suction surface length. Favorable comparisons are drawn with experiments using a high pass filtered Smagorinsky model for sub-grid scales. The onset of time mean separation is at s/so = 0.61 and reattachment at s/so = 0.81, extending over 20% of the suction surface. The boundary layer is convectively unstable with a maximum reverse flow velocity of about 13% of freestream. The breakdown to turbulence occurs over a very short distance of suction surface and is followed by reattachment. Turbulence near the bubble is further characterized using anisotropy invariant mapping and time orthogonal decomposition diagnostics. Particularly the vortex shedding and shear layer flapping phenomena are addressed. On the suction side, dominant hairpin structures near the transitional and turbulent flow regime are observed. The hairpin vortices are carried by the freestream even downstream of the trailing edge of the blade with a possibility of reaching the next stage. Longitudinal streaks that evolve from the breakdown of hairpin vortices formed near the leading edge are observed on the pressure surface.
Simulation Based Design of Disk Resonator Biosensors Under Fabrication Uncertainty
Authors: Heidari Amir , Yoon Yong-Jin , Son Hungsun , Choi Hae-Jin
Published: March 2012

A high performance and cost effective biosensor is designed using a radial contour-mode disk resonator (RCDR). This sensor measures tiny biological mass attached on a disk vibrating at a high frequency, producing high quality of output signal. A series of analysis and simulation models is developed to predict the mass sensitivity, dynamic stability, and motional resistance of the RCDR biosensor with given geometry and signal input. In order to decrease motional resistance while keeping the fabrication cost low, a layer of dielectric material is deposited within the capacitor gap. In designing the RCDR biosensors, we employ Type I, II, and III robust design approach to design a device that is insensitive to various types of uncertainty associated with the fabrication processes and analysis models. A mathematical construct, error margin index, is employed for this robust design. Traditional optimization and robust design approaches are separately formulated, solved, and compared. From the design results, we observe that the RCDR is a promising bio-sensing device compared to the existing ones.
Perceptual Attributes in Product Design: Fuel Economy and Silhouette-Based Perceived Environmental Friendliness Tradeoffs in Automotive Vehicle Design
Authors: Reid Tahira N. , Frischknecht Bart D. , Papalambros Panos Y.
Published: March 2012

The quest for improved fuel efficiency and environmental friendliness is transforming automotive vehicle design. In addition to new energy sources and management, new powertrain technologies offer increased flexibility in the spatial arrangement (packaging) and exterior shape (styling) of a vehicle. Design choices in packaging and styling are closely linked to consumer preferences, particularly those that influence consumers’ decisions about the objective qualities of a product (i.e., perceptual attributes). The ability to include perceptual attributes into a design optimization study is a valuable extension of the more traditional engineering approach that looks at only functional attributes. Previous work has studied the quantification of perceived environmental friendliness (PEF) in vehicle silhouette design. In this paper, empirically validated PEF silhouette attributes are included as constraints in a vehicle optimization model that maximizes fuel economy. Results indicate that there is a tradeoff between PEF preferences and the attainable fuel economy for a given vehicle, where increasing vehicle length leads to increasing PEF and decreasing fuel economy.
New Concepts on Two-Dimensional Data Visualization With Applications in Engineering Analysis and Design
Authors: Simionescu P. A. , Mehrubeoglu Mehrube
Published: March 2012

The use of information visualization in engineering analysis and design has increased exponentially, making it indispensable in science and engineering education. In this paper, several new concepts on graphical representation of two-dimensional data are presented, and their implementation in a computer program called D_2D detailed. Application examples include mechanism kinematics, vibrations, and optimizations. New ideas on plotting inequalities of two variables, damping ratio evaluation of single degree-of-freedom vibratory systems, and time ratio calculation of crank-driven mechanisms are presented in paper.
High intensity focused ultrasound with large aperture transducers: A MRI based focal point correction for tissue heterogeneity
Authors: Mougenot Charles , Tillander Matti , Koskela Julius , Köhler Max O. , Moonen Chrit , Ries Mario
Published: March 2012

Purpose:

The risk of undesired tissue damage to thoracic cage, heart, and lung during MR guided HIFU ablations of breast cancer can be greatly reduced if a phased array transducer design with a lateral beam direction is used in combination with a large aperture. The disadvantage is an increased sensitivity to focus aberrations due to tissue heterogeneity. Here, the authors propose to restore the focal coherence by using a matched aperture phase correction, which is based on a noninvasively obtained tissue model.

Methods:

The method combines high resolution MRI with ultrasound wave measurements of different tissue types to determine a phase correction, which compensates focal point aberrations caused by tissue heterogeneity. 3D segmentation of tissue is used to quantify the relative proportion of each tissue type along a line running from the center of each element of the phased array to the target focal point.

Results:

For tissue types with a celerity difference of 3%, the proposed method allows to quantify the phase aberration with an accuracy of 6° ± 20° and a correlation factor R² = 0.95. Using the refocusing method for a complex heterogeneous phantom resulted in 95% of the maximal pressure, whereas only 70% of the maximal pressure is obtained in absence of any phase correction.

Conclusions:

Since the proposed refocusing algorithm is compatible with a standard interventional preplanning and requires only a minimal amount of processing, it presents a promising approach to compensate for aberration in heterogeneous tissues such as the human breast.
Interactive Heat Transfer Simulations for Everyone
Authors: Xie Charles
Published: March 2012

Heat transfer is widely taught in secondary Earth science and physics. Researchers have identified many misconceptions related to heat and temperature.1These misconceptions primarily stem from hunches developed in everyday life (though the confusions in terminology often worsen them). Interactive computer simulations that visualize thermal energy, temperature distribution, and heat transfer may provide a straightforward method for teaching and learning these concepts. Through interacting with visual representations of the concepts and observing how they respond to manipulations, the misconceptions may be dispelled more effectively. This paper presents a new educational simulation tool called Energy2D developed to explore this idea.
Asking the right questions
Authors: Badraslioglu Duruhan
Published: March 2012

My school's science department recently had a meeting with the English department. It is an unusual (at least in my experience) occurrence for these two departments to meet since at first glance there seems to be little about which they might collaborate. However, after years of discussing a persistent, troubling problem casually within the science department, it dawned on us that our problem was not a scientific problem but a language problem. The issue that was getting our attention was this: There is an apparent discrepancy between what the teacher is asking and what the student thinks the teacher is asking. Let me elaborate with some examples below.
PB1 A new measure to assess the quality of care at the emergency department from patients' perspective in The Netherlands
Authors: Bos N , Sturms L M , Schrijvers A , van Stel H
Published: March 2012

Objectives and Background

Measurements of patients' perceptions have been recognised as an important part of evaluations of the quality of care. However, in the Netherlands a standardised and validated instrument to systematically measure how patients experience the healthcare delivered in an emergency department (ED) is lacking. Therefore, we developed the Consumer Quality Index for the Emergency Department (CQI ED).

Methods

The CQI ED was developed according to the national CQI guideline. First, qualitative research was used to construct the CQI ED. Second, to assess psychometric characteristics the 84-item CQI ED, temporarily extended with 50 important questions, was sent to 653 patients who attended a large-sized ED in the Netherlands in January 2010. Exploratory factor analyses were used to determine the domains of the questionnaire. Improvement scores were computed by multiplying the importance scores with the percentages to the negative answering categories of the experience questions.

Results

Survey data of 304 (47%) patients were used for analyses. The first exploratory factor analysis resulted in 15 items grouped in three internally consistent domains: Attitude of the healthcare professionals, environment and impression of the ED and respect and explanation towards the patient. The second analysis, ignoring the general CQI guidelines, included 27 items and resulted in 5 domains: Attitude of the healthcare professionals, information and explanation, environment of the ED, leaving the ED, and general information and rapidity of care. The three most important aspects in healthcare performance at the ED were: trust in the competence of the healthcare professionals, hygiene at the ED and received care as expected. The highest improvement scores were mostly about informing patients.

Conclusions

The CQI ED is a reliable instrument to measure patients' experiences with care at the ED and seems applicable for local quality improvement. Preferring a construct of three or five domains depends on the choice for a between-ED or within-ED comparison.
PB10 Safe Elderly Emergency Discharge (SEED) project: determining best practice for safe discharge of the older emergency patient
Authors: Lowthian J , Cameron P , Smit D , Newnham H , Hunter P , Brand C , Barker A , Banerjee J , Cooke M
Published: March 2012

Background and Objectives

Increasing numbers of older patients presenting for emergency hospital care is a major worldwide concern. The fastest growth is in people aged ≥65 years representing 18% of all presentations. An ED visit for older people is a sentinel health event that can lead to substantial functional decline and adverse outcomes. This age group present with more complex conditions, consume more resources, have longer ED stays, are more likely to be admitted, have long hospital stays, and a higher rate of re-presentation. This will increase with population ageing. Although social/psychological support is often required there is little evidence this occurs in a systematic coordinated manner.

SEEDaims to

Determine whether current models of emergency care ensure safe discharge and facilitate optimal health outcomes for older patients.

Develop a tailored evidence-based care framework applicable to Australian and international settings.

Methods

PHASE 1: Review of best practice: Systematic review of best evidence for models of care for older patients in ED or short stay units.

PHASE 2: Evaluation of methods for assessment of unsafe discharge risk: Evaluation of effectiveness of discharge risk screening tools designed to reduce risk of unsafe discharge.

PHASE 3: Audit current practice against published best practice: Prospective process mapping of the patient care journey in 3 EDs in Australia and UK: during ED stay and post-discharge, with monitoring of health outcomes in the following 6 months.

Expected Outcomes

Development of an Older Patient Care Service Framework: Redesign of emergency care for older patients. To include:

Development of policy and principles of management, care pathways, and performance improvement measures.

Validation of an unsafe discharge screening tool in an Australian & English cohort.

Development of a stream-lined care pathway.

Reduced ED length of stay.

Improved patient experience.

Safe discharge with optimisation of health outcomes, reduced unplanned emergency re-presentations; reduced need for higher level residential care; reduced unplanned deaths.

Reduced emergency demand and improved patient flow.
PB12 Documentation of intravenous morphine administration in the emergency department
Authors: MacDougall-Davis Sophie
Published: March 2012

Objectives and Background

Intravenous morphine is commonly used in the Emergency Department (ED) and is often prescribed with a dose range from 1 to 10 mg to allow for administration to be titrated to pain. Accurate documentation of the actual dose given or multiple doses given under a single prescription is a legal requirement and is particularly important for a controlled drug. Inadequate documentation may lead to over- or under-dosing, poor handover from ED staff to wards/theatres and raises issues of patient safety, clinical effectiveness and potential medico-legal consequences. We aimed to assess documentation of morphine administration within the ED and evaluate methods for improving practice.

Methods

Documentation of morphine prescribing was reviewed against pharmacy guidelines for a baseline sample of 1200 attendances to our department over a 1-month period. Following staff re-education and protocol dissemination the review was repeated prospectively. After the second review a prescribing sticker was introduced, prompting documentation of the number, dose and timing of morphine boluses given to satisfy each variable dose prescription. A third prospective review was performed.

Results

Overall, 3600 ED attendances were investigated over the three reviews. In 172 cases the drug chart included a variable dose prescription of intravenous morphine. The baseline review showed the actual dose of morphine administered was documented in only 66% of cases. Following re-education and protocol dissemination adherence to pharmacy guidelines rose to 89% and after the introduction of prescribing stickers this increased further to 98%.

Conclusions

The use of a simple drug chart modification and re-education has been shown to improve the documentation of morphine administration to a near perfect level within the ED. Accurate prescribing of controlled drugs is essential and methods such as this can be easily employed to improve patient safety and quality of care.
PB14 Audit of procedural sedation in the Emergency Department of Wishaw General Hospital
Authors: Millington R
Published: March 2012

Objectives and Background

Sedation is a commonly performed procedure with a number of significant consequences should it go wrong. The Working Party chaired by Royal College of Anaesthetists, Canadian Consensus Guidelines and the American College of Emergency Physicians have all published guidelines detailing the minimum standards required for safe sedation. These cover the topics of patient assessment, general facilities, sedation procedure and post-sedation care. Our aims were twofold: to determine if sedation was being carried out safely and whether documentation was thorough.

Methods

Thirty eight notes from August 2010 to February 2011 were retrospectively reviewed. These were identified by searching the department database for diagnoses of “dislocation” and “radial fracture”, then cross-referencing with patients who received midazolam (recorded in the controlled drugs register). Children were excluded. The data collected was compared against aforementioned published guidelines.

Results

There was no recorded assistant in 25/38 (66%) of cases. Drug doses were not recorded in 14/38 (37%) and in 7/38 (18%) there was no prescription. Physiological monitoring was documented in only 11/38 (29%) of cases. Fasting status was recorded in 6/38 (16%) of cases. Of patients discharged home 24/38 (63%), there was no documentation of follow-up in 15/24 (62.5%). The notes were recorded by the following staff: junior 19/38 (50%), middle grade 11/38 (29%), Consultant 5/38 (13%) and other 3/38 (8%).

Conclusions

Documentation is falling short of achieving the expected standards. Essential aspects of safe sedation are not being carried out. All ED doctors now have to attend a short workshop on safe sedation prior to carrying out any procedures requiring sedation. A sedation form is being introduced for recording and monitoring purposes. We have organised a re-audit starting in September to see if our changes have improved practice.
PB15 Retrospective re-audit of the 48 h post-admission mortality rates via an emergency department (ED) in the UK
Authors: Ritchie R , Wilson J , Tolat V
Published: March 2012

Objectives and Background

The Medway Maritime District General Hospital's Emergency Department (ED) had a patient census of 84 000 in 2009. Monthly adverse events in 2008 and 2009 prompted a 48-h post admission mortality audit in July 2009 which identified multiple hospital and departmental failings with some related to a chain of missed events. Changes to clinical and operational practices within the department were implemented. These include: reducing Inappropriate Observation Ward admissions, the greater use of the Medway Modified Early Warning System scores, early Clinical Intervention by senior ED doctors and on-call teams, reducing the length of stay of critical care patients, improving Written and Chart Documentations, and changes to Staffing Rota & Skill-mix. The impact of these changes was re-audited in 2010.

Method

The demographic and clinical / nursing records of patients who died within 48-h of admission and were seen by an ED doctor were analysed for July 2009 and January 2010. Patients seen by other admitting specialities were excluded.

Result

7326 and 6664 patients registered in July 2009 and January 2010 respectively. The majority of patient deaths occurred in the medical and surgical units. Both audited groups had similar age, age range, and sex distribution, and mortality demographics (14 and 13 deaths respectively).The emergency department had no recorded deaths in January 2010 and continued to record zero mortality for several months in 2010.

Conclusions

The 48-h mortality audit could be an effective quality evaluation tool for EDs. Changes to operational practices and attitudes towards patient care and mortality reduction require a systematic programme of changes across an organisation and are not solely the responsibility of any one department.
PB17 Handover tool use in the emergency department
Authors: Shere H
Published: March 2012

Objectives and Background

Ongoing patient management in the Emergency Department involves the handing over of patients between medical and nursing staff. Ideally, this should enable the receiving staff to be as well informed as their predecessors to ensure optimal patient care. In practice this has been found to be one of the most dangerous aspects of shift working patterns. Handovers are highly variable and often perceived to be diverting attention from seeing patients, rather than an essential part of their care.

Methods

I have designed a more formal written handover tool to enable a one-to-one written, sit-down handover. The aim of this is to ensure that routine investigations carried out are appropriately checked and that the new doctor knows exactly what is left to chase up. The idea is that both doctors sign the bottom of the handover sheet and this is used as part of the notes to show it took place.

Results

I have been successfully trialling this in Poole Hospital Emergency Departmen, Dorset.

Conclusions

I feel that robust handover systems such as this need to be instigated more rigorously in order to prevent latent errors that may occur due to lack of continuity of care.
PB18 Minor injury units: are they a safe alternative for emergency treatment of orthopaedic minor injuries?
Authors: Smith J , Balogun-Ojuri B , Chesser T
Published: March 2012

Objectives and Background

With the drive to bring the provision of emergency care into the community, the number of minor injury units (MIU) is rising. While these units may lead to improved access to medical services, they must be introduced without compromise to quality of patient care. This study aims to determine whether the quality of care delivered by two MIU in the community is akin to that provided by a hospital Emergency Department (ED), and thus a safe and efficient use of NHS time and resources.

Method

Retrospective case note review of orthopaedic outpatient fracture clinic referrals from two MIU (one fully established and one recently opened) and one teaching hospital ED. Units were assessed on their accuracy of diagnosis and initial management.

Results

A total of 439 orthopaedic outpatient referrals were included from July–September 2010. Appropriate management was achieved in 63% of referrals from the newly opened MIU, compared with 81% from the teaching hospital ED (p=0.003). 64% of the newly opened MIU patients were correctly diagnosed, versus 83% at the ED (p=0.001). A quarter of patients who attended the recently opened MIU received inappropriate initial treatment (p=0.04). There was no significant difference between results for the established MIU and the ED in any measure.

Conclusion

For the management of minor orthopaedic injury, well supported nurse-led centres can provide a safe and effective alternative to doctor led care, thus reducing the workload on already burdened hospital EDs. However, new nurse-led MIU must have close observation and tight regulation to prevent the inefficient use of NHS resources and more importantly a risk to patient safety and quality of care.
PB2 Improving handovers in the emergency department
Authors: Delport M
Published: March 2012

Objectives and Background

Transitions in patient care pose a significant risk to patient safety, because they can lead to discontinuity of patient care and adverse events due to information loss during handover or unnecessary delays as a result of poor handover.

The goals of our project were to:

Create a standardised process and documentation for doctor-to-doctor handover in our Emergency Department (ED).

Improve handover as an educational experience for registrars.

Shorten the duration of handover without compromising quality of information.

Methods

Setting: Urban district ED with 40 000 presentations annually.Development of best practice handover process:Handover processes were audited using video and direct observation by the Handover Improvement Team. Data collected included times, information quality and documentation. Staff and patient surveys were undertaken. Best practice was defined by literature review, multidisciplinary collaboration and consumer input. Handover process and forms were compiled into a new handover policy.Implementation:The new policy was presented at educational meetings, circulated to staff via email and advertised by poster in the ED and handover room.Re-audit:Handover audit by Handover Improvement Team was repeated. Patient handover forms were reviewed. Staff survey was undertaken.Analysis:Descriptive statistics were used to analyse data.

Results

The development phase took 7 months and resulted in our “SHARE the CARE Plan”, which will be presented. Implementation occurred over 3 weeks. Post-implementation audit showed improvement in documentation, increased multidisciplinary collaboration and teaching. A staff survey showed that the majority of doctors surveyed agreed that the new process was appropriate and helpful. Other results will be presented.

Conclusions

Development of a new best practice policy with a multidisciplinary team takes time. The new handover process is supported by the majority of staff and has resulted in improved documentation, collaboration and teaching.
PB3 Head injury: a system of rapid referral
Authors: Geddes L , Wright K , Clarke S
Published: March 2012

Objectives and Background

To develop a streamlined referral pathway for isolated head injuries in Trauma Units. Severe head injury (ISS >15) is a major problem in the UK. For 2010, TARN data shows 21 192 submissions, of these 7521 had an ISS >15 and 5086 were AIS 3+ in the head. Current recommendations are that all patients' GCS <9 are taken to a Major Trauma Centre giving rapid access to Neurosurgery and improving outcome. The development of integrated trauma systems is addressing this but despite the presence of primary bypass in the pre-hospital arena, under-triaged patients arrive in Trauma Units. These need rapid referral by secondary “hot” transfer protocols. The system works well for patients with polytrauma; however isolated head injuries are still not being transferred rapidly.

Methods

Six months of data in the TARN report (February 2011) was reviewed for all patients ISS >15. Outcome at 3 and 30 days, discussions with Neurosurgeons, and subsequent transfers were determined. Time to CT was compared for all ISS >15, those meeting NICE head injury guidelines, and isolated head injury patients.

Results

60% of ISS >15 patients were isolated head injuries. 29% died within 30 days, 26% within 3 days. 74% of all patients were discussed with the neurosurgeons (82% of isolated head injuries) and 13% transferred. Median time to CT was 2.2 h (IQR 1.2–12.1) for all, 2.2 h (1.2–5.95) if meeting NICE guidelines and 1.8 h (1.1–7.5) for isolated head injuries.

Conclusions

The major barriers to referral seem to be time to CT scanning and the level of “gate-keeping” at neurosurgical level. We believe the simplified neurosurgical referral pathway will give our isolated head injury patients the same rapid referral as our polytrauma patients.
PB4 Left before treatment-do patients know best?
Authors: Harper L , Collum N
Published: March 2012

Objective and Background

The percentage of patients who leave the Emergency Department (ED) before clinical assessment is one of the ED Quality Indicators. A rate of >5% is considered as a marker of potential risk, of overcrowding and long waits to be seen. The study objective is to establish our Left Before Treatment (LBT) rate and to review data trends in order that potential risks are identified.

Methods

A retrospective ED notes review from the Ulster Hospital ED during May and June 2011. The ED notes of all patients who did not wait for assessment were collected and hand-reviewed by the authors.

Results

There were 13 939 patient attendances to the ED during the 2-month study period. The Male: Female ratio was 0.9:1; mean age was 41 years, and 3305 (23%) were admitted to hospital. 342 (2.5%) patients LBT. Patients who LBT had a M: F ratio of 1.2:1; mean age of 34 years; and attended in the following pattern: 174 (51%) at the weekend; 90 (26%) on Monday or Tuesday (our busiest days). 171 (50%) attended when there was no ED Consultant present; 30 (9%) when there was also no middle grade. The LBT could be grouped into broad case-categories: Minor injury (22.8%), Medical (18.4%), Paediatric (13.2%), Head injuries (10.5%), atraumatic musculoskeletal (8.5%), Surgical (6.7%), unknown (5.8%). Mean time to triage was 21 min, 43 (12.5%) left before triage. 50 (14.6%) had investigations performed. 19 (38%) were abnormal; 1 (0.2%) patient required recall. 12 (3.5%) patients re-attended during the 2 months, some on multiple occasions.

Conclusion

The Ulster ED LBT rate for May/June 2011 was 2.5%, meeting the QI standard. Detailed review reveals that the rates of re-attending and of significant pathology are insignificant (both <0.1% total attendances). We confirm that when the LBT rate is low detailed review is unnecessary, as clinical risk is insignificant. We will re-audit this topic locally.