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To accurately model the Direct Injection Spark Ignition (DISI) combustion process, it is important to account for the effects of the spark energy discharge process. The proximity of the injected fuel spray and spark electrodes leads to steep gradients in local velocities and equivalence ratios, particularly under cold-start conditions when multiple injection strategies are employed. The variations in the local properties at the spark plug location play a significant role in the growth of the initial flame kernel established by the spark and its subsequent evolution into a turbulent flame. In the present work, an ignition model is presented that is compatible with the G-Equation combustion model, which responds to the effects of spark energy discharge and the associated plasma expansion effects. The model is referred to as the Plasma Velocity on G-surface (PVG) model, and it uses the G-surface to capture the early kernel growth. The model derives its theory from the Discrete Particle Ignition (DPIK) model, which accounts for the effects of electrode heat transfer, spark energy, and chemical heat release from the fuel on the early flame kernel growth. The local turbulent flame speed has been calculated based on the instantaneous location of the flame kernel on the Borghi-Peters regime diagram. The model has been validated against the experimental measurements given by Maly and Vogel,1 and the constant volume flame growth measurements provided by Nwagwe et al.2 Multi-cycle simulations were performed in CONVERGE3 using the PVG ignition model in combination with the G-Equation-based GLR4 model in a RANS framework to capture the combustion characteristics of a DISI engine. Good agreements with the experimental pressure trace and apparent heat-release rates were obtained. Additionally, the PVG ignition model was observed to substantially reduce the sensitivity of the default G-sourcing ignition method employed by CONVERGE.

Developing a profound understanding of the combustion characteristics of the cold-start phase of a Direct Injection Spark Ignition (DISI) engine is critical to meeting increasingly stringent emissions regulations. Computational Fluid Dynamics (CFD) modeling of gasoline DISI combustion under normal operating conditions has been discussed in detail using both the detailed chemistry approach and flamelet models (e.g. the G-Equation). However, there has been little discussion regarding the capability of the existing models to capture DISI combustion under cold-start conditions. Accurate predictions of cold-start behavior involves the efficient use of multiple models - spray modeling to capture the split injection strategies, models to capture the wall-film interactions, ignition modeling to capture the effects of retarded spark timings, combustion modeling to accurately capture the flame front propagation, and turbulence modeling to capture the effects of decaying turbulent kinetic energy. The retarded spark timing helps to generate high heat flux in the exhaust for the faster catalyst light-off during cold-start. However, the adverse effect is a reduced turbulent flame speed due to decaying turbulent kinetic energy. Accordingly, developing an understanding of the turbulence-chemistry interactions is imperative for accurate modeling of combustion under cold-start conditions. In the present work, combustion characteristics during the cold-start, fast-idle phase is modeled using the G-Equation flamelet model and the RANS turbulence model. The challenges associated with capturing the turbulent-chemistry interactions are explained by tracking the flame front travel along the Borghi-Peters regime diagram. In this study, a modified version of the G-Equation combustion model for capturing cold-start flame travel is presented.

Objective: To assess the association between specific heart diseases and suicide. Design: Nationwide retrospective cohort study. Participants: A total of 7 298 002 individuals (3 640 632 males and 3 657 370 females) aged ≥15 years and living in Denmark during 1980–2016. Main outcome measures: Incidence rate ratios (IRR) with 95% confidence intervals. In multivariate analysis, we adjust for sex, period, age group, living status, income level, Charlson Comorbidity Index, psychiatric disorders prior to heart disease and self-harm prior to heart disease. Results: Excess suicide rate ratios were found for following disorders: heart failure (IRR: 1.48; 95% CI: 1.38–1.58); cardiomyopathy (IRR: 1.41; 95% CI: 1.16–1.70); acute myocardial infarction (IRR: 1.28; 95% CI: 1.21–1.36); cardiac arrest with successful resuscitation (IRR: 4.75; 95% CI: 3.57–6.33); atrial fibrillation and flutter (IRR: 1.42; 95% CI: 1.32–1.52); angina pectoris (IRR: 1.19; 95% CI: 1.12–1.26); and ventricular tachycardia (IRR: 1.53; 95% CI: 1.20–1.94). A higher rate of suicide was noted during the first 6 months after the diagnosis of heart failure (IRR: 2.38; 95% CI: 2.04–2.79); acute myocardial infarction (IRR: 2.24; 95% CI: 1.89–2.66); atrial fibrillation and flutter (IRR: 2.70; 95% CI: 2.30–3.18); and angina pectoris (IRR: 1.83; 95% CI: 1.53–2.19) when compared to later. Conclusion: Several specific disorders were found to be associated with elevated rates of suicide. Additionally, we found temporal associations with higher suicide rates in the first time after diagnosis. Our results underscore the importance of being attentive towards psychological distress in individuals with heart disease.

The aim of this review is to summarise the status of autoimmune pancreatitis (AIP), which is a rare disease, occasionally misdiagnosed as pancreatic cancer.AIP consists of two distinct types, which differ in histopathology, association with other diseases and age of onset. Clinically, it is characterised by obstructive jaundice and abdominal pain. The disease shows rapid response to steroids. Rituximab can also be used as induction therapy. Often long-term treatment is necessary to maintain remission.

The aim of this review is to summarise the status of autoimmune pancreatitis (AIP), which is a rare disease, occasionally misdiagnosed as pancreatic cancer. AIP consists of two distinct types, which differ in histopathology, association with other diseases and age of onset. Clinically, it is characterised by obstructive jaundice and abdominal pain. The disease shows rapid response to steroids. Rituximab can also be used as induction therapy. Often long-term treatment is necessary to maintain remission.

In this study, spray characteristics from a single-hole gasoline direct injection injector with nozzle diameters of 0.14 mm and 0.2 mm were investigated. High-speed macroscopic and microscopic imaging techniques were applied to record the overall spray structure and the initial fuel spray behavior. The injection pressure ranged from 50 bar to 350 bar, and the ambient pressure was kept constant at 1 bar. Several semi-empirical models for predicting spray penetration at non-evaporating conditions were investigated, including models by Dent, Hiroyasu and Arai, and Naber and Siebers. Results showed that the Naber and Siebers equation demonstrated the best match with the experimental data. Both the initial and global spray penetration were well predicted. The spray penetration can be divided into two regions based on the relationship between spray penetration and injection time, namely the regions before and after breakup, and the transitional point was defined as the breakup point. Higher fuel pressures resulted in shorter breakup time and length for the injector with the smaller nozzle diameter, and the injector with larger nozzle diameter produced shorter breakup time and longer breakup length. A linear relationship was identified between the initial spray penetration and injection time at all fuel pressures, which indicates the initial spray tip velocity can be treated as constant at each fuel pressure. The ratio between the slope of experimental initial spray penetration and average flow velocity (based on static flow rate measurements) was around 0.9 at all fuel pressures for the injector with 0.14 mm nozzle diameter. Consequently, the average flow velocity obtained based on the static flow rate at each fuel pressure can be used to accurately predict the initial jet velocity.

Low-energy recoil events in Ti3SiC2 are studied using ab initio molecular dynamics simulations. We find that the threshold displacement energies are orientation dependent because of anisotropic structural and/or bonding characteristic. For Ti and Si in the Ti–Si layer with weak bonds that have mixed covalent, ionic, and metallic characteristic, the threshold displacement energies for recoils perpendicular to the basal planes are larger than those parallel to the basal planes, which is an obvious layered-structure-related behavior. The calculated minimum threshold displacement energies are 7 eV for the C recoil along the [0001¯] direction, 26 eV for the Si recoil along the [21¯1¯0] direction, 24 eV for the Ti in the Ti–C layer along the [21¯1¯0] direction and 23 eV for the Ti in the Ti–Si layer along the [21¯1¯0] direction. These results will advance the understanding of the cascade processes of Ti3SiC2 under irradiation and are expected to yield new perspective on the MAX phase family that includes more than 100 compounds.

The need for fast and comprehensive characterization of biocatalysts has pushed the development of new screening platforms based on microfluidics, capable of monitoring several parameters simultaneously, with new configurations of liquid handling, sample treatment and sensing. Modular microfluidics allows the integration of these newly developed approaches in a more flexible way towards increasing applicability of the microfluidic chips to different types of biocatalysts and reactions. A highly relevant operation in such a system is biocatalyst inactivation, which can enable the precise control of reaction time by avoiding the continuation of the reaction in another module or connecting tubes. Such control is important when different modules of reactors and/or sensing units are used and changed frequently. Here we describe the development, characterization and application of a module for rapid enzyme inactivation. The thermal inactivation platform developed is compared with a standard benchtop ThermoMixer in terms of inactivation efficiency for glucose oxidase and catalase. A higher activity loss was observed for enzyme inactivation under flow conditions (inactivation achieved at 120 s residence time at 338 K and 20 s residence time at 353 K) which indicated a high heat transfer to the fluid under dynamic conditions. Moreover, partial deactivation of the enzymes was observed for the continuous thermal inactivation module, when activity measurements were performed after 1 and 2 days following inactivation. The thermal inactivation unit presented can be easily integrated into modular microfluidic platforms and can be a useful addition for enzyme characterization and screening.

The effects of ethanol on reducing the particulate emissions of a direct injection spark ignition (DISI) engine were investigated using a single-cylinder, optically accessible engine. Neat anhydrous ethanol was compared with a baseline fuel of reference grade gasoline. A high speed camera was used to record crank-angle resolved in-cylinder images of the fuel spray, combustion, and thermal radiation from the soot formed for the engine operating conditions studied. Particulate emissions in the engine exhaust gas were also measured using opacity measurements (i.e., using a smoke meter). All experiments were conducted at the same load conditions with a net indicated mean effective pressure of IMEPnet ≈ 5.5 bar and an intake manifold absolute pressure of 76 kPa. The engine speed was fixed at 1500 rpm, and the fuel injection duration was controlled to achieve stoichiometric combustion. Spark timing was adjusted to target combustion phasing (CA50) of 8° aTDC. The effects of engine coolant temperature and fuel in...

Unanswered questions remain in determining which high-risk node-negative colon cancer (CC) cohorts benefit from adjuvant therapy and how it may differ in an equal access population. Machine-learned Bayesian Belief Networks (ml-BBNs) accurately estimate outcomes in CC, providing clinicians with Clinical Decision Support System (CDSS) tools to facilitate treatment planning. We evaluated ml-BBNs ability to estimate survival and recurrence in CC. We performed a retrospective analysis of registry data of patients with CC to train–test–crossvalidate ml-BBNs using the Department of Defense Automated Central Tumor Registry (January 1993 to December 2004). Cases with events or follow-up that passed quality control were stratified into 1-, 2-, 3-, and 5-year survival cohorts. ml-BBNs were trained using machine-learning algorithms and k-fold crossvalidation and receiver operating characteristic curve analysis used for validation. BBNs were comprised of 5301 patients and areas under the curve ranged from 0.85 to 0.90. Positive predictive values for recurrence and mortality ranged from 78 to 84 per cent and negative predictive values from 74 to 90 per cent by survival cohort. In the 12-month model alone, 1,132,462,080 unique rule sets allow physicians to predict individual recurrence/mortality estimates. Patients with Stage II (N0M0) CC benefit from chemotherapy at different rates. At one year, all patients older than 73 years of age with T2–4 tumors and abnormal carcinoembryonic antigen levels benefited, whereas at five years, all had relative reduction in mortality with the largest benefit amongst elderly, highest T-stage patients. ml-BBN can readily predict which high-risk patients benefit from adjuvant therapy. CDSS tools yield individualized, clinically relevant estimates of outcomes to assist clinicians in treatment planning.

The effects of ethanol on spray development and wall impingement of a direct injection spark ignition (DISI) engine was investigated using high-speed imaging of the fuel spray in an optically-accessible engine. Neat anhydrous ethanol (E100), reference grade gasoline (E0) and a 50% blend (by volume) of gasoline and ethanol (E50) were used in the study. The experiments were conducted using continuous firing conditions for an intake manifold absolute pressure of 57 kPA, and engine speed of 1500 RPM. Retarded fuel injection timing was used (with start of injection at 250 °bTDC) to isolate the effects of cylinder wall impingement, and lean fuel-to-air ratios (ϕ=0.8–0.9) were used to minimize sooting and coating of the transparent cylinder liner. The effects of three engine coolant temperatures (25, 60 and 90 °C) and two fuel rail pressures (100 and 150 bar) on the features of the spray and the spray interaction with the wall were studied for the different fuels. Quantitative metrics were defined to analyze the spatial features of the spray related to wall impingement. Gasoline (E0) sprays exhibited higher sensitivity to coolant temperature compared to ethanol (E100) in terms of the shape of the spray and wall impingement. Higher fuel injection pressure increased the spray tip penetration rate and fuel impingement with the wall for E0 and E100, despite creating wider plume angles of the fuel sprays.Copyright © 2015 by ASME

Sinkholes in Florida pose significant geotechnical, engineering, and hydrogeological challenges for using the land in constructive ways. In some instances, the sinkholes may prove unstable, thus limiting the overburden stress that can be applied. Additionally, the sinkholes may provide a conduit for accelerated contaminant transport from surface activities. In this case study, we use electrical resistivity tomography (ERT) to understand the scope of sinkhole activity under a planned landfill. As part of their application, the landfill permit applicant submitted a dense network of parallel, twodimensional electrical resistivity profiles as described in the following. We provided an alternative, three dimensional analysis of this data set to enhance detection of subsurface sinkhole targets. Eighty five parallel resistivity lines spaced 6m (20ft) apart were coalesced into a large three-dimensional resistivity model to map the 14 hectare (35 acre) site. The results revealed that resistive sand-filled sinkholes could extend at least 30m (100ft) below ground surface with a diameter that ranged from 30 to 100m (100-300ft). The host conductive limestone was shown to have a complex undulating topography with eroded pinnacles. Using cone penetrometer technology (CPT), the edge of the limestone pinnacles were also shown to have significant raveling, which coincided with a narrow range of resistivity values. The implications of the correlation between direct characterization using CPT and indirect characterization with ERT suggest that raveling could cover as much as 17% of the site. Based on these findings, the site was determined to be ill suited for landfill construction.

Toluene fuel-tracer laser-induced fluorescence is employed to quantitatively measure the equivalence ratio distributions in the cylinder of a light-duty diesel engine operating in a low-temperature, high-EGR, and early-injection operating mode. Measurements are made in a non-combusting environment at crank angles capturing the mixture preparation period: from the start-of-injection through the onset of high-temperature heat release. Three horizontal planes are considered: within the clearance volume, the bowl rim region, and the lower bowl. Swirl ratio and injection pressure are varied independently, and the impact of these parameters on the mixture distribution is correlated to the heat release rate and the engine-out emissions. As the swirl ratio or injection pressure is increased, the amount of over-lean mixture in the upper central region of the combustion chamber, in the bowl rim region and above, also increases. Unexpectedly, increased injection pressure results in a greater quantity of over-rich mixture within the squish volume.

e14500 Background: Unanswered questions remain regarding treatment efficacy in colon cancer (CC), especially those determining high-risk node-negative cohorts that may benefit from adjuvant therapy. We sought to evaluate the use of machine learning and classification modeling to estimate survival and recurrence in CC. Methods: We used the Department of Defense Automated Central Tumor Registry (ACTUR) to identify primary CC patients treated between January 1993 and December 2004. Cases with events or follow-up that passed quality control were stratified into one-, two-, three-, and five-year survival cohorts. ml-BBNs were trained using machine-learning algorithms and k-fold cross-validation, and receiver operating characteristic (ROC) curve analysis used for validation. Results: There were 5,301 cases stratified into cohorts. Survival cohort Areas-Under-the-Curve (AUCs) ranged from 0.85–0.90, positive-predictive-values (PPVs) for recurrence and mortality ranged from 78-84% and negative-predictive-values (NPVs) from 74-90%. Cross-validation showed that the ml-BBNs produce robust individual estimates of recurrence (p