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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
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    <item>
      <title>Effect of first-stage ignition on the onset of knocking in SI engines</title>
      <link>https://trid.trb.org/View/2325589</link>
      <description><![CDATA[Knocking limits the performance and efficiency of highly compressed, downsized spark ignition combustion engines. In this paper, the effect of the first-stage ignition on knock is analyzed using a quasi-dimensional engine model. The standard coherent flame model is used for turbulent combustion, and five available reduced chemical kinetics mechanisms are applied to thermal ignition of the end-gas. Measurements in a modified CFR engine operating with two PRF mixtures are used to test the predictive ability of the models and to identify the conditions that lead to knocking. Although the chemical kinetics models used predict similar autoignition delay curves, they do not result in the same knock predictions. The results show that the chemistry must correctly capture the NTC range to predict the observed onset of knocking. In addition, the chemistry models are used to determine the first- and second-stage ignition delay times and their dependence on engine speed and compression ratio. Results show that the autoignition stages occur at relatively fixed temperatures, independent of engine speed and compression ratio. A sensitivity analysis shows that only one set of reactions in the low-temperature chemistry contributes to first-stage ignition, which in turn determines the onset of knocking. This suggests that fuel additives that inhibit or delay the inflection in the NTC region from low- to high-temperature could prevent knock in SI engines.]]></description>
      <pubDate>Fri, 15 Mar 2024 16:35:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/2325589</guid>
    </item>
    <item>
      <title>Experimental Research of Various Evaluation Indices on Predicting the Influences of Internal and External Factors on Asphalt-Filler Interaction Ability</title>
      <link>https://trid.trb.org/View/2129203</link>
      <description><![CDATA[The physicochemical interaction between asphalt binder and mineral filler plays a key role in deciding the rheological responses of asphalt mastic. Currently, several indices have been proposed to quantify asphalt-filler interaction ability, such as ΔG, K-B-G, and Kₑ based on complex modulus as well as K-B-δ and L-A-δ dependent on phase angle. Much research has confirmed that asphalt-filler interaction degree is closely related to internal and external factors, including asphalt binder and filler characteristics, filler concentration, temperature, and so on. Therefore, investigating whether current indices could accurately describe the influences of these factors on asphalt-filler interaction ability is a significant aspect evaluating their accuracy and feasibility. To this end, the rheological parameters of asphalt binder and corresponding mastics were measured and used to calculate different evaluation indices. The results showed that ΔG, K-B-G, and Kₑ exhibited superior performance on accurately reflecting the effects of external factors by comparison in K-B-δ and L-A-δ. For the internal factors, the indices based on complex modulus could successfully distinguish the interaction ability difference of asphalt binder with active and inert fillers, whereas only ΔG presented excellent performance in terms of measuring the asphalt-filler interaction ability with filler concentration changing. In addition, all of the indices failed to distinguish the interaction degree difference of filler to Pen70 and Pen90 asphalts except certain test conditions, indicating the modification of current indices should consider asphalt components.]]></description>
      <pubDate>Mon, 24 Apr 2023 16:19:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/2129203</guid>
    </item>
    <item>
      <title>Experimental and Modeling Investigation of NO Formation Mechanism for Biodiesel and Its Blend with Methanol</title>
      <link>https://trid.trb.org/View/1598307</link>
      <description><![CDATA[Biodiesel makes an attractive option to replace fossil diesel owing to its applicability in diesel engines without major modifications. An increase in NO emissions with biodiesel compared to diesel is a major concern for its wider use. Blending alcohols, such as methanol, with biodiesel is a potential remedy to mitigate NO formation, as suggested by experiments. However, computational investigations studying the effect of biodiesel-methanol blends on NO formation are scarce. A combined experimental and computational approach is adopted here to investigate the NO formation mechanism with neat biodiesel and biodiesel-methanol blend fueled light duty diesel engine. Firstly, a new compact kinetic model is utilized consisting of oxidation reactions for methyl butanoate and n-dodecane as a surrogate for biodiesel. A surrogate is defined to represent biodiesel based on a combined property and functional group based approach. This kinetic scheme is comprehensively validated for its component kinetics and available fundamental combustion experiments for biodiesel. Later, the suitability of the surrogate and the associated kinetic model is examined at engine conditions by comparing the predicted 3D CFD engine simulations with experiments for combustion and emission characteristics of neat biodiesel. The simulations performed using the surrogate show a good agreement with the experiments. Finally, a methanol sub-mechanism is incorporated in the biodiesel surrogate to investigate the effects of biodiesel-methanol blend. The addition of methanol causes minimal changes in the gross combustion parameters as shown by experiments as well as computations. However, it results in significant decrease in NO concentration, which is qualitatively captured by engine simulations. The computations provide additional insight into this effect providing a possible explanation for reduction in NO concentration with addition of methanol to biodiesel.       ]]></description>
      <pubDate>Tue, 28 May 2019 09:47:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/1598307</guid>
    </item>
    <item>
      <title>Comparison of Kinetic Mechanisms for Numerical Simulation of Methanol Combustion in DICI Heavy-Duty Engine</title>
      <link>https://trid.trb.org/View/1598301</link>
      <description><![CDATA[The combustion process in a homogeneous charge compression ignition (HCCI) engine is mainly governed by ignition wave propagation. The in-cylinder pressure, heat release rate, and the emission characteristics are thus largely driven by the chemical kinetics of the fuel. As a result, CFD simulation of such combustion process is very sensitive to the employed reaction mechanism, which model the real chemical kinetics of the fuel. In order to perform engine simulation with a range of operating conditions and cylinder-piston geometry for the design and optimization purpose, it is essential to have a chemical kinetic mechanism that is both accurate and computational inexpensive. In this paper, we report on the evaluation of several chemical kinetic mechanisms for methanol combustion, including large mechanisms and skeletal/reduced mechanisms. These mechanisms are evaluated in terms of homogeneous ignition delay time, laminar flame speed, and multi-phase simulations of HCCI heavy-duty engine. The results are compared with experimental data and evaluated in terms of the accuracy and computational cost. It was found that scattering of ignition delay time predicted from different chemical kinetic mechanisms reported in the literature under homogeneous mixture ignition conditions give rise to a high sensitivity of the engine in-cylinder pressure prediction to the selected mechanism.       ]]></description>
      <pubDate>Tue, 28 May 2019 09:47:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/1598301</guid>
    </item>
    <item>
      <title>SI Engine Combustion and Knock Modelling Using Detailed Fuel Surrogate Models and Tabulated Chemistry</title>
      <link>https://trid.trb.org/View/1598298</link>
      <description><![CDATA[In the context of today’s and future legislative requirements for NOx and soot particle emissions as well as today’s market trends for further efficiency gains in gasoline engines, computational fluid dynamics (CFD) models need to further improve their intrinsic predictive capability to fulfill OEM needs towards the future. Improving fuel chemistry modelling, knock predictions and the modelling of the interaction between the chemistry and turbulent flow are three key challenges to improve the predictivity of CFD simulations of Spark-Ignited (SI) engines. The Flamelet Generated Manifold (FGM) combustion modelling approach addresses these challenges. By using chemistry pre-tabulation technologies, today’s most detailed fuel chemistry models can be included in the CFD simulation. This allows a much more refined description of auto-ignition delays for knock as well as radical concentrations which feed into emission models, at comparable or even reduced overall CFD run-time. The FGM model has a high level of intrinsic predictive capability, as already demonstrated for many academic cases as well as for industrial burners, gas turbines and diesel engines. The application to gasoline engines has not been much investigated however, mainly due to the difficulty of model implementation and chemistry tabulation technology.         In this work, the FGM combustion model is assessed on multiple operating points of a modern SI engine, using various levels of detail for the fuel chemistry, ranging from industry-standard reduced chemical schemes to state-of-the-art gasoline surrogate models. The investigated configuration represents a turbocharged gasoline engine with direct injection and homogeneous charge combustion. The engine simulation involved gas-exchange, fuel spray injection, spark ignition and combustion phases. The computational grid provides a mesh resolution in the range of 0.6-0.3 mm within the cylinder.         CFD simulation has been started at the beginning of the exhaust stroke allowing to correctly predict the residual gas mass fraction, the mixture fraction as well as the temperature field - the parameters, which can directly affect the knocking effects. Firstly, the comparison between the simulated pressure curves and available experimental data for a spark timing sweep was discussed. The special attention was dwelled on an ability of the FGM based knock model to characterize the inherent knock combustion features including a knock probability and providing an information on knock cycle indicator.       ]]></description>
      <pubDate>Tue, 28 May 2019 09:47:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/1598298</guid>
    </item>
    <item>
      <title>Effect of Turbulence-Chemistry Interaction on Spray Combustion: A Large Eddy Simulation Study</title>
      <link>https://trid.trb.org/View/1598296</link>
      <description><![CDATA[Although turbulence plays a critical role in engines operated within low temperature combustion (LTC) regime, its interaction with chemistry on auto-ignition at low-ambient-temperature and lean-oxygen conditions remains inadequately understood. Therefore, it is worthwhile taking turbulence-chemistry interaction (TCI) into consideration in LTC engine simulation by employing advanced combustion models. In the present study, large eddy simulation (LES) coupled with linear eddy model (LEM) is performed to simulate the ignition process in n-heptane spray under engine-relevant conditions, known as Spray H. With LES, more details about unsteady spray flame could be captured compared to Reynolds-averaged Navier-Stokes equations (RANS). With LEM approach, both scalar fluctuation and turbulent mixing on sub-grid level are captured, accounting for the TCI. A skeletal mechanism is adopted in this numerical simulation, including 41 species and 124 reactions. Validations is carried out and numerical results show good agreement with experimental data. It is found that, Damköhler number (Da) at the onset of high temperature reaction evidently decreases as ambient temperature and oxygen reduces. Consequently, combustion mode varies from flamelet regime to slow chemistry regime, where the competitive effect between turbulent mixing and chemistry is more evident. Besides, scalar fluctuation has promoting effect on low temperature reaction, which is responsible for the over-prediction of ignition delay in low ambient temperature/oxygen condition without consideration of TCI. Further analysis of turbulence intensity on ignition is performed by using three different turbulence intensity. Contrary to what found in premixed combustion, ignition process in spray combustion will be promoted with enhanced small scale turbulence.       ]]></description>
      <pubDate>Tue, 28 May 2019 09:47:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/1598296</guid>
    </item>
    <item>
      <title>A Study on Kinetic Mechanisms of Diesel Fuel Surrogate n-Dodecane for the Simulation of Combustion Recession</title>
      <link>https://trid.trb.org/View/1598295</link>
      <description><![CDATA[Combustion recession, an end of injection (EOI) diesel spray phenomenon, has been found to be a robust correlation parameter for UHC in diesel LTC strategies. Previous studies have shown that the likelihood of capturing combustion recession in numerical simulations is highly dependent on the details of the low-temperature chemistry reaction mechanisms employed. This study aims to further the understanding of the effects of different chemical mechanisms in the prediction of a reactive diesel spray and its EOI process: combustion recession. Studies were performed under the Engine Combustion Network’s (ECN) “Spray A” conditions using the Reynolds-Averaged Navier-Stokes simulation (RANS) and the Flamelet Generated Manifold (FGM) combustion model with four different chemical mechanisms for n-dodecane that are commonly used in the engine simulation communities - including recently developed reduced chemistry mechanisms. The flamelet database for each of the chemical mechanism is generated using two methods: 0D homogeneous reactor (HR) ignition flamelets and 1D igniting counterflow diffusion (ICDF) flamelets. The effect of different tabulation approaches is investigated first following by the discussion of the impact of chemical mechanisms on the prediction of combustion recession. Further discussions include an evaluation of the performance of chemical mechanisms in predicting the most relevant reacting spray characteristics compared to the ECN experimental database: ignition delay time (IDT), flame lift-off length (LOL) and flame reactive region. Results show that the choice of both tabulation method and chemical mechanism play a significant role in initial flame stabilization and end of injection (EOI) transient processes. In general, both tabulation techniques were able to qualitatively capture the flame characteristics before EOI, however ICDF tabulation is better suited for the FGM approach in order to capture combustion recession. Furthermore, the chemical mechanisms studied indicate that mechanisms with stronger low temperature chemistry predictions are more likely to promote combustion recession under an FGM framework.       ]]></description>
      <pubDate>Tue, 28 May 2019 09:47:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/1598295</guid>
    </item>
    <item>
      <title>Role of Supplementary Cementitious Material Type in the Mitigation of Calcium Oxychloride Formation in Cementitious Pastes</title>
      <link>https://trid.trb.org/View/1524077</link>
      <description><![CDATA[Premature deterioration has been observed at some joints in concrete pavements. This joint damage has been attributed, in part, to a deleterious chemical reaction between chloride-based deicing salts (e.g., calcium chloride) and calcium hydroxide from the cementitious matrix resulting in the formation of a compound referred to as calcium oxychloride. Calcium oxychloride formation can be mitigated in cementitious pastes through the replacement of cement with supplementary cementitious materials (SCMs) (e.g., fly ash or slag). Although various SCMs are beneficial in mitigating the formation of calcium oxychloride, little has been written to describe similarities or differences between the different types of SCMs relating to their ability to mitigate calcium oxychloride formation. This paper compares various SCM types. Cementitious pastes were prepared with between 0 and 60% of the cement being replaced (by volume) with SCMs for water-to-cementitious materials ratios (w/cm) of 0.36 and 0.50, which are the lower and upper bounds of the w/cm typically used for pavements and sidewalks. Pastes were cured to develop a high degree of hydration, and subsequently ground to a fine powder for use in thermogravimetric analysis and low temperature differential scanning calorimetry testing to quantify the calcium hydroxide and calcium oxychloride amounts, respectively. The composition of the specific fly ash and slag used influences the calcium hydroxide and calcium oxychloride amounts. As the w/cm increases, calcium hydroxide and calcium oxychloride amounts increase; however, this amount was only between 4 and 30% for the calcium hydroxide and various SCMs. As the volume of supplementary cementitious materials replacing the cement increases, calcium hydroxide and calcium oxychloride amounts decrease. The supplementary cementitious materials reduce the calcium hydroxide and calcium oxychloride formed in the order calcined clay > silica fume ≫ fly ash > slag ≫ limestone. The contributions of the SCMs to reducing calcium hydroxide (CH) and calcium oxychloride (CAOXY) due to dilution and reaction are separated. The potential benefits of different SCMs in reducing calcium hydroxide amounts in paste can be predicted based on their pozzolanicity (determined from their response in pozzolanic tests based on isothermal calorimetry and thermogravimetric analysis).]]></description>
      <pubDate>Mon, 27 Aug 2018 14:06:38 GMT</pubDate>
      <guid>https://trid.trb.org/View/1524077</guid>
    </item>
    <item>
      <title>Molecular Dynamics Modeling and Simulation of Bitumen Chemical Aging</title>
      <link>https://trid.trb.org/View/1495256</link>
      <description><![CDATA[Chemical aging of asphalt binder leads to significant changes in its mechanical and rheological properties, resulting in poor pavement behavior and distress. Various laboratory methods have been used to simulate asphalt aging during the service life of the pavement. However, controversy exists regarding the capability of these methods to predict field aging. Various factors interact with the pavement during service, and the mechanism behind aging is not fully understood. The two main outcomes of chemical aging are oxidation of asphalt molecules, and change in asphalt SARA (saturate, aromatic, resin, and asphaltene) fractions. Reaction of oxygen with asphalt components forms polar viscosity-building molecules, while the change in SARA fractions upsets the balance in asphalt, giving it brittle properties. As both these factors affect the binder at the molecular level, molecular dynamic (MD) simulations can provide core insights into understanding the fundamentals of asphalt aging. This study used MD simulation to investigate the effect of each aging process on the properties of asphalt binder. In that respect, a representative model of virgin binder and eight different models of aged binder were built, including models for laboratory- and field-aged binder. Properties such as density, bulk modulus, glass transition temperature, and viscosity from different MD models were compared to distinguish between the effect of each aging mechanism on binder properties. The results showed that both aging mechanisms lead to an increase in density, bulk modulus, and viscosity of the binder. The SARA fractions of laboratory-aged binder were found to affect bulk modulus and viscosity more dramatically compared to field aged binder. However, when the oxygen content of models was considered, field-aged binder showed a larger increase in bulk modulus and viscosity compared to laboratory-aged binder. This indicates that the dominant mechanism from laboratory aging process is upset in SARA fractions, while oxidation of molecules might be a more dominant mechanism for field-aged binder. No statistically significant difference was observed between the glass transition temperature values for virgin and aged binder.]]></description>
      <pubDate>Mon, 26 Feb 2018 13:44:10 GMT</pubDate>
      <guid>https://trid.trb.org/View/1495256</guid>
    </item>
    <item>
      <title>The Impact of Ammonium Nitrate Species on Low Temperature NOx Conversion Over Cu/CHA SCR Catalyst</title>
      <link>https://trid.trb.org/View/1461492</link>
      <description><![CDATA[Cu/CHA catalysts have been widely used in the industry, due to their desirable performance characteristics including the unmatched hydrothermal stability. While broadly recognized for their outstanding activity at or above 200°C, these catalysts may not show desired levels of NOx conversion at lower temperatures. To achieve high NOx conversions it is desirable to have NO2/NOx close to 0.5 for fast SCR. However even under such optimal gas feed conditions, sustained use of Cu/CHA below 200°C leads to ammonium nitrate formation and accumulation, resulting in the inhibition of NOx conversion.         In this contribution, the formation and decomposition of NH4NO3 on a commercial Cu/CHA catalyst have been investigated systematically. First, the impact of NH4NO3 self-inhibition on SCR activity as a function of temperature and NO2/NOx ratios was investigated through reactor testing. Second, the formation of NH4NO3 was qualitatively measured through various adsorption and model reactions as well as its decomposition reactions by the temperature-programed desorption (TPD). In addition, the transient formation and accumulation of NH4NO3 under relevant process conditions were tracked by in situ DRIFTS spectroscopy to identify its formation and accumulation mechanisms. Last, a kinetic model was built to estimate the NH4NO3 inhibition impact on NOx conversion. This work provides insights into the limiting processes and SCR reactions at low temperatures that are important for addressing future low temperature NOx conversion needs.       ]]></description>
      <pubDate>Fri, 28 Jul 2017 13:00:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/1461492</guid>
    </item>
    <item>
      <title>Investigation of SCR Catalysts for Marine Diesel Applications</title>
      <link>https://trid.trb.org/View/1461488</link>
      <description><![CDATA[Evolving marine diesel emission regulations drive significant reductions of nitrogen oxide (NOx) emissions. There is, therefore, considerable interest to develop and validate Selective Catalytic Reduction (SCR) converters for marine diesel NOx emission control.         Substrates in marine applications need to be robust to survive the high sulfur content of marine fuels and must offer cost and pressure drop benefits. In principle, extruded honeycomb substrates of higher cell density offer benefits on system volume and provide increased catalyst area (in direct trade-off with increased pressure drop). However higher cell densities may become more easily plugged by deposition of soot and/or sulfate particulates, on the inlet face of the monolithic converter, as well as on the channel walls and catalyst coating, eventually leading to unacceptable flow restriction or suppression of catalytic function. To assess the risk of occurrence and potential mitigation measures for such phenomena, an experimental program is conducted with a number of vanadia based honeycomb SCR substrates. A range of relevant fuel qualities and exhaust conditions were surveyed in order to better understand the relevant phenomena and improve design capabilities for marine diesel NOx control systems.       ]]></description>
      <pubDate>Fri, 28 Jul 2017 13:00:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/1461488</guid>
    </item>
    <item>
      <title>Impact of Hydrothermal Aging on the Formation and Decomposition of Ammonium Nitrate on a Cu/zeolite SCR Catalyst</title>
      <link>https://trid.trb.org/View/1461487</link>
      <description><![CDATA[Low-temperature (T = 200°C) NOx conversion is receiving increasing research attention due to continued potential reductions in regulated NOx emissions from diesel engines. At these temperatures, ammonium salts (e.g., ammonium nitrate, ammonium (bi)sulfate, etc.) can form as a result of interactions between NH3 and NOx or SOx, respectively. The formation of these salts can reduce the availability of NH3 for NOx conversion, block active catalyst sites, and result in the formation of N2O, a regulated Greenhouse Gas (GHG). In this study, we investigate the effect of hydrothermal aging on the formation and decomposition of ammonium nitrate on a state-of-the-art Cu/zeolite selective catalytic reduction (SCR) catalyst. Reactor-based constant-temperature ammonium nitrate formation, temperature programmed oxidation (TPO), and NO titration experiments are used to characterize the effect of hydrothermal aging from 600 to 950°C. N2 adsorption (BET) surface area and diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) experiments are also conducted in order to correlate the morphological effects of hydrothermal aging with concomitant changes in ammonium nitrate chemistry. The insights provided herein support the diesel aftertreatment communities’ ongoing efforts to understand low-temperature chemical processes such as ammonium salt formation and their impact on emissions.       ]]></description>
      <pubDate>Fri, 28 Jul 2017 13:00:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/1461487</guid>
    </item>
    <item>
      <title>Effect of Transition Metal Ion Properties on the Catalytic Functions and Sulfation Behavior of Zeolite-Based SCR Catalysts</title>
      <link>https://trid.trb.org/View/1461483</link>
      <description><![CDATA[Copper- and Iron- based metal-zeolite SCR catalysts are widely used in US and European diesel aftertreatment systems to achieve drastic reduction in NOx emission. These catalysts are highly selective to N2 under wide range of operating conditions. Nevertheless, the type of transition metal has a significant impact on the key performance and durability parameters such as NOx conversion, selectivity towards N2O, hydrothermal stability, and sensitivity to fuel sulfur content. In this study, we explained the differences in the performance characteristics of these catalysts based on their relative acidic-basic nature of transition metal present in these catalysts using practically relevant gas species present in diesel exhaust such as NO2, SOx, and NH3. These experiments show that Fe-zeolite has relatively acidic nature as compared to Cu-zeolite that causes NH3 inhibition and hence explains low NOx conversion on Fe-zeolite at low temperature under standard SCR conditions. Similarly, relatively basic nature of Cu-zeolite results in more prominent SOx storage and performance deactivation in the presence of acidic contaminant like SOx and required higher temperatures for desulfation as compared to Fe-zeolite.       ]]></description>
      <pubDate>Fri, 28 Jul 2017 13:00:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/1461483</guid>
    </item>
    <item>
      <title>Development and Validation of Chemical Kinetic Mechanism Reduction Scheme for Large-Scale Mechanisms</title>
      <link>https://trid.trb.org/View/1434156</link>
      <description><![CDATA[This work is an extension to a previously reported work on chemical kinetic mechanism reduction scheme for large-scale mechanisms. Here, Perfectly Stirred Reactor (PSR) was added as a criterion of data source for mechanism reduction instead of using only auto-ignition condition. As a result, a reduced n-hexadecane mechanism with 79 species for diesel fuel surrogate was successfully derived from the detailed mechanism. Following that, the reduced n-hexadecane mechanism was validated under auto-ignition and PSR conditions using zero-dimensional (0-D) closed homogeneous batch reactor in CHEMKIN-PRO software. Agreement was achieved between the reduced and detailed mechanisms in ignition timing predictions and the reduced n-hexadecane mechanism was able to reproduce species concentration profiles with a maximum error of 40%. Accordingly, two-dimensional (2-D) Computational Fluid Dynamic (CFD) simulations were performed to study the spray combustion phenomena within a constant volume bomb. Both non-reacting and reacting conditions were applied in this study. Liquid and vapor penetration lengths were replicated for non-reacting diesel spray. For reacting diesel spray, both ignition delay and lift-off length were simulated. The simulation results were then compared to the experimental data of Sandia National Laboratories and No. 2 Diesel Fuel (D2) was designated as the reference fuel. Both liquid and vapor penetrations for non-reacting condition were well-matched, while ignition delay was advanced by 17.95% with 7.18% longer lift-off length for the reacting condition.]]></description>
      <pubDate>Thu, 05 Jan 2017 16:23:31 GMT</pubDate>
      <guid>https://trid.trb.org/View/1434156</guid>
    </item>
    <item>
      <title>The effects of lithium ions on chemical sequence of alkali-silica reaction</title>
      <link>https://trid.trb.org/View/1376343</link>
      <description><![CDATA[This paper presents the results of the investigation on the effects of Li+ ions on the chemical and physical changes in the cementitious system undergoing alkali-silica reaction (ASR). Specifically, this paper focuses on determining which chemical steps of ASR processes are affected by the presence of Li+ ions in the pore solution in order to provide better understanding of the role of Li+ ions in the mitigation process of ASR.  The results presented in this paper strongly support the hypothesis that the Li+ ions facilitate the formation of a physical barrier on the surface of reactive silica, and thus prevent further attack on the reactive sites by hydroxyl ions.]]></description>
      <pubDate>Tue, 15 Dec 2015 11:07:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/1376343</guid>
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