bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of a High-Pressure, High-Temperature, Optically Accessible Continuous-Flow Vessel for Fuel-Injection Experiments
Authors: James Kemar C. , Wang Jin , Morris Zackery B. , Maynard Michael C. , Fisher Brian T. 
Published: February 2014

The focus of this work was to develop a continuous-flow vessel with extensive optical access for characterization of engine-relevant fuel-injection and spray processes. The spray chamber was designed for non-reacting experiments at pressures up to 1380 kPa (200 psi) and temperatures up to 200°C. Continuous flow of inert “sweep gas” enables acquisition of large statistical data samples and thus potentially enables characterization of stochastic spray processes. A custom flange was designed to hold a common-rail diesel injector, with significant flexibility to accommodate other injectors and injector types in the future. This flexibility, combined with the continuous flow through the chamber, may enable studies of gas-turbine direct-injection spray processes in the future. Overall, the user can control and vary: injection duration, injection pressure, sweep-gas temperature, sweep-gas pressure, and sweep-gas flow rate. The user also can control frequency of replicate injections.
There are four flat windows installed orthogonally on the vessel for optical access. Optical data, at present, include global spray properties such as liquid-phase fuel penetration and cone angle. These measurements are made using a high-speed spray-visualization system (up to 100 kHz) consisting of a fast-pulsed LED (light emitting diode) source and a high-speed camera. Experimental control and data acquisition have been set up and synchronized using custom LabVIEW programs. The culmination of this development effort was an initial demonstration experiment to capture high-speed spray-visualization movies of n-heptane injections to determine liquid-phase fuel penetration length (i.e., liquid length) and spray cone angle. In this initial experiment, fuel-injection pressure was ∼120 MPa (1200 bar) and the injection command-pulse duration was 800 μs. At room conditions, liquid length and nominal spray cone angle were ∼170 mm and ∼14.5°, respectively. In contrast, with air flow in the chamber at 100 psi and 100°C, liquid length was considerably shorter at ∼92 mm and spray cone angle was wider at ∼16.5°. Future experiments will include the continuation of these measurements for a wider range of conditions and fuels, extension of high-speed imaging to vapor-phase fuel penetration using schlieren imaging techniques, and detailed characterization of spray properties near the injector nozzle and near the liquid length.
Analysis of Aluminum and Steel Pistons: Comparison of Friction, Piston Temperature, and Combustion
Authors: Schreer Kai , Roth Ingo , Schneider Simon , Ehnis Holger 
Published: February 2014

While steel pistons have been in use for a long time in commercial vehicle diesel engines, the first series production applications for passenger car diesel engines are currently imminent. The main reason for the use of steel pistons in high speed diesel engines is not, as maybe initially hypothesized, the increasing requirements on the component strength due to increasing mechanical loads, but rather challenges based on the actual CO2-legislation. The increasing requirements to reduce the fuel consumption necessitate new innovative technologies. The imminent penalties for exceeding the prescribed CO2 emissions seem to make the steel piston a viable alternative today, despite its higher manufacturing costs. So far, the CO2-benefits using steel pistons were mainly ascribed to the reduced friction between piston and cylinder liner due to no thermal interference.
Fuel consumption measurements at vehicle manufacturer and research institutes hypothesize also an influence of the steel piston on the thermodynamic efficiency. MAHLE uses engine tests to investigate one piston variant made of aluminum (series production piston with cooled ring carrier) and one of steel (MAHLE TopWeld) in a detailed system comparison. Using a fully indicated engine, a combustion process analysis is performed and used as the basis for a loss analysis. The engine set-up parameters can be adjusted fully variable using a flexible ECU. The effect that the piston variant has on the combustion process is captured and balanced, e.g., by adjusting the parameters to obtain identical emissions. The analysis records the potential of the variants for each engine operating map area. The thermal conditions for the piston and the piston wall temperature on the combustion chamber side are varied over a wide range using a conditioning device for piston cooling. The influence of this intervention on the thermal load of the piston and the combustion and also the influence of different combustion mappings is measured directly by telemetric piston temperature measurement. MAHLE recently completed a system comparison [3] between aluminum and steel pistons with detailed measurements on a fully indicated engine, covering friction and temperature behavior as well as influences on combustion.
Analysis and Modelling of the Transient Thermal Behaviour of Automotive Turbochargers
Authors: Burke Richard D. 
Published: February 2014

Turbochargers are a key technology to deliver fuel consumption reductions on future internal combustion engines. However, the current industry standard modeling approaches assume the turbine and compressor operate under adiabatic conditions. Although some state of the art modeling approaches have been presented for simulating the thermal behavior, these have focused on thermally stable conditions. In this work, an instrumented turbocharger was operated on a 2.2L Diesel engine and in parallel a one-dimensional lumped capacity thermal model was developed. For the first time this paper presents analysis of experimental and modeling results under dynamic engine operating conditions.
Engine speed and load conditions were varied to induce thermal transients with turbine inlet temperatures ranging from 200–800°C; warm-up behavior from 25°C ambient was also studied. Following a model tuning process based on steady operating conditions, the model was used to predict turbine and compressor gas outlet temperatures, doing so with an RMSE of 8.4°C and 7.1°C respectively. On the turbine side, peak heat losses from the exhaust gases were observed to be up to double those observed under thermally stable conditions due to the heat accumulation in the structure. During warm-up, the model simplifications did not allow for accurate modeling of compressor, however on the turbine side gas temperature predictions errors were reduced from 150°C to around 40°C. The main benefits from the present modeling approach appear to be in turbine outlet temperature prediction, however modeling improvements are identified for future work.
Automatic Combustion Phase Calibration With Extremum Seeking Approach
Authors: Corti Enrico , Mancini Giorgio , Forte Claudio , Moro Davide 
Published: February 2014

Combustion control is assuming a crucial role in reducing engine tailpipe emissions and maximizing performance. The number of actuations influencing the combustion is increasing, and, as a consequence, the calibration of control parameters is becoming challenging. One of the most effective factors influencing performance and efficiency is the combustion phasing: for gasoline engines control variables such as Spark Advance (SA), Air-to-Fuel Ratio (AFR), Variable Valve Timing (VVT), Exhaust Gas Recirculation (EGR) are mostly used to set the combustion phasing.
The optimal control setting can be chosen according to a target function (cost or merit function), taking into account performance indicators, such as Indicated Mean Effective Pressure (IMEP), Brake Specific Fuel Consumption (BSFC), pollutant emissions, or other indexes inherent to reliability issues, such as exhaust gas temperature, or knock intensity.
Many different approaches can be used to reach the best calibration settings: Design Of Experiment (DOE) is a common option when many parameters influence the results, but other methodologies are in use: some of them are based on the knowledge of the controlled system behavior, by means of models that are identified during the calibration process.
The paper proposes the use of a different concept, based on the extremum seeking approach. The main idea consists in changing the values of each control parameter at the same time, identifying its effect on the monitored target function, allowing to shift automatically the control setting towards the optimum solution throughout the calibration procedure. An original technique for the recognition of control parameters variations effect on the target function is introduced, based on spectral analysis.
The methodology has been applied to data referring to different engines and operating conditions, using IMEP, exhaust temperature and knock intensity for the definition of the target function, and using SA and AFR as control variables. The approach proved to be efficient in reaching the optimum control setting, showing that the optimal setting can be achieved rapidly and consistently.
Virtual Design of an Industrial, Large-Bore, Spark-Ignited, Natural Gas, Internal Combustion Engine for Reduction of Regulated Pollutant Emissions
Authors: Etcheverry John , Patterson Mark , Grauer Diana 
Published: February 2014

The natural gas industry has long depended on large bore, two-stroke cycle, spark-ignited, gas-powered, reciprocating engines to move gas from the well to the pipeline and downstream. As regulations governing the pollutant emissions from these engines are tightened the industry is turning to the engine OEMs for a solution.
The challenge of further reducing engine emissions is not a new task to the industry. However, as the requirements placed on the engines are further restricted, the technology required to achieve these goals becomes more advanced, along with the required tools and technology to create it. New predictive tools have been created and have become more powerful and capable as computer software and hardware becomes more advanced, enabling engineers to create more complex designs and to do so quickly and at lower cost, all of which may not have been possible previously. This paper investigates methods used in designing the Ajax 2800 series, which is a large bore, two-stroke cycle, gas-powered, reciprocating engine and the improvements in emissions that resulted from the application of these methods.. Solutions to overcoming the challenges encountered during the process will also be presented.
Effect of Volatiles on Soot Based Deposit Layers
Authors: Salvi Ashwin , Hoard John , Bieniek Mitchell , Abarham Mehdi , Styles Dan , Assanis Dionissios 
Published: February 2014

The implementation of exhaust gas recirculation (EGR) coolers has recently been a widespread methodology for engine in-cylinder NOX reduction. A common problem with the use of EGR coolers is the tendency for a deposit, or fouling layer to form through thermophoresis. These deposit layers consist of soot and volatiles and reduce the effectiveness of heat exchangers at decreasing exhaust gas outlet temperatures, subsequently increasing engine out NOX emission.
This paper presents results from a novel visualization rig that allows for the development of a deposit layer while providing optical and infrared access. A 24-hour, 379 micron thick deposit layer was developed and characterized with an optical microscope, an infrared camera, and a thermogravimetric analyzer. The in-situ thermal conductivity of the deposit layer was calculated to be 0.047 W/mK. Volatiles from the layer were then evaporated off and the layer reanalyzed. Results suggest that volatile bake-out can significantly alter the thermo-physical properties of the deposit layer and hypotheses are presented as to how.
Tailor Made Biofuels: Effect of Fuel Properties on the Soot Microstructure and Consequences on Particle Filter Regeneration
Authors: Bhardwaj Om Parkash , Lüers Bernhard , Kolbeck Andreas F. , Koerfer Thomas , Kremer Florian , Pischinger Stefan , von Berg Angelika , Roth Georg 
Published: February 2014

In recent years a lot of effort has been made to understand the phenomena of Diesel Particulate Filter (DPF) regeneration processes but less attention has been paid to understand the influence of fuel properties on soot reactivity and its consequence on the DPF regeneration behavior.
Within the Cluster of Excellence “Tailor-Made Fuels from Biomass (TMFB)” at RWTH Aachen University, the Institute for Combustion Engines carried out a detailed investigation program to explore the potential of future biofuel candidates for optimized combustion systems. These new biofuels are being developed to realize partially homogeneous low-temperature combustion, in order to reduce the emission and fuel consumption to meet future requirements. The chemical structure of these new fuels may impact the thermal decomposition chemistry and hence the in-cylinder particulate formation conditions. This work fundamentally focusses the influence of fuel properties on particulate matter reactivity and, thereby, the regeneration behavior of the diesel particulate filters (DPF).
The experiments for particulate measurements and analysis were conducted, under constant engine operating conditions, on a EURO 6 compliant High Efficiency Combustion System (HECS) fuelled with petroleum based diesel fuel as baseline and today’s biofuels like FAME and Fischer Tropsch fuels as well as potential biomass derived fuel candidates being researched in TMFB.
Several different methods were used for analysis of mass, composition, structure and spectroscopic parameters of the soot. The graphitic microstructure visible with high resolution transmission electron microscopy (HRTEM) was compared to the results of X-Ray diffraction (XRD), optical light absorption measurement and elementary analysis of samples.
The results indicate that combustion with increasing fuel oxygenation produces decreasing engine-out particulate emissions. The ranking of activation energies of soot oxidation analysis from LGB experiments correspond well with the ranking of the soot physico-chemical properties. In comparison to petroleum based diesel fuel, the reduction of engine out soot emission by a factor of five with the use of the future biomass derived fuel candidate was accompanied by ten times reduction of the soot volume based absorption coefficient and two times reduction of carbon to hydrogen ratio. As a result of it, the activation energy of soot oxidation in DPF reduced by ∼ 10 KJ/mol. The reduced engine out soot emission and increased reactivity of the soot from the future biomass derived fuel candidate could cause a significant reduction of thermal DPF regenerations.
A Comparison of Valving Strategies Appropriate for Multi-Mode Combustion Within a Downsized Boosted Automotive Engine: Part A — High Load Operation Within the SI Combustion Regime
Authors: Shingne Prasad S. , Gerow Matthew S. , Triantopoulos Vassilis , Bohac Stanislav V. , Martz Jason B. 
Published: February 2014

As future downsized boosted engines may employ multiple combustion modes, the goal of the current work is the definition of valving strategies appropriate for moderate to high load spark ignition (SI) combustion and for spark assisted compression ignition (SACI) combustion at low to moderate loads for an engine with variable valve timing capability and fixed camshaft profiles. The dilution and unburned gas temperature requirements for SACI combustion can be markedly different from those of SI; therefore it is important to ensure that a given valving strategy is appropriate for operation within both regimes. This paper compares one dimensional (1D) thermodynamic simulations of rated engine operation with positive valve overlap (PVO) and a baseline negative valve overlap (NVO) camshaft design in a boosted automotive engine with variable valve timing capability. Several peak lifts and valve open durations are investigated to guide the down-selection of camshaft profiles for further evaluation under SACI conditions in a companion paper.
While the results of this study are engine specific, rated performance predictions show that the duration of both the intake and exhaust camshafts significantly impacts the ability to achieve high load operation. While it was noted that the flow through the exhaust valve chokes for the majority of the exhaust stroke for peak exhaust lifts less than 8 mm, the engine rating could be achieved with peak intake lifts as low as 4 mm. Therefore, camshafts with peak lifts of 8/4 mm exhaust/intake were down selected to facilitate multimode combustion operation with high levels of PVO. Analysis of high load operation with the down-selected camshafts indicates that peak unburned gas temperatures remain low enough to mitigate end-gas knock, while other variables such as peak cylinder pressure, turbine inlet temperature and turbocharger speed are all predicted to be within acceptable limits.
RCCI Operation With PFI of n-Butanol and DI of Biodiesel Compared With DI of Binary Mixtures of n-Butanol and Biodiesel
Authors: Soloiu Valentin , Duggan Marvin , Weaver Jabeous , Vlcek Brian , Harp Spencer , Molina Gustavo 
Published: February 2014

In this study the Reactive Controlled Combustion Ignition (RCCI) obtained by early port fuel injection (PFI) of n-butanol and direct injection (DI) of biodiesel were compared with in cylinder direct injected binary mixture of n-butanol and biodiesel with the same mass ratio of 3:1 in both fuelling strategies. The combustion and emissions characteristics were investigated at 5 bars IMEP at 1400 rpm. The ignition for DI of n-butanol-biodiesel binary blends showed a delay by approximately 7.5°CAD compared with the PFI case. For the binary mixture, n-butanol-biodiesel, the combustion pressure has decreased by 50% compared to the PFI of butanol. The maximum in cylinder gas temperature decreased by 100K for the n-butanol-biodiesel mixture versus ULSD#2 and has also experienced a 10° CAD delay. The premixed charge combustion has been split into two regions of high temperature heat release, an early one BTDC, and a second stage, ATDC for the PFI strategy. Increasing the load to 7.5 bars IMEP, heavy knock occurred for the PFI case. The soot emissions showed a 90% decrease with n-butanol injection PFI and by 98% reduction for DI of n-butanol binary mixture with the biodiesel, while the NOx emissions were reduced by 40% in both cases. The aldehyde emissions exhibited a significant 95% decrease for the n-butanol-biodiesel binary mixture compared with the n-butanol PFI. The mechanical efficiency at 80% and thermal efficiency and 38% were found similar, for both fuelling strategies.
The results of this work suggest that the DI of n-butanol-biodiesel binary mixtures is more effective in reducing emissions than PFI of n-butanol combined with DI of biodiesel and also less likely to produce knock.
Women Outperform Men in Ultradistance Swimming: The Manhattan Island Marathon Swim from 1983 to 2013
Authors: Knechtle Beat , Rosemann Thomas , Lepers Romuald , Rüst Christoph Alexander 
Published: February 2014

Purpose:Recent studies suggested that women’s and men’s ultraswim performances may be similar for distances of ~35 km. The current study investigated both the gender difference and the age of peak ultraswim performance between 1983 and 2013 at the 46-km Manhattan Island Marathon Swim with water temperatures <20°C.Methods:Changes in race times and gender difference in 551 male and 237 female finishers were investigated using linear-, nonlinear-, and hierarchical multilevel-regression analyses.Results:The top 10 race times ever were significantly (P < .0001) lower for women (371 ± 11 min) than for men (424 ± 9 min). Race times of the annual fastest and annual 3 fastest women and men did not differ between genders and remained stable across years. The age of the annual 3 fastest swimmers increased from 28 ± 4 y (1983) to 38 ± 6 y (2013; r2 = .06, P = .03) in women and from 23 ± 4 y (1984) to 42 ± 8 y (2013; r2 = .19, P < .0001) in men.Conclusions:The best women were ~12–14% faster than the best men in a 46-km open-water ultradistance race with temperatures <20°C. The maturity of ultradistance swimmers has changed during the last decades, with the fastest swimmers becoming older across the years.
Functional Analysis Using Whole-Genome Sequencing of a Drug-Sensitive Mycobacterium tuberculosis Strain from Peru
Authors: Tarazona D. , Borda V. , Galarza M. , Agapito J. C. , Guio H. 
Published: February 2014

ABSTRACT

We report the whole-genome sequence of a Latin American-Mediterranean (LAM) lineage drug-sensitive
Mycobacterium tuberculosis
strain from Peru, INS-SEN. The functional analysis revealed more mutations in secondary metabolite biosynthesis, transport, and catabolism (clusters of orthologous groups [COG] category Q) than for other LAM-sensitive strains. This study contributes to the understanding of the genomic diversity of drug-sensitive
M. tuberculosis
.
Insight into the Draft Genome Sequence of Human Isolate Lactobacillus rhamnosus LR231, a Bacterium with Probiotic Potential
Authors: Ambalam Padma , Pithva Sheetal , Kothari Charmy , Kothari Ramesh , Parmar Nidhi , Nathani Neelam M. , Koringa Prakash G. , Joshi Chaitanya G. , Dave J. M. , Vyas B. R. M. 
Published: February 2014

ABSTRACT

Lactobacillus rhamnosus
strain LR231 was isolated from the feces of healthy human subjects. It is observed to be a potential probiotic strain, having a broad spectrum of antimicrobial activity against a wide range of human pathogens and food pathogens. Here, we provide the 2.59-Mb draft genome sequence of
L. rhamnosus
LR231.
Genetic polymorphism ofNFKB1andNFKBIAgenes and liver cancer risk: a nested case–control study in Shanghai, China
Authors: Gao Jing , Xu Hong-Li , Gao Shan , Zhang Wei , Tan Yu-Ting , Rothman Nat , Purdue Mark , Gao Yu-Tang , Zheng Wei , Shu Xiao-Ou , Xiang Yong-Bing 
Published: February 2014

ObjectivesGenetic variations of nuclear factor-κB (NF-κB) signalling pathway were found to be associated with inflammatory diseases and several malignancies. However, little is known about NF-κB pathway gene polymorphisms and susceptibility of liver cancer. The aim of this study was to investigate whether genetic variants ofNFKB1andNFKBIAwere associated with risk of liver cancer in a Chinese population.DesignThe study was designed as a nested case–control study within two prospective cohorts (the Shanghai Women's Health Study, SWHS, 1996–2000 and the Shanghai Men's Health Study, SMHS, 2002–2006).SettingsThis population-based study was conducted in urban Shanghai, China.ParticipantsA total of 217 incident liver cancer cases diagnosed through 31 December 2009 and 427 healthy controls matched by sex, age at baseline (±2 years) and date (±30 days) of sample collection were included in the study.Primary and secondary outcome measuresGenetic polymorphisms ofNFKB1andNFKBIAwere determined blindly by TaqMan single-nucleotide polymorphism (SNP) genotyping assay. OR and its 95% CIs were estimated by an unconditional logistic regression model to measure the association between selected SNPs and the risk of liver cancer.ResultsAfter adjusted for potential confounding factors, rs28362491 ins/del or del/del genotypes were associated with higher risk of liver cancer with an adjusted OR 1.54 (95% CI 1.04 to 2.28). rs230496 AG and GG genotypes were also noted with higher risk of liver cancer with an adjusted OR 1.53 (95% CI 1.03 to 2.26). Haplotype analysis indicated that carriers of theNFKB1GA and AA (rs230525-rs230530) haplotypes had higher risk of liver cancer under an additive model. No association was observed betweenNFKBIAvariants and risk of live cancer.ConclusionsOur results suggest that genetic variants ofNFKB1influence liver cancer susceptibility in Chinese population, although replication in other studies is needed.