bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seroprevalence and genetic characterization of Toxoplasma gondii in domestic pigs intended for human consumption in Cuba
Authors: Castillo‐Cuenca Julio César , Almería Sonia , Calero‐Bernal Rafael , Fernández‐Escobar Mercedes , Fraga Jorge , Entrena‐García Angel , Arias Pedro Casanova , Martínez‐Moreno Álvaro , García‐Bocanegra Ignacio 
Published: November 2022

AbstractDomestic pigs are considered as one of the main intermediate hosts in the zoonotic transmission of Toxoplasma gondii in many countries. Serological and molecular studies are warranted to better understand the epidemiology and transmission patterns of this parasite worldwide. To date, seroepidemiological information on T. gondii in domestic pigs in Cuba is very scarce and there are no reports of T. gondii genotypes circulating in this country. Here, we aimed to estimate the seroprevalence of T. gondii and provide genetic characterization of the strains circulating in slaughtered pigs intended for human consumption in Central Cuba. Seroprevalence was determined in 450 serum samples from slaughtered pigs in Villa Clara province using ELISA. Anti‐Toxoplasma gondii IgG antibodies were detected in 100 animals (22.2%, 95% CI: 18.5–26.2). Conventional PCR of the 529‐bp marker of T. gondii was performed in hearts and diaphragm tissues of all ELISA‐seropositive pigs. Toxoplasma gondii DNA was detected in four animals. Further genetic characterization of the positive DNA samples was performed by multilocus PCR‐RFLP and PCR‐sequencing typing tools. Molecular analysis revealed four different genetic profiles that were combinations of type I, II, III and u‐1 alleles, suggesting the circulation of non‐clonal genotypes of T. gondii in domestic pigs in Cuba. Our results indicate that T. gondii is widely distributed in slaughtered pigs in this country, which might have important implications for public health. To the best of our knowledge, this is the first report on genetic characterization of T. gondii in Cuba. Although preliminary, the results suggest a high genetic diversity of T. gondii in the study region. Further studies based on parasite isolation are needed to definitively identify the genotypes circulating and characterize the virulence of strains detected in pigs in Cuba, and to assess the risk of zoonotic transmission from pork products in this country.
Spatial and Temporal Mapping of Articular Cartilage Poro-Viscoelastic Material Properties Using Indentation
Authors: Valluru Pranay Kumar Reddy , Su Alison , Mehta Shikhar , Bajpayee Ambika , Shefelbine Sandra 
Published: November 2022

Abstract
Biphasic poro-viscoelastic constitutive material model (BPVE) captures both the fluid flow dependent and independent behavior of cartilage under stress relaxation type indentation. A finite element model based on BPVE formulation was developed to explore the sensitivity of the model to Young's modulus, Poisson's ratio, permeability, and viscoelastic constitutive parameters expressed in terms of Prony series coefficients. Then we fit the numerical model to experimental force versus time curves from stress relaxation indents on bovine tibial plateaus to extract the material properties. Measurements were made over the period of two days to capture the material property changes that resulted from trypsin-induced degradation. We measured spatial and temporal changes in mechanical properties in the cartilage. The areas of degradation were characterized by an increase in both permeability and summation of Prony series shear relaxation amplitude constants. These findings suggest that cartilage degradation reduces the intrinsic viscoelastic properties of the solid phase of the tissue in addition to impairing its capacity to offer frictional drag to the interstitial fluid flow (permeability). The changes in material properties are measurable well before structural degradation occurs.
Direct Injection Strategy to Extend the Lean Limit of a Passive Pre-Chamber
Authors: Almatrafi Fahad , Uddeen Kalim , Ben Houidi Moez , Cenker Emre , Turner James 
Published: November 2022

Abstract
Lean operation increases the efficiency of the Otto-cycle internal combustion engine and decreases its emissions. However, increasing the air-fuel ratio beyond stoichiometry requires higher ignition energy to maintain the stable operation of the engine. The pre-chamber emerges as one of the promising enablers of lean operation, providing much larger energy into the main combustion chamber than simple a spark plug at multiple sites to increase combustion stability. Pre-chambers are classified into two categories based on their fuel input; active pre-chambers, with a dedicated fuel injection system, and passive pre-chambers, which are solely charged with the main chamber air-fuel mixture through nozzle holes. Therefore, the passive pre-chamber type is favorable for existing engines because of its compact design and limited modification requirements. Nevertheless, passive pre-chambers have issues with igniting very lean mixtures. In this study, a single-cylinder light-duty engine is used to study the possibility of extending the lean limit of the passive pre-chamber using a split direct injection (DI) strategy and indirect enrichment of the pre-chamber mixture. The results of the split injection method were then compared to port fuel injection (PFI) measurements. Also, another set of experiments was performed with a standard spark plug using PFI and split DI for comparison. The results showed an increase in the lean limit of passive pre-chamber operation when using the split DI strategy compared to PFI, from λ = 1.5 to 1.7. However, increased soot production was observed when using the split injection strategy.
A Design Approach of a Dedicated EGR-System for a Naturally Aspirated Gas Engine - From 1D Engine Process Simulation and Design of Experiments Up to the Experimental Validation
Authors: Beltaifa Youssef , Kettner Maurice , Eilts Peter , Ruchel Bosse 
Published: November 2022

Abstract
This work presents a systematic approach proceeding from the engine process simulation (1D-CFD) and design of experiments (DoE) up to the experimental validation to build a dedicated exhaust-gas recirculation (EGR) system for a stationary four-cylinder naturally aspirated gas engine. This system should ensure an equal distribution of the recirculated exhaust gas, coming entirely from the rich-operated dedicated cylinder. The rich combustion enables an in-cylinder production of highly reactive species (mainly H2 and CO), resulting in increased EGR reactivity, which improves the dilution tolerance, leading to reduced wall heat losses and lower knock tendency in the EGR receiving cylinders.
However, the EGR system design represents a challenge due to the pulsating exhaust gas flow from the dedicated cylinder, which leads to a considerable EGR maldistribution in the receiving cylinders. A numerical analysis of this effect demonstrated, that the EGR distribution uniformity depends on the design and dimensions of the EGR path. Considering the numerous design parameters and taking into account that the optimum design of the EGR path is not necessarily the sum of optima from the one-factor-at-a-time variations, efficient DoE methodologies were applied. They enabled identifying the optimum set of the EGR path design-parameters, with an EGR rate maldistribution of about 1%-points.
To evaluate the quality of the numerical results, the dedicated EGR path with the optimum parameters set was built on the engine test bench. The experimental results confirm the simulative prediction accuracy, demonstrating the reliability of the pursued approach.
Study of Injector Geometry and Parcel Injection Location on Spray Simulation of the ECN Spray G Injector
Authors: Kumar Aman , Van Dam Noah 
Published: November 2022

Abstract
Parcel-based simulations are the most common method to simulate fuel sprays, especially for reacting conditions, due to their lower computational cost compared to more highly resolved simulations. It is important, however, to understand how spray boundary conditions used to initialize the parcels that represent the atomizing fluid affect downstream conditions and overall simulation performance. Traditionally, when parcel simulations are used, the injector tip geometry is either significantly simplified or removed altogether due to resolution limits. Recent advances in computational power and numerical methods, however, have made it possible to resolve flow through these features. Previous work has shown some potential effects of even simple injector tip geometries, and this study investigates the effect of very detailed nozzle geometries on parcel-based simulations that have typically ignored these details. Four different parameters were investigated: whether a simulation includes a detailed injector tip geometry, or a flat surface; whether parcels are initialized at the counterbore exit, which is more common, or at the nozzle exit; the use of an experimentally-derived rate of injection or one-way coupling with a separate internal nozzle VOF simulation; the use of nominal or measured injector geometry. Simulations were compared using both global penetration as well as local data near the injector. Spray penetration and other global measures showed limited sensitivity to boundary conditions/initialization procedure, but local data such as the local liquid volume fraction showed greater variation between the conditions, which may have an impact on mixing and combustion predictions in engine applications.
Aerosol Separation and Pressure Control of a Smart Crankcase Ventilation System
Authors: Nowak Niclas , Sirtl Christian , Rymann Othmar , Flynn Paul , Stieler Christian , Heller Marc-Tran 
Published: November 2022

Abstract
Crankcase ventilation systems are coming into new focus due to safety concerns associated with alternative fuels such as ammonia and hydrogen. In addition, innovation is being driven by increasingly stringent legislation that plays an important role in limiting crankcase emissions. This study characterizes aerosol separation and pressure control of a modern crankcase ventilation system, which is referred to as “smart” due to enabling monitoring, diagnostics, and predictive maintenance. Experiments were conducted on custom-built and commercial test rigs that mimic the physical conditions to which crankcase ventilation systems are subjected. The main findings were that the pressure drop of the filter media followed the profile described by the “jump-and-channel model”, also indicating the presence of an oil film. However, such an oil film was not detected on the full-size element, which had a positive effect on the pressure drop. Excellent separation efficiencies around 99.9% were achieved for all flow rates and filter conditions. In addition, re-entrainment of oil was not detected. The electronic pressure regulator (EPR) was found to accurately (± 1 mbar) adjust the crankcase pressure to the required level. Moreover, the fully open EPR featured a low differential pressure of about 1 mbar, which effectively reduces crankcase peak pressure during engine startup. These features exceed those of conventional pressure control valves. In addition, only the electronic regulator enables “smart” features.
A CFD Study on Mixture Preparation and Combustion in a Heavy-Duty Locomotive Diesel Engine at High Load Condition
Authors: Addepalli Srinivasa Krishna , Magnotti Gina M. , Som Sibendu , Sheth Pushkar , Jayakar Vijayaselvan , Klingbeil Adam , Lavertu Thomas 
Published: November 2022

Abstract
Diesel engines are one of the most commonly used combustion systems for heavy-duty applications like locomotives. Although computational fluid dynamics (CFD) modeling of diesel engines is a mature research topic, CFD modeling of large-bore engines like those used in locomotives has not been as extensively studied as their smaller bore on-road and stationary counterparts. The present paper aims at identifying and outlining best practices for performing 3D CFD simulations of locomotive diesel engines and comparing them with the established best practices for heavy-duty diesel engines in the literature. The locomotive diesel engine considered in this study has a bore of 168mm and operates at speeds of up to 1800 rpm. Open cycle engine CFD simulations were carried out for both motored and fired cases. Two turbulence models viz., Re-Normalization group (RNG) k-ε model and Reynolds stress model (RSM) were used in this study to assess their performance. The fuel spray break up was modelled using Kelvin Helmholtz and Rayleigh Taylor (KH-RT) model. A grid and statistical convergence study was performed to assess the effect of mesh size on the predicted results. It was found that a minimum cell size of 0.25 mm near the fuel spray and 1 mm in the rest of the cylinder was sufficient to achieve grid convergence in terms of spray and combustion characteristics. The boundary wall temperatures are shown to affect the in-cylinder pressure predictions. Higher wall temperatures were found to reduce the trapped mass and increase the peak motored pressure. The CFD model was validated by comparing the simulation results with the experimental measurements at full rated power. It was found that the RSM was able to capture the combustion characteristics more accurately compared to RNG k-ε model. Overall, the CFD model was able to predict the engine combustion and performance characteristics at three injection timings.
Effect of Ethanol Addition on the Laminar Burning Velocity of Gasoline Surrogates With Toluene
Authors: Shankar Varun , Fang XiaoHang , Hinton Nathan , Davy Martin , Leach Felix 
Published: November 2022

Abstract
Laminar burning velocity (LBV) is a crucial parameter in many practical combustion simulations, and the acquisition of LBVs is a critical step for evaluating potential alternative fuels and/or suitable surrogates. Ethanol is regarded as one of the most promising alternative fuels, particularly for spark ignition engines, as it may be produced from renewable biomass. While there exists data showing the pressure dependence on ethanol’s LBV compared to iso-octane and n-heptane (primary reference fuels (PRFs)), the relative magnitude of the pressure dependence of LBV between ethanol and toluene has not been established. The inclusion of toluene is important because commercial gasoline has significant levels of aromatics. In this work, common gasoline surrogate components of iso-octane, n-heptane, toluene, and ethanol were studied as pure compounds and in equal volume binary, ternary, and quaternary mixtures. Experiments are conducted in a spherical combustion bomb at elevated temperatures (380 K and 450 K) and pressures (1 to 4 bar). Under these conditions, ethanol and n-heptane present faster LBVs than iso-octane and toluene, particularly at 450 K. Ethanol and iso-octane present strong pressure dependence, with this effect accentuated at higher temperature conditions. As equal volume mixtures were studied, the effect of these distinct behaviours was examined in comparison to chemical kinetic predictions and widely used mixing rules.
A Computational Assessment of Combustion Submodels for Predictive Simulations of Pre-Chamber Combustion Engines
Authors: Silva Mickael , Liu Xinlei , Hlaing Ponnya , Cenker Emre , Turner James , Im Hong G. 
Published: November 2022

Abstract
Pre-chamber combustion (PCC) modeling has been progressing in recent years, while there are lingering questions on fundamental modeling aspects, whether a flame-based or an ignition-based model predicts the combustion with higher fidelity. This mode of ignition concept is known to enable a stable engine operation at ultralean conditions with a short combustion duration, thus enhancing engine efficiency. The current work utilizes computational fluid dynamics to assess well-known combustion models: multi-zone well-stirred reactor (MZ-WSR) and G-Equation. The former models combustion as an ignition-based phenomenon while the latter as a flame propagation type of combustion. A pre-chamber containing twelve nozzles divided into two layers on a narrow throat was chosen. The jets from the two layers of nozzles and the local thermodynamic conditions differ substantially, which makes it a suitable configuration for assessing the predictive capabilities of distinct combustion models. The fuel utilized was methane and the global air-fuel ratio (λ) was varied, ranging from global-λ of 1.6, 1.8, and 2.0, and the total fuel injected through the pre-chamber was varied for one of the cases (3%, 7%, and 13%). The results suggest that both combustion models can potentially match experimental engine performance data upon appropriate calibration; however, fundamental differences in jet topology arise since the G-Equation formulation accounts for turbulence-chemistry interaction, while MZ-WSR does not.
Experimental Investigation of Gasoline Direct Injection (GDI) Sprays Using Diffused Back Illumination (DBI) and Structured Laser Illumination Planar Imaging (SLIPI) Techniques
Authors: Gaur Anurag , Ailaboina Akhil , Saha Kaushik 
Published: November 2022

Abstract
A large share of passenger vehicles are currently running on gasoline, which is considered the major contributor to carbon emissions from the transportation sector. In gasoline direct injection (GDI), the fuel is introduced directly into the combustion chamber in a spark ignition (SI) engine. GDI has the advantage of operating at a higher compression ratio due to the charge cooling effect, resulting in better fuel utilization and lower pollutant emissions. The spray formed from fuel injection under different engine running conditions governs the charge (air-fuel) characteristics. The present work focuses on experiments using a GDI system with a multi-hole injector for gasoline fuel sprays in a constant volume chamber. The saturation pressure of the fuel present within the nozzle increases with rising temperature (80 to 90°C) from heat transfer due to the placement of the injector directly into the combustion chamber. At part-load running conditions, when the heated fuel injected into an environment has a pressure sufficiently lower (achieved in early injection) than its saturation pressure, it attains the state of superheating and undergoes flash boiling. The abrupt vaporization of injected fuel results from flash boiling and affects spray characteristics. The ratio of chamber pressure to saturation pressure (Pch/Psat) indicates the propensity of flashing for a given super-heated operating condition. Macroscopic analysis of GDI sprays is reported in this study under flashing and non-flashing conditions through different experimental techniques to provide a comprehensive understanding. Experimental studies reported in this kind of literature typically adopt a specific technique to elucidate the details of spray evolution.
A Diffused Back Illumination (DBI) imaging technique with a low-speed Nd: YAG laser has been carried out to analyse the liquid phase of the spray, such as penetration, cone angle, and width. Additionally, a novel Structured Laser Illumination Planar Imaging (SLIPI) technique has been adopted to identify the relatively dense spray regions by addressing the difficulty due to multiple scattering of light illuminating from surrounding scatterer media (droplets). SLIPI is used to suppress the effect of the surrounding light artefacts, helping explore the structure in a new dimension. A multi-plume spray is expected to have voids, dense, and dilute portions at different locations, affecting the fuel mixture, and interestingly, it appears after subduing the effects of multi-scattering from a modulated laser sheet using SLIPI. An LED-based spray illumination was also used to compare the DBI and SLIPI results to better understand the utility and effectiveness of different imaging techniques in a densely populated and highly transient spray phenomenon.
Investigations Into the Performance and Emissions Characteristics of FT Synthetic Aviation Fuel, Isoparaffinic Kerosene (IPK), in a Single-Cylinder Indirect Injection (IDI) Engine
Authors: Soloiu Valentin , Weaver Amanda , Parker Lily , Smith Richard , Brant Austin , Brock Dillan , Ilie Marcel 
Published: November 2022

Abstract
In this study, iso-paraffinic kerosene (IPK) was analyzed for ignition delay, combustion delay, pressure trace, pressure rise rate and, apparent heat release rate in an experimental single cylinder indirect injection (IDI) compression ignition engine as well as in a constant volume combustion chamber (CVCC). Neat IPK, neat ULSD, and a by-mass blend of 50%IPK50%ULSD were analyzed in a CVCC and an IDI engine to determine the effect of Derived Cetane Number (DCN), Ignition Delay (ID), and Low Temperature Heat Release (LTHR) on combustion timing and engine knock.
In the CVCC, IPK was found to have a significantly lower DCN than ULSD at 26 and 47, respectively. The blend was found to have a DCN between the two neat fuels at 37.5. Additionally, the ignition delay increased in the CVCC from 3.56 ms for ULSD to 5.3 ms for IPK with the blend falling between the two at 4.38 ms.
For engine research, the single-cylinder experimental IDI engine was run at 2400 rpm at 5, 6, and 7 Indicated Mean Effective Pressure (IMEP) using each of the three researched fuels. It was found that when running neat IPK, there was a profound level of engine knock at all loads characterized by the 60% increase in the Peak Pressure Rise Rate (PPRR) when compared to ULSD. The pressure trace for IPK at all loads showed a significant delay in combustion due to IPK’s resistance to autoignition. This was observed in the increasing ignition delay in the engine from 0.88 ms for ULSD to 1.1 ms at 7 bar IMEP for IPK. Despite the delay in ignition for IPK, all three researched fuels reached peak Apparent Heat Release Rate (AHRR) at approximately 370° leading to a much more rapid increase in AHRR for IPK when compared to ULSD. This steep slope in the AHRR, also seen in the increased PPRR, and longer ID caused the high levels of engine knock, observed as oscillations in the pressure trace which decreased in magnitude as IMEP increased.
Development of a Liquid-Phase LPG Delivery System for Direct Injection, Spark-Ignited Engines
Authors: Kar Tanmay , Fosudo Toluwalase , Windom Bret , Olsen Daniel , Hoke Jensen , Rogers Jeff 
Published: November 2022

Abstract
Liquefied petroleum gas (LPG) is a promising diesel fuel alternative for heavy-duty vehicle applications due to its CO2 reduction potential, high knock resistance, easy liquefication capability, and lower fuel cost. Direct injection (DI) of liquid-phase LPG has emerged as a promising technology in spark-ignited (SI) engines due to the benefits from the in-cylinder charge cooling effect in comparison to external mixture formation systems. But this DI LPG technology requires a fuel delivery system that can supply the desired amount of LPG fuel in the liquid state at high pressure.
This work first describes the design and component integration of an LPG fuel system that delivers fuel from the tank to the injector in the liquid state at around 172 bar, mainly focusing on thermal management aspects to avoid multi-phase behavior within the system. A detailed description of the injector developmental work, from reverse engineering of stock injectors to manufacturing a prototype LPG direct injector, is also presented, including nozzle modifications to accommodate a high LPG flow rate for heavy-duty applications. A one-dimensional (1D) flow model of the fuel delivery system is developed using the MATLAB/Simulink software platform to guide the selection and sizing of components and characterize the prototype injector. Bench testing of the fuel delivery system is performed with the unmodified stock and prototype LPG injectors using a Viscor calibration fluid and LPG to study the effect of fuel pressure and current profiles on the injected fuel quantity. The simulation models are shown to be capable of predicting the experimental results. Durability tests are also performed to understand the failure modes of different components in the fuel delivery system.