<rss version="2.0" xmlns:atom="https://www.w3.org/2005/Atom">
  <channel>
    <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" />
    <description></description>
    <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>
    </image>
    <item>
      <title>Quantum-Inspired Weight-Constrained Neural Network: Reducing Variable Numbers by 100 × Compared to Standard Neural Networks</title>
      <link>https://trid.trb.org/View/2689386</link>
      <description><![CDATA[Although quantum machine learning has shown great promise, the practical application of quantum computers remains constrained in the noisy intermediate-scale quantum era. To take advantage of quantum machine learning, we investigate the underlying mathematical principles of these quantum models and find that the quantum neural network with amplitude encoding is equivalent to a weight-constrained neural network. Motivated by this discovery, we develop a classical weight-constrained neural network. We find that this approach can reduce the number of variables in a classical neural network by a factor of 135 while preserving its accuracy. In addition, we develop a dropout method to enhance the robustness of quantum machine learning models, which are highly susceptible to adversarial attacks. This technique can also be applied to improve the adversarial robustness of the classical weight-constrained neural network, which is essential for industry applications, such as self-driving vehicles. Our work offers an approach to reduce the complexity of large classical neural networks, addressing a critical challenge in machine learning.]]></description>
      <pubDate>Mon, 20 Apr 2026 09:22:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/2689386</guid>
    </item>
    <item>
      <title>Elucidation of Flow Mechanisms Modulating Vehicle Wind Noise by Using Large-Scale CFD Simulation</title>
      <link>https://trid.trb.org/View/2692028</link>
      <description><![CDATA[In vehicle development, noise reduction is critical for ensuring passenger comfort. As electric vehicles become prevalent and engine noise is minimized, wind noise becomes more noticeable. Modulated wind noise, which causes a sense of fluctuation due to atmospheric turbulence, wind gusts, and preceding vehicle wakes, can cause significant discomfort. This noise is characterized as a high frequency sound above 1 kHz, modulated at low frequencies owing to the wind velocity and direction fluctuating at several Hz. The mechanisms behind wind noise modulation are not fully understood, and no established countermeasures have been developed. This is because wind noise perceived through the side window is primarily caused by the A-pillar vortex and door mirror wake, which coexist as complex turbulent flows around the vehicle. Therefore, identifying the source of modulated wind noise around vehicles under fluctuating wind conditions is difficult. This study aims to identify the source of the modulated wind noise and to clarify the underlying flow mechanisms. Numerical analysis (CFD) was used to simulate windy conditions, where the wind velocity and direction fluctuated at several Hz: successfully reproducing modulated wind noise around the vehicle. Using the modulation power spectrum to quantitatively evaluate the modulated wind noise, the contributions of A-pillar separation and door mirror wake to modulation power were clarified, identifying the source of the modulated wind noise around the vehicle. Additionally, vehicle shape effects were examined, such as door mirror presence and A-pillar modifications, which can suppress modulated wind noise. No significant difference in wind noise modulation power was observed with or without door mirrors, but it was found that the A-pillar shape modification contributed significantly to high frequency noise modulation power. To suppress modulated wind noise, designing an A-pillar shape that minimizes the separation flow, which intensifies owing to crosswind fluctuations, is crucial.]]></description>
      <pubDate>Tue, 14 Apr 2026 15:11:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2692028</guid>
    </item>
    <item>
      <title>Thermodynamic-based numerical modeling of induction–microwave heating in asphalt concrete: From laboratory to field scales</title>
      <link>https://trid.trb.org/View/2645719</link>
      <description><![CDATA[This study presents a thermodynamics-based framework for the coupled thermo-electromagnetic constitutive modeling and numerical simulation of induction heating in asphalt concrete. The numerical framework is developed to simulate the induction heating of asphalt concrete under electromagnetic fields at laboratory and field scales, enabling the establishment of a link between laboratory and field scale heating. Poynting’s theorem, representing the total energy in the electromagnetic field, is employed in the thermodynamic formulation to derive the storage and dissipated energy components. The constitutive model is then numerically integrated in the finite element (FE) framework. The laboratory results from the induction heating tests on asphalt concrete were used to calibrate and validate the constitutive model. The calibrated constitutive model is further applied to field-scale simulations to predict induction heating in asphalt pavements and to determine the power ratio required to achieve comparable heating rates between the laboratory and field scales. The simulation results confirm the effectiveness of the proposed model in predicting the induction heating of asphalt concrete. The simulation results reveal substantial differences in the heating process between the field and laboratory scales and highlight the advantages of the proposed model in predicting induction heating for practical applications and establishing a link between laboratory and field scales.]]></description>
      <pubDate>Fri, 20 Mar 2026 08:41:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2645719</guid>
    </item>
    <item>
      <title>An Empirical Investigation into the Hallucination of Mathematical Optimization in Travel Demand Model</title>
      <link>https://trid.trb.org/View/2613290</link>
      <description><![CDATA[This study examines the “hallucination of optimization” in transportation modeling, where traditional optimization methods yield seemingly valid results but fail to capture the complexities of real-world travel behavior. Focusing on the gravity model and origin-destination (OD) matrix estimation, the paper critiques the limitations of these approaches while exploring the transformative potential of big data. The gravity model, grounded in simplified assumptions about population, employment, and travel costs, often achieves high validation metrics like trip length distribution fit. However, it struggles to accurately replicate OD flows, revealing a gap between mathematical validity and practical accuracy. Similarly, OD matrix estimation relies on the quality of input data and performs poorly in scenarios with low-precision initial matrices, particularly at the traffic analysis zone (TAZ) level, despite strong overall metrics. This highlights the need to reassess conventional modeling techniques and leverage evolving data conditions to improve the accuracy of travel demand models.]]></description>
      <pubDate>Fri, 20 Feb 2026 15:28:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2613290</guid>
    </item>
    <item>
      <title>Public Transport: From NeTEx-Files to Mathematical Graphs</title>
      <link>https://trid.trb.org/View/2627530</link>
      <description><![CDATA[This paper focuses on the automatic extraction of routable mathematical graphs from open-data sources for the representation of real-world public transport networks. We start with the composition of the information required to define a graph for determining passenger journeys. Next, we explain the content of the used open data sources and demonstrate its appropriateness. Third, we apply our developed tool used for the graph derivation. The generated graphs provide a comprehensive representation of real-world multimodal public transportation networks.]]></description>
      <pubDate>Tue, 27 Jan 2026 16:16:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/2627530</guid>
    </item>
    <item>
      <title>Model-Based Design and Numerical Analysis of a Downsized Centrifugal Pump for Engine Cooling Applications</title>
      <link>https://trid.trb.org/View/2623924</link>
      <description><![CDATA[The water pump is the crucial component of the engine cooling system. It is usually designed considering as rated conditions the ones evaluated when the engine delivers its maximum power. This results in an overdesign of the pump, considering that almost never the engine delivers the maximum power, in usual operation. At these conditions, in fact, flow rate and pressure delivered reach the maximum values, which are not needed to cool the engine in most probable operating conditions. In fact, considering the real operating conditions during a typical driving mission or a homologation cycle, the mechanical power is far away from the maximum datum, as well as the cooling flow rate and pressure delivered by the pump. To a so unbalanced design for the pump corresponds a low efficiency of it, being the technology oriented to use a centrifugal type, whose efficiency is quite dependent on speed of revolution and flow rate delivered. Hence, modifying the design point of the pump causes a mechanical energy saving, improving the organic efficiency and reducing the efficiency penalization when it operates, as it happens always, at off design conditions.In this work, a model-based procedure to design a centrifugal pump in a more suitable engine working point from the point of view of the energy absorbed is considered. The procedure starts with an estimation of the engine thermal needs in different working conditions and on a driving cycle. Hence, a flow rate is targeted, and a pressure drop of the cooling circuit estimated, to have the specifics of the pump design. The model is able to evaluate all the hydraulic losses of the pump in its impeller and volute. The geometry generated has been refined and finally investigated through numerical CFD analysis. Subsequently, the turbulent flow field of the pump was analyzed in terms of static pressure, velocity, and kinetic energy distribution. The pump head and flow rate delivered were simulated using CFD techniques and compared with experimental results, assessing also the efficiency of the pump and the loss distribution. Finally, the pump performance has been evaluated along a driving cycle, to assess the energy absorbed during a real operating condition.]]></description>
      <pubDate>Thu, 13 Nov 2025 16:12:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/2623924</guid>
    </item>
    <item>
      <title>Numerical Analysis of Combustion Stability and Efficiency Improvement in Ammonia Engine Utilizing Passive Turbulent Jet Ignition (PTJI)</title>
      <link>https://trid.trb.org/View/2623921</link>
      <description><![CDATA[Ammonia, a carbon-neutral fuel, is a promising candidate for next-generation engine applications. However, its low flame speed (~7cm/s) and prolonged ignition delay (~10ms at stoichiometric conditions) impose significant challenges in achieving stable and efficient combustion across varying operating conditions. At high-speeds, incomplete combustion due to limited residence time reduces efficiency, while at low-speeds, ignition instability and low combustion temperatures hinder reliable operation. To address these challenges, the Passive Turbulent Jet Ignition (PTJI) system has been proposed to enhance turbulence-driven mixing and improve ignition characteristics. This study focuses on optimizing a PTJI system for ammonia-fueled engines using a three-phase methodology. First, the 800cc 2-cylinder gasoline engine was modified for ammonia using numerical analysis, and a baseline analysis of the combustion characteristics was conducted. Next, a turbulent intensity study within the PTJI system was performed to determine an optimal configuration for stable combustion. Results show that PTJI increased turbulent intensity by up to 120% compared to conventional spark ignition, enhancing flame propagation and reducing ignition delay. Finally, PTJI effectiveness was evaluated under both high-speed and low-speed conditions. At 2000rpm, PTJI increased combustion temperature by ~150K, improving ignition stability and reducing cycle-to-cycle variations, thereby improving the convergence of the analysis. At 3000rpm, PTJI accelerated flame propagation speed by ~50%, facilitating complete fuel-air mixture combustion and enhancing thermal efficiency. In conclusion, this research demonstrates that PTJI is a viable solution for overcoming the inherent limitations of ammonia combustion. By increasing turbulence intensity and improving flame propagation, PTJI enables more stable and efficient ammonia engine operation, offering a promising approach for future carbon-neutral powertrains.]]></description>
      <pubDate>Thu, 13 Nov 2025 16:12:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/2623921</guid>
    </item>
    <item>
      <title>Numerical Analysis of Deformation Adjustment on Wide Subgrade in
          Permafrost Region by Prefabricated Bridge-Type Pavement</title>
      <link>https://trid.trb.org/View/2614462</link>
      <description><![CDATA[Uneven thawing of frozen soil in the subgrade of wide highway leads to settlement                     difference of the pavement, which affects the driving comfort. The prefabricated                     bridge-type pavement mitigates the disease of wide subgrade in permafrost region                     by applying prefabricated slabs in the subgrade. In order to verify the                     deformation adjustment effect on wide subgrade of prefabricated bridge-type                     pavement, earth-filled pavement and prefabricated bridge-type pavement numerical                     models were established and subgrade mechanical behaviors were analyzed under                     frozen soil thawing in active layer, frozen soil thawing in localized                     deteriorated zone and vehicle loading. Comparative analysis of pavement                     settlement of earth-filled pavement and prefabricated bridge-type pavement under                     various cases is carried out. The results show that the maximum settlement of                     prefabricated bridge-type pavement decreases by about 32%~48%, and the                     settlement difference decreases by about 45%~65%, which has a good adjustment                     effect of pavement settlement.]]></description>
      <pubDate>Mon, 27 Oct 2025 17:04:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/2614462</guid>
    </item>
    <item>
      <title>Numerical Analysis of In-Nozzle Flow of Methanol Injectors for Large Marine Two-Stroke Engines</title>
      <link>https://trid.trb.org/View/2600421</link>
      <description><![CDATA[A statistical method for analyzing momentum deflection angles of fuel injectors based on Computational Fluid Dynamics (CFD) simulation of the internal nozzle flow is proposed. This method is especially relevant for large marine two stroke engines where the spray is often deflected due to an eccentric and asymmetric design of the internal injector geometry. Unsteady Reynolds-Averaged Navier-Stokes (URANS) CFD simulations are employed to analyze the internal flow of different cavitating injectors which have four and five nozzle holes, respectively, for a 50 cm bore and a 95 cm bore dual-fuel engine operating on methanol. The in-nozzle flow dynamics vary from one to another significantly. The use of the statistical analysis on the distribution of deflection angles at the fuel nozzle hole exit further assists at explaining differences in measured surface temperatures of the exhaust valve bottom and piston bowl. The corrected spray angles obtained from these in-nozzle simulations also serve as important inputs to the CFD engine combustion simulations for further in-cylinder analysis.]]></description>
      <pubDate>Tue, 16 Sep 2025 11:12:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2600421</guid>
    </item>
    <item>
      <title>Methods Proposed for Analysis of Vibrations of Railway Cars</title>
      <link>https://trid.trb.org/View/2407879</link>
      <description><![CDATA[Oscillations of carriages, which are especially noticeable when the speed of a railway train increases, require a detailed study, which presents significant mathematical difficulties. The article presents two methods for analyzing oscillations of railway cars: an estimated mathematical one based on solving differential equations, and a more accurate one based on simulation modeling in the MATLAB Simulink system. A reasonable simplification of the equations describing the oscillations makes it possible to consider the physics of the phenomena arising in this case more clearly, and a detailed account of the factors and parameters affecting the development of oscillations will make it possible to do this more accurately.]]></description>
      <pubDate>Fri, 25 Jul 2025 11:32:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/2407879</guid>
    </item>
    <item>
      <title>Effect evolution and lifespan estimation on ice-melting performance of salt-storage asphalt mixtures under dynamic water scouring</title>
      <link>https://trid.trb.org/View/2569251</link>
      <description><![CDATA[Road icing presents significant risks to traffic safety and leads to substantial economic losses. Existing research on salt-storage asphalt mixtures primarily focuses on short-term performance, with limited attention to their long-term durability and environmental impact. This study analyzed the evolution of the long-term performance of the ice melting characteristics of salt storage asphalt mixture, based on the meteorological conditions in western China. The performance of these mixtures was evaluated using conductivity measurements, ice-melting rate assessments, and adhesion tests at the ice layer interface under dynamic water scouring conditions. A fuzzy mathematical analysis method was applied to optimize the dosages of four salt-storing ice-melting aggregates. The ice-melting lifespan of the salt-storage asphalt mixtures was estimated under the optimal dosage. Results indicate that the ice-melting efficacy of these mixtures declines progressively with repeated dynamic water scouring cycles. After 10 h of scouring, the ice-melting performance stabilizes. The best ice-melting effect was achieved with a 60 % dosage of salt-storing snow-melting aggregates. An index for effective ice-melting performance lifespan was introduced. Under the optimal dosage, the complete salt release time due to the combined effects of vehicle load and dynamic water scouring was 4.6 years, while the effective ice-melting and snow-melting lifespan was 3.3 years. These findings provide a reference for the timely and effective suppression of road snow and ice accumulation, ensuring driving safety on salt-storing asphalt pavements.]]></description>
      <pubDate>Fri, 25 Jul 2025 11:31:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/2569251</guid>
    </item>
    <item>
      <title>Life Cycle Assessment of Hydrogen Generation through Steam Methane Reforming: A Focus on Co-Product Allocation between Steam and Electricity</title>
      <link>https://trid.trb.org/View/2571655</link>
      <description><![CDATA[This research presents a numerical analysis of the environmental impacts associated with using hot steam as a co-product in hydrogen production through Steam Methane Reforming (SMR) of renewable gas sources. As hydrogen production technology advances rapidly, reducing emissions and addressing environmental concerns, particularly greenhouse gas (GHG) emissions, have become essential. This study examines the SMR process with a focus on the environmental effects of utilizing hot steam as a co-product for electricity generation or facility heating. The analysis evaluates renewable feedstocks, including landfill gas, animal waste, food waste, and wastewater sludge, to determine their viability for sustainable hydrogen production. Key pollutants, such as carbon monoxide and nitrogen oxides, along with GHGs, are assessed to identify the most environmentally advantageous feedstock options. This work aims to provide insights to promote sustainable hydrogen production practices.]]></description>
      <pubDate>Tue, 08 Jul 2025 10:45:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/2571655</guid>
    </item>
    <item>
      <title>Analysis of Combustion Characteristics of a Small 2-Stroke Opposed Piston Engine Using an Optically Accessible Engine and Numerical Analysis</title>
      <link>https://trid.trb.org/View/2571623</link>
      <description><![CDATA[As global warming becomes more serious, decarbonization of internal combustion engines, which emit a large amount of carbon dioxide, is being promoted. It is predicted that many vehicles will still be equipped with engines in 2035, and a variety of powertrains will be required in the future. Therefore, we focused on the opposed-piston engine as an internal combustion engine specialized for power generation applications. The opposed-piston engine is characterized by its light weight due to the absence of a cylinder head, low S/V ratio due to the ultra-long stroke, reduced cooling loss due to the long stroke, and reduced vibration due to the offsetting of the reciprocating inertial forces of the left and right pistons. We believe that the engine for power generation can achieve the required high efficiency operation and vibration reduction. Therefore, in this study, combustion analysis of a two-stroke opposed-piston engine with features of low vibration, high efficiency, and high output was conducted using numerical analysis to solve the vibration problem, which is a demerit of engines for power generation, and to further improve thermal efficiency. In this study, a prototype opposed-piston engine with a displacement of 126.6 [cc] was built and used as an experimental device, but it is difficult to visualize the inside of a cylinder of an opposed-piston engine. Therefore, an experiment was conducted using a 63.3[cc] an optically accessible single-cylinder engine with the same bore and half the displacement and stroke, and the results were compared with the numerical analysis results of the an optically accessible single-cylinder engine, and the validity of the numerical analysis was confirmed. Therefore, we considered that the combustion analysis of an opposed-piston engine was also valid, and we conducted a combustion analysis of an opposed-piston engine using CONVERGE.]]></description>
      <pubDate>Tue, 08 Jul 2025 10:45:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/2571623</guid>
    </item>
    <item>
      <title>Experimental and Numerical Analysis of Direct Injection Process for Hydrogen-Fuelled Internal Combustion Engines</title>
      <link>https://trid.trb.org/View/2571722</link>
      <description><![CDATA[In the context of the clean transport sector, there has been growing interest in the use of hydrogen in internal combustion engines due to its potential to nearly eliminate all engine-out criteria pollutants, while maintaining high thermal efficiency through the use of a lean combustion process. In direct injection configurations, mixing process is significantly influenced by hydrogen jet dynamics. First, a comprehensive experimental campaign was conducted in a constant volume vessel to assess the performance of a hydrogen injector using the Schlieren technique. The jet behavior was analyzed by varying injector recess, injection pressure, and back pressure. Subsequently, the case study was replicated in a 3D Computational Fluid Dynamics (CFD) environment, addressing the complexities associated with modeling under-expanded jets. The model was first validated against experimental data, both in terms of jet morphology and through three geometric indices. Then, a simplified simulation approach was developed to significantly reduce computational effort while maintaining the reliability of the results. Among the analyzed parameters, injector recess was found to have the greatest influence on the jet shape and its evolution inside the chamber.]]></description>
      <pubDate>Tue, 08 Jul 2025 10:41:05 GMT</pubDate>
      <guid>https://trid.trb.org/View/2571722</guid>
    </item>
    <item>
      <title>Numerical Analysis of Variable Cross Section Weather-Strip Contact Sealing Performance &amp; Stick Slip Behavioral Study</title>
      <link>https://trid.trb.org/View/2552141</link>
      <description><![CDATA[This study focuses on the numerical analysis of weather-strip contact sealing performance with a variable cross-sectional design, addressing both static and dynamic behaviors, including the critical issue of stick-slip phenomena. By employing finite element modeling (FEM), the research simulates contact pressures and deformations under varying compression loads, DCE (Door Closing Efforts) requirements, typical in automotive applications. The analysis evaluates how changes in the cross-sectional shape of the weather-strip affect its ability to maintain a consistent sealing performance, especially under dynamic vehicle operations.The study also delves into stick-slip behavior, a known cause of noise and vibration issues, particularly improper/ loosened door-seal contact during dynamic driving condition. This study identifies key parameters influencing stick-slip events, such as friction coefficients, material stiffness, surface interactions, sliding velocity, wet/dry condition. Numerical simulations are used to predict stick-slip tendencies, and potential improvements, such as optimizing material properties or altering geometric profiles, are proposed.The results demonstrate that optimizing the variable cross-section can significantly enhance sealing performance, leading to better noise, vibration, and harshness (NVH) characteristics. Additionally, adjustments to material properties and geometric profiles are shown to reduce stick-slip effects, contributing to quieter and more reliable weather-strip systems in automotive applications. The findings of this study offer valuable insights for the design of more effective weather-strip systems in modern vehicles]]></description>
      <pubDate>Tue, 13 May 2025 10:11:05 GMT</pubDate>
      <guid>https://trid.trb.org/View/2552141</guid>
    </item>
  </channel>
</rss>