bluuebunny/crossref_metadata_2025_split huggingface dataset:
Large Eddy Simulation of High Reynolds Number Non-Reacting and Reacting JP8 Sprays With a Kerosene Surrogate and Detailed Chemistry
Authors: Bravo Luis , Wijeyakulasuriya Sameera , Pomraning Eric , Senecal P. K. , Kweon Chol Bum 
Published: January 2016

High-resolution single-plume JP-8 spray simulations have been performed to characterize detailed mixture formation process of high-pressure sprays for several common rail fuel injectors of interest to the Army. The first phase of the study involves examining the spray-induced turbulent mixing and global penetration parameters to present experimentally validated results across several computationally challenging length scales. Statistical convergence effects on the spray behavior and penetration profiles are presented by conducting several realizations for each injection case study. The second phase of the project adopts the grid-criteria approach developed for evaporating conditions to model turbulent combustion of a JP-8 reacting spray at compression-ignition engine conditions. A coupled Eulerian Lagrangian formulation is used to model the ensuing spray primary and secondary atomization regions using classical Kelvin Helmholtz - Rayleigh Taylor (KH-RT) wave type models. The flow turbulence subgrid scale microstructure is modeled via Dynamic Structure Large Eddy Simulation (DSLES) approach, largely resolving the anisotropic flow structures. The simulations are conducted across several fuel injector nozzle orifice dimensions ranging from 40–147 μm at a rail pressure of 1000 bar and typical compression-ignition engine operating condition of 900K and 60 bar, which is denoted as ECN Spray A. Liquid fuel physical properties are prescribed using a JP-8 surrogate mixture containing 80% n-decane and 20% trimethylbenzene (TMB) by volume.
The reacting gas phase kinetics is modeled using the Aachen mechanism [26–27] and a detailed chemistry approach of a kerosene surrogate mixture. Measurements from the Army Research Laboratory (ARL) Constant Pressure Flow (CPF) chamber provide global spray and combustion parameters for comparison, including spray penetration profiles, ignition delay and flame lift-of-lengths (LOL) for JP-8 fuels. The simulation results present validated non-reacting and reacting spray simulations (ignition delay agreed within 4% and flame LOL agreed within 5% of measured data) and provide insights into the atomization and mixing characteristics across several orifice dimensions.
Use of Adaptive Injection Strategies to Increase the Full Load Limit of RCCI Operation
Authors: Hanson Reed , Ickes Andrew , Wallner Thomas 
Published: January 2016

Dual-fuel combustion using port-injection of low reactivity fuel combined with direct injection of a higher reactivity fuel, otherwise known as Reactivity Controlled Compression Ignition (RCCI), has been shown as a method to achieve low-temperature combustion with moderate peak pressure rise rates, low engine-out soot and NOx emissions, and high indicated thermal efficiency. A key requirement for extending to high-load operation is moderating the reactivity of the premixed charge prior to the diesel injection. One way to accomplish this is to use a very low reactivity fuel such as natural gas. In this work, experimental testing was conducted on a 13L multi-cylinder heavy-duty diesel engine modified to operate using RCCI combustion with port injection of natural gas and direct injection of diesel fuel.
Engine testing was conducted at an engine speed of 1200 RPM over a wide variety of loads and injection conditions. The impact on dual-fuel engine performance and emissions with respect to varying the fuel injection parameters is quantified within this study.
The injection strategies used in the work were found to affect the combustion process in similar ways to both conventional diesel combustion and RCCI combustion for phasing control and emissions performance. As the load is increased, the port fuel injection quantity was reduced to keep peak cylinder pressure and maximum pressure rise rate under the imposed limits. Overall, the peak load using the new injection strategy was shown to reach 22 bar BMEP with a peak brake thermal efficiency of 47.6%.
Low Emissions Kit Development for a 1.5MW EMD GP20D Locomotive
Authors: Stoos Christopher R. , Guliaeff Alexander 
Published: January 2016

This paper describes the development, testing, and application of a low emissions upgrade kit for 1.5 MW EMD GP20D locomotives. Low emissions development focused on changes to fuel injection timing combined with the application of crank case ventilation system (CCV) and catalyzed diesel particulate filters (DPF). Composed of a porous cordierite ceramic material, the diesel particulate filters are specifically designed for entrapment of diesel particulates while allowing exhaust gases to flow through. Furthermore, the filters are coated with a proprietary catalyzed washcoat that promotes the oxidation of soot within the exhaust gas temperature range observed under normal engine operation. In addition to the low temperature oxidation of soot, the catalyzed filter also reduces carbon monoxide and unburned hydrocarbons.
The test locomotive used for this development, which is owned by CIT Rail, was powered by a recently rebuilt Caterpillar 3516B engine with a rated power of 1.5 MW (2,000 HP). Baseline exhaust emission testing was performed, followed by low emissions retrofit development. In combination with the CCV and new fuel injection calibrations, the DPF system netted significant emissions reductions. The result of the final low emissions upgrade kit was an EPA Tier 1+ certification, with emissions levels that were below EPA Tier 3 locomotive switch cycle standards for oxides of nitrogen (NOx) and below EPA Tier 4 switch cycle standards for hydrocarbons (HC), carbon monoxide (CO), particulate matter (PM), and smoke.
Effect of Fuel Injection Strategy on DPF Regeneration in Single Cylinder Diesel Engine
Authors: Yoon Sungjun , Kim Hongsuk , Kim Daesik , Park Sungwook 
Published: January 2016

Stringent emission regulations (e.g., Euro-6) force automotive manufacturers to equip DPF (diesel particulate filter) on diesel cars. Generally, post injection is used as a method to regenerate DPF. However, it is known that post injection deteriorates specific fuel consumption and causes oil dilution for some operating conditions. Thus, an injection strategy for regeneration becomes one of key technologies for diesel powertrain equipped with a DPF.
This paper presents correlations between fuel injection strategy and exhaust gas temperature for DPF regeneration. Experimental apparatus consists of a single cylinder diesel engine, a DC dynamometer, an emission test bench, and an engine control system. In the present study, post injection timing covers from 40 deg aTDC to 110 deg aTDC and double post injection was considered. In addition, effects of injection pressures were investigated. The engine load was varied from low-load to mid-load and fuel amount of post injection was increased up to 10mg/stk.
Oil dilution during fuel injection and combustion processes were estimated by diesel loss measured by comparing two global equivalences ratios; one is measured from Lambda sensor installed at exhaust port, the other one is estimated from intake air mass and injected fuel mass. In the present study, the differences in global equivalence ratios were mainly caused from oil dilution during post injection.
The experimental results of the present study suggest an optimal engine operating conditions including fuel injection strategy to get appropriate exhaust gas temperature for DPF regeneration. Experimental results of exhaust gas temperature distributions for various engine operating conditions were summarized.
In addition, it was revealed that amounts of oil dilution were reduced by splitting post injection (i.e., double post injection). Effects of injection pressure on exhaust gas temperature were dependent on combustion phasing and injection strategies.
Robust Sensing and Reversible Actuation Using Triblock Copolymer Stabilized Intradroplet Interfaces
Authors: Tamaddoni Nima , Taylor Graham J. , Sarles Stephen A. 
Published: January 2016

In this work, a recently developed method for forming copolymer-stabilized interfaces (CSI) between aqueous droplets is pursued to as a means to construct smart materials and systems. The ABA type copolymer employed consists of two hydrophilic (PEO) groups sandwiching a hydrophobic PDMS core. Aqueous droplets submerged in triblock copolymer (PEO-PDMS-PEO)-oil mixtures are rapidly coated in copolymer monolayers, however, unlike phospholipid-stabilized droplet interface bilayers (DIBs), electrical measurements reveal that there is no spontaneous formation of a “thinned” interface with droplet contact alone. The capacitance of the interface begins increasing significantly only upon application of sufficient voltage (>100mV), and capacitance then stabilizes within minutes. Further, the interfacial capacitance and area decreases when applied voltage is reduced back to 0mV, and droplets eventually return to their initial separated state. The fact that droplet adhesion and formation of the interface is voltage dependent and completely reversible clearly distinguishes a CSI from a DIB, and the novel polymer based interface is significantly more robust with average rupture potential of ≥ 800mV compared to 200–300mV with DIBs.
Durable and stable CSIs could feasibly be used in applications ranging from sensing and energy harvesting to mechanical actuation. To demonstrate, this work introduces a new version of the DIB based hair cell sensor, now replacing lipids with block copolymers to provide greater durability, stability, and resistance to rupture when subjected to airflow. We calculate the current generated by the vibrating membranes in DIBs and CSIs to study the influence of surfactant selection on the hair cell durability and the related airflow operation range. We conclude that the hair cell constructed using triblock copolymer, as opposed to a DIB, withstands higher nominal airflow speeds (45m/s) and higher applied bias voltages (i.e. 0.1–1V) without rupturing. The ability to apply higher voltages provides a means of tuning the hair-cell sensitivity. Separately, the results of initial trials demonstrate the possibility for voltage-controlled shape change using networks of droplets and CSIs. The ability to apply large voltages and induce change in interfacial area leads to rearrangement of the droplet networks due to conservation of volume. Several embodiments of possible actuators based on this mechanism are discussed. In concert, the various aspects of this work highlight the potential use of CSIs in developing novel, reliable smart materials for sensing and actuation.
Elastocaloric Cooling With Ni-Ti Based Alloys: Material Characterization and Process Variation
Authors: Schmidt Marvin , Ullrich Johannes , Wieczorek André , Frenzel Jan , Schütze Andreas , Eggeler Gunther , Seelecke Stefan 
Published: January 2016

Solid state refrigeration processes, such as magnetocaloric and electrocaloric refrigeration, have recently shown to be a promising alternative to conventional compression refrigeration. A new solid state elastocaloric refrigeration process using the latent heats within Shape Memory Alloys (SMA) could also hold potential in this field. This work investigates the elastocaloric effects in Ni-Ti-based superelastic Shape Memory Alloy (SMA) systems for use in an elastocaloric cooling processes. Ni-Ti alloys exhibits large latent heats and a small mechanical hysteresis, which may potentially lead to the development of an efficient environmentally friendly solid-state cooling system, without the need for ozone-depleting refrigerants. A systematic investigation of the SMA is conducted using a novel custom-built scientific testing platform specifically designed to measure cooling process related phenomena. This testing system is capable of performing tensile tests at high rates as well as measuring and controlling the solid-state heat transfer between SMA and heat source/heat sink.
Tests are conducted following a cooling process related training cycle where the material has achieved stabilized behavior. First, a characterization of the elastocaloric material properties is performed followed by an investigation of the material under cooling process conditions.
A comprehensive monitoring of the mechanical and thermal parameters enables the observation of temperature changes during mechanical cycling of the SMA at high strain rates. These observations can be used to study the rate dependent efficiency of the elastocaloric material.
The measurement of the temperature of both the heat source/heat sink and the SMA itself, as well as the required mechanical work during a running cooling process, reveals the influence of the operating conditions on the elastocaloric effect of the material.
Furthermore investigations of the process efficiency at different thermal boundary conditions (temperature of heat source/heat sink), indicates that the process is dependent on the boundary conditions which have to be controlled in order to optimize the efficiency.
Combined Simulation of the Closing Behavior of a Smart Hydrogel Micro-Valve
Authors: Mehner Philipp J. , Allerdißen Merle , Voigt Andreas , Marschner Uwe , Richter Andreas 
Published: January 2016

Smart hydrogel micro-valves are essential components of micro-chemo-mechanical fluid systems. These valves show a transistor-like behavior and are based on phase-changeable polymers. They can open and close micro-fluidic channels depending on chemical concentrations in the fluid. These highly complex systems are challenging to engineer and their development will advance faster if proper simulations take place beforehand.
A concept of how to simulate concentration-triggered, phase-changeable hydrogels is proposed. A simplified flow simulations will be presented to demonstrate the feasibility of this approach and to highlight geometrical problems. Based on the results, structurally more advanced models will be introduced with implemented multi-field solver interactions including thermal, mechanical and fluidic domains. The results of these models show the closing behavior of a micro-valve. The computed parameters of such valves are implemented into a circuit representation, which is capable of efficiently computing large scale micro-fluidic systems using an electric circuit simulator. These methods will help to predict, visualize and understand polymeric swelling behavior and demonstrate the performance of large-scale chip applications before any complex experiment is performed.
Further Insight on the Power Harvesting Capabilities of Magnetic Shape Memory Alloys
Authors: Guiel Roger , Dikes Jason L. , Ciocanel Constantin , Feigenbaum Heidi P. 
Published: January 2016

Magnetic shape memory alloys are a relatively new class of materials that are suitable for actuation, sensing, and power harvesting. The power harvesting capability comes from the change in magnetization that the material exhibits when internal martensitic variants change orientation.
In typical power harvesting tests, the material is loaded with axial compression in the presence of a bias magnetic field applied normal to the compressive loading direction. However, previous results suggest that having a component of the bias magnetic field applied axially, parallel to the compressive stress, can increase the power output of MSMAs.
Furthermore, most of the MSMAs power harvesting results reported to date focused on the open circuit voltage that the material can generate during cyclic loading. However, this information is not indicative of the true power harvesting capability of the material and one has to focus on the power output of the material instead.
This paper presents voltage trends and power output data for a MSMA sample exposed simultaneously to a cyclic compressive stress and bi-axial magnetic field.
Social contacts, vaccination decisions and influenza in Japan
Authors: Ibuka Yoko , Ohkusa Yasushi , Sugawara Tamie , Chapman Gretchen B , Yamin Dan , Atkins Katherine E , Taniguchi Kiyosu , Okabe Nobuhiko , Galvani Alison P 
Published: January 2016

BackgroundContact patterns and vaccination decisions are fundamental to transmission dynamics of infectious diseases. We report on age-specific contact patterns in Japan and their effect on influenza vaccination behaviour.MethodsJapanese adults (N=3146) were surveyed in Spring 2011 to assess the number of their social contacts within a 24 h period, defined as face-to-face conversations within 2 m, and gain insight into their influenza-related behaviour. We analysed the duration and location of contacts according to age. Additionally, we analysed the probability of vaccination and influenza infection in relation to the number of contacts controlling for individual's characteristics.ResultsThe mean and median reported numbers of daily contacts were 15.3 and 12.0, respectively. School-aged children and young adults reported the greatest number of daily contacts, and individuals had the most contacts with those in the same age group. The age-specific contact patterns were different between men and women, and differed between weekdays and weekends. Children had fewer contacts between the same age groups during weekends than during weekdays, due to reduced contacts at school. The probability of vaccination increased with the number of contacts, controlling for age and household size. Influenza infection among unvaccinated individuals was higher than for those vaccinated, and increased with the number of contacts.ConclusionsContact patterns in Japan are age and gender specific. These contact patterns, as well as their interplay with vaccination decisions and infection risks, can help inform the parameterisation of mathematical models of disease transmission and the design of public health policies, to control disease transmission.
Firm Risk-Taking and CEO Visibility
Authors: Liu Yixin , Zhang Yilei , Jiraporn Pornsit 
Published: January 2016

This paper investigates the relationship between CEO visibility and corporate risk-taking. The empirical results show that more visible CEOs tend to take more risk. A one-standard-deviation shock in the CEOs media exposure results in a 6.53% rise in total risk. We further investigate the channels of risk-taking activities and find that more visible CEOs seek more R&D investments. The positive effect of CEO visibility on firm risk policies is clearly of concern to bondholders. Consistent with this view, we report that CEO visibility has a significant negative effect on firm credit ratings. Our results highlight the importance of CEO visibility on a crucial corporate outcome — the extent of corporate risk-taking.
Aspirin Reduces Plasma Concentrations of the Oncometabolite 2-Hydroxyglutarate: Results of a Randomized, Double-Blind, Crossover Trial
Authors: Liesenfeld David B. , Botma Akke , Habermann Nina , Toth Reka , Weigel Christoph , Popanda Odilia , Klika Karel D. , Potter John D. , Lampe Johanna W. , Ulrich Cornelia M. 
Published: January 2016

AbstractBackground: Aspirin use is an effective strategy for the chemoprevention of colorectal cancer, even at low doses. However, in order to implement aspirin interventions, risk–benefit balances and biologic mechanisms need to be better defined; to further this aim, we used a metabolomics approach.Methods: We metabolically profiled 40 healthy, nonsmoking men and women ages 20 to 45 years enrolled in a randomized, double-blind, crossover trial of 325 mg aspirin/day over a period of 60 days. Gas and liquid chromatography–mass spectrometry were used to comprehensively profile participants' plasma samples after aspirin and placebo interventions.Results: A total of 363 metabolites, covering most human biochemical pathways, were measured. Compared with placebo-treated participants, plasma concentrations of the oncometabolite 2-hydroxyglutarate (R+S) decreased after aspirin treatment in both men and women (P = 0.005). This signal proved robust during 20-fold random splitting of the data using 80% of the samples in each split. We subsequently performed functional follow-up studies using targeted, enantiospecific detection in human colorectal cancer cell lines and observed an aspirin-induced reduction of (R)-2-hydroxyglutarate. We further showed that salicylate, the primary aspirin metabolite, inhibits the hydroxyacid–oxoacid transhydrogenase mediated production of (R)-2-hydroxyglutarate, thereby providing mechanistic evidence for the clinically observed effects of aspirin on total-2-hydroxyglutarate.Conclusions: Using a metabolomics approach with functional follow-up, we propose that a decrease in the oncometabolite (R)-2-hydroxyglutarate may identify an additional mechanism for aspirin or its metabolites in cancer prevention.Impact: Reduction of the oncometabolite (R)-2-hydroxyglutarate identifies a novel, non–COX-inhibition-mediated mechanism of aspirin. Cancer Epidemiol Biomarkers Prev; 25(1); 180–7. ©2015 AACR.
Frequency and Predictors of Internal Mammary Artery Graft Failure and Subsequent Clinical Outcomes
Authors: Harskamp Ralf E. , Alexander John H. , Ferguson T. Bruce , Hager Rebecca , Mack Michael J. , Englum Brian , Wojdyla Daniel , Schulte Phillip J. , Kouchoukos Nicholas T. , de Winter Robbert J. , Gibson C. Michael , Peterson Eric D. , Harrington Robert A. , Smith Peter K. , Lopes Renato D. 
Published: January 2016

Background—
The internal mammary artery (IMA) is the preferred conduit for bypassing the left anterior descending (LAD) artery in patients undergoing coronary artery bypass grafting. Systematic evaluation of the frequency and predictors of IMA failure and long-term outcomes is lacking.

Methods and Results—
The Project of Ex-vivo Vein Graft Engineering via Transfection (PREVENT) IV trial participants who underwent IMA-LAD revascularization and had 12- to 18-month angiographic follow-up (n=1539) were included. Logistic regression with fast false selection rate methods was used to identify characteristics associated with IMA failure (≥75% stenosis). The relationship between IMA failure and long-term outcomes, including death, myocardial infarction, and repeat revascularization, was assessed with Cox regression. IMA failure occurred in 132 participants (8.6%). Predictors of IMA graft failure were LAD stenosis <75% (odds ratio, 1.76; 95% confidence interval, 1.19–2.59), additional bypass graft to diagonal branch (odds ratio, 1.92; 95% confidence interval, 1.33–2.76), and not having diabetes mellitus (odds ratio, 1.82; 95% confidence interval, 1.20–2.78). LAD stenosis and additional diagonal graft remained predictive of IMA failure in an alternative model that included angiographic failure or death before angiography as the outcome. IMA failure was associated with a significantly higher incidence of subsequent acute (<14 days of angiography) clinical events, mostly as a result of a higher rate of repeat revascularization.

Conclusions—
IMA failure was common and associated with higher rates of repeat revascularization, and patients with intermediate LAD stenosis or with an additional bypass graft to the diagonal branch had increased risk for IMA failure. These findings raise concerns about competitive flow and the benefit of coronary artery bypass grafting in intermediate LAD stenosis without functional evidence of ischemia.

Clinical Trial Registration—

URL:
http:/www.clinicaltrials.gov
. Unique identifier: NCT00042081.