bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of Combustion Phasing Control Strategy During Reactivity Controlled Compression Ignition (RCCI) Multi-Cylinder Engine Load Transitions
Authors: Wu Yifeng , Hanson Reed , Reitz Rolf D. 
Published: February 2014

The dual fuel reactivity controlled compression ignition (RCCI) concept has been successfully demonstrated to be a promising, more controllable, high efficiency and cleaner combustion mode. A multi-dimensional computational fluid dynamics (CFD) code coupled with detailed chemistry, KIVA-CHEMKIN, was applied to develop a strategy for phasing control during load transitions. Steady-state operating points at 1500 rev/min were calibrated from 0 to 5 bar brake mean effective pressure (BMEP). The load transitions considered in this study included a load-up and a load-down load change transient between 1 bar and 4 bar BMEP at 1500 rev/min. The experimental results showed that during the load transitions, the diesel injection timing responded in 2 cycles while around 5 cycles were needed for the diesel common-rail pressure to reach the target value. However, the intake manifold pressure lagged behind the pedal change for about 50 cycles due to the slower response of the turbocharger.
The effect of these transients on RCCI engine combustion phasing was studied. The CFD model was first validated against steady-state experimental data at 1 bar and 4 bar BMEP. Then the model was used to develop strategies for phasing control by changing the direct port fuel injection (PFI) amount during load transitions. Specific engine operating cycles during the load transitions (6 cycles for the load-up transition and 7 cycles for the load-down transition) were selected based on the change of intake manifold pressure to represent the transition processes. Each cycle was studied separately to find the correct PFI to diesel fuel ratio for the desired CA50 (the crank angle at which 50 % of total heat release occurs). The simulation results showed that CA50 was delayed by 7 to 15 degrees for the load-up transition and advanced by around 5 degrees during the load-down transition if the pre-calibrated steady-state PFI table was used. By decreasing the PFI ratio by 10 % to 15 % during the load-up transition and increasing the PFI ratio by around 40 % during the load-down transition, the CA50 could be controlled at a reasonable value during transitions. The control strategy can be used for closed-loop control during engine transient operating conditions. Combustion and emission results during load transitions are also discussed.
Development of Radio Frequency Sensing for In-Situ Diesel Particulate Filter State Monitoring and Aftertreatment System Control
Authors: Sappok Alexander , Bromberg Leslie 
Published: February 2014

Diesel particulate filters (DPF) have seen widespread application in the United States and Europe to meet stringent diesel particulate matter (PM) emissions regulations. Now commonplace on most on-road diesel vehicles, DPFs are being increasingly applied to diesel-powered off-road equipment as additional regulations are phased in. Further, recent awareness of particulate matter emissions from gasoline direct injection engines has motivated additional study into potential applications of gasoline particulate filters (GPF).
Key to the efficient operation of the combined engine and emissions aftertreatment system, is the accurate determination of the filter loading state, to enable precise control of filter regeneration and on-board diagnostics. Currently pressure- and model-based controls are utilized, in parallel, to provide an indirect estimate of filter loading. This work presents results of an investigation applying radio frequencies (RF) to monitor the accumulation of particulate matter in the DPF, providing a direct, in-situ determination of filter loading state. Simulation results, supported by experimental measurements, are provided to demonstrate the utility of the technique to monitor not only the filter loading state but also to provide a measure of the spatial distribution of the accumulated material. The results of this work indicate significant potential to apply RF-based sensing for improved monitoring and control of the particulate filter in a range of applications.
Improvement of a Diesel Engine Water Cooling Performance Through Implementation of Different Cooling Designs
Authors: Jafarabadi Mazdak , Chamani Hamidreza , Jazayeri Seyed Ali 
Published: February 2014

Improving engine cooling performance requires sophisticated and intelligent engine cooling design especially when interactions of all engine parts are to be considered. The cooling system would highly influence engine thermal efficiency, durability and engine design criteria. Several attempts have been made by engine designers to improve the cooling design during the past decades, each with particular purpose considerations.
In this paper, based on the cylinder head flame face of an existing heavy duty medium speed diesel engine, three other flame face cooling systems are designed, modeled and changes are implemented using a three dimensional computer aided design modeling software. Modeled cylinder head flame face cooling concepts are experiencing the effect of cooling passages geometry changes on performance of thermal efficiency, effective subcooled regions and other resultant factors.
A detailed coupled computational fluid dynamic and thermal finite element analysis for one cylinder bank assembly is performed several times; paying special attention to the risky areas to get comparative results to assess the flame face cooling designs. Engine specifications and loading conditions together with the engine performance data are available from test rig. Initial and boundary conditions have been determined through a global model simulation and analysis.
The subcooled nucleate boiling heat transfer computation is carried out using the boiling departure lift-off model. In order to obtain the temperature for components under consideration, a comprehensive thermal analysis has been performed coupling with the detailed CFD analysis to reach an accepted value through transferring data between the CFD and FEA software. This method leads to an accurate prediction of the wall temperature and heat flux.
It is observed that proper cooling design could improve wall temperature and thermal stress related phenomena significantly. The advantages and disadvantages of each concept are discussed and preferred flame face design is demonstrated. Calculated results of original design are validated with test cell records.
Thermodynamic Modeling of an Epitrochoidal Engine Cycle
Authors: Grammer Thomas Allen , Bittle Robert R. 
Published: February 2014

A thermodynamic performance model has been developed for a new four-stroke piston engine design in which the crankshaft path is epitrochoidal, or non-circular. The model is based on an Otto air-standard cycle with non-ideal effects of friction, valve and spark timing, heat transfer, volumetric efficiency, and fuel burn timing then added. The same modeling approach was then used in developing a standard circular path engine model for comparison: the result being two discrete models varying only in their crankshaft paths, and thus piston path timing.
The thermodynamic modeling was one phase of a larger senior design project in which senior engineering students were tasked with answering the question of whether the epitrochoidal crankshaft path engine will produce more power than a standard circular path engine of the same size and compression ratio. The starting point for the effort was the epitrochoidal crankshaft design description given in the patent, followed by major challenges of design, fabrication, modeling, and testing of a prototype engine. A Briggs and Stratton model 20 was employed as the standard circular crankshaft path comparison engine, and upon which the epitrochoidal prototype engine geometry was based. The result was two test engines of the same size and compression ratio, but differing in crankshaft path. Thermodynamic modeling, however, is the primary focus of the paper presented herein. Details of the design/fabrication/testing phases of the larger project are included in another paper, currently in preparation.
The modeling description starts with the development of the mathematical equations describing the piston movement within the standard engine and the epitrochoidal engine, followed by the specifics of the thermodynamic modeling and inclusion of non-ideal effects. The model calibration to measured data is developed next, and finally a prediction of the epitrochoidal engine performance is shown to agree with measured data for the prototype engine. The testing did in fact show an increase in power in the epitrochoidal prototype engine, and the modeling was used to explain the improvements attributable to the epitrochoidal design. These results also affirmed the comparative modeling approach that was used.
Analyses for Lateral Deflection of Railroad Track Under Quasi-Static Loading
Authors: Jeong David Y. 
Published: February 2014

This paper describes analyses to examine the lateral deflection of railroad track subjected to quasi-static loading. Rails are assumed to behave as beams in bending. Movement of the track in the lateral plane is constrained by idealized resistance characteristics, while movement in the vertical plane is resisted by a continuous, linear and elastic foundation. These analyses are based on solving the ordinary differential equations for beam deflections. In certain cases, convenient mathematical expressions may be used to represent idealized lateral resistance characteristics and derive closed-form equations to relate lateral force as a function of track lateral deflection. However, in general, the idealized lateral resistance characteristic may be nonlinear, in which case numerical methods are required to examine the lateral load versus track lateral deflection behavior. In these general cases, a Fourier series technique is used to solve the governing equations numerically.
The analysis of track lateral deflection subjected to quasi-static loads may be applied to examine track shift. For example, lateral resistance of track may be measured using Track Lateral Pull Tests (TLPT). The Fourier method is also used to examine the relationship between lateral and vertical wheel loads and track lateral shift.
Insulated Railroad Joint Design Evaluation by Coordinated Test and Finite Element Analysis
Authors: Iranmanesh Amir H. , West Robert L. , Ahmadian Mehdi 
Published: February 2014

The railroad industry faces challenges with bonded insulated joint designs in the present practice. A program initiated by Virginia Tech and the Transportation Technology Center Incorporated (TTCI) has been in progress to analyze and test a class of insulated joint designs featuring non-adhesive bolted connections. A hierarchical approach to finite element modeling with a parametric model maintaining essential mechanics of the joints has been applied to develop a bolted insulated joint design.
The current paper reports on the recent phase of the program including development of experimental tests along with finite element analyses on scaled simplified insulated rail joint models. Two baseline rail joint configurations with simplified sections were considered for studying dominant mechanics under the AREMA (American Railway Engineering and Maintenance-of-Way Association) rail joint acceptance standard test loading and boundary conditions. The finite element models developed based on three-dimensional continuum elements incorporated bolt preloads and full-contact analysis. In the experimental tests, the strain analyses on 1/4 scaled polycarbonate rail joint specimens were performed by means of an array of strain gauge transducers mounted on the joint bars and a photoelasticity technique. The results of the experimental stress analyses were employed to validate the finite element models quantitatively and qualitatively in terms of load transfer mechanics and stress distribution.
The validated models serve as baseline insulated joint configurations for developing fracture-mechanics-based fatigue-failure analysis. To investigate the role of cracks on the performance and reliability of joint bars, a damage tolerant analysis is performed on the rail joints utilizing linear elastic fracture mechanics. The locations of most critical type defects are estimated based on high stress/strain regions from stress analyses along with past experiences on failure of rail joints. To characterize the severity of theses defects under alternating loading conditions, stress intensity factors are computed as a function of crack length. Cracks of different lengths are introduced in the vicinity of the most fatigue-prone locations of the joint bar in a parametric modeling fashion. The fatigue-crack-growth-rate properties in terms of Paris Law scaling constants are selected from a survey of available material data. The number of loading cycles to failure is obtained by employing the computed stress-intensity factors as well as initial and final crack sizes. Predicted lifetimes as a function of pre-existing crack sizes and geometry of joint configuration can be used as a fracture-mechanics-based function for more accurate design of the rail joints.
Transfer Bond Test Used to Predict Transfer Length of Concrete Railroad Ties
Authors: Holste Joseph R. , Peterman Robert J. , Bodapati Naga Narendra B. , Beck B. Terry , Wu Chih-Hang John 
Published: February 2014

A study was conducted at Kansas State University to determine the correlation between tensioned-wire pullout tests and the corresponding transfer lengths in prestressed concrete railroad ties. Five different 5.32-mm-diameter pre-stressing wires were selected to be used on this project based on previous testing conducted at Kansas State University (KSU). The wires were tested to simulate the transfer-length bond.
The transfer-length bond test involved tensioning each of the wires to 75% of their ultimate capacity, casting concrete around each wire and then de-tensioning the wire when the concrete had reached 4,500 psi. End-slip and force measurements were recorded on both sides of the specimen as the wire was de-tensioned.
Transfer bond data was used to investigate the transfer length that each wire type would expect to see in a concrete railroad tie. Prisms with each wire type were cast and the transfer length was measured for each type of wire. Prism measurements were used along with the transfer bond data to correlate a relation between the transfer bond test and the transfer lengths of the prisms.
Predicting error in detecting mammographic masses among radiology trainees using statistical models based on BI‐RADS features
Authors: Grimm Lars J. , Ghate Sujata V. , Yoon Sora C. , Kuzmiak Cherie M. , Kim Connie , Mazurowski Maciej A. 
Published: February 2014

Purpose:The purpose of this study is to explore Breast Imaging‐Reporting and Data System (BI‐RADS) features as predictors of individual errors made by trainees when detecting masses in mammograms.Methods:Ten radiology trainees and three expert breast imagers reviewed 100 mammograms comprised of bilateral medial lateral oblique and craniocaudal views on a research workstation. The cases consisted of normal and biopsy proven benign and malignant masses. For cases with actionable abnormalities, the experts recorded breast (density and axillary lymph nodes) and mass (shape, margin, and density) features according to the BI‐RADS lexicon, as well as the abnormality location (depth and clock face). For each trainee, a user‐specific multivariate model was constructed to predict the traineeˈs likelihood of error based on BI‐RADS features. The performance of the models was assessed using area under the receive operating characteristic curves (AUC).Results:Despite the variability in errors between different trainees, the individual models were able to predict the likelihood of error for the trainees with a mean AUC of 0.611 (range: 0.502–0.739, 95% Confidence Interval: 0.543–0.680,p < 0.002).Conclusions:Patterns in detection errors for mammographic masses made by radiology trainees can be modeled using BI‐RADS features. These findings may have potential implications for the development of future educational materials that are personalized to individual trainees.
Enzyme-Linked Immunospot Assay for Detection of Human Respiratory Syncytial Virus F Protein-Specific Gamma Interferon-Producing T Cells
Authors: Patton Kathryn , Aslam Shahin , Lin Jim , Yu Li , Lambert Stacie , Dawes Glenn , Esser Mark T. , Woo Jennifer , Janetzki Sylvia , Cherukuri Anu 
Published: February 2014

ABSTRACTRespiratory syncytial virus (RSV) causes significant disease in elderly adults, and we have previously reported that individuals 65 years of age and older have reduced RSV F protein-specific gamma interferon (IFN-γ)-producing T cells compared to healthy younger adults. To measure RSV F-specific memory T cell responses in the elderly following infection or vaccination, we optimized and qualified an IFN-γ enzyme-linked immunospot (ELISPOT) assay. Since peripheral blood mononuclear cells (PBMC) from the elderly could be more fragile, we established optimal cryopreservation techniques and minimal viability acceptance criteria. The number of cells per well, types and concentrations of stimulation antigens, and incubation times were evaluated to maximize assay sensitivity and precision. The optimized assay uses 300,000 cells/well, 2 μg/ml of an RSV F peptide pool (RSV Fpp), and incubation for 22 ± 2 h in serum-free CTL-Test medium. The assay was qualified by 3 analysts using 3 RSV F-responding donor PBMC samples (high, medium, and low responders) tested on 5 different assay days. The assay sensitivity or limit of detection (LOD) was determined to be 21 spot-forming cells (SFC) per 106PBMC, and the lower limit of quantitation (LLOQ) was estimated to be 63 SFC/106PBMC. The intra- and interassay percent coefficients of variation (CV) were <10.5% and <31%, respectively. The results of the qualification study demonstrate that a robust, precise, and sensitive IFN-γ ELISPOT assay has been developed that is fit for measuring RSV F-specific IFN-γ T cell responses in subjects enrolled in a vaccine clinical trial or in epidemiology studies.
Antibodies to the HMW1/HMW2 and Hia Adhesins of Nontypeable Haemophilus influenzae Mediate Broad-Based Opsonophagocytic Killing of Homologous and Heterologous Strains
Authors: Winter Linda E. , Barenkamp Stephen J. 
Published: February 2014

ABSTRACTThe HMW1/HMW2 and Hia proteins are highly immunogenic surface adhesins of nontypeableHaemophilus influenzae(NTHi). Approximately 75% of NTHi strains express HMW1/HMW2 adhesins, and most of the remaining 25% express an Hia adhesin. Our objective in this study was to assess the ability of antisera raised against purified HMW1/HMW2 proteins or recombinant Hia proteins to mediate opsonophagocytic killing of a large panel of unrelated NTHi strains. Native HMW1/HMW2 proteins were purified from three HMW1/HMW2-expressing NTHi strains. Recombinant fusion proteins expressing surface-exposed segments of either of two prototype Hia proteins were purified fromEscherichia colitransformants. Immune sera raised in guinea pigs were assessed for their ability to mediate killing of NTHi in an opsonophagocytic assay with the HL-60 phagocytic cell line. The three HMW1/HMW2 antisera mediated killing of 22 of 65, 43 of 65, and 28 of 65 unrelated HMW1/HMW2-expressing NTHi strains, respectively. As a group, the three sera mediated killing of 48 of 65 HMW1/HMW2-expressing strains. The two Hia immune sera mediated killing of 12 of 24 and 13 of 24 unrelated Hia-expressing NTHi strains, respectively. Together, they mediated killing of 15 of 24 Hia-expressing strains. Neither the HMW1/HMW2 nor the Hia antisera mediated killing of NTHi expressing the alternative adhesin type. Antibodies directed against native HMW1/HMW2 proteins and recombinant Hia proteins are capable of mediating broad-based opsonophagocytic killing of homologous and heterologous NTHi strains. A vaccine formulated with a limited number of HMW1/HMW2 and Hia proteins might provide protection against disease caused by most NTHi strains.
Septic Arthritis of a Native Knee Joint Due to Corynebacterium striatum
Authors: Westblade Lars F. , Shams Farah , Duong Scott , Tariq Oosman , Bulbin Alan , Klirsfeld Dava , Zhen Wei , Sakaria Smita , Ford Bradley A. , Burnham Carey-Ann D. , Ginocchio Christine C. 
Published: February 2014

ABSTRACT

We report a case of septic arthritis of a native knee joint due to
Corynebacterium striatum
, a rare and unusual cause of septic arthritis of native joints. The isolate was identified by a combination of phenotypic, mass spectrometric, and nucleic acid-based assays and exhibited high-level resistance to most antimicrobials.
Use of Mycobacteriophage Quantitative PCR on MGIT Broths for a Rapid Tuberculosis Antibiogram
Authors: Foongladda Suporn , Klayut Wiphat , Chinli Rattapha , Pholwat Suporn , Houpt Eric R. 
Published: February 2014

ABSTRACT

Phenotypic culture-based drug susceptibility testing (DST) for
Mycobacterium tuberculosis
is a valuable tool to identify four to six active drugs for individualized multidrug-resistant (MDR) tuberculosis (TB) regimens. Current culture-based methods are slow, however; therefore, we evaluated a rapid mycobacteriophage-based quantitative PCR (qPCR) assay for use directly on
M. tuberculosis
-positive MGIT broths. We compared phage qPCRs, using a simple cutoff of 3 for the ΔCq value (where Cq is quantification cycle, and ΔCq is calculated as the Cq of starting phage minus the Cq of TB isolates in drug-containing medium), on 325 clinical
M. tuberculosis
MGIT broth cultures versus the respective subcultured isolates tested by agar proportion. The median accuracy for the 13 drugs/concentrations tested was 98%, with most discrepancies being false-resistant results. Evaluation of phage qPCR on greater numbers of resistant strains of 393 isolates grown on Löwenstein-Jensen medium showed similar findings, with a median accuracy, sensitivity, and specificity of 97%, 90%, and 99%, respectively. This rapid culture-based DST methodology can be performed for any drug on TB-positive MGIT broths, with a specimen-to-antibiogram turnaround time of approximately 23.9 days, compared with waiting 58.6 days for isolate growth on solid medium followed by agar proportion DST.
Brown Planthopper Nudivirus DNA Integrated in Its Host Genome
Authors: Cheng Ruo-Lin , Xi Yu , Lou Yi-Han , Wang Zhuo , Xu Ji-Yu , Xu Hai-Jun , Zhang Chuan-Xi 
Published: February 2014

ABSTRACT

The brown planthopper (BPH),
Nilaparvata lugens
(Hemiptera:Delphacidae), is one of the most destructive insect pests of rice crops in Asia. Nudivirus-like sequences were identified during the whole-genome sequencing of BPH. PCR examination showed that the virus sequences were present in all of the 22 BPH populations collected from East, Southeast, and South Asia. Thirty-two of the 33 nudivirus core genes were identified, including 20 homologues of baculovirus core genes. In addition, several gene clusters that were arranged collinearly with those of other nudiviruses were found in the partial virus genome. In a phylogenetic tree constructed using the supermatrix method, the original virus was grouped with other nudiviruses and was closely related to polydnavirus. Taken together, these data indicated that the virus sequences belong to a new member of the family
Nudiviridae
. More specifically, the virus sequences were integrated into the chromosome of its insect host during coevolution. This study is the first report of a large double-stranded circular DNA virus genome in a sap-sucking hemipteran insect.

IMPORTANCE
This is the first report of a large double-stranded DNA virus integrated genome in the planthopper, a plant sap-sucking hemipteran insect. It is an exciting addition to the evolutionary story of bracoviruses (polydnaviruses), nudiviruses, and baculoviruses. The results on the virus sequences integrated in the chromosomes of its insect host also represent a story of successful coevolution of an invertebrate virus and a plant sap-sucking insect.