bluuebunny/crossref_metadata_2025_split huggingface dataset:
Particulate Matter Emission Comparison of Spark Ignition Direct Injection (SIDI) and Port Fuel Injection (PFI) Operation of a Boosted Gasoline Engine
Authors: Su Jianye , Lin Weiyang , Sterniak Jeff , Xu Min , Bohac Stanislav V. 
Published: February 2014

Spark ignition direct injection (SIDI) gasoline engines, especially in downsized boosted engine platforms, are increasing their market share relative to port fuel injection (PFI) engines in U.S., European and Chinese vehicles due to better fuel economy by enabling higher compression ratios and higher specific power output. However, particulate matter (PM) emissions from engines are becoming a concern due to adverse human health and environment effects, and more stringent emission standards. To conduct a PM number and size comparison between SIDI and PFI systems, a 2.0 L boosted gasoline engine has been equipped and tested with both systems at different loads, air fuel ratios, spark timings, fuel pressures and injection timings for SIDI operation and loads, air fuel ratios and spark timings for PFI operation.
Regardless of load, air fuel ratio, spark timing, fuel pressure, and injection timing, particle size distribution from SIDI and PFI is shown to be bimodal, exhibiting nucleation and accumulation mode particles. SIDI produces particle numbers that are an order of magnitude greater than PFI. Particle number can be reduced by retarding spark timing and operating the engine lean, both for SIDI and PFI operation. Increasing fuel injection pressure and optimizing injection timing with SIDI also reduces PM emissions. This study provides insight into the differences in PM emissions from boosted SIDI and PFI engines and an evaluation of PM reduction potential by varying engine operating parameters in boosted SIDI and PFI gasoline engines.
Lower Compression Ring and Oil Control Ring Changes for Modern Diesel Engines
Authors: Bieneman Jason 
Published: February 2014

The operating environment for piston rings in modern diesel engines continues to become more severe. Engine manufacturers are not only making changes to the engine to meet the government mandated emissions standards, but at the same time they are increasing both engine efficiencies and specific power levels. In order to meet these performance demands, Peak Cylinder Pressures (PCP) are increasing and piston compression heights are being reduced. These changes require significant upgrades to the Power Cylinder Unit (PCU), including piston and piston ring pack, as historic solutions no longer provide the robustness required for the next generation high output diesel engines.
Much attention has already been paid to improving top compression ring technology [1]. This paper will instead focus on how the lower compression ring and oil control ring are impacted by these increasing demands; as well as how design changes to these rings can help the engine manufacturers meet their performance goals. Changes to ring base material, ring face coatings, and running surface geometries will be explained along with a brief discussion about the influence of the ring’s boundary conditions and the changes that are simultaneously being made to surrounding components. These recommendations will be supported with bench test, simulations using the MIT ring pack code [2], and engine test results using numerous MDD/HDD engines.
Study of Performance Characteristics of Opposed-Piston Folded-Cranktrain Engines
Authors: Zhao Zhenfeng , Zhang Fujun , Huang Ying , Zhang Zhenyu , Wu Dan 
Published: February 2014

This paper discusses a prototype of horizontally opposed-piston folded-cranktrain two-stroke diesel engine with combined supercharger and high-pressure common rail fuel system by Beijing Institute of Technology. The cranktrain dynamics, the thermodynamics (include the combustion process and the scavenging) are investigated, which is the main difference between this type of engine and conventional engines. The aim of the work is to design and develop a prototype of opposed-piston folded-cranktrain engine. The investigated results showed that maximum speeds of two pistons are all 13.99m/s, while the mean velocity is 9.4 m/s; the maximum acceleration on negative side is 3765 m/s2 when the piston is near the BDC and the maximum acceleration on positive side is 2944 m/s2 when the pistons is near the TDC; scavenging efficiency can get to 89% and the final air utilization is 55%.
The prototype of opposed-piston folded-cranktrain engine has been developed.
Comparison of 1-D vs 3-D Combustion Boundary Conditions for SI Engine Thermal Load Prediction
Authors: Iqbal O. , Jonnalagedda S. , Arora K. , Zhong L. , Gaikwad S. 
Published: February 2014

The thermal field generated in an engine block and cylinder head as a result of combustion loading is of paramount significance for structural durability. Computational fluid dynamics and heat transfer modeling provide strong tools; perhaps the best and most precise available for predicting thermal fields within cylinder head and engine block. However, an enduring challenge has been the temperature prediction on metal wall as a response to the time dependent fluctuations in the fluids. Fluid (coolant) flow in an engine is steady for a given engine speed and load, but combustion dynamics are inherently transient. In this study, an effective set of convective boundary condition data (as combustion load) is generated using two different approaches in a stand-alone simulation and mapped onto a decoupled Conjugate Heat Transfer (CHT) model to predict the temperature distribution in the engine.
In the first approach, a predictive combustion model, tuned to dyno test data, is solved in a 1-D simulation code. This provides the cycle-averaged convective boundary condition that can be used for a CHT model as a uniform heat source. In the second, more detailed approach, in-cylinder combustion simulations involving transient piston and valve motion with flame propagation modeling are carried out using a 3-D simulation code. The 3-D methodology gives a detailed distribution of convective boundary conditions on the walls touching the combustion gases. In order to predict the gradients in heat transfer coefficient with high accuracy, the resulting temperature distribution from the CHT simulation is fed back into the combustion model to regenerate the set of convective boundary conditions. This process is repeated until a converged set of convective boundary conditions are obtained.
In this paper engine temperature predictions obtained using combustion loads from both 1-D and 3-D approaches will be compared with the thermocouple data from engine dyno test.
Simulation of n-Heptane and Surrogate Fuels for Advanced Combustion Engines (FACE) in a Single-Cylinder Compression Ignition Engine
Authors: Taglialegami Joseph , Bogin Gregory , Osecky Eric , Dean Anthony M. 
Published: February 2014

A CFD model of a HATZ diesel engine was developed for the purpose of simulating low temperature combustion (LTC) of surrogate diesel fuels for the Fuels for Advanced Combustion Engines (FACE). Initial validation of the model was performed using n-heptane data from a single cylinder HATZ diesel engine. Simulations were run with both a detailed n-heptane mechanism and several reduced mechanisms to determine the suitability of using a reduced mechanism to capture the main ignition characteristics and emissions. It was found that a 173 species n-heptane mechanism predicts start of combustion (SOC) within 0.5 crank angle degrees of the detailed 561 species mechanism. The 173 species mechanism required 27 hours of computational time to reach the end of the simulation whereas the 561 species detailed mechanism required 41 hours under the same conditions. Two additional reduced mechanisms, containing 85 and 35 species, were provided reasonable accuracy with a computational time of 8 hours and 2 hours, respectively. Due to the varying physical and chemical properties of the FACE surrogates, a sensitivity analysis of the effects of the physical properties was conducted by changing the n-heptane physical properties to those of n-hexadecane while keeping the chemistry the same. As expected, when the fuel properties of n-hexadecane (which is less volatile than n-heptane) were used with the n-heptane kinetics, SOC was delayed and the net heat release rate was reduced.
The FACE fuels were developed to fulfill the need for research grade fuels that are able to represent common refinery stream fuels. Since the FACE fuels consist of hundreds of fuel components, it is not feasible to model the actual FACE fuels in a full-scale engine model. An alternative is to develop surrogates consisting of relatively few species for which detailed mechanisms are available. Even then this mechanism would need to be reduced to make the computation practical. For this work, a detailed diesel surrogate mechanism was reduced from 4016 species to 1046 species to match the characteristics for FACE fuels 1, 3, 5, 8, and 9. The surrogates only contain 4–7 species. Using the single chemical mechanism to represent five surrogate FACE fuels, it was found that ∼200°C of air preheat was required to achieve autoignition in the HATZ model compared to the 130°C of air preheat required experimentally. Initial runs have found that there were similar trends in SOC and heat release between the FACE fuel surrogate experiments and simulations for the respective fuels. Future work will require improvements on the single chemical mechanism to represent the five surrogate FACE fuels.
Mammographic quantitative image analysis and biologic image composition for breast lesion characterization and classification
Authors: Drukker Karen , Duewer Fred , Giger Maryellen L. , Malkov Serghei , Flowers Chris I. , Joe Bonnie , Kerlikowske Karla , Drukteinis Jennifer S. , Li Hui , Shepherd John A. 
Published: February 2014

Purpose:To investigate whether biologic image composition of mammographic lesions can improve upon existing mammographic quantitative image analysis (QIA) in estimating the probability of malignancy.Methods:The study population consisted of 45 breast lesions imaged with dual‐energy mammography prior to breast biopsy with final diagnosis resulting in 10 invasive ductal carcinomas, 5 ductal carcinomain situ, 11 fibroadenomas, and 19 other benign diagnoses. Analysis was threefold: (1) The raw low‐energy mammographic images were analyzed with an established in‐house QIA method, “QIA alone,” (2) the three‐compartment breast (3CB) composition measure—derived from the dual‐energy mammography—of water, lipid, and protein thickness were assessed, “3CB alone”, and (3) information from QIA and 3CB was combined, “QIA + 3CB.” Analysis was initiated from radiologist‐indicated lesion centers and was otherwise fully automated. Steps of the QIA and 3CB methods were lesion segmentation, characterization, and subsequent classification for malignancy in leave‐one‐case‐out cross‐validation. Performance assessment included box plots, Bland–Altman plots, and Receiver Operating Characteristic (ROC) analysis.Results:The area under the ROC curve (AUC) for distinguishing between benign and malignant lesions (invasive and DCIS) was 0.81 (standard error 0.07) for the “QIA alone” method, 0.72 (0.07) for “3CB alone” method, and 0.86 (0.04) for “QIA+3CB” combined. The difference in AUC was 0.043 between “QIA + 3CB” and “QIA alone” but failed to reach statistical significance (95% confidence interval [–0.17 to + 0.26]).Conclusions:In this pilot study analyzing the new 3CB imaging modality, knowledge of the composition of breast lesions and their periphery appeared additive in combination with existing mammographic QIA methods for the distinction between different benign and malignant lesion types.
Efficacy of fixed filtration for rapid kVp‐switching dual energy x‐ray systems
Authors: Yao Yuan , Wang Adam S. , Pelc Norbert J. 
Published: February 2014

Purpose:Dose efficiency of dual kVp imaging can be improved if the two beams are filtered to remove photons in the common part of their spectra, thereby increasing spectral separation. While there are a number of advantages to rapid kVp‐switching for dual energy, it may not be feasible to have two different filters for the two spectra. Therefore, the authors are interested in whether a fixed added filter can improve the dose efficiency of kVp‐switching dual energy x‐ray systems.Methods:The authors hypothesized that a K‐edge filter would provide the energy selectivity needed to remove overlap of the spectra and hence increase the precision of material separation at constant dose. Preliminary simulations were done using calcium and water basis materials and 80 and 140 kVp x‐ray spectra. Precision of the decomposition was evaluated based on the propagation of the Poisson noise through the decomposition function. Considering availability and cost, the authors chose a commercial Gd2O2S screen as the filter for their experimental validation. Experiments were conducted on a table‐top system using a phantom with various thicknesses of acrylic and copper and 70 and 125 kVp x‐ray spectra. The authors kept the phantom exposure roughly constant with and without filtration by adjusting the tube current. The filtered and unfiltered raw data of both low and high energy were decomposed into basis material and the variance of the decomposition for each thickness pair was calculated. To evaluate the filtration performance, the authors measured the ratio of material decomposition variance with and without filtration.Results:Simulation results show that the ideal filter material depends on the object composition and thickness, and ranges across the lanthanide series, with higher atomic number filters being preferred for more attenuating objects. Variance reduction increases with filter thickness, and substantial reductions (40%) can be achieved with a 2× loss in intensity. The authors’ experimental results validate the simulations, yet were overall slightly worse than expectation. For large objects, conventional (non‐K‐edge) beam hardening filters perform well.Conclusions:This study demonstrates the potential of fixed K‐edge filtration to improve the dose efficiency and material decomposition precision for rapid kVp‐switching dual energy systems.
Combining Internal- and External-Training-Load Measures in Professional Rugby League
Authors: Weaving Dan , Marshall Phil , Earle Keith , Nevill Alan , Abt Grant 
Published: February 2014

Purpose:This study investigated the effect of training mode on the relationships between measures of training load in professional rugby league players.Methods:Five measures of training load (internal: individualized training impulse, session rating of perceived exertion; external—body load, high-speed distance, total impacts) were collected from 17 professional male rugby league players over the course of two 12-wk preseason periods. Training was categorized by mode (small-sided games, conditioning, skills, speed, strongman, and wrestle) and subsequently subjected to a principal-component analysis. Extraction criteria were set at an eigenvalue of greater than 1. Modes that extracted more than 1 principal component were subjected to a varimax rotation.Results:Small-sided games and conditioning extracted 1 principal component, explaining 68% and 52% of the variance, respectively. Skills, wrestle, strongman, and speed extracted 2 principal components each explaining 68%, 71%, 72%, and 67% of the variance, respectively.Conclusions:In certain training modes the inclusion of both internal and external training-load measures explained a greater proportion of the variance than any 1 individual measure. This would suggest that in training modes where 2 principal components were identified, the use of only a single internal or external training-load measure could potentially lead to an underestimation of the training dose. Consequently, a combination of internal- and external-load measures is required during certain training modes.
Six Weeks of Unsupervised Nintendo Wii Fit Gaming Is Effective at Improving Balance in Independent Older Adults
Authors: Nicholson Vaughan Patrick , McKean Mark , Lowe John , Fawcett Christine , Burkett Brendan 
Published: February 2014

Objective:To determine the effectiveness of unsupervised Nintendo Wii Fit balance training in older adults.Methods:Forty-one older adults were recruited from local retirement villages and educational settings to participate in a six-week two-group repeated measures study. The Wii group (n = 19, 75 ± 6 years) undertook 30 min of unsupervised Wii balance gaming three times per week in their retirement village while the comparison group (n = 22, 74 ± 5 years) continued with their usual exercise program. Participants’ balance abilities were assessed pre- and postintervention.Results:The Wii Fit group demonstrated significant improvements (P < .05) in timed up-and-go, left single-leg balance, lateral reach (left and right), and gait speed compared with the comparison group. Reported levels of enjoyment following game play increased during the study.Conclusion:Six weeks of unsupervised Wii balance training is an effective modality for improving balance in independent older adults.
On-Field Signs and Symptoms Associated With Recovery Duration After Concussion in High School and College Athletes: A Critically Appraised Topic
Authors: Shim Jaebin , Smith Deanna H. , Van Lunen Bonnie L. 
Published: February 2014

Clinical Scenario:Over the past decade, sport-related concussions have received increased attention due to their frequency and severity over a wide range of athletics. Clinicians have developed return-to-play protocols to better manage concussions in young athletes; however, a standardized process projecting the length of recovery time after concussion has remained an elusive piece of the puzzle. The recovery times associated with such an injury once diagnosed can last anywhere from 1 wk to several months. Risk factors that could lead to protracted recovery times include a history of 1 or multiple concussions and a greater number, severity, and duration of symptoms after the injury. Examining the possible relationship between on-field or sideline signs and symptoms and recovery times would give clinicians the confident ability to properly treat and manage an athlete’s recovery process in a more systematic manner. Furthermore, identifying factors after a head injury that may be predictive of protracted recovery times would be useful for athletes, parents, and coaches alike.Focused Clinical Question:Which on-field and sideline signs and symptoms affect length of recovery after concussion in high school and college athletes?
Draft Genome Sequence of
Pedobacter
sp. Strain V48, Isolated from a Coastal Sand Dune in the Netherlands
Authors: Bitzer Adam S. , Garbeva Paolina , Silby Mark W. 
Published: February 2014

ABSTRACT

Pedobacter
sp. strain V48 participates in an interaction with
Pseudomonas fluorescens
which elicits interaction-induced phenotypes. We report the draft genome sequence of
Pedobacter
sp. V48, consisting of 6.46 Mbp. The sequence will contribute to improved understanding of the genus and facilitate genomic analysis of the model interspecies interaction with
P. fluorescens
.
Whole-Genome Sequence of Muju Virus, an Arvicolid Rodent-Borne Hantavirus
Authors: Lee Jin Goo , Gu Se Hun , Baek Luck Ju , Shin Ok Sarah , Kim Heung-Chul , Klein Terry A. , Yanagihara Richard , Song Jin-Won 
Published: February 2014

ABSTRACT

The complete genome sequence of Muju virus was determined from lung tissue samples of three royal voles (
Myodes regulus
) captured in Gangwon province in the Republic of Korea. Since few whole genome sequences of hantaviruses are available, this sequence may help to clarify the molecular phylogeny of arvicolid rodent-borne hantaviruses.
Prevalence and trend of dyslipidaemia from 1996 to 2006 among normal and overweight adolescents in Taiwan
Authors: Kuo Philip , Syu Jhu-Ting , Tzou Isabel Lin , Chen Pi-Yun , Su Hsiu-Yueh , Chu Nain-Feng 
Published: February 2014

ObjectivesTo evaluate the trend of dyslipidaemia from 1996 to 2006 and examine its relationship with weight status among adolescents in Taiwan.Design2 cross-sectional surveys were conducted in 1996 and 2006.SettingThe junior high schools in Taipei.ParticipantsAfter multistage sampling, total of 1500 and 1283 junior high school students were chosen in 1996 and 2006. After excluding missing data, a total of 1353 (676 boys and 677 girls) and 1203 (585 boys and 618 girls) children were included in the final analyses in 1996 and 2006.Outcome measuresAnthropometric measures as body height and weight were measured, and body mass index (BMI) was calculated. Blood lipid profiles as total cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol were measured.ResultsFrom 1996 to 2006, the prevalence of dyslipidaemia and hypercholesterolaemia significantly increased from 13% (95% CI 11.3% to 15.0%) to 22.3% (95% CI 20.0% to 24.7%) and 6.2% (95% CI 5.0% to 7.6%) to 13.8% (95% CI 11.9% to 15.9%), respectively. The prevalence of hypertriglyceridaemia and low HDL-C dyslipidaemia increased from 3% (95% CI 1.8% to 4.5%) to 4.3% (95% CI 2.8% to 6.2%) and 6.5% (95% CI 4.8% to 8.6%) to 11.6% (95% CI 9.1% to 14.5%), with significance seen only in boys. When compared with normal weight participants, overweight boys and girls faced a 2-fold and 1.6-fold increased risk of dyslipidaemia, respectively, in the 2006 study. The increased risk of low HDL-C dyslipidaemia for overweight participants was 2.6-fold and 7.2-fold in boys and girls, respectively. In 2006, each unit increment of BMI was associated with 28%, 13% and 13% risk of hypertriglyceridaemia, low HDL-C and dyslipidaemia for boys, and 25% risk of low HDL-C dyslipidaemia in girls.ConclusionsThe prevalence of dyslipidaemia had increased significantly for boys and girls in normal weight and overweight adolescents. Early screening of dyslipidaemia and weight intervention programmes in adolescents will be the key to prevent dyslipidaemia and cardiovascular-related comorbidities.
Warfarin treatment among Finnish patients with atrial fibrillation: retrospective registry study based on primary healthcare data
Authors: Hallinen Taru , Soini Erkki J , Asseburg Christian , Kuosmanen Pekka , Laakkonen Ari 
Published: February 2014

ObjectiveTo assess the frequency of warfarin use, the achieved international normalised ratio (INR) balance among warfarin users and the primary healthcare outpatient costs of patients with atrial fibrillation (AF).DesignRetrospective, non-interventional registry study.SettingPrimary healthcare.ParticipantsAll patients with AF (n=2746) treated in one Finnish health centre between October 2010 and March 2012.MethodsData on healthcare resource use, warfarin use, individually defined target INR range and INR test results were collected from the primary healthcare database for patients with AF diagnosis. The analysed dataset consisted of a 1-year follow-up. Warfarin treatment balance was estimated with the proportion of time spent in the therapeutic INR range (TTR). The cost of used healthcare resources was valued separately with national and service provider unit costs to estimate the total outpatient treatment costs. The factors potentially impacting the treatment costs were assessed with a generalised linear regression model.ResultsApproximately 50% of the patients with AF with CHADS-VASc ≥1 used warfarin. The average TTR was 65.2% but increased to 74.5% among patients using warfarin continuously (ie, without gaps exceeding 56 days between successive INR tests) during follow-up. One-third of the patients had a TTR of below 60%. The average outpatient costs in the patient cohort were €314.44 with the national unit costs and €560.26 with the service provider unit costs. The costs among warfarin users were, on average, €524.11 or €939.54 higher compared with the costs among non-users, depending on the used unit costs. A higher TTR was associated with lower outpatient costs.ConclusionsThe patients in the study centre using warfarin were, on average, well controlled on warfarin, yet one-third of patients had a TTR of below 60%.